NOVELTY - The conversion of hydrocarbon gas into hydrocarbon liquid for generating a synthesis gas, comprises producing a synthesis gas from hydrocarbon gas and carbon or its residues, treating the synthesis gas by Fischer-Tropsch process to obtain hydrocarbon liquid and a residual gas (6), and treating the residual gas by a separation process. The residual gas comprises hydrogen, carbon monoxide, carbon dioxide and hydrocarbons. The separation process produces a gas flow having hydrogen and carbon monoxide, and carbon dioxide and hydrocarbons with two carbons atoms.    USE - Useful for converting hydrocarbon gas into hydrocarbon liquids for generating synthesis gas.    ADVANTAGE - The process is simple and cost effective.    DETAILED DESCRIPTION - The conversion of hydrocarbon gas into hydrocarbon liquid for generating a synthesis gas, comprises producing a synthesis gas from hydrocarbon gas and carbon or its residues, treating the synthesis gas by Fischer-Tropsch process to obtain hydrocarbon liquid and a residual gas (6), and treating the residual gas by a separation process. The residual gas comprises hydrogen, carbon monoxide, carbon dioxide and hydrocarbons. The separation process produces a gas flow having hydrogen and carbon monoxide, and carbon dioxide and hydrocarbons with two carbons atoms. The carbon monoxide is subjected to an oxidation reaction with carbon monoxide vapor to convert carbon monoxide into hydrogen and carbon dioxide. An effluent gas is obtained from the oxidation reaction with the carbon monoxide vapor, which is mixed with the synthesis gas before treating the synthesis gas. The gas flow is heated for recovery of 60% of carbon monoxide and mixed with water vapor before the gas flow is subjected to the oxidation reaction with the carbon monoxide. The produced synthesis gas has a hydrogen/carbon monoxide ratio of more than 1.8. The synthesis gas is optionally produced by partial catalytic oxidation. The residual gas treatment is carried out in a pressure swing adsorption separation unit. Each adsorber in the pressure swing adsorption separation unit is composed of two adsorbents beds, in which first bed is composed of a mixture of silica gel, activated carbon and zeolite or carbon molecular sieves, and second bed is composed of zeolite rich in alumina. The first bed comprises titano-silicate, which has a pore size of 3.7-4.4 Angstrom .    DESCRIPTION OF DRAWING(S) - The diagram shows the process for converting hydrocarbon gas into hydrocarbon liquid:    Synthesis gas unit; (2)    Fischer-Tropsch unit; (4)    Residual gas; (6)    Gaseous flow; (12)    Boiler. (14)