Transient CFD study of wet burden charging on dynamic in-furnace phenomena in an ironmaking blast furnace: Impacts and remedies

Abstract

Water content is a key parameter of feedstock quality for ironmaking blast furnaces (BFs). Wet burden may be used in BF practice occasionally, but the impacts of wet burden charging on in-furnace phenomena of BF are not yet clear, especially the transient BF performance after charging. In this study, a transient BF model is developed and used to quantify the transient in-furnace behaviours when various high moisture burden materials under different weather conditions are used. The effect of wet burden charging on the time evolution of in-furnace phenomena can be captured in terms of temperature fields, cohesive zone position, reduction degree and moisture distribution, as well as overall BF performance in terms of coke rate and top gas temperature. The results show that the coke rate is increased by 25% and the top gas temperature can be lower than 373 K (100 °C) within 1 h after charging wet burden of 4% water in ore and 10% water in coke. Then, the operation remedies in heavy rain weather are also studied and quantified. It is indicated that the decrease of oxygen enrichment to 0% in the blast and the reuse of dry burden for ~25 h can recover the BF performance by 73% and 91% in terms of top gas temperature, respectively. This model provides a cost-effective tool to study transient flow-thermal-chemical behaviours inside the BF when moisture burden is used in BFs.