Kinetic modeling of Polyamine-based Water-Lean solvents for CO2 capture: Reverse temperature dependence of the overall mass transfer coefficient

Abstract

Amine-based water-lean solvents (WLS) are promising energy-saving alternatives to the aqueous amine solutions for CO2 capture. Herein, we determined the apparent kinetic parameters of WLS containing 3,3′-iminobis(N,N-dimethylpropylamine) (60 wt%), water (10–20 wt%), and a non-amine chemical (balance). For CO2 absorption rate modeling, the termolecular reaction model and reaction rate model of tertiary amines were incorporated into the equilibrium model proposed by previous work, and the absorption rate of CO2 was estimated using a wetted wall column-based apparatus. The average CO2 absorption rates of the studied 10 wt%–H2O WLS at 313 and 333 K were approximately 5.0e-03 and 4.0e-03 mol/m2∙kPa∙s, respectively, which were much higher than that of a conventional aqueous amine solvent for CO2 capture. In addition, we observed that the overall mass transfer coefficient decreased with increasing temperature in low content water of WLS. This is due to the change of physical properties (Henry's law constant and diffusion coefficient) of WLS with decreasing water concentration. In this work, the cause of the reverse temperature dependence of WLS was investigated and verified through experiments and modeling.