Patent ID: 8475648
Filing Date: 2013-07-02
Classification: B01J,C10G

Abstract:
1. A process for catalytically dewaxing a waxy hydrocarbon feedstock, comprising: a) contacting the hydrocarbon feedstock in a first hydroisomerization zone under first hydroisomerization dewaxing conditions with a first hydroisomerization catalyst to provide a first isomerization stream; and b) contacting at least a portion of the first isomerization stream in a second hydroisomerization zone under second hydroisomerization dewaxing conditions with a second hydroisomerization catalyst to provide a second isomerization stream; wherein the first and second hydroisomerization catalysts comprise a layered catalyst system, 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 system has a third level 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; wherein each of the first hydroisomerization catalyst and the second hydroisomerization catalyst comprises a molecular sieve and a Group VIII metal, each of the first hydroisomerization catalyst and the second hydroisomerization catalyst is selective for isomerization of n-paraffins in the feedstock; wherein the first hydroisomerization zone and the second hydroisomerization zone are disposed within the same reactor; and wherein each of the first hydroisomerization catalyst and the second hydroisomerization catalyst is doped with a metal modifier selected from the group consisting of Mg, Ca, Sr, Ba, K, La, Pr, Nd, Cr, and combinations thereof.