Single-Step Scalable Fabrication of Zeolite MFI Hollow Fiber Membranes for Hydrocarbon Separations

Despite the high potential of zeolite MFI membranes for the separation of important hydrocarbons, their impact on industrial hydrocarbon separations has been limited by challenges in scalable fabrication methods and use of high-cost membrane supports. Here a one-step method for fabrication of highly selective and thin (<1 mu m) MFI zeolite membranes on low-cost alpha-alumina hollow fiber supports is demonstrated. This is enabled by use of a highly concentrated silicate precursor gel containing MFI nanocrystals that induces a compact membrane layer at the support surface in a single-step membrane synthesis. These one-step crystallized MFI hollow fiber membranes show excellent characteristics for butane isomer separation (n-butane permeance > 10(-7)mol m(-2)s(-1)Pa(-1)andn-butane/i-butane separation factors > 50 ), as well as for removal of natural gas liquids (butane, propane, and ethane) from methane at elevated feed pressures up to 9 bar. It is further demonstrated that the scalability of the current strategy by successful fabrication of a high-quality ten-membrane module in a single synthesis batch.