Patent ID: 6397575
Filing Date: 2002-06-04
Classification: F01K,Y02E

Abstract:
In a combined cycle system including a gas turbine, a steam turbine and a heat recovery steam generator having a reheater and an inlet to the reheater and wherein gas turbine exhaust is used in the heat recovery steam generator for heating steam for the steam turbine, a method of operating the combined cycle system comprising the steps of:supplying steam from the intermediate pressure section of the heat recovery steam generator to the gas turbine to cool component parts thereof; supplementing the steam from the intermediate pressure section of the heat recovery steam generator by supplying a first portion of steam from a high pressure section of the steam turbine to the gas turbine to cool component parts thereof; combining spent cooling steam from said gas turbine and a second portion of steam from the high pressure section of the steam turbine; supplying the combined spent cooling steam and second steam portion to the inlet for the reheater of the heat recovery steam generator; reheating the combined spent cooling steam and said second steam portion in said reheater of said heat recovery steam generator; and flowing the reheated combined spent cooling steam and said second steam portion to an intermediate pressure section of the steam turbine.