GB701515A - Improvements in or relating to gas turbine cycles - Google Patents

Abstract

701,515. Gas turbine plant. POWER JETS (RESEARCH & DEVELOPMENT), Ltd. Sept. 12, 1951 [Sept. 14, 1950], No. 22672/50. Class 110 (3) A gas turbine plant for utilizing a solid water bearing fuel such as bagasse, sewage sludge, coal slurry, sulphite pulp mill waste, town refuse or peat, comprises a source of compressed air which has been heated by compression, a fuel drier, a combustion chamber and a turbine, the arrangement being such that the compressed air is fed partly to the fuel drier and partly direct to the combustion chamber in which the dried fuel is burnt, and the turbine is fed with combustion gases from the combustion , chamber and the whole of the water content of the fuel. The plant shown comprises a compressor 1 driven by a turbine 3 which supplies the air heated by compression to a combustion chamber 4 and a fuel drier 5. Part of the combustion gases are taken off at 4a and led to the drier 5 to which the water bearing fuel is supplied through an inlet 6. The heated air and combustion gases evaporate some or all of the water content of the fuel which is separated from the solid fuel in the separator 7. The solid fuel together with a small part of the gaseous constituents is delivered directly to the combustion chamber 4 where it is burnt in the air supplied by the compressor 1. The greater part of the gaseous constituents are led through a heat exchanger 8 into the combustion chamber downstream of, the primary zone to cool the chamber walls. The heat exchanger is heated by the exhaust gases of the turbine 3. The quantity of air supplied to the combustion chamber 4 is at least that required for a stoichiometric air-fuel ratio but the quantity supplied to the drier 5 will vary with the water content of the fuel. For low water contents a small quantity of combustion gases would be extracted at 4a and a large quantity of air will then flow through the drier 5. For high water contents, a large quantity of combustion gases would be necessary and the air flow through the drier 5 reduced. The quantities of air and recirculated gas fed to the drier may be such that the temperature of the gaseous constituents at the entry to the heat exchanger corresponds to the dew point. In a modification, the heat exchanger 8-is omitted. As described in Specification 666,692, the fuel supply to the drier may be preheated and partially dried by means of the exhaust gases of the heat exchanger 8. Additional water may be introduced to lower the inlet temperature to the turbine. When using fuel of low moisture content, the gases from the separator 7 may be led through the exchanger 8 direct to the primary combustion zone. In an alternative embodiment, the gases from the exchanger 8 may be mixed with the gases in the duct between the combustion chamber outlet and the turbine. Specifications 701,516 and 701,517 also are referred to.