GB665472A - Improvements in or relating to the contacting of gases with finely divided solids - Google Patents

Abstract

<PICT:0665472/III/1> <PICT:0665472/III/2> <PICT:0665472/III/3> A reactor suitable for hydrocarbon cracking operation and for contacting gaseous or vaporous materials in general, with fluidized finely divided solids, particularly catalysts, is provided with a plurality of elongated stripping zones in parallel, each zone containing a flow reducing means adapted to produce a pressure drop of 0.1 to 5 per sq. inch thereacross, whereby the flow of solids through the zones is equalized. The flow restricting means may comprise an orifice plate 37, Fig. 1, placed at the outlet of each of a plurality of parallel stripping zones 26 provided with baffles 36, or alternatively the orifice may be placed at the entrance of each stripping zone as in Fig. 7, where an annular space surrounding the reaction chamber is split by vertical radial partitions into a number of stripping zones 128 provided with baffles 138, 139. The flow of solids to the individual zones is restricted by the orifices 135 which provide the necessary pressure drop. Stripping steam enters through pipes 137 optionally fitted with jets 140 and the wall 129 of the stripping zone extends well above the dense phase bed level 121. In this reactor dual feed pipes 111 for the solid and fluidizing gases are provided and dual cyclone separators 123 separates the entrained solids from the effluent gases; the return pipes 124 are provided with valves 125 and fluidizing steam pipes 126. Fig. 9 shows a modification where the flow-restricting orifice is formed between the inner wall 161 of the stripping zone and an inclined plate 160, the upper part of which may be extended parallel to the reactor wall to provide a disengaging space with stripper gas outlet above the level 163 of the fluidized bed. According to an example, gas oil is passed in vapour form together with a silica/alumina or silica/magnesia catalyst to a reaction chamber as shown in Fig. 1 at 800-1100 DEG F, the catalyst/oil ratio varying between 5:1 and 30:1 by weight.