Catalytic reforming, chemistry

C, 0.356—1.069 m H2/L (2000—6000 fU/bbl) of Hquid feed, and a space velocity (wt feed per wt catalyst) of 1—5 h. Operation of reformers at low pressure, high temperature, and low hydrogen recycle rates favors the kinetics and the thermodynamics for aromatics production and reduces operating costs. However, all three of these factors, which tend to increase coking, increase the deactivation rate of the catalyst therefore, operating conditions are a compromise. More detailed treatment of the catalysis and chemistry of catalytic reforming is available (33—35). Typical reformate compositions are shown in Table 6. 

Pollitzer, E. L., Hayes, J. C., and Haensel, V, The Chemistry of Aromatics Production via Catalytic Reforming, Refining Petroleum for Chemicals, Advances in Chemistry Series No. 97, American Chemical Society, 1970, pp. 20-23. 

Zaera F (2002) Selectivity in hydrocarbon catalytic reforming a surface chemistry perspective. Appl Catal A 229 75... 

The characteristics of dehydrogenation coking vary with the chemistry of the catalytic process. Important features are best considered with three important examples (1) catalytic reforming, (2) hydrotreating, and (3)... 

B. C. Gates, J. R. Katzer, G. C. A. Schuit, Chemistry of Catalytic Processes, Chap. 3, McGraw-Hill, New York, 1979. Pt/AljOs and the catalytic reforming process. 

Dehydrogenation is a key reaction in the production of commodity chemicals such as butadiene, styrene and formaldehyde and in the catalytic reforming of petroleum naphtha [1-3], In the fine chemical industry, however, dehydrogenation is used less than the numerous hydrogenation reactions which are available. Dehydrogenation is usually an endothermic reaction which requires high temperatures. For such conditions the chemical stability of many fine chemicals is often insufficient. Most of the dehydrogenation reactions used in fine chemistry yield aromatic or heteroaromatic compounds and aldehydes or ketones. 

While the emphasis in this discussion is on the chemistry of aromatics production from the point of view of product distribution and mechanisms, it is necessary to describe the catalyst used briefly. Until about 20 years ago a number of different catalysts were used for catalytic reforming, including vanadium (126), molybdenum (47), cobalt-molybdenum (159), and chromia (3,41,85,100) catalysts. Since the time when platinum reforming catalysts were introduced to the industry (2, 24, 56,... 

Itoh, N., Xu, W. C., Hara, S., Kakehida, K., Kaneko, Y., Igarashi, A. (2003). Effects of hydrogen removal on the catalytic reforming of n-hexane in a palladium membrane reactor. Industrial and Engineering Chemistry Research, 42, 6576. 

The third chapter deals with the reforming chemistry of conventional and alternative fuels, and with the chemistry of catalytic carbon monoxide clean-up, sulfur removal and catalytic combustion. 

Diehm C Catalytic reforming offuels over noble metal-coated honeycomb monoliths capillary-based in-situ sampling technique, Dissertation (Ph.D. Thesis), 2013, Faculty of Chemistry and Biosciences, Karlsruhe Institute for Technology. 

The chemistry of catalytic reforming includes the reactions listed in Table 18. All are desirable except hydrocracking, which converts valuable Cs-plus molecules into light gases. The conversion of naphthenes to aromatics and the isomerization of normal paraffins provide a huge boost in octane. H2 is produced by dehydrocyclization of paraffins and naphthene dehydrogenation, which are shown in Figure 15. 

In addition, a catalytic version of Tt-allylpalladium chemistry has been devel-oped[6,7]. Formation of the Tr-allylpalladium complexes by the oxidative addition of various allylic compounds to Pd(0) and subsequent reaction of the complex with soft carbon nucleophiles are the basis of catalytic allylation. After the reaction, Pd(0) is reformed, and undergoes oxidative addition to the allylic compounds again, making the reaction catalytic.-In addition to the soft carbon nucleophiles, hard carbon nucleophiles of organometallic compounds of main group metals are allylated with 7r-allylpalladium complexes. The reaction proceeds via transmetallation. These catalytic reactions are treated in this chapter. 

Ni catalysts u g ZrOj as a unique support that seems crucial to minimize coking under reaction conditions applied for CH4/CO2 reforming. For two successfiiUy developed catalysts, (Pt and Ni on Z1O2) the present contribution outlines the sequence of the elementary steps and the catalytic chemistry of the active metal and the support in order to explain catalysts activity and stability. 

Caballero, M. A. Aznar, M. P. Gil, J. Martin, J. A. Frances, E. Corella, J., Commercial steam reforming catalysts to improve biomass gasification with steam-oxygen mixtures. 1. Hot gas upgrading by the catalytic reactor. Industrial and Engineering Chemistry Research 1997,36(12), 5227-5239. 

Czernik, S. French, R. Feik, C. Chomet, Ev Hydrogen by catalytic steam reforming of liquid byproducts from biomass thermoconversion processes, Industrial and Engineering Chemistry Research 2002,41,4209. 

The elements of range in value from 0 to 1 and are the ratio of the reformer kinetic constants at time on stream t to the values at start of cycle. At any time on stream t, the deactivation rate constant matrix K(a) is determined by modifying the start-of-cycle K with a. From the catalytic chemistry, it is known that each reaction class—dehydrogenation, isomerization, ring closure, and cracking—takes place on a different combination of metal and acid sites (see Section II). As the catalyst ages, the catalytic sites deactivate at... 

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