Waste Engine Oil Regeneration and Utilization

Waste engine oil can be fully utilized through regeneration, which saves energy and protects the environment. The regeneration principle is as follows: taking advantage of the immiscibility of oil and water and the fact that water has a lower boiling point than engine oil, water is separated by heating and standing; concentrated sulfuric acid is used for its oxidizing property to remove organic matter; activated clay is used to adsorb pigments, and mechanical impurities are then removed by filtration. The specific operation process is as follows. Dehydration: Collect the waste engine oil in an oil collection pool. After dehydration, place it in a refining pot and raise the temperature to 70°C–80°C, then stop heating. Let it stand for 24 hours and drain off all free water. Then slowly raise the temperature to 120°C to evaporate the water. After about two hours, once the oil no longer surges, the process is complete. Acid washing: After the oil cools to room temperature, slowly add sulfuric acid while stirring. After the acid addition is complete, continue stirring for half an hour, then let it stand for 12 hours and drain off all acid sludge. Alkali washing: Raise the temperature of the acid-washed engine oil to 80°C, add soda ash while stirring, stir evenly, and let it stand for 1 hour. When test paper shows that the oil is neutral, let it stand for more than 4 hours and drain off all alkali sludge. Activated clay adsorption: Raise the oil temperature to 120°C–140°C, stir at constant temperature, add activated clay, continue stirring for half an hour, then let it stand overnight at a constant temperature of 110°C–120°C, and filter while hot the next day. Filtration: Use an oil filter to obtain regenerated engine oil; if no oil filter is available, the bag hanging filtration method may also be used. During operation, adjustments should be made flexibly according to actual conditions: if the impurities and water content are very low, the first step (dehydration) may be omitted; if the oil color is already normal after acid and alkali treatment, there is no need to use activated clay for decolorization and adsorption.