AbstractThe effect of run time, surface area, reaction temperature and inlet naphtha partial pressure on the rate of coke formation during naphtha pyrolysis has been investigated in a jet‐stirred reactor. The pyrolysis products could be predicted by a model developed earlier for naphtha pyrolysis. Various simplified models for the coke formation involving either the reactant or products were postulated and the kinetic parameters determined by a statistical analysis. The rate of coke formation was best modelled by an approximately second order reaction involving the aromatics.