Thermodynamic analysis of a volatile organic compounds (VOCs) condensation recovery system combined with mixed-refrigerant J-T (MRJT) refrigeration is illustrated in this paper, which provides an effective and economical choice for petroleum plants. VOCs is compressed, cooled by its recuperation process and separated in two simple rectification columns with 3–5 stages. The cooling powers for condensers at column top are provided by a high efficiency dual MRJT refrigerator at 100 K and 232 K, respectively. The cooling and separation characteristics of petroleum VOCs are also analyzed comprehensively. It is indicated that most of VOCs condensation load locates in high temperature region (≥ 235 K approximately). It might be feasible to cool VOCs from 235 K to 110 K by cold purified air through recuperation. For a typical petroleum VOCs, non-methane hydrocarbon residual of 56 mg Nm⁻³ is achieved with specific power consumption (SPC) of 0.1289 kWh Nm⁻³, free of additional purifying units. According to the analysis on the effects of variable VOCs composition and pressure, the cooing loads of top condensers are close related to the performance of VOCs recuperation. C1 and C2 are key components to enhance recuperation at low temperatures and reduce SPC. Exceed C3 could enlarge cold stage condenser load and SPC due degraded cold stage recuperation; while exceed C4-C6 could reduce condenser loads and SPC. Higher VOCs pressure could also decrease SPC.

本文阐述了结合混合制冷剂JT（MRJT）制冷的挥发性有机化合物（VOC）冷凝回收系统的热力学分析，为石油厂提供了一种有效而经济的选择。挥发性有机化合物被压缩，通过其再生过程进行冷却，并在两个具有3-5级的简单精馏塔中分离。塔顶冷凝器的冷却功率分别由100 K和232 K的高效双MRJT制冷机提供。还对石油VOC的冷却和分离特性进行了综合分析。结果表明，大多数VOC的冷凝负荷位于高温区域（约≥235 K）。通过冷却空气将纯净的VOC从235 K冷却到110 K是可行的。对于典型的石油VOC，^在没有附加净化单元的情况下，以0.1289 kWh Nm ^-3的特定功耗（SPC）达到^-3。根据对挥发性有机化合物组成和压力变化的影响分析，顶部冷凝器的冷却负荷与挥发性有机化合物的换热性能密切相关。C1和C2是增强低温下的换热并降低SPC的关键组件。超过C3可能会因冷库换热降级而增加冷库冷凝器负荷和SPC；而超过C4-C6可以减少冷凝器负荷和SPC。较高的VOC压力也可能降低SPC。