MA GISTER UPPSA TS

MA GISTER UPPSA TS
Magisterprogram Energiingenjör 240 hp
MAGISTERUPPSATS
Environmental and economic implications of a
conversion to natural gas
Simon Bengtsson
Magisteruppsats 15hp
Avesta 2013-08-20
Abstract
The concern Outokumpu Stainless has for some time been investigating the possibility to
convert some of their operations from oil and LPG to liquefied natural gas. This is due to
several advantages, such as better fuel price per effective energy value, lower carbon
emissions, safety benefits etc.
This study presents a possible conversion of an integrated steel plant called Avesta Works.
The plant is a part of the Outokumpu Stainless group and produces, processes and casts
stainless steel.
A feasibility study has earlier been made and in addition to that study, it has been requested
that a deeper analysis of the burners should be made and to analyze the possible environmental, energy and economic benefits of a conversion to LNG. I have chosen to present the
financial result by calculating a price per MWh which the liquefied natural gas should cost to
provide a payback time in less than five years.
The burner installations at Avesta Works are relatively efficient. The largest are equipped
with some type of technology that take advantage of the heat in the flue gases. The largest
energy savings that could be made in connection with a conversion is to install efficient
burners.
The fuels that would be converted to liquefied natural gas are WRD oil and LPG at about 20
different installations. The main difference between LNG, LPG and oil from an environmental
point of view is its low carbon, dust, sulfur and potential low
emissions (mostly dependent on the chosen burner technique). From an economic standpoint, liquid natural gas is the
preferred fuel as how the market looks today (2012). But the investment needed to convert
to natural gas in Avesta is large, requiring that the fuel cost and other advantages have to be
highly advantageous to be beneficial.
The results from this project show that a conversion to liquid natural gas results in a higher
energy use and cost to vaporize LNG instead of LPG. However, there will be a reduction of
energy use at line 76. Carbon dioxide emissions from the existing installations will decrease
by approximately 18 %. Sulfur dioxide and dust emissions will be reduced to zero and a small
reduction of
is estimated. Purchase of oxygen will increase with a conversion; however,
a smaller amount of ammonia should be needed for cleaning the exhaust gases. Old and
worn out equipment will not be needed at L76 which will reduce maintenance costs.
HÖGSKOLAN I HALMSTAD • Box 823 • 301 18 Halmstad • www.hh.se
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
To sum up, the cost of liquefied natural gas has to be less than about 400 SEK/MWh to give a
payback period of five years. When inspecting the prices at the LNG market today (2012),
this price can be achieved, which means that an investment in liquefied natural gas at Avesta
could be of interest.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Sammanfattning
Koncernen Outokumpu Stainless har sedan en tid tillbaka tittat på att eventuellt konvertera
flera av deras anläggningar från olja och gasol till flytande naturgas. Detta beror på flera fördelar, t.ex. bättre bränslepris per effektivt energivärde, lägre utsläpp av emissioner, säkerhetsfördelar m.m.
Denna uppsats behandlar en eventuell konvertering i ett integrerat stålverk med namnet
Avesta Works. Anläggningen är en del av Outokumpu Stainless och producerar, behandlar
och valsar rostfritt stål.
En förstudie har tidigare genomförts, dock efterfrågades en djupare analys av brännarna
samt en analys av de potentiella miljö-, energi- och ekonomifördelar vid en eventuell konvertering till flytande naturgas. För att redovisa det ekonomiska resultat har jag valt att beräkna
fram ett pris/MWh som den flytande naturgasen får kosta för att ge en återbetalningstid
(pay-off) på fem år.
Brännarinstallationerna i på Avesta Works är relativt effektiva. De flesta är utrustade med
någon typ av teknik för att ta tillvara på värmen i rökgaserna. Den största energibesparing
som skulle kunna göras i samband med en konvertering är att installera effektiva brännare.
De bränslen som skulle konverteras till flytande naturgas är WRD-olja och gasol vid cirka 20
olika installationer. Den största skillnaden mellan flytande naturgas, gasol och olja från en
miljösynpunkt är dess låga koldioxid-, stoft-, svavel- och potentiella låga
-utsläpp. Ur en
ekonomisk synpunkt är flytande naturgas att föredra som marknaden ser ut idag (2012).
Investeringen som krävs för att konvertera till naturgas i Avesta är dock stor, vilket kräver att
bränslets kostnad och andra fördelar måste vara väldigt fördelaktiga.
Resultatet från detta projekt visar att en konvertering till flytande naturgas ger en ökad
energiförbrukning och kostnad för att förånga flytande naturgas istället för gasol. Dock förväntas en reducering av energianvändningen vid linje 76. Koldioxidutsläppen från de nuvarande installationerna kommer minska med cirka 18 %. Svaveldioxid och stoft kommer att
reduceras till noll och en liten reducering av
är antagen. Inköp av syre kommer att öka
med en konvertering dock finns en potential för att mindre mängd ammoniak kommer att
behövas för rening av avgaser. Gammal och utsliten utrustningen kommer inte behövas på
L76 vilket kommer reducera underhållskostnader.
Sammanfattningsvis behöver kostnaden för flytande naturgas vara under cirka 400
SEK/MWh för att ge en återbetalningstid på fem år. Enligt marknaden idag (2012) kan detta
pris uppnås vilket betyder att en investering i flytande naturgas kan vara intressant.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Nomenclature
APL
Annealing and Pickling line
HRM
Hot Rolling Mill
MS
Melt Shop
EAF
Electric Arc Furnace
WBF
Walking Beam Furnace
L76
Line 76
OEC
Oxygen-Enhanced Combustion
SNCR
Selective non catalytic reduction
SCR
Selective catalytic reduction
LPG
Liquefied Petroleum Gas
WRD-Oil
Wide Range Distillate Oil
LNG
Liquefied Natural Gas
N
Normal cubic meter
V
Volume
M
Molar mass
Methane
Ethane
Propane
Butane
CO
Carbon Monoxide
Carbon Dioxide
Ammonia
Nitrogen Dioxide
Nitrogen Dioxides
Oxygen
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Sulfur Dioxide
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Contents
Preface ....................................................................................................................................... 8
1
2
3
Introduction ....................................................................................................................... 9
1.1
Problem formulation ................................................................................................... 9
1.2
Purpose ........................................................................................................................ 9
1.3
Limitations ................................................................................................................... 9
Method ............................................................................................................................. 10
2.1
Literature studies ....................................................................................................... 10
2.2
Analysis ...................................................................................................................... 10
Avesta Works – The process .......................................................................................... 11
3.1
3.1.1
Furnaces and burners ......................................................................................... 12
3.1.2
Production of steel ............................................................................................. 13
3.1.3
Energy use .......................................................................................................... 13
3.2
Hot Rolling Mill .......................................................................................................... 13
3.2.1
Furnaces and burners ......................................................................................... 13
3.2.2
Production of steel ............................................................................................. 14
3.2.3
Energy use .......................................................................................................... 14
3.3
4
Melt Shop................................................................................................................... 12
Annealing and Pickling Line ....................................................................................... 14
3.3.1
Furnaces and burners ......................................................................................... 14
3.3.2
Production of steel ............................................................................................. 15
3.3.3
Energy use .......................................................................................................... 15
Industrial burners – a background to understand the installations at Avesta Works
16
4.1
High-Velocity Burners ................................................................................................ 17
4.2
Regenerative Burners ................................................................................................ 19
4.3
Oxygen-enhanced burners ........................................................................................ 20
4.3.1
Air enrichment burner........................................................................................ 21
4.3.2
Oxygen lancing burner ....................................................................................... 21
4.3.3
Oxy/Fuel ............................................................................................................. 22
4.3.4
Air-Oxy/Fuel ....................................................................................................... 24
4.4
Flameless Burners ...................................................................................................... 24
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
5
6
The burner installations at Avesta Works .................................................................... 26
5.1
Melt shop ................................................................................................................... 26
5.2
Hot Rolling Mill .......................................................................................................... 26
5.3
Annealing and pickling line ........................................................................................ 27
Fuel environmental, energy and economic differences................................................ 29
6.1
6.1.1
Energy value and emissions ............................................................................... 30
6.1.2
Price for oil ......................................................................................................... 30
6.2
Energy value and emissions ............................................................................... 32
6.2.2
Price for LNG....................................................................................................... 32
Liquefied petroleum gas (LPG) .................................................................................. 33
6.3.1
Energy value and emissions ............................................................................... 34
6.3.2
Price for LPG ....................................................................................................... 34
6.4
Comparison between LPG, Fuel Oil and LNG ............................................................ 34
6.4.1
Energy value ....................................................................................................... 34
6.4.2
Emissions ............................................................................................................ 35
6.4.3
Fuel costs ............................................................................................................ 36
6.4.4
Heat transfer ...................................................................................................... 36
Results .............................................................................................................................. 38
7.1
8
Natural Gas ................................................................................................................ 31
6.2.1
6.3
7
Fuel Oil ....................................................................................................................... 29
Energy analysis .......................................................................................................... 38
7.1.1
Energy use for steam production ....................................................................... 38
7.1.2
District heating use............................................................................................. 39
7.2
Emission analysis ....................................................................................................... 40
7.3
Economy analysis ....................................................................................................... 40
7.3.1
Oxygen costs....................................................................................................... 41
7.3.2
Ammonia costs ................................................................................................... 44
7.3.3
Maintenance costs ............................................................................................. 45
7.3.4
Carbon dioxide emission costs ........................................................................... 46
7.3.5
Energy costs........................................................................................................ 46
7.3.6
Economic summary ............................................................................................ 47
Other similar investments .............................................................................................. 48
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
9
8.1
SEMAB Stenugnsund ................................................................................................. 48
8.2
Uddeholms AB Hagfors .............................................................................................. 48
Conclusion ....................................................................................................................... 50
References ............................................................................................................................... 52
Literature .............................................................................................................................. 52
Websites ............................................................................................................................... 52
Contact persons .................................................................................................................... 54
Attachments ............................................................................................................................ 56
Attachment 1 – Combustion theory ..................................................................................... 56
Attachment 2 – Oxygen and flue gas calculations................................................................ 58
Attachment 3 – Energy use and emissions of the burner installations today ....................... 0
Attachment 4 – Energy use and emissions of the burner installations following a
conversion to LNG .................................................................................................................. 0
Attachment 5 – District heating calculations ......................................................................... 0
Attachment 6 – Economy calculation ..................................................................................... 1
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Preface
This report presents a Swedish D-thesis carried out for Outokumpu Stainless, Avesta Works.
The thesis is made in cooperation with the university of Halmstad, economy and technical
section. A D-thesis is required for examination of the program “Magisterprogram energiteknik, förnybar energi” which is an extension (of one year) of the energy engineering
program (bachelor).
The project was done as an investigation of the energy, environment and economy
implications of a possible conversion from LPG and oil to liquefied natural gas at Avesta
Works. A feasibility study has earlier been made which needs to be complemented with a
deeper investigation of the energy and environment implications. This thesis is a reference
document to the feasibility study.
I would like to show gratitude to my supervisor at the University of Halmstad Henrik Gadd
and my supervisor at Avesta Works Erland Nydén for inspiration, discussions and more. I
would also like to thank all the employees at Avesta Works for answering questions and
supporting this project.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
1 Introduction
1.1 Problem formulation
The constant pressure for change in the energy market today is making its toll on the energy
intensive industry. The increasing prices of fossil fuels, pressure of energy savings and
emission limitations are forcing energy intensive industries to reevaluate their energy system and become more energy efficient.
A conversion from liquefied petroleum gas (LPG) and fuel oil to liquefied natural gas (LNG)
would give several benefits to both the pressure of reducing emissions and to the economy
in general of the company. A feasibility study has been made with the purpose of giving an
overview of the investment, technical adaptation and environmental profit.
This study is going to go deeper into the energy, environmental and economy profit from a
potential investment by analyzing the installations at Avesta Works and the fuels being used.
1.2 Purpose
The purpose of this study is to investigate the processes at Avesta Works and compare LNG
to the fuels being used from energy, environmental and economic point of view in case of an
investment in LNG. Energy, environmental and economy calculations for the investment before and after the possible conversion are essential for the project. The economy calculation
will result in a price per effective energy for LNG that is needed to receive a “pay-off time” of
five years for the investment.
1.3 Limitations
This study is only going to include the installations at Avesta Works that is using liquefied
petroleum gas and WRD-oil.
The technical adaption for the conversation to natural gas won’t be a part of this study,
mostly due to that the burner techniques isn’t chosen yet. However, a technical description
of different burners and the burners used today will be a part of this study.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
2 Method
2.1 Literature studies
An extensive literature study has been made about burners, energy and combustion technique, fuel properties and more. The larger part of the information has been from literature.
2.2 Analysis
Parameters and data have been gained from company reports, follow-ups and contacts.
Prices used in this report are approximated or estimated to protect company information.
To get a better understanding of the burner installations and identify possible environmental
and economic implications, interviews with Avesta Works personnel have been very important for the analysis. That’s because of the large amount of different installations and the
limited timespan for this project.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
3 Avesta Works – The process
Avesta Works is a part of a global Finnish company called Outokumpu. Outokumpu is working with both hot bands, cold band rolls and plates of stainless steel and are one of the leading companies in the stainless steel market today.
In 1883, the company Avesta Jernverks AB was formed in a little town called Avesta. In the
beginning, Avesta works where producing iron until 1924 when Avesta started to produce
steel. Over the years the company has transformed under various owners (Avesta AB, Avesta
Sheffield and Avesta Polarit) with Outokumpu acquiring all the shares in the year 2001.
Avesta Works have three main processes on site. These processes are Melt Shop, Hot Rolling
Mill and Annealing and Pickling Line. Avesta Works is fully integrated, which means that all
the steps from scraps and raw material to rolled coil could be done at the site. Although not
all of the steel goes through all the processes at Avesta Works, some are transported to
other steel treating sites from the chain of processes at Avesta [24]. An overview of the
process at Avesta Works is illustrated in figure 3.1.
Steel Mill
•This is where scraps are melted, carbon and sulfer are reduced
and varies metals are added (for the specific steel code).
Continues Casting
•In Continues casting the steel are cut into slabs and the
dimension is being determined. After continues casting the steel
could go through hot and/or cold grinding.
Hot Rolling Mill
•In the hot rolling mill the steel first gets reheated by a walking
beam furnace to further procced to the steckel mill where the
slabs are rolled thinner. After the process the "black bands"
could be sold or go through the annealing and pickling line.
Annealing and Pickling Line
•In the annealing and pickling line the bands are rolled even
thinner and processed for better surface properties.
Figure 3.1: Illustration of the process at Avesta Works
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
3.1 Melt Shop
The Melt Shop (MS) is the first process where the combination of internal and external
scraps and raw materials are being melted into slabs. The first part of the Melt Shop is where
the scraps are lifted into baskets. These baskets are preheated by the flue gases from the
electric arc furnace (EAF) to prevent steam explosions from ice and to lower the energy use
of the electric arc furnace.
The EAF is the large consumer of electric energy at the site. In the year of 2012, the EAF used
over 150 GWh of electric energy and has a maximum electric power demand of 90 MW. The
scrap is melted by “electric arcs” that are created between three electrode tips and the
scrap. Every charge that is being melted weight around 100 tons.
From the EAF the melted steel, with a temperature of 1650 degrees Celsius, is tapped into
preheated ladle. From the ladle the melted steel is transported to a converter. In the converter, the carbon of the steel is reduced from around 1 % to the amount that is desired by
the product. To reduce the carbon from the steel, oxygen is being used to oxidize the carbon
of the steel. When the oxidization is done, the chrome content is needed to increase. This is
done by re-reducing chrome from the slag with silica and aluminum substances. The final
stage in the converter is where the sulfur is reduced by adding fluorspar and dehydrated
lime.
The next part of the process is the ladle furnace. In the ladle furnace final adjustments can
be made to the steel before it is being turned into slabs. Temperature is being regulated and
alloy substances can be added if required. After the ladle furnace, the steel is transported to
continues casting and is then leaving the steel mill.
At the process of continues casting, the steel dimensions is being determined. The melt is
being fed into a casting box, which is preheated. From there the melt is fed into a watercooled chill whose actual measurement decides the dimensions of the steel. Through the
process the steels surface is being cooled by water. Then, the steel is cut into slabs.
After the process of continues casting, the slabs could go through hot grind and cold grinding. At the site there are two heavy grinding machines and two fine grinding machines that
counts as hot grinders. These work with the temperature of around 800 degrees Celsius.
After the hot grinding the slabs could be processed through the three cold grinding machines
that operate outside the range of the hot grinding machines [24].
3.1.1 Furnaces and burners
At the Melt Shop there are 12 different burner installations with the combine maximum
power of 34.7 MW. Six of the burner installations are connected to the steel mill and the
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
other six is connected to continues casting. The absolute largest of these installations is the
burner at EAF and it has its maximum power capacity of 15.8 MW [25].
3.1.2 Production of steel
The production of steel is greatly connected to the amount of effective energy use and the
amount of actual energy use. The production of steel from the Melt Shop in the year of 2012
were approximately 347 000 tons of slabs, which could be compared to 750 000 tons which
is the maximum permitted amount of steel production by the Melt Shop [26].
3.1.3 Energy use
The energy use at the Melt Shop the year of 2012 were approximately 250 GWh of electricity, 39 GWh of LPG and 3 GWh of fuel oil (E01) [22] [26].
3.2 Hot Rolling Mill
The first part of the Hot Rolling Mill (HRM) is the two heating furnaces, walking beam
furnace (WBF) A and B. For the moment, only B is used and A is in standby in case of shutdowns. In WBF the slabs are reheated to make them possible to process. The outgoing temperature of the slabs is around 1200-1270 degrees Celsius. The flue gases from WBF B are
used for preheating in recuperatores and then used in a waste heat boiler for heat exchange
with the district heating network of Avesta. After the reheating in the walking beam furnaces, the slabs are transported to the roughing mill where they are rolled to a thickness around
20 mm.
After being rolled the slabs may be transported to the next process in HRM, the Steckel Mill.
Depending on the properties required of the steel product the slabs may pass several times
through the Steckel Mill. The slabs are hooked at one coiler on each side of the steckel,
thereafter the band run through it from both directions. Two coiler furnaces are keeping the
band warm through the Steckel Mill and the flue gases from them are used for preheating of
air. As a last step, the bands are being cooled with water. After this process the product is
called “black bands” and these could be sold as they are or continue being processed in the
Annealing and Pickling line [24].
3.2.1 Furnaces and burners
HRM contains four burner installations frequently being used and one (at WBF A) is used a
few weeks each year. The largest maximum power output comes from the burner installa-
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
tion at WBF B. Its max power capacity is 66 MW and is the single largest burner installation
at Avesta Works. The burner installation at WBF A has a max power capacity of 57 MW and
is only used when there is maintenance work at WBF B or at unplanned stops as a backup
[25].
3.2.2 Production of steel
The production of hot rolled steel where approximately 290 000 tons in 2012 [26]. This
amount could be compared to 1 200 000 tons which is the permitted amount of produced
hot rolled steel [6].
3.2.3 Energy use
The energy use at the Hot Rolling Mill the year of 2012 was approximately 41 GWh of
electricity and 186 GWh of LPG. The Hot Rolling Mill is the largest consumer of LPG at Avesta
Works. This is mostly because of the walking beam furnaces [22].
3.3 Annealing and Pickling Line
The Annealing and Pickling Line (APL) is where the “black bands” are rolled even thinner and
processed to get better surface properties. Bands are welded together and then annealed
and pickled in “Line 76” (L76). The furnace that provides heat for the pickling is heated by
WRD-oil. The bands temperatures are about 1200 degrees Celsius after the pickling and
thereafter they get cooled by water and air. This heating and cooling process is required to
get the right mechanical properties of the steel.
There is a chance that a metal oxide shell could form on the bands during the annealing. It is
then needed to remove this through breaking the shells and blast the band to further clean
it.
If the bands still need to get thinner or receive more properties they could go through the
cold rolling mill called “Z-high” and then through L76 again [24].
3.3.1 Furnaces and burners
APL contains, because of the acid regeneration plant, four burner installations. Three of
them are in the acid regeneration plant and the forth is at L76. The installation with the most
power output is at L76 which has a maximum power capacity of 39 MW. The burner
installation in L76 uses WRD-oil as fuel and the burners at the acid regeneration plant are
using LPG [25].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
3.3.2 Production of steel
The production of steel products at the Annealing and Pickling Line (2012) was
approximately 174 000 tons in 2012 [26]. This could be compared to the permitted
production of 750 000 tons/year [6].
3.3.3 Energy use
The energy use at the Annealing and Pickling Line 2012 consisted of 45 GWh of electricity, 15
GWh of LPG and 100 GWh of fuel oil (WRD). The acid regeneration process falls under the
Annealing and Pickling Line which contributes with its LPG use. L76 is the only installation
using WRD-oil at Avesta Works and is the largest consumer of oil at Avesta Works [22].
Table 3.1: Shows an overview of the approximate production and energy use at Avesta Works 2012
Melt Shop
Hot Rolling Mill
LPG use [MWh]
37 920
172 500
Annealing and
Pickling line
15 400
WRD-Oil use
[MWh]
Steel production
[tons]
0
0
102 000
347 000
290 000
174 000
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
4 Industrial burners – a background to understand the installations at Avesta Works
There are a lot of different kinds of burners being used in industry today. The numerous
amount used for specific applications are all around in the society. They are the key component in industrial combustions processes. In this chapter, only burners and techniques used
in metal industry are considered. This chapter is supposed to give an overview of the most
common burners and combustion techniques used in the metal industry, give an understanding of the techniques being used at the different installations at Avesta Works and
identify possible improvements that could be made in collaboration with the conversion.
Because of metals having a high melting temperature, a high intensity burner is often required to acquire the right temperature in the metal. This includes, for example, oxygenenhanced combustion and air preheating to increase the flames temperature and thus be
able to melt the metal. These burners have the potential to produce a high amount of emissions so the design becomes important to reduce emissions [33].
In the metal industry, where batches of metals are used, some kind of transport vessel is
needed. These vessels are often required to pre-heat to reduce the stress of the materials
exposing to high temperature metals. This is often done by an industrial burner, as seen in
figure 4.1. An example of this type at Avesta Works is the ladles transporting the metal from
the electric arc furnace to the converter.
Figure 4.1: Illustration of a transportation vessel being preheated [33].
Another unique aspect to metals production may be the requirement to reheat the metals
for further processing (in our case, the walking beam furnace). This is because of the time
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
and/or distance between different processes. This may be economically efficient in some
ways, but with an environmental and energy point of view it’s very inefficient.
Commonly used burners in metal industry today, and thus at Avesta Works, includes highvelocity burners, regenerative burners, flameless burners, air-oxy/fuel burners, oxy/fuel
burners and combinations of the techniques [33]. These techniques are shortly explained
and discussed in chapter 4.1-4.4.
4.1 High-Velocity Burners
A high-velocity burner is defined by having a high exit velocity of the fuel from the burner.
The speed exceeds 90 m/s and is often in the 120-150 m/s. These kinds of burners have been
used extensively in metal and ceramic industry since the 1960s.
The oil high-velocity burners have only been using nozzle-mixing configurations meanwhile
gas burners use both premix and nozzle mix configuration of the fuel. This leads to more
available designs to construct the burner. Most high-velocity burners are gas fired, but there
are burners available for oil. Most of the burners are “dual-fuel” which means they have the
ability to fire with diesel oil and gas. When comparing high-velocity oil burners to gas, oil
burners have less turndown capability, aren’t reliable with direct spark ignition, have less
excess air capabilities and are prone to carbon formation if the air/fuel ratio isn’t maintained.
The high-velocity burners where mostly known for their uses in low-temperature processes
but have shown that they are equally useful in high temperature processes. The specific fuel
consumption is frequently enhanced over conventionally fired systems. Heating is often accomplished faster than conventional systems as well. In many cases, considering the economical and performance point of view, a few strategically placed high-velocity burners
could be equal or better than conventional low- to medium-velocity burners.
With high-velocity burners less excess air is needed, comparing to low- to medium-velocity
burners, because of the flame temperature from the burner is diluted faster by entrainment
of cooler products of combustion from the furnace. This leads to a lower air ratio (less excess
air is heated) which ultimately increases the efficiency of the combustion.
There are many kinds of high-velocity burners on the market today. The differences between
these are many, although the largest difference is how the high velocity is acquired. Some
examples of high-velocity burners are listed below [33].

Air-Staged Nozzle Mix High-Velocity Burner

ISO-Jet Burner
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp

Conventional Nozzle Mix Burner

Premix burners
Some benefits are listed in table 3.1.
Table 4.1: Shows a few benefits of high-velocity burners [34].
Benefits of High-Velocity Burners
1. Rapid and uniform heat distribution
2. Robust with high turndown and excess air capability
3. Good control of firing pattern through choice of outlet
4. Can cause fuel savings with hot air
The most wanted benefit of high-velocity burners is the ability to gain a high convective heat
transfer. With increasing convection, better temperature uniformity is gained in the fire
chamber. This could be profitable for product quality in metal industry.
The control system for combustion depends on which process that is considered. But to
properly utilize the burners jet properties, the heat input and fuel/air ratio should be chosen
to operate the burners at the maximum input rate for the longest possible time in any heating cycle. Most furnaces got multiple “control zones” where the temperature is measured.
These are then usually connected to the control system of the burners to provide the right
temperature all over the furnace.
All burners have some possibility to vary their maximum power demand. The amount of decreased power demand (fuel input) is often referred to as “turndown ratio”, which is defined
by the maximum fire rate divided by the lowest. With a high “turndown ratio” there is a
wider temperature range which the burners can operate. This gives the ability to lower the
temperature and fuel input in case of production stop.
All burners connected to a control zone must have means of fuel/air ratio control for an efficient combustion. One way to control the fuel/air ratio is by using electronics. But the most
used way to control fuel/air ratio is with the cross-connected ratio regulator. The function of
cross-connected ratio regulators is based on the principle that the internal air and gas orifices of a burner are fixed resistances to flow, such as the flow and pressure are related as seen
in the equation bellow.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
=
4.2 Regenerative Burners
The regenerative burner technique where first used in 1858. After the principle where
tested, it quickly became adapted in the metal industry for reheating of iron and steel and
for melting steel. From this principle, a furnace for melting steel where used based on the
technique for a long time until it got replaced by the electric arc furnace.
The principle of regenerative burners is connected to the flue gas losses. Because of flue
gases temperature being close to the temperature of the furnace, there is a great potential
to use these gases for fuel savings. The regenerative burners are using the flue gas to preheat the combustion air, using a regenerative medium, to decrease the fuel needed to provide the temperature of the furnace. The heat recovered this way could approach 90 % effectiveness, which gives considerable fuel savings. Because of the air and flue gas is in counter flow, the combustion air can almost reach the flue gas temperature (from the furnace)
when it is mixed with the fuel.
The two main components of a regenerative burner is the high-temperature preheated air
burner that can also work as an exhaust port, and the heat-storage-medium-containing regenerator. There are typically two types of regenerative burners, the generally smaller one
where the burner and regenerator share the same housing and the regenerator has a horizontal gas flow path, and the generally larger one where the burner share almost the same
look as the conventional hot air burner but is instead connected to a regenerator working
with vertical gas flow through the regenerative medium.
The most common used heat transfer medium in regenerative burners in 2003 is alumina
balls. The main reason for this is its high melting temperature and high corrosive tolerance.
When it comes to the controlling of regenerative burners, many experts agree that this kind
of burner is the most challenging one. The control system needs to live up to the requirements of safety and fuel/air ratio of conventional burners as to switch from “burner” to being a “flue” as often as twice a minute. When the burner is firing, between the switching
events, the temperature profile changes both for the firing and exhausting regenerators. The
big challenge for the control system is to maintain a correct fuel/air ratio and at the same
time maintain a balance between the firing rate and the exhaust extracted through the reversing regenerative cycle. To maintain the control of every variable, from the emissions to
optimize efficiency, a complex control system is needed.
With a functional regenerative burner, a low amount of
emissions is a fact. Because of
the effective use of the heat from the flue gases, a less amount of fuel is needed to provide
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
the same amount of heat as conventional burners. This leads to lower
emissions and
fuel savings. When talking about
-emissions, a high temperature in the combustion air
results in a high peak flame temperature which potentially leads to high
-emissions.
A good, often used, application for regenerative burners could be for reheating steel. Regenerative burners work at a high temperature and allow substantial fuel savings. In an existing furnace, the regenerative burners could be located at the unfired sections to increase
the production capabilities without the loss of efficiency.
4.3 Oxygen-enhanced burners
Historically, only air/fuel combustion technology has been used in almost all industrial
heating processes. This is partly because of the high cost of separating the oxygen from air.
In recent years, oxygen-enhanced heating processes have been increasing due to the decreasing cost of separating the oxygen.
The technique of increasing the oxygen content in the combustion air is called oxygenenhanced combustion (in short, OEC). This kind of technique is not used at Avesta Works.
Another way to enhance the combustion is by using pure oxygen. This kind of combustion is
called oxy/fuel.
Because combustion only needs a fuel and oxygen, the remaining nitrogen in air (79 %) is
unnecessary. By eliminating the nitrogen, many benefits could be acquired. Some benefits of
oxygen-enhanced combustion are listed in table 4.2.
Table 4.2: Lists some benefits that could be acquired by using oxygen-enhanced combustion [33]
Benefits of oxygen-enhanced combustion
1. Reduced pollutant emissions
2. Increased thermal efficiency
3. Increased processing rates
4. Reduced flue gas volumes
Oxygen-enhanced combustion is used by a wide range of industries with heating processes
today. The technique has mostly been used in high temperature processes that isn’t efficient
or where it’s not possible to use air/fuel. Most common reasons for using oxygen-enhanced
combustion in steel industry are productivity improvements and energy savings. Heating and
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
melting metal was one of the first applications of significant that used oxygen-enhanced
combustion.
4.3.1 Air enrichment burner
Oxygen has commonly been used to improve combustion in four ways; first way is by adding
oxygen into the incoming combustion air stream. The second way is by injecting oxygen into
an air/fuel flame. The third way is by completely replacing air by oxygen (oxy/fuel). The
fourth and final primary way is by separately providing air and oxygen to the burner.
An air enrichment burner is using oxygen to enrich the incoming air stream, as noted above.
To provide the right mixture, the oxygen is provided by a diffuser. This technology could often be adapted by conventional air/fuel burners. A schematic of how the burner works is
shown in figure 4.3.
Furnace wall
Air
Oxygen
Fuel
Figure 4.3: Schematic of an air enrichment burner [33]
4.3.2 Oxygen lancing burner
As with the air enrichment burner, this kind of technique is for low enrichment with oxygen.
However, there are a few advantages with this technique that could be of interest. Because
of the separate installation, there is no need to modify the burner itself. Also, there has been
evidence of lower
emissions using oxygen lancing compared to premixing. Oxygen lancing is a well-accepted method for
reduction. Because of the freedom of positioning the
injection, the flame shape can be varied by staging the combustion. The flame heat is generally more evenly spread by using this technique as well compared to pre-mixing.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
On the negative side, there is a higher cost for adding another hole to the chamber for the
lance. The loss contains of installation cost and productivity loss. However, the hole is typically very small, which minimize the disadvantage. Figure 4.4 shows a schematic of the oxygen lancing burner.
Air
Fuel
Figure 4.4: Schematic of an oxygen lancing burner [33]
4.3.3 Oxy/Fuel
An oxy/fuel burner, as shown in figure 4.5, uses pure oxygen for the combustion of the fuel.
When using pure oxygen, the temperature of the flame from the burner increases due to
nitrogen acts as a diluent that reduces the temperature. The flame temperature of different
fuels using air or oxygen for combustion is shown in table 4.3.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Table 4.3: Shows the different adiabatic flame temperature depending on air or pure oxygen
combustion [33]
Adiabatic flame temperatures for different fuels using air or oxygen for combustion
Air
Oxygen
2223 K
3053 K
2261 K
3095 K
2246 K
3100 K
Typically, the oxygen and the fuel are not pre-mixed because of the high reactivity of pure
oxygen, which could lead to explosions. They are most often not mixed until they reach the
outlet of the burner. This type of mixing is called “nozzle-mixing” and produces a diffusion
flame. A schematic of an oxy/fuel burner is shown in figure 4.5.
Oxy/fuel has the highest potential for improving a process, but it also might have the highest
operation cost. As earlier discussed, there are several benefits of using oxy/fuel burners.
These are shown in table 4.2.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Air
Fuel
Fuel
Oxygen
Oxygen
Figure 4.5: Schematic of oxy/fuel burner (left) and air-oxy/fuel burner (right) [33]
4.3.4 Air-Oxy/Fuel
The forth common method for oxygen enhanced combustion is when air and oxygen are
separately injected through the burner, often called air-oxy/fuel combustion. This technique
is a variation of the first three methods discussed. It typically got a higher potential of oxygen enhancement then air enrichment and oxygen lancing burners but lower than the
oxy/fuel technique.
There are several benefits of this technique. It still got the benefits of the oxy/fuel burners,
although in a reduced scale, but got a lower operation cost then oxy/fuel combustion. It is
needed to compare the increased benefits of oxy/fuel and its high operation cost to the
lower benefits value and operation cost of the air-oxy/fuel burner.
4.4 Flameless Burners
“The flameless burner” is a technique becoming more common in high temperature
installations today and is widely used at Avesta Works. The flameless combustion technique
uses a complex mixture of gas, combustion air (or oxygen) and recirculated flue gases to
maintain combustion without a flame. The technique has a “regenerative technique”. The
technology is named “FLOX” for “flameless oxidation”. The recuperative FLOX burners start-
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
ed developing in the early 1990s and the steel industry is one of the first industries that implemented the technique.
The FLOX burners use combustion gas and combustion air/oxygen unmixed at a high velocity
flow into the combustion chamber. The main differences from conventional burners are the
intense recirculation of exhaust gases in the combustion chamber, and the mixing with the
combustion air or oxygen. This, with the delayed mixing of air (or oxygen) and combustion
gases, prevents a flame front from forming. The flameless technique is mostly used in high
temperature operations; at least 800 degrees Celsius is needed to oxidize the fuel properly
in the combustion chamber.
The flameless burner technique is known for the low amount of produced
emissions.
Most
emissions are produced at the edge of the flame and with a “flameless”
combustion there is a possibility to reduce the emissions considerably. Another positive
aspect of this technique is the energy efficiency. With pre-heating of combustion air/oxygen,
fuel savings up to 50 % are possible compared to conventional technique [47].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
5 The burner installations at Avesta Works
In this chapter, I will identify the technique being used for combustion at Avesta Works.
Most of the smaller installations at Avesta Works use old conventional burner techniques
because of the low amount of energy use at these installations. However, almost all the
larger installations at Avesta Works use some kind of technique for making use of the heat in
the flue gases which makes a more efficient combustion and lower fuel costs.
5.1 Melt shop
In the melt shop, as earlier stated, there are 12 different LPG burner installations. Six of
these belong to the steel mill and the other six belongs to continues casting.
In the steel mill there are recently changed burners at the converter pre-heater. The new
burners installed are flameless high-velocity oxy-fuel burners. They use the flue gases and
the temperature of the vessel to pre-heat both the LPG and the oxygen used in the
combustion. The same type of burner is installed at the converter heater [48].
The burners installed at the EAF are conventional oxygen lancing burners [49]. Energy from
the flue gases is being used by preheating baskets bringing scraps to the EAF. The effectiveness of this choice compared to regenerative burners is uncertain. It can only be speculated
at this point because of it not being a part of this study. A combination might be a good
choice.
The rest of the burners in the steel mill are conventional non-regenerative air burners. These
include three ladle heaters. The energy being used at these installations are close to the
amount of the converter heater and pre-heater [48] [49].
All the burner installations at continues casting are conventional non-regenerative air
burners except for the cutting machines which uses conventional oxy/fuel burners. The
installations include two casting dryers, two casting pre-heaters and two cutting machines.
The energy use at these installations is, compared to the other installations at Avesta Works,
low. This explains the lack of regenerative technique due to the small amount of energy use
that could be reduced. High temperature processes that use large amount of energy have a
larger potential to reduce energy use compared to a smaller one (see figure 5.1).
5.2 Hot Rolling Mill
In the hot rolling mill there are five different LPG burner installations. These burners are
installed at the two coil furnaces, the two walking beam furnaces and a cutting machine
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
(cutting machine 3). WBF A wasn´t part of the conversion in the pre-study and is also excluded from this report.
The burner installation at WBF B consists of conventional air burners. However, as
mentioned in chapter 3.2, there are recuperators installed that exchanges heat with the
input combustion air through a heat exchanger. After the heat exchanger the flue gases,
with a temperature of about 300-400 degrees Celsius, are used for district heat production.
The burners installed at the two coil furnaces are recuperative, which is basically a burner
with a built in heat exchanger [33]. The flue gases exchange heat with either the combustion
air inside the burner, the fuel or both. Possible fuel savings from recuperative burner
technique is shown in figure 5.1.
Figure 5.1: Possible fuel savings from either regenerative or recuperative burners depending on gas
temperature [33]
Cutting machine 3, which is a part of the melt shop but it is located in the hot rolling mill,
have conventional burners and use oxygen for combustion as the other cutting machines.
5.3 Annealing and pickling line
At the annealing and pickling line there are six burner installations. Three installations are in
the annealing and pickling line and the others are at the acid regeneration plant.
The fuel being used at the annealing and pickling line (L76) is WRD-oil. There are three parts
of the installation; the two furnaces at the annealing and pickling process, the NOx reduction
installation (Kat-NOx) and a steam boiler. The NOx reduction process and the steam boiler
are small consumers when compared to the furnaces. Approximately 90 % of the oil is used
at the furnaces (2012).
The burners installed at the NOx reduction process are conventional air burners and have no
technique to make use of the flue gas energy. Conventional burners are also used at the
steam boiler.
The furnaces in L76 uses oxygen for combustion and the burners installed are flameless
oxygen fuel burners. Connected to these furnaces is an exhaust gas boiler that uses the energy of the exhaust gas to produce steam alongside a steam boiler. Both boilers are in bad
shape and there is a potential for efficiency’s. In case of a conversion, steam would no longer
be useful for atomizing oil. Instead, there is a potential to install a better exhaust gas boiler
to produce district heating or installing regenerative burners to even further reduce exhaust
gas temperature [50].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
The burner installations at the acid regeneration plant all use air for combustion. They are of
different brands but they use the same technique; high velocity conventional burners with
no capability for making use of the exhaust gas energy. The air used for combustion comes
from indoors and have an approximately temperature of 20 degrees Celsius [35].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
6 Fuel environmental, energy and economic differences
When investigating a different fuel, the most important factors to consider are the fuels
physical properties, emissions and costs (also the impact on products and burner installations of course, however that is not part of this thesis). In this chapter, a comparison will be
made between the fuels being used at Avesta works to the potential future fuel, liquefied
natural gas. The environment, energy and economic positives or negatives will be identified
by using emission factors given by authorizing authority, except for NOx emissions. NOx
emissions are too strongly connected to the chosen burner techniques that it can’t be evaluated by only looking at the fuel properties.
6.1 Fuel Oil
Oil is the most used energy source in the world. To use oil in the best way it is needed to
refine it. When you refine oil you separate it to heavy and light oils. The light oils are used
mostly as fuel for cars (petrol and diesel) and the heavy oil is mostly used for shipping and
power plants [15].
The future of oil is uncertain because of the decreasing amount of easy accessible oil and the
instability of oil producing regions. Not to mention the heavy environmental causes of incineration of the fuel. Because of oil being the dominating energy source under postwar times
(1950 to 1970) there where huge ramifications when the first “oil crisis” struck. It changed
the development of oil radically in Sweden, and most of the households started to change
heating systems from oil to electricity [16].
Because of there being no oil assets in Sweden, there are only import of crude oil and oil
products. The same refinery’s that is refining LPG is refining oil, one in Lysekil and two in
Gothenburg. There are several ports in Sweden that is receiving oil products. For example
the port in Gävle has a storage capacity of 950 000
in 140 different cisterns. From the
port, oil is distributed by train or lorry [19] [20].
Avesta Works uses oil mostly for process heating and comfort heating. WRD-oil is only used
for process heating meanwhile E01-oil is used mainly for comfort heating (E01-oil is excluded
from this study because of low consumption).
The oil cistern is located at L76 where district heating is keeping the oil at the required temperature of 35 degrees Celsius. In case of a conversion, the oil cistern could be removed and
the district heating used is reduced to 0.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
6.1.1 Energy value and emissions
A regulation about emission trading has been a reference since the year of 2007 for calculating emissions and establishing energy use from different kinds of fossil fuels. This regulation
has been put together by the Swedish environmental protection agency which has authority
in this matter in Sweden. The regulation is called “NFS 2007:5” and has been used by Avesta
Works for calculating emissions and energy use. This regulation has now been updated and
is called “NFS 2012:05”. These updated values have been used in the Avesta Works application of emission trading for the new emission trading period [5] [6].
To calculate the emissions from incinerating WRD oil at Avesta Works an emission value
from “NFS 2012:05” has been used. The Swedish environmental protection agency emission
value for WRD oil is 76.2 tons
/TJ and the effective net calorific energy value is 38.16
GJ/ fuel [6]. These values are used in the energy use and the
emission calculations.
The amount of
emissions from WRD oil is calculated as a mass balance. The supplier of
the oil notes that the oil always contains less than 0.1 % of S, which is noted in the emission
calculation.
The dust emissions is based on measuring made at L76, it was determined that for every ton
of WRD oil incinerated there where an emission of 0.1 kilograms of dust [6].
6.1.2 Price for oil
The pricing regarding oil is, as with many other commodities, inherently volatile which has
been shown over the last 40 years. Large fluctuations in oil prices started in the 70s and the
last large fluctuation where during 2008-2009. The price is now stabilizing after the shocking
increase in oil prices. However, the fluctuation in 2008-2009 where not as large as what have
been observed in the early 1990s.
There are a lot of factors to include in how the pricing for oil is affected. Some factors are
exchange rates, political differences, global stock, supply and demand and much more. Forecasts have been made for close future oil pricing in different studies. In the “Medium-term
oil market report 2012”, made by the international energy agency (IEA), an assumption have
been made regarding oil pricing. It’s expected that oil prices is going to remain volatile because of supply and demand uncertainty. The assumption used in the report shows a decrease of the average import price for oil over the 2011-2017 period by approximately 20 %.
The assumption is based on short- and medium-term models which are generated by using a
combination of historical ICE Brent futures and a six-year forward price curve [23].
The best way to get a proper price for oil useable for this report, without making it complex
and revealing company prices, is to use an approximately price which isn’t far from the truth.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
The price that was used in this report is X SEK per
, which is about X SEK per MWh [37].
This price has been used to calculate the results of this report.
6.2 Natural Gas
Natural gas is the third most important source of energy in the world after oil and coal [10].
It’s one of the cleaner, safest and most useful fossil energy sources. Natural gas is a generic
name that includes several hydrocarbon gases. While natural gas mostly contains of methane, it also contains ethane, propane, butane and pentane. The composition of natural gas
can vary widely; table 6.1 shows the variation of natural gas [9].
Table 6.1: Shows the variation of composition regarding natural gas [9].
Methane
70-90 %
Ethane
Propane
0-20 %
Butane
Carbon Dioxide
0-8 %
Oxygen
0-0.2 %
Nitrogen
0-5 %
Hydrogen Sulphide
0-5 %
Rare Gases
A, He, Ne, Xe
Trace
Industrial use of natural gas has been of interest for some time, at least for 100 years.
Examples for natural gas use in industry today is waste treatment and incineration, metal
preheating, drying, glass melting and fuel for industrial boilers [9]. Natural gas is the most
used energy gas in Sweden. Since the introduction of natural gas in 1985, the townships
connected to the Swedish natural gas network is consuming approximately 20 % of their
energy from natural gas. Because of the poor infrastructure of the natural gas network, few
industries are able to use natural gas in their processes [10]. According to the Swedish
environmental protection agency a large investment in natural gas infrastructure would risk
tie the Swedish energy system to fossil fuels for a long time, which would make it harder to
reach the long-term environmental commitment in Sweden [11].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
To be able to use natural gas, where there is no network, there is a possibility to use a “newold” technique. When you condense natural gas to the condense temperature of minus 162°
Celsius, the volume of the liquid is approximately one six hundredth of the gas volume. With
natural gas in liquid form (LNG) an effective transportation is possible without a network.
When natural gas is in liquid form it could be distributed like any other liquid fuel; by truck,
boat or train. The energy company “Aga” has built a terminal to store LNG in Nynäshamn,
which allows LNG-use in the middle parts of Sweden. This could possibly be of interest for
Avesta Works, but it’s up to Outokumpu to decide. The terminal capacity is 20 000 . The
liquid natural gas comes mostly from gas fields in Norway and arrives in special built ships
with vacuum isolation [13].The transportation from Nynäshamn could either be by train or
truck. The distance between Avesta and Nynäshamn is about 218 kilometers when driving a
car [14].
The technique of using LNG creates flexibility, independency of natural gas politics and
infrastructure [13].
When natural gas condensates at the temperature of minus 162° Celsius, some gases with
higher condense temperatures is separated from the LNG. The result of this is a higher
amount of methane and ethane which should make a difference in both emissions and
energy value [12] [13].
In the event of a conversion at Avesta Works to liquid natural gas, the natural gas is going to
be used instead of LPG and WRD-oil in the process, thus mainly for pre-heating and process
heating.
6.2.1 Energy value and emissions
The energy value of LNG is not yet defined at the moment of this thesis according to staff at
the Swedish environmental protection agency. Because of this, LNG data from “Energy gas
Sweden” is used. The effective net calorific energy value of LNG is 38.69 MJ/N [28].
The
ton
emission of LNG is updated in NFS 2012:5 and is now the same as natural gas, 56.5
/TJ [5].
6.2.2 Price for LNG
The price setting of natural gas is mainly based on two different mechanisms, the oil indexation and the gas-to-gas competition-based prices (spot prices). Shortly explained, the oil indexation price model relates the natural gas costs to the costs of crude oil meanwhile the
gas-to-gas mechanism is based on supply and demand. There are also lesser mechanisms
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
available such as bilateral monopoly which is based on agreements between countries on
pricing.
The pricing of these mechanisms vary widely. The oil indexation price model clearly have
following the increasing oil prices meanwhile spot prices haven’t in the same degree.
History has shown a strong link between oil pricing and natural gas pricing in Europe due to
the use of oil indexation model but also due to the increased demand of gas with higher oil
prices. The same goes for LNG, which is shown in LNG-dependent countries such as Japan
and South Korea. The pricing of LNG has had a time lag of approximately three months in
comparison of oil pricing [54].
When to determine a price for LNG, useable in this report, there is no reference to use because of no LNG is being used at Avesta Works. However, I came in contact with X at “X”
which has been working with companies regarding LNG investments. According to X, most
companies which are using LNG as fuel in Sweden today pays approximately between 40 to
50 Euro per MWh in 2012-13 [17].
In the feasibility study, for the natural gas conversion, a different price has been used based
on how much Avesta Works is aiming to pay for liquid natural gas. However, it has been decided that a calculated highest price for LNG per energy value to gain a pay-off time of five
years, is the most suitable way to present this reports economy conclusions.
6.3 Liquefied petroleum gas (LPG)
Liquefied petroleum gas is a generic name for propane and butane gas. LPG is mostly used
by the industry in Sweden, often at heat treatment processes in steel and iron industry. LPG
is also very popular all over the world for heating in households [1] [2].
In Sweden there are three different refineries who extract LPG. Two is in Gothenburg and
one is in Lysekil. Most of the LPG in Sweden comes from the natural gas field in North Sea
owned by Norway [3].
The distribution in Sweden is mostly based from large stocks of LPG in several cities with
receiving ports. These cities are Karlshamn, Sundsvall, Piteå, Stenungsund, Gothenburg and
Lysekil. From these stocks LPG is distributed either by truck or train in pressured cisterns to
keep the gas in liquid form. The capacity of trucks is between 8-32 tons of LPG and the capacity of train cisterns is 20 to 52 ton.
Large consumers often have an LPG cistern close to the consuming burners. If smaller quantities of LPG are required, there is no need to for an evaporator. When LPG is distributed by
truck or train, it isn’t all in liquid form. Some gas still remains. This gas could be used by a
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
small consumer. If a high quantity of LPG is needed, then it has to be transported to an
evaporator [4].
At Avesta Works LPG is mostly used for preheating, heat treatment of steel and refining
steel. From the hot rolling mill, where bought LPG arrives, all the LPG is distributed to a cistern where the withdrawal is made. From the cistern the LPG is distributed to the evaporator, which also is located at the hot rolling mill. From the evaporator the gaseous LPG is distributed to both the melt shop and hot rolling mill. The main purpose of having the evaporator and cistern close to the hot rolling mill is because of the high LPG use at the walking
beam furnaces.
The combustion of LPG at Avesta Works has proven to be beneficial comparing to oil mainly
due to the clean combustion and good regulation of a gaseous fuel.
6.3.1 Energy value and emissions
In NFS 2012:05 we also find that the effective net calorific value for propane and butane
(LPG) is 46.05 GJ/ton and the emission factor regarding carbon dioxide is 65.1 ton CO2/TJ
LPG. These values have been used in the calculation of carbon dioxide emissions and energy
use from LPG at Avesta Works [5].
6.3.2 Price for LPG
Because of LPG is being refined from both natural gas and oil, the price setting of this fuel
should depend on both of these fuels. And because of the strong link between natural gas
and oil it’s likely that LPG will follow the price curve of oil for the next few years.
The best way to get a proper price for LPG is by using an approximated cost for LPG that is
similar of what Avesta Works have been paying. The cost for LPG used in this report is X SEK
per MWh fuel [7].
6.4 Comparison between LPG, Fuel Oil and LNG
To get an overview over the differences of these fuels, it is needed to both compare the
pricing, the emissions and the energy value of each fuel. It’s because every part is connected
to the calculations in chapter 7 in this study. Another important factor to include is the heat
transfer when combusting different fuels.
6.4.1 Energy value
The importance of effective energy value in this study is connected to the calculation of price
per MWh (useful), emissions per MWh and oxygen use per MWh. This is the best way to
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
compare different fuels from energy, environment and economic point of view because it’s
the only way they can be compared fairly. But to calculate “per useful amount of energy” the
energy value of the fuel is needed to be established.
The comparison of energy values that is used in the energy calculations is shown in table 6.3.
Table 6.3: Shows the difference in energy value of LPG, WRD-oil and LNG. The values are shown in
the commonly used unit for each fuel [5] [28].
Energy value
[GJ/Ton]
LPG
WRD-Oil
LNG
Energy value
[MJ/
]
46.05
Natural form
Gaseous
38160.0
Liquid
38.69
Gaseous
6.4.2 Emissions
Emissions are strongly connected to economy. There are several regulations in Sweden
forcing industrial operation to become more environmental friendly. One of them is IED
(Industrial Emissions Directive) which is monitored by the European Union. Some emissions
that is part of IED that also concerns Avesta Works is dust,
,
and more [5].
Another regulation that concerns Avesta Works is the climate convention and Kyoto
protocol, which both are ratified in Sweden. The goal of these regulations is mainly to reduce
carbon dioxide emissions, which concerns Avesta Works [5].
The emissions trading regulation regarding carbon dioxide also concerns Avesta Works [5].
Since the regulation was introduced to Avesta Works, all the assigned emission rights have
been enough for Avesta Works to not having to buy emission rights. On the contrary, some
emission rights have been sold to other companies [6].
There are also other directives and regulations that concerns energy and thus Avesta Works.
Some examples are the goal of increasing energy efficiency (20-20-20) [29], electric
certificates and more.
In table 6.4, which shows a comparison of LPG, WRD-oil and LNG from an environmental
point of view, it’s clear that of these three fuels, LNG is the cleanest fuel to combust. The
difference in
emissions between LNG and WRD-oil is approximately 25 %, favoring LNG.
Table 6.4: Shows a comparison of emissions from the fuels of interest.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
[Ton/TJ]
Dust [kg/ton]
LPG
65.1 [5]
About 0 [5]
0 [5]
WRD-Oil
76.2 [5]
Less than
1%/ [27]
0.1*
LNG
56.5 [5]
About 0 [5]
0 [5]
*Based on measuring
6.4.3 Fuel costs
The price of each fuel makes, as suspected, the main difference between the fuels and will
have a major influence on the possible investment. The price of LPG and WRD-oil is an approximation and the price for LNG is based on the statistics [37] [7]. Because of the strong
link between the different fuel prices, the price differences have been used to calculate a
pay-off time in chapter 7. Table 6.5 shows the price difference of each fuel.
Table 6.5: The table shows the difference in price based on effective energy value. The price for LNG
in this table is 45 Euro/MWh
Price [SEK/MWh]
Difference (based on
WRD)
LPG
≈X
(+) X %
WRD-Oil
≈X
X%
≈ 380 (2013-05-14)[8]
(-) X %
LNG
6.4.4 Heat transfer
Heat transfer occurs from media to media all the time around us. Whenever there is a heat
difference between two objects, there will be a heat transfer. Heat transfer occurs mainly in
3 separate ways. These are heat conduction, convection and radiation. Because of different
fuels leaves behind different amounts of flue gases and content of these gases, there will be
a slight change of heat transfer.
Heat conduction is, simply put, a transfer of kinetic energy from a warmer object to a colder
object. An example of this is a furnace wall which, through heat conduction, transfers energy
from inside the furnace to outside the furnace (as an “energy loss”). Another example is
when the surface of a steel slab transfers heat to the inner part of the slab.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
The heat transfer from a wall to a fluid is partially made through convection. The fluid which
is in contact with the wall gets hotter and its density is decreased. These particles will ascend
because of the density decrease.
Energy can be transferred from one object to another through electromagnetic waves. These
waves are called radiation. Every object with a temperature above the absolute coldest
temperature (0° K) emits heat waves [44]. The most important radiation transfer is from the
flame and flue gases from a burner installation.
Because of the complexity of the heat transfer and the large amount of different installation
at Avesta Works, the heat transfer difference between the different fuels weren’t analyzed
to the extent as it could have been. A master thesis made in 2008, with a similar object of
this thesis, looked deeper into the difference between natural gas combustion and WRD-oil.
It was decided that the heat transfer differs only a little bit and could be considered insignificant. The difference of radiation heat from the lower amount carbon dioxide but higher
amount of vapor is estimated to cancel each other out [27].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
7 Results
In this chapter, I will present the results of the possible energy, environment and economy
positives or negatives that might occur with a potential conversion from LPG and WRD-oil to
LNG at Avesta Works.
In case of a conversion to LNG, the amount of needed energy for processing will approximately be the same. With no major burner upgrades, the energy efficiency will stay relatively the same as before the conversion. To get increased energy efficiency with this conversion, the old conventional burners are needed to be changed for a more effective technique
(for instance regenerative technique). As stated in chapter 6.4.4, the heat transfer is complex and could be analyzed more. However, the heat transfer is assumed to stay unchanged
and doesn’t play a part in this chapter. However, the amount of needed district heating to
vaporize LNG to natural gas will be different from today’s LPG vaporization. Also, the steam
boiler connected to the furnaces at the annealing and pickling line isn’t needed if a conversion would come to pass [52]. The energy differences are presented in chapter 7.1.
The large difference when it comes to environment changes is the carbon dioxide emissions,
but there will also be a reduction of sulfur, dust and potentially NOx as well. It is impossible
to calculate a decrease of NOx emissions before the chosen burner technique is made. But
for the purpose of showing the economic and environmental potential difference an estimated NOx reduction of 25 % is used in this thesis. The difference in emissions is shown in
chapter 7.2.
In the economy analysis in chapter 7.3 presents possible economic factors found regarding a
conversion to LNG at Avesta Works. Factors included are oxygen and ammonia use, maintenance costs, carbon dioxide emissions and energy use.
7.1 Energy analysis
7.1.1 Energy use for steam production
The energy use to produce steam would no longer be necessary in case of a conversion. The
steam boiler has earlier been generating steam to provide heat for both the pickling process,
the oil cistern and to atomize the oil in the burners. Recently (2012-13), an investment was
made to convert all steam users to district heating, except for atomizing of the oil. Because
of this and the fact that the boiler is relatively old, it is highly oversized, energy ineffective
and needs a lot of maintenance [52]. Earlier measurements and calculations resulted in an
energy efficiency of 60 % for the steam boiler.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
The average amounts of saturated steam needed to atomize the oil in the burners are 450 kg
per hour [52]. The pressure of the saturated steam is 7 bars which makes it´s enthalpy
2763.5 kJ/kg. The calculated amount of energy needed from steam have been about 3
GWh/year (production reference of 2012).
The flue gas boiler has produced a decent amount of the required amount of steam. With
the measured temperature and the enthalpy of the flue gases of the year 2012 and the
working temperatures of the flue gas boiler, the calculated useful (sometimes the flue gas
boiler produce excess amounts of steam) steam production where about 2 GWh. About 1.4
GWh/year is the calculated amount of oil-energy needed to the steam boiler (production
reference of 2012).
7.1.2 District heating use
When it comes to production of district heating, a change might occur if a more energy efficient burner technique is chosen. If not however, approximately the same amount of energy
will be available for the flue gas boilers and furnace cooling system, which means that the
same amount of district heating would be produced. Because of this uncertainty, it is estimated in this report that the district heat production won’t change.
However, the amount of district heating required to vaporize LNG will differ from today’s
vaporization of LPG. That’s because of the different amount of energy needed to vaporize
these fuels. Also, the total amount of energy needed from LNG would be larger than LPG
because of the conversion from oil in the annealing and pickling line.
According to “Energy Gas Sweden”, the approximate heat requirement for vaporizing LNG is
140 kWh per ton vaporized LNG or 10.2 MWh per GWh LNG (net calorific energy value) [28].
This value could be compared to the district heating needed to vaporize LPG at Avesta Works
in 2012, which were approximately 126 kWh per ton LPG or 9.8 MWh of district heating per
GWh LPG. The calculated increase of district heating use is 993 MWh (in relation to 2012).
There is also no need to heat the oil cistern any more. There is no older measurements regarding steam needed to heat the oil cistern and I have only been provided with a calculated
amount of needed district heating for all the consumers at this installation (pickling process,
a few offices and a few more consumers). The total calculated amount of needed district
heating is 4 GWh/year for this installation. It is estimated, in this report, that the oil cistern
needs 2 GWh/year of district heating.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
7.2 Emission analysis
The emissions of interest are sulfur, dust, nitrogen dioxide and carbon dioxide. The
reduction of these emissions, in case of a conversion, is shown in table 7.1. For a more detailed presentation (when the emissions are linked to each burner installation), see attachment 3-4.
Table 7.1: Shows potential reduction of emissions at Avesta Works with LNG as the only fuel [6]
Emission
Emission value from WRDoil and LPG 2012
Emissions in case of LNG
conversion
80 000 ton
65 700 ton (-17,9 %)
43 ton
About 0 (-100 %)
139 ton
123.5* (-11 %)
970 kg
About 0 (- 100 %)
Dust
*Estimated
With a lower amount of
emissions from the combustion, there is a possibility to reduce
the ammonia used for cleaning the flue gases at the acid regeneration plant and hot rolling
mill, and still keep the emissions at the same level as before. Other installations are estimated to reduce NOx emissions by 25 %.
The flue gas compositions could also be calculated and approximated. With the compositions used in this report (presented in attachment 2), the flue gas compositions compared to
the energy values are shown in table 7.2.
Table 7.2: shows the difference of flue gases when combusting LPG, LNG and WRD-oil. The unit
used is molar flue gas per kWh energy
O
LPG
5.321
7.072
0
0
0.142
WRD-Oil
6.03
5.36
0.001
0.001
0.212
LNG
4.562
8.700
0
0.014
0.142
7.3 Economy analysis
The costs of the investment are based on the feasibility study, which includes all the costs
for the conversion. The total cost for the investment is calculated to X million SEK. The price
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
difference for the fuels makes the most substantial difference in the economic analysis. Estimates made in the feasibility study show a reduction of fuel cost with approximately 30 %.
The main goal of this chapter and study is to establish a price/energy that is needed to receive a “pay-off time” á five years.
7.3.1 Oxygen costs
At Avesta Works, oxygen is used for combustion and for processing. The difference in oxygen
use, concerning the combustion, is mainly the stoichiometric air/oxygen-fuel ratio needed to
fully combust the fuel and the amount of needed excess air/oxygen to ensure an effective
combustion.
To be able to calculate the air-fuel ratio, approximate compositions of the fuels are needed.
These are gained from a safety sheet from Statoil (LPG), Shell (WRD) and Energy gas Sweden
(LNG). The compositions are shown in attachment 2.
The main composition of LPG is propane, with over 95 % of the total weight. The other main
substances are petroleum gases, C3-4. Petroleum gases C3-4 are gases with hydrocarbons of
3-4. These gases contain mostly butane, which will be used in the oxygen calculation.
The composition of WRD-oil is mainly carbon and hydrogen. It also contains some sulfur and
nitrogen [27].
The composition of LNG differs depending on which supplier of LNG that Avesta Works
chooses, that’s why typical values will be used for the composition of LNG. It’s gained from
“Energigas Sverige”.
With the given compositions of the fuels, it’s possible to calculate the stoichiometric
air/oxygen-fuel ratio for respective fuel. The calculation results are displayed in table 7.3. For
the actual calculation, see attachment 2.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Table 7.3: Shows the calculated stoichiometric oxygen-fuel ratio and oxygen depending on the energy value of the fuel.
Oxygen-fuel ratio
Oxygen / MWh
LPG
3625.28 g/kg
283.5 kg/MWh
(+1.6 %)
WRD-Oil
3346.0 g/kg
279.0 kg/MWh
(0 %)
LNG
3065.9 g/
285.2 kg/MWh
(+2.2 %)
As seen in table 7.3, the fuel which requires most oxygen or air per MWh is LNG. The difference in oxygen use, depending on the effective energy value, of WRD-oil and LNG is about
2.2 %. This will result in a higher oxygen use at L76 and slight higher oxygen use at LPG installations. The burner installations using air for combustion could be considered as negligible in
this matter due to the small cost for increased amount of electricity use for transportation of
a little more air (based on that no fans is needed to be replaced with larger ones).
The excess oxygen needed to be certain of complete combustion vary depending on fuel and
combustion. With higher amount of oxygen in the flue gases comes a higher flue gas
temperature and the energy loss will be larger. However, if the excess oxygen value is lower
than 1, there will be a higher amount of carbon monoxide emissions and lower combustion
efficiency [38]. The excess air or oxygen is often measured and controlled based on air or
oxygen ratios. Usual excess air values for gases are between 1.05-1.10 [44]. Because of the
different kinds of processes, furnaces and burners at Avesta Works, the excess oxygen value
for LPG combustion differs a bit from each other. However, the average excess oxygen value
could be used in the oxygen calculation.
Average excess oxygen used at MS could be calculated by using the total oxygen and LPG
consumed for combustion in 2012. The oxygen value is the input value of oxygen to the
combustion. However, there is also air leaking into all burner chambers which is not of importance for this calculation because the amount of leaked air is estimated to be the same
after a conversion.
The amount of excess oxygen used at L76 is also needed to be calculated. There haven’t
been oxygen measurements in the flue gases for some time (because of breakdown). The
oxygen supply has instead been a ratio of N
per kg WRD-oil. The ratio used is between
2.3-2.5
per kg oil depending on process parameters [50]. The ratio used in the calcula-
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
tions is 2.4
per kg oil. Table 7.4 shows the difference in excess air depending on fuel and
attachment 2 shows the calculations.
Table 7.4: Shows the average value for excess oxygen at Avesta Works and the estimated excess
oxygen value for LNG (same as LPG) [44] [50]
Fuel
Excess oxygen
LPG
1.6 %
WRD-Oil
2.44 %
LNG
1.6 %
With the stoichiometric oxygen-fuel ratio and the difference in excess oxygen it is possible to
calculate the economic difference in oxygen use in case of a conversion. The price for oxygen
at L76 is estimated to X SEK per
and the price for oxygen at MS is estimated to X SEK
per
based on historical costs at Avesta Works. The results of the oxygen calculations
are presented in table 7.5.
Table 7.5: Shows the oxygen use for combustion before and after a possible conversion and the
difference in oxygen expense at Avesta Works [41]. The oxygen used at the converter heater is not
being considered because, with the data given, it wasn’t possible to separate the oxygen used by
the burner and the oxygen used to reduce coal from the steel.
Process
Oxygen use 2012
[kN ]
Oxygen use after
a conversion to
LNG [kN ]
Difference i
oxygen expense
[kSEK]
Melt Shop and continues casting
7 083.8
7 124.5
X
Hot Rolling Mill
0
0
X
Annealing and Pickling
Line (L76)
17 775
18 006.4
X
Total
24 858.8
25 130.9
X
As seen in table 7.5, a larger amount of oxygen expense is calculated. It should also be noted
that the composition of the fuels varies depending on where they come from. The composi-
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
tion of LNG used for the oxygen calculation is, as earlier stated, from typical values. If a conversion would happen in the future, a better value could be acquired from a distributor.
7.3.2 Ammonia costs
Ammonia is used, at Avesta Works, for cleaning flue gases from
emissions by Selective
Non Catalytic Reduction (SNCR) or Selective Catalytic Reduction (SCR) technique. SNCR technique is used at the walking beam furnaces and the acid regeneration plant and SCR is used
at the annealing and pickling line.
SNCR is a post-combustion technology that is designed to lower
emissions by adding
ammonia or urea reagents to the flue gases which reduces
to
and water. The
reduction of
emissions varies from 30-50 %. The reaction takes place at a high but small
temperature window, from 900 degrees Celsius to 1150 degrees depending on the reagents.
Ammonia that isn’t part of the reaction could mostly be separated in various types of solid
waste but a lesser part is discharged with the flue gases. With a lower amount of created
emissions, a lower amount of ammonia is needed to be injected to clean the flue gases
[45] [46].
SCR technique also uses ammonia or urea reagents to reduce
to water and .
However, it’s not a thermal reaction in contrast to SNCR but uses catalysts instead. It’s a
larger investment compared to SNCR but SCR have lower operation costs and higher
capability to reduce
(up to 80 %) [51].
As stated earlier in the report, the amount of
emissions are estimated to be at the same
level for the installations using flue gas cleaning, the annealing and pickling line and the
walking beam furnace at the hot rolling mill. However, the amount of ammonia used to
clean the flue gases to the same level as before should be possible to reduce with the same
percentage that the
emissions would differ from the combustion. The emissions difference is shown in table 6.4.
Given the price of approximately X SEK per ton ammonia in 2012, the economic benefit
would be X SEK per year as shown in table 7.6.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Table 7.6: Shows the possible reduction of ammonia used for cleaning flue gases [42]
Process
Ammonia used
[tons/year]
Possible
ammonia use
after conversion
[tons/year]
Decreased purchase
cost [kSEK/year]
Annealing and Pickling
Line
386.5
386.5*
0
Hot Rolling Mill
157.2
117.9
X
Acid regeneration plant
131.8
125**
X
Total
675.5
629.4
X
*Ammonia is entirely used to reduce
from the pickling process.
**Ammonia is mostly used for cleaning
from the acid regeneration process and entirely. Because of this, a lower amount of decreased ammonia use is estimated.
7.3.3 Maintenance costs
Because of LPG and LNG being similar from a combustion perspective (both being gaseous
and relatively clean), it’s most likely that there won’t be any changes in maintenance work or
the productivity of the LPG installations. However, the installation at L76 that uses oil as fuel
would benefit, regarding maintenance and productivity, from a conversion to LNG.
After a consultation with the company Steuler, which have been involved with the installation and operation of the burners, some problems with the combustion of oil have been
identified at the catalytic NOx installation. There have always been problems with the combustion when the burners are operated at a very low load due to a high exothermic reaction
at the catalyst. This has resulted in depositions at the air/air-plate heat exchanger which is
now needed to be cleaned regularly. With a LNG conversion, the frequency of the cleaning
would be reduced considerably which would result in lower maintenance and productivity
losses [18]. The approximate cost for maintenance is 100 000 SEK per year [35]. The productivity losses is minimal because the cleaning work on the burners and heat exchangers are
well cooperated with the regular maintenance work. The productivity losses could be considered negligible.
The second maintenance difference with LNG as fuel is the steam system which atomizes the
oil at L76. This system, as stated in chapter 7.1, is no longer needed when using a gaseous
fuel. Because of it being oversized and ineffective, an estimated maintenance cost of 150
000 SEK per year could be reduced to zero [53].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
7.3.4 Carbon dioxide emission costs
As seen in chapter 6.4, carbon dioxide emissions favor LNG. The reduction of carbon dioxide
emissions would approximately be 14 300 tons following a conversion to LNG (see attachment 3 and 4). The cost of carbon dioxide emissions are changing from day to day and with
the new period of emission trading starting in 2013 it’s hard to use a reliable price for carbon
dioxide emissions. It has been decided that the cost for carbon emissions will relate to the
second emission trading period (2008-2012). The approximate cost for 1 ton of carbon dioxide during the second period where 12 Euro [40]. With a reduction of 14 300 tons, the approximate economic benefit would be 171 600 Euro per year.
Chart 7.1: Shows the carbon dioxide emissions spot price per ton from 2008-2012 [40]
7.3.5 Energy costs
As seen in chapter 7.1, there is a calculated reduction of energy use from steam at L76, a
calculated increase of district heating used at the evaporating station and an estimated decrease of district heating for oil heating. The energy cost differences are presented in table
7.7 and the district heat calculation for vaporizing is shown in attachment 5. The price of
district heating is estimated.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Table 7.7: Shows the calculated economic difference in energy use between todays installations
and a LNG conversion
Energy difference
[MWh/year]
Estimated economic
difference [SEK/year]
Oil
1400
X
District heating
1000
X
7.3.6 Economic summary
The largest economic differences in case of a conversion, except the fuel costs, are the
reduction of carbon dioxide emissions and the reduction of WRD-oil at L76. When comparing
these factors to the investment cost of approximately X million SEK it’s clear that the fuel
cost will be the large dominant factor in the economy calculation. All the calculations in this
chapter are summed up in table 7.8.
Table 7.8: shows the difference of the economy factors in chapter’s 6.3.1-6.3.5. The positive costs is
the, excluding the price of each fuel, beneficial economy factors concerning LNG. The negative
costs are the increased costs in case of a conversion.
Oxygen
[kSEK]
Ammonia
[kSEK]
Maintenance
[kSEK]
Emission
[kSEK]
Energy
[kSEK]
Summary
[kSEK]
LPG and Oil
-
+X
+250
+1 478
+X
+X
LNG
-X
-
-
-
-
-X
Total
-X
+X
+250
+1 478
+X
+X
In addition to the fuel cost benefits, a conversion to LNG would also give an economic
benefit of approximately X SEK per year (with the estimations and data given). With all the
economy factors and fuel costs included over a five year period, the cost for LNG to achieve
a pay-off time of five years should not be larger than approximately 400 SEK per MWh. The
calculation is presented in attachment 6.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
8 Other similar investments
It’s not only Avesta Works that is considering converting from LPG and oil to natural gas.
Many companies in the Swedish west coast, which is connected to the natural gas network,
have taken the opportunity to switch to natural gas. Others are considering or preparing for
a LNG conversion, where there isn’t any natural gas network. A few similar investments
made are mentioned in this chapter.
8.1 SEMAB Stenugnsund
SEMAB, the town district heating company in Stenugnsund, is converting all their LPG and
some oil to natural gas. The district heating company has earlier used industrial waste heat
for district heating and as a complement LPG and oil, in case of production stop from the
industries or out of necessity of more heat. Now, instead of LPG and oil, they are going to
use natural gas as a backup.
One reason for this conversion was a safety issue. The LPG tank where to close to the
surrounding settlements. A pipeline instead would eliminate that risk [30].
8.2 Uddeholms AB Hagfors
One of the world’s leading company producing industrial steel tools “Uddeholms AB”
decided in 2011 to convert from oil and LPG to LNG at their production facility in Hagfors.
They started to build their own receiving station for LNG in September 2011. With this
conversion, Uddeholm AB became the first steel industry in Scandinavia to convert to LNG.
The main reason for the conversion was the environmental and economic benefits. With the
lower emissions from LNG then LPG and oil, the company gets closer to their environmental
goals. And with the economic benefits the company strengthens their position on the steel
tool market [31].
The calculated results of this conversion are:





Decrease in energy use by 20 GWh each year
Decrease in carbon dioxide emissions by 20 %
Dust and sulfur emissions decrease to 0 from the furnaces
emissions decrease by 40 %, mostly due modernizations of the furnaces
The investment has a pay-off time of approximately 4 years [32]
After contact with Uddeholm AB in Hagfors, it was clear that the decrease in energy use is
mainly because of new burner installations. The burner technique that these calculations are
based on is the regenerative technique explained in chapter 4.2. A furnace converted to re-
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
generative technique (from non-regenerative technique) at the production site has decreased the use of energy by as much as 45 % [43].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
9 Conclusion
The burner installations at Avesta Works are mainly using techniques to capture energy from
the flue gases except for a few smaller installations. However, the installation at L76 could
be better at using the heat from the flue gases. The flue gas boiler installed today is not effective and a considerable amount of energy could be saved by either installing a new boiler
to produce district heating.
A conversion to LNG would reduce the energy use at L76 and increase the district heat
requirement at the vaporizing station. The steam system could be taken out of service at L76
and an energy reduction of approximately 1400 MWh of oil is expected. A decrease of 1000
MWh/year of district heating is also expected.
Because of the difference of heat transfer due to radiation it could be interesting to further
study the flame differences of oil and natural gas combustion at the annealing and pickling
line. It should also be interesting to know how the increased amount of vapor (approximately 40 %) in the flue gases affects the steel quality.
LNG is superior when it comes to emissions. A conversion to LNG would reduce carbon
dioxide emissions by approximately 18 % overall at Avesta Works with the highest reduction
at L76. It would also reduce
and dust emissions from combustions to about zero. Outokumpu is, according to Outokumpu’s annual report 2012, aiming to reduce all kinds of
emissions in the future and a conversion to LNG would make a large positive difference to
achieve these goals. In addition to the goals of Outokumpu, there will most likely be higher
requirements for lower emissions from EU in the future.
The largest economic difference by far, more than 90 %, is the difference in fuel costs. To get
a pay-off time close to five years the price for LNG must be lower than 400 SEK per MWh.
When compared to the costs of LNG today, which were between 40 to 50 Euros per MWh
(344-430 SEK, 21/5-2013) [8], it is fully possible that a conversion to LNG would have a payoff time lower than five years. However, it should be considered that the Swedish currency is
strong at the moment compared to the currency Euro. Another factor to consider is that the
price of fuel varies a lot over time and can’t be exactly predicted. However, as discussed in
chapter 5, there is a strong link between natural gas, oil and LPG prices.
Because of the dominant factor being the difference in fuel costs a higher production, which
would increase the fuel used, will benefit the economy calculation considerably. As seen in
chapter 2, Avesta Works is dimensioned for a much larger production of steel.
There are also other positives to consider regarding a conversion to LNG. The local natural
gas network could be used for biogas as well as natural gas (to further reduce emissions).
There is also many safety benefits of using LNG instead of LPG explained in the feasibility
study and in “Anvisningar för flytande naturgas (LNGA 2010)”.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
The main conclusion of this study is that LNG is a viable option for Avesta Works instead of
both LPG and oil from an energy, environment and economic point of view.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
References
Literature
Surname, First name. Title. Year
[23] OECD/IEA, Medium-Term Oil and Gas Markets. 2011.
[24] Avesta Works, Allmänna broschyrer om Avesta Jernverk. 2012.
[25] Avesta Works, Brännare Avesta Works, kapacitet och förbrukning. 2012.
[26] Avesta Works, Energirapportering Avesta Works, rapporteringsfiler. 2012.
[28] Energy gas Sweden, Anvisningar för flytande naturgas (LNGA 2010). 2010.
[33] C.Baukal, Industrial Burners Handbook. 2003.
[44] Alvarez, Henrik. Energi Teknik. 2006.
[51] G.A. Somorjai, Introduction to surface chemistry and catalysis. 1994.
Websites
Author. Title. Date. Website.
[1] LPG-Solutions. General facts on LPG. 2013-02-11. http://www.lpgsolutions.co.uk/facts.html
[2] Energy gas Sweden. Gasol. 2013-02-11. http://www.energigas.se/Energigaser/Gasol
[3] Energy gas Sweden. Gasol - ursprung. 2013-02-11.
http://www.energigas.se/Energigaser/Gasol/Ursprung
[4] Energy gas Sweden. Gasol – Distribution. 2013-02-11
http://www.energigas.se/Energigaser/Gasol/Distribution
[5] Swedish environmental protection agency. NFS 2012:5 and NFS 2007:5. 2013-02-12
http://www.naturvardsverket.se
[8] Valuta.se. Valuta Euro/Sek. 2013-04-14.
http://www.valuta.se/currency/showgraph.aspx?valutaid=638305
[9] Naturalgas.org. Natural gas background. 2013-02-12.
http://www.naturalgas.org/overview/background.asp
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
[10] Energy gas Sweden. Naturgas. 2013-02-12.
http://www.energigas.se/Energigaser/Naturgas
[11] Swedish environmental protection agency. Fossila bränslen. 2013-02-12.
http://www.naturvardsverket.se/Start/Verksamheter-med-miljopaverkan/Energi/Fossilabranslen/
[12] Aga. Vad är LNG? 2013-02-12.
http://www.aga.se/international/web/lg/se/like35agase.nsf/docbyalias/what_is_lng
[13] Gasbilen.se. LNG. 2013-02-14. http://www.gasbilen.se/Att-tanka-dingasbil/FAQFordonsgas/FAQLNG
[14] Eniro.se. Färdbeskrivning. 2013-02-14. http://eniro.se
[15] EON. Olja. 2013-02-14. http://www.eon.se/om-eon/Om-energi/Energikallor/Olja/
[16] Energimyndigheten. Olja. 2013-02-14. http://energimyndigheten.se/sv/hushall/Dinuppvarmning/Olja/
[17] Statistiska centralbyrån. Priser på naturgas för industrikunder. 2013-02-14
http://www.scb.se/Pages/TableAndChart____212959.aspx
[19] Gävle hamn AB. Olje- och kemikalieterminal. 2013-02-18. http://www.gavleport.se/olje_och_kemikalieterminal
[20] Nätverket olja och gas. Korta fakta. 2013-02-18. http://www.nog.se/page.asp?node=24
[21] United States Environmental Protection Agency (EPA). Nitrogen oxides. 2013-02-19.
http://www.epa.gov/air/nitrogenoxides/
[27] Master thesis, ”Konvertering från olja till naturgas vid Lulekraft AB”. 2013-05-14.
http://epubl.ltu.se/1402-1617/2008/025/LTU-EX-08025-SE.pdf
[29] Europa. Summaries of energy efficiency. 2013-02-26.
http://europa.eu/legislation_summaries/energy/energy_efficiency/index_en.htm
[30] Swedegas. SEMAB conversion from LPG to natural gas. 2013-02-26.
http://www.swedegas.se/aktuellt/semab
[31] Uddeholm. Conversion to natural gas. 2013-02-26.
http://www.uddeholm.com/b_3365.htm
[32] Energihandboken. Goda exemplar konvertering till LNG. 2013-02-26.
http://energihandbok.se/x/a/i/10790/Goda-exempel--Konvertering-fran-olja-och-gasol-tillflytande-naturgas-.html
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
[34] Talec. Hotwork Combustion Technology, 2013-02-26. http://talec.co.za/burners.html
[36] Swedish environmental protection agency, Appendix 20 Thermal values and Emission
factors energy GWP conversion factors, 2013-03-19. http://www.naturvardsverket.se/Stod-imiljoarbetet/Vagledningar-A-O/Forbranningsanlaggningar-begrepp-och-definitioner/
[38] Engineered concepts. Excess air decreases combustion efficiency. 2013-03-19.
http://www.engineeredconcepts.com/asac/airdecrease.html
[39] European Chemicals Agency. Substance identification. 2013-03-19.
http://apps.echa.europa.eu/registered/data/dossiers/DISS-a0020b11-36b8-2b88-e04400144f67d031/AGGR-94cc1942-eea8-476e-b60c-4fc2c12ad78d_DISS-a0020b11-36b8-2b88e044-00144f67d031.html
[45] Hamon Research-Cotrell. NOx control. 2013-04-15.
http://www.hamonusa.com/hamonresearchcottrell/products/nox
[46] Swedish environmental protection agency. Förbränningsanläggningar för energiproduktion inklusive rökgaskondensering. 2013-04-15.
http://www.naturvardsverket.se/Documents/publikationer/620-8196-9.pdf
[47] BINE. Flameless combustion. 2013-04-22
http://www.bine.info/fileadmin/content/Publikationen/Englische_Infos/projekt_0706_engl_i
nternetx.pdf
[54] International energy agency. Medium-term oil and gas markets. 2011.
http://www.iea.org/publications/freepublications/publication/MTOGM2011_Unsecured.pdf
Contact persons
Surname, First name. Title or company. Year.
[6] Sjödén, Birgitta. Energy and environmental coordinator, Avesta Works. 2013.
[7] Wiklund, Hans. Business controller, Avesta Works. 2013.
[17] Andersson, Mikael. Bergen Energi. 2013.
[18] Goerlich, Karl-Josef. Steuler. 2013.
[22] Nydén, Erland. Energy and environmental coordinator, Avesta Works. 2013.
[35] Stenqvist, Anders. Process Team Manager, Avesta Works. 2013.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
[37] Wendel, Kent. Process Team Manager, Avesta Works. 2013.
[40] Åkerling, Andreas. HUR-gruppen, Swedish Energy Agency. 2013.
[41] Olivesten, Johan. FU-technician media Avesta Works. 2013.
[42] Jansson, Gunnar. Strategic Purchaser Avesta Works. 2013.
[43] Hedlund, Jan. Energy responsible Uddeholm AB Hagfors. 2013.
[48] Lorenz, Wolfgang. Working at MEFKON. 2013.
[49] Matsson, Nils-Olov. Operational safety engineer. 2013.
[50] Hellgren, Jan-Erik. Process developer Avesta Works. 2013.
[52] Sjökvist, Lars. Värmevärden. 2013.
[53] Sjödin, Niklas. Maintenance manager band unit Avesta Works. 2013.
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Attachments
In this section I have presented some of the calculations more explanatory for a closer insight. Some calculations aren’t presented due to preserve data valuable for the company.
Attachment 1 – Combustion theory
During this study, some interesting factors where needed to be calculated to achieve a more
complete investigation of the energy, environment and economic implication of a
conversion to liquefied natural gas. The basics of the oxygen calculations are explained in
this attachment.
To achieve combustion we need a high temperature or spark, oxygen and a fuel. Because of
oxygen is bought by Avesta Works it’s important to calculate the difference in oxygen use for
the fuels part of this study. Equations 1-5 are some of the used equations for the oxygen
calculations and for the balancing of the combustion formula.
(Ideal gas law)
(1)
(2)
(3)
(4)
(5)
The combustion equations are stoichiometric and simplified.
Equation (1) could be used to calculate volume percent to molar per
instance at normal state (P=101.325 kPa, T=273 K and R=8.314):
=
for gases, for
= 44.642 molar/
This value can be used to calculate all components with the unit molar per
. This is used
in the oxygen calculation for LNG because it’s in gaseous form during combustion. However,
if the composition is presented in weight %, it’s needed to calculate molar per kg of all the
components. This is used in the oxygen calculation for oil and LPG. An example of how to
calculate molar per kg fuel for C is shown in equation (6).
90 weight % C:
*
[kmol/kg]
(6)
To ensure complete combustion, a small amount of excess oxygen is needed. A certain
amount of excess oxygen is necessary to achieve a proper and effective combustion. With no
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
excess oxygen, the fuel can’t be fully combusted and the energy efficiency decreases. With
excess oxygen, the combustion is no longer stoichiometric and oxygen will be found in the
flue gases. An example of combustion with excess oxygen is shown in equation (7).
(7)
However, a high amount of excess air or oxygen decreases the energy efficiency considerably. All excess air or oxygen is cooling the flame of the burners and decreasing the energy
efficiency [44].
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Attachment 2 – Oxygen and flue gas calculations
The table shows the composition of LPG used in the oxygen calculation. The right column shows a
scaling of the composition to acquire 100 % weight.
Composition of LPG
Weight [%]
Scaled values
>95
95
Gases (petroleum), C3-4*
<5
5
Methanol
<0.1
0
Ethyl mercaptan
<0.01
0
Propane
Sum
100 %
*Petroleum C3-4 contains mostly butane (C4H10) [39]
The table shows the composition of WRD-oil used in the oxygen calculation. The right column
shows a scaling of the composition to acquire 100 % weight.
Composition of WRD-oil
Weight [%]
Scaled values
C
87.3
86.92
H
13.1
13.0
S
0.05
0.04
N
0.03
0.03
0.01
0.01
100.49 %
100 %
Sum
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
The table shows the typical composition of LNG [28]. The right column shows a scaling of the composition to remove minor gas compositions.
Composition of LNG
Volume [%]
Scaled values
Methane
90.07
90.08
Ethane
8.98
8.99
Propane
0.581
0.60
Nitrogen
0.31
0.33
99.941
100 %
Sum
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Oxygen calculations LPG
Composition LPG weight %
Molar mass
C3H8
95
C
12.01
C4H10
5
H
1.01
Molar calculation
Stoichiometric oxygen calculations
Substance Molar Weight % Molar/kg
C3H8
44.11
95
21.54
C4H10
58.14
5
0.86
Density LPG: 508 kg/Nm3
Combustion of 1 kg LPG
C3H8 + C4H10 + O2 -> CO2 + H2O
Substance [molar]
Needed oxygen [molar]
21.54 C3H8
107.7 O2
C3H8+5O2->3CO2+4H2O
0.86 C4H10
5.59 O2
C4H10+6.5O2->4CO2+5H2O
Sum. Oxygen
113.29 molar/kg
Energy value LPG: 12.79 MWh/ton
Oxygen-fuel ratio: 113.29*32 = 3625.28 g/kg LPG
Stoichiometric oxygen needed: 3625.28/12.79 = 283.5 kg/MWh
Excess oxygen calculation
LPG used at oxygen combustion installations Avesta Works (converter heater excluded): 35139 MWh
Pure oxygen used for LPG combustion at Avesta Works (converter heater excluded): 7 083 840 m3
Weight oxygen: 1.429 kg/Nm3
Theoretical oxygen needed for LPG combustion at Avesta Works: 35 139*283.5 = 10 120 032 kg
Theoretical oxygen needed for LPG combustion at Avesta Works: 10 120 032/1.429 = 7 126 783 Nm3
Average excess oxygen: 6 971 243.2/7 083 840 = 1.6 %
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Oxygen calculations WRD-Oil
Composition WRD-Oil weight %
Molar mass
C
86.92
C
12.01
H
13.0
H
1.01
S
0.04
N
14.01
N
0.03
S
32.07
H20
0.01
O
16.00
Molar calculation
Stoichiometric oxygen calculations
Substance
Molar
Weight % Molar/kg
C
12.01
86.92
72.373
C + H + S + N + H20 + O2 -> CO2 + H20 + SO2 + N2
H2
2.02
13.0
64.356
Substance [molar]
S
32.07
0.04
0.012
72.373 C
72.373 O2
C+O2->CO2
N2
28.02
0.03
0.011
64.356 H2
32.178 O2
2H2+O2->2H2O
H2O
18.02
0.01
0.006
0.012 S
0.012 O2
S+O2->SO2
Approximated density: 883.7 kg/m3
Energy value WRD-oil: 10.6 MWh/Nm3
Combustion of 1 kg WRD-oil
Sum. Oxygen
Needed oxygen [molar]
104.56 molar/kg
Oxygen-fuel ratio: 104.56*32 = 3346 g/kg Oil
Stoichiometric oxygen needed: (3.346*883.7)/10.6 = 279 kg/MWh
Excess oxygen calculation
Oxygen used per kg oil at L76: 3.4296 kg
Density oxygen: 1,429 kg/Nm3
Stoichiometric oxygen needed for combustion: 32g*104.56 = 3.346 kg oxygen per kg oil
Average excess oxygen: 3.346/3.4296 ≈ 2.44 %
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Oxygen calculations LNG
Composition LNG volume %
Molar mass
Methane CH4
90.08
C
12.01
Ethane C2H6
8.99
H
1.01
Propane C3H8
0.60
N
14.01
Nitrogen N2
0.33
Molar calculation
Stoichiometric oxygen calculations
Substance
Molar
Vol %
Mol/Nm3
CH4
16.04
90.08
40.21
CH4 + C2H6 + C3H8 + N2 + O2 -> CO2 + H2O + N2
C2H6
30.06
8.99
4.01
Substance [molar] Needed oxygen [molar]
C3H8
44.11
0.60
0.27
40.21 CH4
80.42 O2
CH4+2O2->2H2O+CO2
N2
28.02
0.33
0.15
4.01 C2H6
14.04 O2
C2H6+3.5O2->3H2O+2CO2
0.27 C3H8
1.35 O2
C3H8+5O2->4H2O+3CO2
Energy value LNG: 10.75 kWh/Nm3
Density LNG: 0.784 kg/Nm3
Density oxygen: 1.429 kg/Nm3
Combustion of 1 Nm3 natural gas
Sum. Oxygen
95.81 molar/Nm3
Oxygen-fuel ratio: 95.81*32 = 3.0659 kg/Nm3 LNG
Stoichiometric oxygen needed: 3.0659/0.01075 = 285.2 kg/MWh
Oxygen needed for conversion from WRD-Oil to LNG
Estimated excess oxygen for LNG combustion: 1.6 %
Pure oxygen used for WRD-oil combustion: 17 775 050 Nm3
Stoichiometric oxygen use WRD-oil: 0.9756*17775050 = 17 341 339 Nm3
Oxygen needed conversion from oil to LNG: 17 341 339*(1.022*1.016) = 18 006 414 Nm3
Oxygen needed for conversion from LPG to LNG
Estimated excess oxygen for LNG combustion: 1.6 %
Pure oxygen used for LPG combustion (converter excluded): 7 083 840 Nm3
Stoichiometric oxygen use LPG: 0.984*7083840 = 6 970 499 Nm3
Oxygen needed conversion from LPG to LNG: 6 970 499(1.006*1.016)=7 124 519 Nm3
Total oxygen difference:
18 006 414 + 7 124 519 - 17 775 050 - 7 083 840 = 272 043 Nm3
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Flue gas calculations LPG
Combustion of 1 kg LPG with oxygen (1.6 % excess)
21.54 C3H8 + 0.86 C4H10 + 115.103 O2 -> 68.06 CO2 + 90.46 H2O + 1.813 O2
Theoretical flue gas amounts (mol/kg)
CO2
68.06
H2O
90.46
O2
1.813
Flue gas per energy input (mol/kWh)
Energy value LPG per ton: 46.05 GJ/ton = 12791.67 kWh/ton
CO2
5.321
H2O
7.072
O2
0.142
Sum
12.535
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Flue gas calculations WRD-oil
Combustion of 1 kg WRD-oil with oxygen (2.44 % excess)
72.373 C + 64.356 H2 + 0.012 S + 0.011 N2 + 0.006 H20 + 107.11 O2 ->
-> 72.373 CO2 + 64.356 H20 + 0.012 SO2 + 0.011 N2 + 2.55 O2
Theoretical flue gas amounts (mol/kg)
CO2
H2O
SO2
N2
O2
72.373
64.356
0.012
0.011
2.55
Flue gas per energy input (mol/kWh)
Energy value WRD-Oil per m3: 38.16 GJ
Approximated density: 883 kg/m3
Energy value WRD-Oil per kg: 38.16 GJ/0.883 = 43.22 GJ/ton = 12005.56 kWh/ton
CO2
6.03
H2O
5.36
SO2
0.001
N2
0.001
O2
0.212
Sum
11.60
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Flue gas calculations LNG
Combustion of 1 Nm3 natural gas with oxygen (1.6 % excess)
40.21 CH4 + 4.01 C2H6 + 0.27 C3H8 + 0.15 N2 + 97.34 O2-> 49.04 CO2 + 93.53 H2O + 0.15 N2 + 1.53 O2
Theoretical flue gas amounts (mol/Nm3)
CO2
49.04
H2O
93.53
N2
0.15
O2
1.53
Flue gas per energy input (mol/kWh)
Energy value LNG per Nm3: 38.69 MJ = 10.75 kWh/m3
CO2
4.562
H2O
8.700
N2
0.014
O2
0.142
Sum
13.418
Attachment 3 – Energy use and emissions of the burner installations today
Continues Casting
LPG Burner
installation
Casting
Dryer 1
Power Demand
[MW]
Total Power Demand
[MW]
Consumption 2012
[MWh]
Total Consumption
2012 [MWh]
Approximate Carbon
Dioxide emissions
[tons]
2.5
2.5
Power Demand
[MW]
Total Power Demand
[MW]
Consumption 2012
[MWh]
Total Consumption
2012 MWh
Approximate Carbon
Dioxide emissions
[tons]
Measured NOx
emissions [Tons]
Approximate SO2
emissions [tons]
Approximate dust
emissions [tons]
Oxygen use [Nm3]
0.2
0.2
0.7
0.7
Pre-heater
Converter
4
Hot Rolling Mill
Mapeko Mapeko
Converter
east
west
Aga elti
heater
Mefkon 1 Mefkon 2
2
2
2
2
6.8
700
700
60
60
500
500
165
165
13
13
120
120
EAF
15.8
Coil
Coil
Furnace 1 Furnace 2
1.7
1.7
WBF A
Acid Regeneration Plant
WBF B
66
28
6 400
3 300
4 900
4 900
4 900
2 520
Measured/calculated
NOx emissions [kg]
Oxygen use
(converter excluded)
[Nm3]
WRD-Oil Burner
Installation
Melt Shop
Cutting Cutting
Casting Casting pre- Casting preMachine Machine
Dryer 2 heater 1
heater 2
1
2
11 000
800
1100
1100
1100
2 600
0.7
3.2
2.6
70.2
4 000
4 000
164 000
35 400
1 500
Cutting
Machine 529CG10 529CJ20
3
500
429CE10
1.7
7.5
6 600
5 300
172 500
3 500
15 400
950
950
38 000
120
1 500
1 250
800
1800
57 500
950
950
33 000
200
3900
3200
2100
84 000
6 999 840
0
0
0
0
0
0
0
APL
District
heating for
vaporization
Vaporization station
39
Energy demand
2012 [MWh]
2354
39
102 000
102 000
28 000
35.3
42,7
0,97
17 775 050
HÖGSKOLAN I HALMSTAD • Box 823 • 301 18 Halmstad • www.hh.se
Attachment 4 – Energy use and emissions of the burner installations following a conversion to LNG
LNG Burner
installation
Casting
Dryer 1
Casting
Dryer 2
Power Demand MW
2.5
2.5
Total Power
Demand MW
Consumption
MWh
Total Consumption
MWh
New calculated
Carbon Dioxide
emissions [tons]
Measured/calculate
d new NOx
emissions [kg]
Oxygen use
(converter
excluded) [Nm3]
LNG-Burner
Installation
700
700
143
143
APL
39
39
Approximate NOx
emissions [tons]
Approximate SO2
emissions [tons]
Approximate dust
emissions [tons]
Oxygen use [Nm3]
0.2
0.7
0.7
Converter
heater
4
2
Melt Shop
Mapeko
Mapeko
east
west
Mefkon 1 Mefkon 2
2
2
Hot Rolling Mill
Aga elti
EAF
2
15.8
60
60
500
500
102 000
100 600
11
11
104
104
Coil
Coil
Furnace 1 Furnace 2
1.7
1.7
WBF A
57 MW
Acid Regeneration Plant
WBF B
66
28
6 400
3 300
4 900
4 900
4 900
2 520
Total Power
Demand [MW]
Consumption after
conversion
[MWh]
New calculated
Carbon Dioxide
emissions [tons]
0.2
Pre-heater
Converter
6.8
Power Demand
[MW]
Consumption 2012
[MWh]
Continues Casting
Casting Casting
Cutting
Cutting
prepreMachine 1 Machine 2
heater 1 heater 2
694
955
955
955
0.7
3.2
529CJ20
429CE10
2.6
1.7
70.2
11 000
4 000
4 000
164 000
35 400
1302
Cutting
529CG10
Machine 3
500
7.5
6 600
5 300
172 500
2257
3 500
15 400
825
825
32980
104
1302
1085
694
1350
43 125
713
713
33 000
150
3900
3200
2100
84 480
7 039 809
0
0
0
0
0
0
0
District
heating
Energy demand
[MWh]
District
heating
Energy demand
[MWh]
Vaporization station
3347
Reduction of Emissions
CO2 LPG
13.21 %
CO2 WRD
25.85 %
NOx LPG
28.6 %
NOx WRD
16.67 %
Oil cistern heating
0
20 261
Steam system L76
35.3
Reduction of
oil
0
Energy demand
[MWh]
1400
0
18 006 414
HÖGSKOLAN I HALMSTAD • Box 823 • 301 18 Halmstad • www.hh.se
SO2 LPG
0%
SO2 WRD
100 %
Dust LPG
0%
Dust WRD
100 %
Attachment 5 – District heating calculations
HÖGSKOLAN I HALMSTAD • Box 823 • 301 18 Halmstad • www.hh.se
Högskolan Halmstad
Magisterprogram Energiteknik
Examensarbete 15 hp
Attachment 6 – Economy calculation
Simon Bengtsson
Besöksadress: Kristian IV:s väg 3
Postadress: Box 823, 301 18 Halmstad
Telefon: 035-16 71 00
E-mail: [email protected]
www.hh.se
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