Lubricating Oils

Most lubricants used in variety / quantity are liquids. Water is natural lubricant but has extremely limited application due to very low viscosity, very low boiling point and water causes rusting/ corrosion. Vegetable oils have excellent lubrication property but also have many limitations like very poor oxidation stability, high pour point rapid thickening and may even give foul smell after some operation. Vegetable oils like Castor Oils were used on very large scale till 1925 or so. Vegetable oils are still used directly or as an additive in some applications. Most of the liquid lubricants used at present all over the world are mineral oils, which are petroleum-based oils. These are very complex mixture of variety of hydrocarbons having desired lubrication properties segregated from other hydrocarbons through various processes to remove undesired hydrocarbons like aromatics, olefins, waxes, mercaptans asphaltenes etc. Thus the process is by removing undesired hydrocarbons.