Investigation of low concentration methane combustion in a fluidized bed with Pd/Al2O3 as catalytic particles

Abstract

The catalytic combustion characteristics of low concentration (0.15–3 vol%) methane combustion in a lab-scale fluidized bed with 0.5 wt% Pd/Al₂O₃ as catalytic particles were studied experimentally. A mathematical model was developed according to the flow and reaction characteristics of the fluidized bed. The effects of bed temperature and inlet methane concentration on combustion were investigated and the kinetic characteristics were analyzed. The results show that methane conversion increases with increasing bed temperature, while it decreases slightly as the inlet methane concentration increases. The reaction order was evaluated as 0.608, and the activation energy was determined to be 96 185 J mol⁻¹ during low-concentration methane catalytic combustion in the fluidized bed. It was also found that the reaction in the fluidized bed was controlled by kinetics when the temperature was below 450 °C. When the temperature exceeded 450 °C, the reaction kinetic constant increased with increasing temperature, and the reaction was eventually controlled by kinetics, mass transfer and diffusion. A comparison of the results showed that the values calculated by the mathematical model agreed well with the experimental data.