BIOLOGICAL METHANATION REACTOR

The reactor (100) for the biological methanation of dihydrogen or a dihydrogen-rich gas and carbon dioxide or a carbon dioxide-rich gas, comprises: - an enclosure (105) having a longitudinal end (106) referred to as "low" and an opposite longitudinal end (107) referred to as "high", said enclosure comprising, near the low end: - a primary inlet (110, 405) for water, - an inlet (115, 405) for dihydrogen or dihydrogen-rich gas and - an inlet (120, 405) for carbon dioxide or carbon dioxide-rich gas and close to the high end: - an outlet (125) for synthetic methane or synthetic methane-rich gas and - a primary outlet (130) for water, - a support material (135) for forming a methanogenic flora bed, having a density less than the density of water, movable in translation along the longitudinal axis (101) of the enclosure, configured to receive a methanogenic flora and - between the support material, on the one hand, and the outlet for methane and the outlet for water, on the other hand, a surface (140) for retaining the perforated support material forming a stop for the longitudinal movement of the support material at the position of said surface.