GAS TURBINE COOLING SYSTEM, COAL GASIFICATION HYBRID POWER SYSTEM, AND GAS TURBINE COOLING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a gas turbine cooling system, a coal gasification hybrid power system, and a gas turbine cooling method that can efficiently cool a gas turbine with steam, without making a waste heat boiler to sacrifice generation of high pressure steam in order to increase the generation of medium pressure steam.SOLUTION: A gas turbine cooling system includes a high pressure steam pipe 28 and a medium pressure steam pipe that supply high pressure steam and medium pressure steam to a cooling system 8 of a gas turbine 3 from a high pressure system 6 and a medium pressure system 7 of a waste heat boiler 2 respectively, and a SGC steam pipe 24 that supplies steam to the cooling system 8 of the gas turbine 3 from a gasification furnace SGC 20 to generate steam by heat exchanging in a coal gasification furnace. Steam for cooling to be supplied to the cooling system 8 is selected based on the pressure of each steam, and selected steam for cooling is supplied to the cooling system 8.