Type of CHP system: Grate fired boiler

Plant owner: VKW Kaufmann GmbH & CO KG (51% owned by Kaufmann company, 49% owned by VKW)

Commissioned: (reconstructed):1995 (2000)

Status of plant: Commercial

Contractor details: Boiler and burner: Lambion GmbH, Turbine & generator: Nadrowski (Tuthill Corp.)

Power generation: Steam turbine

The furnace systems involves an injection furnace systems and(!) a mechanically-operated biomass grate fired system.

Main fuel: Wood chips

Total annual consumption of biomass amounts to 100.000 solid m3 (70% shavings, 20% saw dust from wood processing and 10% strand.

Nominal capacities & efficiencies:

Thermal input, biomass & waste: 9,8 MW

Gross electrical output: 1,265 MWe

Net electrical output: 1,14 MWe

Electrical efficiency, gross: 12,91 %

Electrical efficiency, net: 11,63 %

Overall efficiency, gross: 82,3 %

How is plant controlled: The plant is controlled according to the amount of biomass produced.

Heat backup:

1,85 MW (built in 1985); 2,5 MW (built in 1989); 1,85 MW (built in 1993). Two older boilersystems with a combustion capacity of 4,6 MW were shut down after starting the biomass CHP unit. The peak load systems could only cover 20 to 30 % of the required heat load.

Heat usage: Heating and process steam

Energy usage: Heat is delivered to the company and the municpal center nearby. The major part is used for wood drying.

DH inlet temperature: 90 °C

DH return temperature: 70°C

Hours of full load that the heat storage can meet: 500

Fuel storage: The fuel storage has a capacity of 3000 m3 saw dust and 250 m3 wood chips

Waste water: Approx. 150 kg/h waste water.

Ash discharge: 25 kg/h ash (10% large particles, 90% fly ash)

Plant description:

The plant consists of (i) a boiler (incl. preheating and superheating system), (ii) a five stage back pressure turbine, (iii) a cyclone, (iv) an electro filter and (v) heat exchanger. The heating systems consists of a mechanically operated grate fired boiler (for the chipped coarse fuel wood) and an injection furnace system (for the fine fuel wood). Both furnaces can be operated separately or together. Goal: The plant was built in order to use the wood residues from Kaufmann’s wood processing business. The plant has been commissioned following the very stringent Vorarlberger “Luftreinhaltegesetz”.

Turbine: Back pressure turbine

Steam data: The boiler system provides 10 t/h steam to the turbine (445 C/30 bar).

Electricity sale info: The feed in rate in Austria is regulated by law and depends on the type of biomass used and on the size of the plant.

Total capital cost: € 4,500,000

Data collected and quality assured by: Austrian Energy Agency.

Contact person: Elvira Lutter