GB1365100A - Method of removing fragments accumulated in fluidized beds - Google Patents

Abstract

1365100 Removing fragments from fluidized beds NIPPON KOKAN KK and D KUNII 29 Dec 1971 [28 Dec 1970] 60587/71 Heading B2H , In a fluidized bed process in which hot gas is passed upwardly through the bed, fragments, e.g. of composite pellets composed of iron ore fines and a reducing agent, are removed from the bed by allowing the fragments to flow into an overflow pipe, the inlet of which is arranged near the top surface of the bed, the fines produced by abrasion in the bed, being entrained in the hot gas. In Fig. 1, a reaction vessel 1 contains a fluidized bed 12 through which hot gas is passed upwardly. Unreacted pellets are fed to the bed from a hopper 5 by means of feed means 6. During fluidizing, fine particles of ore produced by abrasion in the fluidized bed are removed by the hot gas flow in the direction of the arrow. Fragments of the pellets, produced by thermal or mechanical shock and too large to be removed by the gas flow, accumulate in the upper part of the bed and are removed continuously through an overflow pipe 7 provided with a control valve 8 and pass to a receiver 9. In a modification, the pipe 7 incorporates a valve arranged at its inlet so that removal of the fragments can be effected as and when necessary. In a further modification, the overflow pipe with a closable inlet valve projects through the wall of the vessel into the upper part of the bed. In a still further modification, the overflow pipe, again with a closable inlet valve, is arranged axially within the reaction vessel.