Patent GB-774515-A (GB)
Title: Process for catalytic reforming of hydrocarbons
IPC: C10G35/14
Filed: 1953-04-17
Abstract: <PICT:0774515/IV(b)/1> The invention comprises a catalytic reforming process wherein a particle-form catalyst containing more than 0.5 weight per cent loosely bound water and/or oxygen moves downwardly through a reforming zone as a compact bed, and hydrocarbon feed vapours to be reformed are contacted with said catalyst bed in said zone under reforming conditions and in a manner such that at least a portion of said vapours flow upwardly countercurrent to said downwardly moving compact bed, characterized by temperatures in the top 20 to 30 volume per cent of the catalyst bed contiguous to the catalyst inlet to said zone which are high enough to reduce the loosely bound water and/or oxygen content of the catalyst leaving the said 20 to 30 per cent of the catalyst bed to below 0.5 per cent and which are not less than <FORM:0774515/IV(b)/1> where T is the catalyst residence time in minutes in the said 20 to 30 volume per cent of the said catalyst bed.  The ratio of the vapour stream heat capacity, i.e. the product of the pounds of vapour per hour fed to the reactor and its specific heat, to the catalyst stream heat capacity, i.e. the product of the pounds of catalyst per hour fed to the reactor and its specific heat, are preferably adjusted so that the average catalyst temperature in the lower 97 volume per cent of the catalyst bed through which the feed vapours flow upwardly is not lower than about 5 DEG  F. below the temperature of the vapour surrounding the catalyst.  Also, the ratio of the vapour stream heat capacity to the catalyst stream heat capacity for catalyst inlet temperatures less than 800 DEG  F. should be at least 1.25 and for catalyst inlet temperatures greater than 800 DEG  F, it should be at least 0.02.  The catalyst residence time in said 20 to 30 volume per cent of catalyst is preferably less than about 60 minutes.  The invention may be applied to the conversion of a virgin Columbian naphtha (boiling range 200-400 DEG  F.) in the presence of a particle-form solid reforming catalyst comprising at least about 70 mols. per cent alumina and about 18 to about 30 mols. per cent chromia and containing more than 0.5 weight per cent, e.g. 1.5 weight per cent, loosely bound water and/or oxygen in the presence of a gaseous heat carrier which is preferably a recycle gas comprising at least about 25 per cent, e.g. about 35 to 60 per cent, by volume of hydrogen and the balance C1 to C6 hydrocarbons and the catalyst may pass through a plurality of reaction zones in a single reactor or through a plurality of reactors in series.  A table is given to show the preferred operating conditions which may be employed in the process.  The Figure illustrates a single reactor which will provide a plurality of zones of adjustable catalyst bed depth, the reactor 1 being provided with a plurality of distributers 3, 4, 5, 6, 7, 8, 9 and 10.  When only one charge stock is to be reformed only one of the distributers is required but when two different charge stocks are treated simultaneously two distributers are required the distributer or distributers being chosen on the basis of the severity of reforming conditions to which the stock or stocks are to be subjected to obtain reformates of required octane rating. The charge stock is heated to such a temperature that when mixed with a gaseous heat carrier, e.g. with about 4 to 10 mols. gaseous heat carrier per mol. of hydrocarbon charge stock, the temperature of the charge mixture is about 800 DEG  to 1180 DEG  F., e.g. about 900 DEG  to 1060 DEG  F. The heated charge mixture flows through either line 16 to one of the distributers 3, 5, 7 and 9 or through line 17 to one of the distributers 4, 6, 8 and 10.  When two different charge stocks are to be reformed the heated charge mixture containing the first charge stock flows through line 16 or 17 to one of the respective distributers while the second charge mixture containing the second charge stock flows through the other line to a distributer adjacent to the chosen distributer for the first charge stock.  Distributers 5 and 6 can be used to divide the reactor into a reaction zone A formed between distributer 5 and collector 12 and a second reaction zone B formed between distributer 6 and collector 13.  By settling throttling devices 14 and 15 to provide given space velocities in respective zones the severity of the reforming conditions in each zone can be controlled to yield reformates of the same or different octane ratings.  The catalyst flows downwardly through inlet 2 and reactor 1 and is removed through outlet 11 operated in conjunction with a suitable particle-form catalyst transfer and reactor sealing means.  The catalyst may be reactivated by burning off the deposited coke in a stream of air in a regenerator or kiln to which it passes through conduit 11 and is then returned to the reactor.