CHAPTER ONE Introduction
1.1
Background
Lubricating oils or lube oil, as they are commonly called, are viscous liquids used to lubricate moving parts of machineries. Lube oils are mainly a blend of base oil and a number of chemical additives, giving products that last longer and allow the machinery to work better under severe operating conditions. Lube oils are used to protect rubbing surfaces surfaces from friction, wear and excessive excessive heating. They They also provide a protective protective layer on metal metal surfaces to prevent prevent corrosion in addition to providing a tight tight sealing of spaces spaces and engine cleanliness. cleanliness.
During usage the performance of lube oil deteriorates over time. This is due to the contamination of the lube oil with various foreign matters and the degradation of the additives as a result of many physical and chemical interactions (Dennis, 2010). However, after about 5,000 kilometers of engine use, the oil can no longer provide desired functions functions expected of of it. Hence, it is discarded as as used engine oil or waste engine oil.
Used engine oil is known to have adverse impacts on both human health and environment if not managed properly. The presence of degraded additives,
contaminants and by-products of degradation render waste oils more toxic and harmful to human health and the environment than virgin base oils (Irwin 1978) The used oil from one oil change can contaminate 1 million gallons of fresh water —a years’ supply supply for 50 people (US people (US EPA, Used Oil Management Program). For mammals and birds, harmful impacts include toxic contamination, destruction of food resources and habitats and impaired reproductive capability. Report has shown that used oils contain more metals and heavy polycyclic aromatic hydrocarbons (PAHs) that contribute to chronic hazards including carcinogenicity as compared with the fresh oil. Lead (Pb) and Cadmium (Cd) are pollutants associated with high blood levels in Children, anthralgia, anthralgia, colic and other human health effects (Zhang et al 2012).
The main sources of used oils in Nigeria was categorized as; transportation, industry and private electricity generation (Bamiro & Osibanjo, 2004). In Nigeria the estimated used crankcase oil was 150 million liters per annum and industry based used oil was was estimated at at 50 million liters, liters, leading to a total national oil generating capacity of 200 million liters per annum (Bamiro & Osibanjo, 2004). With this figure, efficient technology options for handling, treating and disposing used oil in Nigeria becomes an issue of concern.
In Nigeria there is little or no organized disposal practices (Bamiro & Osibanjo, 2004). Common disposal methods of used oil by auto technician and allied artesian include disposal into gutters, and indiscriminate dumping on land and waterways. Some generators store it in plastic containers like kegs, jerry ca ns and drums, where they are left until use was found for them or they were eventually sold to dealers or direct users. Uses include direct reuse as; lubricants in old and worn engines, weed killer to control weeds, dust control, wood preservation, rust prevention, road construction, construction, etc. etc. Another means of disposal is open burning in in furnaces to generate heat for boilers, cement kilns, bakery oven, etc. These primitive methods methods give rise to toxic air emissions emissions that exacerbate exacerbate air pollution pollution problems.
Used engine oil re-refining is a process that uses conventional refining steps to recover new oil from the used oil by removing water, dirt, heavy metal, and chemical impurities. In re-refining, the used oil is subjected to a complete physical and chemical treatment aimed at recovering the properties of the base oil. In Nigeria, there has has been several studies on the need need for used engine engine oil re-refining, and significant efforts have been made by both the public and private sector in setting up an organized re-refining plant. Key to the success of any re-refining project is the technological technological backup backup of the processes. processes. Hence, the need for for reliable
information on the various technology technology options for the re-refining of used engine oil becomes necessary. necessary.
