Mass transport characteristics of zeolite cracking catalysts. Quarterly report, April 1-June 30, 1979

Technical Report · Tue Jan 01 04:00:00 EST 1980

DOI:https://doi.org/10.2172/5723591· OSTI ID:5723591

Haynes, Jr., H. W.

Previous reports have pointed out the discrepancy between our n-butane/NaY diffusivity measurements and the linear chromatography theory. A series of experiments has been completed which clearly demonstrates the existence of nonlinearities in this system. A similar discrepancy is evident in the system n-hexane/NaY. In contrast, the results for diffusion of 2,2-dimethylbutane, cyclohexane and t-decalin in zeolite NaY at 280/sup 0/C are well described by the theory. Surprisingly, no diffusion effects are observed in these systems. The diffusion is too rapid to be detected. The cracking of decalin and other hydrocarbons over various acid forms of zeolite -Y has been studied. Arrhenius plots of the first order rate constant for decalin conversion exhibit well-defined breakpoints indicative of a transition from the kinetics regime to an intracrystalline diffusion regime. By setting the Thiele modulus equal to unity at the breakpoint it is possible to estimate the diffusivity. This appears to be the first time that values of intracrystalline diffusivity have been reported for a species in a reaction environment. A series of hydrocracking studies over a NiWHUSY zeolite has been completed. Some problems were experienced with temporary plugging during hydrogenated pyrene runs, and the carbon material balances were rather poor. Excellent material balances were obtained during the tetralin runs. The catalyst is quite active for conversion of the hydrogenated pyrenes despite the large molecular size. An analysis of the kinetics is underway.

• Research Organization: Mississippi Univ., University (USA). Dept. of Chemical Engineering
• OSTI ID: 5723591
• Report Number(s): FE-2727-7
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
ALKANES
AROMATICS
BUTANE
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COAL LIQUEFACTION
COAL LIQUIDS
CRACKING
CYCLOALKANES
CYCLOHEXANE
DECALIN
DECOMPOSITION
DIFFUSION
HEXANE
HYDROCARBONS
HYDROCRACKING
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
LIQUEFACTION
MINERALS
ORGANIC COMPOUNDS
PYROLYSIS
TETRALIN
THERMOCHEMICAL PROCESSES
ZEOLITES