(355b) High Performance Carbon Molecular Sieves (CMS) Hollow Fiber Membranes for Natural Gas Separation

  Nitesh Bhuwania, William J. Koros

Nitesh.Bhuwania@chbe.gatech.edu

                                                                                                                          bill.koros@chbe.gatech.edu

       School of Chemical and Biomolecular Engineering

       Georgia Institute of Technology, Atlanta, GA

CMS membranes show the enhanced separation capability for natural gas purification (processing of CO₂ from CH₄ stream). For industrial application, it is important to achieve this high performance in hollow fiber membrane configuration. Previous studies in CMS hollow fibers have shown the ability to achieve the good separation efficiency (i.e. selectivity) for CO₂/CH₄ but with a drop in transport flux in comparison to polymer precursor fibers. This is caused by the densification of porous morphology in CMS fibers, termed as”sub-structure collapse”.

CMS membranes are formed by heating the polymer precursors at higher temperatures above its decomposition point. The phenomenon of sub-structure collapse occurs during the thermal transition of polymer, which begins at its glass transition temperature (T_g). Therefore in our study, we look at stabilizing the precursors before they undergo the thermal decomposition.   Commercial available “Matrimid^®” and custom-synthesized 6FDA-BPDA/DAM polyimides were used as the precursor platform for our research.

The impact of pre-pyrolysis stabilization on fiber morphology and separation performance for final CMS fiber membrane is significant. Our technique not only show attractive separation performance but also overcomes some key challenges during the processing of CMS membranes. We will go in detail of our method during the talk.