直接式超临界二氧化碳再压缩塔式光热发电系统关键参数优化

Optimization of key parameters of direct supercritical carbon dioxide recompression tower solar thermal power generation system

基于国内外研究现状,建立了直接式超临界二氧化碳(S-CO_(2))再压缩塔式光热(SPT)发电系统模型,研究分析透平/主压缩机进口温度和进口压力对各子系统以及SPT集成系统总㶲损率的影响规律。基于正交阵列,通过遗传算法进行参数优化,以获得最小的系统总㶲损率,同时对第5次优化参数下的模型进行夏至日白天的时间序列计算。结果表明:透平最佳进口压力达到给定范围上限,透平最佳进口温度在784~841℃内,主压缩机最佳进口压力在7.68~10.00 MPa内,最佳分流系数在0.25~0.32之间;系统总㶲损率(SPT集成系统)最小值在70.72%~76.87%内,说明最佳循环低压并不一定要接近临界压力,最佳循环高温并不一定越高越好;不同时刻,系统总㶲损率由集热子系统㶲损率决定,8:00—11:00和16:00—18:00,定日镜㶲损率对其影响较大,11:00—15:00,吸热器㶲损率对其影响较大。本文研究结果可为S-CO_(2)塔式光热发电系统优化设计提供一定参考。

On the basis of the research status at home and abroad,a direct supercritical carbon dioxide(S-CO_(2))recompression tower solar thermal(SPT)power generation system model was established,and the effects of turbine/main compressor inlet temperature and inlet pressure on each subsystem and the SPT integrated system were analyzed.Based on the orthogonal array,genetic algorithm is utilized to optimize the parameters to obtain the smallest total exergy loss rate of the system.Moreover,the model with the fifth optimization parameters is calculated for the summer solstice day and day time series.The results show that,the best turbine inlet pressure reaches the upper limit of the given range,the best inlet temperature of the turbine is within 784~841℃,the best main compressor inlet pressure is within 7.68~10.00 MPa,the best split coefficient is 0.25~0.32.The minimum total exergy loss rate of the system(SPT integrated system)is 70.72%~76.87%,it shows that the optimal cycle low pressure does not necessarily have to be close to the critical pressure,and the optimal cycle high temperature does not necessarily have to be as high as possible.At different times,the total exergy loss rate of the system depends on the exergy loss rate of the heat collection subsystem.At 8:00—11:00 and 16:00—18:00,the heliostat exergy rate has a greater influence on the total exergy loss rate of the system,while at 11:00—15:00,the exergy loss rate of the heat sink has a greater influence.The research results can provide a reliable reference basis for optimization design of S-CO_(2) tower solar thermal power generation system.