Kinetic Studies on Catalytic Decomposition of Methane to Hydrogen and Carbon over Ni/TiO₂ Catalyst

Experiments were conducted in a fixed-bed catalytic reactor to study the decomposition of methane to hydrogen and carbon over 13 wt % Ni/TiO 2 -based catalyst. The variables include the volumetric flow rate of reactant (relative partial pressures of methane and argon of 0.5 each) (100 < v 0 < 450 mL/min) and reaction temperature (823 < T < 1173 K). The experimental data of conversion versus time were subjected to the integral method of analysis, and the rate law of the decomposition reaction was found to be first-order. An activation energy of 60 kJ/mol was obtained. A possible reaction sequence for methane decomposition was validated against experimental data. An analysis of the rate equations indicated that the adsorption of methane on the surface is the rate-controlling step. This observation was same as that obtained from an analysis of data by both integral and differential methods. Using the design equation for a packed plug-flow reactor, predictions were made to obtain the conversion profiles at various operating conditions. Good agreement was obtained upon comparison of the experimental and simulated data.