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Highly effective P-modified HZSM-5 catalyst for the cracking of C4 alkanes to produce light olefins

Paper ID Volume ID Publish Year Pages File Format Full-Text
43464 45971 2008 7 PDF Available
Title
Highly effective P-modified HZSM-5 catalyst for the cracking of C4 alkanes to produce light olefins
Abstract

A series of HZSM-5 zeolites modified by different amounts of phosphorus (P/HZSM-5) were prepared. The physicochemical features of P/HZSM-5 catalysts were characterized by means of XRD, BET, NH3-TPD, FT-IR spectra of adsorbed pyridine, etc., and their performances for the catalytic cracking of the mixed C4 alkanes to produce light olefins were investigated. The results indicated that phosphorus (P) modification not only modulated the amount of acidic sites and the percentage of weak acidic sites in total acidic sites, but also regulated the acid type, i.e., the ratio of L/B (Lewis acid/Brönsted acid). The introduction of P also altered the basic characteristics of HZSM-5 which was evidenced by CO2-TPD analysis. Consequently, P modification with suitable amount was favorable for enhancing the selectivity to light olefins, especially to propene. At the temperature of 650 °C, the maximum yields of propene and ethene were achieved 25.6 and 33.9%, which were higher than those over parent HZSM-5 by 7 and 4.5%, respectively. Aromatics yield was found to be decreased with the increasing P loading due to the reduction of strong acid and the formation of new basic site which inhibited the hydrogen transfer reaction. All this indicates that P-modified HZSM-5 zeolites are effective catalysts for the cracking of mixed C4 alkanes to produce more light olefins.

Graphical abstractP-modified HZSM-5 was highly effective catalyst for the catalytic cracking of the mixed C4 alkanes to produce light olefins. The fact that P addition could modify both the acidic and basic characteristics of HZSM-5 (see figure) which in turn promoted its catalytic performance, will throw new light on the design of novel catalysts for light olefins. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Catalytic cracking; C4 alkanes; Light olefins; HZSM-5 zeolite; Phosphorus
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Highly effective P-modified HZSM-5 catalyst for the cracking of C4 alkanes to produce light olefins
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 340, Issue 2, 1 June 2008, Pages 176–182
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