Catalytic conversion of rapeseed oil into raw chemicals and fuels over Ni- and Mo-modified nanocrystalline ZSM-5 zeolite
The conversion of rapeseed oil has been investigated using Mo oxide- and Ni-modified nanocrystalline ZSM-5 zeolites as catalysts in a nitrogen atmosphere. The incorporation of metals into the HZSM-5 support causes significant changes in their acid and textural properties, modifying also its catalytic behavior. For all the catalysts, an almost total deoxygenation of the rapeseed oil takes place as denoted by the formation of CO and in a lesser extension of CO2 and H2O. The main reaction products were light olefins (mainly ethylene and propylene) and aromatic hydrocarbons (BTX). Ni/HZSM-5 catalysts exhibit a higher selectivity toward the formation of light olefins, whereas for Mo/HZSM-5 catalysts the product distribution is shifted toward aromatics. Differences in the evolution of the product distribution along the time on stream were also observed as a result of the formation of different types of coke over the catalysts. A great amount of highly polyaromatic coke was formed over the Ni/HZSM-5 samples, whereas a less structured coke is deposited over the parent zeolite and the Mo/HZSM-5 catalysts. These results show that the incorporation of metals over nanocrystalline ZSM-5 leads to catalysts with interesting properties for the conversion of vegetable oils into raw chemicals and fuels.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (314 K)Download as PowerPoint slideHighlights► Ni- and Mo-modified nanocrystalline HZSM-5 bifunctional catalysts for conversion of rapeseed oil. ► Ni and Mo cause strong changes in acid, textural and catalytic properties of nanocrystalline HZSM-5 zeolite. ► A high degree of rapeseed oil deoxygenation takes place with Ni/HZSM-5 and Mo/HZSM-5 catalysts. ► Light olefins and aromatic hydrocarbons are the main reaction products using Ni/HZSM-5 and Mo/HZSM-5 catalysts. ► Ni/HZSM-5 catalysts keep a remarkable cracking activity in spite of the formation of high amounts of polyaromatic coke.
Journal: Catalysis Today - Volume 195, Issue 1, 15 November 2012, Pages 59–70