From Polymer Screening to Process Validation: Membrane Hydrogen Recovery from Biomass-Derived Syngas

Hydrogen recovery from biomass-derived synthesis gas requires membrane materials that combine adequate productivity with stable multicomponent selectivity and can be translated into practical hollow-fiber modules. In this work, polysulfone (PSF), polyphenylene oxide (PPO), and polyetherimide (PEI) were systematically evaluated for separation of a post-water-gas-shift H2/CO2/CH4/CO mixture. Pure- and mixed-gas transport was first characterized using dense films, followed by mixed-gas testing of untreated asymmetric hollow fibers. PPO provided the highest hydrogen permeance (230 GPU) but low H2/CO2 selectivity (1.21), whereas PEI combined a hydrogen permeance of 52 GPU with H2/CO2, H2/CH4, and H2/CO selectivities of 4.52, 167.7, and 173.3, respectively. PEI was therefore selected for process optimization. Two-stage recycle configurations were evaluated using a multicomponent hollow-fiber model. The optimized retentate-recycle configuration predicted 90.03 mol.% H2 purity and 90.85% hydrogen recovery. Laboratory validation reproduced the predicted purity–recovery trade-off and identified an overall stage cut near 0.5 as the relevant operating region, with experimental purity and recovery both approaching 90%. The results demonstrate that experimentally determined mixed-gas hollow-fiber transport properties combined with process-level optimization provide a practical route for designing polymeric membrane systems for renewable hydrogen recovery.