Modeling Carbon Composite Briquette Reaction Under H₂-H₂O-CO-CO₂-N₂ Atmosphere

Charge carbon composite briquette (CCB) is an effective method to reduce CO₂ emissions and save energy in blast furnace (BF) ironmaking. Presently with the hydrogen-bearing gas being injected in the BF, the content of H₂ and H₂O in the BF gas is comparable to those of CO and CO₂, and they could not be ignored in analyzing the CCB reaction behavior in the BF shaft. In this research, a mathematical model was developed for analyzing the reaction behavior of CCB under the H₂-H₂O-CO-CO₂-N₂ atmosphere. The model was one-dimensional. Chemical reactions, internal gas diffusion, and mass transfer between the CCB and the atmosphere were considered in the model. Using the model, the influence of gas composition and temperature on CCB reaction was discussed and the reaction progress was investigated. The simulation results showed that increasing temperature or increasing hydrogen in the atmosphere can prompt the reduction of iron oxide and the gasification of carbon in CCB. In the investigated temperature range, iron oxide reduction by hydrogen and carbon gasification by water vapor played important roles in the CCB reaction process.