Process dynamics of orange peel essential oil extraction

ABSTRACT In this study, we investigated the extraction of essential oils from orange peels by steam distillation at the pilot plant level. We considered a two-stage mechanism to develop a kinetic model of oil extraction based on process dynamics principles with different dominant mechanisms. The first and second stages were found to be dominated by rapid diffusion and convection washing, and slow diffusion, respectively, with the diffusion speed in the first stage being considerably higher than that in the second. This model considered the inlet steam pressure and orange peel packing factor as independent variables based on their impact on the yield of the essential oils. High correlation coefficients were achieved through straightforward computation, demonstrating the goodness-of-fit of the model. Three important control parameters were determined for each stage, namely gain, time constant, and dead time; they provided an interesting insight into the mass transfer phenomena and served as a useful reference to minimize steam consumption. These control parameters support the design of an extraction process with a favorable impact on the production cost and environment.