Coal gasification supercritical carbon dioxide power generation system and method capable of realizing waste heat recovery

Abstract

The invention provides a coal gasification supercritical carbon dioxide power generation system and method capable of realizing waste heat recovery. The system comprises an air separating device, a burner, a carbon dioxide turbine, a heat regenerator, a water separator, a first carbon dioxide supercharging device, a carbon dioxide recovery device, a waste heat recovery device, a coal gasificationdevice, a Kalina turbine, a Kalina heat regenerator, a first mixer, an ammonia separator, a second mixer, a high-pressure condenser and a gas-liquid separator. According to the system, coal gas is used as fuel, and total capture of carbon dioxide is realized through oxygen-enriched combustion; the carbon dioxide expands to the subcritical state in the turbine, and the expansion ratio is higher than that of supercritical carbon dioxide Brayton cycle, so that the turbine works more, and the cycle efficiency is improved; supercritical carbon dioxide cycle waste heat is recovered through Kalina cycle during bottom cycle, by the aid of change of the working medium concentration in the non-isothermal process and the cyclic process of the working medium phase change, the gasification process andthe heat release process of a heat source are well matched, the irreversible loss of the heat exchange process is reduced, and the waste heat utilization efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of supercritical carbon dioxide power generation, and in particular relates to a coal gasification supercritical carbon dioxide power generation system and method for waste heat recovery. Background technique [0002] Energy and the environment are two major problems facing the development of human society. Continuously improving the efficiency of generator sets is the eternal theme and goal of power industry research. Currently, the more commonly used power cycles include the Rankine cycle with water as the working fluid and the Brayton cycle with air as the working fluid. Conventional coal-fired power plants mainly use the Rankine cycle with water as the working fluid. At present, the initial steam parameters of the largest one-million-kilowatt coal-fired power plant have reached 31MPa and 620°C. The gas turbine mainly uses the Brayton cycle with air as the working medium. At present, the inlet gas temper...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a coal gasification supercritical carbon dioxide power generation system and method with waste heat recovery, which solves the defect that the efficiency of the existing generating units cannot be improved

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