Thermodynamic Modeling of an Aqueous N, N‐Dimethyldipropylenetriamine and Benzylamine Blend for Efficient CO₂ Capture

This study evaluates the carbon dioxide (CO₂) capture capabilities of a novel aqueous blend of N,N-dimethyldipropylenetriamine (DMDPTA) and benzylamine (BA). The solvent properties such density, vapor- liquid equilibrium (VLE) of CO₂ in the solvent, CO₂ absorption enthalpy are evaluated experimentally for solvent composition of (5 mass % DMDPTA+25 mass % BA), (10 mass % DMDPTA+20 mass % BA), and (15 mass % DMDPTA+15 mass % BA). Solvent density were measured in the temperature range of 303 K-333 K and correlated using Redlich-Kister excess molar volume model, with a low average absolute relative deviation (AARD) of 0.014. VLE data was measured using a custom-made stirred VLE cell, within CO₂ partial pressure range of 2-200 kPa and at temperatures 313 K, 323 K and 333 K. Equilibrium CO₂ solubility data were correlated using a modified Kent-Eisenberg model, achieving an AARD of 1.5 %. Enthalpy of CO₂ absorption was measured at 313 K using a Meter Toledo reaction calorimeter. Results indicated that under similar process conditions and solvent composition, (DMDPTA+BA) blends exhibited significantly higher CO₂ loading and low absorption enthalpy compared to aqueous BA and monoethanolamine solvent alone indicating the potential of (DMDPTA+BA) blend as efficient CO₂ capture solvent.