Combustion Engineering, Inc.

Thomas P Mastronarde

Raymond L Beauregard

A combined cycle system has a gas turbine for generating an exhaust gas stream and a heat recovery steam generator with a housing for defining a horizontal exhaust gas flow path for the exhaust gas stream. Positioned within the housing is a heat recovery assembly having vertical rows of horizontally oriented heat transfer tubes transverse to the direction of gas flow and spaced apart in the direction of the gas flow path. The heat transfer tubes are supported by a plurality of vertical support plate assemblies oriented parallel to the exhaust flow path. Each support plate assembly has a plurality of coplanar support plate segments, each support plate segment supporting less than three rows of heat transfer tubes.

Heat recovery assembly

A heat recovery generator has a housing defining a horizontally oriented exhaust gas stream. The exhaust gas stream passes through a first heat recovery unit having horizontally oriented heat transfer tubes and forced circulation of a heat transfer fluid therethrough. The exhaust gas stream then is passed through an air pollution control assembly having a catalyst for reduction of exhaust emissions. The exhaust gas stream is subsequently passed through a second heat recovery steam generator having vertically oriented heat transfer tubes and natural circulation therethrough.

Gas turbine heat recovery steam generator and method of operation

A waste heat boiler (10, 38) of the type which is particularly suited for use in marine applications and which incorporates a feed mixing nozzle (50) that is operative for purposes of effecting, by utilizing steam taken from the steam generating bank (20, 48), a preheating of the feedwater that is fed to the steam drum (14, 42). In addition to the aforesaid feed mixing nozzle (50), the subject waste heat boiler (10, 38) includes a feedwater control valve (12, 40), a steam drum (14, 42), a circulation pump (18, 46), a steam generating bank (20, 48) and a centrifugal water separator (16, 44). The feedwater control valve (12, 40) is employed to modulate the flow rate of the incoming feedwater in order to maintain the desired level of water in the steam drum (14, 42). In turn the latter steam drum (14, 42) is intended to function in the manner of a reservoir for the circulating water that through the operation of the circulating pump (18, 46) is supplied to the steam generating bank (20, 48). The circulating water which is supplied to the steam generating bank (20, 48) is heated therein to saturation temperature, and steam is generated thus. A water-steam mixture is returned from the steam generating bank (20, 48) to the steam drum (14, 42) and is directed into the centrifugal water separator (16, 44) that is suitably located within the steam drum (14, 42). It is in the centrifugal water separator (16, 44) that the separation of the water-steam mixture is effected such that water is returned to the lower portion of the steam drum (14, 42) and the steam is supplied to the upper portion of the steam drum (14, 42). The preheating of the feedwater is accomplished by directing the incoming feedwater through an internal feed pipe (66) to the mixing nozzle (50), the latter being positioned in the line (60) through which the water-steam mixture is returned to the steam drum (14, 42).

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South Windsor, CT, United States of America

Thomas P Mastronarde