基于多级压缩回热过程的半闭式S-CO_(2)循环回热优化研究  

Research on Regeneration Optimization of Semi-closed S-CO_(2) Cycle Based on Multi-compression Regeneration Process

作　　者：孙恩慧 纪洪福 石嘉豪 张磊[2] 徐进良 李永毅[2] SUN Enhui;JI Hongfu;SHI Jiahao;ZHANG Lei;XU Jinliang;LI Yongyi(Department of Power Engineering,North China Electric Power University,Baoding 071003,Hebei Province,China;Hebei Key Laboratory of Low Carbon and High Efficiency Power Generation Technology(North China Electric Power University),Baoding 071003,Hebei Province,China;Key Laboratory of Power Station Energy Transfer Conversion and System,Ministry of Education(North China Electric Power University),Changping District,Beijing 102206,China)

机构地区：[1]华北电力大学动力工程系,河北省保定市071003 [2]河北省低碳高效发电技术重点实验室(华北电力大学),河北省保定市071003 [3]电站能量传递转化与系统教育部重点实验室(华北电力大学),北京市昌平区102206

出　　处：《中国电机工程学报》2023年第17期6755-6764,共10页Proceedings of the CSEE

基　　金：国家自然科学基金项目(52206010,52076079,52130608);中央高校基本科研业务费专项资金项目(2021MS076,2021MS079)。

摘　　要：在单回热半闭式超临界二氧化碳(supercritical carbon dioxide,S-CO_(2))循环中,CO_(2)在不同温度和压力下的比热容差异较大,导致回热器两侧工质的温度匹配性较差,不可逆损失较大。构建多级压缩回热过程是改善单回热循环回热性能的有效方法。该文在单回热循环的基础上,通过添加分流再压缩过程,提出再压缩半闭式S-CO_(2)循环,并获得6.63%的效率提升,同时从数学公式中证明效率提高的原因是叠加了净功。进一步构建三压缩循环时,发现回热器两侧工质流量的不匹配使得回热器内部出现温度交叉,体现出半闭式S-CO_(2)循环存在多种质量流耦合匹配问题,可通过对燃料、氧气和回流CO_(2)在回热器中进行流量匹配来解决。结果表明,三压缩循环相比再压缩循环的效率可进一步提高1.47%。通过构建多级压缩回热过程,充分挖掘了半闭式S-CO_(2)循环的效率潜力,可获得较好的性能。In the single-compression semi-closed supercritical carbon dioxide cycle,the specific heat of CO_(2) varies greatly at different temperatures and pressures,which leads to poor temperature matching and large irreversible losses of working fluid on both sides of the regenerator.Constructing multi-compression regeneration process is an effective method to improve the regeneration performance.Based on single-compression cycle,the recompression semi-closed S-CO_(2) cycle is proposed by adding a split recompression process,and the cycle efficiency is improved by 6.63%.Meanwhile,it is proved from the mathematical formula that the reason for the efficiency improvement is the superposition of net work.When the triple-compression semi-closed S-CO_(2) cycle is further constructed,it is found that the mismatch of the working fluid mass flow on both sides of the regenerator results in temperature crossover inside the regenerator,indicating there is coupling and matching problem of many flows in the semi-closed S-CO_(2).The problem is solved by matching the mass flow of fuel,oxygen and recycled CO_(2) in the regenerator.The result shows that the cycle efficiency of triple-compression cycle can be further increased by 1.47%compared with recompression cycle.In this paper,the fficiency potential of semi-closed S-CO_(2) cycle is fully explored by constructing the multi-compression regeneration process,and better cycle performance is obtained.

关 键 词：半闭式S-CO_(2)循环 多级压缩回热 循环效率 回热优化 多流匹配 

分 类 号：TK123[动力工程及工程热物理—工程热物理]