Thin-film composite membrane contactors for desorption of CO2 from Monoethanolamine at elevated temperatures

Membrane gas solvent contactors are a hybrid approach that shows potential to be more efficient for carbon dioxide capture than traditional packed columns. Here, three non-porous composite membrane contactors are trialed for desorption of CO2 from loaded Monoethanolamine (MEA) at temperatures 70 °C and above. These are non-porous poly (1-trimethylsilyl-1-propyne) (PTMSP), Polymer of Intrinsic Microporosity (PIM-1) and Teflon AF1600, all on a porous PP support. The CO2 regeneration flux was shown to increase with temperature because of increasing driving force across the membrane. Similarly, the CO2 flux increased with solvent Reynolds number because of increasing turbulence in the solvent boundary layer. The overall mass transfer coefficient for the three membrane contactors were calculated and demonstrated that desorption was a mass transfer limiting process, with over 90% of the resistance corresponding to the solvent boundary layer. The water vapor fluxes through the non-porous membrane contactors were also measured and highlighted that water permeation was greater than CO2 for all three membrane contactor systems.