Abstract: An exothermic chemical process carried out above atmospheric pressure, in which a first pressurized gas stream from the process and a second pressurized fluid stream containing an excess of high temperature heat from the process is passed through a heat exchanger to heat the first pressurized gas with a portion of the excess high temperature heat, and the heated first pressurized gas is expanded to generate work. An additional amount of pressurized gas and at least a portion of the second pressurized fluid stream is passed through a heat exchanger to heat the additional amount of pressurized gas with another portion of the excess high temperature heat contained in the second pressurized fluid stream, with the additional amount of pressurized gas being independent to the amount required or produced by the process.

Abstract: Process and apparatus for a hydrocarbon conversion process, for example thermal cracking, in which feedstock is converted in a heated furnace, the furnace being heated by burning a mixture of fuel and preheated air. The preheated air is obtained by passing air through successive compression, heating and gas turbine expansion zones, the work thereby obtained from the gas turbine expansion zone being used, at least in part, to compress hydrocarbon process gas produced in the furnace.