Abstract: One embodiment of the present invention provides a method for increasing the amount of a hydrocarbon oil, said method being characterized by comprising mixing air-bubbled water with methanol in the presence of a catalyst to produce a mixed solution, mixing the mixed solution with a hydrocarbon oil to produce an emulsion, and bringing the emulsion into contact with a gas or an aqueous solution each containing carbon dioxide, wherein the amount of the hydrocarbon oil is increased in accordance with the reactions represented by (formula 1) and (formula 2): (1) CnHm+CH3OH?Cn+1Hm+2+H2O, (2) (1??)×(Formula 3)+?×(Formula 4), (3) CnHm+CO2+H2O?Cn+1Hm+2+3/2O2, and (4) CnHm+CO2+2H2O?Cn+1Hm+4+2O2.

Abstract: Provided are a method and a device with which carbon dioxide is used as a starting material to yield methanol, without requiring high-temperature high-pressure conditions or the addition of hydrogen, and fuel hydrocarbons such as gas oil or heavy oil are produced in a satisfactory yield. The method is a method for increasing the amount of a hydrocarbon oil, characterized by: mixing methanol with water into which air has been bubbled in the presence of a catalyst; mixing the resultant liquid mixture with the feed hydrocarbon oil to produce an emulsion; and contacting this emulsion with a gas or aqueous solution which contains carbon dioxide.