GB1300016A - Gas/steam turbine plant - Google Patents

Abstract

1300016 Combined steam and gas turbine plant SULZER BROS Ltd 28 July 1971 [12 Aug 1970] 35410/71 Headings F1G and F1Q The invention relates to a combined gas and steam turbine plant in which steam discharged from an HP turbine is divided into two parts, one part being mixed with combustion gases passing to a gas turbine, the second part being reheated and then supplied to an LP steam turbine. The plant shown comprises a combustion chamber 8 defined by a wall 9 which comprises a series of vapourising tubes welded together and by a lower end wall 10 through which a fuel and air burner 7 projects, the combustion chamber being enclosed within a sheet metal jacket 13, the assembly being disposed within a pressure vessel 12 having an exhaust gas outlet 20. Feed water is supplied from the feed water tank 50, steam passing from the header 53 to the super-heater section 11 from which it passes through line 54. The plant comprises also an air compressor 1, a gas turbine 21, an HP steam turbine 56, an LP steam turbine 66 and an electric generator 22 all disposed on a common shaft 23. Air from the compressor discharges through line 2 to a distributor 3 from which part passes through line 6 to the burner 7. Combustion gases discharge from the chamber 8 through the space between the chamber and the jacket 13, through the discharge duct 20 to the gas turbine 21. The exhaust gases discharge from the turbine through a heat exchanger 31 in which are disposed an interstage steam reheat coil 32 and a feed water heater coil 33. A portion of air passes from the distributor under control of valve 41 together with part of the steam discharged from HP steam turbine 56 through line 60 to the distributor 3, into the space between the combustion chamber jacket 13 and the pressure vessel 12 for cooling purposes finally mixing with the combustion gases discharging from the chamber 8. Steam from the super-heater 11 passes through line 54 to the HP steam turbine 56 from which part passes through line 60 to the distributor 3 and the remainder passes through line 61 to the interstage reheat coil 32. The reheated steam passes through line 65 to the LP steam turbine 66 from which the steam discharges to a condenser 67, feed water heater 69 (heated by steam bled from the LP turbine), feed water heater 33, de-aerator 76 to feed water tank 50. A valve 62 in steam line 61 is controlled in dependence on temperature of the gases entering the gas turbine as sensed at 82.