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 technologyThe 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 Correction1. 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 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 Salesjan.talkenberger@bindergroup.info+49 1733069903Binder GmbHBuchbrunnenweg 1889081 Ulm, Germany

Eddy EngManager South East Asiabinder.engrg@pacific.net.sg+65 96748286Binder Instrumentation Pte. Ltd25 International Business Park,# 04-06 German CentreSingapore 609916