EAF in Global Steel Production; Energy and Productivity Problems

Abstract

In modern EAFs electrical energy consumption is on the average about 375 kWh per ton of liquid steel. Such high electrical energy consumptions cannot be justified as EAFs have great potentials of a deep substitution of much cheaper and affordable energy of natural gas for electrical energy. The entire heat in an EAF can be divided into three stages: the heating of scrap up to an average mass temperature of 1000–1100°; further heating and melting down of scrap; and finally, heating the melt to a tapping temperature. At the typical tapping temperature, the enthalpy of liquid metal amounts to on the average 400 kWh/t; and the enthalpy of scrap at a temperature of 1050 ℃ is about 200 kWh/t. Thus, 50% of the total energy transferred to the scrap and the liquid bath during the process is consumed at the first stage where, unlike the subsequent stages, the use of electrical energy is not absolutely necessary. To heat a scrap to a temperature of close 1000 ℃ it is necessary to use the energy of fuel instead of electrical energy. This would allow reducing electrical energy consumption by a factor of 1.8.