Deactivation of a silica-alumina catalyst by coke deposition

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Industrial and Engineering Chemistry Research; (United States)

DOI:https://doi.org/10.1021/ie00023a028· OSTI ID:5626655

Garcia-Ochoa, F; Santos, A ^[1]

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1. Univ. Complutense, Madrid (Spain). Dept. de Ingenieria Quimica

Deactivation by fouling of a silica-alumina catalyst when it is used for cyclohexanol dehydration has been studied in a fixed bed laboratory reactor between 548 and 573 K. A kinetic model of the main reaction has been determined, corresponding to a mechanism in which the surface reaction in two active sites is the controlling step of the process rate. The deactivation rate has been determined from activity-time data, calculated from outlet conversion-time data. Coke precursor formation has been determined that occurs by reaction of three adsorbed molecules of reactant (cyclohexanol) or product (cyclohexene). A greater contribution (bigger parallel contribution) of coke formation from the reactant has been found. Also, the variation of different physical and chemical catalyst properties, such as surface, pore volume, acidity, and coke composition, have been measured at different coke contents, with the result that relationships between coke content and activity and between activity and acidity support the hypothesis of site coverage deactivation, at least for the coke level range achieved in this study (0--4.1 % (w/w), corresponding to an activity decay from 1 to 0.13); hence, the monolayer coke formation over the catalyst surface can be assumed. These results are confirmed by the nonvariation of physical properties.

• OSTI ID: 5626655
• Journal Information: Industrial and Engineering Chemistry Research; (United States), Journal Name: Industrial and Engineering Chemistry Research; (United States) Vol. 32:11; ISSN IECRED; ISSN 0888-5885
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COKE
DEACTIVATION
DEPOSITION
FOULING
KINETICS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHYSICAL PROPERTIES
POROSITY
REACTION KINETICS
SILICON COMPOUNDS
SILICON OXIDES
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K