Abstract:

Membrane carbon dioxide separation has the advantages of no phase change and low energy consumption, and has great potential in the fields of carbon capture and gas purification. Membrane separation is a separation process based on the difference in the permeation rate of components. The difference in the physical and chemical properties of the gas components is the premise of separation, and the effective identification of the difference between the components by the membrane material is the key to efficient separation. The three representative cases about separating CO₂ from fired flue gas, natural gas and synthetic gas, have significant difference from each other in mixtures' composition and operating condition. In this instance, membrane material design, including both functional groups and aggregation structures, should thoroughly consider the characteristics of the mixtures to be separated. On the one hand, gaseous molecules' difference should be fully brought into play to enhance separation performance. On the other hand, the difference in operation condition should be regarded properly to ensure high efficiency, toleration ability, and stabilized operation. In this review paper, based on the mechanism for membrane permeation and the strategic difference among mixtures to be separation, i.e., composition and operation condition, we have summarized the research progress of CO₂ separation membrane materials in recent years. In addition, a concise outlook on future research directions and challenges on CO₂ separation membranes has also been suggested.

Key words: membrane separation, carbon dioxide, flue gas, natural gas, synthetic gas, permeability, selectivity

摘要：

膜法二氧化碳分离具有无相变、低能耗等优势，在碳捕集和气体净化等领域具有极大的潜力。膜分离是一种基于组分渗透速率差异的分离过程，其中，气体组分的物化性质差异是实现分离的前提，而膜材料有效识别组分的差异则是高效分离的关键。烟道气、天然气、合成气是最典型的三种二氧化碳分离体系，组成以及操作条件都存在显著的不同。膜材料的设计，既要充分利用组分的性质差异，进行功能基团和聚集结构的针对性设计，实现高分离性能，又要充分考虑操作条件的特殊性，保证良好的分离效率、耐受性和操作稳定性。以二氧化碳分离膜的渗透传质机理为基础，结合不同体系的组成差异和操作条件差异，综述近年来二氧化碳分离膜材料的研究进展，并对未来的研究方向以及瓶颈问题进行展望。

关键词: 膜分离, 二氧化碳, 烟道气, 天然气, 合成气, 渗透性, 选择性