Study on the separation performance of a decanter centrifuge used for dewatering coal water slurry

The decanter centrifuge is widely used in the dewatering process of coal water slurry. In order to improve the separation performance of the decanter centrifuge, the influence of pitches, spiral blade inclination angles and rotational speeds on the separation performance was obtained by the combination of simulation and theoretical analysis. The results indicate that the higher pitch would lead to the decrease of the sediment stack height in front of the spiral blade and the residence time of the particles. With the increase of the pitch, the axial thrust and the slag solid content rate are increased first and then decreased. The best pitch is 258 mm. Using a backward tilting spiral blade can improve the distribution of sediment and enhance the radial extrusion of the spiral blade to sediment. Increasing the rotational speed can increase the tangential velocity and settling velocity of the material. When the rotational speed is less than 3000 rpm, increasing the rotational speed can improve the separation performance effectively. This paper provides references for optimizing the structure and improving the separation performance of the decanter centrifuge in the dewatering process of coal water slurry.