The Solvent extraction plants are used where oil is extracted from oil seeds like soyabean, sunflower, cottonseed, other oil seeds and oil cakes like mustard cake, groundnut cake and rice bran.
The process consists of extracting most of the oil from prepared raw material by Counter Current Extraction for a calculated period of time. The extracted meal from extractor is transferred for recovery of entrapped solvent to desolventizer toaster, where solvent from the meal is removed as well as the desolventized material is conditioned by controlling and adjusting the temperature and moisture. The conditioned desolventized toasted meal is sent for bagging. Vapors from desolventizer toaster are carried to condenser for vapor / solvent condensation & recovery of solvent via Economizer. Solvent after removal of moisture is re-circulated. Miscella after fine separation using Hydro Clones is pumped / feed to distillation section comprising of Evaporator, Heater, and Vapor condensing unit. Miscella is transferred to Evaporator via economizer where miscella is initially heated up and part of solvent is recovered by utilizing heat of vapors from desolventising unit.
Maximum solvent from oil – solvent mixture is recovered at distillation stage. Final solvent traces from oil coming out from distillation zone are recovered in oil stripper working under vacuum.
In this plant, all extraction operations are carried out in closed equipment’s working under vacuum to avoid any solvent loss by evaporation. Air entrapping with the system along with solvent is passed through recuperation system where solvent traces from outgoing vent gases vapors are recovered by absorbing the solvent in absorbing liquid. Hexane from solvent absorbent is recovered by heating the mixture and condensing solvent. This solvent free absorbent oil is again used for recuperation/recirculation.