Abstract
The main trough of a blast furnace (BF) is a main passage for hot metal and molten slag transportation from the taphole to the torpedo and the slag handling. Its appropriate working status and controlled erosion ensure a safe, stable, high-efficiency and low-cost continuous production of hot metal. In this work, the tapping process of a main trough of a BF in the east of China was numerically studied with the help of a CFD library written in C++, called OpenFOAM, based on the use of the Finite Volume Method (FVM). The results show that turbulence intensity downstream of the hot metal impact position becomes weaker and the turbulence area becomes larger in the main trough. During the tapping, thermal stress of wall refractory reaches the maximum value of Pa at the 4 m position in the main trough. Furthermore, baffles in the main trough placed between 5.8 m and 6.2 m were found to control and reduce the impact of the turbulence on the refractory life. The metal flowrate upstream of the baffles can be decreased by 6%, and the flow velocity on the upper sidewall and bottom wall decrease by 9% and 7%, respectively, compared with the base model. By using baffles, the minimum fatigue life of the refractory in the main trough increases by 15 tappings compared with the base model, so the period between the maintenance stops can be prolonged by about 2 days.
Highlights
Published: 26 August 2021The main trough of a blast furnace (BF) is the only runner for hot metal and slag leaving the taphole and reaching the torpedo and slag handling unit, and an important place to separate slag from hot metal and desulfurize hot metal as well
The main trough of the blast furnace is the only passage for hot metal and slag leaving the taphole for the torpedo and the slag granulation unit, and an important place to separate slag from hot metal and desulfurize hot metal as well
A mathematical model based on OpenFOAM was applied to analyze the flow temperature, wall shear stress, wall thermal stress in the main trough and the influence of adding baffles
Summary
The main trough of a blast furnace (BF) is the only runner for hot metal and slag leaving the taphole and reaching the torpedo and slag handling unit, and an important place to separate slag from hot metal and desulfurize hot metal as well. By analyzing hot metal in the main trough with the Fluent software, Chang et al [5] found that the wall shear stress increases with the increase in taphole angle. Luo et al [6] argued that the turbulence level in the trough gradually increases with the flow rate at the taphole and hot metal in slag is clearly observed. Kim et al [7] analyzed the influence of the length and cross-sectional area of the main trough on the separation of slag and hot metal in it by hydraulic model experiments and found that the effectiveness of slag–iron separation decreases if the main trough is short. Temperature, pressure and thermal stress in the trough during tapping, the fatigue life of the refractory materials is predicted. By changing the structure of the main trough, reasonable estimates for optimal fatigue life of the main trough are suggested
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