The key difference between base oil and crude oil is that base oil is made from refining crude oil, whereas crude oil is an unrefined form of oil that naturally occurs in geological formulations.
Base oil is an oil useful in manufacturing products like lubricating greases, motor oil, and metal processing fluids. Crude oil is a mixture of comparatively volatile liquid hydrocarbon and contains some nitrogen, sulfur, and oxygen.
CONTENTS
1. Overview and Key Difference
2. What is Base Oil
3. What is Crude Oil
4. Base Oil vs Crude Oil in Tabular Form
5. Summary – Base Oil vs Crude Oil
What is Base Oil?
Base oil is an oil useful in manufacturing products like lubricating greases, motor oil, and metal processing fluids. Generally, these different products require different compositions and properties in the oil. The viscosity of the liquid at various temperatures is an important factor regarding base oil. We can determine whether or not a crude oil is suitable to make a base oil by the concentration of the base oil molecules and the easiness of the extraction of these molecules.
There are different types of crude oil used for manufacturing base oils. Among these types, the most common one is paraffinic crude oil. However, there are also naphthenic crude oils that can create products with better solubility and very good properties at low temperatures. We can use hydrogenation technology where sulfur and aromatics are removed using hydrogen under high pressure. We can also obtain pure base oils that are suitable when quality requirements are particularly stringent.
There is an official classification of the American Petroleum Institute with five major groups as follows:
Group I: contains conventional petroleum base oils
Group II: contains petroleum base oils obtained by hydrocracking
Group III: petroleum base oil produced from hydrocracking, hydroisomerization, and hydrotreating
Group IV: contains synthetic oils made of poly-alpha-olefins
Group V: includes naphthenic oils and polyesters
What is Crude Oil?
Crude oil is a mixture of comparatively volatile liquid hydrocarbons and contains some nitrogen, sulfur, and oxygen. Crude oil is commonly known as petroleum. Naturally, it appears as a yellowish-black liquid mixture of hydrocarbons. It can be found in geological formulations. It forms as a fossil fuel made of dead organisms such as zooplankton and algae. These organisms are buried underneath sedimentary rocks and are subjected to both prolonged heat and pressure.
Figure 01: Petroleum Oil
Crude oil contains alkanes, cycloalkanes, and aromatic hydrocarbons. Generally, these compounds have 5 – 40 carbon atoms per molecule. There can be trace amounts of shorter or longer molecules that are present in this mixture.
Figure 02: Some Compounds that Can be Extracted from Crude Oil
Among these hydrocarbon compounds, alkanes, including pentane to octane, are refined into gasoline. From nonane to hexadecane, hydrocarbons are refined into diesel fuel, kerosene, and jet fuel. The alkane compounds having more than16 carbon atoms per molecule are refined to get fuel oil and lubricating oil.
The aromatic hydrocarbon compounds in crude oil are unsaturated hydrocarbon compounds having one or more planar six-carbon rings named benzene rings. These compounds can burn with a sooty flame, and many of them have a sweet aroma. However, some of these compounds are carcinogenic.
What is the Difference Between Base Oil and Crude Oil?
The base oil and crude oil are two important oil types that have many applications in industries. The key difference between base oil and crude oil is that base oil is made from refining crude oil, whereas crude oil is an unrefined form of oil that naturally occurs in geological formulations.
The below infographic presents the differences between base oil and crude oil in tabular form for side-by-side comparison.
Summary – Base Oil vs Crude Oil
Base oil is an oil useful in manufacturing products, including lubricating greases, motor oil, and metal processing fluids, while crude oil is a mixture of comparatively volatile liquid hydrocarbons and contains some nitrogen, sulfur, and oxygen. The key difference between base oil and crude oil is that base oil is made from refining crude oil, whereas crude oil is an unrefined form of oil that naturally occurs in geological formulations.
Reference:
1. “Base Oil Groups Explained.” Machinery Lubrication, Noria Corporation, 9 Oct. 2012.
Image Courtesy:
1. “Petroleum sample” By Nefronus – Own work (CC0) via Commons Wikimedia
2. “Octane molecule 3D model” (Public Domain) via Commons Wikimedia