BRIGE Exploiting crystalline framework flexibility to enable energy efficient entropically selective separations

技术描述：该项目旨在设计和开发一种微孔材料，该材料可以利用依赖温度的分子筛分现象成功分离多组分气流。沸石咪唑盐框架（ZIFs）是一类微孔材料，由于广泛的有机咪唑盐连接物的可用性，其化学性质可调。由于咪唑酸连接剂围绕框架内的配位键旋转，ZIF晶体的孔具有柔性。在这个项目中要探索的一个中心假设是，ZIF孔的灵活性与温度有关，这导致了一个可调的筛孔，可以使扩散的气体物种的熵分离。在这项工作中创建的zif将集成到最先进的多孔纤维复合材料中，从而独特地实现熵分离过程。熵分离面临的主要挑战是同时保持低气压降和控制系统整体传质的晶内扩散。高多孔纤维复合材料将使晶体中的气体扩散在低气压降下控制过程，这在传统的吸附系统中是不可行的。更广泛的意义和重要性：本项目提出的工作旨在创建一个新的材料平台，使从非常规天然气来源中高效回收有价值的天然气液体（ngl）成为可能。目前的NGL回收系统是主要的能源消耗者。一个标准?每天生产约750吨液化天然气的液化天然气回收厂将消耗相当于1万户家庭供暖的能源。该项目旨在将这种能量损失减少3-5倍。这一目标将通过创造新的晶体材料来实现，这种材料可以从原始天然气分子中“筛”出NGL分子。物理筛分过程依赖于通过新型晶体材料创造微观途径——在这些微观途径中创造和理解NGL分子运动是这个项目的主要推动力。为了使所提出的节能NGL回收系统得到广泛采用，这种新型晶体材料将被集成到合成纤维设备中，这非常适合大规模生产。这些基于纤维的ngl回收装置是该项目的第二个重点，其灵感来自于工业合成纺织纤维的生产过程。这些基于纤维的ngl回收设备的大规模生产可能会带来国内“先进”的制造业就业机会，并为美国在ngl节能回收领域提供领先优势。这里建立的基本科学和技术见解将指导未来节能气体分离和净化工艺的设计，包括从稀释源回收天然气，化学生产和氢气生产。该项目的主要目标是向年轻女性和代表性不足的少数群体介绍STEM领域，以增加加入这些领域的倾向。PI将通过在亚特兰大市内的初中和高中开展外展活动，以及利用佐治亚理工学院现有的项目来实现这一目标。bridge奖将允许PI实施旨在实现这些目标的教育外展计划。π吗?i)通过在亚特兰大市中心的中学和高中进行课堂演示和讲座，以及积极参与佐治亚理工学院(Georgia Tech？ii)利用bridge对女性和少数族裔研究助理的支持；iii)利用佐治亚理工学院现有的项目，在实验室内外为女性和少数族裔提供指导、指导和专业发展。PI将定期评估他的推广工作是否成功，并根据老师、学生和研究助理的反馈调整他的计划。这项研究是由工程教育和中心部的工程项目扩大参与计划的一部分，即工程项目扩大参与研究启动基金资助的。

Technical Description:This project seeks to design and develop a microporous material that can successfully fractionate multi-component gas streams using a temperature-dependent molecular sieving phenomenon. Zeolitic imidazolate frameworks (ZIFs) are a class of microporous material that are chemically tunable due to the availability of a wide spectrum of organic imidazolate linkers. The pores of ZIF crystals are flexible as a result of imidazolate linker rotation around coordination bonds within the framework. A central hypothesis to be explored in this project is that the ZIF pore flexibility is temperature-dependent, which results in a tunable sieving aperture that can enable an entropic separation of diffusing gas species. The ZIFs created in this work will be integrated into state-of-the-art porous fiber composites that uniquely enable the entropic separation process. A primary challenge facing entropic separations is simultaneously maintaining low gas pressure drop and intracrystalline diffusion controlling the overall mass transfer in the system. The highly porous fiber composites will allow gas diffusion in the crystal to control the process at low gas pressure drops, which is not feasible in traditional adsorption systems.Broader Signficance and Importance:The work proposed in this project aims to create a new platform for materials that enable energy efficient recovery of valuable natural gas liquids (NGLs) from non-conventional natural gas sources. The current NGL recovery systems are major energy consumers?a ?standard? NGL recovery plant that produces approximately 750 tons of NGLs per day will consume energy equivalent to the heating of 10,000 homes. This project aims to reduce this energy loss by a factor of 3-5. This goal will be achieved by creating novel crystalline materials that physically "sieve" the NGL molecules from raw natural gas molecules. The physical sieving process relies on the creation of microscopic pathways through the novel crystalline materials--creation and understanding of NGL molecular movement in these microscopic pathways is a major thrust of this project. To enable wide-spread adoption of the proposed energy-efficient NGL recovery system, the novel crystalline materials will be integrated into synthetic fiber-based devices, which are ideally suited for mass manufacturing. Creation of these fiber-based NGL-recovery devices--a second major focus of this project--is inspired by industrial synthetic textile fiber production processes. Large-scale production of these fiber-based NGL-recovery devices could potentially lead to domestic "advanced" manufacturing jobs and provide the USA with a head start in the field of energy-efficient recovery of NGLs. The fundamental scientific and technological insights established here will guide the design of future energy efficient gas separation and purification processes, including natural gas recovery from dilute sources, chemical production, and hydrogen production. Broadening Participation of Underrepresented Groups in Engineering A primary goal of this project is to introduce young women and under-represented minorities to STEM fields in an effort to increase inclination to join these fields. The PI will achieve this goal through a combination of outreach at local inner city middle and high schools in Atlanta, and by leveraging existing programs at Georgia Tech. The BRIGE award will allow the PI to implement his educational outreach plans which aim to achieve these goals. The PI?s comprehensive plan for outreach and retention of women and under-represented minorities has three primary facets: i) Outreach through in-class demonstrations and lectures at inner city Atlanta middle and high schools and active participation in Georgia Tech?s Summer Engineering Institute, ii) use BRIGE support for female and under-represented minority research assistants, and iii) leveraging existing programs at Georgia Tech to engage in mentoring, guidance and professional development of female and under-represented minorities both in and out of the laboratory. The PI will periodically assess the success of his outreach efforts and adjust his program according to feedback from teachers, students, and research assistants.This research has been funded through the Broadening Participation Research Initiation Grants in Engineering solicitation, which is part of the Broadening Participation in Engineering Program of the Engineering Education and Centers Division.