Apparatus for use in processing a substance in a fluidized bed

Abstract

The apparatus comprises a process vessel, containing a process bed of fluidized particles, having a first submerged port at a first end and a second submerged port at a second end. Both ports are inclined in the same sense so that particles leave the second end of the bed at a higher level than they enter the first end. Fluidized bed material entering the second port becomes defluidized and slides down the port, optionally with the assistance of a fluid injected into the port. The first port conducts particles into the process bed from a second fluidized bed and the second port conducts particles out of the process bed (e.g. into the second bed). The process bed rests on a fluid distributor having a horizontal first part adjoining, and no higher than the level of, the lower end of the first port and a horizontal second part adjoining, and at the level of, the second port, there being a vertical step connecting the first and second distributor parts at a location between the first and second ports. In operation, particles at the bottom layers of the process bed are transferred relatively rapidly from the first port to the second port, while particles at higher levels in the bed have relatively prolonged residence times in the bed.