Department of Chemical and Biological Engineering , University at Buffalo, The State University at New York , Buffalo , New York 14260 , United States.
ACS Appl Mater Interfaces. 2019 Mar 20;11(11):10933-10940. doi: 10.1021/acsami.9b01079. Epub 2019 Mar 5.
Membrane materials for CO removal from natural gas are based on glassy polymers with a high CO/CH diffusivity selectivity. However, these polymers suffer from competitive sorption by heavy hydrocarbons that decreases CO permeability and physical aging that reduces gas permeability with time. We circumvent these issues by designing rubbery, solubility-selective polymers with a ratio of ether/ester oxygen to carbon as high as 0.8 through the use of 1,3-dioxolane and 1,3,5-trioxane. The ether/ester oxygen groups interact favorably with CO but do not interact with CH, leading to a high CO/gas solubility selectivity that is unaffected by heavy hydrocarbons in the raw natural gas. These polar groups are incorporated in short branches to yield an amorphous and rubbery nature, leading to high gas permeability that is stable over time. A polymer with an O/C ratio of 0.71 (P71) shows a mixed-gas CO permeability of 320 Barrers and a CO/CH selectivity of 21 in the simulated natural gas at 50 °C, which is independent of the hexane content and above the upper bound for CO/CH separation at 50 °C.
用于从天然气中去除 CO 的膜材料基于具有高气态 CO/CH 扩散选择性的玻璃态聚合物。然而，这些聚合物受到重质烃的竞争吸附，这降低了 CO 的渗透性，并且随着时间的推移发生物理老化，从而降低了气体的渗透性。我们通过使用 1,3-二恶烷和 1,3,5-三恶烷，将醚/酯氧与碳的比例设计高达 0.8，从而设计出具有橡胶状、溶解选择性的聚合物，从而规避了这些问题。醚/酯氧基团与 CO 有利相互作用，但与 CH 不相互作用，导致高气态 CO/气体溶解度选择性不受原料天然气中重质烃的影响。这些极性基团被纳入短支链中，以产生非晶态和橡胶态，从而导致高气密性，并且随着时间的推移保持稳定。O/C 比为 0.71（P71）的聚合物在 50°C 的模拟天然气中表现出混合气体 CO 渗透性为 320 巴，CO/CH 选择性为 21，这与己烷含量无关，并且高于 50°C 时 CO/CH 分离的上限。
