Abstract: The use of hot gas generators which produce corrosive or abrasive products of combustion have precluded the use of gas turbines in a direct flow path of the combustion products. It is preferable to utilize non-contact gas to gas heat exchangers in order to transfer heat from a hot gas stream to a working fluid. A first heat exchanger connected to a gas furnace is used to raise the temperature of an air turbine inlet gas. A second heat exchanger is used to raise the temperature (prewarm) of compressor discharge air to the air turbine air inlet, the second heat exchanger connected to the air turbine exhaust. A third heat exchanger preheats the air input into a furnace.

Abstract: In a coal gasification plant there is a requirement for supplying oxygen to the coal gasifier in order to produce coal gas fuel. An oxygen plant will produce oxygen and nitrogen from an input supply of compressed air. In the presence of a fired gas turbine which is supplied with coal gas fuel, the waste heat from the fired gas turbine may be used to heat compressed air for driving an air cycle turbine. The air cycle turbine in turn drives an air cycle compressor for producing air to the oxygen plant. The nitrogen gas by-product from the oxygen plant is injected into the air cycle for disposal through the air turbine.