Hydrogenation device of methanation reactor

The utility model discloses a hydrogenation device of a methanation reactor, and belongs to the field of ethylene production equipment. The hydrogenation device comprises a methanation reactor (1) and a carbon 2 reactor (3) which are connected front and back, wherein a hydrogen outlet of the methanation reactor (1) is communicated with an inlet of the carbon 2 reactor (3), and a hydrogen inlet of the methanation reactor (1) is connected with a hydrogen outlet of a pyrolysis gas cold box (9). The hydrogenation device of the methanation reactor is characterized in that the hydrogen inlet of the methanation reactor (1) is further connected with a hydrogen outlet of a styrene production device through a pipeline provided with a valve. When the ethylene production equipment is overhauled and shut down, hydrogen of the styrene production device is adopted to guarantee the reaction of the methanation reactor and the carbon 2 reactor, qualified ethylene is extracted at the utmost, displacement material waste is avoid