GB845655A - Multistage fluidized bed reactor - Google Patents

Abstract

In a multi-stage fluidised reactor formed by a series of perforated plates mounted in a vertical column, each plate is provided with <FORM:0845655/III/1> a baffle mounted immediately below it and having perforations off-set from the one in the plate above it. When the fluidising gas is cut off the baffles prevent down-flow of solid. Down comers for the fluidised material may be in the form of tubes passing through both plate and baffle, or formed by an upright plate weir extending above and below the plate and baffle. In the latter form a vertical column 21, Fig. 3, is provided with perforated plates 22 and vertical weirs 24 extending above and below the plate to form a downcomer passage with the remote wall of the column. Below each plate 22 is mounted a baffle 23 having holes offset from the one above it. Preferably the holes in the plates 22 are conical and when air is cut off a small cone of solid forms on the baffle, but does not fall through it. When the gas stream is switched on through ports 27, 28, 29, the layer of solid on the baffle is blown off by jets 45. In a modification, the perforated plate 22 is replaced by a funnel shaped member having a small hole at its base which discharges above a baffle having a weep hole aligned on the axis of the funnel and connected to a fill pipe discharging into another funnel member mounted below it. A downcomer pipe passes through the body of the funnel offset from its axis. The apparatus may be used for treating uranium oxide with HF.