TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In producing the hydrocarbon composition, the fresh hydrogen is introduced at a point immediately before the Fischer-Tropsch reactor in order to raise the hydrogen-to carbon monoxide ratio of the gas to about 2. The fresh hydrogen is derived from an external source of hydrogen. The hydrogen is derived from a source selected from natural gas, methane, hydrogen gas produced by bioelectricity and methane hydrate. The hydrogen is produced from natural gas or another source of methane and other light hydrocarbons by catalytic reforming. The hydrogen is produced from natural gas or another source of methane and other light hydrocarbons in a cascade formed by at least one unit for catalytic reforming and one unit for a water gas shift reaction. The method comprises: gasifying the raw-material in the presence of oxygen to produce a gas containing carbon monoxide, carbon dioxide, hydrogen and hydrocarbons possibly together with inert components; feeding the gas obtained by gasification of the raw-material into a reformer; reforming the gas in the presence of oxygen in order to increase the ratio of hydrogen to carbon monoxide in a gaseous effluent of the reformer to a value in the range of 0.5-1.5; withdrawing the gaseous effluent from an outlet of the reformer; and further increasing the hydrogen-to-carbon monoxide ratio of the gaseous effluent to a value of about 2 by introducing fresh hydrogen in it. The gasification is carried out at a first temperature and reforming at a second temperature, the second temperature being essentially higher than the first temperature. The reforming is carried out in catalyst bed reformer at a temperature in excess of 850 degrees C, preferably 900-1200 degrees C. The method comprises: gasifying the raw-material in the presence of oxygen at a temperature in excess of 1000 degrees C to produce a gas containing carbon monoxide, carbon dioxide, hydrogen and hydrocarbons possibly together with inert components; and further increasing the hydrogen-to-carbon monoxide ratio of the gas effluent to a value of about 2 by introducing fresh hydrogen into the gas. The carbon dioxide is withdrawn from the gas before it is fed into the Fischer-Tropsch reactor and used for forming carbon monoxide by a reversed water gas shift. The carbon dioxide is withdrawn from the gas downstream any gas washing process arranged before the Fischer-Tropsch reactor. The carbon dioxide is separated from the gas by membrane filtration, by pressure swing absorption or by washing with a liquid capable of absorbing carbon dioxide. Moreover, significantly all of the carbon dioxide contained in the gas is removed before it is fed into the Fischer-Tropsch reactor and used for forming carbon monoxide by a reversed water gas shift reaction by use of external hydrogen. Only a part of the carbon dioxide contained in the gas is removed and used for forming carbon monoxide by a reversed water gas shift reaction by use of external hydrogen. The external hydrogen is both fed into the gas in order to increase hydrogen-to-carbon monoxide ratio and used for forming carbon monoxide by reversed water gas shift reaction. The molar ratio between hydrogen and carbon dioxide (CO2) fed into the gas and used for forming carbon monoxide, respectively, is 0.5:1-6:1 in particular 0.9:1-4:1. The method comprises: feeding the carbon dioxide together with fresh hydrogen into the gaseous effluent of a reformer or a high-temperature gasifier in order to produce a modified gaseous effluent; and feeding the modified gaseous effluent into a reaction zone for a reversed water gas shift reaction. The reversed water gas shift reaction is carried out at a temperature in the range of 500-1000 degrees C, in particular 700-850 degrees C. Less than 20 mole%, preferably less than 5 mole% of the carbon monoxide produced the biomass raw-material is used for producing hydrogen gas for use in the Fischer-Tropsch reactor. Essentially none of the carbon monoxide produced the biomass raw-material is used for producing hydrogen gas for use in the Fischer-Tropsch reactor. The molar ratio of the fresh hydrogen fed into the gaseous effluent to the carbon monoxide produced by gasification of the biomass raw-material amounts of 0.55-2.4. The recovered hydrocarbon composition is further treated to produce a fuel or lubricant for combustion engines. The method comprises producing hydrocarbon compositions suitable for fuel applications having distillation cut points in the range of 150-300 degrees C, in particular 180-240 degrees C; and producing hydrocarbon compositions suitable for lubricant applications, the compositions having carbon numbers in the range of 30-40. The external hydrogen is fed directly into a reformer or into a reversed water gas shift reactor or into both. EXAMPLE - No suitable example given.