Analysis of Electrical Energy Consumption in a Novel Direct Current Submerged Arc Furnace for Ferrochrome Production

Submerged arc furnace is a smelting device with high efficiency but huge electricity consumption. A novel structure of direct current (DC) submerged arc furnace is investigated for ferrochrome production to save electric energy. For this purpose, a three-dimensional transient multi-physics model is developed to simulate the furnace. Via the model, the effects of two key variables are quantified: electrode insertion depth and operating voltage. A new criterion, i.e., SAF smelting rate ζ∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( {\zeta^{ * } } \right)$$\end{document}, is proposed to evaluate the electrical energy consumption. The effects of burden porosity and metallic oxide percentage are clarified with respect to electrical energy consumption. The results show that this DC submerged arc furnace can effectively reduce the electrical energy consumption compared with the AC submerged arc furnace. Increasing the electrode insertion depth and electric voltage, the chromium to iron ratio increases by 72.62 and 39.46 pct. Remarkably, the temperatures of the furnace burden below the anode and cathode are different. With increasing of burden porosity, the ferrochrome production ratio ω∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( {\omega^{ * } } \right)$$\end{document} decreases by 120.52 pct and ζ∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\zeta^{ * }$$\end{document} increases by 59.73 pct. Moreover, as the Cr2O3 percentage in the furnace burden increases, ω∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\omega^{ * }$$\end{document} and ζ∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\zeta^{ * }$$\end{document} increase by 9.19 and 20.17 pct, respectively. The results are analyzed in detail to understand the smelting process of DC submerged arc furnace for better furnace design.