Isothermal methanation device for preparing synthesized natural gas

The utility model discloses an isothermal methanation device for preparing synthesized natural gas, comprising a protecting bed GB, a methanation device, a methanation heat recovery steam preparation device and a condensate treating device, wherein the methanation device comprises a first thermal insulation methanation reactor, an isothermal methanation reactor, a first heat recovery device, a second heat recovery device and a pressurization circulation device; the outlet of the protector bed is divided into two paths of pipelines, wherein one path of pipeline is connected with an inlet of the first thermal insulation methanation reactor, the second path of pipeline is connected in parallel with an outlet of the first heat recovery device, and then is connected with the inlet of the isothermal methanation reactor. The outlet of second heat recovery device is divided into two paths, one path is connected with the methanation heat recovery steam preparing device, while the other path is connected with the inlet of the first thermal insulation methanation reactor through the pressurization circulation device. The utility model is provided with advantages of energy-saving, environmental-friendly and little investment.