Determination of Essential Oil Losses in Large-Scale Industrial Distillation and Fractionation Process of Essential Oil on Industrial Scale of Turkish Oregano ( Origanum onites L.)

Due to the inappropriate design of conventional industrial distillation systems, losses in the essential oil occur since steam does not penetrate homogeneously into the plant material. For this purpose, this study investigates the essential oil losses in industrial distillation systems using Origanum onites L., and the effect of fractionations on essential oil compounds. After after the distillation process, the remaining essential oils in the samples taken from different areas of the distillation boiler were determined by re-distillation under laboratory conditions. In addition, it aims to investigate time-dependent fractionation in microwave-assisted, and standard conventional steam distillation systems. Time-dependent oil amount (fractionation) was studied at 10, 25, and 50 min in microwave-assisted distillation and at 10, 25, 50, 100, and 150 min in conventional distillation. All measurements in the study were made in October 2023. The oil compositions of these samples were analyzed by Gas Chromatography/Mass Spectrometry (GC-MS). It was determined that there were losses due to the inability of steam to penetrate the inner parts during distillation in plants such as small-leaved oregano. While the loss of essential oil is 42.86% in the inner area of the distillation boiler where steam penetrates less, this loss amount of essential oil decreases to 2% in the areas where steam penetrates more. In GC-MS analyses, the carvacrol ratio was measured to be higher in the sample remaining after distillation. As a result, new mechanical designs are needed to increase distillation efficiency for plant species such as smallleaf oregano in large-scale industrial distillation. Since 97% of the total oil was obtained after 100 min in conventional distillation processes, not extending the distillation time any further is vital in terms of energy and operating costs.