GB1300948A - Improvements in or relating to power plants - Google Patents

Abstract

1300948 Gas turbine plant; turbine power plant ROLLS ROYCE Ltd 22 Oct 1970 [7 Oct 1969] 49234/69 Headings F1G and F1Q A power plant comprises a fluidized bed combustion apparatus connected to receive and heat a working fluid in heat exchange relation with the fluidized bed, turbine means connected to receive and be driven by the working fluid so heated, compressor means connected to supply air under pressure to the fluidized bed combustion means to support combustion therein, and auxiliary combustion means to heat the compressed air prior to its entry into the fluidized bed combustion means. The embodiment shown is a closed cycle gas turbine plant the working fluid of which is helium. The working fluid is compressed in two compressors 10, 12 in series flow with interstage cooling 26, the working fluid then being preheated in coil 30 of heat exchanger 28, further pre-heated in coil 48 of heat exchanger 46 and then heated in coil 39 disposed in the fluidized bed combustion apparatus 34. The heated working fluid then passes to turbine 16 which drives the compressors 10, 12 through shaft 18, and turbine 20 which is a separate power turbine driving electric generator 22. The exhaust gas from turbine 20 passes through coil 32 of heat exchanger 28 to pre-heat working fluid in coil 30, the exhaust gas then being pre-cooled in cooler 24 before passing to the inlet of compressor 10. Air under pressure is supplied by a compressor 38 to inlet 37 of the fluidized bed combustion chamber 34, the air serving to support combustion of the granulated fuel forming the bed, the air from the compressor being controlled by valve 56 and being heated in coil 54 of heat exchanger 50 before passing to an auxiliary combustion chamber 58 to which fuel is supplied, the combustion gases passing to the fluidized bed combustion chamber 34. The gases discharge from the combustion chamber to a turbine 40 which is connected to drive the compressor 38 also an electric generator 42, the exhaust gases from the turbine being divided, one flow passing through coil 52 of heat exchanger 50 to heat the air under pressure in coil 54, and the second flow passing through coil 44 of heat exchanger 46 to pre-heat working fluid in coil 48. A combustion chamber 62 is disposed in the line from the fluidized bed combustion chamber 34 to the turbine 40. Air from the compressor 38 may pass to the inlet of the combustion chamber 62 or to a mixing device 64 in dependence on opening of valves 70 and 68. In place of a closed cycle gas turbine plant, as shown, a steam turbine plant may be used, the coil 39 serving as a steam generator and the exhaust steam from the turbine passing to a condenser and feed pump. The combustion chambers 58 and 62 are only used at starting although the combustion chamber 62 may be utilized when the main turbine set is closed down, the compressor 38, combustion equipment 62 and turbine 40 constituting a gas turbine engine driving the generator 42.