PDMS coated asymmetric PES membrane for natural gas sweetening: Effect of preparation and operating parameters on performance

Abstract

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.

Improved gas transport properties of polyurethane–urea membranes through incorporating a cadmium‐based metal organic framework

“…The CO 2 permeability increased by increasing the feed pressure; however, the permeability of other gases decreased. The rubbery nature of the PUU and its polar ethereal groups are responsible for the enhancement of the CO 2 permeability with pressure . The enhancement is greater for the PUU–HDC–2.5 due to the high affinity of the particles toward CO 2 .…”

“…The rubbery nature of the PUU and its polar ethereal groups are responsible for the enhancement of the CO 2 permeability with pressure. 72 The enhancement is greater for the PUU-HDC-2.5 due to the high affinity of the particles toward CO 2 . The tendency of particles to interact more with CO 2 rather than other gases was shown in the recent publication.…”

Synergy of CO 2 removal and light hydrocarbon recovery from oil-field associated gas by dual-membrane process

“…The separation efficiency of the SMM processes ( Fig. 1b) will also be reduced because of the low LHC/CO 2 selectivity of vapor membrane (Saedi et al, 2014;Scholes et al, 2012). As a result, the rectification operating cost has to be raised to maintain the quality of the LHC product (O'Donoughue et al, 2014).…”

Experimental evaluation and theoretical prediction of CO2 & CH4 permeation in PSF/PDMS composite membrane under the influence of membrane swelling

“…[9] Many composite polymeric membranes had been reported in the literature for gas separation applications. Saedi et al [14] developed a PDMS/PES composite membrane and reported the CO 2 /CH 4 real selectivity of 26.54. Similarly, Madaeni et al [11] developed a PDMS/PES (polyethersulphone) composite membrane with dip coating and manual film casting, and tested the developed membrane for CO 2 /N 2 and CO 2 /CH 4 separation.…”