Energy self-sufficient farms which also provide energy income in all energy use categories - electricity, heat, automotive fuel and machine fuel - fulfil many targets of the European Union agricultural, energy and traffic policies. Despite EU policy support, Kalmari farm in the village of Leppävesi, 15 km from city of Jyväskylä in Central Finland is a very rare case of such a farm scale polygeneration facility. The biogas production system is a result of an individual farmer's vision and efforts in the face of the Finnish political environment that, instead of granting support, maintains many barriers to such activities. Ari Lampinen, University of Jyväskylä, Finland describes the system.
Erkki Kalmari's farm is an old family farm where a self-designed and self-constructed biogas reactor system has been in operation since 1998, originally producing electricity, heat and fertilizers, and since 2002 engine fuel as well. The mesophilic anaerobic fermentation reactor co-digests cow manure, food industry waste, kitchen waste and plant waste. The farm is currently self-sufficient in electricity, heat and automotive fuel and is generating extra income by selling electricity to the grid. Automotive fuel sales are scheduled to commence in 2005.
The biogas system overview is shown in the Figure 1 and Figure 2. The main feedstock for the reactor originates from 40 cows and 60 calves in an open cow house (A) where the animals are not tied but free to move around. The raw sludge is stored in a closed intermediate storage (B) facility. Biowaste storage building (C) contains waste from the local food industry (sweet factory), kitchen waste from the farm and plant waste from the farm. Cow sludge and biowaste are mixed in a 90 m3 mixer tank (D). The mixer tank is behind the biowaste storage building but is not visible in the aerial photo. The raw mixed sludge is pumped into a 150 m3 biogas reactor (E). The reactor is kept at a constant temperature of about 35°C that is optimal for mesophilic bacteria catalysing the anaerobic digestion process that produces biogas and fermentation residue. The reactor also acts as intermediate biogas storage. Process control and monitoring electronics as well as CHP unit and gas boiler are located in building (F) where the produced raw biogas is pumped. Hydrogen sulphide is removed from the gas biologically inside the reactor and water by absorption immediately after the reactor. The resulting gas contains about 60–65% methane and 35–40% carbon dioxide. For automotive fuel use the biogas is upgraded by water scrubbing in a container (G) to 200 bar 98% methane.
Full-size image (56 K)
Energy self-sufficient farms which also provide energy income in all energy use categories - electricity, heat, automotive fuel and machine fuel - fulfil many targets of the European Union agricultural, energy and traffic policies. Despite EU policy support, Kalmari farm in the village of Leppävesi, 15 km from city of Jyväskylä in Central Finland is a very rare case of such a farm scale polygeneration facility. The biogas production system is a result of an individual farmer's vision and efforts in the face of the Finnish political environment that, instead of granting support, maintains many barriers to such activities. Ari Lampinen, University of Jyväskylä, Finland describes the system.
Erkki Kalmari's farm is an old family farm where a self-designed and self-constructed biogas reactor system has been in operation since 1998, originally producing electricity, heat and fertilizers, and since 2002 engine fuel as well. The mesophilic anaerobic fermentation reactor co-digests cow manure, food industry waste, kitchen waste and plant waste. The farm is currently self-sufficient in electricity, heat and automotive fuel and is generating extra income by selling electricity to the grid. Automotive fuel sales are scheduled to commence in 2005.
The biogas system overview is shown in the Figure 1 and Figure 2. The main feedstock for the reactor originates from 40 cows and 60 calves in an open cow house (A) where the animals are not tied but free to move around. The raw sludge is stored in a closed intermediate storage (B) facility. Biowaste storage building (C) contains waste from the local food industry (sweet factory), kitchen waste from the farm and plant waste from the farm. Cow sludge and biowaste are mixed in a 90 m3 mixer tank (D). The mixer tank is behind the biowaste storage building but is not visible in the aerial photo. The raw mixed sludge is pumped into a 150 m3 biogas reactor (E). The reactor is kept at a constant temperature of about 35°C that is optimal for mesophilic bacteria catalysing the anaerobic digestion process that produces biogas and fermentation residue. The reactor also acts as intermediate biogas storage. Process control and monitoring electronics as well as CHP unit and gas boiler are located in building (F) where the produced raw biogas is pumped. Hydrogen sulphide is removed from the gas biologically inside the reactor and water by absorption immediately after the reactor. The resulting gas contains about 60–65% methane and 35–40% carbon dioxide. For automotive fuel use the biogas is upgraded by water scrubbing in a container (G) to 200 bar 98% methane.
Full-size image (56 K)
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