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Catalytic conversion of rapeseed oil for the production of raw chemicals, fuels and carbon nanotubes over Ni-modified nanocrystalline and hierarchical ZSM-5

Paper ID Volume ID Publish Year Pages File Format Full-Text
45323 46409 2014 11 PDF Available
Title
Catalytic conversion of rapeseed oil for the production of raw chemicals, fuels and carbon nanotubes over Ni-modified nanocrystalline and hierarchical ZSM-5
Abstract

Catalytic conversion of rapeseed oil has been investigated over nanocrystalline and hierarchical ZSM-5 zeolites aimed to the production of both raw chemicals and fuels. Ni has been added to some of the samples in order to induce bifunctional properties in the catalysts. Almost total rapeseed conversion and deoxygenation degree were achieved with all the catalysts. The main products were gaseous olefins (mostly ethylene and propylene) and aromatic compounds (benzene, toluene and xylenes), which have high interest as raw chemicals. Likewise, high hydrogen contents are found in the gaseous stream since the operating conditions employed (high reaction temperature and atmospheric pressure) favor the occurrence of dehydrogenation reactions. The introduction of hierarchical porosity in ZSM-5 increases the production of light olefins at the expense of aromatic compounds, showing the close relationship between these two types of hydrocarbons. Hierarchical zeolites exhibit enhanced accessibility and diffusion rates, which hinders secondary reactions of the primary cracking products. Ni-containing catalysts show an enhanced dehydrogenation activity as denoted by the increased hydrogen, light olefins and coke production. Important changes were observed in the catalytic activity along time on stream, with a progressive increase in the fraction of aliphatic hydrocarbons. Interestingly, the coke formed over the Ni-containing ZSM-5 samples is in the form of carbon nanotubes, which grow causing a segregation of the Ni particle from the zeolite support. This effect is attenuated in the hierarchical zeolites because the secondary porosity stabilizes the metal particles. In summary, rapeseed oil can be transformed into valuable products (hydrogen, light olefins, aromatic hydrocarbons and carbon nanotubes) by using tailored Ni-containing nanocrystalline and hierarchical ZSM-5 zeolites.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► ZSM-5 shows a high selectivity for light olefins and gasoline aromatic hydrocarbons. ► Hierarchical ZSM-5 increases the yield of gaseous products at expense of aromatics. ► Ni-modified ZSM-5 enhances the production of light olefins reducing aromatics yield. ► The incorporation of nickel to the catalyst increases the formation of hydrogen. ► Carbon nanotubes are produced over the Ni-containing catalysts.

Keywords
Rapeseed oil; Nickel; ZSM-5 zeolite; Hierarchical zeolite
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Catalytic conversion of rapeseed oil for the production of raw chemicals, fuels and carbon nanotubes over Ni-modified nanocrystalline and hierarchical ZSM-5
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 145, February 2014, Pages 205–215
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