An oil-replacement additive for two-stroke engine fuel capable of reducing fuel consumption, enhancing combustion and reducing emissions comprises boron and a carrier, wherein the boron concentration in said additive is in the interval of 100 to 600 ppm, the carrier comprises an alcohol, the amount of oil in the additive is less than 10% (w/w), and the balance is a fuel. Most preferably said additive is substantially oil-free. A two-stroke fuel comprising said additive, and a significantly reduced amount of oil, or substantially no oil, said fuel having a boron concentration in the interval of about 1 to 12 ppm.

An oil-replacement additive for two-stroke engine fuel capable of reducing fuel consumption, enhancing combustion and reducing emissions comprises boron and a carrier, wherein the boron concentration in said additive is in the interval of 100 to 600 ppm, the carrier comprises an alcohol, the amount of oil in the additive is less than 10% (w/w), and the balance is a fuel. Most preferably said additive is substantially oil-free. A two-stroke fuel comprising said additive, and a significantly reduced amount of oil, or substantially no oil, said fuel having a boron concentration in the interval of about 1 to 12 ppm.

A method for making a catalyst composition that includes a reduction catalyst mixture including a first reduction catalyst and a second reduction catalyst, wherein said first reduction catalyst comprises mixed vanadium oxides and phosphorus oxides, wherein said mixed vanadium and antimony oxides comprises V.sub.4Sb.sub.6O.sub.8, and wherein said second reduction catalyst comprises vanadium and antimony oxides; and an oxidation catalyst comprising ferrocene. The method includes selecting an organic petroleum distillate-soluble solvent that is effective to act as a reducing agent; introducing finely ground V.sub.2O.sub.5 and aqueous H.sub.3PO.sub.4 into said selected organic petroleum distillate-soluble solvent to make a first mixture; adding finely ground V/Sb oxide catalyst to said first mixture to make a second mixture; bringing the second mixture to a boil; cooling the second mixture; and adding the ferrocene or other organometallic Fe-source material to the cooled second mixture to make the catalyst composition.

Compositions corresponding to marine diesel fuels, fuel oils, jet fuels, and/or blending components thereof are provided that include at least a portion of a natural gas condensate fraction. Natural gas condensate fractions derived from a natural gas condensate with sufficiently low API gravity can provide a source of low sulfur, low pour point blend stock for formation of marine diesel and/or fuel oil fractions. Natural gas condensate fractions can provide these advantages and/or other advantages without requiring prior hydroprocessing and/or cracking.

Compositions corresponding to marine diesel fuels, fuel oils, jet fuels, and/or blending components thereof are provided that include at least a portion of a natural gas condensate fraction. Natural gas condensate fractions derived from a natural gas condensate with sufficiently low API gravity can provide a source of low sulfur, low pour point blend stock for formation of marine diesel and/or fuel oil fractions. Natural gas condensate fractions can provide these advantages and/or other advantages without requiring prior hydroprocessing and/or cracking.

The processes and systems herein described enable the use of CO.sub.2 to handle heavy oil fractions. A significant reduction in the requisite energy to maintain such a fuel in fluid form is attained. The energy reduction from herein described residue handling systems facilitate increased combustion plant efficiency and reduced CO.sub.2 emissions. The residue handling system is useful in refineries, power generation plants and other processes utilizing heavy oil residues as a feed.

An additive composition for liquid fuels is provided. The additive composition comprises water, one or more mineral salts, a polyol compound, an alcohol and a surfactant. The additive composition can be added to liquid fuels such as gasoline, diesel, kerosene and mazut to improve fuel efficiency and reduce emissions. The composition can be prepared from all natural materials.

The present invention includes a fuel injection amount sensor for detecting an injection amount of oil, a pretreatment desulfurization agent injection amount sensor for detecting an injection amount of a pretreatment desulfurization agent, and a control panel for controlling and monitoring the injection amount of the pretreatment desulfurization agent so that the predetermined desulfurization agent is mixed with the fuel in a predetermined mixing ratio. The fuel injection amount sensor is disposed on a fuel supply line between a fuel tank and a marine engine, and the pretreatment desulfurization agent injection amount sensor is disposed between a downstream fuel supply line installed downstream of the fuel injection amount sensor and a pretreatment desulfurization agent tank.

Proposed is a pretreatment desulfurization system including a desulfurization agent storage tank for storing a liquid-phase pretreatment desulfurization agent and a metering pump for supplying the liquid-phase pretreatment desulfurization agent from the desulfurization agent storage tank to a fuel supply line through which marine fuel oil is supplied to a marine engine in a predetermined ratio. Since a fluid mixture composed of the marine fuel oil and the pretreatment desulfurization agent is supplied to the marine engine, sulfur oxides are adsorbed and removed during combustion of the fluid mixture.

Proposed is a pretreatment desulfurization system including a desulfurization agent storage tank for storing a liquid-phase pretreatment desulfurization agent and a metering pump for supplying the liquid-phase pretreatment desulfurization agent from the desulfurization agent storage tank to a fuel supply line through which marine fuel oil is supplied to a marine engine in a predetermined ratio. Since a fluid mixture composed of the marine fuel oil and the pretreatment desulfurization agent is supplied to the marine engine, sulfur oxides are adsorbed and removed during combustion of the fluid mixture.