ABSTRACT
This chapter discusses in detail lube base stock (LOBS) or base oil as sometimes called. Here, all physico-chemical properties of the base oil have been defined along with the significance of all these properties along with chemical compositions of various grades of base oils. Based on various applications of base oils, base oils have been classified in different classes and standardized internationally with respect to physico-chemical properties which have been discussed here in detail. To achieve all the desired properties and to produce base oils of different classes and standards, petroleum crude oils having requisite properties and compositions are selected, and the distillates obtained from atmospheric distillation of these crude oils are subsequently processed in vacuum distillation unit followed by furfural extraction/NMP extraction unit, solvent dewaxing unit and finally hydro-finishing unit to get the final product, base oil, to achieve all the desired properties. These processes are basically physical separation processes and the base oils obtained have certain limitation to use them in modern developed machines. Now-a-days, crude oils even not having the requisite properties can be processed to produce base oil, like the vacuum distillates as mentioned above or raffinates obtained from furfural or NMP extraction unit are processed in catalytic dewaxing unit (instead of processing in solvent dewaxing unit plus hydro-finishing unit) where it ensures chemical conversion of the feedstock to achieve all desired properties of base oil, that too, to meet requirement of modern developed machines. Manufacturing processes through all the above units have been discussed in detail along with applications of base oils in this chapter.
