Crude oil refinery shows up for many years, that is because crude oils are
complex mixtures of a multitude of–mostly hydrocarbon-type–constituents
with a wide variety of properties, hence they can not be directly used for
industrial or commercial applications. Therefore, crude oils must be treated
in a re?nery by suitable processes to produce an assortment of products
which can be marketed according to certain quality requirements. So it
must use oil refining.
These products are predominantly used as transportation fuels (gasolines,
kerosene, diesel) and for heating purposes(LPG,fuel oils),but also as
feedstocks for the petrochemical industry(naphtha, LPG) and special
manufacturing routes(lubricating oils, greases, bitumen), as well as
specialty products(solvents,wax,coke).All these products consist of
hydrocarbon mixtures. Similarity,  cooking oil refining machine is necessary
to be used.