Discrete element simulation for the loading of a steep incline side wall conveyor

Abstract

The blast furnace progress team evaluated the equipment operational life of the two different charging systems used at the blast furnace plant. It was determined that the steep incline sidewall conveyor charging system had a lower operational life due to damages caused by the constant spill of material during operation. A need was identified for a discrete element model that can simulate the loading point of the steep incline sidewall conveyor, and then used to evaluate possible design changes to reduce the spilled material percentage. The development of the discrete element model simulation was initiated by determining the applicable material model parameters, and the methods used to calibrate them. A combination of the direct and bulk calibration approaches along with the V-model methodology was used. A test rig was built which allowed for a screened material sample to be drained through a containment hopper, interact with a deflection plate and settle to the material angle of repose. These events were captured with a high speed camera and the footage was used for the validation of the material parameters within the discrete element model simulation. Following the model material parameter calibration, the steep incline sidewall conveyor model was developed. This was done by firstly evaluating the plant equipment layout and operational strategy. The conveyor movement was incorporated into the simulation with the use of the overset mesh tool. The validation of the simulation model was done with the use of high speed camera footage of the loading point. Three categories of validation were established, namely particle speed assessment, particle trajectory assessment and particle-belt interaction assessment. The model was then used to determine if plant design changes can be made in order to reduce the material spillage percentage. This was done by evaluating two different modification options. Firstly the effect of a variable speed drive installation was investigated by simulating a belt velocity increase and decrease of 50%. Secondly the effect of material particle velocity variation was simulated by increasing and decreasing the discharge chute angle with 10 degrees respectively. It was determined that the chute angle modification had the greatest effect on the material spillage reduction. It was concluded that the combination of the direct and bulk calibration approaches were applicable in calibrating the required material model parameters. The discrete element model accurately simulated the loading point of a steep incline sidewall conveyor. The simulated results indicated that the spillage percentage can be reduced significantly if the material's relative velocity is matched to the belt velocity by increasing the discharge chute angle.