Biogas fermentation tank

The utility model provides a biogas fermentation tank which comprises a rotary tank body with an open top end, the bottom end of the rotary tank body is rotatably mounted on a base, a sealing cover plate is rotatably packaged at the top end of the rotary tank body, and the sealing cover plate is positioned and fixed on the base through a press mounting frame group; a slag discharging opening is formed in the center of the bottom of the rotary tank body; a biogas slurry feeding opening and a biogas discharging opening are formed in the sealing cover plate; at least one group of reinforcing frames are fixed on the sealing cover plate, extend into the rotary tank body and are used for supporting and fixing the heating pipe group; a circulating pump is further mounted on the sealing cover plate, the feeding end of the circulating pump is connected with a pipeline I which penetrates through the sealing cover plate and extends into the bottom area of the rotary tank body, and the discharging end of the circulating