Vacuum Degassing Exhaust Gas Analysis for Oxygen Estimation
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Solution Overview
Problem
Existing methods for estimating oxygen concentration in molten steel during vacuum degassing treatment are not applicable to vacuum degassing lines due to differences in air pressure and flow rate, and lack accuracy in determining the proportion of blown oxygen dissolved in the steel.
Innovation Solution
A state estimation method that classifies exhaust gas sources into blown oxygen and air entering the vacuumized region, estimating their constituent ratios using N2 gas content, and calculating the dissolution rate and concentration increase of blown oxygen in molten steel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If oxygen blowing is performed to increase oxygen concentration in molten steel, then the oxygen concentration increases, but it becomes difficult to accurately determine the proportion of blown oxygen dissolved in the steel due to multiple oxygen sources
Solution Approach 1:
The exhaust gas is segmented into multiple source components: air entering the vacuumized region, CO gas from decarburization, CO2 gas from oxidation reactions, and inert gas. By measuring the flow rates and component concentrations of each gas source separately and calculating their contributions to oxygen supply, the method isolates the contribution of blown oxygen to the total oxygen concentration increase, thereby resolving the measurement accuracy problem
Solution Approach 2:
The method uses real-time measurement of exhaust gas composition and flow rate as feedback to continuously calculate and update the oxygen supply from each source. This feedback mechanism allows dynamic determination of the dissolved oxygen proportion from blown oxygen, maintaining measurement accuracy even as process conditions change
2Measurement precision
If exhaust gas measurement is used to determine oxygen discharged from the exhaust system, then the dissolution rate of blown oxygen can be estimated, but the method lacks accuracy for vacuum degassing lines due to differences in air pressure and flow rate compared to converter processes
Solution Approach 1:
The method adapts to vacuum degassing conditions by changing the measurement and calculation parameters to account for low air pressure and specific flow rate characteristics. By measuring actual exhaust gas composition and flow rate under vacuum conditions and using these parameters in the oxygen balance calculation, the method achieves accurate dissolution rate estimation specific to vacuum degassing processes
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 highly accurate state estimation of oxygen concentration in molten steel, allowing precise control of steel components and temperature during vacuum degassing treatment.
Implementation Method 1
the reaction in which carbon in the molten steel reacts with oxygen in the molten steel to generate CO gas
Implementation Method 2
time-series exhaust gas measured values including a flow rate of exhaust gas discharged from a vacuum degassing line that performs the vacuum degassing treatment and component concentrations of CO gas, CO2 gas, and O2 gas contained in the exhaust gas
Implementation Method 3
The amount of oxygen supplied from air can be determined by calculating the amount of N2 gas contained in the exhaust gas
Data Source
AI summary
Provided are a state estimation method for vacuum degassing treatment, etc. capable of highly accurate state estimation in vacuum degassing treatment. A state estimation method for vacuum degassing treatment includes: an input step (S1, S2) of receiving input of operation track records related to manipulated variables during vacuum degassing treatment and time-series exhaust gas measured values including a flow rate of exhaust gas discharged from a vacuum degassing line that performs the vacuum degassing treatment and component concentrations of CO gas, CO2 gas, and O2 gas contained in the exhaust gas, as input information; and a calculation step (S3) of, based on the input information, classifying sources of gases that constitute the exhaust gas into a plurality of sources including blown oxygen and air entering a vacuumized region in the vacuum degassing line before or during the treatment, and estimating a constituent ratio of the classified plurality of sources.