Expanding the Controllable Range of the Mean Residence Time Ratio of Polydisperse Particles in Multiple-Chamber Fluidized Beds: A Coarse-Grained CFD-DEM Study

The residence time of polydisperse particles is crucial
for their
simultaneous conversion in a fluidized bed. This study focuses on
regulating the residence time of polydisperse particles to expand
their controllable range by optimizing the reactor design and operation
step-by-step. The mean residence time (MRT) ratio of coarse and fine
particles (tpc/tpf) increased significantly with increasing
elutriation pipe width of the multiple-chamber fluidized bed, thus
enabling the MRT ratio to exceed (dpc/dpf)2; however, the MRT ratio of medium and fine
particles (tpm/tpf) is only slightly exceeded dpm/dpf. Moreover, by further optimizing the elutriation
pipe gas velocity, the latter can be adjusted to be exceed (dpm/dpf)1.5. Finally, tpc/tpf and tpm/tpf can be simultaneously adjusted to exceed (dp/dpf)2 by increasing the number of elutriation
pipes. Therefore, present study enables the controllable range of
the MRT ratio of polydisperse particles covering from dp/dpf2 to (dp/dpf)2 that meets the required reaction time ratio
of different particle sizes, which is of great interest for realizing
the synchronous conversion of polydisperse particles.