VISCOSITY ESTIMATION IN BINARY AND TERNARY SUPERCRITICAL FLUID MIXTURES CONTAINING CARBON DIOXIDE USING A SUPERCRITICAL FLUID CHROMATOGRAPH

Design of industrial processes that use supercritical fluids requires knowing the viscosity to predict the pressure drop required to achieve a given flow. The viscosities of many pure substances such as carbon dioxide, methanol, and other commonly used organic solvents have been published. Far less information is available for binary mixtures of carbon dioxide with organic modifiers, and almost no information is available for ternary mixtures. We present a simple method for estimating viscosity based on the expected proportionality of viscosity with pressure drop when a fluid is pumped through a packed column. Estimates can be made quickly using a supercritical fluid chromatograph. We report estimated viscosities for mixtures of carbon dioxide with methanol, ethanol, n-propanol, cyclohexane, toluene, and 95% ethanol.