Thermodynamic and kinetic modeling of a novel polyamine-based solvent for energy-efficient CO2 capture with energy analysis

Abstract

Polyamine-based solvents (PSs) are regarded to be emerging energy-efficient alternatives to conventional solvents for use in absorption-based CO2 capture. In this paper, we propose a novel polyamine, 3,3′-iminobis (N,N-dimethylpropylamine) (IBDMPA), based aqueous amine solution. The solvent was composed of 45 wt% IBDMPA and 48 wt% water, with a non-amine chemical making up the rest of the mixture. Thermodynamic modeling work of CO2 solubility was carried out using Aspen Plus® V10, and the Elec-NRTL model with the Redlick-Kwong equation was integrated with the equilibrium model. For CO2 solubility modeling, measurement data was obtained from the equilibrium cell and 1H/13C nuclear magnetic resonance and used to validate the CO2 solubility modeling. Kinetic modeling of the proposed PS was conducted using a tertiary amine reaction mechanism, and the measurement data for the overall mass transfer coefficient was obtained using a wetted wall column. PS has cyclic capacity of approximately 1.05 mol-CO2/mol-IBD and overall mass transfer coefficient of 2.51e-03 mol m−2 kPa−1 sec−1, which is much higher than that of conventional MEA 30 wt% solution (0.35 mol-CO2/mol-MEA and 1.05e-03 mol m−2 kPa−1 sec−1). As a result, the minimum energy required for reboiler was calculated to be 2.3 GJ t-CO2−1 at 1 bara of the desorber pressure. Such a low energy demand value supports the commercial feasibility of polyamine-based solvents for large-scale CO2 capture.