Microwave Extraction of Essential Oil from Peppermint - Field Trial

This is an author's manuscript. This paper was presented at the 2nd Global Congress on Microwave Energy Applications (2GCMEA). July 23-27, 2012. Hilton Long Beach. Long Beach, CA. USA Session D6.6.An in-field test of the solvent free microwave extraction of peppermint oil was held in mid-August 2009 at Butler Valley Farms in Stayton, Oregon. Results of the trial were limited due to rapid coalescence of the mint oil prior to entry into the separator. This resulted in no mint oil actually received at the normal receiving site. A small quantity of mint oil was discovered during take-down and laboratory analysis indicates it to be pure. For the Solvent Free Microwave Extraction (SFME) system to work effectively in the large scale (farm operation) condition, it is believed that a significant change in the condensation apparatus will be necessary. Work demonstrating a solution to that issue will be presented. The 100KW 915MHz microwave unit (normally used for drying) performed well in the farm environment and after significant modifications, feed systems were developed to take chopped mint hay from existing mint tubs and move it into the extractor. The results of this field trial were adequate to enable design improvements for future development