CRUDE OIL TO BASE OIL
The majority of all lubricants used today, currently comprise of conventional (Mineral-Based) oils – Base Oil. Together mixed with additives these create the lubricants we see on the market today.
The process of creating a BASE OIL starts with Crude Oil.
The petroleum that flows from a well in the form of crude oil comes in many varieties and types, ranging from light-colored oils containing mostly small hydrocarbon molecular chains to black, nearly solid asphalt-like large hydrocarbon chains. These crude oils are very complex mixtures containing a range of different compounds made of hydrogen and carbon. These compounds (known as hydrocarbons) can range in size from methane (containing one carbon and four hydrogen atoms) to massive structures with 60 or more carbon atoms. This molecular size distribution can be used to our advantage.
Most lubricating oils come from crude oil. In order to get lubricating oil from a crude oil, the crude oil must be sent through a refinery. The refinery takes from the crude oil a lot of molecules of various sizes and structures that can be used for different things. For example, petrol, diesel and kerosene are all derived from crude oil. Lubricating oil relates to hydrocarbon molecules of a particular size (in the range from 26 to 40 carbons). Fairly large and heavy molecules are needed to work as lubricating oils. The molecules that are used with gasoline and kerosene are smaller and have fewer carbons in the structure of the molecule. The refinery puts these molecules in little silos based on size and weight, and removes impurities, enabling each of the products from the crude oil to be utilized.
After the crude oil is desalted and sent through a furnace where it is heated and partially vaporized, it is sent to a fractionating column. This column operates slightly above atmospheric pressure and separates the hydrocarbons based on their boiling points, which are directly affected by their molecular size. In the fractionating column, heat is applied and concentrated at the bottom. The hydrocarbons entering the column will be vaporized. As they travel upward in the column, they will cool until they condense back into a liquid form. The point at which this condensation occurs varies again based in part on the molecular size.
By pulling the condensing liquid from the column at different heights, you can essentially separate the crude oil based on molecular size. The smallest of the hydrocarbons (5 to 10 carbon atoms) will rise to the very top of the column. They will be processed into products like petrol. Condensing just before reaching the top, the compounds containing 11 to 13 carbon atoms will be processed into kerosene and jet fuel. Larger still at 14 to 25 carbon atoms in the molecular chain, diesel and gas oils are pulled out. The compounds with 26 to 40 carbon atoms are used for the creation of lubricating oil. At the bottom of the column, the heaviest and largest of the hydrocarbons (40-plus carbon atoms) are taken and used in asphaltic-based products.
Check in next week to see how BASE OIL is created and the differences between the different groups of BASE Stock.