Development of the Model for Estimating Coke Fine Ratio in Blast Furnace

Abstract

Improving operation performance of blast furnaces is necessary to reduce CO₂ emissions and pig iron costs. One of the important factors for the operation is keeping gas permeability well in the blast furnace. Coke fines affect gas permeability and the operation condition become worse, therefore clarification and prediction of the generation behavior of coke fines in blast furnaces are desired.

In the present study, first of all, new evaluation method was developed to quantify coke abrasion behavior. And then, we proposed the prediction expression to estimate the amount of coke fines based on the results of abrasion experiments using new method. Finally, the distribution of coke fines in the blast furnace was numerically simulated by coupled 2D blast furnace model and Discrete Element Method (DEM) using proposed equation.

The results are summarized as follows:

1) The influential factors of coke abrasion were mechanical conditions like shear distance or compressive stress, and coke quality like strength (Drum Index, DI) or porosity. The amount of coke fines increased by rising shear distance, compressive stress and porosity or decreasing DI.

2) According to numerical simulation using these models, coke fines generated around peripheral area in lower shaft, belly and bosh. In addition, the total amount of coke fines increased with the decrease of DI. These results are in accordance with the conventional knowledge.

The distribution of coke fines in the blast furnace became predictable. This evaluation will lead optimum burden distribution and ideal coke quality to achieve highly efficient operation of blast furnaces.