Regeneration of Coked Zeolite Catalysts

Guisnet, M.

doi:10.1142/9781848166387_0012

Cited by 10 publications

(3 citation statements)

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“…4 shows the temporal evolution of the total coke contents deposited on the catalysts, which confirms the two coke formation/growth stages originally reported by Guisnet. 52 These steps consist of active site poisoning caused by reaction products/intermediates up to 2 h on stream, followed by a pore blockage. 53 The first step can be regarded as chemisorption, given the Langmuir adsorption behavior up to the formation of the monolayer.…”

Section: Resultsmentioning

confidence: 99%

“…53 The first step can be regarded as chemisorption, given the Langmuir adsorption behavior up to the formation of the monolayer. 52 At this stage, the formed oligomers sequentially make the ring and aromatize on the active site of the catalyst. 54 This stage of site poisoning coincides with a faster conversion decay over the initial 4 h on stream (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Direct analysis at temporal and molecular level of deactivating coke species formed on zeolite catalysts with diverse pore topologies

Hita

Mohamed

Yerrayya

et al. 2023

Catal. Sci. Technol.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Direct analysis at temporal and molecular level of deactivating coke species formed on zeolite catalysts with diverse pore topologies

Hita

Mohamed

Yerrayya

et al. 2023

Catal. Sci. Technol.

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“…The current industrial methods for removing coke from deactivated catalysts are mainly oxidation or combustion to convert the coke to CO 2 and CO. To avoid sintering of the active sites (metals) at high temperatures, the oxidation conditions have to be mild. The oxidation methods employed include temperature-programmed oxidation, − lean oxygen oxidation, and nitrogen oxide oxidation . These methods, however, have to be carried out off-site and involve shutting down the hydrotreating unit, unloading/loading the catalyst, and regenerating the deactivated catalyst in different reactors, which consequently are of high cost.…”

Section: Introductionmentioning

confidence: 99%

Coke Removal from a Deactivated Industrial Diesel Hydrogenation Catalyst by Tetralin at 300–400 °C

Shi

Liu

et al. 2019

Energy Fuels

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Coke deposition on hydrotreating catalysts is one of the main reasons of deactivation. In situ coke removal is advantageous compared to the off-site coke removal. This paper studies tetralin (THN) treatment of a deactivated industrial diesel hydrogenation Mo−Co−Ni/W−Al catalyst at conditions similar to the operation, 300−400 °C without H 2 . The results show that the coke on the Mo sulfide sites, corresponding to 19−23% total coke, can be removed in 3 min to fully restore the catalyst's activity. The coke on the support cannot be removed. On the basis of the temperature-programmed oxidation, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron spin resonance, coke removal mechanism is discussed, which includes activation of H radicals in THN by the Mo sulfide sites and hydrogenation of coke by the H radicals. The minimal requirement for the coke removal is 340 °C for 3 min. The side reactions of THN are significant at higher temperatures and longer treatment times. The radical concentration of coke on the Mo sulfide sites is similar to that of lignites and is approximately 10 times the coke on the catalyst support.

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Umwandlung von Methanol in Kohlenwasserstoffe: Wie Zeolith‐Hohlräume und Porengröße die Produktselektivität bestimmen

et al. 2012

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Flüssige Kohlenwasserstoffe nehmen aufgrund ihrer hohen Energiedichte und guten Transportfähigkeit eine Schlüsselrolle in der globalen Energieversorgung ein. Eine vergleichbare Bedeutung haben niedere Alkene wie Ethylen und Propylen in der Produktion von Verbrauchsgütern. In einer Gesellschaft der Nach‐Erdöl‐Zeit wird die Produktion von Kraftstoffen und Alkenen auf alternative Quellen wie Biomasse, Kohle, Erdgas und CO2 angewiesen sein. Die Umwandlung von Methanol in Kohlenwasserstoffe, bekannt als Methanol‐to‐ Hydrocarbons(MTH)‐Reaktion, könnte eine zentrale Rolle auf diesem Weg einnehmen, weil je nach Wahl des Katalysators und der Reaktionsbedingungen gezielt Benzin (Methanol‐to‐Gasoline, MTG) oder Alkene (Methanol‐to‐Olefins, MTO) hergestellt werden können. Dieser Aufsatz beschreibt eine Reihe von industriellen MTH‐Projekten, die in den letzten Jahren realisiert wurden, sowie den aktuellen Stand der Grundlagenforschung zur Synthese und Anwendung von mikroporösen Materialien für die gezielte Veränderung von Selektivität und Lebensdauer der Katalysatoren.

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Regeneration of Coked Zeolite Catalysts

Cited by 10 publications

References 0 publications

Direct analysis at temporal and molecular level of deactivating coke species formed on zeolite catalysts with diverse pore topologies

Direct analysis at temporal and molecular level of deactivating coke species formed on zeolite catalysts with diverse pore topologies

Coke Removal from a Deactivated Industrial Diesel Hydrogenation Catalyst by Tetralin at 300–400 °C

Umwandlung von Methanol in Kohlenwasserstoffe: Wie Zeolith‐Hohlräume und Porengröße die Produktselektivität bestimmen

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