Characterization and Correlations of CO2 Absorption Performance into Aqueous Amine Blended Solution of Monoethanolamine (MEA) and N,N-Dimethylethanolamine (DMEA) in a Packed Column

To get a more accurate mass transfer coefficient model of CO2 into aqueous monoethanolamine (MEA)/N,N-dimethylethanolamine (DMEA) solution in a packed column, the Henry’s law constant, equilibrium CO2 solubility, volumetric overall mass transfer coefficient (KGav), overall gas-phase mass transfer coefficient (KG), and effective gas–liquid interfacial area (av) were comprehensively studied. The Henry’s law constant was obtained using a jacketed stirred glass reactor, and the equilibrium CO2 solubility was investigated using a bubbling absorption reactor. Additionally, the mass transfer performance was measured and evaluated experimentally in a packed column with DX-Type structured packing in terms of KGav, KG, and av. These experiments were conducted under the MEA/DMEA concentration of 6 kmol·m–3 with ratio of 5:1. The dynamic changes of solubility, species concentration, and absorption heat of solution were analyzed under different CO2 loadings. The experimental results showed that the relationship of successive absorption without synergistic effect from the perspective of equilibrium state for the MEA/DMEA solution and the blended MEA/DMEA solution can reduce the CO2 absorption heat compared to that of MEA solution. Furthermore, a predicted model of KGav, which should be suitable for different solution systems with DX-Type structured packings in a packed column, was also proposed and developed based on the KG model and av model in this work.