Type of CHP system: Grate fired boiler

Plant owner:

Owned by

KARA I/S

Håndværkervej 70

DK-4000 Roskilde

Denmark

Phone: +45 4634 7500

Fax: +45 4634 7510

www.kara.dk

Commissioned: 1999

Status of plant: Commercial

Power generation: Steam turbine

The capacity of the boiler line is 20 tons per hour (480 tons per day).

The boiler is designed for a heating value of 11.9 GJ/ton.

The steam properties are 400 deg. C at 40 bar pressure.

Main fuel: MSW

The municipal solid waste processed origins from the neighbouring municipalities.

In 2001 the incineration plant processed 180.000 tonnes of MSW in the three boiler lines.

The fuel mix consists of 40% household waste and 60% industrial waste.

Nominal capacities & efficiencies:

Thermal input, biomass & waste: 66 MW

Total thermal input, incl. fossil fuels: 66 MW

Gross electrical output: 13,9 MWe

Net electrical output: 13,9 MWe

Heat output: 41,5 MJ/s

Electrical efficiency, gross: 21,1 %

Overall efficiency, gross: 86 %

How is plant controlled: The plant is controlled by the amount of MSW and limited by the heat demand in the surrounding district heating network.

Heat backup:

Apart from boiler line 5, the plant consists of two other boiler lines – 3 from 1981 and 4 from 1989 – designed for heat production only. The lines hold a capacity of each 15,6 MW at 110 deg.C and 6 bar and are used as stand by capacity for incenneration of waste.

The plant is connected to the large VEKS district heating network west of Copenhagen, which is again connected to the large CTR district heating network covering the major part of Copenhagen. CTR is supplied by a number of large CHP plants and local heating plants  around Copenhagen.

Heat usage: Heating only

Energy usage:

The electricity generated is sold to the grid and the heat is sold to the district heating company VEKS A/S, which supplies heat in Roskilde and surrounding municipalities and is connected to the large DH-network in the Copenhagen area (CTR)

DH inlet temperature: 100 °C

DH return temperature: 48°C

Heat storage size: None m3

Hours of full load that the heat storage can meet: 0

Fuel storage: Storage capacity: 4000 t, equals operation for 8 days

Waste water:

Waste water is led to the municipal treatment plant. In 2001 the plant (three lines) generated 20,537 m3 of waste water corresponding to 114 liter per ton waste processed.

Ash discharge: The plant produces slag, ash and residues from the flue gas cleaning.

In 2001 the residues amounted to: Slag/ash: 40,853 tons of which 28,141 tons has been recycled

Flue gas cleaning: 5,749 tons

After the grate, the slag falls into a water bath, where it is cooled and dust emission is prevented.

The fly ash and dry parts of the flue gas cleaning is sent to Germany for recycling.

Plant description:

Roskilde Incineration Plant, Line 5  is one of the most advanced incineration plants in Denmark.

The aim of the plant is to dispose of domestic and industrial waste, retrieving the energy content in the waste.

The plant is owned by the waste cooperation company KARA, which is owned by the 11 surrounding municipalities in Roskilde County.

Fuel feeding system:

The MSW fuel is transported to the plant by truck. The fuel is weighed and unloaded into the fuel silo in a closed hall, where the trucks can be unloaded without contaminating the surroundings with dust and odours. The exhaust air from the hall is used af combustion air in the boilers. The fuel is taken by grab to a funnel, from which is is led into the boiler.

Boiler: Boiler with upper drum, 86 % efficency

Turbine: 14 wheel turbine

Steam data:

Steam pressure: 40 bar

Steam temperature: 400 deg. C

Before turbine: 40 bars, 400 deg. C

After turbine: 1.1 bars and 104 deg. C

Flue gas cleaning:

Line 5 is equipped with a wet flue gas cleaning system. The system consists of an electrostatic precipitator, a quench (cooler), a HCl scrubber, a SO2 scrubber and a bag filter for dioxin cleaning.

For 2001 the emissions of environmental harmful matter and trace metals was far below the allowed limits.

In the design of the flue gas cleaning system, the focus has been on dioxin in order to ensure, that the plant will meet the dioxin emission demands which will apply in the EU in 2005.

Cooling system: The steam cycle is cooled by the district heating return water.

Staff: 3 persons day and night

Electricity sale info: Electricity is settled according to 3 tarifs – low, high and peak load.

Data collected and quality assured by: FORCE Technology.

Contact person: Anders Evald