Solubility of CO 2 in aqueous mixtures of diethanolamine with methyldiethanolamine and 2-amino-2-methyl-1-propanol

Abstract

Using the static method with recirculation of the vapor phase, experimental data for the solubility of CO 2 in aqueous mixtures of known composition of diethanolamine (DEA) with methyldiethanolamine (MDEA) and DEA with 2-amino-2-methyl-1-propanol (AMP) have been obtained in the CO 2 partial pressure range 3–3000 kPa. The data for DEA–MDEA solutions were obtained at 313.15 K and are reported at four different compositions: 10 wt.% DEA–15 wt.% MDEA, 10 wt.% DEA–20 wt.% MDEA, 20 wt.% DEA–10 wt.% MDEA and 10 wt.% DEA–35 wt.% MDEA, data for the solution of 10 wt.% DEA–20 wt.% MDEA were also obtained at 393.15 K. The data for DEA–AMP solutions were obtained at 313.15 and 373.15 K and are reported at two different compositions: 25 wt.% DEA–5 wt.% AMP and 20 wt.% DEA–10 wt.% AMP. The results are given as the partial pressure ( p) of CO 2 against its mole ratio α (mol CO 2/mol alkanolamine), in the range of temperature studied. The solubility of CO 2 in all the studied systems decreases with an increase in temperature and increases with an increase in the partial pressure of CO 2, at a given temperature, and it is a strong function of the composition of the blend of alkanolamines in solution. The aqueous mixture with 10 wt.% AMP, at 313.15 K, shows higher capacity to absorb CO 2 than any of the other mixtures studied here. From the experimental solubility results, exothermic values of the enthalpy of solution, Δ H s, were derived.