Effect of CO2 and H2O on gasification dissolution and deep reaction of coke

Abstract

To more comprehensively analyze the effect of CO2 and H2O on the gasification dissolution reaction and deep reaction of coke, the reactions of coke with CO2 and H2O using high temperature gas–solid reaction apparatus over the range of 950–1250°C were studied, and the thermodynamic and kinetic analyses were also performed. The results show that the average reaction rate of coke with H2O is about 1.3–6.5 times that with CO2 in the experimental temperature range. At the same temperature, the endothermic effect of coke with H2O is less than that with CO2. As the pressure increases, the gasification dissolution reaction of coke shifts to the high-temperature zone. The use of hydrogen- rich fuels is conducive to decreasing the energy consumed inside the blast furnace, and a corresponding high-pressure operation will help to suppress the gasification dissolution reaction of coke and reduce its deterioration. The interfacial chemical reaction is the main rate-limiting step over the experimental temperature range. The activation energies of the reaction of coke with CO2 and H2O are 169.23 kJ·mol−1 and 87.13 kJ·mol−1, respectively. Additionally, water vapor is more likely to diffuse into the coke interior at a lower temperature and thus aggravates the deterioration of coke in the middle upper part of blast furnace.