NOVELTY - Forming hydrogen rich gas mixture from solid sulfur- and halogen-containing carbonaceous feedstock involves gasifying feedstock with oxygen-containing gas, where feedstock is provided as mixture of feedstock/gaseous carrier gas to form mixture of halogen/sulfur compounds, hydrogen and at least 50 vol.% carbon monoxide; contacting with quench gas or liquid and with water; subjecting to water gas shift reaction, where part or all of CO is converted with steam to hydrogen/carbon dioxide in presence of catalyst; and separating compounds by using dialkylether of polyethylene glycol as solvent.    USE - For preparing hydrogen rich gas mixture from solid sulfur and halogen-containing carbonaceous feedstock (claimed), used in chemical applications or in a process to make power e.g. as feedstock to a gas turbine e.g. in an IGCC-process.    ADVANTAGE - The method avoids need for adding significant amount of steam to the feed. The method provides a more efficient process for producing hydrogen rich gas mixture. The method requires less amount of steam; and has simplified process line-up as compared to prior art processes. The steam content of the gas mixture poor in halogen as it leaves the contactor is in the correct range to perform the water gas shift reaction. In the method, no water or steam is added to the gas mixture poor in halogen before performing the water gas shift reaction in the reactor or, in case of more than one reactor, in the first reactor of such a series of reactors. The gas mixture poor in halogen as obtained after contacting with water is directly used as feed to the water gas shift reaction.    DETAILED DESCRIPTION - Preparation of hydrogen rich gas mixture from solid sulfur- and halogen-containing carbonaceous feedstock involves: a) gasification of solid carbonaceous feedstock with an oxygen-containing gas in an entrained flow gasifier provided with at least one burner, where carbonaceous feedstock is provided to the burner(s) as mixture of solid carbonaceous feedstock and gaseous carrier gas to obtain gas mixture comprising halogen compounds, sulfur compounds, hydrogen and at least 50 vol.% carbon monoxide, on dry basis; b) contacting gas mixture with quench gas or quench liquid to reduce temperature of gas mixture to below 900 degrees C; c) contacting gas mixture obtained in step (b) with water in counter-current contactor having top end and bottom end, where water having temperature 150-250 degrees C is continuously fed to top of the contactor and the gas mixture to bottom end to obtain gas mixture comprising 50-1000 ppm halogen and having steam to carbon monoxide molar ratio of 0.2:1 to 0.9:1; d) subjecting gas mixture obtained in step (c) to water gas shift reaction, where part or all of carbon monoxide is converted with steam to hydrogen and carbon dioxide in presence of a catalyst as present in one fixed bed reactor or in series of more than one fixed bed reactors and where temperature of gas mixture as it enters reactor or reactors is 190-230 degrees C; and e) separating carbon dioxide and sulfur compounds from shifted gas mixture obtained in step (d) by contacting shifted gas mixture with a solvent comprising dialkylethers of polyethylene glycol.