Kinetic Modeling for Coke Combustion over a Nickel Catalyst Deactivated under Methane Dry Reforming Conditions

This study validates the effectiveness of a composite kinetic processing approach combining the isoconversional method and the master-plot method to determine the kinetic triplet (reaction model, apparent pre-exponential factor, and activation energy) for the nonisothermal combustion at various heating rates of a coked nickel catalyst employed in the dry reforming of methane. First, the average apparent activation energy (164.5 kJ mol^-1) was determined using the Kissinger-Akahira-Sunose (KAS) isoconversional method. Next, the master-plot method was applied to establish the regeneration model function, revealing that the combustion of the carbon nanotubes followed the reaction order model (n = 1.36). The consistency of the regeneration kinetics model was validated by comparing experimental and calculated thermoanalytical curves at a constant heating rate.