Agglomeration mechanism of wet coal powder vibration screening based on discrete element method

Abstract

In order to improve the agglomeration effect of wet coal powder, maintain good self-cleaning ability of the vibrating screen mesh and increase the recovery rate of wet fine coal powder, a vibration separation screening model for wet coal powder was established based on liquid bridge theory, throwing motion principles and the Hertz-Mindlin with JKR contact model. The influence factors such as amplitude, vibration frequency, vibration direction angle and screen surface inclination angle of the vibrating screen on the agglomeration of wet coal powder on the screen surface was analyzed. Using the outlet de-screening rate as the evaluation indicator, EDEM simulation was used to analyze the variation law of the outlet de-screening rate of wet coal powder passing through the vibrating screen under different working condition parameters. The experimental platform for vibration separation screening was established to test the screening and agglomeration effects of wet coal powder under different operating conditions. The results show that, as the amplitude increases, the particle clusters become smaller. As the vibration frequency increases, the particle clusters decrease initially, then increase and decrease again. As the vibration direction angle increases, the particle clusters increase initially, then decrease and increase again. The screen surface inclination angle is directly proportional to the size of the particle clusters, and the larger the inclination angle of the screen surface, the larger the particle clusters. The reliability of the simulation model is verified by comparing the simulation results with the experimental results.