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The present work analyzes and compares the carbon dioxide absorption process in aqueous solutions of different amines (MEA, monoethanolamine; DEA, diethanolamine; TEA, triethanolamine). This study evaluates the influence of the reagents nature upon absorption using a semicontinuous regime in a bubble contactor. 13C and 1H nuclear magnetic resonance (NMR) spectroscopy has been used to analyze species (reagents and/or products) in the reaction medium. In this way, the influence of the amino group substitution degree and carbon dioxide loading upon the chemical absorption mechanism were analyzed.

The process of pure CO2 absorption by aqueous solutions of 2-methyl-amino-ethanol (MAE) has been studied in relation to the thermal effects of the operation. This study evaluates the consequences of heat effects during absorption and chemical reaction. The experiments were performed in a stirred tank reactor operated in batches with respect to the gas–liquid phases, having a plane interfacial area. The working variables considered were the alkanolamine concentration within the interval 0.1–2.0 kmol/m3 and the temperature in the range 288–313 K. From the results, it is deduced that the CO2 absorption at high pressures in aqueous MAE solutions, occur in the instantaneous reaction regime with high interface temperature. An expression is proposed to relate the experimental results to the initial concentration of alkanolamine and at the same time enable the determination of the interfacial temperature (Ts). In relation to temperature in the bulk liquid phase (TB), increases (Ts – TB) close to 43 K were determi...