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Model-based Level-2 control of the Electric Arc Furnace
Model-based Level-2 control of the Electric Arc Furnace
comprises the on-line observation of the currentprocess state, and
the control of electrical and chemical energy input as well as of
the continuous charging ofmaterials like !" or #$"%
&tructure of dynamic mass and energy balance model
'he process observation calculates the currentstatus of the
heat, i%e% the temperature as well asweight and composition of
steel and slag% "t startswith the status of the hot heel, which is
estimatedfrom the measured tap weight of the preceding heat%'he
current heat temperature is calculated based onan energy balance%
"t considers the re(uiredmeltdown energy of all charged and
continuouslyadded materials, energy losses by radiation, wastegas,
cooling water and electrical losses, and theenergy input by
electrical energy, gas burners, andblown o)ygen% "f re(uired,
additionally the energyinput by *+ post-combustion or scrap
preheating,e%g% in a shaft furnace, is taken into account% eightand
analysis of steel and slag are determined withina mass balance% 'he
effect of all material additionsis taken into account based on
their compositionand yield, considering relevant
metallurgicalreactions%
Automatic process control calculates the set-pointsfor energy
input and material additions according tothe (uality-dependant aim
values for tap analysisand temperature of the heat, taking into
accountrestrictions and rules from the practice data% 'heelectrical
and the chemical energy input via gasburners is controlled via
operating diagrams withset-points for different power steps
according to theachieved specific electrical energy input
duringmeltdown%
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"n case of a thermal overload of the water-cooled wall panels,
the electrical power is reduced automatically%
'he feed rate of continuously added materials like !" or #$" is
calculated dynamically from a specific feedrate and the current
power input% 'hus the feed rate reflects fluctuations in the energy
supply, which avoidstheoccurrence of ice bergs%
&tructure of the model-based process control system with
engineering data, measured data from the basicautomation system and
set-points for process control
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E)ample. on-line observation of the melt temperature+n-line
applications of the process model
Ale)andria /ational &teel, Egypt
Megasteel, 0uala Lumpur, Malaysia
Marienh1tte, ra3, Austria
&aarschmiede, 45lklingen, ermany
$enteler, Lingen, ermany
