Modeling the supercritical desorption of orange essential oil from a silica-gel bed

One of the most important byproducts of the orange juice industry is the oi l phase. This is a mixture of terpenes, alcohols, and aldehydes, dissolved in approximately 96% limonene. To satisfactorily use oil phase as an ingred ient in the food and cosmetics industries separation of the limonene is req uired. One possibility is to use a fixed bed of silica gel to remove the fi ght or aroma compounds from the limonene. The aroma substances are then ext racted from the bed of silica gel using supercritical carbon dioxide. This work deals with the modeling of the desorption step of the process using ma ss balance equations coupled with the Langmuir equilibrium isotherm. Data t aken from the literature for the overall extraction curves were used togeth er with empirical correlations to calculate the concentration profile of so lute in the supercritical phase at the bed outlet. The system of equations was solved by the finite volume technique. The overall extraction curves ca lculated were in good agreement with the experimental ones.