Environmentally Friendly Fuel by n-Heptane Isomerization: Kinetics of Catalyst Deactivation

Abstract

Stringent environmental regulations demand reduced amounts of aromatics in a gasoline fuel. The aromatics have high octane rating and therefore by removing them from a gasoline fuel substantially decreases the quality of the gasoline. One way to improve the octane rating of heavy normal alkanes present in heavy naphtha, without converting them into aromatics, is to isomerize them over an acidic catalyst. Zeolites are acidic catalysts that are highly efficient for the isomerization reactions. In the present study, n-heptane is taken as a model component of heavy naphtha and kinetics of the deactivation of different Y zeolite catalysts during the hydroisomerization reaction is studied. Various deactivation rate laws are tested against the experimental data and the best-fit rate law is worked out. Relatively low activation energies for the deactivation process are obtained showing temperature has little effect on the rate of deactivation for the conditions studied in the present work.

Prediction of Alkyl Carbenium Ion Concentrations and Octane Number Increase in Heptane Hydroisomerization over a Pt/WO3/ZrO2 Catalyst

“…Kinetic modeling of n-C 7 hydroisomerization has been mostly carried out using power law models and based on the lumping of a small number of pseudocomponents. − A few studies have been carried out using Langmuir–Hinshelwood ,, and mechanistic ,, approaches. The results obtained with different catalysts and operating conditions have been useful to better understand the reaction mechanisms and to determine the global reaction rates and apparent activation energies.…”