Energy-efficient solutions of foundry class steelmaking electric arc furnace

Abstract

Purpose. Substantiation of solutions aimed at reducing heat losses, mainly, by refractory lining during forced downtime and by steelmaking bath in conditions of traditionally low specific power of transformer. Methodology. Mathematical modeling of heat and mass transfer processes and numerical experiment. Findings. A mathematical model of energy-technological processes in arc furnace workspace has been developed to analyze and minimize energy consumption in daily production cycle. Geometrical and operating parameters are taken into account, in particular: variation in arcs energy efficiency at evolution of wells in charge under electrodes during melting process; circulation of melt due to bubbling with inert gas through bottom porous plug; energy loss on heat accumulation by refractory, with cooling water and off-gas. Originality. For the first time, the concept of increasing energy efficiency of arc furnace has been substantiated, based on the following set of solutions: increase in specific electrical power by reducing of charge at given productivity; reduction of bath shape factor (ratio of diameter to depth) from traditional 5 up to 2.5 by deepening and, accordingly, its radiating surface; optimization of walls and roof cooled surface relative area, where massive heat-absorbing refractory lining is not used; application of energy-saving water-cooled elements with spatial structure that promotes formation of heat-insulating and heat-accumulating slag filling. Practical value. Implementation of the set of energy-efficient solutions in conditions of typical 6 and 12-t foundry class arc furnaces provides reduction in power consumption and refractory expenditure by 1315 and 2830% respectively without significant changes in production infrastructure due to reducing energy loss, mainly, for accumulation of heat by refractory lining, and intensification of heat and mass transfer processes in forcibly stirred deep bath.