Thirteen terpenes forming a mixture that is characteristic of peel essential oils have been simultaneously adsorbed on silica gel from supercritical CO2. They have been divided into four pseudo-components according to the similarity of their behavior during the adsorption process. An equilibrium model based on differential mass balances written for the fluid and the solid phase was proposed. The numerical integration of the four partial differential equations resulting from the model was performed using the Wendroff method. The computational molecule was modified with respect to the original method. A molecule of variable geometry was adopted to avoid numerical oscillatins in the solution of the problem. The breakthrough time and the maximum concentration of the four pseudo-components were fairly well modelled. The consecutive displacement of the various pseudo-components by those more strongly adsorbed was also well described by the proposed model when compared to the experimental data. The simulation of the concentration profiles of the pseudo-components along the adsorption bed at increasing processing times was also proposed. It was possible to describe the onset and the evolution of displacement waves of the pseudo-components along the bed.