Ultra-low sulfur fuel compositions containing organometallic additives

Abstract

A method, apparatus, and fuel composition for the protection of a catalytic after treatment system and a method for protecting a catalytic after treatment system in a low sulfur fuel system are discloseD. A scavenging agent is introduced into the base fuel in an amount effective to complex with catalytic poisoning combustion by products and reduce catalyst poisoning. In a preferred embodiment, the scavenger is an organometallic compound which also imparts additional desirable properties to the fuel.

Having described the invention as above, we claim:  
     
         1 . A method of enhancing performance durability of a catalytic emissions control system in a fuel combustion system containing a catalytic device having a transition metal, alkali or alkaline earth metal element, or combinations thereof (catalytic elements), said combustion system producing at least one byproduct, comprising: 
 supplying a fuel containing 100 ppm or less sulfur to said fuel combustion system,    said combustion system being provided with a scavenger, said scavenger complexing with at least one combustion byproduct,    said scavenger being supplied in an effective amount to complex with the at least one fuel combustion byproduct,    whereby the impact of said fuel combustion byproduct on said emissions control system are reduced.    
     
     
         2 . The method of  claim 1 , wherein said fuel contains 50 ppm or less sulfur.  
     
     
         3 . The method of  claim 2 , wherein said fuel contains 30 ppm or less sulfur.  
     
     
         4 . The method of  claim 3 , wherein said fuel contains 20 ppm or less sulfur.  
     
     
         5 . The method of  claim 4 , wherein said fuel contains 15 ppm or less sulfur.  
     
     
         6 . The method of  claim 1 , wherein said fuel comprises a spark-ignition fuel.  
     
     
         7 . The method of  claim 1 , wherein said fuel comprises a compression-ignition fuel.  
     
     
         8 . A method as claimed in  claim 1 , wherein the scavenger is an organometallic compound.  
     
     
         9 . A method as claimed in  claim 8 , wherein the scavenger includes at least one metal selected from the group consisting of magnesium, manganese, barium, cerium, strontium, iron, calcium, platinum, palladium and mixtures thereof.  
     
     
         10 . A method as claimed in  claim 8 , wherein the scavenger comprises at least one alkali and/or alkaline earth metal.  
     
     
         11 . A method as claimed in  claim 8 , wherein the scavenger comprises at least one transition metal.  
     
     
         12 . A method as claimed in  claim 11 , wherein said organometallic compound at least one manganese tricarbonyl compound.  
     
     
         13 . A method as claimed in  claim 1 , wherein the scavenger is present in an amount so as to provide from 0.5 to about 120 mg of metal per liter of fuel.  
     
     
         14 . A method as claimed in  claim 13 , wherein the scavenger is present in an amount so as to provide from about 1 to about 66 mg of metal per liter of fuel.  
     
     
         15 . A method as claimed in  claim 1 , wherein the combustion system operates at a lambda>1.2.  
     
     
         16 . A method as claimed in  claim 1 , wherein the emissions reduction system comprises a catalytic convertor.  
     
     
         17 . A method as claimed in  claim 1 , wherein the emissions reduction system comprises a lean NO x  trap.  
     
     
         18 . A method as claimed in  claim 1 , wherein the catalytic device comprises barium.  
     
     
         19 . An apparatus for reducing emissions control system poisoning in a lean fuel combustion system having a stream of effluent, comprising: 
 a combustion system which operates at a lambda>1,    a base fuel containing 100 ppm or less sulfur, and    present, in an effective amount to complex with at least one combustion byproduct in the effluent stream, a scavenger.    
     
     
         20 . The apparatus of  claim 19 , wherein the base fuel contains 50 ppm or less sulfur.  
     
     
         21 . An apparatus as claimed in  claim 19 , wherein the scavenger comprises at least one organometallic compound.  
     
     
         22 . An apparatus as claimed in  claim 21 , wherein the organometallic compound comprises at least one manganese tricarbonyl compound.  
     
     
         23 . An apparatus as claimed in  claim 19 , wherein the scavenger comprises at least one element selected from the group consisting of transition metal elements.  
     
     
         24 . An apparatus as claimed in  claim 19 , wherein the scavenger comprises at least one metal selected from the group consisting of magnesium, manganese, barium, cerium, strontium, iron, calcium, platinum, palladium and mixtures thereof.  
     
     
         25 . An apparatus as claimed in  claim 19 , wherein the fuel comprises a compression-ignition fuel and the emissions control system comprises at least one member selected from the group consisting of an oxidation catalyst, a three-way catalyst, a catalyzed particulate trap, exhaust gas sensors and a lean NO x  trap.  
     
     
         26 . An apparatus as claimed in  claim 19 , wherein the fuel comprises a spark-ignition fuel and the emissions control system comprises at least one member selected from the group consisting of an oxidation catalyst, a three-way catalyst, exhaust gas sensors and a lean NO x  trap.  
     
     
         27 . A catalytic emissions control system for the after treatment of a combustion process exhaust stream, comprising: 
 an exhaust passageway for the passage of an exhaust stream containing exhaust byproducts from the combustion of a fuel,    at least one catalytic material having catalytic activity, said catalytic material being located within the exhaust passageway and contacting the exhaust stream,    wherein the exhaust stream contains a scavenger which complexes with at least one of the exhaust byproducts and reduces the impact of the byproduct upon the catalytic material, and    wherein said fuel contains 100 ppm or less sulfur.    
     
     
         28 . An emissions system as claimed in  claim 27 , wherein the scavenger comprises an organometallic compound.  
     
     
         29 . An emissions system as claimed in  claim 27 , wherein the scavenger comprises at least one manganese tricarbonyl compound.  
     
     
         30 . An emissions system as claimed in  claim 27 , wherein the combustion exhaust byproducts comprises sulfur.