Supercritical carbon dioxide fractionation of lemon oil by means of a batch process with an external reflux

The deterpenation of cold-pressed lemon peel oil by means of supercritical carbon dioxide was carried out both in a simple batch mode and by means of a batch process with a rectification column. The simple batch process provided experimental data of vapour phase loading at temperature 315-323-333 K and pressure ranging from 8.4 to 10.5 MPa. This process allowed the production of folded oils with reasonable solvent to feed ratio, but led to low recovery of oxygenated compounds in the raffinate. In order to increase the recovery of these valuable compounds, a batch process with an external reflux of extract was performed in a laboratory plant, investigating the effect of temperature, pressure and reflux ratio. The operational conditions that led to lower solvent to feed ratio, for a stated oxygenated concentration in the raffinate, were found at temperature of 333 K and pressure around 10.0 MPa. The obtained values for the recovery of oxygenated compounds ranged from 0.82 to nearly 1, with a reflux ratio varying from 1.4 to 9.