A co to co2 combustion promoter

Abstract

The invention is directed to a CO to CO2 combustion promoter comprising microsphere sized porous silica and/or alumina comprising particles further comprising on or more Group VIII noble metals wherein the noble metal is distributed in the particle as an eggshell such that a higher content of noble metal is present in the outer region of the particle as compared to the content of noble metal in the center of the particle.

1 . A CO to CO 2  combustion promoter comprising microsphere sized porous particles comprising at least one of silica and alumina and further comprising one or more Group VIII noble metals wherein the noble metal is distributed in the particle as an eggshell such that a higher content of noble metal is present in the outer region of the particle as compared to the content of noble metal in the centre of the particle. 
     
     
         2 . The combustion promoter according to  claim 1 , wherein the microsphere sized particles have an average (D50) size of between 60 and 90 microns as measured by laser diffraction. 
     
     
         3 . The combustion promoter according to  claim 1 , wherein microsphere sized particle is a gamma and/or theta alumina particle. 
     
     
         4 . The combustion promoter according to  claim 1 , wherein the microsphere sized particle is a spray dried silica particle. 
     
     
         5 . The combustion promoter according to  claim 1 , wherein the microsphere sized particle is an equilibrium or spent catalyst as obtained from a fluidized catalytic cracking (FCC) process. 
     
     
         6 . The combustion promoter according to  claim 1 , wherein the attrition index as measured according to ASTM D-5757 of the CO to CO 2  combustion promoter for a sieve fraction of combustion promoter particles of between 40 and 105 microns is between 5 and 25. 
     
     
         7 . The combustion promoter according to  claim 6 , wherein the attrition index of the CO to CO 2  combustion promoter for a sieve fraction of combustion promoter particles of between 40 and 105 microns is between 10 and 20. 
     
     
         8 . The combustion promoter according to  claim 1 , wherein the Group VIII noble metal is one or more of platinum, palladium, iridium, ruthenium and/or rhodium. 
     
     
         9 . The combustion promoter according to  claim 8 , wherein the Group VIII noble metal is platinum. 
     
     
         10 . The combustion promoter according to  claim 8 , wherein the Group VIII noble metal is palladium. 
     
     
         11 . The combustion promoter according to  claim 1 , wherein the particles further comprise at least one of cerium oxide and copper oxide. 
     
     
         12 . The combustion promoter according to  claim 11 , wherein the at least one of cerium oxide and copper oxide is distributed in the particle as an eggshell such that a higher content of the at least one of cerium oxide and copper oxide is present in the outer region of the particle as compared to the content of the at least one of cerium oxide and copper oxide in the centre of the particle. 
     
     
         13 . The combustion promoter according to  claim 1 , obtainable by a process comprising the following steps providing starting microsphere sized particles having pores, (a) introducing a medium in the pores of the starting microsphere sized particles to obtain filled porous particles and (b) contacting the filled particles with an aqueous salt solution of the Group VIII noble metal or metals wherein the Group VIII noble metal deposits predominantly in in the outer region of the particles thereby obtaining eggshell particles and optionally (c) at least one of dry and calcine the eggshell particles. 
     
     
         14 . The combustion promoter according to  claim 13 , wherein the starting microsphere sized particles are gamma alumina particles having an average (D50) size of between 60 and 90 microns, have a surface area (BET) of between 50 and 300 m 2 /g, and a pore volume of between 0.05 and 0.50 mL/g as measured as the water pore volume. 
     
     
         15 . The combustion promoter according to  claim 13 , wherein the medium in step (a) is water. 
     
     
         16 . The combustion promoter according to  claim 13 , wherein in step (b) the filled porous particles are contacted in step (b) with a volume of the aqueous salt solution of the Group VIII noble metal or metals which is less than the total volume of the pores of the starting microsphere sized particles. 
     
     
         17 . A process to prepare a CO to CO 2  combustion promoter comprising the following steps:
 (a) providing starting porous particles comprising at least one of silica and alumina and having pores and introducing a medium in the pores of starting porous particles to obtain filled porous particles,   (b) contacting the filled particles with an aqueous salt solution of a Group VIII noble metal or metals wherein the Group VIII noble metal deposits predominantly in in the outer region of the particles thereby obtaining intermediate eggshell particles and optionally   (c) at least one of dry and calcine the intermediate eggshell particles.   
     
     
         18 . The process according to  claim 17 , wherein the intermediate eggshell particles are dried in step (c). 
     
     
         19 . The process according to  claim 17 , wherein the starting porous particles are gamma alumina particles having an average (D50) size of between 60 and 90 μm, have a surface area (BET) of between 50-300 m 2 /g, and a pore volume of between 0.05 and 0.50 mL/g as measured as the water pore volume. 
     
     
         20 . The process according to  claim 17 , wherein the medium in step (a) is water. 
     
     
         21 . The process according to  claim 1 , wherein in step (b) the filled porous particles are contacted in step (b) with a volume of the aqueous salt solution of the Group VIII noble metal or metals which is less than the total volume of the pores of the starting particles. 
     
     
         22 . The process according to  claim 17 , wherein the Group VIII noble metal is at least one of platinum, palladium, iridium, ruthenium and rhodium. 
     
     
         23 . (canceled) 
     
     
         24 . Use of a combustion promoter according to  claim 1 , in a fluid catalytic cracking (FCC) unit. 
     
     
         25 . A fluid catalytic cracking (FCC) unit catalyst inventory comprising a combustion promoter according to  claim 1 . 
     
     
         26 .- 28 . (canceled) 
     
     
         29 . A FCC unit comprising a catalyst inventory comprising:
 a. a first FCC catalyst, and   b. a second FCC additive having a catalytic active component having a catalytic activity,   whereby the catalytic activity of the second FCC additive is negatively altered by the effects on the catalytically active component, whereby the second FCC additive is more sensitive to attrition and has a shorter residence time in the catalyst inventory as compared to the first FCC catalyst,   wherein the additive is a CO to CO 2  combustion promoter according to  claim 1 , and   wherein at least one of the catalytically active components of the additive comprises a metal and wherein the catalytic effect of the metal is negatively altered by sintering of the metal.   
     
     
         30 .- 33 . (canceled)