Method for producing synthesis gas mixture

A process for producing a synthesis gas mixture comprising hydrogen and carbon monoxide by non-catalytic partial oxidation of hydrocarbons in the presence of oxygen and carbon dioxide, the present invention relates to a method for producing a product gas mixture comprising hydrogen, carbon monoxide and carbon dioxide by feeding at least one reactant gas comprising hydrocarbons, a reactant gas comprising oxygen and a reactant gas comprising carbon dioxide into a partial oxidation reactor and reacting at a temperature of 1200 to 1550 DEG C to obtain a product gas mixture comprising hydrogen, carbon monoxide and carbon dioxide, at least a portion of the carbon dioxide is separated from the product gas mixture and recycled to the partial oxidation reactor. The method is characterized in that the carbon dioxide fed to the partial oxidation reactor comprises additionally fed carbon dioxide to obtain a product gas mixture in the partial oxidation reactor having a hydrogen/carbon monoxide molar ratio in the range of