Modern state of the catalytic reforming of petrol fractions. Experience of manufacture and industrial exploitation of reforming catalysts of the PR series

Analysis of the modern state of catalytic reforming is performed. Comparative assessment of the efficiency of various technologies of the process is given and their distribution in Russia and abroad is shown. Experience of the modernization of reforming installations with periodic catalyst regeneration is summarized. The state of manufacture of reforming catalysts in our country and accumulated experience of the development of catalysts of the PR series are presented. Results of industrial exploitation of new domestic reforming catalysts are shown. On this basis comparative assessment of Russian and imported catalysts is given. Original Russian Text D.I. Kiryanov, M.D. Smolikov, V.V. Pashkov, A.G. Proskura, E.V. Zatolokina, I.E. Udras, A.S. Belyi, 2007, published in Russkii Khimicheskii Zhurnal, 2007, Vol. 51, No. 4, pp. 60–68.     

The Effect of Support Nature and the Temperature of Preliminary Calcination on the Atomic Catalytic Activity of Supported Palladium Catalysts for the Complete Oxidation of Hydrocarbons

It is shown that for palladium catalysts supported on various supports, there is no effect of thermal activation consisting of an increase in the turnover number (TON) of palladium with an increase in the temperature of sample calcination from 500 to 700°C, as was observed in the case of similar supported platinum catalysts; for two palladium–alumina catalysts calcined at 500°C and differing in the concentration of palladium and dispersity, the TON of low-dispersity palladium is substantially higher than the TON of high-dispersity palladium; all other conditions being the same, the TON of supported palladium is determined by the support nature.     

M?ssbauer spectroscopic studies of the state of Pt?Sn/Al2O3 catalyst for hydrocarbon conversion

Mössbauer spectroscopic studies of the state of Pt–Sn catalyst for hydrocarbon conversion supported on prechlorinated -Al₂O₃ indicate that, unlike nonchlorinated Al₂O₃, this system is much more reduced and besides Pt₃Sn–PtSn₂, its surface contains sigfificant amounts of Sn(II) and Sn(IV) chlorides bonded to the surface.

---

Pt–Sn , -Al₂O₃. , Al₂O₃, Pt–Sn Pt₃Sn–PtSn₂ Sn(II) (IV), .

     

Effect of Thermal Activation of Supported Catalysts Pt/MeOx,Where MOx = Al2O3, CeO2, La2O3, and ZrO2, for Complete Oxidation

A sharp increase in the atomic catalytic activity (ACA) of supported platinum catalysts in the model reaction of n-pentane complete oxidation is found on going from the preliminary calcination temperature of 500–600°C to a temperature of 700°C. ACA increases by an order of magnitude for the Pt/-Al₂O₃ system, 3 times for Pt/ZrO₂, and 1.5 times for Pt/CeO₂. The per-gram activities of all catalysts decrease because of a decrease in the dispersion of supported platinum with an increase in the temperature of preliminary calcination.     

Isomerization of <Emphasis Type="Italic">n</Emphasis>-Heptane on Platinum-Zeolite Catalysts in the Presence of Cyclohexane and Benzene

Effect of cyclohexane and benzene on the isomerization of n-heptane on Pt/BEA-Al₂O₃ and Pt/MORAl₂O₃ catalysts was studied. In the presence of catalysts with platinum deposited from a [Pt(NH₃)₄]Cl₂ solution, cyclohexane and benzene inhibit the conversion of n-heptane. At the same time, the presence of cycloalkanes and aromatic hydrocarbons leads to an increase in the isomerization selectivity due to the suppression of side reactions of hydrocracking. Samples based on the BEA zeolite were found to be more active as compared with similar samples based on mordenite.     

O2-adsorption and (O2?H2)-titration on electron deficient platinum in reforming catalysts

Behavior of supported Pt in O₂ chemisorption and (O₂–H₂) titration has been studied. In Pt/SiO₂, Pt/-Al₂O₃ and Pt/-Al₂O₃ Pt^o catalysts are characterized by the following stoichiometric coefficients of oxygen adsorption (X), hydrogen adsorption (Y) and oxygen-hydrogen titration (Z) X:Y:Z=1:1:1.5. The co-efficients differ for Pt–Cl/-Al₂O₃ reforming catalysts. This is explained by the presence of electron deficient platium (Pt) with a coefficient ratio of X:Y:Z=0.5:2:1.5.     

Study of <Emphasis Type="Italic">n</Emphasis>-hexane isomerization on Pt/SO<Subscript>4</Subscript>/ZrO<Subscript>2</Subscript>/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalysts: Effect of the state of platinum on catalytic and adsorption properties

The state of surface Pt atoms in the Pt/SO₄/ZrO₂/Al₂O₃ catalyst and the effect of the state of platinum on its adsorption and catalytic properties in the reaction of n-hexane isomerization were studied. The Pt-X/Al₂O₃ alumina-platinum catalysts modified with various halogens (X = Br, Cl, and F) and their mechanical mixtures with the SO₄/ZrO₂/Al₂O₃ superacid catalyst were used in this study. With the use of IR spectroscopy (CO_ads), oxygen chemisorption, and oxygen-hydrogen titration, it was found that ionic platinum species were present on the reduced form of the catalysts. These species can adsorb to three hydrogen atoms per each surface platinum atom. The specific properties of ionic platinum manifested themselves in the formation of a hydride form of adsorbed hydrogen. It is believed that the catalytic activity and operational stability of the superacid system based on sulfated zirconium dioxide were due to the participation of ionic and metallic platinum in the activation of hydrogen for the reaction of n-hexane isomerization.     

New data about platinum state in reduced Pt/Al2O3(Cl) catalysts

A new quantitative method to determine the quantity of nonmetallic platinum in reduced catalysts whose state is close to Pt²⁺ is suggested.

---

, Pt²⁺.

     

Oxidized platinum surface in Pt/Al2O3 reforming catalysts: IR studies

The influence of halide ions on the state of dispersed Pt in oxidized catalysts has been investigated, adsorbed CO being used as a probe. Charged platinum complexes form upon catalyst oxygenation, with CO bands at 2130, 2150, 2165, 2170 and 2180 cm^–1. Composition of the complexes depends on the oxidation temperature and the nature of the halide ion.