Vacuum Degassing Line Carbon Control Using Error Correction
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Solution Overview
Problem
Existing methods for estimating carbon concentration in molten steel during vacuum degassing are inaccurate due to errors in decarburization reaction models and measured values of exhaust gas, leading to prolonged decarburization processing times.
Innovation Solution
A control device and method that corrects errors in both the decarburization reaction model and measured exhaust gas values by using correction parameters based on an evaluation function, ensuring accurate estimation of in-molten-steel carbon concentration and timely termination of decarburization processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If decarburization reaction model is used to estimate carbon concentration, then estimation can be performed, but errors in the model and measured values lead to inaccurate estimation
Solution Approach 1:
The patent implements feedback by calculating the difference between the decarburization rate from the reaction model and the decarburization rate from exhaust gas measurements. This difference is fed back to correct the estimated carbon concentration, forming a closed-loop system that continuously improves estimation accuracy based on actual process data.
Solution Approach 2:
The patent changes the parameter estimation approach by introducing correction terms based on the difference between model-predicted and measurement-based decarburization rates. Instead of relying on a single fixed model, the system dynamically adjusts estimation parameters using real-time process data, transforming static model parameters into adaptive correction factors.
2Manufacturing precision
If excessively long decarburization processing is performed to ensure carbon concentration standards, then carbon concentration can be reduced below 10 ppm, but processing time is prolonged
Solution Approach 1:
The system uses feedback from exhaust gas measurements to continuously monitor the actual decarburization rate and compare it with model predictions. This real-time feedback allows operators to accurately determine when the carbon concentration has reached the target level, preventing both premature termination and excessive processing time.
Solution Approach 2:
The patent replaces reliance on fixed mechanical timing or operator experience with an automated estimation system that uses mathematical models and sensor data. This substitution enables precise, real-time determination of carbon concentration, allowing for optimal termination timing that meets specifications without unnecessary delays.
3Measurement precision
If decarburization rate from reaction model is used for correction, then model accuracy can be improved, but errors in the model are still reflected in estimation results
Solution Approach 1:
The patent introduces an intermediary correction mechanism that uses exhaust gas measurements as a mediator between the reaction model and the final carbon concentration estimation. The exhaust gas data serves as an independent verification that helps filter out model errors, creating a more robust estimation that combines model predictions with actual process observations.
Solution Approach 2:
The estimation system combines multiple information sources (reaction model predictions, exhaust gas measurements, and their difference-based corrections) into a composite estimation approach. This composite method leverages the strengths of each source while compensating for their individual weaknesses, producing a more accurate and reliable carbon concentration estimate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Highly accurate estimation of carbon concentration in molten steel allows for appropriate timing of decarburization processing termination, reducing processing time and improving the quality of ultra-low carbon steel production.
Implementation Method 1
placing the molten steel under a vacuum environment using a vacuum degassing line
Implementation Method 2
accelerate decarburization by placing the molten steel under a vacuum environment
Data Source
AI summary
A control device (10) for a vacuum degassing line includes an operation information input unit (11) configured to receive information regarding a weight and concentrations of components of the molten steel before the decarburization processing, track records of operation when the decarburization processing is being executed, and information regarding auxiliary raw materials; a component calculation unit (12) configured to estimate an in-molten-steel carbon concentration in the molten steel; a correction calculation unit (13) configured to calculate correction parameters to correct an estimated value of carbon content discharged from the vacuum degassing line and the estimated in-molten-steel carbon concentration in the molten steel; and a decarburization processing control unit (14) configured to end the decarburization processing when the in-molten-steel carbon concentration in the molten steel that has been corrected by the correction parameter reaches a target value.