GB776269A - A gas turbine plant - Google Patents

Abstract

776,269. Gas turbine plant. LICENTIA PATENT-VERWALTUNGS GES. Nov. 6, 1953 [Nov. 8, 1952], No. 30843/53. Class 110 (3). A gas turbine plant with a closed working fluid circuit comprising a main circuit including a centrifugal compressor, a gas heater, a turbine and a cooler connected in series in which the pressure in the low-pressure section of the circuit between the exhaust point and the suction of the compressor is above atmospheric and an auxiliary or loading circuit including a turbine and centrifugal compressor, has the inlet of the auxiliary turbine connected to the low-pressure section of the main circuit so as to expand part of the working fluid to substantially atmospheric pressure and the auxiliary compressor arranged to take in all or part of the exhaust working fluid for the auxiliary turbine as well as additional working fluid and to discharge it into the main circuit on the suction side of the main centrifugal compressor. Working medium, e.g. air, is heated in a heater 4 and then supplied to a gas turbine 1 driving an electric generator 6 and compressor 2. The turbine exhaust passes through a recuperative heat exchanger 3 and a cooler 5 to the inlet of the compressor 2 which discharges through the heat exchanger 3 back to the heater 4. Working fluid is branched off from the exhaust of the turbine 1 and passed through an auxiliary turbine 7, through a cooler 9 and a loading centrifugal compressor 8 back into the main circuit in front of the cooler 5. Make up air is taken from the atmosphere or a reservoir by the compressor 8 which is driven directly by the turbine 7. A motor generator 10 is connected to compressor-turbine unit 7, 8 to supply additional power to the unit or generate useful power. The compressor 8 may be a multi-stage or multi-casing compressor with intermediate cooling and the turbine 7 may be a multi-stage or multi-casing turbine with intermediate reheating. The heated cooling medium from the cooler 9, or from the intermediate coolers of the compressor 8 or its cooled casing may be utilized for heating purposes. The working medium entering the turbine 7 may be heated in a combustion chamber or gas heater or by re-cycling it through a gas heater of the main circuit. The auxiliary compressorturbine unit 7, 8 may be used to start the main turbine plant and to prevent overheating of the heater 4 if the main plant fails. To start the main plant, the auxiliary compressor-turbine unit is started by the motor-generator 10 and air flows from the compressor 8 through the cooler 5, compressor 2, heat exchanger 3, gas heater 4 and turbine 1 to the turbine 7. Arrangements are made to prevent air from the exhaust of the turbine 1 from flowing through the heat exchanger 3. When the pressure in the main circuit reaches 1 atmosphere above atmospheric, the heater 4 is started. When the turbine 1 begins to rotate, the pressure level in the main circuit increases and the air from the turbine exhaust is passed through the heat exchanger 3. This quantity of air is increased until normal operating conditions are attained. The compressor 8 may be driven independently of the gas turbine plant. The compressor-turbine unit 7, 8 may be used to drive the compressor 2. The compressor 8 may also be used to supply combustion air for the heater 4 and cooling air to the motor-generator 10 or to other generators or consumers of cooling or compressed air. The exhaust of the turbine 7 may also be used to supply combustion air to the heater 4. The turbine 7 may also be used to drive exciting machines of the generators, cooling water pumps, exhaust fans or for other auxiliary drives. A part of the exhaust gas of the turbine 7 may be used for heating purposes or passed through a regenerative heat exchanger forming part of the main circuit.