1. Gas analysis and gas flow measurement in a biogas plant
Energy from Biomass and Biogas
Gas analysis and gas flow measurement in a biogas plant
Ho Chi Minh City, 16 September 2013

2. 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

3. Binder Group www.bindergroup.info Binder Group AG Finance Holding
Binder Engineering GmbH Sales & Service Companies in DE / F / CH / NL / B / Singapore, China
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
BETA B.V. Manufacturing Company for Pressure and Temperature Switches

4. BINDER Gas flow measurement

5. BINDER Gas analysis

6. 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.

7. 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

8. 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

9. 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

10. Typical challenges and solutions
biogas has a high percentage of water vapour (at the top of the digester 100% relative humidity)
Humidity correction by either
1. Temperature Method
2. Dew-Point Method

11. Humidity Correction
1. Temperature Method
Based 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 Method
Using 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.

12. 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

13. Questions / Remarks?
We are happy to receive your feedback, questions and remarks.
Jan Talkenberger
Manager International Sales
Binder GmbH
Buchbrunnenweg 18
89081 Ulm, Germany
Eddy Eng
Manager South East Asia
Binder Instrumentation Pte. Ltd
25 International Business Park,
# German Centre
Singapore