Separation of <scp>C₂–C₄</scp> hydrocarbons from methane by zeolite <scp>MFI</scp> hollow fiber membranes fabricated from <scp>2D</scp> nanosheets

Abstract

Abstract Separation of higher hydrocarbons from methane is an important and energy‐intensive operation in natural gas processing. We present a detailed investigation of thin and oriented MFI zeolite membranes fabricated from 2D MFI nanosheets on inexpensive α‐alumina hollow fiber supports, particularly for separation of n ‐butane, propane, and ethane (“natural gas liquids”) from methane. These membranes display high permeances and selectivities for C 2 –C 4 hydrocarbons over methane, driven primarily by stronger adsorption of C 2 –C 4 hydrocarbons. We study the separation characteristics under unary, binary, ternary, and quaternary mixture conditions at 298 K and 100–900 kPa feed pressures. The membranes are highly effective in quaternary mixture separation at elevated feed pressures, for example allowing n ‐butane/methane separation factors of 170–280 and n ‐butane permeances of 710–2,700 GPU over the feed pressure range. We parametrize and apply multicomponent Maxwell–Stefan transport equations to predict the main trends in separation behavior over a range of operating conditions.