| Popis: |
Ethane can be a major component of natural gas, and it forms a maximum pressure azeotrope with carbon dioxide, which can hinder carbon dioxide removal if distillation is used. This paper describes a solubility selective membrane material for this separation. A crosslinked poly(ethylene oxide) [PEO] material [XLPEO] was prepared from a prepolymer solution containing 71 wt.% poly(ethylene glycol) methyl ether acrylate [PEGMEA] monomer and 29 wt.% poly(ethylene glycol) diacrylate [PEGDA] crosslinker, and it exhibits high carbon dioxide permeability and high carbon dioxide/ethane selectivity. For example, at 253 K and 10 atm total feed fugacity, the CO 2 /C 2 H 6 selectivity for a 45 mol% CO 2 and 55 mol% C 2 H 6 gas mixture is approximately 12, and the CO 2 permeability is 83 Barrers. The performance of the membrane material for breaking the CO 2 /C 2 H 6 azeotrope was simulated using a computer model. XLPEO was found to be effective in breaking the azeotrope. At a feed composition of 45 mol% CO 2 and 55 mol% C 2 H 6 , 85% ethane recovery could be achieved at an ethane purity of 78% for a single stage membrane separation operating at 253 K and 11.3 atm total pressure. Experimental sorption, pure gas diffusion and permeability, and mixed gas permeation data for CO 2 and C 2 H 6 in this polymer are presented at temperatures ranging from 253 to 308 K. |
Full Text from ScienceDirect