Mixing Suppression Effect of Large-Hole Perforated Plates in Multi-stage Fluidized Beds

A continuous multi-stage fluidized bed is conventionally constructed with perforated distributor plates and downcomers, which complicates the internal structure and limits the applicable range of particle size and gas velocity. In this study, a punching metal plate with large holes (10 mm in diameter, about 150 times larger than the particle size) and an open area ratio of 23% was employed as the stage plate instead of conventional distributors and downcomers. Tracer experiments demonstrated that the suppression of vertical mixing by the large-hole perforated plate reached approximately 65–85% of that of conventional distributor plates. This finding reveals that even perforated plates with holes much larger than the particle size can provide effective suppression of vertical mixing between adjacent stages. The results indicate that continuous multi-stage fluidized beds can be constructed with remarkably simplified internal structures while maintaining sufficient staging performance, thereby expanding the applicable range of particle size and gas velocity and enabling versatile industrial use.