Waste Engine Oil Regeneration and Utilization

Waste engine oil can be fully utilized through regeneration, which not only saves energy but also protects the environment. The regeneration principle is to use the characteristics that oil and water are difficult to dissolve in each other and that the boiling point of water is lower than that of engine oil, separating water by heating and standing; using the oxidizing property of concentrated sulfuric acid to remove organic matter; using activated clay to adsorb pigments, and removing mechanical impurities by filtration. The operation process is as follows: Dehydration: Collect the waste engine oil into an oil collection pool. After dehydration, place it in a refining pot, raise the temperature to 70°C–80°C and then stop heating. Let it stand for 24 hours, drain off all free water, then slowly raise the temperature to 120°C to evaporate the water. After about two hours, when the oil no longer churns, this step is complete. Acid washing: Wait until the oil cools to room temperature, then 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 liquid is neutral, let it stand for more than 4 hours, then 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, let it stand at a constant temperature of 110°C–120°C overnight, and filter while hot the next day. Filtration: Use an oil filter to obtain regenerated engine oil. If no oil filter is available, a cloth bag hanging filtration method may also be used. During the operation process, it should be applied flexibly according to actual conditions. If there are very few impurities and little water, the first step (dehydration) can be omitted; if the color of the oil is already normal after acid and alkali treatment, then activated clay decolorization adsorption is not needed.