Supercritical carbon dioxide power generation system and method based on natural gas waste heat recovery

Abstract

The invention provides a supercritical carbon dioxide power generation system and method based on natural gas waste heat recovery. The supercritical carbon dioxide power generation system comprises anair separation device, a combustor, a carbon dioxide turbine, a heat regenerator, a water separator, a first carbon dioxide pressurization device, a carbon dioxide recovery device, a waste-heat-recovery heat exchanger, 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 supercritical carbon dioxide power generation system, natural gas is taken as fuel, and the full capture of carbon dioxide is achieved by adopting an oxygen-enriched combustion method; in the carbon dioxide turbine, carbon dioxide expands to the subcritical state and achieves a higher expansion ratio than that the supercritical carbon dioxide Brayton cycle, so that the carbon dioxide turbine can do more workand the cycle efficiency can be improved; and during the bottom cycle, waste heat of the supercritical carbon dioxide cycle is recovered by adopting the Kalina cycle, and the concentration of a working medium changes in the working medium phase-change non-isothermal process and cycle process, so that the vaporization process and the heat-source heat release process can be matched well, the irreversible loss in the heat exchange process can be reduced, and the waste heat utilization efficiency can be improved.

Description

technical field [0001] The invention belongs to the technical field of supercritical carbon dioxide power generation, and in particular relates to a supercritical carbon dioxide power generation system and method for recovering natural gas waste heat. 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 temperatur...

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Problems solved by technology

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

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