Optimization research on cooler heat recovery in S-CO2 coal-fired power generation system
The cooling process of the S-CO2 cycle is heat released with variable temperatures.Thus,the cooler heat recovery method with air as a heat transfer medium can effectively improve the thermal efficiency of the system.When the cooler heat recovery is applied to S-CO2 coal-fired power generation,the residual heat absorption in the tail flue is a crucial problem.To solve this problem,based on the recompression cycle with reheating and intercooling,the dual-channel tail flue and cooler heat recovery method are applied,which enables the air in air preheat to absorb the flue gas heat in a wider temperature zone,and the residual flue heat absorption of the boiler is improved.When the main vapor parameters of the S-CO2 cycle are 620℃ and 30 MPa,compared to a single channel in the tail flue and heat recovery method,the thermal efficiency can be improved from 51.95％(RC+RH+IC+CHR)to 52.36％(RC+RH+IC+DCHR).To further optimize the coupling relationship between the cooler heat recovery and the residual flue gas absorption,the original cooler flow reduction method(CFR)is proposed herein,and the split method is introduced to prove the effectiveness of the CFR.The results show that the regenerative degree of the system is improved,and the ratio of a cycle with 100％efficiency is increased by the CFR.Finally,the cycle thermal efficiency is increased from 51.95％(RC+RH+IC+CHR)to 52.52％(RC+RH+IC+DCHR+CFR).
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