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 www.usa.siemens.com/processanalytics 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 network. 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 level. 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. 2 • 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 damaged. 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 maintenance. 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 % 1% 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 availability • Industry-compatible, extremely rugged mechanical and electrical design • High service life of the H2S‑ sensor; no dilution or backflushing required • 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) report • Highly selective multi-layer detector measurement of CH4 in addition to CO2 in an NDIR measuring cell Basic configuration 1 Basic equipment for wall or rack mounting including flame arrestor X 2 Gas connections: 6 mm or 1/4 inch X 3 Gas cooling: without, Peltier cooler X 4 Enclosure design: not heated or electrically heated X 5 Pump version: without, internal in analyzer, or external X 6 Power supply: 100 V ... 120 V or 200 ... 240 V AC, in each case 47 ... 63 Hz X 7 Measuring components and measuring ranges: see text X 8 Oxygen measurement: with or without O2 sensor X Optional additional modules 9 H2S measurement: with or without H2S sensor X 10 Documentation: German, English or French X 11 Heated sample gas line, self-regulating, Ex‑proof, 5 ... 35 m X 12 Sample stream switchover for up to 4 streams X 13 LEL sensor for leak monitoring in the measuring system (alarm threshold methane) X Configuration scheme of the Set BGA Simultaneous determination of concentration. of up to four gas components (without dilution) Component Minimum measuring range Maximum measuring range Sensors CO2 0 ... 20 % 0 ... 100 % NDIR measuring cell CH4 0 ... 20 % 0 ... 100 % NDIR measuring cell O2 0 ... 5 % 0 ... 25 % Electrochemical sensor H 2S 0 ... 500 ppm 0 ... 5 000 ppm Electrochemical sensor Simple integration into process systems • Open interface architecture including fieldbus (optional) Set BGA measuring system Two-stream sample preparation 3 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 IP54 Installation site Indoor /outdoor (configurable) Cabinet conditioning Ventilator Measured components / measuring ranges • 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 Email: ProcessAnalytics.Industry@siemens.com Siemens Industry, Inc. 3333 Old Milton Parkway Alpharetta, GA 30005 800-241-4453 firstname.lastname@example.org www.usa.siemens.com/processanalytics Subject to change without prior notice PIABR-00013-0911 Printed in USA All rights reserved © 2011 Siemens Industry, Inc. 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