R23/R22 Separation and Recovery Using the DIST-PSA Hybrid System

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• 作者：Qiang Fu ; Yan Zhou ; Yuanhui Shen ; Haiyu Yan ; Dongdong Li ; Yingjie Qin ; Donghui Zhang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：56
• 期：1
• 页码：331-341
• 全文大小：763K
• ISSN：1520-5045

文摘

Trifluoromethane (R₂₃), a ubiquitous byproduct of chlorodifluoromethane (R₂₂) synthesis, is one of the most potential greenhouse gases. The encouraged approach is thermal oxidation to process the vent gas by the clean development mechanism (CDM). Though such an approach could avoid the adverse environmental impacts, it will result in a great economic loss that includes not only the incineration cost but also the waste resource of R₂₃. R₂₃ is valuable as a refrigerant, fire suppression agent, and plasma etchant (purity: 99.999 mol %). In this work, the distillation-pressure swing adsorption (DIST-PSA) process was employed to concentrate R₂₃ from 88% to 99.999% in the vent gas economically. Dynamic breakthrough experiments were performed to predict the adsorbent separation performance. Results indicated the coconut activated carbon (SAC-1) is appropriate material for R₂₃ and R₂₂ separation. The SAC-1 has a high separation factor value for R₂₂ and R₂₃ under the experimental conditions. Afterward, the DIST-PSA hybrid system was studied by process simulation and their energy consumption was analyzed. According to the comprehensive analysis, the best performance is obtained with a feed composition of 88% R₂₃/12% R₂₂ for the PSA unit. Process simulation predicts R₂₃ recovery, purity, and energy consumption, respectively, of 69.52%, 99.9993% and 99.59 kJ·kg^–1 R₂₃. Overall, our studies have revealed that coupling a PSA unit with distillation is a feasible and promising technique to separate high-purity R₂₃ efficiently and economically in the R₂₂ synthesis industries.