Solvent free microwave extraction (SFME) has been demonstrated to be feasible in extraction of essential oils from botanical materials. The benefits are no need for any solvent aside from the water naturally in the botanical material and a significant reduction in environmental impact for large scale production processes. However, the aerosol formed by the microwave energy applied to the plant material is inefficiently collected with common condensers. Air coming from the open ends of extraction systems creates the boundary layer effects for the condenser, which makes essential oil collecting inefficient. To solve this problem, the development of a direct contact condenser is in development for the collection step. My research is to model the collision between the aerosol particles and the liquid droplets from the spray nozzles in the direct contact condenser. The goal in this project is to improve the collection efficiency by increasing adequate collision between the two sorts of droplets. Through the use of the model program developed, the collection efficiency of direct contact condenser will be improved to increase production oil.
Based on our computation, a bigger oil droplet leads to a greater captured fraction of oil aerosol, while the bigger water droplet decreases the captured fraction with fixed volume flow rate of water. Meanwhile, an easy way to collect more mint oil is to employ a lot of sprays to increase the rows of water droplets. However, this result is needed to be justified by more computations with a large number of oil aerosols.