Experimental assessment of properties for a non-aqueous and precipitating alkanolamine absorption system

Sammanfattning: With increasing atmospheric carbon dioxide (CO2) concentrations, energy efficient carbon capture and storage (CCS) technologies could prove important to enable reductions in the global CO2 emissions. The aim was to investigate a novel, non-aqueous, and precipitating chemical absorption system of dimethyl sulfoxide (DMSO) and 2-amino-2-methyl-1-propanol (AMP), which forms solid carbamate salt crystals with CO2. Four properties of mixtures of water, AMP, and DMSO, with or without CO2, were evaluated experimentally. The four properties were the settling velocities, the freezing temperatures, the densities, and the viscosities. Higher settling velocities being registered at higher temperatures and for mixtures with larger particles. It was shown that the freezing temperatures of mixtures of water, AMP, and DMSO, both with or without CO2, were lower than the freezing temperature of pure DMSO or AMP. Another finding was that when the water content increased, the freezing temperature decreased. The effect of the temperature, the CO2-loading, and the AMP- and water concentration, on the density and viscosity of the liquid mixtures, were also investigated. The results showed that if the weight percentage of AMP or if the temperature is increased, the density decreased, while the opposite was shown for increasing water content and amounts of absorbed CO2. Furthermore, the experimentally derived densities for CO2-loaded mixtures could be well estimated, although slightly underestimated, from experimental values for unloaded mixtures. The viscosity was increased at higher CO2-loadings, higher water concentration, but also when the AMP concentration increased. Higher temperatures led to lower viscosities of unloaded liquid mixtures. Although less reliable, the results indicate that for the mixtures with high CO2-loadings and high AMP concentration, much higher viscosities can be expected.