Reformate stream cooler with a catalytic coating for use in a gas generation system

Abstract

A gas generation system comprises a reformer ( 1 ) to generate a hydrogen-containing reformate stream ( 4 ), a reformate stream cooler ( 2 ), and a shift stage ( 3 ) down-stream of the reformate stream cooler to purify the reformate stream. The surfaces of the cooler that come into contact with the reformate stream are coated with a material that contains at least one catalytically active constituent. The coating is selected such that it also protects against corrosion and sooting in the presence of oxidizing, reducing, and carbon-containing gases. By directly utilizing the coated reformate stream cooler as a catalytically active reactor unit, a water-gas shift reaction to reduce the carbon monoxide concentration takes place to some extent in the cooler prior to the reformate stream entering the actual shift stage. This enables the size of subsequent shift stage(s) to be reduced.

1 . A gas generation system comprising: 
 a reformer to generate a reformate stream,    a cooler downstream of the reformer to cool the reformate stream, and    a shift stage downstream of the cooler to reduce the carbon monoxide concentration in the reformate stream,    wherein surfaces of the cooler that come into contact with the reformate stream are coated with a cooler coating that is soot-inhibiting and is catalytically active with respect to the water-gas shift reaction.    
     
     
         2 . The system of  claim 1 , wherein the composition of the cooler coating varies along the reformate stream flow path.  
     
     
         3 . The system of  claim 2 , wherein the cooler coating comprises at least two areas of different composition, which differ with respect to soot-inhibiting activity, or catalytic activity with respect to the water-gas shift reaction, or both.  
     
     
         4 . The system of any one of  claims 1  to  3 , wherein the system further comprises a cooler feed line connecting the reformer to the cooler and a cooler discharge line connecting the cooler to the shift stage, and wherein the cooler feed line and the cooler discharge line are coated with a line coating that is soot-inhibiting material and is catalytically active with respect to the water-gas shift reaction.  
     
     
         5 . The system of  claim 4  wherein the line coating exhibits greater soot-inhibiting activity and lesser activity with respect to the water-gas shift reaction than the cooler coating.  
     
     
         6 . The system of  claim 4  wherein the cooler coating comprises a first material of the same composition as the line coating, and a second material that exhibits greater catalytic activity with respect to the water-gas shift reaction and a lower soot-inhibiting activity than the material.  
     
     
         7 . The system of  claim 1 , wherein the surfaces of the cooler that come into contact with the reformate stream are coated with at least one layer of a base material, wherein the base material is disposed between the surfaces and the cooler coating, and wherein the base material comprises a metal-containing substance, selected from the group consisting of chromium, silicon, aluminum, magnesium, manganese, titanium, rare earths, compounds of chromium, silicon, aluminum, magnesium, manganese, titanium and rare earths, and alloys of chromium, silicon, aluminum, magnesium, manganese, titanium and rare earths.