Adaptable microwave assisted distillation system design for oil extraction from medicinal and aromatic plants

Essential oils from lavender species are very common in complementary/alternative medicine and are widely used in aromatherapy to reduce stress, increase relaxation, and improve sleep quality. Since the essential oil yield of the hybrid Lavandula plant called Lavandula intermedia, lavandin, is higher than other species, this species is more preferred in production. The extraction of essential oil from this plant has been done using conventional steam distillation (CD) systems, where both time (2-3 hours) and energy consumption are high and this is reflected in unit costs. Although microwave-assisted systems (MWAD) proposed as an alternative to this do not change the quality of the essential oil and shorten the distillation time considerably, almost all of the studies in the literature have been carried out on very small-scale plants under laboratory conditions. As an innovation, in this study, an industrial type MWAD system is designed to test the results of microwave (MW) power applied to Lavender species at different powers (300-400-450-500 and 600 W) and durations (10, 20 and 30 min). Furthermore, the performances of CD and MWAD systems for Lavender plant are compared in terms of energy consumption, oil yield and quality. In CD system, 4×3 magnetrons are optimally mounted around the boiler and these magnetrons are excited by the control circuit on the panel. The essential oils obtained from the tests are subjected to GC-MS analysis and the analysis results are grouped by Cluster method in SPSS program. As a result of the experiments, it is noted that the application of microwave (MW) power did not significantly change the essential oil components, but increasing the MW power too much caused some decrease in the results of linalool and linalyl acetate. It is observed that MW power applied in the MWAD system slightly increased the essential oil yield (max. 10%) and shortened the distillation time by 50% compared to the GBD system.