ORC发电技术在低温余热回收利用中的性能分析

Performance analysis of ORC power generation technology in low temperature waste heat recovery

关键词:  有机工质  超临界有机朗肯循环  热传递  多因素分析

Key words:  organic working compound  supercritical organic Rankine cycle  heat transfer  multivariate analysis

摘要:

以某炼化厂实际产生的余热作为低温热源,参考低温热源物性及有机工质筛选原则,初选出7种适合该炼化厂低温余热发电的有机工质,以最大净输出功率为目标函数,考察过程的循环热效率、蒸发温度(压力)和废热排放量等工艺参数,对7种工质进行了模拟分析。结果 表明,工质R-600和R-152a在亚临界区域表现性能最佳,在超临界区域工质R-134a也表现出较好的性能,但亚临界有机朗肯循环表现出更好的热力学性能。对超临界和亚临界有机朗肯循环(ORC)过程中蒸发器内热传递过程做了分析,并采用多因素分析方法对ORC系统工质流量、蒸发温度(压力)、膨胀机进气温度和过热度等影响因素做了分析研究,为炼化厂低温余热回收工艺设计提供参考。 

Abstract:

Taking the actual production parameter of a refinery as the low temperature heat source, seven organic working compounds for the low temperature heat power generation of this refinery were selected, based on the low temperature heat source’s physical property and organic working compounds screening principle. Seven refrigerants were simulation analyzed by taking the maximum net output power as the objective function, and the effects of thermal efficiency, evaporation temperature (pressure), heat emission and other technological parameters were investigated. The results show that the refrigerant R-600 and R-152a have the best performance in subcritical region, while refrigerant 134a shows a good performance in supercritical region. In general, the subcritical organic Rankine cycle(ORC) showed a better thermodynamic performance. By analyzing the evaporator’s heat transfer process in both subcritical and supercritical ORC, and analyzing the influence factors of refrigerant flow rate, evaporation temperature (pressure), expander inlet air temperature and superheat degree of ORC system through multiple factor analysis method, this study provides the reference for the design of low temperature waste heat recovery process in refinery.