Reforming

reforming [¦rē′fȯrm·iŋ]

(chemical engineering)

The thermal or catalytic conversion of petroleum naphtha into more volatile products of higher octane number; represents the total effect of numerous simultaneous reactions, such as cracking, polymerization, dehydrogenation and isomerization.

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Reforming 

an industrial process for refining the gasoline and ligroin, or light naphtha, fractions of petroleum in order to obtain high-octane gasolines and aromatic hydrocarbons. Until the 1930’s, reforming was a type of cracking and was carried out at a temperature of 540° C and pressures of 5-7 meganewtons per square meter (MN/m²), or 50-70 kilograms-force per square centimeter (kgf/cm²). The process yielded gasoline with an octane number of 70-72. In the 1940’s reforming became a catalytic process, whose scientific principles were developed by, among others, N. D. Zelinskii and his followers and V. I. Karzhev and B. L. Moldavskii. This process was first used on an industrial scale in the United States in 1940.

Reforming is carried out at industrial installations equipped with a heating furnace and at least 3-4 reactors at temperatures of 350°-520°C and pressures of 1.5-4 MN/m² (15–40 kgf/cm²) in the presence of various catalysts. The catalysts include platinum, platinum-rhenium alloys, polymetallic catalysts containing platinum, rhenium, iridium, germanium, and certain other metals. In order to avoid impairing the activity of the catalyst by coke, which is a product of cracking-type reactions, reforming is carried out under high pressure with hydrogen, which circulates through the heating furnace and reactors.

Gasoline with an octane number of 90-95 makes up 80-85 percent of the yield from the reforming of petroleum gasoline fractions. Hydrogen accounts for 1.5-2 percent, and the balance is made up of gaseous hydrocarbons. Reforming is very important in the production of such aromatic hydrocarbons as benzene, toluene, and xylenes. Previously, such hydrocarbons had been obtained chiefly from the by-product coke industry. By 1970, however, more than 90 percent of the benzene produced in the United States and Canada was obtained from crude oil.

REFERENCES

Smidovich, E. V. Destruktivnaia pererabotka nefti i gaza, 2nd ed. (Tekhnologiia pererabotki nefti i gaza, part 2.) Moscow, 1968.
Sulimov, A. D. Kataliticheskii riforming benzinov. Moscow, 1973.

E. V. SMIDOVICH