Structure
The gas storage in the fermentation process is constructed on 2 levels.
The gas is collected in the container using a gas storage film. Another film, the weather protection film, is stretched over this gas storage film. There is a gap between these two films, which is filled with ambient air using 2 fans.
Production process
Gas production in the containers is stimulated by the temperature. Depending on the consumption of the substrate, the “used” substrate is removed from the bottom of the container and fresh material is added from above. These processes lead to an irregular biogas production process.
If the production of biogas increases, the storage volume must be released by relieving the pressure in the gap.
To remove the gas, the pressure between the storage film and the weather protection film is increased so that the gas is pushed directly into the next container. If the production of gas decreases, the pressure in the gap must also be reduced so that the gas storage film does not rest on the attachments in the container and become damaged.
The pressure increase in the roof space is achieved by switching on a second fan. The second fan is switched on or off by the hysteresis in the differential pressure measurement.
To ensure that both fans run evenly, the running times are recorded by a control system and switched alternately.