The Overview of Toxins in Used Lube Oils
1. Lubricant Oils
1.1 Base oil form Petroleum
Modern lubricants are mostly formulated form a wide range of base fluids and different packages of chemical additives.The majority of the base fluids is produced for the recycling of crude oil since large crude oil refining operations can produce base oil with high quality and excellent performance at an economical price.base oil composition may vary depending on the crude oil it is made form.For different applications,lubricants are formulated by blending different base oils and additives to meet a series of performance specifications.Hence,formulations and performance specifications for automotive lubricants,industrial lubricants,aviation lubricants,and marine lubricants are greatly different.
In a modern oil recycling plant,base oil plants(lube plants)are integrated with the mainstream refinery process. Overall production capacity for the lubricant base oil is only a very small part(about 1percent) of the total recycling production lines.
The feedstock for this process is residue form atmospheric distillation,which represent only about 50% of original crude oil in a mainstream refinery process.
1.2 Automotive lube oil
For special performance specifications,automotive lube oil has unique characteristics different for industrial lube oils.The most important responsibility of the automotive lube oil is to form a layer between metal surfaces of various engine parts so that friction and wear is minimized.It also serves as a sealant to fill the microscopic ridges and valleys in any metal surfaces to increase the engine`s efficiency.
Lube oil also acts as coolant in the automatic transmission and engine.It helps to take away the heat form the combustion of fuel as well as form friction.In addition,it serves as a cleaning agent to carry away dirt or other debris that may damage the bearings or other parts that are operated in tight tolerance. Debris is removed through the engine oil filter or transmission filter.The detergent additives in the auto lube oil can combat the combustion by-product.Burning gasoline or diesel fuel produces acids moisture,soda,ash and other contaminants.Hence detergent would fight these by-products and inhibit their buildup as sludge or varnishes.
In order to meet the performance specification as mentioned above, a specific additive package is required to prolong the oil`s life and improve oil protective qualities,the major additives in automotive lube oils are listed as follows:
Detergents: to keep high temperature engine parts clean and free form deposits
Dispersants: to suspend the disperse sludge and varnishes forming materials and prevent them to clog the engine.
Anti-wear: to add film strength to prevent wear of heavily loaded surfaces
Friction modifies: to reduce the friction losses throughout the engine
Corrosion inhibitors:to fight the rust and wear caused by acids and moisture
Oxidation inhibitors:to limit the growth of bubbles and break them up quickly in the oil,allow the oil pump to only circulate oil.not oil and air throughout the engine.
Viscosity index improver:to fight viscosity change with temperature variations
Pour point depressant: to improve the oil`s ability in winter to flow at very low temperature.