Inhomogeneous packed bed burner for improving the utilization of low‐concentration methane

Homogeneous packed bed was usually assumed in the study of porous media combustion. However, the absolute homogeneous structure was impossible in the actual application. In this article, an experimental system was established to study the inhomogeneity of porous media with different diameters and materials of pellets. The effects on the burner temperature, pollutant emissions and start-up characteristics were investigated. Results indicate that the mixed pellets of the three-diameter and four-diameter combinations improved the flame temperature and moved the flame location to the downstream. The CO emission decreased with the increasing of inlet velocity significantly, but the NOx emission increased. For the mixing of zirconia and alumina pellets, the flame temperature was increased and the flame location was close to the outlet with more zirconia pellets. In addition, an orange submerged flame appeared finally compared with the blue flame during the initial ignition of the gas at the surface.