Technical guide | Steam boilers (PDF 12 MB)

Technical guide | Steam boilers (PDF 12 MB)
Technical guide
Steam boilers
1
Contents
7
Foreword
9
Introduction
11
A Utilising steam
12
History of steam generation
15
B What is steam?
16
Wet steam, saturated steam, superheated steam
18
19
B.1.2
B.1.3
Thermal capacity
Application areas
Contents
21
C Components of a steam boiler system
24
Steam boilers
26
32
38
41
42
C.1
C.1.1
C.1.2
C.1.3
C.1.4
44
Economiser (ECO)
46
Steam superheaters (SH)
48
Combustion system
49
49
50
51
52
C.4.1
C.4.2
C.4.3
C.4.4
C.4.5
54
Water treatment
58
59
60
C.5.1
C.5.2
C.5.3
64
Condensate management / treatment
65
65
66
67
69
C.6.1
C.6.2
C.6.3
C.6.4
C.6.5
70
Pumps
71
73
C.7.1
C.7.2
74
System-dependent thermal equipment
75
75
75
76
76
C.8.1
C.8.2
C.8.3
C.8.4
C.8.5
78
Pipework system
80
Flue system
Steam boilers
Boiler equipment
Multi-boiler system
Steam boiler in standby mode
Waste heat boilers
Combustion air
Liquid fuels
Gaseous fuels
Dual fuel burner
Wood combustion
Chemical water treatment (CWT)
Osmosis systems
Thermal water treatment (TWT)
Low pressure condensate
High pressure condensate
Condensate treatment
Sampling cooler
Dosing corrective chemicals
Feedwater pumps & control
Condensate pumps
Mixing cooler
T.D.S. expander and lye cooler
Exhaust vapour condenser
Feedwater cooler
Feedwater preheater
2/3
82
Internal system demand
83
83
C.11.1
C.11.2
84
Insulation of pipes, tanks etc.
85
85
C.12.1
C.12.2
86
Control system
87
C.13.1
88
Rules and regulations
88
C.14.1
93
D Component layout
96
Steam boiler selection
96
98
99
D.1
D.1.2
D.1.3
102
Product range
103
104
105
106
108
D.2.1
D.2.2
D.2.3
D.2.3.1
D.2.3.2
Steam boilers
Flame tube temperature monitoring (FTTM)
Economiser (ECO) operation
ECO output
Amortisation Economiser (AECO)
110
113
116
D.2.3.3
D.2.3.4
D.2.3.5
Utilising condensing technology
Superheater (SH) operation
Pressure / heat maintenance – steam boiler
118
Combustion systems
119
120
121
122
125
D.3.1
D.3.2
D.3.3
D.3.4
D.3.5
128
Water treatment
129
130
132
136
139
D.4.1
D.4.2
D.4.3
D.4.4
D.4.5
Internal power demand
Internal thermal power demand
Thermal insulation
Protection against the formation of condensate
Main functions
Legal framework
Steam boiler selection
Selection of the boiler pressure level
Waste heat boilers
Variable-speed combustion air fan
O2 control
Amount of fuel / fuel demand
Combustion air, supply air ducts
Acoustic emissions from monoblock / duoblock burners
Total deaeration system
Partial deaeration system
Chemical water treatment system (CWT softening system)
Function description – reverse osmosis system (RO)
Water analysis, general explanations
Contents
142
Condensate management
143
144
D.5.1
D.5.2
150
Pumps
151
160
D.6.1
D.6.2
162
Sizing the thermal equipment
163
168
171
174
180
D.7.1
D.7.2
D.7.3
D.7.4
D.7.5
182
Pipework
183
188
196
210
219
219
224
226
227
229
232
233
D.8.1
D.8.2
D.8.3
D.8.4
D.8.5
D.8.5.1
D.8.5.2
D.8.5.3
D.8.5.4
D.8.5.5
D.8.5.6
D.8.5.7
236
Flue system
237
239
240
242
D.9.1
D.9.2
D.9.3
D.9.4
244
Internal system demand
244
248
D.10.1
D.10.2
253
E Requirements and regulations
254
Basic requirements and regulations for the licensing procedure
254
E.1.1
265
268
271
E.1.2
E.1.3
E.1.4
Function description of open vented condensate systems
Function description of sealed unvented condensate systems
Feed pumps – criteria for design and operation
Condensate pumps – criteria for sizing and operation
Mixing cooler
T.D.S. expander
Exhaust vapour condenser
Feedwater cooler
Sampling cooler
Pipework
Specifications – materials, welding work
Pipework calculations and sizing
Strength, expansion, support spans, clearances, routing / mountings
Notes on design engineering of selected pipework systems
Steam pipes / steam distributors
Condensate pipes and systems
Boiler lye and blow-down lines
Feedwater – softened water – drinking water
Exhaust vapour, waste steam and discharge pipes
Fuel lines
Waste water and floor drainage systems
Planning and design information for connection pieces
Sizing the flue system
Chimney connection and design
Common flue system, merging of flue gas flows
Internal electrical system demand
Internal thermal system demand
Licensing procedure according to Section 13 of the [German]
Health & Safety at Work Act
Overview of German licensing procedures
Overviews and summary of application documents and their compilation
Overviews for compiling the application documents
4/5
272
Principle requirements and regulations for the installation of steam boilers
273
273
274
277
278
279
E.2.1
E.2.2
E.2.3
E.2.4
E.2.5
E.2.6
283
F Operation
284
Operating modes
284
286
287
F.1.1
F.1.2
F.1.3
293
G Appendix
Technical data collection and tables
294
[A 1]
Installation of category IV land-based steam boilers
Installation of category III land-based steam boilers (TRD 802)
Steam boiler system installation room
Acoustic emissions
Transportation and handling
Earthquake protection
Operating modes
Standards and regulations governing operation
Inspection intervals for boilers according to the Pressure Equipment Directive
296
297
298
302
304
305
306
309
313
314
315
316
317
318
319
320
311
322
323
324
325
Standard circuit diagram; other diagrams
can be found in the cover inside pocket
[A 2.1] Thermal insulation of pipes
[A 2.2] Contact protection insulation
[A 3]
Technical Guide on water quality – extract
[A 4]
Sketch of steam boiler container system
[Tb. 1.0] SI units / conversion table
[Tb. 1.1] 1. Conversion table – BTU / BHP / KW / t/h
[Tb. 2.0] Steam table (saturation state)
[Tb. 2.1] Properties of superheated steam
[Tb. 2.2] Properties of saturated steam
[Tb. 2.3] Enthalpy/Entropy
[Tb. 3.0] Internal pipe roughness
[Tb. 3.1] Pipe friction factor / Reynolds number
[Tb. 4.0] Pressure drop in steam pipes
[Tb. 4.1] Pressure drop in steam pipes – example
[Tb. 5] Conversion for the units of water hardness
[Tb. 6] Re-evaporation in condensate expansion
[Tb. 7] Pipe cross section for given steam parameters – example
[Tb. 8] Pressure drop in water pipes for a particular flow rate – example
[Tb. 9] Flow velocities (standard values)
[Tb. 10] Steam boiler inspection checklist
Literature references
326
Keyword index
336
Imprint
Introduction
6/7
Foreword
The global energy situation is characterised
by finite natural gas and mineral oil reserves,
simultaneously increasing consumption and
significant price increases. Furthermore, ever
increasing CO2 emissions are heating up the
atmosphere, leading to dangerous climate
change. This forces us to handle energy
responsibly. We need greater efficiency
and increased use of renewable energy
sources. As the largest consumer of energy,
the industrial sector can make a significant
contribution towards essential energy
savings and CO2 reduction through the use of
innovative and efficient heating technology.
The comprehensive product range from
Viessmann includes system solutions for
every type of energy source, which minimise
consumption of resources for convenient
heat provision and reliable steam supply, and
help protect the environment by reducing
CO2 emissions. Whether it be steam boilers
with integrated economisers and downstream
condensing heat exchangers for oil or gas
combustion, or wood-burning (biomass) steam
boilers for generating process steam with
downstream economisers, Viessmann has the
suitable solution.
The integration of heat recovery systems
requires precisely coordinated individual
components to achieve maximum efficiency
and to keep costs under control. This must be
based on proper system planning. Viessmann
began with the development and production
of powerful boilers for generating steam
several decades ago and can therefore call
on extensive experience. We would like you
to benefit from this experience through this
compact planning manual.
In selecting the subjects to be covered, we
have given priority to planning and engineering
reliability in the layout of steam boilers and
their components. After all, proper planning
and professional design are fundamental
prerequisites, not only for the trouble-free
and efficient operation of a steam boiler
system, but also for the safety of people and
the environment.
I am convinced that this planning manual
will be of welcome assistance to everyone
involved in the design of industrial steam
generation systems. I wish every success to
all those who use it.
Dr Martin Viessmann
Introduction
Vitomax production plant,
Mittenwalde
8/9
Introduction
This steam manual is intended as a supplement to such literature as the "steam" technical
series and the sales folder for steam industrial systems, with a focus on the design and
sizing of steam generation systems powered by the fuels oil, gas and wood (biomass), as
well as waste heat boilers up to a generator output of 75 t/h.
The manual must therefore be considered
as a "guideline" for the approach to be taken
in seeking a conclusive generator concept
on the basis of Viessmann-specific "main
components". System and heating engineers,
planners and production engineers will be
able to use this manual in conjunction with
the aforementioned technical brochures as an
additional reference work.
In spite of thorough checking, we cannot
completely rule out errors in the content or
printing errors that have been overlooked.
Viessmann expressly accepts no liability for
such mistakes. As a consequence, Viessmann
accepts no responsibility for the correctness of
statements made in this publication. Likewise,
Viessmann accepts no liability for any material
damage, personal injury or financial loss arising
from the use of this manual.
10/11
A Utilising steam
The aim of this manual is to explain the principles of steam generation in steam boilers
and describe the layout of components in a steam boiler system.
The properties of steam differ considerably
from those of the more frequently utilised heat
transfer medium, i.e. water. Consequently,
we must first turn to some fundamental
considerations regarding the medium "steam"
and steam generation. We will then introduce
the individual components of a steam boiler
system and provide information on its design,
installation and operation.
Where reference is made to standards and
legislation, we refer exclusively to European
regulations. By way of example, German
regulations are also taken into consideration,
but these cannot necessarily be applied to
other countries.
This manual only deals with the generation of
steam and does not address the subject of
"hot water boilers". The contents relate to "landbased steam", in other words the stationary
generation of steam, and consciously
exclude the features associated with mobile
generation, e.g. on board ships.
11
A Utilising steam
12
History of steam generation
A.1 Objectives
History of steam generation
Steam has been known to man since the first utilisation of fire. It occurred then as it does
now, unintentionally on quenching the fireplace with water or during cooking.
First considerations regarding the technical
utilisation of steam are attributed to
Archimedes (287 to 212 BC), who designed a
steam canon.
Leonardo da Vinci (1452 to 1519) made first
calculations on the subject, according to
which an 8 kilogram ball would be propelled
1250 metres when fired from such a canon.
Denis Papin is credited with the practical
execution of the pressure cooker (circa 1680).
This first pressure vessel was already
equipped with a safety valve, after a prototype
exploded during initial experiments.
The utilisation of the steam engine from circa
1770 made it essential to take a closer look at
the process medium water, both theoretically
and in practical terms.
12/13
Fig. A.1-1 Visualisation of boiler house
Practitioners included James Watt and
Carl Gustav Patrik de Laval, who both
became wealthy men as a result of marketing
their machines.
B.1 What is steam?
14/15
B What is steam?
In the context of this manual, we are not dealing with mixtures of air and steam, but
exclusively with dry steam generated in sealed unvented systems (steam boilers).
Note
Steam arises from the liquid or solid phase due
to evaporation or sublimation1). In the physical
sense, steam is gaseous water.
The pressures
referred to in this
manual are exclusively
positive pressures,
unless explicitly
stated otherwise.
Over time, the evaporation of water generates
a dynamic equilibrium where the same
number of particles are transferring from the
liquid or solid phase into the gaseous phase as
are reverting from the gas. At this point, steam
is saturated.
How many particles switch from one phase to
another is largely dependent on the pressure
and temperature of the system in question.
15
B What is steam?
16
Wet steam, saturated steam, superheated steam
18
B.1.2
Thermal capacity
19
B.1.3
Application areas
1) Sublimation: direct transition
of a material from the solid to
the gaseous state without prior
transformation into a fluid.
B.1 Foreword
Wet steam, saturated steam, superheated steam
Water evaporates at constant pressure on application of heat. Steam, on the other hand,
condenses on cold surfaces to form the finest droplets.
Fig. B.1–1
Properties diagram
At this point, the steam consists of a mixture
of fine droplets and gaseous, invisible water.
This mixture is referred to as wet steam
(Fig. B1.1-1 and B1.1-2).
Critical isotherms
Liquefying ice
under pressure
Critical
point
221.2
Melting point
Pressure [bar]
1
Normal
boiling point
0.006
Triple point
0.01
100
374.15
Temperature [°C]
Density ̖ at 100 °C and 1.01325 bar: 0.598 kg/m3 ; specific thermal capacity: cp= 2.08 kJ/(kg·K); thermal
conductivity: >0.0248 W/(m·K); triple point: 0.01 °C ฬ 273.165 K at 0.00612 bar; critical point: 374.15 °C at 221.2 bar
Above the critical point, steam and liquid
water can no longer be distinguished from one
another in terms of density, which is why this
state is referred to as "supercritical". This state
is irrelevant to the application of steam boilers.
16/17
Fig. B.1.1–1
Properties diagram
Water
Wet steam
Steam
Boiling the
tank content
Heat supply
Convection inside
the steam boiler
x=0
x>0
x = 0.2
x = 0.8
x<1
x=1
Wet steam, superheated steam,
e.g.: x = 0.8 means: 80 % of the water is available as steam
saturated steam
From a chemical viewpoint, supercritical
water has particularly aggressive properties.
Below the critical point, steam is therefore
"subcritical" and in equilibrium with liquid
water. If it is heated further in this range
following complete evaporation of the liquid
to a temperature above the associated
evaporation temperature,"superheated steam"
is created. This form of steam contains no
water droplets whatsoever and, as far as
physical characteristics are concerned, it is
also a gas and invisible.
The borderline between wet and superheated
steam is referred to as "saturated steam" or
occasionally also as "dry steam" to differentiate
it from wet steam. Most tabular values
concerning steam relate to this state
(see chapter G2, table 2).
Fig. B.1.1–2 T-s diagram
400
Critical point
x = Percentage by mass, steam [%]
%
%
%
20
x=
0%
0
10
=
=
80
x
x
x=
100
x = 60 %
200
x = 40 %
300
0
Temperature [°C]
Evaporation heat: 2250 kJ/kg
–100
–200
–273
0.0
2.0
4.0
6.0
Eutropy [kJ/(kg · K)]
8.0
10.0
In the T-s diagram, the range of wet
steam extends to the critical point at
Changes in state of water at 100 °C and 1 bar pressure
374 °C and 221.2 bar
B.1.2 Thermal capacity
Pressure cooker
The benefit of steam as a heat transfer
medium is its considerably higher thermal
capacity compared with water (Fig. 3). For
equal mass and temperature, the thermal
capacity or enthalpy of steam is more than
6-times greater than that of water.
The reasons for this lie in the substantial
energy required to evaporate water, which
is then contained in the steam that has
been created and is released again upon
condensation. This behaviour is well known
from boiling water, for example (Fig. B.1.2-1).
Fig. B.1.2–2
Temperature
Fig. B.1.2–1
To evaporate the contents of a saucepan, a
considerable period of time is required for heat
absorption via the hob or hotplate.
The energy transferred during this period
serves exclusively to evaporate the water; the
temperature of the water or steam remains
constant (100 °C at standard pressure)
(Fig. B.1.2-2).
This results in a substantial advantage for
steam as a heat transfer medium:
Compared with water, only one sixth of the
mass needs to be moved to transfer the same
amount of heat (Fig. B.1.2-3).
Evaporation characteristics
Boiling temperature
Boiling
x=0
x = 1 Time
Fig. B.1.2–3 Thermal capacity
Wärmeinhalt Wasserdampf: 2675,4 kJ
(1 kg, 100 °C, 1 bar)
Wärmeinhalt Wasser: 417,5 kJ
(1 kg, 100 °C)
Wärmeinhalt [kJ]
18/19
Fig. B.1.3–1
Steam boiler system
Slovenia/ Novo Mesto,
pharmaceutical production
B.1.3 Application areas
Steam is used in many industrial processes as
an energy source and as a medium for carrying
chemical substances.
Typical application areas are, amongst others,
the paper and building material industry,
refineries, the pharmaceutical industry and
processing of food on an industrial scale.
Steam drives turbines for the generation
of power, vulcanises rubber products and
sterilises packaging.
The generation of steam for industrial
purposes and its "handling" differ significantly
in some points from conventional heat
generation in heating technology using water
as the heat transfer medium.
In particular, high pressure steam generation
in the higher output range requires special
equipment for the systems concerned.
Typical applications for stationary steam
generation:
„Steam turbines,
„Steam heating systems (thermal energy
transfer medium),
„Chemical processes: as an energy source
and a carrier of reagents,
„Food processing industry (fruit juice
production, breweries, pasta and cheese
production, dairies, large bakeries); also
for sterilising,
„Fertilizer industry,
„Vulcanising rubber products,
„Pharmaceutical industry for sterilisation
purposes and as a carrier of therapeutic
agents,
„Building materials industry,
„Paper industry,
„Refineries (cracking crude oil),
„Wood processing (wood forming),
„Generation of a vacuum by displacing air
and subsequent condensation.
StoVerotec Deutschland in Germany,
Vitomax 200-HS, 4t/h, 16 bar
20/21
C Components of a steam boiler system
Steam generation requires a wide range of thermal equipment aside from the steam
boiler for preparing the feedwater or recovering energy, as well as pumps, burners
and other fittings.
In contrast to hot water boilers, steam
boilers are continuously supplied with "fresh"
feedwater. So that the constituents of water,
such as calcium, magnesium, oxygen and
carbon dioxide, do not permanently damage
the steam boiler over the course of time with
pitting corrosion or limescale deposits, for
steam boiler. Furthermore, burners, fittings
and pumps are required to provide the steam
boiler with the necessary energy. The interplay
between all of these components forms a
steam boiler system.
example, appropriate measures must be taken
to remove substances that are harmful to the
system are described in the following chapter.
The main components of a steam boiler
21
C Components of a steam boiler system
24
Steam boilers
26
32
38
41
42
C.1
Steam boilers
C.1.1 Boiler equipment
C.1.2 Multi-boiler system
C.1.3 Steam boiler in standby mode
C.1.4 Waste heat boilers
44
Economiser (ECO)
46
Steam superheaters (SH)
48
Combustion system
49
49
50
51
52
C.4.1 Combustion air
C.4.2 Liquid fuels
C.4.3 Gaseous fuels
C.4.4 Dual fuel burner
C.4.5 Wood combustion
54
Water treatment
58
59
60
C.5.1 Chemical water treatment (CWT)
C.5.2 Osmosis systems
C.5.3 Thermal water treatment (TWT)
64
Condensate management / treatment
65
65
66
67
69
C.6.1
C.6.2
C.6.3
C.6.4
C.6.5
70
Pumps
71
73
C.7.1
C.7.2
74
System-dependent thermal equipment
75
75
75
76
76
C.8.1 Mixing cooler
C.8.2 T.D.S. expander and lye cooler
C.8.3 Exhaust vapour condenser
C.8.4 Feedwater cooler
C.8.5 Feedwater preheater
Low pressure condensate
High pressure condensate
Condensate treatment
Sampling cooler
Dosing corrective chemicals
Feedwater pumps & control
Condensate pumps
22/23
78
Pipework system
80
Flue system
82
Internal system demand
83
83
C.11.1
C.11.2
84
Insulation of pipes, tanks etc.
85
85
C.12.1 Thermal insulation
C.12.2 Protection against the formation of condensate
86
Control system
87
C.13.1
88
Rules and regulations
88
C.14.1
Internal power demand
Internal thermal power demand
Main functions
Legal framework
C.1 Steam boilers
Vitomax 200-HS; 3.8 t/h,
13 bar in Belgium
Steam boilers
There are different types of steam boiler. Starting with kettles for boiling water to steam
engines and stationary steam boiler systems for industrial purposes or steam boilers in
power stations for generating power.
Viessmann only manufactures steam boilers
in the low and high pressure ranges up to
30 bar for the generation of saturated or
superheated steam, which are described in
the following text.
24/25
3 Vitomax 200-HS, type M235
C.1 Steam boilers
Fig. C.1–1 Thermal capacity (enthalpy) of steam
Heat content water steam: 2777.0 kJ
(1 kg, 180 °C, 10 bar)
Heat content water steam: 2675.4 kJ
(1 kg, 100 °C, 1 bar)
Heat content [kJ]
C.1
Steam boilers
A steam boiler is a sealed unvented vessel
designed for the purpose of generating
steam at a pressure higher than atmospheric
pressure. "Confining" the steam increases
the pressure and consequently the boiling
temperature. This also increases the energy
content of the generated steam (Fig. C.1-1).
The various boiler types can be differentiated
either by their design, combustion system or
fuel type.
Aside from their design, steam boilers are
defined by their steam output and permissible
operating pressure.
Essentially, two designs are available for the
generation of high pressure steam in the
higher output range:
„the water tube boiler and
„the flame tube/smoke tube boiler
(also referred to as shell boiler)
Fig. C.1–2
Cross-section through a steam boiler
In the first type, water is contained in tubes
that are surrounded by hot gas. This design
generally takes the form of a high speed steam
generator up to a pressure of approx. 30 bar or
as a water tube boiler up to approx. 200 bar.
Flame tube/smoke tube boilers cannot provide
such pressures on account of their design
principles. In these boilers, hot gas (flue gas)
flows through tubes that are surrounded by
water (Fig. C.1-2).
Depending on size, these boilers have a
permissible operating pressure of approx.
25 bar and deliver, for example, 26 tonnes of
steam per hour.
Flame tube/smoke tube boiler operating principle
Beyond the steam output described
here, there are also double flame tube
boilers designed according to the same
principles that deliver up to 50 t/h. The main
differences between this and other flame
tube boilers is the arrangement of 2 flame
tubes, each with separate hot gas flues, and
2 corresponding burners.
The design of the flame tube/smoke tube
boiler is suitable for meeting the demands
made of steam generation by the majority of
production processes – particularly in respect
of pressure and steam volume – safely
and economically.
26/27
Fig. C.1–3 Vitomax 200-HS
Fig. C.1–4 Vitomax 200-HS with integrated ECO
Vitomax 200 HS oil/gas high pressure steam boiler;
Vitomax 200 HS oil/gas high pressure steam boiler with
steam output: 0.5 to 4 t/h
mounted ECO; steam output: 5 to 26 t/h
Where low pressure steam (up to
0.5 bar) is required, this design is also the
conventional choice.
In Germany, more than 50 % of operational
high pressure steam boilers are shell boilers of
the three-pass design; a description that also
applies to the Vitomax 200 HS (Fig. C.1-3 and
Fig. C.1-4).
The design principle of shell boilers is
characterised by their large water capacity,
a large steam chamber and the resulting
excellent storage capacity. Consequently,
this type of boiler guarantees stable steam
provision, even in the case of wide and brief
load fluctuations.
The three-pass design enables particularly
economical, clean and hence environmentally
responsible combustion.
At the end of the combustion chamber, hot
gases flow through a water-cooled reversing
chamber into the second pass. The hot gases
arrive at the third pass through another
reversing chamber near the front boiler
door. Both hot gas passes are designed as
convection heating surfaces.
Since the hot gases exit the combustion
chamber through the rear reversing chamber
and no returning hot gases surround the
flame core – as is the case, for example, in a
reversing flame boiler – the flame can release
more heat and is therefore cooled down
more thoroughly. This feature, combined with
the reduced dwell time of the hot gases in
the reaction zone, reduces the formation of
nitrogen oxide.
The large evaporator surface combined with
the favourably designed steam chamber and
integral demister ensure the generation of
almost completely dry steam.
The three passes and consequent rapid
heat transfer allow high steam output to be
achieved with very short pre-heating times.
Heat transfer within the passes is split
as follows:
1st pass and reversing chamber approx. 35 %
2nd and 3rd pass/smoke tube pass approx. 65 %
Maximum steam boiler output is determined
by the European standard EN 12953 and is
compulsory for all manufacturers.
C.1 Steam boilers
Fig. C.1–5 Vitomax 200-HS
Sanovel / Istanbul
Single-flame tube shell boilers can be
manufactured with an output of up to
26 t/h when using gas as fuel; for fuel oil,
The design of the Vitomax 200-HS is
characterised by the following special features:
„Generously proportioned steam chamber
with low steam chamber load and
integrated steam dryer ensuring high
steam quality
„Expansion clearances according to trade
association agreement. The distances
between the smoke tubes as well as the
clearances between the smoke tubes and
the casing and the flame tube are all well
above requirements. This guarantees that
the shearing force on the facing floors
caused by different linear expansion in
the smoke tubes and the flame tube is
lower. The benefits for the operator are
a long service life and trouble-free boiler
operation. Cracking of the corner stays is
unheard of in Vitomax boilers
„Water-cooled burner operation. Vitomax
boilers are designed in such a way that
burners can be mounted without refractory
linings (exception: rotary cup atomisers ).
This guarantees a constant temperature
around the burner head, which in turn
the maximum output is 19 t/h. Maximum
permissible operating pressures are up to
30 bar, depending on output.
leads to consistently low NOx emission
levels. There is no reflection from the
refractory lining. Refractory linings must
be run dry according to a defined program,
which extends the commissioning period.
These are also wearing parts
„Water-cooled rear reversing chamber.
Vitomax boilers are designed in such a way
that the rear flue gas reversal is completely
water-cooled. As a result, energy latent in
the flue gases is made available exclusively
for heating the water. Fireclay bricks,
which are still used in the industry in some
places, heat up until they are red-hot and
have an effect on the flame on account of
their radiation, resulting in increased heat
radiation from the boiler. Furthermore,
fireclay bricks are wearing parts requiring
regular inspection and replacement
as necessary
28/29
„120 mm composite thermal insulation
ensures low radiation losses
„Vitomax boilers are equipped with a
sufficient number of inspection and access
ports to reach all important points inside
the boiler for the purpose of inspection.
This leads to the longest possible
intervals for internal inspection. See
chapter F.1.3.2
„Where corner stays are used, they must
be arranged in pairs. The stresses are well
below the permissible levels specified in
the steam boiler agreement [Germany].
Low stress in the component => longer
service life
„Vitomax boilers comply fully with all
applicable regulations
„The flame room geometry fulfils the
minimum standard according to the BDH
guideline. The boiler/burner combinations
in use are therefore non-critical
„Easy to open boiler doors and a
cleaning door at the end of the boiler
facilitate maintenance, hence reducing
operating costs
„Reliable technical specifications that stand
up to every scrutiny
„Viessmann cooperates actively in the
drafting of new guidelines and regulations,
thus setting new standards that represent
state-of-the-art technology
C.1 Steam boilers
Fig. C.1–5
Pyroflex wood combustion steam boiler
Wood combustion high pressure steam boiler
The MAWERA Pyroflex FSB high pressure
steam boiler with an operating pressure
of 6 to 25 bar can be used in conjunction
with the Pyroflex FSB flat moving grate
combustion system (combustion output 1 to
2 MW) and Pyroflex FSR (combustion output
1 to 15.3 MW). The Pyroflex FSB and FSR
combustion chamber for wood fuels (biomass)
is described in chapter C.4.5.
The boiler is designed as a 2-pass boiler
with cooling screen. The heat transfer is split
as follows:
1st pass approx. 80 %
2nd pass approx. 20 %
The design of the Pyroflex FSB / FSR steam
boiler is characterised by the following
special features:
„Modular construction – employable for
the Pyroflex FSB and Pyroflex FSR wood
combustion system
„Boiler can be positioned either directly on
the combustion chamber or freestanding
„Lowest thermal stresses due to the
cooling screen design
„Simple geometry of the parts subjected
to pressure
„Low operating costs due to the 2-pass
design (low pressure loss on the flue
gas side)
„Low radiation losses due to 120 mm
composite thermal insulation
„Large steam chamber, large evaporator
and an integrated demister for improved
steam quality
„Stable cover on top of the boiler included
in the standard delivery – this simplifies
maintenance and protects the thermal
insulation from damage
„Alternatively designed as a boiler
control platform
„A pneumatic cleaning system is
available as an option that increases the
boiler runtime
30/31
In some countries, test points are required for
monitoring the flame tube temperature in the
case of boiler output greater than the following
values:
„> 12 MW for oil combustion and
„> 15.6 MW for gas
(see also table D.2.2-1)
Such measuring points can be easily integrated
into all versions of the Vitomax 200-HS. On the
basis of corresponding national regulations,
temperature capturing systems with a minimum
of six test points in the flame tube are currently
required in the EU member states.
The capturing points detect impermissible wall
temperatures (permissible wall temperature
= f (flame tube material)) and break the boiler
safety chain (with burner shutdown).
Thermal combustion output (MW)
Old
New
Natural gas
13.65
18.20
Fuel oil
10.50
14.00
In addition to the normative limitation
according to DIN EN 12953-3, design
limitations must be provided according to
the regulations (TRD 306 clause 11) that are
"compulsory for all manufacturers" and that in
the final analysis are an important criterion for
determining the rated steam output (see notes
on selecting a steam boiler in chapter D 2).
In addition to the applicable trade association
agreement, monitoring of the flame tube
temperature is required in Germany according
to DIN EN 12953-3 as a compensatory measure
in respect of a possible increase in output.
Flange connector
with shield
Level 2
Flame tube temperature monitoring system
Level 1
Fig. C.1–6
Fuel
(Flame tube)
Control panel
(Flame tube)
Temperature test ports at the flame tube wall
Note
Where DIN EN 12953
or the TRD + applicable
trade association
agreement are employed,
the combustion heat
can be increased by 1/3
compared with the 'old'
TRD regulations trade
association agreement
1894/1 in respect of
the flame tube design
(subject to material
thickness, the material
itself, the internal
diameter and the fuel).
C.1 Steam boilers
C.1.1
Boiler equipment
The scope of the steam boiler encompasses
all safety equipment, control, display and shutoff equipment, the feedwater pump module,
the combustion system (burner) and a control
panel for activating all boiler and burner-specific
control equipment.
The selection of which individual components
are added to the steam boiler is governed
by the system operating mode and the fuels
required by the user.
Fig. C.1.1.1
Boiler equipment
Pos. 20 and 40: Quantity (1 or 2)
depends on country-specific requirement
Fig. C.1.1.2
Feedwater pump assembly
32/33
Fig. C.1.1.3
Boiler equipment
1
2
3
4
5
6
Platform
Control panel
Integral ECO
ECO-boiler connection line
Feedwater pump (module)
Burner
10
11
12
15
Level electrode (e.g. NRGT26-1)
Level electrode (e.g. NRG16-51)
Level electrode (e.g. NRG16-50)
Conductivity electrode
20
21
22
23
24
25
26
27
28
30
Safety valve
Ventilation shut-off valve
Steam shut-off valve
Feedwater shut-off valve
Feedwater non-return valve
Blow-down shut-off valve
Blow-down valve
T.D.S. shut-off valve
T.D.S. valve
Shut-off valve for ECO draining
40
41
42
43
44
45
46
Water level indicator
Nanometer
Maximum pressure limiter
Pressure transducer
Straight-through shut-off valve with cap
Dial thermometer
Sampling cooler
C.1 Steam boilers
Fig. C.1.1–4
Blow-down valve
Fitting out is based on TRD regulations and/or
EN standard 12953 using high quality systems
to the extent that they are approved by
regulations. The basis for approval is provided
by the corresponding EN standards or, where
such standards are unavailable, the appropriate
VdTÜV datasheets. This product selection
process enables a high level of system
availability and reliability.
Blow-down and T.D.S. valves on the steam
boiler are of particular importance. They are
required to ensure a consistently reliable
operation of the steam boiler. During
operation, sludge deposits form inside the
boiler that must be removed periodically.
Fig. C.1.1–5 Automatic blow-down
Blow-down
A special valve is used for this purpose
(Fig. C 1.1-4), the sudden and brief opening
of which and the associated suction effect
remove solids from the boiler floor. The valve
is opened manually, or automatically via a
blow-down program controller in the case of
unmanned operation, for a duration of 2-5 s.
Blow-down valves should ensure secure and
powerful closing by means of special design
features. This is optimised by installing the
cone from below, i.e. spring force and boiler
pressure combine to produce the maximum
possible closing force, hence ensuring that
the valve closes securely in spite of the
operational contamination.
In the case of so-called multi-boiler systems,
non-return valves must be provided in the
discharge pipe (EN 12953-6, paragraph 4.6.3).
34/35
Desalination
With steam generation, the salts dissolved in
the water stay behind and increase the salt
concentration level of the boiler water, primarily
at the water surface. For that reason, the T.D.S.
electrode is located in the upper section of the
steam boiler at the same height as the water
level. An excessively high salt concentration
results in the formation of a solid crust,
reducing the heat transfer and leading to boiler
corrosion and foaming, whereby the foam can
become entrained in the steam and have a
detrimental effect on the downstream system.
This reduces steam quality and the arising
water backup places additional strain on
valves. In addition, the function of the water
level controllers that ensure an adequate
water level in the boiler would be impaired.
For that reason, regulations require monitoring
[equipment] covering the boiler water quality,
which shuts down the boiler system if the
maximum permissible values are exceeded.
Essential requirements for the quality of
measurements are described in the VdTÜV
datasheet "Water Monitoring Equipment 100"
(WÜ 100) and form the basis for approval of
the measuring systems. Of particular note
here are the measuring quality, automatic
temperature compensation and the display of
temperature-compensated actual values. T.D.S.
valves are employed as a preventive measure
against the boiler system shutting down
in the event of excessive conductivity. The
T.D.S. controller with limit signal activates the
T.D.S. valve and also drains the boiler water.
The level controller makes up the water loss
with treated feedwater, hence reducing the
conductivity within the boiler. Fittings designed
especially for this purpose are also used on
the T.D.S. valves. Water is drained through the
stepped aperture at full differential pressure
(boiler / heat recovery) noiselessly and with
little wear.
Conductance is measured continuously by
a T.D.S. electrode fitted inside the boiler; it
triggers opening of the T.D.S. valve to a greater
or lesser extent when a specified set value is
exceeded (Fig. C.1.1-6 and C.1.1-7).
Fig. C.1.1–6 T.D.S. valve
Fig. C.1.1–7 Automatic desalination
For illustration purposes, the two valves are arranged opposite
one another. In reality, they are located next to each other on
the boiler wall
C.1 Steam boilers
Note
"Specially designed"
devices must be used
as water level limiters.
The need for a "special
design" arises if regular
checks take place
automatically in the
electrical and mechanical
parts of every device.
If faults occur in
the test sequence,
heating must be shut
down automatically
and transferred to a
safe state.
The limiters must
comply with the
requirements specified
in EN 12953-9 and an
additional risk analysis
must be carried out
in accordance with
EN 12953-6, paragraph
4.3.2, for every limiter
function and appropriate
levels of functional
safety established.
Note: Typical
requirements regarding
the safety integrity level
(SIL) of boiler safety
systems are never lower
than 2.
Function of the level electrodes
Example: boiler equipment for 72 h unattended
operation (BosB 72h). See also chapter F.1.1.
Each steam boiler is equipped with 2
connectors with an internal diameter of 100
and associated foam protection according
to EN 12953-9, paragraph. 2 electrodes
are mounted in each connector. Possible
combinations are WB+WR or WB+HW. Two
WB electrodes must not be mounted in a
common flange.
Fig. C.1.1–8
Electrodes, controlled operation
Set
WB – Water shortage limiter
WR – Water level controller
HW – Maximum water level limiter
In the case of operation without continuous
supervision, the water level must be controlled
in accordance with EN 12953. The regulations
do not specify anything in respect of the
quality of level control, i.e. periodic and
continuous control units may both be used.
Conductive multiple electrodes are often used
for controlling the interval; these switch a
pump ON/OFF and issue additional alarms by
means of the different lengths of the electrode
rods. Continuous control units are preferred
for systems > 2 t/h. A capacitive, continuously
active probe is used for capturing the filling
level in this instance. A set value controller
is used to activate the control valve or the
FU pump for continuous topping up.
Furthermore, EN 12953 requires two
independently operating devices that prevent
the water level falling below the minimum
value (limiter electrodes for min. water
level NW). These limiter electrodes must be
built into 2 connectors with corresponding
protective pipes. According to TRD 604,
an automatically operating device (limiter
electrode for max. water level HW) must be
mounted on the boiler for 72 h unattended
operation (BosB 72h), which reliably prevents
the maximum water level being exceeded.
Therefore, four electrodes are required for
monitoring on the water side according to 72 h
unattended operation (BosB 72h).
36/37
Fig. C.1.1–9
Electrodes, min. alarm
Fig. C.1.1–10
Max
Min
Electrodes, max. alarm
HW
NW
Safety chain LWL-alarm!
Safety chain LWL-alarm!
Boiler protection: see chapter D1
The limiter electrodes for minimum and
maximum water levels safeguard the boiler
operation with regard to exceeding or
falling below the HW and NW water levels
respectively. On response from the limiter
electrodes, an intervention is made in the
safety chain and combustion is shut down and
locked out.
In the case of the HW electrode, shutting
down combustion is only required if the
downstream heating surfaces could be at risk.
Otherwise, the HW electrode only intervenes
in the topping up device, switching it off until
the electrode re-emerges.
C.1 Steam boilers
C.1.2
Multi-boiler system
Multi-boiler systems (Fig. C.1.2-1) are used
for reasons of security of supply that must be
guaranteed by the steam boiler system, for
example in hospitals for sterilisation purposes
or when there is a varying demand for steam
over a given period (day/night, summer/winter).
Another reason for implementing a multiboiler system is the combination of a wood
combustion (biomass) steam system with an
oil or gas steam system. The wood combustion
(biomass) steam boiler is generally employed
as the base load boiler. Oil and gas steam
boilers are used as peak load and fail-safe
boilers. Temperature and steam pressure levels
are maintained in oil or gas steam boilers
by built-in indirect coils. The energy required
for this purpose is provided by the wood
combustion (biomass) steam system.
Fig. C.1.2–1
AMH Hospital, Chorzow, Poland –
3 high pressure Vitomax 200 HS
steam boilers with 2.4 t/h (8 bar)
supplying steam for the heating
system, the laundry and sterilisation
Steam boiler system in a hospital
The question as to how many boilers with
what output should be installed must be
considered in terms of the security of
supply and ensuring the lowest possible
operating costs.
With a single boiler system, account must be
taken of the fact that the boiler output range
only depends on the control range of the
combustion system. Advanced gas burners
with high output can be regulated down to
approx. 1/8 of maximum boiler output. The
boiler switches to intermittent operation if
steam demand falls below this control range.
Systems comprising several boilers are
predominantly operated with a sequential
control. The sequential control allows boiler
operation appropriate for the steam demand
from a viewpoint of the most economical
operating mode and a high security of supply.
Economical operation results from the
reduced number of burner start events and
boiler operation in the medium load range
with low flue gas losses and therefore higher
efficiency levels.
38/39
The sequence control PLC determines which
boiler is the lead boiler and the sequence of
other lag boilers. Boilers that are currently
undergoing modifications, for example, or
those that are not required for a longer period
as a result of reduced steam demand and have
therefore been preserved must be removed
from the sequence control.
Fig. C.1.2–2 Annual load curve or annual demand line
4500
4000
Total heat output
3500
Biomass heat
3000
kWh/h th
In principle, every boiler is equipped with its
own boiler control unit and can be regulated
and operated on a stand-alone basis. The usual
type of control unit is a programmable logic
controller (PLC). Sequence control, also by
means of a PLC, is higher ranking than the
individual boiler control units.
2500
2000
1500
1000
500
0
0
2000
4000
6000
h/a
The annual load curve or annual demand line portrays a
practical application of a wood combustion (biomass) steam
system (rated output 1500 kW) in combination with an oil or
gas steam boiler
8000
C.1 Steam boilers
Fig. C.1.2–3
Steam shut-off valve motor
The lead boiler is changed automatically after
a predefined period in a predefined sequence
in accordance with the PLC programming.
A lag boiler can be added to the sequence
if, for example, the operational boiler runs at
an output level of 80 %, for example, for a
specified period.
The lag boiler is fired up and the motorised
steam shut-off valve opens after the system
pressure has been reached (Fig. C.1.2-3),
allowing the boiler to feed steam into the
steam manifold.
Motorised steam
shut-off valve
Fig. C.1.2–4
PLC touch panel
A boiler is shut down when its output falls
below 35 %, for example. The lag boiler
becomes inoperative and the motorised steam
shut-off valve closes.
Pressure is maintained in the backup boilers
using a second control pressure that is lower
than the required steam system pressure.
This control system ensures the rapid
availability of the boiler in the event of
additional demand and the pressure vessel is
protected against corrosion occurring during
idle periods, as well as repeated loads.
PLC touch panel on the
"Vitocontrol" control panel
Fig. C.1.2–5
"Vitocontrol" control panel
All the actual setting values for the sequential
control must be defined separately for each
system and specified via the PLC (Fig. C.1.2-4
and Fig. C.1.2-5).
"Vitocontrol" control panel
with PLC touch panel
40/41
C.1.3
Steam boiler in standby mode
In the case of multi-boiler systems where, for
example, one steam boiler is used additionally
once a day for covering peak loads, it is
recommended that this peak load boiler is kept
under constant pressure. The same applies to
weekend production stoppages.
In this particular case, the steam boiler(s) is/
are kept under pressure, preferably at a low
pressure level.
This guarantees that the steam boilers can
deliver steam to the production process at
short notice and that, with the involvement of
the thermal water treatment system, the boiler
system is protected from oxygen ingress.
C1.3.1 Ways of maintaining pressure
A Pressure maintenance by means
of combustion
A second pressure level with a slight
overpressure (4 bar for example) is stored
in the PLC. The burner system raises the
pressure in the boiler to the specified level. The
burner enters standby mode as soon as the
pressure sensor in the boiler signals that the
set value has been reached.
The thermal water treatment system must also
be included here. This means that the TWT
container must also be kept under pressure to
avoid oxygen ingress.
B Pressure maintenance by indirect coil
In the case of multi-boiler systems, the boilers
can be kept under pressure by means of an
internal indirect coil that is built into the waterbearing part of the pressure vessel. The supply
of heating steam is controlled to maintain the
required parameters.
This presupposes that one steam boiler is
always available to supply medium to the
indirect coil (Fig. C.1.3.1-1).
Alternatively, the steam controller in the
indirect coil feed line can be dispensed
with in the event of constant parameters,
according to which the internal indirect coil can
be designed.
So that all boilers can be run alternately as
lead boiler, it is recommended that each steam
boiler is equipped with an internal indirect coil.
Fig. C.1.3.1–1
Pressure maintenance by indirect coil
C.1 Steam boilers
Fig. C.1.4–1 Waste heat boiler
WB/
DR 1 DR 2 DB WR WB2
SIV
D
CHP
&
'
LFE
DR
DB
WB
D
SIV
LFE
WSA
ABV
PK
ASV
Pressure regulator
Pressure limiter
Water level limiter
Steam connector
Safety valve
Conductivity electrode
Water level indicator
T.D.S. valve
Sample cooler
Blow-down valve
C.1.4 Waste heat boilers
Waste heat boilers utilise the heat present in
flue gases from combustion processes or in
hot exhaust air flows from industrial processes
to generate hot water, saturated steam or
superheated steam.
Function and layout
Viessmann waste heat boilers are designed
according to the flame tube/smoke tube boiler
principle. In so doing, hot flue gas is directed
through pipe bundles, where heat present
in the gas is transferred to water inside the
boiler body.
By contrast, in flue gas heat exchangers, the
water flows through pipe bundles while the
flue gas flows around the pipes inside the heat
exchanger housing. Flue gas heat exchangers
are preferred when using "cooler" flue gases
for generating DHW.
WSA ABV PK
ASV
Flue gas collectors are attached to the inlet
and outlet sides of the waste heat boilers,
where cleaning apertures are located and flue
pipes connected.
To minimise radiation losses, the waste heat
boiler is fitted with 120 mm composite thermal
insulation with a painted sheet steel jacket.
Like all Vitomax boilers, the waste heat boiler
stands on a base frame that spreads the load
across a large area of the floor.
42/43
Fig. C.1.4–2
Single flue waste heat boiler
There are two different types of
Viessmann waste heat boiler:
Waste heat boilers without
additional combustion. Here, only
the flue gases/exhaust air flows
are used to heat water or generate
saturated steam
Fig. C.1.4–3 Vitomax 200 HS shell boiler for generating steam with additional waste heat flues
Hot water or steam boilers with
waste heat utilisation. These are
conventionally fired boilers that make
additional use of waste heat
The choice of which boiler type is employed
depends on the customer-specific conditions
of use
C.2 Economiser
Economiser (ECO)
An economiser is a flue gas/water heat exchanger that is integrated into the steam boiler
or mounted as a separate assembly on the flue gas collector or behind the boiler. With
steam boilers, such economisers are used to preheat the feedwater. They help to improve
the energy yield and hence increase the efficiency of the boiler system.
The flue gas temperatures at the boiler
outlet are approx. 60 – 80 K higher than the
temperature of the saturated steam. Due to the
laws of physics, this value cannot be further
reduced economically during the heat transfer.
From this comparatively high flue gas
temperature, a combustion efficiency of
88 to 91 % is calculated at 100 % boiler
output. Consequently, the flue loss can be as
high as 12 %.
The German Immissions Act (BImSchV)
requires a maximum flue loss of 9 %.
Therefore, in many cases, feedwater preheaters (economisers – ECOs) are used in
steam boilers to achieve values below this limit.
This is also the most economical way to
improve efficiency.
In principle, ECOs are located downstream of
the 3rd pass in shell boilers or downstream of
the 2-pass boiler (wood combustion (biomass)
boiler Pyroflex FSB / Pyroflex FSR) and reversing
flame boilers. Here, flue gases are cooled
down further by the boiler feedwater flowing in
countercurrent fashion (Fig. C.2-1).
The thermal layout is established in accordance
with the given parameters of flue gas
volume and temperature, feedwater volume
and temperature and the required flue gas
temperature downstream of the ECO.
44/45
Venting via
the roof
Safety valve
discharge pipe
Fig. C.2–1 Viessmann (Mawera) wiring diagram – steam boiler
Feedwater
TI
PI
TI
Vitomax 200 HS or
Pyroflex FSB/Pyroflex FSR
Drain
Diagram for an ECO that can be
isolated with valves and bypass
Depending on the size of the heating surface,
flue gases are cooled to approx. 130 °C.
There are two sizes of economiser in the
product range for Vitomax steam boilers, for
cooling flue gases to approx. 180 °C or 130 °C
(standard) respectively. Economisers are
available for the Pyroflex FSB / Pyroflex FSR as
standard for cooling flue gases to approx.
130 – 180 °C subject to pressure level.
Fig. C.2–2 Without economiser
The feedwater is heated from 102 °C (inlet
temperature) to approx. 135 °C (at a flue
gas temperature of 130 °C). Upon customer
request, different values can be calculated
and offered.
Hence, a combustion efficiency of 95 % is
achievable (Fig. C.2.-2 and Fig. C.2-3) at an
operating pressure of 12 bar.
Fig. C.2–3 With economiser 200
.
.
.
.
.
.
.
.
.
.
Boiler efficiency [%]
Boiler efficiency [%]
.
.
.
.
.
Boiler output [%] relative to the rated output
A
B
C
D
E
F
G
H
I
Operating pressure 5 bar
Operating pressure 7 bar
Operating pressure 9 bar
Operating pressure 12 bar
Operating pressure 15 bar
Operating pressure 17 bar
Operating pressure 19 bar
Operating pressure 21 bar
Operating pressure 24 bar
.
Boiler output [%] relative to the rated output
A
B
C
D
E
F
G
H
I
Operating pressure 5 bar
Operating pressure 7 bar
Operating pressure 9 bar
Operating pressure 12 bar
Operating pressure 15 bar
Operating pressure 17 bar
Operating pressure 19 bar
Operating pressure 21 bar
Operating pressure 24 bar
Boiler efficiency, including radiation
losses, as a function of operating
pressure (residual oxygen content
in flue gas 3 %, feedwater
temperature 102 °C)
C.3 Steam superheaters
Steam superheaters (SH)
Many industrial applications make specific demands of the steam parameters.
Fig. C.3–1 Vitomax 200-HS
Vitomax 200-HS with superheater,
22 t/h, 10 bar, in production, (installed
in Lithuania)
In some processes, steam is required at higher
temperatures than those available at saturated
pressure. This makes it necessary to superheat
the steam. For this purpose, Viessmann has
designed specific steam superheaters that are
installed between the second and third pass of
the Vitomax 200-HS.
With such a solution, the superheater can
generate steam at a temperature approx. 50 K
higher than the saturated steam temperature.
46/47
Fig. C.3–3
Steam boiler with regulated superheater
Superheated steam
M
Saturated steam
Fig. C.3–4
Steam boiler with unregulated superheater
Superheated steam
Saturated steam
C.4 Combustion systems
Combustion system
Burners are entrusted with the task of making the energy content of fuels
available in the form of heat.
Normally, liquid and/or gaseous fuels undergo
combustion in shell boilers. Increasingly,
however, wood combustion (biomass) steam
systems are also being used, with a gas or oil
steam boiler acting as a peak load backup.
48/49
C.4.1
Combustion air
Gas and oil can only burn with the addition of
oxygen (air). For this reason, every burner is
fitted with a combustion air fan.
Depending on the arrangement, a
differentiation is made between mono and
duo-block burners.
„Mono-block: fan mounted on the burner
„Duo-block: fan mounted separately
The combustion air fan is designed to deliver
the necessary stoichiometric air volume plus
the required supplement of approx. 10 % to
bridge the system-specific pressure drop.
This includes the pressure drop of the
boiler, the burner, the economiser and
the flue gas silencer, as well that of the
connecting pipework.
To ensure clean combustion and a long
service life of both the boiler and the burner,
the temperature of the intake combustion
air should be between 5 °C and 40 °C.
In addition, the air should be free from
corrosive constituents, such as chlorine or
halogen compounds.
C.4.2
Note
Liquid fuels
Fuel oils are categorised as follows:
„HEL: extra light fuel oil, net cv = 42.7 MJ/kg
„Heavy fuel oil1): heavy oil, net cv =
40.2 MJ/kg
DIN 51603 T1 and T3
describe the minimum
requirements for the
aforementioned fuel
oils. Furthermore, there
are oils, particularly in
countries outside Europe,
that cannot be assigned
to the above categories,
but that are commonly
used for combustion.
Oils differ in composition from country to
country. There are different burner versions for
the various oil types. A differentiation is made
between pressure atomisers, steam pressure
atomisers and rotary cup atomisers.
Pressure atomiser
Here, oil is atomised into an oil mist by means
of pump pressure through a nozzle. These
burners are primarily used to atomise light fuel
oil (Fig. C.4.2-1 and Fig. C.4.2-2).
Fig. C.4.2–1
Pressure atomiser burner
(Source: Weishaupt)
Fig. C.4.2–2 Cross-section through a pressure atomiser burner
Primary nozzle
Secondary nozzle 1
Secondary nozzle 2
Primary air
Secondary air
Secondary nozzle 3
(Source: Weishaupt)
1)
The comment on page 72
C8.5 must be observed in the
combustion of heavy fuel oil/masut
and a steam boiler with economiser.
C.4 Combustion systems
Note
For the dimensioning of
fuel lines, see Section
D.8.5.6
Steam pressure atomiser
Here, oil is atomised in the burner head with
the aid of steam. This process is usually only
employed in output ranges above those of the
shell boilers considered here.
C.4.3
Rotary cup atomiser
(also referred to as rotation atomiser)
Here, the oil is fed into a rapidly rotating
cup on the facing side. Oil migrates towards
the chamber due to the rotation and conical
internal shape of the cup and is finely
atomised at the edge of the cup due to the
centrifugal force and the effects of atomising
air being expelled at high velocity.
Natural gas is a gas consisting mainly of
methane (CH4). Its consistency may vary
subject to its origin.
Rotary cup atomisers are preferred for the
combustion of heavy fuel oil (Fig. C.4.2-3).
They are also suitable for the combustion of
light fuel oil, oil residues, such as oil-grease
mixtures or degreasing residues, for animal
fats or cooking oils as well as for rape seed oil.
Gaseous fuels
Here, we shall consider the natural gas group.
No further consideration is given to LPG or
town gases due to their minor significance.
Normally, natural gas contains such
constituents as inert gases (non-combustible
constituents) and even heavy hydrocarbons.
Natural gas is heavier than town gas, but
lighter than air.
Natural gas E: net cv = 36 MJ/kg
Natural gas LL: net cv = 32 MJ/kg
In many cases, biogas or sewer gas can be
mixed with natural gas; frequently, both gases
can also undergo combustion without adding
natural gas.
The change in net calorific value must be
observed when mixing gases in order to
identify the need for any burner adaptation
and/or use of a special burner.
Fig. C.4.2–3
Rotary cup atomiser
Generally speaking, the sulphur content of
the gases used must be considered when
designing a system, as high quality materials,
such as stainless steel, are required for fittings
that are in contact with the gas.
(Source: Saacke)
50/51
C.4.4
Dual fuel burner
Fig. C.4.4–1
Oil/gas low NOx pressure atomiser
These are generally burners that can be
operated with gas or oil (Fig. C.4.4-1).
Switching between fuels take place manually
or automatically, for example, based on
blocking times prescribed by the gas supplier
that require a temporary changeover to oil.
This version is preferred for larger systems to
safeguard continuity of supply.
(Source: Saacke)
Fig. C.4.4–2 Vitomax 200-HS with oil burner
C.4 Combustion systems
Fig. C.4.5–1 View of the MAWERA Pyroflex flat moving grate combustion chamber
Fig. C.4.5–2
Fuel types (wood fuels)
C.4.5 Wood combustion
Apart from companies directly involved in
the timber industry, an increasing number of
business enterprises and industrial concerns
(non-wood processing) are opting for wood
(biomass) as a fuel. This is subject to less
severe price fluctuations than fossil fuels, it is
sourced from more politically stable regions
and, due to its sustainability and CO2 neutrality,
wood makes a significant contribution to a
future worth living.
The MAWERA Pyroflex FSB and FSR are used
as the wood combustion system (combustion
chamber with flat moving grate) in steam
systems. The essential difference between
the Pyroflex FSR and the Pyroflex FSB is the
volume of the combustion chamber and the
size of the grate, where the Pyroflex FSB
represents the more compact wood
combustion system.
Due to the inertia of combustion, the quantity
of steam present in the boiler must be shut
down using a separate valve in the case of
quick-acting steam consumers.
Structure and function
The Pyroflex flat moving grate is not only
suitable for the combustion of biomass
but also for burning special fuels with an
elevated ash content or fuels containing a high
proportion of foreign matter, e.g. sand, metal
residues, etc.
The major benefits of Pyroflex flat moving
grate combustion are, on the one hand, the
ability to use different biogenic fuels and, on
the other hand, a lower dust content in the flue
gas, due to the static fuel bed.
Low NOx reduction technology
The combustion chamber is supplied as
standard with low NOx reduction technology
for fuels with a high nitrogen content. The
low NOx combustion chamber is a twostage combustion chamber with an air stage
for reducing NOx emissions. In addition,
this effect is amplified by the use of a flue
gas recirculation system. The geometry of
the combustion chamber in the reduction
zone (primary zone) and the oxidation zone
(secondary zone) was developed by means of
fundamental research on our test facility.
52/53
Fuel discharge /
fuel transport
Mawera push-bar discharge systems or silo
discharge systems are employed for drawing
fuel from silos or bunkers. Chain conveyors,
push bars or tubular screw conveyors can be
used as fuel transport systems, subject to
structural situation and the fuel grain size.
Fig. C.4.5–3
Sectional view of the Pyroflex flat moving grate combustion system
1
7
Flue gas dust extraction
Multi-cyclone separators for fuel-dependent
clean gas dust levels of < 60 to < 150 mg/Nm³
(standard oxygen content 11 or 13 %) are
employed as flue gas dust extraction systems.
For clean gas dust levels of 10 to 50 mg/Nm³,
fabric filters, metal fabric filters or electric
filters are employed, subject to fuel used.
Mawera Logic
The system is controlled and regulated
by the Mawera Logic microprocessor
control unit with touch screen. A modem
for remote maintenance, a process control
system (MaVis) and a tele-stand-by unit are
also available.
The design of the Pyroflex flat moving
grate is characterised by the following
special features:
„Minimal radiation losses due to complete
insulation of the entire boiler system
„Static ember bed resulting in significantly
lower emissions
„Flame temperature control system with
integrated, adapted residual oxygen
regulation
„State-of-the-art microprocessor controller
regulates the system with automatic
detection of fuel moisture content,
modulating from 25 to 100 % load
subject to compliance with the prescribed
maximum emission levels
2
3
„Controlled burnout due to flat moving grate
divided 2 or 3 times with different speeds
„High levels of resistance to wear due to
generously dimensioned grate area, as
well as water cooling in the case of the
hydraulic slider being used
„Low grate throughput due to overlapping,
pre-tensioned grate bars; permanent
automatic ash removal
1.
2.
3.
4.
5.
6.
7.
4
5
Secondary air injection nozzles
Low NOx combustion chamber
Flat moving grate
Fuel supplied by means of
hydraulic slider or screw
conveyor
Primary combustion air supply
Automatic combustion chamber
ash removal
Flue gas recirculation “via grate”
C.5 Water treatment
Water treatment
The purest form of naturally occurring water is rainwater.
However, rainwater contains gaseous (solute)
elements absorbed from the atmosphere.
Essentially, these are oxygen, nitrogen and
carbon dioxide, with sulphur compounds ("acid
rain") also being found increasingly. When
rainwater soaks away into the ground, further
substances are picked up by the water, such
as iron and lime. The composition of the water
therefore also depends on the path it takes on
"passing through" the ground.
The purpose of water treatment is the
provision of treated water that has no
detrimental effect on the boiler operation.
This means that spurious constituents of
the water must be removed or bound by
adding chemicals.
Surface water, well water or pretreated
drinking water can be used as raw water
(i.e. untreated water for boiler operation).
Constituents, such as suspended matter,
turbid matter, organic contaminants, iron and
manganese compounds, can be present in
surface water and well water that need to be
removed in the preliminary water treatment
stages. These pre-treatments are not required
for drinking water.
54/55
General explanations
The water-steam system is subject to
quality requirements regarding permissible
constituents. Depending on the pressure
stage of the generated steam, limits must
be complied with that are specified in the
technical guide "Standard values for water
quality", chapter G1 (A3).
The feedwater must be treated in order to
comply with these standard values. The
processes employed for this purpose generally
comprise a combination of chemical and
thermal water treatment.
The hardeners contained in the untreated
water are bound together and extracted in
a softening system (see also chapter C.5.1
Chemical water treatment). Furthermore,
gases are dissolved in water that are released
on heating the water in the steam boiler.
These gases would inevitably result in
corrosion inside the steam boiler as well as the
downstream steam system.
For this reason, the top-up water from the
softening system is thermally treated, i.e.
deaerated, in a deaerating system together
with the condensate returned from the
consumer system (see also chapter C.5.3
Thermal water treatment).
To ensure that the required residual oxygen
content in the feedwater (0.02 mg/l) is
maintained, chemicals are added to bind
the residual oxygen. The exclusive use of
chemicals to bind the entire quantity of oxygen
is uneconomical in most cases.
C.5 Water treatment
Note
Feedwater and boiler
water requirements are
defined in EN 12953
Part 10, TRD 611 and in
the Viessmann technical
guide "Water quality“
(Fig. C.5-1, Fig. C.5-2
and chapter G1 A3).
Fig. C.5–1
Requirements for saline boiler feedwater
Permissible operating pressure
bar
0.5 ู PS ู 20
General requirements
PS > 20
Colourless, clear and free of undissolved substances
pH value at 25 °C
>9
>9
Conductivity at 25 °C
μS/cm
Only standard values applicable to boiler water
Total of alkaline earths
mmol/litre
< 0.01
Oxygen (O2)
mg/litre
0.05
< 0.02
Bound carbon dioxide (CO2)
mg/litre
< 25
< 25
Iron, total (Fe)
mg/litre
< 0.2
< 0.1
Copper, total (Cu)
mg/litre
< 0.05
< 0.01
Oxidability
mg/litre
< 10
< 10
Oil, grease
mg/litre
<1
<1
Organic substances
---
See comment
< 0.01
(Ca2+ + Mg2+)
(Mn VII ൺ Mn II) as KMnO4
Note
In general, organic substances are mixtures
of different compounds. The constitution
of such mixtures and the characteristics of
their components when subjected to boiler
operating conditions are hard to predict.
Organic substances can decompose into
carbon dioxide and other acidic products that
Note
The TRD and EN 12953
require "appropriate
treatment and
monitoring of the
feed and boiler water"
for the operation of
steam boilers.
Fig. C.5–2
would increase the conductivity and result in
corrosion and deposits. They can also lead to
the formation of foam and/or coatings that
must be kept to the minimum levels possible.
The TOC content (Total Organic Content) must
also be kept to a minimum (<10 mg/litre).
Boiler water requirements
Saline operation,
Low salt operation,
feedwater conductivity
feedwater conductivity
> 30 μS/cm
Permissible operating pressure
bar
0.5 ู PS ู 20
≤30 μS/cm
PS > 20
PS > 0.5
General requirements
Colourless, clear and free of undissolved substances
pH value at 25 °C
10.5 to 12
10.5 to 11.8
10 to 11*1*2
0.1 to 1.0*1
Acid capacity (KS8.2)
mmol/litre
1 to 12*3
1 to 10*3
Conductivity at 25 °C
μS/cm
< 6000*3
See Fig. C.5-3*3
< 1500
Phosphate (PO4)
mg/litre
10 to 20
10 to 20
6 to 15
Silicic acid (SiO4)*4
mg/litre
Pressure-dependent, see Fig. C.5-4
Notes on Fig. C.5.2:
see technical guide on water quality,
Appendix A3
56/57
Fig. C.5–3
Max. boiler water conductivity
Maximum permissible boiler
water direct conductivity, subject
to pressure
Fig. C.5–4
Max. boiler acidity
࿆This level of alkalinity is no longer permissible > 20 bar
࿇KS 8.2 – value in mmol/l
Maximum permissible boiler
water silicic acid content (SIO2)
subject to pressure
C.5 Water treatment
C.5.1 Chemical water treatment (CWT)
Softening by means of ion exchange
The alkaline earths calcium and magnesium
are dissolved in water in the form of ions.
These elements are referred to as hardeners.
Under the influence of heat during boiler
operation, these compounds would form
"boiler scale" that is deposited as a solid
coating on the heating surfaces.
This coating prevents heat transfer from the
combustion to the water side. Initially, this
would result in higher flue gas temperatures
and therefore in reduced efficiency. As the
boiler scale thickens, the absence of cooling of
the heating surfaces leads to their destruction.
For this reason, water standards stipulate
softened feedwater.
Process of boiler scale formation CaCO3 under
the influence of heat:
Ca(HCO3)2 ----> CaCO3 + H2O + CO2
Fig. C.5.1–1
CWT
Double-pendulum softening system
Systems with ion exchange resin are used
for softening the water. Ion exchangers are
spherical synthetic resins with absorbed active
groups. As an active group, ion exchangers
for softening water have absorbed sodium
ions. When the hard water runs over the ion
exchanger, the absorbed sodium ions are
exchanged for calcium and magnesium ions
that are dissolved in the water. The hardeners
that are detrimental to boiler operation are
thereby removed from the water.
Once the ion exchanger is exhausted, i.e.
all sodium ions have been exchanged for
calcium and magnesium ions, it is regenerated
with a sodium chloride solution (rock salt).
The sodium ions are channelled over the ion
exchange mass in the excess and displace
the absorbed hardeners. Thereafter, the ion
exchanger is operational again. This process
can be repeated without limitations.
Charging:
2R – Na+ + Ca++/Mg++
---> R2 – Ca++/Mg++ + 2Na+
Regeneration:
R2 – Ca++/Mg++ + 2Na+
---> 2R – Na+ + Ca++/Mg++
R = ion exchanger
In principle, a differentiation is made between
three operating modes:
„Timer-controlled, working according to
set times
„Amount-controlled, working according to
set delivery amounts
„Quality-controlled, continuously monitoring
the quality of the feedwater
These systems can be designed as single or
duplex systems. Single systems are designed
for intermittent operation, i.e. no softened
water is available during the regeneration
phase (several hours). Double-pendulum
softening systems are compulsory for
continuous operation.
Viessmann supplies this double-pendulum
softening system in different output sizes. The
softening module comprises a fully assembled
system with two columns of ion exchangers, a
salt solvent and the control unit. It can be used
without further installation work (Fig. C.5.1-1).
The softened water output between
two regenerations is specified during
commissioning and is derived from the system
size and the hardness of the untreated water.
The system operates fully automatically and
must only be replenished with rock salt to
achieve regeneration.
One exchanger is always available as there are
two ion exchanger columns. At any time, the
second column is either being regenerated or
on standby.
58/59
Decarbonisation:
if hardeners (Ca2+ + Mg2+) are present along
with hydrogen carbonate (HCO3-), also
referred to as m-value or alkalinity, the
(Ca2+ + Mg2+) content corresponding to the
hydrogen carbonate content can be removed
by means of a slightly acidic cation exchanger.
The released CO2 is expelled via the deaerator.
The total salt content is therefore reduced by
the amount of carbon hardness (HCO3-).
For a boiler feedwater treatment system,
the remaining hardeners (permanent
hardness) must be removed by means of
neutral exchange (softeners, very acidic ion
exchangers in Na form).
C.5.2
Osmosis systems
In recent years, osmosis systems have been
used increasingly for water desalination
(Fig. C.5.2-1). Osmosis is a physical process
that functions without chemicals, and is
therefore very environmentally friendly. The
yield of desalinated water (permeate) is
approx. 80 % of the water employed.
During osmosis, the untreated water is
forced through a membrane with a pressure
of approx. 30 bar. The pores of the semipermeable membrane allow the water
molecules to pass through (diffusion); the
solute salt remains on the entry side and is
extracted from the system.
It should be noted that the untreated water
must not contain any solids prior to entering
the osmosis system, and that the hardeners
are stabilised prior to entry (using fine filters
and dosing).
Solids would block the membrane
pores, leading to a rapid reduction in
system performance.
Osmosis systems should be operated as
continually as possible and are therefore
usually equipped with a buffer tank for
the permeate.
Fig. C.5.2–1
Osmosis system
C.5 Water treatment
Fig. C.5.3.1–1 TWT
C.5.3 Thermal water treatment (TWT)
With steam boilers, these compounds result
in dreaded pitting corrosion. Localised erosion
can occur incredibly quickly, particularly in the
area of the feedwater inlet. It is therefore vital
to extract the dissolved gases from the boiler
feedwater. One proven means to this end is
thermal feedwater deaeration.
Water can only store a limited amount of
gas. The storage capacity can be calculated
according to Henry's law (English chemist,
1775 – 1836), subject to partial pressure of the
gas and the water temperature. For example,
water contains approx. 8 mg O2/kg at a
temperature of 25 °C.
Total thermal deaeration system
Fig. C.5.3.1–2 TWT
The solubility of gases reduces as the water
temperature rises (see Fig. C.5.3.1-3 and
C.5.3.1-4). In extreme cases, i.e. when water
evaporates (the situation in a steam boiler),
all dissolved gases are released. The gases
frequently form other compounds. The free
oxygen can, for example, combine with the
ferrous steel of the boiler.
Total thermal deaeration system
Fig. C.5.3.1–3
Solubility of oxygen
16
14
12
10
8
O2 [mg/l]
6
4
2
0
0
20
Temperature [°C]
40
60
80
100
Solubility of oxygen depending on temperature at 1 bar in pure water
Fig. C.5.3.1–4
Solubility of carbon dioxide
3500
3000
2500
CO2 [mg/l]
2000
1500
1000
500
0
0
20
Temperature [°C]
40
Solubility of carbon dioxide depending on temperature at 1 bar in pure water
60
80
100
60/61
Fig. C.5.3.1–1 Total deaeration system
Vapour outlet
Additional
water feed
Condensate feed
Deaerator
Heating steam
Feedwater tank
Feedwater
Source: Powerline
C.5.3.1 Total deaeration
Total thermal deaeration is the most effective
method for removing gases dissolved
in feedwater. In the deaerating system
(Fig. C.5.3.1-1), feedwater is freed from
practically all gases by heating it to close to
boiling point. Parallel to removing the dissolved
gases, the water is also held with low applied
steam pressure at a temperature of 105 °C
to prevent renewed absorption of gases. It
should be noted that, apart from fresh water,
condensate too can be fed into the system;
this must also be deaerated.
Total deaeration has proven to be the best
solution in the great majority of cases.
The term total deaeration always implies
deaerating with a slightly positive pressure
(approx. 0.1 to 0.3 bar / low pressure).
The term "low pressure" therefore describes a
process that is run at a pressure slightly above
ambient pressure. Operation with positive
pressure ensures that contact between
the feedwater and atmosphere and the
redissolution of gases is prevented.
The total deaeration system comprises the
deaerator and feedwater tank assemblies. The
deaerator is mounted directly on the feedwater
tank, in the form of a dome (Fig. C.5.3.2-2).
Depending on the requirements for feedwater
quality, different types of thermal deaerator
can be employed. Notes on the constitution of
boiler water can be found in Fig. C.5-1 and
C.5-2 (chapter C 5). Compliance with the
specified limits is a prerequisite for the reliable
and cost-effective operation of a boiler system.
An O2 content of 0.02 – 0.05 mg/litre must be
maintained in the feedwater for shell boilers,
subject to boiler pressure.
C.5 Water treatment
C.5.3.2
Partial deaeration
The term partial deaeration refers to deaeration
undertaken at atmospheric pressure. Partial
deaerators are permanently connected to the
atmosphere via the ventilation line. Partial
deaeration is the simplest form of thermal
feedwater treatment.
The somewhat greater demand for oxygen
binders associated with these deaerators (see
chapter C.5.1 Chemical water treatment) is
deemed acceptable.
The partial deaerator (Fig. C.5.3.2-1) is
equipped with components for the distribution
and irrigation of the supplied freshwater and
the returning condensate. Heating steam for
expelling gases is supplied via a lance that
Fig. C.5.3.2–1
is installed centrally in the lower part of the
tank. The steam supply is, in its simplest
form, matched by a mechanical thermostat
and regulated to 90 °C. Fresh water is topped
up via an electric level controller. Partial
deaerators are predominantly used in boiler
systems with low output and pressure.
Partial deaeration system
Additional water feed
Condensate
feed
Air vent valve
Heating steam
Overflow
Feedwater
Source: Powerline
Fig. C.5.3.2–2
Partial deaeration system
62/63
The most commonly used form of deaerator is
the irrigation deaerator
In the irrigation deaerator, the condensate fed
back into the system and the added freshwater
are finely distributed over so-called cups and
brought together with the heating steam in
stages by the irrigation process (hence the
term "irrigation deaerator"). Water heating and
the expulsion of released gases also takes
place in stages.
The development of this deaerator into an
irrigation deaerator with an integral re-boil
facility (two-stage deaeration) has proven to be
particularly effective.
Today, deaerators are made completely from
stainless steel, to prevent corrosion.
The feedwater tank is designed to hold an
adequate amount of boiler feedwater. The tank
is connected to the deaerator via a so-called
tank neck.
Fig. C.5.3.2–3 TWT with feedwater pumps
Feedwater tank with mounted irrigation deaerator
The feedwater tank is equipped with a
heating lance to receive and distribute the
heating steam.
The steam introduced in this way heats the
feedwater to 102 °C. The lance is fixed centrally
in the lower section of the tank. In the case of
single stage deaeration, the lance is sized for
the throughput of the entire heating steam. In
the case of two-stage deaeration, the lance is
designed to keep the stored water hot.
In both versions, partial cooling of the
feedwater and the resulting redissolution of
gases is prevented.
The feedwater tank (Fig. C.5.3.2-3) is equipped
with valves for regulating the heating steam,
the filling level and for safety as well as
displays required for operation and monitoring.
C.6 Condensate management / treatment
Condensate management / treatment
Depending on the technical processes in the area of steam application, the steam can
be introduced directly into the product or the process concerned. In such cases, no
condensate is returned.
In the majority of applications, however, steam
transfers its heat via a heating surface, where
it condenses. The condensate is then returned
to the boiler system for further utilisation.
From a technical viewpoint, there are two
different types of condensate return.
„C 6.1 Open vented systems
„C 6.2 Sealed unvented systems
64/65
C.6.1
Low pressure condensate
In 90 % of all steam boiler systems, the
condensate is returned via open condensate
tanks. At operating temperatures in excess of
100 °C, this involves re-evaporation. Approx. 5
to 15 % of the weight of condensate turns into
re-evaporation steam, subject to pressure level.
Naturally, apart from energy losses, water
losses also occur that must be made good
by topping up with fresh water that has been
subjected to appropriate water treatment.
Aside from these losses, the condensate
in open systems also absorbs oxygen that
can then lead to oxygen corrosion in the
condensate system.
Fig. C.6.1–1
Condensate tank
C.6.2
High pressure condensate
Fig. C.6.2–1 Tank
In the case of high pressure condensate
systems, the condensate is returned in a
sealed system (approx. 10 % of steam boiler
applications). Under these conditions, no
losses can occur due to re-evaporation. At the
same time, infiltration of air-borne oxygen into
the condensate system is also prevented.
Such systems are appropriate if they
operate at a pressure of at least 5 bar and a
permanently high level of condensate return is
present. It should be noted that all pipework,
valves, pumps and containers must be suitable
for this pressure.
The containers (e.g. condensate collector
(Fig. C.6.2-1), feedwater tank) are pressure
vessels that must be monitored in accordance
with the PED and are therefore subject
to monitoring by an approved monitoring
body (ZÜS).
When planning new systems and also in the
energy assessment of existing systems, a
decision must be made as to which system to
use. Substantial operating costs can be saved
through optimum condensate management
and utilisation of the re-evaporation steam.
Condensate collector tank
C.6 Condensate management / treatment
C.6.3
Condensate treatment
Due to the technical processes and on account
of corrosion products, condensate may be
contaminated with foreign bodies. Water
quality requirements must be met, however,
since the condensate is re-used as feedwater.
Typical condensate contaminants that may
occur are:
„Mechanical contaminants (corrosion
products)
„Onset of hardness (DHW or service water
leakage in heat exchangers)
„Ingress of acids and lyes (unintentional
mixing during the heating of acid or
lye baths)
„Oil and grease (food processing industry,
oil preheaters)
Subject to the degree of contamination,
provision is made for the necessary water
treatment processes, such as filtration,
degreasing, softening and complete
desalination. It should be noted during
the design of such systems that the boiler
regulations specify the provision of automatic
analysis devices to monitor the condensate
in the case of operation without constant
supervision (see chapter D.4.5).
When contaminants are detected in the
condensate, the contaminated condensate
must be removed from the water-steam cycle.
Fig. C.6.3–1
The sampling points must always be located
in the condensate inlet, upstream of the
collector tank, to prevent contaminated
condensate from flowing into the tank. The
condensate must be removed by means of
three-way valves.
Regarding the contaminants, a distinction
is made between products that increase
conductivity, such as acids, lyes, untreated
water, etc., and substances such as
oil, grease, whey, etc. Substances that
increase conductivity are monitored with a
conductivity capturing system; oil, grease
etc. are monitored with photo-optical
measuring systems, so-called oil and turbidity
detectors. Both systems, along with hardness
measurement, are available today in tested
and WÜ 100-approved versions.
With 72 h unattended operation (BosB 72h),
condensate monitoring for oil turbidity must be
implemented with redundancy. In this case, a
second sensor is installed downstream of the
3-way valve. Reason: this also monitors the
function of the 3-way valve. Please note: on
connection of the second monitoring device,
burner and pumps must undergo a safety
shutdown in order not to contaminate the
downstream containers up to and including
the boiler. The 3-way valve is preferably a
pneumatic valve. Pneumatic valves assume
a safety position in the event of a fault (e.g.
membrane defect).
Condensate monitoring
Condensate inflow
3-way valve
1st sensor
2nd sensor
Source: Gestra
66/67
C.6.4
Sampling cooler
Fig. C.6.4–1
Sampling cooler
The chemically and thermally treated
feedwater is tested by means of sampling and
corrected as necessary by dosing chemicals.
In the case of 24 h unattended operation
(BosB 24h), the boiler feedwater must be
analysed once a day and every 3 days for
BosB 72h.
The boiler (feed) water is cooled down and
relieved of pressure by means of a sampling
cooler (Fig. C.6.4-1). It can subsequently be
analysed without risk. The process described
above is tried and tested plant technology.
However, when monitoring and operating this
technology, faults can occur from time to time.
For that reason, Viessmann has developed
an analytical concept to reduce the potential
damage caused by the chemical composition
of water as far as possible.
Furthermore, this method of water analysis
enables a more economic operation of
steam systems.
Depending on the requirements made of
the system, the analysis technology can be
extended or reduced and is fitted, where
necessary, in an analysis rack.
Fig. C.6.4–2 Water analysis
C.6 Condensate management / treatment
Fig. C.6.4–4
Integration method
5
Steam to the
consumer
9
13
Top-up
water
11
2
HK
1
Bypass
Feedwater
control
valve
Blow-down
valve
Raw water
14
3
PK
12
O2
pH
16
4
O2 pH
7
6
Cooling water
Mixing cooler
8
1. Steam boiler with combustion system
2. Thermal water treatment
3. Boiler feed pump
4. Softening system
5. Chimney
6. T.D.S. expander
7. Mixing cooler
8. Cooler tank or drainage
9. Boiler system control panel
10. Condensate tank
11. Hardness check
12. O2 and pH test
13. Higher-ranking control panel with
PLC for transferring data
14. Sample cooler for analysis
15. Conductivity test
16. Dosing of corrective chemicals
17. Oil turbidity test
ÖT
LFS
17
15
10
Condensate
from the consumer
68/69
C.6.5
Dosing corrective chemicals
To maintain the alkaline level of the feedwater,
to bind the residual hardness and to bind the
residual oxygen, corrective chemicals are
added to the feedwater downstream of the ion
exchange or osmosis.
For this purpose, a number of products are
offered by water treatment companies. The
water treatment companies should always be
consulted regarding the conditions of use.
Viessmann supplies complete dosing stations,
usually in combination with the thermal water
treatment system.
Fig. C.6.5–1
Dosing station
C.7 Pumps
Pumps
Boiler feed pumps supply the steam boiler
with water in accordance with the required steam output.
A differentiation is made between intermittent
and continuous level control. The relevant
control variable for this purpose is the filling
level of the steam boiler.
70/71
C.7.1
Feedwater pumps & control
Fig. C.7.1.1–1 Version 1
Chimney
Steam to the
consumer
Feed facilities (generally 2 x 100 % pumps)
must ensure reliable coverage of "water
losses" arising due to steam being drawn off
and desalination or blow-down, and make
them up respectively. Stringent requirements
in accordance with TRD 401, 402 and 802
are made of their design (delivery head and
amount) and availability.
C.7.1.1
Control panel
Top-up
water
Steam boiler with
combustion equipment
Thermal water treatment
(full deaeration)
Chemical
water
treatment
(softening)
Boiler
feedwater
pump
Blow-down
valve
Raw
water
Intermittent level control
Cooling water
The water level is regulated between two
adjustable switching points, i.e. "pump ON"
and "pump OFF". The signal of the level
electrode affects the pump.
T.D.S.
expander
Mixing cooler
Drainage
Condensate container
Condensate from the consumer
This can be regarded as the simplest solution
for steam boilers without an economiser
and output up to 3 t/h. This version is not
recommended for steam output above 3 t/h or
when using an economiser.
C.7.1.2
Continuous level control by means
of feedwater control valve and
optional bypass
Fig. C.7.1.2–1 Version 2
Chimney
Steam to
the consumer
Control panel
The control aims to maintain a near constant
level in the boiler that corresponds to a
specified set value. The actual value is
continuously monitored by a level probe and
compared with the set value in a controller.
Opening and closing the feedwater control
valve regulates the level to the required set
value in the case of load fluctuations.
A certain amount is returned to the feedwater
tank via an adjustable minimum volume
line. This so-called bypass line is designed
to protect the pump from falling below a
specified minimum pump rate.
Top-up
water
Steam boiler with
combustion equipment
Thermal water treatment
(full deaeration)
Chemical
water
treatment
(softening)
Bypass
Blow-down
valve
Feedwater
control
valve
Cooling water
T.D.S.
expander
Mixing cooler
Drainage
Boiler
feedwater
pump
Condensate container
Condensate from the consumer
Raw
water
C.7 Pumps
C.7.1.3
Continuous level control by means
of feedwater valve with spillback
This is an alternative to Version 2, whereby
both valves (feedwater control valve and
bypass valve) are combined into a single valve.
As soon as the main flow falls below a certain
flow rate, the spillback non-return valve
(bypass) opens wide enough so that the
required minimum pump rate can always be
drawn off.
Fig. C.7.1.3–3 Version 3
Steam to the
consumer
Chimney
Control panel
Top-up
water
Bypass
Steam boiler with
combustion equipment
Thermal water treatment
(full deaeration)
Chemical
water
treatment
(softening)
Feed-water
control valve
with spill back
Blow-down
valve
Cooling water
T.D.S.
expander
Mixing cooler
Drainage
Fig. C.7.1.2–2
Source: RTK
Control valve with bypass
Boiler
feedwater
pump
Condensate container
Condensate from the consumer
Raw
water
72/73
C.7.1.4
Continuous level control by means
of variable speed pump control
The control aims to maintain a near constant
level in the boiler that corresponds to a
specified set value. In the event of load
fluctuations, continuously variable speed
control (here with a mounted inverter) is used
to adjust the pump rate to match the changing
demand until the set level has been achieved.
This demand-dependent speed optimisation
saves electric power. It can also save the
installation of control valves upstream of
the boiler.
Fig. C.7.1.4–4 Version 4
6WHDPWR
WKHFRQVXPHU
&RQWUROSDQHO
7RSXS
ZDWHU
6WHDPERLOHUZLWK
FRPEXVWLRQHTXLSPHQW
7KHUPDOZDWHUWUHDWPHQW
IXOOGHDHUDWLRQ
&KHPLFDO
ZDWHU
WUHDWPHQW
VRIWHQLQJ
&RROLQJZDWHU
7'6
H[SDQGHU
0L[LQJFRROHU
'UDLQDJH
5DZ
ZDWHU
&RQGHQVDWHFRQWDLQHU
&RQGHQVDWHIURPWKHFRQVXPHU
The use of a variable
speed pump is advisable
if the control ratio of
the pump is ≥ 1:4 and
the control range of
the feedwater pump
is at least the same
magnitude as the control
range of the boilerburner unit.
Quick control circuits
(3-component control)
Additional benefits of
a variable speed pump
(inverter pump):
„Soft start, surge
free operation on
switching the pump
ON and OFF
„NPSH The NPSH
value of a centrifugal
pump drops with
lower speeds. This
reduces the risk of
cavitation
Condensate pumps
Condensate pumps (generally 2 x 100 %
pumps) must be capable of transporting the
amount of condensate accumulating on the
customer side and in the system according
to requirements (either intermittently or
continuously depending on demand from
the steam boiler system). The necessary
delivery heads depend on the back pressure
in the tank, pressure-side pipework losses
and the density (temperature-dependent) of
the medium.
%RLOHU
IHHGZDWHU
SXPS
Note
In the case of quick control circuits where
level control is too slow, signal values from the
steam consumers can be hooked up to the
control valve in order to adjust the required
feedwater volume to the rapidly increasing
steam demand.
It is also conceivable to construct a mass
balance around the boiler to facilitate rapid
reaction to load changes. In this case, the flow
rate will be captured both on the water and on
the steam side, with balancing and switching
of signals to the control valve. The amount of
steam is the control variable here.
C.7.2
)8
%ORZGRZQ
YDOYH
Please note: The control range of the
feedwater pump should be at least as wide as
the control range of the boiler-burner unit.
C.7.1.5
&KLPQH\
˂H =
˂p
pxg
˂p in bar or
p in
kg
m3
g:9.81 m/s2
N
m2
C.8 Thermal equipment
System-dependent thermal equipment
Thermal equipment guarantees the correct function of a steam boiler system.
The components described here are necessary
integral parts of a steam boiler system.
Depending on the respective system concept,
additional equipment that is not described here
may be required.
74/75
C.8.1
Mixing cooler
The mixing cooler is designed to accept all
pressurised and hot waste water that occurs in
the boiler system.
This water is expanded to atmospheric
pressure in the mixing cooler. The mixing
cooler vents to atmosphere.
By adding cooling water from the untreated
water network via an inbuilt lance, waste
water is cooled to a drain temperature of
30 to 35 °C.
Fig. C.8.1–1
Mixing cooler
C.8.3
Exhaust vapour condenser
The exhaust vapour condenser (generally
a steam/water plate heat exchanger) is
designed to condense the low pressure steam
vapour (steam) from the deaerator in the
TWT system.
The resulting condensation heat is returned
to the system as recovered heat via added
amounts of feedwater and/or condensate.
Implementation of an exhaust vapour
condenser depends on the results of a costbenefit analysis.
Fig. C.8.3–1
Exhaust vapour condenser
Thermal water treatment
(full deaeration)
C.8.2 T.D.S. expander and lye cooler
Fig. C.8.3–2 Exhaust vapour condenser, schematic representation
The T.D.S. expander is designed to accept the
boiler desalination fluid and to expand it to a
pressure level of 0.5 bar.
The expansion steam is utilised as heating
steam in the deaeration system (TWT).
The residual lye is cooled down using a lye
cooler before it is routed to the mixing cooler.
Conversely, the softened water is preheated in
this process.
Above the roof
Water vapour condenser
Cooling water
Feedwater
and/or condensate
Water vapour
condensate
Fig. C.8.2–1 T.D.S. expander with lye cooler
Deaerator
C.8 Thermal equipment
Fig. C.8.4–1
Feedwater cooler
C.8.4
Steam to the
consumer
Control panel
Top-up
water
Steam boiler with
combustion equipment
Thermal water treatment
(total deaeration)
Feedwater
control
valve
Blow-down
valve
Boiler
feedwater
pump
Chemical
water
treatment
(softening)
The feedwater cooler (generally a steam/water
plate heat exchanger) is designed to lower the
feedwater temperature (generally to ≤ 100 °C)
upstream of the chosen and implemented
economisers (ECO).
By reducing the described ECO feedwater inlet
temperature, the additional latent heat present
in the flue gas can be removed and the boiler
efficiency level increased.
To take advantage of this, the required
additional feedwater (softened water) from
the chemical water treatment system (CWT)
should be used as the "coolant" here upstream
of the feedwater tank inlet. Implementation of
a feedwater cooler depends on the results of a
cost-benefit analysis.
Raw
water
C.8.5
Fig. C.8.5–1
Feedwater cooler
Feedwater preheater
High pressure condensate feedwater preheater
Steam
Steam
Feedwater
Condensate
Where an economiser is used in combination
with such fuels as heavy fuel oil, masut etc.,
it is essential that the temperature does
not fall below the dew point in the boiler/
economiser. To ensure that this is prevented
under all operating conditions, the feedwater
is heated upstream of the inlet into the
economiser to 130 °C using a heat exchanger.
The heating in this case can be provided by
an internal indirect coil in the boiler or another
heat source, such as steam. In that case
in conjunction with a steam/water tubular
heat exchanger. The type of heating must be
selected on a project-specific basis.
A reduction in efficiency is consciously
accepted in order to guarantee the durability of
the economiser.
76/77
Fig. C.8.5–2
Steam boiler system
Pfizer Animal Health
Louvain-La-Neuve, Belgium
2 x 3.2 t/h
C.9 Pipework system
Pipework system
All pipework, fittings, steam distributors and dewatering lines required for transportation
of the media must also be considered as part of the boiler house components.
Essentially, the pipework system consists of
the main pipes ≥DN 25 (see chapter D 8) for
the following media:
„Steam and condensate
„Exhaust vapours and evaporate
„Feedwater and raw water
„Waste water
„Fuel oil and gas
„Flue gas
78/79
Fig. C.9–1
Fig. C.9.1–2
Main steam pipe
Steam distributor
C.10 Flue system
Ahlstrom Malmédy, Belgium
14 t/h, 13 bar
Flue system
Flue systems are designed for the controlled discharge of flue gases. Apart from the
chimney, they include all the connection lines between the heat/steam generators as
well as all the necessary built-in parts, such as silencers and flue gas dampers.
The flue system to be designed and
implemented for a steam system essentially
consists of the following:
„Flue pipe together with all required built-in
parts (flue gas damper, compensator and,
if necessary, a flue gas silencer)
„Emission test system with operating
platform, if necessary; test and
calibration ports
„Cleaning and access apertures
„Chimney system with neutralising
system, if required, for the arising flue
gas condensate
In Germany, the fundamental principles of
design and implementation are the expected
total system combustion output together
with the applicable specifications according
to the Technical Guide for Air Conservation
(TA-Luft) and/or the applicable German
Immissions Act (BImSchV) and the applicable
regional legislation.
The preferred location for test points is in
the chimney, taking into consideration any
necessary inlet and/or outlet paths. Installation
in the "straight" flue is also conceivable.
80/81
Fig. C.10–2
Steam system flue gas silencer
Steam system flue gas silencer
(2x 18t/h, 20 bar)
Fig. C.10–1
Flue system (Dingolfing)
Note
The required scope
of emission test
equipment to be installed
is determined on a
binding basis during the
approval process by the
licensing authority.
It must be assumed
that measurements are
required, if applicable, for:
„NOX
„SO2
„CO
dust and/or soot value.
C.11 Internal system demand
Internal system demand
This section considers the internal system energy demand.
In order to generate fresh steam, steam boiler
systems have their own internal demand
for power in the form of steam, power,
fuel and a small proportion of chemicals for
water treatment.
82/83
C.11.1
Internal power demand
The internal power demand of a steam
boiler system is essentially determined by
the electrical output of all drive units of the
individual main components.
The principle main consumers are:
„Combustion air fan
„Any existing flue gas recirculation fan
„Boiler feedwater pumps
„Condensate pumps
„Oil pumps
„Rotary cup atomiser motor (if installed)
„Valve servomotors for such fittings (if
installed) as: flue gas damper(s), ECO bypass
damper(s), main steam shut-off valve(s),
mixing and/or branching valve(s) etc.
„MSR control systems
„System lighting and emergency lighting for
the boiler room
Note
For the purpose of minimising the internal
power demand, electric drive units for pumps,
compressors and fans are often equipped with
inverters. During the engineering process, the
system operational regime is an important
condition for the use of inverters (cost/benefit,
see also chapters D 3.1 and D 6).
C.11.2
Internal thermal power demand
The following must be assessed in
determining the internal thermal demand:
„Heating steam for TWT = as a function
of condensate return losses, desalination
and blow-down losses as well as losses of
steam from the TWT and the mixing cooler
The losses listed here must be made good by
additional feedwater from the water treatment
system. The system internal thermal power
demand rises in line with the increase in the
amount of additional feedwater to be heated
in the TWT.
Demand-dependent system operating
conditions must always be considered in
determining the internal demand of a system
according to chapter C 11.
The necessary approach, layout and
calculations are described in greater detail in
chapter D 10.
C.12 Insulation
Insulation of pipes, tanks etc.
Insulation not only serves to protect against heat / energy loss and to protect against
burning / scalding, but also serves to stabilise the system conditions.
If, for example, steam lines were not insulated,
then excess condensation would form in the
pipes, leading to unstable system conditions.
Since all the tanks, containers, and valves in a
steam boiler system are joined together with
pipes, a corresponding number of pipes must
be insulated subject to operational parameters.
84/85
C.12.1 Thermal insulation
(see Appendix A2)
C.12.2
Pipework, valves, devices and tanks that
are heated up must be protected against
heat losses and/or contact by means of an
externally applied insulation shell.
Pipework, valves, devices and tanks that are
cooled down must be insulated as required to
prevent the formation of condensate.
Subject to requirements, the preferred
insulation materials are:
„Multi-component foam shells and/or
„Foam glass shells
The preferred thermal insulation materials are:
„Mineral fibre mats (glass and rock wool)
„Plastic jackets
„Directly applied foaming plastics
„Plastic shells for valves and pipe structures
Protection against the formation
of condensate
The most important basis cited for designing
thermal insulation in this case is the VDI
Guideline 2055 and the ENEV.
The party responsible for system design
(system manufacturer, heating engineer)
must assume responsibility for the complete
technical processing and engineering of the
respective insulation. Consequently, the notes
in chapter D 8.3.4 and Appendix (A2) must only
(see also chapter D.8.3.4)
be regarded as "initial" design aids.
C.13 Control system
SSAO Servolux, Lithuania,
3x Vitomax 200-HS
Control system
4 t/h; 13 bar
Ideally, control units are switched by a programmable logic
controller (PLC).
A central, full graphic colour display (touch
panel) (Fig. C.13-1) is used for boiler operation
and setting its parameters.
Fig. C.13–1
PLC touch panel
This display also shows all functions with the
associated operating conditions, as well as
all set and actual values. The hours run by the
burner and the feedwater pumps are recorded
by the PLC.
In the case of dual-fuel burners, the hours run
and number of starts made by each individual
burner are recorded separately.
PLC touch panel, Vitocontrol control panel
86/87
All fault messages are recorded and reported
with date and time of their occurrence.
C.13.1 Main functions
C.13.1.1 Burner output control
The fault messages are also stored as a
"history" so that the occurrence of faults,
their acknowledgement and their removal is
documented.
The boiler pressure is measured by a probe
and transferred to the PLC in the form of
an analogue signal. The PLC regulates the
pressure to a set value specified by the
operator or a higher-ranking controller.
From the deviation between the set and
the actual pressure, the output controller
calculates the modulation level of the burner
or the respective burner stage, subject to
configuration.
The control system (Fig. C.13-2) contains all
components required for activation of the
boiler-specific control equipment in steam
boiler systems.
C.13.1.2 Water level control
Fig. C.13–2 Vitocontrol control panel
The level control of the steam boiler stored in
the PLC can be implemented in the form of a
two-point control by starting or stopping the
feedwater pumps or as a continuous control
using a feedwater valve.
Starting and stopping the feedwater pump(s)
or the additional regulation of the feedwater
valve supplies the required volume of
feedwater to the boiler for maintaining the
set water level inside the boiler. When two
feedwater pumps are installed, the pumps are
switched alternately and also in the event of a
fault in one of the pumps.
C.13.1.3
Vitocontrol control panel
Conductivity boiler water
T.D.S. control
As an option, the "desalination" function is
implemented by means of continuous control
in the PLC. The water conductivity is captured
by a probe and transferred to the PLC in the
form of an analogue signal. The set value
"salt content" and the control parameters are
defaulted by the programming unit. When the
salt content is too high, the T.D.S. valve opens
to drain off the saline water.
C.13.1.4
Blow-down control
As an option, the blow-down valve can be
activated by the PLC subject to stored values
for the interval between two blow-down
events and the duration of valve activation.
C.13.1.5 Additional functions
Activation of a flue gas and/or bypass damper
as well as switching to a second set value
(pressure) are also integrated into the PLC.
Note
Necessary extension in
conjunction (respective
consideration) with
all ancillary systems
according to RI diagram
in Appendix (A1).
The control panel
also contains the
components required
for fully automatic
boiler operation without
supervision over 24
or 72 hours according
to TRD 604. These
include all the "specially
designed" components
required for operation of
a steam boiler system.
Note
A special design
means an electrical or
mechanical part of any
device that automatically
implements regular
tests (e.g. for electrode
water level meters, the
insulation resistance
of which is monitored,
automatic function tests
in immersion devices,
blowing through of
connecting lines in
external devices).
C.14 Rules and regulations
Rules and regulations
All the cited components are considered in the evaluation of a steam
boiler system by the designated body, ZÜS (approved monitoring body)
or monitoring organisation.
In the final analysis, a steam boiler system
designed according to technical rules is
the basis for releasing the system for
commissioning.
pressure equipment in Member States" (PED)
came into force on 29 May 1997, granting a
transition period of five years for member
states.
C.14.1
The PED applies to all steam boilers with a
maximum permissible pressure in excess of
0.5 bar or an operating temperature higher
than 110 °C and a volume in excess of 2 litres.
It should be noted with regard to the content
that the total volume of the steam boiler must
always be taken into account.
Legal framework
As early as 1985, there was a call for standard
technical rules to achieve a pan-European single
market without trade barriers. However, different
regulations concerning the manufacture of
pressure equipment, and consequently steam
boilers, still applied to the member states of the
European Union until 1997.
The "Directive 97/23/EC of the European
Parliament and Council dated 29 May 1997 on
the assimilation of the legal requirements for
This Directive does not apply to steam boilers
with an operating pressure lower than 0.5 bar
and an operating temperature lower than
110 °C. Rules such as the EC Gas Appliances
Directive 2009/142/EC apply to these systems.
88/89
Fig. C.14.1–1
PED diagram
PS
[bar]
1000
100
PS = 32
32
25
Appendix II of the PED divides combustion
pressure equipment (steam boilers) into
different categories (Fig. C.14.1-1).
The possible module categories according to
the PED are derived from categories III and IV.
The module categories regulate which tests
the manufacturer can carry out and which
tests must be performed by an independent
testing body ("designated body" according to
the PED).
High pressure steam boilers from the
Vitomax 200-HS and Pyroflex FSB / FSR series
as well as the low pressure steam boiler
Vitomax 200-LS fall into category IV of the
diagram on account of the following formula:
pressure x capacity.
Only the Vitoplex 100-LS boiler series
(Fig. C.14.1-2) (steam boilers with a
permissible operating pressure of 1 bar) with a
capacity of > 1000 litres fall into category III.
Category IV high pressure steam boilers
are tested preferably in accordance with
module G. This means that a "designated body"
appointed by the manufacturer carries out all
boiler tests.
These tests comprise testing the draft design
(checking the pressure part calculation and
design features in accordance with standard
specifications), checking the production
processes, monitoring the build, strength test
(pressure test) and a final inspection.
The body commissioned with carrying out
the tests issues a Declaration of Conformity
following a successfully completed final
inspection in accordance with module G.
PS
10
V
PS
=
50
V
=
PS
20
0
V
=
30
00
Diagram of the PED, modified
3
1
0.5
I
II
III
V = 1000
The PED regulates all processes up to market
launch of the pressure appliance. Apart from
the pressure appliance itself, all equipment
components with safety functions and all
pressurised equipment parts fall into the
scope of this Directive.
according to the EHI (Association
IV
PS = 0.5
of the European Heating Industry,
guideline regarding the application
0.1
1
2
6.25
10
100
400 1000
10000 V [liters]
Note
Selling and commissioning
„Selling is the first provision of a product,
against payment or free of charge, in the
single market for distribution or use within
the territory of the European Union. With
the selling of a product, the inherent risk is
transferred from the manufacturer to the
operator. The operator's risk assessment
must have been submitted
„Commissioning takes place with the first
use by the end user within the territory of
the European Union. The necessity within
the scope of market supervision to ensure
that the products, on commissioning,
comply with the provisions of the directive
is however limited
„If a product is being sold in the single
market and commissioned for the first
time, it must comply with the applicable
directives drawn up according to the
new concept. The member states of the
EU are obliged not to prohibit, restrict
or hinder the sale or commissioning of
products that comply with the applicable
directives drafted in accordance with
the new concept. Furthermore, they
must take all the measures necessary
for ensuring that products can only be
traded and commissioned if they do not
represent any risk to the safety or health
of persons or other interests affected by
the applicable directives, insofar as the
products are correctly built, installed,
maintained and used in accordance with
their intended purpose
of the Pressure Equipment Directive
97/23/EC)
Fig. C.14.1–2 Vitoplex 100 LS
Low pressure steam boilers,
260 to 2200 kg/h
C.14 Rules and regulations
Fig. C.14.1–3
Declaration of Conformity for high pressure steam boilers (example)
By the manufacturer affixing the CE symbol
and issuing the Declaration of Conformity, as
well as providing verification of tests having
been carried out in accordance with the
module derived from Diagram 5, the boiler can
be sold without any trade barriers anywhere in
the territory of the EU member states.
EU member states must assume that the
boiler satisfies all provisions stipulated in the
applicable directives, for example the PED
(assumption of conformity).
For countries outside the EU that do not
recognise the PED, separate arrangements
need to be made between the manufacturer
and the supervisory organisation of the
country concerned.
The manufacturer states in the Declaration of
Conformity (Fig. C.14.1-3) that the steam boiler
meets the applicable requirements according
to the PED and other relevant directives. To
indicate that fulfilment of these requirements,
the manufacturer affixes the CE designation to
the boiler.
Standard production boilers can be manufactured
according to module B (EC type testing).
In the case of this module, the manufacturers
themselves carry out the tests on each
standard production boiler. This is conditional
on the manufacturer operating an approved
quality assurance system for the manufacture,
final inspection and all inspections/tests
associated with the manufacture, subject to
monitoring by a designated body.
Module D describes that the manufacturer
has an approved quality assurance system in
place for the manufacture, final acceptance
and inspection/testing of boilers. This includes
preparation of the technical documentation.
1
see note on page 89
With implementation of the Product Safety
Directive 2001/95/EC, a law has been created
from the core provisions of the German
Equipment Safety Act (GSG) and the Product
Safety Act (PordSG) for reforming the safety
of technical equipment and consumer
products. The German law concerning
technical equipment and consumer products
is designated as the Equipment and Product
Safety Act (GPSG), dated 6 January 2004
and effective from 1 May 2004. The GPSG
serves the purpose of implementing Directive
97/23/EC with regard to manufacture and
operation. The manufacture and therefore
the quality requirements are governed by the
14th regulation of the Equipment and Product
Safety Act (Pressure Vessel Ordinance 14.GPSGV dated 17 June 1998). This applies
to the sale1 of new pressure equipment and
assemblies with a maximum permissible
pressure of in excess of 0.5 bar.
Operational issues are governed by the
regulations concerning safety and health
protection in the provision of equipment and
its use in the work environment, concerning
safety in the operation of systems requiring
supervision and those concerning organisation
of operational industrial safety. The so-called
BetrSichV ([German] Health & Safety at
Work Act), dated 27 September 2002, applies
to the provision of equipment by the employer
and the use of equipment by employees
at work.
90/91
Fig. C.14.1–4 Laws, regulations and technical rules
Legal basis for the installation of a
steam boiler system using Germany
as an example
Section 2 of the BetrSichV, "Common Rules
for Tools", contains the assessment of hazards
according to the German Work Safety Act
(ArbSchG). Among other aspects, Section 3 of
the BetrSichV, "Special Provisions for Systems
Requiring Supervision", covers:
„Operation paragraph 12
„Reservation of permission paragraph 13
„Testing prior to commissioning
paragraph 14
„Specification of inspection intervals
paragraph 15
Section 4 of the BetrSichV, "Common Rules,
Concluding Provisions", contains notes
regarding the Safety and Health Commission
paragraph 24. The Safety and Health
Commission (ABS) is the successor to the
German Steam Boiler Commission (DDA)
charged with the following tasks:
1. Determination of rules in accordance with
state-of-the-art technology
2. Determination of rules for meeting the
requirements of the Ordinance on Industrial
Safety and Health (BetrSichV)
3. Advising the Federal Ministry of Economics
and Labour (BMWA) in questions relating to
operational safety
The ABS prepares the technical regulations
for operational safety (TRBS). The TRBS
substantiate the Ordinance on Industrial Safety
and Health with regard to:
„Determination and evaluation of hazards
„Derivation of suitable measures – "in
the application of the measures cited
as examples, the operator can exercise
compliance with the provisions of the
Ordinance on Industrial Safety and Health."
TBS 1111 and 2141 are cited as examples, in
which the assessment of risks and evaluation
of safety are described along with the hazards
caused by steam and pressure.
Section 2 of TRBS 1111: "The employer
is responsible for conducting the risk
assessment and the operator for carrying out
the safety evaluation."
Section 2.1 "Operational parameters" of
TRBS 2141, Part 1: "Operational parameters
are specifications of process and material
parameters, e.g. pressure, temperature,
flow rate, filling level, abrasiveness and
corrosiveness. They result from the respective
process and represent the sum of the
operating modes foreseen by the employer
and/or operator."
D Component layout
%
(
'
'
%
10
$
+
4
3
5
&
9
0
6
1
&
&
8
,
&
2
*
7
.
&
&
)
Steam boiler system overview
1
2
3
4
5
6
7
8
9
10
Steam boiler
Control system (PLC)
Integral economiser
Total thermal deaeration system
T.D.S. expander with heat recovery
Mixing cooler
Chemical water treatment
Feedwater pumps
Dosing stations
Flue gas damper
A)
B)
C)
D)
E)
F)
G)
H)
I)
K)
M)
Steam to the consumer
Discharge pipe safety valve
Ventilation and drain line
Water vapour line
Condensate inlet
Fuel feed
Raw water inlet
Softened water
Feedwater
T.D.S. line
Blow-down line
92/93
D Component layout
This section provides relevant "simplified" information on the sizing and calculation of
the components listed in chapter C.
The basis for sizing the system is provided
by the "reference system" described in
Appendix (A1) along with the applicable
process-related economy and calculation
variables. Viessmann can supply you with socalled "enquiry checklists" for actual enquiries.
Please contact your Viessmann sales
representative for these checklists.
A correct response to the enquiry checklist is a
prerequisite for precise system sizing optimally
suited to the actual requirements.
Viessmann ensures you have all the help you
need in answering and preparing the enquiry
checklist with assistance provided by the
respective sales engineer.
93
D Component layout
96
Steam boiler selection
96
98
99
D.1
D.1.2
D.1.3
102
Product range
103
104
105
106
110
113
116
D.2.1
Steam boilers
D.2.2
Flame tube temperature monitoring (FTTM)
D.2.3
Economiser (ECO) operation
D.2.3.1 ECO output
D.2.3.3 Utilising condensing technology
D.2.3.4 Superheater (SH) operation
D.2.3.5 Pressure / heat maintenance - steam boiler
Steam boiler selection
Selection of the boiler pressure level
Waste heat boilers
D Component layout
118
Combustion systems
119
120
121
122
125
D.3.1 Variable-speed combustion air fan
D.3.2 O2 control
D.3.3 Amount of fuel / fuel demand
D.3.4 Combustion air, supply air ducts
D.3.5 Acoustic emissions from monoblock / duoblock burners
128
Water treatment
129
130
132
136
139
D.4.1 Total deaeration system
D.4.2 Partial deaeration system
D.4.3 Chemical water treatment system (CWT softening system)
D.4.4 Function description - reverse osmosis system (RO)
D.4.5 Water analysis, general explanations
142
Condensate management
143
144
D.5.1
D.5.2
150
Pumps
151
160
D.6.1
D.6.2
162
Sizing the thermal equipment
163
168
171
174
180
D.7.1 Mixing cooler
D.7.2 T.D.S. expander
D.7.3 Exhaust vapour condenser
D.7.4 Feedwater cooler
D.7.5 Sampling cooler
Function description of open vented condensate systems
Function description of sealed unvented condensate
systems
Feed pumps - criteria for design and operation
Condensate pumps - criteria for sizing and operation
94/95
182
Pipework
183
188
196
210
D.8.1
D.8.2
D.8.3
D.8.4
219
D.8.5
219
224
226
227
229
232
233
D.8.5.1
D.8.5.2
D.8.5.3
D.8.5.4
D.8.5.5
D.8.5.6
D.8.5.7
236
Flue system
237
239
240
242
D.9.1
D.9.2
D.9.3
D.9.4
244
Internal system demand
244
248
D.10.1
D.10.2
Pipework
Specifications - materials, welding work
Pipework calculations and sizing
Strength, expansion, support spans, clearances,
routing / mountings
Notes on design engineering of selected pipework
systems
Steam pipes / steam distributors
Condensate pipes and systems
Boiler lye and blow-down lines
Feedwater - softened water - drinking water
Exhaust vapour, waste steam and discharge pipes
Fuel lines
Waste water and floor drainage systems
Planning and design information for connection pieces
Sizing the flue system
Chimney connection and design
Common flue system, merging of flue gas flows
Internal electrical system demand
Internal thermal system demand
D.1 Steam boiler selection
Steam boiler with and without
waste heat utilisation
Steam boiler selection
Depending on individual customer requirements for pressure and/or the amount of steam,
as well as the quality of the fuel, a differentiation is made between the various boiler
types and designs.
The decision-making criteria are as follows:
D.1
1. Fuel
Biomass
Waste heat
Gas / oil
2. Pressure
</= 0.5 bar
> 0.5 bar
A choice is made here, depending on
requirements, between the:
„Vitomax 200-LS as a low pressure (NDE)
steam boiler, type M233, category IV
according to European Pressure Equipment
Directive DGRL 97/23/EC, in three output
sizes at a permissible operating pressure
of up to 1.0 bar
3. Output
Steam boiler selection
The working basis is the steam boiler datasheet
Fig. D.1–1 Vitomax 200-LS type M233
Amount of steama) (t/h)
2.9
3.5
5.0
Rated output (kW)
1900
2300
3300
96/97
and the:
„Vitomax 200-HS as a high pressure (HD)
steam boiler, type M73, category IV
according to European Pressure Equipment
Directive DGL 97/23/EC. This is available
in nine output sizes and different pressure
levels with a permissible operating
pressure of between 6 bar and 30 bar
Fig. D.1–2 Vitomax 200-HS type M73
Size
1
2
3
4
5
6
7
8
9
Steam outputc) (t/h)
0.5
0.7
1.0
1.3
1.65
2.0
2.5
3.2
4.0
Rated outputb) (MW)
0.325
0.455
0.65
0.845
1.1
1.3
1.65
2.1
2.6
and the:
„Vitomax 200-RS as a high pressure
steam boiler, category IV according to
European Pressure Equipment Directive
DGL 97/23/EC, for utilising waste heat
The working basis is the steam boiler
datasheet.
and the:
„Vitomax 200-HS as a high pressure (HD)
steam boiler, type M75, category IV
according to European Pressure Equipment
Directive DGL 97/23/EC. This is available
in 10 output sizes and different pressure
levels with a permissible operating
pressure of between 6 bar and 25 bar
The working basis is the steam boiler
datasheet.
Fig. D.1–3 Vitomax 200-HS type M75
Boiler size
1
2
3
4
5
6
7
8
9
A4)
Max. combustion output MW
Gas
3.8
4.5
5.3
6.4
7.5
9.0
10.5
12.7
15.7
18.2
HEL
3.8
4.5
5.3
6.4
7.5
9.0
10.4
12.2
14.0
14.0
EN 12953-3
Max. steam outputa) w/o ECO in t/h
Operating
pressure
5 bar
5.2
6.2
7.3
8.9
10.4
12.5
14.6
17.6
21.7
25.2
25 bar
5.0
5.9
7.0
8.5
9.9
11.9
13.9
16.9
20.8
24.2
Max. steam outputa) with ECO 200 in t/h
Operating
5 bar
5.5
6.5
7.7
9.3
10.9
13.1
15.3
18.5
22.9
26.6
pressure
25 bar
5.4
6.4
7.6
9.1
10.7
12.9
15.0
18.2
22.5
26.1
a)
With reference to feedwater
temperature = 102 °C and
Values between 5 and 25 bar can be interpolated
rated output without emission
requirements.
Please note!
When selecting an "appropriate" boiler steam output for the customer's needs, the "steam losses" to be
expected due to system-specific internal steam requirements (૷ FD/E) must also be considered.
That means: Amount of steamboiler = steam demandcustomer + amount of steam requirementsystem
A supplemente) of approximately 5 to 15 % can be assumed here in the initial analysis.
For example ==> amount of steamboiler = amount of steam requirementcustomer x 1.05 to 1.15
With reference to steam output
b)
at saturated steam pressure =
12 bar and feedwater temperature
= 102 °C.
c)
With reference to feedwater
temperature = 102 °C and
rated output.
d)
Steam output with gas combustion.
Alternative steam outputs
A "precise" calculation is made by the manufacturer with the formula specified in chapter D.10.2.
result from HEL and reduced
combustion output.
Supplement for heating freshwater
e)
requirement of 0 to 5 % and T.D.S.
rates ≤ 5 %. Intermediate sizes can
be interpolated here accordingly.
D.1 Steam boiler selection
Fig. D.1.2–1
Fig. D.1.2–2
Steam boiler limiter
D.1.2
Steam boiler limiter
Example 2
Example 1
13
bar
SiVresponse pressure
25
12
bar
SDB (burner locked out)
23.5
bar
bar
10.5
bar
DR (set value)
22
bar
SDB
MA
DA
SDB Safety pressure limiter
DA
Pressure sensor
MA Pressure gauge
MT Manostat bracket
MT
Selection of the boiler pressure level
Setting the manostats
Fig. D.1.2-2 illustrates an example of two
different pressure levels for our steam boilers.
The following approach is used to determine
the boiler pressure level (safety level).
The set value required by the customer is,
for example, 10 bar. This is the value that
must be available for production. A pressure
sensor is mounted on the manostat bracket
that transmits its signals to the controller
(pressure) stored in the PLC. The pressure
regulator is set, for example, to 10 bar and
regulates combustion depending on the steam
demand. For example, the pressure regulator
switches the burner off at 10.5 bar and back on
again at 9.5 bar. The start and stop values can
be selected freely. A safety pressure limiter
is located on the pressure side above the
pressure regulator, set, for example, to 12 bar.
In the event of pressure regulator failure, the
safety pressure limiter serves the purpose
of safeguarding the boiler from excessive
pressure and locks out the burner. Reactivation
can only be undertaken manually. Positioned
above this on the pressure side is the safety
valve that protects the boiler mechanically
against excessive pressure. The valve opens
to atmosphere at 13 bar. This means that a
boiler with 13 bar protection is required for
a required pressure of 10 bar. The equivalent
also applies at a required pressure of 22 bar.
A boiler protection of 25 bar would be required
in that case.
98/99
D.1.3 Waste heat boilers
Waste heat boilers utilise the waste heat
from industrial processes or, for example,
combined heat and power (CHP) modules
for the generation of heating water or steam.
Since the waste heat sources are manifold,
the steam boiler is designed specifically for
Fig. D.1.3.1–1
each individual case. Fig. D.1.3.1-1 indicates
the general conditions within which Viessmann
supplies waste heat boilers.
Depending on the number of flue gas sources
and their thermodynamic design, there are
single or multiple-pass waste heat boilers for
one or more flue gas sources.
Design parameters
Waste heat boiler w/o
Boiler with waste
additional combustion
heat utilisation
Proportion of output from
100 % with reference to the
10 to 30 % with reference to the
waste heat utilisation
total boiler output
total boiler output
Flue gas source
Suitable for flue gases from the following fuels: Fuel oil and natural gas. Other
fuels such as RME, animal fat, solid fuels and waste heat from contaminated
extract air available on request
Minimum flue gas volume from
5000 Nm3/h
1000 Nm3/h
the flue gas source
Maximum flue gas volume from
80,000 Nm3/h (from one or in total
10,000 Nm3/h (from one or in total
the flue gas source
from two flue gas sources)
from two flue gas sources)
Maximum permissible pressure load
25 bar
25 bar
1 or 2
1 or 2
on the water/steam side
Number of heating sources
Design versions
Plants that utilise waste heat are available in
numerous sizes and designs. The requirements
for waste heat boilers to be integrated into
these systems are correspondingly diverse.
Fig. D.1.3.1–2
Waste heat boiler, single-pass
In the simplest case, a separate waste heat
boiler is assigned to each flue gas source.
Single-pass waste heat boiler for generating steam
Flue gas inlet
Flue gas outlet
D.1 Steam boiler selection
Fig. D.1.3.1–3
Twin-pass waste heat boiler for generating steam
Flue gas outlet
Twin-pass waste heat boiler
In cases where the waste heat boiler
is very long compared to its diameter,
the pipe bundle can also be split. The
flue gas inlet and outlet points are
Flue gas outlet
then both located on the same side.
This more compact design is often
practical for applications with smaller
volumes of flue gas and lower flue
gas inlet temperatures
Flue gas inlet
Flue gas inlet
100/101
Fig. D.1.3.1–4
Shell boiler for generating steam with one waste heat pass
ECO
Flue gas outlet,
burner combustion
Flue gas inlet,
source of waste heat
ECO for
source
of waste
heat
Flue gas inlet,
source of
waste heat
Flue gas outlet
Flue gas inlet
Fig. D.1.3.1–5 Waste heat boiler
Waste heat boiler for two flue gas sources, single-pass
In applications with smaller flue gas volumes, it is also
possible for two flue gas sources to be connected to the
same waste heat boiler. This reduces space requirements
and the outlay for technical equipment. However, the flue
gas ducting remains completely separate in order to prevent
any mutual interference
D.2 Product range
Product range
There are normative regulations for selecting steam boilers depending on
the fuel used.
In principle, liquid and gaseous fuels, along
with hot flue gases / extract air, can be
used for generating saturated steam in our
steam boilers.
The following fuels and heat sources are
employed:
„Natural gas
„Biogas
„Extra light fuel oil
„Heavy fuel oil
„Masut
„Bio-oil
„Animal fat
„Wood fuels (biomass)
„Hot flue gases, for example from
combined heat and power modules
102/103
D.2.1
Steam boilers
Note:
Higher operating pressures than 25 bar are
available on request.
restrictions in the output range above
16,000 kg/h apply due to normative
regulations.
(DIN EN 12953-3 Clause 5.4 - Fig. 5.4.1
Limitation of combustion output to
14 MWtherm. / see Fig. D.2-1)
The specified steam output limits apply
to operation with natural gas combustion,
depending on the permissible operating
pressure. In the case of HEL (oil) combustion,
Fig. D.2.1–1 Vitomax 200-HS, type M237 / M73A and M75A (gas and oil combustion)
* The steam output specified here
is a value solely for orientation
purposes. The actual steam output
depends on boiler pressure,
the fuel used and emission
requirements.
D.2 Product range
D.2.2
Flame tube temperature monitoring
(FTTM)
FTTM systems appropriate for the system in
question (see tabular values) and compliant
with national regulations are required for
ɘ ) and
selected combustion outputs (4
F
the correspondingly designed flame tube
diameter (df):
Fig. D.2.2–1
Flame tube diameter depending on combustion output (additional measures)
Fuel parameters
HEL fuel oil
ɘ (MW)
4
F
df (mm)
ɘ (MW)
4
F
df (mm)
ɘ (MW)
4
F
df (mm)
Gas
≤ 12
≤ 15.6
> 1400
> 1400
> 12
> 15.6
> 1400
> 1400
> 12
> 15.6
< 1400
< 1400
(Source: DIN EN 12953-3)
In addition to DIN EN 12953-3, measures are
specified as follows in the trade association
agreement (version 11/2004) [Germany] and
must be considered accordingly during the
selection and sizing processes.
Note
Fig. D.2.2–2
Flame tube temperature monitoring
Criterion
Generally, where P355GH
is used as material
(only permissible for
corrugated flame tubes), a
temperature measurement
system must be installed.
Also for a combustion
ɘ F) and flame tube
output (4
diameter (df) of:
GI > 1400 mm
ɘ > 12 MW (oil) and
4
F
ɘ > 15.6 MW (gas)
4
F
Flame tube
diameter
≤ 1400 mm
Measures
„
Heat load limit according to EN 12953 up to a flame tube load of 12 MW in
the case of oil combustion or 15.6 MW for gas combustion - applicable to
flame tube material P295GH.
„
Max. flame tube load of 8.0 MW in the case of oil combustion or 10.4 MW
for gas combustion - applicable to flame tube material P265GH.
„
Max. flame tube wall thickness of 20 mm must not be exceeded in the case
of oil and gas steam boilers.
„
A wall thickness of 22 mm is possible when boiler and feedwater are
monitored, in accordance with the DDA information on installation and
operation of land-based steam boiler systems, or a temperature capturing
system is installed.
Flame tube
diameter
> 1400 mm
„
Flame tube wall temperature monitoring with 6 test points arranged offset
along the circumference at an angle of 120 °C.
„
1st row with a clearance of 0.8 dF ,
„
2nd row with a clearance of 600 mm downstream from the 1st row,
„
Limit and non-equivalence monitoring, temperature limiter and internal
inspection of the flame tube on the combustion side at 18 month intervals,
commencing 6 years after commissioning.
Combustion
output
> 12 MW (oil)
> 15.6 MW (gas)
„
Flame tube wall temperature monitoring with 6 test points arranged offset
along the circumference at an angle of 120 °C.
„
1st row with a clearance of 0.8 dF ,
„
2nd row with a clearance of 600 mm downstream from the 1st row,
„
Limit and non-equivalence monitoring, temperature limiter and internal
inspection of the flame tube on the combustion side at 18 month intervals,
commencing 6 years after commissioning.
104/105
Furthermore, a set of standardised hot
tensile tests must be conducted at 300 °C,
whereby the required strength values must
be adhered to and elongation at break must
not be less than the corresponding value at
room temperature.
In addition to the specifications of the 2000/1
trade association agreement, provision
must be made for an inspection interval
of 18 months for internal inspection of the
combustion side of the flame tube.
D.2.3
Economiser (ECO) operation
Depending on the relevant operating
parameters (saturated steam temperature = f
(operating steam pressure)), two versions are
usually employed for ECO operation as socalled integral ECOs.
With feedwater inlet temperatures into
the ECOs of 102 °C and operating steam
pressures of up to 12 bara), a differentiation is
made between:
„Type 100 - for flue gas temperatures
downstream from the ECO of 180 °C and
„Type 200 - for flue gas temperatures
downstream from the ECO of 130 °C
Design and calculation datasheets (see
technical guide for the respective boiler) for the
Vitomax 200-HS steam boiler with integrated
ECO, type 100/200.
Subject to observation of other flue gas
parameters required on site, such as:
„Specification of dew point temperature for
cold start
„Flue gas bypass operation
„Utilisation of condensing technology in the
case of specific and regulated "flue gas
condensation"
additional ECO designs are available in
combination with the respective steam
boiler as "mounted economisers" and/or as
"downstream economisers" in the case of
separate design and calculation according to
requirements.
Fig. D.2.2–3
Flame tube outputs
Regulation
TRD with trade assoc.
DIN EN 12953 or TRD with trade
agreement 94/1 [Germany]
association agreement 2003/1 [Germany]
Oil combustion
10.5 MW
14.0 MW
Gas combustion
13.65 MW
18.2 MW
Material
HII
P265GH (max. 8 MW oil,
Max. combustion output
max. 10.4 MW gas combustion)
Max. nominal wall thickness
17 Mn4
P295GH
20 mm
22 mm
Reason:
A:
Insofar as EL fuel oil or E natural gas are used
as the main fuel and S fuel oil, for example,
is intended as a backup fuel, the heating
surface of the ECO is designed for the main
fuel. So that the lamellar tubes of the ECO are
not contaminated beyond permissible levels
during the combustion of S fuel oil and hence
made ineffective or flue gases contaminated
with sulphur condense and destroy the ECO,
the ECO heating surface is "bypassed" in
this instance.
Additional use can be made here of
manufacturer-specific ECO designs
(supplier variable).
Any equipment-dependent "additional costs"
are amortised in less than 6 months through
the heat recovery achieved (integral ECO)
from the flue gas and the associated average
fuel savings of 4 to 7 %, assuming an annual
system operating time of approx. 6000 hours
(see rough calculation example in chapter
D 3.2.2).
A reduction in flue gas temperature using the
ECO of approx. 100 K yields an expected boiler
efficiency increase of approx. 5 %.
B:
If existing flue systems require minimum
temperatures.
a)
For operating steam pressures of
> 12 bar to ≤ 25 bar, an increase in
the saturated steam temperature
occurs as a consequence of
the rise in pressure (saturated
steam temperature = f (operating
pressure); see Tb. 2/2.1,
chapter G2) and thermodynamically
an analogous increase in the flue
gas temperature to be expected.
D.2 Product range
D.2.3.1
ECO output
In a thermodynamic economy consideration
covering the flue gas heat exchanger (ECO),
the necessary total ECO output (in kW) can
be estimated, derived respectively from the
following formula:
T)*ERLOHUT)*(&2
4
ɘ (&2
[સ%[૘L
$
T)*ERLOHU
7)*ERLOHU7air[
T)*(&2
7)*(&27DLU[
2
$
%
>@
%
>@
2
7)*ERLOHU
ᚐXHJDVRXWOHWWHPSHUDWXUHERLOHUฬᚐXHJDVLQOHWWHPSHUDWXUH(&2
>r&@
7)*(&2
ᚐXHJDVRXWOHWWHPSHUDWXUH(&2
>r&@
7DLU
FRPEXVWLRQDLUWHPSHUDWXUH
>r&@
DFWXDO2YDOXHLQGU\ᚐXHJDV
2
>[email protected]
LQWKHFDVHRI2UHJXODWLRQEHLQJDYDLODEOHZLWKUHVLGXDOR[\JHQ
સB = estimated amount of fuel to be expected
[m3/h or kg/h]
સ%
સB
૷FS
Note
hD
The economics must
take into account the
amount of feedwater,
since this is greater than
the amount of steam due
to blow-down and T.D.S.
losses. As no reliable
values are available in
this connection when
sizing the system, it is
usual to set steam mass
flow rate = feedwater
mass flow rate.
FS
h
Fw
H
ǹ
i
K(m)
૷)6[K
)6K
):
+L[Š.P
[
= estimated amount of fuel
in kg/h and/or Nm³/h
= amount of steam per steam boiler
in kg/h
= steam enthalpy - fresh steam
in kWh/kg (kJ/kg)
= feedwater enthalpy
in kWh/kg (kJ/kg)
= lower net calorific value
in kWh(kJ)/kg, and/or kWh(kJ)/Nm³
= average thermal boiler efficiency in %
as an expected value 93.5 % (assumed
selected value range: ≥ 92.5 % to
≤ 93.5 %) - and/or from datasheet as a
function of boiler load and ECO version
Fig. D.2.3–3
ECO with lateral outlet
106/107
Fig. D.2.3.1–1 A and B - Siegert factors = f (fuel); (constants)
Fuel
Constants:
Constants:
Constants:
Constants:
Factors
Light fuel oil
Heavy fuel oil
Natural gas
Town gas
A
0.67
0.69
0.66
0.63
B
0.007
0.007
0.009
0.011
Fig. D.2.3.1–2
Hi – lower net calorific value in kWh/kg, (kJ/kg) and/or kWh/Nm3 (kJ/Nm3)
Fuel
Fuel oil (EL)
Heavy fuel oil (S)
Natural gas (E)
Natural gas (LL)
kWh/kg
11.9
11.3
--
--
kJ/kg
42,700
40,700
--
--
kWh/Nm³
--
--
10.35
8.83
kJ/Nm³
--
--
36,000
31,800
Fig. D.2.3–4
Note regarding the estimation of Q̇ECO
With reference to the Vitomax 200-HS
datasheets (in this instance, the specifications
for determining flue gas mass flow rate using the
steam output), the respective ECO total output
can be determined with an increased degree of
accuracy for ECO types 100/200 from:
4
ɘ ECO = (h FG/boiler - h FG/ECO) x ૷ FS x R/ ̖ FG
ZLWKh FG/boiler - ᚐXHJDVHQWKDOS\DWERLOHURXWOHW
Generally determined from h FG =
in kW
N:K1Pu
T N:K
1Pu
FG
DQG
h
DQG
̖ DYHUDJHᚐXHJDVGHQVLW\RQWKHDVVXPSWLRQ ̖
DQG
GLPHQVLRQOHVVIDFWRUGHWHUPLQHGIURPWKHDIRUHPHQWLRQHGGDWDVKHHWV
5
GHSHQGLQJRQRSHUDWLQJSUHVVXUHDQG(&2W\SH
ᚐXHJDVHQWKDOS\DW(&2RXWOHW FG/ECO
FG
ECO mounted on top
.:K1Pu
FG
NJ1Pu
a)
Steam enthalpy of fresh steam
calculated in kWh/kg [Tb. 2/2.1]
= f (available steam parameters –
pressure/temperature) for
superheated steam and h"FD - for
saturated steam.
D.2 Product range
Fig. D.2.3.1–5
Economic considerations on steam boilers
TFG/ECO; hFG/ECO
TFW
ECO
h'FW= 0.001163 x TFW (kWH/kg)
૷FS =
amount of fresh steam per steam
boiler (kg/h)
hFS = steam enthalpy - fresh steam
(saturated steam (h''FS) and/or (hFD)
superheated), determined from
(Tb.2/2.1) = f (available steam pressure
and fresh steam temperature)
TFw = feedwater temperature (°C) (deaeration
temperature as a function of deaerator
pressure from (Tb. 2))
h'Fw = feedwater enthalpy in (kWh/kg)
Tab. 2, chapter G2
TFG/boiler
ŠK(M); hFG/boiler
D.2.3.2 Amortisation Economiser (AECO)
The values determined in chapter D.2.3.1
would result in a payback period from the
relationship:
SB
K ECO x H i
૷FS; h''FS
A ECO =
.
QECO x k B x b
with the additional calculated amounts that will
be required and must be provided, such as:
સB; Hi; Tair
KECO - expected ECO costs (in €) via a quotation
that must be prepared for each case
Steam boiler (SB) economics
consideration with ECO (simplified)
Fig. D.2.3.1–6
Heating surface temperature diagram
Note
The following cost functiona) may be of initial
assistance as a "rough" estimate:
.
.(&2 [QECOLQ೼
Flue gas outlet
300
ECO flue gas inlet
250
200
kB - current specific fuel price in (€/kg and/or
in €/Nm³)a)
Media temperature in °C
150
a)
b - expected annual hoursb) (full-load hours)
of system operation to meet the total annual
steam requirement.
100
50
0
100
50
Heating surface in %
150
The cost function is calculated
on the basis of corresponding
quotation work (Rosink, 2005/2006).
b)
Necessary preparations by the
customer.
200
250
108/109
Example estimate calculation:
with a resulting total ECO output of
.
Q = 365 kW
ECO
a energetic heating price for natural gas (H) of ೼ 0.04/kWh,
but with reference to the specific consumption:
N% ೼N:K[+L ೼N:K[N:K1Pu
N% ೼1Pu
an expected ECO price of:
.(&2 [N: ೼
and the assumed annual hours under full load
E = 6000 h/a
$(&2 results in a payback period of:
[
[[
\HDUV
Note
.
Die determination of Q ECO has been calculated on the basis of values and calculation variables yielded
with the formulae in chapter D.2.3.1:
Fuel
= natural gas (E)
Steam pressure
= 12 bar
Feedwater temperature Tfw
= 102 °C
Flue gas temperature w/o ECO TFG/boiler
= 252 °C
O2 content in flue gas
= 3 %
Siegert factors
A
= 0.66
B
= 0.009
Lower net calorific value Hi
= 10.35 kWh/Nm³
Saturated steam enthalpy h''FS
Feedwater enthalpy h'fw
Amount of steam in ૷Fs
Boiler load
ECO type
Flue gas temperature with ECO TFG/ECO
Air temperature Tair
Boiler efficiency (acc. to datasheet) ŠK(m)
= 0.7737 kWh/kg
= 0.119 kWh/kg
= 12,000 kg/h
= 100 %
= 200
= 132 °C
= 20 °C
= 94.75 %
Note
Current gas and oil prices can
be found on the internet at:
www.heizoelboerse.de
www.verivox.de;
www.carmen-ev.de
D.2 Product range
D.2.3.3
Utilising condensing technology
Condensing technology can also be used, on
the basis of currently known facts, for the
purpose of heat recovery on high pressure
steam boilers.
Additional costs are also amortised in this case
within reasonable payback periods (see sample
estimate). However, an essential condition
here is - as constantly as possible - the
availability of heat sinks at the corresponding
temperature level below the water dew point
in the flue gas, each depending on the fuel
used (see Fig. D.2.3.3-1).
The improvement in efficiency of the steam
boiler system enables a contribution to be
made to environmental protection. At the
same output from the steam boiler system,
the level of CO2 emissions is reduced by
approx. 9 % for natural gas operation (see
Fig. D.2.3.3-2).
With the increased values for gross cv and
the increase in steam dew point temperature,
use of condensing technology and natural gas
operation offers better conditions than HEL.
As a consequence of the chemical reaction in
the combustion (oxidation) of methane
&+2 !+2&
Fig. D.2.3.3–1
Gross and net calorific values of natural gas and HEL fuel oil
Fuel
Lower calorific
Upper calorific
Ratio (%)
Steam dew
value
value
gross cv/net cv
point in flue
(net cv)
(gross cv)
x 100
gas (°C)
Natural gas (E)
10.35 kWh/Nm³
11.46 kWh/Nm³
110.72
58
Natural gas (LL)
8.83 kWh/Nm³
9.78 kWh/Nm³
110.75
58
Fuel oil (EL)
11.9 kWh/kg
12.7 kWh/kg
106.72
47
The efficiency of the steam boiler system
(Š K(M)) is further improved and can achieve
values ≥ 100 %, with reference to the lower
net calorific value (net cv).
The increase in steam boiler system efficiency
(Š*) largely depends on the level of additional
"available heat" (QFGHE) "extracted" by means
Note
Condensate yielded
from HEL combustion
is very acidic (pH values
between 1.8 and 3.7)
and corrosive due to the
sulphur content in the
fuel (approx. 0.2 %).
Neutralisation facilities
must be equipped
accordingly with
additional active carbon
filters. Theoretically,
amounts of condensate
up to a maximum of
1.035 kg/kg of fuel
can be produced (see
Fig. D.2.3.3-2).
of condensing technology and is determined
from:
ǹ ǹ .0[
ɘ
4
)*+(
૷ )6K
)6K
IZ
>@
with the calculation variables as specified in
chapters D.2.3.1 and D.2.3.3.
theoretical maximum levels of steam
condensate equal to 1.5 kg/Nm3 of fuel are
produced in the flue gas, in the case of natural
gas combustion and pH values between 3.5
and 5.2 (slightly acidic).
Prior to their discharge, these must be
neutralised accordingly to pH values of
between 6.5 and 9, for example using filters
filled with dolomite and/or dosing equipment
employing sodium hydroxide (see technical
guide "Water quality standards for steam boiler
systems", [Appendix 2, chapter G1]).
110/111
The previously mentioned "downstream ECO"
could be included in the design as a secondary
heat exchanger to the existing integral ECO.
The "downstream ECO", the whole of the
secondary flue system and all dewatering lines
must be made in this instance from corrosionresistant stainless steel.
Fig. D.2.3.3–2 Theoretical amounts of condensate and CO2 generation in the case of complete combustion
Fuel
Max. theoretical
Max. CO2 emissions (kg/kWh) with reference to
amount of condensate1,2
QHWFY
JURVVFY
Natural gas (E)
1.63 kg/Nm³
0.2
0.182
Natural gas (LL)
1.53 kg/Nm³
0.2
0.182
Fuel oil (HEL)
1.035 kg/kg
0.312
0.298
As a continuously available heat sink, alongside
any that might be available on site in such
cases as:
„Low temperature heating systems
„DHW heating systems
„Low temperature process heat, technically
necessary preheating stages etc.
modulating, controlled preheating of the boiler
top-up water (softened water, upstream of the
inlet into the feedwater deaeration system) is
also conceivable.
1
With reference to the amount
of fuel.
2
Applicable municipal regulations
must be observed on discharge
into the local public sewage system
(e.g. in Germany, Code of Practice
ATV-DVWK-A251).
One system version of a steam boiler with
integral ECO and secondary flue gas heat
exchanger for utilising condensing technology
is indicated for information in the process flow
diagram (see Appendix A1) on the basis of
Fig. D.2.3.3-3.
Steam boiler (SB) economic considerations
with ECO and FGHE (simplified)
Fig. D.2.3.3–3
Steam boiler economic considerations
TFG/FGHE (ื 60 °C)
qFG/FGHE ; qFG/CON
with the calculation:
qCON-heat gain in % from utilising condensing technology, calculated from:
h'add/FW/O
q =
con
(H -H ) ˞
s
H
i
Tadd/FW/O
x 100
i
FGHE
qFG/ECO
The total FGHE heating output (in kW) and the amortisation (A) to be
expected in this instance are determined on the same basis as that for the
ECO in chapter D.2.3.1 and D.2.3.2.
Q̇
FGHE
FG/ECO
-q
=
)+q ]
FG/FGHE
con
x સ x H
B
100
i
and
A=
K
Q̇
x Hi
FGHE
x K x b
FGHE
ECO
Q̇
FGHE
h'
add/fw/O
- h'
add/fw/I
[
kg
h
h'FW; TSW
૷FW
[a]
b
TFG/boiler
As well as the additional amount of feedwater required for condensation
of the steam in the flue gas from the heat balance on the flue gas heat
exchanger (FGHE):
૷add.fw=
Tadd/FW/I; ૷add/FW
TFG/ECO (ุ 130°C)
˞ = condensation factor between 0.7 and 1.0 depending on coolant
temperature
[(q
h'add/FW/I
]
With inlet temperatures of the required additional feedwater "significantly"
lower than the steam dew point (see Fig. D.2.3.3-3).
ǹK(M)
SB
૷FS
h''FS
સB; Hi; Tair
D.2 Product range
Flue gas heat exchanger (FGHE)
Downstream from the ECO as a 2nd stage heat recovery device utilising condensing technology
and the parameters for top-up feedwater inlet and outlet:
h'add/fw/I = Enthalpy of additional feedwater (inlet) in (kWh/kg)
h'add/fw/O = Enthalpy of additional feedwater (outlet) in (kWh/kg)
Tadd/fw/I = Temperature of top-up feedwater (inlet) in (°C)
Tadd/fw/O = Temperature of top-up feedwater (outlet) in (°C)
૷add/fw = Amount of top-up feedwater in (kg/h)
Example as a rough calculation:
Taking the same assumptions and values as the rough calculation
in chapter D.2.3.2, the additional assumptions for:
„Flue gas temperature downstream from the
flue gas heat exchanger
= T FG/FGHE = 60 °C
„Top-up feedwater inlet temperature
= Tadd/FW/I = 10 °C
= Tadd/Fw/O = 50 °C
„Top-up feedwater outlet temperaturea)
„Expected price for the flue gas heat exchanger
≈ €105,000b)
„For a calculated total FGHE heating output
= Q̇FGHE
1.019 kW
result in an expected payback period of:
A
FGHE
=
k
Q̇
x Hi
FGHE
x K x b
FGHE
[
$)*+(
[[
b
ป\HDUV
with an increase in efficiency to:
Š Š
(
K(M)
Q̇
1+
FGHE
૷ (h'' -h' )
S
FS
fw
)
= 94.75 x
(
1+
1019
12,000 x (0.7737 - 0.119)
)
≈ 107%
and a top-up feedwater requirement due to the FGHE of:
Q̇
૷add/fw=
h'
add/fw/O
FGHE
=
- h'
add/fw/I
1019
(0.0584 - 0.0118)
21,867 kg/h
Note
With reference to the amount of fresh steam selected in the calculation example, an additional gain
would result on site from the heat "extracted" from the flue gas by means of condensing technology of:
Q̇add/gain ≈ (21.867 - 12,000)kg/h x (0.0584 - 0.0118) kWh/kg ≈ 460 kW.
In the event of non-availability of an appropriate additional "heat sink", Qadd/gain remains unused and the
increase in efficiency is reduced accordingly to the value of:
Š 94.75
(
1+
(1019 - 460)
12,000 (0.7737 - 0.119)
with the payback period increasing to:
a)
The feedwater outlet temperature
from the FGHE should always be
set at a value "significantly" below
TFG/FGHE.
Selected tender price.
b)
[
$
[[
ป\HDUV
)
≈ 101.5 %
112/113
D.2.3.4
Superheater (SH) operation
Appropriately designed and controlled
superheaters are brought into service based
on the requirements of on-site applications.
Superheated steam temperatures of 50 K
above the respective saturated steam
temperature can be achieved in the case
of unregulated SH operation and 100 %
boiler load.
For customer selection of the superheating
temperature differentials (Δ tSH), all the
temperature losses (heat losses) between
the steam boiler installation location and the
consumer must be considered (see chapter
D.8.3.4).
A reduction in superheating temperatures to
values < 50 K must also be considered subject
to boiler load.
Fig. D.2.3.4–1
Boiler load (%)
˂7 .
Boiler load
35
50
75
100
25
35
44
50
Specific requirements concerning safety
measures for preventing excessive pressure
as well as the necessary pressure and
temperature measuring technology in
operating modes with SH are considered
by the manufacturer with reference to the
applicable regulations (TRD 401).
Customer-specific superheating temperatures
of > 50 K are possible, however, in the case
of individual design in consultation with the
manufacturer (see example layout).
Fig. D.2.3.4–2
Mixing valve
0
Customer
set values
૷SH
૷SB
hSH
hSB
TSH
K
M/S૷M/S
Example - rough calculation
Regulated superheater in mixed operation
with saturated steam:
(Vitomax 200-HS; saturated amount
of steam = 10 t/h, saturated steam
temperature = 195 °C, pressure = 13 bar,
set value temperature for superheating =
220 °C at approx. 20 % boiler load)
Boiler load (%)
20a)
40
60
80
100
˂7SH (K) unregulated
20
42
59
72
82
˂7SH (K) regulatedb)
20
25
25
25
25
SH
Fig. D.2.3.4–3
Steam superheater
Standard values with reference to steam
output at a saturated steam pressure of 12 bar
and feedwater temperature = 102 °C
With a requirement for superheating of 50 K
in any of the specified load cases < 100 %, an
appropriately regulated SH operating mode
must be ensured by the manufacturer.
Control takes place here "within the assembly"
by means of flexibly controlled mixing of
"colder" saturated steam as a function of the
superheated temperatures arising downstream
from the mixing point.
Note
Alternatively, it is possible to install an injection
cooler or a surface cooler downstream from
the superheater or a controller on the flue gas
side to regulate the superheating temperature.
a) b)
The specified boiler load of
20 % in the calculation example
represents a "special case".
Normally, the minimum boiler
load is fixed by the manufacturer
at 35 %.
D.2 Product range
Principle of admixing saturated steam
Required mixing amount of saturated steam
(in ૷M/S) from:
૷06 ૷6%[K6+K6%
K6+K
06
NJK
and the calculation variables:
૷SB
Selected steam output (kg/h) on the
૷M/S
hSB
hSH
h''M/S
customer side
Required mixing amount of saturated
steam (kg/h)
Steam enthalpy (Tb. 2) (kJ/kg) as a
function of the customer set value
(pressure, temperature)
Steam enthalpy (Tb. 2) (kJ/kg) as a
function of the necessary superheating
temperature TSH for the purpose of
ensuring the on-site set temperature
Enthalpy of the saturated steam mixing
amount (Tb. 2) (kJ/kg) as a function of
selected saturated steam parameters
with the formulations from:
Volume statement -> ૷SB = ૷SH + ૷M/S (kg/h)
Heat statement ->
૷SB x hSB = ૷SH x hSH + ૷M/S · h''M/S
(kJ/h)
Consideration is frequently given to selecting a
boiler with higher pressure and subsequently
implementing a pressure reduction by means
of superheating.
This approach is illustrated in Fig. D.2.3.4-4.
It is, however, a purely theoretical approach.
In practice, the enthalpy of superheating
is used up by the wet steam content, so
that actually no appreciable superheating
temperature can be achieved.
114/115
Fig. D.2.3.4–4
1st and 2nd grade in Mollier-h, s-diagram for steam (theoretical consideration)
h (Enthalpy)
co
)
r (ü
ba
ts = 209,5 °C
ta
ns
=
=
nt
18
t=
p FD
ts
e 2:)
ic
(Cho
ü)
ar (
8b
C
= 1 9,8 °
0
2
=
ba
=
co
tan
=
co
nt
ta
ns
=
8
ba
ts = 188 °C
tB = 185 °C
ts = 175,4 °C
B
A
p FD
ts
ü)
r(
ns
RV
(Choice 1:)
Reduction at
h=constant
from A to B
ü)
r(
11
ü)
ar (
1b
= 1 8 °C
8
=1
t
tan ng
ns ati
co rhe
= pe
su
C
p FD
ts
(ü)
bar °C
= 8 75,4
1
=
D
x=
(sa 1
tu
rat
e
ds
te
am
pip
e)
S (Entropy)
Fig. D.2.3.4–5
Steam boiler with superheater
a) At constant steam enthalpy.
D.2 Product range
Fig. D.2.3.5–1
Indirect coil
ŠY67
+67ป
[૷)6[K
)6K
IZ
LQPt
NIP[˂7P
D.2.3.5
Pressure / heat maintenance steam boiler
The principle options are portrayed and
explained in chapter C.1.3.1 and Appendix A2
with 2 versions (VA and VB).
Aside from the portrayed versions:
(VB)
Pressure maintenance by means of
the combustion system and,
the following results, with the calculation
variables for:
Šv/ST Radiation loss of the steam boiler in %
૷FS Amount of fresh steam in kg/h
h''FS Enthalpy of saturated steam = f (pB) from
(Tb. 2) in kWh/kg
h'fw Enthalpy of feedwater = f (feedwater
temperature) in kWh/kg from (Appendix
Tb. 2)
kf(m) Mean heat transfer coefficients in the
case of free convection, according to
Appendix L8, between condensing
steam -> steel -> water (in kWh/hKm²)
and specifications between 0.291 and
1.163 kWh/hKm2
ΔTm Mean temperature differential (in K)
between the boiling point of the boiler
water as a function of the operating
pressure (pB) and "cooling" of the boiler
water content due to radiation loss, with:
ΔTmax
= maximum permissible "cooling"
and
ΔTmin
= minimum permissible "cooling"
and
the only permissible quotient in this case
the version here:
(VA)
Pressure maintenance using an
additional heating surface, (internal
indirect coil) installed in the water
chamber of the steam boiler, is the
most frequently used in practice.
Furthermore, it is the most
economical method in terms of
energy.
Note
The tubular heating
surface (HfR - German
abbreviation) must be
designed as an integral
"plug-in heat exchanger"
(if necessary as a U-tube
bundle) in the water
chamber of the steam
boiler (see Fig. D.2.3.5-2).
The benefit of this version in the case of multiboiler operation is the even distribution of heat
inside the boiler. Temperature stratification and
therefore thermal stress are avoided.
In the following, information and standard
values are provided for the approximate design
of the necessary tubular heating surface (HST):
From the relationship (calculation of the heat
transfer or heat flux through a tube wall)
˂7
PD[
˂7
ื
PLQ
the necessary tubular heating surface is
calculated with
˂7P ˂7PD[˂7PLQLQ.
116/117
Calculation example for determining the
tubular heating surface - HST:
With assumed values for:
૷FS
= 12,000 kg/h
pB
= 13 bar
Šv/ST
= 0.35 %
h''FS
= 0.7744 kWh/kg
h'fw
= 0.121 kWh/kg
kf(m)
≈ 0.727 kWh/km2
ΔTmax
= 20 K
= 10 K
ΔTmin
ΔTm
=(20+10)/2 = 15 K,
(selected feedwater temperature Tfw≈ 104 °C)
a tubular heating surface of approx.
ŠY67
+67ป [૷)6[K
)6KIZ
ป
[[
NIP[˂7P
Pt
[
would be required.
This yields a required total number of tubes n,
and selected diameter 33.7 x 2.6 mm:
+67
Pt
Gš[˭/7
[˭[P
Fig. D.2.3.5–2
Selected: 6 pieces
Plug-in heat exchanger
RW
RS
KB
HfR
dØ
x
DE
x
x
DN 150
Q
2x pipe = Ø 33.7 mm
KO
x
1x pipe = Ø 33.7 mm
Rb
Tb
View (x) pipe floor
"Plug-in heat exchanger" as an
equipment option for the calculation
example
Key:
RW =
Steam boiler tube wall
RS
=
Tube connector with
Rb
=
Tube plate (Rb) and
DE
=
Hot steam inlet
dished end (KB),
separation plate (Tb)
KO =
LR ~ 4 m
~ 51 mm
t 1.5 x dØ
Condensate outlet
dØ
=
Tube external diameter
t
=
Tube spacing
n
=
Number of heating tubes
LR
=
Heating tube length
D.3 Combustion systems
Fig.: Weishaupt
Combustion systems
Insofar as no particular make is specified by the customer, the optimum burner is
selected with regard to technology and cost-effectiveness.
When sizing the burner, the fuel types and
total combustion output must be considered
with reference to country-specific type
approval regulations (in Germany, 1st/4th
BImSchV; TA-Luft and/or 13th BImSchV).
A selection can be made, for example, from
the external "burner product lines" offered by
Dreizler, Elco, Saacke and Weishaupt.
The recommendation for the control side is:
„Gas as fuel: modulating
„Fuel oil
2-stage up to approx. 2.3 t/h
steam boiler output
and
modulating for >
2.3 t/h steam boiler output
118/119
Note
Design case:
Fan motor rating (N)
40 % saving
Annual hours run (Ohrs)
Annual saving
Electricity costs (Kelec)
D.3.1 Variable-speed combustion air fan
„Depending on the annual hours run and the
associated load
„If applicable, with recommendation for
electrical connected loads ≥ 8 kW motor
rating and an expected average annual
operational load of around 50 %
: 30 kW
: 12 kW
: 6000 h/a
: 72,000 kWh
: €0.08/kWh
1 1yQQ
Annual saving [KSC] from:
Rough estimate for speed control:
Where a speed controller is used on a burner
fan motor, approximately 40 % of electricity
costs are saved in the case of average boiler
utilisation.
KSC = 6000 h/a x €0.08/kWh x 12 kW resulting
in an annual saving KSC of €5760 p.a.
Additional benefit:
Reduction in the sound pressure level,
because the burner fan need not deliver 100 %
continuously.
The investment outlay for a speed controller
amount to ~ €3500, thus resulting in a payback
period (ASC) = €3500 / €5760 of ~ just over
6 months.
Fig. D.3.1–1
.6& 2KUV[.HOHF[1
Comparison of fan controller types
40
25
20
su
con
r
e
Pow
it
15
10
5
0
kW
in
w
tion
mp
W
in k
co
nt
ro
l
30
rol
ont
c
e
l
rott
h th
pe
ed
Power consumption of the fan motor in kW
Comparison of types of fan control
35
ns
r co
e
w
Po
0.01
2
4
Burner output in MW
6
n
tio
p
um
i th
w
8
s
10
With the characteristic
fan curve as a function
of the electrical
output from:
12
(in kW), the electrical
power consumption
of the motor drops to
approx. 1/8 on reducing
the speed by a half
(from n1 = 100 % load to
n2 = half load of 50 %).
Payback period = f
(actual system load
characteristics and local
electricity costs).
D.3 Combustion systems
Note
D.3.2
With O2 control for
values ≤ 3 % O2, the
excess air coefficient
(˨) is minimised
stoichiometrically.
The system efficiency is
improved by values of
up to 1 %.
„In the stoichiometric binding between fuel
and combustion amount of air
„If applicable, with a recommendation for
combustion outputs > 10 MW, for the
purpose of optimum compliance with legal
requirements relating to NOX emissions in
the flue gas
„A further improvement in system
efficiency of up to 1.3 % would be possible
with combined regulation by means of
hooking up the CO content to the O2
controller, i.e. O2 control = f (CO content in
flue gas), but only for gas operationa))
O2 control
Fig. D.3.2–1
Rough calculation
for O2/CO control:
Reduction of the O2 value in gas combustion
from 3.5 to 1.0 % yields an improvement in
efficiency of approx. 1.25 % for a flue gas
temperature of approx. 240 °C.
This corresponds to a fuel saving (in HEL):
„at 10 t/h, 75 % load and 6000 h/a of
39,500 l HEL p.a. and
„at 15 t/h, 75 % load and 6000 h/a of
59,200 l HEL p.a.
Note
At a flue gas temperature of 150 °C, the
efficiency improvement is still ~ 0.8 %.
Comparison of methods of fan control
$"'%" # #""$#"(#!
#" "
a)
With increasing CO content, the O2
content (excess air) can be reduced
to a stoichiometric minimum (limit).
However, any further reduction
results in a 'sudden' steep increase
in the CO content, particularly for
HEL operation. With gas operation,
the 'suddenness' is not as
marked and therefore more easily
controlled.
'% $"
#!" "# &
120/121
D.3.3.2 Annual fuel demand (સB(a))
D.3.3 Amount of fuel / fuel demand
D.3.3.1
Fuel demand (સB) - see chapter
D.2.1 (total output)
Determined as a standard value from (L5)
using:
The requirement is determined from the
specified balance equation as follows:
સ%
૷)6K
)6K
IZ[
સ%D
NJK
+L[Š.0
સ%D
The efficiency selected here ŠK(M) must be
taken from the steam boiler datasheets, loadbased and a choice of with and/or without ECO
operation.
After determining સB, it is possible to calculate:
„Combustion output (burner output)
Q̇C = સ B x Hi (kW) and
„Rated steam boiler output
Q̇SB = Q̇C x Š K(M)
in kW
and/or
Q̇SB = Q̇C x Š K(according to SB datasheets)
in kW
As long as a burner report is available, the
efficiency of the boiler can be calculated as
follows:
ǹ N
*
A, B
2GU
˽)*
˽$
$
2GU
%
assuming 2 % system loss
Siegert factors, see Fig. D.2.3.1-1
actual O2 content in flue gas, dry
flue gas temperature
air temperature
[˽)*˽$
E[4
ɘ &[Š.[
E[4
ɘ &[Š.[
+LyŠWRW
+L[Š.[Š%[ŠY
E[4
ɘ &[
+L[Š%[ŠY
NJDDQGRU1PD
with:
Q̇C combustion output (kW)
Hi
lower net calorific value in (kWh/kg)
and/or (kWh/Nm³)
b
expected annual full cost hours
Štot total system efficiency (%)
ŠK standard utilisation level of the boiler
according to SB datasheets (%)
ŠB standby efficiency (%), caused by
standstill of the steam boiler due to
radiation and cool down assuming
0.3 to 0.4 % radiation depending
on thermal insulation and boiler load
= 98 %
Šv distribution efficiency (%) depending
on system thermal insulation and
layout, assuming between 90 and
98 %.
D.3 Combustion systems
D.3.3.3
Combustion calculation simplified
Determined as a practicable value from
L4/L5 for gas and fuel oil as the fuel. If a
"precise" determination is required, see the
appropriate literature references.
Here, the "precise" determination is based on
given fuel analysis values.
Fig. D.3.3.3–1
D.3.4
Combustion air, supply air ducts
With reference to the versions referred to in
chapter C.4.1 (combustion air), the combustion
air required for combustion (see chapter
D.3.3.3 for calculation) can be taken directly
from the steam boiler installation room and/
or via separate supply air ducts from the
"open air" (outside the building). Ensure that
a pressure of +/- 0 mbar is available in the
boiler room.
Combustion air and flue gas volumes
L min in:
Fuel
Nm³
kg
Natural gas (E) =
Natural gas (LL) =
Fuel oil HEL(S) =
0.260 · Hi
1000
VFG min in:
or
Nm³
Nm³
- 0.25
Nm³
kg
0.272 · Hi
1000
0.209 · Hi
0.173 · Hi
1000
1000
0.203 · Hi
1000
+ 2.0
or
Nm³
Nm³
+ 0.25
+ 1.0
0.265 · Hi
1000
with the calculation variables:
Lmin - theoretical amount of air (˨=1);
VFG min - theoretical flue gas volume
(flue gas volumetric flow rate) (˨=1);
Hi
- the lower net calorific value of the fuel
for fuel oils (in kJ/kg)
and/or for gases (in kJ/Nm³)
With a 'minimum' possible air excess (˨) as
the objective for combustion in general of
between:
˨ ~ 1.1 to 1.3
˨ ~ 1.2 to 1.5
Note
Conversion of the
calculated air and/or flue
gas volumes from Nm³/h
to m³/h using:
Nm3/h x (1 + 0.00367 xT)
= m3/h
(T= available media
temperature in [°C]
also in the case of
disregarding the
operating pressures).
for gas combustion and
for oil combustion,
the specific air requirement (L) and the
expected specific flue gas volume (VFG) are
yielded from:
L = ˨ x L min
in Nm3/kg or Nm3/ Nm3
and
VFG = VFG min + (˨ - 1) x L min
in Nm3/kg or Nm3/ Nm3
Option A
Where air is drawn from the installation
room, provision must be made in the planning
process for appropriate "open air" vents.
Observe the following during the on-site
design of the "open air" vents:
„Supply air vent in the outside wall directly
behind the steam boiler (standard practice)
„Lower edge of vent approx. 300 to
500 mm above upper edge of floor
„Vent aspect ratio max. 1:2
„Open air vent (approximate) Avent ~
150 cm² + (Q̇C - 50) x 2 in [cm²] with
Q̇C = combustion output in [kW]
(FeuVA -Brandenburg, version `97)
„For output greater than 20 MW, the
following recommendation applies:
Combustion output > 20MW:
A vent ~ 150 cm² + (QC - 50) x 1.8 in cm²
„Where an open exhaust air vent is
required, standard practice dictates the
selection of 60 % of the "open" supply air
cross-section
122/123
Notes
Coordination necessary with the responsible
authority (approved monitoring body,
labour inspectorate, LaGetSi and/or
planning authority)
„Maximum negative pressure in the steam
boiler installation room 0.5 mbar = 50 Pa
(TRD 403)
„Safeguarding "free from frost" in
the installation room with air room
temperatures ≥ 5 °C to ≤ 30 °C
„For expected air temperatures < 5 °C,
provide appropriate air preheating, for
example, by installing spiral fin tube heater
banks in and/or upstream of the "open"
supply air vent, with frost protection for
the heater banks. Separate room heating,
e.g. by installing wall mounted air heaters,
is only recommended in the case where
longer interruptions in operation of the
steam boiler system are scheduled for the
winter months
„Combustion systems are usually designed
for "standard air conditions"
Air density
– 1.2 kg/Nm³
Air temperature
– 20 °C
Installation height
above msl
– 0m
and an
O2 content in flue gas – 3 %
„Air room temperatures ≥ 0 °C to ≤ 5 °C
and ≥ 30 °C to ≤ 40 °C result in a decrease
or increase respectively in the air volume
flow rate. The "fluctuations" in flue gas
O2 content arising in this instance can be
compensated for in a technically simple
manner by providing an O2 regulator
An association (to be observed when ordering)
between changing air volumes at a constant air
mass flow rate
D.3 Combustion systems
Fig. D.3.4–1 Air calculation
Densityair (kg/m³) at:
Height (m)
Pressure
above msl
(mbar)
10 °C
20 °C
30 °C
0
1013
1.247
1.205
1.165
250
983
1.210
1.169
1.130
500
955
1.176
1.136
1.098
1000
899
1.107
1.069
1.034
1500
846
1.042
1.006
0.973
„Installation of deflectors in duct deviations
(especially in the case of 90° deviations) to
ensure as laminar an air flow as possible
„If possible on site, a straight discharge
section of approximately (2 to 3 x dgl)
should be provided after a 90° deviation
(especially directly upstream of the burner
connection)
With dgl - the equivalent diameter determined from:
9ɘDLU ૷DLU̖DLUGHQVLW\
depending on air temperature and installation
height, is evident from Fig. D.3.4-1.
Option B
With an intake from the "open air" (outside the
building), "pressure-tested" supply air ducts
are required to the burner. "Frost protection"
for the installation room, air temperatures for
combustion air and system installation heights
must be observed in the same way as for
option A.
The following must also be observed when
designing supply air ducts on site:
„Guarantee of air leak tightness and
resistance to pressure in accordance with
the expected pressure development as a
function of arising duct pressure losses
and back pressures to be overcome
„Required determination of pressure losses
in the supply air duct taking account of
any fitted parts, such as intake silencers,
heater banks, deflections, fabric expansion
joints etc. (see calculation in chapter D 9)
„Required determination of the back
pressures to be expected (pressure drop
on the flue gas side) for:
„
Boilers with and/or without ECO
(see datasheet for Vitomax 200-HS)
„
Flue pipes taking account of any fitted
parts, such as expansion joints, flaps,
deflections and flue gas silencers
(calculation in chapter D 9)
GJO
[GXFWFURVVVHFWLRQ
[yD[E
GXFWVL]H
[DE
with "a" and "b", the clear lateral duct lengths
„Selection of sheet metal wall thickness
that guarantees structurally stable
operation; standard practice here is to
select a sheet metal wall thickness of
between 3.0 and 5.0 mm. Where a "thinner
wall" is selected (≥ 1.5 to ≤ 2.5), additional
bandages made from L-profile steel
would be required. A computed structural
verification is nevertheless recommended
for deformation (buckling)
„For sizing required flow cross-sections,
values for the standard flow rate of
between 10 and 15 m/s are recommended,
whereby the "smaller" values here are
intended upstream of the burner air intake
124/125
D.3.5 Acoustic emissions from
monoblock / duoblock burners
Taking account of the acoustic emissions
described in chapter E.1.4, "early" noise
protection measures that may be required
should be considered during the engineering
phase.
Having selected the burner type (see chapter
C.4), the following values can be assumed in
the first approximation:
„Sound pressure level in dB(A) (measured
1 m in front of the burner) depending on
burner type (monoblock or duoblock) as a
function of combustion and fan output
„
Values between 82 dB(A) and
115 dB(A)
„According to manufacturer specifications,
sound pressure levels of ≥ 100 dB(A) can
be anticipated for fan motor ratings as low
as ≥ 8 kWel
For expected values above 85 to 88 dB(A),
provision must be made accordingly for the
following noise reduction measures by means
of sound insulation (enclosure) combined with
sound attenuating (absorption), in accordance
with the [German] workplace regulations
(ArbStättV) in conjunction with guidelines
specified in VDI 2058.
a) For monoblock burners
Use of mobile sound insulation hoods
(enclosure and absorption) with a noise
reduction of between 15 and 20 dB(A),
depending on the type of sound absorption
material employed, and
b) For duoblock burners
Enclosure of the "externally" positioned
combustion air fan (if applicable, positioning
of the fan "straddling" the boiler top and/or
installation in a separate room (in the cellar
for example) below the boiler). This provides a
variety of design options with regard to sound
insulation, positioning and the choice of sound
absorption material. Depending on the version
implemented, reductions in noise emissions of
20 - 25 dB(A) can be achieved.
If so-called Low NOx burners are employed, it
may be necessary in certain circumstances to
equip the burner with sound insulation as well.
Note
Monoblock burners with a mobile sound
insulation hood require a corresponding
amount of free space in front of the
burner system for dismantling the sound
insulation hood.
Note
For fuel lines, see
chapter D.8.5.6.
In addition to the noise reduction options
described in a) and b), the "sound discharge"
(airborne noise) "into the open air" via the
system flue gas path (flame tube smoke
tubes, flue pipe and chimney stack) must also
be considered.
Depending on the structural design of the flue
gas path, e.g. 2-pass and/or 3-pass boilers
with/without ECO, type and number of flue
gas deflectors, attenuating noise levels in
respect of the sound emissions from the
combustion system of approx. 5 to 10 dB(A)
can be assumed at the stack opening.
If a more effective noise reduction is required,
additional sound insulation measures, e.g.
installation of a silencer in the flue pipe and/
or in the chimney itself, can be included in the
plan on the basis of permissible limits (official
setting of limits according to BImSchG, TA-Luft
and acquisition of an acoustic appraisal).
Recommendation
Sizing the silencer (in the case of subsequent
installation in the flue pipe) on the basis of
noise emission measurements taken after
commissioning the system.
Subsequent retrofitting must be taken into
account in the design by including appropriate
fitting elements.
Note
In addition to the
burners, it may be
necessary to sound
insulate the gas pressure
governors (flow noises)
and pumps as well.
D.3 Combustion systems
D.2.3.7
Determination of the amount of
wood fuel (biomass) required
The amount of wood fuel (biomass) required
can be determined on the basis of the net
calorific value and the required rated output.
One significant factor in this calculation is the
water content of the wood fuel, together with
the flue gas temperature.
4
%
+X
[Š
B Fuel demand [kg/h]
Q Rated output [kW]
Hu Net calorific value [kWh/kg]
Š Efficiency
Net calorific value of damp fuels
+X: +XDWUR:˂KY:
+XX
+XDWUR˂KYX
X
Hu atro Net calorific value, moisture-free, in
MJ/kg TS
W Water content in kg/kg
˂hv Enthalpy of evaporation of water
= 2.442 MJ/kg at 25 °C (standard
temperature for thermochemical
measurements)
The following applies to typical wood at 25 °C
+XX
X
X
>[email protected]
kWh/kg is also calculated instead of MJ/kg
(1 kWh = 3.6 MJ)
Example:
Water content W = 30 %, wood moisture u =
W/(1-W) = 0.15/(1-0.15) = 0.428 = 42.8 %atro
+X
0-NJ N:KNJ
The net calorific value Hu atro of completely
dry wood is, on average, 18.1 MJ/kg
(5.0 kWh/kg) for deciduous woods and
19.0 MJ/kg (5.3 kWh/kg) for coniferous woods.
For calculations with typical wood (CH 1 44O0.66),
the value is 18.3 MJ / kg (5.1 kWh/kg) >[email protected] The
net calorific values of plant fuels are slightly
less; typically, about 17 MJ/kg (4.7 kWh/kg) for
grass, 17.5 MJ/kg (4.9 kWh/kg) for straw and
about 18 MJ/kg (5.0 kWh/kg) for Chinese reed
(miscanthus giganteus).
126/127
Fig. C.2.3.7–1 Net calorific value of wood biomass subject to the water content
Feuchte
Humidity
u [%]
u [%]
= (atro)
= (atro)
0
11
25
20
43
67
100
150
5.5
5,5
18
55
Heizwert
Hu Hu
[MJ/kg
FS]FS]
Calorific
value
[MJ/kg
44
14
Soft wood(Hu
(Hu= =19,5
19.5MJ/kg;
MJ/kg;ww= =0)0)
Weichholz
3.5
3,5
12
33
10
2.5
2,5
Hard
wood (Hu
Hartholz
(Hu==18
18MJ/kg;
MJ/kg;ww==0)0)
8
22
6
1.5
1,5
4
11
2
0.5
0,5
00
0
0
10
20
30
40
60
50
Water contentww[%]
(%)
Wassergehalt
Fig. C.2.3.7–2 Efficiency subject to the fuel water content and flue gas temperature or load state
210 °C
190 °C
170 °C
150 °C
130 °C
94
92
Efficiency [%]
90
88
86
84
82
80
0
10
20
30
40
Fuel water content [%]
50
60
70
Heizwert
Hu Hu
[MJ/kg
FS]FS]
Calorific
value
[MJ/kg
4.5
4,5
16
D.4 Water treatment
Water treatment
Viessmann provides and offers appropriate treatment systems, taking into consideration
the information and comments specified in chapter C.4, focussing here on maintenance
of the feedwater and boiler water quality stipulated in the "Water quality" technical guide
(chapter G1, A3) and DIN EN 12953-10, tables 5.1/5.2 (see also chapter C.5).
Assignment of the individual components
for the required steam output is considered
according to the sequence indicated in chapter
D.4.3.1. Standard series with reference to
steam boiler output of up to 14 t/h are available
for selection from Viessmann.
This also applies to data deviating from the
standard values fixed in chapters D.4.1 and
D.4.2 for the respective designs. In principle, if
the boiler output lies between two component
sizes specified in the selection series, select
the next larger boiler.
For system concepts with higher boiler
output (steam boiler output ≤ 75 t/h), address
appropriately formulated enquiries to:
[email protected]).
a)
For system concepts with boiler
output > 14 t/h, the geometric
dimension to be expected here can
be taken as a first approximation
from the CWT datasheet.
128/129
D.4.1 Total deaeration system
D.4.1.1
Function description, standard
values, design assumptions
The total deaeration system comprises the
deaerator and feedwater tank assemblies.
To prevent corrosion, the deaerator is made
completely from stainless steel. The deaerator
is mounted directly on the feedwater tank, in
the form of a dome.
The feedwater total deaeration system is
designed to remove the gases dissolved in
the feedwater to a residual oxygen content
of ≤ 0.02 mg/l and provides the boiler system
with the water supply required for safe and
reliable operation. It operates with slight
positive pressure of approx. 0.1 to 0.3 bar.
The returned condensate and the chemically
treated top-up water are finely distributed
in the deaerator by means of so-called
lutes and brought together with the heating
steam flowing in the opposite direction by
the irrigation system. The steam heats the
condensate/top-up water mixture to boiling
point. The released gasses are drawn off to
atmosphere via a vapour valve positioned at
the highest point of the deaerator.
In the feedwater tank, the feedwater is fed
constantly with heating steam via an inbuilt
heating lance and thus maintained at operating
temperature.
The system is designed for a permissible
operating pressure of 0.5 bar. A safety valve
protects the tank from excessive pressure. A
vacuum breaker protects it against negative
pressure.
Prerequisites for satisfactory operation:
„Maintenance of a constant temperature in
the feedwater tank
„Continuous inflow
„Guaranteed unhindered extraction of
the vapour
„Maintenance of the level in the tank
„Insulation of the tank
„Maintenance of a geodetic inlet height
(Hgeo) up to the inlet suction port(s) of
the boiler feedwater pump(s), depending
on pump design (NPSH value), as a rule
between 2.5 and 4.0 m
Fig. D.4.1.1–1 Total deaeration system
Vapour outlet
Top-up
water inflow
Condensate inflow
dE
hE
Deaerator
Heating steam
Feedwater tank
htot
D
haeo
Feedwater
Source: Powerline
Note
The selection of too
low an inlet height
can lead to steam
formation in the pump,
with the consequence
of "sudden" steam
condensation and
associated cavitation for
the first stage impeller
blades in the inlet area
(see also "pump design"
in chapter D.6).
D.4 Water treatment
D.4.1.2 Total deaeration system
D.4.2
Standard values
„Minimum feedwater retention time (Ů) in
the feedwater tank ≥ 0.5 h to ≤ 1.0 h
„80 % tank volume as maximum level
„Approximate tank volume (Vfw ) in (m³)
from:
D.4.2.1
૷)6WRW[$[Ů
9IZa
>[email protected]
Deaeration takes place at atmospheric
pressure by means of a vent on the feedwater
tank. The tank is equipped with fitted parts for
the distribution and irrigation of the supplied
condensate and top-up water.
Steam boiler T.D.S. rate (%)
~ ≥ 2 to ≤ 5 % respectively
≥ 0.02 to ≤ 0.05 [-]
Feedwater is fed constantly with heating
steam via a heating lance built into the lower
part of the tank and thus maintained at an
operating temperature of approx. 95 °C.
„Guide values for deaerator sizing
Amount of condensate
> 50 to 100 %
Condensate temperature ≥ 70 °C
Amount of top-up water > 0 to 50 %
Top-up water temperature
10 °C
Feedwater temperature
(deaerator outlet)
102 °C
Temperature differential
using deaerator (heating) ~ 62 K
Fig. D.4.1.2–1
Function description, standard
values, design assumptions
The partial deaeration system is designed to
remove the gases dissolved in the feedwater
to a residual content of 1 mg/l and provides the
boiler system with the water supply required
for safe and reliable operation.
૷FS/tot Total amount of fresh steam (t/h)
A
Partial deaeration system
Prerequisites for satisfactory operation:
„Maintenance of a constant temperature in
the feedwater tank
„Guaranteed unhindered extraction of the
water vapour
„Maintenance of the level in the tank
„Insulation of the tank
Partial deaeration system
Condensate
inflow
Top-up water inflow
Venting
Note
The selection of too
low an inlet height
can lead to steam
formation in the pump,
with the consequence
of "sudden" steam
condensation and
associated cavitation for
the first stage impeller
blades in the inlet area
(see also "pump design"
in chapter D.6).
Heating
steam
Overflow
D
hhGes
tot
haeo
Feedwater
L
Source: Powerline
130/131
D.4.2.2
Partial deaeration system
Standard values
For low fresh water demands or small
amounts of steam, partial deaeration systems
can be purchased from Viessmann. If customer
specify a requirement for partial deaeration
systems with greater outputs, an increased
chemical requirement for bonding residual
oxygen must be expected.
At the same time, the following must be
observed:
As previously specified, the residual oxygen
content of the feedwater from a partial
deaeration system is 1.00 mg/l feedwater.
However, the requirement for steam boiler
systems with a permissible operating pressure
> 1 bar is 0.02 mg/l feedwater.
This residual oxygen content requirement can
only be achieved with a significantly higher
continuous dosing of chemicals than that
used in total deaeration. This results in higher
operating costs proportional to the hours run
and leads to unwanted increase in boiler water
salinity (see sample calculation below).
Necessary tank sizes must be selected
accordingly, analogous to the tank sizes for the
total deaeration system.
Example cost calculation:
Use of oxygen binders in partial deaeration
systems
In the following sample calculation, the
chemical consumption of a partial deaeration
system is compared with that of a total
deaeration system:
Basic assumptions:
„The consumption of oxygen binding agents
is 50 mg/mg O2
„The price per kg of binding agent is set at
€6.50
Boiler system with the following specification:
Boiler output amount of steam (૷FS): 3000 kg/h
Condensate return:
50 %
Feedwater temperature:
95 °C when using partial deaeration
Oxygen content:
1 mg/l at 95 °C
Feedwater temperature:
104 °C when using total deaeration
Oxygen content:
0.02 mg/l at 102 °C
Binding agent consumption:
50 mg/mg O2
Full-load hours run p.a. (b):
6000 h/a
Partial deaeration example
3000 kg/h x 1 mg/l x 50 mg/mg O2 x 50 %/100 x 6000 h/a x 10-6 kg/mg(binding agent)
= 450 kg/a x €6.50/kg = €2925/a
Total deaeration example
3000 kg/h x 0.04 mg/l x 50 mg/mg O2 x 50 %/100 x 6000 h/a x 10-6 kg/mg(binding agent)
= 18 kg/a x €6.50/kg = €117/a
If total deaeration is employed, in this example
€2808 p.a. would be saved in chemical costs.
With expected additional costs of approx.
€4200 from the use of total deaeration,
this results in a payback period (A) of
A = 4200/2808 ~ 18 months.
D.4 Water treatment
Further cost savings based on the
assumptions:
„Increase in the T.D.S. rate (ΔA) by approx.
2 % due to increased boiler water salinity
„Annual reduction in T.D.S water (૷red) on
employment of a total deaeration system:
„૷red = ΔA x ૷ FS x b = 0.02 x 3000 x 6000
= 360 x 10 3 kg/a = 360 t/a
„Cost saving (ΔK(red)) yielded by ૷red and
the costs assumed here for the additional
feedwater of approx. €3.50/t: ΔK(red)=
360 t/a x €3.50/t = €1260/a
„And hence a further reduction in the
payback period (Amo) to:
A mo(red) = KvgA / (ΔVT + ΔK(red)
= 4200/2808 +1260 = just over 12 months
with
Additional costs for a total
KVgA
deaeration system
ΔVT
Difference in costs for chemicals if
total deaeration is employed
D.4.3
D.4.3.1
Chemical water treatment system
(CWT softening system)
Function description, standard
values, design assumptions
Function description
The alkaline earths calcium and magnesium
are dissolved in water in the form of ions. In
water chemistry, these elements are referred
to as hardeners. Under the influence of heat
during boiler operation, these compounds
would form "boiler scale" that is deposited as
a solid coating on the heating surfaces. This
coating impedes the heat transfer from the
combustion to the water side.
Initially, this would result in higher flue gas
temperatures and therefore in reduced
efficiency. Any further increase in boiler scale
thickness could lead to the destruction of the
heating surfaces due to lack of cooling.
For this reason, the water standards specify
softened feedwater.
Process of boiler scale formation (CaCO3)
under the influence of heat:
&D+&2!&D&2+2&2
Systems with ion exchange resins are used
for softening the water. Ion exchangers are
spherical synthetic resins with absorbed active
groups. As an active group, ion exchangers for
softening water have absorbed sodium ions.
When the hard water runs over the ion
exchanger, the absorbed sodium ions are
exchanged for calcium and magnesium ions
that are dissolved in the water. The hardeners
that are detrimental to boiler operation are
thereby removed from the water.
Once the ion exchanger is exhausted, i.e. all
sodium ions have been exchanged for calcium
and magnesium ions, it is regenerated with
a sodium chloride solution (salt tablets for
regenerating the ion exchanger).
132/133
The sodium ions are channelled over the ion
exchange mass in the surplus and displace
the absorbed hardeners. Thereafter, the ion
exchanger is operational again. This process
can be repeated endlessly.
Loading:
51D&D0J!5&D0J1D
Regeneration:
5&D0J1D!51D&D0J
Standard values
„Raw water requirements:
„ Free from mechanical contamination
„ Free from iron and manganese
constituents, at drinking water quality
„Maximum total hardness in raw water
30 °dH
„Maximum raw water temperature 35 °C
„Minimum runtime of a system (filter)
between 2 regenerations 7 - 8 h
„Direct conductivity in boiler water
≤ 6000 μS/cm
„Residual hardness in treated water
≤ 0.056 °dH equivalent to ≤ 0.01 mmol/l
„Generally, use of double-pendulum
systems (2 filter systems) in the case of
corresponding sizing (see chapter D.4.3.1)
D.4 Water treatment
Fig. D.4.3.1–1
Size and parameters for the CWT system
Parameter
Unit
Size (BG)
Index
60
120
200
320
400
500
600
800
Rated capacity
m³x°dH
60
120
200
320
400
500
600
800
Output (ૺL)
m³/h
1.0
1.5
2.0
3.5
4.0
5.0
6.0
8.0
Ion exchanger filling
l
15
30
50
80
100
125
150
200
Salt consumption per regeneration
kg
Brine tank volume
l
Filter throughput
CWT softening systems - design:
In the following text, 8 types of system are
dealt with firstly, together with the indicated
technical parameters, for steam boiler output
of up to 14,000 kg/h as a function of the return
condensate content and the total hardness of
the raw water used (see Fig. D.4.3.1-1).
Note
For system concepts
with boiler output
> 14,000 kg/h, the
geometric dimension
to be expected here
can be taken in the first
approximation from the
CWT datasheet. The
rated capacity specified
in the table must not
be exceeded.
For system concepts with steam boiler output
> 14 t/h to ≤ 75 t/h, chemical water treatment
systems must be designed individually. This
also applies generally to data deviating from
the standard values stipulated in chapter
D.4.3.1. Please address any relevant enquiries
to [email protected] com.
From this, the maximum permissible additional
water requirement can be derived
9 DGGIZPD[ %*rG+[Ů=>[email protected]
3
6
10
16
20
25
30
40
100
100
200
300
300
300
300
520
1st sample calculation
Size (BG)
Water hardness
Filter runtime ŮZ.
between 2 regenerations
= 800
= 17 °dH
=7h
.
V add/fw(max) = BG / °dH x ŮZ [m3/h]
= 800 / 17 °dH x 7h
This yields a maximum permissible
additional feedwater demand of
.
V add/fw(max) = 6.72 m3/h.
Interpretation of the 1st calculation
example:
First approximation:
„For steam boiler output (૷ FS) > 6.72 t/h,
a corresponding condensate return of
(૷ CON) would be required on site:
૷ CON ≈ ૷ FS - V̇add/fw ̖m (t/h)
Assumptions:
Mean water density: ̖ m ≈ 1 t/m3
„For steam boiler output (૷ FS ) ≤ 6.72 t/h
with condensate return, the filter runtime
increases successively, whereby the
system-specific filter throughput must not
fall below values of ≤ 10 to 20 % to ensure
the specified rated capacity
134/135
2nd sample calculation
Calculation of size (BG) from the equation:
᧤ > @ ᧥
$
%* ̖
૷ )6 P
૷ &21
[]
[Ů=[rG+
The dimensionless value (BG) must always be below the system size specified in tabular form.
For example, with:
Total steam boiler output
On-site condensate return
T.D.S. rate
Raw water hardness
The required assembly size
%*ุ
᧤>
= 8 t/h
= 2.8 t/h ~ 35 % proportion of condensate
= 5 %
= 17 °dH
૷FS
૷CON
A
@ ᧥
[[ to be selected would be BG = 800, with the maximum permissible top-up feedwater volume, which
must not be exceeded from the 1st sample calculation, of V̇add/fw(perm) < V̇add/fw(max) equal to
᧤> @ ᧥
V̇ add/fw(perm)) ื V̇ add/fw(max) ู
Note
Regarding system design for steam boilers
> 10 t/h
Based on the following assumptions:
Raw water hardness = 17 °dH
Proportion of condensate = 50 %
Filter runtime ŮZ = 7 h
Maximum flow velocity through the
filter system ≈ 38 m/h
System construction similar to Appendix [A1]
each with an expected filter diameter (DF) of:
') [෭1ɘ/>[email protected]
and Ṅ L the maximum
filter throughput [m³/h]
5.6 m 3/h
6.72 m3/h
D.4 Water treatment
D.4.4
D.4.4.1
Function description - reverse
osmosis system (RO)
Standard values, design
assumptions
The osmosis system (referred to in practice
as a reverse osmosis system) desalinates
the required additional feedwater to the
greatest possible extent. The osmosis system
operates, as described in chapter C.4.2, purely
physically, whereby 70 to 98 % of the water
used is recovered as desalinated or partially
desalinated water. The water for which the
salt content must be reduced is filtered by
means of pressure through a semi-permeable
membrane that traps the salts (ions) dissolved
in the water. The membranes in so-called
modules have such small pores that the
smaller water molecules can pass through,
but the larger cations, anions and large organic
molecules are retained. Polyamide modules
can be exposed to water in the pH range 4 to
11 and modules made of cellulose acetone
in the pH range 4 to 7. A temperature limit of
approx. 30 °C (ideally 15 to 20 °C) applies to
both materials.
The pressure on the raw water side must be
higher than the osmotic pressure of the raw
water, which is dependent on its salt content.
The salts (ions) dissolved in the raw water are
retained on the raw water side (concentrate),
while the desalinated water (permeate) is
fed to the permeate tank on the permeate
side. This way, 0.75 to 0.9 m³ permeate is
collected from 1 m³ raw water. Depending
on the system design, this process removes
up to 99 % of salts from the original water
(raw water).
A softening system is installed upstream
of the reverse osmosis system to prevent
it from becoming blocked. In the case of
systems handling < 3 to 5 m³/h, an antiscaling agent is added to the raw water to
prevent blockages. The arising "slippage" in
hardness in the permeate of approx. 1 to 3 %
of the original hardness is then removed by
means of a downstream "polisher softener".
This downstream polisher softener must be
designed solely for the desalinated water and
the slight residual hardness of approx. 0.3 to
0.5 °dH.
Osmosis systems have found their "place"
in practice. Requiring very little space, they
are simple to maintain and well-suited to
continuous operation. Regenerating chemicals
are not required. Module service lives of up to
five years are currently expected.
Where an osmosis system is employed, a
downstream thermal total deaeration system
is absolutely essential for counteracting
CO2 surface corrosion. Aside from the salt
content, the carbonate hardness (also referred
to as alkalinity, m-value or KS4.3 value) has a
significant impact on the level of desalination
required. The reason for this is the alkalinity
of the boiler water, forming as a function of
carbonate hardness, boiler operating pressure
and available return condensate, that quickly
leads to increased desalination rates on
exceeding the threshold value (p value or KS8.2
value > 8 at > 20 bar, to 12 at < 20 bar). In the
case of carbonate harness values > 5 °dH,
operating pressure > 5 bar and condensate
rates < 20 %, desalination rates of 10 % have
already been achieved, justifying the use of an
osmosis system.
An RO system is to be recommended in the
case of:
„Salt content >800 to 1000 μS/cm
„Carbonate hardness > 5 °dH and no or very
little return condensate of < 10 to 20 %
„No or very little return condensate
„Boiler pressure > 5 bar as soon as the
above conditions apply
„Always where decarbonisation has been
used previously
Use of an RO system leads to a reduction in
the desalination rate to < 1 %.
Osmosis system - standard values:
„Continuous operation
„Raw water of drinking water quality
„Raw water temperature ≤ 30 °C
„Recommended for required desalination
rates (A) ≥ 8 to 10 % with reference to the
amount of fresh steam (૷ FS)
136/137
The desalination rate (Ai) can be estimated as:
a) the KS8.2 (p value as free alkalinity) - mmol/l
and/or
b) the conductivity - μS/cm and/or
c) the silicic acid content - mg/l from
᧤
$L
૷&RQ
૷)6
૷&RQ
૷)6
᧥
[
5
.5
[ >@ZLWK
>WKHSURSRUWLRQRI
[email protected]
૷Con = Condensate mass flow rate
૷FS = Fresh steam mass flow rate
R - Values for a), b), c) present in the raw water
according to raw water analysis
K - Limits of a), b), c) in boiler water according
to technical guide "Standard values for
water quality for steam boilers"
Note
The resulting maximum desalination rate
Ai must be set accordingly for the relevant
operation.
Sample calculation 1
Saline operation,
condensate content 50 %:
pH 8.2 ฬ KS8.2 mmol/l
Conductivity [μS/cm]
SiO2 - silicic acid
free alkalinity, p value
at 25 °C
[mg/l]
(R) Top-up water assumptions:
1
800
13
6000
150
[> 0.1 to ≤ 1 according to (L2)]
(K) Boiler water limits
12
(according to DIN EN 12953-10)
Ra)b)c)
Required desalination rate Ai (%)
Ai [%]
Ai = (1 - 0.5) x
Ka)b)c) - Ra)b)c)
Aa) = 4.54
=> desalination rates to be set would be: Ab) = 7.9 % > Aa) and Ac)
Ab) = 7.9
x 100
Ac) = 4.74
D.4 Water treatment
Note
Sample calculation 2
A reduction in the proportion
of condensate will result in an
increase in the desalination
rate. This increases the costeffectiveness of an osmosis
system.
Calculating the amortisation of the additional cost for an osmosis system compared with the
pendulum softening system
„Required desalination rates
≈8%
(without osmosis)
„Desalination rates
≈1%
(with osmosis)
„Proportion of condensate
≈ 50 %
„Rated steam output (૷ FS )
≈ 12,000 kg/h
„Rated steam pressure pB
≈ 12 bar
„Full-load hours run p.a. (b)
= 6000 h
„Total hardness of raw water
= 17 °dH
„Carbonate hardness of raw water
= 6.8 °dH
„Necessary additional cost (Δk)
≈ €16,280
through use of an osmosis system as an alternative to a pendulum softening system;
calculated on the basis of appropriate quotations (12/2007).
On use of an osmosis system, an annual reduction in desalination water ૷Red results of:
૷5HG
ෙ$
[૷)6[E[ W
NJ
[[
W
NJ
WD
With an assumed cost of approx. €3.50/t for the additional feedwater, an annual saving
Δk(red) = 5040 t/a x €3.50/t of €17,640 results and thus an expected payback period
Amo = Δk / Δk(red) = 16,280 / 17,640 of just under 12 months.
138/139
D.4.5 Water analysis, general
explanations
To ensure that the required residual oxygen
content in the feedwater (0.02 mg/l) is
maintained, chemicals are added to bind
the residual oxygen. The exclusive use of
chemicals to bind the entire amount of oxygen
is uneconomical in most cases.
The water-steam system is subject to
quality requirements regarding permissible
constituents. Depending on the pressure
stage of the generated steam, limits must be
complied with that are specified in the water
quality technical guide (5811 454).
The process described above is tried and
tested system technology. However, when
monitoring and operating this technology,
faults can occur from time to time. For this
reason, Viessmann has developed an analytical
concept to reduce the potential damage
caused by the chemical composition of water
as far as possible. Furthermore, this water
analysis method enables a more economic
operation of steam systems.
The feedwater must be treated in order to
comply with these standard values. The
processes employed for this purpose normally
comprise a combination of chemical and
thermal water treatment.
The hardeners in the untreated water are
bound together and extracted in a softening
system (see chapter C.5.1 Chemical water
treatment).
Depending on the requirements made of
the system with and/or without unattended
operation (BosB), the analysis technology
can be extended or reduced and is housed, if
necessary, in a separate analysis rack.
Furthermore, gases are dissolved in water that
are released on heating the water in the steam
boiler. These gases would inevitably result in
corrosion inside the steam boiler as well as the
downstream steam system.
The following figure illustrates the
interconnection options.
For this reason, top-up water from the
softening system is thermally treated, i.e.
deaerated, in a deaerating system together
with the condensate returned from the
consumer system (see chapter C.5.3 Thermal
water treatment).
Fig. D.4.5–1 Alternative integration of water analysis
5
Steam to the
consumer
1. Steam boiler with
combustion system
9
2. Thermal water treatment
13
3. Boiler feed pump
Top-up
water
4. Softening system
5. Chimney
11
2
HK
6. T.D.S. expander
7. Mixing cooler
1
Bypass
Feedwater
control
valve
Blow-down
valve
Raw water
14
3
9. Boiler system control panel
PK
12
O2
pH
8. Cooler tank or drainage
16
4
O2 pH
10. Condensate tank
11. Hardness test
12. O2 and pH test
13. Higher ranking control panel
with PLC for data transfer
7
6
Cooling water
Mixing cooler
8
14. Sample cooler for analysis
ÖT
LFS
17
15
10
Condensate
from the consumer
15. Conductivity test
16. Dosing of corrective chemicals
17. Oil turbidity test
D.4 Water treatment
Hardness checker (HK) for softened water
and condensate
This is installed downstream from the
softening system and, if necessary, also in
the condensate pipe (see chapter D.5.3). The
hardness checker continuously monitors the
softened water for residual hardness, without
consuming any chemicals or water.
When an unacceptable level of hardness is
discovered, "hard water" is indicated by a visual
display and a floating contact hooked up to
the PLC, one signal for the optical or acoustic
relaying and/or shutdown of the CWT system.
Operating principle
The differential pressure transducer installed
in the soft water pipe generates a slight
pressure differential when there is throughput.
As a result, a partial flow is diverted via the
hardness sensor built into the bypass and then
returned into the main stream.
The sensor is charged when hardness is
detected. At the same time, the special
resin inside the hardness sensor shrinks. A
transmitter unit with reed contact triggers the
visual "hard water" display.
The floating contact is used to confirm a visual
alarm signal and/or to shut down the doublependulum softening system.
O2 measurement
A significant role in monitoring feedwater is
played by the continuous measurement of the
dissolved oxygen concentration:
„Oxygen may only be present in low
concentrations (< 0.02 mg/l), otherwise
there is a risk of oxygen corrosion
„For this reason, a thermal and a chemical
water treatment system are installed on
the water side upstream of the boiler
system. This process must be maintained
continuously during boiler operation
„Non-continuous laboratory tests to
determine the oxygen content run the risk
of potentially incorrect sampling
„Continuous tests provide actual values at
all times and can be called up at any time
via the PLC memory
„Where TWT is installed for a multiboiler system, the amount of vapour can
optionally be adapted to the prevailing
demand depending on the actual
amount of feedwater. This results in
significant potential energy savings (see
chapter D.7.3)
Operating principle
Downstream of the sample cooler, a sensor
comprising a cathode (gold) and an anode (silver),
an electrolyte and a diaphragm are installed.
Oxygen diffusion through the diaphragm is
enforced by the partial pressure. A polarisation
voltage is applied to the two electrodes. In a
certain range, the detectable current is dependent
on the concentration of the infiltrated oxygen.
pH test (pH)
The actual pH value is a measure of the acidic
or alkaline nature of the feedwater. It enables
the CO2 content to be determined. In other
words, the lower the pH value, the higher the
CO2 content. The pH value should level out
between 9 and 10, and should always be > 9 in
order to prevent corrosion. However, it should
also never be higher than 10 in order to inhibit
the formation of sodium hydroxide.
Background
The alkaline earths, such as calcium and
magnesium, that are bonded with the
water are exchanged in the chemical water
treatment system (CWT) via ion exchangers
for active groups of sodium ions to prevent
the formation of boiler scale. In so doing,
sodium hydrogen carbonate is created. By
boiling under pressure, this breaks down into
sodium carbonate (soda) and CO2. When even
higher pressure is applied, Na-OH (sodium
hydroxide) forms along with further CO2 – the
so-called soda split. Since CO2 in conjunction
with moisture acts just as corrosively as O2, its
formation must also be prevented.
Operating principle
pH testing involves measuring a potential
differential (voltage in mV). This comprises
a reference voltage applied to a reference
electrode, where the medium to be tested
is in direct contact with an electrolyte and
the test electrode, where an ion-selective
membrane (for H+ ions) is located between
the test medium and the electrolyte. In order
to achieve good test results, a good electrical
connection must exist between the test
medium and the reference electrolyte. For this
reason, a liquid electrolyte is used, whereby
a small proportion of the electrolyte always
flows into the test medium.
Conductivity test (LFM)
Conductivity is tested in the condensate tank,
but preferably in the condensate feed line. This
detects any ingress of foreign matter in the
condensate.
140/141
Where this is the case, a downstream 3-way
valve drains the monitored condensate to
prevent any contamination of the water inside
the feedwater tank. Where there is a risk of oil
penetrating the system, the conductivity test
is extended to include a warning facility (see
"Oil turbidity test").
Operating principle
The condensate conductivity is tested to
detect ionic contamination. This is done using
two electrodes that have a constant voltage
applied to them via a measuring transducer.
There is contamination if the voltage in the
electrolyte (condensate) changes beyond a
permissible value.
Oil turbidity test
Apart from the aforementioned condensate
contamination, i.e. through an ingress of
hardness, salt or alkaline solutions, oils and
greases may also typically enter the system.
Where there is a risk of an ingress of oil, the
condensate must be monitored accordingly.
In such cases, the analytical equipment
is extended by the oil ingress monitoring
module, together with appropriate evaluation
and draining equipment for the condensate to
be discarded.
Operating principle
The oil and turbidity alarm is a visual signal.
The condensate flow to be measured is
illuminated with a light source. A receiver unit
is installed opposite the light source. As long
as the condensate is not contaminated, the
light signal is received unimpeded.
The light beam is deflected in case of oil,
milkiness or other turbidity. The deflection
ensures that a fault message is issued and
the condensate is discarded. The condensate
is drained away via a 3-way diverter valve.
The contaminated condensate must not be
introduced into the public sewage system.
It is discharged via so-called "de-oiling
systems".
Example: limit to be complied with for
oils/greases ≤ 3 mg/l
„For values > 3 mg/l
-> prior alarm with acknowledgement
„For values ≥ 5 mg/l
-> combustion "OFF" with lockdown
System control
All actual values are hooked up to a
programmable logic controller (PLC), where
they are evaluated and shown on a graphic
display. Excesses of the programmed limits
are registered in the fault memory of the PLC.
Actual values as well as fault and operating
messages can be transferred via the integral
Profibus interface to higher ranking control
systems.
Regulation of the chemical dosing pumps
based on the actual water quality generally
allows excess dosing to be omitted.
Optionally, the steam vapour flow and hence
the deaerator output can be controlled on the
basis of residual oxygen testing in accordance
with the actual amount of feedwater required.
This results in substantial fuel savings.
Analysis cabinet
For conducting regular analysis of top-up
water, feedwater and boiler water, Viessmann
offers a cabinet with all the necessary
equipment and chemicals.
With this the following analyses can be
carried out:
„Residual and total hardness
„KS8.2 and KS4.3 (p and m values)
„Sodium sulphite content (residual oxygen
binding agent)
„Phosphate content (residual harness
binding and alkalinisation)
Dosing equipment for corrective chemicals
To maintain the alkalinity of the feedwater,
to bind the residual hardness and to bind the
residual oxygen, corrective chemicals are
added to the feedwater. A number of products
are offered by water treatment companies for
this purpose. The water treatment companies
should always be consulted regarding the
conditions of use.
In most cases, two different dosing chemicals
are used; firstly, to remove residual hardness
by alkalinisation of the feedwater and secondly
for binding residual oxygen. As a consequence,
two dosing devices should always be
employed.
Viessmann offers chemicals for binding oxygen
and residual hardness and raising the level of
alkalinity in the boiler water. These chemicals
are intended for the initial setup and can each
be supplied in 25 kg canisters.
D.5 Condensate management
Condensate management
In the following chapter, the condensate systems introduced in chapter C.6 will be
examined in greater detail.
There follows a comparison between an open
vented and a sealed unvented condensate
system with an exemplary design, in order to
explain, on the basis of a clear example, when
it is worthwhile employing sealed unvented
condensate systems.
142/143
D.5.1
Function description of open vented
condensate systems
For alternative return rates (!14 m3/h) and
where sealed unvented systems are used
(see chapter D.5.2), address any enquiries
appropriately formulated to:
[email protected]
Standard values
„Expected condensate temperature
≤ 95 °C
„Available tank capacity
Vna)≈ 0.8 (૷ Con/2 to ૷ Con/3) [m3]
D.5.1.1
with:
૷ Con - maximum possible amount of
condensate arising (in t/h)
Standard values, design
assumptions
The condensate station is designed to collect
and return the condensate discharged by
steam consumers to the feedwater tank in the
thermal deaeration system.
The condensate tank is connected with the
atmosphere via an "open" air vent valve.
Condensate is therefore drained from the
consumers without any back pressure.
The condensate pumps (normally 2 x 100 %
pumps) return the accumulating condensate,
depending on the tank level, to the deaerator
in the thermal treatment system.
The tanks are equipped with the necessary
connectors for:
„Condensate inlet
„Condensate inlet (spare)
„Condensate outlet as condensate pump
connection on the suction-side
„Ventilation, vapour extraction
„Overflow
„Drain
„Inspection port (handhole and/or manhole,
depending on tank size) and
„Filling level display/regulator
Pumps and tanks are installed on a common
base frame made from steel sections and
do not require any separate foundations for
positioning. The floor on site needs only to be
level and capable of bearing the relevant load.
In order to prevent unnecessary energy
losses due to re-evaporation of the returning
condensate, open vented condensate systems
should really only be employed where
condensate temperatures below 100 °C are
expected.
Note
Otherwise, the system described in chapter
D.5.2 would be of greater benefit.
For system concepts >
14 m3/h to ≤ 75 m3/h, the
geometric dimensions
to be expected here can
be taken in the initial
approximation from the
Viessmann datasheets.
Deviating from the
Viessmann tank types,
versions are selected in
this instance in the form
of cylindrical tanks with
dished ends.
Pump
rate of condensate pumps (V̇ CON)
with feeding into the deaerator in the
feedwater deaeration system (in m³/h)
Assumptions
Constant feeding into the deaerator as a
prerequisite. Consequently:
૷ &21
ɘ &21 9
̖ &21
[ILQ[PK]
with condensate density - ̖CON as a function
of condensate temperature (see Appendix
Tb. 2.2)
With supplement factor f, a permissible
increase in pump rate, depending on deaerator
design (temperature differential over the
deaerator), should be considered.
Values between f ≈ (1.1 to 1.5) would be
conceivable here in practice.
„Condensate pump head (HCON) with
feed into the deaerator in the feedwater
deaeration system (in mWC and/or bar)
from the sum of individual proportions of
+&21 KKKKK[P:&EDU]
with the proportions (hi) for:
h1 - Deaerator positive pressure as back
pressure
h2 - Geometric height differential between
condensate tank installation position and
inlet point on the deaerator
h3 - Pipe friction losses
h4 - Individual pressure drop caused by fitted
pipe components (fittings, valves etc.)
h5 - Pressure gain due to positive pressure in
the condensate collector (only applicable
to sealed unvented systems)
a)
Assuming a constant condensate
return flow rate from the consumer.
In the case of non-continuous return
(unfortunately, the most common
case in practice), provision should
be made for an available capacity
of Vn ≈ 0.8 (૷Con to ૷Con/2).
A precise statement from the
customer regarding consumption
characteristics is an absolute
necessity.
D.5 Condensate management
Note
D.5.2
An option for determining
h3 and h4 is described in
greater detail in chapter
D.8.
Given the following assumptions:
h1
≈ 0.5 bar
h2
≈ 4 mWC ฬ 0.4 bar
h3 + h4
≈ 0.15 x (h1 + h2) ≈ 0.135 bar
h5
=0
this results in, with sufficient accuracy, a
required head of HCON = 15.35 mWC ≈ 1.5 bar
Fig. D.5.1.1–1 TWT - open vented system
Fig. D.5.1.1–2
High pressure condensate collector
Function description of sealed
unvented condensate systems
Sealed unvented condensate systems are
more extensive in terms of their processrelated construction than open vented
systems. The sealed system tanks used
here are fed with so-called high pressure
condensates at temperatures above 100 °C
and widely varying pressure levels.
The condensate tank is a pressure vessel
in accordance with the Pressure Equipment
Directive.
The major advantages of sealed unvented
condensate systems are:
„No ingress of oxygen into the system
from the air
„Steam pressure reserves in the tank can
be used simultaneously for transport, the
suction power of the feed pumps is lower,
potential signs of cavitation in the pump
can be minimised due to the pressure load
„Lower heat and water losses (cessation of
steam vapour)
„Reduction to a minimum of the
system internal power demand due to
use of the low pressure steam from
condensate expansion
144/145
The tanks are equipped with the necessary
connectors, as described in chapter D.5.1, but
without vapour extraction or overflow and with
the addition of the following:
„Safety valve
„Thermal ventilation
„Low pressure steam outlet in the case of
preferred feed into the deaerator and/or
feedwater tank
„Steam connection for pressure stabilisation
in the tank
As described in chapter D.5.1, the condensate
station also serves the purpose of collecting
and returning condensate from/to the steam
boiler released by steam consumers.
Appropriate condensate pumps (2 x 100 %
pumps) return the accumulating condensate,
depending on the tank level, to the deaerator
in the thermal treatment system.
Pumps and tanks are installed on a common
base frame made from steel sections and
do not require any separate foundations for
positioning, provided that the load-bearing
capacity of the substrate is sufficient.
D.5.2.1
Standard values, design
assumptions
See open vented systems in chapter D.5.1
with additional parameters, such as:
„Expected condensate temperature
≥ 100 °C
„Pressure gain due to positive pressure in
the collector h5 ≈ 0.2 bar
„Use of feed pumps with "low" NPSH
values (e.g. side-channel pumps)
„In practice, the high pressure condensate
is mixed with the additional feedwater in
an intermediate tank and then transported
to the steam boiler using high pressure
pumps. See also diagrams in Appendix 1
Shortfalls in terms of additional amount of
feedwater ૷fw = ૷FS - ૷CON, must be supplied
accordingly to the condensate collector via the
thermal water treatment system.
Fig. D.5.2.1–1
High pressure condensate integration with low freshwater requirement
Soft water
High pressure
condensate
e.g. 3-8 bar
Feedwater tank
e.g. 0.5 bar
Steam
Vitomax 200-HS
(e.g. 13 bar)
Sealed condensate
container
(e.g. 3-8 bar)
Optional
feedwater cooler
Optional feedwater cooler so that the temperature differential across the economiser is not adversely affected
Fig. D.5.2.1–2
High pressure condensate integration with similar amounts
Soft water
High pressure
condensate
Feedwater tank
e.g. 0.5 bar
Steam
Vitomax 200-HS
(e.g. 13 bar)
Sealed condensate
container
(e.g. 3-8 bar)
D.5 Condensate management
Fig. D.5.2.1–3
Comparison of open vented and sealed unvented condensate systems
Condensate system
Open vented
Sealed unvented
Condensate positive pressure
bar
0
3 to 8
Condensate temperature
°C
95
133 to 158
Expansion steama)
%
6.5 to 11.0
0
Heat lossb)
kWh/t
49 to 83
0
Water loss
kg/t
65 to 110
0
Note
Back pressure levels up to 5.0 bar are quite
plausible in practice and can increase system
efficiency significantly. For example, the
following indicated heat and water losses
could be taken into consideration accordingly
in a cost-benefit analysis (see Fig. 5.2.1-2).
This high pressure condensate is, for logical
reasons, introduced via a distributor located
upstream of the boiler feed, in accordance
with system diagram [A1], taking into
consideration a necessary feed pump head
and pump rate in compliance with regulations
(TRD 401, Clause 3), with:
Calculation example
Amortisation when a sealed unvented condensate system is employed:
Initial data:
Pump head ≈ 1.1 x pB (bar) and
Pump rate ≈ 1.25 x ૷FS (t/h) with
Fresh steam output
૷ FS
= 12,000 kg/h
Fresh steam pressure
pB
= 13 bar
Condensate return feed
૷ CON
= 6000 kg/h
at
Condensate pressure
pCON
= 5 bar
and
Condensate temperature
TCON
= 158 °C
Raw, softened water temperature
T RW
= 15 °C
Specific heat/water
cP
= 0.001163 kWh/KgK
Feedwater temperature
Tfw
= 104 °C deaeration
Raw, softened water cost
kRW
≈ €3.5/t
Natural gas (E) cost
kE
≈ €0.414/Nm³
Natural gas (E) lower net calorific value
Hi
≈ 10.35 kWh/Nm³
Full-load hours run
b
= 6000 h/a
a) See Fig. D.5.2.1-3.
b) With reference to steam enthalpy
0.75 kWh/kg in atmospheric
conditions.
pB - operating pressure of
the steam boiler(s) and
૷FS - fresh steam output of
the steam boiler(s)
With an expected doubling of additional costs
compared with selecting an open vented
system, payback periods of between six
months and 2 years can nevertheless be
achieved by utilising the specified "potential
savings", depending on annual full-load hours
run (see example calculation).
146/147
Potential savings (E) over the open vented system:
E1 - Savings in raw, softened water (ΔkRW(E1)) due to omission of re-evaporation in the case of
condensate expansion from pCON = 5 bar to ambient atmospheric pressure.
path = 0 bara) from:
ෙN5:( NJVWHDPNJFRQGHQVDWH[૷&21[E[N5:೼D
ΔkRW(E1) = 0.11 x 6000 x 6000 x 3.5 x 10-3 t/kg
ΔkRW(E1) = €13,860/a
E2 - Savings in fuel (ΔkB(E2)) due to omission of heating the additional amount of raw, softened water
(૷RW) from E1 with:
૷RW = (11 kg steam / 100 kg condensate) x ૷CON
૷RW = 0.11 x 6000
૷RW = 660 kg/h
and an efficiency ŠK for the steam boiler ≈ 89 %b), the following savings would result:
ෙN
૷ [F [7 7 5:
3
%(
IZ
+ [ǹ
L
5:
[E[N
[[
(
[
.
[[ ೼D
E3 - Savings in fuel (ΔkB(E3)) due to already elevated feedwater inlet temperature into the steam boiler
resulting from mixing of additional feedwater (tfw = 104 °C) into the sealed unvented condensate tank
(tCON = 158 °C) with a feedwater mix temperature (tfw/M) being arrived at in the condensate tank of:
7 [૷ 7 [૷
&21
7 &21
IZ0
IZ
૷ ૷
&21
IZ
LQr&
assuming ૷fw = ૷FS - ૷CON [kg/h]
IZ
Note: Desalination rate (A) = set to zero!
This results in a mixed temperature of
7 [૷ 7 [૷
7 &21
IZ0
&21
IZ
૷ ૷
&21
[[
IZ
IZ
r&
and therefore:
ෙN
૷ ૷ [F [7 7 IZ
&21
S
+ [ǹ
%(
L
ෙN
%(
IZ0
IZ
[E[N
(
.
[[
[[ ೼D
[
On observing all aforementioned values, an annual cost saving of
E = ΔkRW(E1) + ΔkB(E2) + ΔkB(E3) = 13,860 + 18,422 + 101,612 = €133,894 results.
Based on the approximate current cost for a sealed vented condensate system of
≈ €80,000 to €110,000c) and an annual cost saving ≈ €130,000, this results in a payback period A
≈ 0.62 to 0.84 years.
a)
See [Tb. 8].
b)
From Vitomax 200-HS datasheet
without ECO operation.
c)
Major proportion of additional
costs over open vented systems
(estimated costs) for:
- High pressure condensate tank
- High pressure condensate pumps
- More control equipment required
- Higher expenditure on pipework
and valves approx. €80,000 to
€110,000.
D.5 Condensate management
Sealed unvented system
Open vented system
5340 kg/h
EG
EG
Soft water
6660 kg/h
6660 kg/h; 15 °C
15 °C; raw soft water
0.2 bar (h)
0.2 bar (h)
SB
10 m3; 104 °C
SB
6 m3; 104 °C
TWA - thermal water
treatment with:
EG deaerator
SB feedwater tank
Feedwater
pumps
Feedwater
pumps
High pressure
condensate
Low pressure (LP)
condensate pumps
High pressure (HP)
condensate tank
LP condensate
pumps
૷)'=
12,000 kg/h; 13 bar (ü)
DE
ND-KG
Hm3
3 - 8 bar
ǹ. ~ 89 %
સ; Hi
૷)'=
Feedwater
pumps
12,000 kg/h; 13 bar (ü)
12,000 kg/h
Condensate
pumps
12,000 kg/h
approx. €80,000 to
€100,000
Diagram open vented / sealed unvented system
Expansion steam (૷E)
૷E=660 kg/h
Major proportion of
additional costs over
open vented systems
(estimated costs) for:
„High pressure
condensate tank
„High pressure
condensate pumps
„More control
equipment required
„Higher expenditure for
pipework and valves
Fig. D.5.3–1
૷)'=6000 kg/h:
9 bar (ü); 158 °C
Note
DE
ǹ. ~ 89 %
સ; Hi
148/149
Fig. D.5.3–2 Thermal total deaeration system
D.6 Pumps
Pumps
Sizing the feedwater pumps taking account of the control versions described
in chapter C.7.
On the one hand, the provisions of the relevant
regulations must be observed. On the other,
the specific circumstances of the actual system
must also be taken into consideration. For this
reason, various versions are presented here.
150/151
D.6.1
Feed pumps - criteria for design
and operation
Fig. D.6.1–1
Suction head or required inlet pressure (source: Grundfos)
H (m)
The task(s) of the feed pump(s) (also referred
to as boiler feedwater pump(s)) consist(s) of
feeding the steam boiler(s) with an amount
of feedwater corresponding to the amount of
steam generated. The pumps normally used
for this purpose are centrifugal pumps, taking
account of and complying with NPSH valuesa)
specific to the pumps; see following diagram
(Fig. D.6.1-1).
Minimum positive pressure
14
12
10
8
6
4
2
1.3
NPSH [m]
0
Maximum suction head
NPSH at standard atmospheric pressure
At a standard atmospheric pressure of
1013 mbar, the necessary inlet head or
maximum possible suction head can be
determined using the accompanying diagram.
Example
NPSH pump = 4.0 mWC
(manufacturer specification) at
media temperature = 90 °C
A minimum inlet pressure of 1.3 mWC must
be available at the pump suction port. This
includes a safety margin of 0.5 mWC.
The majority of pressure losses arising in the
pump suction line should be compensated for
with the specified safety margin of 0.5 mWC.
This assumes that the suction line is
designed to be as short as possible, i.e.
≤ 10 m in the case of moderate flow velocities
≤ 0.5 m/s in the suction line.
In special cases, a precise determination
of pressure losses that may arise must
be performed for the suction line; see
chapter 8.3.3.
-2
7
6
-4
5
4
-6
3
2
-8
1
0
-10
80
60
40
20
Media temperature
90
100
120
t (°C)
Note
The minimum necessary inlet pressure (pMIN)
with reference to the pump suction ports and
standard atmospheric pressure can also be
estimated from the following:
S0,1 S6(
136+SXPS[̖IZ
>[email protected]
with values for:
pS/E
NPSHpump
̖fw
Steam pressure in feedwater tank
(in bar)
NPSH value at 20 °C media
temperature (according to pump
supplier) (in mWC)
Feedwater density at operating
temperature (see Appendix Tb. 2.2)
(in kg/m³)
As orienting standard values, literature
reference L2 specifies:
Fig. D.6.1–2 Table
Feedwater temperature [°C]:
90
100
110
Required inlet head [mWC]:
2
4
6
a) Net positive suction head (see
diagram) - suction head and/or
inlet pressure, as a function of the
media temperature.
D.6 Pumps
Note
The NPSHavail value is
the available pressure
differential between
the total pressure in
the centre of the pump
inlet connection and the
evaporation pressure
pD (also referred to as
saturation pressure),
measured as a pressure
level differential in m.
To a certain extent, it
is an indication of the
evaporation risk at this point
and is only determined by
data relating to the system
and the pumped fluid.
According to DIN EN 12953-6 Clause 5.5,
sufficient feedwater must be made available
at maximum operating pressure (safety
pressure). According to TRD 401 Clause 3,
the following criteria must also (either/or) be
met. (In the following sample calculation, both
criteria are used.)
Feed pump head ≈ 1.1 x pBa) [bar]
„With the selected supplement of
10 % in addition to the head, the
arising pressure losses for connecting
pipes, built-in pipe components and
economisers, if applicable, can near
enough be compensated for and therefore
disregarded in practice.
This is conditional, however, on
maintenance of flow velocities in the
connecting pipes and built-in components
of ≤ 2.5 m/s throughout.
In special cases, a precise determination of
arising pressure losses must be carried out
for the pressure line; the calculated losses
are then added to the required head; see
also chapter D.8.3.
In the case of expected losses of A > 5 %,
with reference to the steam boiler output,
a supplement of 25 % + ΔA % would have
to be considered.
On determination of the pump head and pump
rate, the necessary pumps and/or associated
pump motor rating (N) can be calculated from:
1.ป
[૷)6[[S%
[[Š3
>N:@
the pump shaft output (NK) and a commonly
used output supplement as an compensation
for any fluctuations in the pump operating
point, which can lead to an increased pump
rate requirement (NK) in certain circumstances,
with a supplement (ZEL) in accordance with (L7)
according to the following Fig. D.6.1-2.
Permissible steam boiler operating
pressure ฬ safety pressure ฬ safety
valve discharge pressure.
Required pump rate and supplement
NK (kW)
up to 7.5
7.5 to 40
from 40
ZEL (%)
20
15
10
The pump motor rating from:
1ป
Pump rate ≈ 1.25 x ૷FS in t/h
„With the selected supplement of 25 % in
addition to the pump rate, the pressure
losses on the water side (blow-down
and desalination losses at A ≤ 5 %) are
completely compensated for.
a)
Fig. D.6.1–2
1.[
=(/
>N:[email protected]
Note on the determination of (NK):
The following equation applies in general for
the determination:
̖[J[+[9ɘ
1 .
>:@
ŠS
with
̖
– Density of the delivery medium
in kg/m³
g
– Gravitational acceleration in m/s²
H
– Pump head in mWC
V̇
– Pump delivery amount in m³/s and
– Pump efficiency of > 0 to < 1
ŠP
Taking account of conversion factors from Watt
to kW, mWC to bar and m³/h to m³/s or kg/h to
kg/s from the relationship
9
ɘ ૷)6
̖
the necessary "dimensionless" factor in the
denominator of the equation is calculated to be
0.36 x 105.
In the further course of derivation, gravitational
acceleration and density are divided, yielding
the equation for determining the pump
coupling rating (NK), as specified, with the
previously described multiplication factors
for the required pump rate (of 1.25) and head
(of 1.1).
152/153
Pump selection example
Notes
„Amount of fresh steam - ૷ FS = 12,000 kg/h
1. Note
„With inlet heads found in practice here of between
2.0 and 4.0 mWC, pumps are only recommended, in
principle, at NPSH-pump ≤ 4.0 mWC.
„During the process of pump selection, consideration need
only be given, in principle, to an associated flat curve
for the NPSH value, as a function of the pump rate (see
Fig. D.6.1-3), for the necessary operating range (between
minimum and maximum pump rate).
„Permissible steam boiler operating pressure - pzul = 16 bar
(safety valve discharge pressure),
„Operating temperature in feedwater tank - T B/E = 105 °C
„Steam pressure in feedwater tank
- p D/E = Ł T B/E from (Appendix Tb. 2) = 0.21 bar
„Feedwater density - ̖ FW = Ł T B/E from (Appendix Tb. 2.2) = 954.5 kg/m³
„Design case 100 %
Required pump volumetric flow rate (V̇ P) with reference to
operating temperature
1.25 x 12,000
1.25 x૷ FS
V̇
V˙ P =
=
= 15.72 m³/h
2. Note
„The pump efficiencies should achieve their optimum
values as far as possible in the range of the curve for
lower NPSH values. An electric limiter on the pump
motor for higher than permissible pump rates is also
recommended here.
954.5
̖ FW
„ Required head
(delivery pressure p D) = 1.1 x 16 = 17.6 bar
„ Required pump or drive output (N) at an assumed average pump
Fig. D.6.1–3
Pump curves (schematic diagram)
Operating range
efficiency (pump manufacturer specification) of Š p ≈ 75 %
to be selected
1 .
[ [
N:
and with ZEL~15 %
Delivery head (H)
Hmax
[[[
(H
(1.1 x pB)
(H) -
)-
(V̇ ) -
line
at n *
(V̇
)-
lin
ea
min
t n*
ma
x
Pump efficiency ŠP
N = 9.77 x
(
15
1+
100
H
)
≥ 11.24 kW
NPSH - pump
„ With a required assurance of NPSH values for the pump in the
**
V̇ MIN
range between NPSHPUMP ≥ 0 and ≤ 7 mWC, this would result in a
required minimum inlet pressure (PMIN) for the respective
borderline of between
Pump rate (V̇ )
*Assumptions:
pump speed regulation between
n*MAX./ n*MIN.
pMIN(NPSH=0) =
0.21 +
0.5 x 954.5
10 ≈ 0.258 bar
**Difficult to measure in practice, but NPSH
does not remain constantly min!
and for
pMIN(NPSH=7) =
0.21 +
9
ɘ MAX with limitation
(7 + 0.5) x 954.5
10 ≈ 0.926 bar
with a resulting geodetic inlet head (H geo) that can be generated of:
Hgeo(NPSH=0) ~ (pMIN(NPSH=0) - p D/E) x 10.2 mWC/ bar
Hgeo(NPSH=0) ~ (0.258 - 0.21) x 10.2 ≈ 0.49 mWC
Hgeo(NPSH=7) ~ (0.926 - 0.21) x 10.2 ≈ 7.30 mWC
with limitation
1.25 x ૷FS
ˮ
D.6 Pumps
Regular operation - technical boundary
conditions for practical operation, curve
characteristics, load cases, etc.
Supplementary to the specifications in
chapter C.7.1, the following provides further
detailed notes and recommended versions for
"practitioners".
A summary of the most common versions for
operation as single boiler systems is provided
for this purpose, with features, depending on
the control range, of the
„Steam boiler (load profile)
„Combustion system (burner)
„Pump (curve characteristic, minimum
pump volume) for versions 2, 3 and 4
1. Intermittent level control for boiler
systems without ECO up to max. 3 t/h
boiler steam output
This can be regarded as the simplest solution
for steam boilers without an economiser and
an output of up to 3 t/h. This version is not
recommended for steam output above 3 t/h or
when using an economiser.
Reason
On controlled shutdown of the boiler
feedwater pump (pump OFF, boiler water
demand lower than pump rate, minimum
burner load lower than the minimum pump
flow), the economiser does not receive any
flow on the water side.
Therefore, there would be no increase
in efficiency due to the ECO and/or
superheating.
Control function
The water level is regulated between two
adjustable fixed switching points, i.e. "pump
ON" and "pump OFF". The level electrode
signal has a corresponding effect on the pump.
Furthermore, steam hammer may occur in the
economiser.
2. Continuous level control by means
of a feedwater control valve for all
sizes of steam boiler with/without
economiser
Can be regarded as a simple solution for steam
boilers with or without an economiser. Here,
the feedwater control valve is regulated as
a function of the boiler level. The feedwater
pump shuts down if the flow rate falls below
a minimum level specified by the pump
manufacturer.
This version is not recommended if the
combustion output can be regulated to less
than the minimum amount of feedwater, and
an economiser is used.
In this case, the economiser would likewise
receive no flow on the water side.
Control function
The aim of the controller is to maintain the
level in the boiler at a fixed set value. The actual
value is continuously monitored by a level probe
and compared with the set value in a controller.
Opening and closing the feedwater control
valve regulates the level to the required set
value in the case of load fluctuations.
When the minimum pump rate is reached,
the pump shuts down and the feedwater
control valve closes (signal via limit switch in
the feedwater control valve and/or pump load
profile with minimum/maximum limitation).
This version is not recommended if the burner
control range is greater than the feedwater
pump control range.
3. Continuous level control by means of
a feedwater control valve/bypass valve
for all sizes of steam boiler with an
economiser
Here, the feedwater valve is regulated as a
function of the boiler level. If the flow rate
to the boiler falls below the minimum level,
the bypass valve is opened by increasing
pressure and lets the minimum volume
required for pump protection return to the
feedwater tank.
Control function
The aim of the controller is to maintain the
level in the boiler at a fixed set value. The
actual value is continuously monitored by
a level probe and compared with the set
value in a controller. Opening and closing the
feedwater control valve regulates the level
to the required set value in the case of load
fluctuations.
154/155
A partial volume is returned to the
feedwater tank via an adjustable minimum
flow line. This valve can be designed as a coneshaped butterfly valve or a control valve.
This so-called bypass line is designed to
protect the pump from falling below a
specified minimum pump rate. It ensures that
the economiser receives flow when the burner
control range > pump control range.
A PLC controller is a basic requirement for
switching purposes. The flow rate is adjusted
via the speed of the pump motor. This means
the feedwater volume can be regulated
down to a partial load that corresponds to the
minimum flow rate required for the pump.
The minimum flow rate depends on the type
of pump.
Please note!
The version shown here is one control option.
However, the preferred version is that depicted
under point 4 with feedwater control valve
with spillback. Bypass valves must be sized
hydraulically for each individual application.
Control function
The aim of the controller is to maintain the
level in the boiler at a fixed set value. The
actual value is continuously monitored by a
level probe (4-20 mA signal, e.g. NRGT 26-1
Gestra) and compared with the set value in a
controller.
4. Continuous level control by means of a
feedwater control valve with spillback
for all sizes of steam boiler with an
economiser
A change in the level results in variable speed
adjustment of the pump rate (in this case by a
mounted inverter, FU) to match the changing
demand, until the set level has been achieved.
This can be regarded as the preferred option
for steam boilers with or without economisers.
Here, the feedwater control valve with spillback
is regulated as a function of the boiler level. If
the flow rate falls below the minimum level,
the spillback valve opens and lets the minimum
volume required for pump protection return to
the feedwater tank. An additional butterfly valve
is not necessary in the bypass line.
The reduction in speed is limited by two
parameters:
1. Flow rate
2. Required pressure
The back pressure of the system (system
curve) must be overcome. For this reason, only
limited use can be made of the possible speed
range of the pump.
Control function
The feedwater control valve continuously
regulates the volume of feedwater depending
on the level. As soon as the main flow falls
below a certain feedwater flow rate (e.g.
30 %), the spillback connection (bypass) opens
wide enough to ensure that the required
minimum pump rate (e.g. 30 %) can always be
drawn off.
5. Continuous level control by means of
pump speed regulation for all sizes of
steam boiler with/without economiser
Inverter-controlled boiler feedwater pumps can
be employed in the case of steam boilers with
or without economisers.
Note
Use of an inverter pump
is not recommended if
the burner control range
is greater than that of
the pump, i.e. the pump
control range is < 1:4.
Power can be saved by means of this demanddependent speed optimisation. It also saves
on installation of control valves upstream of
the boiler.
6. Continuous level control by means of
pump speed regulation and bypass for
all sizes of steam boiler with/without
economiser
The determinations described under
point 5 apply.
Furthermore, depending on the project in
question, it can be necessary to use a bypass
line as an overflow line.
This is the case if, due to the system, the
control range of the pump needs to be choked
so far that the partial load of the burner is
lower than the partial load of the pump.
Note
Taking account of the
pump curve and the
load reduction, a bypass
cannot always be
omitted. One third of the
nominal flow rate can be
assumed as a standard
value for the minimum
flow rate of the pump.
However, a bypass does
not always represent
a loss of energy.
Depending on the load
profile (how long the
pump runs in bypass
mode), speed regulation
may be more practical.
D.6 Pumps
Fig. D.6.1–4
Grundfos pump (example 1)
Operating range
Whether and to what extent an invertercontrolled pump is worthwhile is shown in
Fig. D.6.1-4.
Curve field
Pump data:
Rated speed:
Nominal pump rate:
Minimum pump rate:
Rated head:
Maximum head:
Pump
Curve field
System
Assumptions:
Boiler output:
Permissible operating
pressure:
Ø positive operating
pressure:
Motor rating
in operating range:
Curve fields
Power consumption
Motor
Fig. D.6.1–5
360 - 2789 rpm
3 m³/h
0.9 m³/h
66.6 m
97 m
2.3 t/h
6 bar
4.5 bar
0.5 to 0.95 kW
Pump diagram for a pump without inverter control
Operating range
The figure opposite (Fig. D.6.1-5) is the pump
diagram for a pump without inverter control.
At this load, the conventional pump has a
power consumption of 1.14 kW.
Assuming that the boiler runs for a total of
8000 h/a and half the time at a load of 70 %,
the following power savings are possible:
„Power requirement 100 % load
(with inverter): 0.95 kW
„Inverter internal power requirement:
0.05 kW (approx. 5 %)
„Conventional power requirement at 100 %:
1.14 kW
„Difference over 4000 h:
560 kW
„Power requirement 70 % load
(with inverter): 0.78 kW
„Inverter internal power requirement:
0.02 kW (approx. 5 %)
„Conventional power requirement at 70 %:
0.95 kW
„Difference over 4000 h:
600 kW
At an electricity price of €0.06/kWh, this yields a saving of €70 p.a.
At this output, the investment outlay of versions 4 and 5 is almost identical.
Further benefits of pumps with inverter control:
Longer service life due to lower load.
156/157
Pump data:
Rated speed:
Nominal pump rate:
Minimum pump rate:
Rated head:
Maximum head:
Assumptions:
Boiler output:
Permissible operating
pressure:
Ø positive operating
pressure:
Control range:
Fig. D.6.1–6
2947 rpm
30 m³/h
9 m³/h
180 m
230 m
20 t/h
Grundfos pump (example 2)
Curve field
Pump
Curve field
System
16 bar
13.5 bar
Between 7.5 and
14 kW electrical
motor power
The figure opposite (Fig. D.6.1-7) is the pump
diagram for a pump without inverter control.
At this load, the conventional pump has a
power consumption of 16.7 kW.
Assuming that the boiler runs for a total of
8000 h/a and half the time at a load of 70 %,
the following power savings are possible:
„Power requirement 100 % load
(with inverter): 14 kW
„Inverter internal power requirement:
0.7 kW (approx. 5 %)
„Conventional power requirement at 100 %:
18 kW
„Difference over 4000 h:
13,200 kW
„Power requirement 70 % load
(with inverter): 11.5 kW
„Inverter internal power requirement:
0.6 kW (approx. 5 %)
„Conventional power requirement at 70 %:
16 kW
„Difference over 4000 h:
15,600 kW
Fig. D.6.1–7
Pump diagram for a pump without inverter control
H
(m)
200
160
120
80
40
0
0
5
10
15
20
25
30
35
Q (m3/h)
P2
(kW)
20
16
12
8
4
At an electricity price of €0.06/kWh, this yields a saving of €1728 p.a.
The additional investment outlay compared with version 4 are approx. €3000 with a
payback period of ≈ 1.74 years.
D.6 Pumps
Note
Continuous control by means of an inverter
on the pump is recommended if there are
frequent or severe fluctuations in the steam
demand and/or only partial load up to a defined
pump flow rate is required over a prolonged
period.
The inverter adjusts the pump speed (and thus
the pump rate) to the steam demand.
Consideration must be
given to the fact that some
pumps equipped with
inverters have a higher
connected load and the
motor transitions are not as
finely tuned, hence putting
the savings into perspective.
Basic contexts:
Ratio of throughput to speed
Q
4 4[
Q
Ratio of pressure to speed
+ +[
Q
Q
curves of every pump. The potential savings
are, among other factors, also subject to the
structural design of the pump.
Q
Index 1 = known point
Index 2 = required new point at new speed n2
Fig. D.6.1–8
120
100
80
As soon as the pump rate falls below a defined
"minimum flow rate", a so-called valve bypass
opens and hence always guarantees the
required minimum flow rate of the pump.
Pressure ˜ n2
Size
As an alternative to the described versions 4,
5 and 6 for "bypass operation", the use of socalled automatic recirculation non-return valves
should also be mentioned.
Automatic recirculation non-return valves
are self-acting safety valves that protect
centrifugal pumps from damage that can arise
during pump operation in low-load situations
due to partial evaporation and accompanying
cavitation.
Constant control by inverter
Output ˜ n3
60
40
Throughput ˜ n
20
0
If, however, the system load only changes
infrequently or within a small range, it can
also be practical, from the point of view
of investment and electricity costs (see
version 4), to use a continuous control valve.
The continuous control valve acts as a
throttle. At constant pump speed, the choking
generates a higher back pressure so the pump
can only deliver a lower flow rate. The output
requirement for the pump motor also drops,
albeit in a much lower proportion.
This correlation can be seen in the head/
flow rate and power consumption/flow rate
Q
Ratio of motor rating to speed
3 3[
over a particular period and the local costs of
electricity.
0
20
40
60
80
100
120
Speed
This means that, for example, at a change
in speed n from 100 % to 50 % (which
also corresponds to a change in flow rate
V from 100 % to 50 %), the motor power
consumption P drops to 1/8. This value is
theoretical because the inverter itself is also
a consumer of electrical power. The demand
of the inverter can be taken as approximately
5 % of the total output. The payback period
depends on the actual system load curve
The automatic recirculation non-return valve
is installed in the feedwater pressure line as
directly as possible on the pressure port of the
pump to be protected. A clearance should be
selected between the pump pressure port and
the valve inlet of no more than 1.5 m for the
purpose of minimising flow pulsations.
In order to safeguard the valve, an additional
so-called "manual start auxiliary outlet"
(option) can be opened in the event of
prolonged minimum discharge rates. The
auxiliary outlet is not, however, likely to be
regarded as essential in practice (in the case
of hydraulically coordinated designs combined
with load characteristics of the pumps to be
employed).
158/159
Straight-through internal diameter and nominal
pressure of the automatic recirculation nonreturn valves must be selected appropriately
for the pump pressure ports and are
commercially available for pressure levels from
PN10 to PN40. Valve main throughput and
minimum flow rates are specified as a function
of the straight-through internal diameter
(see Fig. D.6.1-9).
Fig. D.6.1–9 Valve main throughput and minimum flow rates
Straight-through internal diameter (mm)
25
32
40
50
65
80
100
125
150
Main flow ratea) (m³/h)
17
28
45
68
114
178
270
400
530
Minimum flow rateb) - standard - (m³/h)
6
10
18
18
40
40
65
65
116
Spillback internal diameterb) (mm)
25
25
25
25
40
40
50
50
65
One advantage of these automatic
recirculation non-return valves is valve
operation without auxiliary power, while
guaranteeing "low-wear" operation for the
bypass in the case of required system
operation always being greater than the "zero
pump rate" of the selected feed pump.
Notes regarding multi-boiler operation
For system operation with several steam
boilers, a wide selection of hydraulic control
options can be combined, with reference to
the actual operating case in question.
For example:
„Similar to the above, but with provision of
a separate inverter-controlled feedwater
pump for each steam boiler, with reference
to versions 5/6
„Three feed pumps (one of which a back-up
pump) for two steam boilers with fixed
allocation of pump to boiler, each with a
separate feedwater control valve as an
output for each steam boiler and common
bypass operation analogous to versions 3/4
from the distributor back to the feedwater
tank. This version can generate cost
savings due to omission of pumps, but it
also reduces the system availability
„Twin-pump units for each boiler, identical
to single boiler systems
a)
With reference to a maximum
permissible flow velocity in
the pressure line, appropriately
modified flow rates can also be
applied here.
b)
Depending on demand according to
pump selection.
D.6 Pumps
Reference to:
Datasheets - accessories for
high pressure steam boilers
Variable speed pump drives similar in design
to versions 5/6 in chapter D.6.1 are only
conceivable, however, for sealed unvented
systems.
Viessmann offers a matching feedwater pump
(Grundfos / KSB / Lowara / Speck / Wilo) with
or without speed control for all of its steam
boilers.
Variable speed pumps are not recommended
on account of the expected low motor rating of
condensate pumps in open vented systems.
Please address your enquiries to:
[email protected]
Sample calculation
D.6.2
Condensate pumps - criteria for
sizing and operation
1.ป
Reference is made here to the versions
described previously in chapters D.5.1
and D.5.2 (open vented/sealed unvented
condensate systems - standard values), but
with additional information on the need for
any applicable modulation of feed flow rates
into the feedwater tank and/or the steam
boiler directly by means of regulated bypass
operation using motorised control valves (see
Fig. D.6.2-1).
Condensate pumps with ૷CON ≥ 1.25 ૷FS
standard for open vented and sealed unvented
systems
„pS"open" = 1.0 barabs < pG/fwTank ≈ 1.5 barabs
„pS"sealed" = 3.0 to 6.0 barabs
< pG/SteamBoiler ≈ 7.0 to 26.0 barabs
[૷)6[[S%
[[Š3
>N:@
160/161
Fig. D.6.2–1
Bypass operation
Directly to the
feedwater tank
and/or steam boiler
with backpressure – PG
Open vented and sealed unvented
condensate tank at system pressure – pS
Bypass
Condensate pumps
D.7 Thermal equipment
Sizing the thermal equipment
With reference to the previous statements in
sections
C.5.4
Sampling cooler,
C.8.1
Mixing cooler,
C.8.2
T.D.S. expander,
C.8.3
Exhaust vapour condenser and
C.8.4
Feedwater cooler
the individual pieces of thermal equipment are
discussed in the following in terms of their
function and their "approximate" sizing.
System assignment can be taken here to
a limited extent from Viessmann standard
components with reference to the specific
data for steam boiler output > 14 t/h to ≤ 75 t/h
(see tables in Fig. D.7.1.1-2, Fig. D.7.2.1-2,
Fig. D.7.2.1-3 and Fig. D.7.2.1-4).
In case of deviation from the selected standard
values and initial values, enquiries should be
addressed to: [email protected]
162/163
D.7.1
D.7.1.1
Mixing cooler
Function description, standard
values, sizing assumptions
The mixing cooler does not require any special
foundations for its installation; the floor on site
needs only be level and capable of bearing the
relevant load.
The tank is equipped with the necessary
connectors for:
„Blowing down the steam boiler
„Desalinating the steam boiler
„Thermostatic control of the cooling water
inlet regulator
„Mixed water drain outlet
„Ventilation (vapour extraction)
„Draining (clearing residues)
„Inspection port
Standard values
T.D.S. rate
T.D.S. mass flow rate
Blow-down capacity
Blow-down time
Blow-down mass flow rate
Cooling water temperature
Waste water temperature
Waste water mass flow rate
Boiler water blow-down
temperature
A = 5 %
૷A = ૷FS x A/100 (kg/h)
a = 7.5 kg/s
Ta = 4 s/8h
૷a = a x Ta = 7.5 kg/s x 4 s/8h = 3.75 kg/h
TCW = 15 °C
TWW = 30 °C
૷WW = ૷A + ૷a + ૷CW (kg/h)
Ta (°C), Ta ≈ Ts Ł(pB)
with Ts the saturated steam temperature
as a function of the operating pressure (pB)
from [Tb.2].
Boiler water blow-down
temperature (cooler inlet)
T.D.S. water temperature
Ta/C ≈ ૷(pE/C = 0 bar) ≈ 100 °C
TA (°C);
TA = Ł(pE/D) as a function of the deaerator
steam pressure pE/D from [Appendix Tb.2].
Assumptions: TA = 105 °C for pE/D ≈ 0.21 bar
The mixing cooler is designed to accept all
pressurised and hot waste water that occurs in
the boiler system. This water is depressurised
to atmospheric pressure in the mixing cooler.
The mixing cooler is vented to atmosphere. By
adding cooling water from the untreated water
or softened water network via an inbuilt lance,
the expanded waste water is cooled to a drain
temperature of 30 to 35 °C. For this purpose,
the mixing cooler is equipped with an electrical
cooling water controller. Depending on the
hardness of the raw water, blending of the raw
water with softened water is recommended to
minimise scale formation in the mixing cooler.
However, the blow-down volume entering the mixing cooler (૷a/C) is reduced by the
waste steam volume (expansion amount of steam ૷a/DE):
૷D& ૷D૷D'(
DQGZLWK
૷D'(
Ł'(
[૷D
WKHLQFRPLQJEORZGRZQYROXPHLVGHULYHGIURP
૷D&
૷D[
Ł'(
with ŁDE, the percentage proportion of re-evaporation from [Appendix Tb. 8] as a
function of the difference between the operating pressure (pB) and the atmospheric
expansion operating pressure (pE/C = 0).
Fig. D.7.1.1–1
Mixing cooler
Note
During each shift (8 h), a spontaneous blow-down amount occurs briefly (4 s) of
approx. 7.5 kg/s x 4 s = 30 kg. Assuming an operating pressure of PB = 13 bar, the
amount is reduced to:
Venting via the roof
Cooling water
connection
Desalination/
blow-down
inlet
Cleaning
aperture
Discharge
(waste
water)
< 35 °C
Drain
PD& [ ปNJ
Cooling of this intermittently occurring amount takes place using the constantly
adequately calculated "cold" 30 °C water seal (mW/V) in the mixing cooler according to
the following rough calculation:
P:9ุ
PD&[7D&7::
7::7&:
ุ
[
ุ
OLWUHV
D.7 Thermal equipment
Conclusion
As a consequence, in order to determine the necessary hourly
amount of cold water and the incoming total waste water
volume, only the balance amounts resulting from the continuous
processes need to be determined.
Intermittent blow-down, 2 x per shift (8 h operation), each with 2 s
blow-down time, is recommended to minimise the cooling water
requirement and necessary tank volume for ensuring an adequate
water seal.
Sample determination of tank volumes for mixing coolers
Determination of tank volumes as an indicative approximation,
with assumptions for:
„Fresh steam output ૷ FS
= 12,000 kg/h
„Fresh steam pressure pB
= 13 bar
„Saturated steam temperature Ts
= 195 °C
૷ ૷ [7 7 ૷ [7 7 $
$
&:
::
::
Observe the information specified in chapter D.8.5 concerning
essential straight-through nominal diameters (DN) for ventilation
(vapour line, waste water, cooling water).
૷ D
D&
::
[kg/h]
7 7 &:
[[
&:
[kg/h]
૷CW = 3017.50 kg/h and the total amount of waste water
Standard values
„Required amount of cooling water ૷ CW (kg/h), as a balance
variable (heat and volume balance) for the mixing cooler,
neglecting the amount of expansion steam ૷ a/DE
૷&:
K
::K
&:
(with cpi = constant boiler lye and cooling water) becomes:
૷$[7$7::૷D7D&7::
7::7&:
and the additional input data:
૷&:
૷)6[[[
and the total amount of waste water ૷WW (kg/h) from:
૷:: ૷$૷D૷&: ૷)6[૷&:
૷A = 3621.25 kg/h
derived from standard systems, according to the following
tabular overview, a tank volume of ≈ 600 litres results.
૷$[K
$K
::૷DK
D&K
::
and the general relationship for calculating the media enthalpy
for hi = cpi x ti
૷&:
૷A = 3017.50 + 12,000 x 0.05 +3.75 [kg/h]
>[email protected]
164/165
Fig. D.7.1.1–2
Container volumes - standard systems
System
1
2
3
4
5
6
type
૷ FS
≤ 4.0
> 4 to ≤ 7
> 7 to ≤ 14
> 14 to ≤ 20
> 20 to ≤ 40
> 40 to ≤ 75
WK
6.0
8.0
10.0
13.0
16.0
18.0
20.0
22.0
25.0
„ ૷ FS
„ pB
125/
125/
125/
125/
325/
600/
400 x1450
400 x1450
400 x1450
400 x1450
600x1580
800x1690
325/
325/
325/
600/
1000/
1500/
600x1580
600x1580
600x1580
800x1690
1000x1810
1200x2100
325/
325/
325/
600/
1000/
1500/
600x1580
600x1580
600x1580
800x1690
1000x1810
1200x2100
600/
600/
600/
600/
2000/
1500/
800x1690
800x1690
800x1690
800x1690
1500x2100
1200x2100
600/
600/
600/
600/
2000/
1500/
800x1690
800x1690
800x1690
800x1690
1500x2100
1200x2100
600/
800/
800/
1000/
2000/
2000/
800x1690
900x1750
900x1750
1000x1810
1500x2100
1500x2100
600/
800/
800/
1000/
2000/
2000/
800x1690
900x1750
900x1750
1000x1810
1500x2100
1500x2100
1000/
1000/
1000/
1400/
2400/
2600/
1000x1810
1000x1810
1000x1810
1150x1870
1500x2200
1600x2100
1000/
1000/
1400/
1400/
2400/
2600/
1000x1810
1000x1810
1400x1870
1150x1870
1500x2200
1600x2100
– Fresh steam output
– Fresh steam pressure
„ Numeric
specifications, e.g. xxx/yyy x zzz
xxx = Capacity (litres)
yyy = Container diameter (mm)
zzz = Total height (mm)
D.7 Thermal equipment
Note
For multi-boiler
operation, provision
must be made for the
corresponding selections
similar to single boiler
operation, but with
parallel feed into the
mixing cooler.
D.7.1.2
Lye cooler - function description,
standard values, design
assumptions
Lye, in this instance, refers to the T.D.S.
amount.
Or:
Lye = T.D.S. amount
Example: System type 3
Feeding of (n+1) steam boilers with a total
output ≤ 14 t/h, etc.;
The following rule of thumb applies: (n+1)
always ≤ ૷FS
„For system concepts with boiler output
૷ FS > 20 t/h, consideration would have
to be given, in principle, to the use of an
indirect lye cooling system (for the purpose
of heat recovery) upstream of the mixing
cooler inlet. This would be conditional,
however, on a consistently (continuously)
available amount of top-up feedwater
(softened water quantity) as a so-called
heat sink. The cooling water demand
(cooling water costs) could be minimised
A cost-benefit analysis would deliver
appropriate verification in this instance.
Balance sheet approach
The required lye cooling capacity Q̇L/C
(see also Fig. D.7.1.1-3)
4
ɘ /& ૷$[FS[7$(7$$
૷::[FS[7::$7::(LQN:
4
ɘ /& ૷)6[[FS[7$(7$$
[[[
4
ɘ /& N:
and cooling water savings (Δ ૷CW) from:
ෙ૷&: ૷$[7$(7$$
7::7&:
[[
NJK
plus an expected payback period (Amo) of:
$PR &RROHUFRVWVN/&
&RROLQJZDWHUFRVWVෙN&:
LQ\HDUV
with:
„Cooler costs kL/C ≈ €3500 (plate heat
exchanger including pipework and valves)
„Cooling water costs ΔkCW = €3.50/t and
3000 kg/h ฬ 3t (Δ૷cW ) plus annual hours
run b = 1760 h (8 h/day x 220 days/year)
$PR ೼[D
K[WK[೼W
Dฬ\HDUV
Note
In terms of procedure, however, continuous
throughput of softened water through the
cooler and/or an alternative available "heat sink"
on the customer side (e.g. domestic heating
water) must be assured here.
166/167
Fig. D.7.1.1–3
Schematic diagram of lye cooler
a)
Soft water outlet
Lye cooler
7::$
Lye outlet
7$$ปr&
૷$
7$(ปr&
Lye inlet
૷ ::ปNJK
7::(ปr&
Soft water inlet
Lye cooler
System
System
lye cooler
mixing cooler
cp - specific heat for lye and softened water ~ 0.001163 kWh/kgK
a)
An additional check must be made
in the actual application case as to
whether any temperature limiting
measures (temperature control with
limiter as a watchdog function) are
required for the softened water
leaving the cooler.
D.7 Thermal equipment
Fig. D.7.2.1–1 T.D.S. expander
D.7.2 T.D.S. expander
Expansion steam outlet
(if applicable, feed into thermal deaerator)
T.D.S. lye
T.D.S. lye outlet
(mixing cooler feed)
The amount of heat
.
(Qiye) "withdrawn"
as part of the boiler
desalination is recovered
by feeding the expansion
steam into the thermal
feedwater deaeration
system. With the heat
balance assumption:
.
.
Qlye = Qexpansion steam
Function description, standard
values, sizing assumptions
The T.D.S. expander is designed to accept the
boiler desalination fluid and to depressurise
it to a level of 0.5 bar. The expansion steam
is utilised as heating steam in the deaeration
system. The residual lye is fed into the mixing
cooler.
Inlet
Note
D.7.2.1
No separate foundations are required for
installing the expander. The floor on site needs
only to be level and capable of bearing the
relevant load.
The expander (tank) is equipped with the
necessary connectors for:
„T.D.S. inlet, originating from the
steam boiler
„T.D.S. outlet, to the mixing cooler
connection
„Expanded steam outlet, to the thermal
deaeration connection
„Connection for safety valve (optional),
only when feeding expanded steam into
unprotected systems
„Draining (removing residues)
T.D.S. expander - standard values:
„T.D.S. rate
A = 5 %
„T.D.S. mass
flow rate
૷A = ૷ FS x A/100 [kg/h]
„T.D.S. water temperature TA (°C) where
TA = Ł(pE/D) is a function of the expansion
steam positive pressure from (Tb. 2),
TA = 105 °C in this case for pE/D ≈ 0.21 bar
„Expansion steam output - ૷ D/E [kg/h], as a
balance variable (heat and volume balance)
for the lye expander from the enthalpy
values (as a function of temperature and
pressure according to Tb. 2) for:
T.D.S. inlet
h'A/E = Ł(Ts - saturated steam temperature)
[kWh/kg]
T.D.S. outlet
h'A/A = Ł(pE/D)
Feedwater enthalpy
h' fw [kWh/kg]
Expansion steam
h''D/E = Ł(pE/D) [kWh/kg]
a)
૷'(
૷$[K
$(K
$$
K
'(K
$$
NJK
168/169
and
b)
૷)6[$[K
$(K
$$
૷'(
K
'(K
$$
and the amount of lye ૷L/A from the
expander
૷/$ ૷)6[$૷'(
>[email protected]
Sample calculation
Fresh steam output
૷FS = 12,000 kg/h
Fresh steam pressure
pB = 13 bar
Saturated steam temperature
from [Tb. 2]
Ts = 195 °C
Deaerator steam positive
pressure as expansion
steam pressure
pE/D ≈ 0.21 bar
Enthalpy values as f = pB, pE/D from [Tb. 2]
h'A/E
= Ł(pB)
= 0.230 kWh/kg
ฬ830 kJ/kg
h'A/A
= Ł(pE/D) = 0.122 kWh/kg
ฬ439 kJ/kg
h''D/E
= Ł(pE/D) = 0.745 kWh/kg
ฬ 2683 kJ/kg
૷'(
૷)6[$[K
$(K
$$
NJK[[N:KNJ
K
'(K
$$
N:KNJ
ปNJK
and
૷/$ ૷)6[$૷'( NJK[NJK
૷/$ ปNJK
a)
= An estimation is also possible
here from the enclosed diagram
Tb.6 with approx. 17.5 % of ૷A.
D.7 Thermal equipment
„For output ranges ≤ 14 t/h, a similar
selection is possible from the Viessmann
datasheets
Container volumes
„As an indicative approximation (derived
from conventional Viessmann systems)
according to tabular overview for steam
boiler outputs > 14 t/h to ≤ 75 t/h
Fig. D.7.2.1–2 ૷FS - steam boiler output > 14,000 kg/h to ื 20,000 kg/h
Note
For multi-boiler
operation, provision
should be made for
the corresponding
selections similar to
single boiler operation,
but with parallel feed
into the expander, as
stated previously for the
mixing cooler.
pB-
Lye
Steam
Steam operating
Aa)
DNlye
DNsteam
L xW
H
ØD
Capacitya)
pressure
૷D/Ea)
Connections
Dimensions
kg/h
kg/h
inlet/outlet
outlet
mm
mm
mm
litres
6.0
1000
116
20/25
65
950 x 750
1700
500
100
8.0
1000
135
20/25
65
1050 x 850
1800
600
320
10.0
1000
153
20/25
80
1050 x 850
1800
600
320
13.0
1000
173
20/25
80
1050 x 850
1800
600
320
16.0
1000
193
20/25
80
1050 x 850
2400
600
450
18.0
1000
204
20/25
80
1050 x 850
2400
600
450
20.0
1000
214
20/25
100
1050 x 850
2400
600
450
22.0
1000
223
20/25
100
1050 x 850
2400
600
450
25.0
1000
238
20/25
100
1050 x 850
2400
600
450
Fig. D.7.2.1–3 ૷FS - steam boiler output > 20,000 kg/h to ื 40,000 kg/h
pB-
Lye
Steam
Steam operating
Ab)
DNlye
DNsteam
L xW
H
ØD
Capacityb)
pressure
૷D/Eb)
Connections
Dimensions
kg/h
kg/h
Inlet/Outlet
Outlet
mm
mm
mm
litres
6.0
2000
231
20/32
100
1050 x 850
2400
600
450
8.0
2000
270
20/32
100
1050 x 850
2400
600
450
10.0
2000
306
20/32
100
1050 x 850
2400
600
450
13.0
2000
347
20/32
100
1050 x 850
2400
600
450
16.0
2000
386
20/32
125
1250 x 900
2600
750
800
18.0
2000
408
20/32
125
1250 x 900
2600
750
800
20.0
2000
427
20/32
125
1250 x 900
2600
750
800
22.0
2000
446
20/32
125
1250 x 900
2600
750
800
25.0
2000
475
20/32
125
1250 x 900
2600
750
800
Fig. D.7.2.1–4 ૷FS - steam boiler output > 40,000 kg/h to ื 75,000 kg/h
a)
With reference to ૷FS(max) = 20,000 kg/h
b)
With reference to ૷FS(max) = 40,000 kg/h
c)
With reference to ૷FS(max) = 75,000 kg/h
pB-
Lye
Steam
Steam operating
Ac)
DNlye
DNsteam
L xW
H
ØD
Capacityc)
pressure
૷D/Ec)
Connections
Dimensions
kg/h
kg/h
Inlet/Outlet
Outlet
mm
mm
mm
litres
6.0
3750
433
32/50
125
1250 x 900
2600
750
800
8.0
3750
506
32/50
150
1250 x 900
2600
750
800
10.0
3750
572
32/50
150
1250 x 900
2600
750
800
13.0
3750
650
32/50
150
1250 x 900
2600
750
800
16.0
3750
723
32/50
150
1500 x 1250
2400
1000
1200
18.0
3750
766
32/50
200
1500 x 1250
2400
1000
1200
20.0
3750
801
32/50
200
1500 x 1250
2400
1000
1200
22.0
3750
837
32/50
200
1500 x 1250
2600
1000
1400
25.0
3750
891
32/50
200
1500 x 1250
2600
1000
1400
170/171
D.7.3
D.7.3.1
Exhaust vapour condenser
The extracted gases (O2, CO2) are removed
into the open air via the ventilation duct that
must terminate outside the building (on the
roof). The condensate, on the other hand,
is discarded. In the case of multi-boiler
systems with a common thermal water
treatment system (TWT), installation of a
motorised control valve in the exhaust vapour
pipe upstream of the condenser inlet is
recommended to further minimise the amount
of exhaust vapour.
Function description, standard
values, sizing assumptions
With reference to the specifications in chapter
C.8.3, the following section provides more
detailed information on function and sizing.
By condensing the exhaust vapours, in
conjunction with subsequent further cooling
of the vapour condensate, the "exhaust vapour
waste heat" energy can be returned to the
system. A partial feedwater flow upstream
of the deaerator inlet would be employed in
this instance as the required heat sink, with
appropriate process switching (see Appendix
A1). The energy-specific context is illustrated
in the following temperature/heating surface
diagram (Fig. D.7.3.1-1).
The control valve would have to be controlled
as a function of the operational loada) (see
Fig. D.7.3.1-2) by the control equipment of the
steam boiler system (in this case, the PLC programmable logic controller).
0HGLDWHPSHUDWXUHr&
Fig. D.7.3.1–1 Temperature/heating surface diagram
Exhaust vapour
Exhaust vapour
condensation
supercooling
Q̇V/C
Q̇V/U
Δ7ODUJH
TS/V
TU/V
Tfw/A
Partia
l flow
Feedw
ater p
ΔT(small)
Q̇V
rehea
ter
Tfw/E
+HDWLQJVXUIDFHPt
([KDXVWYDSRXUFRQGHQVHU
TS/V
Tfw/E
Tfw/A
TU/V
Saturated steam temperature,
exhaust vapours
Feedwater inlet temperature
Feedwater outlet temperature
Exhaust vapour condensate
outlet temperature
a)
In addition to the operational load,
continuous hooking up of arising
O2 values (O2 test in the feedwater
line) would be optimal (see also
chapter D.4.5 Water analysis).
D.7 Thermal equipment
Fig. D.7.3.1–2
Schematic diagram of exhaust vapour condenser operation
Vent
(O2 / CO2)
9&
૷fw
સCON
Exhaust vapour condenser
Motorised control valve
Exhaust vapour steam
Feedwater partial flow
Vapour condensate
Sight glass
Steam trap
Ventilation to the outside (via roof)
Deaerator dome
SG
૷S/V
M-CVb)
VC
M-CV
૷S/V
૷fw
સCON
SG
ST
Vent
D
M
ST
D
&RQGHQVDWHGUDLQLQJLQWRWKHFRROLQJ
DQGH[SDQVLRQSLWWREHSURYLGHGRQ
VLWHRQWKHZDVWHZDWHUVLGH
Further standard values and information to be
considered for sizing:
„ Amount of exhaust vapour steam ૷ S/V
calculated from:
૷69ปŁ9P[૷&21૷DGGIZ
Ł%P૷)6[$>[email protected]
with the variables:
૷CON Condensate return feed into the
deaerator
૷add/fw Additional amount of feedwater as
amount let into the deaerator
Fresh steam output
૷FS
A
T.D.S. rate in (%)
ŁV/m
Average factor for calculating the
minimum amount of exhaust vapour
steam
b)
A 5 to 10 % "open" position for
the M-CV must be ensured by
means of control technology via
an appropriate end position locking
mechanism.
Note
In practice, sufficient accuracy is provided by
ŁV/m = 0.005 to 0.01 [-], whereby "higher" values
must be assumed for "lower" amounts of
return condensate (< 40 %).
„For reasons of energy management,
temperature differentials across the
condenser (heat exchanger) should be
selected:
ෙ7VPDOO 7Q97IZ(ปWR.
ෙ7ODUJH 7V97IZ$ปุ.
„Pressure losses (steam side) condenser ≤ pV/E
„Pressure losses (water side) condenser ≤ 0.5 bar
„Heat output - Q̇V of the exhaust vapour
condenser from the condenser heat
balance
4
ɘ 9 4
ɘ 9&4
ɘ 98 ૷IZ[F3[7IZ$7IZ(
RU
4
ɘ 9 ૷69U9F3[769789
where
cP - Specific heat for condensate and
feedwater
~ 4.19 kJ/kg K and/or
0.001163 kWh/kg K
rV - Latent heat of condensation - exhaust
vapour steam rV = (h''S/V - h'C/V) as a
function of deaerator pressure (pV/E) from
[Tb. 2] and/or determined with:
h''S/V - exhaust vapour steam
enthalpy = Ł(pV/E)
and
h'C/V - exhaust vapour condensate
enthalpy = Ł(pV/E)
172/173
1st sample calculation
3rd sample calculation
Calculation of Q̇V in (kW):
Potential savings - payback period
„T.D.S. rate A = 5 %
„Fuel - natural gas (E) with Hi = 10.35 kWh/Nm³
„Fresh steam output ૷ FS = 12,000 kg/h
„Mean boiler efficiency Š K(M) ≈ 94.75 %
„Factor for minimum amount of vapour
(according to datasheet and ECO operation)
૷ V/M ≈ 0.0075 (selected)
૷ S/V = 0.0075 x [12,000 (1+5/100)]= 94.5 kg/h
„Composite fuel price k FP = € 0.414/Nm³
„Annual full-load hours b = 6000 h (assumption)
„Deaerator positive pressure p B/D = 0.21 bar
„T S/V = Ł(pB/D) from (Tb. 2) = 105 °C
„r V = Ł(pB/D) from (Tb. 2) = 0.623 kWh/kg
.) ɘ 9[N)[E
4
+L[Š .0
N:[೼[K
1P
N:K[
1P
„cp = 0.001163 kWh/kgK
Annual cost savings K F = €17,335/a
„Feedwater temperature - Tfw/E = 15 °C
„Temperature differential - ΔTsmall = 3 K (selected)
(T U/V = 15 + 3 = 18 °C)
Q̇V = 94.5 [0.623 + 0.001163 (105 - 18)] = 68.44 kW
2nd sample calculation
Calculation of the required feedwater partial flow -
With estimateda) additional expenditure (Kcon)
for the condenser of €11,500, including
pipework, valves and exhaust vapour steam
output controller, amortisation can be expected
within a period (AK) of
AK = Kcon / KF = €11,500/a / €17,335/a =
0.66 years.
૷fw in (kg/h)
„Temperature differential - ΔT large = 20 K (selected)
„Tfw/A = 105 - 20 = 85 °C
૷IZ
N:[NJ[.
NJK
N:K[.
a)
Required specification by obtaining
specific quotations.
D.7 Thermal equipment
D.7.4
D.7.4.1
Feedwater cooler
Function description, standard
values, sizing assumptions
With the feedwater cooler, the feedwater
entering the economiser (ECO) can be cooled
down to feedwater temperatures (Tfw/C-O) below
the deaerator saturation temperature (TS/D).
The feedwater outlet temperature from the
feedwater cooler would have to be selected
accordingly (see Fig. D.2.3.3-1), however,
taking account of a permissible further cooling
of the flue gases leaving the ECO close to the
flue gas dew-point temperature.
In the following text, reference is made
to ECO types 100/200, while observing
the thermodynamic data specified in the
Vitomax 200-HS datasheets.
Soldered plate heat exchangers made of
stainless steel are recommended for the
feedwater cooler. Process-related integration
(circuit) into the overall system concept is
illustrated in the enclosed schematic process
diagram (see Appendix A1).
Calculation of Tfw/C-O and the associated
additional ECO output Q̇ECO in terms of heat
recovered:
Assumptions:
The feedwater outlet temperature
Tfw/O-ECO remains the same for each load case
considered (see Fig. D.7.4.1-2 Temperature/
heating surface diagram).
With reference to the notes for calculating the
ECO heating output Q̇ECO (see chapter D.2.3.1),
the additional output ΔQ̇ECO due to reduction of
the feedwater inlet temperature into the ECO
is determined similarly from the statement
equation:
174/175
Statement equation
With assumptions and values for:
Fresh steam output
Operating pressure
Factor RECO = ŁSB) for
૷FS = 12,000 kg/h
pB = 12 bar
RECO/200 = 1.044;
RECO/100 = 1.067
Tfw/ECO-Standard = 102 °C
Feedwater inlet temperature into the ECO
(standard design temperature)
Flue gas density
Specific heat - feedwater
T.D.S. rate
Flue gas outlet temperature for
(design temperature = Ł(PB)
and 100 % boiler load)
Permissible flue gas temperature reduction
for HEL operation
for natural gas (E) operation
ෙ4
ɘ (&2
̖FG = 1.345 kg/Nm³
cP = 0.001163 kWh/KgK
A = 5 %
TFG/ECO-200 ≈ 132 °C
TFG/ECO-100 ≈ 177 °C
TFG/ECO-reduced = 125 °C
TFG/ECO-reduced = 115 °C
7)*(&2VWDQGDUG7)*(&2UHGXFHG
ෙ4
ɘ (&2 ૷)6[
$
[
૷)6[5
̖)*
[F3[7IZ(&2VWDQGDUG7IZ2&
>N:@
„where: ΔT FG = T FG/ECO-standard - T FG/ECO-reduced [°C],
„and: ૷fw = ૷ FS x (1 + A/100) [kg/h]
„and the equation for the reduced feedwater temperature:
7)*(&2VWDQGDUG7)*(&2UHGXFHG
7IZ2& 7IZ(&2VWDQGDUG
[
5(&2
̖)*
$[F3
ෙ4
ɘ (&2
ෙ7)*
[
૷)6[5
̖)*
૷IZ[F3[7IZ(&2VWDQGDUG7IZ2&>N:@
the following results are yielded, summarised in the form of a table of values (see Fig. D.7.4.1-1).
D.7 Thermal equipment
Fig. D.7.4.1–1 Table of values
Value table:
Type ECO-200
TFG/ECO-standard (°C)
TFG/ECO-reduced (°C)
Tfw/ECO (ECO design) (°C)
Type ECO-100
132
132
177
177
HEL
Natural gas (E)
132
HEL
Natural gas (E)
177
125
115
100
125
115
100
102
102
102
102
102
102
Permissible Tfw/O-C (°C)
100.22
97.68
93.87
88.79
86.25
82.44
Temperature differentiala) (TFG/ECO-reduced - Tfw/O-C) (K)
24.78
17.32
6.131a)
36.21
28.75
17.56
ΔQ̇
26.08
63.30
119.14
193.57
230.79
286.63
132.2
132.5
132.5
121.5
121.5
121.5
ECO
(kW)
Tfw/O-ECO (for standard design) (°C)
In the following temperature/heating surface
diagram, the results from the table of values
are presented by the ECO-200‘ as an example:
Note
Fig. D.7.4.1–2 Temperature/heating surface diagram
The figures in [ ],
apply in addition to the
ECO 100.
0HGLDWHPSHUDWXUHr&
(&2ᚐXHJDVLQOHW
>@
VWDQGDUG
Δ7ODUJH
[1]
>@
(&2IHHGZDWHU
[2]
+(/
)OXHJDV
QDWXUDOJDV
RXWOHW
RXWOHW
Δ7VPDOO
7IZ2(&2
VWDQGDUG
[1]
[2]
102 (standard)
100.27 (HEL) [88.79]
)HHGZDWHU
LQOHW
97.68 (natural gas)
[86.25]
+HDWLQJVXUIDFHPt(&2
$(&2
„ΔT(large)
„ΔT(small)
„1) ΔQ̇ECO
„2) ΔQ̇ECO
a) The temperature differentials
should not fall below ≤ 10 K
(in respect of an optimum
ECO heating surface size).
Temperature differential between
flue gas inlet and water outlet
Temperature differential between
flue gas outlet and water inlet
HEL operation
Natural gas (E) operation
176/177
Cost of natural gas (E)a) kF(E)
≈ €0.414/Nm³
Feedwater cooler sizing
The required cooling capacity - Q̇fw/C (in kW)
and the ensuing additional feedwater outlet
temperature/cooler - Tadd/fw/O-C are calculated
from the statement equations:
Cost of fuel oil (HEL)a)
kF(HEL)
≈ €0.65/kg
4
ɘ IZ& ૷DGGIZ[F3[7DGGIZ2&7DGGIZ,& Annual full-load hours
b
≈ 6000 h/a
Costs saved - potential savings (kF):
With values for:
૷IZ[F3[7V,7IZ2&LQ>N:@
the equation:
.)
where
ɘ
Δ4
[N)[E
(&2
૷IZ ૷)6[
+L[ǹ .0
$
LQNJK
yields the expected minimum annual savings for
HEL operation:
and
[[
.)(/
[
૷DGGIZ ૷)6[
ป೼D
$
૷&21LQNJK
and for natural gas operation:
the required cooling capacity [in kW] from:
[[
.)(
[
4
ɘ IZ& ૷)6[$[F3[7V,7IZ2&LQ>N:@
ป೼D
and the expected additional feedwater outlet
temperature/cooler from:
4
ɘ
IZ&
7DGGIZ2&
Fig. D.7.4.1–3
[૷)6[$૷&21] 7DGGIZ2&
[F3
Schematic diagram of feedwater cooler
Additional feedwater
outlet temp./cooler
Tadd/fw/O-C
Feedwater
Feedwater
outlet temp./
૷fw
cooler
Tfw/O-C
Feedwater inlet temp.
TS/D (as a function of the
deaerator pressure pB/D)
Additional
Additional feedwater
feedwater
inlet temp./cooler
૷add/fw
Tadd/fw/I-C
a) Current prices must be
determined here in each case
(e.g. www.heizoelboerse.de;
www.carmen-ev.de).
D.7 Thermal equipment
2nd sample calculation
1st sample calculation
With the results from the table of values and the
Ktot = ΔK ECO + Kcooler (€)
additional assumptions for:
= 23.94 x ΔQ̇ECO + 2.86 x Q̇fw/C + €13,258
T S/D = Ł(pB/D = 0.2 bar)
and:
= 105 °C
A = Ktot /K B [a]
Amount of condensate ૷ CON ≈ 0.5 x ૷ FS
= 6000 kg/h
Additional feedwater inlet
temperature/cooler - Tadd/fw/I-C
for HEL operation:
Ktot = 23.94 x 26.08 + 2.86 x 70.04 + 13,258 ≈
= 15 °C
€14,083
A = 14,083/9021 ≈ 1.56 years
the required cooling capacities for
HEL operation:
for natural gas (E) operation:
Q̇fw/C = 12,000 x (1+ 5/100) x 0.001163 x
(105 - 100.22) = 70.04 kW
Ktot = 23.94 x 63.30 + 2.86 x 108.51 + 13,258 ≈
€15,084
Natural gas operation
A = 15,084/16,034 ≈ 0.94 years
Q̇fw/K = 12,000 x (1+ 5/100) x 0.001163 x
(105 - 97.68) = 108.51 kW
and the respective expected additional feedwater
outlet temperature/cooler of:
Note
for HEL operation:
Tadd/fw/O-C =
70.04
[(1200 x (1 + 5/100) - 6000)] x 0.001163
+ 15
= 24.10 °C
for natural gas (E) operation:
Tadd/fw/O-C =
108.51
(1200 x (1 + 5/100) - 6000) x 0.001163
+ 15
= 29.13 °C
Payback periods
In principle, the total expected costs (Ktot) for
the feedwater cooler, including pipework and
valves, but excluding the expected costs for
any necessary enlargement of ECO heating
surfaces, must be prepared via a specific
manufacturer's quotation, as a function of each
calculated ECO "additional output" - ΔQ̇ECO.
For the time being, the previously cited ECO
cost function could be helpful with
ΔKECOa) ≈ 11,500 + 23.94 x ΔQ̇ECO (€) and for the
feedwater cooler with
Kcooler ≈ 1758 + 2.86 x Q̇fw/C (€) (value range
Q̇fw/C ≥ 50 to ≤ 900 kW).
Regarding a)
The assumption of rising costs can be
dismissed if the manufacturer ensures an
increased mean logarithmic temperature
differential
ΔTm = (ΔTlarge - ΔTsmall) / (ᔉΔTlarge / ΔTsmall) in [K]
over the ECO heating surface that then
remains constant.
The feedwater temperatures for ECO inlet
and outlet would have to change in line with
requirements compared with the data in
the table of values. However, the feedwater
inlet temperatures into the ECO should
here not fall below 85 °C if at all possible.
In line with the modified selection, the
feedwater outlet temperature would also
be subject to a downward correction.
However, a precise determination can
only be made in conjunction with the
respective thermodynamic ECO sizing and
construction on request at:
[email protected]
178/179
Conclusion - recommendations
„Most effective use of a feedwater cooler is
made with the selected ECO type 200 and
natural gas (E) operation
„The available "utilisation potential" is much
greater with ECO type 100 than type 200
and therefore also retains considerable
reserve capacity, preferably for HEL
operation
„The thermodynamically balanced
feedwater cooler outlet temperatures
between 83 and 89 °C for the ECO 100
and 94 to 100°C for the ECO 200 (see
table of values Fig. D.7.4.1-1) should be
selected approx. 10 K higher for HEL
operation, to ensure that the temperature
does not fall below the dew point. The
standard feedwater outlet temperature
from the ECO 100 would also rise in line
with this increase
„System concepts should focus on
maximised heat recovery from the flue
gas, for example with ECO types 200/100
Additional use of feedwater coolers
should therefore only be regarded as an
supplementary optimisation version in the
case of justifiable expenditure and payback
periods ≤ 1 year.
Check the application case as to whether any
temperature limiting measures (temperature
control with limiter as a watchdog function)
are required for the softened water leaving the
cooler.
D.7 Thermal equipment
Fig. D.7.5.1–1 Workplace for evaluating water samples taken from feedwater and boiler water
D.7.5
D.7.5.1
Sampling cooler
Notes on installation and
taking samples
According to regulations (TD 611 Clause 5 and
EN 12953 Part 10), feedwater and boiler water
must be monitored continuously.
The samples described here are taken
intermittently and subjected to an appropriate
laboratory test (on site in the boiler installation
room and/or externally in company laboratories
assigned to the steam boiler system). Before
they are taken, however, samples must be
cooled down to ≤ 30 °C.
The Viessmann sampling cooler can be
employed, in the case of an appropriately
designed circuit combination, both for the
cooling of boiler water and the cooling of
feedwater. The necessary cooling water
must be taken from the corporate drinking
water supply according to the rules of good
engineering practice (see proposed installation
in the installation instructions).
180/181
Key
BW
FW
DW
WD
Fig. D.7.5.1–1
Boiler water (if applicable, taken from
the discharge pipe - reflection water
level in the steam boiler)
Feedwater (taken from the feedwater
tank and/or feedwater pipe)
Drinking water (cold water) - water
supply, customer side (R 1/8 to
R 1/2 = PN6)
Water drain, customer side (R 3/4 to
R 1) discharge into main system
Schematic diagram of sampling cooler
2
BW
FW
1.2
1
1 Sample cooler with
1.1 Drain outlet
1.2 Temperature display (planned,
recommended on site)
2 Shut-off valve
3 Non-return valve
4 Shut-off valve (with drain connector)
1.1
2
WD
3
4
WD
Document the results of the determined
analysis values in the boiler book.
Monitoring takes place intermittently at
a frequency of no less than 1x per 8 h
operating time.
However, for system operation according to
TRD 604 Sheet 1 (operation without constant
supervision - BosB - here specifically for
BosB 72 h), continuous monitoring
(see chapter D.4.5 - Water analysis) is
recommended.
Install the cooler as close as possible to the
sampling point.
Suitable sampling tanks are:
Erlenmeyer flasks (e.g. in the case of
immediate laboratory examination) and/or
glass-stoppered glass bottles with a capacity
of approx. 1 litre each.
Analyses values to be documented:
„pH value
„Residual hardness
„p value (for determining the free alkalinity)
„m value (for determining the total alkalinity)
„Phosphate and
„Sulphide
For boiler water and boiler feedwater
requirements, see Appendix A.3.
DW
D.8 Pipework
Pipework
Within the scope of this manual, the intention is to provide information for
selected main pipes (see chapter C.9) for planning purposes.
Note
National regulations and
relevant standards must
be observed.
The engineering process requires close
collaboration between the pipework
manufacturer and the responsible monitoring/
approval authority in conjunction with the
subsequent operator.
A range of information and calculations
provided can also be applied analogously to
pipes not mentioned here for transportation
of liquid and gaseous flow media. The
pipework considered here is restricted to the
steam boiler room and a perimeter extending
1 m beyond.
182/183
D.8.1
Note
Pipework
D.8.1.1
Dimensions and weights
for seamless and welded
steel pipes are specified
in DIN EN 10220 for pipe
series 1 to 3. In principle,
the pipe dimensions
of pipe series 1 are
recommended.
All accessories (fittings,
flanges etc.) required
for building a pipeline
are available for pipe
series 1. Not all standard
components are
available for pipe series 2
and there are hardly any
standard accessories for
pipe series 3.
Nominal diameters - DN
The nominal diameter (abbreviation: DN) is
an index used in pipework systems as an
identifying parameter for parts that are suited
to one another.
In accordance with the following table,
nominal diameters have no units and must not
not be used as dimensions, since they only
correspond in part to the internal diameter of
pipework components.
The internal diameters can exhibit differences
compared with the indices for nominal
diameter depending on the wall-thickness used
in a particular design, as the external diameters
are generally specified out of consideration for
the manufacturing process.
Extract from nominal diameter (DN)
classification of pipes, based on DIN EN 1092-1
Fig. D.8.1.1–1
Nominal diameters (DN) - extract
DN 10 (17.2)
DN 40 (48.3)
DN 125 (139.7)
DN 350 (355.6)
DN 700 (711)
DN 1400 (1420)
DN 15 (21.3)
DN 50 (60.3)
DN 150 (168.3)
DN 400 (406.4)
DN 800 (813)
DN 1600 (1620)
DN 20 (26.9)
DN 65 (76.1)
DN 200 (219.1)
DN 450 (457)
DN 900 (914)
DN 1800 (1820)
DN 25 (33.7)
DN 80 (88.9)
DN 250 (273)
DN 500 (508)
DN 1000 (1016)
DN 2000 (2020)
DN 32 (42.4)
DN 100 (114.3)
DN 300 (323.9)
DN 600 (610)
DN 1200 (1220)
---
Note: Values in brackets are the outer pipe connection diameters (mm)
D.8 Pipework
D.8.1.2
Pressure ratings - PN
The nominal pressure of pipelines and
components (pipes, flanges, fittings, valves
etc.) is the identifier for a pressure rating that
classifies parts of a similar design and identical
connection dimensions. The pressure ratings
are classified according to standard numbers
and listed in the following table.
Extract from pressure rating (PN) of pipes,
based on DIN EN 1092-1
Fig. D.8.1.2–1
Nominal diameters (DN) - extract
PN 2.5
PN 25
PN 160
PN 250
PN 6
PN 40
PN 10
PN 63
PN 320
PN 16
PN 100
PN 400
The nominal pressure (PN) = maximum
permissible positive pressure (in bar) at the
reference temperature T = 20 °C.
a)
Minimum yield strengths
can be taken from standards
DIN EN 10216-2/10217-2 for pipes
and DIN EN 1092-1 in addition for
castings, forgings and hot-rolled
products.
Notes
In accordance with DIN EN 1092-1, the
selected nominal pressure must always satisfy
the condition PN ≥ PD x (RP0.2(20°C) / RP0.2(Toper.))
where
PD
design pressure (calculation
pressure = secure operating
pressure) of the component (pipes,
flanges etc.) in [bar] and
Ra)P0.2 the minimum yield strength at
room temperatures (RP0.2 (20°)) and at
calculation temperature or operating
temperature (RP0.2 (Toper.)) respectively.
The maximum permissible pressure (pD)
calculated at the operating temperature (Toper.)
must not exceed a maximum permissible
pressure assigned to the PN rating.
For calculation or operating temperatures (Toper.)
of -10 °C to 120 °C, the specified condition can
be approximated for ferrous materials with
PN ≈ PD.
184/185
D.8.1.3 Test pressure (Pp) with reference
to Pressure Equipment Directive
The pipes, valves and assemblies
(hereinafter referred to as pressure equipment)
must correspond to the test pressures
according to the Pressure Equipment Directive
97/23/EC. If the test pressures according to
the Pressure Equipment Directive are higher
than the permissible test pressures for the
valves, valves must be selected from the next
higher nominal pressure rating (see chapter
D.8.1.2). Pressure equipment is subject
to a final inspection. For this purpose, the
acceptance process for pressure equipment
must include a pressure strength test in the
form of a hydrostatic pressure test with a
minimum test pressure of Pp ≈ 1.43 x PD.
Notes
If the hydrostatic test is detrimental or
impracticable, alternative non-destructive tests
must be coordinated in consultation with the
customer and the local approved monitoring
body, depending on established categories I,
II and III.
Assigning the pipework systems to the
individual categories is carried out subject to
product of (PD x DN) according to diagrams 6
and 7 (Appendix II) of the Pressure Equipment
Directive, whereby natural gas (E) is assigned
to fluid group 1 and the remaining media to
fluid group 2.
The selection and assignment of modules
must be made in agreement between the
system installer, the customer and the
designated body. Exceptions are pipelines
(pressure equipment) that can be classified
below Category I. This type of pressure
equipment need only meet the requirement of
good engineering practice in respect of design
and production.
Conventions regarding
inspection obligations and recurring
inspections of the pipework must be specified
accordingly, in conjunction with overall system
acceptance, on the basis of the [German]
Health & Safety at Work Act (BetrSichV),
between the installer of the pipework, the
customer and the designated body.
The quality of the pipework system and
system documentation must be designed
in such a way that the maximum intervals
(5 years) are easily complied with.
The Roman numerals for the categories
correspond to the module categories to be
selected accordingly for the pipelines, such as:
Category I
Module A
Category II
Modules A1, D1 and/or E1
Category III
Modules B1+D, B1+F, B+E,
B+C1 and/or H
Fig. D.8.1.1–1
Module categories
Modules A, A1
Internal production control for A, supplemented with monitoring by the designated body for A1
Module B
EC type examination by the designated body, with examination of qualifications of the assembly and
NDT personnel
Module B1
Similar to module B, but without testing of a prototype
Module C1
Conformity to type; the designated body monitors production and inspection at the manufacturer
on a random sample basis
Module F
EC individual examination by the designated body as a basis for issuing conformity
Modules D,E,H
Aside from the classic product tests for verifying conformity, additional introduction of QA systems
and their appraisal by the designated body
D.8 Pipework
D.8.1.4
Operating temperatures (Td) and
operating pressures (PD)
For the "hot-running" pipe complex, the
following must be expected and/or selected in
reality subject to media:
Fig. D.8.1.4–1
PN6
Pipe operating temperatures
PD (bar)
Steam1
Lye2
Lye3
Exhaust steam
Condensate5
Condensate
Feedwater
(°C)
Blow-down
Blow-down
vapours4
(sealed unvented)
(open) (°C)
(°C)
(°C)
(°C)
(°C)
(°C)
95
110
16
0.5
111
111
111
16
1.0
120
120
120
16
2.0
134
134
134
16
3.0
148
148
148
16
4.0
152
152
152
16
5.0
159
159
159
16
6.0
165
165
--
16
8.0
175
175
16
10.0
184
184
--
25
13.0
195
195
--
25
16.0
204
204
--
25
18.0
210
210
--
40
20.0
215
215
--
40
22.0
220
220
--
40
25.0
226
226
--
Key
1 Required supplement (ΔTü) for
superheating with Δtü ≈ 50 K (as standard)
2 Temperatures before expansion
3 Temperatures after expansion to
pD ~ 0.5 bar
4 Expanded to around atmospheric pressure
5 Assuming pDmax ~ 5.0 bar
6 Nominal pressure ratings based on the
steam boiler used in the initial analysis. An
additional check in accordance with chapter
D.8.1.2 is nevertheless recommended
110
110
--
186/187
D.8.1.5
Identification of pipes
D.8.1.6
Pipelines are identified according to the fluid
conveyed according to DIN 2403. This includes
pipes and their connections, valves and fittings,
as well as thermal insulation. The fluids are
divided into 10 groups based on their general
properties; the colours for the groups being
defined (according to RAL colour register) in
the following table. As a separate identification
of flammability, the tops of signs for groups 4
and 8 are coloured red (RAL 3000).
Flow diagrams, graphic symbols
for pipe and equipment design,
and identification systems
The flow diagram (system scheme, flow
scheme, heat flow chart, pipework diagram
etc.) should render, with the help of pictorial
symbols and graphic characters, a simplified
graphic representation of the structure and
function of the system. It is designed to
provide all those involved with the system, e.g.
customer, manufacturer, authority, designated
body etc. with a clear understanding.
The layout and representation must be
adapted liberally to fit the intended purpose
(steam boiler system). The basis is provided
by the relevant graphic characters and
pictorial symbols according to DIN 2481,
2429, 19227 and DIN 28004 (see also design
and representation in Appendix [A1]). The
components indicated in the flow diagram
(steam boiler with ancillary systems, pipes
with add-on and built-in parts, including
indicated control components) should
additionally be provided with a consistent
identification system throughout.
A consistent identification system allows the
aforementioned parties involved to address
each individual part of the steam generation
system in a clear and consistent manner.
Fig. D.8.1.5–1
Identification of pipes
Fluid
Group
Colour
Water
1
green
RAL 6018
Steam (water vapour)
2
red
RAL 3000
Air
3
grey
RAL 7001
Flammable gases
4
yellow or
RAL 1021
yellow with additional red
RAL 3000
yellow with additional black
RAL 1021
or black
RAL 9005
6
orange
RAL 2003
Lyes
7
violet
RAL 4001
Flammable liquids
8
brown or
RAL 8001
brown with additional red
RAL 3000
Non-flammable gases
Acids
Non-flammable liquids
5
9
brown with additional black or black
RAL colour register
RAL 8001
RAL 9005
Oxygen
0
blue
RAL 5015
D.8 Pipework
Note
Determination and
assignment of
categories depends
on the type of fluid
employed (group 1
and/or group 2); see
following diagrams
taken from the Pressure
Equipment Directive
97/23/EC.
D.8.2
Specifications - materials,
welding work
Within the scope of this manual, the intention
is to provide information for selected main
pipes (see chapter C.9) for planning purposes.
In principle, the regulations TRD 100 materials, AD 2000 - datasheets (W4 - pipes
made of non-alloy and alloy steels, W9 - nuts
and bolts made of ferritic steels, W9 - steel
flanges) and material - DIN EN 13480 and
TRD 201 - welding steel components must be
observed.
According to the Pressure Equipment Directive
97/23/EC, corresponding verification of
confirmation of the materials used must be
kept in the project.
For category I parts subjected to pressure (see
chapter D.8.1.3), the provision of a company
certificate according to DIN EN 10204 type
2.2 (confirmation of certification by the
manufacturer) is required. For parts subjected
to pressure in categories II and III, an
acceptance test certificate is required in line
with type 3.1 and/or type 3.2, depending on
the selected and/or required product testing.
188/189
Assignment for media in fluid group 1
(natural gas - E)
Pipe according to Pressure Equipment Directive 97/23/EC
DN = 25
PS
(bar)
DN = 100
II
1000
Article 3, Paragraph 3
100
PS
·D
N
=1
00
·D
N
0
=
35
0
I
DN = 100
10
PS
III
1
0.5
0
DN = 350
Fig. D.8.2–1
Pipes according to Article 3,
number 1.3, letter a), first dash
PS = 0.5
..."The exception here are pipes
intended for use with unstable
1
0.1
10
25
100
350
1000
10,000
DN
gases that fall into categories I and II
according to diagram 6, but need to
be classified as category III."...
Assignment for media in fluid group 2
(steam, condensate, water, fuel oil etc.)
1000
I
100
II
III
0
00
=5
N 3500
·D
=
PS N
·D
00
10
=
PS
PS
N
·D
10
DN = 250
DN = 32
PS
(bar)
DN = 100
Pipe according to Pressure Equipment Directive 97/23/EC
Article 3, Paragraph 3
Fig. D.8.2–2
1
PS = 0.5
0.5
Pipes according to Article 3,
number 1.3, letter a), second dash
0.1
1
10
32
100
1000
250
10,000
DN
..."The exception here are pipes that
contain fluids at temperatures greater
than 350 °C and fall into category II
according to diagram 7, but need to
be classified as category III."...
D.8 Pipework
With reference to the aforementioned standards,
the following are recommended for use:
D.8.2.1
Materials for the pipework
identified in chapter D.8.5
Fig. D.8.2.1–1
Pipes
Ferritic steels:
Material
Material no.
Temperature (°C)
P235TR1
1.02551
≤ 50
P235TR2
P265TR2
Standards
DIN EN 10216-1
DIN EN 10217-1
1.02591
≤ 50
or DIN EN 10224
P235GH
1.03454
≤ 450
DIN EN 10217-23,7
P265GH
1.04255
≤ 450
DIN EN 10217-23,7
16Mo3
1.5415
≤ 500
DIN EN 10217-23,7
13CrMo4/5
1.7335
≤ 500
DIN EN 10217-23,7
10CrMo9/10
1.7380
≤ 500
DIN EN 10217-23,7
14MoV6/3
1.7715
≤ 550
DIN EN 10217-23,7
X10CrMoVNb9/1
1.4903
≤ 600
DIN EN 10217-23,7
P265TR1
DIN EN 10216-2
DIN EN 10216-2
DIN EN 10216-2
DIN EN 10216-2
DIN EN 10216-2
DIN EN 10216-2
DIN EN 10216-2
Austenitic steels6:
X6CrNiMoTI17-12-2
1.45712
≤ 550
Notes
X6CrNiTi18-10
Note 1
Where welded
tubes according to
DIN EN 10217 are used,
a welding factor to be
observed of 0.85 is
recommended for the
strength calculation.
Note 2
The following
documents must also be
observed in the project,
as mentioned previously
(DIN EN 10204),
for the preparation
of acceptance test
certificates:
„For ferritic steels:
AD 2000 datasheet
W4 and TRD 102,
plus
„For austenitic steels:
AD 2000 datasheet
W2 and TRD 102
DIN EN 10217-7
DIN EN 10216-5
1.45412
≤ 550
DIN EN 10217-7
DIN EN 10216-5
Notes
1 Tubes for pressure purposes (seamless
and/or welded) or steel tubes and fittings
for preferred use in the pipework (DHW
system) described in chapter D.8.5.4-C)
and galvanised
2 Stainless steel tube (previous designation
"V4-A") for preferred use in the pipework
(softened water pipework) described
in chapter D.8.5.4-E), seamless and/or
welded
3 For flue systems, here with preferred use
according to DIN EN 10217-2 (as welded
steel tubes)
4
5
6
7
Preferred use also for fuel oil (HEL)
systems (previous designation St 37)
Preferred use also for natural gas (E)
systems (previous designation St 35.0)
Austenitic tubes are employed according
to DIN EN 10216-5 (seamless tubes) and/
or according to DIN EN 10217-7 (welded
tubes)
For "hot-running" pipework (> 100 °C)
preference should be given to the
selection of steel tubes according to
DIN EN 10216-2
190/191
D.8.2.2
Sheet metal materials
Only insofar as is applicable for ferritic
materials according to DIN EN 10028-2,
for example:
Fig. D.8.2.2–1
Materials
D.8.2.3
Flange materials
With reference to and observance of DIN EN
1092-1 on the project side - flanges and their
joints (steel flanges) - as well as DIN EN 102222 - steel forgings for pressure purposes - and
DIN EN 10025 - technical delivery conditions the following recommendations are made:
Material
Material no.
Temperature (°C)
S235JR
1.0037
≤ 100
S235JRG2
1.0038
≤ 300
P235GH
1.0345
≤ 400
Temperature range (°C)
PN16
PN25 to PN40
≥ PN63
≤ 450
≤ 120
S235JRG2 (1.0038)
S235JRG2 (1.0038)
P250GH (1.0460)
P250GH (1.0460)
P250GH (1.0460)
16Mo3 (1.5415)
P250GH (1.0460)
P250GH (1.0460)
P265GH
1.0425
16Mo3
1.5415
≤ 500
13CrMo4/5
1.7335
≤ 530
Fig. D.8.2.3–1
Materials
> 120 to ≤ 400
> 400 to ≤ 500
With acceptance test certificate according to
DIN EN 10024 and AD 2000 datasheet W1,
as well as TRD 101, with information on any
necessary austenitic materials according to DIN
EN 10028-7, such as where a requirement exists
for condensing technologies, and acceptance
test certificate according to DIN EN 10204 and
AD 2000 datasheet W2, as well as TRD 101.
Fig. D.8.2.2–2
Materials
Material
Temperature (°C) Temperature (°C)
X6CrNiMoTI 17-12-2
1.4571
≤ 550
X6CrNiTI18-10
1.4541
≤ 550
P250GH (1.0460)
16Mo3 (1.5415)
16Mo3 (1.5415)
16Mo3 (1.5415)
13CrMo4-5 (1.7335)
13CrMo4-5 (1.7335)
10CrMo9-10 (1.7380)
> 500 to ≤ 550
Notes
„Acceptance test certificates according to
DIN EN 10204, specifically with additional
reference to AD 2000 datasheet W9 and
TRD 100
„As standard, flange types 11 (welding neck
flanges) and 05 (blank flanges) should be
selected
„According to the standard, Form B2 is
recommended for the design of sealing
strips of steam and hot water pipework
and Form B1 for cold water pipework
(≤ 50 °C)
„Welding ends of welding neck flanges
must comply with the subsequent
pipe diameters, taking into account a
permissible edge offset (± 8 % to ± 10 %
of the wall thickness (T) to be joined
according to DIN EN 10216-2/10217 -2,
but with ≤ 2 mm recommended); see
Fig. D.8.2.3-2 and Fig. D.8.2.3-3
DIN EN ISO 5817 - quality categories for
imperfections - must also be observed here.
Note
Respectively observing a permissible operating
pressure due to "decay" of the temperaturedependent material yield point.
10CrMo9-10 (1.7380)
D.8 Pipework
Fig. D.8.2.3–2
Pipe/pipe connection
Key
Di
DNP
60°
X
1
s‘P/sP
sPF
Δx
Swg
˞
2
°a
15
tX
≥
3
Fig. D.8.2.3–3
Pipe/flange connection
60°
0-3
Pipe/flange internal diameter
Pipe straight-through nominal
diameter (external diameter)
Pipe wall thickness
Flange wall thickness
Edge offset (max. ≤ 2 mm)
Weld gap
15° adjustment to Di at Δx > 2 mm
°
15
192/193
D.8.2.4
Nuts and bolts
With reference to and observance of
DIN EN 20898 on the project side unalloyed fasteners - and DIN EN 10268
- alloyed fasteners - and DIN EN 1515 selection of nuts and bolts, the following
recommendations are made:
Fig. D.8.2.4–1
Nuts and bolts
Temperature range (°C)
Components
PN16
PN25 to PN40
≥ PN63 to ≤ 100
≤ 100
Bolt
5.6
--
--
Nut
5
> 100 to ≤ 300
> 300 to ≤ 350
Bolt
5.6
5.6
25CrMo4 (1.7218)
Nut
5
5
C35E (1.1181)
Bolt
--
Nut
> 350 to ≤ 400
Bolt
--
Nut
> 400 to ≤ 450
Bolt
--
Nut
> 450 to ≤ 540
Bolt
--
Nut
25CrMo4 (1.7218)
25CrMo4 (1.7218)
C35E (1.1181)
C35E (1.1181)
25CrMo4 (1.7218)
21CrMoV5-7 (1.7709)
C35E (1.1181)
25CrMo4 (1.7218)
21CrMoV5-7 (1.7709)
21CrMoV5-7 (1.7709)
25CrMo4 (1.7218)
25CrMo4 (1.7218)
21CrMoV5-7 (1.7709)
21CrMoV5-7 (1.7709)
21CrMoV5-7 (1.7709)
21CrMoV5-7 (1.7709)
--
Austenite
Bolta)
A4-70 (A4-50)
A4-70 (A4-50)
≤ 400
Nuta)
A4-70 (A4-50)
A4-70 (A4-50)
Notes
„Acceptance test certificate according
to DIN EN 10204 type 2.2 for fasteners
according to DIN EN 20898 (bolts 5.6 /
nuts 5), specifically with additional
reference to AD 2000 datasheet W7 and
TRD 106, recommending
- Type 3.1 - for nuts according to
DIN EN 10269 and
- Type 3.2 - for bolts according to
DIN EN 10269
„For temperature ranges > 300 °C,
exclusive use of bolted connections with
reduced shank is recommended according
to DIN 2510
a)
Note:
A4-70 to M20 and > M20 (A4-50)
D.8 Pipework
Note
D.8.2.5
Gasket materials must
be completely free of
asbestos.
With reference to and observance of
DIN EN 1514 on the project side - flanges and
their joints - dimensions, type and materials,
the following recommendations are made in
accordance with DIN EN 28091:
Gasket materials
D.8.2.6 Valve body materials
With reference to and observance of
DIN EN 1503 and DIN EN 12516 on the project
side - valve body materials - specifically with
additional reference to TRD 110, Clause 2 and
3, the following recommendations are made:
„As specified in chapter D.8.3.2, but with
additional supplements for ferritic and
austenitic castings, such as:
„Temperature range > 100 °C to ≤ 200 °C,
flat gaskets made from fibrous materials
and/or from graphite with stainless steel
foil insert
„Temperature range > 200 °C, flat gaskets
made from graphite with stainless steel foil
insert and/or chamber profile gaskets with
graphite seat and centring
Fig. D.8.2.6–1
Materials
Material
Material no.
Temperature range (°C)
Nominal pressure range (PN)a)
0.7043
≤ 350
16 to ≤ 40
GP 240 GH
1.0619
> 350 to ≤ 400
16 to > 63
G20Mo5
1.5419
> 400 to ≤ 490
16 to > 63
G17CrMo5-5
1.7357
> 490 to ≤ 570
16 to > 63
GX5CrNiTi19-10
1.4308
> 570 to ≤ 600
16 to > 63
GX5CrNiMo19-11-2
1.4408
> 570 to ≤ 600
16 to > 63
Nodular cast iron
Ferritic casting:
Austenitic casting:
Notes
„In principle, use of cast iron valve
body with material no. 0.6025 is not
recommended
„Exclusive use of corrosion-resistant
materials is recommended for valve
spindles
„Use of nodular cast iron valve bodies with
material no. 07043 according to TRD 108
only up to straight-through nominal
diameters ≤ 150 (DN 175)
„Acceptance test certificates according to
DIN EN 10204, specifically with additional
reference to TRD 110, Clause 6 for:
- Valve group 1 (DN x operating pressure
in bar ≥ 20,000) with test certificate
type 3.2
- Valve group 2 (DN x operating pressure
in bar < 20,000) with test certificate
type 3.1
a)Nominal pressure (PN) selection
as a function of a permissible
operating pressure due to "decay"
of the temperature-dependent
material yield point.
194/195
D.8.2.7 Welding, weld seams etc.
In principle, necessary welding must be
carried out by registered and qualified welding
professionals (welders). These welders
must submit welding certificates relating to
qualification tests according to DIN EN 287-1.
For welding work, the AD 2000 HPO and
TRD 201 approvals are required, along with
the comprehensive qualification certificate
according to DIN 18800 and procedure tests
according to DIN EN ISO 15614.
Welded joints (weld seam preparations) must
be formed according to DIN EN ISO 9692,
in compliance with the following aspects
specified in Appendix [A7]:
„Welding processes
„Additional welding materials
„Welding shielding gases
The following should be available from and/or
provided by the specialist welding company
undertaking the work:
„List of welders and valid welder test
certificates
„Applicable procedure test
(AD2000 HP2/1; DIN EN ISO 15614)
„Welding instructions (WPS)
Non-destructive weld seam tests must
be coordinated with the customer's QA
department, on the basis of and in compliance
with the AD 2000 worksheets and TRD 201, for
circumferential, fillet and connector joints, on
the basis of the aforementioned welding plans.
Certified personnel must be provided for
radiographic and ultrasonic testing, in
accordance with DIN EN 473.
Note
Depending on the material
and the weld seam design,
testing scopes of between
10 %, 25 % and 100 %
may be necessary, with a
recommendation (unless
otherwise specified) for
category II and category III
pressure-bearing pipework
components according to
the Pressure Equipment
Directive of at least 25 %
and 100 % for austenitic
materials.
D.8 Pipework
D.8.3
Pipework calculations and sizing
In the following, suggestions are provided for
necessary calculations. However, any detailed
discourse on physical processes is omitted.
In individual cases, precise calculations must
be carried out again by the implementers
(engineers) with the help of specific calculation
programs.
During the layout and sizing process, the
following standards and regulations must be
observed by engineers:
„AD 2000 - worksheets (focussing on W4
- pipes, W7 - nuts and bolts, and W9 flanges, along with HP100R - pipework and
HP512R - testing of pipework)
„TRDs (focussing on the TRDs for materials,
fabrication, calculation and testing)
„In addition to DIN EN 13480, Part 1 to Part
7 (focussing on Part 2 - materials, Part 3 design and calculation, Part 4 - fabrication
and installation, and Part 5 - inspection and
testing)
D.8.3.1
Calculation of the internal
pipe diameter
For calculation purposes, a flow velocity
used in common-practice and determined as
cost-effectively based on experience forms
the basis for the "initial" approach and the
arising pressure and/or temperature losses are
recalculated accordingly.
At the same time, the losses must comply
with permissible limits (specification by the
system operator/customer).
The values listed in the following table are
recommended as standard values for the flow
velocities to be selected.
196/197
Fig. D.8.3.1–1
Standard values for flow velocity (w):
Type of pipe
Pressure range P (bar)*
Flow velocity w (m/s)
Steam pipes:
Wet steam
≤ 10
10 - 20
Saturated steam
≤1
10 - 15
> 1 to ≤ 5
15 - 25
> 5 to ≤ 10
25 - 35
> 10 to ≤ 40
35 - 40
> 40 to ≤ 100
40 to ≤ 60
Superheated steam: as for saturated steam, but with selection of the respective "higher" velocity
Safety valve discharge pipes and start-up pipe
Around atmospheric
(also mixing cooler air vent pipe)a)
pressure
≤ 70
Exhaust vapour and waste steam pipes, expansion steam
Around atmospheric
in condensate pipes (open system)
pressure
Long-distance steam pipes
< 40
≤ 20
Suction line
≥ 0.5 to ≤ 1
10 - 25
Water pipes:
Condensate pipes
Feedwater pipes
Pressure line
≥ 1 to ≤ 3
Suction line
≥ 0.5 to ≤ 1
Pressure line
Boiler lye and blow-down pipe
≥ 2 to ≤ 3.5
≥ 1 to ≤ 2
(without expansion steam)
Boiler lye and blow-down pipe
≤1
10 - 15
(with expansion steam)
> 1 to ≤ 5
15 - 20
Suction line
≥ 0.5 to ≤ 1.5
Pressure line
≥ 1.0 to ≤ 3.5
Drinking water and DHW pipes
Cooling water
≥ 1 to ≤ 2
Other pipes and ducts:
Compressed air lines
Natural gas pipes
Fuel oil pipes
≥ 10 to ≤ 20
up to ≤ 0,05
≥ 3 to ≤ 8
> 0.05 to ≤ 1
≥ 5 to ≤ 10
> 1 to ≤ 6
> 10 to ≤ 25
Suction line
≥ 0.2 to ≤ 1
Pressure line
≥ 0.5 to ≤ 1.5
Combustion air ducts
Suction line
≥ 8 to ≤ 20
Pressure line
≥ 15 to ≤ 30
Flue ducts
up to chimney connection
≥ 8 to ≤ 15
Note
With reference to none but "short" pipe lengths
to be expected in the steam boiler room, flow
velocities could be selected here close to the
specified upper limits.
a) For the mixing cooler ventilation
duct, flow velocities can be
selected according to specified
details due to the short-term
nature of loads from boiler
blow-down.
* The pressures referred to in this
manual are exclusively positive
pressures, unless explicitly stated
otherwise.
D.8 Pipework
D.8.3.2
Flow rate in pipes, calculation of
the internal pipe diameter
In the following, equations are presented for
calculating volumetric flow rate, mass flow
rate, flow velocity and internal pipe diameter.
Notes regarding case 1
Calculation for the operational state based on
the equation for conversion of an air or gas
flow from the standard state to the operational
state with:
9
ɘ Pu 9
ɘ 1૷[
From the general equation for volumetric
flow rate V̇ = w x A, with A being the flow
cross-section (in m²), the following can be
determined:
S
Volumetric flow rate
૷
GL[˭
ˮ
GL[˭
[ˮ[Z
Flow velocity
9ɘ
Z
GL [˭
ˮ[9ɘ >[email protected]
૷
GL[˭[ˮ
Internal pipe diameter
9ɘ
GL [
[
˭[Z
෭
Note
>[email protected]
૷
˭[ˮ[Z
>[email protected]
with calculation variables for:
ˮ, Y (see [Tb. 2]) for
steam and water)
and properties for air,
flue gas, natural gas,
fuel oil according to
overview (approximately)
Fig. D.8.3.2-1.
Fig. D.8.3.2–1
෭
w Flow velocity (see standard values from
table in chapter D.8.3.1, Fig. D.8.3.1-1)
ˮ Density of the medium (in kg/m³) (ˮ = 1/Y)
Y Specific volume of the medium in
[m3/kg] = where p=1/Y
Density (kg/m³) overview for various media
Medium
ˮ [T = (15 °C) 20 °C]
ˮ [T = 50 °C]
ˮ [T = 100 °C]
ˮ [T = 0 °C (standard state)]
Air1
1.207
1.095
0.948
1.293
1.251
1.135
0.983
1.34
0.732
--
--
0.784
Flue gas1
Natural
gas1
Fuel oil1
(E)
(LL)
0.774
(EL)
(840)
815
--
--
0.829
(S)
(960)
940
910
--
>[email protected]
[S
7
>[email protected]
although with each neglecting the "operating
pressures" (p in bar)
[Z >[email protected]
Mass flow rate
૷
7
and/or the density directly with:
ˮNJPu ˮNJ1Pu[
9
ɘ [
198/199
Sample calculation 1 - steam pipe
Sample calculation 2 - natural gas pipework
„Saturated steam/fresh steam output
Saturated steam parameters as in 1st sample calculation, plus:
૷ FS = 12,000 kg/h
„Saturated steam enthalpy (from [Tb. 2])
„Saturated steam/fresh steam pressure
„Feedwater enthalpy (from [Tb. 2])
pB = 13 bar
(assuming feedwater temperatures Tfw ≈ 104 °C)
„Specific steam volume (from [Tb. 2])
with ECO type 200 (from Vitomax 200-HS datasheet)
„Selected flow velocity from
[
෭
෭
≈ 94.6 %
„Lower net calorific value Hi-natural gas
w ≈ 35 m/s
= 10.35 kWh/Nm³
„Fuel demand સ F (see chapter D.4.3.1) from:
Required internal pipe diameter
GL [
= 0.1213 kWh/kg
„Steam boiler efficiency Š K(M))
Y''B = 0.1414 m³/kg
Fig. D.8.3.1-1
= 0.7744 kWh/kg
સ)ป
9ɘ
NJK[N:KNJN:KNJ[
ป1PuK
N:K1Puy
˭[Z
NJKyPuNJ
˭[PV
K
[
P
„Natural gas flow pressure (assumption)
≈ 4.0 bar
V
„Conversion of fuel demand (સ F ) into operational state (સ*F ) at 20 °C ambient temperature
„Selected: DN 125 according to DIN EN 10216-2
સ)ป
[
ปPuK
For standard wall
thickness
s=
4.0 mm
External diameter
da = 139.7 mm
Internal diameter
di = 131.7 mm
„Selected flow velocity from Fig. D.8.3.1-1
≈ 17 m/s
„Required internal pipe diameter
GL [
[NJK[PuNJ[K
ZDYDLO
Ptt[˭[V
>[email protected]
෭
PuK
P
˭[VK[PV
„Selected: DN 65 according to DIN EN 10216-2
thus yielding a maximum flow velocity (wavail) of
34,62 m/s < w selected
For standard wall thickness
s = 2.9 mm
External diameter
da= 76.1 mm
Internal diameter
di = 70.3 mm
4 x 173.59 m³ x h
wavail = 0.07032 m2 x 3600 s/h x = 12.43 m/s
˭
thus available flow velocity wavail < wselected
D.8 Pipework
D.8.3.3
v-
Pressure losses
The pressure loss in a pipeline results from
the sum of individual losses from all pipeline
components, such as pipes, fittings, valves,
changes in cross-section and other inbuilt
parts. In the case of gaseous media, the
change in volume of the flowing medium due
to expansion must be considered. However,
this parameter is omitted in the following
calculations due to its negligible impact on
the result. The pressure loss calculations for
liquids and gases are therefore the same in
this context.
Š-
the kinematic viscosity of the medium (in
[m²/s]) and/or
the dynamic viscosity from
Š Y[ˮLQ
>
NJ
P[V
3D[V
1V
Pt
@
(see following tabular overview for several
selected media)
and
di - the internal pipe diameter (in [m]) and/or
dgl - the equivalent diameter in the case of
an angular cross-section (in [m]) (see
description in D.3.4-B)
and therefore the drag coefficient - ˨R from the
If the pipeline has different diameters (changes
in cross-section), the associated pressure
losses must be determined accordingly in
sections.
equations for
According to [L8] and [L9], the "total pressure
losses" Δˮtot to be expected are calculated
from:
˨Rb) = 64 / Re [-]
ෙSWRW
ˮ
[Zt
˨5
/
GL
ːˣ (
[
>[email protected]
D.8.3.2) in (m/s)
Drag coefficient (coefficient of friction) of
the pipeline, dimensionless, determined
as a function of available flow types
(laminar and/or turbulent). The flow type
is based on the dimensionless index
(Re), the so-called Reynolds' number,
calculated from:
5H
and
a)
Specific information from the valve
manufacturer, if applicable, should
also be observed here.
b)
c)
˨R - depends only on the Re number.
˨R - depends only on the relative
roughness - kR/di.
Z[GLGJO
ˮ[Z[GL
˪
Š
turbulent flow - assuming a "smooth pipe" for
ranges Re ≤ 105
˨5E
with the individual calculation variables for:
ː ˣE - Sum of all individual resistancesa)
dimensionless (see [Tb. 4]) and/or [L5/L9]
LPipeline length in [m]
di - Internal pipe diameter in [m]
ˮ= 1/v (density of medium, see chapter
D.8.3.2) in [kg/m³]
w - Selected and/or available flow velocity
[wavail] (see chapter D.8.3.1 and/or
˨R -
laminar flow
Re ≤ 2300
>@
෭5
>@
H
turbulent flow - assuming a "smooth pipe" for
ranges Re ≥ 105 to ≤ 108
˨5E []
5H
and
for the "completely rough pipe"
˨5F OJ[
N5
GL
>@
200/201
with wall roughness values (kR) to be assumed
here according to table:
Fig. D.8.3.3–1 Wall roughness
Material
Steel pipes
Steel pipes
Cast iron
Cast iron pipes
Concrete
Concrete
Sheet metal
condition
(new)
(rusty)
pipes (new)
(rusty)
(smooth)
(rough)
ducts (seamed) pipes
PVC/PE
kR (mm)
0.04 - 0.1
0.4 - 0.6
0.5 - 1.0
1.0 - 1.5
0.3 - 0.8
1.0 - 3.0
0.15
0.007
See also specifications in chapter G
[Tb. 3]
Notes
1. Values for ˨R can be determined reliably as
a function of the Re number and the quotient
di/kR from the enclosed diagram in chapter G
[Tb.3.1].
2. An estimate of ˨R ≈ 0.02 to 0.04 can be
selected with sufficient accuracy for rough
calculations.
Extra assistance for calculating pressure
losses in a straight pipeline for the media
steam and water can also be provided with
sufficient accuracy by the enclosed diagrams
in [Tb. 4; 4.1.8].
d)
In the diagram in chapter G, Tb.4.0,
˨R values of 0.0206 (according
to Eberle) have been used and
therefore contain corresponding
reserves compared with the
depicted calculations.
D.8 Pipework
Overview of kinematic viscosity (Y) for
selected media [L9] [L11]
Fig. D.8.3.3–2
Saturated steam
ts (°C)
100
120
150
180
200
230
250
280
300
Y (m²/s) y 10-6
20.013
11.463
5.469
2.929
2.033
1.241
0.913
0.6
0.461
Note for superheated steam: see diagram according
to Timroth; the values for saturated steam can also
be selected here with sufficient accuracy.
Fig. D.8.3.3–3
Sample calculation 1 - Steam line pressure loss (ΔpR)
Values corresponding to chapter D.8.3.2 (for 1st
sample calculation) plus
„Steam density
Superheated steam – diagram according to Timroth
1
ˮ'' =
Y
$EVROXWH
SUHVVXUHLQEDU
1 kg
=
Internal pipe diameter
di = 0.1317 m
300
250
Available flow velocity
'\QDPLFYLVFRVLW\ǹLQ3DyV
200
= 7.072 kg/m3
0.1414 m³
wavail = 34.62 m/s
150
Pipe length (assumed)
100
L = 20 m
80
60
Saturated steam temperature (Ts from Tb. 2) ≈ 195 °C
40
20
Viscosity at
Ts (approximated)
≈ 2.257 · 10-6 m²/s
6WHDPWHPSHUDWXUH7LQr&
Reynolds' number Re
R e
Fig. D.8.3.3–4
34.62 m/s x 0.1317 m
2.257 x 10 -6 m2 /s
Fuel oil – air – water – flue gas
= 2.02 x 10 6 > 10 5 [-]
Drag coefficient for "smooth pipe"
T (°C)
20
50
100
Oil
Y (m²/s) x 10-6
Y (m²/s) x 10-6
Y (m²/s) x 10-6
Fuel oil (S)
1520
300
30
Fuel oil (EL)
5.0
2.6
/
Air a)
at 1.013 bar absolute
˨R =
0.0032 +
= 0.0032 +
15.11
17.94
23.06
at 5 bar absolute
3.105
3.657
4.712
Water
1.004
0.553
0.295
0.221
(2.02 · 10 6) 0.237
0.221
31.215
= 0.0103
[-]
yielding
ΔpR =
7.072 kg/m3
2
(
x (34.62 m/s)2 x 0.0103 x
20 m
0.1317 m
)
x
= 0.0663 bar or 0.003315 bar/m
Normal practice and acceptable pressure losses of
ΔpR ≈ 0.003 bar/m of pipe can be used.
a) Also applies approximately to
natural gas.
b) (Source: Weishaupt) on
combustion of fuel oil with an
excess of air (˨L) between 1.1
to 1.2.
1
10 5
202/203
Ex. 2 - Pressure loss in the feedwater suction line (ΔpR/S)
Cont. - Pressure loss in the feedwater suction line (ΔpR/S)
Feedwater suction line:
Standard practice and acceptable pressure losses of
Amount of feedwater
૷fw = 12,000 kg/h
Feedwater temperature
Tfw = 104 °C
Feedwater density (according to [Tb. 2])
ˮfw = 955 kg/m³
Selected flow velocity (see standard values in table
in chapter D.8.3.1)
recommended.
Wit additional assumptions for:
Ltot = 5 m
Individual filter resistance (1x) (clean)
w = 1.0 m/s
Pipe length (assumed)
L=1m
ˣ F ≈ 3.0
Individual valve resistance (2x)
Required internal pipe diameter
di erf = 2 x √
In light of the
information specified
in chapter D.6.1,
sizing of the suction
line for values of
Δptot/s ≤ 500 mmWC is
recommended.
ΔpR/S ≈ 10 to 20 mmWC per metre of pipe can be
Suction line length - total
ˣV ≈ 2 x 3.7 = 7.4
Individual 90° bend resistance (3x)
12,000 kg/h x s xh
˭ x 955 kg/m 3 x 1 m x 3600 s
= 0.0668 m
selected: DN 65 according to DIN EN 10216-2
For standard wall thickness s = 2.9 mm
ˣ B ≈ 3 x 0.2 = 0.6
Sum of individual resistances:
ːˣE = 3.0 + 7.4 + 0.6 = 11
Total suction line pressure loss
External diameter
da = 76.1 mm
Internal diameter
di = 70.3 mm
ෙSWRWV
NJP
EDUP[P[
resulting in an available flow velocity of
wavail =
4 x 12,000 kg/h x h
0.07032 m2 x 3.14 x 955 kg/m3 x 3600 s
= 0.89 m/s
[PV[
EDU
DQG
[EDU[PP:&
Viscosity at Tfw ≈ 0.295 x 10-6 m²/s
ෙSWRWV
Reynolds' number
0.89 m/s x 0.0703 m
Re =
= 2.21 x 10 5 > 10 5 [-]
0.295 m2 /s x 10 -6
Drag coefficient for "smooth pipe"
0.221
˨ R = 0.0032 +
= 0.0032 +
ΔpR/S =
922
2
(2.12 x 10 5) 0,237
0.221
18.29
(
= 0.0153 [-]
x 0.89 2 x 0.0153 x
1
0.0703
)
x
1
10 5
= 0.000823 bar/m
and
ΔpR/S =
0.000823 x bar x mmWC
9.81 x 10 -5 x bar x m
= 8.39 mmWC/m
[[EDU
PP:&
Note
D.8 Pipework
D.8.3.4
Heat and temperature losses
Heat losses can arise due to conduction,
convection and radiation. Two or even all three
types frequently occur together as a thermal
transfer.
Conduction, convection and radiation of heat
are different processes subject to different
physical laws, which need not be described in
any greater detail in the following.
Thermal insulation has the task of
economically minimising these losses to
the greatest extent possible. With reference
to and in compliance with the following
specified standards and directives, losses of
≤ 100 W/m² surface area and maintenance of
average thermal conductivity coefficients (see
Fig. D.8.3.4-1) must be ensured.
Fig. D.8.3.4–1
Coefficients of thermal conductivity
Mean temperature in °C
Thermal conductivity coefficient
50
100
150
200
250
350
0.04
0.045
0.055
0.065
0.075
0.09
(W/mK) for: Mineral fibre shells
Thermal conductivity coefficient
(W/mK) for: Mineral fibre mats
0.035
0.039
0.046
0.055
0.066
0.081
In the case of "normal" air movement (wind
speeds < 5 m/s), maintaining a surface
temperature on the exterior of the sheet metal
jacket no higher than 20 K above ambient
temperature is recommended.
The following fundamental standards should
be observed:
„DIN 4102-T1 - (building material category
A1)
„DIN 4140 - Insulation work on industrial
installations and building equipment;
execution of thermal and cold insulations
„Technical datasheets from the
Arbeitsgemeinschaft Industriebau e. V.
(AGI worksheets)
„VDI Guideline 2055 - Thermal insulation
for heated and refrigerated industrial and
domestic installations
„EnEV - [German] Energy Saving Ordinance
(minimum requirement according to
paragraph 12)
In the enclosed tables (see Appendix [A2]),
typical values are provided with sufficient
accuracy for determining cost-effective thermal
insulation of pipes and contact protection
insulation. Insofar as is dictated by processrelated issues, the insulation thickness should
be determined independently from economic
principles.
Notes regarding
A) Contact protection insulation
Contact protection is recommended
in cases where, at normal operating
temperature, object surface temperatures
> 60 °C can occur "temporarily", e.g.
discharge pipes and objects partially
accessible for inspection of certain
surfaces (platforms, walkways, etc.).
In individual cases, perforated sheet steel
covers (without insulation material) can
be provided instead of thermal insulation,
e.g. drainage systems, ventilation facilities
or as large-area contact protection
on steam boiler components etc., in
accessible areas.
B) Low temperature insulation or insulation for
the prevention of condensation
In this case, the insulation is designed
according to criteria for the prevention of
condensation forming on "cold-running"
pipework systems (e.g. untreated and
softened water pipes). The specific
circumstances must be taken into
consideration here on a system-related
basis. Use can be made with sufficient
accuracy of the typical values in the
following table in accordance with
Appendix [L10]; see Fig. D.8.3.4-3.
C) Protection against moisture
Insulating materials must be protected
with appropriate measures against
moisture, such as ingress of rainwater. The
insulating materials must be stored and laid
in an absolutely dry environment. Reuse of
insulation that has become "damp" is not
recommended.
Additional installation of suitable
monitoring systems is recommended for
pipework in the open air, such as longdistance pipeline systems.
D) Heat loss and temperature drop in "hotrunning" pipes
With reference to the specifications in
[L5] and [L10], the arising losses can be
calculated in simplified terms as follows:
204/205
+HDWORVV
Calculation example
˭[707$[/3
4
ɘ /3 ˨
ᔉ
'D
'L
>:@
˞D['D
Note
With data according to 1st sample calculation -
„Steam output
૷ M = 12,000 kg/h ฬ 3.33 kg/s
„Steam temperature
With calculation variables for:
„Media temperature - TM [°C]
„Ambient temperature - TA [°C]
„Insulating material coefficient of thermal
conductivity - ˨[W/mK] (with reference to TM)
„External/internal diameter of the insulation
Da/Di in [m]
„Heat transfer coefficient at the insulation
surface - ˞a in [W/m²K] with typical values
for - ˞a:
It is assumed that
flanges and valves are
installed throughout
with thermal insulation
and can therefore
be included in
the calculation as
continuous pipes.
Heat losses caused by
pipe brackets should
also be considered,
if applicable, with a
proportionate loss of
15 % (for interiors) to
25 % (for arrangements
in the open air).
Exceptions to this
rule are valves with
electronic sensors or
actuators. Due to their
heat sensitivity, such
valves must not be
enclosed in insulating
material, e.g. steam
output meter.
steam pipework, as in chapter D.8.3.2:
T M = 195 °C
„Ambient temperature
TA (assumed) = 20 °C
„Pipe length
L P (assumed) = 1 m
„Insulation internal diameter
Di = 139.7 mm
(External pipe diameter)
„Insulation external diameter
Da = 279.7 mm
(assumed in accordance with selected
insulation thickness of 70 mm from [A5])
„Insulating material coefficient
˨ ≈ 0.055 W/mk
of thermal conductivity
(assuming mineral fibre mats)
„Heat transfer coefficient
˞a ≈ 3.5 W/m² K
(assumed)
Q̇L/P ≈
Fig. D.8.3.4–2
Heat transfer coefficient
Vertical pipes
Horizontal pipes
2˨
˞ a≈ 5.6 W/m²K
in buildings
˭ x (T M - TA ) x L P
1
ᔉ
˞ a≈ 3.5 to 5.6 W/m²K
Di
+
1
˞a x Da
Z˭[[
:P
in buildings with
Da
[
ᔉ
[
Da ≤ 1000 mm
Pipes in open air
˞ a≈ 20 to 40 W/m²K
up to Da ≤ 700 mm
and with reference to a 1 m² surface:
Q̇L/P ≈ 74.94 W/m x 1/(0.2797 x 3.14 x m/m²)
≈ 85.33 W/m2
Temperature drop (ΔTM)
In general the following applies with reference
to the flowing medium (in ૷M):
4
ɘ /3 ૷0[FS0[ෙ70:
or
ෙ70 4
ɘ /3૷0[FS0
With calculation variables for:
„Heat loss Q̇L/P - in [W and/or W/m]
„Medium mass flow rate - ૷ M in [kg/s]
„Specific thermal capacity - cpM of the
flowing medium at constant pressure in
[Ws/kg K] where:
cpWater ≈ 4200 Ws/kgK and
cpSteam - [Tb. 2] diagram for saturated steam
and
[Tb. 2.3] diagram for superheated
steam
and with specific thermal capacity
(cpM - for steam from [Tb2]) ≈ 2939 Ws/kgK
results in
ΔT M = Q̇L/P/ (૷ M x cpM)
= 74.94/(3.33 x 2939) W/m kg K s / (Ws kg m)
= 0.00766 K/m
Fig. D.8.3.4–3
Insulation thickness as a function of relative humidity
Air temperature (°C):
20
25
30
35
80 %
16.5
21.4
26.3
31.0
85 %
17.5
22.4
27.3
32.2
Dew point temperature (°C):
Air at relative humidity:
90 %
18.5
23.5
28.4
33.3
Economical insulation
Inside buildings
40
65
90
110
thickness (in mm):
Outside buildings
10
20
25
30
D.8 Pipework
Notes
Fig. D.8.3.4–4
Diagram for determining heat transfer coefficient ke
„Flanges and pipe
brackets cause
additional heat
losses. Insulated
flanges are included
in calculations as
continuous pipes,
while insulated
flanges with flange
caps must be
considered by adding
1 m to the pipe
length. Pipe brackets
increase heat losses
in the interior by
≈ 15 % and in the
open air by ≈ 25 %
„Detailed calculations
- see VDI Guideline
2055
„Although
documented
sufficiently for
practitioners in
chapter D.8.3.4
Fig. D.8.3.4–5
Source: GESTRA
Diagram for determining diameter factor fd
!
Fig. D.8.3.4–6
Source: GESTRA
Diagram for determining wind factor fW
˨ - Coefficient of thermal conductivity
for selected insulating material (see
also table Fig. 8.3.4-1)
Source: GESTRA
206/207
E) Heat loss and temperature drop in "hotrunning" pipes
With the help of empirical equations and
layout diagrams (source: Gestra), the
following can be determined on the basis
of the cited calculation examples:
„Heat loss (Q̇i) for 1 m pipe length in the
building:
Q̇i = ke x fd x (T M - TA ) in [W/m] and
„Heat loss (Qf) for 1 m pipe length in the
open air:
Q̇f = ke x fd x f w x (T M - TA ) in [W/m]
With calculation variables for:
Media temperature - T M (°C)
Ambient temperature - TA (°C)
and the reading (see Fig. D.8.3.4-4 to
Fig. D.8.3.4-6) for:
Heat transfer coefficient for a - ke (W/m² K)
for an even wall
Diameter correction factor - fd (m²/m)
Wind factor - f w
Sample calculation 1
„Insulating layer thickness s = 40 mm
„Coefficient of thermal conductivity ˨ = 0.058 W/m K
„External pipe diameter da = 48.3 mm
„Temperature of the medium T M = 160 °C
„Ambient temperature TA = 20 °C
„Reading:
ke = 1.25 W/m² K
fd = 0.27 m²/m
fw = 1.068
Result for the interior:
Q̇i = ke x fd x (T M - TA )
= 1.25 W/m² K x 0.27 m²/m x (160 - 20) °C
= 47.3 W/m
Result for open air:
Q̇f = ke x fd x f w x (T M - TA )
= 1.25 W/m² K x 0.27 m²/m x 1.068 x (160 - 20) °C
= 50.5 W/m
D.8 Pipework
Temperature drop (ΔTM) in "hot-running" pipes
(water-bearing):
The following rule of thumb applies:
ΔTM = Q̇i(f) / (cpw x ૷w) [K/m]
With calculation variables for:
„Heat loss - Q̇i and/or Q̇f - [W/m] see
calculation example 1 under E)
„Specific thermal capacity - [Ws/kg K]
cpWater ≈ 4200 Ws/kg K and
„Water mass flow rate ૷ W [kg/s]
Temperature drop (ΔTS) in "hot-running" pipes
(steam-bearing):
As for water-bearing, but with the assistance
of and readings from Fig. D.8.3.4-5
Sample calculation 2
Steam temperature = 220 °C
Steam pressure = 10 bar (abs)
Steam mass flow rate = 30 x 10 3 kg/h
Heat loss Q̇f
(see sample calculation 1) = 50.5 W/m
Result from Fig. D.8.3.4-5
ΔT S ≈ 0.0028 K/m
208/209
Diagram for determining temperature drop as a function of steam temperature, steam pressure and steam mass flow rate
!
Source: GESTRA
Fig. D.8.3.4–5
D.8 Pipework
D.8.4
Strength, expansion, support spans,
clearances, routing / mountings
The major applicable calculation and sizing
principles to be taken into consideration
during engineering were described by way of
introduction in chapter D.8.3.
The materials flowing through a pipeline
subject the pipe walls to loads due to
positive or negative pressure. In addition
to these loads, thermal stresses due to the
arising temperature gradient in the pipe
wall must also be considered in the case of
hot-running pipes.
This temperature gradient is of particular
significance when starting up and
shutting down the system, especially with
"thick-walled" pipes.
Further loads arise due to prevented changes
in length of the pipework system between
the fixed points and restrictions resulting from
deflection between the individual supports.
A) Strength
For the purpose of ensuring an "adequate"
pipe wall thickness, the pipes must be sized
accordingly, with reference to cited standards
and regulations, for the arising operating
conditions (static loads up to 120 °C and/or
> 120 °C as well as varying loads).
In the final analysis, the selected pipe wall
thickness to be implemented (sselected) must
satisfy the conditions: sselected ≥ SV + C1 + C2.
Where:
„SV - The calculated required wall thickness
„C1 - Supplement taking account of the
permissible shortfall in wall thickness
„C2 - Supplement for corrosion and wear
210/211
In order to avoid excessively high forces at
the fixed points, provision must be made for
appropriately designed expansion joints. Prestressing of the pipe can compensate for the
stresses caused by thermal expansion during
operation. Where this is not possible naturally,
appropriate expansion joints (compensators)
must be included in the design in the form of
pipe-leg and horseshoe-bend expansion joints,
lyra expansion loops, or axial, restrained, and
angular expansion joints.
Precise calculation of the reaction forces
occurring at the respective fixed points is
difficult and should be carried out with the help
of conventional computer programs, such as
"ROHR-2".
The determination of permissible reaction
forces (lateral forces) and torques is carried out
on the basis of and in compliance with relevant
manufacturer's specifications.
This applies primarily to:
„Valves and connectors on steam boilers
Note: In this context, Viessmann requires
"stress-free" connection
„Valves and connectors on pumps in the
system
„Valves and connectors on the thermal
devices in the system
With the commencement of engineering
the installation of individual components,
the possibility must be investigated at this
early stage of a "structurally soft" mounting
of the pipework system, by means of routing
options and incorporating appropriate "natural"
pipe deviations for the purpose of expansion
compensation.
One good option is the inclusion of so-called
pipe-leg expansion joints (see diagram for
pipes according to DIN EN 10220). Pipe-leg
and U-bend expansion joints are manufactured
from the same material as the pipe in
question. The pipe legs are pre-stressed
during installation with 50 % of the expected
expansion (ΔL).
Fig. D.8.4–1
Expansion compensator diagram
m
Required pipe leg length in m
B) Expansion
Pipes bearing "hot-running" flow media
undergo a change in length (ΔL) during
operation.
Calculated from ΔL = Lo x ˞ x ΔT in [mm],
where
„Lo - Rectilinear distance between two
fixed points in the pipework system
in [m]
„˞ - Expansion coefficient for ferrous
materials ˞ ≈ 12 x 10 -6 [m/mK]
„ΔT - Temperature increase [K],
for example:
ΔT = (120 °C - 20 °C) = 100 K
Lo = 1 m
ΔL = 1 m x 12 x 10 -6 m/mK x 100 K
= 1.2 x 10 -3 m = 1.2 mm/m
nf
0
=4
0m
tio
a
ns
pe
m
o
nc
sio
an
p
Ex
Fixed point
.
I = Expansion in mm
Da = Ext. pipe dia. in mm
l = pipe leg length in m
Nominal diameter
D.8 Pipework
C) Support span
The effects of inertia forces (line stress due
to insulation, pipe filling and pipe weight) on
the permissible deflection and/or permissible
stress are limited by the definition of suitable
support spans.
Proof of permissibility is considered to have
been furnished if the support spans according
to AD 2000 - datasheet HP100R - are observed
for the steel pipeline.
Fig. D.8.4–2
Extract: permissible support span in (m) for steel pipes
Nominal diameter
Pipe wall thickness
(s in mm)
DN 25
DN 40
2.0
DN 50
DN 80
DN 100
DN 150
4.0
2.0
4.0
2.0
4.5
2.3
5.6
2.6
6.3
2.6
7.1
2.9
2.9
3.5
3.5
4.5
4.4
5.5
5.4
6.3
6.2
7.6
7.5
2.7
2.8
3.1
3.3
3.9
4.1
4.6
5.0
5.1
5.6
5.8
6.6
2.0
2.2
2.5
2.3
3.2
3.6
4.0
4.5
4.6
5.2
5.4
6.3
1.8
2.0
2.8
3.2
2.9
3.3
3.7
4.3
4.4
5.0
5.2
6.1
Permissible support span, L1 in m
Empty pipe
(uninsulated)
Water-filled pipe
(uninsulated)
Water-filled pipe (insulated)
Dda) 40
Water-filled pipe (insulated)
Dda) 80
Fig. D.8.4–3
Extract: permissible support span in (m) for steel pipes
Nominal diameter
Pipe wall thickness
(s in mm)
DN 200
DN 250
DN 300
DN 350
DN 400
DN 500
2.9
7.1
2.9
7.1
2.9
8.0
3.2
8.8
3.2
10.0
4.0
11.0
8.7
8.7
9.7
9.7
10.6
10.6
11.1
11.1
11.9
11.8
13.3
13.2
6.5
7.4
6.9
8.0
7.3
8.7
7.7
9.1
8.0
9.7
8.9
10.7
6.1
7.1
6.6
7.7
7.0
8.4
7.4
8.8
7.7
9.5
8.7
10.5
5.9
6.9
6.5
7.6
6.9
8.3
7.3
8.7
7.6
9.4
8.6
10.4
Permissible support span, L1 in m
Empty pipe
(uninsulated)
Water-filled pipe
(uninsulated)
Water-filled pipe (insulated)
Dda) 40
Water-filled pipe (insulated)
Dda) 80
a)
Dd = Insulation thickness in [mm].
212/213
Based on empirical values and applicable in
practice, the following information summarised
in tables a) to e) is of use in initial design
considerations:
Fig. D.8.4–4
a) Support span (b) in (m) for PVC pipes, hard PVC up to 20 °C (source: Gestra)
Nominal diameter
DN 25
DN 32
DN 40
DN 50
DN 65
DN 80
DN 100
DN 125
DN 200
Support span (m)
1.0
1.1
1.25
1.4
1.5
1.65
1.85
2.15
2.6
For steel pipes (source: Mannesmann) with
a permissible deflection (fperm = 5 mm) and
permissible stress (˰perm = 40 N/mm²)
Fig. D.8.4–5
d mm
b) Support spans in (m) - seamless steel pipe (d x s) - with water and insulation thickness (Dd)
s mm
qM kg/m
Dd =
50 mm
100 mm
150 mm
200 mm
250 mm
300 mm
0 mm
60.3
2.9
6.4
4.1
3.4
3.0
2.8
2.4
2.1
1.9
63.5
2.9
6.9
4.2
3.5
3.1
2.9
2.5
2.2
1.9
70.0
2.9
8.0
4.3
3.7
3.3
3.1
2.7
2.4
2.1
76.1
3.2
9.6
4.5
3.9
3.6
3.3
3.0
2.7
2.4
88.9
3.2
12.1
4.8
4.2
3.9
3.6
3.4
3.0
2.7
101.6
3.6
15.7
5.1
4.6
4.3
4.0
3.8
3.6
3.2
108.0
3.6
17.2
5.3
4.7
4.4
4.1
3.9
3.7
3.4
114.3
3.6
18.8
5.4
4.8
4.6
4.3
4.0
3.8
3.5
127.0
4.0
23.3
5.7
5.2
4.9
4.6
4.4
4.2
4.0
133.0
4.0
25.0
5.8
5.3
5.0
4.7
4.5
4.3
4.1
139.7
4.0
27.0
5.9
5.4
5.1
4.9
4.6
4.4
4.2
159.0
4.5
34.8
6.3
5.8
5.6
5.3
5.1
4.9
4.7
168.3
4.5
38.1
6.4
6.0
5.7
5.5
5.3
5.0
4.9
193.7
5.6
52.1
6.9
6.5
6.3
6.1
5.9
5.7
5.5
219.1
6.3
66.6
7.4
7.0
6.8
6.6
6.4
6.2
6.0
244.5
6.3
79.2
7.7
7.3
7.1
6.9
6.7
6.6
6.4
273.0
6.3
94.7
8.0
7.7
7.5
7.3
7.1
6.9
6.7
323.9
7.1
130.8
8.6
8.3
8.2
8.0
7.8
7.7
7.5
355.6
8.0
159.2
9.1
8.8
8.7
8.5
8.3
8.2
8.0
406.4
8.8
205.0
9.7
9.4
9.3
9.1
9.0
8.8
8.7
457.0
10.0
260.2
10.3
10
9.9
9.8
9.6
9.5
9.3
508.0
11.0
320.3
10.8
10.6
10.5
10.3
10.2
10.1
9.9
610.0
12.5
453.0
11.7
11.5
11.4
11.3
11.2
11.1
11.0
D.8 Pipework
Fig. D.8.4–6
d mm
c) Support spans in (m) - welded steel pipe (d x s) - with water and insulation thickness (Dd)
s mm
qM kg/m
Dd =
50 mm
100 mm
150 mm
200 mm
250 mm
300 mm
0 mm
60.3
2.9
6.4
4.1
3.4
3.0
2.8
2.4
2.1
1.9
63.5
2.9
6.9
4.2
3.5
3.1
2.9
2.5
2.2
1.9
70.0
2.9
8.0
4.3
3.7
3.3
3.1
2.7
2.4
2.1
76.1
2.9
9.1
4.5
3.8
3.5
3.2
2.9
2.6
2.3
88.9
2.9
11.6
4.8
4.1
3.8
3.6
3.3
2.9
2.6
101.6
2.9
14.3
5.0
4.4
4.1
3.8
3.6
3.3
2.9
108.0
2.9
15.7
5.1
4.6
4.3
4.0
3.8
3.4
3.1
114.3
2.9
17.2
5.2
4.7
4.4
4.1
3.9
3.6
3.2
127.0
3.2
21.2
5.5
5.0
4.7
4.4
4.2
4.0
3.6
133.0
3.2
22.8
5.6
5.1
4.8
4.6
4.3
4.1
3.8
139.7
3.2
24.7
5.7
5.2
4.9
4.7
4.4
4.2
3.9
159.0
3.2
30.6
6.0
5.5
5.2
5.0
4.8
4.6
4.3
168.3
3.6
35.0
6.2
5.7
5.5
5.3
5.0
4.8
4.6
193.7
3.6
44.2
6.5
6.1
5.9
5.6
5.4
5.2
5.0
219.1
4.0
56.2
6.9
6.5
6.3
6.1
5.9
5.7
5.5
244.5
4.0
67.7
7.2
6.8
6.6
6.4
6.2
6.0
5.8
273.0
4.0
81.7
7.4
7.1
6.9
6.7
6.5
6.3
6.2
323.9
4.0
109.9
7.9
7.5
7.4
7.2
7.0
6.9
6.7
355.6
4.0
129.6
8.1
7.8
7.6
7.5
7.3
7.2
7.0
406.4
5.0
172.9
8.8
8.5
8.4
8.2
8.1
7.9
7.8
457.0
5.0
212.7
9.2
8.9
8.7
8.6
8.5
8.3
8.2
508.0
5.0
256.8
9.5
9.2
9.1
9.0
8.8
8.7
8.6
559.0
6.0
316.8
10.1
9.8
9.7
9.6
9.5
9.4
9.2
610.0
6.0
370.2
10.4
10.1
10.0
9.9
9.8
9.7
9.6
660.0
6.0
426.6
10.6
10.4
10.3
10.2
10.1
10.0
9.9
711.0
6.0
488.1
10.9
10.6
10.6
10.5
10.3
10.2
10.1
762.0
6.0
553.7
11.1
10.9
10.8
10.7
10.6
10.5
10.4
813.0
6.0
623.3
11.3
11.1
11.0
10.9
10.8
10.7
10.6
864.0
6.0
697.1
11.5
11.3
11.2
11.2
11.1
11.0
10.9
914.0
6.0
773.4
11.7
11.5
11.4
11.4
11.3
11.2
11.1
1016.0
6.0
941.1
12.1
11.9
11.8
11.7
11.7
11.6
11.5
214/215
Fig. D.8.4–7
d mm
d) Support spans in (m) - seamless steel pipe (d x s) - empty pipe and insulation thickness (Dd)
s mm
qM kg/m
Dd =
50 mm
100 mm
150 mm
200 mm
250 mm
300 mm
0 mm
60.3
2.9
4.1
4.6
3.5
3.1
2.8
2.5
2.1
1.9
63.5
2.9
4.3
4.7
3.7
3.2
2.9
2.6
2.2
2.0
70.0
2.9
4.8
4.9
3.9
3.5
3.1
2.7
2.5
2.2
76.1
3.2
5.8
5.1
4.1
3.7
3.4
3.1
2.8
2.5
88.9
3.2
6.8
5.6
4.5
4.1
3.8
3.5
3.2
2.8
101.6
3.6
8.7
6.0
5.0
4.5
4.2
3.9
3.7
3.4
108.0
3.6
9.3
6.1
5.2
4.7
4.4
4.1
3.8
3.5
114.3
3.6
9.8
6.3
5.3
4.9
4.5
4.2
4.0
3.7
127.0
4.0
12.1
6.7
5.7
5.3
4.9
4.6
4.3
4.1
133.0
4.0
12.7
6.8
5.9
5.4
5.1
4.7
4.5
4.3
139.7
4.0
13.4
7.0
6.0
5.6
5.2
4.9
4.6
4.4
159.0
4.5
17.1
7.5
6.5
6.1
5.8
5.4
5.1
4.9
168.3
4.5
18.2
7.7
6.8
6.3
6.0
5.6
5.3
5.1
193.7
5.6
26.0
8.3
7.4
7.0
6.7
6.3
6.1
5.8
219.1
6.3
33.1
8.8
8.0
7.6
7.3
6.9
6.7
6.4
244.5
6.3
37.0
9.3
8.5
8.1
7.7
7.4
7.1
6.8
273.0
6.3
41.4
9.8
9.0
8.6
8.2
7.9
7.6
7.3
323.9
7.1
55.5
10.7
9.9
9.5
9.2
8.9
8.6
8.3
355.6
8.0
68.6
11.2
10.5
10.1
9.8
9.5
9.2
8.9
406.4
8.8
86.3
12.0
11.3
10.9
10.6
10.3
10.0
9.7
457.0
10.0
110.2
12.7
12.0
11.7
11.4
11.1
10.9
10.6
508.0
11.0
134.8
13.4
12.8
12.5
12.2
11.9
11.6
11.4
610.0
12.5
184.2
14.7
14.1
13.8
13.5
13.3
13.0
12.8
D.8 Pipework
Fig. D.8.4–8
d mm
e) Support spans in (m) - welded steel pipe (d x s) - empty pipe and insulation thickness (Dd)
s mm
qM kg/m
Dd =
50 mm
100 mm
150 mm
200 mm
250 mm
300 mm
0 mm
60.3
2.9
4.1
4.6
3.5
3.1
2.8
2.5
2.1
1.9
63.5
2.9
4.3
4.7
3.7
3.2
2.9
2.6
2.2
2.0
70.0
2.9
4.8
4.9
3.9
3.5
3.1
2.8
2.5
2.2
76.1
2.9
5.2
5.1
4.1
3.7
3.3
3.1
2.7
2.4
88.9
2.9
6.2
5.6
4.5
4.0
3.7
3.4
3.1
2.7
101.6
2.9
7.1
6.0
4.9
4.4
4.0
3.7
3.5
3.1
108.0
2.9
7.5
6.2
5.0
4.6
4.2
3.9
3.6
3.2
114.3
2.9
8.0
6.3
5.2
4.7
4.4
4.1
3.8
3.4
127.0
3.2
9.8
6.7
5.6
5.1
4.7
4.4
4.2
3.9
133.0
3.2
10.2
6.9
5.7
5.3
4.9
4.6
4.3
4.0
139.7
3.2
10.8
7.0
5.9
5.4
5.0
4.7
4.4
4.2
159.0
3.2
12.3
7.5
6.3
5.9
5.5
5.1
4.8
4.6
168.3
3.6
14.6
7.7
6.6
6.2
5.8
5.4
5.1
4.9
193.7
3.6
16.9
8.3
7.1
6.7
6.3
5.9
5.6
5.3
219.1
4.0
21.2
8.8
7.7
7.3
6.8
6.5
6.2
5.9
244.5
4.0
23.7
9.3
8.2
7.7
7.3
6.9
6.6
6.3
273.0
4.0
26.5
9.9
8.7
8.2
7.8
7.4
7.1
6.8
323.9
4.0
31.6
10.8
9.5
9.0
8.6
8.2
7.8
7.5
355.6
4.0
34.7
11.3
10.0
9.5
9.0
8.6
8.3
8.0
406.4
5.0
49.5
12.1
10.9
10.4
10.0
9.6
9.3
9.0
457.0
5.0
55.7
12.8
11.6
11.1
10.7
10.3
9.9
9.6
508.0
5.0
62.0
13.5
12.2
11.8
11.3
10.9
10.6
10.2
559.0
6.0
81.8
14.1
13.0
12.6
12.2
11.8
11.4
11.1
610.0
6.0
89.4
14.8
13.6
13.2
12.8
12.4
12.0
11.7
660.0
6.0
96.8
15.4
14.2
13.7
13.3
12.9
12.5
12.2
711.0
6.0
104.3
16.0
14.7
14.3
13.8
13.4
13.1
12.7
762.0
6.0
111.9
16.5
15.3
14.8
14.4
14.0
13.6
13.2
813.0
6.0
119.4
17.1
15.8
15.3
14.9
14.4
14.1
13.7
864.0
6.0
127.0
17.6
16.3
15.8
15.3
14.9
14.5
14.2
914.0
6.0
134.4
18.1
16.7
16.3
15.8
15.4
15.0
14.6
1016.0
6.0
149.4
19.1
17.7
17.2
16.7
16.3
15.8
15.5
216/217
D) Clearances
When routing pipes, attention should be paid
to adequate average spacing between pipe
centres and the building wall, as well as centre
clearances between pipes laid parallel to one
another.
Insulation and built-in pipeline components
(flanges, valves etc.) must remain accessible
at all times. Based on empirical values and
applicable in practice, the following are
recommended for initial design considerations:
Fig. D.8.4–9
Initial design considerations
Note
Wall clearance (mm) with flange and/or valve
Nominal diameter (DN)
25
32
50
65
80
100
125
150
200
250
300
400
500
Without insulation
150
150
150
150
150
200
200
200
250
300
300
400
450
With insulation
200
200
200
200
200
250
250
300
350
400
450
450
600
Minimum clearance
between insulation and
wall approx. 50 mm.
Wall clearance (mm) without flange and/or valve
Without insulation
150
150
150
150
150
200
200
200
250
300
300
350
400
With insulation
200
200
200
200
200
250
250
250
300
350
400
400
450
(Source: Mannesmann)
Fig. D.8.4–9
Initial design considerations
Note
Centre clearances between uninsulated pipes
DN
DN
25
40
50
80
100
150
200
250
300
350
400
450
500
500
380
380
430
430
465
505
530
555
580
610
635
660
685
180
25
450
355
355
405
405
430
455
505
530
555
580
610
635
200
185
40
400
330
335
380
380
405
430
480
505
530
555
580
215
210
190
50
350
330
330
355
355
380
405
455
480
480
505
265
240
230
215
80
300
305
305
330
355
355
380
405
455
480
305
285
260
255
235
100
250
280
280
305
305
330
355
380
405
360
335
310
290
280
265
150
200
250
250
280
280
305
330
355
435
395
370
350
325
315
300
200
150
225
225
225
250
250
280
485
460
425
395
375
360
345
325
250
100
200
220
220
225
225
555
520
495
460
430
410
385
380
365
300
80
175
175
175
200
590
575
540
510
475
450
425
400
395
380
350
50
150
150
175
680
645
630
595
565
530
505
480
455
450
435
400
40
150
150
730
695
660
645
610
580
545
520
495
475
465
460
450
25
150
790
765
730
695
680
645
615
580
555
530
510
500
460
500
500
450
400
350
300
250
200
150
100
80
50
40
25
DN
DN
Centre clearances between insulated pipes
(Source: Mannesmann)
„ Minimum
clearance
between insulation
and pipe surface
respectively approx.
50 mm
„ Flanges
are assumed
as being offset to
one another
„ For media
temperatures
> 300 °C, centre
clearances must be
increased by 40 to
50 mm as of DN 50
D.8 Pipework
E) Routing - mountings
In the building and the steam boiler room
respectively:
„Here, pipes should be routed as
rectilinearly as possible (in the case
of natural bends), close to supports
and transverse beams. This facilitates
the installation of necessary supports,
mountings or brackets. According to
the relevant regulations (see chapter
E.1 - installation), attention must be paid
to optimum accessibility, operation,
maintenance and repair of individual
components
On a pipe bridge:
„Outside the building and the steam boiler
room respectively, individual routing is
preferred along the existing external
building wall. When routing several
pipelines (e.g. steam condensate, raw
water and fuel pipes) from building to
building over a "larger" distance, so-called
pipe bridges should be employed
Mountings:
Taking account of necessary support spans, with
reference to the expansion compensation that
must be ensured, a diverse range of mounting
designs are implemented in practice. Depending
on the forces and torques to be supported, a
demand-dependent decision is made between:
„Friction bearing designs,
such as pipe clamps and pipe bearings
clamped with bearing slides
„Friction bearing designs, force-guideda),
as above, but "blocked" in one direction of
motion (x and/or y direction)
„Fixed-point bearing designsb),
for example clamped with bearing slide
and/or welded together with bearing slide
("blocked" in x, y and z directions)
„Sprung mountings, implemented in
the form of support and/or suspension
mountings as an alternative version of
friction bearing design for the purpose
of absorbing a structurally verified
vertical movement (+/- z direction) at the
mounting point
Fig. D.8.4–10
a)
Friction bearing - positively guided,
guide spacing (LSBG) according to
empirical formula:
LSBG ≈ 0.08 x DN (in m);
for example, nominal pipe diameter
DN 125; provision of a positively
guided bearing design every
LSBG ≈ 0.08 x 125 = 10 m for
the purpose of preventing pipe
"deflection" in the y direction.
b)
Maximum distance between fixed
points in [m] (rectilinear standard
value) in the case of angular and
U-bend expansion joints. See
Fig. D.8.4-10.
Mounting components
DN
≤ [m] for: Angular ≤ [m] for: U-bend
expansion joint
expansion joint
50 to 80
50
100
100 to 150
70
140
200 to 250
80
160
300 to 350
90
180
≥ 400
100
200
218/219
D.8.5
Notes on design engineering of
selected pipework systems
In the following, only pipework within the
steam boiler room is considered. Statements
and information provided are equally applicable
to pipework systems outside the installation
room, especially to those bearing steam
and condensate. With particular reference
to compliance with requirements according
to AD 2000 regulations - datasheet HPOR
Clause 7.4
A) Routing of pipework in the areas of
operating and maintenance gangways
must ensure unrestricted access in terms
of compliance with headroom (according
to TRD 403 ≥ 2000 mm) and passage
height requirements. Routing of pipes
directly above top edge floor (in the form
of so-called "trip pipes") must be avoided. A
conceivable alternative would be to lay or
route the pipes in ducts.
B) Regarding appropriate material selection
with reference to the respectively expected
operating temperatures, operating
pressures (see chapter D.8.1.4) and rated
pressure stages, the specifications and
recommendations detailed in chapter D.8.2
must also be observed.
D.8.5.1
Steam pipes / steam distributors
Aside from suitability, one of the most
important aspects in designing steam
pipework systems and routing steam pipework
is the operational reliability. Hence, the
following recommendations are made on the
basis of available empirical values:
A) In principle, steam pipes must be routed
sloping downwards in the flow direction
towards the required permanent drainage
point (see below in B).
This applies equally to heating steam and
saturated steam pipes with a slope of no
less than 1:200 to 1:100 or 0.5 to 1 %.
The steam pipes of a single or multi boiler
system are normally routed to a (common)
steam distributor. The consumer pipes on the
customer side should be connected here, in
line with requirements, along with those for
internal system demands (thermal deaeration
system, space heating etc.) including spare
connections, a connection for plant metrology
and connection to a permanent drainage
point (see steam distributor diagram for a
recommended design).
Note
„ Do
not select
a lesser slope,
otherwise drainage
of the pipe sections
would be hardly, if at
all, possible due to
the permissible pipe
deflection (fperm)
„ In principle, steam
branch lines must
be connected at
the top of the main
steam pipe in order
to prevent ingress
of draining pipe
condensate
D.8 Pipework
Proposed steam distributor design
≥
ØF
2
D3
D4
D5
*)
*)
*)
Hmin
ØF
Ø Fi
V
ØF
2
+275
E
*)
TI
R
*)
Ø Fn
Ø Fi
PI
ØF
K1
D11)
2)
D2
~150
K1
≥
Lmin
D1
+150
2
Fig. D.8.5.1–1
K24)
DN1
DN2
DN1
KH
KT
DN3
EL
Key to Fig. D.8.5.1-1:
D11)
Steam distributor diameter in (mm)
(see Fig. 8.5.1-2)
D22)
Condensate/sludge collector diameter in (mm)
(see Fig. 8.5.1-2)
D3 to D5 Connection internal diameters - steam boiler
feed pipe in (mm)
DN1
Residue drain nominal diameter, sludge and
contamination removal (see Fig. 8.5.1-2)
DN2
Permanent drainage and start-up drainage
nominal diameter (selected: DN 20)
DN3
Condensate drain pipe nominal diameter (selected: DN 25)
TI/PI
Temperature and pressure test port
(local and remote display)
V
Consumer connections (customer)
E
Consumer connections (internal demands)
R
Spare connections (blank flange)
(normally approx. 0.25 x V)
KOA
K1 / K2
Basket and/or dished ends
KH
KT
KOA
Ball valve
Steam trap (normally bimetal controller or ball float)
Condensate drain pipe (feed) into the existing
condensate system
Discharge into central drain network and/or
system mixing cooler
Flange external diameter in (mm)
Flange external diameter "neighbouring"
flanges in (mm)
Insulation thickness in (mm)
EL
ØF
ØFi - Fn
Dd
Hmin3) Minimum flange connection height in (mm) ≥
Lmin
Minimum centre clearances in (mm) ≥
D1
2
ØF
2
+ Dd + 100
+
Ø Fi/n
2
+ 100
220/221
Notes regarding
1) Pipe cross-sectional area
˭
4
[
D12
≈ 1.5 [ pipe cross-sectional area
˭
x (D32 + D42 + D52)
4
2) Central arrangement of the manifold below
the consumer connections (V)
3) Design observing same spindle axle
positions for the shut-off valves for *)
4) Alternative blank flange connection for K2
Fig. D.8.5.1–2
Diameter and internal diameter for residue drainage
D1 (mm)
125
150
200
250
300
350
400
450
500
600
D2 (mm)
80
100
100
100
150
150
200
200
200
250
DN 1
25
25
25
25
32
32
32
32
32
40
Fig. D.8.5.1–3 Steam distributor
D.8 Pipework
B) Drainage points (manual and/or automatic)
are recommended before every change of
direction upwards, at low points, at pipe
ends and approx. every > 25 m to ≤ 100 m
of straight pipe length.
The drainage points are normally connected
to the relevant condensate manifold
and/or condensate collector taking into
consideration the available pressure levels.
The condensate arising from the steam
pipeline drainage point is normally
discharged into the open air due to the
remoteness of the drainage point.
superheated steam (≤ 50 K above saturated
steam temperature), standard drains
are just as suitable as those mentioned
above. Special versions must be selected
for superheating temperatures > 50 K. A
standard drain could still be used if required,
so long as the drain is situated approx. 1 to
2 m from the condensate connection and
the pipe is left uninsulated.
In order to ensure optimum condensate
collection or drainage, the condensate collector
connections are designed to be nearly as large
as the straight-through internal diameter of
the steam-bearing pipe. The specifications in
Fig. D.8.5.1-4 and Fig. D.8.5.1-5 serve as a
engineering aid here.
Preferential use is made here of
thermodynamic steam traps. Float and
thermostatic traps would be better, but
they are much more expensive. For slightly
Fig. D.8.5.1–4
Nominal diameters of the steam and dewatering lines
D1
50
65
80
100
125
150
200
250
300
350
400
450
500
600
D2
50
65
80
80
80
100
150
150
200
200
200
200
200
200
DN 1
20
20
20
20
20
20
20
20
20
20
20
20
20
20
DN 2
20
25
25
40
40
40
40
50
50
50
50
50
50
50
KON
EW2
Fig. D.8.5.1–5
Diagram of dewatering line connection
Steam pipe slope direction 1:100 (1:50)
~75
≥ 250
D1
DN1
D2
DN2
EW1
a)
Impairment to visibility due to
expansion steam and risk of
scalding must be prevented.
Key:
EW1
EW2
KOA
Drain, blow-down into the open
Start-up drainage
Discharge to condensate collector
222/223
C) Ventilation of steam-bearing systems is
normally provided at the end of the steambearing pipe and/or directly upstream of the
consumption connection.
Automatic air vent valves are preferred
in this instance over manual ventilation.
Makes, such as Gestra, and designs, such
as bimetal controllers, diaphragm controllers
and/or float and thermostatic traps are
recommended.
For steam pipes in steam boiler rooms,
no additional venting is necessary since
it is part of the commissioning of the
steam boiler.
Note
An air layer only
1/10 mm thick provides
about the same
resistance to heat
transfer as a 10 mm
thick layer of dirt on
the heating surface.
Furthermore, the
entrained air (or rather
its O2 content) fosters
the corrosion of pipe and
heating surfaces.
D.8 Pipework
D.8.5.2
Condensate pipes and systems
In principle, condensate pipes must be routed
sloping downwards in the flow direction (due
to possible expansion steam content) towards
the condensate collector station (condensate
collector pipe, condensate tank - open vented
or sealed unvented). A minimum slope of
1:100 (1 %) is mandatory.
In the case of supercooled condensate ≤ 95 °C
(no re-evaporation), similar approaches apply
with regard to necessary flow cross-section
sizing as for feedwater and other "hot-running"
liquid media ≤ the respective boiling point (see
chapter D.8.3.2).
Sample calculation 2
Note
Condensate as in sample calculation 1, but with:
With the help of Fig. 8.1.1-1, this results in an
TCON/E
≈ 158 °C before expansion
internal
pipe diameter di ≈ 70 mm.
p CON/E
≈ 5.0 bar before expansion
h'C/E
≈ 0.186 kWh/kg before expansion
TCON/A
≈ 133 °C after expansion
p CON/A
≈ 2.0 bar after expansion
h'C/A
≈ 0.156 kWh/kg after expansion
h''C
≈ 0.758 kWh/kg Enthalpy
of expansion steam
following expansion
૷ DE = 6000kg/h x
The following variables are used in the
equation specified in chapter D.7.2 for
determining the expansion steam flow rate
(૷DE) instead of those used previously:
૷A = ૷CON Condensate mass flow rate [kg/h]
h'A/E = h'C/E Condensate enthalpy before
expansion [kWh/kg] from [Tb. 2]a)
h'A/A = h'C/A Condensate enthalpy after
expansion [kWh/kg] from [Tb. 2]a)
h''D/E = h''C Enthalpy of the expansion steam
in [kWh/kg] from [Tb. 2]a)
(0.186 kWh/kg - 0.156 kWh/kg)
(0.758 kWh/kg - 0.156 kWh/kg)
= 299 kg/h
≈ 15 m/s selected (according to
wDE
D.8.3.1.1 - standard values for
flow velocity)
≈ 0.606 m³/kg (from [Tb.2],
Y''DE
spec. volume)
di = 2 x
√
299 kg/h x 0.606 m3/kg x 1 h
˭ x 15 m/s x 3600 s
= 0.0654 m (selected: DN 65 > DN 40
with the following calculation results for:
K
&(K
&$
૷'( ૷&21[
K
&K
&$
>[email protected]
Sample calculation 1
Condensate where
TCON
≈ 95 °C
૷ CON ≈ 6000 kg/h
w CON ≈ 1.5 m/s (selected according to D.8.3.1-1 standard values for flow velocity)
ˮ CON
≈ 962 kg/m³ (according to [Tb. 2])
GL [
a)
Each as a function of the given
condensate operating pressures.
෭
NJK[K
˭[NJP[PV[V
PVHOHFWHG'1
sample calculation 1)
224/225
For the section of pipework between a
consumer (e.g. heat exchanger) and the steam
trap, standard practice is to select the internal
diameter of the steam trap. Downstream from
the steam trap, the decisive design variable
(due to pressure reduction) for pipe crosssection sizing is the expansion steam flow rate
(૷DE) (see chapter D.7.2, plus Fig. D.8.1.1-1 and
sample calculation 2 in chapter D.8.5.2).
The aforementioned slope in the pipework
should ensure that the condensate pipe drains
in the event of system standstill. For the same
reasons, inlet pipes into the collector should
be inserted from above, if possible in the flow
direction.
The additional provision of non-return valves
is recommended here for the hydraulic
separation of sections of pipework.
Note
Condensates from widely differing pressure
stages should only be brought together
following prior expansion of the hot
condensate.
Low points (so-called water traps) must be
avoided at all costs in the routing of pipework
due to an increased risk of water and frost
damage. System-dependent low points must
therefore be drained completely. All equipment
and valves must be capable of "running dry".
The use of so-called "expansion trap"
condensate drains is recommended,
particularly in external system areas. An
expansion trap condensate drain, which is
set for example to an opening temperature of
around + 10 °C, opens automatically following
system shutdown, as soon as the temperature
drops to close to freezing point.
If elevation of the condensate is required as
a result of the system implementation (for
example, routing of the main condensate
collection pipe above the point where
condensation occurs), the use of socalled condensate lifts and/or condensate
compensators is recommended depending on
the amounts of condensate involved. Elevating
the condensate results approximately in a
notable additional back pressure (PG) that
must be overcome downstream from the
trap of:
pG ≈ 0.15 bar/m + pCON bar, where PCON positive pressure (bar) in the condensate
collector pipe itself.
Note
The function of the condensate drainage
system should be checked at least every six
months (for ineffective steam blow through).
The employment of electronic monitoring
systems is recommended for this purpose,
especially in the case of process-related
large scale consumers on the customer side
(example: Gestra type VKE 26 with NRG 16-27
electrode and NRA 1-3 inspection station with
separate alarm).
Specific additional reference is made to
appropriate manufacturer's engineering
materials for specific applications, in respect of
selecting suitable condensate drain, lifting and
transport systems.
D.8 Pipework
D.8.5.3
Boiler lye and blow-down lines
Pipe routing each from steam boiler
connecting flange to connection and inlet to
lye expander and mixing cooler respectively
(see chapters C.8.1, D.7.1 and D.7.2).
If, in the case of multi boiler systems, the pipes
are routed to a common collector before feeding
into the aforementioned thermal equipment,
attention must be paid to a hydraulic separating
mechanism at the feed-in point (installation of a
non-return valve on each pipe).
Where pipes are connected to a common
collector, attention should also be paid to
implementing the connections from above. The
pipes must be routed with constant adequate
slope in the flow direction. As described in
chapter D.8.5.2, a minimum slope of 1/100
(1 %) must also be ensured in this instance;
the same applies to specifications regarding
pipe cross-section sizing.
In order to minimise hydraulic low-noise media
discharge (particularly for the blow-down line),
the level of the feed-in points on the mixing
cooler should be provided as far as possible
below the feed lines (mixing cooler positioning
sunk below upper edge of the floor). Due to
expected slight vibration and water hammer
during operation, the pipes must be held
in place securely by means of positive
guides (force-guided friction bearing - see
chapter D.8.4).
Particular attention should be paid to
unrestricted thermal expansion (structurally
"soft" routing with an adequate number of
natural pipe bends), whereby the connectors
on the steam boiler and the thermal equipment
must not be excessively stressed.
Note
With reference to only relatively short pipe
lengths, pipe cross-section sizing under
consideration of actual expansion steam is not
recommended. Draining therefore takes place
in the pipe in the form of a twin-phase flow
with specific phase separation (steam/water)
in the lye expander or mixing cooler. Straightthrough internal diameters for the respective
pipe must be selected in accordance with the
connecting valve on the steam boiler.
If the blow-down line needs to be routed
more than 1 m vertically upwards in order to
minimise water hammer, draining of the line
at the lowest point is always recommended
before every blow-down process.
226/227
D.8.5.4
Feedwater - softened water drinking water
Necessary routing for:
A) Feedwater - suction line
„From feedwater tank to connecting flange
(suction side) of the boiler feedwater pumps
„On routing, a constant downwards slope
and the necessary feed pump inlet height
(see chapter D.6) must be observed
„Taking account of adequate expansion
compensation as a function of the
permissible stresses (lateral forces and
moments) for the pump inlet manifold
in accordance with manufacturer
specifications, if applicable, verification
necessary during engineering
„Provision of a drainage option at the pipe
low point of at least DN 20
„Pipe cross-section sizing according to
chapter D.8.3.1 taking account of any
applicable permissible total pressure loss
of ≤ 0.5 mWC
B) Feedwater - pressure line
„From boiler feedwater pump pressure port
to feedwater inlet connector on the steam
boiler and/or to the ECO connector in the
case of ECO operation
„Provision of ventilation points at the pipe
high points and residual water drainage
options at the pipe low points of at least
DN 20
„Taking account of expansion
compensation, as in A), but with reference
to the pressure ports of the boiler
feedwater pumps
„Pipe cross-section sizing, as in A), but with
reference to a total pipe pressure loss up
to steam boiler inlet of ≤ 0.1 x pB (with pB =
steam boiler operating pressure), whereby
the boiler feedwater pump pressure at zero
head (maximum possible pump delivery
pressure according to pump curve), which
can be higher than the operating pressure
(operating pressure ≈ 1.1 x pB, see chapter
D.6), should be used as the basis for the
wall thickness calculation
C) Raw water - drinking water line
„From the customer-side connection
point up to connection to the selected
project-side CWT system (chemical water
treatment system), in compliance with
the necessary nominal pipe connection
diameter (see also information in chapter
D.8.3.1 - standard velocities)
„Pump-side implementation of a non-return
device with respect to the customerside connection point in accordance with
DIN 1988 by means of a non-return valve
„Assurance of necessary water flow rate
according to CWT type (see chapter
D.4.3.1) at a minimum flow pressure of
3.0 a) bar and a maximum pressure of
6.0 bar that must not be exceeded
„Provision of residue draining points
(dewatering) of at least DN 15 to DN 20 at
applicable pipe low points
„Expansion compensation considerations
are irrelevant due to media temperature
< 20 °C
D) as in C), but with mixing cooler connection
„As a branch line from C) with branch
connection point downstream from the
non-return device in the flow direction,
guaranteeing the necessary cooling water
flow rate according to chapter D.7.1
a)
Not including the back pressure
from the thermal water treatment
system.
D.8 Pipework
E) Softened water line
„From CWT system to connector on the
deaerator
„Provision of an additional non-return valve
in the flow direction at the end of the line,
directly upstream of the deaerator inlet
„Pipe connection nominal diameters (crosssection sizing), minimum flow pressure
and expansion compensation as in C)
Fig. D.8.5.4–1 Ventilation/drainage line routing
Slope
Venting
F) Ventilation/drainage line routing
„In order to entrain an air bubble in the
flow, a minimum flow velocity ≥ 0.3 m/s is
required for horizontal pipes
„Lines to ventilation equipment must be
routed with an incline
1 : 200
Drain pipe routing:
„The minimum internal diameter for drain
valves should be selected in such a way
that "dirt" (mechanical contamination) can
also be discharged. In practice, nominal
diameters of at least DN 20 and selfcleaning valve seats have therefore proven
to be effective. If need be, it should be
possible to break through the valve (ball
valve). Lines to drainage facilities must be
routed with a fall
„Drainage and ventilation lines should be
visible by routing them via a common
tundish, with central discharge into the
existing customer-side floor drainage
system
Slope
1 : 100
Drain
(dewatering)
228/229
D.8.5.5
Exhaust vapour, waste steam
and discharge pipes
Necessary routing for:
A) Exhaust vapour line
„From thermal deaeration system in the
case of routing outside the building
(via roof)
„Line routing with constant incline in flow
direction
„Line routing as short and straight as
possible with sufficient expansion
compensation
„Pipe cross-section sizing with a
recommended nominal diameter expansion
above than the specified nominal deaerator
connection diameter, but taking account
of total pressure losses that must not be
exceeded of ≤ 0.5 x pB/E (where pB/E is the
available deaerator positive pressure) and
maximum exhaust vapour output (૷ S/V )
according to chapter D.7.3
(see also chapters D.7.1 and D.8.3.1) from:
di(req) ≥ 2 x
√
૷ a/DE x Y''S
ZS(MAX) x ˭
[m]
with calculation variables for:
„Maximum blow-down amount ૷ a ≈ 7.5 kg/s
„Operating pressure (pB)
≈ 13 bar
„Expansion to atmosphere
≈ 0 bar
„Proportion of re-evaporation (fDE) from [G2 Tb.6]
of 17 %, corresponding to ฬ
0.17 kg steam /kgblow-down amount
„Expansion steam output - ૷ a/DE = ૷ a x fDE
= 7.5 kg/s x 0.17 kg steam/kgblow-down amount
= 1.275 kgsteam/s
„Specific volume Y''S of the expansion
steam at atmospheric pressure
from [Tb. 2]
= 1.694 m³/kg
„Maximum selected flow velocity
limit w S(MAX)
B) Ventilation - steam vapour - lines
„For condensate tank (open unvented),
partial deaeration system and mixing
cooler, the lines must be routed with a
constant incline (via roof, outside building)
from the connecting flange on each device
„Line routing also as short and straight
as possible with sufficient expansion
compensation
„Pipe cross-section sizing respectively in
accordance with the connectors (nominal
flange connection diameters) specified
here on the manufacturer side
Note
Sample calculation 1
≈ 70 m/s
(see note regarding 1) in chapter D.8.3.1)
the required internal diameter for the ventilation line is:
di(req) ≥ 2 x
√
1.275 kg/s x 1.694 m3/kg
70 m/s x ˭
≥ 0.198 m
Note
With reference to a permissible positive
pressure of 0.5 bar for the mixing cooler, this
results in
di(req)(0.5 bar) where Y''S(0.5 bar) ≈ 1.159 m³/kg of:
GLUHTEDU
ุ[
෭
NJV[PNJ
PV[˭
ุP
and corresponds to the Viessmann factory
specifications of DN 150.
The cross-section sizing
for the mixing cooler
ventilation line must
reliably cope with the
discharge of the actual
expansion steam from
the steam boiler blowdown process "without"
any appreciable back
pressure to be expected.
D.8 Pipework
C) Safety valve (SV) - discharge pipes for:
„SV steam boiler
„SV thermal deaeration system
„SV economiser (if available and fitted with
shut-off devices)
„SV steam superheater (if available and
fitted with shut-off devices)
each routed from SV connecting flange
with constant incline (via roof, outside
building)
„Discharge pipes must be routed as short
and straight as possible with sufficient
expansion compensation
„Discharge pipes must terminate without
risk to bystanders
„No liquid (condensate, rainwater etc.)
may accumulate in the discharge system,
which must therefore be equipped with a
dewatering line at the pipe low point (see
drawing) that cannot be shut off
Fig. D.8.5.5–1
Discharge system
DNL
Note
SV blow-off silencer
When blowing off safety
valves (particularly steam
boiler SV), unacceptable
noise emissions may
occur at the outlet
points, depending on
the blow-off pressure
and discharge amount.
Short-lived sound
pressure levels in the
range 120 to 132 dB(A)
can be expected.
According to regulatory
requirements (TA-Lärm),
employment of steam
blow-off silencers
with attenuation
values (ΔdB(A)) of
30 to 50 dB(A) is
recommended.
EXR
„On the outlet side, it is recommended that
the discharge pipe is increased in size by at
least one nominal diameter (see drawing),
although the following notes must also be
considered:
- Discharge of the steam mass flow (૷ FS),
without the respective permissible
operating pressure increasing at the same
time by more than 10 %
- Safety valve
=> saturated steam boiler ≥ ૷ FS
(as boiler output)
- Safety valve
=> superheater ≥ 0.25 x ૷ FS
- Safety valve
=> thermal deaeration ≥ ૷ FS
(as required amount of heating steam see chapter D.10.2)
„Diameter DNL and length of pipe, existing
bends and other inbuilt parts (silencer
maybe), should also be sized in such a
way that the back pressures specified by
the manufacturer for the respective SVs
are not exceeded and the required steam
mass flow can therefore be discharged
safely
„Back pressure > 0.15 x pA (where pA is
the set SV discharge pressure) should
therefore not be exceeded
DNA
Distance from
connector to weld
seam must be
Together with the previously mentioned
noise emission from the valve, the expected
noise load is largely determined by the outlet
velocity. Hence, the maximum velocity
specified in chapter D.8.3.1 should not be
exceeded.
approx. 50 mm
Key:
DNA SV outlet nominal diameter
DNL Discharge pipe SV nominal diameter
(recommended: DNA + 1 x increase in
nominal diameter)
DNE Drainage nominal diameter
(recommended.: DN 15 to DN 25)
EXR Eccentric reduction in nominal diameter
The discharge pipes must be sized and
routed, taking into consideration the given
operating conditions, in such a way that the
static, dynamic (reaction and/or repulsive
forces) and thermal loads are absorbed safely.
Corresponding documentation must be
maintained here on the engineering side.
It is recommended that the safety valve(s) is/
are mounted accordingly as (a) fixed point(s).
Appropriately designed sprung supports
(see also chapter D.8.4) should be used to
compensate for any vertical movement in
the pipes. The installation and assembly
instructions from the respective safety valve
manufacturer must also be observed.
230/231
Information regarding routing via the roof
Roof outlet with thermally insulated, silenced
slide coupling (vertical friction bearing) and
protection against precipitation (rain collar).
Single and/or double-sided obtuse-angled
outlet terminal (see Fig. D.8.5.5-2/3/4):
Fig. D.8.5.5–2 Version A
Note regarding regulations
that must also be observed
TRD 421, particularly Clause 6, and
DIN EN 12953-8, particularly Clause 4.2.
Fig. D.8.5.5–3 Version B
'1/
'1/
~ 120
°
~ 120
°
)5
'1/
'1/
Fig. D.8.5.5–4 Version C
With version B preferred
If version A is selected, the bending moment
arising due to the power of repulsion FR at the
roof outlet must be considered.
Version C
Wall outlet with thermally insulated, silenced
slide coupling (horizontal friction bearing).
FR
DNL
Disadvantages:
Provision must be made for installation and/or
retrofitting of a silencer.
Increases the bending moment to be absorbed
by the vertical pipe leg.
External wall
DNL
D.8 Pipework
D.8.5.6
Fuel lines
A) General information
„Pipes are considered from each point of
entry into the building up to connection to
the combustion system valve train for extra
light fuel oil and natural gas (E)
„Design of the respective connection
sizes according to specifications for the
combustion system to be implemented
(gas and/or fuel oil combustion) as a
function of the required combustion output
according to chapter D.3.3.1
„Sizing the feed pipes with reference to the
recommended standard values for flow
velocity according to chapters D.8.3.1
and D.8.3.2
„Design of the fuel oil line from the
customer-side fuel oil tank to the
combustion system and back to the fuel
oil tank as a so-called ring pipeline. The
fuel oil circulating through the ring pipeline
is maintained at a constant pressure of
between 1.0 and 2.5 bar by appropriately
sized pressure control valves
„Recommended sizing of the ring pipeline
for approx. 1.5 to 2.5 times (depending
on system size) fuel demand સ B, with
the higher supply rate (including spare
capacity) being the design basis for the
feed pump to be provided on the customer
(project) side
„Combustion-side (burner) connection
to the ring pipeline via so-called gas/air
separator that must be sized accordingly
on the project-side
„Ventilation and drain lines (recommended:
DN 15 to DN 20) must be discharged into
sealed unvented tanks (such as slop tanks)
in a controlled manner (in accordance
with [German] Water Resources Act) and
supplied to a form of reuse (via pump
return feed)
„The ventilation and discharge pipes
from the gas valve section(s) must be
routed separately, in accordance with
manufacturer specifications, with a
constant incline to the building exterior
(exterior wall outlet preferred)
„If dewatering devices are necessary on the
gas line (due to expected gas condensate,
if applicable), any escaping gas must also
be dissipated safely
„Pipe supports and the spacing thereof
must be designed in accordance with
chapter D.8.4
„Expansion compensation must be ensured
by the expected natural pipe bends in
the system and for unexpected ambient
temperatures > 40 °C
B) Specific information for extra light fuel oil
(HEL) lines
„With reference to the Pressure Equipment
Directive 97/23/EC, the fluid (HEL) is
assigned to Group 2
„With expected pressures ≤ 3.0 bar
and expected straight-through nominal
diameters significantly < DN 100, the
pipework system (assignment) is executed
according to Article 3 Paragraph 3, which
states: "In the case of good engineering
practice..." (see also notes in chapter
D.8.1.3)
„"Good" engineering practice is considered
to have been delivered subject to
compliance with and implementation
of regulation TRD 411 - Oil combustion
systems on steam boilers, in particular
Clauses 6.1, 6.2, 6.3 and 7.1 - safety shutoff devices, as well as:
DIN EN 12953-7, particularly Clauses 4.2
and 4.3 with reference to DIN EN 267 Pressure-jet oil burners
C) Specific information on gas lines
„With reference to the Pressure Equipment
Directive 97/23/EC, the fluid (natural gas E) is assigned to Group 1
„With expected pressures ≤ 4.0 bar
and expected straight-through nominal
diameters significantly > DN 25 to
≤ DN 350, the pipework system
(assignment) is implemented according
to Categories I to II, or Category III for
straight-through nominal diameters
> DN 350 (see also notes in chapter
D.8.1.3)
„The regulations TRD 412 - Gas combustion
systems on steam boilers, in particular
Clauses 4 and 5.1 - shut-off devices
outside the boiler installation room,
must also be observed, as well as
DIN EN 12953-7, particularly Clauses 4.2
and 4.3 with reference to DIN EN 676 Pressure-jet burners for gaseous fuels
232/233
D.8.5.7 Waste water and
floor drainage systems
It must be possible to drain the technological
waste water arising in the system safely via an
on-site (customer-side), centrally implemented
drain network, according to the rules of good
engineering practice.
Suitable drainage facilities (floor traps) must be
provided for this purpose on the project side
at the locations described in the following.
The fall of the pipes (ground pipes) should be
selected to be no less than 1:50 (2 cm/m) in
the flow direction.
A) Steam boiler
Positioning at the end of the steam boiler
approx. 500 mm to the right (from burner
viewpoint), next to the base frame, with a
recommended inlet of DN 100 for feeding in:
„Incoming flue gas condensate (short-lived
from the steam boiler system start-up
phase)
Note: (see also chapter D.2.3.3), Flue gas
condensates with a pH value < 6.5 must
always be routed through a neutralising
system (to be provided on the project side)
before entry
„Incoming condensates from the discharge
pipe safety valve
„Ventilation facilities, feedwater line drains
„Steam boiler ventilation
„Blow-off and dewatering line from
manostats, distributors and reflection
water level
„Drainage, waste water from sampling
cooler (intermittent, maximum once per
8 h shift at ≤ 0.25 l/s)
„Economiser ventilation/drainage
Note
B) Feedwater tank - condensate tank
Positioning subject to the selected location
(installation plan) directly at the overflow
pipe exit with a recommended point of
entry ≥ DN 100 to ≤ DN 125, depending on
system size, for feeding in:
„Incoming overflow outputa)
„Any necessary containerb) and/or tank
contents in the event of repair and
maintenance
„Incoming condensates from the discharge
pipe safety valve
„Blow-off and dewatering lines from level
displays
„Drainage (draining residue) from feedwater
suction line
„Drainage from boiler feedwater pumps
The points of entry
must also be capable
of accepting any
waste water from the
sanitation area (e.g.
spray water from
floor cleaning).
a)
Maximum expected overflow rate
in kg/h ≤ 0.5 x ૷FS (where ૷FS is the
steam boiler output in kg/h).
b)
See Fig. D.4.1.2-1.
D.8 Pipework
C) Mixing cooler - lye expander
Positioning subject to the selected location
(installation plan) directly at the mixing
cooler outlet pipe exit with a recommended
point of entry ≥ DN 100 to ≤ DN 150,
depending on system size, for feeding in:
„Any necessary residual drainage of
tank content (mixing coolera) and/or
lye expander)
„Any necessary residual drainage from the
steam boiler
„The continuously incoming waste water
output (૷ A in kg/h) from the mixing
cooler (see also chapter D.7.1) depending
on steam boiler output (૷ FS in kg/h),
the necessary T.D.S. rate (A in %), the
T.D.S. water temperature (TA in °C) as
inlet temperature into mixing cooler, the
selected waste water outlet temperature
(T WW/A in °C) from the mixing cooler and
the actual cooling water temperature
(TCW in °C) as inlet temperature into mixing
cooler, from:
a)
Container capacity, see chapters
D.7.1/D.7.2.
૷$ ૷)6[
$
7$7::&
7::&7&:
NJK
(disregarding the only intermittent blow-down
output (૷a), for example:
૷FS = 25,000 kg/h;
A = 5 %
TA = 105 °C
TWW/C = 30 °C
TCW = 15 °C => ૷A ≈ 7500 kg/h
as before, however, with:
૷FS
= 4000 kg/h; => ૷A ≈ 1200 kg/h
as before, however, with maximum
3 x 25,000 kg/h
≈ 22,500 kg/h
૷A
Notes regarding the sample calculations:
This should be subjected to a repeated
plausibility check for the recommended inlet
DN range. At a T.D.S. rate of A > 3 % to
≤ 6 %, the size of the point of entry must
be increased, in the case of maximum boiler
output (૷FS ≥ 25 to ≤ 75 t/h), to DN150 and/or
an additional lye cooler (waste heat utilisation)
is advisable according to the amortisation
calculation in chapter D.7.1, with the objective
of minimising the necessary cooling water
requirement.
234/235
D) Chemical water treatment system (CWT)
Positioning subject to the selected
location (installation plan) directly (approx.
500 mm) in flow direction upstream of the
"open air" waste water connection with a
recommended point of entry, depending
on CWT size, ≥ DN100 to ≤ DN125 for
expected intermittent amounts, once per
system regeneration and full-load operation
once per shift (7 to 8 h), in accordance
with the following tabular specifications
(approximate):
Fig. D.8.5.7–1
Size of the CWT in case of incoming waste water
Size (see also Viessmann datasheet)
Amount of flushing water per regeneration (m³)
Flushing water throughput (m³/h)
Fig. D.8.5.7–2
60
120
200
320
400
500
0.11
0.22
0.375
0.6
0.75
0.9
0.3
0.5
0.5
0.9
0.9
1.2
Size of the CWT in case of incoming waste water
Size (see also Viessmann datasheet)
Ventilation
drainage
lines
(residual(m³)
Amount ofand
flushing
water per
regeneration
drainage) must also be fed into the design
Flushing water throughput (m³/h)
point of entry.
600
800
1000
1400
3000
4500
1.1
1.42
1.82
2.55
5.5
8.0
1.6
1.6
2.7
2.7
5.8
7.5
E) Reference to regulations
During the engineering of the central drain
network, appropriate preventive measures
must be taken, with respect to possible use
of "fuel oil" as the fuel, against discharge of
fuel oil (in case of accident, leakage etc.)
into the drain network (for example, use of
floor inlets with fuel oil traps).
In principle, standard works, such as:
„DIN 1986 - Drainage systems on private
ground - Part 100: Specifications in relation
to DIN EN 752 and DIN EN 12056
„DIN 1999 - Installations for separation of
fuel oil, in conjunction with DIN EN 858
„DIN 4043 - Traps for light liquids (fuel oil
traps) must be observed
D.9 Flue system
Flue system
The flue system, with connection to the flue outlet of the steam boiler, usually
consists of the continuously rising flue pipe with built-in parts up to the system
chimney connection (stack).
Built-in parts, in this instance, are considered
to be the necessary deflections (bends),
expansion joints, silencers and flue gas
dampers with actuators for isolating the steam
boiler on the flue gas side and/or controlling
flue gas pressure (combustion chamber
pressure regulation).
Flue systems must be designed in accordance
with national and local regulations, as well as
the relevant standards. General requirements
for flue systems in and on buildings are
specified in DIN EN 1443. The design must
comply with the applicable national building
regulations, DIN 18160 and TRD 403 Clause 7.
Apart from the building regulations, DIN 1056,
DIN 4133 and DIN EN 13084-1 apply in the
case of freestanding chimneys. Hydraulic
measurements must be carried out in
compliance with the standards DIN EN 13384
and DIN EN 13084 (for freestanding chimneys).
The following sections contain general
recommendations for the design of flue
systems, which guarantee uninterrupted
operation of the combustion system
employed.
Non-observance of these rules could lead
to the occurrence of, in part, substantial
operational problems. Frequently, these
are acoustic faults and/or impairments of
combustion stability or excessive vibration of
parts and/or their components.
236/237
D.9.1
„Deflections in the connection pieces
must be designed for optimum flow with
appropriate pipe bends (≤ 90° pipe bends)
„Connection pieces with several deflections
should be avoided, since they have a
negative impact on air and structure-borne
noise, as well as the "start-up pressure
surge" (combustion back pressure)
„A transition angle of ≤ 30° is
recommended for any necessary
transitions (reductions/expansions) from
round to angular connection, e.g. silencer
connection and/or chimney
„The material used for the connection
pieces (including built-in parts) must be
suitable for a flue gas temperature of up
to 350 °C
Planning and design information for
connection pieces
The flue gas from the combustion system
must be routed directly to the chimney with
as little pressure and heat loss as possible.
The connection pieces to the chimney must
therefore be designed for optimum flow
(rectilinear, short and rising with a minimum
number of deflections) and with appropriate
thermal insulation (see [A2]).
Any arising thermal expansion and reaction
forces on the chimney must be compensated
by the installation of expansion joints (here
with the preferred use of fabric expansion
joints due to the unreliable reaction forces to
be expected) or slide couplings.
Due to their excellent vibration and pressure
resistance, the use in principle of pipes
(welded pipe according to DIN EN 10217-2
and/or rolled as cylinder jacket pipe) in the
wall thickness range ≥ 4.0 to ≤ 8.0 mm is
recommended.
The internal diameters (straight-through
nominal diameters) of the flue pipe (connection
pieces) must be selected in accordance
with the flue gas connection diameter of the
respective steam boiler (see Fig. D.9.1-1).
Fig. D.9.1–1
Flue outlet diameter of the Vitomax steam boilers
Steam boiler output (૷FS) (t/h)
Flue gas connection
internal diameter (mm)
0.7
1.15
1.75
2.9
4.0
6.0
8.0
11.0
14.0
18.0
22.0
to
to
to
to
to
to
to
to
to
to
to
0.9
1.4
2.3
3.8
5.0
7.0
10.0
12.0
16.0
20.0
25.0
240
290
340
440
600
700
800
900
1000
1100
1200
D.9 Flue system
Note
In the case of intended falling below the dew
point (utilisation of condensing technology see specifications in chapter D.2.3.3), expected
mediaa) temperatures "permanently" < 90 °C
and a sulphur content in the fuel > 0.2 percent
by weight, the use of corrosion-resistant
materials (stainless steels) is absolutely
essential (DIN 51603).
supports" for straight-through nominal
diameters > DN 800) are the preferred
design here and/or friction bearings with
spring supports (see also chapter D.8.4)
„Test ports (emission test points) must
be provided at suitable locations. The
gas sampling defined in VDI guidelines
(VDI 4200) must be implemented, taking
account of any applicable statutory
specifications
„On installation of a flue gas damper (as
described in the introduction to chapter
D.9), a safety-oriented "OPEN" limit switch
must be integrated into the steam boiler
control system
„During the engineering process, attention
should be paid to allowing the unrestricted
drainage of flue gas condensate along the
whole length of the connection pieces
(also in the chimney itself), as dealt with in
ATV datasheet 251, ensuring its disposal
subject to relevant local provisions
„In order to prevent flue gas discharge at
the dewatering connectors provided for
this purpose, installation of an approx.
100 mm so-called "water trap pipe" is
recommended
„In the event of steam boiler system
standstill and outside temperatures below
freezing, the risk of frost damage must be
prevented
„Cleaning apertures must be provided in
accordance with DIN 18160-1, DIN 18160-5
and IVS Guideline 105, and their installation
positions specified in cooperation with the
responsible flue gas inspector
„Pipe supports (compliance with necessary
support spans) must be provided in
accordance with the required structural
documentation. Friction bearings (if
applicable, in the form of so-called "saddle
Fig. D.9.1–2
Note
Locking of the damper with combustion.
An opened damper is a prerequisite for
commissioning the steam boiler. After
shutting down the system, if applicable,
the end position "damper CLOSED" should
be set in such a way that the damper does
not close tightly (approx. 5 % in "open"
position), so that short-lived residual heat
is allowed to escape from the combustion
chamber via the flue system.
„Wall outlets must be thermally insulated
and protected from the elements in the
form of a sliding mount through a wall
sleeve and skid support (see Fig. D.9.1-2)
Sliding shoe mounting
a)
Assumption, expected media
temperatures ฬ feedwater inlet
temperatures in the unalloyed
economiser (ECO type 100 and/or
type 200).
Key:
WH - Wall sleeve with wall anchor at x)
DNV - Connection piece (pipe) straight-through
nominal diameter
DD WS ΔL GLK -
Required insulation thickness
Weather protection
Pipe sliding movement
Skid (3 x 120°)
238/239
D.9.2
Sizing the flue system
„The basis for flow-related sizing is provided
by standards DIN EN 13384 and/or
DIN EN 13084-1
„In order to prevent flow noises in the flue
system, flow velocities with reference to
the operating volume [in m³/h] and full-load
operation should not exceed 12 to 15 m/s
in practice
„The combustion system is designed in
such a way that the resistances of the
steam boiler on the flue gas side, including
economiser (ECO) plus the expected
resistances for flue pipe and silencer,
can be overcome (see chapter D.9.2-1
and D.9.2-2 resistance values for steam
Note
For a freestanding chimney according to
DIN EN 13084-1, appropriate structural
documentation must be furnished by the
manufacturer. In the final analysis, the resulting
lateral forces and moments at the chimney
base are fundamental for chimney stability,
which must be verified (on-site) on the projectside (sizing the necessary anchor cage and
foundations; provision of a ground survey with
reference to the installation location on the
customer side)
The anchor cage is
designed to provide a
structurally stable support
for the chimney on the
base foundations via
a threaded fastening,
with connection of the
necessary chimney
earthing (lightening
protection) to the conductor
system to be provided on
the customer side.
boilers), so that a manometric pressure
of ± 0 mbar (up to a recommended slight
positive pressure of 1 mbar) is present at
the chimney flue gas inlet connector
Pressure drop on the hot gas side (ΔpHG) as a
function of the steam boiler output (૷FS) with
and/or without economiser operation for the
boiler type:
Fig. D.9.2–1
Boiler type M237 / M73A
ΔpHGa) [mbar]
M73A
૷FS [t/h]
with ECO 200
without ECO
0.5
5
4.5
0.7
6
5
1.0
8
6.5
1.3
9.5
7.5
1.65
11
9.5
2.0
12
10.5
2.5
13.5
11
3.2
4.0
14
16
12
13
Guide values; see datasheet for precise details
Fig. D.9.2–2
Boiler type M 75A
ΔpHGa) [mbar]
M 75A
૷FS [t/h]
with ECO 200
without ECO
5
10
17
6
11
16
7
11
15
9
12
17
10
13
18
12
15
17
14
15
17
17
17
18
22
18
15
25
18
14
20.0
18.5
14.5
22.0
18.5
14.0
25.0
18.5
14.0
Guide values; see datasheet for precise details
a)
Assumption, each plus approx.
1.5 to 5.0 mbar for built-in parts,
including silencer, at flow velocities
between 10.0 and 15 m/s as a
practical guide value.
D.9 Flue system
D.9.3
Chimney connection and design
Freestanding chimneys must be designed
with a structurally supportive outer pipe (made
from unalloyed sheet steel) and a thermally
insulated inner flue (made from alloyed
stainless steel).
„Connection pieces must be inserted into
or connected with the chimney with an
incline in the flow direction at an angle of
≥ 30° to ≤ 45°
„In the case of a design with multiple
connections (see below in chapter D.9.4),
chimney connections opposite one another
or at the same height must be avoided
„Any attachments present at the stack
opening must guarantee unrestricted
emission of the flue gases into the open air
„A separate flue must be included in the
design for each steam boiler
Notes
For chimneys with multiple flues comprising
one supporting pipe and several thermally
insulated inner flues, the height is determined
in principle on the basis of the applicable
TA-Luft for:
„Systems not requiring official approval
(1st German Immissions Order - BImSchV)
by the district flue gas inspector, and for
„Systems requiring official approval
(4/13 BimSchV) by the responsible
[German] Regional Office for Health
Protection and Technical Safety (LAGetSi)
or the responsible factory inspectorate on
the basis of an air/climatological report that
must be prepared
a)
Bracketed expression, conversion
of standard volumetric flow rate
into operational volumetric flow
rate, disregarding the operating
pressures.
The chimney and flue system are designed
on the basis of system-specific flue gas
parameters, such as operational volumetric
flow rate (V̇ FG in m³/h), flue gas temperature
(in °C) and the pressure conditions (positive
pressure) in mbar inside the flue, as well as
the required negative pressure in mbar at the
chimney-flue connector on determination of
the operational volumetric flow rate (V̇ FG) as
follows:
9
ɘ )*
૷)6[5
ˮ)*
[[7)*D[PK]
with the calculation variables:
૷FS Nominal fresh steam output from the
steam boiler (kg/h)
ˮFG Mean flue gas density according to [L4]
≈ 1.345 kg/Nm³
R
Dimensionless factor for determining
the amount of flue gas according to
Vitomax 200 HS datasheet (see table
Fig. D.9.4-1 and Fig. D.9.4-2)
7FG Flue gas temperature in [°C] (see table
Fig. D.9.4-1 and Fig. D.9.4-2) as a
function of the operating steam pressure
with and/or without ECO operation
240/241
Fig. D.9.4–1 Vitomax 200-HS, type M237 / M73A
Operating
Vitomax 200-HS, type M237 / M73A
pressure [pB]
R [-]a)
in bar
TFG in [°C]b)
without ECO
with ECO 100
with ECO 200
without ECO
with ECO 100
with ECO 200
6.0
1.094
1.053
1.032
246
168
126
8.0
1.105
1.060
1.038
256
172
127
10.0
1.1135
1.065
1.042
265
174
129
13.0
1.1235
1.070
1.0475
276
178
132
16.0
1.132
1.075
1.052
284
182
135
18.0
1.137
1.078
1.0535
290
184
137
20.0
1.141
1.081
1.0565
295
187
139
22.0
1.144
1.083
1.058
299
190
141
25.0
1.148
1.086
1.061
308
194
145
Fig. D.9.4–2 Vitomax 200-HS, type M75A
Operating
Vitomax 200-HS, type M75A
pressure [pB]
R [-]a)
in bar
TFG in [°C]b)
without ECO
with ECO 100
with ECO 200
without ECO
with ECO 100
with ECO 200
6.0
1.083
1.0525
1.030
226
168
126
8.0
1.094
1.058
1.037
235
172
128
10.0
1.100
1.063
1.0415
246
174
131
13.0
1.109
1.068
1.045
254
177
133
16.0
1.1175
1.073
1.0485
264
182
136
18.0
1.1235
1.076
1.0525
272
184
138
20.0
1.1265
1.078
1.053
275
187
140
22.0
1.130
1.081
1.054
278
190
142
25.0
1.134
1.084
1.056
287
194
145
Note: Intermediate values linearly
interpolated
a)
Mean values for designing the flue
system according to DIN EN 13384.
b)
At full load (100 %), 3 % O2
in flue gas and feedwater
temperature 102 °C.
D.9 Flue system
D.9.4
Note
The following must not
be connected to multiboiler flue systems:
„Steam boilers
with flue gas
temperatures
> 400 °C
„Liquid gas
combustion systems
„Combustion
systems equipped
with fans, if all the
steam boilers are
not installed in the
same room
Common flue system,
merging of flue gas flows
Several steam boilers (combustion equipment)
may only be connected to a common flue
system, in accordance with DIN EN 12953-7, if
the combustion system in conjunction with the
steam boiler is suitable for such an operating
mode and the following requirements can also
be complied with:
„Sizing of the system for guaranteed
discharge of the flue gases in every
operating state and load case
„Prevention of flue gas inflow into offline steam boilers in the case of positive
pressure operation, e.g. using tightly
closing flue gas dampers
„Constant combustion chamber pressure
conditions in each of the connected steam
boilers and in every operating state
„Minimum flue gas velocities according to
DIN EN 13084-1 (wmin ≈ 0.5 m/s)
Merging of flue gas flows should however
be avoided, since the creation of negative
pressure in the chimney can be impeded in the
event of large reductions in load, e.g. ≤ 30 %.
Flue gases would then no longer completely
fill the chimney and "cold" air could "fall" into
the stack.
If a decision is nevertheless made in favour
of merging, it must be ensured that the flue
gas flows (connection pipes) are merged
unidirectionally in a so-called Y piece
(Fig. D.9.4-1).
The chimney system finally employed for
the project must guarantee reliably stable
system operation, on the basis of the air/
climatological conditions to be expected at the
location, in conjunction with specified flue gas
parameters and system load characteristics.
Documentation (control calculation) of the
draught calculation for the selected chimney
system must be prepared on the project
side in accordance with DIN 13384 and/or
DIN 4705.
The following technical data must be observed
on the project side for the (if applicable)
already selected chimney system, focussing
here on official specifications regarding:
„Compliance with noise emission levels
„Chimney height above ground level
„Immissions forecasts according to TA-Luft
242/243
Fig. D.9.4–1 Y piece
Fig. D.9.4–4
Chimney
Chimney
(dia. internal chimney flue ≥ DN)
Fabric compensator
(DN ฺ DN2 + DN1)
Key:
཰ Chimney
šstack inner
flue ≥ DND
ཱ Fabric expansion joint
ི Y piece
DE1 Steam boiler
connection 1
DE2 Steam boiler
connection 2
Y piece
DN2
Flue gas connection,
steam boiler 2
DN1
a60˚ to 90˚
Flue gas connection,
steam boiler 1
Source: SES
Fig. D.9.4–2 Y piece
Source: SES
Fig. D.9.4–5
Chimney base
Source: SES
Fig. D.9.4–3
Chimney connection
Source: SES
a)
DN >/= DE1 + DE2
D.10 Internal system demand
Internal system demand
With reference to the specifications in chapter C.11, the necessary internal system
demand for electrical and thermal energy must be considered in the project.
In the following, appropriate specifications
are recommended as standard values
and information is provided for a possible
calculation.
D.10.1
The need for a redundant power supply, as
a function of necessary uninterrupted steam
provision (for example, in a hospital), must be
identified by the customer at an early stage
during the project preparations.
Internal electrical system demand
The power supply on the customer side is
generally rated at a voltage level of 0.4 kV
to 0.6 kV and a frequency of 50 Hz with
connection to the central system control panel
provided by the manufacturer. Voltage-related
provision of power to all consumers in the
steam generation system is governed on the
manufacturer side from the aforementioned
central system control panel.
For the purpose of ensuring provision from the
steam generation system in line with demand,
a corresponding list must be prepared within
the project (see following tabular overview
Fig. D.10.1-1).
244/245
Fig. D.10.1–1
List of electrical consumers
Consecu-
Consumer
No. of
Voltage
Output
Control
tive no.
(components)
(pce)
(Volt)
(VA)
signal
Comments
1.0 Componentsa)
1.1
Burner
With and/or without
Type:
inverterb)
4 - 20 mA
1.2
1.3
Combustion air fan
With and/or without
Type:
inverterb)
Flue gas recirc. fan
With and/or without
Type:
1.4
Boiler feed pump
inverterb)
With and/or without
c)
Type:
1.5
Condensate pump (open vented system)
inverterb)
c)
Type:
1.6
Condensate pump (sealed unvented system)
With and/or without
c)
Type:
1.7
inverterb)
HEL pumps
Type:
1.8
Fuel oil preheating
Only if heavy oil used
Make:
1.9
CWT incl. dosing system (I&C technology)
4 - 20 mA
Type:
1.10
TWT (I&C technology)
4 - 20 mA
Type:
1.11
Mixing cooler (I&C technology)
4 - 20 mA
Type:
etc.
(the list can be extended as necessary at any time)
2.0 Actuatorsa)
2.1
Flue gas damper
2.2
Feedwater control valve(s)
2.3
4 - 20 mA
4 - 20 mA
Superheater mixing valve
Type:
Make:
Type:
Make:
Type:
4 - 20 mA
Make:
(if installed)
2.4
Heating steam valve/slider
4 - 20 mA
Type:
Make:
2.5
Blow-down valve
4 - 20 mA
Type:
Make:
etc.
(the list can be extended as necessary at any time)
a)
All equipment (motors, sliders,
valves etc.) and automatic systems
(automatic switching, controllers
and control voltage activators) must
be designed with "on" and "off"
or "open" and "closed" feedback
signals.
b)
In the case of inverter operation,
disruptive circuit feedback in
the form of harmonics must be
prevented.
c)
Prior determination of the necessary
drive output as a function of the
respective pump rate is required
(see chapter D.6.1 - boiler feedwater
pumps and D.6.2 - condensate
pumps) - see also chapter D.10.1.-3.
D.10 Internal system demand
Fig. D.10.1–2
List of electrical consumers
Consecu-
Consumer
No. of
Voltage
Output
Control
tive no.
(components)
(pce)
(Volt)
(VA)
signal
Comments
3.0 I&C systems
3.1
Steam boiler
3.2
Condensate system
4 - 20 mA
Type:
(open)
3.3
Condensate system
(closed)
3.4
External: Emergency stop button
Entrance area
installation room
3.5
External: Leak detector - oil
Fuel depot - customer
3.6
External:
Before entry to
Quick-acting safety valve - gas
installation room
External:
Fuel depot - customer
3.7
Quick-acting safety valve - oil
3.8
etc.
External: Flue gas
Chimney system
emission measurements
(if installed)
(the list can be extended as necessary at any time)
4.0 Lighting and TGA systems
4.1
Installation room lightingd)
4.2
Installation room emergency lightingd)
4.3
Installation room ventilation facilities
etc.
(the list can be extended as necessary at any time)
5.0 Lightening protection systeme)
etc.
d)
According to TRD 403 Clause 10,
with particular reference to accident
prevention regulations "electrical
systems and operating equipment"
(VBG4).
e)
According to TRD 403 Clause 11.2
(DIN 57 185, VDE 0185).
Implementation on the customer side from supply sub-distribution unit
If required
Customer-side implementation if required
(the list can be extended as necessary at any time)
246/247
Overview of expected electrical output (kW) pump motor as a function of steam boiler output
(૷FS) and operating pressure (pB)
Fig. D.10.1–3
Expected electrical output - overview
pB
૷FS in [t/h]
bar
0.7
0.8
1.0
1.3
1.65
2.3
2.9
3.8
4.0
5.0
6
0.25
0.32
0.40
0.50
0.60
0.80
1.00
1.40
1.40
1.80
8
0.33
0.42
0.54
0.66
0.82
1.10
1.36
1.80
1.90
2.30
10
0.41
0.53
0.57
0.82
1.10
1.35
1.70
2.20
1.30
2.90
13
0.53
0.70
0.87
1.10
1.33
1.75
2.20
2.90
3.00
3.80
16
0.66
0.84
1.10
1.30
1.64
2.20
2.70
3.60
3.75
4.70
18
0.74
0.95
1.20
1.50
1.85
2.40
3.00
4.00
4.20
5.30
20
0.82
1.05
1.35
1.65
2.05
2.70
3.40
4.50
4.70
6.00
22
0.90
1.20
1.50
1.80
2.30
3.0
3.70
4.90
5.20
6.40
25
1.03
1.30
1.70
2.10
2.60
3.40
4.30
5.60
6.00
7.30
8.0
10.0
12.0
14.0
16.0
18.0
20.0
22.0
pB
૷FS in [t/h]
bar
6.0
7.0
25.0
6
2.00
2.50
2.80
3.50
4.00
5.00
6.00
6.00
7.00
8.00
9.00
8
2.80
3.20
3.80
4.70
5.60
6.60
7.50
8.00
9.00
10.00
12.00
10
3.50
4.10
4.70
5.80
7.00
8.20
9.40
11.00
12.00
13.00
15.00
13
4.60
5.30
6.10
7.60
9.00
10.70
12.20
14.00
15.00
17.00
19.00
16
5.60
6.60
7.50
9.40
11.00
13.00
15.00
17.00
19.00
21.00
23.00
18
6.30
7.40
8.40
10.50
12.70
15.00
17.00
19.00
21.00
23.00
26.00
20
7.00
8.20
9.40
12.00
14.00
16.00
19.00
21.00
23.00
26.00
29.00
22
7.70
9.00
10.30
13.00
15.50
18.00
21.00
23.00
26.00
28.00
32.00
25
9.00
10.00
12.00
15.00
18.00
20.00
23.00
26.00
29.00
32.00
37.00
Assumptions
„Pump efficiency 75 %
„Supplement for pump shaft output 15 %
„Output values rounded
D.10 Internal system demand
Fig. D.10.2–1
System diagram
D.10.2
TWT
Steam boiler
CWT
Internal thermal system demand
From the heat and mass statement, around
the thermal deaeration system, with the
assumptions:
„Operation without exhaust vapour
condenser
„Operation without feedwater or lye cooler
„Operation with lye expander and waste
steam utilisation
„Specific thermal capacity (cp) of
condensate = feedwater =
- constant ≈ 4.19 kJ/kgK
- or 1.163 x 10 -3 kWh/kgK
a value results for the required amount of
heating steam (૷FS/E) as an internal thermal
demand (Q̇FS/E) from:
4
ɘ )6( 4
ɘ &214
ɘ DGGIZ4
ɘ 94
ɘ 65>N:@
where
Q̇CON
Heat required for heating up the
return condensate in [kW] based on
feedwater temperature (Tfw)
Q̇CON = ૷CON x cp (Tfw - TCON)
Q̇ADD/FW
As for Q̇CON but for heating up the
additional feedwater (softened water
from the CWT)
Q̇add/fw = ૷add/fw x cp (Tfw - Tadd/fw)
Q̇V
Amount of exhaust vapour heat in
[kW] as lost heat (deaerator exhaust
vapour outlet (૷S/V)
Q̇V = ૷S/V x (h''V - cp x Tfw)
Q̇SR
Amount of heat recovered in [kW]
from the T.D.S. expander
Q̇SR = ૷S/V x (h''SR - cp x Tfw)
248/249
therefore:
૷)6([K
)6FS[7IZ ૷&21[FS[7IZ7&21૷DGGIZ[FS[7IZ7DGGIZ૷69[K
9FS[7IZ૷65[K
65FS[7IZ
and:
૷)6(
FS[>૷&21[7IZ7&21૷DGGIZ[[email protected]૷69[K
9FS[7IZ૷65[K
65FS[7IZ
K
)6FS[7IZ
with the individual calculation variables for:
Condensate return rate [kg/h]
„૷ CON
„TCON
Condensate temperature in [°C]
„Tfw
Feedwater temperature in
the deaerator as saturation
temperature as a function of
deaerator positive pressure
[see Tb 2]
„૷ ADD/FW Required additional amount of
feedwater (softened water) in
[kg/h] calculated from:
૷DGGIZ ૷)6[ $
૷&21
where
- ૷FS is the required total fresh steam
output and
- A - the required T.D.S. rate in [%]
„Tadd/fw Available temperature of additional
feedwater in [°C]
„૷ S/V Amount of exhaust vapour as an
amount of steam lost (deaerator outlet) in
[kg/h] calculated from:
૷69 Ł90[
>
૷)6[
$
@
where
ŁV/M is a factor for determining the
minimum amount of exhaust vapour
(see chapter D.7.3), dimensionless [-];
≈ 0.005 to 0.01
„h''S/E, h'' V Expansion steam and exhaust
vapour steam enthalpy each as function
of the deaerator positive pressure (pE/D)
according to [Tb 2]
„૷ S/R Amount of expansion steam from the
T.D.S. expander in [kg/h] calculated from:
D.10 Internal system demand
૷65 ૷)6[$[K
$(FS[7IZ
K
'65FS[7IZ
where h'A/E is the enthalpy of T.D.S. lye at
saturated steam temperature (Ts) as a
function of steam operating pressure (pB)
from [Tb 2]; (see also chapter D.7.2) and
„h''F/S Available fresh steam enthalpy of the
heating steam
Sample calculation 1
With assumed values for:
Fresh steam output
૷FS
= 12,000 kg/h
Fresh steam pressure
pB
= 13 bar
Saturated steam temperature Ts
= 195 °C
(from [Tb 2])
Enthalpy of T.D.S. lye
=f(pB) - h‘A/E
≈ 0.230 kWh/kg
Feedwater temperature
Tfw
≈ 105 °C
=Ł(Tfw) - pE/D
≈ 0.25 bar
Deaerator positive
pressure
Expansion steam and
= Ł (pE/D)
exhaust vapour enthalpy
=h''D/R ≈ h''EV
≈ 0.7457 kWh/ kg
Enthalpy of fresh steam
f(pB) h''FS
≈ 0.7743 kWh/kg
temperature
Tadd/fw
≈ 15 °C
Condensate flow rate
૷CON
= 6000 kg/h
Additional feedwater
Condensate temperature TCON
= 85 °C
T.D.S. rate
A
= 5 %
ŁV/m
≈ 0.0075 [-]
Factor for minimum
exhaust vapour output
250/251
૷DGGIZ ૷)6[
NJK[
>
૷69 Ł90[
[
૷'( ૷65 >
૷)6[
$
NJK[
૷&21
NJK NJK
$
@
@
NJK
૷)6[$[K
$(FS[7IZ
K
65FS[7IZ
[[N:KNJ[[
[[
NJK
and the resulting amount of heating steam
(૷FS/E) as the necessary internal steam demand
for the selected sample calculation:
૷)6(
૷)6(
FS[>૷&21y7IZ7&21૷DGGIZ[[email protected]૷69[K
9FS[7IZ૷65[K
65FS[7IZ
K
)6FS[7IZ
[>[[[[[[[[
૷FS/E ≈ 1269 kg/h ฬ 10.6 % of ૷FS
Note
Where ૷CON =0 (no condensate return) the
necessary amount of heating steam in the
sample calculation increases to
૷FS/E = 2018 kg/h ฬ 16.8% of ૷FS.
[[
System with 2 Vitomax 200-HS,
each with an output of 10 t/h, 16 bar
with regulated steam superheaters
and downstream flue gas heat
exchangers.
Klaipeda (Lithuania), district
heating plant, Klaipedos energija,
construction year 2007.
252/253
E Requirements and regulations
The following chapter addresses relevant requirements and regulations.
We refer here explicitly to land-based steam
boilers. The boiler installation conditions,
together with general requirements for the
system, the installation room and the building
are explained here in detail.
Furthermore, we refer to noise emissions,
transportation, handling and the basic
principles of earthquake protection.
253
E Requirements and regulations
254
Basic requirements and regulations
for the licensing procedure
254
E.1.1
265
268
E.1.2
E.1.3
271
E.1.4
272
Principle requirements and regulations
for the installation of steam boilers
273
273
274
277
278
279
E.2.1 Installation of category IV land-based steam boilers
E.2.2 Installation of category III land-based steam boilers (TRD 802)
E.2.3 Steam boiler system installation room
E.2.4 Acoustic emissions
E.2.5 Transportation and handling
E.2.6 Earthquake protection
Licensing procedure according to Section 13 of the [German]
Health & Safety at Work Act
Overview of German licensing procedures
Overviews and summary of application documents and
their compilation
Overviews for compiling the application documents
E.1 Requirements and regulations
Basic requirements and regulations for the
licensing procedure
E.1.1
Licensing procedure according
to Section 13 of the [German]
Health & Safety at Work Act
E.1.1.1. General information
Depending on the size and/or capacity (and
therefore the potential risk), the [German]
Health and Safety at Work Act (BetrSichVa))
specifies a reservation of permission for
some of the systems subject to mandatory
monitoring referred to in paragraph 1 section 2
of the BetrSichV. The system types covered by
the reservation of permission are subsequently
listed in paragraph 13 section 1 Items 1 to 4 of
the BetrSichV.
Assembly, installation, operation, significant
modifications and changes to the design or
operating mode that affect the safety of the
system require permission. The reservation of
permission therefore applies to both new and
existing systems.
A system in the sense of the regulation is
composed of several function units that
interact with one another, the safe operation
thereof being largely determined by
these interactions.
Facilities required for safe operation of the
system subject to mandatory monitoring are
also covered.
Hence the whole system must be considered
in the licensing process, i.e. not only the part
of the system that determines the purpose of
the system, for example the pressure vessel
of a steam boiler system, but all parts, devices
and equipment that have an effect on the safe
operation of the system.
a)
Regulations concerning health and
safety protection in the provision of
equipment and its use in the work
environment, concerning safety in
the operation of systems requiring
supervision and those concerning
organisation of operational industrial
safety ([German] Health & Safety
at Work Act – BetrSichV) dated
27 September 2002 (Federal Law
Gazette BGBl. I p. 3777; 25/11/2003
p. 2304; 6/1/2004 p.2; 23/11/2004
p.3758; 25/6/2005 p.1866).
A whole system can also consist of several
(sub-)systems, i.e. an actual system can be
a system subject to mandatory monitoring
both in terms of the pressure risk and risk of
explosion or in respect of the risk associated
with the storage and filling of inflammable or
highly flammable liquids.
A significant change according to paragraph 2
section 6 of the BetrSichV to a system subject
to mandatory monitoring is characterised by
the system being modified to the extent that
it represents a new system in terms of safety
features. In the case of a significant change,
the whole system must be considered in
the licensing process in the same way as
new systems.
If a modification (BetrSichV paragraph 2
section 5) to the design or operating mode
is carried out that affects the safety of the
system, the licensing procedure only extents
to the modified part. However, it must be
ensured that the safety of the whole system
is still guaranteed.
Assembly and installation encompasses all
activities required to prepare the system
on site for the commissioning process.
This also includes testing prior to initial
commissioning. Operation of a system subject
to mandatory monitoring also includes testing
by third parties.
Steam boiler systems
„are fired or otherwise heated pressure
vessels at risk of overheating for the
generation of steam or heated water with
a temperature greater than 110°C that,
according to Article 9 in conjunction with
Appendix II Diagram 5 of EU Directive
97/23/EC, must be be classified as
Category IV
Exceptions are systems in which steam or
heated water arise in a manufacturing process
by means of heat recovery, except where flue
gases are cooled and the steam or heated
water produced is not fed predominantly into
the processing plant (process-related waste
heat boiler). For the purposes of the licensing
requirement, it is irrelevant whether the
pressure vessel has been brought into service
as a single component or as an assembly
according to the Pressure Equipment Directive.
The permit covers the whole steam boiler
system. Apart from the steam boiler itself, the
steam boiler system includes the following
parts and equipment, if available:
„Boiler supporting structure, thermal
insulation and/or refractory lining and casing
„Combustion equipment
254/255
„Steam and heated water pipes and their
valves serving the purpose of steam boiler
operation, insofar as they form a functional
unit in conjunction with the steam boiler,
up to the interfaces defined in the risk
analysis/safety evaluation
„Facilities within the boiler room for
storage, preparation and supply of fuels,
as well as facilities outside the boiler room
for the storage, preparation and supply of
highly flammable and all powdered, liquid
and gaseous fuels
„Facilities for the provision of air to the
steam boiler, including the fan and the air
preheater heated with flue gas
„Superheaters and intermediate
superheaters heated with flue gas and
fitted with shut-off devices, as well as the
steam cooler and associated connection
lines located in the boiler room
„Feedwater preheater fitted with shutoff devices, insofar as it is located in the
combustion flue gas flow, as well as the
feed equipment and the feed lines leading
to the steam boiler
„Facilities for discharging flue gas, including
the induced draught systems, the chimney
and/or the flue gas line routed via a cooling
tower, as well as the systems built into the
flue gas discharge equipment for reducing
air contamination
„Facilities for pressure maintenance and
volume compensation (pressure expansion
vessels, expansion tanks) in heated water
generation systems, including associated
connection lines
„All other facilities that serve the purpose of
steam boiler system operation
„Equipment in which the generated steam
is superheated or cooled and which is
located wholly or partially within a steam
boiler, where steam boilers are defined
as an arrangement of vessels or pipes
that are subject to a pressure higher than
atmospheric pressure
„All steam boiler monitoring and safety
equipment
„Boiler installation room
E.1.1.2
Requirements for the
application documents
1.—Standard requirements
All documents required for assessing the
system must be enclosed with the application.
If any relevant specifications are omitted,
additional demands from the authorities or
the approved monitoring body (ZÜS) may lead
to delays in the licensing process. Application
documents that are incomplete and/or
expert opinions that do not comply with the
accreditation conditions of the ZÜS shall be
returned to the applicant.
Systems subject to mandatory monitoring in
the sense of the BetrSichV are mainly systems
subject to EU directives offered for sale or
systems that at least contain components
to which these regulations apply. See also
[German] Equipment and Product Safety Act
(GPSG) section 1, paragraph 2(7).
The certificate of conformity, however,
needs not have been issued until directly
before commissioning and does not
constitute a mandatory element of the
application documents. The scope of
application documentation to be submitted
differs depending on whether a certificate
of conformity has already been issued for
the complete system or only the general
conditions are known.
If only system components and not the whole
system have been subjected to a conformity
assessment procedure, the compatibility of
the individual components with each other
must be described in the application.
The actual manufacturer of the system need
not yet be specified in the application. In this
case, however, the system must be described
in detail with reference to the design data (e.g.
output, fuel, operating mode and construction),
so that the system can be assessed in
respect of safe operation. Requirements that
have already been tested in the conformity
assessment procedure need not be tested
again as part of the licensing process.
E.1 Requirements and regulations
Insofar as compliance with quality
requirements is verified by certificates of
conformity issued to the initial vendor, the
licensing procedure focuses on correct siting
and safe operation of the system. For example:
„The precise location of installation either in
the open air or in a building
„Potential risks to the system (collision
protection, fire protection etc.) and
the respective precautions, taking into
consideration the requirements that the
manufacturer makes of the installation site
in the operating instructions as a result of
the risk analysis
„Translation of the manufacturer's
specifications to the actual local
conditions, for example on the
"Ex zone" plan
„Mode of operation, for example, the
special safety and organisational
precautions to be taken in the case of
intermittent supervision
„Verification of compatibility of the
individual components with each other,
in the event that no proof of conformity is
provided for the whole system
The application must include all the information
that the ZÜS requires for the expert opinion
and/or the test before commissioning (see
sections 4 and 6).
Attention must also be paid to the fact that
the expert opinion of the ZÜS is a formal part
of the application (BetrSichV paragraph 13
section 2 BetrSichV). With acceptance of the
expert opinion as an application document,
any applicable deficiencies, supplementary
requirements and proposed measures
described in the document automatically
become an integral part of the application. The
necessary coordination process between the
applicant and the ZÜS is described in greater
detail in section C.14.2.4.
As a rule, the subsequent system operator
and the applicant are one and the same. If the
application is submitted by a third party, such
as an engineering consultancy as a service
for the subsequent system operator, then the
appropriate authorisations must be enclosed
with the application.
Insofar as the applicant, by way of exception,
is not the subsequent system operator, it
must be ensured that the operator satisfies
all the requirements detailed in the licence.
If application documents are returned to the
applicant for the purpose of completion, this
does not constitute a formal decision; the
process is solely interrupted, whereby no
administration costs are charged.
2. Submission of an explosion
protectionconcept
If the required risk analysis in accordance
with the [German] Hazardous Substances
Ordinance (GefahrstoffV), taking account
of Appendix III Item 1, establishes that the
occurrence of a hazardous substance of an
explosive amount in the atmosphere cannot be
avoided in the system applied for, then a check
must be carried out in the licensing procedure
as to whether the necessary structural
fire protection and structural conditions
for explosion protection exist, even if the
explosion protection document required by the
BetrSichV need only be prepared by the time
of commissioning.
The term "explosion protection concept"
has established itself for the concept to be
presented in the application. The statements
required in the explosion protection concept
are listed in the Appendix.
3.—Documents required
The documents required for each individual
system type are to be found in the checklist
in the Appendix. Depending on the case
in question, additional documentation may
be necessary.
256/257
E.1.1.3. Requirements for the expert
opinion from an approved
monitoring body (ZÜS)
With reference to siting and safe operation,
the expert opinion forms the fundamental
basis for the licensing procedure. It must
therefore be resilient.
According to the regulatory text, it must be
evident from the expert opinion that
„siting
„design and
„operating mode of the system
comply with the regulation.
The information that the expert opinion from
the approved monitoring body must contain
as a minimum requirement according to
AKK-RL [3] is reproduced in the Appendix.
Furthermore, the official justification of
the BetrSichV states that: "Before issuing
a licence, the expertise of a ZÜS must be
called upon and this shall check whether
the interaction between parts of the system
under actual operational conditions allows safe
operation of the system."
When preparing an application, a differentiation
must be made between three case situations:
„Case 1: A declaration of conformity is
available for the whole system
„Case 2: There are some subsections with
a declaration of conformity and some
without, but all components are subject to
harmonised regulations
„Case 3: (Sub)sections do not fall within the
harmonised regime (such as storage tanks
in the case of flammable liquids)
Depending on the case in question, the
ZÜS test scope in the expert opinion differs
from that applicable to testing before
commissioning. Everything that is not verified
on the part of the manufacturer must be
proven during testing, at the latest prior
to commissioning.
If, in the case of pressure equipment,
an assembly is assembled under the
responsibility of the operator, a certificate
of conformity must be available for each
individual piece of pressure equipment at the
time of the acceptance test. The ZÜS checks
the correct selection and installation of the
individual pressure devices during testing at
the latest prior to commissioning.
It must be evident from the ZÜS expert
opinion that all of the following issues
have been checked – insofar as no relevant
measures have been proposed – and complied
with:
„Completeness of information with
reference to safety issues, also including,
for example:
„Statements regarding the intended
materials to be used and
„Specifications concerning special safety
measures for employees and third parties.
„Requirements with reference to the
installation site (taking account of
neighbouring plots of land), including
checking of:
„Compliance with the necessary distances
to neighbouring systems due to potential
reciprocal risk, particularly in the event of
a fire
„Compliance with the installation
requirements regarding explosion
protection, i.e. particularly in terms
of checking the "explosion protection
concept" insofar as safety zones are
required for explosion protection
according to Appendix 3 of the BetrSichV,
and compliance with the structural
requirements (e.g. no openings in walls or
floor drains in the safety zones)
„Guarantee of the necessary protection
from damage depending on the situation
at the installation location, with particular
reference to vehicular traffic taking
account of the vehicle type and the
speeds travelled
„Exclusion of any other potential reciprocal
effects with regard to neighbouring
systems, such as the risk of undergrate
firing due to leaking flammable liquids or
fuel oil/diesel
„Suitability of the system and/or system
components for the intended operating
modes and for the intended form
of supervision
Insofar as the whole system is not subject
to only one conformity assessment
procedure, a check should be conducted
at this stage regarding the suitability and
mutual compatibility of the individual
intended components.
The following statement is necessary as the
result of a positive expert opinion:
Note
A statement such as
"there are no concerns
preventing conferral
of a licence" does not
comply with BetrSichV
specifications and is
therefore insufficient.
E.1 Requirements and regulations
Inspection of the application documentation
by ...… has established that the siting,
design and operating mode of the …..system
complies with the requirements of the
BetrSichV, provided that the following
measures are implemented together with the
specifications in the application: ...
The intended project therefore complies
with the requirements of the [German]
Health & Safety at Work Act (BetrSichV).
The following aspects must be considered in
drafting the expert opinion:
The ZÜS must firstly pay particular attention to
maintaining its necessary independence as an
adjudicator, which implies that its advisory role
is subject to very strict limitations. This is dealt
with and defined in detail in [1] and [2], also
with regard to auditing activities.
„In drafting the expert opinion, the ZÜS
must not have a formative influence on
the concept, i.e. it must not act in the
same way as an engineering consultancy;
rather, it should specify as precisely as
possible which target requirements of the
BetrSichV and the technical regulations
are taken into account inadequately.
If important points are not taken into
account, the ZÜS must firstly prompt
the applicant to provide supplementary
information prior to publishing its opinion.
Only afterwards can the ZÜS check
whether the measures taken are adequate
and comply, for example, with the
technical regulations of the BetrSichV. If
there are several alternatives for achieving
a particular safety-related objective (e.g.
with reference to the design of adequate
collision protection), the ZÜS need only
assess whether the solution proposed by
the applicant is sufficient. At the same
time, the applicant can propose several
solutions and then decide at a later stage
which of the solutions is implemented
„No demands may be made of the quality
of the system or system components,
insofar as these have been subjected to
a conformity assessment procedure; the
quality is assessed subsequently by an
approved body
„The ZÜS shall list each of the submitted
application documents that it has audited
(see [4]). Stamping of the application
documents by the inspector as in the past
is no longer necessary
„Insofar as requirements are still
outstanding, the ZÜS must stipulate
them in concrete form with specification
of the reason, but without undertaking
any planning activity. Repetition of
texts from technical regulations is not
sufficient. Rather, it must be specified
how the regulatory requirement is actually
to be applied to the assessed system.
For example: "The discharge pipe must
be routed 3 m above the roof of the
neighbouring warehouse."
„A long list of requirements in the form
of pre-formulated texts tailored to the
specific system type that practically repeat
the application specifications make the
inspection appear at least very superficial
„Legal obligations may at most be included
as notes in the expert opinion, but not as
proposals for any incidental provisions
„A description of the approach taken during
the inspection or explicit reference to the
information in the application that has
been audited is possible, but this must
be clearly separated from the additional
requirements made
„On principle, information provided in the
application must be checked on site by
the ZÜS in accordance with [3]. The ZÜS
must assess beyond any doubt whether
the installation location is suitable. A site
inspection is therefore an inherent part of
the expert opinion
„In the expert opinion, the ZÜS must cover
all the risk areas touched on by the system.
If it is unable to do so comprehensively,
for example due to the limited extent of its
approval, this must be pointed out to the
applicant explicitly. In this case, another
ZÜS may need to be called upon, whereby
one of the approval bodies must play the
coordinating role so that the intersections
between both aspects (e.g. pressure
hazards and explosion protection) can also
be considered
258/259
„If special requirements are made of the
equipment in individual cases (such as the
extension of a discharge pipe), this must
be substantiated, for example with the
circumstances at the installation location
(which must be described)
1. General information
The application must be submitted in triplicate
with the required documentation, including
the expert opinion from the approved
monitoring body (if necessary) to the regional
administration. Only if planning permission is
to be granted at the same time, do the extra
copies required for the planning permission
process also need to be enclosed. If possible,
preliminary discussions should be held with
the applicant to clarify which documents
are necessary.
If the documentation is complete, the
applicant receives an acknowledgement of
receipt from the authorities.
The 3-month deadline is calculated from the
date of receipt of the complete application
documentation.
If the check for completeness reveals that
documents essential for evaluating the
application are missing, the applicant is
requested to (re)submit these documents
with a note that the 3-month period has not
yet started.
The period only begins on receipt of all
(additionally) required documents. The
applicant also receives an acknowledgement of
receipt for the additional documents.
If applicants intend to implement a large
project in several stages and each application
only covers a part of the whole system, then
the respective licence must be restricted
to the assembly and installation of that part
of the system applied for. In this case, the
licence for operation of the whole system
can only be combined with the licence for
assembly and installation of the final part of
the overall system.
2. Scope and depth of auditing by the —
licensing authority
The licensing authority is not assigned
the role of "chief adjudicator", i.e. it can
particularly depend on the fact that the ZÜS
– insofar as an expert opinion is included in
the application – has audited the application
documentation thoroughly and competently.
However, the licensing authority must still
check the application for completeness
and plausibility. Knowledge specific to the
technology in question must also be available
for this purpose.
Lack of due diligence by the applicant and/or
the ZÜS is evident in particular from the fact
that
„Information is inconsistent
„Information on the installation location is
missing or imprecise
„The ZÜS proposes unspecific measures
„Potential risks (fire loads, mechanical
hazards due to vehicles) are inadequately
described and evaluated
„It remains unsettled how the deficiencies
indicated in the expert opinion from the
ZÜS are to be rectified
If the licensing authority has any enquiries
regarding the form or content of the expert
opinion or the ZÜS, for example, has proposed
any measures that are incompatible with
the information in the application, then the
licensing authority turns firstly to the applicant.
With the consent of the applicant, individual
issues can then also be clarified directly
between the licensing authority and the ZÜS.
If the issues can be clarified amicably and
unequivocally, the final version selected must
arise unambiguously and in concrete terms
from the licence and/or from the accepted
incidental provisions.
Should applicants decide on another solution
for achieving the intended objective after
approval has been granted, then they can apply
informally at any time for replacement of the
means, i.e. for an amendment to an incidental
provision. If this is taken into account, the
letter of confirmation of the licence should
be reattached. A formal change permit is not
necessary for a modification to requirements.
E.1 Requirements and regulations
If differences still exist following discussion
thereof, with reference to statements in the
application and/or the expert opinion, then the
application shall be returned to the applicant
with a relevant explanation and a request for
supplementary information and/or clarification.
A separate consultation with the applicant
is not necessary prior to issuing a decision
if the application has been accepted in its
entirety. Otherwise a consultation must take
place. If applicants do not agree with any of
the incidental provisions, they can apply for
replacement of the means. If the solution
is acceptable, this is confirmed in a letter to
which the licence is attached.
3. Involvement of other agencies
The licensing procedure is established as
a lean process and does not display any
bundling effects. It deals solely with the safety
issues relevant to the system on the basis of
the BetrSichV.
In North Rhine-Westphalia, however, there is a
special situation that includes the licence with
the building permit according to paragraph
63 of the [NRW] Building Regulations (BauO).
Outwardly, therefore, only one licensing
authority makes an appearance; the one that
issues the licence and planning permission
in one legal document. Hence, the overall
decision includes the intrinsically independent
part of the building permit. This is also
expressed within the administrative decision
by means of a clear delimitation.
Regarding the involvement of other agencies,
a differentiation can be made between
two cases:
1) No other legal sectors (such as building,
planning, water or environmental law)
are involved with the modification or
construction of a system; in other words, it
only has to do with technological questions
and matters of system safety. In this case,
the licensing authority issues the licence
without the involvement of other agencies.
2) Inspection of the application on the basis of
BauO paragraph 63ff reveals that a building
permit is required. The requirement for
planning permission can be justified by
the system exceeding a particular order of
magnitude (e.g. in the storage of gases as
part of a filling system, if the storage tank
has a volume > 5 m³). It can, however, also
be founded on planning permission solely
being required due to the change in usage
of the property. If it cannot be established
without doubt whether or not planning
permission is required, then the planning
authority must be involved. If the BauOA
(planning department) confirms the need
for a building permit, this decision is binding
for the licensing authority. In this case, the
applicant must also include documents
required for inspection by the BauOA with
the application.
The responsible planning department is
requested to deliver a judgement within a
specified period (normally 4 weeks) from
submission of the necessary documentation.
Other public legal issues that could be
affected by erection and operation (i.e.
subsequent use of the system), must be
checked during the course of the planning
application process. Whether and to what
extent this is the case is the responsibility of
the BauOA. Within the scope of its auditing
obligation, the BauOA must also check for
compliance with emission control legislation.
The licensing authority is not obliged to
involve any other agencies directly.
The wording and incidental provisions of
the licence and building permit should be
specified separately. In the licence section,
only incidental provisions concerning
technical requirements (design, equipment
or operation) are permissible. The proposed
incidental provisions from the BauOA
cannot be embodied in what is the direct
responsibility of the licensing authority;
they can only be included in the section
of the administrative decision relating to
building regulations.
260/261
According to building law, it is perfectly
permissible to restrict the use of a building
or a system permanently, especially by
limiting the operating times (e.g. to daytime),
if this appears to be called for in light of the
designation of the property (e.g. as a mixed
use area).
The licensing authority does not check the
incidental provisions deemed necessary
by the BauOA for the section of the
administrative decision dealing with building
legislation. In the case of obvious serious
errors, feedback should be provided to
the BauOA.
Should it prove necessary in exceptional
circumstances to directly involve other
agencies for the purpose of speeding up the
process, the submissions must be returned
via the planning department, because it is the
only body capable of checking the admissibility
and correctness of the incidental provisions
proposed by them. The proposed incidental
provisions cannot be embodied in what is the
direct responsibility of the licensing authority;
they can only be included in the section
of the administrative decision relating to
building regulations.
If it is established during the course of the
process that a statutory requirement from
another legal area has been omitted, the
process is suspended until the requirements
with respect to the applicant have been
fulfilled. For this purpose, the applicant is
notified of the circumstances and referred
to the fact that the process will only be
resumed once the procedural requirements
have been satisfied. The three-month deadline
is extended accordingly. One such legal
requirement is to be found, for example, in
paragraph 25 section 1 of the [NRW] Highways
and Bye-ways Act.
The licensing authority checks the issues of
occupational and operational safety. Incidental
provisions are formulated as necessary.
The incoming statements and expert opinions
are examined to see whether they relate
to requirements specific to the building or
the system technology. Proposed incidental
provisions that represent pure reproductions of
legal texts must not be adopted.
An extension of the 3-month deadline is only
possible in justifiable circumstances. This could
be the case if the BauOA requests additional
documents. The applicant is notified in writing
that the deadline is being extended by an
appropriate period.
If inspection of the documents yields that
the system is not licensable, a negative
administrative decision is issued. Assembly
and installation of the system must be
explicitly prohibited in that decision. In the
case of a request for change, if applicable, the
non-licensable amendment must be prohibited.
The operator and, if applicable, the
BauOA each receive one copy of the
licensing decision.
4. Consequences of issuing the license
and planning permission in one
decision
If problems are to be expected due to
inclusion of the building permit, for example
with reference to admissibility of use of the
property in the planned form, several options
are available:
„The applicant can be requested to present
certain requirements in the application
itself, for example a restriction of the
operating times. Then the permit can be
granted without restrictions
„The applicant is requested to have the
other statutory issues affected by a
building permit examined in a preceding
process. In this way, the admissibility of
a change in use or an access road from
a public highway (see paragraph 9 of the
[German] Federal Trunk Road Act) can be
examined and decided upon in advance
„If the future use of the system at the
intended location is clearly not at all
permissible (for example in the outdoor
area) for other statutory reasons, then the
application can also be declined with the
substantiation that no decision-making
interest exists. The applicant is at liberty to
appeal against such a decision
E.1 Requirements and regulations
In general, other statutory issues must not
be based on the BetrSichV; rather, only on
building law, for which the BauOA bears
sole responsibility.
5. Licence within a BImSch process
If a system requiring a licence is part of a
system subject to authorisation according
to the German Immissions Act (BImSchG),
then the licensing authority is not responsible
for the licence; rather, the office managing
the BImSch process. Process regulations
according to the BImSchG and the 9th German
Immissions Ordinance (BImSchV) are relevant
here. The 3-month deadline does not apply. It
is the time limit set by the office managing the
BImSch process that has to be complied with.
The requirements for documents that need
to be submitted in the licensing procedure
according to the BetrSichV also apply to
documents within the scope of the BImSch
process (including the expert opinion from
the ZÜS). Following inspection of the
documentation, a statement is made to the
responsible approval agency, if necessary, with
proposals for incidental provisions.
E.1.1.4
Inspection before commissioning
The extent of inspections (and therefore also
the one before commissioning) is specified in
paragraph 15 section 2 of the BetrSichV. The
inspection certificate required in accordance
with paragraph 19 section 1 of the BetrSichV
must include a minimum of the following
information according to AKK-RL [3]:
„Legal basis
„Initial inspection, inspection following
modification, following a major change or
after corrective maintenance according to
paragraph 14, BetrSichV
„Recurring inspection according to
paragraph 15, BetrSichV
„Extraordinary inspection according to
paragraph 16, BetrSichV and specification,
if applicable, of whether a whole system or
a partial system has been inspected
„Master data of the office (name, postal
address, identification as an approved
monitoring body)
„Operator data (name, postal address)
„Specification of the maintenance
contractor (if necessary)
„System location (system identification,
in-house designation and system ID,
plus, if necessary, precise description of
the system interfaces, for example with
slide gate number, pipe number and/or
specification that it is a partial system)
„Inspection date and inspection period,
if applicable
„Clear indication of the relevant inspector
„Signature of the inspector
„Unique identification of the
inspection certificate
„Inspection result, if applicable with
information on defects
„Release for commissioning or
continued operation
„Inspection interval
In addition to the scope of inspection
before commissioning and the relevant
documentation, the following is expected of
the ZÜS inspector:
„Inspection of the whole system, including
siting and required safety clearances
262/263
„Insofar as the system has only been
certified in parts, the supplementary
statement that the components and
assemblies used are compatible with
each other and that the required reciprocal
safety equipment is available and its
integration complies with the state of
technology (quality)
„Explicit confirmation that the requirements
relating to assembly, siting and operation
have been complied with in accordance
with the state of technology (operation)
„Confirmation that the specifications in the
licence application have been complied
with, including the expert opinion from the
ZÜS and any applicable special incidental
provisions in the licensing decision
„Reference to the inspection certificate
from the qualified person concerning
testing for explosion protection before
commissioning (if necessary), insofar as
explosion protection is not checked by the
ZÜS itself
A positive inspection certificate includes the
following inspection contents, even if they are
not dealt with explicitly in the certificate:
„The statement that the supervision
method (including possible indirect
supervision) complies with information in
the application and whether any applicable
alternative measures for supervision have
been taken
„The statement that the selected protection
against possible mechanical effects
is adequately sized to meet the actual
installation conditions, insofar as no
relevant precise specifications were made
in the application
„The statement that the selected measures
for preventing access by unauthorised
personnel are sufficient (enclosure etc.)
„The statement that the necessary
clearance with respect to potential
fire hazards and any other hazards
has been complied with, particularly
with respect to the risk of undergrate
combustion, for example, installation at
a sufficient distance from a petrol station
where a liquid gas storage tank is sited
above ground
„The fundamental statement that the
necessary documents, for example the
explosion protection document and
a system-specific "Ex-zone" plan, are
available to employees, along with the
operating instructions
In the system-specific technical regulations
that are still largely based on former individual
pieces of [German] legislation (DruckBehV,
DampfKV, VbF, AcetV) and hence can only be
applied to a limited extent, further specific
aspects of the inspections are addressed,
which must be observed.
The evaluation of identified deficiencies is
absolutely essential, i.e. an unequivocal
statement regarding the admissibility
of commissioning, specifying any
applicable restrictions.
In any event, the ZÜS must always issue
a certificate regarding the result of the
inspection without delay and hand this over
to the operator, so that an indication of the
permissibility of operation is available on-site
at the operating location. This must take
place within one week. On no account is it
permissible for the ZÜS to issue a satisfactory
inspection certificate weeks or even months
later, after the operator has corrected all the
faults identified during the inspection and
explained during the meeting.
Missing pieces of evidence must be noted
as defects in the inspection certificate and
qualified accordingly (minor, hazardous,
serious). Resulting consequences must also
be specified.
Implementation of the system begins with the
licence application. Hence, the state of the art
at this time applies. Should new, completely
up-to-date findings be made during the course
of the licensing process, the licensing authority
can impose supplementary requirements in
the licensing decision. The ZÜS is bound to the
application documents and the requirements
in the licensing decision during the inspection
before commissioning.
E.1 Requirements and regulations
If the state of the art has made advances
in the period between issuance of the
administrative decision and performance of
the inspection prior to commissioning and
the ZÜS therefore establishes during the
inspection and prior to commissioning that
variance exists with respect to the state of the
art, the ZÜS can report this to the monitoring
and/or licensing authorities, who themselves
must then check whether supplementary
requirements need to be applied in accordance
with paragraph 13 section 5 Clause 2 of the
BetrSichV. The ZÜS may not declare deficits
due to advances in the state of the art
as defects.
Insofar as the operator has already determined
the necessary inspection intervals at the time
of the inspection, the ZÜS can carry out the
necessary examination of the determined
interval, according to BetrSichV paragraph 15
section 4, in conjunction with the acceptance
test. In so doing, a differentiation must be
made between the individual components and
between the various hazardous features of
the system.
If the ZÜS has already recommended an
inspection interval in the expert opinion,
the operator can use this information in
its safety assessment for determining the
inspection interval. In principle, the ZÜS
only states anything after the operator's
safety assessment, which is normally only
practical following the inspection prior
to commissioning.
In the case of recurring inspections, the ZÜS
need not explicitly confirm the inspection
interval defined initially. However, if the
monitoring body has any indication that the
interval should be reduced, then it reports this
to the operator. The operator itself must then
undertake another safety assessment, which
is subject to examination by the ZÜS.
264/265
Fig. C.14.3–1
E.1.2
Reservation of permission
Overview of German licensing
procedures
The necessary licensing procedure or approval
process can exhibit differences from one
federal state to another. Before initiating the
licensing or application process, it is therefore
always advisable to coordinate [steps] in
advance on an individual basis with the local
approval agency, at the same time presenting
the boiler system to be approved.
Overviews of the standard licensing procedure
according to BImSchG (BImSchV 1/4/13, state:
Berlin/Brandenburg, see also Fig. C.14.3-2
and C.14.3-3)
E.1 Requirements and regulations
Fig. E.1.2-1
Overview of licensing procedures
Steam boiler system
to BImSchG
(1st German Immissions Order)
[see also appendix A4]
Application to permit
granting authority
(for example competent
commerce authority)
Details to
planning authority
Details to
environment
authority
Asking for
comments
Permit-granting
authority grants permit
System is installed
Expert checks
system
System may be
operated
Final acceptance
by the authority
=> system not subject to permits according to the
Federal Immissions Act (BImSchG) [Germany]
Overview of the standard sequence of events in the licensing procedure according to BImschG (State of Berlin)
Source: TÜV Rheinland
266/267
Fig. E.1.2-2
Overview of licensing procedures
Steam boiler system
to BImSchG (4th/13th
German Immissions Order)
[see also appendix A4]
Expert statement
Application to
environment authority
Details to
environment
authority
Details to
planning authority
- Publication of
intended project
- Public participation
Documents to permit-granting authority
(for example competent commerce authority)
Environment authority
grants permit
Other authorities
- Aviation
- Federation
- etc.
System is installed
Expert checks
system
System may be operated
Final acceptance
by the authority
=> system subject to permits according to the
Federal Immissions Act (BImSchG) [Germany]
Overview of the standard sequence of events in the licensing procedure according to BImschG (State of Berlin)
Source: TÜV Rheinland
E.1 Requirements and regulations
E.1.3
Overviews and summary of
application documents and
their compilation
Checklist for the compilation of application
documents for the approval process
according to the German Immissions Act
(source: Federal Environmental Agency,
Krefeld, 08/2005)
General preamble:
The following brief checklist should provide
applicants with assistance in preparing
application documentation for approval
processes in accordance with the German
Immissions Act. Documents and information
are specified in this checklist, which must
normally be submitted.
Depending on actual specifications, it can
however arise that the submission of certain
documents can be dispensed with or that
additional documents are indispensable for
an audit. In cases of doubt, it is therefore
recommended that contact be established
with the approval agency in order to discuss
the finer details.
The following general requirements must
be observed:
„Document formats and document folding
must comply with DIN regulations
(particularly DIN 28004). Each additional
copy of the application must be bound in
a separate file. As a rule, 6 copies of the
application must be submitted for carrying
out official tasks
„All application documents must be
signed by the applicant or an authorised
representative, with the design
documentation also being signed by the
system architect and the expert opinion by
the expert involved
„The application and the table of contents
must be signed on all events by the
applicant or an authorised representative
„Trade secrets must be indicated
and the corresponding documents
submitted separately
268/269
a)
Checklist for steam boiler systems
Name or company name and address of the operator
Name or company name and address of the manufacturer (if known)
Intended operating location and address (except for mobile steam boilers)
Description of the steam boiler system and the intended operating mode, including schematic
drawings that reveal the design, dimensions and mounting of the
relevant safety equipment
For the system components that must be brought into service according to an EU directive, details of the corresponding
conformity assessment procedures (Machinery Directive 98/37/EC; Pressure Equipment Directive 97/23/EC;
ATEX 94/9/EC for operating equipment, insofar as hazardous explosive atmospheres can form),
declaration of conformity for the assembly (including a list of components to which it applies) or, if conformity
assessment procedures have not yet been carried out, specification of the category from which devices are selected
and a description of the interfaces
Drawings (layout and section, escape routes, pressure relief areas)
„
Boiler installation room
„
Facilities for the storage of fuels
„
Facilities for discharging flue gases, including chimney
(plus the associated structural calculations and height calculation)
Site plan containing the following information:
„
Location of the installation room
„
N eighbouring areas on the property and their intended purpose
„
Adjacent plots of land, buildings, thoroughfares and spaces
Information on building design
„
Ventilation facilities
„
Escape routes
„
Structural fire protection
Expert opinion from an approved monitoring body from which it is evident that siting, design and operating mode of the
systems comply with the requirements of the Act
Specification of total costs including VAT
Special procedures and deviations from the technical regulations must be described separately.
Design documents for pressure equipment and assemblies according to the Pressure Equipment
Directive need not be enclosed. According to LASI (Committee of the States for Occupational Safety
and Health) guidelines for BetrSichV Section C.14.1, the old forms can still be used.
However, it must be noted that these need only be partially completed and that additional information
is required.
E.1 Requirements and regulations
b)
Checklist for the expert opinion
In accordance with AKKRL [3], the expert opinion from the approved monitoring body must contain at
least the following information:
Legal basis (e.g. paragraph 13 section 2 BetrSichV)
Reason for the expert opinion
Master data of the office (name, postal address,
identification as an approved monitoring body)
Operator data (name, postal address)
System location (system identification, in-house designation and any system ID)
Description of the project with designation of the main components
Date report created, date of site inspection and scope of system inspected
Basis for testing
Test documents viewed
Unique identification for the expert opinion
Assessment of the system components and/or the system or systems
Result of the assessment with any applicable conditions and recommendations
Clear specification of the expert involved, signature of the expert
c)—Necessary statements in the explosion protection concept
In the case of areas at risk of explosion in enclosed spaces (rooms):
„Designation of the enclosed spaces
„Classification of enclosed spaces into zones according to BetrSichV Appendix 3
„The statement that electrical and other installations in the building comply with requirements
according to BetrSichV Appendix 4
„The statement that any applicable structural measures deemed necessary in accordance with
GefStoffV Appendix III No. 1 have been taken, for example prevention of fire transference
In the case of areas at risk of explosion in the open air:
„Classification of areas into zones according to BetrSichV Appendix 3
„The statement that the requirements for zones in the open air (such as the omission of openings to
lower lying areas) have been complied with
„A statement regarding the quality of any walls that enclose the open air areas
„The statement that electrical and other installations comply with requirements according to
BetrSichV Appendix 4
270/271
E.1.4
Overviews for compiling the application documents
Application documents
Boiler assembly
Number of application
Operator
Design
Viessmann2b)
engineer
documentsa)
III
IV
Steam boiler system description
3
3
X
X
Steam boiler system operating mode
3
3
X
X
Steam boiler system drawings
3
3
X
X
Boiler house floor plan
4
4
X
X
Layout of the fuel storage facility
4
4
X
Layout of the flue gas discharge equipment
4
4
X
Layout of the chimney
4
4
X
Sectional drawing of the boiler house
4
4
X
Sectional drawing of the fuel storage facility
4
4
X
Sectional drawing of the flue gas discharge equipment
4
4
X
Sectional drawing of the chimney
4
4
X
Static chimney calculations
3
3
X
4
4
X
4
4
X
Steam boiler system wiring diagrams
-
3
X2b)
Burner description/combustion system
3
3
X2b)
X
For drawings: scale 1:100; for site plans: scale 1:1000 to 1:5000
Site plan of the installation room
+ neighbouring rooms with intended purpose
Site plan of the adjacent plots of land, buildings,
thoroughfares and spaces
(Source: TÜV Rheinland, issue: 11/2007)
a)
Minimum scope that can be
submitted in agreement with the
authorities partially except for
6 (8) copies.
b)
Insofar as Viessmann is the supplier
of these system components.
E.2 Requirements and regulations
Note
Steam boiler group
assignment, see also
section C.14.
Principle requirements and regulations for the
installation of steam boilers
General requirements
Boiler systems should always be installed in
buildings that are free from the risk of frost,
dust and dripping water. The temperature in
the installation room should be between 5 and
40 °C. Provision must be made for adequate
ventilation (combustion air supply). In so
doing, attention must be paid to ensuring
that no corrosive elements (e.g. chlorine or
halogenated compounds) are drawn in with
the combustion air.
The floor must be level and offer sufficient
load-bearing capacity. For the load-bearing
capacity, the maximum operating weight,
i.e. the wet weight together with all
fitted components, must be taken into
consideration. Boilers can be installed
without special foundations. However,
foundations are advisable for better cleaning
of the installation room.
Regulations
DDA information, issue 2.2002 [Germany],
describes the "installation and operation of
land-based steam boiler systems with CE
designation". These rules are largely drawn
from TRD 403 or, depending on water capacity
and permissible operating pressure for easier
installation, from TRD 702.
Furthermore, the respective state building
regulations and combustion ordinance must
be observed.
Alongside minimum requirements for
clearances for operation and maintenance,
escape routes, flue gas routing, fuel storage
and electrical equipment, these regulations
stipulate the type of room where steam boilers
may be installed. High pressure steam boilers
(category IV according to TRD) must not be
installed in the following areas:
„in, below, above or next to living spaces,
„in, below or above social spaces
(e.g. washrooms, changing rooms and
rest areas) and working areas
The regulations also list less strict installation
conditions, depending on the product of water
content and permissible operating pressure,
taking into consideration the maximum steam
output. However, the regulations stipulate
different requirements, so specific clarification
in advance with the locally responsible
authorities is recommended.
The respective state building regulations
must be observed for the installation of
steam boilers. In general, siting of boilers
in working areas is not out of the question.
In principle, the requirements specified in
TRD 403 (Group IV Steam Boilers) and
TRD 802 (Group III Steam Boilers, Clause 11
in particular) must be observed.
272/273
E.2.1
Installation of category IV
land-based steam boilers
In the following, partial reference is made
solely to the installation of land-based steam
boilers (indicated accordingly with an "L" in
TRD 403), for example:
„Clause 3.1 - structural requirements
„Clause 3.2 - installation requirements
„Clause 3.3 - clearances for operation
and maintenance
„Clause 3.3.1 - minimum height/width of
the accessible area 2 m/1 m; restriction of
the minimum width to 0.8 m by valves
„Clause 3.3.2/3.3.3 - minimum width
in areas that need not be accessed for
operation or maintenance 0.5 m; 0.3 m
in the case of cylindrical boiler bodies
(at one side)
„Clause 3.3.4 - minimum clearance
between boiler top edge and ceiling lower
edge 0.75 m
„Clause 3.4 - access to boiler rooms
„Clause 4 - installation in enclosed spaces,
with specific reference to:
„Clause 4.1 - definition of the enclosed
spaces in which group IV boilers may be
installed (neither in, above, below nor
next to living spaces; neither in, above nor
below social spaces and working areas)
„Clause 4.2./4.3 - exceptions for the
permissible installation of so-called
product-pressure boilers
Note regarding Clause 4.3
An area of at least 10 % of the floor area of the
installation room must give way much more
easily on the outer walls or ceiling surfaces
than the rest of the enclosing walls.
„Clause 4.4 - escape routes and
emergency exits
„Clause 4.41 - it must always be possible to
leave and access the boiler room quickly
and freely via the escape routes
„Clause 4.4.2 - for land-based steam
boilers, linear distance of no more than
35 m to the exit
„Clause 4.4.3/4.4.4 - boiler rooms
with at least two exits, if possible on
opposite sides
„Clause 4.4.5 - exit clear width at least
0.6 m, minimum height 2 m
„Clause 4.4.6 - escape doors opening in
escape direction and able to be opened
from the outside without a key during
boiler operation
„Clause 4.5/4.6 - connecting paths
from installation room to other rooms;
separating walls and ceilings between
installation room and other rooms
„Clause 4.7/4.8 - ventilation of boiler rooms
in such a way that negative pressure of no
more than 0.5 mbar results
„Clause 5 - open air installation
„Clause 6 - walkways and railings
„Clause 7 - flue gas discharge
„Clause 8 - fuel storage and supply
„Clause 9 - contact protection
„Clause 10 - lighting
„Clause 11 - electrical equipment and
lightning protection systems
E.2.2
Installation of category III landbased steam boilers (TRD 802)
Partial reference solely to Clause 11 installation:
In this context the respective state building
regulations must be observed. In general,
siting of boilers in working areas is not out of
the question.
E.2 Requirements and regulations
Note
See chapter G1,
Appendix 4 for an example
sketch of an installation
room (container facility).
E.2.3
Steam boiler system
installation room
E.2.3.1
General requirements for
building/geometric data
and structural physics
Architectural and design aspects are not
considered here and must be clarified on site
in individual cases.
The specific requirements for fire resistance
levels to be complied with for building
components according to DIN 4102 and/or
DIN 13501 must be observed on the basis
of the respective applicable state building
regulations. The same applies to equipment of
smoke extraction systems and escape routes.
Subsoil and foundations
According to details specified in an expert's
report to be prepared on site for subsoil
assessment and recommendation of
foundations.
Assumed loads
According to DIN 1055 and/or according to
specification of the technological building
guidelines derived from unit loads, transport
and assembly loads.
Live loads
According to DIN 1055 and/or according to
VGB guideline VGB-R 602 U "Specification and
handling of effects on building structures in
power stations", 2005 edition.
Within a range of five metres from installation
openings, the live loads must be designed
accordingly for the expected installation loads.
Building structures
Reinforced concrete structures or steelframed structures, made from uprights,
beams and ties with threaded assembly joints,
are preferred.
Ceilings
According to operational requirements;
reinforced concrete ceilings, steel/concrete
composite ceilings on permanent sheet steel
shuttering, for example grating platforms.
Roof ceilings
Concrete roof ceilings in the form of in-situ
concrete or prefabricated ceilings.
For subordinate buildings, trapezoidal
panels can be integrated in consultation
with the developer and according to
static requirements.
Emergency staircases
Insofar as these are necessary due to the
building dimensions and/or building use; solid,
fire-resistant, brickwork or reinforced concrete
structures with facing brickwork or facing
concrete on the inside.
Thermal/sound insulation
According to DIN 4108/4109 for walls and roofs
and/or according to noise impact assessment.
External walls
If no higher level requirements apply for
design reasons:
„External wall surfaces in the form of
a double-skin, thermally insulated and
soundproof wall covering comprising
horizontally arranged self-supporting 60 cm
high sheet steel caissons - galvanised and
coated in standard colours. Perforated
design in areas where sound-absorption
measures are required
„Thermal insulation and/or soundproofing
made from mineral fibre panels inlaid
into the sheet steel caissons. Vertically
arranged trapezoidal sheet covering on
the outside, made from aluminium, coilcoated in RAL colour; profile and colour as
required by building owner
„For subordinate buildings without any
soundproofing requirements, sandwich
elements consisting of sheet aluminium
on both sides with a rigid PUR foam core
can be employed in consultation with the
building owner
Internal walls
„Made from lime-sand brick, thickness
according to structural requirements,
skimmed on both sides, if no higher level
demands are made of the wall surface
274/275
Roof sealing
For solid roofs, for example reinforced
concrete ceilings, aerated concrete
ceilings etc., the following roof structure
is conceivable:
„Primer (bituminous)
„Vapour barrier V 60 S4 AI 01
„Non-flammable thermal insulation,
thickness according to requirements,
with slope
„One layer KSA cold glue film
„One layer 200 PYE PV S5
„One layer PYP PV 200 S5 EN
„Separating layer of fibrous web or PE film
„Mechanical fastenings according to
structural requirements
„6 to 8 cm gravel ballast layer of washed
round gravel 16/32 mm
„Surfaces and walkways that are walked on
for operational or maintenance purposes
must be covered with 50/50/5 cm paving
slabs on protective building mats
For light roofs: (subordinate buildings)
„Trapezoidal panel roofs
„Thermal insulation made of foam glass;
thickness according to requirements
„1 layer Evalon-V
To provide fall protection, external walls must
be extended to at least 0.3 m above the upper
edge of the finished roof to form a parapet.
Stairs, platforms, railings, ladders
Design engineers must take account of
all potential damage and faults considered
possible based on their knowledge and
experience in the layout of stairs and
platforms. In particular, endangering of the
operating personnel must be minimised by
providing adequate means of escape.
It must be ensured that the distance of
the escape routes from rooms at risk to
an emergency exit does not exceed that
demanded by the building regulations.
At the same time, the emergency exit must
open either directly into the open air or
directly into an safety stairwell. On principle,
there must always be two escape options, if
possible diagonally opposite one another.
The stairs, platforms and ladders should permit
easy and safe access:
„to all access openings, inspection ports
and cleaning apertures,
„to parts of the system that require regular
checks or maintenance,
„to the equipment that must be actuated
manually, either normally or in the event
of a fault.
Ladders should only be provided in exceptional
circumstances.
The vertical clearance above all platforms and
stairs must be at least 2.10 m. The layout of
stairs and platforms must be coordinated with
the building owner.
Walkways, stairs
Frequently used walkways and stairs, as well
as escape routes, should have a minimum
width of 1.20 m; narrower widths are possible
in consultation with the building owner.
Step ratios for stairs required by building
legislation: h/a ≤ 19/26 cm ≤ 36°
Other stairs: h/a ≤ 20/23 cm ≤ 40° (see also
DIN 18065 and DIN 31003)
Stairs must be implemented in the form of
solid, pre-cast concrete steps with slip-proof
edge protection profiles embedded in the
concrete and/or grating steps according to
DIN 24531 with slip-proof leading edges.
Gratings
According to DIN 24531, type SP, 40 mm high,
mesh side 30 mm, supporting bar 40 x 3 mm.
The gratings are provided with an outer border,
even in recesses for pipes etc. The gratings
must be secured against displacement by
positive clamps at the 4 corners of each
individual element.
Railings and ladders
Made of round tubing according to DIN 24533,
but with rungs made of square steel bars.
E.2 Requirements and regulations
E.2.3.2
Building services equipment
Heating
Buildings must normally be equipped with
a domestic hot water heating system. The
exceptions are all electrical, instrumentation
and control rooms, IT systems, transformer
and switchgear rooms. In principle, these
spaces are heated with electric radiators or
wall mounted or ceiling mounted electric
fan heaters. In areas for boiler and machine
houses, as well as district heating stations,
where low pressure steam is available, this
steam could be used for heating.
The heating system is designed in such a
way that a room temperature of +5 °C can be
maintained at a minimum outside temperature
of -25 °C. In this design, it is ensured that
water-bearing parts cannot freeze up.
Furthermore, the heating system is designed
in such a way that at a standard outside
temperature according to DIN 4701 of 12 °C,
the following temperatures can be maintained:
„System rooms +18 °C
„Operations rooms +18 °C
„Offices and common rooms +20 °C
„Changing, wash and shower rooms +24 °C
„Pure traffic areas, such as stairwells
and passageways, and rooms in which
no water-bearing system parts are
situated +15 °C
Ventilation
Part of the exterior glazing must be equipped
with opening windows (with storm protection)
for the purpose of ventilating existing offices
and common rooms. Cross ventilation must
be possible. If window airing is not possible,
natural ventilation must be provided with
forced or mechanical ventilation.
Mechanical operations rooms, such as turbine,
boiler, pump and similar rooms, must be
ventilated. Ventilation systems are designed on
the basis of the following criteria:
„the required temperatures;
„the amount of heat released in the room;
„the amount of combustion air;
depending on which of these criteria makes
the greatest demands on the ventilation
systems. Otherwise, the ventilation systems
must be designed according to DIN 1946.
The necessary unrestricted air intake and
exhaust vents for the steam boiler room must
be provided here on the basis of the formula
in section D.3.4.
Technical operations rooms,
such as transformer, switchgear and electrical
systems rooms, must be equipped with
their own ventilation systems. The design of
these systems is governed by the respective
technical requirements and relevant official
regulations, DIN, VDI and other guidelines.
If cooling by outdoor air is dispensed with
in electrical operations rooms due to the
temperatures being too high and they are
cooled instead by circulating air coolers,
a minimum outdoor air content must be
provided by means of simple air change.
Areas with permanent workplaces, such as
offices and workshops, must be ventilated
in accordance with [German] workplace
regulations (ArbStättV) and DIN 1946.
Common rooms, changing, shower and
washrooms must be ventilated in accordance
with the ArbStättV and/or DIN 18228 and
DIN 1946. Interior WC rooms without windows
must be ventilated according to DIN 18017.
276/277
Smoke and heat extraction systems must
be provided for all areas with relevant fire
hazards. The smoke and heat extraction
system is dimensioned according to
DIN 18230 (structural fire protection in
industrial buildings).
Sanitary installations
Sanitary installations may only be installed by
registered contractors.
Town water pipes
Made of copper. Otherwise according to
guidelines from the responsible water supply
utility; cross sections and routing according
to DIN 1988.
Domestic hot water systems are coupled
according to DIN 1988 with the drinking
water and designed in compliance with AD
datasheet A3.
Hot water pipes and DHW circulation pipes
must be insulated. The insulation thickness is
governed by DIN 18421 and must be designed
according to VDI 2055.
Pipes laid beneath plaster must be fully
insulated and must not come into contact
with the brickwork. All insulating materials
may only be provided in flame-resistant or
incombustible versions.
Drain pipes
must be designed according to DIN 1986.
Collector pipes and downpipes must be made
from socketless drain pipes (SML) with pipe
connection up to DN 100 by means of AKO
rapid connectors and from DN 125 with CV
connectors. The connection lines to pieces of
equipment must be laid beneath plaster in HT
piping. Sizing according to DIN 1986.
Fire extinguishing equipment
Insofar as the local authorities have no other
requirements, preference should normally
be given to the provision of hand-held fire
extinguishers. These should however be
provided in adequate numbers in coordination
with the local fire department and the
building owner.
E.2.4 Acoustic emissions
Sources of noise
Sound is understood as mechanical vibrations
and waves in elastic media, such as solid
bodies (structure-borne noise), air (airborne
noise) and liquids. These vibrations occur at
certain frequencies (= number of vibrations
per second). The human ear perceives vibration
from approx. 16 Hz (low notes) to approx.
16,000 Hz (high notes).
Any type of sound perceived as annoying or
irritating by the human ear is described as
"noise". To prevent noise creating a nuisance,
the legislator [in most countries] has issued
regulations for protection against noise.
These include the German Immissions Act
(BImSchG), DIN 4109, DIN 45 680 and VDI
Guideline 2058. Limits, testing and evaluating
processes are defined here as a function of
the different environments and times of day.
The noise emanating from boiler systems is
mainly caused by the following:
„Combustion
„Burner fan
„Structure-borne vibrations
„Pump motors
Airborne noise is predominantly created by
the combustion process and transmitted
by emissions from the burner, boiler and
flue. Structure-borne noise is generated by
mechanical vibration in the boiler system and is
generally transmitted through the foundations,
walls and sides of the flue system. Depending
on the frequency, sound pressure levels of
between 50 and 140 dB(A) can arise.
E.2 Requirements and regulations
Selected noise protection measures
Sound-insulating bases can only be supplied up
to a limited load-bearing capacity. Furthermore,
separation can only be achieved by structural
means, such as anti-vibration foundations.
A) Structure-borne noise insulation
Sound-insulating boiler supports minimise the
transmission of structure-borne noise to the
floor surface.
B) Flue gas silencers
Flue gas silencers are used for the attenuation
of combustion noises. To ensure effectiveness,
their design must be carefully coordinated with
the boiler/burner combination, the flue system
and the chimney.
When planning the size of the installation
room, attention must be paid to the fact that
the flue gas silencer requires a considerable
amount of space.
C) Flue expansion joints
Flue expansion joints prevent the transmission
of structure-borne noise from the boiler/burner
unit via the flue path to the building structure.
In addition, they can absorb the thermal
expansion of the flue pipes.
D) Burner fan – silencer hoods
Silencer hoods are used to attenuate burner
fan noises. Their main purpose is therefore
to reduce the amount of noise within the
installation room.
E) Air intake and exhaust
Balanced flue systems with silencers
supply the burner with specific amounts
of combustion air and prevent the outward
transmission of noise generated in the boiler
room via vents.
We recommend that provision be made for
noise prevention measures as early as the
planning phase to avoid costly retrofitting. One
prerequisite for an optimum solution is close
collaboration between architects, developers,
design engineers and contractors.
The contact point for clarifying emission
requirements is the local factory inspectorate.
E.2.5 Transportation and handling
A) Transportation
Shell boilers can be transported by road,
rail or water. Packaging must be designed
appropriately for the means of transport;
where necessary, the particularly fragile
thermal insulation is shipped separately.
Accessories such as burners, control
equipment and valves are packed and shipped
separately to protect them from damage in
transit. A further benefit of this approach is
minimum possible transport dimensions.
Accessories are fitted only after the steam
boiler has been installed on site.
The higher the steam output, the more
expensive the transportation. In certain
circumstances, forwarding agents take
account of appropriate transport routes
(e.g. consideration of narrow roads and low
bridges, the load-bearing capacity of transport
routes) and police escorts (special transports).
The developer must ensure that there is
adequate access to the installation location on
site. The access route must provide sufficient
load-bearing capacity (no underground tanks or
underground car parks). In addition, sufficient
space for manoeuvring must be available.
Suitable lifting equipment for unloading the
boiler and accessories and for handling heavy
equipment (e.g. burner, pumps, valves,
control panel etc.) must be provided in the
boiler house.
B) Moving into the building
An adequately sized opening must be provided
for bringing the boiler and the additional
components into the building. This opening
may also be in the boiler house roof or take
the form of a shaft.
To reduce costs, the handling paths should
be as short as possible and not restricted by
obstructing elements. Sufficient load-bearing
capacity must also be ensured in this area.
Lifting gear should be able to be sited as close
to the installation location as possible. It must
be adequately sized for the loads to be lifted
and the heights and/or reach to be covered.
Lifting equipment requires a sufficiently solid
floor area. In certain circumstances, it may be
necessary for access roads or sections of road
to be closed temporarily.
278/279
E.2.6
E.2.6.1
Earthquake protection
Basic principles
When designing boiler houses in earthquake
zones, it is essential that certain requirements
for producing an earthquake-proof supporting
structure are considered at an early stage.
The basic task of earthquake protection is,
by means of modelling, design and sizing,
to direct and distribute the vibration energy
transferred to the boiler house by earth
movements and convert it into other forms
of energy in such a way that major damage is
prevented. Attention must therefore be paid
to a clearly designed supporting structure
with extensive regularity both in the floor
plan and extending above the height of the
boiler house.
Aside from the vertical load-bearing elements,
the shearing action of the floors is very
important with regard to spatial load-bearing
capacity and rigidity. The engineering design
of the foundations and their connection to
the boiler house that sits on them must
ensure that large relative displacements of
the foundation structures among themselves
is prevented and the entire building structure
is loaded uniformly by the movement of
the earthquake.
The stresses applied by an earthquake can
be better appreciated and considered more
accurately in the design due to the required
regularity of the boiler house floor plan
and elevation.
Aside from the regularity of the structure,
other important features must be examined,
such as natural frequencies and damping of
the structure. This should take place above
all with reference to the constraints of the
earthquake loads to be assessed. If necessary,
appropriate measures must be provided to
modify the natural frequencies and/or damping
action. Such products as "protective elements"
and/or "spring/VISCO® damping elements" can
be used for this purpose.
E.2.6.2
Steam boilers
For boilers installed within an earthquakeproof boiler house, the earthquake impact
on the boiler must be examined. This may
require limitation of the acting forces and/or
accelerations. However, the basic requirement
is that the boiler(s) is/are installed on a
foundation that has been included in the
calculations for earthquake protection.
E.2.6.2.1
Boiler accessories
The specifications in item E.2.6.2 apply equally
to ancillary components, such as pumps
and thermal/chemical tanks. Calculationbased verification of ability to withstand the
respective loads (structural analysis) must
be furnished for feedwater tanks, which are
normally mounted on a frame.
Chimneys must be designed for buckling
prevention, even if they are installed in the
building. Wind loads must be considered due
to the construction height and the geodetic
altitude of the installation location.
E.2 Requirements and regulations
E.2.6.3
Pipes
In addition to static and dynamic operational
loads, pipes in the boiler house must be
designed to withstand the dynamic loads
induced by an earthquake.
Pipes only have insignificant inherent
damping properties. Dynamic excitation due
to operational or abnormal occurrences,
such as an earthquake, is therefore always
particularly critical if the excitation frequency
corresponds to the natural frequency of the
pipework. In order to restrict pipe movements
to a permissible level, it may be necessary
to provide for measures that increase
damping here.
Pipes that penetrate the boiler house wall, i.e.
fuel, blow-off, steam, electrical and water inlet
and outlet lines, must be routed in such a way
that deformation of the body to be penetrated,
as well as the pipes themselves, is prevented.
Irrespective of the correctly and and safely
implemented pipework design, pipes bearing
hazardous materials (steam, oil, gas etc.) must
be protected against earthquakes with a quickclosing system that reliably inhibits leakage of
the medium.
E.2.6.4
Earthquake-proof planning of
openings and slits in walls
In principle, earthquake walls with openings
or slits must be regarded as individual
walls that have a lower shearing resistance
independently of one another than a single
homogeneous wall. Electrical lines and piping
must be planned in such a way that they impair
the shearing resistance of a wall to the lowest
extent possible.
E.2.6.5
Earthquake standards
Applicable building standards for earthquake
safety must be considered in the project
on a country-specific basis. In Germany, for
example, DIN 4149 "Earthquake protection
of solid structures" must be observed.
280/281
Vitomax 200-HS, type M237
2 Vitomax 200-HS, type M237, mirrored design
SSAO Servolux, Lithuania,
3 x Vitomax 200-HS 4 t/h; 13 bar.
282/283
F Operation
The following chapter deals with the operating modes and regulations for
operation in Germany.
Different regulations may apply in other
countries. If applicable, the country-specific
legislation must therefore be considered.
The basis for operation in Germany is the
[German] Health & Safety at Work Act
(BetrSichV) and the associated technical
regulations for operational safety (TRBS).
283
F Operation
284
Operating modes
284
286
287
F.1.1
F.1.2
F.1.3
Operating modes
Standards and regulations governing operation
Inspection intervals for boilers according to the
Pressure Equipment Directive
F.1 Operation
Operating modes
Depending on the respective equipment level, the TRD differentiates between several
operating modes for high pressure steam systems.
F.1.1
Operating modes
1. Operation with constant direct
supervision
In this operating mode, the boiler must be
subject to constant supervision by an operator.
Automatic equipment for regulating the water
and pressure levels are therefore superfluous
in this mode. Such functions can be carried out
by the operators.
2. Operation with limited supervision
The operator must personally verify the correct
state of the boiler system every two hours.
The boiler must be equipped with control
equipment for water and pressure levels.
3. Temporary unattended operation with
reduced operating pressure
In the unattended operating mode, the steam
boiler is operated with a safety pressure
of 1 bar. This operating mode requires that
additional equipment (safety valve, pressure
regulator, pressure limiter, pressure gauge) are
installed on the boiler.
4. Operation without constant supervision
for a period of 24 hours (BosB 24h)
The steam boiler must operate fully
automatically and be equipped with two selfmonitoring pieces of safety equipment for
limiting the water level at the lowest possible
water level. Combustion with additional
safety equipment must also be approved for
unattended operation.
284/285
5. Operation without constant supervision
for a period of 72 hours (BosB 72h)
In addition to the requirements for 24-hour
unattended operation, the high water level
must also be limited in this mode using a
separate switching amplifier. Furthermore,
limiters for the maximum conductivity of the
boiler water and equipment for monitoring
the water quality (top-up water, condensate)
are required and additional control panel
requirements must be met.
The operating modes described in points
1 to 3 are practically irrelevant today.
Due to the current standard of safety
technology and equipment reliability, new
boiler systems are equipped for unattended
operation for a period of 24 or 72 hours. The
present trend is towards unattended operation
for 72 hours (BosB 72h). The following
aspects must be observed as a condition for
unattended operation:
The operator must carry out the test
procedures specified in the operational
requirements, record their completion in the
operator's log and confirm such entries with
his/her signature. A time switch for complying
with the test intervals is not compulsory.
In addition, a contractor, such as Viessmann
Industrieservice, must conduct an inspection
every six months of control and limiting
equipment that is not subject to the regular
checks by the operator.
With this type of equipment, the operator's
responsibilities are extended to include
maintenance, therefore demanding a greater
in-depth knowledge than is necessary for the
operation of simpler systems.
In conjunction with advanced control systems
(e.g. PLC), it is possible to transfer boiler data
to a control centre. Control functions can
also be triggered from this control centre.
Furthermore, automatic fuel changeover is also
possible for dual-fuel combustion systems.
The boiler must always be manually reset on
the boiler itself after a safety shutdown has
taken place.
Note (for Germany)
The amendment
to the BetrSichV
dated 18 December
2008 stipulates that,
with effect from
31 December 2012, all
technical regulations
(TRD), which are no
longer maintained
following introduction of
the Pressure Equipment
Directive, will lose their
validity, i.e. by this date,
all the old technical
regulations must have
been superseded by the
new TRBS.
Quality requirements
will be governed by the
EN regulations.
F.1 Operation
F.1.2
Standards and regulations
governing operation
In Germany, the principle regulation for
operation is the BetrSichV ([German] Health
& Safety at Work Act). Paragraph 12 thereof
stipulates that systems must be operated in
accordance with the rules formulated by the
Commission for Health & Safety at Work at the
Federal Ministry for Labour (BMA) (Technical
Regulations for Operational Safety – TRBS).
However, these regulations are not yet
completely available at the moment.
Consequently, the TRD still apply to steam
boilers in accordance with the transitional
regulations. New systems may only be
operated after the "Inspection prior to
commissioning" has been carried out. For
boilers in category III and IV, this inspection
must be conducted by the approved
monitoring body (ZÜS), which certifies the
correct condition of the system.
Personnel trained in operating the system
must be available during commissioning. For
high pressure systems, these are qualified
boiler operators who have completed an
approved training course [in most cases, at
the German Technical Inspectorate [TÜV]).
Individuals who have the relevant technical
knowledge on account of their training are
considered to be of equal status.
Correct operation also requires the use of
operating instructions. These instructions must
contain all information required by the operator
for operation, maintenance and inspection
work. This also includes a list of the actions
operators must take on each individual piece
of boiler equipment and at what intervals
(see operating and service instructions for the
Vitomax 200-HS).
An operator's log must be available for each
boiler where all inspections are recorded, and
each entry is confirmed by the signature of
the person carrying out the inspection. The
log serves the purpose of verifying correct
operation and maintenance of the boiler
system and must be submitted as and when
required to the authorised inspector and the
relevant regulatory authority.
Paragraph 3 of the BetrSichV stipulates the
compulsory requirement for employers to
prepare a risk assessment. In preparing the
assessment, all risks must be identified that
could arise in the area of the steam boiler
system, with the aim of ensuring provision and
evaluation of the equipment without risk.
Category III high pressure steam boilers (for
a product of volume in litres and maximum
permissible pressure in bar exceeding 1000)
and those in category IV are subject to regular
inspections by the approved monitoring body
(ZÜS).
According to paragraph 15 of the BetrSichV,
operators are obliged to notify the relevant
authority of the inspection intervals they
have determined within six months of
commissioning. The approved monitoring
body must verify the determined inspection
intervals. In the event of disagreement
between operator and approved monitoring
body regarding these intervals, the authority's
decision is final and binding.
The inspection intervals are based
on specifications issued by the boiler
manufacturer, who makes relevant
recommendations in the Declaration of
Conformity. According to the [German]
Health & Safety at Work Act (BetrSichV), the
maximum intervals are as follows:
„External inspection 12 months
„Internal inspection 3 years
„Strength test 9 years
These intervals must not be exceeded.
286/287
F.1.3
Inspection intervals for boilers
according to the Pressure
Equipment Directive
The design work carried out by Viessmann
in accordance with current regulations leads
to the longest possible inspection intervals
during operation. Viessmann prepares designs
in accordance with TRD in conjunction with
the trade association agreements and under
consideration of the DIN/DIN EN standards.
As a manufacturer, we recommend the
following inspection intervals a) for our
products:
„An expert inspection every six months.
This can also be conducted by Viessmann
Industrieservice (same scope as the annual
inspection)
„After one year, external inspection by
the approved monitoring body (ZÜS). All
safety equipment (safety valve, control and
limiting equipment, condition of threaded
fittings, state of the system, expertise of
boiler operator, inspection of the operating
log). The boiler may be operational
„After 3 years in operation, internal
inspection by the approved monitoring
body (ZÜS). At the same time, the boiler
is inspected and all components examined
on the water and gas sides
„After nine years, a strength test (water
pressure test) by the approved monitoring
body (ZÜS)
F.1.3.1
Requirements for regular
inspection according to TRD 505
– external inspection –
A) Scope
This guideline applies to the external
inspection of all Vitomax high pressure steam
and high pressure hot water boilers with the
following parameters: TS > 120 °C, PS > 1 bar,
which are employed as land-based steam
boilers for generating high pressure hot water
and steam.
B) Inspection intervals
See Declaration of Conformity (e.g.
Vitomax 200-HS type M75A, Fig. C14.1-3) for
the respective boiler type. The intervals begin
after the system has been commissioned.
Insofar as internal inspections are due at the
same time, the external inspection must take
place on conclusion of the internal tests.
C) Extent of the external inspection
The regular external inspection of the steam
boiler system extends to the steam boiler and
the components of the steam boiler system,
i.e. every piece of equipment required for
operating the boiler system.
Based on our Declaration of Conformity, the
operator recommends the aforementioned
inspection intervals to the relevant authority.
The authorised inspector from the approved
monitoring body either agrees or demands a
shorter inspection interval. Until now, neither
Viessmann Werke nor Viessmann customers
have experienced any difficulties with this
procedure.
a)
see also Appendix. G, Tb.10.
F.1 Operation
D) Execution of the regular external
inspection
On carrying out the inspection, e.g. function
test, the operation will be interrupted. No
hazardous conditions may arise in the system
due to testing. The system operator is
responsible for identifying any defect, damage
or unusual occurrence that comes to light
during the observation period.
Compliance of the system with the permit and
the system condition are generally checked
in accordance with the following points,
whereby the system is inspected together
with the operator or a person authorised by
the operator.
D1) Assessment of the general system
condition, namely:
the boiler components and hot water
expansion vessels that are accessible during
operation, the spot check of the combustion
chamber through inspection ports, the
sheet metal casing, the thermal insulation,
the closures, the inspection ports, the
determination of leaks, signs of condensation,
discolouration and vibration.
„Combustion and the fuel supply/charging,
storage and treatment equipment, air
lines, air pre-heaters, flue ducts and flue
silencers
„Feedwater, steam, hot water, drain and
dewatering lines
D 2) Safety-related equipment on the
water and steam side, namely:
devices for limiting water level, pressure and
temperature with regard to their function;
controllers only insofar as they fulfil a safety
function
„Feed pump operational availability
„Network circulation pump operational
availability
„Safety equipment to prevent excess
pressure: response pressure, function:
safeguarding against unintentional
adjustment
„Pressure maintaining equipment in hot
water systems with external pressure
maintenance; determination of the
switching points and changeover testing, if
applicable
„Flue gas non-return devices, shut-off and
drainage equipment
D 3) Safety-related combustion equipment
with regard to function:
„Equipment on fuel tanks
„Safety equipment on fuel oil pre-heaters
„Fuel supply lines and equipment, including
valves for easily flammable, liquid and
gaseous fuels
„Safety shut-off equipment, also checking
for tightness and tightness/leak testing
equipment
„Burner, shut-off and actuating equipment
for combustion air, air shortage prevention
devices, ignition equipment, flame
monitoring equipment, fuel/air control
equipment, safety equipment leading to
a shutdown, giving due consideration to
the possible operating modes, safety,
maintenance, flushing and ignition times
„Observation apertures for the combustion
chamber, the burner lining and the flame
appearance
„Devices for combustion chamber pressure
regulation
288/289
D 4) Safety power circuit
The safety power circuit of the steam boiler
system is tested for such possible faults that
cannot be established as part of the function
test on individual pieces of equipment.
D 5) Operating mode
Visual inspection of the operating records
regarding the quality of the feedwater and
boiler water as well as inspection of the
additional equipment for operation with limited
supervision or without constant supervision.
D 6) Operation
A check is made with regard to the availability
of suitable operating instructions and the
familiarity of operating personnel with the
operation of the boiler system.
E) Test certificate
The tester must produce a report of the
inspection (see EN 12953-6, Appendix C) and
suitable measures must be initiated if defects
are discovered.
F.1.3.2
Requirements for regular
inspection according to TRD 506
– internal inspection –
A) Scope
This guideline applies to the internal inspection
of all Vitomax high pressure steam and high
pressure hot water boilers with the following
parameters: TS > 120 °C, PS > 1 bar, which
are employed as land-based steam boilers for
generating high pressure hot water and steam.
B) Inspection intervals
The interval for the recurring internal
inspection is three years1). The intervals begin
after the system has been commissioned. An
internal inspection must be conducted prior to
re-commissioning if the steam boiler has been
non-operational for more than two years.
C) Extent of the internal inspection
The recurring internal inspection extends to
the steam boiler and the feedwater pre-heater
located in the flue gas flow of the combustion
chamber.
The steam boiler includes all the equipment
and lines associated with the boiler, including
the shut-off equipment. This does not apply
to parts connected with the inlet, outlet and
drain lines that can be shut off from the boiler
and those parts in which the generated steam
is superheated that can be shut off from the
boiler, unless these are located wholly or
partially inside a container that is part of the
steam boiler.
Fig. F.1.3.2-1
Inspection intervals for recurring internal testing in selected member states
D
F
B
I
L
NL
GB
S
Pressure vessel
5
1.5 - 3
1-3
1-2
5
4
2.17
3
Steam boiler
3
1.5
1
2
1.5
2
1.17
1
1)
= country-specific.
F.1 Operation
D) Execution of the recurring internal
inspection
The recurring internal inspection is generally
confined to a visual inspection that may
be carried out, if necessary, using suitable
auxiliary means, such as inspection devices
(endoscopy), or by additional simple testing,
such as measuring the wall thickness or
checking for surface cracks.
If there is other cause (operating mode) to
assume the existence of damage that cannot
be detected with the means mentioned in the
previous section, additional inspection actions
are required that extend beyond the general
scope. Normally, these are test methods such
as supplementary water pressure checks,
ultrasound testing, material tests, surface
crack inspections and chemical analysis of
deposits.
D1) The recurring internal inspection is
carried out as follows:
boiler jackets and floors, flame tubes, reversing
chambers and similar are inspected, insofar as
they are accessible, taking into consideration
the welded and threaded connections, the
flanges, the anchors (end anchor, tensioning
anchor and similar), the connectors, the pipe
connections, the attachment and condition
of built-in parts, the manhole covers and the
inspection ports.
Deposits are assessed. The walls on the
flue gas and combustion side and the
external walls are inspected, insofar as
they are accessible, in particular the flame
tubes, flanges, connectors, manhole covers,
inspection ports and boiler supports. The
boiler body insulation need not be removed for
conducting these inspections.
Profiles and fittings are inspected externally,
whereby particular attention is paid to welding
seams, flange collars, brackets and supports.
Casings for water level controllers and limiters
are also inspected internally. For other fittings,
the following section applies.
Flue gas feedwater pre-heaters are visually
inspected on the flue gas side; on the water
side, only insofar as detachable closures are
available. The inspection includes checking
for corrosion, particularly as a result of
temperatures falling below the dew point.
E) Test certificate
The tester must produce a report of the
inspection (see DIN EN 12953-6, Appendix
C) and suitable measures must be initiated if
defects are discovered.
290/291
F.1.3.3
Requirements for regular
inspection according to TRD 507
– water pressure testing –
A) Scope
This guideline applies to the external
inspection of all Vitomax high pressure steam
and high pressure hot water boilers with the
following parameters: TS > 120 °C, PS > 1 bar,
which are employed as land-based steam
boilers for generating high pressure hot water
or steam.
B) Inspection intervals
The interval for the recurring water
pressure test is normally nine years1). The
intervals begin after the system has been
commissioned.
B1) Extent of the water pressure test
The recurring water pressure test extends to
the steam boiler and the feedwater pre-heater
located in the flue gas flow of the combustion
chamber.
C) Execution of the recurring water
pressure test
C1) Test pressure level
Test pressures must not exceed those applied
during the first water pressure test.
„For Vitomax: see type plate2)
„For Turbomat: see approbation drawing
For flue gas water pre-heaters, the test
pressure is equal to the test pressure level of
the associated steam boiler.
C2) Applying and maintaining the
test pressure
The test pressure must be applied in the
presence of the authorised inspector, after
the components to be tested have previously
been subjected to operating pressure.
Where no alternative values are stated by the
manufacturer, the rate of pressure change
must not exceed 10 bar per minute up to
approx. 75 % of the test pressure and
thereafter approx. 1-2 bar per minute.
The test pressure must be applied for approx.
30 minutes before the authorised inspector
begins testing the pressurised components.
The test pressure must be checked with a test
pressure gauge.
For steam boilers and system components
with test pressures of up to 42 bar, test
pressure must be maintained for the entire
duration of the test. In the case of test
pressures in excess of 42 bar, the pressure
prior to ramping to the level of the permissible
operating pressure must not fall below 42 bar.
When reducing the pressure, the rate of
pressure change should correspond to that
when the pressure was applied.
C3) Water requirements
Water used for filling the system must not
contain any coarse contaminants. Under
consideration of the operating conditions, the
water must not contain any constituents that
would attack or contaminate the walls. During
inspection, the filling water temperature
should not exceed 50 °C.
C4) Visual inspection of the walls
Pressurised components must be checked
visually for the presence of cracks,
impermissible deformation and leaks. Visual
spot checks are permissible if the authorised
inspector can assess the safety-relevant
condition of the system components to be
tested on the basis of these checks. The
thermal insulation is removed as far as is
appropriate if there is good reason to assume
that damage has occurred.
D) Test certification
The tester must produce a report of the
inspection (see DIN EN 12953-6, Appendix
C) and suitable measures must be initiated if
defects are discovered.
1)
Country-specific requirements must
2)
This ensures compliance with the
be observed.
requirements of TRBS 1201.
Vitomax 200-HS, 26 t/h, Austria
292/293
G Appendix
Technical data collection and tables
293
G Appendix
Technical data collection and tables
294
[A 1]
296
297
298
302
304
305
306
309
313
314
315
316
317
318
319
320
311
322
323
324
325
Standard circuit diagram; other diagrams
can be found in the cover inside pocket
[A 2.1] Thermal insulation of pipes
[A 2.2] Contact protection insulation
[A 3]
Technical Guide on water quality – extract
[A 4]
Sketch of steam boiler container system
[Tb. 1.0] SI units / conversion table
[Tb. 1.1] 1. Conversion table – BTU / BHP / KW / t/h
[Tb. 2.0] Steam table (saturation state)
[Tb. 2.1] Properties of superheated steam
[Tb. 2.2] Properties of saturated steam
[Tb. 2.3] Enthalpy/Entropy
[Tb. 3.0] Internal pipe roughness
[Tb. 3.1] Pipe friction factor / Reynolds number
[Tb. 4.0] Pressure drop in steam pipes
[Tb. 4.1] Pressure drop in steam pipes – example
[Tb. 5] Conversion for the units of water hardness
[Tb. 6] Re-evaporation in condensate expansion
[Tb. 7] Pipe cross section for given steam parameters – example
[Tb. 8] Pressure drop in water pipes for a particular flow rate – example
[Tb. 9] Flow velocities (standard values)
[Tb. 10] Steam boiler inspection checklist
Literature references
G.1 Appendices
[A 1] Standard circuit diagram
294/295
G.1 Appendices
[A 2.1] Thermal insulation of pipes
Ambient temperature: 9 °C
Wind speed: 5 m/s
Number of hours run: 8000 h/a
Cost-effective thermal insulation for pipes
°C
80
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
500
DN
10
40
40
40
40
40
40
40
40
40
40
40
40
40
50
50
50
50
50
60
60
60
60
15
40
40
40
40
40
40
40
40
40
40
40
50
50
50
50
50
50
50
60
60
60
60
20
40
40
40
40
40
40
40
40
40
50
50
50
50
50
60
60
60
60
60
70
70
70
25
40
40
40
40
40
40
40
40
50
50
50
50
50
50
60
60
60
60
70
70
80
80
32
40
40
40
40
40
40
40
40
50
50
60
60
60
60
60
60
70
70
70
80
80
80
40
40
40
40
40
40
40
40
50
50
60
60
60
60
70
70
70
70
70
80
80
80
80
50
40
40
40
40
40
50
50
50
60
60
60
70
70
70
70
70
80
80
80
90
90
90
65
40
40
40
40
50
50
50
60
60
70
70
70
70
80
80
80
80
90
90
90
90
100
80
40
40
40
50
50
60
60
60
70
70
70
70
80
80
80
90
90
90
90
100
100
100
100
40
40
50
50
50
60
70
70
70
80
80
80
80
90
90
90
100
100
100
100
110
110
125
40
40
50
50
60
60
70
80
80
80
90
90
90
90
100
100
100
110
110
110
110
110
150
40
50
50
60
60
80
80
80
90
90
90
100
100
100
100
110
110
110
120
120
120
120
200
40
50
50
60
80
80
80
90
90
100
100
100
110
110
110
110
120
120
120
150
150
150
250
50
50
60
60
80
90
90
90
100
100
100
110
110
120
120
120
120
150
150
150
160
160
300
50
50
60
80
80
90
90
100
100
100
110
110
110
120
150
150
150
150
150
160
160
170
350
60
60
60
80
90
90
100
100
100
110
110
120
120
120
150
160
160
160
160
160
170
170
400
60
60
80
80
90
100
100
100
110
110
120
120
150
150
150
160
170
170
170
170
170
190
500
60
80
80
90
90
100
100
100
110
110
120
150
150
160
160
160
170
190
190
190
190
190
600
60
80
90
90
100
100
100
110
110
120
120
150
160
160
170
170
170
190
190
190
200
200
700
60
80
90
100
100
100
110
110
120
120
150
150
160
170
170
180
180
190
190
200
200
200
800
80
80
90
100
100
100
110
110
120
150
150
160
160
170
180
180
190
190
200
200
200
210
900
80
90
90
100
100
110
110
120
120
150
160
160
170
170
180
190
190
200
200
200
210
210
1000
80
90
100
100
100
110
110
120
150
150
160
170
170
180
180
190
200
200
200
210
210
220
1100
90
90
100
100
100
110
110
120
150
160
160
170
170
180
190
190
200
200
210
210
220
220
1200
90
90
100
100
100
110
120
120
150
160
170
170
180
180
190
190
200
200
210
220
220
230
1400
90
90
100
100
110
110
120
150
150
160
170
180
180
190
190
200
200
210
210
220
230
230
1500
90
90
100
100
110
120
120
150
160
160
170
180
190
190
200
200
200
210
220
220
230
240
1600
100
100
100
100
110
120
150
150
160
170
170
180
190
190
200
200
210
210
220
230
230
240
1800
100
100
100
110
110
120
150
160
160
170
180
180
190
200
200
210
210
220
220
230
240
240
2000
100
100
100
110
120
120
150
160
170
170
180
190
190
200
210
210
220
220
230
230
240
240
2400
110
110
110
110
120
150
150
160
170
180
180
190
200
200
210
220
220
230
230
240
240
240
2800
110
110
110
110
120
150
160
160
170
180
190
190
200
200
210
220
230
230
240
240
240
240
3200
120
120
120
120
120
150
160
170
180
180
190
200
200
200
210
220
230
240
240
240
240
240
3600
120
120
120
120
120
150
160
170
180
190
190
200
200
210
210
220
230
240
240
240
240
240
4000
120
120
120
120
120
150
160
170
180
190
190
200
200
210
220
220
230
240
240
240
240
240
Flush
120
120
120
150
150
150
160
170
180
190
200
200
210
210
220
230
230
240
240
240
240
240
wall
296/297
[A 2.2] Contact protection insulation
Contact protection insulation [A 2.2]
Contact protection insulation on pipes and containers/cylinders
Design data:
Surface temperature on the weather jacket: 60 °C
Ambient air temperature: 20 °C
Wind speed: 3 m/s
Insulating material: mineral mat
DN/t
100
150
200
250
300
350
400
450
500
550
600
700
800
(°C)
10
40
40
40
40
40
40
40
40
40
40
40
50
70
15
40
40
40
40
40
40
40
40
40
40
40
60
80
20
40
40
40
40
40
40
40
40
40
40
50
60
80
25
40
40
40
40
40
40
40
40
40
40
50
70
90
32
40
40
40
40
40
40
40
40
40
50
50
70
90
40
40
40
40
40
40
40
40
40
40
50
50
70
100
50
40
40
40
40
40
40
40
40
40
50
60
80
100
65
30
30
30
30
30
30
30
30
40
50
60
80
120
80
30
30
30
30
30
30
30
30
50
50
60
90
120
100
30
30
30
30
30
30
30
40
50
60
70
90
120
125
30
30
30
30
30
30
40
40
50
60
70
100
130
150
30
30
30
30
30
30
40
40
50
60
80
100
130
200
30
30
30
30
30
30
40
50
60
70
80
120
140
250
30
30
30
30
30
30
40
50
60
70
80
120
150
300
30
30
30
30
30
30
40
50
60
70
90
120
160
350
30
30
30
30
30
30
40
50
60
80
90
120
160
400
30
30
30
30
30
40
40
50
70
80
90
130
170
500
30
30
30
30
30
40
50
60
70
80
100
130
180
600
30
30
30
30
30
40
50
60
70
80
100
140
190
700
30
30
30
30
30
40
50
60
70
90
100
140
190
800
30
30
30
30
30
40
50
60
70
90
120
150
200
900
30
30
30
30
30
40
50
60
80
90
120
150
210
1000
30
30
30
30
30
40
50
60
80
90
120
160
210
1100
30
30
30
30
30
40
50
60
80
100
120
160
210
1200
30
30
30
30
30
40
50
70
80
100
120
160
220
1400
30
30
30
30
30
40
50
70
80
100
120
170
240
240
1500
30
30
30
30
30
40
60
70
80
100
120
170
1600
30
30
30
30
40
50
60
70
90
100
120
170
240
1800
30
30
30
30
40
50
60
70
90
120
130
180
240
2000
30
30
30
30
40
50
60
70
90
120
130
180
250
2400
30
30
30
30
40
50
60
80
90
120
130
190
260
2800
30
30
30
30
40
50
60
80
90
120
140
190
270
3200
30
30
30
30
40
50
60
80
100
120
140
200
270
4000
30
30
30
30
40
50
60
80
100
120
140
200
280
30
30
30
30
30
30
30
40
50
60
70
100
140
Hori. +
vert. wall
G.1 Appendices
[A 3] Technical Guide on water quality - extract
7HFKQLFDOJXLGH±ZDWHUTXDOLW\IRUVWHDPERLOHUV\VWHPV
8VHRIWKLVWHFKQLFDOJXLGH
The specified limits apply to steam generators made from unalloyed
or low-alloyed steel. They are based on many years' experience
gained by Viessmann in the steam boiler sector as well as the minimum requirements specified by the EN 12953-10.
$LP
Maintaining the aforementioned water parameters enables system
operators
■ to reduce the risk of corrosion,
■ to reduce the formation of deposits,
■ and to safeguard the separation of sludge.
This facilitates safe, economical system operation over a long service
life.
6WHDPERLOHU
In its natural state, most untreated water will be unsuitable as boiler
feedwater. The type of boiler feedwater treatment should be matched
to the raw water quality. As its quality may change, regular checks are
required.
The water feed pipe downstream of the boiler feedwater treatment
should be equipped with a suitable water meter to record the volume
of top-up water added to the return condensate; this also provides an
indirect check on the steam draw-off volume.
In all circumstances, it is advisable to return as much condensate as
possible to the feedwater tank. The condensate may also have to be
treated so it conforms to the requirements of the boiler feedwater
(according to table 1).
These requirements, plus those appertaining to the boiler water
(according to table 2), mean that – depending on the condition of the
untreated water and the amount of top-up water – at the very least a
suitable chemical or thermal water treatment system should be installed and there should be a facility for adding oxygen binders (possibly
alkalines and phosphates) into the feedwater tank supply line.
The requirements are monitored by measurements made by suitable,
preferably uncomplicated devices (either every 24 h or 72 h or in line
with national requirements, subject to the mode of operation). These
test values, the volume of top-up water, the chemical consumption and
the required maintenance should be entered into a boiler log to enable
the operating conditions to be checked at any time.
7DEOH6DOLQHERLOHUIHHGZDWHUUHTXLUHPHQWV
3HUPLVVRSHUDWLQJSUHVVXUH
General requirements
pH value at 25 °C
Conductivity at 25 °C
Total alkaline earths (Ca2+ + Mg2+)
Oxygen (O2)
Bound carbon dioxide (CO2)
Iron, total (Fe)
Copper, total (Cu)
Oxidability (Mn VII ඎ Mn II) as KMnO4
Oil, grease
Organic substances
EDU
µS/cm
mmol/litre
mg/litre
mg/litre
mg/litre
mg/litre
mg/litre
mg/litre
—
XSWR
!
Colourless, clear and free of undissolved substances
>9
Only standard values applicable to boiler water
< 0.01
0.05
< 25
< 0.2
< 0.05
< 10
< 1
see footnote
>9
< 0.01
< 0.02
< 25
< 0.1
< 0.01
< 10
<1
7DEOH%RLOHUZDWHUUHTXLUHPHQWV
Silicic acid (SiO2)
2
EDU
)HHGZDWHUFRQGXFWLYLW\!—6FP
XSWR
!
10.5 to 12
mmol/litre
µS/cm
mg/litre
mg/litre
1 to 12
< 6000
10 to 20
)HHGZDWHUFRQGXFWLYLW\싨—6FP
!
Colourless, clear and free of undissolved substances
10.5 to 11.8
1 to 10
see Fig. 1, page 3
10 to 20
Subject to pressure; see Fig. 1 (page 3) and 2 (page 3)
10 to 11
0.1 to 1.0
< 1500
6 to 15
*HQHUDOO\RUJDQLFVXEVWDQFHVDUHPL[WXUHVRIGLIIHUHQWFRPSRXQGV7KHFRQVLVWHQF\RIVXFKPL[WXUHVDQGWKHFKDUDFWHULVWLFVRIWKHLUFRP
SRQHQWVXQGHUWKHRSHUDWLQJFRQGLWLRQVRIWKHERLOHUDUHKDUGWRSUHGLFW2UJDQLFVXEVWDQFHVFDQGHJUDGHLQWRFDUERQGLR[LGHDQGRWKHUDFLGLF
SURGXFWVWKDWZRXOGLQFUHDVHWKHFRQGXFWLYLW\DQGUHVXOWLQFRUURVLRQDQGGHSRVLWV7KH\FDQDOVROHDGWRWKHIRUPDWLRQRIIRDPDQGRUFRDWLQJV
WKDWVKRXOGEHPLQLPLVHG7KH72&FRQWHQW7RWDO2UJDQLF&DUERQVKRXOGDOVREHNHSWWRDPLQLPXP
:KHQXVLQJGHPLQHUDOLVHGZDWHUZLWKPL[HGEHGTXDOLW\/)—6FPDSKRVSKDWHLQMHFWLRQLVQRWUHTXLUHG$VDQDOWHUQDWLYHDQ$97
RSHUDWLRQFRQGLWLRQLQJZLWKYRODWLOHDONDOLVLQJDJHQWVIHHGZDWHUS+YDOXH싩DQGERLOHUZDWHUS+YDOXH싩PD\EHXVHG,QVXFKFDVHV
WKHFRQGXFWLYLW\GRZQVWUHDPRIDVHYHUHO\DFLGLFFDWLRQH[FKDQJHUPXVWEH—6FP
%DVHOHYHODGMXVWPHQWRIWKHS+YDOXHWKURXJKLQMHFWLRQRI1D32DGGLWLRQDO1D2+LQMHFWLRQRQO\LIWKHS+YDOXHLV
:LWKVXSHUKHDWHUVRIWKHVSHFLILHGXSSHUYDOXHVKRXOGEHWUHDWHGDVPD[LPXPYDOXH
,ISKRVSKDWHLVXVHGKLJKHU32FRQFHQWUDWLRQVDUHSHUPLVVLEOHVXEMHFWWRFRQVLGHUDWLRQRIDOORWKHUYDOXHVHJZLWKEDODQFHGRUFRRUGLQDWHG
SKRVSKDWHWUHDWPHQW6HHVHFWLRQ³&RQGLWLRQLQJ´
WATER QUALITY FOR STEAM BOILER SYSTEMS
5822 454 GB
3HUPLVVRSHUDWLQJSUHV
VXUH
General requirements
pH value at 25 °C
Acid capacity (KS 8.2)
Conductivity at 25 °C
Phosphate (PO4)
298/299
Technical guide – Water quality for steam boiler systems (continuation)
Note
The addition of phosphate is recommended, but not always essential.
Conversion: 1 mol/m3 = 5.6 °dH; 1 °dH = 0.179 mol/m3; 1 mval/kg = 2.8 °dH
Operation with salt-free boiler feedwater is also possible as an alternative to operation with saline boiler feedwater.
Maximum permissible direct boiler water conductivity as a function of pressure
Feedwater conductivity > 30 ˩S/cm
'LUHFWFRQGXFWLYLW\LQw6FP
2SHUDWLQJSUHVVXUHLQEDU
Figure 1
Maximum permissible silicic acid content (SiO2) of the boiler water as a function of pressure
B
6LOLFLFDFLGFRQWHQW6L2LQPJO
A
B
B
B
2SHUDWLQJSUHVVXUHLQEDU
Figure 2
A
This level of alkalinity is no longer permissible > 20 bar
KS 8.2 value in mmol/l
5811 454
B
Water quality for steam boiler systems
3
G.1 Appendices
Technical guide – Water quality for steam boiler systems (continuation)
Conditioning
Certain feedwater and boiler water properties must be improved by
means of chemical treatment.
This conditioning can contribute to:
ŶSupporting the formation of magnetic layers or other protective
oxide layers,
Ŷ5HGXFLQJFRUURVLRQE\RSWLPLVLQJWKHS+YDOXH
ŶStabilising the hardness and preventing or minimising boiler scale
and deposits,
Ŷ Achieving chemical bonding of residual oxygen
Conventional conditioning agents may, for example, contain sodium
and potassium hydroxide, sodium phosphate, sodium sulphite,
ammonia and diamide.
Note
Use of some of these chemicals may be restricted in certain
countries or processes.
General information regarding conditioning
ŶConductivity
– Saline
This refers to feedwater with an electrical conductivity of
> 30 μS/cm (e.g. downstream from a softening system).
– Low-salt
This refers to feedwater with an electrical conductivity of
0.2 - 30 μS/cm (e.g. downstream from a T.D.S. system).
– Salt-free
This refers to feedwater with an electrical conductivity of
< 0.2 μS/cm and a silicic acid concentration < 0.02 mg/l , as well
as condensate with an electrical conductivity of < 5 μS/cm (e.g.
downstream from full T.D.S. systems with mixed bed quality).
ŶAcid capacity KS 4.3
Elevated alkalinity (m value) in raw/soft water implies too much
bonded carbon dioxide. This results in an increased alkalinisation of
the boiler water, which in turn leads to an increased risk of corrosion
in the steam boiler and also in the steam network downstream from
the boiler due to separation of vapour-volatile carbon dioxide.
ŶSetting the alkalinity
The selection of the alkalising agent depends, amongst other
things, on the use of the steam, the steam pressure and the type
of water treatment. There are solid and volatile alkalising agents.
Balanced conditioning with phosphate or its derivatives can also be
ŶOxygen and carbon dioxide or oxygen binders
Carbon dioxide and oxygen are expelled from the feedwater by
total thermal deaeration. Should it prove to be impossible to keep
the oxygen content of the feedwater below the permissible values
in practical operation, e.g. due to repeated idle periods, then the
use of oxygen binders is necessary. This "correction chemical" is
admixed to the feedwater via the dosing equipment.
Note
Note
Evaporation of the boiler water leads to concentration of the solute
non-volatile boiler constituents in the remaining boiler water (salts,
solid conditioning agents). This is referred to as "thickening" of the
boiler water. Such conditions can lead to local alkali concentrations
that result in stress fracture corrosion. Therefore, with only mildly
buffered feedwater (feedwater with low salt content) with a
conductivity of < 30 μS/cm, sodium hydroxide is only permissible
as an alkalising agent if the recommended pH range cannot be
achieved with sodium phosphate alone. At the same time, low
pH value.
organic conditioning agents have also been in use for years.
If organic conditioning agents are used, the amounts and processes
the supplier of the chemical products.
Deviation during conditioning
If actual values deviate during continuous operation from those
The chemical composition of the boiler water can be monitored
Ŷ,QDGHTXDWHWUHDWPHQWRIWKHWRSXSZDWHU
blow-down of a part of the water volume. This must be carried out
in such a way that both solute and suspended contaminants can be
eliminated.
Ŷ Advanced corrosion of certain system components
ŶContamination of the water due to ingress of contaminants from
other systems, e.g. condensate tank, heat exchangers.
Appropriate changes must be carried out immediately to reinstate
correct operation. For example, returned condensate must not affect
the feedwater quality and may have to be treated.
Conditioning/Warranty
Note
The warranty becomes void:
5811 454
ŶLIGRVLQJDJHQWVDUHXVHGWKDWDUHQRWOLVWHGLQWKHJXLGHOLQHVRUKDYHQRWEHHQDJUHHGZLWK9iessmann.
4
Water
quality
for steam
boiler systems 300/301
Technical guide – Water quality for steam boiler systems (continuation)
Sampling
Sampling of water and steam from the boiler system must be
conducted in compliance with ISO 5667-1; the treatment and
handling of samples in compliance with ISO 5667-3.
Samples are taken by means of a sampling cooler. This cools
down the water sample to a temperature of approx. 25 °C.
In order to take a usable sample, the sampling line must be
flushed for an appropriate period.
The sample should be analysed immediately after it has been
taken, since values may change as a result of prolonged settling.
Opaque or contaminated sample water must be filtered prior to
testing.
See also "Sampling cooler operating instructions"
Sampling points
Provision must be made for sampling points at representative
locations in the system.
Typical sampling points are:
ŶBoiler feedwater inlet valve
ŶBoiler water from a downpipe or a continuous T.D.S. line
ŶTop-up water downstream from the top-up water treatment
system or the storage tanks
ŶCondensate at the outlet from the condensate tank, if installed
Otherwise, the sample must be taken from as close as
possible to the feedwater tank.
Analysis
General information
Verification of compliance with the values specified in Table 1
(page 2) and Table 2 (page 2) must be provided by means of
analysis.
If the analyses are conducted according to other standards or by
means of indirect methods, those methods must be calibrated.
A clean work surface with water supply and drainage must be
available for carrying out the analyses. The required equipment
must also be stored at this workplace in a cabinet.
Note
For some types of water, the amount of solute matter can be
estimated based on its conductivity. Furthermore, a correlation
exists between the pH value and both conductivities.
For continuous monitoring of the O2 and pH values as well
as water hardness, Viessmann supplies water analysis
components.
Analysis method/Test equipment
Boiler values can be measured adequately with the test
equipment during ongoing boiler operation. In the event of
severe deviation in values, the actual values must be confirmed
by means of the corresponding standardised analysis methods
and corrective measures identified.
Parameters must be checked in accordance with the following
standards:
Acid capacity
Conductivity
Copper
Iron
Oxygen
pH value
Phosphate
Potassium
Silicic acid*6
EN ISO 9963-1
ISO 7888
ISO 8288
ISO 6332
ISO 5814
ISO 10523
ISO 6878–1
ISO 9964–2
Sodium
TOC*7
Total harness as Ca + Mg
ISO 9964–1
ISO 8245
ISO 6059
The acid conductivity in the form of the hydrogen ion
concentration must be measured continuously in the same
way as the conductivity in hydrogen form, after the sample
has passed through a severely acidic cation exchanger with a
volume of 1.5 l.
The exchanger is inserted into a cylinder with a diameter:
height ratio of 1:3 or less, whereby the exchanger medium takes
up at least three quarters of the cylinder volume.
The ion exchanger must be regenerated once it has been
exhausted by two thirds ; this can be recognised when using an
exchanger with colour indicator and transparent cylinder.
Shutdown periods/frost protection
5811 454
If boiler systems are shut down for longer periods, it is
recommended that the systems are completely filled with water
and that the water is enriched with oxygen binders to bind the
oxygen in the water. The boiler must be kept under pressure for
this purpose.
Another option is that of dry preservation, which is
recommended for shutdown periods exceeding 4 weeks.
For detailed relevant information, see manual "Preservation on
the water & hot gas side"
*6 There is currently no European or international standard; see for example DIN 38405-21 Standardised German procedure for water, waste water and
sludge examination; anions (group D); photometric determination of dissolved silicic acid (D 21).
*7 As an alternative, the permanganate index can be measured in accordance with ISO 8467, if these values are specified.
Water quality for steam boiler systems
5
G.1 Appendices
[A 4] Sketch of steam boiler container system
302/303
Container system with Vitomax 200-HS 2.9 t/h, 10 bar
RT-Group LLC Ukraine
G.2 Technical data collection and tables
[Tb. 1.0] SI units / conversion table
Pressures
bar
mbar
mm WC
1 kp/cm2 = 1 at
1
1000
10200
1.02
750
0.001
1
10.20
0.00102
0.750
0.0000981
0.0981
1
0.0001
0.07355
0.981
981
10000
1
735.5
1 torr
0.001333
1.333
13.6
0.00136
1
1 Pa
0.00001
0.01
0.1020
0.000012
0.0075
1 bar
1 mbar
1 mm WC
1 kp/cm2
torr
Energy, work, heat
kcal
Mcal
1 kcal
1
0.001
1 Mcal
1000
1
0.000239
0.000000239
1
1 kJ
0.2388
0.000239
1 MJ
238.8
0.2388
860
0.860
3600000
1 J = 1 Ws
1 kWh
J Ws
kJ
MJ
kWh
4186.8
4.1868
0.00418
0.001163
4186800
4186.8
4.1868
1.163
0.001
0.000001
0.0000002778
1000
1
0.001
0.0002778
1000000
1000
1
0.2778
3600
3.6
1
Output and heat flux
kcal
kcal/min
1 kcal/h
1
1 kcal/min
60
1 J/s = 1 W
1 kW
J/s W
kW
MJ/h
0.01667
1.163
0.001163
0.0041868
1
69.768
0.69768
0.2512
0.860
0.01433
1
0.001
0.0036
860
0.01433
1
0.001
0.0036
Temperature
°C degrees Celsius
°C degrees Fahrenheit
°C degrees Kelvin
°C degrees Rankine
°C
°F
K
°R
1
1.8 x °C + 32
°C + 273
1.8 x °C + 492
0.56 x (°F - 32)
1
0.56 x °F - 460
°F + 460
K - 273
1.8 x K - 460
1
1.8 K
0.56 x (°R - 492)
°R - 460
0.56 x °R
1
„The conversion values are rounded
„Kelvin - Temperature on the absolute temperature scale,
whereby 1 degree Kelvin = 1 degree Celsius
„Rankine - Temperature on the absolute temperature scale,
whereby 1 degree Rankine = 1 degree Fahrenheit
„Temperature differential in Celsius division: 1 in gr.
„Temperature differential in Fahrenheit division: t in degF.
304/305
[Tb. 1.1] 1. Conversion table - BTU / BHP / KW / t/h
1. Conversion table - BTU / BHP / KW / t/h [Tb. 1.1]
kCal/hr
kW
BTU
BHP
t/ha)
562,500
675
2,250,000
68
1
1.5
841,667
1,010
3,366,667
101
1,125,000
1,350
4,500,000
135
2
1,395,833
1,675
5,583,333
168
2.5
1,687,500
2,025
6,750,000
203
3
1,970,833
2,365
7,883,333
237
3.5
2,250,000
2,700
9,000,000
270
4
2,812,500
3,375
11,250,000
338
5
3,375,000
4,050
13,500,000
405
6
3,937,500
4,725
15,750,000
473
7
4,500,000
5,400
18,000,000
540
8
5,062,500
6,075
20,250,000
608
9
5,625,000
6,750
22,500,000
675
10
6,750,000
8,100
27,000,000
810
12
7,875,000
9,450
31,500,000
945
14
a)
12 bar, 102 °C feedwater
temperature.
G.2 Technical data collection and tables
[Tb. 2.0] Steam table (saturation state)
Absolute
pressure
Temp.
Specific
volume,
boiling water
Q’
m3/kg
Steam
volume
Q”
3
m /kg
Steam
density
U”
kg/m3
Water
enthalpy
K¶
kJ/kg
K´
kJ/kg
U
kJ/kg
Steam
enthalpy
Evaporation
heat
S
bar
ts
°C
0.010
0.015
0.020
0.025
0.030
0.035
6.98
13.04
17.51
21.10
24.10
26.69
0.0010001
0.0010006
0.0010012
0.0010020
0.0010027
0.0010033
129.20
87.98
67.01
54.26
45.67
39.48
0.00774
0.01137
0.01492
0.01843
0.02190
0.02533
29.34
54.71
73.46
88.45
101.00
111.85
2514.4
2525.5
2533.6
2540.2
2545.6
2550.4
2485.0
2470.7
2460.2
2451.7
2444.6
2438.5
0.040
0.045
0.050
0.055
0.060
0.065
28.98
31.04
32.90
34.61
36.18
37.65
0.0010040
0.0010046
0.0010052
0.0010058
0.0010064
0.0010069
34.80
31.14
28.19
25.77
23.74
22.02
0.02873
0.03211
0.03547
0.03880
0.04212
0.04542
121.41
129.99
137.77
144.91
151.50
157.64
2554.5
2558.2
2561.6
2564.7
2567.5
2570.2
2433.1
2428.2
2423.8
2419.8
2416.0
2412.5
0.070
0.075
0.080
0.085
0.090
0.095
39.03
40.32
41.53
42.69
43.79
44.83
0.0010074
0.0010079
0.0010084
0.0010089
0.0010094
0.0010098
20.53
19.24
18.10
17.10
16.20
15.40
0.04871
0.05198
0.05523
0.05848
0.06171
0.06493
163.38
168.77
173.86
178.69
183.28
187.65
2572.6
2574.9
2577.1
2579.2
2581.1
2583.0
2409.2
2406.2
2403.2
2400.5
2397.9
2395.3
0.10
0.15
0.20
0.25
0.30
0.40
45.83
54.00
60.09
64.99
69.12
75.89
0.0010102
0.0010140
0.0010172
0.0010199
0.0010223
0.0010265
14.67
10.02
7.650
6.204
5.229
3.993
0.06814
0.09977
0.1307
0.1612
0.1912
0.2504
191.83
225.97
251.45
271.99
289.30
317.65
2584.8
2599.2
2609.9
2618.3
2625.4
2636.9
2392.9
2373.2
2358.4
2346.4
2336.1
2319.2
0.45
0.50
0.55
0.60
0.65
0.70
78.74
81.35
83.74
85.95
88.02
89.96
0.0010284
0.0010301
0.0010317
0.0010333
0.0010347
0.0010361
3.576
3.240
2.964
2.732
2.535
2.365
0.2796
0.3086
0.3374
0.3661
0.3945
0.4229
329.64
340.56
350.61
359.93
368.62
376.77
2641.7
2646.0
2649.9
2653.6
2656.9
2660.1
2312.0
2305.4
2299.3
2293.6
2288.3
2283.3
0.75
0.80
0.85
0.90
0.95
1.00
91.79
93.51
95.15
96.71
98.20
99.63
0.0010375
0.0010387
0.0010400
0.0010412
0.0010423
0.0010434
2.217
2.087
1.972
1.869
1.777
1.694
0.4511
0.4792
0.5071
0.5350
0.5627
0.5904
384.45
391.72
398.63
405.21
411.49
417.51
2663.0
2665.8
2668.4
2670.9
2673.2
2675.4
2278.6
2274.0
2269.8
2265.6
2261.7
2257.9
306/307
[Tb. 2.1] Steam table (saturation state)
Absolute
pressure
Temp.
Specific
volume,
boiling water
Q’
m3/kg
Steam
volume
Q”
3
m /kg
Steam table (saturation state) [Tb. 2.0]
Steam
density
U”
kg/m3
Water
enthalpy
Steam
enthalpy
Evaporation
heat
K¶
kJ/kg
K´
kJ/kg
U
kJ/kg
467.13
504.70
535.34
561.43
584.27
604.67
2693.4
2706.3
2716.4
2724.7
2731.6
2737.6
2226.2
2201.6
2181.0
2163.2
2147.4
2133.0
2.417
2.669
2.920
3.170
3.419
3.667
623.16
640.12
655.78
670.42
684.12
697.06
2742.9
2747.5
2751.7
2755.5
2758.8
2762.0
2119.7
2107.4
2095.9
2085.0
2074.0
2064.9
0.2554
0.2403
0.2268
0.2148
0.2040
0.1943
3.915
4.162
4.409
4.655
4.901
5.147
709.29
720.94
732.02
742.64
752.81
762.61
2764.8
2767.5
2769.9
2772.1
2774.2
2776.2
2055.5
2046.5
2037.9
2029.5
2021.4
2013.6
0.0011331
0.0011386
0.0011438
0.0011489
0.0011539
0.0011586
0.1747
0.1632
0.1511
0.1407
0.1317
0.1237
5.637
6.127
6.617
7.106
7.596
8.085
781.13
798.43
814.70
830.08
844.67
858.56
2779.7
2782.7
2785.4
2787.8
2789.9
2791.7
1998.5
1984.3
1970.7
1957.7
1945.2
1933.2
204.31
207.11
209.80
212.37
214.85
217.24
0.0011633
0.0011678
0.0011723
0.0011766
0.0011809
0.0011850
0.1166
0.1103
0.1047
0.09954
0.09489
0.09065
8.575
9.065
9.555
10.05
10.54
11.03
871.84
884.58
896.81
908.59
919.96
930.95
2793.4
2794.8
2796.1
2797.2
2798.2
2799.1
1921.5
1910.3
1899.3
1886.6
1878.2
1868.1
219.55
221.78
223.94
226.04
228.07
230.05
0.0011892
0.0011932
0.0011972
0.0012011
0.0012050
0.0012088
0.08677
0.08320
0.07991
0.07686
0.07402
0.07139
11.52
12.02
12.51
13.01
13.51
14.01
941.60
951.93
961.96
971.72
981.22
990.48
2799.8
2800.4
2800.9
2801.4
2801.7
2802.0
1858.2
1848.5
1839.0
1829.6
1820.5
1811.5
S
bar
ts
°C
1.5
2.0
2.5
3.0
3.5
4.0
111.37
120.23
127.43
133.54
138.87
143.62
0.0010530
0.0010608
0.0010675
0.0010735
0.0010789
0.0010839
1.159
0.8854
0.7184
0.6056
0.5240
0.4622
0.8628
1.129
1.392
1.651
1.908
2.163
4.5
5.0
5.5
6.0
6.5
7.0
147.92
151.84
155.46
158.84
161.99
164.96
0.0010885
0.0010928
–
0.0011009
–
0.0011082
0.4138
0.3747
0.3426
0.3155
0.2925
0.2727
7.5
8.0
8.5
9.0
9.5
10.0
167.75
170.41
172.94
175.36
177.66
179.88
–
0.0011150
–
0.0011213
–
0.0011274
11
12
13
14
15
16
184.07
187.96
191.61
195.04
198.29
201.37
17
18
19
20
21
22
23
24
25
26
27
28
G.2 Technical data collection and tables
[Tb. 2.0] Steam table (saturation state)
Absolute Temp.
pressure
Specific
volume,
boiling water
Steam
volume
Steam
density
Water
enthalpy
Steam Evaporation
enthalpy
heat
308/309
[Tb. 2.1] Properties of superheated steam
3UHVVXUH
S
EDU
Properties of superheated steam [Tb. 2.1]
6SHFLILFHQWKDOS\LQN-NJDWDVWHDPWHPSHUDWXUHLQƒ&
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
G.2 Technical data collection and tables
[Tb. 2.1] Properties of superheated steam
6SHFLILFHQWKDOS\LQN-NJDWDVWHDPWHPSHUDWXUHLQƒ& 3UHVVXUH
S
EDU
±
±
±
310/311
Properties of superheated steam [Tb. 2.1]
3UHVVXUH
S
EDU
6SHFLILFYROXPHLQPNJDWDVWHDPWHPSHUDWXUHLQƒ&
±
–
±
–
±
±
±
±
–
±
–
±
±
±
±
–
±
±
–
±
–
±
±
–
±
±
±
±
±
±
–
±
±
–
±
±
±
±
–
±
–
±
±
±
±
–
±
±
–
±
–
±
±
–
±
±
–
±
–
±
±
±
±
–
±
±
–
±
–
±
–
–
±
±
±
±
±
–
±
±
–
±
±
–
±
±
±
±
±
±
–
±
–
±
±
–
±
±
±
±
±
±
–
±
–
±
±
–
±
±
±
±
±
±
–
±
±
±
–
±
±
±
±
±
±
–
±
±
±
±
±
±
±
–
±
±
±
±
–
±
G.2 Technical data collection and tables
[Tb. 2.1] Properties of superheated steam
6SHFLILFYROXPHLQPNJDWDVWHDPWHPSHUDWXUHLQƒ&
–
±
±
3UHVVXUH
S
EDU
312/313
[Tb. 2.2] Properties of saturated steam
Properties of saturated steam [Tb. 2.2]
Properties of saturated steam
Saturated steam
Absolute pressure
Specific thermal capacity
temperature ts [°C]
p [bar]
Cp [kJ/kgK]
Dynamic viscosity
106 x ǹ [kg/ms]
100
1.01
2.135
11.968
110
1.43
2.177
12.459
120
1.98
2.207
12.851
130
2.69
2.257
13.243
140
3.62
2.315
13.538
150
4.76
2.395
13.930
160
6.18
2.479
14.323
170
7.93
2.583
14.715
180
10.04
2.709
15.107
190
12.56
2.856
15.598
200
15.56
3.023
15.990
210
19.10
3.199
16.383
220
23.21
3.408
16.873
230
27.97
3.634
17.364
240
33.49
3.881
17.756
250
39.79
4.158
18.247
260
46.96
4.468
18.835
270
55.07
4.815
19.326
280
64.22
5.234
19.914
290
74.48
5.694
20.601
300
85.94
6.281
21.288
Specific thermal capacity and dynamic viscosity of saturated steam as a function
of saturated steam temperature (ts)
Notes:
„ Absolute pressure = operating pressure + 1 [bar]
„ Conversion factor kJ/kg to kWh/kg
1 kJ/kg = 1/3600 kWh/kg
„ Density
(p) = for:
Kinematic viscosity 1
Specific volume (Ŷ)
„ For: Kinematic viscosity (v) =
[kg/m2]
Dynamic viscosity (ǹ)
Density (S)
[m2/s]
G.2 Technical data collection and tables
[Tb. 2.3] Enthalpy/Entropy
4000
2 ,0
3 ,0
2,6
2,2
5
4
10
20
30
26
22
40
100
50
700°C
3800
C
0°
400
600
500
3600
600
220
30
260 0
200
70
500
500
r
3400
100
0ba
400
400
3200
300
3000
200
20
0
3,
4
5
40
10
0
50
2800
3
26 0
22
200
10
enthalpi kJ/kg
300
0
,
6
2, 2,2 2
100
0
1,
5
0, 0,4
2600
3
0,
2
0,
1
0,
05 4
0, 0,0 ,03
0
2400
2
0,0
x =1
1
0,0
0,95
0,90
2200
r
0,85
ba
08
61
0
0
,0,
C
0°
0,80
2000
0,
70
h-s diagram
0,7
5
-1
-1
entropi kJ kg K
314/315
Internal pipe roughness [Tb. 3.0]
Internal pipe roughness k in mm for various pipes and pipe materials
Pipes
Absolute
Material
Description
Condition
Copper
Drawn or pressed
New
roughness k
in mm
Brass
(also steel pipes
Bronze
with specified
Alloys
material coating
0.0013 ÷ 0.0015
Glass
Rubber
Pressure hose
New
0.002
not embrittled
Plastic
Steel
New
0.0015 ÷ 0.0070
Seamless
New
0.02 ÷ 0.06
(commercially available)
- Rolling skin
0.03 ÷ 0.04
- Pickled
0.07 ÷ 0.10
- Galvanised
Longitudinally seam-welded
New
0.04 ÷ 0.10
- Rolling skin
0.01 ÷ 0.05
- Tarred
0.008
- Galvanised
Seamless and longitudinally
Used
seam-welded
- Moderately
0.1 ÷ 0.2
rusted
or lightly
encrusted
Cast iron
New
0.2 ÷ 0.6
- With casting skin
0.1 ÷ 0.2
- Tarred
Asbestos cement
Used
0.5 ÷ 1.5
New
0.03 ÷ 0.1
New
0.1 ÷ 0.2
- Carefully smoothed
0.3 ÷ 0.8
- Sleek
1÷2
- Medium rough
2÷3
(e.g. Eternit)
Concrete
- Rough
Pipe friction factor˨ as a function of Re and relative roughness di/k.
G.2 Technical data collection and tables
[Tb. 3.1] Pipe friction factor / Reynolds number
316/317
Pressure drop in steam pipes [Tb. 4.0]
Fittings and profiles
:
C=]
Pipes: C = O l/d with O = 0.0206 acc. to Eberle 'p in Pa
For given pipework components of the same nominal diameter, the flow resistance
coefficients C are determined from Fig. 4. From the total of all individual values 6 C
and the operating data, the total pressure drop 'p in bar results from Fig. 5.
pe
Pi
w
k
or
0
10
m
valve
ough
aight-thr
r
t
s
d
r
a
d
n
Sta
l
Ang
ev
e
alv
Pressure drop value C
Tee
pipe
Sp
ec
ial
v
comp
ensator
alv
e
.
.
.
.
Corr
ugat
ed
.
Bend
.
.
ff
ut-o
e
gat
Sh
.
Fig. 4
Source: GESTRA
e
valv
Nominal diameter DN
G.2 Technical data collection and tables
[Tb. 4.1] Pressure drop in steam pipes – example
Example:
Pipework sections DN 50
20 m pipe
C = 8.11
1 angle valve
C = 3.32
2 special valves
C = 5.60
1 tee
C = 3.10
2 pipe bends 90°
C = 1.00
C = 21.10
Operating data:
Temperature
Steam pressure
Speed
t = 300 °C
p = 16 bar
w = 40 m/s
Result
p = 1.1 bar
Absolute
pressure p
Speed w
.
.
Temperature
.
Flow resistance coefficient C
.
.
.
.
.
.
.
.
Fig. 80
Source: GESTRA
Pressure drop
.
318/319
[Tb. 9.0] Strömungsgeschwindigkeiten (Richtwerte)
Conversion for the units of water hardness [Tb. 5]
Conversion for the units of water hardness
ºdH
ºe
ºTH
ppm
mMol/l
Deutsche Grad
1º dH=
1
1,253
1,78
17,8
0,179
Englische Grad
1º e=
0,798
1
1,43
14,3
0,142
Französische Grad
1º TH=
0,560
0,702
1
10
0,1
CaCo3 (USA)
1º ppm=
0,056
0,07
0,1
1
0,01
mMol/l
1º mMol/l=
5,6
7,02
10,00
100,0
1
%
Source: Spirax Sarco
kg re-evaporation steam per 100 kg condensate or re-evaporation in %
1
2
3
4
6
8
10
15
20
30
40
50
60
50
0.1
p2=
60
0.2
0.1
70
0.4
0.2
80
100
1
0.4 0.5
90
0.7
0.3
P2 = Pressure of condensate and
re-evaporation steam after expansion
(in bar abs)
2
1.5
3
2
4
5
3
4
0.1
10
5 6 7 8 9 10
140
160
180
All specified pressures in bar
Condensate temperature before expansion (in °C)
120
Pressure before expansion (in bar abs)
1
p 2=
200
20
15
1
220
20
240
40
30
260
70
70
350
200
˚C
bar (abs)
100 bar (abs)
100 bar (abs)
100
280 300
40 50
10
G.2 Technical data collection and tables
[Tb. 6] Re-evaporation on condensate expansion
Steam pressure (bar absolute)
1.1
1.2
1.3
1.4
1.6
1.8
2
3
4
6
8
10
15
20
30
40
60
80
100
4
10
15
8 10
20
20
30
40
40
70
50
100
200
80
100
500
150
120
700 1.000
250
200
2.000 3.000
350
5.000
10.000
25
10
13.6
Nominal diameter DN
Internal diameter mm
15
17.3
60
20
22.3
500
300
25
28.5
32
37.2
40
43.1
50
54.5
65
70.3
80
82.5
107
100
Steam throughput (in kg/h) (at 25 m/s steam velocity)
300
400
Internal diameter of seamless steel pipes according to EN 10220 "ISO TUBES" in standard wall thickness
6
132
125
20.000
150
159
207
200
50.000
260
250
100.000
Steam pressure
Saturated steam
throughput
Ergebnis
Next larger DN
Example
310
300
200.000
340
350
500.000
550 kg/h
50 mm
DN 50 (54.5 mm)
5 barO (6 bar abs.)
389
400
1.000.000
320/321
Pipe cross section for given steam parameters - example [Tb. 7]
[Tb. 7] Pipe cross
section for given
steam parameters
(example)
G.2 Technical data collection and tables
[Tb. 8] Pressure drop in water pipes for a particular flow rate - example
Flow resistance head Hv in m for 100 m straight pipe run
Water flow rate
.
.
.
.
.
w
Flo
cit
lo
ve
.
yW
0.4
/s
m
.
.
.
.
.
.
Fig. 6
Source: GESTRA
Nominal diameter DN
322/323
[Tb. 9.0] Flow velocities (standard values)
Flow velocities (standard values) [Tb. 9]
Standard values for flow velocity (w):
Type of pipe
Pressure range P (bar)
Flow velocity w (m/s)
Steam pipes:
Wet steam
≤ 10
10 - 20
Saturated steam
≤1
10 - 15
> 1 to ≤ 5
15 - 25
> 5 to ≤ 10
25 - 35
> 10 to ≤ 40
35 - 40
> 40 to ≤ 100
40 to ≤ 60
Superheated steam: as for saturated steam, but with selection of the respective "higher" velocity
Safety valve discharge pipes and start-up pipe
Against atmospheric
(also mixing cooler air vent pipe)a)
pressure
≤ 70
Exhaust vapour and waste steam pipes, expansion steam
Against atmospheric
in condensate pipes (open vented system)
pressure
Long-distance steam lines
< 40
≤ 20
Suction line
≥ 0.5 to ≤ 1
10 - 25
Water pipes:
Condensate pipes
Feedwater pipes
Pressure line
≥ 1 to ≤ 3
Suction line
≥ 0.5 to ≤ 1
Pressure line
Boiler alkali and blow-down pipe
≥ 2 to ≤ 3.5
≥ 1 to ≤ 2
(without expansion steam)
Boiler alkali and blow-down pipe
≤1
10 - 15
(with expansion steam)
> 1 to ≤ 5
15 - 20
DHW and service water pipes
Cooling water
≥ 1 to ≤ 2
Suction line
Pressure line
Compressed air pipes
Natural gas pipes
Fuel oil pipes
Combustion air ducts
Flue ducts
≥ 0.5 to ≤ 1.5
≥ 1.0 to ≤ 3.5
≥ 10 to ≤ 20
Up to ≤ 0,05
≥ 3 to ≤ 8
> 0.05 to ≤ 1
≥ 5 to ≤ 10
> 1 to ≤ 6
> 10 to ≤ 25
Suction line
≥ 0.2 to ≤ 1
Pressure line
≥ 0.5 to ≤ 1.5
Suction line
≥ 8 to ≤ 20
Pressure line
≥ 15 to ≤ 30
Up to chimney connection
≥ 8 to ≤ 15
G.2 Technical data collection and tables
[Tb. 10] Steam boiler inspection checklist
Operation of steam boiler systems
Part I - General instructions for operators of steam boiler systems
For category IV steam boilers
June 1983 edition (unchanged 8/93)
TRD 601 OperationAppendix 1, /
EN 12953 T6, Appendix C
(see also Section 18.3)
S
3.2.2
Water level - display equipment
F
F*
F*
F*
12 months
6 months
Safety valves**
Month
3.2.1
Week
Operation, maintenance and inspection tasks per:
24h / 72h
BosB
See
Section
TRD 601
Sheet 2
Checklist for a steam boiler system (steam and hot water boiler)
(S = Visual inspection, monitoring for unusual noises; F = Function test)
Type of tests (examples)
Venting
Blow through and for boilers with p < 32 bar
3.2.3
Remote water levels
S
Comparison of display with directly
indicated water level
3.2.4
Filling/sampling facility
F
Functionality and continuity
3.2.5
Water level controller
S
3.2.6
Water level limiter
3.2.7
Flow limiter
3.2.9/12
Temperature or pressure controller
S
F*
3.2.10/13
Temperature or pressure limiter
S
F*
F*
Blow through and functionality
F*
Blow through or reduction to switching point
Flow reduction
3.2.8/11
Temperature or pressure indicators (pressure gauges)
S
3.2.14
Drain and T.D.S. equipment
F
3.2.15
Boiler - fittings/valves
S
3.3.1
Feedwater and circulation equipment
S
Carry out comparative test
Change in set value/test keys
Checking with precision thermometer /
zero-point check
F*
By activation
By activation
F
By alternate operation
By analytical monitoring in accordance
with TRD 611
3.3.2
Feedwater and boiler water examination
X
3.3.3
Devices for monitoring boiler water for ingress of contaminants
S
3.4.1
Flue gas damper limit switch
F*
Closing and re-opening of the damper
3.4.2
Burner control (servomotors for air and fuel)
F*
Functionality
3.4.3
Combustion air fan, ignition and/or cooling air fan
F*
Quiet operation, power transmission (e.g. V-belt)
3.4.4
Air pressure volume display and air pressure limiter
3.4.5
Fuel shut-off facility
S
3.4.6
Fuel tank and lines/valves
S
3.4.7
Fuel pressure display
S
F
3.4.8
Safety shut-off facility upstream of the burner
(for 72-hour operation also in the return line)
S
F
3.4.9
Tightness checking facility or intermediate ventilation
S
F
3.4.10
Burner limit switch
3.4.11
Emergency stop switch
3.4.12
Ignition
S
03/04/2013
Ventilation
S
3.4.14
Flame monitor
S
3.4.15
Assessment of combustion
S
3.4.16
Assessment of combustion chambers and hot gas flues
3.4.17
Emergency stop switch
F
S
Activation of test key
F* Interruption of the pulse line
F
Functionality
Functionality, tightness
Functionality, tightness
Pivoting the burner, pulling the burner lance
F
F*
Activation
F*
F
By covering the sensor
F*
F
F* - during the six-monthly inspection (according to TRD or EN 12953 Part 6 Appendix C).
** A regular check for easy action of the safety valves is required at least every 6 months in systems with fully demineralised water and in hot water generators.
The interval should not exceed 4 weeks for other types of steam boiler.
324/325
Literature references
(L1)
(L2)
(L3)
(L4)
- TRD Technical Regulations for Steam Boilers, 2002 edition
- Boiler Operating Manual / 11th edition, Publishing house: Dr. Ingo Resch, 2005
- Steam boiler legislation / Pressure Equipment Directive - 97/23/EC, 2004
- Thermodynamic Calculations for Combustion and Steam Boiler Systems, Friedrich & Karl Nüber,
R. Oldenburg Munich, 1967
(L5) - Heating Notebook, Air Conditioning, R. Oldenburg Munich, 1995
(L6) - Technical Manual for Water Treatment Systems, Publishing house: Technik Berlin, 1968
(L7) - Centrifugal Pumps and Centrifugal Pump Systems, Vogel Buchverlag, 1994
(L7.1) - Pipe Technology, Vogel Buchverlag, 1993
(L8) - Examples and Exercises: Chemical Processing Technology, Publishing house for the primary
materials industry, Leipzig 1963
(L9) - VDI Heat Atlas, VDI Verlag, 1994
(L10) - Heat manual, Resch Verlag, 1991
(L11) - Gestra Guide, Bremen, 2005
(L12) - Codes of Practice - Spirax/Sarco
Keyword index
277
125
19
Acoustic emissions
Acoustic emissions from monoblock / duoblock burners
Application areas
254
32
226
Basic requirements and regulations for the licensing procedure
Boiler equipment
Boiler lye and blow-down lines
58
132
240
49
122
242
118
48
93
21
142
64
224
73
160
66
297
86
305
Chemical water treatment (CWT)
Chemical water treatment system (CWT softening system)
Chimney connection and design
Combustion air
Combustion air, supply air ducts
Common flue system, merging of flue gas flows
Combustion systems
Combustion system
Component layout
Components of a steam boiler system
Condensate management
Condensate management / treatment
Condensate pipes and systems
Condensate pumps
Condensate pumps - criteria for sizing and operation
Condensate treatment
Contact protection insulation
Control system
Conversion table - BTU / BHP / KW / t/h
51
Dual fuel burner
44
279
106
105
75, 171
229
Economiser (ECO)
Earthquake protection
ECO output
Economiser (ECO) operation
Exhaust vapour condenser
Exhaust vapour, waste steam and discharge pipes
76, 174
151
76
Feedwater cooler
Feed pumps - criteria for design and operation
Feedwater preheater
326/327
71
227
104
321
80, 236
232
136
143
Feedwater pumps & control
Feedwater - softened water - drinking water
Flame tube temperature monitoring (FTTM)
Flow velocities (standard values)
Fuel system
Fuel lines
Function description - reverse osmosis system (RO)
Function description of open vented condensate systems
144
Function description of sealed unvented condensate systems
50
Gaseous fuels
65
12
High pressure condensate
History of steam generation
287
273
273
84
244
314
83
82, 244
83, 248
9
Inspection intervals for boilers according to the Pressure Equipment Directive
Installation of category III land-based steam boilers (TRD 802)
Installation of category IV land-based steam boilers
Insulation of pipes, tanks etc.
Internal electrical system demand
Internal pipe roughness
Internal power demand
Internal system demand
Internal thermal power demand
Introduction
324
Keyword index
88
254
49
323
65
Legal framework
Licensing procedure according to Section 13 of the [German] Health & Safety at Work Act
Liquid fuels
Literature references
Low pressure condensate
87
75, 163
38
Main functions
Mixing cooler
Multi-boiler system
219
Notes on design engineering of selected pipework systems
283
284
59
265
268
271
Operation
Operating modes
Osmosis systems
Overview of German licensing procedures
Overviews and summary of application documents and their compilation
Overviews for compiling the application documents
130
196
319
315
182, 183
78
237
317
316
320
116
272
334
102
313
309
85
70, 150
Partial deaeration system
Pipework calculations and sizing
Pipe cross section for given steam parameters - example
Pipe friction factor / Reynolds number
Pipework
Pipework system
Planning and design information for connection pieces
Pressure drop in steam pipes - example
Pressure drop in steam pipes
Pressure drop in water pipes for a particular flow rate - example
Pressure / heat maintenance - steam boiler
Principle requirements and regulations for the installation of steam boilers
Production
Product range
Properties of saturated steam
Properties of superheated steam
Protection against the formation of condensate
Pumps
253
88
Requirements and regulations
Rules and regulations
67, 180
304
98
239
162
302
188
294
286
24, 26, 103
Sampling cooler
SI units / conversion table
Selection of the boiler pressure level
Sizing the flue system
Sizing the thermal equipment
Sketch of steam boiler container system
Specifications - materials, welding work
Standard circuit diagram
Standards and regulations governing operation
Steam boilers
328/329
41
322
96
274
219
46
306
307
Steam boiler in standby mode
Steam boiler inspection checklist
Steam boiler selection
Steam boiler system installation room
Steam pipes / steam distributors
Steam superheaters (SH)
Steam table (saturation state)
Steam table (saturation state)
210
113
74
Strength, expansion, support spans, clearances, routing / mountings
Superheater (SH) operation
System-dependent thermal equipment
168
75
293
298
18
85
296
60
129
278
T.D.S. expander
T.D.S. expander and lye cooler
Technical data collection and tables
Technical Guide on water quality - extract
Thermal capacity
Thermal insulation
Thermal insulation of pipes
Thermal water treatment (TWT)
Total deaeration system
Transportation and handling
11
110
Utilising steam
Utilising condensing technology
119
Variable-speed combustion air fan
42, 99
233
139
54, 128
16
15
52
Waste heat boilers
Waste water and floor drainage systems
Water analysis, general explanations
Water treatment
Wet steam, saturated steam, superheated steam
What is steam?
Wood combustion
The comprehensive range of products and services
from Viessmann
Oil low temperature and
Gas low temperature and
Solar thermal and
condensing technology
condensing technology
photovoltaics
13 – 20,000 kW
4 – 20,000 kW
Detached houses
Apartment buildings
Commerce / Industry
Local heating
networks
Individual solutions with efficient systems
The comprehensive range of products and
services from Viessmann
The comprehensive range of products and
services from Viessmann offers individual
solutions with efficient systems for all
applications and all energy sources. As
environmental pioneers, the company has,
for decades, been supplying particularly
efficient and clean heating systems for oil
and gas, as well as solar thermal systems
along with heat generators for sustainable
fuels and heat pumps.
The comprehensive range of products
and services from Viessmann offers top
technology and sets new benchmarks.
With its high energy efficiency, this range
helps to save heating costs and is always the
right choice where ecology is concerned.
Individual and efficient
Viessmann offers the right heating system for
any demand – wall mounted or floorstanding,
in individual combinations – all are futureproof
and economical. And whether for detached
houses or two-family homes, large residential
buildings, commercial/industrial use or for
local heating networks; for modernising
existing properties or new build – they are
always the right choice.
330/331
Wood combustion technology,
Heat pumps for
CHP and biogas production
brine, water and air
4 – 13,000 kW
1.5 – 2000 kW
Air conditioning technology
System components
The comprehensive range of products and services from
Viessmann: Individual solutions with efficient systems for all
energy sources and applications
Key performers
The Viessmann Group sets the technological
pace for the heating industry. This is what the
Viessmann name represents, and also what
the names of the subsidiaries in the Group
represent, as they are founded on the same
pioneering spirit and power of innovation.
The company offers the following:
„Condensing technology for oil and gas
„Solar thermal systems
„Heat pumps
„Wood combustion systems
„CHP modules
„Biogas plants
„Services
Viessmann is extremely highly specialised in
all these market segments, yet at the same
time the company has a crucial advantage over
specialist suppliers: Viessmann understands
heating technology as a systematic whole and
offers unbiased advice on technology and fuel
type. This guarantees the best solution for
every application.
The comprehensive range of products and services
from Viessmann
Detached houses
Apartment buildings
Commerce / Industry
Local heating networks
Architect's own home, Bad Füssing,
Residential development Zi Wei
Ameco A380 Hangar Beijing,
European Parliament, Strasbourg,
Germany
Garden Xi'an, China
China
France
Detached house, Kevelaer,
"Wohnoase" residential park in
Porsche Leipzig,
European Parliament, Brussels,
Germany
Regensburg, Germany
Germany
Belgium
Heliotrop Freiburg,
HafenCity Hamburg,
City of Tomorrow, Malmö,
The Palm Jumeirah,
Germany
Germany
Sweden
Dubai
Detached house, Wiesloch,
Hotel Lagorai Cavalese,
Congressional Centre, Brunstad,
Monastery St. Ottilien,
Germany
Italy
Norway
Germany
Loftcube Regional Garden Show,
Studio flats, Brandenburg,
University library, Bamberg, Germany
Residential estate, Pfäffikon,
Neu-Ulm, Germany
Germany
Oil low temperature and
condensing technology
13 – 20,000 kW
Gas low temperature and
condensing technology
4 – 20,000 kW
Solar thermal and
photovoltaics
Wood combustion
technology,
CHP and biogas
production
4 – 13,000 kW
Heat pumps for
brine, water and air
1.5 – 2,000 kW
The comprehensive range of products and services from Viessmann:
Individual solutions with efficient systems for all energy sources and applications
Switzerland
332/333
Futureproof heating technology for
all requirements
Energy consumption worldwide has doubled
since 1970 and will triple by 2030. The
result: The fossil fuels, oil and gas, are
dwindling, energy prices are on the rise and
excessive CO2 emissions continue to affect
our environment. Energy efficiency is a must if
we want our future to be secure.
In these projects, Viessmann again and
again faces up to the most varied challenges
to supply efficient heating technology by
offering innovative solutions – in historical
listed buildings as well as in modern industrial
complexes or in the large-scale residential and
industrial arena.
In almost every industrial nation, supplying
heat to residential and commercial buildings
accounts for the largest share of energy
consumption – consequently it also offers the
greatest savings potential. Advanced efficient
heating systems from Viessmann are in use
around the world, not only in many private
households, but also in numerous major
international projects, where they make a
sizeable contribution to the efficient use of
energy resources.
City of Tomorrow, Malmö, Sweden
The company
334/335
Viessmann – climate of innovation
The Viessmann brand promise concisely
expresses all that we hope to achieve. It is
our key brand message and, together with
our brand label, is an identifying feature
throughout the world. "Climate of innovation"
is a promise on three levels: It is a commitment
to a culture of innovation. It is a promise of
high product utilisation and, at the same time,
an obligation to protect the environment.
Comprehensive range of products and
services for all fuel types
Viessmann is one of the leading international
manufacturers of heating systems and, with
its comprehensive range of products and
services, offers individual solutions in the
shape of efficient systems for all applications
and types of fuel. As an environmental
pioneer, the company has been supplying
particularly efficient and clean heating
systems.
Acting in a sustainable manner
For Viessmann, to take responsibility, means
a commitment to act in a sustainable way.
This means bringing ecology, economy and
social responsibility into harmony with each
other, ensuring that current needs are
satisfied without limiting the basis for life
for the generations to come.
Efficiency Plus
With the sustainability project "Efficiency Plus"
Viessmann shows at its Allendorf site, that
the political goals set for 2020 with regard to
climate and energy can already be achieved
today with commercially available technology.
This project demonstrates:
„Environmental protection
„Efficiency with resources
„Securing manufacturing sites for the future
Viessmann won the German
Sustainability Award 2009 for its
commitment to climate protection
and efficient use of resources.
As a result, fossil fuels have been cut by
40 percent and CO2 emissions reduced by
a third.
For the particularly efficient
utilisation of energy through the
innovative heat recovery centre at
the company's main site in Allendorf/
Eder, Viessmann was rewarded with
the Energy Efficiency Award 2010.
Viessmann Werke GmbH & Co. KG
Company details
„Established in: 1917
„Employees: 9000
„Group turnover: €1.7 billion
„Export share: 50 percent
„1
6 factories in Germany, France, Canada,
Poland, Hungary, Austria, Switzerland
and China
„Sales organisation in 37 countries
„120 sales offices worldwide
„3 service providers
Performance spectrum
„Condensing technology for oil and gas
„Solar thermal systems
„Heat pumps
„Wood combustion systems
„CHP modules
„Biogas plants
„Services
Imprint
Technical Guide for steam boilers
Publisher
Viessmann Werke, Allendorf (Eder)
Author
Gerd Sattler
Tilman Schibel
Editing & Design
agentur mp2 GmbH, Melsungen
Overall production
Grafisches Centrum Cuno, Calbe (Saale)
© 2011 Viessmann Werke
Sources
Unless otherwise specified, all graphics and
photographs are from Viessmann.
p 12
p 13
p 14
p 16
p 18
p 54
Stiftung Deutsches Technikmuseum,
Photo: Tilman Schibel
BLS-Energieplan Berlin
Silvia Schibel
Tilman Schibel
Co. Fissler
Peter Kuhlmann
336/337
G.1 Appendix
[A 1]
G.1 Appendix
[A 1]
G.1 Appendix
[A 1]
G.1 Appendix
[A 1]
5470 700 GB 03/2011
Copyright Viessmann.
Duplication and alternative use only with prior written consent.
Subject to technical modifications.
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement