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Ethylation of coking benzene over nanoscale HZSM-5 zeolites: Effects of hydrothermal treatment, calcination and La2O3 modification

Paper ID Volume ID Publish Year Pages File Format Full-Text
42729 45938 2009 8 PDF Available
Title
Ethylation of coking benzene over nanoscale HZSM-5 zeolites: Effects of hydrothermal treatment, calcination and La2O3 modification
Abstract

The objective of this work is to study some post-treatment effects, including hydrothermal treatment, calcination and La2O3 modification, on the catalytic performance of a nanoscale HZSM-5 zeolite for ethylation of coking benzene. The nanoscale HZSM-5 zeolite was treated by hydrothermal treatment, calcination and La2O3 modification in series, and the prepared catalysts were evaluated in a fixed-bed down-flow reactor. The catalyst samples were also characterized by XRD, SEM, NH3-TPD, IR, N2 adsorption–desorption isotherms, cyclohexane adsorption isotherms and TG. The results showed that both the hydrothermal treatment and the calcination led to a drastic decrease in the total amount of acid sites, while the subsequent La2O3 modification resulted in only a slight increase in the number of acid sites. These post-treatments led to a decrease in the Brönsted/Lewis ratio of the nanoscale HZSM-5 zeolites. The hydrothermal treatment followed by the La2O3 modification created new large micropores on the nanoscale HZSM-5 zeolites, which results in the coexistence of micropores and large micropores. The increase in the catalyst lifetime can be attributed to both suppression of carbon deposit formation and partial accommodation of the formed carbon deposit in La-C-HT-HZSM-5 catalyst with lower acidity, lower ratio of B/L and complicated pore structure. The prepared La-C-HT-HZSM-5 catalyst showed good catalytic stability within 1500 h of time on stream in the ethylation of coking benzene containing high sulfur content (375 ppmw) with ethylene under industrial reaction conditions.

Graphical abstractThe objective of this work is to study some post-treatment effects, including hydrothermal treatment, calcination and La2O3 modification, on the catalytic performance of a nanoscale HZSM-5 zeolite for ethylation of coking benzene in a fixed-bed down-flow reactor. The prepared La-C-HT-HZSM-5 catalyst showed good catalytic stability within 1500 h of time on stream in the ethylation of coking benzene containing high sulfur content (375 ppmw) with ethylene under industrial reaction conditions.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Coking benzene; Nanoscale HZSM-5; Hydrothermal treatment; Calcination; La2O3 modification
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Ethylation of coking benzene over nanoscale HZSM-5 zeolites: Effects of hydrothermal treatment, calcination and La2O3 modification
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 355, Issues 1–2, 28 February 2009, Pages 184–191
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us