Hydrocracking process with reactivated catalyst
AssigneeUnion Oil Company of California
InventorJohn W. Ward
Life of this patent
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Abstract
Deactivated Group VIII noble metal-Y zeolite hydrocracking catalysts are reactivated by oxidative combustion to remove coke deposits, followed by treatment with aqueous ammonia to redistribute agglomerated noble metal, followed by calcination in a critical temperature range between about 600.degree. and 850.degree. F. The low-temperature calcination results in reactivated catalysts of improved activity, particularly for hydrocracking feedstocks substantially free of nitrogen compounds.
Claims14
A hydrocracking process which comprises subjecting a hydrocarbon feedstock plus added hydrogen to contact at hydrocracking conditions of temperature, pressure and space velocity with a catalyst comprising a Group VIII noble metal supported on a stabilized Y zeolite cracking base, said catalyst having been previously utilized for hydrocracking to a point of substantial deactivation, and having thereafter been reactivated by a process which comprises:
- (1) subjecting said deactivated catalyst to oxidative combustion to remove coke deposits therefrom;
- (2) contacting the decoked catalyst from step (1) with aqueous ammonia containing at least 0.1 wt.% NH.sub.3 for a sufficient time to effect a redispersal of said Group VIII noble metal;
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- (3) drying and calcining the ammoniated catalyst from step (2) in an oxidizing gas at a maximum temperature of about 600.degree.-850.degree. F, to effect deammoniation of said catalyst and to reduce its water content to between about 4% and 12% by weight, the temperature and water vapor partial pressures during said drying and calcining being controlled for the purpose of preventing reagglomeration of said Group VIII noble metal.
A hydrocracking process which comprises subjecting a hydrocarbon feedstock plus added hydrogen to contact with a catalyst comprising a Group VII noble metal supported on a stabilized Y zeolite cracking base, said contacting being carried out in the presence of less than about 200 ppmw of ammoniacal nitrogen, at a temperature between about 500.degree. and 650.degree. F and at a pressure and space velocity sufficient to give a substantial conversion of said feedstock to lower boiling hydrocarbons, said catalyst having been previously utilized for hydrocracking to a point of substantial deactivation, and having thereafter been reactivated by a process which comprises:
- (1) subjecting said deactivated catalyst to oxidative combustion to remove coke deposits therefrom;
- (2) contacting the decoked catalyst from step (1) with aqueous ammonia containing at least 0.1 wt.% NH.sub.3 for a sufficient time to effect a redispersal of said Group VIII noble metal;
- and
- (3) drying and calcining the ammoniated catalyst from step (2) in an oxidizing gas at a maximum temperature of about 600.degree.-850.degree. F, to effect deammoniation of said catalyst and to reduce its water content to between about 4% and 12% by weight, the temperature and water vapor partial pressures during said drying and calcining being controlled for the purpose of preventing reagglomeration of said Group VIII noble metal.
Dependencies are inferred from the claim text.