TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The desulfurized kerosene is introduced into the modifier at a temperature below 350 degrees C. The sulfur content in the desulfurized kerosene is 0.1 weight parts/million (wt.ppm). Desulfurization is carried out at a temperature less than 230 degrees C using a desulfurizing agent containing nickel and/or copper. The temperature of water vapor mixed with the desulfurized kerosene is 200-340 degrees C, and the ratio of water vapor mixed with kerosene is 1.5 or more. The vaporizer is an ejector. The temperature of the mixture of kerosene and water vapor is 150-300 degrees C. The modification catalyst used for kerosene modification is ruthenium type catalyst containing ruthenium component and cobalt component and/or nickel component carried by an alumina carrier containing cerium oxide. The hydrocarbons in the kerosene is modified. Hydrogen is removed from fuel-cell water component. EXAMPLE - 49.8 g of nickel nitrate and 10.3 g of copper nitrate were dissolved in 500 ml of water, and heated at 180 degrees C at normal pressure, to get desulfurizing agent. The solution was then added to 0.9 g pseudo-boehmite (carrier), and 20 ml of nitric acid aqueous solution was added, such that the pH was adjusted to 1. Solution A was prepared. 33.1 g of sodium carbonate was dissolved in 500 ml of water, and 11.7 g of liquid water glass containing 29% SiO2 was added to prepare liquid B. Liquid A and liquid B were heated at 80 degrees C and mixed for 1 h by constant stirring. The liquid was filtered, washed and dried for 12 h at 120 degrees C to get a solid substance. The obtained desulfurizing agent containing 61 weight% of nickel and 19.8 weight% of copper was added to silica-alumina carrier (Si/Al ratio = 5), and baked for 1 h at 300 degrees C. Desulfurization process was carried out in vitro at 300 degrees C and the hydrogen was reduced. Water vapor generated in a water vapor generator by heating water at 320 degrees C, was mixed with desulfurized kerosene in a vaporizer, and the mixture was vaporized. The vapor mixture containing desulfurized kerosene and water vapor was then introduced into a modifier containing modification catalyst. The modification catalyst was a ruthenium trichloride solution adsorbed on alumina carrier (containing 80 mass% of alumina and 20 mass % of cerium oxide). The ruthenium catalyst contained 39.16 mass% of ruthenium contents, 4.3 g of Co(NO3)2.6H2O, and 9.1 g of magnesium nitrate (Mg(NO3)2.6H2O), dissolved in 25 ml pure water. The catalyst was dried for 3 h at 80 degrees C using a rotary evaporator. Hydrogen generated by the reaction was removed, and the process was carried out for 1000 hours. The obtained desulfurized and modified kerosene was found to contain less than 0.02 weight% of sulfur.