Refining of Used Motor Oil Using Solvent Extraction

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Addis Ababa University


Used lubricating motor oil is a high pollutant material that requires responsible management. It may cause damage to the environment when dumped into the ground or into water streams including sewers. This may result in groundwater and soil contamination. Recycling of such contaminated materials will be beneficial in reducing lubricating motor oil costs. In addition, it will have a significant positive impact on the environment. Used oil can be refined to yield base oils that are blended into lubricating products, thus reducing the consumption of virgin oils. Refining restores the physical and chemical properties of lubricating oil so that it can go back to its original and intended use. This thesis work investigates refining of used lubricating motor oil using solvent extraction method. The laboratory experiment was based on a full factorial design and two categorical factors with two levels were nominated which were solvent to used oil ratio (4:1&6:1) and solvent type (2-Propanol and n-Butanol). First used lubricating motor oil, of two varieties, namely TOTAL Rubia and TOTAL Quartz was collected from TOTAL Ethiopia oil company gas stations and characterized for important properties and contaminates. Then by applying appropriate treatment, i.e. pretreating, dehydration, vacuum distillation, solvent extraction and distillation for solvent recovery, the base oil was obtained. The refined base oil was then characterized and compared with the used and virgin oil. The type of solvent used and the mixing ratio applied for different runs has shown significant effects on the yield of recovered oil. 2-Propanol solvent with mixing ratio of 6:1 gave the best result. A Maximum yield of 72% was obtained for Rubia Tir 7400 using 2-Propanol solvent and mixing ratio of 6:1, whereas minimum recovery yield of 55% was obtained using n-Butanol and 4:1 mixing ratio. For Quartz 20W-50 a maximum yield of 73.4 was obtained using 2-Propanol solvent and mixing ratio of 6:1 whereas minimum recovery yield of 50% was obtained using n-Butanol and 4:1 mixing ratio. The metal contaminants and chlorine are considerably reduced in the base oils for both lubricants. So it can be concluded that used lubricating motor oil can be refined using solvent extraction method and reduces environmental contaminations and decreases foreign currency



process Engineering