Preliminary Studies of CO₂ Removal from Precombustion Syngas through Pressure Swing Membrane Absorption Process with Ionic Liquid as Absorbent

Abstract

Using 1-butyl-3-methylimidazolium dicyanamide ([bmim]­[DCA]) as the absorbent and either hydrophobized porous ceramic tubule or hydrophobized polyether ether ketone (PEEK)-based porous hollow fiber membranes, we have carried out preliminary studies for CO2 removal from simulated precombustion syngas by a pressure swing membrane absorption process. We have used He as a surrogate for H2 (40% CO2 rest He) up to a temperature of 100 °C and a pressure of 250 psig. A novel 5-valve system was designed to improve product quality. The optimal duration for the key absorption step was determined, and the influence of helium-rich product withdrawal time was investigated. Temperature increase will degrade product quality, so adding polyamidoamine dendrimer of generation 0 to [bmim]­[DCA] will mitigate the temperature effect, and 15 wt % dendrimer in [bmim]­[DCA] showed the best performance. Feed pressure increase will degrade helium product quality, while it is beneficial for CO2 product quality, since more CO2 will be absorbed with a higher feed pressure. When feed gas pressure was 250 psig at CO2 side ∼88.2% CO2-enriched gas product was produced. Using a simulated two-stage large PEEK module system, with a 14.0% CO2 balance helium gas mixture, helium product with CO2 concentration as low as 4.2–5.8% could be achieved at different temperatures. A brief analysis has been provided to explain why a PEEK membrane module shows much better performance than the ceramic tubule.

Preparation, characterization and laboratory-scale application of modified hydrophobic aluminum oxide hollow fiber membrane for CO2 capture using H2O as low-cost absorbent

“…More recently, [26] and yttrium-stabilized zirconia (YSZ) [27] were applied with success as a practicable alternative hollow fiber in the advanced field of "water desalination" via membrane distillation process. In this light, Jie et al [34] investigated silane-coated hydrophobic porous ceramic tubule in comparison with hydrophobized polyether ether ketone (PEEK)-based porous hollow fiber membranes using 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]) as pure ionic liquid absorbent for CO 2 removal from simulated precombustion syngas by a pressure swing membrane absorption (PSMAB) process, and the authors suggest that there is significant potential for future research in the area of ceramic module that show stable separation results under high temperature. In particular, Chau et al [35] suggested that the ceramic system produced poor product qualities with pure ionic liquid [bmim][DCA] due to large tube side gas volume and small gas-liquid contacting area.…”

Novel membrane contactor for CO 2 removal from flue gas by temperature swing absorption

“…In the module used here, the shell-side liquid amine thickness between the contiguous hollow fibers is considerable resulting in the not-so-sharp-a-rise in the outlet CO 2 concentration. [27,29].…”

Polyamidoamine-facilitated poly(ethylene glycol)/ionic liquid based pressure swing membrane absorption process for CO2 removal from shifted syngas

“…As a result the gas located at the furthest point from the feed gas entrance is purer in helium than at any other locations since the absorbent is CO 2 -selective. This 5-valve based PSMAB system was first proposed by Jie et al [13]. The cycle time varies between 75 to 150 s; a typical distribution of cycle time for each step in second for the 6 steps is as follows: 10; 60; 1; 3; 60; 2.…”

“…The cycle time varies between 75 to 150 s; a typical distribution of cycle time for each step in second for the 6 steps is as follows: 10; 60; 1; 3; 60; 2. Generally one small membrane module was used to study the process [13,14]. Here we have two membrane modules to increase the membrane surface area.…”

“…The operational configurations employed here have some similarities to pressure swing adsorption (PSA) processes as if we were working with adsorbents. The basic concepts of the PSMAB process have been illustrated in the following references: Jie et al [13], Jie et al [14], Chau et al [15].…”