Mathematical modeling of blast furnace burden distribution with non-uniform descending speed

Abstract

The burden distribution is directly related to efficiency and stable blast furnace operation. In this paper, a mathematical model for estimating the burden distribution was developed with the combination of the falling curve sub-model, stock-line profile formation sub-model and burden descending sub-model. In a blast furnace, the burden descending velocity may be non-uniform along the radial direction due to the shaft angle and non-uniform consumption of the burden material. The modifications on two existing burden descending models, i.e., geometric profile (GP) model and potential flow (PF) model are proposed to consider non-uniform descending speed. The proposed non-uniform descending models are validated with published experiment results of scaled blast furnace. The accuracy increases notably for the modified models with the non-uniform descending velocity when compared with the original uniform descending model. In addition, the GP model and PF model are compared. The results produced by the two models are very similar. For modeling the burden descending process, both the GP model and the PF model could predict the burden profile in the upper part of the shaft. However, the PF model is capable to capture the burden distribution in case of irregular wall geometry such as scab buildup and erosion of the refractory. The effects of the non-uniform descending velocity on burden distribution in blast furnace are discussed.