Abstract The potential of an ultrapermeable benzotriptycene-based polymer of intrinsic microporosity (PIM-TMN-Trip) for the upgrading of biogas is investigated. Permeation experiments were performed using an in-house bespoke permeation unit for pure gases and gas mixtures, and included tests with model mixtures as well as real biogas from a sewage treatment plant, under dry and humid conditions. Permeability and CO2/CH4 selectivity for either pure gases or for real biogas were high and lie close to or on the recently defined 2019 Robeson upper bound based on ideal permselectivities. In addition, a remarkable increase in CO2/CH4 selectivity was observed after two weeks of continuous exposure to CO2 due to a significant decrease of CH4 permeability. The constant CO2 permeability and increased selectivity upon ageing suggest that ageing in the presence of CO2 causes a rearrangement, rather than a reduction of the fractional free volume. The mixed gas permeability experiments were performed with high stage-cut in order to mimic a real separation process, and the results confirmed the potential of PIM-TMN-Trip membranes for biogas upgrading.

中文翻译：

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使用基于固有微孔 PIM-TMN-Trip 超渗透聚合物的膜升级原始沼气

摘要 研究了具有固有微孔性的超渗透苯并三苯环聚合物 (PIM-TMN-Trip) 在沼气升级方面的潜力。渗透实验是使用内部定制的纯气体和气体混合物的渗透装置进行的，包括在干燥和潮湿条件下使用模型混合物以及来自污水处理厂的真实沼气进行的测试。纯气体或实际沼气的渗透率和 CO2/CH4 选择性都很高，接近或接近于最近定义的基于理想渗透选择性的 2019 Robeson 上限。此外，由于 CH4 渗透性显着降低，在连续暴露于 CO2 两周后观察到 CO2/CH4 选择性显着增加。老化时恒定的 CO2 渗透率和增加的选择性表明，在 CO2 存在下老化会导致重排，而不是减少部分自由体积。为了模拟真实的分离过程，混合气体渗透率实验以高分段进行，结果证实了 PIM-TMN-Trip 膜在沼气升级方面的潜力。