4. THE BOILERS Copenhill has two boilers - each can produce up to 137 tons of steam pr. hour. The ovens are built together with their own boiler, so that the hot smoke from the oven rises up and transfers its energy directly to the water in the pipes. The steam has a pressure of 69 bar and temp. of 440OC. Steam from both boilers is collected in a common steam pipe, called steam rail, from which the steam is passed on to the steam turbine. In order for both ovens and boilers to expand when they get hot, they are not on the floor, but are instead hung up in the steel structure, in the ceiling. 90% of the energy in the waste is converted into high-pressure steam.
3. THE OVEN SYSTEM Copenhill’s two identical incinerators each have a capacity of 25-35 tons of waste per hour. When the waste is filled into the in-the-firing tunnel, it falls through the waste shaft. Here it forms an airtight stopper, so that there is always pressure in the oven. As the waste moves forward, it gradually ignites. It takes 1.5-2 hours to burn the waste in the oven at a temperature of 950-1,100OC. The temperature is controlled by blowing air through the holes in the grates. Once the waste has come to the end of the grate, virtually all energy is released like hot smoke. For each ton of waste, Copenhill can produce 2.7 MWh of district heating (DH) and 0.8 MWh of power.
1. WASTE ARRIVES Receives residual waste from approxi- mately 600,000 citizens and 68,000 businesses. There are 250-300 lorries with waste to be weighed and recorded every day. It is investigated whether the waste has been sorted properly and that it does not contain elements that could damage the plant or that are toxic.
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2. WASTE SILO
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Waste is tipped directly into the silo, which is 30x50 meters and has a total height of 36 meters. The silo can hold about 22,000 tons of waste - that equates to about three weeks of waste. Two automatic grabs - each can lift up to 15 tons of waste - make sure to mix the waste so that it becomes fairly uniform. The homogeneity of the waste is important for the combustion process to be as stable as possible. To reduce odors from the waste, there is negative pressure in the unloading hall. The air that is sucked out of the hall is used in the ovens.
5. TURBINE AND HEAT EXCHANGER A steam turbine is connected to a generator, which converts the steam energy into electricity. Electricity production is up to 63 MW. Once the turbine has taken the pressure and heat off the steam, heat energy remains. This energy is used in the district heating (DH) exchangers. In the heat exchangers, DH water is heated, which is sent into the DH system. DH production is up to 247 MW. At Copenhill, the production of electricity and DH is flexible: If market price for electricity is high, all the steam is passed through the turbine. If, on the other hand, there is a need for a lot of DH, the steam is diverted around the turbine (by-pass) and directly into the heat exchangers.
For further information please contact: Henrik Søndergaard, hs@dbdh.dk
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