Experimental investigation of the density and viscosity of CO2-loaded aqueous alkanolamine solutions

The density and viscosity of aqueous methyldiethanolamine (MDEA) solution (45 mass%), as well as it’s aqueous mixtures with 2-amino-2-methyl-1-propanol (AMP) (40 mass% MDEA + 5 mass% AMP) and diisopropanolamine (DIPA) (40 mass% MDEA + 5 mass% DIPA) were experimentally measured under CO2 gas loading. The measurements were performed simultaneously with the solubility of CO2 at temperatures from (303.15 to 363.15) K and pressures up to 2.0 MPa by using the experimental setup recently developed in our laboratory [21] (Jalili et al., 2015). Acid gas loading has a significant effect on the density and viscosity of solutions. It was observed that the density and viscosity of mixtures decrease by increasing temperature. The density of fresh (unloaded) solutions follows the order: MDEA > MDEA + AMP > MDEA + DIPA, whereas, their viscosity follows: MDEA ≤ MDEA + AMP > MDEA + DIPA in the entire temperature range studied in this work. The density of solutions increases by about 0.7% to at most 6.4%, whereas the viscosity increases from about 8% up to about 67% at a CO2 loading of 0.5 mol CO2/mol amine compared to fresh solutions. The modified Setchnow correlation was used to predict the densities and viscosities of all solutions used in this work.