GB889221A - Improvements in or relating to binery elastic fluid power plants - Google Patents

Abstract

889,221. Forced-flow steam boilers. BABCOCK & WILCOX CO. Nov. 14, 1958 [Nov. 15, 1957], No. 36771/58. Classes 123(2) and 123(3) In a once-through forced flow steam generator 13 the outlet headers of water tubes, defining the walls 19-22 of an upright furnace chamber 18 which is located in a cylindrical metal vessel 13 to form an annular air space 23, are connected by tubes 93 to a primary superheater 36 which is accommodated in a gas recirculation pass 38, 34 and is connected by tubes 94 to a secondary superheater 26 arranged centrally of the chamber 18. Pipes 97 connect the secondary superheater 26 to a final superheater 32 which is housed in one pass 28 of two parallel passes 27, 28 formed, in the upper part B fo the chamber 18, by an upright metal baffle extending between the side walls 21, 22 of the chamber 18. The superheater 32 is connected by a duct 98 to the high pressure stage of a turbine 14 which drives an electric generator 15. Expanded steam from the turbine passes through a conduit 101 to a reheater 31 which is arranged in the pass 27 and delivers steam through a pipe 102 to a low pressure stage of the turbine 14. The upper ends of the front and rear wall tubes 19, 20 are return bent to form gas passes 19A, 20A respectively the wall tubes being bent inwardly at 83, 85 and 84, 86 to form gas inlet and outlet pasasges. The flow of gas through the passes 27, 28 and the by-passes 19A, 20A is controlled by dampers 99, 95, and 124, 125 respectively. A gas turbine 11 is connected by a pipe 40 to the upper end of the chamber 18 the apportioning of gas flow between the duct 40 and the gas recirculation duct 38 being regulated by dampers 126 located in the pipe 40. Gas exhausted by the turbine 11 passes successively through an air heater 12 and an economiser 116 through which previously heated feed water passes to a pipe 66 connected to tubes which define the cylindrical and frusto-conical end parts 58 of the combustion chambers 49 of a pair of independently operable solid fuel cyclone furnaces 24, 25. The latter are arranged in casings in the vessel 13 opposite throats 64 in the front and rear walls 19, 20 of the lower portion A of the chamber 18. The molten slag from the furnaces 24, 25 flows through outlets 65 into the furnace chamber portion A and discharges through an outlet 81 into a slag tank 82. The tubes of each combustion chamber 49 are arranged to form tangential inlets 57 for the introduction of secondary combustion air from the air space 23. The gas turbine drives an electric generator 16 and a compressor 10 which forces combustion air through the air heater 12 to an annular space 35 between the gas pass 34 and an upright vessel 33 which surrounds and supports it. The air space 35 communicates with the space 23 through a space 39 between the recirculation gas duct 38 and a metal conduit 37 which interconnects the upper ends of the vessels 17, 33. A fan 42 withdraws combustion gases from the lower end of the pass 38 and recirculates it through a pipe 45 leading to the lower end A of the chamber 18. A damper controlled by pass 118 extends from the air pipe, leading from the air heater 116 to the air space 35, to the pipe 45. The chamber 18 is top supported from a cap member 103 of the vessel 13 which is supported at its base by upright members 108. In another generally similar arrangement the chamber 18 is extended upwardly to accommodate the primary superheater 36 and the upright vessel 17 is extended upwardly beyond the chamber 18 to accommodate the fan 42. Baffling is arranged in the space 23 so that air entering the space from a pipe leading from the fan 42 passes upwardly along part of the space 23 and downwardly along the other part to the furnaces 24, 25. A central by-pass, located between the passes 19A, 20A, replaces the by-passes 19A, 20A.