Method of obtaining a deaerated condensate of a gas and steam-turbine plant

摘要

Condensate of a combined-cycle gas and steam turbine plant is deaerated. The condensate is heated in a feedwater tank to which preheated condensate is supplied. The condensate is preheated in a waste-steam generator heated by waste heat of the gas turbine. Feedwater is extracted and warmed in heating surfaces connected in the water/steam loop of the steam turbine and heated by the exhaust gas from the gas turbine. In order to guarantee adequate deaeration of the condensate at a simultaneously high efficiency of the plant through especially high energy utilization of the waste heat from the gas turbine, a partial flow of the preheated condensate or a partial flow of preheated feedwater is used as heating medium for heating the condensate. A low-pressure economizer is connected downstream of a condensate preheater in the waste-heat steam generator via a feedwater tank. The condensate preheater or the low-pressure economizer have at their outlet an outflow line leading into the feedwater tank.