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Hydrodesulfurization CoMo/Al2O3 and CoMo/C Catalysts Prepared with Nitrilotriacetic Acid without Use of NH4OH
Kaluža, Luděk ; Zdražil, Miroslav ; Vít, Zdeněk
We have calculated and experimentally confirmed that in the catalysts without NTA before sulfidation, the deposited phase takes up only about 5% of the pore volume of Al2O3 support. The deposited Co-Mo-O phase forms a monolayer and all Co-Mo-species are in physical and chemical contact with the support surface. In NTA catalysts before sulfidation, the deposited NTA-Co-Mo phase takes up about 60% of the pore volume of Al2O3. During sulfidation, the metal-support interaction of the majority of the Co and Mo species is blocked not only chemically by their own NTA ligands, but also physically by the surrounding supported solid. The majority of deposited solid in dried NTA catalysts is sulfided as if it were in the unsupported form. This leads to different morphology and structure of Co-Mo sulfides as compared with the catalysts without NTA. It was concluded that the overall NTA action is a combination of not only chemical effects described in the literature, but also of the above physical effect.
Plný tet: SKMBT_C22014082908312 -  PDF
Plný text: content.csg - PDF
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Activity of CoMo/MSA Catalysts in Benzothiophene Hydrodesulfurization, Cumene Cracking and Cyclohexene Isomerization
Gulková, Daniela ; Kaluža, Luděk ; Zdražil, Miroslav ; Vít, Zdeněk
It was found that MoO3 does not adsorb onto pure SiO2 despite its relatively high surface area (400 m2/g). In contrast, SA52, MSA30, and MSA19 with surface areas 430, 580 and 600 m2/g adsorbed about 14, 7 and 3 wt. % of MoO3, respectively. The content of Al2O3 in the SA based materials thus well correlated with the adsorption loadings of MoO3 achieved by the saturation experiments. Moreover, it was acquired that the highest dispersion and HDS activities were achieved over catalysts containing dealuminated MSA supports despite of relatively low loadings of Mo. After Co deposition, the weight normalized activities in BT HDS increased 2.2 and 4.3 times on effective MoS2 promotion by Co on more acidic supports. Furthermore, those catalysts keep the high acidities of the original supports, as it was determined by cyclohexene isomerization and cumene cracking, while industrial reference CoMo catalysts supported onto gamma-Al2O3 was found to exhibit low acidity.
Plný tet: SKMBT_C22012102413541 - PDF
Plný text: content.csg - PDF
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