Set BGA (Bio Gas Analyzer) for Biogas

Set BGA (Bio Gas Analyzer) for Biogas
Set BGA (Bio Gas Analyzer) is a fully configured and ready-to-run gas ­analysis system for use in biogas plants. The
integrated ULTRAMAT 23 industrial gas analyzer has four measuring channels for simultaneous determination of the
relevant gas components methane, carbon dioxide, hydrogen sulfide, and oxygen. The Set BGA is especially
economical for the operator thanks to standardization. The ULTRAMAT 23, proven in decades of harsh industrial use,
features maximum performance and operational reliability.
Gas analysis in biogas plants with the
"Set BGA" complete measuring system
from Siemens
Process Analytics
Biogas – production and use
Biogas is a flammable gas used for generating energy; it is produced by fermentation of biomass under exclusion
of oxygen. Such plants can be found in
agricultural companies and also in
municipal or industrial sewage treatment plants. The materials used
include organic municipal waste,
renewable raw materials, liquid
manure. The crude biogas produced in
a first reactor (fermenter) consists of
methane and carbon dioxide as the
main components as well as hydrogen
sulfide, ammonia and water vapor (see
table “Biogas composition”). The flammable methane is the supplier of
energy. Following further treatment,
the biogas is used in combined heat
and power (CHP) plants with gas
engines to generate electricity and
heat or is fed into a natural gas
Gas analysis in biogas plants
A biogas plant must be continuously
monitored with respect to gas composition, temperature, dwell time in the
fermenter and the addition of substrate
to ensure optimum operation of the
biological process and to achieve as
high a methane yield as possible. It is
particularly important to check the
concentration of hydrogen sulfide as
this residual gas is toxic and corrosive
and can also disrupt the biological process above a specific concentration
Plant monitoring is carried out by analyzing the composition of the raw biogas downstream of the fermenter with
the following significance for the process:
• The methane concentration is used
to control the addition of material.
A fluctuating methane content in
the fermenter would considerably
disrupt the fermentation process.
• The oxygen concentration is
extremely important to ensure an
optimum fermentation process
since the formation of explosive
gas mixtures can then be detected
early and prevented.
• Measuring hydrogen sulfide levels makes it possible to keep the
concentration of this toxic and
corrosive gas as low as possible by
taking appropriate action. Besides
the risk to people resulting from
its toxicity, this gas can adversely
affect both the generation of biogas and downstream processes.
• Under the effects of humidity and
warmth, hydrogen sulfide reacts
with metal components such as
pipelines or connections. When
hydrogen sulfide is converted
to sulfur dioxide in combustion
engines, this endangers their
­operational safety and makes
more frequent oil changes necessary. The metallic heat exchanger
installed downstream can also be
If biogas is to be used in combined
heat and power (CHP) plants or particularly for feeding into a natural gas
network, certain gas qualities (the
methane content, remaining content
of carbon dioxide and contamination)
have to be achieved and maintained by
means of a downstream gas preparation system. The Siemens gas chromatograph SITRANS CV (Calorific
Value) or the complete system “Set CV”
is ideally suited to such monitoring.
Set BGA standard measuring system
Set BGA (biogas analysis, see title picture) is one of a series of standardized
complete systems for gas analysis which
Siemens Process Analytics has developed for certain fields of application.
The sets contain all the required components for the relevant application, from
gas sampling to operator control and
display units in a compact design. Sets
are easy to configure and provide
­considerable user benefits thanks to
reduced requirements for planning,
engineering, installation, training, and
The Set BGA comprises a measuring system and an optional sample preparation
device (see title picture). The Set BGA
measuring system (see Fig. “Set BGA
measuring system”) consists of the fourcomponent ULTRAMAT 23 gas analyzer
with selectable equipment and I/O components (basic equipment) as well as
additive modules (see Table
“Configuration scheme of the Set BGA”).
Efficient sample preparation (see Fig.
“Two-stream sample preparation”) for
fast, reliable and reproducible analytical
results is an essential prerequisite for
analyzing raw biogas. Up to four sample
streams can be chosen for continuous
analysis. The sample preparation device
is fitted in a rugged enclosure in which
a cabinet heater can be accommodated
(to avoid condensation moisture when
installed outdoors) in addition to a suction pump.
Gas component
Concentration range
Mean value
Methane (CH4)
45 ... 70 %
60 %
Carbon dioxide (CO2)
25 ... 55 %
35 %
Water vapor
0 ... 10 %
3 ... 10 %
Nitrogen (N2)
0.01 ... 5 %
Oxygen (O2)
0.01 ... 2 %
0.3 %
Hydrogen (H2)
0 ... 1 %
< 1 %
Ammonia (NH3)
0.01 ... 2.5 mg/m3
0.7 %
Hydrogen sulfide (H2S)
10 ... 30 000 mg/m3
< 500 mg/m3
Biogas composition
User benefits and performance features
Reduced operating and
maintenance costs
• Monitoring of several fermenters
using one device via measuring
point switchover function
• Can be ordered from catalog,
supplied ready-to-run, minimum
installation efforts
• Reduced calibration gas requirements thanks to AUTOCAL function
with ambient air
• NDIR measuring cells can be
cleaned by the user and are therefore reusable
• Excellent accessibility thanks to
arrangement in hinged bays
Particularly high operational
reliability, long-term stability and
• Industry-compatible, extremely
rugged mechanical and electrical
• High service life of the H2S‑ sensor; no dilution or backflushing
• Compensation of pressure and
temperature influences
• Self-explanatory operating text,
large display, protection against
unauthorized access
• Diagnostics functions, logbook
Particularly high measuring
accuracy and safety
• No dilution of sample gas required
• Suitable for connection of flam­
mable gases at high concentration (as is the case with biogas)
in accordance with TÜV (German
Technical Inspection Association)
• Highly selective multi-layer detector measurement of CH4 in addition
to CO2 in an NDIR measuring cell
Basic equipment for wall or rack mounting
including flame arrestor
Gas connections: 6 mm or 1/4 inch
Gas cooling: without, Peltier cooler
Enclosure design: not heated or electrically heated
Pump version: without, internal in analyzer, or
Power supply: 100 V ... 120 V or 200 ... 240 V AC,
in each case 47 ... 63 Hz
Measuring components and measuring ranges:
see text
Oxygen measurement: with or without O2 sensor
H2S measurement: with or without H2S sensor
Documentation: German, English or French
Heated sample gas line, self-regulating, Ex‑proof,
5 ... 35 m
Sample stream switchover for up to 4 streams
LEL sensor for leak monitoring in the measuring
system (alarm threshold methane)
Configuration scheme of the Set BGA
Simultaneous determination of concentration. of up to four gas components
(without dilution)
measuring range
0 ... 20 %
0 ... 100 %
NDIR measuring cell
0 ... 20 %
0 ... 100 %
NDIR measuring cell
0 ... 5 %
0 ... 25 %
Electrochemical sensor
H 2S
0 ... 500 ppm
0 ... 5 000 ppm
Electrochemical sensor
Simple integration into process
• Open interface architecture including fieldbus (optional)
Set BGA measuring system Two-stream sample preparation
Technical specifications
Ambient temperature
+ 5 ... +38 °C
Dimensions of Set BGA
measuring system (W x H x D)
600 x 781 x 600 mm
Dimensions of sample preparation
(W x H x D)
600 x 600 x 220 mm
Weight of Set BGA measuring system
50 kg
Weight of sample preparation
22 kg
Degree of protection
Installation site
Indoor /outdoor (configurable)
Cabinet conditioning
Measured components / measuring
• CH4
0 ... 100 vol% to 0 ... 20 vol% (NDIR)
• CO2
0 ... 100 vol% to 0 ... 20 vol% (NDIR)
• O2
0 ... 25 vol% to 0 ... 5 vol% (electrochemical); optional
• H2S
0 ... 5 000 vpm to 0 ... 500 vpm (electrochemical); optional
Safety switching devices
Power supply
110 V AC ± 10%, 47 ... 63 Hz
230 V AC ± 10%, 47 ... 63 Hz
Power consumption
Approx. 180 VA (without cooler and sample preparation)
Analog outputs
Per component 0/2/4 ... 20 mA; NAMUR, floating, max. load 750 Ohm
Sample preparation
Max. 4 sample streams can be controlled using Logo module with fast loop pump in separate enclosure
Permissible pressure fluctuations
• Without pump, not pressurized (< 1 200 mbar absolute); pressure reduction must be provided for
higher input pressures
• With pump, suction mode with flow by gravity
Pump performance
Adjustable to 60 ... 80 NL/h
Detonation protection F501
Flow measurement with limit monitoring at the output
Stainless steel screwed glands (outdoor installation)
LEL monitoring (optional)
For more information, please contact:
Siemens Industry, Inc.
7101 Hollister Road
Houston, TX 77040
Phone: 713-939-7400
Siemens Industry, Inc.
3333 Old Milton Parkway
Alpharetta, GA 30005
Subject to change without prior notice
Printed in USA
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© 2011 Siemens Industry, Inc.
The information provided in this brochure contains merely
general descriptions or characteristics of performance
which in case of actual use do not always apply as described
or which may change as a result of further development
of the products. An obligation to provide the respective
characteristics shall only exist if expressly agreed in the
terms of contract.
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names of Siemens AG or supplier companies whose use by
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of the owners.
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