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In 1911, the Russian chemist Zelinsky was the first to discover the basic reactions of catalytic reforming. Catalytic reforming is the process in which the molecular structures of hydrocarbons in straight-run gasoline fractions are rearranged into new molecular structures in the presence of a catalyst. Catalytic reforming is divided into platinum reforming, platinum-rhodium reforming, and multimetallic reforming depending on the type of catalyst used. During catalytic reforming, reactions such as naphthenes dehydrogenation and alkane cyclodehydrogenation to form aromatics occur, while reactions like alkane isomerization and hydrocracking also take place. The reforming products mainly consist of aromatics and isoparaffins, featuring a high octane number as well as extremely low levels of olefins and sulfur. Therefore, catalytic reforming can yield high-octane, clean gasoline blending components. Meanwhile, it is also an important method for producing light aromatics such as benzene, toluene, and xylene, along with hydrogen. 1. Molybdenum (chromium) reforming: The first catalytic reforming unit was put into operation in the United States in 1940, using MnO3/Al2O3 or Cr2O3 catalysts. The reforming reaction is carried out in a fixed-bed reactor at temperatures of 480–530°C and pressures of 1.0–2.0 Mpa (H2 pressure). Depending on the catalyst used, it becomes molybdenum reforming or chromium reforming, also known as hydroreforming. This process can produce high-octane gasoline. The advantage of this process is that the gasoline yield is significantly higher than that of thermal reforming, and its stability is also improved. The disadvantages of molybdenum (chromium) reforming are its relatively low catalyst activity and aromatization selectivity; the rapid formation of carbon deposits leads to poor stability of the catalyst, resulting in short operation cycles. Catalyst coking regeneration is required after 4–12 hours of reaction, the processing capacity is limited, and the operating costs are high. The yield of gasoline obtained and its octane rating remain low. Therefore, after World War II, the development of molybdenum (chromium) reforming ceased. 2. Regenerative and semi-regenerative platinum (rhenium) reforming: In 1949, the American company UOP developed a reforming catalyst containing the precious metal platinum (Pt/Al2O3). The invention of the Pt/Al2O3 reforming catalyst ushered in a new era for catalytic reforming. This catalyst exhibits high activity (more than ten times higher than that of the MnO3/Al2O3 catalyst, and over 100 times higher than that of the Cr2O3 catalyst). The reaction takes place under milder conditions, with good selectivity and a high yield of liquid products. The rate of carbon deposition on the catalyst’s surface is low, ensuring good stability; as a result, it can operate continuously for periods of six months to a year without the need for regeneration. This led to significant development of the Pt/Al2O3 catalyst in the 1950s and 1960s, which quickly replaced catalysts containing molybdenum and chromium oxides. To increase the octane number of gasoline and the aromatic yield, it is necessary to raise the operating severity of catalytic reforming units; this leads to an increased rate of carbon deposition on the catalysts, resulting in a rapid decline in their activity. To resolve this contradiction, fixed-bed regenerative platinum reforming (with 4–5 reactors being regenerated in turn) and semi-regenerative platinum reforming (with 4–5 reactors being regenerated in turn) were developed. In 1967, the American company Chevron successfully developed a Pt-Re/Al2O3 bimetallic reforming catalyst, named RHENIFORMING. It is claimed that catalyst reforming has entered a new stage of development. The Pt-Re/Al2O3 bimetallic reforming catalyst not only exhibits improved activity and a significant increase in selectivity, but more importantly, its stability is greatly enhanced compared to the Pt/Al2O3 catalyst. This allows the reforming unit to operate for extended periods at lower pressures (1.5–2.0 MPa), results in a substantial improvement in the selectivity for hydrocarbon aromatization, and it has rapidly replaced the Pt/Al2O3 catalyst. Over the years, various bimetallic (multimetallic) reforming catalysts have been developed by different countries, such as the Pt-Re, Pt-Sn, Pt-Ge series of catalysts. 3. Compared with traditional semi-regenerative catalytic reforming, continuous reforming allows the catalyst in the reactor to be sent to the regenerator for regeneration without shutting down the process. Currently, the two major representative processes for continuous reforming in the world are the CCR Platforming process developed by UOP in the United States, and the Octanizing process developed by IFP in France. 4. The development of catalytic reforming in China: In 1967, China’s first industrial catalytic reforming unit was built and put into operation in Daqing. After the 1970s, China successively developed bimetallic reforming catalysts such as 3741, 3752, and CB-4. In the 1980s, the Research Institute of Petroleum and Petrochemical Technology (RIPP) in China and the Fushun Research Institute of Petroleum and Petrochemical Technology developed the CB-5, CB-6, CB-7, CB-8 platinum-rhodium bimetallic catalysts, as well as the PS-Ⅵ platinum-tin series of catalysts. In 1986, the first industrial scale-up of continuous reforming catalysis 3861 was successfully carried out in our country. In 1994, the GCR-10 catalyst was put into industrial use in the continuous reforming unit equipped with UOP technology at Sinopec Guangzhou Petrochemical Complex. Developed by RIPP and industrially produced by Sinopec Changling Branch, the PS-Ⅶ type continuous reforming catalyst features a high platinum content, a high Sn/Pt ratio, a high specific surface area, and a two-step impregnation process; it also includes A\B additives, which grant it high selectivity, low carbon deposition, and excellent stability. In June 2001, the 500 kt/a low-pressure mixed-bed reforming unit at Sinopec Changling Refining & Chemical Company was successfully commissioned in a single attempt.