Naphtha reforming using bifunctional

Catalytic processes frequently require more than a single chemical function, and these bifunctional or polyfunctional materials innst be prepared in away to assure effective communication among the various constitnents. For example, naphtha reforming requires both an acidic function for isomerization and alkylation and a hydrogenation function for aromati-zation and saturation. The acidic function is often a promoted porous metal oxide (e.g., alumina) with a noble metal (e.g., platinum) deposited on its surface to provide the hydrogenation sites. To avoid separation problems, it is not unusual to attach homogeneous catalysts and even enzymes to solid surfaces for use in flow reactors. Although this technique works well in some environmental catalytic systems, such attachment sometimes modifies the catalytic specifici-... 

A separate problem arises when the surface of the support bears non-metallic active centres. Such bifunctional catalysts are widely used in naphtha reforming and it has been suggested that a bifunctional mechanism may also operate in syngas reactions [35]. 

In the naphtha reforming process, a bifunctional metal-acid catalyst is used. During the coinnercial operation, coke is deposited on both catalytic functions producing their deactivation (refs, 1-3). When activity and selectivity are decreased to values where the operation is not convenient from the economical... 

Study of the Simultaneous Deactivation by Coke and Sulfur of Naphtha Reforming Catalysts using a Bifunctional Test Reaction... 

The objectives of the catalytic reforming of naphtha are to increase the naphtha octane number (petroleum refination) or to produce aromatic hydrocarbons (petrochemistry). Bifunctional catalysts that promote hydrocarbon dehydrogenation, isomerization, cracking and dehydrocyclization are used to accomplish such purposes. Together with these reactions, a carbon deposition which deactivates the catalyst takes place. This deactivation limits the industrial operation to a time which depends on the operational conditions. As this time may be very long, to study catalyst stability in laboratory, accelerated deactivation tests are required. The knowledge of the influence of operational conditions on coke deposition and on its nature, may help in the efforts to avoid its formation. 

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