Molten Iron Refining via CO2 and H2O Gas Circulation
Solution Overview
Problem
The steel industry faces challenges in utilizing low-quality raw materials due to reduced reduction rates and yield decreases, particularly with high gangue content, which are not efficiently addressed by existing decarbonization technologies like hydrogen reduction steelmaking, necessitating a more efficient process for refining molten iron.
Innovation Solution
A method involving the circulation of exhaust gases in a DRI-Smelter-BOF scheme, where CO2 and H2O gases from DRI processing and melting are collected and reused for decarbonization refining, optimizing the process by recycling gases between DRI processing and refining, and utilizing electric smelting for further reduction with carbon materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hydrogen reduction steelmaking technology is used with high-grade raw materials (DR-grade with Fe content of 67% or more), then decarbonization is achieved, but the availability and cost-effectiveness deteriorate due to limited supply and high material costs
Solution Approach 1:
The patent changes the chemical parameters of the refining process by using CO2 and H2O gas instead of traditional oxygen blowing, enabling the use of low-grade raw materials with higher gangue content while maintaining decarbonization benefits. This parameter change allows the system to adapt to varied raw material qualities.
Solution Approach 2:
The patent introduces CO2 and H2O gas as intermediary substances that facilitate the decarbonization reaction. These gases act as mediators between the low-grade raw materials and the refining process, enabling efficient carbon removal without requiring high-grade inputs.
2Adaptability or versatility
If low-quality raw materials with high gangue content are used, then material availability improves, but reduction rate and yield deteriorate
Solution Approach 1:
The patent changes the chemical environment by introducing CO2 and H2O gases that react with gangue content and carbon materials, transforming the refining mechanism to accommodate low-grade materials while maintaining or improving reduction rates and yield through controlled chemical reactions.
Solution Approach 2:
The patent converts the harmful effect of high gangue content into a beneficial process feature. The gangue content reacts with the introduced CO2 and H2O gases to form removable compounds, turning what was previously a liability into a manageable aspect of the refining process that actually aids in impurity removal.
3Loss of substance
If traditional oxygen blowing is used for decarbonization refining, then carbon removal is effective, but energy consumption and CO emissions increase
Solution Approach 1:
The patent converts the harmful CO byproduct of traditional oxygen blowing into a useful resource. The CO generated during refining is captured and reused as a reducing gas in the DRI process, transforming a harmful emission into a valuable input material that improves overall process efficiency and reduces energy consumption.
Solution Approach 2:
The patent implements a feedback loop where CO and H2 gases generated during refining are captured and fed back to the DRI processing stage. This closed-loop system optimizes resource utilization, maintains carbon balance, and reduces net emissions while improving energy efficiency throughout the steelmaking process.
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 the efficiency of molten iron refining by improving reduction rates and yield, effectively utilizing low-quality raw materials and achieving process optimization through gas circulation and decarbonization refining.
Implementation Method 1
The separating and collecting of the CO2 and H2O gas may be performed through physical adsorption or chemical absorption.
Implementation Method 2
The separating and collecting of the CO2 and H2O gas may be performed through physical adsorption or chemical absorption.
Implementation Method 3
performing decarbonization refining by blowing the collected CO2 and H2O gas into molten iron
Data Source
AI summary
In an embodiment, gas emitted during DRI processing and melting is collected and blown in refining, and gas emitted from the refining is collected and used in DRI processing, so that it is possible to circulate gas input to and emitted from each process in a DRI-Smelter-BOF (Basic Oxygen Furnace) scheme and achieve process optimization.