No abstract

No abstract

Shifting from aqueous to water lean solvents has been evaluated as a mean for increasing the mass transfer rates in regular chemical solvents with amines. An array of amines (monoethanolamine, 2-methylpiperazine and N-methyl diethanolamine) and diluents (sulfolane, ethylene glycol, 1-methylimidazole, dimethyl sulfoxide, N-methyl-2-pyrrolidinone) has been analyzed.Addition of organic diluents seem to generally induce both a shift in chemical equilibrium and an increase in mass transfer rates for a fixed CO2 partial pressure, though not necessarily for a fixed CO2 loading. However, these relative advantages in terms of mass transfer rates decrease the more loaded the water lean solvent is. The equilibrium shift caused by organic diluents has been evaluated in terms of de-stabilization of the species in the solvent, which for monoethanolamine-based solvents can be easily related to a decrease in dielectric permittivity. However, this analysis indicates that such treatment is insufficient for other types of water-lean solvents, suggesting that different kinds of intermolecular interactions should also be considered in future studies.

Experimental measurements and modelling of the density and viscosity of binary solutions of imidazole, 2-methylimidazole, 2,4,5-trimethylimidazole and 1,2,4,5-tetramethylimidazole with water have been conducted. Parameterization of viscosity data was conducted using a NRTL-model, with AARD of 1% for imidazole, 0.8% for 2-methylimidazole, 3% for 2,4,5-trimethylimidazole and 5% for 1,2,4,5tetramethylimidazole. The density correlations represent the experimental data for imidazole solutions with AARD of 0.1% for all four imidazoles. Viscosities of aqueous imidazole solutions were found to 2 increase upon charging solutions with CO2. Vapor-liquid equilibrium (P, T, x, y) in the range from 313 to 373 K for the aqueous solutions were performed using ebulliometer. The results show that the tested imidazoles exhibit low vapor pressures in aqueous solutions. Finally, it was found there is an insignificant dependence of water activity on temperature within the range of the present study.