Abstract Unconventional methane resources are usually diluted in air, which prevents their use as feedstock in chemical or thermal processes. Some of them (e.g. coal mine ventilation air or diluted landfill biogas) are emitted directly to the atmosphere without harnessing, increasing the contribution of methane to global warming. Gas permeation membranes offer an alternative for the concentration of these methane resources, increasing considerably their harnessing possibilities. Microporous materials, such as carbon molecular sieve, zeolite or metal organic frameworks, have emerged as alternative to polymeric materials for the preparation of these membranes. The present work is based on simulations of the separation of methane and nitrogen mixtures, using SAPO-34 and carbon molecular sieve membranes. Mass transfer has been modelled in two scales: the membrane material (modelled using the Maxwell-Stefan multicomponent surface diffusion model) and the membrane module (based on the plug flow model). A sensitivity analysis of the influence of the main operating variables on the membrane performance has revealed that the most important ones are transmembrane pressure difference, methane feed concentration and membrane loading. It has been found that SAPO-34 membranes are more suited to concentrate methane in lean mixtures, while the carbon membrane perform better with rich mixtures. The membrane process has been scaled-up for a feed gas flow rate of 1000 m3/h n.t.p. with target methane recovery of 70% for two cases: lean (1%) and rich (50%) methane feed mixtures.

中文翻译：

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使用微孔膜浓缩非常规甲烷资源：过程评估和放大

摘要 非常规甲烷资源通常在空气中被稀释，这阻碍了它们在化学或热过程中用作原料。其中一些（例如煤矿通风空气或稀释的垃圾填埋场沼气）未经利用就直接排放到大气中，从而增加了甲烷对全球变暖的贡献。气体渗透膜为这些甲烷资源的浓缩提供了一种替代方案，大大增加了它们的利用可能性。微孔材料，如碳分子筛、沸石或金属有机骨架，已成为制备这些膜的聚合物材料的替代品。目前的工作基于使用 SAPO-34 和碳分子筛膜分离甲烷和氮气混合物的模拟。传质已在两个尺度上建模：膜材料（使用 Maxwell-Stefan 多组分表面扩散模型建模）和膜组件（基于活塞流模型）。主要操作变量对膜性能影响的敏感性分析表明，最重要的是跨膜压差、甲烷进料浓度和膜负载。已经发现 SAPO-34 膜更适合浓缩贫混合物中的甲烷，而碳膜在富混合物中表现更好。膜工艺已按比例放大，进料气流速为 1000 m3/h ntp，目标甲烷回收率在两种情况下为 70%：贫 (1%) 和富 (50%) 甲烷进料混合物。