Abstract: A combined cycle power plant startup system is provided. The system includes a steam turbine, a HRSG, a condenser, and a bypass system. The steam turbine may include a turbine section. The HRSG may be operably connected to the steam turbine for providing steam to the steam turbine. The HRSG may include a reheater. The bypass system may be configured to adjust the steam pressure downstream of the reheater by routing steam downstream of the reheater to the condenser. The bypass system may include at least one bypass line, at least one control valve operably connected to the at least one bypass line, a pressure gauge configured to monitor the steam pressure downstream of the reheater, and a controller configured to communicate with the pressure gauge and operate the at least one control valve.

Abstract: In certain embodiments, a system includes a fuel heater. The fuel heater includes a first heat exchanger configured to receive compressed air from a compressor and to transfer heat from the compressed air to a cooled intermediate heat transfer media to generate a heated intermediate heat transfer media. The fuel heater also includes a second heat exchanger configured to receive the heated intermediate heat transfer media from the first heat exchanger and to transfer heat from the heated intermediate heat transfer media to a fuel. The first heat exchanger is configured to receive the cooled intermediate heat transfer media from the second heat exchanger.

Abstract: A method controls at least a portion of a combined cycle power plant having at least one gas turbine, at least one heat recovery steam generator, and at least one steam turbine. The method includes developing an actual operating curve of a steam characteristic of the at least one heat recovery steam generator versus an amount of steam provided to the at least one steam turbine from the at least one heat recovery steam generator. The method also includes determining the steam characteristic of the at least one heat recovery steam generator at a point in time during operation of the combined cycle power plant. The method further includes providing an amount of the steam from the at least one heat recovery steam generator to the at least one steam turbine depending upon the determined steam characteristic of the at least one heat recovery steam generator at the point in time.

Abstract: In certain embodiments, a system includes a fuel heater. The fuel heater includes a first heat exchanger configured to receive compressed air from a compressor and to transfer heat from the compressed air to feedwater. The fuel heater also includes a second heat exchanger configured to receive heated feedwater from the first heat exchanger and to transfer heat from the heated feedwater to a fuel.

Abstract: A combined cycle power plant includes a gas turbomachine, a steam turbomachine operatively coupled to the gas turbomachine, and a heat recovery steam generator operatively coupled to the gas turbomachine and the steam turbomachine. The heat recovery steam generator includes a high pressure reheat section provided with at least one high pressure superheater and at least one reheater. The combined cycle power plant further includes a controller operatively connected to the gas turbomachine, the steam turbomachine and the heat recovery steam generator. The controller is selectively activated to initiate a flow of steam through the heat recovery steam generator following shutdown of the gas turbomachine to lower a temperature of at least one of the high pressure superheater and the at least one reheater and reduce development of condensate quench effects during HRSG purge of a combined cycle power plant shutdown.

Abstract: A combined cycle power plant includes a gas turbine, a steam turbine, a generator coupled to the gas turbine and a generator coupled to the steam turbine, and an auxiliary boiler operatively coupled to the steam turbine. The power plant is continuously operated in a combined cycle mode during operating of the gas turbine by starting the steam turbine first.

Abstract: A system for thermal management of exhaust gas includes: a nozzle configured to be disposed in fluid communication with an exhaust of a turbomachine; a mixing conduit in fluid communication with the nozzle; at least one secondary inlet disposed around a periphery of the nozzle and extending between an exterior of the mixing conduit and an interior of the mixing conduit; a variable nozzle mechanism configured to be movable between i) a first position in which the mechanism is configured to close the at least one secondary inlet and ii) a second position in which the mechanism is configured to open the at least one secondary inlet and adjust a selected diameter of the nozzle; and an actuator configured to move the variable nozzle mechanism between the first position and the second position.