Electric Arc Furnace Conversion to BOF via Refractory Shaft
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Solution Overview
Problem
Electric arc furnaces are limited in their ability to handle higher liquid inputs due to their design, which leads to spattering of steel and slag adhering to the cover, preventing it from being opened and necessitating a conversion to accommodate increased molten iron use.
Innovation Solution
Converting an electric arc furnace into a converter by replacing the water-cooled cylindrical wall with a refractory-lined shaft section and a conical hat, incorporating side-wall injectors for oxygen or burner use, allowing for higher liquid inputs while maintaining the hearth part unchanged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxygen is blown onto molten pig iron through top-loading nozzle or door lances in an electric arc furnace, then carbon content is reduced, but steel and slag spatter adheres to the lid preventing it from being opened
Solution Approach 1:
The harmful function of spatter adhering to the lid is eliminated by removing the lid entirely and replacing it with a hat structure that remains open at the top, allowing charge material to be added without the lid welding shut during oxygen blowing operations
Solution Approach 2:
Instead of using a closed lid that must be opened, the invention inverts the approach by using a hat structure that is inherently open at the top, reversing the conventional converter design to suit the electric arc furnace's loading requirements
2Adaptability or versatility
If water-cooled cylindrical wall is replaced with refractory-lined shaft section and conical hat, then conversion to converter mode is achieved, but device complexity increases
Solution Approach 1:
The upper furnace is divided into two distinct segments: a refractory-lined shaft section for structural support and a separate conical hat for process functions, allowing each component to be optimized independently and facilitating easier conversion and maintenance
Solution Approach 2:
The conical hat structure serves multiple functions: it defines the furnace geometry, facilitates charge material addition through its open top, allows exhaust gas discharge through side openings, and prevents spatter adhesion issues, making it a multi-functional component that reduces overall system complexity
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 operation with higher liquid inputs, reduces conversion time and costs, and allows for reversible conversion to adapt to changing conditions, maintaining existing downstream equipment and minimizing investment costs.
Implementation Method 1
the water-cooled, annular cylindrical wall of the upper furnace has been replaced by an upper furnace consisting of a refractory-lined shaft section
Implementation Method 2
the upper furnace is provided with injectors arranged in the side wall, which can be used as oxygen injectors or as burners
Implementation Method 3
oxygen is blown onto the molten pig iron through a lance that can be inserted through the top opening of the hat, thereby reducing the carbon content in particular
Implementation Method 4
a conical hat with openings for exhaust gas discharge, closing off the shaft section at the top, has been placed on the upper furnace
Data Source
Figure 1
AI summary
The invention relates to a conversion system for an electric arc furnace (EAF), comprising a hearth part, a water-cooled, substantially annular, cylindrical wall as an upper furnace and a cover, which can be placed onto the latter and has openings for leading through the electrodes, into a converter (BOF), wherein the water-cooled, annular, cylindrical wall of the upper furnace is replaced by an upper furnace which consists of a shaft part with a refractory lining and placed on top of the shaft part is a conical top that upwardly closes off the latter and has openings for letting out waste gas.