Hot blast superheating - A scalable technology to reduce carbon consumption

Abstract

With increasing dialogue about greenhouse gas emissions, carbon taxes and the high cost of coke in blast furnace ironmaking, Hatch and Alter NRG evaluated the benefits of superheating hot blast air with plasma energy. The concept and benefits of retrofitting a cold blast mixer to superheat hot blast air will be described. A hot mixer would increase the blast air temperature above typical values achieved during the hot stove firing cycle. Installation and maintenance of the plasma torches retrofitted to the mixer is simple compared to prior schemes to install plasma torches at individual blast furnace tuyeres. Blast furnace operational scenarios are described where superheated hot blast air is used to reduce coke consumption, hot metal conversion costs and carbon dioxide emissions while increasing productivity. Hot blast superheating with plasma energy is a scalable technology. The benefit of using plasma torches to reduce coke consumption and greenhouse gas emissions increases in proportion to the total torch power installed. The impact of carbon taxes on the blast furnace operation will be presented and the ability of hot blast air superheating to mitigate the cost of a carbon tax discussed.