Catalytic processes and systems for base oil production from heavy feedstock

Abstract

A catalyst system is provided for dewaxing a heavy hydrocarbon feedstock to form a lubricant base oil. A layered catalyst system of the present invention may comprise a first hydroisomerization dewaxing catalyst disposed upstream from a second hydroisomerization dewaxing catalyst. Each of the first and second hydroisomerization dewaxing catalysts may be selective for the isomerization of n-paraffins. The first hydroisomerization catalyst has a first level of selectivity for the isomerization of n-paraffins, the second hydroisomerization dewaxing catalyst has a second level of selectivity for the isomerization of n-paraffins, and a layered catalyst system comprising the first and second hydroisomerization dewaxing catalysts has a third level of selectivity for the isomerization of n-paraffins. The third level of selectivity may be higher than each of the first level of selectivity and the second level of selectivity.

1 . A layered catalyst, comprising: 
       a first layer comprising a first hydroisomerization catalyst; and 
       a second layer comprising a second hydroisomerization catalyst, 
       wherein each of the first hydroisomerization catalyst and the second hydroisomerization catalyst comprises a 1-D, 10-ring molecular sieve and a Group VIII metal, wherein:
 the first hydroisomerization catalyst is disposed upstream from the second hydroisomerization catalyst, 
 the first hydroisomerization catalyst has a first level of selectivity for the isomerization of n-paraffins, 
 the second hydroisomerization catalyst has a second level of selectivity for the isomerization of n-paraffins, 
 the layered catalyst has a third level of selectivity for the isomerization of n-paraffins, and wherein the third level of selectivity is higher than each of the first level of selectivity and the second level of selectivity, and the first level of selectivity is at least substantially the same as the second level of selectivity. 
 
     
     
         2 . The layered catalyst according to  claim 1 , wherein:
 the first hydroisomerization catalyst has a higher concentration of the molecular sieve than the second hydroisomerization catalyst,   the first hydroisomerization catalyst has a higher concentration of the Group VIII metal than the second hydroisomerization catalyst,   each of the first hydroisomerization catalyst and the second hydroisomerization catalyst further comprises a metal modifier selected from the group consisting of Mg, Ca, Sr, Ba, K, La, Pr, Nd, Cr, and combinations thereof, and wherein the first hydroisomerization catalyst and the second hydroisomerization catalyst are disposed within a single reactor.   
     
     
         3 . The layered catalyst according to  claim 1 , wherein:
 the molecular sieve of each of the first hydroisomerization catalyst and the second hydroisomerization catalyst comprises zeolite SSZ-32,   the Group VIII metal of each of the first hydroisomerization catalyst and the second hydroisomerization catalyst comprises Pt, and wherein the ratio of the volume of the first hydroisomerization catalyst to the volume of the second hydroisomerization catalyst is in the range from about 3:2 to about 2:3.