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

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