Optimizing the trajectory of aggregates in drying units from the asphalt plants

Abstract

The direct rotary dryers used for drying and heating the aggregates in the asphalt production stations are based on the direct contact between the material and the combustion products. The internal surface of the rotating drum is provided with flights that lift the aggregate from the bed and throw it through the air flow in a cascading motion, in order to increase the efficiency of heat transfer. The performance of rotary dryers depends, to a large extent, on the degree of dispersion of the powdery material, which the equipment is able to ensure. In this paper, the authors simulate the working process of the drying drum by highlighting the trajectories of the aggregate particles inside the equipment. Using the numerical method with discrete elements (DEM), for different combinations of operating parameters (drum filling degree, drum rotation speed) the efficiency of aggregates dispersing is determined and the optimal operating conditions of the installation corresponding to a certain type of aggregate are established.