Abstract: A feedwater heater (10) for a steam generator communicating feedwater through an external heat exchanger (12), a deaerator (14) that allows the use of carbon steel feedwater tubes, a first heater (16), an evaporator section (18) and steam drum (17) for communicating a portion of the feedwater in the form of steam to the deaerator (14), and a second heater (20).

Abstract: A heat recovery steam generator includes a casing for receiving exhaust gas from a turbine, a heat exchanger positioned within the casing for thermal communication with the exhaust gas, and an ammonia vapor distributor positioned within the casing. An ammonia vaporization unit is configured for conversion of aqueous ammonia to ammonia vapor and communication of the ammonia vapor to the distributor. A first extraction line operatively connects between the casing and the ammonia vaporization unit for communication of exhaust gas to the ammonia vaporization unit. A second extraction operatively connects between the casing and the ammonia vaporization unit for communication of exhaust gas to the ammonia vaporization unit. A catalytic reduction system is located within the casing and positioned downstream from the distributor for effecting a reaction between the ammonia vapor and NOx in the exhaust gas.

Abstract: A heat recovery steam generator includes a casing for receiving exhaust gas from a turbine, a heat exchanger positioned within the casing for thermal communication with the exhaust gas, and an ammonia vapor distributor positioned within the casing. An ammonia vaporization unit is configured for conversion of aqueous ammonia to ammonia vapor and communication of the ammonia vapor to the distributor. A first extraction line operatively connects between the casing and the ammonia vaporization unit for communication of exhaust gas to the ammonia vaporization unit. A second extraction operatively connects between the casing and the ammonia vaporization unit for communication of exhaust gas to the ammonia vaporization unit. A catalytic reduction system is located within the casing and positioned downstream from the distributor for effecting a reaction between the ammonia vapor and NOx in the exhaust gas.

Abstract: A heat recovery steam generator (HRSG) (A) has a casing (2) and several heat exchangers in the casing. Some of those heat exchangers (12,16) take the form of coils (18) having multiple lower headers (36) into which the lower ends of tubes (18) open. The tubes (18) and headers (36) hold or may hold water and need to be drained from time to time. To this end, the heat ex changer (12,16) has a drain system (20) provided with drain pipes (40) that are connected to the lower headers (36) and contain check valves (48) that permit the water to flow away from the headers (36), but not into them. The drain pipes (40) lead to and open into a drain manifold (46). The drain pipes (40), check valves (48) and drain manifold (46) are assembled in a shop along with the coil (18) and, when the HRSG (A) is assembled in the field, lie within the interior of the casing (2).

Abstract: A blowoff tank (B) for receiving blowdown, blowoff, and drain water from an HRSG (C) or other type of boiler, so as to lower the temperature of that water enough to enable it to be discharged into a sewer system, includes a generally cylindrical vessel (50) and inlet pipes (60) through which the blowdown, blowoff, and drain water is introduced into the vessel. Each pipe has a radial segment (62) that passes through the sidewall (52) of the vessel, a generally vertical segment (64) that extends upwardly within the vessel, and a tangential segment (68) that opens into the vessel. The radial segment contains a small drain aperture (74). The tank also has a cooling line (90) through which cooling water is introduced into the vessel to lower the temperature of the blowdown, blowoff, and drain water in the vessel and a drain line (86) that drains the mixture of cooling water and blowdown, blowoff, and drain water from the vessel, but never exceeds the elevation of the apertures in the inlet pipes.

Abstract: A feedwater heater (10) for a steam generator communicating feedwater through an external heat exchanger (12), a deaerator (14) that allows the use of carbon steel feedwater tubes, a first heater (16), an evaporator section (18) and steam drum (17) for communicating a portion of the feedwater in the form of steam to the deaerator (14), and a second heater (20).

Abstract: A blowoff tank (B) for receiving blow-down, blowoff, and drain water from an HRSG (C) or other type of boiler, so as to lower the temperature of that water enough to enable it to be discharged into a sewer system, includes a generally cylindrical vessel (50) and inlet pipes (60) through which the blowdown, blowoff, and drain water is introduced into the vessel. Each pipe has a radial segment (62) that passes through the sidewall (52) of the vessel, a generally vertical segment (64) that extends upwardly within the vessel, and a tangential segment (68) that opens into the vessel. The radial segment contains a small drain aperture (74). The tank also has a cooling line (90) through which cooling water is introduced into the vessel to lower the temperature of the blowdown, blowoff, and drain water in the vessel and a drain line (86) that drains the mixture of cooling water and blowdown, blowoff, and drain water from the vessel, but never exceeds the elevation of the apertures in the inlet pipes.

Abstract: A feedwater heater for an HRSG is provided with a monitoring unit for detecting the presence of condensation in the feedwater heater. The monitoring unit includes a dielectric band around one of the tubes of the feedwater heater near the location where the feedwater is directed into the heater and a conductive band located around the dielectric band. The unit also includes a conductivity sensor installed between a ground on the feedwater heater and the conductive element. Hot gases containing moisture pass through the feedwater heater, and if the temperature of surfaces in the region of the tube around which the dielectric and conductive bands extend drops below the dew point of the gas, an electrically conductive condensate will appear those surfaces and on the tube and will flow over the dielectric band, completing an electric circuit between the tube and the conductive band. The conductivity sensor detects this and hence detects the presence of the condensation.

Abstract: A steam generator has a once-through evaporator which converts liquid water into steam in tubes over which hot gases flow. Each tube contains a metal tape which is twisted into a helical configuration to induce turbulence in the mist produced by the boiling, and the turbulence insures that the mist wets the inside surfaces of the tubes, thus producing good heat transfer and moderate temperatures in the tubes.

Abstract: An evaporator in a steam generator extracts heat from high temperature gases to convert heated water into saturated steam. The evaporator includes two sections—a once-through section and a circulation section, both of which include tubes located in the flow of hot gases. Heated water flows through the tubes of the once-through section at a rate sufficient to maintain the interiors of its tube fully wetted while enabling steam to develop in that water, with the steam having a quality of at least 20%. The circulation section includes a drum that is connected to the tubes of that section such that water from the drum circulates through the tubes and then back to the drum, with the circulation being such that the water in the tubes of the circulation section keeps the tubes fully wetted while steam develops in that water. The water from the tubes of the once-through section discharges into the drum as does the water circulating back from the tubes of the circulation section.