Title

NEW OPTIMIZATION MODULES FOR ELECTRODE CONTROL SYSTEMS OF AC ELECTRIC ARC FURNACES

NEW OPTIMIZATION MODULES FOR ELECTRODE CONTROL SYSTEMS OF AC ELECTRIC ARC FURNACES

Authorship

Dittmer, Björn; Rieger, Detlef; Matschullat, Thomas; Döbbeler, Arno; Krüger, Klaus

Dittmer, Björn

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Rieger, Detlef

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Matschullat, Thomas

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Döbbeler, Arno

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Krüger, Klaus

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DOI

10.5151/2594-5335-23908

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Abstract

Next steps towards maximum performance are done by systems that can measure and detect the conditions inside the furnace in order to adapt the setpoints of the melting profile accordingly. By using structure-borne sound sensors, the SonArc modules CSM and FSM measure the state of the melting process inside the furnace shell. In combination with the evaluation of the panel temperatures the optimal impedance respectively current setpoint is defined for each phase separately. Also the overall setpoint regarding transformer tap and reactor tap is controlled and optimized. In this way specific energy consumption, power-on time and furnace wear can be significantly reduced. Furthermore, during flat bath operation the foaming slag level can be automatically controlled in order to achieve a permanently high level of foaming slag. By detecting the foaming slag levels for each phase's hot-spot separately, the carbon and oxygen injection into the furnace are optimized. This results in lower carbon consumption and increased energy efficiency. The most important system for control of an AC Electric Arc Furnace (AC-EAF) is the electrode control system. Firstly, the electrode control needs to achieve a smooth melting with absolutely lowest disturbances of the electrical values. By using state of the art impedance control adapted to the characteristics of the actuation system, optimal melting can be achieved. In this way stress and wear of the mechanical and electrical parts of the furnace are reduced.

Next steps towards maximum performance are done by systems that can measure and detect the conditions inside the furnace in order to adapt the setpoints of the melting profile accordingly. By using structure-borne sound sensors, the SonArc modules CSM and FSM measure the state of the melting process inside the furnace shell. In combination with the evaluation of the panel temperatures the optimal impedance respectively current setpoint is defined for each phase separately. Also the overall setpoint regarding transformer tap and reactor tap is controlled and optimized. In this way specific energy consumption, power-on time and furnace wear can be significantly reduced. Furthermore, during flat bath operation the foaming slag level can be automatically controlled in order to achieve a permanently high level of foaming slag. By detecting the foaming slag levels for each phase's hot-spot separately, the carbon and oxygen injection into the furnace are optimized. This results in lower carbon consumption and increased energy efficiency. The most important system for control of an AC Electric Arc Furnace (AC-EAF) is the electrode control system. Firstly, the electrode control needs to achieve a smooth melting with absolutely lowest disturbances of the electrical values. By using state of the art impedance control adapted to the characteristics of the actuation system, optimal melting can be achieved. In this way stress and wear of the mechanical and electrical parts of the furnace are reduced.

Keywords

AC-EAF; Furnace optimization; Foaming slag; Structure-borne sound.

AC-EAF; Furnace optimization; Foaming slag; Structure-borne sound.