NOVELTY - Preparing synthesis gas comprises: (a) decomposing a hydrocarbon-containing fluid to carbon and hydrogen at at least 200 degrees C using a plasma; (b) mixing water with at least one portion of the obtained carbon at 800-1700 degrees C; and (c) discharging the produced synthesis gas.    USE - The synthesis is useful for preparing synthetically functionalized and/or non-functionalized hydrocarbons such as paraffin, diesel fuel, gasoline fuels, kerosene, methanol, methane and/or liquefied gases (claimed).    ADVANTAGE - The process provides synthesis gas in high yield without consuming large amount of energy.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) producing synthetically functionalized and/or non-functionalized hydrocarbons from at least one portion of the synthesis gas produced in the step (c);    (2) a device (1) for producing synthesis gas comprising a plasma operated hydrocarbon having at least one inlet for hydrocarbon containing fluid and at least one outlet (5) for carbon and at least one outlet (6) for hydrogen, a carbon-converter (9) with at least an inlet for water and at least one inlet for carbon and at least one outlet for synthesis gas, where at least one inlet for carbon of the C-converter is linked to an outlet for carbon of a hydrocarbon converter (3) via carbon-bond; and    (3) a device for producing synthetic functionalized and/or non-functionalized hydrocarbon comprising the device for producing the synthesis gas and a carbon monoxide-converter with at least one inlet for synthesis gas and at least one outlet for synthetically functionalized and/or non-functionalized hydrocarbons, where at least one inlet for the synthesis gas of the carbon monoxide-converter is connected to the outlet for the synthesis gas of the carbon-converter.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a device for producing synthesis gas (Drawing includes non-English language text).    Device for producing synthesis gas (1)    Hydrocarbon converter (3)    Outlet for carbon (5)    Outlet for hydrogen (6)    Carbon-converter. (9)