Evolución de las propiedades del catalizador de reformado PtGe/Al2O3-Cl en función del contenido de Ge

F.C. GALISTEO; R. MARISCAL; J.L.G. FIERRO; G. COLLINS; J.C. YORI; J.M. PARERA; J.M. GRAU

Mérida, Yucatán, México

Simposio; XIX Simposio Iberoamericano de Catálisis; 2004

Instituto Mexicano del Petróleo - UNAM

The effect of the atomic ratio Pt/Ge on the catalytic activity of PtGe/Al2O3 catalysts used in nheptane reforming was studied. The samples were prepared by the coimpregnation method on chlorinated alumina. The content of Pt was 0.5%, and Ge-loading was varied to obtain atomic ratios Pt/Ge of 0.3, 0.7, 1.4, 2.1 and 3.5. Pt/Al2O3 and Ge/Al2O3 catalysts were also prepared as references. The characterization was carried out by temperature programmed reduction (TPR), FTIR spectroscopy of adsorbed CO, cyclohexane dehydrogenation and n-heptane reforming. It was found that Ge decreases the metal activity of Pt by modifying its electronic state and neutralizes the strong acid sites of alumina, thus decreasing the formation of cracking products and coke. As a result both conversion and catalytic stability increased. The results show that a maximun isoparaffin yield is reached for a Ge-loading of 0.27%. The increase in Ge content led to a decrease in the hydrogenolysis activity and the aromatics formation, an increase in the isomers and cicloparaffins formation, and reduction of the production of gas and the deactivation by coke, thus improving catalyst stability. Key words: n-heptane reforming, PtGe catalysts, optimization of Pt/promoter ratio.