Reduced-emissions combustion utilizing multiple-component metallic combustion catalyst

Abstract

Diesel fuels containing low concentrations of specific bimetallic or trimetallic fuel-borne catalysts reduce particulates and other emissions without the use of after treatment devices, such as filters or catalysts, e.g., diesel particulate filters (DPF's) or diesel oxidation catalysts (DOC's) in the case of diesel engines. By utilizing a fuel containing a fuel-soluble catalyst comprised of platinum and at least one additional metal comprising cerium and/or iron, production of pollutants of the type generated by incomplete combustion is reduced. Preferred fuel borne catalyst levels will be low, e.g., from 0.05 to 0.5 ppm for platinum and 3 to 8 ppm for cerium and/or iron, thereby providing effective engine out emissions reductions without any aftertreatment device. Performance of lightly catalyzed aftertreatment devices will be improved with the subject invention.

1 . A diesel fuel for powering a diesel engine with reduced emission of particulates without the need for an after treatment device, comprising: 
 a base fuel comprising distillate,    and a fuel borne catalyst comprising platinum and cerium and/or iron, wherein the platinum is employed at a level of from 0.05 to 0.5 ppm and the levels of cerium and/or iron being from 0.5 to 10 ppm.    
     
     
         2 . A diesel fuel according to  claim 1 , wherein the diesel fuel contains less than 15 ppm sulfur.  
     
     
         3 . A diesel fuel according to  claim 1 , wherein the cerium and/or iron are present at total concentrations of from 3 to 8 ppm.  
     
     
         4 . A diesel fuel according to  claim 1 , which comprises a base fuel selected from the group consisting of ultra low sulfur diesel fuel, No. 1 diesel fuel, No. 2 diesel fuel, jet fuel, biologically-derived fuels, comprising fatty acid esters derived from triglycerides and mixtures of two or more of these.  
     
     
         5 . A method for reducing the emissions of particulates, hydrocarbons and carbon monoxide from a diesel engine directly out of the engine prior to contact with an oxidizer or particulate trap comprising: 
 adding a fuel-soluble platinum group metal composition and at least one other catalytic compound comprising fuel-soluble compounds of cerium to a diesel fuel to lower the emissions of particulates, unburned hydrocarbons and carbon monoxide, wherein the platinum is employed at a level of from 0.05 to 0.5 ppm and the levels of cerium and/or iron being from 3 to 10 ppm; and    operating a diesel engine with the fuel.    
     
     
         6 . The method according to  claim 5 , wherein the diesel fuel contains less than 15 ppm sulfur.  
     
     
         7 . The method according to  claim 5  wherein, wherein the cerium and/or iron are present at total concentrations of from 0.5 to less than 8 ppm.  
     
     
         8 . The method according to  claim 5 , wherein the diesel comprises a base fuel selected from the group consisting of ultra low sulfur diesel fuel, No. 1 diesel fuel, No. 2 diesel fuel, jet fuel, biologically-derived fuels, comprising fatty acid esters derived from triglycerides and mixtures of two or more of these.  
     
     
         9 . The method according to  claim 5 , wherein exhaust from operating the diesel engine is passed through a diesel particulate filter.  
     
     
         10 . The method according to  claim 5 , wherein exhaust from the diesel engine is passed through a diesel oxidation catalyst.  
     
     
         11 . A process for improving combustion of pilot fuel in a dual-fuel diesel engine, which operates principally on natural gas, comprising: adding to a pilot fuel, a multi catalyst composition comprising platinum at concentrations of from only 0.0005 to less than 0.15 ppm and cerium and/or iron at total concentrations of from only 0.5 to less than 8 ppm.  
     
     
         12 . A process for combusting a carbonaceous fuel comprising: mixing with fuel or combustion air a multi-component combustion catalyst comprising a platinum composition and cerium and/or iron compositions at levels reduced to as low as 0.0005 ppm for platinum and levels as low as 0.5 ppm for the cerium and iron; and combusting fuel with air in the presence of the catalyst in a regimen of treatment that will utilize effective catalyst levels for a time and under conditions, which will achieve one or more of the noted improvements.  
     
     
         13 . A process for combusting a carbonaceous fuel comprising: mixing with fuel or combustion air a multi-component combustion catalyst comprising a platinum composition and cerium and/or iron compositions at levels of from about 0.0005 to 2 ppm for platinum and levels of from about 1 to 25 ppm for the cerium and iron; combusting fuel with air in the presence of the catalyst in a regimen of treatment that will utilize effective catalyst levels for a time and under conditions, which will achieve one or more of the noted improvements; then, for at least a period of time changing the amount of catalyst utilized by mixing with fuel or combustion air a multi-component combustion catalyst comprising a platinum composition and cerium and/or iron compositions at levels reduced to as low as 0.0005 ppm for platinum and levels as low as 0.5 ppm for the cerium and iron; and combusting fuel with air in the presence of the catalyst in a regimen of treatment that will utilize effective catalyst levels for a time and under conditions, which will achieve one or more of the noted improvements.  
     
     
         14 . A process for combusting a carbonaceous fuel comprising: for at least a part of a treatment regimen utilizing higher catalyst concentrations, mixing with fuel a multi-component combustion catalyst comprising a platinum composition and cerium and/or iron compositions at levels of 0.0005 to less than 0.15 ppm for platinum and levels of 0.05 to less than 1.0 ppm for the cerium and iron; and combusting the fuel with air in a regimen of treatment that will achieve one or more of the noted improvements.