NOVELTY - A methane rich gas manufacturing system consists of carbon monoxide shift reaction installation (2), desulfurization installation (3), carbon dioxide removal installation (5), methanation reaction installation (4), recycle path (4d), steam introduction unit, and gas distribution unit. The carbon monoxide shift reaction installation adjusts the ratio of hydrogen and carbon monoxide contained in source gas. The desulfurization installation is capable of performing desulfurization process for removing sulfur content from the gas circulated in the inside.    USE - Methane rich gas manufacturing system (claimed).    ADVANTAGE - The system enables efficient manufacture of methane rich gas with reduced load, energy consumption amount, and feed stream amount, by economical process.    DETAILED DESCRIPTION - A methane rich gas manufacturing system consists of carbon monoxide shift reaction installation, desulfurization installation, carbon dioxide removal installation, methanation reaction installation, recycle path, steam introduction unit, and gas distribution unit. The carbon monoxide shift reaction installation adjusts the ratio of hydrogen and carbon monoxide contained in source gas. The desulfurization installation is capable of performing desulfurization process for removing sulfur content from the gas circulated in the inside. The carbon dioxide removal installation performs carbon dioxide removal process, and removes carbon dioxide from the gas circulated in the inside. The methanation reaction installation generates methane from hydrogen and carbon monoxide by catalytic reaction, and has one or more methanation reactors (4a) for generating methane rich gas. The recycle path has a structure for circulating and returning the source gas to carbon monoxide shift reaction installation, desulfurization installation, methanation reaction installation, and carbon dioxide removal installation. The steam introduction unit introduces steam into the source gas. The recycle path sends a portion of gas containing carbon dioxide from the exit portion of one of the methanation reactors to the inlet port portion of the methanation reactor of primary stage as a gas component. The gas distribution unit distributes recycle gas in the recycle path, while providing the gas sent to inlet port portion of the recycle path from one of methanation reactors for supply.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the structure of methane rich gas manufacturing system. (Drawing includes non-English language text)    Coal gasification installation (1)    Carbon monoxide shift reaction installation (2)    Desulfurization installation (3)    Methanation reaction installation (4)    Methanation reactor (4a)    Recycle path (4d)    Carbon dioxide removal installation (5)