US2003129124A1PendingUtilityA1

A BARIUM SUBSTITUTED-SULFUR TOLERANT LEAN NOx TRAP

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Assignee: FORD GLOBAL TECH INCPriority: Oct 18, 2001Filed: Feb 6, 2003Published: Jul 10, 2003
Est. expiryOct 18, 2021(expired)· nominal 20-yr term from priority
Inventors:Diane GuttridgeJun LiRonald G. HurleyRobert J. KudlaWilliam L. H. Watkins
Y10S502/524B01D 2257/404B01D 2257/302B01J 23/002B01D 2255/91B01J 2523/00B01D 2255/2065B01D 2255/2047B01D 53/9422B01D 2255/40B01D 2255/20715B01J 21/005
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Claims

Abstract

Abstract of Disclosure The present invention provides a composition and method for storing and reducing NOx from lean burn internal combustion engines. The present invention uses composite metal oxides, in spinel structure, in conjunction with the typical lean NOx trap formulation to form an integrated lean NOx trap. The composite metal oxides in spinel structure act primarily as a SOx trapping element and also secondarily as a NOx trapping element within the integrated LNT. In this integrated LNT, the sulfur is trapped and released in a way that does not allow the sulfur to go to the primary NOx trapping element an alkali or earth metal - and thus prevents the integrated lean NOx trap from becoming poisoned, thereby leaving more reactive sites for NOx trapping and conversion.

Claims

exact text as granted — not AI-modified
Claims 
     
         1.   A sulfur-tolerant lean NOx trap, comprising: 
       a lean NOx trap doped with a composite metal oxide having a formula of Mg x Ba y Al 2 O 4 , wherein x is a number in the range of 0.1-0.7 and y is a number in the range of 0.3-0.9. 
     
     
         2.   The lean NOx trap of  claim 1 , wherein the composite metal oxide is spinel in structure. 
     
     
         3.   The lean NOx trap of  claim 1 , wherein the composite metal oxide comprises Mg x Ba y Al 2 O· 4 BaO, wherein x is a number in the range of 0.1-0.7 and y is a number in the range of 0.3-0.9. 
     
     
         4.   The lean NOx trap of  claim 1 , wherein the composite metal oxide comprises Mg x Ba y Al 2 O· 4 CeO 2 ,wherein x is a number in the range of 0.1-0.7 and y is a number in the range of 0.3-0.9. 
     
     
         5.   The lean NOx trap of  claim 4 , wherein the trap is doped with said composite metal oxide to provide a composition comprising between 0.1  20 wt% of the lean NOx trap. 
     
     
         6.   The lean NOx trap of  claim 4 , wherein the trap is doped with said composite metal oxide to provide a composition comprising between 2-15 wt% of the lean NOx trap. 
     
     
         7.   The lean NOx trap of  claim 1 , wherein the composite metal oxide comprises Mg x Ba y Al 2 O· 4 zCeO 2 -ZrO 2 , wherein x is a number in the range of 0.1-0.7, y is a number in the range of 0.3-0.9, and z is a number in the range of 1-20 wt%. 
     
     
         8.   The lean NOx trap of  claim 7 , wherein z is a number in the range of 2-15 wt%. 
     
     
         9.   The lean NOx trap of  claim 1 , wherein the trap is doped with said composite metal oxide to provide a composition comprising between 2-30 wt% of the lean NOx trap. 
     
     
         10.   The lean NOx trap of  claim 1 , wherein the trap is doped with said composite metal oxide to provide a composition comprising between 2-20 wt% of the lean NOx trap. 
     
     
         11.   The lean NOx trap of  claim 1 , wherein the trap is doped with said composite metal oxide to provide a composition comprising between 4-10 wt% of the lean NOx trap. 
     
     
         12.   The lean NOx trap of  claim 1 , wherein the trap is doped with said metal oxide after preparation of the lean NOx trap. 
     
     
         13.   The lean NOx trap of  claim 1 , wherein the trap is doped with said metal oxide during preparation of the lean NOx trap. 
     
     
         14.   A method for removing NOx and SOx from an exhaust gas stream, comprising: 
       placing a lean NOx trap in the exhaust gas stream, wherein the lean NOx trap is doped with a composite metal oxide having a formula of Mg x Ba y Al 2 O 4 , wherein x is a number in the range of 0.1-0.7 and y is a number in the range of 0.3-0.9. 
     
     
         15.   The method of  claim 14 , wherein the composite metal oxide is added in the ratio of 2 to 30. 
     
     
         16.   The method of  claim 14 , wherein the composite metal oxide is added in the ratio of 2 to 20. 
     
     
         17.   The method of  claim 14 , wherein the composite metal oxide is added in the ratio of 4 to 10. 
     
     
         18.   The method of  claim 14 , wherein the composite metal oxide is spinel in structure. 
     
     
         19.   The method of  claim 14 , wherein the metal oxide is Mg 0.1-0.7 Ba 0.3-0.9 Al 2 O 4 . 
     
     
         20.   The method of  claim 14 , wherein the composite metal oxide is Mg 0.1-0.7 Ba 0.3-0.9 Al 2 O· 4 BaO. 
     
     
         21.   The method of  claim 14 , wherein the composite metal oxide is Mg 0.1-0.7 Ba 0.3-0.9 Al 2 O· 4 CeO 2 . 
     
     
         22.   The method of  claim 14 , wherein the composite metal oxide is Mg 0.1-0.7 Ba 0.3-0.9 Al 2 O· 4 zCeO 2 -ZrO 2 . 
     
     
         23.   A sulfur trap for the removal of sulfur in an exhaust stream, comprising: 
       an alumina substrate and a composite metal oxide having a formula of Mg x Ba y Al 2 0 4 , wherein x is a number in the range of 0.1-0.7 and y is a number in the range of 0.3-0.9. 
     
     
         24.   The sulfur trap of  claim 23 , wherein the composite metal oxide is spinel in structure. 
     
     
         25.   The sulfur trap of  claim 23 , wherein the sulfur trap is positioned upstream from any lean NOx trap in the exhaust system.

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