GB1142692A - Supercharged vapor generator - Google Patents

Abstract

1,142,692. Once through steam generators; preheating combustion air; tubular heat exchangers. FOSTER WHEELER CORP. 23 May, 1966 [10 June, 1965], No. 22978/66. Headings F4A, F4B and F4S. A once through forced flow steam generator comprises an outer circular cross-sectioned containment shell 21 having a first vertical portion 23, a second vertical portion 27 and a connecting horizontal portion 31. A chamber 33 formed from gas-tight finned tubes 35 welded together is located within the shell 21 and comprises a cylindrical section 39 with a bell-shaped end 41, a horizontal rectangular section 43 and a second rectangular vertical section 47. The space between the shell 21 and the chamber 33 defines an annular air passageway 53, compressed air from compressor 117 passing through conduit 119 to air inlet ports 55, from whence the air flows along passageway 53 to be preheated. The air is then delivered to oil or gas burners 67 at the bottom of cylindrical section 39 through air exit ports 57, conduits 59 and air re-entry ports 61. The combustion products flow through the inside of chamber 33 to gas exit ports 69, in compartment 51 to pass to a gas turbine 115 which drives the air compressor 117, through a conduit 111 and an auxiliary fuel combustor 113. From the gas turbine 115 the gases exhaust through conduit 123 to a stack 125. Water from an economizer 95 in stack 125, enters the ring-shaped inlet header 97 and flows through the tubes 35 to first enthalpy equalizing mixing headers 99. From headers 99 the fluid flows in a second pass to second enthalpy equalizing mixing headers 101, and from these headers to ring-shaped outlet header 103. The fluid then flows through primary superheater bank 89 from inlet headers 91 to outlet headers 93, and secondary superheater bank 83 from inlet headers 85 to outlet headers 87, all located in section 47, on its way to turbine high pressure stage 108. Partially expanded steam from this stage then is passed back to inlet header 79 of primary platen reheater 73 located in horizontal section 43, and from reheater 73 passes into a shell and tube attemperator 77, wherein its temperature is controlled by heat exchange with a portion of the incoming feedwater. The reheat steam then passes through pendant reheater 75 to outlet header 81 and so to the intermediate and low pressure turbine stages 110, 112 respectively. The turbine condensate is passed by pump 130 from condenser 129 through low pressure feed heaters 131, to a second pump 132 which delivers it through the economizer 95 to the ring-shaped inlet header 97. A portion of the feedwater flow is tapped off through conduit 118 prior to economizer 95 and passed from inlet 141, Fig. 4, through the U-tubes 143 of shell and tube heat exchanger 77, to outlet 147 whence it passes to the ring-shaped inlet header 97 of the steam generator. Reheat steam from platen reheater 73 enters the shell through headers 151, Fig. 4, and is forced by baffles (153, Fig. 5, not shown) to flow over the U-tubes 143 on its way to outlet tubes 155 forming part of pendant reheater bank 75. The volume of feedwater flowing through the tubes 143 is controlled by a valve 124 to maintain the desired final reheat temperature. The shell 21 and chamber 33 are downwardly supported on rods 157 from a structural framework 155.