Flow Measurement and Analysis of Biogas

Biogas are called all gases, are formed by microbial degradation of organic substances under anoxic conditions (in an oxygen-free environment). These include beside digester gas and gases from landfills also the classical green gas, formed by fermentation of biological waste, food leftovers, farm manures, plant remains and energy crops (renewable raw materials).

Biogas can be used energetically either for heat production and/or energy production. All kind of biogases improve the ecobalance and have a significant share of total generation of electric energy.

Improvement of biogas formation is possible only, if data from process and produced amount of biogas are in all times available. Therefore a precise and reliable measurement of biogas flow rate and composition of the gas is recommended to use to monitor the process (analysis). Problems in the process can be recognized and measures can be taken early.

However, particularly challenges are posed to the sensor and long-term stability, because biogas is a humid and corrosive gas, gas composition is not fixed, different raw materials and process conditions leed to a different biogas composition.

Batch process related fluctuations (solid waste treatment / composting plant) or increasing age of landfills leed to another challenge: accuracy of flow reading can become worse if methane concentration is changing a lot, flow signal must be compensated accordingly, if accuracy is important for process control.