Combustion characteristics of pulverized coal for blast furnace: A study based on an innovative extreme temperature increase method

Pulverized coal injection into blast furnaces can reduce coke usage, significantly contributing to lowering the cost of iron production. Characterizing the combustion characteristics of pulverized coal at the blast furnace tuyere is crucial for blast furnace smelting, yet the technology for characterizing the combustion characteristics (such as burning rate) of pulverized coal in blast furnaces still needs improvement. To further investigate the combustion characteristics of pulverized coal at the blast furnace tuyere, this study proposes a new method: dynamic characterization of pulverized coal combustion under extreme temperature increase conditions. Using this new method of pulverized coal combustion experiment under extreme temperature increase conditions, three types of coal used in blast furnaces were studied. The results show that under extreme temperature increase conditions, the combustion characteristics of pulverized coal follow the combustion rules of pulverized coal at the blast furnace tuyere, with bituminous coal exhibiting superior combustion characteristics compared to anthracite coal. When the target reaction temperature is 1200 degrees C, the combustion rates of bituminous coal and anthracite coal in 5 min are 91.77% and 41.15% , respectively, while the combustion rate of mixed pulverized coal is 50.19%, which falls between the two. Additionally, increasing the oxygen content can significantly enhance the combustion rate of mixed pulverized coal. At a reaction time of 5 min, the combustion rates of mixed pulverized coal are 50.19%, 59.06%, 68.33%, and 74.68%, respectively. Furthermore, as the target reaction temperature increases, the combustion rate of pulverized coal under extreme temperature increase conditions shows a significant growth trend. Within the temperature range of 600 degrees C to 1200 degrees C, the combustion rates of mixed pulverized coal in 5 min are 25.05%, 34.94%, 42.35%, and 50.19%, respectively. The application of this new method of pulverized coal combustion experiment under extreme temperature increase conditions provides a new approach for dynamically characterizing the combustion characteristics of pulverized coal in blast furnaces.