A steam turbine plant includes a high-medium pressure turbine having a high-pressure turbine section provided at one end portion in an axial direction and a medium-pressure turbine section provided at the other end portion; a low-pressure turbine disposed coaxially with the high-medium pressure turbine; a condenser configured to cool steam used in the low-pressure turbine to condense the steam into condensate; and a feed-water heater configured to heat the condensate with steam discharged from the high-pressure turbine section. The plant also includes a low-pressure moisture separating and heating device configured to remove moisture of steam discharged from the medium-pressure turbine section, and to heat the steam with a part of steam to be sent to an inlet portion of the high-pressure turbine section and a part of steam to be sent to an inlet portion of the medium-pressure turbine section from an outlet portion of the high-pressure turbine section.

A steam turbine plant includes a high-medium pressure turbine having a high-pressure turbine section provided at one end portion in an axial direction and a medium-pressure turbine section provided at the other end portion; a low-pressure turbine disposed coaxially with the high-medium pressure turbine; a condenser configured to cool steam used in the low-pressure turbine to condense the steam into condensate; and a feed-water heater configured to heat the condensate with steam discharged from the high-pressure turbine section. The plant also includes a low-pressure moisture separating and heating device configured to remove moisture of steam discharged from the medium-pressure turbine section, and to heat the steam with a part of steam to be sent to an inlet portion of the high-pressure turbine section and a part of steam to be sent to an inlet portion of the medium-pressure turbine section from an outlet portion of the high-pressure turbine section.

Disclosed herein is a supercritical CO.sub.2 generation system using plural heat sources, including: a pump configured to circulate a working fluid; plural heat exchangers configured to heat the working fluid using an external heat source; plural turbines configured to be driven by the working fluid heated by passing through the heat exchanger; and plural recuperators configured to exchange heat between the working fluid passing through the turbine and the working fluid passing through the pump to cool the working fluid passing through the turbine and heat the working fluid passing through the pump, in which the heat exchanger may include plural constrained heat exchangers having an emission regulation condition of an outlet end and plural heat exchangers without the emission regulation condition.

Disclosed herein is a supercritical CO.sub.2 generation system using plural heat sources, including: a pump configured to circulate a working fluid; plural heat exchangers configured to heat the working fluid using an external heat source; plural turbines configured to be driven by the working fluid heated by passing through the heat exchanger; and plural recuperators configured to exchange heat between the working fluid passing through the turbine and the working fluid passing through the pump to cool the working fluid passing through the turbine and heat the working fluid passing through the pump, in which the heat exchanger may include plural constrained heat exchangers having an emission regulation condition of an outlet end and plural heat exchangers without the emission regulation condition.

The once-through boiler includes a water supply and at least an economizer, an evaporator superheater. No valves are provided between the economizer, the evaporator and the superheater. The high-pressure turbine includes a control valve. The method for low load operation of a power plant with a once-through boiler and a high pressure turbine includes providing a parameter indicative of the stable operation of the once-through boiler in once-through operation, and on the basis of this parameter adjusting the control valve in order to regulate the pressure within the economizer and evaporator and/or adjusting the temperature of the water supplied to the economizer.

The once-through boiler includes a water supply and at least an economizer, an evaporator superheater. No valves are provided between the economizer, the evaporator and the superheater. The high-pressure turbine includes a control valve. The method for low load operation of a power plant with a once-through boiler and a high pressure turbine includes providing a parameter indicative of the stable operation of the once-through boiler in once-through operation, and on the basis of this parameter adjusting the control valve in order to regulate the pressure within the economizer and evaporator and/or adjusting the temperature of the water supplied to the economizer.

The invention relates generally to methods and apparatus for start-up and control of liquid salt energy storage combined cycle systems.

An exhaust gas latent-heat recovery device includes: a heat transfer tube disposed inside a duct through which exhaust gas flows, the heat transfer tube having a water supply inlet into which water to be heated for recovering latent heat of the exhaust gas is supplied and a water supply outlet through which the water to be heated is discharged; and a water supply control part configured to control supply of the water to be heated to the water supply inlet. The water supply control part is configured to control supply of the water to be heated from the water supply inlet so that an outlet temperature being a temperature of the water to be heated at the water supply outlet is at a set temperature.

Systems and methods for controlling a heat engine system are provided. One method includes initiating flow of a working fluid through a working fluid circuit having a high pressure side and a low pressure side by controlling a pump to pressurize and circulate the working fluid through the working fluid circuit and determining a configuration of the working fluid circuit by determining which of a plurality of waste heat exchangers and which of a plurality of recuperators to position in the high pressure side of the working fluid circuit. The method also includes determining, based on the determined configuration of the working fluid circuit, for each of a plurality of valves, whether to position each respective valve in an opened position, a closed position, or a partially opened position and actuating each of the plurality of valves to the determined opened position, closed position, or partially opened position.

Systems and methods for controlling a heat engine system are provided. One method includes initiating flow of a working fluid through a working fluid circuit having a high pressure side and a low pressure side by controlling a pump to pressurize and circulate the working fluid through the working fluid circuit and determining a configuration of the working fluid circuit by determining which of a plurality of waste heat exchangers and which of a plurality of recuperators to position in the high pressure side of the working fluid circuit. The method also includes determining, based on the determined configuration of the working fluid circuit, for each of a plurality of valves, whether to position each respective valve in an opened position, a closed position, or a partially opened position and actuating each of the plurality of valves to the determined opened position, closed position, or partially opened position.