Zeolite membranes for selective oxidation of carbon monoxide in mixed hydrogen gas source

Abstract

Methods and apparatus are taught for selectively oxidizing carbon monoxide in a source of gas containing carbon monoxide and hydrogen. A gas containing carbon monoxide and hydrogen is fed into a membrane reactor ( 10, 50, 60 ) capable of selectively absorbing the carbon monoxide. Preferably, the reactor comprises a substantially defect-free zeolite membrane ( 4 ) having at one metal that acts as an oxidation catalyst. The zeolite membrane ( 4 ) may be supported on a porous ceramic support ( 2, 52, 61 ) and the average pore diameter is preferably between about 0.3 nm and about 1.0 nm. Moreover, the substantially defect-free zeolite membrane ( 4 ) preferably has a thickness between about 0.1 micron and about 50.0 microns. The at least one metal is preferably capable of selectively oxidizing the carbon monoxide and is preferably platinum. Preferably, the temperature of reactor housing is maintained at about 200-300 degrees centigrade.

1 . An apparatus ( 10 ,  50 ,  60 ) for selectively oxidizing a target oxidizable substance in the presence of another oxidizable material, comprising: 
 an enclosure ( 12 ,  50 ,  60 ), such as a reactor housing, having a gas feed inlet ( 13   a ,  54 ,  64 ) and a gas discharge port ( 13   c ,  55 ,  65 ) and    a substantially defect-free zeolite membrane ( 4 ) disposed between and separating the gas feed inlet ( 13   a ,  54 ,  64 ) from the gas discharge port ( 13   c ,  55 ,  65 ), the zeolite membrane ( 4 ) having gas-permeable fine pores and having a retention time for a polar gas, such as carbon monoxide, that is longer than a non-polar gas, such as hydrogen, the zeolite membrane ( 4 ) comprising at least one metal that acts as an oxidation catalyst, wherein a mixture of an oxidizable material, such as hydrogen, and a target oxidizable substance, such as carbon monoxide, is supplied to the gas feed inlet ( 13   a ) and forced to permeate through the substantially defect-free zeolite membrane ( 4 ) and the target oxidizable substance, such as carbon monoxide, is selectively oxidized without significant oxidation of the other oxidizable material, such as hydrogen.    
     
     
         2 . An apparatus according to  claim 1 , wherein the zeolite membrane ( 4 ) is mechanically supported by an inorganic porous support ( 2 ,  52 ,  61 ).  
     
     
         3  An apparatus according to claims  1  or  2 , wherein the gas-permeable fine pores of the zeolite membrane ( 4 ) have an average diameter between about 0.3 nm and about 1.0 nm.  
     
     
         4 . An apparatus according to claims  1 ,  2  or  3 , wherein the substantially defect-free zeolite membrane ( 4 ) has a thickness of between about 0.1 micron and about 50.0 microns.  
     
     
         5 . An apparatus according to claims  1 ,  2 ,  3  or  4 , wherein the zeolite membrane ( 4 ) comprises a Y-type zeolite.  
     
     
         6 . A method of making a zeolite membrane comprising: 
 contacting a porous ceramic support surface ( 2 ,  52 ,  61 ) with zeolite particles;    disposing the porous ceramic support surface in a solution of zeolite starting materials,    heating and pressurizing the porous ceramic support surface ( 2 ,  52 ,  61 ) and the zeolite starting materials, thereby forming a zeolite membrane ( 4 ) on the porous ceramic support ( 2 ,  52 ,  61 ); and    introducing at least one metal into the zeolite membrane ( 4 ), wherein the at least one metal is capable of oxidizing target molecules.    
     
     
         7 . A method according to  claim 6 , wherein the zeolite particles comprise a X-type zeolite.  
     
     
         8 . A method of selectively oxidizing a target oxidizable material, such as carbon monoxide, in a source of gas containing the target oxidizable material and another oxidizable material, such as hydrogen, comprising: 
 forcing the gas containing the target oxidizable material, such as carbon monoxide, and the other oxidizable material, such as hydrogen, through a substantially defect-free zeolite membrane ( 4 ) capable of selectively retaining the target oxidizable material, the substantially defect-free zeolite membrane ( 4 ) comprising at one metal that acts as an oxidation catalyst, the at least one metal selectively oxidizing the target oxidizable material.    
     
     
         9 . A method according to  claim 8 , wherein the gas is fed through the zeolite membrane ( 4 ) at a temperature of about 200-300° C.  
     
     
         10 . A method according to claims  8  or  9 , wherein the gas-permeable fine pores of the zeolite membrane ( 4 ) have an average diameter between about 0.3 nm and about 1.0 nm.  
     
     
         11 . A method according to claim,  8 ,  9  or  10 , wherein substantially defect-free zeolite membrane ( 4 ) has a thickness of between about 0.1 micron and about 50.0 microns.  
     
     
         12 . A method according to any of claims  8 - 11 , wherein the zeolite membrane ( 4 ) comprises a Y-type zeolite.  
     
     
         13 . A method according to any of claims  8 - 12 , wherein the at least one metal is platinum.  
     
     
         14 . A method according to any of claims  8 - 13 , wherein the substantially defect-free zeolite membrane ( 4 ) is supported on a porous support ( 2 ,  52 ,  61 ).  
     
     
         15 . A method according to  claim 14 , wherein the porous support ( 2 ,  52 ,  61 ) is a porous ceramic support, such as alumina.