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Defect‐free polyamide‐imide (Torlon®) hollow fiber membranes were fabricated to investigate the potential for polymer‐based organic solvent reverse osmosis (OSRO) separations. The quality of the membranes was assessed by gas permeation, and the membranes were found to be defect‐free. Low molecular weight cut‐offs of ~180 g/mol were obtained using a complex mixture of aromatic hydrocarbons relevant to refinery separations. We demonstrate bulk OSRO‐type separations of 80/20 (mol%) mixtures of toluene and 1,3,5‐triisopropylbenzene (TIPB, 204 g/mol). At an upstream pressure of 80–90 bar, we find that the permeate concentration was approximately 98.5–99.0 mol% toluene and that the TIPB rejection coefficient was approximately 90% in the permeate. We observed low solvent permeances of 0.01 L/m2 hr bar, which can be attributed to the low OSRO driving forces and the low permeability of Torlon®. The membranes were found to provide stable performance up to pressures of 95 bar and temperatures of 60°C.

Pipeline natural gas is the primary fuel of choice for distributed fuel cell-based applications due to its well-developed infrastructure. The concentration of sulfur in odorized pipeline natural gas is about 30 ppm, with the acceptable level being <1 ppm for catalyst stability in such applications. Packed bed technology for desulfurization suffers from several disadvantages including high pressure drop and slow regeneration rates that require large unit sizes. This paper describes a new sorption platform utilizing hollow fibers with polymer “binder”, impregnated with high loadings of sulfur selective zeolite sorbent “fillers”. Temperature Swing Adsorption (TSA) can be utilized to thermally cycle the sorbents between sorption and regeneration cycles. A simplified flow pattern minimizes pressure drop, while a porous core morphology maximizes sorption efficiencies and high surface area to volume ratio structures can enable smaller bed sizes. This new technology represents a fusion of membrane science and adsorption technology.

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