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Effect of catalytic particle clustering on methane steam reforming in a circulating fluidized bed (CFB) reformer is analyzed numerically using a two-dimensional hydrodynamic model coupling with methane steam reforming reaction kinetics. Gas flow fields and distributions of temperature and gas species in a Haldor Topsoe Ni/Mg Al2O4 spinel catalytic particle cluster are predicted. The computed results indicate that the rates of methane steam reaction of a catalyst particle in the cluster are less than that of an isolated catalyst particle out side the cluster. The yields of H2, CO and H2O in the cluster increase with the increase of operating temperature and inlet gas velocity but decrease with the increase of reactor pressure and feed steam.

The burning properties of carbon particles in clusters were numerically studied using a mathematical model. Chemical reactions consist in heterogeneous reactions including char combustion and in gases homogeneous reactions. The numerical model predicted gas flux through a cluster, distributions of gas temperature and concentrations of gas species in clusters. Burnout of char particles in cluster is less than that of isolated char particles in the stream. Formation of NO and N2O are restrained from particle clustering. Effects of inlet gas temperature, inlet gas velocity, distribution of particles in cluster as well as particle size on char combustion and flow behavior are numerically investigated.