Base oil
Before lubricant is blended with additives, it constitutes of just the base oil; in case of grease, the base oil is blended with a thickener. Base oils for industrial lubricants belong to two different categories – synthetics and mineral oil, and they are present in all lubricants. Selecting the ideal base oil for any given application is a critical decision. So it is important to understand the complexity of your base oil formulations to avoid any confusion in selecting them. This article will provide you with all the information you need for selecting your base oil.
Groups of Base Oil
Group 1, 2 and 3 are all mineral oils, with chronologically increasing refining process severity. Base oils under Group 1 are made using solvent-refining or solvent-extraction technology.
Base oils under Group 2 are produced by hydrotreating or hydrogenation. It is a process that uses hydrogen gas to refine oils, but they are better for converting components like aromatics that are undesirable, into hydrocarbon structures that are desirable.
Base oils in Group 3 are produced in a similar fashion as Group 2, the only difference is that the process of hydrogenation or hydrotreating in group 3 is coupled with high pressures and high temperatures. This leads to convert all the undesirable components in the oil into desirable hydrocarbon structures.
Group 4 contains only one type of synthetic oil called polyalphaolefin (PAO), these synthetically created hydrocarbons are the most widely used base oils form the synthetic category. They are created using the polymerization process that gives an olefinic tail by the introduction of ethylene gas. This process makes the chemical structure of PAOs quite similar to that of highly refined mineral oils form Group 3. While PAOs lack in lubricity, additive solubility, film strength and seal shrinkage, they have powerful advantages such as superior oxidation stability, higher viscosity index, lower volatility and excellent performance in high and low temperatures. POWs are employed widely for lubrication; they are especially preferred when the equipment is expected to reach higher temperatures.
Group 5 contains all the remaining oil bases which are mostly synthetics. Most common oils that belong to this group are polyolesters, diesters, polyalkylene glycols, silicones and, phosphate esters.
Selecting Base Oil
Choosing a base oil requires you to make tradeoffs for the lubrication properties you require for the required application. Consider viscosity for example – when it is high you get strong film strength and when it’s low you get optimal energy consumption and low-temperature fluidity. You may in some cases prefer to have a balance between these properties to avoid compromising on either side.
It is very important to understand the base oil options available to you and their respective advantages and disadvantages. Selecting justifiably more expensive base oil is always better than risking an equipment failure. Always optimize your base oil selection to minimize the risk of equipment failure.
Sources of Base Oil
Industrial lubricants are categorized depending on the type of base oil they contain; the most prominent ones are:
- Mineral oil – This type of oil is refined from crude oil and its quality depends on the quality of the process used for refining the material.
- Synthetic oil – Synthetic oils get unique properties that are required for their intended purpose through man-made synthesizing processes
- Vegetable oils – Few lubricants that are utilized for renewable and environmental purposes belong to this category. They are derived from plant oils.
