Design and Analysis of Small Scale Essential Oil Steam Distillery for Better Energy Utilization

Abstract The essential oil industry, an agro-based sector, involves cultivation and distillation activities and can manufacture products using various methods. Steam distillation accounts for 93% of essential oil extraction, while the remaining 7% is extracted using other methods that employ thermal energy. In Ethiopia, the abundance of aromatic plant leaves has made essential oils a primary raw material for industries. Steam distillation, a well-established technology, utilizes thermal energy in the extraction process. In this method, steam is produced in a satellite station (boiler) and fed to a still where the biomass is boiled to extract the oil. The extracted oil is then cooled in a condenser. The density difference method is used to separate the liquid mixture (water and oil) in a separator. The current steam distillation equipment experiences significant energy loss in the steam generator and waste water after oil separation. This study aimed to design and manufacture a prototype of steam distillation equipment. The developed essential oil extraction plant was tested using eucalyptus leaves. The results showed that steam distillation yielded 0.188 kg or 15.5 mL of essential oil per batch from 10 kg of eucalyptus leaves with a total water volume of 20 liters. Additionally, the results indicated that the volume of essential oil increases with temperature while maintaining a constant heating time. Reducing pressure allowed for the extraction of essential oils at relatively lower temperatures and shorter heating times. Energy losses were minimized by recycling hot waste water back to the boiler and using improved biomass stoves.