OPTIMISATION OF THE SUPERCRITICAL FLUID EXTRACTION OF VETIVER ROOTS

Abstract

: The market projections for growth in both the essential and oleoresins market demonstrate a unique opportunity for Trinidad and Tobago to enter the business. Since an established bay tree plantation in Tobago cannot provide the raw material to operate a natural extracts plant for an entire year, the operation could be supplemented by the production of vetiver oil using vetiver roots that are grown and supplied by Tobago farmers. The chosen extraction technique is Supercritical Fluid Extraction (SFE) using carbon dioxide solvent since SFE was found to be more efficient and versatile than the traditional technique of Steam Distillation Extraction (SDE). To determine the optimum process conditions, a laboratory scale SFE programme was implemented using indigenous vetiver roots. The interactive effects of the operating parameters of pressures, temperatures and flowrates with respect to the oil yield were ascertained using Design of Experiments (DOE) which entailed the execution of 11 experimental runs. An ANOVA test produced an R 2 value 0.9864 and the optimum conditions were found to be – 220 Bar at 50 o C at an exit CO 2 flow rate of 2ml/min. The yield at this optimum condition was 4.75 wt. % which was considerably higher than yields reported in the literature. An initial evaluation of the economic viability of the project indicated an IRR of 28%, making the project well worthy of further development towards potential commercialisation.