Steam cooling apparatus for gas turbine

摘要

An apparatus and method for steam cooling a gas turbine. An intermediate-pressure drum 106 of a recovery boiler supplies outlet steam, as a cooling steam, to a combustor 117 through a steam channel 116. The flow rate of steam guided into the combustor 117 is adjusted through opening or closing of a first flow control valve 120 by a controller 125 such that the pressure of the intermediate-pressure drum 106 becomes a set value set according to a load status of a gas turbine 101. A required amount of steam according to the load status of the gas turbine 101 is fed to the combustor 117. Thus. the flow rate of steam guided into the combustor 117 is controlled by adjustment of the existing first flow control valve 120 for maintaining the pressure of the intermediate-pressure drum 106 in a predetermined state, without the need to provide an expensive valve device in the steam channel 116.