COMBINED CYCLE POWER PLANT HAVING IMPROVED COOLING AND METHOD OF OPERATION THEREOF

摘要

An improved combined cycle power plant (10) having a plurality of kettle boilers (30,31,32) used in sequence for cooling the compressed air being directed via line (29) to cool portions of the gas turbine (20). The kettle boilers remove heat from the compressed air and produce a plurality of steam flows in lines (70,71,73) at pressures in parallel with the heat recovery steam generator (41,42,43) steam flows. Steam in line (72) for cooling other portions of the gas turbine is maintained at a very high level of purity by providing a high rate of blowdown through line (65) from the steam drum (45) providing the steam. Heat from the blowdown flow is directed to heat exchanger (66) to heat incoming fuel gas from source (26), or alternatively to heat the condensate via line (74) during periods of fuel oil operation.