Hydrocracking Catalyst Containing Beta and Y Zeolites, and Process for its use to make Distillate

Abstract

Increased selectivity of middle distillate and/or increased catalyst activity are obtained in a hydrocracking process by the use of a catalyst containing a beta zeolite and a Y zeolite having a unit cell size of from 24.25 to 24.32 angstrom. The catalyst may also contain an additional Y zeolite having a unit cell size of from 24.33 to 24.38 angstrom.

1 . A process for hydrocracking a hydrocarbon feedstock which comprises contacting the feedstock at a temperature from about 232° C. to about 454° C. and at a pressure from about 5171 kPa(g) to about 24132 kpa(g) in the presence of hydrogen with a catalyst comprising a hydrogenation component, a beta zeolite having an overall silica to alumina mole ratio of less than 30 and a SF 6  adsorption capacity of at least 28 wt-%, a Y zeolite having a unit cell size of from 24.25 to 24.32 angstrom (Y Zeolite I), and a support, wherein the Y Zeolite I has an overall silica to alumina mole ratio of from 5.0 to 11.0, wherein the catalyst contains from 0.1 to 2 wt-% beta zeolite based on the combined weight of the beta zeolite, the Y Zeolite I, and the support on a dried basis, and wherein the catalyst has a weight ratio of the Y Zeolite I to the beta zeolite of from 1 to 10 on a dried basis. 
   
   
       2 . The process of  claim 1  wherein the Y Zeolite I has a surface area of less than 800 m 2 /g. 
   
   
       3 . The process of  claim 1  wherein the Y Zeolite I is prepared by a process comprising the steps of:
 a) partially ammonium exchanging a sodium Y zeolite;   b) calcining the zeolite resulting from step (a) in the presence of water vapor;   c)ammonium exchanging the zeolite resulting from step (b); and   d) calcining the zeolite resulting from step (c) in the presence of water vapor.   
   
   
       4 . The process of  claim 1  wherein the Y Zeolite I is prepared by a process comprising the steps of:
 a) partially ammonium exchanging a sodium Y zeolite;   b) calcining the zeolite resulting from step (a) in the presence of water vapor;   c) contacting the zeolite resulting from step (b) with a fluorosilicate salt in the form of an aqueous solution; and   d) calcining the zeolite resulting from step (c) in the presence of water vapor.   
   
   
       5 . The process of  claim 1  wherein the Y Zeolite I is prepared by a process comprising the steps of:
 a) contacting a sodium Y zeolite with a fluorosilicate salt in the form of an aqueous solution; and   b) calcining the zeolite resulting from step (a) in the presence of water vapor.   
   
   
       6 . The process of  claim 1  wherein the hydrogenation component is selected from the group consisting of molybdenum, tungsten, nickel, cobalt, and the oxides and sulfides thereof. 
   
   
       7 . The process of  claim 1  wherein the Y Zeolite I has a unit cell size of from 24.26 to 24.30 angstrom. 
   
   
       8 . The process of  claim 1  wherein the weight ratio of the Y Zeolite I to the beta zeolite is from 2.3 to 5.9 on a dried basis. 
   
   
       9 . The process of  claim 1  wherein the unit cell size of the Y Zeolite I is a first unit cell size, and the catalyst comprises an additional Y zeolite (Y Zeolite II) having a second unit cell size at least 0.04 angstrom greater than the first unit cell size. 
   
   
       10 . The process of  claim 9  wherein the second unit cell size is from 24.33 to 24.38 angstrom. 
   
   
       11 . The process of  claim 9  wherein the catalyst has a weight ratio of the Y Zeolite I to the Y Zeolite II of from 1.5 to 6.5 on a dried basis. 
   
   
       12 . The process of  claim 9  wherein the catalyst contains a positive amount of at most 5 wt-% of the Y Zeolite I and the Y Zeolite II based on the combined weight of the beta zeolite, the Y Zeolite I, the Y Zeolite II, and the support on a dried basis. 
   
   
       13 . The process of  claim 9  wherein the Y Zeolite II is prepared by a process comprising the steps of:
 a) partially ammonium exchanging a sodium Y zeolite;   b) calcining the zeolite resulting from step (a) in the presence of water vapor;   c)ammonium exchanging the zeolite resulting from step (b); and   d) calcining the zeolite resulting from step (c) in the presence of water vapor.   
   
   
       14 . The process of  claim 9  wherein the Y Zeolite II is prepared by a process comprising the steps of:
 a) partially ammonium exchanging a sodium Y zeolite;   b) calcining the zeolite resulting from step (a) in the presence of water vapor;   c) contacting the zeolite resulting from step (b) with a fluorosilicate salt in the form of an aqueous solution; and   d) calcining the zeolite resulting from step (c) in the presence of water vapor.   
   
   
       15 . The process of  claim 9  wherein the Y Zeolite II is prepared by a process comprising the steps of:
 a) contacting a sodium Y zeolite with a fluorosilicate salt in the form of an aqueous solution; and   b) calcining the zeolite resulting from step (a) in the presence of water vapor.   
   
   
       16 . A composition of matter comprising a catalyst comprising a hydrogenation component, a beta zeolite having an overall silica to alumina mole ratio of less than 30 and a SF 6  adsorption capacity of at least 28 wt-%, a Y zeolite having a unit cell size from 24.25 to 24.32 angstrom (Y Zeolite I), and a support, wherein the Y Zeolite I has an overall silica to alumina mole ratio of from 5.0 to 11.0, wherein the catalyst contains from 0.1 to 2 wt-% beta zeolite based on the combined weight of the beta zeolite, the Y Zeolite I, and the support on a dried basis, and wherein the catalyst has a weight ratio of the Y Zeolite I to the beta zeolite of from 1 to 10 on a dried basis, wherein the Y Zeolite I has a surface area of less than 800 m 2 /g. 
   
   
       17 . The composition of  claim 16  wherein the hydrogenation component is selected from the group consisting of molybdenum, tungsten, nickel, cobalt, and the oxides and sulfides thereof. 
   
   
       18 . The composition of  claim 16  wherein the unit cell size of the Y Zeolite I is a first unit cell size, and the catalyst comprises an additional Y zeolite (Y Zeolite II) having a second unit cell size of from 24.33 to 24.38 angstrom and at least 0.04 angstrom greater than the first unit cell size. 
   
   
       19 . A hydrocracking process comprising contacting a hydrocarbon feedstock with a catalyst at a temperature between about 232° C. and about 454° C. and at a pressure between about 5171 kpa(g) and about 24132 kPa(g) in the presence of hydrogen so as to produce an effluent of lower average boiling point than the hydrocarbon feedstock, the catalyst comprising one or more hydrogenation components in combination with a support comprising an inorganic refractory oxide, zeolite beta in a form catalytically active for cracking hydrocarbons, a Y zeolite catalytically active for cracking hydrocarbons and having a first unit cell size of from 24.25 to 24.32 angstrom (Y Zeolite I), wherein the Y Zeolite I has an overall silica to alumina mole ratio of from 5.0 to 11.0 and a surface area of less than 800 m 2 /g, and an additional Y zeolite (Y Zeolite II) having a second unit cell size of from 24.33 to 24.38 angstrom, wherein the second unit cell size is at least 0.04 angstrom greater than the first unit cell size, wherein the catalyst contains from 0.1 to 2 wt-% beta zeolite based on the combined weight of the beta zeolite, the Y Zeolite I, the Y Zeolite II, and the support on a dried basis, wherein the catalyst has a weight ratio of the Y Zeolite I to the beta zeolite of from 1 to 10 on a dried basis, and wherein the catalyst has a weight ratio of the Y Zeolite I to the Y Zeolite II of from 1.5 to 6.5 on a dried basis. 
   
   
       20 . The hydrocracking process of  claim 19  wherein at least 30 wt-% of the effluent boils below 371° C.