7TH EUROPEAN COKE AND IRONMAKING CONGRESS - ECIC 2016

Briquette blend coking process (BBCP) is one of the coal pre-treating technologies. In this process, a part of coal charge is briquetted, and the briquettes thus produced are charged into a coke oven chamber with the fine coal. The briquette blend leads to an increase in a coal bulk density in the coke oven chamber, which contributes to the improvement of coke strength. In contrast, there have been several studies that the briquette blend causes a decrease in bulk density of the fine coal part. As the coal bulk density is the main factor to determine coke strength, it is important to clarify the factors which decrease the coal bulk density in the fine coal part. We proposed a method to evaluate the packing structure of the coal charge which contains the briquettes by X-rays CT device. First, in order to simulate the packing structure of coal charge in a coke oven chamber, blended coal which contains briquettes was fallen into a box (internal dimension: 150 mm square) by free-fall. Successively, we observed the distribution of coal bulk density in the box by X-ray CT device in detail. As a result, we found the low bulk density areas were formed locally around briquettes. Moreover, we proposed the method to measure the width of the low bulk density area by image analysis.