Additives for Reduction of Exhaust Emissions From Compression Ignition Engines

Abstract

Exhaust emissions resulting from the combustion of hydrocarbon fuels in compression ignition engines may be reduced using a homopolymer that may be polyisobutylene, polypropylene, and/or hyperbranched polyalpha-olefins. Optionally, an alkyl nitrate such as 2-ethylhexylnitrate (2EHN), and/or a peroxide, such as hydrogen peroxide, may also be used together with the homopolymer. Both NOx and particulate matter emissions (PM) may be reduced using ppm quantities of the additive compositions; alternatively, NOx emissions may be lowered or reduced while PM emissions do not substantially increase.

1 . A method for reducing emissions of a distillate fuel comprising adding to the distillate fuel an effective amount of an additive composition for reducing the emissions of the distillate fuel, the additive composition comprising a homopolymer selected from the group consisting of polyisobutylene, polypropylene, hyperbranched polymers, and mixtures thereof. 
   
   
       2 . The method of  claim 1 , where the additive composition further comprises a component selected from the group consisting of an alkyl nitrate, a peroxide and combinations thereof. 
   
   
       3 . The method of  claim 2  where the effective amount of the component ranges from about 100 to about 3000 ppm and the effective amount of the homopolymer ranges from about 20 to about 2500 ppm, both based on the total distillate fuel. 
   
   
       4 . The method of  claim 1  where the fuel has reduced NOx and/or particulate matter emissions as compared to an otherwise identical fuel absent the additive composition. 
   
   
       5 . The method of  claim 1  where the fuel has reduced NOx and particulate matter emissions are substantially the same as or lower compared to an otherwise identical fuel absent the additive composition. 
   
   
       6 . A method for reducing emissions of a distillate fuel comprising adding to the distillate fuel an additive composition comprising:
 from about 20 to about 2500 ppm, based on the total distillate fuel, of a homopolymer selected from the group consisting of polyisobutylene, polypropylene, hyperbranched polyalpha-olefins, and mixtures thereof; and   from about 100 to about 3000 ppm, based on the total distillate fuel, of a component selected from the group consisting of an alkyl nitrate, a peroxide and combinations thereof.   
   
   
       7 . The method of  claim 6  where the fuel has reduced NOx and/or particulate matter emissions as compared to an otherwise identical fuel absent the additive composition. 
   
   
       8 . The method of  claim 6  where the fuel has reduced NOx and particulate matter emissions are substantially the same as or lower compared to an otherwise identical fuel absent the additive composition. 
   
   
       9 . An additive composition for reducing the emissions of distillate fuels comprising:
 a homopolymer selected from the group consisting of polyisobutylene, polypropylene, hyperbranched polymers, and mixtures thereof; and   a component selected from the group consisting of an alkyl nitrate, a peroxide, and combinations thereof.   
   
   
       10 . The composition of  claim 9  where the volume ratio of homopolymer to the component ranges from about 1:1 to about 1:100. 
   
   
       11 . The composition of  claim 9  where the component is an alkyl nitrate selected from the group consisting of 2-ethylhexyl nitrate (2EHN), iso-propyl nitrate, iso-amylnitrate, iso-hexylnitrate, cyclohexyl nitrate, dodecyl nitrate, diglycol nitrate and tetraglycol nitrate. 
   
   
       12 . A distillate fuel comprising:
 a hydrocarbon selected from the group consisting of diesel fuel, gasoline, jet fuel, and kerosene; and   an effective amount of an additive composition for reducing the emissions of the distillate fuel comprising a homopolymer selected from the group consisting of polyisobutylene, polypropylene, hyperbranched polymers, and mixtures thereof.   
   
   
       13 . The distillate of  claim 12  where the additive composition further comprises a component selected from the group consisting of an alkyl nitrate, a peroxide, and combinations thereof. 
   
   
       14 . The distillate fuel of  claim 13  where the effective amount of the component ranges from about 100 to about 3000 ppm and the effective amount of the homopolymer ranges from about 20 to about 2500 ppm, both based on the total distillate fuel. 
   
   
       15 . The distillate fuel of  claim 12  where the fuel has reduced NOx and/or particulate matter emissions as compared to an otherwise identical fuel absent the additive composition. 
   
   
       16 . The distillate fuel of  claim 12  where the fuel has reduced NOx and particulate matter emissions are substantially the same or lower as compared to an otherwise identical fuel absent the additive composition. 
   
   
       17 . The distillate fuel of  claim 13  where the component is an alkyl nitrate selected from the group consisting of 2-ethylhexyl nitrate (2EHN), iso-propyl nitrate, iso-amylnitrate, iso-hexylnitrate, cyclohexyl nitrate, dodecyl nitrate, diglycol nitrate and tetraglycol nitrate. 
   
   
       18 . A distillate fuel comprising:
 a hydrocarbon selected from the group consisting of diesel fuel, gasoline, jet fuel and kerosene; and   an effective amount of an additive composition for reducing the emissions of the distillate fuel comprising
 a homopolymer selected from the group consisting of polyisobutylene, polypropylene, hyperbranched polymers, and mixtures thereof; and 
 a component selected from the group consisting of an alkyl nitrate, a peroxide, and combinations thereof; 
   
     where the fuel has reduced NOx and/or particulate matter emissions as compared to an otherwise identical fuel absent the additive composition. 
   
   
       19 . The distillate fuel of  claim 18  where the effective amount of the component ranges from about 100 to about 3000 ppm and the effective amount of the homopolymer ranges from about 20 to about 2500 ppm, both based on the total distillate fuel. 
   
   
       20 . The distillate fuel of  claim 18  where the component is an alkyl nitrate selected from the group consisting of 2-ethylhexyl nitrate (2EHN), iso-propyl nitrate, iso-amylnitrate, iso-hexylnitrate, cyclohexyl nitrate, dodecyl nitrate, diglycol nitrate and tetraglycol nitrate.