Propiedades catalíticas de catalizadores de Pt-Re-Pb/Al2O3 usados en reformado de naftas

VANINA A. MAZZIERI; MIGUEL A. D'AMATO; JAVIER M. GRAU; CARLOS R. VERA; JUAN C. YORI; CARLOS L. PIECK

Armação dos Búzios, Rio de Janeiro, Brasil

Congreso; XV Congreso Brasilero de Catálisis y el V Congreso de Catálisis del MERCOSUR; 2009

Se estudia la influencia del agregado de Pb sobre el desempeño catalítico de catalizadores de reformado de naftas de Pt-Re/Al2O3. Los catalizadores fueron preparados por coimpregnación. Los mismos fueron caracterizados por medio de reducción a temperatura programada, desorción de piridina a temperatura programada y diversas reacciones test tales como la deshidrogenación de ciclohexano, hidrogenólisis de ciclopentano y reformado de n-heptano. Se encontró que el Pb se encuentra en interacción con la fase activa (Pt-Re). Debido a ello la actividad de la función metálica disminuye, siendo más afectada la reacción de hidrogenólisis que la reacción de deshidrogenación. Parte del Pb se deposita sobre el soporte disminuyendo su acidez, principalmente los sitios de mayor fuerza ácida. La reacción de reformado de n-heptano muestra que el Pb modifica la estabilidad y selectividad de los catalizadores de Pt-Re. Pequeños agregados de Pb aumentan la estabilidad y mejoran significativamente la selectividad a isómeros de C7 y aromáticos mientras disminuye la formación de productos de menor valor como el metano y gases. This work explores the influence of Pb addition on the performance of Pt-Re/Al2O3 catalysts for catalytic naphtha reforming. The catalysts were prepared by a coimpregnation method. They were characterized by a temperature programmed reduction, temperature programmed desorption of pyridine and by several test reactions such as dehydrogenation of cyclohexane, hydrogenolysis of cyclopentane, and reforming of n-heptane. It was found that Pb chemically modifies the active phase (Pt-Re). As a result of this interaction the activity of metal decreases, hydrogenolysis being more affected than dehydrogenation. Some Pb is also deposited directly onto the support, decreasing its acidity.Strongest acid sites are mainly affected. Results for n-heptane reforming. show that the incorporation of Pb improves both stability and selectivity of Pt-Re catalysts. For this catalytic reaction, small amounts of Pb increased stability and significantly improve selectivity to C7 isomers and aromatics while decreasing the formation of lower-value products such as methane and another hydrocarbon gases. This work explores the influence of Pb addition on the performance of Pt-Re/Al2O3 catalysts for catalytic naphtha reforming. The catalysts were prepared by a coimpregnation method. They were characterized by a temperature programmed reduction, temperature programmed desorption of pyridine and by several test reactions such as dehydrogenation of cyclohexane, hydrogenolysis of cyclopentane, and reforming of n-heptane. It was found that Pb chemically modifies the active phase (Pt-Re). As a result of this interaction the activity of metal decreases, hydrogenolysis being more affected than dehydrogenation. Some Pb is also deposited directly onto the support, decreasing its acidity.Strongest acid sites are mainly affected. Results for n-heptane reforming. show that the incorporation of Pb improves both stability and selectivity of Pt-Re catalysts. For this catalytic reaction, small amounts of Pb increased stability and significantly improve selectivity to C7 isomers and aromatics while decreasing the formation of lower-value products such as methane and another hydrocarbon gases. 2O3. Los catalizadores fueron preparados por coimpregnación. Los mismos fueron caracterizados por medio de reducción a temperatura programada, desorción de piridina a temperatura programada y diversas reacciones test tales como la deshidrogenación de ciclohexano, hidrogenólisis de ciclopentano y reformado de n-heptano. Se encontró que el Pb se encuentra en interacción con la fase activa (Pt-Re). Debido a ello la actividad de la función metálica disminuye, siendo más afectada la reacción de hidrogenólisis que la reacción de deshidrogenación. Parte del Pb se deposita sobre el soporte disminuyendo su acidez, principalmente los sitios de mayor fuerza ácida. La reacción de reformado de n-heptano muestra que el Pb modifica la estabilidad y selectividad de los catalizadores de Pt-Re. Pequeños agregados de Pb aumentan la estabilidad y mejoran significativamente la selectividad a isómeros de C7 y aromáticos mientras disminuye la formación de productos de menor valor como el metano y gases. This work explores the influence of Pb addition on the performance of Pt-Re/Al2O3 catalysts for catalytic naphtha reforming. The catalysts were prepared by a coimpregnation method. They were characterized by a temperature programmed reduction, temperature programmed desorption of pyridine and by several test reactions such as dehydrogenation of cyclohexane, hydrogenolysis of cyclopentane, and reforming of n-heptane. It was found that Pb chemically modifies the active phase (Pt-Re). As a result of this interaction the activity of metal decreases, hydrogenolysis being more affected than dehydrogenation. Some Pb is also deposited directly onto the support, decreasing its acidity.Strongest acid sites are mainly affected. Results for n-heptane reforming. show that the incorporation of Pb improves both stability and selectivity of Pt-Re catalysts. For this catalytic reaction, small amounts of Pb increased stability and significantly improve selectivity to C7 isomers and aromatics while decreasing the formation of lower-value products such as methane and another hydrocarbon gases.2O3 catalysts for catalytic naphtha reforming. The catalysts were prepared by a coimpregnation method. They were characterized by a temperature programmed reduction, temperature programmed desorption of pyridine and by several test reactions such as dehydrogenation of cyclohexane, hydrogenolysis of cyclopentane, and reforming of n-heptane. It was found that Pb chemically modifies the active phase (Pt-Re). As a result of this interaction the activity of metal decreases, hydrogenolysis being more affected than dehydrogenation. Some Pb is also deposited directly onto the support, decreasing its acidity.Strongest acid sites are mainly affected. Results for n-heptane reforming. show that the incorporation of Pb improves both stability and selectivity of Pt-Re catalysts. For this catalytic reaction, small amounts of Pb increased stability and significantly improve selectivity to C7 isomers and aromatics while decreasing the formation of lower-value products such as methane and another hydrocarbon gases.