Abstract The response of a middle distillate petroleum fuel oil to the addition of a flow improver, such as a copolymer of ethylene, whereby flow and pumpability at low temperatures are improved, is increased by incorporating said fuel oil a small proportion of a paraffinic wax in sufficient quantity to furnish from about 0.03 to about 2 weight percent of normal paraffin hydrocarbons whose average molecular weight is within the range of from 300 to 650. The paraffinic wax that is added has a molar heat of fusion that is greater than the molar heat of fusion of the first wax that separates from the fuel upon cooling to or below its cloud point. Preferably, the added wax contains normal paraffin hydrocarbons ranging from n-C24 to at least n-C28 inclusive.
Improved petroleum distillate fuel as defined by claim 1 wherein said copolymer is a copolymer of ethylene and an unsaturated ester.
Claim 2
Dependent Claim
20 words
Improved petroleum distillate fuel as defined by claim 1 wherein said copolymer is a copolymer of ethylene and another olefin.
Claim 3
Dependent Claim
20 words
Improved petroleum distillate fuel as defined by claim 1 wherein said copolymer is a copolymer of ethylene and vinyl acetate.
Claim 4
Dependent Claim
26 words
Improved petroleum distillate fuel as defined by claim 1 wherein said copolymer is a terpolymer of ethylene, vinyl acetate, and aliphatic alcohol diester of fumaric acid.
Claim 5
Dependent Claim
25 words
Improved petroleum distillate fuel as defined by claim 1 wherein said added wax includes normal paraffin hydrocarbons in the range of C24 to C28 inclusive.
Claim 6
Dependent Claim
45 words
Improved petroleum distillate fuel as defined by claim 1 wherein said added wax has a molar heat of fusion that is from 3, 000 to 11,000 calories per mole greater than the molar heat of fusion of said first wax that separates from said fuel.