Advanced nanostructured composite membranes for gas separations

由于先进的气体分离技术对石油化工、能源和资源部门的重要性，它对加拿大工业变得越来越重要；然而，目前的解决方案在某些应用中是有限的。这项研究将致力于开发具有定制纳米结构的先进复合膜，以实现对加拿大工业很重要但传统技术难以实现的气体分离。具体而言，本研究旨在开发具有定制纳米结构的创新复合膜，用于1)烯烃/石蜡分离（取代或补充传统的高能耗低温蒸馏），2)天然气脱氮升级，以及3)从烟气中分离二氧化碳以控制温室气体排放，这需要高膜的选择性，以使该过程在经济上可行。烯烃分离和天然气脱氮是天然气工业中最具挑战性的两个操作，而烟气分离对于碳捕获和减少污染至关重要。它们都与加拿大在石化、资源和能源行业创新技术的战略发展直接相关。**膜技术已经成为一种节能的单元操作，但目前这一代的膜还不够好，不能用于上述分离。提出通过调整膜的组成和纳米结构来提高膜的性能。在一种方法中，将适当的络合剂掺入聚合基膜中，以通过化学相互作用促进目标组分（例如烯烃）的渗透。络合剂将均匀地嵌入基础聚合物膜中，形成纳米结构的复合膜。将选择银离子和胺分子分别作为烯烃和二氧化碳的络合剂，以研究烯烃-银和二氧化碳-胺的特定相互作用。**在另一种方法中，具有由软段和刚性段组成的微双相分离微结构的嵌段共聚物将用于N2/CH4分离，这在天然气脱氮的实践中确实是一个挑战，因为其他技术（例如吸收、吸附）也不足够。对于这对气体，缺乏合适的化学促进络合剂。然而，在嵌段共聚物中，软段有助于高渗透率，而刚性段预计会对气体分子的扩散造成干扰。通过调整这两个片段可以定制它们的分子结构，也可以将与CH4或N2具有特定相互作用或分子筛分作用的添加剂加入到膜中，形成混合基质纳米复合材料，从而提高膜对N2/CH4分离的整体选择性。由于含氮量高，加拿大的许多天然气储量都是劣质的，该膜的成功开发将对该行业产生重大的经济影响。**提议的研究具有很强的原创性和创新性。基于我们在烯烃/石蜡分离方面的这种创新方法的初步成功，加拿大工业界正将其作为加拿大拥有的潜在“突破性”技术进行商业开发，这项研究将扩展到包括用于二氧化碳分离和天然气脱氮的先进膜，通过适当的纳米结构。这项工作不仅直接满足了加拿大对先进膜技术的工业需求，也将为提高知识水平和培养高素质人才做出重大贡献。

Advanced technologies for gas separation have become increasingly important to Canadian industry because of its significance to petrochemical, energy and resource sectors; however, current solutions are limited for certain applications. The proposed research will pursue development of advanced composite membranes with tailored nanostructures to effect gas separations that are important to Canadian industries but difficult to carry out with traditional technologies. Specifically, this research aims at developing innovative composite membranes with tailored nanostructures for 1) olefin/paraffin separation (to replace or complement with traditional energy-intensive low temperature distillation), 2) nitrogen removal from natural gas for upgrading, and 3) CO2 separations from flue gas for greenhouse gas emission control where a high membrane permselectivity is needed for the process to be economically feasible. Olefin separation and natural gas denitrogenation are two most challenging operations in the gas industry, while flue gas separation is important for carbon capture and pollution abatement. They are all directly related to Canada's strategic development of innovative technologies in the petrochemical, resource and energy industries.**Membrane technologies have emerged as an energy efficient unit operation, but the current generation of membranes is not good enough for the aforementioned separations. It is proposed to tailor the membrane composition and nanostructure to enhance the membrane performance. In one approach, appropriate complexing agents will be incorporated into a polymeric base membrane to facilitate the permeation of a target component (e.g., olefin) by chemical interactions. The complexing agents will be embedded uniformly in the base polymer membrane to form nanostructured composite membranes. Silver ions and amine molecules will be chosen as the complexing agents for olefin and CO2 applications, respectively, to exploit the specific olefin-silver and CO2-amine interactions.**In another approach, block copolymers with micro-biphase separated microstructures comprising of soft segments and rigid segments will be used for N2/CH4 separation, which is truly a challenge in practice for denitrogenation of natural gas as other techniques (e.g., absorption, adsorption) are also inadequate. For this pair of gases, suitable complexing agents for chemical facilitation are lacking. However, in block copolymers, the soft segments contribute to a high permeability, while the rigid segments are expected to be discretive to the diffusion of gas molecules. Their molecular structures can be tailored by adjusting the two segments, and additives that have specific interactions with or molecular sieving effect for CH4 or N2 may also be incorporated into the membrane to form a mixed matrix nanocomposite, thereby enhancing the overall membrane selectivity for N2/CH4 separation. Many natural gas reserves in Canada are of sub-quality because of high nitrogen contents, and successful development of the membrane will have a significant economic impact to the industry.**The proposed research is highly original and innovative. Based on our preliminary success with such an innovative approach for olefin/paraffin separation, which is being exploited for commercial development by Canadian industry as a Canadian-owned potential "breakthrough" technology, this research will extend to include advanced membranes for CO2 separation and natural gas denitrogenation via appropriate nanostructuring of the membranes. Not only does this work directly address Canada's industrial needs for advanced membrane technologies, it will also contribute significantly to advancing knowledge and training of highly qualified personnel.