超临界二氧化碳动力循环余热利用方案优化研究

Study on optimization of supercritical carbon dioxide power cycle schemes in waste heat utilization

针对燃气轮机余热利用问题,以有回热的超临界二氧化碳(S-CO_(2))动力循环为基础,引入中间冷却、中间再热和分流再压缩技术,建立6种循环方案。分别以S-CO_(2)动力循环的循环效率最高和循环净输出功最大为优化目标,采用遗传算法对各方案的参数进行优化,并对每个方案的优化结果进行经济性比较。结果表明:以循环效率最高为优化目标时,引入一次中间冷却、一次中间再热和一次分流再压缩都能不同程度提高循环效率,其中引入一次分流再压缩和一次中间再热的方案6循环效率最高,达到43.29%;以循环净输出功最大为优化目标时,引入一次中间冷却可以增大输出功,引入一次中间再热会减小S-CO_(2)动力循环净输出功,而一次分流再压缩退化为无分流方案,其中引入一次中间冷却的方案2净输出功最大,为82620.02 kW;6个方案的经济性均在以S-CO_(2)动力循环净输出功最大为优化目标时更具优势,原因在于这种情况下对燃气轮机排烟的余热利用效率更高,其中方案2运行20年收益最大,为50.65亿元。

Aiming at the problem of waste heat utilization of gas turbine,the technologies of intermediate cooling,intermediate reheating and split flow recompression were introduced into the supercritical carbon dioxide(S-CO_(2))power cycle with heat recovery and six cycle schemes were established.Taking the cycle efficiency and the cycle net output power of the S-CO_(2) cycle as the optimization objectives,the genetic algorithm was used to optimize the parameters of each scheme,and the earnings of optimization results were compared.The results show that the cycle efficiency can be improved in varying degrees by introducing one intermediate cooling,one intermediate reheat and one split flow recompression when the optimization goal is to maximize the cycle efficiency.The cycle efficiency of the sixth scheme that introduces one split flow recompression and one intermediate reheat is the highest,which reaches 43.29%.When the optimization goal is to maximize the net cycle output work,the introduction of primary intermediate cooling can increase the net output power,the introduction of primary intermediate reheating can reduce the net output power of the power cycle,and the one split recompression degenerates into no split scheme.The second scheme that introduces primary intermediate cooling has the largest net output power reaching 82620.02 kW.When the cycle net output work is taken as the optimization objective,the economy of the six schemes is more advantageous because the waste heat utilization efficiency of gas turbine smoke exhaust is higher.The second scheme has the largest operating earnings in 20 years,which is RMB 5.065 billion.