The separation characteristics and dynamics of hydrogen mixture produced from natural gas reformer were studied on methyltriethoxysilane (MTES) templating silica membrane. The permeation and separation of CO pure gas, H 2 /CO (50/50, vol.%) binary mixture and H 2 /CH 4 /CO/CO 2 (69/3/2/26, vol.%) quaternary mixture were investigated both experimentally and theoretically. Since the permeance of pure CO on the MTES membrane was very low (CO ≈ 4.79-6.46 × 10 -11 mol m -2 s -1 Pa -1 ), comparatively high hydrogen selectivity could be obtained from the H 2 /CO mixture (separation factor = 93-110). This implies that CO, which should be eliminated prior to use in fuel cells, can be separated from hydrogen mixtures using MTES membranes. The permeance of the H 2 quaternary mixture on the MTES membrane was 2.07-3.37 × 10 -9 mol m -2 s -1 Pa -1 and the separation factor of H 2 /(CO + CH 4 + CO 2 ) was 6-24 at 323-473 K. Since the permeation flux in the MTES membrane was affected by both molecular sieving and surface diffusion, high H 2 selectivity could be obtained at elevated temperatures. The transient permeation/separation behaviours of hydrogen multi-component systems on the MTES membrane were predicted by the Generalized Maxwell-Stefan model incorporating the dusty gas model and Langmuir isotherm model.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physical and Theoretical Chemistry
- Filtration and Separation