The method of Solvent Extraction is widely using in production of vegetable oil, biodiesel processing, etc. The solvent vapor coming out of the first and second evaporators flows directly into the circulating solvent tank after being cooled by the condenser because it contains no water.

Firstly, the mixed steam from the stripper and steam dryer enters the condenser, the mixed liquid formed by the condensed solvent and water flows into the water separator for water separation. Then the separated solvent flows into the circulating solvent tank, and the water enters the water sealing pool and then discharged into the sewer. If the water discharged from the water separator contains solvent, it enters the cooking tank to evaporate the trace solvent in the water. After condensation, the condensate enters the water separator, and the waste water enters the water sealing pool.

Recover the solvent from wastewater. The waste water discharged from the sub-tank are treated by the water sealing tank. However, when a large amount of dregs is mixed in the water, part of the wastewater in an emulsified state should be sent to the wastewater cooking tank and heated to a temperature above 92 °C by steam, but not more than 98 °C. Evaporate the solvent contained in the water, and then recovered the solvent through a condenser.