Optimization of Raceway Adiabatic Flame Temperature Model for H₂-Rich Gas Injection Blast Furnace

The raceway adiabatic flame temperature (RAFT) is the basis for judging the thermal state of the hearth and an important parameter for the blast furnace (BF) operation. However, the traditional model fails to accurately characterize the actual RAFT suitable for H₂-rich gas injection BF. In this study, a RAFT heat balance model suitable for BF with injection of H₂-rich gas (shale gas, coke oven gas and H₂) was optimized. The influences of the H₂ concentrations in tuyere gases, O₂ enrichment ratio, pulverized coal injection (PCI) quantity and blast humidity on RAFT were calculated and the mathematical formula was set up through multiple linear regression. The results show that with the injection rate of coke oven gas, H₂ and shale gas, the RAFT decreases at a rate of 10.4 ℃ per kg, 14.7 ℃ per kg and 5.92 ℃ per kg, respectively. In addition, RAFT increases with the increase of oxygen enrichment ratio, while decreases with the increase of PCI quantity and blast humidity. Changing the oxygen enrichment ratio, PCI quantity and blast humidity can modulate RAFT when the H₂-rich gas is injected into BF. This work provides a reference for the H₂-rich gas injection BF.