Kinetics of heptane reforming on Pt/L zeolite

Abstract

The kinetics of heptane reforming over 0.64% Pt/KBaL have been measured over a wide range of conditions from 390 to 475 ° C, 0.05 to 1.00 atm heptane, and 0.2 to 25.0 atm hydrogen. Below about 6 atm H₂, the catalyst deactivates due to carbon fouling of the platinum particles. The reaction rate increases with hydrogen pressure under these conditions, presumably because this accelerates the rate of carbon hydrogenation off the metal surface. Above 6 atm H₂, no deactivation occurs. The activation energies and reaction orders in heptane and hydrogen at high H₂ pressure are: 39 kcal/mol, 0.7 and −1.9 for hydrogenolysis; 60 kcal/mol, 0.6 and −2.8 for isomerization; and 58 kcal/mol, 0.4 and −2.7 for dehydrocyclization. These kinetics are the same as those observed over platinum on nonacidic supports, and indicate that the reaction mechanism on Pt/KBaL is no different from that on monofunctional Pt catalysts.