Multinuclear NMR and catalytic investigations of deactivation of zeolite H-ZSM-5

Barrage, M. C.; Bauer, Frank; Ernst, H.; Fraissard, J.; Freude, D.; Pfeifer, H.

doi:10.1007/bf00774721

Cited by 18 publications

(3 citation statements)

References 9 publications

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“…In recent years, 13 C NMR in conjunction with proton cross-polarization (CP) and magic-angle spinning (MAS) has emerged as a powerful tool for studying the nature of the coke formed during hydrocarbon conversions over ze-olite catalysts (39)(40)(41). Valuable information such as the state and mobility of the adsorbates and details of the related guest/host interactions can be obtained (42)(43)(44)(45)(46)(47)(48). In the present work, the nature and distribution of the coke formed in H-beta zeolite during cumene disproportionation reactions are investigated by 13 C CP-MAS NMR spectroscopy in conjunction with thermogravimetric analysis.…”

Section: Introductionmentioning

confidence: 99%

Roles of Carrier Gases on Deactivation and Coking in Zeolite Beta during Cumene Disproportionation

Chen

Pradhan

Jong

et al. 1996

Journal of Catalysis

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Section: Introductionmentioning

confidence: 99%

Roles of Carrier Gases on Deactivation and Coking in Zeolite Beta during Cumene Disproportionation

Chen

Pradhan

Jong

et al. 1996

Journal of Catalysis

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“…Coke generated under Ar atmosphere showed clear 13 C chemical shifts at 130–140 ppm and 140–150 ppm, while relatively lower intensities were observed in the cases of steam and H 2 . The relative 13 C CP MAS NMR shift intensities were consistent with the coke amount, which means that the reduction of coke in steam and H 2 streams were mainly due to the decrease of aromatic C in coke.…”

Section: Resultsmentioning

confidence: 57%

Catalytic Fast Pyrolysis of Sewage Sludge over HZSM-5: A Study of Light Aromatics, Coke, and Nitrogen Migration under Different Atmospheres

Cao

Shan

et al. 2020

Ind. Eng. Chem. Res.

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Catalytic fast pyrolysis of sewage sludge was conducted considering the effects of pyrolysis temperature, atmospheres and catalysts on carbon and nitrogen distributions using a fixed-bed reactor. H2 atmosphere gave the lowest carbon selectivity of solid products and highest gaseous products yield over HZSM-5 (HZ) at the same temperature compared to Ar and steam. Higher temperature led to an increase in the carbon selectivity of gaseous products and a decrease in the carbon selectivity of solids. H2 increased the carbon yield of light aromatics (LAs), whereas steam reduced the generation of LAs. Over 0.5Ni-HZ, H2 gave the highest LAs carbon yield of 11.4%, compared to 1.6% obtained from noncatalytic fast pyrolysis of SS. Higher temperature, H2 and steam atmospheres, and metal-loaded HZ promoted the transfer of nitrogen into gaseous products. The highest nitrogen yield of NH3 of 55.6% was obtained from sludge pyrolysis over HZ at 700 °C under H2 atmosphere.

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“…In each case, the aromatic coke species also possess weak spinning sidebands at ~70 ppm and ~190 ppm, respectively; and again, these signals are more clearly seen on the post-reaction H-ZSM-5 samples. The band at ~17 ppm could be related to some aliphatic structures, and only-post reaction H-ZSM-5 samples and postreaction Al-H-ZSM-5 20 have a sharp peak [36]. The obtained 13 C-NMR results reveal that more coke species are adsorbed on the H-ZSM-5 samples, which have included both aromatic and less dehydrogenated aliphatic compounds.…”

Section: C-nmrmentioning

confidence: 87%

A Study into the γ-Al2O3 Binder Influence on Nano-H-ZSM-5 via Scaled-Up Laboratory Methanol-to-Hydrocarbon Reaction

et al. 2021

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Development of a laboratory selected zeolite into an industrial zeolite-based catalyst faces many challenges due to the scaling-up of reaction which requires many upgrades of the as-prepared catalyst such as an enhanced physical strength. To meet this requirement zeolite powders are normally mixed with various binders and then shaped into bulky bodies. Despite the fact there are a lot of reports on the positive features brought by the shaping treatment, there is still a great need to further explore the zeolite properties after the binder introduction. In this case, a lot of studies have been continuously conducted, however, many results were limited due to the usage of much smaller laboratory samples rather than a real factory plant, and more importantly, the maximal/minimal proportion of zeolites in the shaped catalyst. In this research, our shaped catalysts are based on nano-H-ZSM-5 zeolites and alumina (γ–Al2O3) binder while keeping the zeolite content to a maximum. H-ZSM-5 samples and Al-H-ZSM-5 samples are compared in the designed methanol-to-hydrocarbons reaction. With a reduced weight-hourly-space-velocity (WHSV = 1.5 h−1) and a higher reaction pressure (6 bar) favorable for aromatization, together with the tailored instruments for catalyst volume scale-up (20 g samples are tested each time), our tests focus on the early period catalytic performance (during the first 5 h). Unlike a normal laboratory test, the results from the scaled-up experiments provide important guidance for a potential industrial application. The role of the γ–Al2O3 introduced, not only as binder, but also performing as co-catalyst, on tailoring the early time product distribution, and the corresponding coke deposition is systematically investigated and discussed in details. Notably, the Si/Al ratio of H-ZSM-5 still has a decisive influence on the reaction performance of the Al-H-ZSM-5 samples.

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Multinuclear NMR and catalytic investigations of deactivation of zeolite H-ZSM-5

Cited by 18 publications

References 9 publications

Roles of Carrier Gases on Deactivation and Coking in Zeolite Beta during Cumene Disproportionation

Roles of Carrier Gases on Deactivation and Coking in Zeolite Beta during Cumene Disproportionation

Catalytic Fast Pyrolysis of Sewage Sludge over HZSM-5: A Study of Light Aromatics, Coke, and Nitrogen Migration under Different Atmospheres

A Study into the γ-Al2O3 Binder Influence on Nano-H-ZSM-5 via Scaled-Up Laboratory Methanol-to-Hydrocarbon Reaction

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