Research on the dry screening characteristics of fine coal based on the discrete element method

To improve the dry screening efficiency of high-moisture, high-viscosity fine coal, this study investigates the particle distribution behavior and screening performance of a variable-amplitude multi-section vibrating screen using a combination of the discrete element method (DEM) simulation, prototype testing, and response surface methodology (RSM). A clear research workflow is established: first, the parameter ranges are determined via single-factor tests; second, the optimal combination is obtained using Box-Behnken design (BBD) based RSM; finally, the optimal results are verified through prototype experiments. The optimal screening conditions were identified as four screen sections, a productivity of 17.30 t/h, and an amplitude difference of 1.50 mm. Under these conditions, the RSM predicted screening efficiency was 93.10% with a mismatch content of 4.20%. Prototype tests gave an average efficiency of 92.62% and mismatch content of 4.27%, indicating good agreement and suggesting the effectiveness of the proposed approach for large-scale fine coal screening.