中文摘要：

综述了应用于低浓度煤层气分离的主要方法，包括低温精馏法、吸附分离法、膜分离法和水合物法，探讨了各种方法在不同工艺条件下的分离效果，分析了它们的优缺点。文中总结了每种方法需要解决与突破的关键性问题：低温精馏法获得的甲烷浓度高，但在处理含氧煤层气时首先要脱氧；吸附分离的关键技术在于吸附剂的选择，吸附剂决定了该方法的经济效益与难易程度；对于膜法分离，影响煤层气分离效果的主要因素在于膜材料的选择及制膜工艺；对于水合物法，寻找制备具有较高分离效率的添加剂是关键。最后指出，多种方法结合、多级分离的分离方法是未来研究发展方向。

英文摘要：

This paper reviewed the methods of methane （CH4） separation and purification from coal-bed methane （CBM）, including low-temperature distillation, adsorption, membrane separation and gas hydrate separation. By the analysis of the advantages and the disadvantages of these methods, the separation efficiencies under different technical conditions were compared and discussed. Key issues needed to be solved for each method were summarized. For the low-temperature distillation method, de-oxidation is necessarily conducted for the oxygen-containing CBM. The selection of the adsorbent is the key for the adsorption method because the adsorbent determines the economy benefit directly. As for the membrane separation, the separation is affected by the selection of the membrane materials and membrane-making technology. For the hydrated-based CH4 separation, a good additive is crucial to promote the hydrate formation and enhance the CH4 separation efficiency. Finally, the separation of multi-methods or the separation by multi-stage processes is proposed for the future development of CBM separation.