AOD Carbon Endpoint Determination Using Multi-Model Flame Analysis

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Solution Overview

Problem

Current carbon endpoint values in AOD processes are unreliable and inaccurate, leading to premature sampling and prolonged process durations due to the need for restarting the AOD process to achieve target carbon levels.

Innovation Solution

A method utilizing a combination of metallurgical modeling, fuzzy logic analysis of flame parameters, and carbon vision module to calculate and compare multiple carbon concentrations in real-time, providing an improved carbon endpoint value for accurate sampling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional mathematical models are used to estimate carbon endpoint values, then the operator can obtain carbon composition estimates, but the values are unreliable and inaccurate leading to premature sampling

Engineering Contradiction:
Improvecarbon endpoint determination accuracyVSAvoidcarbon endpoint value reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines multiple independent carbon estimation models (metallurgical model, flame model, CO model) into a unified decision-making framework. Each model contributes its own carbon endpoint estimate, and the system integrates these multiple perspectives to determine the optimal sampling time, thereby improving both accuracy and reliability compared to using any single model alone.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system continuously monitors carbon composition estimates from multiple models and uses this feedback to determine when to trigger the sampling operation. The real-time comparison of carbon values from different models provides feedback that guides the operator's sampling decision, ensuring sampling occurs at the optimal moment when carbon reaches the target level.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the operator waits for accurate carbon endpoint determination, then sampling accuracy improves, but the process duration increases due to operator speculation and delayed decisions

Engineering Contradiction:
Improvecarbon sampling accuracyVSAvoidAOD process duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary calculations and comparisons of carbon endpoint values from multiple models continuously during the AOD process. This preliminary action prepares the carbon endpoint determination in advance, so that when the optimal sampling time is reached, the operator can make an immediate decision without delay or speculation, thus maintaining both accuracy and efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the operator's subjective speculation and manual judgment with an automated computational system that objectively compares carbon values from multiple models. This substitution eliminates the time loss associated with human decision-making uncertainty while maintaining high sampling accuracy through systematic multi-model comparison.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If multiple mathematical models are used to calculate carbon compositions, then estimation coverage is improved, but the variation between model values makes it difficult to determine which value to rely upon

Engineering Contradiction:
Improvecarbon estimation method coverageVSAvoiduncertainty in model value selection
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent segments the carbon estimation task into multiple independent model calculations (metallurgical model, flame model, CO model), each handling a specific aspect of carbon composition estimation. By dividing the overall estimation problem into separate model segments, the system maintains the versatility benefits of multiple approaches while managing the complexity of value selection through structured comparison and integration.

Inventive Principle:
Principle #1Segmentation

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

Enables precise determination of the carbon endpoint, reducing process duration and gas consumption by ensuring accurate carbon sampling without operator speculation, thereby improving throughput and efficiency.

Implementation Method 1

generating a flame produced by chemical reactions above the molten metal charge

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

removing carbon from a molten metal bath produced in the AOD vessel from the molten metal charge

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentUS20250388987A1Methods for Improved Carbon Endpoint Determination
Publication Date: 2025.12.25 PRAXAIR TECH INC
  • US20250388987A1 patent drawing
  • US20250388987A1 patent drawing
  • US20250388987A1 patent drawing

AI summary

The present invention generally relates to methods for determining an improved carbon endpoint concentration in an argon oxygen decarburization process. The present invention utilizes various pieces of real-time data, including parameters of the flame and soot content to estimate a carbon composition in the steel product, along with two other metallurgical models to generate corresponding carbon compositions in the steel product. A total of 3 carbon compositions are determined and continuously updated during the process. An improved carbon endpoint value is determined to be reached when at least a first value and a second value corresponding to any of the three carbon compositions are below a target carbon value. Upon such condition being satisfied, an alert notification is transmitted to enable carbon sampling to confirm that the sample has a measured carbon concentration that is below a predetermined calculated target carbon value.