Thermal stability of some hydrofluorocarbons as supercritical ORCs working fluids
Thermal stability of some hydrofluorocarbons as supercritical ORCs working fluids
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DOI：
10.1016/j.applthermaleng.2017.09.046
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发表时间：
2018-01
影响因子：
6.4
通讯作者：
Xiaoye Dai;Lin Shi;Qingsong An;W. Qian
中科院分区：
文献类型：
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作者：
Xiaoye Dai;Lin Shi;Qingsong An;W. Qian
有机朗肯循环 (ORC) 用于在可再生能源和工业废热回收系统中发电。超临界 ORC 最近因其较高的热效率和火用效率而引起了人们的广泛兴趣。氢氟碳化合物用作亚临界 ORC 的工作流体，由于其良好的热性能，也是超临界 ORC 的良好选择。然而，在超临界 ORC 中，必须考虑氢氟碳化合物在高温下的热稳定性。本研究采用氟离子浓度作为氢氟碳化合物分解的指标。设计了测试系统，实验测量了HFC245fa、HFC152a、HFC134a、HFC236fa和HCFC123的分解温度。然后分析了氢氟碳化合物的热稳定性和分子结构之间的关系。结果表明，从热稳定性角度来看，这些氢氟碳化合物是超临界 ORC 的良好选择。文中还分析了氢氟碳化合物的分解特性以及分解产物对测试系统的影响。
Organic Rankine Cycles (ORC) are used to generate electricity in renewable energy and industrial waste heat recovery systems. Supercritical ORCs have recently attracted much interest due to their higher thermal and exergy efficiencies. Hydrofluorocarbons are used as working fluids in subcritical ORCs and are also good choices for supercritical ORCs due to their good thermal performance. However, the thermal stability of the hydrofluorocarbons must be considered at high temperatures in supercritical ORCs. This study used the fluoride ion concentration to be the indicator of hydrofluorocarbon decomposition. A test system was designed and decomposition temperatures of HFC245fa, HFC152a, HFC134a, HFC236fa and HCFC123 were measured experimentally. The relationships between thermal stability and molecular structures of hydrofluorocarbons were then analyzed. The results show that these hydrofluorocarbons were good selections for supercritical ORCs by thermal stability. The hydrofluorocarbon decomposition characteristics and the effects of the decomposition products on the test system were also analyzed in this paper.