Development of a new system for circulating fluidized particles within a single vessel

Abstract A new system for circulating fluidized particles within a single vessel has been developed which has the same advantages as the dual-bed systems widely used for the FCC process and the Fluid Coker process. The interior of the vessel was divided into four sections by intersecting two flat vertical plates at right angles. Two sections were used for the upflowing bubbling fluidized beds and the other two sections were used for the downflowing bubble-free fluidized beds. Fluidized particles were circulated between the two upflowing beds, which were to be used as reactors, through the two downflowing beds, which were to be used as downcomers. Solid particles were fluidized by several streams of gas injected at several stages of the bed. The effects of these gas injection rates on the circulation rate of solids were investigated. The circulation rate of solids was measured using both a measuring box, which collected the overflowing particles, and the downward motion of a gauze net induced by the descending particles. The static pressure distribution within the vessel and the residence time distribution for coarse foreign solids in the system were measured. The present research demonstrated that the proposed system potentially had the same advantages as the conventional dual-bed system, and that the system can be applied to the simple gasification of biomass and solid wastes.