CO2 stripping from ionic liquid at elevated pressures in gas-liquid membrane contactor

Abstract

In this study, the gas-liquid membrane contactor was considered for regeneration of the roomtemperature ionic liquids (RTIL) that can be used as physical solvents for carbon dioxide capture process at elevated pressures. Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) was selected as a membrane material due to its high mass transport characteristics and good mechanical properties. Nine different RTILs, such asand [P66614][Phos], were used to evaluate the solvent-membrane compatibility. The long-term sorption tests (40+ days) revealed that the solvent-membrane interaction is mainly determined by the liquid surface tension regardless of viscosity and molecular size of RTILs. For instance, [Emim][BF4] and [Emim][DCA], having the surface tension of 60.3 and 54.0 mN/m, demonstrated a very low affinity to the bulk material of PTMSP (sorption as low as 0.02 g/g; no swelling); while for the next ionic liquid [Bmim][BF4] with surface tension of 44.4 mN/m, the sorption and swelling of PTMSP was 0.79 g/g and 21%, respectively. The long-term RTIL permeation test (p=40 bar, T=50°С, t>400 hours) confirmed that there is no hydrodynamic flow through PTMSP for [Emim][DCA] and [Emim][BF4]. The concept of CO2 stripping from RTIL with the membrane contactor by the pressure (p=40 bar) and temperature (T=20°С) swing was proofed by using PTMSP membrane and [Emim][BF4]. The overall mass transfer coefficient value was equal to(1.6-3.8)•10 -3 cm/s with respect to liquid flow rate. By using the resistance-in-series model, it was shown that the membrane resistance contribution to the gas transfer was estimated to be approximately 8%.

Surface Modified Polysulfone Hollow Fiber Membranes for Ethane/Ethylene Separation Using Gas-Liquid Membrane Contactors with Ionic Liquid-Based Absorbent

“…Therefore, the data on sorption and swelling indicate that PSf is resistant towards the chosen ILs. The same observation was made in our work on another membrane material-PTMSP [56]. Table 5 provides the data on contact angle values of ionic liquids for the unmodified and modified membranes.…”

Ionic liquids combined with membrane separation processes: A review

“…Additionally, the nonporous composite membrane with thin dense top layer also provides an opportunity to eliminate the effect of pore wetting. For example, Bazhenov et al [357] designed a gas-liquid membrane contactor to capture CO2. This dense flat-sheet membrane contactor was composed by [1-(trimethylsilyl)-1-propyne] and nine different RTILs.…”

State-of-the-Art Organic- and Inorganic-Based Hollow Fiber Membranes in Liquid and Gas Applications: Looking Back and Beyond

“…Membrane contactors have major applications in acid gas (e.g., CO 2 , SO 2 , and H 2 S) removal [ 585 , 586 , 592 , 593 , 594 , 595 , 596 , 597 , 598 , 599 , 600 , 601 , 602 ]. The separation performance of membrane contactors mainly relies on the selective absorption of absorbents.…”