Catalytic reforming

Catalytic reforming is a process whereby light petroleum distillates (naphthas) are contacted with a platinum-containing catalyst at elevated temperatures and hydrogen pressures ranging from 345 to 3,450 kPa (50–500 psig) for the purpose of raising the octane number of the hydrocarbon feed stream. The low octane, paraffin-rich naphtha feed is converted to a high-octane liquid product that is rich in aromatic compounds. Hydrogen and other light hydrocarbons are also produced as reaction by-products. In addition to the use of reformate as a blending component of motor fuels, it is also a primary source of aromatics used in the petrochemical industry (1).

The need to upgrade naphthas was recognized early in the 20th century. Thermal processes were used first but catalytic processes introduced in the 1940s offered better yields and higher octanes. The first catalysts were based on supported molybdenum oxide, but were soon replaced by platinum catalysts. The first platinum-based reforming process, UOP’s Platforming⁻ process, came on-stream in 1949. Since the first Platforming unitwas commercialized, innovations and advances have been made continuously, including parameter optimization, catalyst formulation, equipment design, and maximization of reformate and hydrogen yields. The need to increase yields and octane led to lower pressure, higher severity operations. This also resulted in increased catalyst coking and faster deactivation rates.

The first catalytic reforming units were designed as semiregenerative (SR), or fixedbed units, using Pt/alumina catalysts. Semiregenerative reforming units are periodically shut down for catalyst regeneration. This involves burning off coke and reconditioning the catalyst’s active metals. To minimize catalyst deactivation, these unitswere operated at high pressures in the range of 2,760 to 3,450 kPa (400–500 psig). High hydrogen pressure decreases coking and deactivation rates.