Facile control of crystallite size of ZSM-5 catalyst for cracking of hexane

Mochizuki, Hidetaka; Yokoi, Toshiyuki; Imai, Hiroyuki; Watanabe, Ryota; Namba, Seitarô; Kondo, Junko N.; Tatsumi, Takashi

doi:10.1016/j.micromeso.2011.05.011

Cited by 169 publications

(113 citation statements)

References 30 publications

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“…Conversion decreased with increasing coke amount on every catalyst, but H-ZSM-5 with smaller crystallite size achieved higher conversion at the same coke amount. The higher activity caused by the slower deactivation of H-ZSM-5 with smaller crystallite size has been reported previously for the hexane cracking 21) . The slow deactivation was explained by the shorter diffusion paths and larger number of pore openings.…”

Section: Coke Formation On H-zsm-5 During Alkane Crackingsupporting

confidence: 76%

Coke Formation on Zeolite Catalysts in Naphtha Cracking

Komatsu

2018

J. Jpn. Petrol. Inst.

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Coke formation was investigated in the catalytic cracking of alkanes into light alkenes over ferrierite and ZSM-5 zeolites. H-ferrierite had the highest alkene selectivity in heptane cracking because of its smaller pore size. Ca 2 -exchange into H-ferrierite improved the selectivity and controlled coke formation. Ca 2 ions located at the center of the 8-membered ring converted ferrierite pores into one-dimensional channels of 10-membered rings, which suppressed the bimolecular hydride transfer to form alkanes and coke precursors. H-ZSM-5 zeolites having various extents of coke deposited in hexane cracking were characterized by adsorption measurements of various alkane molecules. Small amounts of coke did not affect the hexane conversion and micropore volume, whereas the adsorption rate of 2,3-dimethylbutane decreased significantly. These results suggest that coke is accumulated on the external surface of H-ZSM-5. Most coke would be formed via aromatic hydrocarbons. Selectivity for the transformation of aromatics into coke correlated with crystallite size of H-ZSM-5, indicating that aromatics formed in short channels can diffuse out of the crystallite immediately without coke precursor formation. H-ZSM-5 with smaller crystallite size is likely to be a stable catalyst for naphtha cracking into light alkenes with adequate catalyst life.

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Section: Coke Formation On H-zsm-5 During Alkane Crackingsupporting

confidence: 76%

Coke Formation on Zeolite Catalysts in Naphtha Cracking

Komatsu

2018

J. Jpn. Petrol. Inst.

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“…Moreover, carbon solid (coke) readily forms near the external surface of the crystal under diffusion controlled conditions, thereby, rapidly plugging the pores, leading to a short catalyst lifetime. To achieve low diffusion resistance, nano-sized zeolites are effective because the diffusion length for reactant/product hydrocarbons, which depends on the zeolite crystal size, is reduced [55,74,98]. High propylene selectivity from cracking of naphtha is favored over larger 10-membered ring zeolites having a pore index between 26 and 30.…”

Section: B Effect Of Crystal Sizementioning

confidence: 99%

Maximizing propylene production via FCC technology

2015

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This review looks at the main processes available for the production of light olefins with a focus on maximizing the production of propylene. Maximization of propylene production has become the focus of most refineries because it is in high demand and there is a supply shortage from modern steam crackers, which now produce relatively less propylene. The flexibility of the fluid catalytic cracking (FCC) to various reaction conditions makes it possible as one of the means to close the gap between supply and demand. The appropriate modification of the FCC process is accomplished by the synergistic integration of the catalyst, temperature, reaction-residence time, coke make, and hydrocarbon partial pressure. The main constraints for maximum propylene yield are based on having a suitable catalyst, suitable reactor configuration and reaction conditions.

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“…12 Reducing the crystalline size from the typical micrometer scale to the nanometer level shortens the diffusion pathway and improves the efficiency of molecule transportation. For example, decreasing the size of HZSM-5 to about 100 nm was found to markedly enhanced the catalytic stability in n-hexane cracking, 13,14 acetone to olefin, 15,16 methanol to gasoline, 17,18 and methanol to DME. 19 Nanosized Beta zeolites (80−100 nm) also exhibited activity and stability superior to those of the conventional zeolites with large particle sizes (2−4 μm) in acylation of anisole and toluene.…”

Section: Introductionmentioning

confidence: 99%

Dimethyl Ether Carbonylation to Methyl Acetate over Nanosized Mordenites

Xue

Huang

Ditzel³

et al. 2013

Ind. Eng. Chem. Res.

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Nanosized mordenites were found to show significantly enhanced reaction efficiency in dimethyl ether (DME) carbonylation to methyl acetate (MA) because of a greatly facilitated diffusion process. Copper incorporation into the channels of the nanosized mordenites further promoted the reaction rate, selectivity, and stability. Moreover, upon the addition of a small amount of H 2 (5−19 vol %) to the feed gas, deactivation was suppressed during DME carbonylation, whereas the catalyst stability and rate of formation of MA increased.

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Facile control of crystallite size of ZSM-5 catalyst for cracking of hexane

Cited by 169 publications

References 30 publications

Coke Formation on Zeolite Catalysts in Naphtha Cracking

Coke Formation on Zeolite Catalysts in Naphtha Cracking

Maximizing propylene production via FCC technology

Dimethyl Ether Carbonylation to Methyl Acetate over Nanosized Mordenites

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