US 3,943,051 AGranted

Hydrocarbon conversion processes utilizing rejuvenated zeolite catalysts

AssigneeUnion Oil Company of California

InventorJohn W. Ward

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Abstract

Siliceous zeolite catalysts comprising zeolitic mono- and/or divalent metal cations and a non-zeolitic Group VIII noble metal hydrogenating component supported thereon, which catalysts have undergone damage by thermal and/or hydrothermal stresses resulting in a maldistribution of the metal components, are rejuvenated in activity by a first treatment with a volumetric excess of aqueous ammonium hydroxide, followed by a second treatment with an extractive proportion of an aqueous ammonium salt solution. The combined treatments have a twofold effect of bringing about a desirable redistribution of the Group VIII noble metal, and of exchanging out at least a portion of undesired zeolitic mono- and/or divalent metal ions. A highly advantageous procedure for carrying out the rejuvenation involves simply neutralizing the ammonium hydroxide-catalyst mixture from the first treatment with a suitable acid to give the ammonium salt desired for the second treatment. Hydrocarbon conversion processes utilizing the rejuvenated catalysts are also disclosed.

Claims14

Dependent claims

A hydrocarbon conversion process which comprises subjecting a hydrocarbon feedstock plus added hydrogen to contact at elevated conversion temperatures with a catalyst comprising a non-zeolitic Group VIII noble metal supported on a siliceous zeolite carrier which also contains zeolitic mono- and/or divalent metal ions, said catalyst having been previously subjected to thermal and/or hydrothermal conditions resulting in a maldistribution of said Group VIII noble metal on said carrier with resultant reduction in hydrogenation activity and/or in a deleterious migration of said zeolitic metal cations resulting in a reduction in cracking activity, and which has thereafter been rejuvenated to substantially its original fresh activity by a process which comprises:

A. contacting said catalyst in an oxidized or sulfided state with a volumetric excess of a reagent consisting essentially of a 0.1 - 30 weight-percent aqueous ammonium hydroxide solution, and correlating the contacting time with the temperature and reagent strength so as to effect a substantial improvement in hydrogenation activity of said catalyst while retaining therein at least about 90 percent of said Group VIII noble metal;
B. subjecting the treated catalyst from step (A) to contact with an extractive proportion of an aqueous ammonium salt solution at a pH below about 8 to exchange out a substantial portion of said zeolitic metal cations:
C. separating the catalyst from the resulting ammonium salt extract of zeolitic metal cations;
and
D. drying and calcining the separated catalyst.

2 more elements

A process for the hydrocracking of a hydrocarbon feedstock to produce lower boiling hydrocarbons, which comprises subjecting said feedstock in admixture with added hydrogen to hydrocracking conditions of pressure and temperature in contact with a catalyst comprising a non-zeolitic Group VIII noble metal supported on a Y zeolite base which also contains zeolitic hydrogen ions and sodium ions, said catalyst having previously been utilized in a hydrocracking process to substantial deactivation and subsequently regenerated by oxidative combustion, and during said previous hydrocracking and/or regeneration having been subjected to thermal and/or hydrothermal conditions resulting in a reduction in hydrogenation activity and/or cracking activity, said catalyst having thereafter been rejuvenated to an activity level greater than that resulting from said oxidative combustion, by a rejuvenation process comprising the steps of:

A. contacting said regenerated catalyst in its oxidized state with a volumetric excess of a reagent consisting essentially of a 0.1 - 30 weight-percent aqueous ammonium hydroxide solution, and correlating the contacting time with the temperature and reagent strength so as to effect a substantial improvement in hydrogenation activity of said catalyst while retaining therein at least about 90 percent of said Group VIII noble metal;
B. subjecting the treated catalyst from step (A) to contact with an extractive proportion of an aqueous ammonium salt solution at a pH below about 8 to exchange out a substantial portion of said zeolitic metal cations;
C. separating the catalyst from the resulting ammonium salt extract of zeolitic sodium cations;
and
D. drying and calcining the separated catalyst.

2 more elements

Dependencies are inferred from the claim text.