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Energy from Biomass and Biogas
Gas analysis and gas flow measurement in a biogas plant
Ho Chi Minh City, 16 September 2013
Gas analysis and gas flow measurement in a biogas plant
• Introduction company BINDER
• Thermal dispersion mass flow measurement
• Typical challenges and solutions
• Summary and conclusions
Binder GroupBinder Group AG Finance Holding
BINDER GmbH Manufacturing Company for Gas Flowmeter, Gas Analyzer and Control Systems with following products: COMBIMASS® / VACOMASS® / CAMASS®
INSTRUM AG Manufacturing Company for Stainless Steel Pressure Regulators and Valves
Binder Engineering GmbH Sales & Service Companies in DE / F / CH / NL / B / Singapore, China
BETA B.V. Manufacturing Company for Pressure and Temperature Switches
www.bindergroup.info
BINDER Gas flow measurement
BINDER Gas analysis
Basics of thermal dispersion technology
The principle:
Gas flows by a heated sensing element and causes cooling down of the element by the mass flow (molecules)
direct mass flow measurement, unaffected by gas pressure and temperature changes
Measurement is based on a PT 100, an additional non-heated sensor is used as a reference.
The amount is directly related to the mass flow.
Typical challenges in biogas applications
• Outdoor installation – operation for years under the sky – rain, direct sun light, snow, ...
• biogas is highly corrosive• big plants – long distances between the measuring
points• ignition potential of methane-air-mixture• the concentration of methane is changing in the biogas• biogas has a high percentage of water vapour (at the
top of the digester 100% relative humidity) and contains beside others H2S and NH3
Typical challenges and solutions
Outdoor installation – operation for years under the sky – rain, direct sun light, snow, ...
biogas is highly corrosive
Rugged stainless steel design Sensors are corrosion-proof and
resistant against moisture and dirt No mechanical moving parts
Typical challenges and solutions
The concentration of methane is changing in the biogas (e.g. density changes can cause 2…3% failure)
In combination with a gas analyser station the changing gas composition can be corrected in the flow signal
Typical challenges and solutions
biogas has a high percentage of water vapour (at the top of the digester 100% relative humidity)
Humidity correction by either1. Temperature Method2. Dew-Point Method
Humidity Correction
1. Temperature MethodBased on temperature of the biogas and assuming a relative humidity of 100% the water contents can be calculated by standard method – can be used only directly after the digester. Even if a gas cooler is used to dry the gas, directly after the gas cooler the gas is 100% water damp saturated. But gas temperature mustn't be increased due to blowers, direct sun light etc. In these cases temperature method will calculate a wrong (too high) water damp portion.
2. Dew-Point MethodUsing a special probe, the relative humidity and so the water contents can be determined. The probe is sensitive against H2S, therefore it can be used only after the filter at very low H2S-concentrations.
Summary and Conclusions Conditions in biogas plants request solid
and reliable designed products for a safe and stable operation
Thermodynamic and Chemical properties of biogas require sophisticated measurement & control equipment
Combination of gas flow and gas analyser ensures an efficient, reliable and profitable operation of the biogas plant
Questions / Remarks?We are happy to receive your feedback, questions and remarks.
Jan TalkenbergerManager International [email protected]+49 1733069903Binder GmbHBuchbrunnenweg 1889081 Ulm, Germany
Eddy EngManager South East [email protected]+65 96748286Binder Instrumentation Pte. Ltd25 International Business Park,# 04-06 German CentreSingapore 609916