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

Abstract

Increased selectivity of middle distillate and increased catalyst activity are obtained in a hydrocracking process by the use of a catalyst containing 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, and a support.

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 consisting essentially of 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, and a support, wherein the Y zeolite has an overall silica to alumina mole ratio of from 5.0 to 11.0, wherein the catalyst contains from more than 2 wt-% to at most 5 wt-% beta zeolite based on the combined weight of the beta zeolite, the Y zeolite, and the support on a dried basis, and wherein the catalyst has a weight ratio of the Y zeolite to the beta zeolite of from 2.5 to 12.5 on a dried basis. 
   
   
       2 . The process of  claim 1  wherein the Y zeolite has a surface area of less than 800 m 2 /g. 
   
   
       3 . The process of  claim 1  wherein the Y zeolite 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 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 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 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 to the beta zeolite is from 2.5 to 3.0 on a dried basis. 
   
   
       9 . The process of  claim 1  wherein the catalyst contains from more than 2 wt-% to at most 3 wt-% beta zeolite based on the combined weight of the beta zeolite, the Y zeolite, and the support on a dried basis 
   
   
       10 . A composition of matter comprising a catalyst consisting of 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, and a support, wherein the Y zeolite has an overall silica to alumina mole ratio of from 5.0 to 11.0, wherein the catalyst contains from more than 2 wt-% to at most 5 wt-% beta zeolite based on the combined weight of the beta zeolite, the Y zeolite, and the support on a dried basis, and wherein the catalyst has a weight ratio of the Y zeolite to the beta zeolite of from 2.5 to 12.5 on a dried basis, wherein the Y zeolite has a surface area of less than 800 m 2 /g. 
   
   
       11 . The composition of  claim 10  wherein the hydrogenation component is selected from the group consisting of molybdenum, tungsten, nickel, cobalt, and the oxides and sulfides thereof. 
   
   
       12 . 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 feed stock, the catalyst consisting of one or more hydrogenation components in combination with a support consisting of 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 unit cell size of from 24.25 to 24.32 angstrom, wherein the Y zeolite 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, wherein the catalyst contains from more than 2 wt-% to at most 5 wt-% beta zeolite based on the combined weight of the beta zeolite, the Y zeolite, and the support on a dried basis, wherein the catalyst has a weight ratio of the Y zeolite to the beta zeolite of from 2.5 to 12.5 on a dried basis. 
   
   
       13 . The hydrocracking process of  claim 12  wherein at least 30 wt-% of the effluent boils below 371° C.