用于脱碳提纯氢气的CO2优先渗透分离膜研究

CO2 removal is a key process for hydrogen production that benefits the clean and efficient utilization of fossil fuel. Membrane separation technology based on CO2 permselective membranes is an effective and environment-friendly method for CO2 removal in hydrogen production processes. However, the undesirable performance of current membranes for CO2/H2 separation is difficult to meet the demands. According to the intensive studies of transport characteristics of CO2 and H2 molecule in membranes, the key scientific problem to improve membrane performance for CO2/H2 separation has been clarified. The key scientific problem is how to construct pore channels in the membrane that could make CO2 permeate prior to H2 based on monomolecular surface diffusion mechanism. The pore channels contain well-dispersed CO2-philic functional groups and has the diameter of 6.60-8.67Å/9.49Å. Accordingly, high-performance mixed matrix membranes (MMMs) for CO2/H2 separation will be fabricated by using highly compatible polymers and metal organic frameworks (MOFs) as the continuous phase and dispersed phase, respectively. The membranes developed in this project will meet the demands of CO2 removal in hydrogen production processes, which will support the clean and efficient utilization of fossil fuel. Moreover, more efficient theory and method will be proposed to achieve the preferential permeation of larger molecule through the membrane which is a common challenge in membrane separation, promoting the development of membrane science and technology.

脱碳提纯氢气是实现化石能源高效洁净利用的制氢过程的重要环节，采用CO2优先渗透分离膜（CO2/H2分离膜）可望更高效环保地脱碳提纯氢气。但目前CO2/H2分离膜的性能难以满足应用要求。我们基于对CO2和H2在膜中传递特性的深入分析，阐明提高CO2/H2分离膜性能需解决的关键科学问题是：如何在膜中构筑合理分布亲和CO2功能团且直径为6.60-8.67Å/9.49Å的孔道，以实现CO2优先H2进入膜且主要以单分子层表面扩散机制传递。围绕该科学问题，提出通过设计合成高度相容的聚合物和金属有机框分别作为混合基质膜的连续相和分散相制备高性能CO2/H2分离膜。本项目将开发出满足脱碳提纯氢气实用要求的分离膜，为化石能源高效洁净利用提供基础。同时本项目将为解决“如何强化大分子优先小分子透过膜”这一膜分离领域的普遍性难题提供更清晰的理论依据和更有效的技术手段，从而促进膜科学技术的发展。

本项目针对化石能源高效洁净利用的重大需求，以研制出性能满足脱碳提纯氢气要求的CO2优先渗透CO2/H2分离膜为目标，围绕“如何在膜中构筑合理分布亲和CO2功能基团且直径为6.60-9.49Å 的孔道，以实现CO2优先H2进入膜内且主要以单分子层表面扩散机制传递”这一关键科学问题，按照研究计划设计合成了高度相容的“强亲和CO2聚合物”和“低聚物诱导MOF”类多孔材料，分别作为混合基质膜的连续相和分散相，制备出高性能CO2/H2分离膜。如，所制AMT/PSf混合基质复合膜，在原料气压力为3.0 MPa以内，其CO2渗透速率为800 GPU，是任务书指标（100 GPU）的8倍；CO2/H2分离因子为75，是任务书指标低限（30）的2.5倍、高限（50）的1.5倍。这样的性能处于目前国际领先水平。.此外，我们还创制了MMPs和MPFs这样的聚合物框架材料，其突破了一般MOFs的局限性，将聚合物分子作为多孔材料的重要构件，进而首次实现了不必制备混合基质膜而直接用纯多孔材料制备超薄大面积膜，为气体分离膜制备技术的发展开辟了一个宽阔的新领域。我们还进一步研究了CO2/H2分离膜过程的计算模型和计算方法，获得了膜性能对过程分离效果影响规律的新认识，从而拓展了脱碳提纯氢气过程对膜的选择范围。.在本项目资助下，项目组在Nature Materials、Angewandte Chemie-International Edition及AIChE Jounral等知名刊物上发表论文47篇，其中36篇被SCI收录；申请国家发明专利13项，其中已有2项获得授权。.本项目研究成果促进了膜科学技术的发展，也为化石能源高效洁净利用提供了重要基础。