A continuous process for steam distillation of essential oils was described in a previous article. Due to the continued widespread interest in this subject, we’ll provide further insight into the details of the process, as well as equipment specifications and cost estimates for distillation plants of various sizes.
The process consists of a totally insulated pneumatic conveying system using superheated steam as a carrier gas and arranged in such a way as to provide a two-stage, counter-current flow of the gas and the solid phase. During the transport, which is made to last 30 seconds, the oil goes into the vapor phase and exits the system with the steam after filtration. Following total condensation of the gas stream, the oil is separated from the water condensate in a gravity separator. The water phase is treated and recycled to the boiler. The dry pulverized stream of spent solids is blown directly into the boiler biomass furnace to generate steam and electric power for the process. AII the components and the design characteristics of the system follow the laws of pneumatic conveying, which affords a quick and convenient way of scaling the system up and down.
Theory
The basic concept of our continuous essential oil distillation process evolved from the following considerations, which were based on prior laboratory research by the authors:
