Mass transfer model for supercritical fluid extraction tests

A mass transfer model using a linear equilibrium isotherm is presented for the static and dynamic stages of supercritical fluid extraction tests. In t he static stage the fraction extracted is a function of a dimensionless tim e and a dimensionless equilibrium parameter. In the dynamic stage the fract ion recovered is a function of a different dimensionless time, the same equ ilibrium parameter, and a dimensionless mass transfer parameter. Fitting th e model to experimental extraction curves showed that increasing the pressu re or density increases the equilibrium constant and decreases the overall mass transfer coefficient.