Dual-Membrane Module and Its Optimal Flow Pattern for H2/CO2 Separation

A dual-membrane module is able to provide higher separation performance for H2/CO2 gas mixtures compared to conventional single-membrane modules. In this work, the flow patterns of dual-membrane modules are studied, and the results indicate that the co­(H2):counter­(CO2) flow pattern is the optimal flow pattern for H2 recovery. The co­(H2):counter­(CO2) flow pattern employs cocurrent (permeate flow parallel to bulk flow) to the H2-selective membrane and counter-current (permeate flow reverse to bulk flow) to the CO2-selective membrane; the flow pattern reduces the permeation flux of CO2 in the H2-selective membrane, resulting in a higher H2 separation factor. The evaluations show that the H2 product purity could be raised by 35% (from 62 mol % to 84 mol %) compared to conventional membrane modules. The results indicate that enhancing the membrane separation performance through flow pattern is a practical and effective method for process engineering.