Dewaxing of lubricant base oils

Most paraffinic crude oils contain a significant amount of wax across the entire lube fraction viscosity range. Since the wax in base oil has a high melting point, as temperatures drop, the wax crystallises and thickens the lubricant until it finally stops flowing. Therefore, dewaxing processes are used during lube refining to remove waxy components from base oils to ensure that lubricants formulated with these base oils will continue to flow at low temperatures. Dewaxing is achieved by cooling the oil to below the crystallisation temperature of its waxes. The crystallised waxes are then removed by filtration. One of the most common dewaxing processes is solvent dewaxing [1]