Integrated carbon capture and utilization based on bifunctional ionic liquids to save energy and emissions

Abstract

The combination of CO2 capture and conversion (CCU) to produce value-added chemicals is proposed as strategy to mitigate environmental impacts and resolve the cost for CO2 conditioning, transport and storage. Although there are several CCU pathways in the literature, there are not large-scale designs of CCU processes based on ionic liquids (ILs). This work attempts to take advantage of the reported bifunctionality of ILs, as CO2 chemical absorbents and CO2 conversion catalysts, for designing new valuable CCU systems using well-stated absorption and reaction techniques. Separated and integrated CCU processes for propylene carbonate production based on trihexyl(tetradecyl)phosphonium 2-cyanopyrrolide ([P66614][CNPyr]) were successfully modelled utilizing the COSMO-based/Aspen methodology. The performance of both CCU approaches was evaluated attending to energy consumption, utility costs and net CO2 emissions. A novel integrated CCU process achieved promising energy (10.1 MW) and net CO2 emissions (0.23 kg-eq. CO2/kg CO2 absorbed) results, demonstrating not only that dual-functional ILs can be suitable materials for CCU but also the successful integration of IL-based carbon capture and utilization with enhanced process performance.