Since the Roman era, many liquids, including water, have been used to lubricate mechanical parts that come in contact with one another. This has helped reduce friction, heat, wear, and heat. Because of its broad range of applications, lubricating oils, also known as lube oil, are the most widely used lubricants. There are two main types of lubricant oil: synthetic and mineral. Mineral oils are made from either crude oil or naturally occurring petroleum. Polyalphaolefins are synthetic oils made from hydrocarbon-based polyglycols.
Many types and uses for lube oils, but mineral oils are the most popular. This is due to their low cost. Another advantage of mineral-based lube oils is that they can be produced in a wide range of viscosities–viscosity refers to the substance’s resistance to flow–for diverse applications. Low-viscosity oils contain hydrogen-carbon chains, with molecular masses of approximately 200 atomic mass units (AMU), and high-viscous lubricants with molecular masses as high as 1000 amu. You can mix different viscosities of mineral-based oils to enhance their performance for a particular application. For example, the common 1OW-30 motor oils are a mixture of low viscous and high viscosity oils (for easier starting at low temperatures) and oil that provides better protection for normal operating temperatures.
Synthetic lubricants were first used in aerospace industries. They are often formulated for specific applications to which other oils are unsuitable. Synthetics can be used in extreme operating temperatures or areas where fire resistance is required. This article will be devoted to mineral-based lube oils.
One of the many components of raw petroleum is lubricants. This yellow-to-black liquid mixture contains thousands of hydrocarbons. These organic compounds contain only carbon and hydrogen atoms. The decomposition of small animals and plants that lived around 400 million years ago led to the formation of petroleum deposits. These organisms were affected by changes in climate and geography that occurred in Earth’s history. The breakdowns of these organisms differed from one region to the next.
Due to the differing rates at which organic matter decomposes in different places, the nature of the resulting hydrocarbons and their percentages can vary greatly. The physical and chemical properties of crude oils from different locations vary accordingly. California crude oil has a specific gravity of 0.92 grams/millilitre, while Pennsylvania crude is lighter at 0.81 grams/millilitre. (Specific Gravity is an important aspect of crude oil. It refers to the weight of a substance compared to its volume in water. The specific gravity of crude oil ranges from 0.80 to 0.97 grams per millilitre.
Chemicals called additives can be mixed with the product depending on the application.
Refined oil can be added to it to give oil the desired physical properties. Common additives are metals like lead and metal sulphide. These enhance the oil’s ability to prevent galling or scoring when metal surfaces contact the oil under very high pressures. Another common additive is high-molecular-weight polymerics. They increase viscosity and counteract the tendency for oils to thin at high temperatures. Because they neutralize acids and form protective films upon metal surfaces, nitrosamines can be used as antioxidants or corrosion inhibitors.
Oil is first extracted from crude oil. The oil undergoes a pre-purification process (sedimentation) before being pumped into fractionating stations. A typical high-efficiency fractionating Tower is 25 to 35 feet (7.6-10.6 meters) in size and up to 400ft (122m) high. It is made of high-quality steel to resist the corrosive substances found in crude oils. Inside, there is a condensate collecting tray that ascends in number. The tower houses thousands of crude oil hydrocarbons separated by fractional distillation. The boiling points of each fraction determine how fast the different fractions cool, condense and return to liquid. The boiling point of natural gas is reached first, followed closely by gasoline, kerosene and fuel oil.
- 1 Crude oil is transported by pipeline or tanker ships from the oil well to the refinery. The oil is subject to sedimentation at the refinery to remove any water or solid contaminants (such as sand or rock) that may have been suspended in it. The crude oil is then pumped into large storage tanks to separate from the oil and contaminants.
- 2 The crude oil is then heated to 700 degrees Fahrenheit (371 Celsius). It is now combustible and can be pumped into the first of the two fractionating towers. The hot hydrocarbon vapours rise from this point. They cool and condense, which allows them to be collected in different trays at different tower levels. The tower maintains normal atmospheric pressure so that about 80 per cent of crude oil vaporizes.
- 3 The remaining 20% of oil is then heated and pumped into another tower. Vacuum pressure lowers the boiling point of the residual oil so it can be made to evaporate at a lower temperature. For further processing, the heavier compounds with higher boiling temperatures, such as tar, and inorganic compounds, are left behind.
Soil extraction and filtering
- 4 The lube oil collected in the two fractionating towers has been further processed to remove any unwanted compounds. It is then passed through several ultrafine filters, which remove any remaining impurities. One such contaminant is aromatics. These six-carbon rings can affect the viscosity of the lube oils if they aren’t removed using solvent extraction. Because aromatics dissolve in solvents more than lube oils, solvent extraction is possible. The solvent dissolves the aromatics in the lube oil. Later, once the solvent is gone, it’s possible to recover the aromatics from the oil.
Additives: Inspection and Packaging
- 5. Finally, the oil can be mixed with additives to improve its physical properties (such as resistance to low temperatures). The lube oil goes through quality control tests to determine its viscosity and specific gravity. It also undergoes flash and fire point testing. Once oil meets quality standards, it is packaged and distributed.
Lubricating oils must be nonresinous and have a pale colour, be odourless, and resist oxidation. There are more than a dozen chemical and physical tests to classify and determine the quality of lubricating oil. The most common physical tests measure viscosity, specific gravity, colour, and flash, while chemical tests for fire and light points are more common.
Viscosity is the most important property of all. It refers to lube oils’ resistance to flow at certain temperatures and pressures. In determining the right viscosity of an oil, it is important to consider its application and temperature range. If the oil is too viscous, it will resist metal parts from moving against one another. If the oil is not viscous enough, it will squeeze out the oil between the mating surfaces and not lubricate the surfaces sufficiently. The standard instrument to determine the viscosity for petroleum lubricants is the Saybolt Standard Universal Viscometer. It can be used between 70 and 220 degrees Fahrenheit (21 to 99 degrees Celsius). Saybolt Universal Seconds the measurement of viscosity. This is the time it takes for 50 millilitres of oil to escape from a Saybolt Viscometer cup. It is calibrated through a tube orifice at a specific temperature.
Refinement methods and the type of additives used to make an oil’s specific gravity will determine its ability to resist extreme pressure and low temperatures. The colour of the lube oil indicates how uniform it is for a particular brand or grade. The crude oil’s origin will affect the oil’s fire and flashpoints. The flashpoint is the temperature at which oil must be heated to a temperature that produces enough flammable vapour to cause it to flash when placed in direct contact with light. The fire point is when oil vapour will continue burning when ignited.
The Society of Automotive Engineers (SAE) has established standards for classifying common engine oils. Performance factors include wearing prevention and oil sludge deposits formation.
Mineral-based lubricating oils are limited as the natural resources of petroleum are finite and nonrenewable. Experts have estimated that there are 1.6 trillion barrels of total oil reserves, with only a third being used. As natural oil reserves decrease, synthetic-based oils will likely become more important. This applies not only to lubricating oils but also to other products made from petroleum refining.