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PDMS coated asymmetric PES membrane for natural gas sweetening: Effect of preparation and operating parameters on performance
Author(s) -
Saedi Shahab,
Madaeni Sayed S.,
Shamsabadi Ahmad Arabi
Publication year - 2014
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.21947
Subject(s) - sweetening , natural gas , materials science , membrane , chemical engineering , chemistry , sweetening agents , engineering , organic chemistry , biochemistry , food science
The present study is an attempt to investigate the effects of preparation and operation parameters on ideal and real selectivity of polydimethylsiloxane (PDMS) coated asymmetric polyethersulfone (PES) membranes for natural gas sweetening. Scanning electron microscopy (SEM) was used to study the effect of PES concentration and solvent type on membrane morphology. The effects of operating parameters on the performance of membranes were investigated by using binary CO 2 /CH 4 , H 2 S/CH 4 and ternary H 2 S/CO 2 /CH 4 gas mixtures. Higher concentrations of PES and a higher sequential coating number increase CO 2 /CH 4 selectivity and decrease CO 2 permeance. As a notable and interesting result, the membrane exhibits rubbery PDMS behaviour for H 2 S containing feeds and displays a glassy PES membrane for CO 2 /CH 4 mixed gas. An increase in the feed pressure decreases CO 2 and CH 4 permeance and increases CO 2 /CH 4 selectivity for CO 2 /CH 4 feed. For H 2 S/CH 4 and H 2 S/CO 2 /CH 4 mixed gas, enhancing the feed pressure results in higher CH 4 and lower CO 2 and H 2 S permeance and a declined CO 2 /CH 4 and H 2 S/CH 4 selectivity. Increasing temperature in binary CO 2 /CH 4 enhances CO 2 and CH 4 permeance and decreases CO 2 /CH 4 selectivity. Increasing the temperature increases CH 4 permeance and decreases H 2 S permeance for binary H 2 S/CH 4 mixture. For ternary mixture, increasing the temperature leads to a higher permeance for CO 2 and H 2 S and a lower CH 4 permeance. For binary CO 2 /CH 4 , a higher CO 2 concentration increases the membrane gas permeance and decreases CO 2 /CH 4 selectivity. Increasing the H 2 S concentration in the feed results in a reduction in gas pressure normalised flux of gases in ternary gas feed because of an increase in Flory–Huggins interaction parameter.