CO2 capture technologies: current status and new directions using supported ionic liquid phase (SILP) absorbers

Current state-of-the-art techniques for CO₂ capture are presented and discussed. Post-combustion capture of CO₂ by absorption is the technology most easily retrofitted to existing installations, but at present this is not economically viable to install and run. Using ionic liquids instead of aqueous amine solutions overcomes the major thermodynamic issues. By applying SILP technology further advances, in terms of ease of handling and sorption dynamics, are obtained. Initial experimental studies showed that ionic liquids such as tetrahexylammonium prolinate, [N6666][Pro], provide a good candidate for CO₂ absorption using SILP technology. Thus a solid SILP absorber comprised of 40 wt% [N6666][Pro] loaded on precalcined silica quantitatively takes up about 1.2 mole CO₂ per mole of ionic liquid in consecutive absorption-desorption cycles in a flow-experiment performed with 0.09 bar of CO₂ (9% CO₂ in He).