An alternate acid cleaning process for the regeneration of waste engine oil and a proposed procedure for the disposal of produced sludge

Abstract

In Pakistan most of the used motor oil cleaning businesses is carried out in processing containers. They do the simple heating and after that a concentrated sulphuric acid is slowly mixed at a room temperature for the removal of the oxidized carbonized substances and other dirt stuff. This study is an attempt to propose an alternate relatively cleaner methodology for the cleaning of used lubricating oil. Briefly, the spent oil was heated till the knocking sound disappeared or in other words the water is fist removed. After that at a room temperature the dehydrated oil was treated with the glacial acetic acid (instead of sulphuric acid) for an hour. A settling time of 24 hours is provided after which reddish brownish (top) and black (bottom) layers were formed. The collected upper layer was then treated with fuller earth (Multani meti) under continuous stirring. Finally, after cooling to a room temperature the oil was filtered to a reasonably regenerated lubricating oil. This cleaning process recovers about 53% v/v of the lubricating oil. The remaining sludge containing the acetic acid is a biodegradable mixture. Moreover, the sludge of the acid treatment can be mixed with cement to prepare concrete blocks.