Temperature-programmed oxidation of equilibrium fluid catalytic cracking catalysts |
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Authors: | Bayraktar O Kugler E L |
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Institution: | 1.Department of Chemical Engineering, Izmir Institute of Technology, Gülbah?e K?yü, 35437, Urla-Izmir, Turkey E-mail ;2.Department of Chemical Engineering, CEMR, West Virginia University, P.O. Box 6102, Morgantown, WV, 26506-6102, USA ; |
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Abstract: | Characterization of coke on equilibrium, fluid catalytic cracking (FCC) catalysts contaminated with metals was investigated
using temperature-programmed oxidation (TPO). TPO spectra of spent equilibrium catalysts from cracking of sour imported heavy
gas oil (SIHGO) were deconvoluted into four peaks (Peak K, L, M and N). The four peaks were assigned to different types of
coke on the catalyst. Peak L in the TPO spectrum was assigned to the 'contaminant' coke in the vicinity of metals. The amount
of contaminant coke (Peak L) correlates with metal-contaminant concentration. The size of Peak L which is related to amount
of contaminant coke decreased significantly for the spent highly contaminated catalyst pretreated with hydrogen and methane
prior to cracking reactions as compared to the non-pretreated catalysts. Since both hydrogen and methane pretreatment can
reduce oxidation state of the vanadium that present at high concentrations on the equilibrium catalysts the decrease in the
amount of contaminant-coke represented by Peak L was explained by the reduction of the oxidation state of vanadium. Less contaminant
coke was produced after the equilibrium catalysts were pretreated using hydrogen and methane gases since reduced vanadium
has lower dehydrogenation activity compared to oxidized vanadium.
This revised version was published online in August 2006 with corrections to the Cover Date. |
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Keywords: | vanadium FCC catalysts temperature-programmed oxidation (TPO) coke characterization pretreatment |
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