the biogas market is very active and is developing very rapidly. Biogas has
many uses, such as using biogas as a vehicle fuel, or using biogas to generate
electricity and heat in a cogeneration plant. For biogas production equipment, we
also need to monitor biogas flow rate, the fermentation temperature and
digesters pressure to ensure the safety and proper operations.
Purpose of biogas metering
In the process of
biogas production and usage, the main purposes of measurement biogas flow rate are
Provide reference data for biogas
stations: The purpose of installing a flow meter at a biogas supply station is
to provide basic data for the scheduling and control of biogas.
Detecting the efficiency of the
fermenter or landfill: Know the efficiency of the fermenter through the biogas
flow sensor. If the flow has unexpected fluctuations, you can check the
condition of the fermenter in time.
Control the combustion efficiency of
the boiler: When the biogas boiler is burning, it is necessary to understand
the flow rate of the biogas to control the ventilation of the boiler. If the
ventilation is too large, the furnace temperature will be lowered; if the
ventilation is too low, the gas cannot be fully burned to cause waste and
Control greenhouse gas emissions: CH4
and CO2 in biogas are greenhouse gases; CH4 is a greenhouse gas that is more
harmful than CO2.
Civil biogas metering charges:
civilian users install gas flowmeters mainly for custody transfer, management
departments for cost accounting.
Difficulties in biogas flow measurement
Biogas is a gas
that is very difficult to measure. It has the following technical characteristics:
(1) The pressure
is extremely low: the original biogas coming out of the fermenter usually does
not exceed 0.1 kg (10 kPa).
change: Biogas is composed of a variety of mixed gases, and the gas production
materials are different, and the biogas components generated may also fluctuate
fluctuations in flow: With the changes in the raw materials, bacteria,
temperature fluctuations, etc., the produced biogas flow will also vary
greatly, so the flowmeter is required to have a larger turndown ratio.
(4) Water vapor:
Biogas is produced by biomass fermentation, and the water in the biomass is brought
into the biogas, so the biogas usually contains saturated water vapor.
Biogas usually contains H2S. Although the content is low, H2S will form
corrosive hydrogen sulphate after it encounters water vapor, which has great
corrosion hazard to the metering components.
Biogas metering technology
At present, there
are several biogas flow metering technologies that have been widely used in
biogas, including thermal mass flow meters, turbine flowmeters, vortex flowmeters, orifice flowmeters,
and ultrasonic gas flowmeters. However, due to the low biogas pressure, large
changes in the flow rate of biogas components, strong corrosiveness, and
viscous impurities, these flow metering techniques also have some application
problems, which cause troubles for flow meter stability and routine
Current we often
recommend Thermal mass flow meter for biogas flow measurement due to
below prominent advantages
It does not need any external temperature
pressure and temperature compensation to have mass flow measurement.
Thermal mass flow meter has large turn
down ratio which can reach to 100:1; it can detect low biogas flow.
It can measure low pressure gas.
Gas flow sensor material is 316
stainless steel which for slightly corrosive biogas measurement.
Digital display to show instant and
total biogas flow,also for easy configurations.
4-20mA, pulse, RS485 and Hart Protocol
is intended to different control purposes.
Insertion type available for large
Instruments supply good quality and economical biogas flow meters, welcome to
contact us for more information.