Converter Side Wall Nozzles for Molten Metal Mixing Control
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Solution Overview
Problem
The control of decarburization speed in the early phase of the refining process is not sufficiently flexible due to reaction-kinetic effects, leading to unintentional ejection or foaming of molten iron and slag, and the methods used to increase mixing intensity undesirably affect the decarburization reaction.
Innovation Solution
A converter design with side wall nozzles generating a countercurrent flow of process gas within the converter vessel, which increases mixing intensity without significantly influencing the decarburization reaction, and a method to control the mixing intensity and decarburization rate by evaluating deviations from thermodynamic equilibrium and adjusting the process gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the lance tip is lowered to increase mixing intensity, then the mixing intensity increases, but the decarburization speed increases undesirably and iron oxide is removed from the slag too early
Solution Approach 1:
The invention divides the gas injection function into two separate systems: top lance for decarburization and side wall nozzles for mixing. This segmentation allows each system to perform its specific function independently without interfering with the other, resolving the contradiction between mixing intensity and decarburization speed control
Solution Approach 2:
The side wall nozzles act as an intermediary device that introduces process gas at the slag-metal interface to enhance mixing indirectly through countercurrent flow, rather than directly lowering the lance tip into the metal bath. This intermediary approach achieves mixing enhancement without the harmful side effect of accelerated decarburization
2Productivity
If the decarburization speed is increased in the early phase, then the refining process is accelerated, but reaction-kinetic effects cause molten iron and slag to be ejected or foam over
Solution Approach 1:
The invention implements a control system that continuously monitors the decarburization process and adjusts the process gas flow rate through both the top lance and side wall nozzles based on real-time measurements of carbon content and process conditions. This feedback mechanism prevents excessive decarburization speed that could lead to ejection or foaming, while maintaining optimal refining progress
Solution Approach 2:
The invention employs dynamic control of gas flow rates through the side wall nozzles and top lance, adjusting the injection parameters according to the evolving process conditions. The system transitions from static fixed-flow injection to dynamic adaptive injection, allowing the decarburization speed to be optimized at each stage of the refining process while preventing reaction-kinetic instabilities
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
This approach enhances mixing intensity, reduces the risk of overspray and foaming, and maintains a stable decarburization process, ensuring a safer and more manageable refining process without affecting the decarburization rate.
Implementation Method 1
the side wall nozzles are designed and arranged in such a way that they generate a flow of process gas into the converter vessel that runs essentially in opposite directions to one another
Implementation Method 2
the oxygen reacts with the carbon dissolved in the molten iron to form carbon monoxide (CO) and/or carbon dioxide (CO2), thereby reducing the carbon content in the molten iron
Data Source
Figure 1
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Figure 2b
AI summary
The invention relates to a converter for refining molten metal, in particular molten iron or steel, comprising a converter vessel, at least one top outlet, and at least two sidewall nozzles arranged in the sidewall of the converter vessel, characterized in that the sidewall nozzles are designed and arranged such that a substantially counter-rotating flow of process gas can be generated into the converter vessel, and a method for controlling and/or regulating the refining process with particular consideration of the conditions at the beginning of the decarburization process. Furthermore, the invention relates to a method for controlling the decarburization process of a metallic melt in a metallurgical reactor, preferably a converter according to the invention.