Reforming naphthas

The localization, nature and structure of coke deposits have been examined with electron microscopy. In some cases, such as reforming catalysts, there are few papers where the use of electron microscopy has been reported In other processes, such as in those cases where carbon whistles are formed, there is a large number of studies using this technique. In this case, the morphology of the carbon deposits are easily distinguished from the catalyst, and the interpretation of the analysis is easier than in other cases where coke is distributed on the surface of the catalyst e.g. naphtha reforming catalysts). 

Typically, the electron microscopy alone does not provide much information, and is generally used in combination with related spectroscopies. 

Numerous studies were devoted to the use of bimetallic catalysts, promoted either by an active metal such as rhenium or iridium, or an inactive one such as tin or germanium. These different catalysts were generally prepared by co-impregnation or successive impregnations. Moreover, most of the catalysts prepared by redox reactions were only evaluated in model reactions. For example, Corro et al. [87] prepared Pt-Sn/Al203-Cl catalysts by catalytic reduction or co-impregnation and compared their resistance to coking under cyclopentane feed. Thus, catalysts prepared by the surface redox reaction were less sensitive than the others to deactivation. This result was explained in terms of a more effective interaction between 

Margitfalvi, S. Szabo, F. Nagy, Stud. Surf. Sd. Catal, 1986, 27, 373-409. 

Barbier, Catalytica Studies Division, Advances in Catalysts Preparation, study number 4191 CP, 1992. 

Barbier, in Handbook of Heterogeneous Catalysis, Vol.l, G. Ertl, H. Knozinger, J. Wertkamp (Eds.) Wiley-VCH, Weinheim, 1997, pp. 257-264. 

Bodnar, T. Mallat. I. Bakos, S. Szabo, Z. Zsoldos, Z. Schay, Appl. Catal. A, 1993, 102,105-123. 

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We cite isomerization of Cs-Ce paraffinic cuts, aliphatic alkylation making isoparaffinic gasoline from C3-C5 olefins and isobutane, and etherification of C4-C5 olefins with the C1-C2 alcohols. This type of refinery can need more hydrogen than is available from naphtha reforming. Flexibility is greatly improved over the simple conventional refinery. Nonetheless some products are not eliminated, for example, the heavy fuel of marginal quality, and the conversion product qualities may not be adequate, even after severe treatment, to meet certain specifications such as the gasoline octane number, diesel cetane number, and allowable levels of certain components. 

Some of ihe carbon monoxide and hydrogen produced in ihe steam-naphtha reforming process react to form methane ... 

Capital costs which foUow the same trend as energy consumption, can be about 1.5 to 2.0 times for partial oxidation and coal gasification, respectively, that for natural gas reforming (41). A naphtha reforming plant would cost about 15—20% more than one based on natural gas because of the requirement for hydrotreatiag faciUties and a larger front-end needed for carbon dioxide removal. 

Most catalyst supports are simply nearly inert platforms that help stabilize the dispersion of the catalyticaHy active phase. Sometimes, however, the supports play a direct catalytic role, as exemplified by the alumina used in supported Pt and RePt catalysts for naphtha reforming. 

The previous example was a rather unique application and not a typical case for fluidization. Although some fluidized bed reactions are executed at elevated pressure, like the naphtha reforming, most are used at atmospheric or at low pressures. The proceeding conceptual sketch. Figure 8.2.4, gives the most important features of a fluid-bed, cataljdic reactor. 

A combination unit is a special type of unit that was developed to reduce the investment for a small refinery. In effect, one main distillation unit serves as a crude fi-actionator as well as the cat unit primary fractionator. This same tower also serves the naphtha reformer and visbreaker. A schematic diagram of a combination unit is shown in Figure 2. Crude oil is topped (material boiling below 650°F is removed) in the atmospheric tower, and the topped crude is sent to the combination tower along with cat products and naphtha reformer products. These latter streams provide heat to distill the topped crude and also, being more volatile than topped crude, provide a lifting effect which assists in vaporizing more of the crude. 

Catalytic Naphtha Reforming Science and Technology, edited by... 

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-... 

Liquid feedstocks for olefin production are light naphtha, full range naphtha, reformer raffinate, atmospheric gas oil, vacuum gas oil, residues, and crude oils. The ratio of olefins produced from steam cracking of these feeds depends mainly on the feed type and, to a lesser extent, on the operation variables. For example, steam cracking light naphtha produces about twice the amount of ethylene obtained from steam cracking vacuum gas oil under nearly similar conditions. Liquid feeds are usually... 

In the petroleum refining industry, hydrogen is essentially obtained from catalytic naphtha reforming, where it is a coproduct with reformed gasoline. 

Supported bimetallic catalysts find many industrial applications. Examples include Pt and Rh in automobile exhaust conversion catalysts and Pt and Re (or Pt and Sn or Pt and Ir) in naphtha reforming catalysts. 

Catalytic Naphtha Reforming Science and Technology, edited by George J. Antos, Abdullah M. Aitani, and Jos6 M. Parera... 

X. H. Ren, M. Bertmer, H. Kuhn, S. Stapf, D. E. Demco, B. Blumich, C. Kem, A. Jess 2002, ( H, 13C and 129Xe NMR study of changing pore size and tortuosity during deactivation and decoking of a naphtha reforming catalyst), NATO Sci. Ser. ITMath., Phys. Chem. 7b, 603. 

Butanol over Naphtha Reforming Type Catalysts in Conventional and High Throughput Slurry Phase Reactors... 

In this study butyl acetate (AcOBu) was hydrogenolysed to butanol over alumina supported Pt, Re, RePt and Re modified SnPt naphtha reforming catalysts both in a conventional autoclave and a high throughput (HT) slurry phase reactor system (AMTEC SPR 16). The oxide precursors of catalysts were characterized by Temperature-Programmed Reduction (TPR). The aim of this work was to study the role and efficiency of Sn and Re in the activation of the carbonyl group of esters. 

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