Hydrocracking process utilizing rejuvenated catalyst

Claim 2

A PROCESS FOR THE HYDROCRACKING OF A HYDROCARBON FEEDSTOCK TO PRODUCE LOWER BOILING HYDROCARBONS, WHICH COMPRISES SUBJECTING SAID FEEDSTOCK IN ADMIXTURE WITH ADDED HYDROEN TO HYDROCRACKING CONDITIONS OF PRESSURE AND TEMPERATURE IN CONTACT WITH A CATALYST COMPRISING A NON-ZEOLITE GROUP VIII NOBLE METAL SUPPORTED ON A SILICEOUS ZEOLITE MONO-AND/OR ALSO, AS ORIGINALLY PREPARED, CONTAINED ZEOLITE MONO- AND/OR DIVALENT METAL CATIONS, SAID CATALYST HAVING BEEN PREVIOUSLY SUBJECTED TO THERMAL AND/OR HYDROTHERMAL CONDITIONS RESULTING IN A MALDISTRIBUTION OF SSAID GROUP VIIINOBLE METAL ON SAID CARRIER WITH RESULTANT REDUCTION IN HYDROGENATION ACTIVITY AND IN A DELETERIOUS MIGRATION OF SAID ZEOLITE METAL CATIONS RESULTING IN A REDUCTION IN CRACKING ACTIVITY, AND WHICH HAS THEREAFTER BEEN REJUVENATED TO GREATER THAN IT ORIGINAL FRESH ACTIVITY BY A PROCESS WHICH COMPRISES: A. DIGESTING SAID CATALYST IN AN OXIDIZED OR SULFIED STATE WITH A REAGENT CONSISTING ESSENTIALLY OF A 0.1 - 30 WEIGHT PERCENT AQUEOUS AMMONIA SOLUTION CONTAINING A DISSOLVED AMMONIUM SALT, AND CORRELATING THE CONTACTING TIME WITH THE TEMPERATURE AND REAGENT STRENGTH SO AS TO EXTRACT FROM SAID CATALYST AT LAST A SUBSTANTIAL PORTION OF SAID ZEOLITE METAL CATIONS WHILE RETAINING IN THE CATALYST AT LEAST ABOUT 70 PERCENT OF SAID GROUP VIII NOBLE METAL. B. SEPARATING SAID CATALYST FROM THE RESULTING AMMONIACAL EXTRACT OF ZEOLITE METAL CATIONS; AND C. DRYING AND CALCINING THE SEPARATED CATALYST.

Claim 3

A process as defined in claim 1 wherein said zeolitic metals comprise an alkali metal.

Claim 4

calcining the partially dried and deammoniated catalyst in a stream of oxygen-containing gas at temperatures controlled between about 500* and 1,200*F. to maintain the dewpoint of the effluent gas stream below about 40*F., at least the terminal portion of said calcining being carried out at temperatures between about 750* and 1,200*F.

Claim 5

calcining the partially dried and deammoniated catalyst in a stream of oxygen-containing gas at temperatures controlled between about 500* and 1,200*F. to maintain the dewpoint of the effluent gas stream below about 40*F., at least the terminal portion of said calcining being carried out at temperatures between about 750* and 1,200*F.

Claim 6

A process as defined in claim 1 wherein said drying and calcining in step (C) are performed by:

Claim 7

A process as defined in claim 1 wherein said Group VIII noble metal is palladium.

Claim 8

A process as defined in claim 1 wherein said siliceous zeolite carrier is a crystalline molecular sieve.

Claim 9

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, as originally prepared, contained zeolitic hydrogen ions and sodium cations, said catalyst having previously been utilized in a hydrocarbon conversion process to substantial deactivation and subsequently regenerated by oxidative combustion, and during said hydrocarbon conversion and/or regeneration having been subjected to thermal and/or hydrothermal conditions resulting in a reduction in hydrogenation activity and cracking activity, said catalyst having thereafter been rejuvenated to greater than its original fresh activity by a process which comprises: A. digesting said catalyst in an oxidized or sulfided state with at least about 2 volumes per volume of catalyst of a reagent consisting essentially of a 0.1 - 30 weight-percent aqueous ammonia solution containing a dissolved ammonium salt, and correlating the contacting time with the temperature and reagent strength so as to extract from said catalyst at least a substantial portion of said zeolitic sodium cations while retaining in the catalyst at least about 70 percent of said Group VIII noble metal; B. separating said catalyst from the resulting ammoniacal extract of zeolitic sodium cations; and C. drying and calcining the separated catalyst.

Claim 10

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, as originally prepared, contained zeolitic hydrogen ions and sodium cations, said catalyst having previously been utilized in a hydrocarbon conversion process to substantial deactivation and subsequently regenerated by oxidative combustion, and during said hydrocarbon conversion and/or regeneration having been subjected to thermal and/or hydrothermal conditions resulting in a reduction in hydrogenation activity and cracking activity, said catalyst having thereafter been rejuvenated to greater than its original fresh activity by a process which comprises: A. digesting said catalyst in an oxidized or sulfided state with at least about 2 volumes per volume of catalyst of a reagent consisting essentially of a 0.1 - 30 weight-percent aqueous ammonia solution containing a dissolved ammonium salt, and correlating the contacting time with the temperature and reagent strength so as to extract from said catalyst at least a substantial portion of said zeolitic sodium cations while retaining in the catalyst at least about 70 percent of said Group VIII noble metal; B. separating said catalyst from the resulting ammoniacal extract of zeolitic sodium cations; and C. drying and calcining the separated catalyst.

Claim 11

A process as defined in claim 6 wherein said Group VIII noble metal is palladium.

Claim 12

A process as defined in claim 6 wherein the contacting conditions in step (A) are controlled so as to extract at least about 20 percent of said zeolitic sodium ions.

Claim 13

A process as defined in claim 6 wherein said contacting in step (A) is carried out at a temperature between about 10* and 125*C.