Permeation through CO₂selective glassy polymeric membranes in the presence of hydrogen sulfide

Abstract

Minor components present in feed gas streams can have a significant influence on the separation performance of polymeric membranes. Hydrogen sulfide is present in many of the processes where CO 2 capture is possible and can therefore undergo competitive sorption with CO 2 for transport through the membrane, as well as influence the membrane morphology inducing plasticization. This study investigates the change in CO 2 permeability and CO 2 /N 2 selectivity of two glassy polymeric membranes; polysulfone and 6FDA-TMPDA, when 500 ppm H 2 S is present in the gas mixture. The outcomes of this study reveal that H 2 S in trace amounts has a strong influence on the separation performance of both membranes. For both membranes, a plasticization partial pressure $0.5-0.6 kPa H 2 S is observed. H 2 S competitive sorption is also observed and is modeled by competitive dual-sorption theory. Results suggest that mixed gas permeation influences the amount of each gas immobilized within the Langmuir voids in addition to the expected competitive sorption effects.

High performance ZIF-8/PBI nano-composite membranes for high temperature hydrogen separation consisting of carbon monoxide and water vapor

“…As a consequence, besides investigating the temperature-dependent separation performance, we will examine the effects of impurities such as CO and H 2 O vapor on the newly developed membrane. So far, there are many reports on the effects of CO [55,56], water [55,57], H 2 S [58], NO [56], ethane [59] and toluene [60] on CO 2 /CH 4 and CO 2 /N 2 separations, and CO on CO 2 /H 2 separation [61], but almost no studies were focused on the influences of CO and H 2 O vapor to high temperature H 2 /CO 2 separation. Therefore, advanced characterizations and measurements will be carried out to study membrane morphology, permeation mechanism, and performance evolution at high temperatures in the presence of impurities.…”

Effects of Minor SO2 on the Transport Properties of Fixed Carrier Membranes for CO2 Capture

“…Swelling of the membrane induced by minor impurity gas was also reported in the literature. 29 As shown in Figure 3b, at a given feed pressure, the N 2 permeance decreases when SO 2 is present in the feed gas, which is caused by the "salting out" effect. 48,49 However, the N 2 permeance tested with 5000 ppm of SO 2 /CO 2 /N 2 mixed gas is higher than that tested with 35 ppm of SO 2 /CO 2 /N 2 mixed gas at high feed pressure, which is attributed to the plasticization.…”

“…This is attributed to the competitive sorption and competitive reaction caused by SO 2 in the membrane. On one hand, the competitive sorption between SO 2 and CO 2 would reduce the solubility of CO 2 in the membrane, 29 which means the increase in H A and decrease in R as described in eq 16. On the other hand, the competitive reaction caused by SO 2 would also reduce the CO 2 permeance as described by eq 16 in which the increase in x leads to the decrease in R.…”

Upgrading of raw biogas using membranes based on the ultrapermeable polymer of intrinsic microporosity PIM-TMN-Trip

“…S4 in the SI). Despite the concentration of H2S in the biogas being ~430 ppm, no H2S-induced swelling was observed, even though some common membranes are susceptible to this effect at comparable H2S concentration, and no reduction of permeability of other gases in the mixture was observed due to competitive sorption at low partial pressures of H2S [36][37][38]. This can be attributed to the high free volume and the resulting high sorption capacity of the membrane.…”