PBI-HFA Hollow Fiber Membrane for Selective Hydrogen Separation

We demonstrated for the development of PBI-HFA based asymmetric hollow fiber membrane for hydrogen separation. High molecular weight PBI-HFA was synthesized in-house by a solution polycondensation method [1]. Hollow fiber membranes were fabricated by conventional dry-jet wet spinning technique. Defect free asymmetric PBI-HFA hollow fiber membranes were successfully produced, which influenced of PBI-HFA concentration and LiCl as shown in Fig. 1. The effect of bore fluid chemistry was found to have a significant effect on the morphology as well as gas performance of the hollow fiber membranes. Development of PBI-HFA hollow fiber membranes with improved gas permeation properties their known excellent thermal and chemical properties depicts their potential for gas separation applications at harsh environment. As shown in Fig. 2, PBI-HFA hollow fiber showed good gas flux and selectivities for industrially important gas pairs such as H2/CO, H2/N2 with the ideal selectivities of 35.7 and 43.4, respectively, while the permeation fluxes of H2, N2, CO2 and CO were at 664, 15.3, 263.37 and 18.6 GPU at 1bar as given in Table. 1. Mixed gas results as given in Table. 2 discussed above indicate that PBI-HFA hollow fiber is an excellent H2 selective membrane material for syngas separations. This improvement in gas selectivities was attributed to their increased closer chain packing by high solubility. Pressure P (H2) a P(N2) a P(CO2) a P(CO) a 1bar 664 15.3 263.37 18.6 43.4 2.52 35.70 17.21 2bar 1219 31.02 471.26 35.82 39.3 2.59 34.03 15.19 3bar 1783 46.61 691.78 54.13 38.25 2.58 32.94 14.84 4bar 2353 63.58 978.76 71.83 37.13 2.4 32.76 15.44 a Expressed as permeance in GPU (1 GPU = 1´10-6cm3(STP) cm-2s-1 cmHg-1). Table 1. Gas separation performance of PDMS coated PBI hollow fiber at normalized temperature. (H2)% (N2)% (CO2)% (CO)% Mixture gas composition 51.53 21.2 7.63 17.86 1 bar 89.6 0 3.05 0.33