CO2 absorption kinetic study based on non-aqueous mixed solvent system of amino acid ionic liquids with polyethylene glycol as solvent

The non-aqueous mixed solvent system based on amino acid ionic liquids(AAILs)and polyethylene glycol 400(PEG400)shows many advantages, such as extremely low vapor pressure, good thermal stability, low viscosity and regeneration energy, high CO2 capacity and selectivity, which is suitable for the pre-combustion process facing high absorption temperature and pressure conditions. The CO2 absorption rates for three kinds of AAILs with tetrabutylphosphonium ([P4444]+) as cation, glycine(Gly), alanine(Ala), proline(Pro)as anions in PEG400 were determined by pressure drop method, and then the relevant absorption kinetic model was developed. The absorption rate were ranked as [P4444][Gly]-PEG400>[P4444][Pro]-PEG400>[P4444][Ala]-PEG400 at 333.15K and [P4444][Pro]-PEG400>[P4444][Gly]-PEG400>[P4444][Ala]-PEG400 at 373.15K. According to the absorption kinetic results, the CO2 absorption by AAIL-PEG400 system was fast reaction. Based on the absorption model, the key kinetic parameters were obtained, providing the basic data and principle of design for the coming industrial development and process design. © 2018, Chemical Industry Press. All right reserved.