Deoxygenation of oleic acid methyl ester in FCC process conditions over protonated and sodium exchanged Y and ZSM-5 zeolites

One way to take advantage from out of specification biodiesel and waste from biodiesel tank bottom drainage is to co-process them in a fluidized catalytic cracking (FCC) unit. The present work deals with the cracking of oleic acid methyl ester (OAME) as a biodiesel model, under conditions close to that of FCC process over ZSM-5 and Y zeolites, either in protonated or sodium forms, for the production of deoxygenated compounds. Catalytic fast cracking of OAME pre-adsorbed on the catalyst surface was performed, with a catalyst:OAME mass ratio of 10:1 in a micro-pyrolysis system at 650°C, coupled to a GC/MS for on line analysis of the products. Results show that the cracking of OAME without a catalyst favored the formation of linear alkenes and polyenes. Fast cracking of OAME over HZSM-5 and HY acidic zeolites led to the production of aromatics, due to hydrogen transfer. Cracking over NaY and HY zeolites produced remarkable amounts of ramified saturated hydrocarbons. The formation of alkylated hydrocarbons was not significant over ZSM-5 zeolite probably due to a small pore size of this zeolite. NaY catalyst favored the production of hydrocarbons in the range of kerosene (C8-C12). Low acidic zeolites favored the production of non-aromatic hydrocarbons. Product distribution was affected by catalyst shape selectivity and acidity. These results show that residues from the biodiesel chain can be directly co-processed in FCC units to obtain high value hydrocarbons, mainly in the jet fuel and gasoline ranges.

Acid Properties of Hierarchical Zeolites Y

The article reviews different strategies towards obtaining mesoporous zeolites Y: desilication; surfactant templating and assembly of zeolite crystals. The impact of those methods on physicochemical properties is covered, with a special focus on the acidity of the samples measured with infrared (IR) spectroscopy. The methods of characterization of acidity are presented. Quaternary ammonium cations used for desilication lead to obtaining crystalline; mesoporous and highly acidic zeolites. Si-OH-Al groups of extremely high acidity can be produced by calcination in a humid atmosphere. When the conditions are optimized, post-synthetic surfactant templating allows crystalline mesoporous zeolite to be obtained with no loss of material. All mesoporous zeolites Y proved to be active catalysts in liquid phase isomerization, catalytic cracking, and other reactions.