Effect of temperature on intrinsic permeation properties of 6FDA-Durene/1,3-phenylenediamine (mPDA) copolyimide and fabrication of its hollow fiber membranes for CO2/CH4 separation
✍ Scribed by Jian-Jun Qin; Tai-Shung Chung; Chun Cao; R.H. Vora
- Publisher
- Elsevier Science
- Year
- 2005
- Tongue
- English
- Weight
- 633 KB
- Volume
- 250
- Category
- Article
- ISSN
- 0376-7388
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✦ Synopsis
We have determined the effect of temperature on intrinsic permeation properties of 6FDA-Durene/1,3-phenylenediamine (mPDA) 50/50 copolyimide dense film and fabricated high performance hollow fiber membranes of the copolyimide for CO 2 /CH 4 separation. The hollow fiber membranes were wet-spun from a tertiary solution containing 6FDA-Durene/mPDA (PI), N-methyl-pyrrolidone (NMP) and tetrahydrofuran (THF) with a weight ratio of 20:50:30 at different shear rates within the spinneret. We observed the following facts: (1) the CO 2 /CH 4 selectivity of the copolyimide dense film decreased significantly with an increase in temperature; (2) the performance of as-spun fibers was obviously influenced by the shear rate during spinning. For uncoated fibers, permeances of CH 4 and CO 2 decreased with increasing shear rate, while selectivity of CO 2 /CH 4 sharply increased with shear rate until the shear rate reached 2169 s -1 and then the selectivity leveled off; (3) After silicone rubber coating, permeances of CH 4 and CO 2 decreased, the selectivity of CO 2 /CH 4 was recovered to the inherent selectivity of its dense film. Both the permeances and selectivity with increasing shear rate followed their same trends as that before the coating; (4) there was an optimal shear rate at which a defect-free fiber with a selectivity of CO 2 /CH 4 at 42.9 and permeance of CO 2 at 53.3 GPU could be obtained after the coating; and (5) the pressure durability of the resultant hollow fiber membranes could reach 1000 psia at room temperature.