A once-through steam generator comprises a duct having an inlet end in communication with a source of a hot gas; and a tube bundle installed in the duct and comprising multiple heat transfer tubes. The tube bundle has an economizer section, an evaporator section, and a superheater section. A steam separating device may be positioned between the evaporator section and the superheater section, wherein, as part of a wet start-up, hot water collected by the steam separating device is delivered from the steam separating device to mix with cold feedwater before it is introduced into the economizer section. A start-up module may be positioned in the duct near the inlet end, wherein, as part of a dry start-up, cold feedwater is delivered into the start-up module to generate hot water that is then mixed into the feedwater stream before it is introduced into the economizer section.

A once-through steam generator comprises a duct having an inlet end in communication with a source of a hot gas; and a tube bundle installed in the duct and comprising multiple heat transfer tubes. The tube bundle has an economizer section, an evaporator section, and a superheater section. A steam separating device may be positioned between the evaporator section and the superheater section, wherein, as part of a wet start-up, hot water collected by the steam separating device is delivered from the steam separating device to mix with cold feedwater before it is introduced into the economizer section. A start-up module may be positioned in the duct near the inlet end, wherein, as part of a dry start-up, cold feedwater is delivered into the start-up module to generate hot water that is then mixed into the feedwater stream before it is introduced into the economizer section.

An electrolyzer system includes a steam generator configured to generate steam, a stack of solid oxide electrolyzer cells configured to generate a hydrogen stream using the steam received from the steam generator, and a water preheater configured to preheat water provided to the steam generator using heat extracted from oxygen exhaust output from the stack.

An electrolyzer system includes a steam generator configured to generate steam, a stack of solid oxide electrolyzer cells configured to generate a hydrogen stream using the steam received from the steam generator, and a water preheater configured to preheat water provided to the steam generator using heat extracted from oxygen exhaust output from the stack.

Methods and systems for controlling the temperature of a heated flue gas stream downstream of a multi-part heat exchanger within a desired operating range through the use of a fluid bypass line which bypasses one or more sections, but not all sections, of the multi-part heat exchanger. In some but not necessarily all embodiments some fluid flow is maintained through the heat exchanger at all times. In one embodiment, the method includes sensing a temperature in said flue gas stream in proximity to an intermediate header of said multi-part heat exchanger and controlling a position of a bypass line control valve to control an amount of fluid passing through a fluid bypass line that bypasses the section of the multi-part heat exchanger between an inlet header and the intermediate header based on said temperature in said flue gas stream in proximity to the intermediate header of said multi-part heat exchanger.

Methods and systems for controlling the temperature of a heated flue gas stream downstream of a multi-part heat exchanger within a desired operating range through the use of a fluid bypass line which bypasses one or more sections, but not all sections, of the multi-part heat exchanger. In some but not necessarily all embodiments some fluid flow is maintained through the heat exchanger at all times. In one embodiment, the method includes sensing a temperature in said flue gas stream in proximity to an intermediate header of said multi-part heat exchanger and controlling a position of a bypass line control valve to control an amount of fluid passing through a fluid bypass line that bypasses the section of the multi-part heat exchanger between an inlet header and the intermediate header based on said temperature in said flue gas stream in proximity to the intermediate header of said multi-part heat exchanger.

A preheating system for preheating fluid medium to be fed into the HRSG is disclosed. The system includes a feed line and a recirculation line. The feed line is adapted to feed the fluid medium to a Low Pressure Economizer (LPE) of the HRSG. The feed line is adapted to be adjoined to an inlet of the LPE, and an outlet of the LPE enables therefrom the flow of the fluid medium in further portion of the HRSG. The recirculation line is adapted to be connected between the outlet and the inlet of the LPE, in parallel to LPE to recirculate the fluid medium to the LPE. A particular method of preheating using such a system is equally disclosed.

A heat recovery steam generator (HRSG) (10) including: an economizer (12) configured to heat a working fluid by extracting heat from a flow of flue gas (20). The HRSG includes a diluting fluid injector arrangement (60) configured to inject a diluting fluid (50) effective to dilute a concentration of a gaseous corrosive when compared to an undiluted concentration of the gaseous corrosive in the flow of flue gas. The HRSG also includes a preheater (18) configured to preheat the diluting fluid prior to injection.

A heat recovery steam generator (HRSG) (10) including: an economizer (12) configured to heat a working fluid by extracting heat from a flow of flue gas (20). The HRSG includes a diluting fluid injector arrangement (60) configured to inject a diluting fluid (50) effective to dilute a concentration of a gaseous corrosive when compared to an undiluted concentration of the gaseous corrosive in the flow of flue gas. The HRSG also includes a preheater (18) configured to preheat the diluting fluid prior to injection.