High-pressure viscosity measurements of oily substrates saturated with CO2

FORTUNATTI MONTOYA, M.; HEGEL, P. E.; PEREDA, S.

Buenos Aires

Congreso; 11th World Congress on Chemical Engineering; 2023

World Chemical Engineering Council - Asociación Argentina de Ingeniería Química

Viscosity is a key thermophysical property for reactive and separation processes engineering. Particularly, in the design of packed columns, the viscosity of the liquid phase determines the hydraulic behavior of the column and controls the mass transfer phenomena that governs the separation process. It is well known that the height of theoretical stage in the supercritical CO2 fractionation of vegetable oil-derivatives is highly dependent on the viscosity of the saturated liquid phase [1]. The prediction of viscosity of liquid mixtures, starting from pure compound properties, is a complex challenge. Furthermore, supercritical extraction processes involve mixing a liquid substrate and supercritical CO2, which further increases the complexity of accurate modeling of this property. Despite this, it is a common practice to assume an ideal solution behavior to estimate the properties of the raffinate phase in the column, even though it may present substantial deviations from the actual mixing property [2]. Also, it is worth noting, that viscosity is highly sensitive to CO2 concentration in the saturated phase. Falling-weight high pressure viscometer developed in this work.In this work we show the development of a high-pressure viscosimeter to carry out measurements of saturated liquid mixtures under high-pressure for supercritical process design. A high-pressure falling ball viscometer is used to measure the viscosity of saturated liquid mixtures of oily substrates + CO2 mixtures. This technique has been used by other authors [3] to measure the viscosity of viscous fluids with supercritical solvents. We study the viscosity behavior of glycerol acetates saturated with CO2 (from 40 to 70 mol % CO2 concentration) and the viscosity of lemon oil saturated with CO2 (from 30 to 80 molar % CO2 concentration). The results show viscosity values between 0.9 mPa.s and 20 mPa.s at temperatures between 298 K and 333 K. The new viscosity data is correlated using a modified version of Litovitz equation[ref nuestro paper]. References1.Budich, M., & Brunner, G. (1999). Vapor–liquid equilibrium data and flooding point measurements of the mixture carbon dioxide+ orange peel oil. Fluid phase equilibria, 158, 759-773.2.Fortunatti-Montoya, M., Hegel, P. E., & Pereda, S. (2021). Density and viscosity of mixtures of glycerol acetates saturated with CO2 for the design of a supercritical fractionation column. The Journal of Supercritical Fluids, 168, 105065.3.Schaschke, C. J., Allio, S., & Holmberg, E. (2006). Viscosity measurement of vegetable oil at high pressure. Food and Bioproducts Processing, 84(3), 173-178.