Reaction kinetics of CO₂ capture into AMP/PZ/DME solid-liquid biphasic solvent

The non-aqueous solid-liquid biphasic solvent of 2-amino-2-methyl-1-propanol (AMP)/piperazine (PZ)/dipropylene glycol dimethyl ether (DME) features a high CO₂ absorption loading, favorable phase separation behavior and high regeneration efficiency. Different with the liquid-liquid phase change solvent, the reaction kinetics of CO₂ capture into solid-liquid biphasic solvent was rarely studied. In the present work, the reaction kinetics of CO₂ absorption into AMP/PZ/DME solid-liquid biphasic solvent was investigated into the double stirred kettle reactor. The absorption reaction followed a pseudo-first-order kinetic model according to the zwitterion mechanism. The overall reaction rate constant (k_ov) and the enhancement factor (E) of CO₂ absorption both increased with increasing temperature. The total mass transfer resistance of the absorbent decreased with increasing temperature and increased with increasing absorption loading, so the higher reaction temperature was conducive to the absorption, and the liquid phase mass transfer resistance was the main factor affecting the absorption rate.