The Deacidification And Oxidation Stability Study On Regenerating The Waste Internal Combustion Engine Oil To The Base Oil

Engine lubricating oil take up very large proportion in lubricating oil, and the changefrequency of car lubricating oil is very high, so it will produce a lot of waste engine oil. Inrecent years, car ownership in China increased quickly. Suppose each car replacing 5 litersengine oil every year, the annual waste lubricating oil will get to 270 million liters in China.If not properly recycled and reused, it will harm the environment seriously.This thesis mainly using waste internal combustion engine oil as the research object,deacidification of the used lubricating oil is investigated theoretical and experimental．Takethe deacidification rate as standard; respectively use inorganic alkali, ethanol amine, andorganic amine to take off the acid in the waste internal combustion engine oil. At last, theorganic amine was selected to remove the naphthenic acid and optimal condition ofdeacidification was decided. The results indicated the best technological conditions: thereaction time is 3h，the ratio of solvent to oil is 1:3，reaction temperature is 160℃，the stirringspeed is 300r/min. In this process conditions, the removal effect reached 94.36％andTAN(total acid number)is lower than 0.03mg KOH/g．After the deacidification treatment, the acid value of the waste internal combustionengine oil was improved greatly, but the nitrogen content without any change, and the coloris still deep, oxidation stability also is bad, so it is necessary to use clay refining after thedeacidification treatment. Clay refining can improve the oxidation stability and the color ofthe lubricating oil. The experimental results show that the clay refining has obvious effect onthe denitrification of the internal combustion engine oil. The best clay refining process is:clay content 5%, reaction temperature 130℃, reaction time 25 min. In this process conditions,alkaline nitrogen content down to 15.60ppm, denitrification rate reached to 77.46%, colornumber is 17. Use this clay refining process on the up three deacidification oil, alkalinenitrogen content respectively reduced from the 69.209ppm, 69.209ppm, 109.802ppm to7.840ppm, 11.224ppm, 21.705ppm. After twice clay refining, the color of the oil also beimproved obviously, from number 19 fall to number 11.