Method to extend the utilization of a catalyst in a multistage reactor system

Abstract

The invention provides a method to extend the utilization of a catalyst in a multistage reaction system, provided that a primary reaction and a secondary (or more) catalyst-poisoning reaction occur on the same catalyst, and the rate of the secondary (or more), catalyst-poisoning reaction is faster than the rate of the primary reaction.

1 . A method for extending catalyst utilization comprising: 
 (a) passing a feedstock and hydrogen through at least two serially-connected reactors in positions R 1 , R 2 , . . . . R n , wherein n is the number of reactors, each reactor containing a catalyst, for a period until the catalyst in at least one most upstream reactor is deactivated for a secondary catalytic reaction or until the product from the most downstream reactor fails to meet a desired specification;    (b) bypassing the at least one most upstream reactor containing the deactivated catalyst of step (a) to pass the feedstock and hydrogen into at least one downstream reactor;    (c) reloading the at least one bypassed reactor of step (b) with fresh catalyst;    (d) placing the at least one reloaded reactor of step (c) downstream of at least one of the serially-connected reactors that were not reloaded with fresh catalyst in step (c); and    (e) repeating steps (a) through (d) to meet the product specification.    
   
   
       2 . The method of  claim 1 , wherein the catalyst is selected from the group consisting of a zero-valent element of one or more of the Group VIII elements of the Periodic Table.  
   
   
       3 . The method of  claim 2 , wherein the catalyst is selected from the group consisting of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, and Pt.  
   
   
       4 . The method of  claim 2 , wherein the catalyst is a porous metal structure.  
   
   
       5 . The method of  claim 4 , wherein the catalyst comprises Raney® nickel.  
   
   
       6 . The method of  claim 2 , wherein the catalyst is supported on a support.  
   
   
       7 . The method of  claim 6 , wherein the support is selected from the group consisting of carbon, alumina, silica, titania, silica-alumina, silica-titania, titania-alumina, clays, aluminosilicates, zeolites, water insoluble salts of calcium, water insoluble salts of barium, water insoluble salts of strontium, compounds thereof and combinations thereof.  
   
   
       8 . The method of  claim 7 , wherein the catalyst comprises nickel with heavy nickel loading supported on extrudates of silica/alumina.  
   
   
       9 . The method of  claim 1 , wherein the pressure is from about 100 kPa to about 20 MPa.  
   
   
       10 . The method of  claim 1 , wherein the hydrogen is fed to one or more of the reactors.  
   
   
       11 . The method of  claim 1 , wherein the temperature is from about minus 50° C. to about 400° C.  
   
   
       12 . The method of  claim 1 , further comprising adjusting the temperature to compensate for the number of serially-connected reactors in each of steps (b) and (d) for obtaining product with the desired specifications.  
   
   
       13 . The method of  claim 1 , wherein the feedstock is an organic liquid comprising a compound that can be hydrogenated by a catalyst of one or more of the Group VIII elements of the Periodic Table.  
   
   
       14 . The method of  claim 1 , wherein in step (d) the at least one reloaded reactor is placed downstream of the most downstream reactor that was not reloaded with the fresh catalyst in step (c).  
   
   
       15 . A method for extending catalyst utilization comprising: 
 (a) passing an organic feedstock and hydrogen through at least two serially-connected reactors in positions, R 1 , R 2 , . . . R n , wherein n is the number of reactors, each reactor containing a porous metal or supported catalyst, for a period until the catalyst in at least one most upstream reactor is deactivated for desulfurization or until the product from the most downstream reactor fails to meet a desired specification;    (b) bypassing the at least one most upstream deactivated reactor of step (a) to pass the feedstock and the hydrogen into downstream reactors;    (c) reloading the at least one bypassed reactor of step (b) with fresh catalyst;    (d) placing the at least one reloaded reactor of step (c) downstream; and    (e) repeating steps (a) through (d) to meet a desired specification.    
   
   
       16 . The method of  claim 15 , wherein the temperature is from about minus 50° C. to about 400° C.  
   
   
       17 . The method of  claim 15 , wherein the pressure is from about 100 kPa to about 20 MPa.  
   
   
       18 . The method of  claim 15 , further comprising adjusting the temperature to compensate for the number of serially-connected reactors in each of steps (b) and (d) to meet the desired product specifications.  
   
   
       19 . The method of  claim 15 , wherein the feedstock comprises 1,3-propanediol.  
   
   
       20 . The method of  claim 15 , wherein in step (d) the at least one reloaded reactor is placed last in the reactor series, in position Rn.  
   
   
       21 . The method of  claim 15 , wherein the catalyst comprises nickel with heavy nickel loading supported on extrudates of silica/alumina.  
   
   
       22 . A method for extending catalyst utilization comprising: 
 (a) passing a biochemically-derived organic feedstock containing 1,3-propanediol and hydrogen through at least two serially-connected reactors in positions R 1 , R 2 , . . . R n , wherein n is the number of reactors, each reactor containing a catalyst comprising nickel with heavy nickel loading supported on extrudates of silica/alumina, for a period until the catalyst in the most upstream reactor is deactivated for desulfurization or until the product from the most downstream reactor fails to meet a desired specification;    (b) bypassing the reactor in position R 1  to pass the feedstock and the hydrogen into the reactor in position R 2 ;    (c) reloading the bypassed reactor of step (b) with fresh catalyst;    (d) placing the reloaded reactor of step (c) in the reactor series downstream at position Rn; and    (e) repeating steps (a) through (d) to meet a desired specification.    
   
   
       23 . The method of  claim 22  further comprising adjusting the temperature to compensate for the number of serially-connected reactors in each of steps (b) and (d).  
   
   
       24 . The method of  claim 22 , wherein the temperature is from about minus 50° C. to about 200° C.  
   
   
       25 . The method of  claim 22 , wherein the temperature is from about 80° C. to about 140° C.