Solubility of Nitrous Oxide in Aqueous Methyldiethanolamine Solutions

Abstract

The solubility of nitrous oxide in a 20 mass % aqueous solution of methyldiethanolamine (MDEA) was measured at the temperatures of (283.15, 298.15, 323.15, 348.15, 373.15, and 398.15) K at pressures up to 20.37 MPa. In addition, the solubility of nitrous oxide in a 40 mass % aqueous solution of MDEA was measured at temperatures of (274.15, 283.15, 298.15, 323.15, 348.15, 373.15, and 398.15) K at pressures up to 20.57 MPa. The individual data sets were correlated with the Peng–Robinson equation of state with temperature-dependent binary interaction parameters. The correlation approach reproduced the experimental data to within an overall average percent deviation in the N2O liquid-phase mole fraction of 3.5% and 4.5% in the 20 mass % and 40 mass % MDEA solutions, respectively. The Peng–Robinson equation of state combined with the Krichevsky–Ilinskaya equation were used to obtain Henry’s law constants, partial molar volumes at infinite dilution, and Margules parameters for these systems. The new Henry’s law constants were correlated with the Li–Mather model. The new binary (N2O + MDEA) interaction energy parameters correlated the Henry’s law constants of N2O in both of the aqueous MDEA solutions to within 1.2%. As part of the solubility and Henry’s law constant model development, new models for the density of pure MDEA and (MDEA + H2O) solutions were developed. These models could reproduce the literature density data of pure MDEA and aqueous MDEA solutions to within 0.10% and 0.13%, respectively.