The global warming issue calls for renewable energy sources. Biogas plants can provide electricity and heat based on biomass. Parts of the generated electricity is consumed internally. One major consumer is the agitator in the biogas digester. By monitoring the mixing quality in the digester the optimization of the agitator’s operation pattern and rotational speed can be done. Nevertheless, a lower gas production rate due to insufficient mixing has to be avoided. A computational fluid dynamic (CFD) simulation of a biogas digester was used for modelling the fluid flow in a digester. The model is validated in an experimental size digester using particle image velocity. In a field experiment, the knowledge from the physics of fluid flows are compared to fluid flow in real biogas plants. By altering the agitator parameters, an optimization of the internal energy consumption is investigated. A controller fed by measured parameters of the plant is used to control the agitator.      «

The global warming issue calls for renewable energy sources. Biogas plants can provide electricity and heat based on biomass. Parts of the generated electricity is consumed internally. One major consumer is the agitator in the biogas digester. By monitoring the mixing quality in the digester the optimization of the agitator’s operation pattern and rotational speed can be done. Nevertheless, a lower gas production rate due to insufficient mixing has to be avoided. A computational fluid dynamic (C...     »