Lubricity improver compositions and methods for improving lubricity of hydrocarbon fuels

Abstract

Fuel additive compositions for enhancing the lubricity of hydrocarbon fuels in which the natural lubricity has been diminished due to treatment of the fuel to reduce sulfur and aromatic components for improved emissions are disclosed. Preferably, the fuel additive compositions include (1) a polyalkenylsuccinimide having a high molecular weight; (2) a low aromatic paraffinic base oil; and (3) a low aromatic petroleum distillate to impart improved lubricity to hydrocarbon fuels.

1 . A lubricity enhancing fuel additive comprising a polyalkenylsuccinimide having a molecular weight greater 2,000 daltons, wherein the lubricity enhancing fuel additive increases the lubricity of a hydrocarbon fuel by at least 10 percent using the High Frequency Rotating Rig test described in ASTM D 6079. 
     
     
         2 . The lubricity enhancing fuel additive of  claim 1 , wherein the polyalkenylsuccinimide comprises a mono-polyalkenylsuccinimide. 
     
     
         3 . The lubricity enhancing fuel additive of  claim 1 , wherein the polyalkenylsuccinimide comprises a di-polyalkenylsuccinimide. 
     
     
         4 . The lubricity enhancing fuel additive of  claim 1 , wherein the polyalkenylsuccinimide comprises a mono-polyalkenylsuccinimide and a di-polyalkenylsuccinimide. 
     
     
         5 . The lubricity enhancing fuel additive of  claim 4 , wherein the mono-polyalkenylsuccinimide and the di-polyalkenylsuccinimide are present in a ratio of 3 to 1. 
     
     
         6 . The lubricity enhancing fuel additive of  claim 4 , wherein the mono-polyalkenylsuccinimide and the di-polyalkenylsuccinimide are present in a ratio of 1 to 3. 
     
     
         7 . The lubricity enhancing fuel additive of  claim 4 , wherein the mono-polyalkenylsuccinimide and the di-polyalkenylsuccinimide are present in a ratio of 1 to 1. 
     
     
         8 . The lubricity enhancing fuel additive of  claim 1 , further comprising a low aromatic paraffinic base oil. 
     
     
         9 . The lubricity enhancing fuel additive of  claim 8 , wherein the weight proportion of the low aromatic paraffinic base oil is in the range from 50 to 90 weight percent of the lubricity enhancing fuel additive. 
     
     
         10 . The lubricity enhancing fuel additive of  claim 8 , wherein the weight proportion of the low aromatic paraffinic base oil is in the range from 60 to 80 weight percent of the lubricity enhancing fuel additive. 
     
     
         11 . The lubricity enhancing fuel additive of  claim 8 , further comprising a low aromatic petroleum distillate. 
     
     
         12 . The lubricity enhancing fuel additive of  claim 11 , wherein the weight proportion of the low aromatic petroleum distillate is in the range from 5 to 50 weight percent of the lubricity enhancing fuel additive. 
     
     
         13 . The lubricity enhancing fuel additive of  claim 11 , wherein the weight proportion of the low aromatic petroleum distillate is in the range from 15 to 40 weight percent of the lubricity enhancing fuel additive. 
     
     
         14 . The lubricity enhancing fuel additive of  claim 11 , wherein the weight proportion of the low aromatic petroleum distillate is in the range from 20 to 25 weight percent of the lubricity enhancing fuel additive. 
     
     
         15 . A process for forming an lubricity enhancing fuel additive, the process comprising the steps of:
 forming a first polyalkenylsuccinimide having a molecular weight greater than 2,000 daltons;   combining at room temperature the first polyalkenylsuccinimide with a low aromatic paraffinic base oil and a low aromatic petroleum distillate to form the lubricity enhancing fuel additive, wherein the low aromatic paraffinic base oil is present in the lubricity enhancing fuel additive in a range from 50 to 90 weight percent and the low aromatic petroleum distillate is present in the lubricity enhancing fuel additive in a range from 5 to 50 weight percent,   wherein the lubricity of the fuel is increased at least 10 percent using the High Frequency Rotating Rig test described in ASTM D 6079.   
     
     
         16 . The process of  claim 15 , wherein a second polyalkenylsuccinimide is combined with the first polyalkenylsuccinimide, the low aromatic paraffinic base oil, and the low aromatic petroleum distillate to form the lubricity enhancing fuel additive. 
     
     
         17 . The process of  claim 16 , wherein the first polyalkenylsuccinimide and the second polyalkenylsuccinimide are combined in a ratio of 3 to 1. 
     
     
         18 . The lubricity enhancing fuel additive of  claim 16 , wherein the first polyalkenylsuccinimide and the second polyalkenylsuccinimide are combined in a ratio of 1 to 3. 
     
     
         19 . The lubricity enhancing fuel additive of  claim 16 , wherein the first polyalkenylsuccinimide and the second polyalkenylsuccinimide are combined in a ratio of 1 to 1. 
     
     
         20 . The lubricity enhancing fuel additive of  claim 16 , wherein the first polyalkenylsuccinimide comprises a mono-polyalkenylsuccinimide and the second polyalkenylsuccinimide comprises a di-polyalkenylsuccinimide.