Solubility of CO2 in aqueous mixtures of diethanolamine with methyldiethanolamine and 2-amino-2-methyl-1-propanol

Using the static method with recirculation of the vapor phase, experimental data for the solubility of CO2 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 CO2 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 CO2 against its mole ratio a (mol CO2/mol alkanolamine), in the range of temperature studied. The solubility of CO2 in ail the studied systems decreases with an increase in temperature and increases with an increase in the partial pressure of CO2, 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 CO2 than any of the other mixtures studied here. From the experimental solubility results, exothermic values of the enthalpy of solution, Delta H-s, were derived. (C) 1998 Elsevier Science B.V. All rights reserved.