IRON CATALYST DEACTIVATION BY CARBON DEPOSITION FROM SYNTHESIS GAS.
Item
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Title
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IRON CATALYST DEACTIVATION BY CARBON DEPOSITION FROM SYNTHESIS GAS.
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Identifier
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AAI8601637
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identifier
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8601637
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Creator
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FERNANDEZ-RAONE, ELVIO DANIEL.
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Contributor
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Alberto LaCava
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Date
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1985
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Language
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English
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Publisher
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City University of New York.
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Subject
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Engineering, Chemical
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Abstract
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The kinetics of C deposition and CO(,2) formation from CO over Fe powders, foils and supported pellets was studied at temperatures ranging from 250 to 450 C, using a microbalance tubular flow reactor. Carbon deposition proceeds at constant rates over all catalysts. The dependence of the rates on the CO partial pressure seems to follow a zero order power law kinetics in the range of study. Arrhenius plots show the activation energies for the rates of deposition and formation to be 31-32 Kcal/gmol.;The kinetics of carbon gasification with H(,2), from C deposited on Fe supported pellets was studied on the same system, at temperatures in the range 350-450 C. CH(,4) was the only detectable gaseous product. Constant rates of C gasification and CH(,4) formation could be maintained for 2 to 3 days of continuous operation. Activation energies of 48 Kcal/gmol were obtained for both reactions.;Deactivation of commercial iron pellets by C deposition from pure CO was studied in the range 280 to 320 C. After an initial deactivation process, constant rates of deposition were achieved through filamentous growths. A pore blocking mechanism seems to explain the behaviour of these catalysts for the C deposition reaction.;Non-porous iron pellets were deactivated by C deposition (300-350 C) from pure CO and regenerated by hydrogenation (370-415 C). Both reactions behave similarly. An initial constant high rate is followed by deactivation and a much lower constant final rate. This can be explained by assuming an uneven patch-like iron distribution on the pellet surface.;C deposits from pure CO were readily gasified to methane from porous and non-porous pellets. The order of reaction with respect to hydrogen partial pressure appears to be 1. This seems to be consistent with a mechanism in which the formation of a CH(,2)M group is the rate limiting step.;Hydrogen increases the rate of C formation from pure CO. The order of reaction with respect to the hydrogen partial pressure varies with the hydrogen partial pressure.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Engineering
