A comparison of solids fluxes in a pair of downer and riser reactors

A direct comparison on solids flux was enabled by measurements obtained in a pair of riser and downer circulating fluidized bed reactors, of the same diameter, using suction probes. The operating conditions and the axial posi tion were found to affect the solids flux in each reactor in a different ma nner. The solids flux in the riser were affected to a large degree by the g as velocity, in contrast with the downer where no visible effect was detect ed from changes in the gas velocity. The axial position has an effect on th e shape of the solids flux profiles in the downer, but only small effects w ere observed in the riser. On the other hand, increases in overall solids f lux leads to the increase of local solids flux in both the downer and the r iser.