NOVELTY - Radical extension-type cooling methanation furnace comprises a methanation outer barrel, an upper sealing head and a lower ball head (2), where one side of the lower ball head is provided with a feed gas inlet (1), and the other side is arranged with a synthesis gas outlet pipe. The inner wall of furnace and catalyst frame (5) forms an annular space. The feed gas is conveyed into an annular space via the inlet chamber (3) formed by the lower ball head. The upper sealing head is arranged with a catalyst filling port. The catalyst is added to the furnace via the catalyst filling port.    USE - Used as a radical extension-type cooling methanation furnace.    DETAILED DESCRIPTION - Radical extension-type cooling methanation furnace comprises a methanation outer barrel, an upper sealing head and a lower ball head (2), where one side of the lower ball head is provided with a feed gas inlet (1), and the other side is arranged with a synthesis gas outlet pipe. The inner wall of furnace and catalyst frame (5) forms an annular space. The feed gas is conveyed into an annular space via the inlet chamber (3) formed by the lower ball head. The upper sealing head is arranged with a catalyst filling port. The catalyst is added to the furnace via the catalyst filling port. The catalyst frame is supported on the catalyst support (4) and is arranged with an air vent of catalyst frame. The feed gas is connected with the catalyst via the air vent and is reacted with the catalyst. The central part of furnace is arranged with a central gas collecting tube. The outer barrel catalyst frame is arranged with a sleeve arranged along the axial direction of the outer barrel. The sleeve covers the catalyst frame along radial direction and forms a space with the central gas collecting tube. The synthesis gas is conveyed into a gas collecting tube via the air vent arranged on the central gas collecting tube and is discharged via the annular space formed by the discharge duct and the outlet pipe of synthesis gas. The outlet pipe of synthesis gas is arranged on the lower ball head and is connected with the catalyst. The synthesis gas outlet is arranged on the outlet pipe of synthesis gas.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the radical extension-type cooling methanation furnace.    Feed gas inlet (1)    Lower ball head (2)    Inlet chamber (3)    Catalyst support (4)    Catalyst frame (5)