Energy Conservation in Blast Furnace: Analysis on the Replaceability of Coke with Varying Reactivity and Postreaction Strength

Currently, coke with significant differences in CRI/CSR (coke reactivity index and coke strength after reaction) can already be effectively utilized in blast furnaces (BFs). However, there remains a considerable controversy on the replaceability of high and low CRI/CSR coke. Therefore, an analysis was conducted on the metallurgical performance of C1, C2, and C3(CRI:C3 > C2 > C1&CSR:C3 < C2 < C1) through simulated BF under the ore-coke coexistence (OCC) experiment. The behavior of solution loss and degradation, reduction, and thermal function of coke was investigated, and the difference of C1 ∼ C3 was quantified through deviation analysis. The findings are as follows: opposite to the result of CRI/CSR testing, the solution loss and degradation behavior of the cokes is similar under OCC. This behavior results in roughly equivalent impacts of coke on the gasification point, indirect and direct reduction. Thermodynamic analysis reveals that there is minimal difference in heat flux trend, particularly within key temperature zones. The deviation analysis result of C2 and C3 comparing to C1 is less than 5%. Therefore, it can be inferred that coke exhibiting significant variations in CRI/CSR may demonstrate same metallurgical performance. Based on this inference, the replacement of C2 and C3 to C1 in BF production could be considered as a potential strategy to optimize resource utilization and cost saving.