关键词: 热力学性质, 有机朗肯循环, 内回热器, 热力性能, 工质, 模拟, (火用)

Abstract: Most studies on the comparison of organic Rankine cycle(ORC) without internal heat exchanger(IHE) and ORC with internal heat exchanger(IORC) mainly focused on thermal performance changes with the initial parameters, but researches on the comparison based on heat absorption amount are rare. This paper established two systems, ORC without IHE and IORC, with the flue gas as the heat source. Based on the heat absorption amount change with changing the parameter of heat source, the regularity of changes of inlet temperature, net work, heat consumption and exergy loss in the two systems mentioned were analyzed with ten selected fluids, and the better working fluids and their compatibilities with internal heat exchanger showed up. The results showed that when the heat source enters the system at 150℃ and exits between 70℃ to 90℃, plus the pinch temperature keeps at 10℃, IORC is more suitable for the low heat absorption amount area;in the high area, IORC increases little in the thermodynamic performance, and sometimes IORC performs even worse than non-IHE ORC;Through comprehensive comparison, R236ea and R600a are the best choices, and R245fa and R600 are relatively suitable fluids;The difference of thermodynamic performance between the two systems using R123 as working fluid is little, the maximum difference of the heat consumption and net work between IORC and ORC system is only about 600kJ/kg and 2kW, and R123 have worse thermal compatibility with internal heat exchanger.

Key words: thermodynamic properties, organic Rankine cycle, internal heat exchanger, thermodynamic performance, working fluid, simulation, exergy