| 摘要 |
<p>In a method of operating a combined cycle system including a gas turbine (14), a steam turbine (22,24) and a multi-pressure heat recovery steam generator, an improvement includes supplying (90,74) gas turbine cooling duty steam from a high pressure section (22) of the steam turbine and from an intermediate pressure evaporator (46) in the multi-pressure heat recovery steam generator, conducting the gas turbine cooling duty steam to the gas turbine for cooling hot gas turbine parts, and then returning the gas turbine cooling duty steam to an intermediate pressure section (24) of the steam turbine. In a start-up procedure, steam is extracted from a first pass (52) of a high pressure superheater (52,54,58) in the multi-pressure heat recovery steam generator, mixed with steam discharged from the high pressure superheater (58) and then supplied to the gas turbine cooling duty system. In this same start-up procedure, the gas turbine cooling duty steam is returned to the system condenser, bypassing the intermediate pressure section of the steam turbine. Related apparatus is also disclosed. <IMAGE></p> |
