Patent GB-757986-A (GB)
Title: Improvements in or relating to conveyance of granular solids
Inventor: BERG CLYDE HUET ORVIL
IPC: B01J8/00
Filed: 1952-08-11
Abstract: <PICT:0757986/III/1> <PICT:0757986/III/2> <PICT:0757986/III/3> <PICT:0757986/III/4> <PICT:0757986/III/5> <PICT:0757986/III/6> <PICT:0757986/III/7> <PICT:0757986/III/8> A process for the treatment of a feed fluid with a granular solid comprises contacting the fluid with a moving stream of solid in a contacting zone, withdrawing the solid from one part of the zone, and transferring it to another part through a conveyance zone, through which it would not flow under the influence of gravity alone, by a method which comprises passing a conveyance fluid through a substantially compact bed of solids in the conveyance zone at a velocity sufficient to counteract forces of gravity and friction forces of inner conveyance zone surfaces on the solid particles and moving the compact bed of solids while applying a compacting force to the solids discharging from the outlet of the conveyance zone to maintain the solids in the zone, as well as those at the outlet, at a bulk density substantially equal to the static bulk density of the solids when at rest and thus preventing the solids from fluidization in the conveyance fluid.  The process may be used for moving catalysts in catalytic cracking, hydrogenation, hydrodesulfurization, oxidation and other known catalytic processes, the conveyance of sand from tarsand retorting processes, movement of ores and coal in metallurgical operations or handling granular solids in industrial and agricultural operations.  Fig. 1 shows an apparatus for the conveyance of granular adsorbent charcoal from the bottom to the top of a selective adsorption column.  The charcoal flows through pipe 10, pressuring means 11 and pipe 12 into a cylindrical vessel 13 forming the induction zone at the foot of the lift line 14. The pressuring means 11 is designed to allow the passage of charcoal from a region at low pressure to one at high pressure without a reverse flow of gas.  The end of the lift line 14 extends into the charcoal 15 and has a reduced part 20 for restricting the entry of the material.  The lifting gas enters the vessel 13 through a pipe 21 controlled by valves 22, 23, the latter of which may be actuated either by differential pressure recorder controller 24 in accordance with the differential pressure across the lift line or by the adsorbent level controller 25 in accordance with the level 19 of the charcoal. The lift line terminates at its upper end in a separator 16 containing a thrust plate 17.  This plate maintains the charcoal in a substantially compact state and prevents fluidization. Lifting gas is disengaged from the charcoal and discharged through a pipe 27 controlled by valve 28 to a separator 29 where charcoal fines are removed.  The gas then passes through the pipe 30 to a compressor where its pressure is raised before reintroduction into the vessel 13.  Alternatively, the gas passes from the separator through the outlet 18 containing charcoal into the upper part of adsorption column 31.  The downwardly moving charcoal is directed by a baffle 32 into a tube 33 which passes into the central aperture of an elutriation tray 35.  The charcoal here meets the upwardlyflowing purge gas and the fines are carried away by it through the pipe 40. The particles having the desired size range accumulate in the storage zone 36.  The expansion of the lifting gas which occurs in the lift line is counteracted by increasing the cross-sectional area of the line 52, Fig. 2, in the direction of flow.  Supplemental conveying fluid is supplied to ring manifolds 64, 65, 66 which communicate with the line 52 by pipes 67, 68, 69.  The supply of fluid to the rings through inlets 70, 71, 72 from a manifold 73 is regulated by valves 74, 75, 76 which are controlled by differential pressure controllers 77, 78 79.  Each controller is actuated by the pressure differential existing through a zone adjacent the point of introduction of the fluid.  The expansion of the gas may be counteracted also by removal of a part of it at the chamber 133, Fig. 4, connecting the lower and upper parts 131, 132 of the lifting line.  This chamber has a transverse disengaging tray from which a part of the fluid is removed through the pipe 135 controlled by valve 136.  The gas passes from this pipe to a cooler and dust remover 145 from which it passes to an interstage of a multi-stage compressor 147.  Here gas from the first stage of the compressor joins it and the high pressure gas passes through the pipe 149 into the surge chamber 150 from which it passes through the pipe 151 into the high pressure manifold 119 leading to induction chamber 108.  In the construction shown in Fig. 5, the lifting line consists of sections 161, 162 connected by an expansion fitting 163.  The upper section 162 has openings 180 formed in it just below the point of discharge through which fluid can pass to a pipe 181.  In the construction shown in Fig. 6, the thrust plate is dispensed with and a counterthrust is produced by a static bed of solids 200.  The separator 190 has an expansion chamber surrounding the end of the lifting line 193. Variable orifices 197 control the discharge through the pipes 196. The induction chamber 210, Fig. 7, is connected to the lifting pipe 214 by a U-shaped pipe 212 of diminishing cross-section and a pipe 213 of increasing cross-section. Between the chamber and the pipe 212 is a short pipe 211, the length of which is at least equal to its diameter and preferably is not greater than five diameters.  A form of pressuring device shown in Fig. 8 consists of a vessel 225 provided with an upper surge chamber 226, primary pressuring chamber 227, secondary pressuring chamber 228 and a lower surge chamber 229.  Solids pass through pipe 230 on to a movable plate 231 in the chamber 226 over which they flow.  The plate is raised and lowered automatically by means 232, 233 actuated in accordance with a flow control instrument.  A sloping baffle 240 leads the solids to outlets 238, 239 which open into chamber 227, 228 and are opened and closed by slide valves S1, S3.  These valves are actuated by pneumatic cylinders 241, 242 so that one is open when the other is closed. The outlets 250, 251 from the chamber 227, 228 are controlled by valves S2, S4 actuated similarly to the valves S1, S3 but timed so that the valves S2, S4 are open when the valves S1, S3 are closed.  Gas risers 243, 244, 252, 253 are provided within the outlets to allow sufficient gas to flow to equalize any small pressure differences between the chambers.  High pressure conveyance fluid is introduced into the chamber 229 through the pipe 258.  The level 261 of the solids in this chamber is measured by grid work 260 depending from a horizontal bar 262 which is attached at right angles to a tube capable of supporting a torsional stress and contained in a tubular housing 263.  The movement of the torsion tube actuates the level controller.  Apparatus for the circulation of catalyst in a hydrocarbon conversion process is shown in Fig. 9.  Naphtha supplied through pipe 275 is pumped through pipe 277 by a pump 276 which raises its pressure to 490 lbs. per square inch.  The rate of flow through pipe 277 is controlled by valve 278 in accordance with flow recorder controller 279.  The naphtha passes to a heat exchanger 280 where its temperature is raised by the effluent from the reactor to 300 DEG F.  It then passes to a second heat exchanger 282 in which it is heated to 475 DEG F. and then passes to a vaporizing coil 284. The vapour passes through the pipe 287 and is injected into the reactor column 288.  Cobalt molybdate moves downwards by gravity as a continuous compact unfluidized bed in the reactor 288 and regenerator 289 and is carried through the connecting pipes 290, 291 by fluid. Regenerated catalyst passes out of the regenerator through pipe 292 into pressuring chamber 294 where the pressure is raised from 318 to 575 lbs. per square inch by steam.  The pressured solid then flows through pipe 296 into regenerated catalyst induction zone 298 where more steam is supplied.  The steam and catalyst pass up through the pipe 291 into chamber 300 where resistance is applied to the flow of solids from the pipe 291 to maintain them during conveyance in substantially compact and unfluidized form at the same density as the solids flowing in column 289.  The regenerated catalyst and steam pass into separator zone 302 where part of the steam is removed through pipe 303.  The catalyst and the remainder of the steam pass through a series of pipes 304 into the top of reaction vessel 288 down which the catalyst passes by gravity as a compact unfluidized moving bed through reduction gas engaging zone 305, catalyst reduction zone 306, reactor effluent disengaging zone 307, reaction zones 308, 310, 312, 314, 316, sealing and vapour disengaging and engaging zone 309, 311, 313 and then through reactor feed engaging zone 317, recycle gasengaging zone 319, catalyst stripping zone 320 and stripping gas engaging zone 321 to a reciprocating feeder 322. The catalyst passes from the bottom of the reactor 288 through the pipe 290 to a reversing chamber 325 from which it descends through the pipe 326 to a flow control valve superstructure 327 leading to a chamber 330.  This chamber contains a funnel 331 through which the catalyst flows.  The valve stem 329 passes through the funnel and carries a plate 332 which can close the outlet 333.  Part of the depressured conveying fluid passes out through the pipe 335.  The catalyst falls as a shower in uncompacted form through elutriation zone 337, the lower end of which is at a higher pressure than the zone 336.  Catalyst fines are swept out in suspension through the pipe 338.  The elutriated spent catalyst passes through pipe 339 into regeneration vessel 289 to which flue gas and air are admitted through pipes 341, 342 and the deactivating deposit is burned. Recycle gas containing 65 per cent of hydrogen