Polymeric membranes with intrinsic microporosity have been at the center of attention for gas separation applications since the introduction of PIM-1. This study utilizes atomistic simulations to model and to understand the pure- and mixed-gas transport properties of PIM-1 for the CO₂/CH₄ gas pair. Monte Carlo and molecular dynamics methods were combined in the estimation of sorption and diffusion of CO₂ and CH₄ in PIM-1. Simulated sorption and permeability data compared very well with experimental reports. Mixed-gas adsorption simulations proved the existence of competitive adsorption, favoring CO₂, hence resulting in an increase in solubility selectivities. However, in mixed-gas environment CH₄ permeabilities increased significantly compared to pure gas conditions, overall decreasing perm-selectivities of the polymer. Plasticization of the polymer around 25 bar CO₂ partial fugacity was apparent both in pure- and mixed-gas conditions. Simulations at different gas feed compositions proved the dependence of competitive sorption and CO₂-induced swelling in partial feed gas fugacities. Simulation results were combined to obtain a macroscopic permeability model that relates the multicomponent permeability to the permeate pressure and composition. Accurate estimations of permeabilities by the model were achieved allowing future implementation of the model in process simulation tools.

自从引入 PIM-1 以来，具有固有微孔性的聚合物膜一直是气体分离应用的关注焦点。本研究利用原子模拟来模拟和了解 PIM-1 对 CO ₂ /CH ₄气体对的纯气体和混合气体传输特性。蒙特卡罗和分子动力学方法相结合，用于估计PIM-1中 CO ₂和 CH ₄的吸附和扩散。模拟的吸附和渗透率数据与实验报告进行了很好的比较。混合气体吸附模拟证明了竞争吸附的存在，有利于 CO ₂，因此导致溶解选择性的增加。然而，在混合气体环境 CH₄与纯气体条件相比，渗透率显着增加，聚合物的渗透选择性总体下降。聚合物在 25 bar CO ₂部分逸度下的增塑在纯气体和混合气体条件下都很明显。不同气体进料组成的模拟证明了部分进料气体逸度中竞争性吸附和CO ₂诱导的膨胀的依赖性。综合模拟结果以获得宏观渗透率模型，该模型将多组分渗透率与渗透压力和成分联系起来。实现了模型对渗透率的准确估计，允许未来在过程模拟工具中实施模型。