The Use of Electrical Technologies in Blast Furnace Ironmaking

Abstract

Extensive development work on the use of plasma torches in blast furnace ironmaking was completed in the 1980s. The technology developers planned to reduce blast furnace coke consumption using electrical energy and large scale coal injection through the tuyeres. Plasma torches were identified as an alternative technology to large scale oxygen enrichment which was considered too expensive at the time. Ultimately, plasma technologies were not implemented largely due toconcerns with plasma torch reliability in the steel plant environment. Westinghouse Plasma Corporation has since improved torch reliability with industrial experience in solid-waste-to-energy facilities, as well as metallurgical applications. Since coke makes up one-third of the hot metal cost, savings efforts frequently seek to lower coke consumption by increasing process efficiency or replacing coke with cheaper fuels. With an increasing focus on lowering greenhouse gas emissions, plasma torches offer the opportunity to lower both coke rate and carbon dioxide emissions from the blast furnace by using a greater amount of electrical energy. Alter NRG and Hatch assessed the merits of using plasma torch technology to superheat the hot blast and reduce coke consumption in blast furnace operations. Coke rate savings, coal consumption, electrical purchase requirements for hot blast superheating, and CO² emission reduction values are presented.