Abstract: A method for operating a gas and steam turbine system, in which, in an associated waste-heat steam generator, the heat contained in the expanded working medium of an associated gas turbine is utilized for the generation of steam for an associated steam turbine with at least one low-pressure part and one high-pressure part, the low-pressure part being assigned in the waste-heat steam generator a low-pressure stage with a low-pressure drum, gases dissolved in the water or steam being degassed essentially of steam for the low-pressure part from the low-pressure drum, and, to regulate degassing, steam production in the low-pressure drum being varied in that heat is displaced inside the waste-heat steam generator, the heat in the waste-heat steam generator being displaced in that less heat is extracted from the working medium in a medium-pressure stage or high-pressure stage of the gas and steam turbine system.

Abstract: A heat recovery steam generator is provided. The heat recovery steam generator includes an exhaust gas inlet for receiving an exhaust gas from a gas turbine. A first superheater is positioned in a flow direction of the exhaust gas. A heating surface is disposed between the exhaust gas inlet and the first superheater. A separator is connected downstream of the heating surface on a secondary side of the heating surface.

Abstract: Disclosed is a gas and steam turbine plant comprising a cooling system which is configured such that said cooling system is suitable for each operational state and cools cooling air that is bled from the compressed air, and a heat exchanger system which is mounted on the primary side of a cooling air duct that branches off the compressed air duct. Said heat exchanger system transmits heat that is transported in the cooling air to a flow of combustible gas which is fed to the combustion chamber of the gas turbine.

Abstract: A combined-cycle power plant includes a steam turbine having at least one low-pressure stage and a high-pressure stage, a feed-water preheater associated with the high-pressure stage, a bypass line connected in parallel with the feed-water preheater, a gas turbine operable with both gas and oil as fuel and having a flue-gas side, and a waste-heat steam generator disposed downstream of the gas turbine on the flue-gas side for generating steam for the steam turbine.

Abstract: A steam generator, in particular a waste-heat steam generator, includes first and second evaporator heating surfaces located in an elongate gas flue for hot gas. A first supply line for feed water is throughflow-connected on an inlet side to the first evaporator heating surface, while the second evaporator heating surface is throughflow-connected on an inlet and an outlet side to a low-pressure drum. The low-pressure drum is provided with a second supply line for feed water. The first supply line has a first treatment point and the second supply line a second treatment point. Each of the treatment points serves for adding and/or extracting chemicals for water treatment, so that each evaporator heating surface can receive only feed water which is conditioned according to regulations applying to that evaporator heating surface. A method for operating the steam generator is also provided.

Abstract: A combined-cycle power plant includes a steam turbine having at least one low-pressure stage and a high-pressure stage, a feed-water preheater associated with the high-pressure stage, a bypass line connected in parallel with the feed-water preheater, a gas turbine operable with both gas and oil as fuel and having a flue-gas side, and a waste-heat steam generator disposed downstream of the gas turbine on the flue-gas side for generating steam for the steam turbine.

Abstract: A method for operating a combined-cycle power plant includes utilizing heat contained in an expanded working medium of an associated gas turbine operable with both gas and oil as fuel, to generate steam for an associated steam turbine having at least one high-pressure stage. After a change of the operation of the gas turbine from gas to oil, feed water to be supplied to the high-pressure stage is divided into a first and a second partial stream, and only one of the partial streams is preheated. Particularly high plant efficiency may be achieved with the method, irrespective of the fuel being used for the gas turbine, at a low outlay in terms of apparatus and operational requirements. A combined-cycle power plant that is particularly suitable for carrying out the method includes a bypass line connected in parallel with a feed-water preheater associated with the high-pressure stage.

Abstract: For achieving a high plant efficiency, a waste-heat steam generator, in particular for a combined-cycle power plant, has a number of heating surfaces heatable by a flue gas and carrying a medium to be heated. The steam generator can be operated at critical or supercritical pressures and has a once-through evaporator connected in countercurrent to the flue gas provided on a medium side. The evaporator is followed by a preheater and preceded by a superheater on a flue-gas side.