Effect of Coal Size Segregation in Coal Bin on Discharging Coke Cake

Abstract

For improving the performance of discharging coke cake from oven chambers, the way to increase clearance between coke cake and oven wall near coke side was investigated. To avoid a pushing trouble is needed because this trouble, which has increased gradually with the aging of coke ovens, negatively affects the stable coke production and service life of coke ovens. One of the effective approaches to improve the discharging conditions is to maintain the sufficient clearance especially near coke side because the oven walls around there have been most damaged in aging coke ovens. Therefore enlarging the clearance near coke side was studied.For this objective, it was focused on the way to decrease coal size and bulk density locally by controlling the coal size segregation in coal bin. Firstly, the effects of coal size and bulk density on the clearance were examined at laboratory. Then the effects of the charging conditions of coal blend on the size segregation and the clearance were investigated. As a result, the clearance increased with decreasing the coal size and bulk density. Moreover, the clearance was capable of variation by size segregation.Based on the laboratory-scale study, a commercial plant trial was conducted. Consequently, it was clarified that the discharging behavior was improved by size segregation although the variation of the coal size was smaller than we initially envisioned.