STRATEGIES FOR VEHICLE WASTE- OIL MANAGEMENT IN PAKISTAN

Abstract

Automotive lubricating oils play a most vital role in our great complex civilization. To estimate the importance of its role one need only consider that every moving part of every machine is subjected to friction and wear. Friction consumes energy; wear causes changes in dimensions and eventual breakdown of the machine. To overcome this problem, lubricating oil is used to reduce friction, protect against wear, carry away heat, protect against rust and remove contaminants from the engine. This lubricating oil is made from crude oil after refining by introducing proper additives and its sources and reserves are limited and are not inexhaustible throughout the world. The used oil loses its effectiveness during operation due to the presence of contaminants. This oil is less subject to biodegradation and does not evaporate but becomes contaminated with substances that are hazardous to human health and the nvironment, so before it can discharged to the environment this oil requires suitable collection and treatment. Therefore to avoid adverse impacts, proper management of waste oil is needed. In this study, waste oil disposal practice in Pakistan has been identified as has the adverse environmental impact associated with it and waste oil management options are discussed in relation to proposed re-cycling options considering the prevailing market price of the new virgin oil. 12 re-generation locations have been identified all over Pakistan to create job opportunities for local people and also reduce transport costs. This study was carried out to evaluate the performance of different methods used to upgrade the waste lube oil into a usable product. Acid/ clay treatment was conducted at laboratory and small pilot scale using the sulfuric acid with different catalysts (Dimethyl Sulfoxide, Dimethyl Formamide and Zeolite) and waste oil ratios. The performance was evaluated against the properties of regenerated oil to the standard base oil, 500N and 150N, and it was found that regenerated oil does not match to standard base oil. In the solvent-extraction process, the performance was evaluated using single and composite solvents with catalysts at laboratory and pilot scale level. The two dependent variables, namely the Percentage of oil loss (POL) and Percentage of Sludge Removal (PSR) were examined as the key parameters in assessing the performance of the extraction process. The solvents used were (70% of 2-propanol and 30% of n-hexane) with addition of KOH, composite solvents (40% 2-propanol, 35% 1-butanol and 25% butanone) and (25% 2-propanol, 37% 1-butanol and 38% butanone) at different solvent-oil ratio and operating variables. In view of the practically and commercial aspect of the project, the used oil recycling process was consecutively run for three or four times at each composition. The physical properties of recovered/re-generated base oil were analyzed and compared. The results from the experimental work shows the laboratory and pilot scale operation revealed similar trends with a little higher performance from the pilot scale operation. This is due to the mechanical mixing of acid-oil/ solvent-oil, coagulants, activated earth clay and controlled heating (dehydration & distillation) extraction of light hydrocarbons and solvents. The properties of re-generated oil were matched to the standard base oil, 500N and 150N, the properties of solvent–oil ratio (25% 2-propanol, 37% Butanol and 38% Butanone) at SOR 6:1 was observed to be the most appropriate solvent composition and achieved about 68% oil recovery and the oil properties compared favorably to graded virgin oil and can be used for similar purposes. Since the quality of regenerated oil matched the virgin oil, it would reduce our dependency on imported oil, save foreign exchange, reduce adverse environment impact and help to preserve oil sources.