Abstract: A method for operating a combined cycle power plant includes transferring exhaust gas from a gas turbine to a heat recovery steam generator. Further, the method includes preheating condensate before being fed as feedwater to the heat recovery steam generator. Moreover, the method includes reheating the feedwater in the heat recovery steam generator. The method also includes generating steam in the heat recovery steam generator for a steam turbine, wherein preheating the condensate includes monitoring a temperature of the condensate: if the temperature of the condensate is equal to or above a preset temperature, directing the condensate to a low-pressure economizer of the heat recovery steam generator; if the temperature of the condensate is lower than the preset temperature: directing a first fluid from an intermediate source of the low-pressure economizer to heat the condensate.

Abstract: A water/steam system for a combined cycle power plant and related method for operating said system are provided. The system comprises a heat recovery steam generator providing a flue gas stream path for extracting heat from a flue gas stream exhausted from a gas turbine, the heat recovery steam generator having a low pressure section including a low pressure evaporator arranged along the flue gas stream path for generating low pressure steam at a low pressure input level for a main input of a low pressure steam turbine. To use heat at low temperatures, the low pressure section may include a sub low pressure subsection with a sub low pressure evaporator for generating sub low pressure steam, at a sub low pressure level below the low pressure input level. The sub low pressure evaporator is disposed in the flue gas stream path downstream of a low pressure economizer.

Abstract: A method for operating a combined cycle power plant includes transferring exhaust gas from a gas turbine to a heat recovery steam generator. Further, the method includes preheating condensate before being fed as feedwater to the heat recovery steam generator. Moreover, the method includes reheating the feedwater in the heat recovery steam generator. The method also includes generating steam in the heat recovery steam generator for a steam turbine, wherein preheating the condensate includes monitoring a temperature of the condensate: if the temperature of the condensate is equal to or above a preset temperature, directing the condensate to a low-pressure economizer of the heat recovery steam generator; if the temperature of the condensate is lower than the preset temperature: directing a first fluid from an intermediate source of the low-pressure economizer to heat the condensate.

Abstract: A power plant (1) that includes at least one of a gas turbine (GT), a steam turbine (ST) with a water-steam cycle, and a heat recovery steam generator (B) operatively connected to a heat generating member such as solar energy system (Ssolar) by means of a primary circuit (10a, 10b, 10c) and a secondary circuit system (20a). The primary heat transfer circuit (10a, 10b) includes solar heating system (Ssolar) configured to heat a primary fluid (10), and the secondary circuit (20a) comprises a flow line (20A) for a secondary flow (20) and a main heat exchanger (23) to exchange heat between the secondary water flow and a gas turbine inlet air flow (2). A first line (10B) in the primary circuit (10b) leads to a first heat exchanger (12) to heat the water flow in the secondary circuit (20a).

Abstract: A power plant system including a fossil fuel fired power plant (6) for the generation of electricity, a carbon dioxide capture and compression system (5, 13), and an external heat cycle system has at least one heat exchanger (1,2,3) for the heating of the flow medium of the external heat cycle system. The heat exchanger (1,2,3) is connected to a heat flow from the CO2 capture plant (5) or a CO2 compression unit (13). A return flow from the heat exchanger (1,2,3) is led to the CO2 capture and compression system (5,13) or to the power plant (6). The power plant system allows an increase in overall efficiency of the system.

Abstract: A water/steam system for a combined cycle power plant and related method for operating said system are provided. The system comprises a heat recovery steam generator providing a flue gas stream path for extracting heat from a flue gas stream exhausted from a gas turbine, the heat recovery steam generator having a low pressure section including a low pressure evaporator arranged along the flue gas stream path for generating low pressure steam at a low pressure input level for a main input of a low pressure steam turbine. To use heat a low temperatures, embodiments of the system provide that in the low pressure section, additional sub low pressure steam, at a sub low pressure level below the low pressure level, is generated by a sub low pressure evaporator in the flue gas stream path.

Abstract: The feedwater preheating system includes a feedwater tank and a constant volume recirculation pump. The feedwater tank is adapted to store the feedwater. The feedwater tank includes feed and return lines. The feed line is adapted to feed the feedwater to the HRSG, and the return line enables returning of the feedwater into the feedwater tank. The return line precludes a control valve, and is configured to the feedwater tank to reduce component loss while feedwater recirculation. The constant volume recirculation pump is configured in the feed line to recirculate the feedwater between the HRSG and the feedwater tank. The pump is capable of recirculating the feedwater at constant speed and volume to reduce heat loss while feedwater recirculation, as against the prior art feedwater preheating systems.

Abstract: The invention relates to a combined cycle power plant that includes, a gas turbine plant, a heat recovery steam generator heated by hot waste gases of a gas turbine plant, and a steam turbine plant driven by the steam produced, and a waste gas purification plant, arranged downstream of the heat recovery steam generator in which carbon oxides in the waste gases can be absorbed by an absorber fluid, which is subsequently regenerated at an elevated temperature in a regenerating section while giving up the carbon oxides for supplying to a storage. The regenerating section has a heater for maintaining a necessary elevated temperature for regeneration. The heater operates with steam from the heat recovery steam generator or from the steam turbine plant. The steam condenses and the resulting hot condensate can be supplied to a flash boiler where it, at low pressure, immediately at least partially evaporates.

Abstract: A power plant (1) that includes at least one of a gas turbine (GT), a steam turbine (ST) with a water-steam cycle, and a heat recovery steam generator (B) operatively connected to a heat generating member such as solar energy system (Ssolar) by means of a primary circuit (10a, 10b, 10c) and a secondary circuit system (20a). The primary heat transfer circuit (10a, 10b) includes solar heating system (Ssolar) configured to heat a primary fluid (10), and the secondary circuit (20a) comprises a flow line (20A) for a secondary flow (20) and a main heat exchanger (23) to exchange heat between the secondary water flow and a gas turbine inlet air flow (2). A first line (10B) in the primary circuit (10b) leads to a first heat exchanger (12) to heat the water flow in the secondary circuit (20a).

Abstract: A power plant system including a fossil fuel fired power plant (6) for the generation of electricity, a carbon dioxide capture and compression system (5, 13), and an external heat cycle system has at least one heat exchanger (1,2,3) for the heating of the flow medium of the external heat cycle system. The heat exchanger (1,2,3) is connected to a heat flow from the CO2 capture plant (5) or a CO2 compression unit (13). A return flow from the heat exchanger (1,2,3) is led to the CO2 capture and compression system (5,13) or to the power plant (6). The power plant system allows an increase in overall efficiency of the system.