NOVELTY - A feedstock is subjected to partial oxidation by contacting with oxygen-containing gas, to obtain gaseous mixture containing hydrogen, carbon monoxide, steam, carbon dioxide, methane and soot particles. The gaseous mixture is passed through a filter, and soot particles are retained on the filter, to obtain a mixture containing hydrogen, carbon monoxide, carbon dioxide and methane, and reduced soot particles. The retained soot particles at elevated temperature are converted into carbon monoxide. Thus, the mixture containing hydrogen and carbon monoxide is manufactured.    USE - Manufacture of mixture containing hydrogen and carbon monoxide.    ADVANTAGE - The mixture containing hydrogen and carbon monoxide is manufactured efficiently and effectively by partial oxidation process in vertically elongated reactor vessel.    DETAILED DESCRIPTION - A feedstock is subjected to partial oxidation by contacting with oxygen-containing gas, and a gaseous mixture containing hydrogen, carbon monoxide, steam, carbon dioxide, methane and soot particles at elevated temperature is obtained. The obtained gaseous mixture is passed through a filter such that the soot particles are retained on the filter, and the mixture containing hydrogen, carbon monoxide, carbon dioxide and methane, and reduced content of soot particles is obtained. The filter is a ceramic foam filter or a ceramic wall-flow filter. The retained soot particles at elevated temperature are converted into carbon monoxide. Thus, the mixture containing hydrogen and carbon monoxide is manufactured using methane-containing gaseous feed. The filter contains ceramic foam comprising porous refractory material such as alumina. An INDEPENDENT CLAIM is included for vertically elongated reactor vessel.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of vertically elongated reactor vessel.    Pressure shell (1)    Multi-layered refractory lining (2)    Burner (3)    Supply conduits (4,5)    Ceramic filter bed (7)