Increasing energy efficiency of arc steelmaking furnace with electromagnetic stirring

Abstract

Electric arc furnaces (EAF), especially of foundry class, operating with a long-term technological period, are characterized by a high level of energy loss. Intensification of heat and mass transfer in steelmaking bath by pneumatic or electromagnetic (EMS) stirring contributes to increase energy efficiency of the EAF. Influence of bath shape factor (ratio of diameter to depth), which determines heat loss due to melt surface radiation, as well as, EAF energy efficiency, on generated in liquid steel EMS power, hasn’t been sufficiently studied. Aim is to improve energy efficiency of the EAF, using EMS, through optimization the bath shape. Technique consists in comparative assessment of specific stirring power by numerical modeling of electro vortex flows in liquid steel at varying bath shape factor. Scientific novelty lays in development the concept of a "deep" bath in relation to EMS. Found that decrease in the bath shape factor from traditional 5 to 2.5 is characterized by growth of power, released during EMS, by 19-36 %, more pronounced with increased current force and reduced current frequency in the stator winding. Geometrical and operating parameters, at which the EMS power exceeds the capabilities of pneumatic stirring, have been determined. Practical value is in 6-9 % reduction of technological period under EMS conditions in a "deep" bath, which allows decrease specific power consumption in melting cycle of foundry class EAF by 1.5-2 % and by 5-6 % for the EAF, operating as part of micro-metallurgical complex.