Dynamic model of a countercurrent packed column operating at high pressure conditions

A dynamic simulation model of a countercurrent packed column operating at supercritical fluid (SCF) conditions is presented. The model was developed and applied to a case study involving the fractionation of a binary mixture of squalene and methyl oleate using supercritical carbon dioxide. The purpose of the separation process is to remove the methyl oleate from the solution and concentrate squalene in the raffinate phase. The final model comprises the differential material balances in the packed column and algebraic equations describing the thermodynamic phase equilibrium, mass transfer and the hydrodynamics of the two countercurrent phases. The model was validated by carrying out a series of experiments in a lab-scale continuous SCF extraction unit. A good agreement was obtained between measured and predicted composition profile of the outlet streams over time.