A method for preparing a refinery fuel composition having a target octane number, comprises: (i) blending fuel components in proportions which are designed to give a refinery fuel composition with an octane number which is greater than the target octane number by a margin of less than 1; and (ii) testing the octane number of the refinery fuel composition and, if the octane number falls below the target octane number, blending the refinery fuel composition with a non-metallic octane-boosting additive. A further method comprises: (a) passing a first refinery fuel composition comprising a non-metallic octane-boosting additive to a fuel handing system, and discharging the first refinery fuel composition from the fuel handing system; and (b) passing a second refinery fuel composition to the fuel handing system.

Lubricity additives for hydrocarbon fuels are provided according to formula I:

##STR00001##

wherein n is 1 or 0; each Q is independently selected from oxygen and sulfur; each R is independently selected from C8-C60 alkenyl groups which are substituted or unsubstituted; and L is a linking group comprising 0-20 carbons which may be substituted or unsubstituted and may optionally comprise catenary heteroatoms. Fuel mixtures comprising a hydrocarbon fuel; and a lubricity additive according to the present disclosure are also provided. Methods of making lubricity additives comprise reacting an alkenyl succinic anhydrides (ASA's) with certain bisamides or bisthioamides.

Lubricity additives for hydrocarbon fuels are provided according to formula I:

##STR00001##

wherein n is 1 or 0; each Q is independently selected from oxygen and sulfur; each R is independently selected from C8-C60 alkenyl groups which are substituted or unsubstituted; and L is a linking group comprising 0-20 carbons which may be substituted or unsubstituted and may optionally comprise catenary heteroatoms. Fuel mixtures comprising a hydrocarbon fuel; and a lubricity additive according to the present disclosure are also provided. Methods of making lubricity additives comprise reacting an alkenyl succinic anhydrides (ASA's) with certain bisamides or bisthioamides.

A method for reducing the tendency of a hydrocarbon fluid to oxidise comprises combining an additive having a chemical structure comprising a 6-membered aromatic ring sharing two adjacent aromatic carbon atoms with a 6- or 7-membered saturated heterocyclic ring, the 6- or 7-membered saturated heterocyclic ring comprising a nitrogen atom directly bonded to one of the shared carbon atoms to form a secondary amine and an atom selected from oxygen or nitrogen directly bonded to the other shared carbon atom, the remaining atoms in the 6- or 7-membered heterocyclic ring being carbon with the hydrocarbon fluid. The additive may also be used for protecting a system in which a hydrocarbon fluid is used from the effects of oxidation.

The present disclosure provides methods for identifying a hydrocarbon fuel, such as the presence and/or amounts of marker compounds having a fluorescence intensity and, through correlation, the presence and/or amounts of additive package(s) within the hydrocarbon fuel.

The present disclosure relates to a method of reducing regeneration frequency of a diesel particulate filter in a vehicle combusting diesel fuel. The method includes combusting a diesel fuel in a vehicle engine having a diesel particulate filter and wherein the diesel particulate filter requires regeneration thereof. The diesel fuel has less than about 50 ppmw of sulfur and one or more select additives to reduce a measured frequency of regeneration of the diesel particulate filter.

The present disclosure relates to a method of reducing regeneration frequency of a diesel particulate filter in a vehicle combusting diesel fuel. The method includes combusting a diesel fuel in a vehicle engine having a diesel particulate filter and wherein the diesel particulate filter requires regeneration thereof. The diesel fuel has less than about 50 ppmw of sulfur and one or more select additives to reduce a measured frequency of regeneration of the diesel particulate filter.

The composition of the present invention related to a quaternary ammonium salt detergent and the use of such quaternary ammonium salt detergents in a fuel composition to reduce diesel injector deposits and remove or clean up existing deposits on the diesel injectors.

This disclosure relates to anti-agglomerant low dosage hydrate inhibitors that can inhibit the formation of hydrate agglomerants and/or plugs. Thus, provided herein are carboxy alkyl ester compounds that can be used in hydrate inhibitor compositions and methods of inhibiting formation of hydrate agglomerants in a fluid comprising water, a gas, and optionally a liquid hydrocarbon. Also provided herein are methods of making the carboxy alkyl ester compound.

The present technology is related to imide containing quaternary ammonium salts having a hydrocarbyl substituent of number average molecular weight ranging from 300 to 750, and the use of such quaternary ammonium salts in fuel compositions to improve the water shedding performance of the fuel composition.