Combination of zeolite and alumina impregnated with a noble metal(s) for COS and THT removal at low temperatures (<40 degree C) in fuel cell processor applications

Abstract

The present invention is a process for removing sulfur-containing compounds from gaseous fuels and hydrocarbons, such as natural gas, at temperatures of less than about 100° C. The sulfur-contaminated feedstream is placed in intimate contact with a catalyst-sorbent which comprises a noble metal, a zeolite, and an alumina in a single reactor bed.

1 . A process for removing sulfur compounds from a gaseous hydrocarbon feedstream comprising contacting said mixture with a catalyst-sorbent comprising at least one noble metal, at least one zeolite, and at least one oxide support, wherein said catalyst-sorbent is packed into a reactor bed and said reactor bed is maintained at a temperature of from about 0° C. to about 100° C.  
   
   
       2 . The process of  claim 1  wherein said noble metal is selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, alloys thereof, mixed metal compounds thereof, and combinations thereof.  
   
   
       3 . The process of  claim 2  wherein said noble metal comprises both palladium and platinum in a ratio Pd:Pt of between about 1:1 and about 6:1.  
   
   
       4 . The process of  claim 1  wherein said noble metal comprises from about 0.1 wt % to about 5 wt % defined in terms of total catalyst-sorbent weight.  
   
   
       5 . The process of  claim 4  wherein said noble metal comprises from about 0.5 wt % to about 2 wt % defined in terms of total catalyst-sorbent weight.  
   
   
       6 . The process of  claim 1  wherein said zeolite comprises zeolite X, zeolite Y, zeolite beta, a zeolite having a BEA structure, a zeolite having a MOR structure, or a combination thereof.  
   
   
       7 . The process of  claim 1  wherein said zeolite comprises from about 50 wt % to about 90 wt % defined in terms of total catalyst-sorbent weight.  
   
   
       8 . The process of  claim 1  wherein said oxide support is selected from alumina, silica, titania, zirconia, and combinations thereof.  
   
   
       9 . The process of  claim 8  wherein said oxide support comprises alumina.  
   
   
       10 . The process of  claim 1  wherein said oxide support comprises from about 10 wt % to about 50 wt % defined in terms of total catalyst-sorbent weight.  
   
   
       11 . The process of  claim 1  wherein said catalyst-sorbent has a pore volume of at least about 0.3 cm 3 /g.  
   
   
       12 . The process of  claim 1  wherein said catalyst-sorbent has a specific surface area of at least 300 m 2 /g.  
   
   
       13 . The process of  claim 1  wherein said reactor bed temperature is less than about 60° C.  
   
   
       14 . The process of  claim 1  where the gas hourly space velocity is less than about 3000 h −1 .  
   
   
       15 . The process of  claim 1  wherein said gaseous hydrocarbon feedstream comprises natural gas, methane, propane, or liquefied petroleum gas, and said feedstream comprises at least one sulfur compound selected from the group consisting of carbonyl sulfide, thiols, disulfides, saturated heterocyclic sulfur compounds, tetrahydrothiophene and combinations thereof.  
   
   
       16 . A process for removing sulfur compounds selected from the group consisting of carbonyl sulfide, thiols, disulfides, saturated heterocyclic sulfur compounds, tetrahydrothiophene and combinations thereof, from a gaseous feedstream comprising hydrocarbons selected from natural gas, methane, propane, liquefied petroleum gas, and combinations thereof, wherein said process comprises contacting said feedstream with a catalyst-sorbent comprising at least one noble metal selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, alloys thereof, mixed metal compounds thereof, and combinations thereof, and at least one zeolite, and at least one oxide support, wherein said catalyst-sorbent is packed into a reactor bed and said reactor bed is maintained at a temperature of from about 0° C. to about 100° C.  
   
   
       17 . The process of  claim 16  wherein said noble metal comprises from about 0.1 wt % to about 5 wt % defined in terms of total catalyst-sorbent weight, and said zeolite comprises from about 50 wt % to about 90 wt % defined in terms of total catalyst-sorbent weight, and said oxide support comprises from about 10 wt % to about 50 wt % defined in terms of total catalyst-sorbent weight.  
   
   
       18 . The process of  claim 16  wherein said noble metal comprises both palladium and platinum in a ratio Pd:Pt of between about 1:1 and about 6:1.  
   
   
       19 . The process of  claim 16  where the gas hourly space velocity is less than about 3000 h −1 .  
   
   
       20 . A process for removing sulfur compounds selected from the group consisting of carbonyl sulfide, thiols, disulfides, saturated heterocyclic sulfur compounds, tetrahydrothiophene and combinations thereof, from a gaseous feedstream comprising hydrocarbons selected from natural gas, methane, propane, liquefied petroleum gas, and combinations thereof, wherein said process comprises contacting said feedstream with a catalyst-sorbent comprising from about 0.1 wt % to about 5 wt % of at least one noble metal, and from about 50 wt % to about 90 wt % of at least one zeolite, and from about 10 wt % to about 50 wt % of at least one oxide support, wherein said catalyst-sorbent is packed into a reactor bed and said reactor bed is maintained at a temperature of from about 0° C. to about 100° C.