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.
