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

摘要

An integrated coal gasification plant and combined cycle system employs a supply of compressed air 68 bled off at an intermediate pressure from an air compressor 28 min portion of a gas turbine 12 min to supply the compressed-air needs of an oxygen plant 20 associated with the coal gasification plant 16. The high-temperature exhaust 38 from the turbine section 32 of the gas turbine is employed to generate steam in a heat recovery steam generator 40 min . The steam drives a steam turbine 42 to produce additional mechanical output. In order to compensate for the removal of the compressed air 68 fed to the oxygen plant 20, the spent steam 70 from the steam turbine 42 is added to the compressed air and fuel in the combustor portion 30 min 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 recovery steam generator. The release of steam through the gas turbine, and other disclosed techniques, permits the use of a non-condensing system and thus 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.