Integrated coal gasification plant and combined cycle system with air bleed and steam injection

Abstract

An integrated coal gasification plant and combined cycle system employs a supply of compressed air bled off at an intermediate pressure from an air compressor portion of a gas turbine to supply the compressed-air needs of an oxygen plant associated with the coal gasification plant. The high-temperature exhaust from the turbine section of the gas turbine is employed to generate steam in a heat recovery steam generator. The steam drives a steam turbine to produce additional mechanical output. In order to compensate for the removal of the compressed air fed to the oxygen plant, the spent steam from the steam turbine is added to the compressed air and fuel in the combustor portion of the gas turbine. The unexpended energy in the steam fed to the combustor is recovered by expansion in the turbine of the gas turbine and by absorption in the heat receovery stem generator. The release of steam through the gas turbine, and other disclosed techniques, permits elimination of the capital cost of a condenser and cooling tower which would otherwise be required. In addition, the direct provision of compressed air to the oxygen plant eliminates the capital and operating cost of the separate compressor and electric motor conventionally required to provide such compressed air.

Dependencies are inferred from the claim text.