Growth mechanism of coke on HBEA zeolite during ethanol transformation

Pinard, Ludovic; Hamieh, Tayssir; Canaff, Christine; Madeira, F. Ferreira; Batonneau−Gener, Isabelle; Maury, S.; Delpoux, O.; Tayeb, K. Ben; Pouilloux, Yannick; Vezin, Hervé

doi:10.1016/j.jcat.2012.12.018

Cited by 55 publications

(34 citation statements)

References 37 publications

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“…In agreement with the observations reported by Pinard et al and Rojo-Gama et al, lower weight hydrocarbons such as alkylbenzenes were detected at retention times ranging from 7 to 17 min, while at higher retention time, heavier polycyclic hydrocarbons including alkylnaphthalene, alkylanthracenes, and phenanthrenes were found (Table 6) [58,59]. Due to the fact that the selected active phases, reaction temperature, and reaction time were kept the same for all catalytic oxidation tests [58,62], no significant change of coke composition was observed among the samples analyzed.…”

Section: Characterization Of the Used Catalystsupporting

confidence: 91%

“…In addition, differences in CO 2 yields were also evident between samples prepared on the same support, as shown in Figure 7. The discrepancy between benzene conversion and CO 2 yield and the absence of volatile byproducts of a reaction could be attributed to the formation of coke on the support's surface, as is commonly observed during the oxidation of benzene by other catalysts [58][59][60]. The formation of coke was studied and the results will be presented in Section 2.5.…”

Section: Characterization Of the Used Catalystmentioning

confidence: 99%

“…In addition, only minor variations of coke content were observed among samples prepared on the same support, indicating that the duration of oxidation tests appeared to be sufficient to stabilize the coking formation. The formation of coke is usually observed inside the porous structure of catalyst, eventually in areas not covered by the active phase, and its growth in time leads to the deactivation of catalyst [43,58]. Li et al also reported that the support's porous structure might influence the quantity of coke deposited [61].…”

Section: Characterization Of the Used Catalystmentioning

confidence: 99%

See 2 more Smart Citations

A Comparative Study of Mn/Co Binary Metal Catalysts Supported on Two Commercial Diatomaceous Earths for Oxidation of Benzene

Tomatis

Wei

et al. 2018

Catalysts

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Two commercial diatomaceous earths were used as supports for the preparation of Mn/Co binary metal catalysts at different metal loads (5 to 10 wt % Mn and 5 to 15 wt % Co) by incipient wetness deposition. The activity of the prepared catalysts towards the complete oxidation of benzene to CO 2 and water was investigated between 100 and 400 • C. Raw supports and synthesized catalysts were characterized by XRD, N 2 physisorption, SEM-EDS, H 2 -TPR, and TPD. The purification treatment of food-grade diatomite significantly affected the crystallinity of this support while reducing its specific surface area (SSA). A loss of SSA, associated with the increase in the metal load, was observed on samples prepared on natural diatomite, while the opposite trend occurred with food-grade diatomite-supported catalysts. Metal nanoparticles of around 50 nm diameter were observed on the catalysts' surface by SEM analysis. EDS analysis confirmed the uniform deposition of the active phases on the support's surface. A larger H 2 consumption was found by TPR analysis of natural diatomite-based samples in comparison to those prepared at the same metal load on food-grade diatomite. During the catalytic oxidation experiment, over 90% conversion of benzene were achieved at a reaction temperature of 225 • C by all of the prepared samples. In addition, the formation of coke during the oxidation tests was demonstrated by TGA analysis and the soluble fraction of the produced coke was characterized by GC-MS.

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Section: Characterization Of the Used Catalystsupporting

confidence: 91%

Section: Characterization Of the Used Catalystmentioning

confidence: 99%

Section: Characterization Of the Used Catalystmentioning

confidence: 99%

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A Comparative Study of Mn/Co Binary Metal Catalysts Supported on Two Commercial Diatomaceous Earths for Oxidation of Benzene

Tomatis

Wei

et al. 2018

Catalysts

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“…The presence of absorption bands in the CH stretching region of paraffinic groups (3000-2800 cm −1 ) after in situ air treatment of EtOH-laden NaY-SiO 2 ( Figure 6A) indicated the formation of coke on NaYR (HF) and NaYR (LF) [27]. In contrast, no absorption bands in this region being observed for Pt/NaY-SiO 2 suggests the roles of Pt in inhibiting coke formed on Pt/NaY-SiO 2 during regeneration.…”

Section: Characterization Of Surface Species On Nay-sio 2 and Pt/nay-mentioning

confidence: 99%

“…There were no aromatic-coke characteristic absorption bands in the range between 3000 and 3200 cm −1 observed, suggesting that cokes formed on NaY-SiO2 are mostly paraffinic ( Figure 6A) [27]. The absorption bands at 2974 cm −1 and 2842 cm −1 were assigned to asymmetric stretching (νsym) and symmetric vibration (νasym), respectively, for CH3, and the absorption bands at 2930 cm −1 (νsym) and 2894 cm −1 (νsym) were assigned to νsym and νasym, respectively, for CH2.…”

Section: Characterization Of Surface Species On Nay-sio2 and Pt/nay-smentioning

confidence: 99%

Air Regeneration of Ethanol-Laden Pellet NaY-SiO2 and Pt/NaY-SiO2: Effects of Air Flow Rate on Pt Morphology and Regeneration Efficiency

Yeh

Chen

et al. 2018

Catalysts

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Regeneration process and adsorbent performance were investigated by a fixed-bed adsorber at 300 • C. Surface species, zeolite structure, and Pt morphology were characterized by FT-IR, XRPD and EXAFS, respectively. Performance test results indicated that ethanol adsorption capacity of Pt/NaY-SiO 2 is about 2.5 times that of NaY-SiO 2 . After regeneration, adsorption-capacity loss is 2.5 and 43%, respectively, for Pt/NaY-SiO 2 regenerated at superficial velocity of 13.2 (PtR (HF) ) and 5.3 cm/min (PtR (LF) ); in contrast, it is 8 and 21%, respectively, for NaYR (HF) and NaYR (LF) . The appearance of absorption bands in the CH stretching region (υ CH ) of the IR spectra characterizing the regenerated NaY-SiO 2 suggested that the adsorption-capacity loss for NaY-SiO 2 was mainly caused by the deposition of carbonaceous species formed in regeneration, which cannot be burned off readily at 300 • C. In contrast, no υ CH bands have been observed for the IR spectra of PtR (HF) and PtR (LF) , indicating that Pt helps to burn off carbonaceous species. However, Pt agglomeration was observed in TEM and EXAFS for Pt/NaY-SiO 2(LF) . The appearance of a υ CO band at about 2085 cm −1 of the IR spectra characterizing PtR (LF) suggested that Pt agglomeration was induced by CO adsorption. The growth of Pt particles decreases the ethanol adsorbed on Pt together with the conversion of ethanol to ethoxides and aldehyde, leading to a decrease of adsorption capacity.

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Identification of the coke deposited on 13X industrial zeolite molecular sieves during mercaptan removal process

Asl

Sargolzaei

Moosavi

2015

Asia-Pacific J Chem Eng

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Industrial Z10-13X zeolite was deactivated by coking during the sequenced pressure and temperature swing mercaptan removal unit at the conditions of 40°C and 68 bar in adsorption mode and 300°C and 8 bar in regeneration mode. In this study, detailed coke features inside industrial molecular sieves, in terms of molecular structure and also some other brief properties, have been obtained for the first time by combining numerous techniques including gas chromatography coupled with mass spectrometry, thermogravimetric analysis, Brunauer-Emmett-Teller analysis, energy-dispersive X-ray spectroscopy, X-Ray diffraction pattern, and also CO 2 and N 2 adsorption/desorption isotherms of fresh and coked molecular sieves. The coke species were identified and classified into more than 40 different components following their alkylation and cyclization mechanisms. The coke includes polyaromatic hydrocarbons, and it was much alkylated especially with methyl and ethyl fragments. It is mainly compounded of derivatives of benzene located within the zeolite pore, which could grow into polyaromatic compounds constituted up to four aromatic rings with different guest polar elements.

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Growth mechanism of coke on HBEA zeolite during ethanol transformation

Cited by 55 publications

References 37 publications

A Comparative Study of Mn/Co Binary Metal Catalysts Supported on Two Commercial Diatomaceous Earths for Oxidation of Benzene

A Comparative Study of Mn/Co Binary Metal Catalysts Supported on Two Commercial Diatomaceous Earths for Oxidation of Benzene

Air Regeneration of Ethanol-Laden Pellet NaY-SiO2 and Pt/NaY-SiO2: Effects of Air Flow Rate on Pt Morphology and Regeneration Efficiency

Identification of the coke deposited on 13X industrial zeolite molecular sieves during mercaptan removal process

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