There is provided a drain recovery system with which power for driving a feedwater pump can be reduced and the feedwater pump can be driven at low costs. The drain recovery system includes: a buffer tank; an assist tank disposed below the buffer tank; a first drain supply line that connects a load device and the buffer tank; a second drain supply line that connects the buffer tank and the assist tank; a drain supply valve; a communication line that establishes communication between the assist tank and the buffer tank; a communication valve; a steam supply line that supplies steam from a boiler to the assist tank; a steam supply valve; a feedwater line that supplies drain from the assist tank to the boiler; and a feedwater pump.

A method for operating a forced-flow steam generator constructed as a waste-heat steam generator having a pre-heater, including pre-heater heating surfaces, and having an evaporator including evaporator heating surfaces connected downstream on the flow medium side of the pre-heater heating surfaces. A device for adjusting a feed water mass flow has a set point for the feed water mass flow. During the creation of the set point for the feed water mass flow, a waste-heat flow transferred to a fluid in the evaporator heating surfaces is determined, and mass storage and energy storage in the fluid in the evaporator heating surfaces is detected during non-steady-state plant operation. A behaviour over time of a mass storage in the evaporator is coupled with a behaviour over time of a mass storage in the pre-heater, wherein scaling is carried out with a ratio of the density changes in the evaporator and pre-heater

A method for operating a forced-flow steam generator constructed as a waste-heat steam generator having a pre-heater, including pre-heater heating surfaces, and having an evaporator including evaporator heating surfaces connected downstream on the flow medium side of the pre-heater heating surfaces. A device for adjusting a feed water mass flow has a set point for the feed water mass flow. During the creation of the set point for the feed water mass flow, a waste-heat flow transferred to a fluid in the evaporator heating surfaces is determined, and mass storage and energy storage in the fluid in the evaporator heating surfaces is detected during non-steady-state plant operation. A behaviour over time of a mass storage in the evaporator is coupled with a behaviour over time of a mass storage in the pre-heater, wherein scaling is carried out with a ratio of the density changes in the evaporator and pre-heater

A method includes determining, via a processor, a commanded fluid flow rate of a fluid entering or exiting the drum of an industrial system, wherein the commanded fluid flow rate comprises a rate of fluid entering the drum of the industrial system, exiting the drum of the industrial system, or a combination thereof. The method additionally includes determining, via the processor, a measured flow rate of the fluid. The method further includes determining, via the processor, a variable multiplier based at least in part on the commanded fluid flow rate and the measured flow rate; and deriving, via the processor, a multiplied flow rate command for the industrial system by applying the variable multiplier to the commanded fluid flow rate.

A method includes determining, via a processor, a commanded fluid flow rate of a fluid entering or exiting the drum of an industrial system, wherein the commanded fluid flow rate comprises a rate of fluid entering the drum of the industrial system, exiting the drum of the industrial system, or a combination thereof. The method additionally includes determining, via the processor, a measured flow rate of the fluid. The method further includes determining, via the processor, a variable multiplier based at least in part on the commanded fluid flow rate and the measured flow rate; and deriving, via the processor, a multiplied flow rate command for the industrial system by applying the variable multiplier to the commanded fluid flow rate.

A method of suppressing steam production in a HRSG where a volume of feed water is diverted upstream bypassing a portion of the economizer and returning the volume of diverted feed water to a downstream portion of the economizer. A control logic circuit is used to manipulate a suppression control valve regulating the bypassed feed water, thereby reducing the temperature of water in the steam drum. Bypassing feed water flow into a downstream portion of an economizer reduces the steam production rate in the steam drum by increasing the evaporator approach temperature, permitting gas turbines to operate at base load even after an upgrade, by preventing the waste heat boiler from exceeding its rated capacity and pressure.

A method of suppressing steam production in a HRSG where a volume of feed water is diverted upstream bypassing a portion of the economizer and returning the volume of diverted feed water to a downstream portion of the economizer. A control logic circuit is used to manipulate a suppression control valve regulating the bypassed feed water, thereby reducing the temperature of water in the steam drum. Bypassing feed water flow into a downstream portion of an economizer reduces the steam production rate in the steam drum by increasing the evaporator approach temperature, permitting gas turbines to operate at base load even after an upgrade, by preventing the waste heat boiler from exceeding its rated capacity and pressure.

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.

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.

Provided are a method and system for improving control of a steam generator level for preventing oscillation of the steam generator level in a nuclear power plant. In order to prevent oscillation of a steam generator level and resultant shutdown of a nuclear reactor, which may be caused when a high-level priority control function is frequently and repeatedly turned on/off as the steam generator level is excessively increased, by improving a feedwater control system in the nuclear power plant, a proportional integral control value may be controlled to be reduced, and thus, output while a certain condition is met after a high-level priority mode is deactivated or a signal instructing to enter the high-level priority control mode may be controlled not to be output.