The invention relates to a process for utilizing a hydrocarbon-comprising and/or carbon dioxide-comprising coproduct gas, accompanying gas and/or biogas, wherein hydrocarbon-comprising and/or carbon dioxide-comprising coproduct gas, accompanying gas and/or biogas is introduced into a reaction space and the multicomponent mixture comprised in the coproduct gas, accompanying gas and/or biogas is converted in a high-temperature zone at temperatures of more than 1000° C. and in the presence of a carrier into a product gas mixture which comprises more than 95% by volume of CO, CO2, H2, H2O, CH4 and N2 and optionally into a carbon-comprising solid which is deposited to an extent of at least 75% by weight, based on the total mass of the carbon-comprising solid, on the carrier where the flow velocity of the gas mixture of coproduct gas, accompanying gas and/or biogas in the reaction zone is less than 20 m/s.