Patent GB-723489-A (GB)
Title: Improvements in or relating to fluidised hydroforming
IPC: C10G35/14
Filed: 1952-10-14
Abstract: Hydrocarbons boiling within the motor fuel boiling range are hydroformed by contacting the hydrocarbons in a reaction zone under hydroforming conditions with a dense fluidized bed of hydroforming catalyst particles and continuously introducing into the top of the said reaction zone a stream of hot, inert, solid particles which are maintained in a fluidized <PICT:0723489/IV (b)/1> state therein, whereby the upper parts of the said reaction zone are maintained at a higher temperature than the lower parts thereof, removing spent catalyst particles from the said reaction zone and also removing the said inert solid particles from the bottom of the said reaction zone, mixing the removed inert solid particles with the removed spent catalyst particles and transferring the mixture thus obtained to a regeneration zone wherein the spent catalyst particles are regenerated and the inert solid particles are heated by the heat of regeneration of the catalyst particles, removing regenerated catalyst particles and recycling them to the said reaction zone, and removing hot inert solid particles and recycling them to the top of the said reaction zone.  In the Figure, fresh feed or charging stock which may be a virgin naphtha, cracked naphtha or Fischer-Tropsch naphtha having a boiling range of 130-430 DEG  F. is supplied under pressure and preheated to a desired temperature through line 12 to distributer nozzles 13 in the lower portion of the reactor vessel 10.  Catalyst mixed with a small amount of inert heat transfer solids is supplied to the reactor in finely-divided form in suspension in a hydrogen-rich gas, preferably recycle gas, through line 14 and a perforated plate or grid 16 whilst a stream of hot inert solids containing a small amount of catalyst particles is discharged through line 60 against baffle 62 from which they drop into the upper part of the reactor dense bed.  Means such as one or more perforated grids 63 or plates and downcomers may be provided to prevent rapid dispersal of the solids into the main fluidized body of solids in the reactor. Typical inert solids which may be used are metal spheres or ceramic balls or granules preferably of corundum, gamma alumina, or fused silica and unless the solids have a bulk density at least 1.5 times that of the catalyst they should be no smaller than 100 microns diameter and should preferably be of 125-300 microns diameter.  The velocity of the feed gas should be sufficient to maintain a dense turbulent fluidized bed 18 of catalyst and inert solid particles. The dense fluidized bed of solid particles has a definite level L with a dilute phase suspension of solids and product vapours 20 above it. The vaporous reaction products must pass through the zone 19 which is at a higher temperature, e.g. 50 DEG  to 100 DEG  F. higher, than the average temperature in the bed 18 and pass through a cyclone separator 31, the separated catalyst particles being returned to the dense bed by the dip pipe shown.  The catalyst particles are withdrawn from the dense bed 18 through pipe 23 into a vertical conduit 22 in which the catalyst is stripped with steam or other stripping gas introduced through line 24.  The inert heat-transfer solids mixed with finely divided catalyst particles are withdrawn through line 33 into chamber 34 where they are treated with steam or other inert gas for effecting separation of finely divided catalyst particles from the heat-transfer solids, the catalyst particles passing into the upper part of the reactor 10.  The inert heat-transfer solids admixed with a small amount of catalyst particles then pass through conduit 37 into transfer line 30 where they are picked up by a stream of regeneration air and mix with the main stream of catalyst particles, the mixture being discharged into inlet chamber 41 covered by a plate or grid in regenerator 40 to form a dense fluidized bed of catalyst having a definite level L1 in the regenerator.  The superficial velocity of the regeneration gas through the regenerator may range from 0.3 to 1.5 feet per second depending on the pressure, e.g. it should be 1.0 foot per second or lower at regeneration pressures of 200-300 pounds per square inch. Torch oil or gas may be supplied to a nozzle 44 to heat the mixture of catalyst and inert solids to the desired temperature.  The regenerated catalyst particles are then passed through pipe 46 to a conduit 45 where they are stripped with air or other inert stripping gas and then pass into standpipe 48 where further stripping may be effected by introducing nitrogen or other inert gas through inlet line 49. The stripped regenerated catalyst particles mixed with some inert heat transfer solids are then discharged into transfer line 14 where they are picked up by a stream of recycle gas and conveyed back to the reactor.  A mixture of inert heat-transfer solids and catalyst particles is withdrawn through well 52 into elutriating chamber 54 into which air or inert gas is introduced through inlet 55 to effect separation of finely divided catalyst particles from the heat-transfer solids, the latter mixed with a small amount of catalyst being discharged into standpipe 57 where they may be purged with nitrogen or other inert stripping gas introduced through line 58.  The solids then pass into line 60 into which a stream of recycle gas is introduced to convey the hot inert solids mixed with a small amount of catalyst into the upper part of the reactor 10.  The feed stock to the hydroforming reactor is preheated alone or in admixture with recycle gas from 500 DEG  to 1000 DEG  F., preferably 600 DEG to 900 DEG  F.  The recycle gas which contains 50 to 70 volume per cent hydrogen is preheated to 800 DEG  to 1200 DEG  F., preferably below 1000 DEG  F., and should be circulated through the reactor at about 1000 to 8000, preferably 1000 to 3000, cubic feet per barrel of naphtha feed.  Suitable hydroforming catalysts include Group VI metal oxides such as molybdenum oxide, chromium oxide or tungsten oxide, or mixtures thereof, upon a carrier such as activated alumina or zinc aluminate spinel.  Promoters such as silica, calcium oxide, ceria or potassia can be included in the catalyst.  The hydroforming should be conducted at 850 DEG  to 925 DEG  F. and at a pressure of 50 to 500 pounds per square inch and the regenerator is operated at essentially the same pressure as the reactor vessel and at temperatures of about 1050 DEG  to 1200 DEG  F.  The weight ratio of catalyst to oil introduced into the reactor should be 0.1 to 5.0, preferably 0.3 to 1.  Space velocity (weight in pounds of feed charged per hour per pound of catalyst in the reactor) for a molybdenum oxide on alumina gel catalyst may vary from about 1.5 to about 0.15 wt./hr./wt.  The weight ratio of inert solids to catalyst circulated from the reactor to the regenerator may vary from about 1 to 100 depending on the relative amount of heat provided by the naphtha and recycle gas streams as compared to that supplied by the circulating solids.ALSO:<PICT:0723489/III/1> Hydrocarbons boiling within the motor fuel boiling range are hydroformed by contacting the hydrocarbons in a reaction zone under hydroforming conditions with a dense fluidized bed of hydroforming catalyst particles and continuously introducing into the top of the said reaction zone a stream of hot, inert, solid particles which are maintained in a fluidized state therein, whereby the upper parts of the said reaction zone are maintained at a higher temperature than the lower parts thereof, removing spent catalyst particles from the said reaction zone and also removing the said inert solid particles from the bottom of the said reaction zone, mixing the removed inert solid particles with the removed spent catalyst particles and transferring the mixture thus obtained to a regeneration zone wherein the spent catalyst particles are regenerated and the inert solid particles are heated by the heat of regeneration of the catalyst particles, removing regenerated catalyst particles and recycling them to the said reaction zone, and removing hot inert solid particles and recycling them to the top of the said reaction zone.  In the figure, fresh feed or charging stock which may be a virgin naphtha, cracked naphtha or Fischer-Tropsch naphtha having a boiling range of 130-430 DEG F. is supplied under pressure and preheated to a desired temperature through line 12 to distributer nozzles 13 in the lower portion of the reactor vessel 10. Catalyst mixed with a small amount of inert heat transfer solids is supplied to the reactor in finely-divided form in suspension in a hydrogen rich gas, preferably recycle gas, through line 14 and a perforated plate or grid 16 whilst a stream of hot inert solids containing a small amount of catalyst particles is discharged through line 60 against baffle 62 from which they drop into the upper part of the reactor dense bed.  Means such as one or more perforated grids 63 or plates and downcomers may be provided to prevent rapid dispersal of the solids into the main fluidized body of solids in the reactor.  Typical inert solids which may be used are metal spheres or ceramic balls or granules preferably of corundum, gamma alumina, or fused silica and unless the solids have a bulk density at least 1.5 times that of the catalyst they should be no smaller than 100 microns diameter and should preferably be of 125-300 microns diameter.  The velocity of the feed gas should be sufficient to maintain a dense turbulent fluidized bed 18 of catalyst and inert solid particles.  The dense fluidized bed of solid particles has a definite level L with a dilute phase suspension of solids and product vapours 20 above it. The vapours reaction products must pass through the zone 19 which is at a higher temperature e.g. 50-100 DEG F. higher than the average temperature in the bed and pass through a cyclone separator 31, the separated