Stability analysis of perforated plate type single stage suspension fluidized bed without downcomer

The stability of operation of a perforated plate type suspension bed withou t downcomer was analyzed experimentally and numerically. The effects of the feed rate, the gas flowrate and the opening ratio and hole dia meter of th e perforated plates on the operating stability of the fluidized bed were ex amined. A full three-dimensional discrete particle simulation method propos ed by Tsuji [1993] was performed to study the formation of a stable suspens ion fluidized bed. The course and behavior of particles that formed a dense and stable fluidized bed are discussed. Both the experimental and simulati on results of this study show that the process of forming a suspension bed can be categorized into (i) an induced stage, (ii) a growing stage, and (ii i) a stable stage. The velocity of gas through the orifice directly control s the formation of the bed while the solid now rate over a considerable ran ge maintains a balanced hold-up in the suspension bed system without downco mers. The existence of a multiplicity of steady states corresponding to dif ferent gas flow rates, for the same feed rate and perforated plate type, wa s observed. Results show that the design of the plate, the particle feed ra te and the gas velocity distribution through the hole affect the stability of the fluidized bed. The simulated results agree qualitatively well with e xperimental observations.