COMBUSTION BEHAVIOR OF PULVERIZED COAL IN TUYERE ZONE OF BLAST-FURNACE AND INFLUENCE OF INJECTION LANCE ARRANGEMENT ON COMBUSTIBILITY

Hot model experiments on pulverized coal injection were carried out to understand the combustion mechanism of pulverized coal injected into the blast furnace. The combustion behavior of the pulverized coal was directly observed by a high speed camera, and the temperature distribution of combustion flame was analyzed by an image processor. According to the results, the combustion flame was not uniform across the cross section of the blow pipe and tuyere, and the fluctuation of the flame was observed. Then, it was found that the dispersion of the pulverized coal had a great role on combustibility owing to the rapid consumption of oxygen by the combustion of volatile matter. Moreover, it was confirmed that the arrangement of injection lance influenced on the combustion efficiency, since the dispersion of coal particles was enhanced by the double lance arrangement. On the basis of the above results, the dispersion of coal particles was analyzed by the calculation of the average distance of individual coal particles to easily evaluate the effect of the injection lance on combustibility.