Anaerobic fermentation tank

The utility model discloses an anaerobic fermentation tank. The anaerobic fermentation tank comprises a tank body of a cylindrical structure and a cone-vertex-shaped cover body installed at the upper portion of the tank body. The four edges of the cover body are connected with the tank body in a sealed mode. A vertical stirrer is arranged in the tank body, the top of the vertical stirrer penetrates through the center of the cover body, a drive motor is arranged at the upper portion of the cover body to drive the vertical stirrer, the vertical stirrer comprises a vertically-arranged drive shaft, and horizontal blades and vertical blades installed on the drive shaft, the vertical blades are installed at the upper half portion of the drive shaft, the two sets of horizontal blades are installed at the middle portion and the lower portion of the drive shaft respectively, and an annular heating pipeline is arranged on the inner wall of the tank body. The anaerobic fermentation tank is reasonable in structural layout, fermentation efficiency is improved due to the fact that stirring and heating are simultaneously conducted, real-time protection is achieved through a negative pressure protective pipe, real-time monitoring is achieved through an observation window, and use safety of the fermentation tank is guaranteed.