Supercritical CO2 combined heat and power generation system and method integrated with multi-stage compression heat pump

Abstract

The invention provides a supercritical CO2 combined heat and power generation system and method integrated with a multi-stage compression heat pump, the supercritical CO2 combined heat and power generation system comprises a supercritical CO2 cycle power generation system, an outlet of a main compressor is sequentially communicated with a low-temperature heat regenerator, a high-temperature heat regenerator, a boiler and a turbine, and an outlet of a precooler is communicated with an inlet of the main compressor; an inlet of the auxiliary compressor communicates with a hot side outlet of the low-temperature regenerator, and an outlet of the auxiliary compressor communicates with a cold side outlet of the low-temperature regenerator. The multi-stage compression heat pump assemblies in the heat supply system are connected in series stage by stage, the hot ends of the multi-stage compression heat pump assemblies communicate with the supercritical carbon dioxide cycle power generation system, and the cold ends of the multi-stage compression heat pump assemblies communicate with the condenser. The multi-stage compression heat pump is adopted to recover waste heat of the cold end, so that irreversible loss of heat transfer is greatly reduced, quality-divided gradient utilization of energy is achieved, and the energy utilization efficiency of the system is greatly improved. In addition, thermoelectricity decoupling can be achieved, and the operation flexibility of the system is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of power generation, and relates to a supercritical CO2 integrated multi-stage compression heat pump 2 Combined heat and power systems and methods. Background technique [0002] With the advantages of high thermal efficiency, compact structure, low investment and low operation and maintenance costs, the supercritical carbon dioxide power cycle system is expected to replace the traditional steam Rankine cycle and greatly improve the power generation efficiency of coal-fired units, thereby reducing pollutants and carbon dioxide emissions. However, the heat release temperature at the cold end of the supercritical carbon dioxide power cycle power generation system is relatively high, and the temperature of the working fluid at the inlet of the cooler is above 90 °C. This part of the heat is taken away by the cooling medium and released into the environment, causing a large amount of energy loss. In order to red...

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Problems solved by technology

Although the working fluid temperature at the inlet of the precooler is relatively high, the outlet temperature is relatively low at about 32°C

In order to fully recover the waste heat at the cold end, the evaporation temperature of the single-stage heat pump needs to be lower than the inlet working fluid temperature of the precooler, so that the evaporation temperature is lower and the COP of the heat pump is lower, resulting in increased power consumption of the heat pump and a lower utilization level of waste heat at the cold end

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