| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas turbine steam cooling system for cooling the blades of a gas turbine and a high temperature cooled portion such as a tail pipe of a combustor with steam exhausted by a high pressure turbine in a combined cycle plant, without reducing the entrance pressure of a medium pressure turbine and thus decreasing combined efficiency while preventing the increase of the pressure loss of cooled steam. SOLUTION: A cooled steam temperature reducer is provided at the downstream side of a medium pressure evaporator for supply of part of high pressure exhaust through the cooled steam temperature reducer to a high temperature cooled portion, so that the high pressure exhaust can be controlled at a temperature somewhat higher than the temperature of medium pressure saturated water and desirable for cooling. Thus, a less amount of steam is required for cooling, the increase of the pressure loss of cooled steam is prevented, the entrance pressure of a medium pressure turbine is kept higher, not lower, and the expansion ratio and output in the medium pressure turbine is increased for more combined efficiency.
|
