The Process

The preparation of the bio-input takes place in the digester plant, where the organic material is collected in a primary tank, and processed and prepared for the delivery to the digester tank.

  1. Digester tank: the anaerobic fermentation of the prepared bio-input
  2. Gas bag: biogas produced in the digester tank is collected in the flexible gas storage tank to ensure continuous supply of biogas, independent of fluctuations in the biogas production.
  3. Flare: for safety reasons, the installation of a gas flare is recommended so that excess gas can be burned off in the event of excessive gas production
  4. Auxiliary equipment: switches the flare on/off in case the biogas quantity increases or drops, or when the CHP unit is switched off for example for annual maintenance or repair
  5. Heating water: cold water is transferred from the digestion plant and other buildings into the CHP unit. Here the heat recovery system takes the ‘waste heat’ from the engine jacket and/or from the exhaust gas to heat up the water. This thermal energy can be used to heat the digester of to offset the heat requirements of the treatment plant or can be sold to local buildings.
  6. Biogas connection: the biogas is transferred from the gas bag into the CHP unit
  7. Natural gas: as an option natural gas can be connected to the system to provide additional electrical energy or heat if required (separate power unit).
  8. Engine: a range of 6 to 20-cylinder turbo charged reciprocating engines, in sizes from 165kW to 2MW are available for biogas applications. The engine is fully integrated with the digestion plant and can be controlled and monitored from anywhere on the plant, it also has the ENER·G Gkontrol system for remote monitoring and fault diagnosis.
  9. Alternator: electric generator powered by the engine that produces alternating current
  10. Silencer: reduces the engine’s exhaust gas noise. The engine is hosted in a fully noise proof container therefore the system can be applied in noise-sensitive locations.
  11. Radiator: cools the engine by transferring heat from the engine
  12. Ventilator: helps avoid overheating of the engine by providing reduction in short-circuit air flow from the pressure side to the suction side of the ventilation radial fan.
  13. Transformer: transfers electrical energy from the alternator to the (HV) cable
  14. Electricity HV cable: the electrical energy generated by the CHP unit can be utilized for the treatment plant as well as to supply the public power grid and sold as renewable electricity.
  15. Exhaust: the engine exhaust emissions are fully compliant with EU standards.
    Post-treatment of the residual digest material takes place and the end product from the fermentation of the biomass can be utilized as fertilizer.

© ENER-G 2009