GB773421A - Liquid-granular solids contacting - Google Patents

Abstract

<PICT:0773421/III/1> <PICT:0773421/III/2> The continuous treatment of water with granular zeolites and the liquid phase conversion of hydrocarbons in the presence of either inert or catalytic granular materials are two of the processes to which the invention shown may be applied, and it is described in connection with the decolorizing of oil with e.g. fuller's earth. Hydrocarbon oil, optionally pre-heated, is introduced at 14 to a treating vessel 12, Fig. 1, and withdrawn at 15 while regenerated fuller's earth is introduced at 10 and withdrawn, contaminated, at 18. The adsorbent is present in the regions 17, 18 and 19 as a continuous phase, thus acting as a seal against excessive liquid flow. It is transported up a pipe 20 by some of the charge liquid introduced at 21, and is discharged therefrom along that one of a number of pipes 22 which is open, or along the lowest if more than one is open. The choice of pipe 22 determines the difference in height between the liquid level 16 in the treating zone 12 and the height to which the suspension rises in the transport pipe 20 and thus determines the rate of withdrawal of adsorbent from the zone 12. The adsorbent is cooled by wash solvent introduced at 24a and washed in a vessel 25 by further solvent introduced at 27 and withdrawn at 28 to a fractionater 29. The adsorbent is withdrawn from the washer 25 in the same manner as from the treating zone 12 and passes to a fluidized-bed drier 40 to which steam is supplied at 41. Heat-transfer coils may be incorporated. Solvent-steam mixture is withdrawn at 44 and condensed at 45, solvent returning to a tank 26. Dried adsorbent passes at 47 to a regenerator such as a kiln. From the fractionater 29 condensed solvent is returned to the tank 26 while oil is recycled at 33. In the washer 25 of Fig. 2 no transport liquid is introduced at the bottom of the seal column 34, as it is in Fig. 1; instead, the column 34 is made wide enough to permit liquid from it to pass with the adsorbent up transport pipe 36. The solvent-adsorbent mixture eventually falls on to a rotating screen 49 whence adsorbent is scraped at 53 while solvent is removed at 51. The rate of solids withdrawal is adjusted to maintain a constant bed level: the bed level may be ascertained by a device shown in Fig. 2. The solids entering at 24 pass through a funnelshaped member 58 into a receptacle 60 supported by a rod 62 co-operating with a scale 63. The upper end of the columnar mass is situated within the receptacle 60; the weight of the receptacle 60 and the solids therein is constantly recorded by scale 63 and is a measure of the height of the solids. Specification 711,487 is referred to.