An autoclave with an upper hatch and a bottom hatch is terminated with elliptical end caps has an agitator placed inside it. The autoclave is inclined in relation to the ground plane. An external jacket is mounted on the cylindrical section of the internal pressure chamber. The jacket is divided into pressure-separated parts Inside the internal pressure chamber a paddle agitator shaft is mounted. The agitator mounting arrangement is out-of-alignment in relation to the axis of symmetry of the autoclave cylindrical section The size of the shift does not exceed ⅔ of the radial length of the cross-section of the cylindrical section of the internal pressure chamber. The agitator's paddles has two shields shifted in the agitator's axis of symmetry in relation to its paddle by a phase angle equal to 90°. The shield height does not exceed ⅓ of the height of the agitator's paddle.
