The influence of Al2O3–ZrO2 and TiO2–ZrO2 supports on NiMo-supported catalysts at a different sulfur concentration in a model hydrodeoxygenation (HDO)-hydrodesulfurization (HDS) co-processing reaction has been studied in this work. A competition effect between phenol and dibenzothiophene (DBT) for active sites was evidenced. The competence for the active sites between phenol and DBT was measured by comparison of the initial reaction rate and selectivity at two sulfur concentrations (200 and 500 ppm S). NiMo/TiO2–ZrO2 was almost four-fold more active in phenol HDO co-processed with DBT than NiMo/Al2O3–ZrO2 catalyst. Consequently, more labile active sites are present on NiMo/TiO2–ZrO2 than in NiMo/Al2O3–ZrO2 confirmed by the decrease in co-processing competition for the active sites between phenol and DBT. DBT molecules react at hydrogenolysis sites (edge and rim) preferentially so that phenol reacts at hydrogenation sites (edge and edge). However, the hydrogenated capacity would be lost when the sulfur content was increased. In general, both catalysts showed similar functionalities but different degrees of competition according to the highly active NiMoS phase availability. TiO2–ZrO2 as the support provided weaker metal-support interaction than Al2O3–ZrO2, generating a larger fraction of easily reducible octahedrally coordinated Mo- and Ni-oxide species, causing that NiMo/TiO2–ZrO2 generated precursors of MoS2 crystallites with a longer length and stacking but with a higher degree of Ni-promotion than NiMo/Al2O3–ZrO2 catalyst.
5.1.2.5.Espectroscopía fotoelectrónica de rayos X (XPS)……………... 5.1.2.6.Microscopía de electrónica de transmisión de alta resolución (HRTEM)…………………………………………………… 5.1.2.7.Cuantificación de coque en los catalizadores usados mediante TPO…………………………………………………………….. 5.2.EVALUACIÓN CATALÍTICA DE MATERIALES…………………... 5.2.1. Hidrodesulfuración de DBT con catalizadores de W soportado…... 5.2.2. Efecto de variación de temperatura de sulfuración………………... 5.2.3. Efecto de variación de pH de impregnación……………………… 5.2.4. Hidrodesulfuración de DBT con catalizadores de NiW soportados………………………………………………………….. 6. DISCUSIÓN DE RESULTADOS………………………………………….. 6.1.CATALIZADORES DE W SOPORTADO…………………………….. 6.1.1. Efecto de la composición del soporte…..…………………………. 6.1.2. Efecto del pH de impregnación……………………………………. 100 6.2.CATALIZADORES DE NiW SOPORTADO………………………… 102 6.2.1. Influencia del níquel……………………………………………….. 102 6.2.2. Efecto de la composición del soporte……………………………... 104 CONCLUSIONES…………………………………………………………... 109 REFERENCIAS…………………………………………………………….. 112 APÉNDICE A………………………………………………………………. 120 APÉNDICE B……………………………………………………………….. 121 APÉNDICE C……………………………………………………………….. 123 APÉNDICE C -TERMODINÁMICA DE LA REACCIÓN DE HDS DE DBT C.1. Entalpías de formación (298 K), energías libres de formación (298 K) y variación del calor específico con la temperatura para los compuestos implicados en la DSD del DBT.C.2. Termodinámica de la reacción de DSD de DBT a 320 °C. C.3. Entalpías de formación y energías libres de formación (298 K) y variación del calor específico para los compuestos implicados en la hidrogenación de bifenil.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.