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Fluid cracking catalysts catalytic selectivity

Prior to 1938, gasoline was obtained from thermal-cracking plants then the Houdry fixed-bed catalytic cracking process led to the development of a fluidized-bed process by Standard Oil for the catalytic production of motor fuels (4-8). Acid-treated clays of the montmorilIonite type were the first fluid-cracking catalysts widely employed by the industry. However, the ever greater demand for aviation fuels during the 1939-1945 period prompted the search for more active and selective catalysts. Research on novel catalyst... [Pg.1]

Evaluation of Coke Selectivity of Fluid Catalytic Cracking Catalysts... [Pg.340]

Zeolite catalysts provide the cracking function in many hydrocracking catalysts, as they do in fluid catalytic cracking catalysts. Zeolites are crystalline aluminosilicates, and among all commercial catalysts, the zeolite used at present is faujasite. Pentasil zeolites, including silicalite and ZSM-5 are also used for their ability to crack long chain paraffins selectively. [Pg.1287]

Selective Catalytic Reduction (SCR) has been commercially used since the mid 1980s on fired equipment with the hrst application on a boiler in 1976. The first SCR unit installed on a fluid catalytic cracking unit was at Saibu Oil Company in Yamaguchi, Japan in April 1986. Since then, nearly two dozen ECC units have installed SCR units to remove NO from the flue gas and more are slated to be built in the future. Vendors and catalyst suppliers of this technology include Haldor-Topsoe, Mitsubishi Power Systems, Hitachi, Technip, BASE, and Cormetech. [Pg.329]

Table 7 shows the yield distribution of the C4 isomers from different feedstocks with specific processing schemes. The largest yield of butylenes comes from the refineries processing middle distillates and from olefins plants cracking naphtha. The refinery product contains 35 to 65% butanes olefins plants, 3 to 5%. Catalyst type and operating severity determine the selectivity of the C4 isomer distribution (41) in the refinery process stream. Processes that parallel fluid catalytic cracking to produce butylenes and propylene from heavy cmde oil fractions are under development (42). [Pg.366]

Cerqueira and co-workers203 confirmed the appearance of the of the tetrahedral aluminium and phosphorus in AlPO-like crystalline structures both in beta (BEA) and in MOR zeolites treated with phosphoric acid. 31P MAS,27Al MAS and TQM AS NMR spectra permitted the species present in the samples to be assigned. Possibly, besides the the Altet-f species, other Al species are also taking part in the activity and selectivity of the catalysts. The formation of Alocl o P can also contribute to the increase in the activity by preventing further dealumination. Dual zeolite additives have no impact on the quality of naphtha when compared to MFI-based additives, which are used in the fluid catalytic cracking processes. [Pg.98]

In petrochemical and oil refining operations, the zeolite is primarily responsible for the catalyst s activity, selectivity and stability (catalytic, thermal and hydrothermal). The fluid catalytic cracking process (FCC) is the most widely used of the oil refining process and is characterized by the use of a finely divided catalyst, which is moved through the processing unit. The catalyst particles are of such a size (about 70 pm) that when aerated with air or hydrocarbon vapor, the catalyst behaves like a liquid and can be moved easily through pipes. [Pg.57]

Recent literature shows a growing trend to include free alumina in the formulation of fluid catalytic cracking (FCC) products. Over the last dozen years, FCC catalysts containing free alumina have been cited in the open and patent literature for benefits including (1) enhanced catalyst reactivity and selectivity (1-3). (2) more robust operation in the presence of metals in the petroleum feedstock (4-7). (3) improved attrition resistance (8.9). (4) improved hydrothermal stability against steam deactivation during regeneration (2.8). (5) increased pore volume and decreased bulk density (8), and (6) reduction of SOx emissions (10). [Pg.416]

Suib et at. (25, 254) reported the different effects of nickel and vanadium on the catalytic activity and selectivity for the fluid catalytic cracking by a photoluminescence technique and showed that the method is useful in predicting the catalyst deactivation caused by the deposition of metals on surfaces. The activity of the catalyst decreases monotonically with increasing vanadium content. With 1.5 wt% of V, the catalystad lost most of its activity, and with 2.0 wt% of V it became almost completely inactive. Such a deactivation of the catalyst was irreversible, with the extent being closely associated with the surface area covered with vanadium. Moreover, the extent of the deactivation was found to depend on the aging temperature, which was accelerated when aging was carried out under the same conditions normally sized in hydrothermal reactions. [Pg.244]

Microporous and, more recently, mesoporous solids comprise a class of materials with great relevance to catalysis (cf. Chapters 2 and 4). Because of the well-defined porous systems active sites can now be built in with molecular precision. The most important catalysts derived from these materials are the acid zeolites. The acid site is defined by the crystalline structure and exhibits great chemical and steric selectivities for catalytic conversions, such as fluid catalytic cracking and alkane isomerization (cf. Chapter 2). In Section 9.5 we discuss the synthesis of zeolites and, briefly, of mesoporous solids. [Pg.434]


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See also in sourсe #XX -- [ Pg.240 ]




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