The Biogas Process

What It Takes to Produce Power The Bio Way



Key process steps in biogas production.

Biogas is produced by the biological breakdown of organic matter in the absence of oxygen and is a type of biofuel.
Input comes in the form of renewable raw materials which are grown on an area of 220 hectares all round the plant, as well as manure (liquid) from local farmers. Specially prepared straw is added to the liquid manure stored in a mixing pit and the mixture is then pumped into a hydrolysis tank where acidification takes place.

In the two grain silos, preliminary fermentation takes place, with the long-chain polymers of the wheat and maize being split up into simpler organic compounds (they dissolve). Hydrolysis and the grain silo supply the fermenter with biomass via pipes.
In the fermenter, acetic acids which are formed are converted by micro-organisms into mainly methane and carbon dioxide. The process takes place in the mesophilic temperature range (32-42 degree C) and at a pH value of 6.8 to 7.5.
Combustible CH4 is the main component of biogas, accounting for 50 to 55 percent of the total volume. A gas analyzer with automatic measured-value acquisition (CH4, CO2, H2, O2,...) breaks the gas down into its constituents and stores them.

After being vacuum-removed from the fermenter, the gas which has accumulated in the biogas collector is cleansed of hydrogen sulphide (H2S) in a down-stream desulphurization unit, dried by means of condensation pipes and then converted into electricity in the engine-based cogeneration plant.
A spark-ignition gas engine burns the biogas thus obtained to convert it into force (movement), which in turn drives a generator.