Numerical Analysis on Flow Behavior of Molten Iron and Slag in Main Trough of Blast Furnace during Tapping Process

Li Wang,Chien-Nan Pan,Wen-Tung Cheng

doi:10.1155/2017/6713160

Abstract

The three-dimensional model was developed according to number 4 of the main trough of blast furnace at China Steel Co. (CSC BF4). The k-ε equations and volume of fluid (VOF) were used for describing the turbulent flow at the impinging zone of trough, indicating fluids of liquid iron, molten slag, and air in the governing equation, respectively, in this paper. The pressure field and velocity profile were then obtained by the finite volume method (FVM) and the pressure implicit with splitting of operators (PISO), respectively, followed by calculating the wall shear stress through Newton’s law of viscosity for validation. Then, the operation conditions and the main trough geometry were numerically examined for the separation efficiency of iron from slag stream. As shown in the results, the molten iron losses associated with the slag can be reduced by increasing the height difference between the slag and iron ports, reducing the tapping rate, and increasing the height of the opening under the skimmer.

Highlights

Liquid phase separation plays a central role in a variety of production technologies [1]
After separation through the skimmer arrangements, the slag is directed to subsequent slag processing facilities, and hot metal is sent to a desulphurization process prior to the steel making process [6]
The full three-dimensional computational fluid dynamics composed from finite volume method and volume fraction equation in the present of natural thermal convection have been successfully developed to analyze the separation efficiency of molten iron and slag in the main trough of blast furnace

Summary

Introduction

Liquid phase separation plays a central role in a variety of production technologies [1]. It is important to reduce metal losses associated with the slag in the main trough of the blast furnace [2, 3]. Insufficient separation gives rise to technological problems in the subsequent processing of hot metal and slag in addition to the losses themselves. The trough, or main iron runner, is made of refractory material and designed to be long enough with suitable skimmer arrangements to obtain good separation of the two liquid phases of iron and slag. The mixture of molten iron and slag [4], which are continually tapped by the internal pressure of the blast furnace from the blast furnace hearth through a taphole, is separated by the density difference of fluids [5] in the downstream of main trough. After separation through the skimmer arrangements, the slag is directed to subsequent slag processing facilities, and hot metal is sent to a desulphurization process prior to the steel making process [6]

Objectives

Results

Conclusion