Cold flow improver compositions for fuels

Abstract

The present invention is a composition comprising a three additive system for improving the cold flow properties of distillate fuel oils using certain copolymers or homopolymers in combination with at least two conventional cold flow additives, an additive concentrate, and a method for improving the low temperature properties of a fuel oil.

1 . A fuel oil composition comprising: 
 (a) a fuel oil,    (b) a polymeric substance selected from the group consisting of: 
 1) copolymers of one or more monoesters of maleic acid, itaconic acid or citraconic acid with one or more branched monohydric alcohols having 1 to 18 carbon atoms and more than a single methyl branch, or one or more straight-chain monohydric alcohols having less than 10 carbon atoms; and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms;  
 2) copolymers of a C 4  to C 6  dicarboxylic acid anhydride and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms, esterified with one or more monohydric alcohols having 1 to 18 carbon atoms;  
 3) copolymers of one or more alkylacrylates or alkylmethacrylates, where the alkyl groups have 1 to 18 carbon atoms, and acrylic or methacrylic acid;  
 4) copolymers of one or more acrylic acids or methacrylic acids and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms;  
 5) homopolymers of one or more monoesters of an unsaturated C 4  to C 6  dicarboxylic acid with a branched monohydric alcohol having 1 to 18 carbon atoms and more than a single methyl branch, or a straight-chain monohydric alcohol having less than 10 carbon atoms, and  
 6) homopolymers of an C 4  to C 6  dicarboxylic acid anhydride, followed by esterification with one or more monohydric alcohols having 1 to 18 carbon atoms, and  
   (c) two or more cold flow additives selected from the group consisting of 
 1) ethylene-unsaturated monomer copolymers;  
 2) comb polymers;  
 3) polar nitrogen compounds;  
 4) polyoxyalkylene compounds, and  
 5) di-block hydrocarbon polymers.  
   
     
     
         2 . The composition of  claim 1 , in which the branched alcohol has 6 to 14 carbon atoms.  
     
     
         3 . The composition of  claim 1 , in which the vinyl ester is vinyl 2-ethylhexanoate.  
     
     
         4 . The composition of  claim 1 , in which the polymeric substance has an Mn of 1,000 to 20,000.  
     
     
         5 . The composition of  claim 1 , in which the alcohol is 2-ethylhexyl alcohol or isodecyl alcohol.  
     
     
         6 . The composition of  claim 1 , in which the polymeric substance is post-reacted with one or more amines.  
     
     
         7 . The composition of  claim 1 , in which the two or more cold flow additives are an ethylene-unsaturated monomer copolymer and a polar nitrogen compound.  
     
     
         8 . The composition of  claim 1 , in which the polymeric substance is present in an amount of from 0.1 to 1,000 ppm by weight.  
     
     
         9 . The composition of  claim 1 , in which the fuel oil is a petroleum based middle distillate boiling in the range of 110 to 500° C.  
     
     
         10 . An additive concentrate comprising a solvent miscible with fuel oil and an additive system comprising: 
 (a) a polymeric substance selected from the group consisting of: 
 1) copolymers of one or more monoesters of maleic acid, itaconic acid or citraconic acid with one or more branched monohydric alcohols having 1 to 18 carbon atoms and more than a single methyl branch, or one or more straight-chain monohydric alcohols having less than 10 carbon atoms; and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms;  
 2) copolymers of a C 4  to C 6  dicarboxylic acid anhydride and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms, esterified with one or more monohydric alcohols having 1 to 18 carbon atoms;  
 3) copolymers of one or more alkylacrylates or alkylmethacrylates, where the alkyl groups have 1 to 18 carbon atoms, and acrylic or methacrylic acid;  
 4) copolymers of one or more acrylic acids or methacrylic acids and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms;  
 5) homopolymers of one or more monoesters of an unsaturated C 4  to C 6  dicarboxylic acid with a branched monohydric alcohol having 1 to 18 carbon atoms and more than a single methyl branch, or a straight-chain monohydric alcohol having less than 10 carbon atoms, and  
 6) homopolymers of an C 4  to C 6  dicarboxylic acid anhydride, followed by esterification with one or more monohydric alcohols having 1 to 18 carbon atoms, and  
   (b) two or more cold flow additives selected from the group consisting of 
 1) ethylene-unsaturated monomer copolymers;  
 2) comb polymers;  
 3) polar nitrogen compounds;  
 4) polyoxyalkylene compounds, and  
 5) di-block hydrocarbon polymers.  
   
     
     
         11 . A method for improving the low temperature properties of a fuel oil, which comprises: 
 blending a fuel oil with    a) a polymeric group consisting of: 
 1) copolymers of one or more monoesters of maleic acid, itaconic acid or citraconic acid with one or more branched monohydric alcohols having 1 to 18 carbon atoms and more than a single methyl branch, or one or more straight-chain monohydric alcohols having less than 10 carbon atoms; and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms;  
 2) copolymers of a C 4  to C 6  dicarboxylic acid anhydride and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms, esterified with one or more monohydric alcohols having 1 to 18 carbon atoms;  
 3) copolymers of one or more alkylacrylates or alkylmethacrylates, where the alkyl groups have 1 to 18 carbon atoms, and acrylic or methacrylic acid;  
 4) copolymers of one or more acrylic acids or methacrylic acids and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms;  
 5) homopolymers of one or more monoesters of an unsaturated C 4  to C 6  dicarboxylic acid with a branched monohydric alcohol having 1 to 18 carbon atoms and more than a single methyl branch, or a straight-chain monohydric alcohol having less than 10 carbon atoms, and  
 6) homopolymers of an C 4  to C 6  dicarboxylic acid anhydride, followed by esterification with one or more monohydric alcohols having 1 to 18 carbon atoms, and  
   (b) two or more cold flow additive selected from the group consisting of: 
 1) copolymers of one or more monoesters of maleic acid, itaconic acid or citraconic acid with one or more branched monohydric alcohols having 1 to 18 carbon atoms and more than a single methyl branch, or one or more straight-chain monohydric alcohols having less than 10 carbon atoms; and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms;  
 2) copolymers of a C 4  to C 6  dicarboxylic acid anhydride and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms, esterified with one or more monohydric alcohols having 1 to 18 carbon atoms;  
 3) copolymers of one or more alkylacrylates or alkylmethacrylates, where the alkyl groups have 1 to 18 carbon atoms, and acrylic or methacrylic acid;  
 4) copolymers of one or more acrylic acids or methacrylic acids and one or more vinyl esters of carboxylic acids having 2 to 18 carbon atoms;  
 5) homopolymers of one or more monoesters of an unsaturated C 4  to C 6  dicarboxylic acid with a branched monohydric alcohol having 1 to 18 carbon atoms and more than a single methyl branch, or a straight-chain monohydric alcohol having less than 10 carbon atoms, and  
 6) homopolymers of an C 4  to C 6  dicarboxylic acid anhydride, followed by esterification with one or more monohydric alcohols having 1 to 18 carbon atoms.