Problem: Liquid steel pool level is the most critical and closely monitored parameter in the continuous caster process. Current methods of
determining pool level drift over time and require periodic calibration.
This process is time consuming and dangerous to personnel. |
Experimental
Steel mill personnel instrumented a mold with a series
of thermocouples to determine the temperature profile of the mold during
operation. This data consisted of 16 equally spaced thermocouples along
the direction of casting. They were place approximately 0.75"
apart. The pool level must be known to within 0.125" to guarantee process
performance.
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A Continuous Caster
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Mold Thermal Model Results
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Evaluation
The pool level predicted by the thermocouple based algorithm was compared to the level measured by the existing system. The adjacent plot shows the comparison. The blue trace corresponds to the current measurement system, the green trace is the unfiltered thermocouple based measurement. The agreement is well within the desired accuracy of the system.
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Analytical
Inferring pool level from thermocouple data is not straight-forward; others have tried but been unsuccessful. The first step was to develop a finite element model of the mold to explore the thermal gradients present in the mold. The thermal profile of the steel/mold interface was estimated based on available literature. The resulting model was used to develop a proprietary algorithm that estimates the steel pool level based on the thermal profile measured by the thermocouples.
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Comparison of Level
Measurement
Techniques
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