Catalytic reforming

Catalytic reforming has been a gasoline refining process since its origins in the USA in 1939, but it also plays a significant role in the supply of aromatic hydrocarbons to the petrochemical industry, since the steam cracking of petroleum cuts is the second main route for the production of benzene, toluene and xylenes.

Originally, the aim of catalytic reforming was essentially to transform low-octane petroleum cuts (40-60), commonly known as naphtha, into high-octane fuel bases. As this improvement in index was essentially due to a sharp increase in aromatics content, the process was also considered for the production of aromatics. In this case, a selected gasoline cut was processed under specific conditions, with a view to producing hydrocarbons specifically for the chemical industry.

However, for both economic and technical reasons, this distinction has become blurred. The need for high-performance fuels has grown faster than the need for benzene, toluene and xylenes. The quest for a high octane number (90 to 100), linked to the aromatic content of reformates and the severity of processing, has led to operating conditions and results that are more or less the same for both types of production.

Two more recent events have further accentuated this trend towards higher yields of aromatic compounds. These are the introduction of anti-pollution regulations, in particular to reduce the lead content of gasolines, and the obligation to save energy by making better use of oil cuts. As a result, manufacturers have developed processes that are more specific and better adapted to their constraints:

• for refining, reforming processes operating under severe conditions, with greater operating stability and higher gasoline yields;

• for petrochemicals, techniques that operate at higher temperatures and optimize aromatics production.

This second aspect of catalytic reforming is the only one dealt with here, and the reader is referred to the article Treatment of aromatic gasolines for petrochemical applications. for aromatic hydrocarbon separation techniques.