Patent GB-767769-A (GB)
Title: "improvements in a system utilizing a fluidized mass of contact material"
IPC: C10G35/14
Filed: 1954-09-17
Abstract: <PICT:0767769/IV(b)/1> Processes such as the synthesis of hydrocarbons by hydrogenation of carbon oxides; hydrocarbon conversions, e.g. desulphurization, hydrogenation, catalytic cracking, cracking under hydrogen pressure, dehydrogenation &c., and especially hydroforming a light hydrocarbon oil, (i.e. boiling in the gasoline, naphtha and kerosene range) may be performed by contacting the initial gaseous reactant with a fluidized contact material in a reaction zone (6) to produce a gaseous product and thereby contaminate the contact material with a combustible deposit; a portion of the contact material is passed to a stripping zone (10) lying wholly or partly within the reaction zone, and thence via an upflow conduit (24) (to which is supplied an oxygen-containing gas to burn at least part of the combustible deposit) to a regeneration zone (8) directly above the reaction zone wherein said contact material forms a fluidized mass, from which a portion is returned to the reaction zone via a downflow conduit (32).  The use of the illustrated and preferred apparatus is described with respect to the reforming of a naphtha having an average molecular weight of 109.1 using a 9 per cent molybdenum trioxide on alumina catalyst to produce a gasoline with an end point of 400 DEG  F.  The oil feed is supplied at 40 at up to 1000 DEG  F. and hydrogen-containing gas or recycle gas (from product line 65, v.i.) is supplied at 42 to the insulated reactor 6 in which an average temperature and pressure of 940 DEG  F. and 225 p.s.i.g. respectively obtain.  The recycle gas is introduced at a considerably higher temperature than the reaction.  The gaseous reaction product passes through the cyclones shown into a plenum chamber 56 which is said to prevent the formation of a stagnant layer of product vapour in the upper part of the disengaging zone, and emerges by lines 64 and 65.  A catalyst slurry in products of higher boiling range than desired and having an A.P.I. gravity of 43.8 DEG is returned from a recovery system (not shown) to the reaction zone via line 66.  The contaminated catalyst passes through louvres 11 into the stripper 10 where it flows downwardly generally in dense phase against an uprising stream of stripping gas, e.g. steam entering at 600 DEG  F. through line 16, and is then drawn into the conduit 24 by means of air at 280 DEG  F. from line 19 and/or steam from .line 20 at, e.g., 600 DEG  F. which are introduced through valve 15.  Part of the carbon deposit burns and the temperature rises to 1050 DEG  F. and as a result the average temperature in the stripper is 930 DEG  to 945 DEG  F.  The catalyst passes into the regenerator 8 where a temperature and pressure of 1100 DEG  F. and 215 p.s.i.g. respectively are maintained with air from line 82 at 280 DEG  F., cooling tubes 76 being provided for control.  Flue gas discharges from the regenerator via the cyclones shown and line 72 has an average molecular weight of 28. By means of standpipe 32 and a plug valve 34, regenerated catalyst is withdrawn into a well 30 in regulated amount where it is treated at an average temperature of 940 DEG  F. with a hydrogen-containing recycle gas of the same composition as that entering line 42.  The reduced catalyst overflows into the lower part of the reactor.  Contact materials referred to are a refractory such as sand or mullite and a hydroforming catalyst such as compounds of metals of Groups V and VI of the periodic table, especially the oxides and/or sulphides of chromium, molybdenum and tungsten; and these may be supported, e.g. on silica and/or alumina, zinc spinel, bauxite, kieselguhr, pumice, &c.  Also hydroforming may be by means of noble metals, e.g. platinum and palladium supported, if desired, on such carriers as alumina and silica.  The proportion by weight catalytic element/total catalyst may be 0.1 to 25 per cent, preferably (in the case of the former group of elements) 1 to 10 per cent, and (in the case of noble metals) 0.05 to 5 per cent.  Suitable catalyst sizes are not more than 250 microns, generally 10 to 100 microns, and gas velocities may vary between 0.1 and 40, preferably 1 to 2.5 feet per second.  For reforming the temperature and pressure should be 750 DEG  to 1075 DEG  F. (preferably 875 DEG  to 950 DEG F.) and 25 to 1000 p.s.i.g. (preferably 50 to 500 p.s.i.g.) respectively.  For hydroforming, 500 to 15,000, usually 1000 to 7500 standard cubic feet of hydrogen/barrel of oil feed is normally used.ALSO:<PICT:0767769/III/1> A gaseous chemical reactant is contacted with a fluidized contact material in a reaction zone (6) to produce a gaseous product and thereby contaminate the contact material with a combustible deposit; a portion of the contact material is passed to a stripping zone (10) lying wholly or partly within the reaction zone, and thence via an upflow conduit (24) (to which is supplied an oxygen-containing gas to burn at least part of the combustible deposit) to a regeneration zone (8) directly above the reaction zone wherein said contact material forms a fluidized mass, from which a portion is returned to the reaction zone via a downflow conduit (32).  By this means a substantially vertical flow system is achieved and the contact material may be stripped at a higher temperature (e.g. 5 to 15 DEG F. higher) than exists in the reaction zone or-if stripping gas is introduced at a lower temperature than normally used -at normal stripping temperatures, by reason of heat exchange between contact material in the stripper (10) and the conduit (24).  The use of the illustrated and preferred apparatus is described with respect to the reforming of a naphtha using a 9 per cent molybdenum trioxide on alumina catalyst which is supplied at 40 and hydrogen-containing gas or recycle gas (from product line 65, v.i.) is supplied at 42 to the insulated reactor 6. The recycle gas is introduced at a considerably higher temperature than the reaction.  The gaseous reaction product passes through the cyclones shown into a plenum chamber 56 which is said to prevent the formation of a stagnant layer of product vapour in the upper part of the disengaging zone, and emerges by lines 64 and 65.  A catalyst slurry in products of higher boiling range than desired is returned from a recovery system (not shown) to the reaction zone via line 66. The contaminated catalyst passes through louvres 11 into the stripper 10 where it flows downwardly generally in dense phase against an uprising stream of stripping gas e.g. steam entering through line 16, and is then drawn into the conduit 24 by means of air from line 19 and/or steam from line 20 which are introduced through valve 15.  The catalyst after removal of part of the carbon deposit by this means passes into the regenerator 8, air entering from line 82 and cooling tubes 76 being provided for control.  Flue gas discharges from the regenerator via the cyclones shown at 72.  By means of standpipe 32 and a plug valve 34, regenerated catalyst is withdrawn into a well 30 in regulated amount where it is treated with a hydrogen-containing recycle gas of the same composition as that entering line 42.  The reduced catalyst overflows into the lower part of the reactor.