Comparison of the separation process of crude citronella oil using vacuum fractionation distillation on a pilot plant scale and laboratory scale

Abstract

Crude citronella oil contains a mixture of components such as a group of hydrocarbon monoterpenes compounds, oxygenated monoterpenes, and sesquiterpenes. Therefore, it has low economic value and low functional value. A single component with high purity can be obtained through chemical and physical properties analysis. Based on the physical properties of the constituent components of citronella oil, the boiling points of each component are quite adjacent so that a single component can be separated by the fractionation distillation process. This study aims at determining the optimum condition (temperature, pressure, and reflux ratio) of a pilot plant scale fractionation with 8 meters of the column and the capacity of 200kg (raschig ring packing; temperature range 115-118°C and 118-121°C, reflux ratio 4:1 and 2:1) and comparing it to the laboratory scale (raschig ring packing; temperature range 115-118°C and 118-121°C, reflux ratio 2:1). Although the laboratory scale of fractionation distillation produced good quality rhodinol with 85% purity, the scale-up version of the pilot plant scale still cannot be occupied. For the citronellal fraction, both fractionation distillation process produced poor quality with only 50% purity. This occurred due to the different dimensions that lead to a higher pressure drop. A higher pressure drop will change the optimum temperature conditions.