Various embodiments include a system having: at least one computing device configured to perform actions including: measuring at least one of the following parameters: a steam pressure within a steam drum, a load on a GT, a position of a bypass valve bypassing an HRSG, and a steam flow rate through the steam drum; defining a threshold range for each of: a steam pressure within the steam drum, a load on the GT, a position of the bypass valve bypassing the HRSG and a steam flow rate through the steam drum based upon the measured data and a target steam level; and adjusting the steam flow rate through the steam drum in response to at least one of the measured parameters deviating from the corresponding threshold range.

A combined cycle power plant (CCPP) is provided. The CCPP includes a gas turbine that has a compressor section, a combustion section, and a turbine section. The CCPP further includes a heat recovery steam generator (HRSG) that has a first economizer. The HRSG receives a flow of exhaust gas from the turbine section. The HRSG further includes a fuel heating system that has a fuel supply line and a high temperature heat exchanger disposed in thermal communication on the fuel supply line. The fuel supply line is fluidly coupled to the combustion section. The high temperature heat exchanger is fluidly coupled to the first economizer such that the high temperature heat exchanger receives water from the first economizer. The CCPP further includes a feedwater pump that is fluidly coupled to the high temperature heat exchanger.

A combined cycle power plant (CCPP) is provided. The CCPP includes a gas turbine that has a compressor section, a combustion section, and a turbine section. The CCPP further includes a heat recovery steam generator (HRSG) that has a first economizer. The HRSG receives a flow of exhaust gas from the turbine section. The HRSG further includes a fuel heating system that has a fuel supply line and a high temperature heat exchanger disposed in thermal communication on the fuel supply line. The fuel supply line is fluidly coupled to the combustion section. The high temperature heat exchanger is fluidly coupled to the first economizer such that the high temperature heat exchanger receives water from the first economizer. The CCPP further includes a feedwater pump that is fluidly coupled to the high temperature heat exchanger.

The purpose of the present invention is to decrease the loss of energy of flue gas when superheated steam is cooled and prevent heat efficiency from being decreased. A boiler is provided with: economizers (a medium-pressure economizer (13) and a high-pressure secondary economizer (18)) which heat water supplied by water supply pumps (a medium-pressure water supply pump (27) and a high-pressure water supply pump (28)); evaporators (a medium-pressure evaporator (16) and a high-pressure evaporator (21)) which evaporate the water that is heated by the economizers; and cooling devices (a medium-pressure system and a high-pressure system) which mix water, as a coolant, which has passed through the economizers via the water supply pumps with steam.

A combined cycle power plant and method for operating a combined power plant with stack energy control are presented. The combined cycle power plant includes a gas turbine, a heat recovery steam generator including a plurality of heating surfaces, and a steam turbine. The heating surfaces may be partially bypassed to reduce steam production in the heat recovery steam generator during power plant startup. Less energy may be extracted from exhaust gas of the gas turbine. More energy may be dumped through an exhaust stack. The steam turbine may start without restriction of a gas turbine load during power plant startup. The steam turbine may start without increasing a size of an air cooled condenser while maintaining a higher load of a gas turbine during power plant startup.

A method includes determining, via a processor, a commanded temperature rate for a component of a steam turbine system. The method further includes determining, via the processor, a measured temperature rate for the component of the steam turbine system. The method additionally includes determining, via the processor, a variable multiplier based at least in part on the commanded temperature rate and the measured temperature rate. The method also includes deriving, via the processor, a multiplied temperature rate command by applying the variable multiplier to the commanded temperature rate.

A method for adjusting startup floor pressure levels of HRSG steam circuits is implemented by a pressure controlling computing device including a processor and a memory. The method includes receiving a plurality of measured plant operating values associated with a HRSG steam circuit, identifying a plurality of candidate pressure levels for use in pressurizing the HRSG steam circuit, determining a calculated steam velocity level for each of the plurality of candidate pressure levels, identifying a steam velocity limit for a steam piping section of the HRSG steam circuit, selecting a lowest pressure level of the plurality of candidate pressure levels, wherein the lowest pressure level is associated with a determined calculated steam velocity level that does not exceed the identified velocity limit, and pressurizing the HRSG steam circuit to the selected lowest pressure level.

The purpose of the present invention is to maintain the intake pressure of a water supply pump at an operable pressure. A boiler is provided with: condensate pumps (a condensate pump and an auxiliary condensate pump); a branch line that causes water delivered by the condensate pumps to branch; a drum (a low-pressure drum) that is connected to one (a low-pressure branch line) of two lines into which the branch line branches; and a water supply pump that is connected to the other (a high-pressure branch line) of the two lines into which the branching line branches and that pumps water to an evaporator (a high-pressure evaporator). The boiler is additionally provided with pressure applying means that guides a portion of the water in the drum to the water supply pump side when the intake pressure on the inlet side of the water supply pump has become lower than a predetermined pressure.

An exhaust heat recovery system may a condenser having a working fluid introduced thereinto and recovering heat of the introduced working fluid, the introduced working fluid receiving heat of exhaust gas through a heat exchanger provided in an exhaust pipe, and a reservoir receiving the working fluid from the condenser, wherein the condenser and the reservoir are provided with a coolant channel through which a coolant for cooling the working fluid flows.

A power generation system including a gas turbine is disclosed. The power generation system includes a steam supply system including a high-temperature high pressure superheater and a high-temperature intermediate pressure reheater; a steam turbine assembly including at least one of a non-condensing steam turbine, a high-pressure steam turbine section, an intermediate-pressure steam turbine section; and a low-pressure steam turbine section, and, a control system coupled to the steam supply system and to the steam turbine assembly. The control system configured to selectively control a supply of reheat steam to the non-condensing steam turbine and to the intermediate-pressure steam turbine section; and selectively control a supply of high pressure superheated steam to the non-condensing steam turbine and high-pressure steam turbine section.