Type of CHP system: CFB boiler

Plant owner: Power plant is owned by Vapo Oy

Commissioned: 1994

Status of plant: Commercial

Contractor details:

Fluidised boiler plant was commisioned by Tampella Power Oy (Kvaerner Power Oy). Fuel handling system was supplied by Vesme Oy. Valmet Automation (Metso Automation) delivered automation system for the power plant.

Power generation: Steam turbine

The boiler is a circulating fluidised bed boiler with a maximum thermal output of 30 MW. Boiler was the first CFB boiler built by Tampella Power Oy (Kvaerner Power Oy) using CYMIC circulating fluidised bed technology. The boiler tradename CYMIC comes from an abbreviation of description, CYlindrical Multi-Inlet Cyclone, given to it in the planning stage. It is a fluidised bed circulating boiler with a watercooled cyclone located inside the boiler.

Main fuel: Multifuel (more biofuels and/or peat)

The main fuels are by-products from sawmill and peat.  Total annual fuels consumption has been typically: 130 000 m3 milled peat and 100 000 m3 wood residues from a sawmill.

Nominal capacities & efficiencies:

Thermal input, biomass & waste: 34 MW

Total thermal input, incl. fossil fuels: 34 MW

Gross electrical output: 8 MWe

Net electrical output: 6,9 MWe

Heat output: 22 MJ/s

Electrical efficiency, gross: 23 %

Electrical efficiency, net: 20 %

Overall efficiency, gross: 88 %

Power to heat ratio: 0,36

How is plant controlled: By heat demand.

Heat usage: Heating and process steam

Energy usage: Process heat is used in sawmill and district heat is used in the town of Lieksa. Annual production of process heat and district heat is about 110 GWh and of electricity about 40 GWh.

District heat coverage (% of total demand in DH network): 90 %

DH inlet temperature: 85-115 °C

DH return temperature: 45-55°C

Fuel storage: Power plant has two receiving stations. One is for milled peat and another for by-products from sawmill.

Waste water: Water water from water treatment is neutralised and led to city’s sewage system. Annually about 300 m3 of waste water is generated.

Ash discharge: Ash is used as fertiliser.

Plant description:

Power plant produces process heat for the near-by sawmill and district heat for the town of Lieksa. Electricity generated by power plant is sold to clients by a local power company (Pohjois-Karjalan Sähkö Oy).

Fuel feeding system: There are two fuel silos in the boiler house. Fuel is unloaded by a screw conveyor.

Boiler: 30 MWth CFB boiler by Kvaerner Power.

Turbine: Back pressure turbine. Steam turbine is delivered by ABB (Alstom).

Steam data: 10.5  kg/s, 510°C, 61 bar (abs.)

Flue gas cleaning: The flue gases are cleaned with two box electrostatic precipitator delivered by ABB Fläkt Oy. Dust emission is below 40 mg/MJ.

Cooling system: Water from lake.

Staff: The number of operational personnel is  8.

Electricity sale info: Electricity is sold to a local power company.

Total capital cost: € 9,700,000

Cost quoted in 1994 in euros.

Data collected and quality assured by: VTT Processes.

Contact person: Kati Veijonen