Optimization of Structural Parameters of Venturi Vertical Cooling Furnace

Abstract

Theoretically, the vertical sinter sensible heat recovery process can significantly improve the recovery rate of sinter sensible heat. However, the segregated distribution of the sinter and uneven gas–solid flow in vertical cooling furnaces result in insufficient contact and heat exchange between the high-temperature sinter and the cooling gas, thereby limiting the improvement in the sinter sensible heat recovery rate. A Venturi vertical cooling furnace can improve the contact heat transfer between gases and solids and the uniformity of the sinter and the cooling gas temperature. However, this leads to a significant increase in the gas pressure drop and affects the integrity of the downward movement of the sinter. To control the increase in the gas pressure drop while increasing the sensible heat recovery and maintaining the integral flow of the sinter, this study takes a Meishan Steel vertical cooling furnace as the research object and uses the DEM-CFD coupling model to optimize the structural parameters of the Venturi-type vertical cooling furnace. Firstly, a scaling method was designed to reduce the computational cost. Secondly, based on the on-site conditions, the selection range of structural parameters for the Venturi furnace was determined. Finally, an orthogonal experiment was designed. Taking the sensible heat recovery of the sinter and the pressure drop of the cooling gas as the main index, the integrity of the sinter flow was taken as the secondary index to study the Venturi structure parameters suitable for the Meishan Steel vertical cooling furnace, including the width of the vertical part w, the length of the vertical part l, the contraction angle of the contraction part β, and the expansion angle of the expansion part α. The results showed that the order of structural parameters affecting the sensible heat recovery was w, β, α, and l, and the order of parameters affecting the gas pressure drop was w, β, l, and α. The appropriate structural parameters of the Venturi furnace type, obtained by considering the sensible heat recovery and gas pressure drop, were w = 1.1 m, β = 16°, α = 13°, and l = 0.5 m. In addition, in order to improve the integrity of the sinter flow, it was also necessary to increase the wall friction of the particles in the central area of the vertical section by adding steel plates. The results can provide theoretical guidance for improvements to the Meishan Steel vertical cooling furnace. The operation parameters corresponding to the Venturi furnace type can be studied later.