Dual catalyst system for hydroisomerization of Fischer-Tropsch wax and waxy raffinate

Abstract

The present invention relates to a process for converting Fischer-Tropsch wax to high quality lube basestocks using a molecular sieve Beta catalyst followed by a unidimensional intermediate pore molecular sieve with near circular pore structures having an average diameter of 0.50 nm to 0.65 nm wherein the difference between the maximum diameter and the minimum is ≦0.05 nm. Both catalysts comprise one or more Group VIII metals. For example, a cascaded two-bed catalyst system consisting of a first bed Pt/Beta catalyst followed by a second bed Pt/ZSM-48 catalyst is highly selective for wax isomerization and lube hydrodewaxing with minimal gas formation.

1 . An isoparaffinic basestock made by a process for converting a Fischer-Tropsch wax to an isoparaffinic lube basestock, comprising: 
 first, passing the Fischer-Tropsch wax and a hydrogen co-feed over a Beta catalyst comprising a Zeolite Beta and one or more Group VIII metals, to form an intermediate product; and    second, passing the intermediate product over a unidimensional molecular sieve catalyst comprising a unidimensional intermediate pore molecular sieve with near circular pore structures having an average diameter of 0.50 nm to 0.65 nm wherein the difference between a maximum diameter and a minimum diameter is ≦0.05 nm and one or more Group VIII metals;    wherein the isoparaffinic lube basestock has a viscosity index of at least 160 at a −20° C. lube pour point and a viscosity index of at least 135 at a pour point of no more than −50° C.    
   
   
       2 . The isoparaffinic lube basestock of  claim 1 , wherein the isoparaffinic lube basestock has less than 1 wt % aromatic content.  
   
   
       3 . A lubricant made by a process for converting a Fischer-Tropsch wax to an isoparaffinic lube basestock, comprising: 
 first, passing the Fischer-Tropsch wax and a hydrogen co-feed over a Beta catalyst comprising a Zeolite Beta and one or more Group VIII metals, to form an intermediate product; and    second, passing the intermediate product over a unidimensional molecular sieve catalyst comprising a unidimensional intermediate pore molecular sieve with near circular pore structures having an average diameter of 0.50 nm to 0.65 nm wherein the difference between a maximum diameter and a minimum diameter is ≦0.05 nm and one or more Group VIII metals;    wherein the lubricant has a viscosity index of at least 160 at a −20° C. lube pour point and a viscosity index of at least 135 at a pour point of no more than −50° C.    
   
   
       4 . A lubricant made by a process for converting a Fischer-Tropsch wax to an isoparaffinic lube basestock, comprising: 
 first, passing the Fischer-Tropsch wax and a hydrogen co-feed over the first bed of a cascaded two-bed catalyst system comprised of a Pt/Beta catalyst at a temperature of 500-600° F. (260 to 316° C.) and at a feed liquid hourly space velocity of 0.5 to 2 h −1  to form an intermediate product; and    second, passing the intermediate product over the second bed of a cascaded two-bed catalyst system comprised of a Pt/ZSM-48 catalyst at a temperature of 600-700° F. (316 to 371° C.) and at a feed liquid hourly space velocity of 0.5 to 2 h −1  to form a lubricant; and    wherein the process further comprises less than about 1,500 psig (102 atm) hydrogen, wherein the hydrogen is circulated at 1,000 to 6,000 scf/bbl (178 to 1068 n.L.L −1 ); and    wherein the Pt/Beta catalyst is comprised of a Zeolite Beta loaded with about 0.5 wt % to about 1 wt % of Pt based on the total weight of the Zeolite Beta, and the Zeolite Beta has an Alpha value less than about 15 prior to loading of the Pt; and the ZSM-48 catalyst is loaded with about 0.5 wt % to about 1 wt % of Pt based on the total weight of the ZSM-48; and    wherein the lubricant has a viscosity index of at least 160 at a −20° C. lube pour point and a viscosity index of at least 135 at a pour point of no more than −50° C.