Abstract: Methods and compositions for improving stability of biodiesel fuel. The methods comprise adding to said biodiesel fuel, an effective amount of a combined treatment that includes a (I) hindered phenol and (II) a Mannich reaction product. The compositions comprise I and II dissolved or dispersed in an organic solvent.

Abstract: A treatment for accelerating the settling of finely divided solids in hydrocarbon fluids, including adding to the hydrocarbon a sufficient settling amount of a combination of at least two of (a) a quaternary fatty ammonium compound, (b) a hetero-atom punctuated fatty polymer and (c) an alkylphenol-formaldehyde resin alkoxylate.

Abstract: A treatment for accelerating the settling of finely divided solids in hydrocarbon fluids, including adding to the hydrocarbon a sufficient settling amount of a combination of (a) a polyacrylic acid adducted alkylphenol-formaldehyde resin alkoxylate compound, and (b) an alkylphenol-formaldehyde resin alkoxylate having a molecular weight of about 500 to about 5,000.

Abstract: A treatment for accelerating the settling of finely divided solids in hydrocarbon fluids, including adding to the hydrocarbon a sufficient settling amount of a combination of (a) a polyacrylic acid adducted alkylphenol-formaldehyde resin alkoxylate compound, and (b) an alkylphenol-formaldehyde resin alkoxylate having a molecular weight of about 500 to about 5,000.

Abstract: The present invention relates to compositions to stabilize hydrocarbon fuel, over a range of alcohol and water concentrations, against phase separation, containing a blend of two or more wide or one or more wide and one or more tall gaint hydrophobe nonionic surfactants. It also relates to fuel compositions stable toward such phase separation, which include (a) a major portion of a hydrocarbon fuel; (b) a minor amount of a low-alkyl (C1-C3) alcohol; (c) a minor portion of water; and (d) a minor portion of a stabilizer comprising a blend of wide or wide and tall giant hydrphobe nonionic surfactants. Optionally, the fuel compositions also include (e) a minor amount of a combustion aid, such as a cetane improver and (f) a minor amount of a solvent, such as a water solubilizing higher (C4 to C16) alcohol.

Abstract: A treatment for accelerating the settling of finely divided solids in hydrocarbon fluids, including adding to the hydrocarbon a sufficient settling amount of a combination of at least two of (a) a quaternary fatty ammonium compound, (b) a hetero-atom punctuated fatty polymer and (c) an alkylphenol-formaldehyde resin alkoxylate.

Abstract: The present invention provides for a method and system for determining the concentration of a surfactant in a transparent hydrocarbon by performing the steps of adding a solid to the hydrocarbon; adding a second masking reagent to the hydrocarbon; mixing to form a dispersion; separating the dispersion from the mixture; and measuring the optical absorption of the dispersion.