to the extent that the reaction is exothermic it has been suggested that the steam equipment could be eliminated by using a gas turbine connected directly to the output of a sulfur burning furnace so that the combustion products of the sulfur furnace could be expanded directly through the gas turbine however this approach has been avoided because of the corrosive nature of the product gas in searching for an approach which could utilize a gas turbine while avoiding the introduction of corrosive gas into a turbine the embodiment of fig2 was discovered in the prior art fig2 shows an air turbine cycle which includes an air compressor 60 which is driven by an air turbine 64 through an interconnecting shaft 66 the air turbine 64 may also drive an electrical generator or other load 68 through a connecting shaft 70 a furnace 72 is provided with fuel 74 such that combustion occurs within the furnace to produce a hot exhaust gas stream or product gas on line 76 the hot exhaust gas stream is input into a heat exchanger 80 where it passes in a heat exchange relation with compressor discharge air on line 82 whereupon hot air is provided on line 84 to the air turbine inlet the hot air is expanded through the air turbine to drive a bladed rotor not shown which in turn drives the compressor and the electrical generator the turbine exhaust is output on line 86 whereupon it is input into the furnace 72 for providing heated air to the combustion furnace the prior art therefore includes an air turbine 64.