Regeneration Of Used Lubricant Oil By Extraction/Flocculation And Clay Refining

The vast majority of components of used lubricant oil are high molecular weightmaterial, they are degraded difficultly in the environment and which may containheavy metals, so if used lubricant oil can’t get appropriate treatment, it will causeenormous harm to the environment. If, on the other hand, used lubricant oil can getappropriate treatment, it can not only protect the environment, still can save energy,especially the situation of shortage of oil resources is more and more obviously.Firstly used lubricant oil is often directly discarded or burned as fuel directly, notonly caused the pollution to the environment, and also caused a waste of energy. Laterthe regeneration process of used lubricant oil was gradually gotten more and moreattention and development. The earliest regeneration process of used lubricant oil issulfuric acid-clay refining process, this process produces a large number of acidresidues hard to handle, which cause severe pollution to the environment. Nowseveral mature regeneration process of used lubricant oil has been created, whichcause little or no pollution to environment. In view of the present situation of usedlubricant oil regeneration industry, a regeneration process of used lubricant oil wasresearched in this paper.In view of the recycling engine lube oil which was collected from a motor repairshop in Guangzhou, through the thermal settlement, extraction/flocculation and clayrefining to get lubricant base oil. In the thermal settlement section, the effect ofsettlement time to the regeneration oil was investigated and the best thermalsubsidence time was19h. In the extraction/flocculation section, we chose a mixture oftwo alcohols as solvent, inspected the solvent ratio (V/V), extraction temperature,extraction time, the change of volume of solvent/quality of used lubricating oil, theaddition amount of KOH and settlement time after extraction’s influence on theperformance of regeneration oil. The best extraction/flocculation conditions were asfollows: V(Isopropyl alcohol)/V(n-butyl alcohol)=3/1, extraction temperature60℃，extraction time30min, V(solvent)/M(oil)=5/1. After extraction/flocculation process,most of additives, colloid and asphalt were removed from used oil. In the clay refining experiment part, the refining temperature, the amount of clayand refining time’s influence on yield and performance of regeneration oil werediscussed. The best clay refining conditions were as follows: refining temperature300℃，refining time15min, clay to oil ration10wt%. After clay refining, viscosity,viscosity index, low-freezing, acid value, ash content, water content and mechanicalimpurities content of regeneration oil conforms to requirements of lubricant base oilof brand100, the regeneration oil can be used as lubricant base oil. The flocculationwas produced during the extraction/flocculation process and the clay residue producedin the clay refining can be burned with other fuel in a boiler which has perfect flue gascleaning system, it can be no pollution to environment. In the whole process, there isno acid or alkali substances added to oil, therefore the corrosion caused by theflocculation produced during extraction/flocculation process or residue of clay to theboiler was very small.