Activity, selectivity and stability of bimetallic catalysts inn-paraffin and cyclopentane reforming

PARERA, J.M.; QUERINI, CARLOS; BELTRAMINI, J.N.; FIGOLI, N.S.

APPLIED CATALYSIS A-GENERAL

ELSEVIER SCIENCE BV

Año: 1987 vol. 32 p. 117 - 132

0926-860X

Catalytic activity, selectivity and stability under commercial conditions of monometallic (Pt/Al2O3, 30 kg cm-2) and bimetallic catalysts (Pt-Re-S/Al2O3 and Pt-Ge/Al2O3, 15 kg cm-2) were compared in the reforming of nC5-nC1O paraffins, cyclopentane and methylcyclopentane. Under such conditions, the order of activity for n-paraffin transformation is Pt/Al2O3 > Pt-Re-S/Al2O3 > Pt-Ge/Al2O3 being Pt/Al2O3 the most active for hydrocracking, Pt-Re-S/Al2O3 for aromatization and Pt-Ge/Al2O3 for isomerization. Pt/Al2O3 has a minimum in coke formation and deactivation when n-heptane is fed, whereas on the bimetallics coke formation and deactivation increase from n-C5 with the increase in the n-paraffin length. Naphthenes of 5 C ring are the greatest coke producers on the three catalysts. Experiments with the bimetallics changing temperature showed that both catalysts have the same trend in selectivity, but for a similar selectivity the temperature must be 15-20°C higher in Pt-Ge/Al2O3 than in Pt-Re-S/Al2O3. These results and the comparison with literature data show the complexity of the phenomenon and the danger of extrapolating results to different experimental conditions.