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Hydrogen separation from gas mixtures using polymeric membranes

Abdollahi, Yaser | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46247 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Mousavi, Abbas; Bastani, Darioush; Sadatnia, Behrooz
  7. Abstract:
  8. Because of higher hydrogen demand in recent years, study of hydrogen separation from gas mixtures is highly regarded. Because of some parameters such as high surface to volume ratio and ability to withstanding high pressure, polymeric hollow fiber membranes have a good potential of hydrogen recovery. So in this study, fabrication of single-layer and dual-layer hollow fiber membranes have been investigated. Selective polymer that used in both single and dual layer membranes is polyethersulfone. Membranes were fabricated by dry-wet phase inversion method and effects of extrusion rates and their ratio, composition and temperature of polymer solution, composition of bore fluid, coating and air gap on structure and membrane properties have been studied. Analysis methods are gas permeation test and studying of membranes morphology by SEM. Studies showed that reaching desirable properties requires a ratio of dope extrusion rate to bore fluid extrusion of 3 to 1 cm3.min-1, using water and solvent mixture in bore fluid, and coated membranes. Optimum dope composition for reaching desirable properties of single-layer hollow fiber membranes is 35 wt % PES, 41.25 wt % NMP, 10 wt % Ethanol, and 13.75 wt % THF. Recommended temperature for extrusion of dope solution is 60℃. In this case, hydrogen permeance is 35.1 GPU and H2/CH4 selectivity is 66.2 (93 % of polyethersulfone dense film selectivity). PES/PSF dual-layer membranes were fabricated by considering effective parameters and delamination-free structure. Best membrane achieved by Using of 35 wt % PES, 55 wt % NMP, 10 wt % Ethanol in outer layer dope solution and 25 wt % PSF, 65 wt % NMP, 10 wt % Ethanol in inner layer dope solution. In this case hydrogen permeance and H2/CH4 selectivity were 39.9 GPU and 66.2 respectively
  9. Keywords:
  10. Hydrogen Separation ; Hollow Fiber Membrane ; Permeability ; Selectivity ; Phase Inversion

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