Experimental study of cracking methane by Ni/SiO2 catalyst

Rates of CH4 cracking on a Ni/SiO2 composite catalyst in a flow-through system were determined as a function of a flow rate, the CH4 concentration in carrier, temperature and the amount of carbon deposits. The CH4 decomposition reaction was of the first-order, and its rate constant was independent of the flow rate and the inlet CH4 concentration. Values of the steady-state decomposition rate constant were correlated to kdecomp=3.09×101exp(−29.5[kJ/mol]/RgT) [s−1]. The overall decomposition rate gradually decreased with an increase in the amount of carbon deposits in the catalyst bed. The history of the CH4 decomposition was discussed in terms of an increase in the linear velocity through the bed and an increase in interference with catalytic performance on Ni. Regeneration of the catalyst was compared under two purge gas conditions between H2 and O2. It was found that the H2 purge was more efficient.