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Kinetics of oxidative cracking of n‐hexane to olefins over VO x /Ce‐Al 2 O 3 under gas phase oxygen‐free environment
Author(s) -
Elbadawi AbdAlwadood H.,
Khan Muhammad Y.,
Quddus Mohammad R.,
Razzak Shaikh A.,
Hossain Mohammad M.
Publication year - 2017
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.15491
Subject(s) - dehydrogenation , chemistry , catalysis , olefin fiber , selectivity , fluid catalytic cracking , kinetics , hexane , reaction rate constant , oxygen , chemical kinetics , cracking , desorption , adsorption , analytical chemistry (journal) , thermodynamics , organic chemistry , physics , quantum mechanics
The kinetics of oxidative cracking of n‐hexane to olefins using lattice oxygen of VO x /Ce‐Al 2 O 3 is investigated. The TPR/TPO analysis shows a consistent reducibility (79%) of VO x /Ce‐Al 2 O 3 in repeated redox cycles. The total acidity of the sample is found to be 0.54 mmol/g with 22% are strong acid sites that favors olefin selectivity. The oxidative cracking of n‐hexane in a fluidized CREC Riser simulator gives approximately 60% olefin selectivity at 30% n‐hexane conversion. A kinetic model is developed considering (1) cracking, (2) oxidative dehydrogenation (ODH), and (3) catalyst deactivations. The proposed cracking mechanism considers adsorption, C–H and C–C bond fission and desorption as elementary steps and implemented by pseudo steady state hypothesis. A Langmuir‐Hinshelwood mechanism is found to represent the ODH reactions. The developed model fits the experimental data with favorable statistical indicators. The estimated specific reaction rate constants are also found to be consistent with the product selectivity data . © 2016 American Institute of Chemical Engineers AIChE J , 63: 130–138, 2017