We present a dynamic simulation model for a counter-current structured packing column operating under supercritical fluid conditions. The model accounts for mass and heat transfer throughout the column and axial effects on temperature profiles are considered. The model has been 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 physical properties of both phases, which are necessary to solve the equations in the model, were estimated based on data taken from the literature. For each physical property, a correlation was developed in terms of pressure, temperature and phase compositions. The validation of the model was made by carrying out a series of experiments in a pilot-scale apparatus. The experiments were conducted at: 313≤T≤343K, 11.7≤P≤19.0 MPa, and 10≤gas-to-liquid flowratio≤20. Disturbances on selected load variables and operation parameters were applied and the dynamic response of the SFE unit tracked. The dynamic optimization studies were carried out using the Dynamic Optimization Module of gPROMS.

References:

[1] Ruivo, R., Paiva, A., Mota, J.P.B., Simões, P., Dynamic model of a countercurrent packed column operating at high pressure conditions. Journal of Supercritical Fluids, 32, 2004, 183. [2] Ruivo, Cebola, M. J., Simões, P., Nunes da Ponte, M., Fractionation of Edible Oil Model Mixtures by Supercritical Carbon Dioxide in a Packed Column – Part I: Experimental Results, Ind. Eng. Chem. Res., vol. 40(7), 2001, p. 1706 [3] Ruivo, Cebola, M. J., Simões, P., Nunes da Ponte, M., Fractionation of Edible Oil Model Mixtures by Supercritical Carbon Dioxide in a Packed Column – Part II: A Mass Transfer Study, Ind. Eng. Chem. Res., vol. 41, 2002, p. 2305