Numerical simulation of coal briquetting process using discrete element method

During the production of formed coke from coal, the step of briquetting (compression molding) has strong effects on the structure and strength of the coke. To systematically examine important factors in the briquetting process, this study used the discrete element method to numerically simulate the loading and unloading test of an actual packed bed of coal particles. Changes in the structure inside the packed bed and the stress during compression were evaluated. X-ray CT images showed that the filling ratio was higher near the top of the bed close to the piston. According to the simulation result, this was because of the relatively stronger contact force experienced by individual particles in that part of the packed bed. The simulation also indicated that the frictional force between particles affects the distribution of the contact force acting on them, while the friction force between the particle and container wall especially influences the distributions of the contact force and the filling ratio.