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CHP power plants can be divided into five types: backpressure, extraction condensing, gas turbine heat recovery, combined cycle and reciprocating engine power plants. Backpressure power plant The simplest cogeneration power plant is the so-called backpressure power plant, where CHP electricity and heat is generated in a steam turbine. Another main component of the backpressure power plant is the steam boiler, which can be designed to fire solid, liquid or gaseous fuels. Extraction condensing power plant A condensing power plant is generating only electricity. However, in an extraction condensing power plant some part of the steam is extracted from the turbine to generate also heat. Gas turbine heat recovery boiler power plants In gas turbine heat recovery boiler power plants heat is generated with hot flue gases of the turbine. The fuel used in most cases is natural gas, oil, or a combination of these. Gas turbines can even be fired with gasified solid or liquid fuels. Combined cycle power plants Recently, natural gas fired combined cycle power plants consisting of one or more gas turbines, heat recovery boilers, and a steam turbine have become quite common. Reciprocating engine power plant Instead of a gas turbine, a reciprocating engine, such as a diesel engine, can be combined with a heat recovery boiler, which in some applications supplies steam to a steam turbine to generate both electricity and heat. |
