Rubbery siloxane membranes are utilized in industry for the rejection of nitrogen and for the concentration of heavy hydrocarbons in the membrane permeate stream. In this work, modified crosslinked siloxane terpolymer (VinylMeSiO)_p(Me₂SiO)_m(OctMeSiO)_n membranes (Ter-PDMS) were fabricated and evaluated for separations of heavy hydrocarbon (C₃₊) from natural gas. Gas permeation properties were evaluated using pure gas and C₃₊ hydrocarbon rich multicomponent gas mixtures under varying operating conditions (e.g. feed pressure, temperature, and feed gas composition). Pure gas permeation properties for modified crosslinked siloxane Ter-PDMS membranes displayed enhanced C₃₊/CH₄ ideal selectivity and lessened permeability compared to conventional crosslinked PDMS membrane. Moreover, modified crosslinked siloxane Ter-PDMS membranes also showed enhanced C₃₊ separation performance under simulated typical field gas testing conditions (i.e. feed pressures up to 800 psi for multicomponent gas mixture consisting C₁-C₅ hydrocarbons, CO₂, N₂, and toluene/xylene). At 800 psi, modified crosslinked siloxane Ter-PDMS membrane exhibited C₄H₁₀/CH₄ mixed gas selectivity and C₄H₁₀ permeability of 17.2 and 15100 Barrer, respectively. These results emphasize the observations that membrane separation performance is strongly related to the testing conditions and feed compositions, highlighting the importance of exploring and designing better modified rubbery siloxane membrane materials for the actual industrial process.

橡胶状硅氧烷膜在工业上用于除去氮和浓缩膜渗透物流中的重烃。在这项工作中，制造了改性的交联硅氧烷三元共聚物（VinylMeSiO）_p（Me ₂ SiO）_m（OctMeSiO）_n膜（Ter-PDMS），并评估了天然气中重烃（C ₃₊）的分离。使用纯气和富含C ₃₊烃的多组分气体混合物在不同的操作条件（例如进料压力，温度和进料气体组成）下评估了气体的渗透性能。改性交联硅氧烷Ter-PDMS膜的纯气体渗透性能显示出增强的C ₃₊与传统的交联PDMS膜相比，/ CH ₄理想的选择性和降低的渗透性。此外，改性的交联硅氧烷Ter-PDMS膜在模拟的典型现场气体测试条件下（即，对于由C ₁ -C ₅烃，CO ₂，N ₂组成的多组分气体混合物的进料压力高达800 psi）也显示出增强的C ₃₊分离性能。和甲苯/二甲苯）。在800 psi的压力下，改性的交联硅氧烷Ter-PDMS膜表现出C ₄ H ₁₀ / CH ₄混合气体选择性和C ₄ H ₁₀渗透率分别为17.2和15100 Barrer。这些结果强调了观察结果，即膜分离性能与测试条件和进料组成密切相关，突出了为实际工业过程探索和设计更好的改性橡胶状硅氧烷膜材料的重要性。