Environmental Engineering

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Browsing Environmental Engineering by Author "Andargachew, Hayalu"

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    Recycling of Used Lubricating Oil Using Acid-Clay Treatment Process
    (Addis Ababa University, 2014-10) Andargachew, Hayalu; Yimam, Abubeker (PhD)
    Numerous industries are emerging in Ethiopia and urban developments are accelerated giving rise to multiple waste generations. As used lubrication oil is one of the hazardous wastes generated at different development sectors, it should not be utilized and/or disposed in ways which are unsafe to the environment hence calling for its proper management. This study primarily focuses on the recycling of used oil by applying acid-clay treatment process. Used engine oil properties gave expected undesired characteristics caused by oil deterioration. The characterization was indicative to the sources of contaminations from conditions during the oils application period. For instance, the lower flash point (132°C) indicated light fuel contamination effect; increased density (0.93 g/ml) and viscosity (kinematic Viscosity @ 40 °C was 126.41 cSt) showed possible oxidation and polymerization products dissolved and suspended in the used oil; and ash content (2.3%) indicated contamination from incombustible solid particles of dirt, dust, grit and metallic fragments. Similarly, deviations of other parameters also referred different contamination sources. Recycling experiments utilized 15, 20 and 25% acid and adsorbent (Bentonite clay) ratios with different combinations. Nine combinations with their respective triplicates were conducted. The experiments showed that the acid-clay treatment process was effective in recovering valuable oil from used oil samples with comparable qualities. From the twenty seven runs performed, yields within the range of 55% to 74.7 % was obtained. The run with acid percentage of 20% and adsorbent percentage of 15% was chosen as the optimum combination using statistical analysis that considered selected quality parameters of recovered oil i.e. density, kinematic viscosity @ 40 °C and ash content. The optimum combination gave a 69% yield; density of 0.886 g/ml; kinematic viscosity @ 40 °C of 94 cSt; and 0.34% ash content. Eight to ten percent of valuable light fuel was also recuperated from the vacuum distillation step of the process. The preliminary cost analysis showed, an estimated sum amount of 22.86 birr is expected to recover a liter of usable oil which is 61.64 birr less, relative to the amount required to import the original fresh oil that costs 84.5 birr/liter.