الفهرس 
A case study of material and energy balance of STEEL making in electric Arc furnace from DRI : a case study
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Abstract
The production of steel is an energy intensive process and the Electric Arc Furnace
(EAF) is considered the largest electric energy consumer in the industrial sector. With
the significant growth of the EAF production, the share of electricity demand in the steel
industry is expected to increase from 10% in 2012 to 22% in 2040 [1]. The electric energy
consumption in the EAF is about 65% of the total energy supplied, while the reset is
produced from the oxy-fuel burners and the chemical energy during melting and refining
[2, p. 1].
The Direct Reduced Iron (DRI) percentage in the charge is a very important factor
influencing the EAF productivity, yield, as well as operating costs. A brief comparison
between the most significant EAF parameters with the variation of DRI percentage is
presented to investigate the effect of the DRI on them. Such parameters are Electric
energy demand, Carbon combustion, Oxy-Fuel burner energy, HDRI Energy, and Power
on time. To fully define the EAF parameters, mass and energy balance of the EAF were
implemented on 160 tones tapping capacity EAF charged with DRI and Scrap. An exergy
analysis is implemented as well to determine the EAF potential and to estimate the
maximum available work that the EAF benefit from it.
Due to the presence of FeO in the DRI, which absorbs additional heat since the
reaction is endothermic, the electric energy consumption increases appropriately with the
increase of the DRI. The electric energy consumption for 100% scrap heats was 431.15
kWh/t and it increased to a maximum value of 565 kWh/t at around 70% DRI. The role
of the HDRI in reducing the electric energy arises when its quantity increases with the
increase of the DRI percentage through supplying heat resulting electric energy
consumption of 539.30 kWh/t at 100% DRI since it is charged with temperatures ranging
from 400°C to 600°C. Similarly, the power on time has a quite relation with the DRI
percentage. scrap heats have a shorter power on time than DRI heats because the process
of reducing the FeO in the DRI takes more time.
The carbon content of the DRI has a considerable influence on the chemical energy
use since it aids in the reduction of FeO. The greater the quantity of carbon in the DRI
than the amount required to lower the FeO in the DRI, the greater the necessity for the
addition of oxygen, resulting in a more increase in chemical energy. As the cases in this
study has a positive equivalent carbon, the carbon injection was a positive factor for the
energy. The increase of the energy supplied through the combustion of carbon by means
of the positive equivalent carbon is typically from 20.68 kWh/t at 0% DRI to 67.73 kWh/t
at 100%. The oxy-fuel burners energy on the other hand has a reverse affect with DRI
fraction, it ranges from 30 kWh/t at 100% Scrap to 22 kWh/t at 100% DRI