Study Of The Regeneration Of Waste Lubricating Oil With Solvents

In recent years,with the development of automobile industry,the widespread use of lubricant can lead to large amount of waste lubricating oil.Inappropriate handing methods for used lubricant such as optionally dumping,burning as fuel cause not only environment pollution but also wasting of resources,therefor,it is much significance for recycling use of waste lubricating oil.Traditional acid treatment will be replaced because of equipment corrosion and acid slag difficult to deal with.On the other hand,hydrogenation process has an efficient result of recycling for used lubricant.however,outstanding disadvantages for example,high investment,complex operation hydrogen source limitation and so on are met with.Compared with the traditional regeneration method,the regeneration of waste lubricating oil with solvents is a green,low input with high returns and safe used lubricating oil regeneration technology due to its flexible option,solvent recycling,and environment friendly.Solvent regeneration technology through extraction-flocculation with low polar solvent:alcohol,ketone,etc,removes metal additives out of work and macromolecule impurities to make waste lubricant up to standard.Moreover,it can improve the option effect of weakening tower and heat exchanger coking due to macromolecular sludge impurities during distillation.In this experiment,the waste lubricating oil is from a auto 4S shop in Qingdao,and the main properties of used lubrication oil were analyzed such as viscosity,Viscosity index,carbon residue,acid number,metal elements?Ca,Mg,Zn,Fe?content,flash point and condensation point.During the regeneration experiment of waste lubricants with alcohol and ketone as solvent of extraction-flocculation,the effect of operating factors including solvent species,solvent oil ratio,and sludge separation way on regeneration was studied as well as the composite solvent including isopropyl alcohol.Through the comparison of composite solvent,the composite solvent:isopropyl alcohol-A was the best one,and the effect of A volume fraction of mixed solution,the mass ratio of solvent to oil ratio,refining temperature and refining time on regeneration of waste lubrication oil was investigated.At the same time,the effect of option conditions was researched through orthogonal experiment.The analyzing results of basic properties of used lubrication oil indicated it was out of work.With the research of waste lubricating oil regeneration by the single solvent,alcohol or ketone,of which the carbon number was three,had a weak solubility for used lubricants,while the more number of carbon had a weak polarity force and strong solubility for basic oil.The regeneration processes conditions were as follows:solvent to oil mass ratio 5/1,refining temperature 25?and refining time 20min with stirring.After refining,ash content,carbon residue,the concentration of metal element of additives?Ca,Mg,Zn?and friction element?Fe?were decreased clearly.In order to improve performance of complex solvents for excellent effect of flocculation for impurities,high solubility for basic oil,and high yield of regenerated lubricating oil,the refining effect of complex solvents named as M1,M2,M3 and M4 were in comparison and the results indicated that M4 was a better one.As this study indicated,optimization conditions of the regeneration was obtained by experiments:A volume fraction of mixed solution of 50%,the mass ratio of solvent to oil ratio of 5/1,refining temperature of 35?,refining time of 30 min.Compared to waste lubricants,the metal content of the regenerated lubricating oil nearly decreases to 26.12 ug·g^-1,1.43 ug·g^-1,171.89 ug·g^-1,0.95 ug·g^-11 respectively for Ca,Mg,Zn and Fe reduced by 91.84%,87.95%,88.87%,90.71%.The yield of the regenerated lubricating oil also adds up to 85.5%.Under the optimal process conditions,the quality of the regenerated lubricating oil is dramatically improved and generally reaches the standard of the base oil HIV150.Moreover,the effect of option conditions was researched on yield of regeneration oil,ash content and refractive index through orthogonal experiment.