COMBINED-CYCLE COGENERATION PROCESS AND COMBINED- CYCLE PLANT IMPLEMENTING IT Russian patent published in 2001 - IPC

FIELD: power engineering; heat and power cogeneration. SUBSTANCE: combined-cycle process includes following sequential operations: smaller portion of working medium escaping from the only or the last compressor of gas-turbine section of plant is conveyed to solid fossil fuel gasifying system; in the process, feedwater is also supplied from steam-turbine section of plant; this water is converted into steam due to gasification which is used in system and then returned to steam- turbine section of plant, primarily to heated side of heat-transfer apparatus; gasifying system is charged with solid fuel, primarily coal, whose gasification results in production of combustible generator gas passed simultaneously to gas-turbine section heaters; generator gas is supplied to second heater and, say, to third one through pressure-reducing units that function to bring working- medium pressure in gas-turbine section of plant to value close to pressures of generator gas and oxidizer coming to mentioned heaters, oxidizer being passed from heater mounted upstream of turbine. At least one of working-medium heaters incorporated in gas-turbine section of plant may be supplied with additional amount of gaseous or liquid fossil fuel from external source. Combined-cycle plant implementing proposed process has working-medium outlet of the only or the last compressor in gas-turbine section communicating with solid-fuel gasifying system whose main pieces of equipment (such as gasifier, gas coolers, and fuel treatment bin) are connected to feedwater pipeline running from steam-turbine section of plant to heated side of heat- transfer apparatus; they are also connected to gas-steam superheater on heated side of heat-transfer apparatus; generator gas outlet provided in gasifying system communicates with gas inlet of working-medium heater in gas-turbine section of plant and also, through pressure-reducing unit, with gas inlets in second and, say, third working-medium heaters of gas-turbine section of plant. Working-medium steam-phase outlet of steam-turbine section of plant communicating with gas-steam superheater on heated side of heat-transfer apparatus may be connected to working-medium inlet in first working cylinder of steam turbine through heated side of preheater mounted in one of gas- turbine section heaters; working-medium outlet of steam-turbine first working cylinder in steam-turbine section of plant communicates with its second working cylinder inlet through heated side of reheater mounted in one of working-medium heaters of gas-turbine section. At least one of working- medium heaters incorporated in gas-turbine section of plant may be provided with additional source of gaseous or liquid fossil fuel. Three alternatives of combined-cycle plant are proposed. EFFECT: improved performance characteristics of plant. 5 cl, 8 dwg