Combustion of Low-Concentration Coal Bed Methane in a Fluidized Bed

Low-concentration coal bed methane combustion tests were carried out in a bubbling fluidized-bed reactor with a mixture of limestone and crushed catalyst as bed material. The effects of bed temperature (723-923 K), inlet methane concentration (0.15-3 vol %), and superficial velocity (0.1-0.25 m/s) on methane conversion were studied. Gas was sampled from the bed and the freeboard to analyze the axial profiles of methane in the reactor. With kinetic parameters obtained in a fixed-bed microreactor, predictions from a two-phase model were compared to the experimental data from the fluidized bed. The results showed that bed temperature greatly affected the conversion, with a higher methane conversion obtained by increasing the temperature, reducing the inlet methane concentration, and decreasing the superficial gas velocity.