再热-抽汽回热-内回热结合的有机朗肯循环热力性能分析

Thermal performance analysis of a combined reheating-regenerative-internal regenerative organic Rankine cycle system

为了提高有机朗肯循环(ORC)的热效率,提出了再热、抽汽回热和内回热3种方式相结合的新型有机朗肯循环系统(新型系统),以有机工质R245fa为研究对象,分析了新型系统热效率和火用损失与循环再热蒸汽压力和汽轮机抽汽压力的关系,并将新型系统在最佳再热蒸汽压力条件下的热力性能分别与单一再热ORC、内回热ORC、抽汽回热ORC、抽汽-内回热ORC系统进行计算比较。结果表明:随着汽轮机抽汽压力的提高,新型系统热效率逐渐增大,但增大趋势趋于平缓,其最佳再热蒸汽压力为1.4 MPa;新型系统为最优系统,其热效率达到18.86%,远高于同参数单一再热ORC和内回热ORC,分别比抽汽回热ORC和抽汽-内回热ORC的系统热效率高2.63%和1.51%。

In order to improve the efficiency of organic Rankine cycle（ORC）,a new organic Rankine cycle system combining reheating,regenerative extraction and internal regenerative cycle was proposed.Taking the organic fluid R245 fa as the research object,the variations of the new system＇s thermal efficiency and exergy loss with the reheating steam pressure and steam extraction pressure were investigated.Moreover,the thermal performance of this new system was compared with that of the single reheating ORC system,the internal regenerative ORC system and the regenerative ORC combining with regenerative-internal regenerative ORC,under the condition with the best reheating pressure.The results show that,there＇s an optimum reheating steam pressure（1.4MPa）and the heat efficiency of the new system gradually increases with the extraction pressure,but the growth rate turns tender.The reheating-regenerative-internal regenerative ORC system has the best thermal performance,and its heat efficiency reaches 18.86%,which is 2.63%and1.51% higher than that of the reheating ORC system and the internal regenerative ORC system with the same level parameters,respectively.