GB682141A - Improvements in combined steam turbine and gas turbine plants - Google Patents

Abstract

682,141. Gas turbine plant. MASCHINENFABRIK OERLIKON. April 4, 1951 [April.24, 1950], No. 7856/51. Class 110(iii) In a combined multi-stage steam turbine and multi-staged gas turbine plant, at least a part of the gases from the high pressure stage of the gas turbine are used to effect a superheating of the, steam between the stages of the steam turbine plant and at least a part of the exhaust gases of the gas turbine plant gives up heat to the combustion air for the boiler of the steam turbine plant. In the plant shown, steam from a boiler plant I is used in a multi-stage steam turbine plant 11 comprising high, intermediate and low pressure stages 6, 8, 8<SP>1</SP>, interstage superheaters 7, 7<SP>1</SP>, a condenser 9 and an electric generator 10. The compressed air from a compressor 11 of a gas turbine plant III is heated in a heat exchanger 15, further heated in a heat exchanger 4<SP>1</SP> located in the path of the combustion gases leaving the boiler, and then used in a high pressure air turbine 12". The exhaust gases from the turbine 12<SP>11</SP> is used to heat the interstage superheaters 7, 7<SP>1</SP> and the heat exchanger 15 before passing to a combustion chamber 13<SP>1</SP> the gases from which are used to drive a low pressure gas turbine 12<SP>1</SP>. The exhaust gases from the turbine 12<SP>1</SP> are used in part as combustion air in the grate 1 of the boiler and in part to heat the feed water heater 16. In a modification, the air from the compressor 11 is heated in a combustion chamber, which supplies gas to a high pressure turbine the exhaust of which is used in part in an interstage superheater and in part in a feed water heater. After passing through the superheater and feed water heater, the gases are re-united and then pass to another combustion chamber which supplies a low pressure turbine. It is stated that part of exhaust gases of the high or low pressure turbines may be used to heat the compressed air leaving the compressor. When multiple interstage superheating is employed the temperature of the superheated steam in the various superheaters may be different from one another. The compressor may be arranged in two stages driven by the high pressure and low pressure turbines respectively or the compressor may be driven by the low pressure turbine at variable speed independently of the high pressure turbine. The combustion chamber before the low pressure turbine may be dispensed with.