A study of gas permeation on a polymeric membrane: permeability, diffusivity, solubility, and its performance for H2/CO2 separation

Abstract

The gas permeation on a polymeric membrane for H₂/CO₂ separation in accordance to the solution-diffusion mechanism was studied. A commercial Polyvinyl alcohol (PVA) and Polyamide (nylon-6) membrane were used for pure and mixed gas permeation experiment and  the interaction effects of the permeance gas with these polymeric membranes were observed by determining transports parameter such as permeability coefficient (P), diffusion coefficient (D), and solubility coefficient (S). Two-steps experiments were carried out:(1) pure gas permeation of H₂ and CO₂, and (2) mixed gas permeation of H₂-CO₂ (30 % H₂ - 70 %-v CO₂). The operating pressure was varied in the range from 4 to 12 bars. Membrane performance on a gas separation was represented by permeation flux (J) and its selectivity factor (α). The experiment result showed that solubility of CO₂ in PVA was greater than Nylon-6 membrane and decrease with an increasing operating pressure. Permeability and permeation flux of H₂ were higher at both two types of membrane while the selectivity of H₂/CO₂ of nylon-6 membrane was higher in compared to PVA membrane.