Acid oil is subjected to hot water washing to remove mineral acidity and water-soluble impurities. Water and oil are mixed in a counter-current direction for effective separation, with decanted oil sent for further processing. Wash water is recovered in the effluent treatment plant after reclaiming any oil carry-over. Oil sludge is separated by gravity and discarded, while the washed oil is dried in a vacuum dryer to remove residual moisture.

Washed and dried oil is treated with phosphoric acid to remove phosphates, gums, trace metals and soaps. Bleaching earth is added to adsorb colour pigments and contaminants. The oil is then passed through a pressure leaf filter to remove spent bleaching earth and further polished through a secondary filter. The entire process is carried out under vacuum in a mechanically agitated bleacher, ensuring maximum contact between oil and bleaching earth.

Free fatty acids are removed using a vacuum heat exchanger, packed column stripper, fatty acid scrubber and retention vessel. Steam stripping in a counter-current flow with preheated oil reduces FFAs to below 0.1%, with structural packing enhancing surface contact for efficient removal. Heat recovery systems minimise energy use by cooling discharged oil with incoming feed. Fatty acid vapours are scrubbed by pre-cooled circulating fatty acids, maintaining process balance and efficiency.

Residual free fatty acids react with glycerine in multiple reactors under high temperature and vacuum. Continuous removal of water shifts the reaction towards triglyceride formation, converting by-products into valuable oil. Heat recovery units pre-heat fatty acids using discharge oil and thermic fluid systems, optimising energy use. Reactor temperatures are carefully controlled to maximise conversion and maintain process stability.