Physical Properties of Precipitating Amine System Using 2-Amino-2-Methyl-1-Propanol in Dimethyl Sulfoxide

Abstract

In order to evaluate a precipitating absorption system consisting of 2-amino-2-methyl-1-propanol (AMP) and dimethyl sulfoxide (DMSO) on a pilot scale, the physical properties of the system need to be determined. In this work, the freezing point (measured as melting temperature), density and viscosity of 25 wt% AMP in DMSO was evaluated at different CO2 loadings. The density and viscosity were also evaluated at a higher amine content (50 wt%). Since DMSO is hygroscopic, likely resulting in water accumulation during operation with humid flue gases, two different water concentrations (5 and 10 wt%) were also investigated. The melting temperature was found to be lower with higher water content in the solution and, in most cases, higher at higher CO2 loadings. However, all mixed solutions (both unloaded and loaded) had a lower melting temperature than pure AMP and DMSO. The density of the solutions increased slightly with increased water content, whereas a higher amine content led to lower densities. The densities also increased with increasing loading. Assuming constant volume and adding the weight of absorbed CO2 to the density of the unloaded solution gave a good approximation of the overall density of the CO2-loaded mixtures (within 2% of the experimental value). The viscosity of the mixtures increased with both water and amine content, and for the unloaded solutions, the highest viscosity obtained was for 50AD-10W at 13.2 mPas. The apparent viscosity of the slurries increased with increasing loading.

Keywords: AMP, DMSO, CO2, absorption, density, viscosity