Hydrogen separation from multicomponent gas mixtures containing CO, N ₂ and CO ₂ using Matrimid ^® asymmetric hollow fiber membranes

The application of hollow fiber membranes for the separation of industrial gas mixtures relies on the correct characterization of the permeation of the involved gaseous components through the hollow fiber membranes. Thus, this study is focused on the characterization of the permeation through Matrimid ^® hollow fiber membranes of four gas mixtures containing H ₂ (H ₂/N ₂, H ₂/CO, H ₂/CO ₂), and the quaternary gas mixture H ₂/N ₂/CO/CO ₂, working at a constant temperature of 303K and pressures up to 10bar. The main differences and similarities in the gas permeation properties of hollow fibers with respect to flat membranes, as well as in the permeation of gas mixtures with respect to pure gases, are discussed. Our results suggest that for mixtures containing H ₂ and CO ₂ hollow fiber membranes perform better than flat membranes given that a lower depression in the permeability of H ₂ has been observed. At 2.3bar feed pressure, ideal selectivity values obtained for H ₂/N ₂, H ₂/CO and H ₂/CO ₂ gas pairs were 74.4, 42.6 and 5 respectively, with a H ₂ permeance of 50.2×10 ^-8m ³(STP)m ^-2s ^-1kPa ^-1. The specific behavior observed in the permeation through hollow fiber has been explained by a combination of different phenomena such as hollow fiber membrane substructure resistance, CO ₂ induced plasticization and competitive sorption effects between the components of the gaseous mixtures.