Solubility of Nitrous Oxide in Alkanolamine Aqueous Solutions

Abstract

The solubility of nitrous oxide (N2O) in alkanolamine aqueous solutions has been measured at (30, 35, and 40) °C. The systems studied are monoethanolamine, diethanolamine, diisopropanolamine, triethanolamine, and 2-amino-2-methyl-1-propanol aqueous solutions. The concentration of amine for monoethanolamine ranges from (1 to 6) kmol·m-3 and for other amines from (0.5 to 3) kmol·m-3. The accuracy of the measurement is estimated to be ± 2%. A semiempirical model of the excess Henry's constant proposed by Wang et al. (1992) was used to correlate the solubility of N2O in amine solutions. The parameters of the correlation were determined from the measured solubility data and the available data in the open literature. For a wide temperature range from (15 to 75) °C, the obtained correlation has been shown to represent reasonably the solubility of N2O in six amine aqueous solutions: MEA, DEA, DIPA, TEA, MDEA, and AMP. For the purpose of process design, the obtained correlations are, in general, satisfactory for estimating the solubility of N2O in amine solutions, which in turn can be used to estimate the correct free-gas solubility of CO2 in amines.