GB787575A - Improvements in or relating to process for the treatment of platinum catalyst - Google Patents

Abstract

<PICT:0787575/IV (b)/1> Supported platinum catalyst which has become contaminated with carbonaceous deposits during the hydroforming at 900-1000 DEG F. of a naphthenic feedstock of boiling range 150-500 DEG F. is regenerated with an oxygencontaining gas at a temperature not exceeding 1100 DEG F. and then cooled by from 150-300 DEG F., the cooling taking place in the presence of an oxygen-containing gas having an oxygen partial pressure of at least one atmosphere. For pressures of 200-400 p.s.i.g., this oxygen partial pressure corresponds to 3.5 to 7 per cent by volume of oxygen or more. The catalyst support may be alumina (e.g. gamma alumina derived from boehmite), zirconia, magnesia, or magnesia-alumina. Hydroforming pressures may be 50-700 p.s.i.g. As shown in Fig. 1, hydrogen and vaporized feed pass through pipe 20 into a fluidized bed of catalyst in reactor 11, the product being withdrawn through pipe 21. Catalyst for regeneration is carried by flue gas through pipe 14 to regenerator 12; air, which may be mixed with flue gas or oxygen, is fed in at 50. Catalyst leaving the regenerator is treated in pipe 15 with gas introduced through pipe 54; this gas has an oxygen partial pressure of at least one atmosphere and a temperature of 1050-1100 DEG F. The catalyst is then cooled to 800-900 DEG F. in vessel 56 in the presence of a gas of similar oxygen partial pressure, oxygen is removed by stripping in vessel 18 with flue gas, nitrogen, or carbon dioxide, and the regenerated catalyst is mixed with the feed in pipe 20. The treatment in pipe 15, cooler 56, and stripper 18 may be carried out on only a portion of the catalyst, the remainder being returned directly to the reactor; alternatively, the treatment may be given only after several reaction and regeneration cycles. In fixed bed operation, Fig. 2 (not shown), two catalyst bed-are provided and are used alternately, regeneration being carried out by purging with flue gas at 600-1000 DEG F., adjusting the temperature of the gas to 700-800 DEG F. and then adding an oxygen-containing gas to the flue gas to burn off carbonaceous matter. The oxygen content of the flue gas is then increased to provide a partial pressure of at least one atmosphere and the temperature is increased to 1050-1100 DEG F. Cooling is effected by reducing the temperature of the gas to 800-900 DEG F. and then flue gas is used to purge oxygen from the bed. After passage of a hydrogen-containing gas, the bed is ready for re-use. In another embodiment, oxygen at 35-45 lbs. per square inch absolute is passed over the regenerated catalyst first at 1100 DEG F. and then at 800 DEG F.; nitrogen is used for purging the catalyst.ALSO:<PICT:0787575/III/1> Supported platinum catalyst which has become contaminated with carbonaceous deposits during the hydroforming at 900-1000 DEG F. of a naphthenic feedstock of boiling range 150-500 DEG F. is regenerated with an oxygen-containing gas at a temperature not exceeding 1100 DEG F. and then cooled by from 150-300 DEG F., the cooling taking place in the presence of an oxygen-containing gas having an oxygen partial pressure of at least one atmosphere. For pressures of 200-400 p.s.i.g., this oxygen partial pressure corresponds to 3.5 to 7 per cent by volume of oxygen or more. The catalyst support may be alumina (e.g. gamma alumina derived from boehmite), zirconia, magnesia, or magnesia - alumina. Hydroforming pressures may be 50-700 p.s.i.g. As shown in Fig. 1, hydrogen and vaporized feed pass through pipe 20 into a fluidized bed of catalyst in reactor 11, the product being withdrawn through pipe 21. Catalyst for regeneration is carried by flue gas through pipe 14 to regenerator 12; air, which may be mixed with flue gas or oxygen, is fed in at 50. Catalyst leaving the regenerator is treated in pipe 15 with gas introduced through pipe 54; this gas has an oxygen partial pressure of at least one atmosphere and a temperature of 1050-1100 DEG F. The catalyst is then cooled to 800-900 DEG F. in vessel 56 in the presence of a gas of similar oxygen partial pressure, oxygen is removed by stripping in vessel 18 with flue gas, nitrogen, or carbon dioxide, and the regenerated catalyst is mixed with the feed in pipe 20. The treatment in pipe 15, cooler 56 and stripper 18 may be carried out on only a portion of the catalyst, the remainder being returned directly to the reactor; alternatively, the treatment may be given only after several reaction and regeneration cycles. In fixed bed operation, Fig. 2 (not shown), two catalyst beds are provided and are used alternately, regeneration being carried out by purging with flue gas at 600-1000 DEG F., adjusting the temperature of the gas to 700-800 DEG F. and then adding an oxygen-containing gas to the flue gas to burn off carbonaceous matter. The oxygen content of the flue gas is then increased to provide a partial pressure of at least one atmosphere and the temperature is increased to 1050-1100 DEG F. Cooling is effected by reducing the temperature of the gas to 800-900 DEG F. and then flue gas is used to purge oxygen from the bed. After passage of a hydrogen-containing gas, the bed is ready for re-use. In another embodiment, oxygen at 35-45 lbs. per sq. inch absolute is passed over the regenerated catalyst first at 1100 DEG F. and then at 800 DEG F.; nitrogen is used for purging the catalyst.