In general case, crude oil reforming is the process of converting normal and cyclic paraffins in oil to aromatic paraffins. The process occurs at 500-550ºС in the presence of catalysts. Reforming is necessary to improve the quality of low octane gasoline by increasing the amount of aromatic hydrocarbons.
No refinery operates without catalytic reforming. Since most straight run gasolines are low octane, additional processes are required. Reforming allows to produce 80-85% gasoline with octane number of 80-90.
Reforming can be performed also on secondary distillates, such as gasolines from coking, thermal and hydrocracking. The yield of the above fractions is relatively low (15-20%), so the capacity of catalytic cracking units exceeds that of reforming units.
The development of catalytic reforming is stimulated by the demands of the chemical industry for monocyclic aromatic hydrocarbons, which are used in production of synthetic rubber, plastics, detergents etc.
The main reaction of catalytic reforming is hydrogenation of hexavalent naphthenes. Their ability to transform into aromatic hydrocarbons at 300ºС in the presence of nickel and platinum group metals was first discovered in 1911.