Effect of hydrogen gas addition on combustion characteristics of pulverized coal

A promising approach to decrease CO2 emissions from blast furnaces during ironmaking is to blow a reducing gas containing hydrogen into blast furnaces from their tuyeres. However, the combustion behavior of pulverized coal in the presence of a hydrogen-containing gas has not been elucidated. In this work, the combustion experiments of pulverized coal using a drop tube fumace were carried out to investigate the effect of H-2 gas addition on the combustibility of pulverized coal. The combustion ratio of char particles in the presence of H-2 gas (when introduced at a flow rate of 0.10 L/min) was larger than that in the absence of H-2 gas. This is because of the enhanced release of volatile matter from coal and the combustion of char due to an increase in the temperature of the coal particles, which was caused by the drastic combustion of H-2 gas. The combustion ratio of char particles when H-2 gas was added at flow rates higher than 0.21 L/min was considerably smaller than that obtained when H-2 gas was not added. It was found that the combustibility of coal was enhanced when an optimum H-2 gas flow rate was used. (C) 2017 Elsevier B.V. All rights reserved.