Currently, thermal treatments are used extensively to convert millions of tons of biomass and municipal solid waste into energy products. Although biogas represents $\sim$50% of these energy products, usually disposed due to the difficulty to extract CH₄ and H₂ (main flammable compounds) from their complex composition contaminated by CO₂, N₂, etc. Recently, Polyethersulfone (PES) membranes have been employed for that purpose as an effective and cheap technology, however, their permeation properties under higher pressure and temperature are still undefined. Within this context, this research aims to study the influence of high temperatures and pressure on CO₂/N₂, CO₂/H₂ and CO₂/CH₄ selectivity performance of PES membranes and their potential applications in biogas upgrading systems. The experiments were started with preparation of the PES membranes using phase inversion methods, then observing their morphology, physical, chemical, thermal, and mechanical behaviors using SEM, XRD, FTIR, TGA, and universal testing machine. Consecutively, the initial gas separation experiments using CO₂ gas were conducted to determine the maximum pressure and temperatures that the synthesized PES membranes can withstand without being damaged or thermally degraded. Based on the results of initial experiments, CO₂/CH₄, CO₂/N₂, and CO₂/CH₄ selectivity of the PES membranes was measured up to 60 °C and 6 bar (absolute pressure) using a set-up built especially for that purpose. Also, the effect of separation temperature and pressure on the separation mechanism were studied. The results revealed that the lowest pressure (1 bar) and the highest temperature (60 °C) can help to achieve the maximum selectivity performance for CO₂/N₂ (0.91), CO₂/H₂ (1.25), and CO₂/CH₄ (3.07), with improvement of 9, 20, and 17%, respectively. In addition, permeability of CO₂ > N₂ > H₂ > CH₄ increased by 13.2% (CO₂), 15.1% (N₂), 11% (H₂), and 4.6% (CH₄) at the same temperature. Based on that, pressure and temperature are considered as key factors that can be used to enhance the gas permeation and to control their pore shape. Also, PES membranes can be classified as a promising emerging technology for biogas upgrading with high selectivity, especially at high separation temperatures and low pressure.

当前，热处理被广泛用于将数百万吨的生物质和城市固体废物转化为能源产品。虽然沼气代表$〜$这些能量产品的50％通常由于难以从被CO ₂，N ₂等污染的复杂成分中提取CH ₄和H ₂（主要易燃化合物）而处置。最近，聚醚砜（PES）膜已用于作为一种有效且廉价的技术，其在较高压力和温度下的渗透性能仍然不确定。在此背景下，本研究旨在研究高温和高压对CO ₂ / N ₂，CO ₂ / H ₂和CO ₂ / CH _{4的影响。}PES膜的选择性性能及其在沼气升级系统中的潜在应用。实验开始于使用相转化方法制备PES膜，然后使用SEM，XRD，FTIR，TGA和通用测试机观察其形态，物理，化学，热和机械行为。连续地，进行了使用CO ₂气体的初始气体分离实验，以确定合成的PES膜可以承受的最大压力和温度，而不会受到损坏或热降解。基于初始实验的结果，CO ₂ / CH ₄，CO ₂ / N ₂和CO ₂ / CH ₄使用专门为此目的而建立的装置在高达60°C和6 bar（绝对压力）的条件下测量PES膜的选择性。此外，研究了分离温度和压力对分离机理的影响。结果表明，最低压力（1 bar）和最高温度（60°C）可以帮助实现对CO ₂ / N ₂（0.91），CO ₂ / H ₂（1.25）和CO ₂的最大选择性。/ CH ₄（3.07），分别提高了9％，20％和17％。此外，CO ₂ > N ₂ > H ₂ > CH _4的磁导率提高了13.2％（CO ₂），15.1％（N ₂），11％（H ₂）和4.6％（CH ₄）。基于此，压力和温度被认为是可用于增强气体渗透并控制其孔隙形状的关键因素。同样，PES膜可被分类为具有高选择性的沼气提纯的有前途的新兴技术，特别是在高分离温度和低压下。