面向余热回收的超临界CO_(2)动力循环高级[火用]分析  

Advanced Exergy Analysis of a Supercritical CO_(2)Power Cycle for Waste Heat Recovery

作　　者：姜悦茂 王顺森[1] 吴杰鹏 颜晓江 宋立明[1] JIANG Yuemao;WANG Shunsen;WU Jiepeng;YAN Xiaojiang;SONG Liming(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2024年第2期43-55,共13页Journal of Xi'an Jiaotong University

摘　　要：针对常规[火用]分析方法不能揭示部件总[火用]损中那部分是由自身不可逆性造成的以及有多少可以通过优化而避免的问题,对面向余热回收的超临界CO_(2)动力循环进行了高级[火用]分析,找出[火用]损来源,探究部件真实提升潜能。首先,从热力学、经济与紧凑性3个角度对回热式循环余热回收系统进行了多目标优化,进行了热经济与常规[火用]分析;继而,将每个部件的[火用]损细分为内源可避免、内源不可避免、外源可避免与外源不可避免4部分,进行了高级[火用]分析;最后,比较了常规[火用]与高级[火用]分析结果,揭示了常规[火用]分析方法的局限性。结果表明,经优化后系统净发电量、平准化度电成本与单位功率面积分别为6.24 MW、4.48美分/(kW·h)与0.19 m^(2)/kW;回热器总[火用]损率最高,约为36.7%。由于关键设备技术限制,系统极限[火用]效率相比理想工况低约7%,系统总[火用]损主要由部件自身不可逆性产生,其中有42.9%可通过部件改进而减少。在不同燃机工况下,透平具有最高的内源可避免[火用]损率。Aiming at the issue that conventional exergy analytic methods cannot disclose which part in the total exergy destruction of components is caused by their own irreversibility and how much can be avoided by improving the components,advanced exergy analysis of a supercritical CO_(2)power cycle for waste heat recovery is conducted to find out the cause of the exergy destruction and determine the actual improvement potential of components.Firstly,a multi-objective optimization of a recuperated layout waste heat recovery system is carried out from the aspects of thermodynamics,economy and compactness,and a thermoeconomic and exergy analyses are also performed.Then,the exergy destruction of each component is divided into four parts:endogenous avoidable,endogenous unavoidable,exogenous avoidable and exogenous unavoidable,and an advanced exergy analysis is performed.Finally,a comparison of the results of conventional and advanced exergy analyses shows the limitations of the conventional method.The results show that after optimization,the net electrical generation,LOCE and specific power heat transfer area are 6.24 MW,4.48 cents/(kW·h)and 0.19 m^(2)/kW,respectively.The exergy destruction rate of the recuperator is the highest,at about 37%.Due to technical limitations of key equipment,the exergy efficiency of the unavoidable cycle is reduced by about 7%compared to the ideal condition.The total exergy destruction is mainly caused by the irreversibility of the components themselves and can be reduced by about 43%by improving the efficiency of the components.The turbine has the highest endogenous avoidable exergy destruction rate under different gas turbine operating conditions.

关 键 词：余热回收 超临界CO_(2)动力循环 多目标优化 热经济分析 高级[火用]分析 

分 类 号：TK11[动力工程及工程热物理—热能工程]