烟气余热驱动的CO_2超临界循环优化及分析  

Improvement and analysis of CO_2 super-critical cycle using waste gas from flue gas

作　　者：褚辉 王迅[1] 李成宇 王怀信[1] 

机构地区：[1]天津大学机械工程学院中低温热能高校利用教育部重点实验室,天津300350

出　　处：《化学工程》2017年第12期6-10,共5页Chemical Engineering(China)

摘　　要：文章着眼于初温为600℃的烟气余热回收再利用,以热稳定性良好的CO_2为工质并结合烟气热源的特点,针对CO_2超临界循环(S-CO_2)放热平均温度过高的缺点,在不影响循环吸热量的条件下,提出了改进型过膨胀CO_2超临界循环(SO-CO_2)以及SO-CO_2和有机跨临界循环(OTC)的复合循环(SO-CO_2/OTC)。对2类循环以单位质量流量烟气的循环净输出功W_(net)和系统回收率η_(rec)最大为目标,分别进行了热力学参数优化,并与传统蒸汽朗肯循环相比较。结果表明:以苯为工质的SO-CO_2/OTC热力学性能最优(W_(net)=203.15 k W,η_(rec)=37.06%),SO-CO_2(W_(net)=152.07 k W,η_(rec)=28.01%)相比于S-CO_2(W_(net)=117.11 k W,η_(rec)=21.37%),热力学性能有了较大的提升,但仍不如传统蒸汽朗肯循环(W_(net)=169.21k W,η_(rec)=30.87%)。Using CO_2 as working fluid,two improved thermodynamic cycles were presented,over-expanded CO_2 super-critical cycle( SO-CO2) and a new combined SO-CO_2/OTC based on traits of waste heat and weakness of S-CO_2 driven by 600 ℃ fuel gas. The maximum net power output per unit mass fuel gas W_(net)and system recovery efficiency η_(rec)were selected as objective functions to optimize thermodynamic parameters. Two cycles were then compared with fully H_2O-RC. The results show that SO-CO_2/OTC with benzene( W_(net)= 203. 15 k W,η_(rec)=37. 06%) outperforms other working fluids thermodynamically. Compared with basic S-CO_2( W_(net)= 117. 11 k W,η_(rec)= 21. 37%),SO-CO2( W_(net)= 152. 07 k W,η_(rec)= 28. 01%) achieves an obvious rise,but still beneath H_2O-RC( W_(net)= 169. 21 k W,η_(rec)= 30. 87%).

关 键 词：烟气余热 动力循环 超临界CO2循环 过膨胀超临界CO2循环 复合循环 

分 类 号：TK115[动力工程及工程热物理—热能工程]