Patent GB-842299-A (GB)
Title: A process involving the treatment of fluid material by contacting it with granular solid material
IPC: B01J8/12
Filed: 1958-05-20
Abstract: <PICT:0842299/IV(b)/1> <PICT:0842299/IV(b)/2> In processes involving the transfer of granular solid material to or from a contacting zone under pressure where the solid is contacted with a fluid material from or to a lower pressure zone, there is maintained a seal leg of compacted solids between the zones of a length such that at the pressure differential fluid material would flow at a rate sufficient to cause boiling of the solids in the lower pressure zone, above the end of the seal leg in the lower pressure zone there is maintained a compact bed of solids having a cross-sectional area greater than the seal leg and sufficient, at a level below the upper surface of the bed, to reduce the velocity of fluid material to below the boiling velocity, solids are continuously removed from the lower pressure zone so that there is continual flow of solids through the seal leg, and solids are supplied to the upper surface of the bed.  In Fig. 1, the reactor 10, e.g. for the catalytic conversion of hydrocarbons, is fed with freshly regenerated catalyst from regenerator 11, operated at a lower pressure than the reactor, by surge hoppers 32 and 35 as described in Specification 732,605 [Group III].  The charge is fed to the centre of the reactor by line 12, together with hydrogen or recycle gas if required, and product removed at each end by lines 14 and 15.  Catalyst is removed from the reactor by passage 16 which forms the seal leg; into this is fed a purge gas at a pressure slightly above that in the reactor to prevent loss of reactants by passage 16.  The seal leg empties into chamber 18 (Fig. 2) which contains a bed of solids of a height sufficient to reduce the velocity of the escaping gases below the boiling velocity below the upper surface of the bed, gases leaving by passage 19 through a filter 42 through which gases but not solids may pass.  Solids are fed onto the top of the bed by passage 25 as described below.  A series of baffles in chamber 18 allow for preferential removal by passage 20 of solids supplied to the chamber by passage 16 while allowing for some movement of the bed above the end of passage 16. Solids removed are transported by conveyer 21, e.g. a bucket elevator or gas lift, to a level above the regenerator whence is falls by gravity through passage 22.  Solids to be supplied to the top of the bed in chamber 18 may be unregenerated solids from passage 22 or regenerated solids from passage 33.  In either case they pass by passage 23, chamber 24 and passage 25.  Chamber 24 is a safety device containing a bed of solids so that should the bed in chamber 18 fail, the gas passes through line 25 and is reduced in velocity by the bed in chamber 24 before passing through exit 43 so that a "blowout" cannot occur.  In an alternative (Fig. 4 not shown) the solids from the seal leg empty into a chamber above the regenerator.  Solids for supply to the top of the bed may in such a case be obtained from the hopper 32 above the reactor or from a hopper positioned above the chamber and supplied by a conveyer from a partial stream withdrawn from the passage between the chamber and regenerator, such hopper having an overflow pipe emptying into the passage leading to the regenerator.  The process may be used in operations where gases, vapours or liquids are contacted with catalytic or inert materials, e.g. in the catalytic reforming of gasolines using a silica-alumina moving bed catalyst under conditions which include; vapour inlet temperature 100-1100 DEG F., catalyst inlet temperature 100-1200 DEG F., space velocity 0,1-6,0 vol/vol/hr., recycle ratio 1-15 mols (1-8 mols H2) per mol. of reactant and pressure 15-600 p.s.i.a.; the regenerator may be operated at 600-1400 DEG F. and 15-600 p.s.i.a.ALSO:<PICT:0842299/III/1> In processes involving the transfer of granular solid material to or from a contacting zone under pressure, where the solid is contacted with a fluid material, from or to a lower pressure zone, there is maintained a seal leg of compacted solids between the zones of a length such that at the pressure differential fluid material would flow at a rate sufficient to cause boiling of the solids in the lower pressure zone, above the end of the seal leg in the lower pressure zone there is maintained a compact bed of solids having a cross-sectional <PICT:0842299/III/2> area greater than the seal leg and sufficient, at a level below the upper surface of the bed, to reduce the velocity of fluid material to below the boiling velocity, solids are continuously removed from the lower pressure zone so that there is continual flow of solids through the seal leg, and solids are supplied to the upper surface of the bed. In Fig. 1, the reactor 10, e.g. for the catalytic conversion of hydrocarbons, is fed with freshly regenerated catalyst from regenerator 11, operated at a lower pressure than the reactor, by surge hoppers 32 and 35 as described in Specification 732,605.  The charge is fed to the centre of the reactor by line 12, together with hydrogen or recycle gas if required, and product removed at each end by lines 14 and 15. Catalyst is removed from the reactor by passage 16 which forms the seal leg; into this is fed a purge gas at a pressure slightly above that in the reactor to prevent loss of reactants by passage 16.  The seal leg empties into chamber 18 (Fig. 2) which contains a bed of solids of a height sufficient to reduce the velocity of the escaping gases below the boiling velocity below the upper surface of the bed, gases leaving by passage 19 through a filter 42 through which gases but not solids may pass.  Solids are fed on to the top of the bed by passage 25 as described below.  A series of baffles in chamber 18 allow for preferential removal by passage 20 of solids supplied to the chamber by passage 16 while allowing for some movement of the bed above the end of passage 16. Solids removed are transported by conveyer 21, e.g. a bucket elevator or gas lift, to a level above the regenerator whence it falls by gravity through passage 22.  Solids to be supplied to the top of the bed in chamber 18 may be unregenerated solids from passage 22 or regenerated solids from passage 33.  In either case they pass by passage 23, chamber 24 and passage 25.  Chamber 24 is a safety device containing a bed of solids so that should the bed in chamber 18 fail, the gas passes through line 25 and are reduced in velocity by the bed in chamber 24 before passing through exit 43 so that a "blow-out" cannot occur.  In an alternative (Fig. 4 not shown) the solids from the seal leg empty into a chamber above the regenerator.  Solids for supply to the top of the bed may in such a case be obtained from the hopper 32 above the reactor or from a hopper positioned above the chamber and supplied by a conveyer from a partial stream withdrawn from the passage between the chamber and regenerator, such hopper having an overflow pipe emptying into the passage leading to the regenerator.  The process may be used in operations where gases, vapours or liquids are contacted with catalytic or inert materials, e.g. in the catalytic reforming of gasolines using a silica-alumina moving bed catalyst under conditions which include; vapour inlet temperature 100-1100 DEG F. catalyst inlet temperature 100-1200 DEG F. space velocity 0.1-6.0 vol/vol/hr., recycle ratio 1-15 mols (1-8 mols H2) per mol. of reactant and pressure 15-600 p.s.i.a.  The regenerator may be operated at 600-1400 DEG F. and 15-600 p.s.i.a.