Integration of membrane contactors and catalytic solvent regeneration for efficient carbon dioxide capture

To develop an energy-efficient and available carbon dioxide (CO2) capture technique with amine-based solvents and membrane contactors (MCs), an innovative technological route was proposed to remove CO2 from industrial flue gas by coupling MCs with catalyst-aided solvent regeneration (MC-CR). A laboratory-scale experimental setup with ceramic membrane module was then designed and built to accurately estimate the performance of the MC-CR route, using aqueous monoethanolamine (MEA) and powder metatitanic acid [TiO(OH)2] as the solvent and catalyst, respectively. The results indicated that the nanofluid effect of the catalyst reduced the mass transfer resistance and promoted a concentration change in the liquid film, resulting in a high CO2 absorption rate.The surface acidic sites of TiO(OH)2 boosted the process of proton transfer in the solvent, thus facilitating the decomposition of carbamate. The CO2 capture efficiency increased by 9.48% and the energy consumption of solvent regeneration considerably decreased by 40.8% at dosage of 2 wt% TiO(OH)2. In addition, matched pressure regulation for gas–liquid flow in the MCs effectively avoided membrane fouling and wetting after 180 min continuous operation. Industrial-scale simulation indicated that the MC-CR route achieved a low capture cost at $46.7/t CO2, a decrease of 28% compared with the cost of the traditional route. This study established the groundwork for developing MC technology as an effective approach for low-cost industrial CO2 capture.