Numerical Investigation of the Coupled Effect of H/D Ratio and Effective Volume on Optimized Blast Furnace Profile

Abstract

The design and optimization of blast furnace (BF) profiles generally rely on limited empirical knowledge and experience. Such exercise can now be improved by means of process modeling and optimization. In this work, the effect of furnace profile on BF performance is numerically investigated across a wide range of furnace volumes (500 to 6000 m³), focusing on the ratio of effective height to belly diameter (H/D ratio). This is done based on the recently developed 3D multi-fluid BF process model. The results indicate that the optimized H/D ratio under different furnace volumes can be determined by minimizing the total energy consumption, namely, the summation of chemical and physical energy consumptions. Comparative analysis indicates that the industrial data on the variation of H/D ratio with furnace volume, collected over years, can be reproduced quantitatively by the current model. The increase in BF size or volume results in high thermal energy efficiency and low coke rate, primarily attributed to the reduced heat dissipation from the top gas and furnace wall. But there exists a size threshold between small and large BFs, approximately 2000 m³ under the conditions considered. Beyond this threshold, the BF performance and in-furnace states do not change significantly. Optimum BF profile needs to consider the coupled effect of H/D ratio and effective furnace volume.