Type of CHP system: Grate fired boiler

Plant owner: Owner of the plant is Fernwärme Wien GmbH. Originally the plant has been built by MA 22  (municipal department in charge of environmental protection)

Commissioned: (reconstructed):1971 (1989)

Status of plant: Commercial

Contractor details:

Boiler: 30 MW, 80% efficiency, Austrian Energy & Environment; Burner: Uniterm (2 burners per boiler, each 9 MW), Turbine: Austrian Energy & Environment; generator: 8,5 MWC plant, 97,21 efficiency, Elin; storage tank: VOEST (10 hot water tanks each 157 m3); Cooling: Carrier (2 pieces, 890 kW; 765 kW)

Power generation: Steam turbine

The thermal waste treatment plant Spittelau consist of two incineration lines, each with a flue gas treatment plant, with a SCR-DeNOX and dioxin destruction facility serving both lines, and a treatment plant for the waste water arising from the flue gas scrubbing system.

Main fuel: MSW

Municipal solid waste and domestic waste similar commercial waste, 270.000 tonnes per year, average heating value: 8,8 MJ/t

Nominal capacities & efficiencies:

Thermal input, biomass & waste: 82,2 MW

Total thermal input, incl. fossil fuels: 82,2 MW

Gross electrical output: 8,5 MWe

Net electrical output: 6,8 MWe

Heat output: 62,92 MJ/s

Electrical efficiency, gross: 20 %

Overall efficiency, gross: 74 %

Power to heat ratio: 1

How is plant controlled: The plant is controlled according to steam capacity, O2-concentration, and temperature in the combustion chamber

Heat backup: Stand-by diesel aggregate for emergency current in the case of grid break down. Capacity: 800 kW

Heat usage: Heating only

Energy usage:

Averaged over the year, more than 5 MW of power for internal consumption and infeed to the public grid as well as some 60 MW of district heating energy – the space heating equivalent of approx. 15,000 80 m2 dwellings – are recovered from the waste’s energy content.

DH inlet temperature: 90-150 °C

DH return temperature: 60°C

Fuel storage: The fuel storage has a size of 7,000 m3 or 2,600 tonnes corresponding to 72 hours of operation at full load.

Waste water:

Approx. 15 m3/hour of waste water are generated amounting to a total of 112.000 m3/a. All waste water emitted by the flue gas scrubbing system is processed in a special treatment plant before being relased into the receiving water. The heavy metal compounds dissolved in the discharge water from the first scrubber are first converted to insoluble form in a precipitation reactor, by dosing lime slurry as well as special precipitation and flocculation agets. Thereafter, separation of the heavy metal hydroxide suspension thurs created takes place in the laminar clarifier which is connected in series. Following reperition of the precipitation and separation stages, the resultant hydroxide sludge is dewatered to a residual moisture content of approx. 30% in a chamber filter press and filled in big bags as filter cake.  After a final check of volumetric flow, temperature, pH value and conductivity, the cleaned waste water is passed into the receiving water. The sodium sulphate-laden discharge water from the second scrubber is processed in the multi-stage recycling plant.

Ash discharge: Residues remaining are composed of ash, slag,  dry sludge, cement and scrap metal.  The dry sludge is landfilled in a salt deposit. Sludge, Ash and cement are cemented.

Plant description:

The Thermische Abfallbehandlungsanlage Spittelau is part of the district heating plant Spittelau with an totally installed capacity of 460 MW,  the second largest heat producing unit in the heating network of Vienna.  The Thermische Abfallbehandlungsanlage Spittelau has a  throughput capacity of 250,000 tonnes per year, is integrated in the public heating network, and on the average the annual feed in amounts 60 MW (base load).  Aims are (1) waste disposal, anbd (2) heat supply for veinna (secure heat supply of the general hospital).

Fuel feeding system:

Via the furnance feed chute and hydraulic ram feeder, the waste passes from the bunker to the firing grate situated at the lower end of the furnace. Up to 18 tons of waste per hour can be thermally treated on the inclinded, 35 m2 two-track reverse-acting stoker grate.

Turbine: Saturated steam back pressure turbine, masx. Power output 6.4 MW, back pressure: 4.5 bar

Flue gas cleaning:

The thermal waste treatment plant is equipped with an electrostatic precipitator, by a 2-stage flue gas scrubber with downstream fine dust separator (electrodynamic Ventur). Today with this 3 treatment stages and Europe’s first SCR-DeNOx facility downstream to a scrubber in 1989, the plant became an international leader in flue gas cleaning.

Cooling system:

Natural circulation radiant type boiler, max. steam output per line: 50 tons/h (saturated steam). Max. operational pressure: 34 bar, Max. operational temperature: 245 °C, Effective heating surface: 2,420 m2

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.

Data collected and quality assured by: Austrian Energy Agency.

Contact person: Elvira Lutter