Abstract: In a method for operating a gas turbo group, partial streams of compressed air are cooled in cooling air coolers and are used as cooling air for thermally highly stressed components of the gas turbo group. The cooling air coolers are constructed as steam generators. Steam generated in the cooling air coolers is fed in part to the gas turbo group and is expanded there while providing usable power, while another part of the steam is fed into the cooling system, where the steam displaces air, which air then becomes available again to the gas turbine process. In this way, the steam generated with the help of heat removed from the cooling air is re-used.

Abstract: In a method for operating a combined cycle power plant (15) with at least two power plant units (16A, . . . , 16D), each of which includes a water/steam cycle, an accelerated start-up is achieved in a simple manner by removing a heat-transporting fluid from another operating power plant unit and using it for the preheating and/or maintaining of the heat of individual components of the water/steam cycle in one of the power plant units (16A, . . . , 16D).

Abstract: In a method for operating a combination power plant (15) with at least two power plant units (16A, . . . , 16D), each of which comprises a water/steam cycle, an accelerated start-up is achieved in a simple manner by removing a heat-transporting fluid from another operating power plant unit and using it for the preheating and/or maintaining of the heat of individual components of the water/steam cycle in one of the power plant units (16A, . . . , 16D).

Abstract: A combined-cycle power plant (1) having a gas turbine (2) has a heat-recovery system in which the exhaust gases are directed from the gas turbine (2) into a heat-recovery boiler (6), where their waste heat is used for preheating water from a water or water/steam circuit. Some of the water preheated there is used for preheating fuel for the gas turbine (2). To this end, it flows through a single circuit, the water being extracted from any desired pressure region of the heat-recovery boiler (6) via an extraction line (30, 40) and being fed to a double-tube heat exchanger (31). The fuel for the gas turbine (2) flows in the inner tubes of the double tubes (32) of the heat exchanger (31) and is heated by the preheated water, which flows around the outer tubes. Finally, the water is returned via a return line (35) to the water or water/steam circuit. The preheating by a single circuit makes possible an increased efficiency of the heat recovery.

Abstract: In some operating states, supplemental additional sealing steam must be fed to the sealing-steam system of a steam turbine. The feeding of supplemental sealing steam from the live-steam line involves considerable problems. According to the invention, therefore, the sealing-steam system is connected via a feeder line to a bleed point of the superheater of the boiler, so that the temperature of the supplemental sealing steam is well below the live-steam data and, in particular, is compatible with the material temperature in the region of the high-pressure shaft seal.