METHOD FOR OPERATION OF A COMBINED-CYCLE POWER PLANT WITH COGENERATION, AND A COMBINED-CYCLE POWER PLANT FOR CARRYING OUT THE METHOD

摘要

The invention relates to a method for operation of a combined-cycle power plant with cogeneration, in which method combustion air is inducted in at least one gas turbine, is compressed and is supplied to at least one combustion chamber for combustion of a fuel, and the resultant exhaust gas is expanded in at least one turbine, producing work, and in which method the exhaust gas emerging from the at least one turbine is passed through a heat recovery steam generator in order to generate steam, which generator is part of a water-steam circuit with at least one steam turbine, a condenser, a feedwater tank and a feedwater pump, wherein heat is provided by extracting steam from the at least one steam turbine. In a method such as this, the electricity production is decoupled from the steam production in that in order to restrict the electricity production while the heat provided by means of steam extraction remains at a constant level, a portion of the inducted combustion air is passed through the at least one turbine to the heat recovery steam generator without being involved in the combustion of the fuel in the gas turbine, and in that this portion of the combustion air is used to operate at least one supplementary firing in the heat recovery steam generator.