Kinetics analysis and regeneration performance of 1-butyl-3-methylimidazolium glycinate solutions for CO2 capture

• The effect factors of CO2 absorption into [C4mim][Gly] solution were discussed.
• The effect factors of CO2 regeneration from saturated solution were discussed.
• The kinetics of CO2 absorption into [C4mim][Gly] solution was analyzed.
• The reaction rate constant (k2) and activity energy were calculated out.
• The group linked with methylimidazolium had little effect on activation energy.

CO2 absorption performance into 1-butyl-3-methylimidazolium glycinate ([C4mim][Gly]) solution were investigated to evaluate the effect of absorption temperature, absorbent concentration and the content of CO2 at inlet using a double stirred-cell absorber at atmospheric pressure, where the kinetic parameters were calculated in this work. Meanwhile, the density, viscosity, diffusivity of CO2 and solubility of CO2 into [C4mim][Gly] solution were investigated. Compared to MEA and DEA, the effect of temperature, time and cycles on the desorption efficiency of CO2 were discussed. And the kinetic data of CO2 absorption in the so-called pseudo-first-order regime were calculated in order to determine the reaction rate expression and reaction rate constant of CO2 into aqueous [C4mim][Gly] solutions. The result of kinetic analysis showed that the values of Hatta number (Ha) and the enhancement factor (E) increased with the increase of [C4mim][Gly] concentration and absorption temperature, respectively. The activation energy was calculated to be approximately 41.89 kJ mol−1, and the second-order rate constant was expressed as following equation: k2=1.3460×1010exp-5038T.