recycled using normal or vacuum evaporation. The treated peel is fed into anaerobic digester to produce methane. The
mixture of hexane and limonene out from filtration which has about 0.55 L limonene per m3 of hexane is fed into rotary
vacuumevaporator operated at 70∘C in order to evaporate the volatile hexane and separate it from the limonene.The vapor
of hexane is condensed and recycled back to the pretreatment vessel for extraction of more limonene from fresh peels.