KINETICS AND MODELING OF OIL EXTRACTION FROM VIETNAM LEMONGRASS BY STEAM DISTILLATION

Essential oils from parts of plants such as stump, flower, kernel, and seed are usually produced by extraction, distillation and mechanical press. In practice, steam distillation is commonly used for the extraction of crude essential oils since it is not only a simple process but also applicable at various scales. Furthermore, the method makes it possible for a keeping of precious components of the oils unchanged. Therefore, studies on kinetics and modeling of the essential oil steam distillation are needed for the optimization of the operating conditions, energy requirement, and the process scale-up. In this work, experiments of lemongrass (Cymbopogon Citratus) steam distillation were carried out and a kinetics model was developed for the extraction of lemongrass essential oil. Raw materials were pretreated by natural drying, primarily crushing and chopping prior to the distillation. The oil yield obtained is in the range of 2.1 – 2.9 ml/kg of raw materials. Composition of the crude oil extracted was measured by GC-MS. Measurements showing that the oil product contains 70.5 % of precious component–Citral in which Neral is 29.8 % and Geranial 40.7 %. The kinetics parameters were estimated from experimental data conducted at various operating conditions for different preparation of the raw materials. The process rate constant (extraction rate constant) describing the extraction efficiency obtained from this study is varied from 0.02 to 0.027 min -1 using first-order kinetic model.