Viscosity of compressed CO2-saturated n-alkanes: CO2/n-hexane, CO2/n-decane, and CO2/n-tetradecane

Abstract

Many industrial processes utilize a liquid phase with large amounts of dissolved gases at elevated pressures; e.g. CO2 capture; enhanced oil recovery; CO2-expanded Liquids; etc. In order to understand the transport properties, the experimental dynamic viscosity and calculated kinematic viscosity are reported for binary systems of CO2-saturated n-alkanes, n-hexane, n-decane, or n-tetradecane, at 25°, 40°, and 55°C and pressures up to 107bar. The global phase behavior was investigated and transitions from vapor-liquid equilibrium were confirmed. Equation of state modeling of literature vapor-liquid equilibrium data was used to determine the compositions at the conditions of interest. Increasing composition of CO2 (pressure) results in significant decrease in the viscosity of the binary mixtures. Measured viscosities decrease in a relatively manner at low to moderate compositions of CO2 in liquid phase. “Excess viscosities” were calculated to help understand the phenomena. These properties have implications for fluid transport, heat transfer, and mass transfer.