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Ethanol dehydration to ethylene on acid carbon catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
46854 46451 2011 9 PDF Available
Title
Ethanol dehydration to ethylene on acid carbon catalysts
Abstract

Gas phase ethanol decomposition over acid carbon catalysts has been studied. The acid carbon catalysts were obtained by chemical activation of olive stone with phosphoric acid, without needing additional oxidative treatments. Different impregnation ratios, between 0.5 and 2, and activation temperatures, in the interval 400–800 °C, were used for the preparation of the carbons. Impregnation ratio shows more influence in the porous structure development than that observed for the activation temperature. XPS analyses reveal that the amount of stable phosphorus remaining over the carbon surface after the washing process increases with both activation temperature and impregnation ratio. FTIR spectra confirm the presence of surface phosphorus in form of phosphate and polyphosphate groups. XPS analyses suggest the existence of C–O–PO3 and C–PO3 surface groups that present acid character and of C3PO and C3P type. The increase of the activation temperature results in an increase in the proportion of C3PO and C3P surface groups. The catalytic decomposition of ethanol over the activated carbons yields mainly dehydration products, mostly ethylene with lower amounts of diethyl ether. In absence of oxygen the catalysts suffer a progressive deactivation. However, the presence of oxygen produces a significant increase of the ethanol conversion without any significant change in the selectivity of reaction and avoids deactivation of the catalysts under the operation conditions studied. The results suggest that oxygen inhibits coke deposition on the acid active sites. Ethanol conversion remains practically constant and selectivity does not change when water vapor is added to the reactor feed in concentration similar to that of bio-ethanol.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Gas phase ethanol dehydration to ethylene over acid carbon catalysts has been studied. ► The catalysts were obtained by chemical activation of olive stone waste with H3PO4. ► The presence of oxygen increases the ethanol conversion and avoids deactivation. ► Conversion and selectivity remain constant when water vapor is added to the reactor.

Keywords
Biorefinery; Bio-ethanol; Dehydration; Ethylene; Acid activated carbon; Deactivation
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Ethanol dehydration to ethylene on acid carbon catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 103, Issues 3–4, 5 April 2011, Pages 302–310
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