Closed-cycle gas turbine chemical processor

#The present invention relates to gas turbines and, more particularly, to gas turbines employed for chemical processing.

#Gas turbines are well known for their use in the production of mechanical energy which may be applied to such tasks as vehicle propulsion or power generation. Gas turbines normally burn fuel in an open cycle in which air is compressed in a compressor, then heated by burning fuel in a combustor. The heated air and products of combustion are impinged on blades of one or more turbine wheels before being exhausted to the atmosphere. The turbine wheels are rotated by the energetic hot gases and the rotational energy is coupled to a load as well as back to the compressor.

#In my prior U.S. patent application Ser. No. 263,316, filed May 13, 1981, I disclosed a closed-cycle gas turbine system in which pure oxygen, fed to the combustor together with fuel and recycled exhaust from the turbine, produces a relatively high percentage of carbon dioxide in this closed system. A part of the exhaust stream is bled off to maintain the internal inventory of materials constant in the closed system and the carbon dioxide in the bled off portion is recovered for chemical or industrial use. Excess energy from the gas turbine is employed to generate electric power as an economic output commodity. Heat from the gas turbine exhaust is recovered in a heat recovery steam generator to be used either for the generation of additional electric power or as an economic commodity itself.

#FIG. 1 is a simplified schematic diagram of a closed-cycle gas turbine chemical processor according to an embodiment of the present invention.

#FIG. 2 is a cross section of a combustor of the chemical processor of FIG. 1.

#FIG. 3 is a more detailed schematic diagram of a closed-cycle gas turbine chemical processor according to an embodiment of the invention.

#In my above-referenced prior application, it is necessary to use pure oxygen with the fuel and vitiated recycled gases fed to the combustor in order to obtain satisfactory combustion of the fuel. This also requires attention to the fact that the molecular weight of the hot gases passing to the turbine, being almost pure carbon dioxide, is much higher than the normal gases for which existing turbines are designed. One solution is to inject steam into the compressor or combustor to dilute the carbon dioxide with the steam which has a lower molecular weight than does the carbon dioxide. This solution suffers from the reduced thermodynamic efficiency produced by steam injection. Another solution is to run the gas turbine at a slower speed. This is inconvenient if electric power output from an electric generator being driven by the gas turbine is required to match the frequency of a power grid operating at, for example 60 Hz. That is, if the turbine is slowed to 3000 RPM, for example, gearing is necessary between it and the electric generator to effect drive of the electric generator at 3600 RPM.

#The air normally fed to a gas turbine combustor has three functions, namely:

#burning the fuel