Blast Furnace Stack Wall Enlargements for Reducing Gas Injection
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Solution Overview
Problem
Blast furnaces emit significant CO2 due to high coke consumption, and existing methods to reduce emissions, such as top-gas recycling, may disrupt the ironmaking process and productivity.
Innovation Solution
A blast furnace design with internal wall enlargements in the injection zone allows for targeted injection of a CO-rich reducing gas at specific angles and speeds, reducing coke consumption and CO2 emissions without impairing productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If top gas is recycled and injected into the blast furnace to reduce CO2 emissions, then coke consumption decreases, but the ironmaking process may be disrupted and productivity impaired
Solution Approach 1:
The patent applies local quality by creating local inwards enlargements at specific positions on the internal wall of the blast furnace stack. These localized structural modifications concentrate the reducing gas injection effect at particular zones, ensuring that the gas is injected precisely where it can reduce CO2 emissions without disrupting the overall ironmaking process flow and productivity.
Solution Approach 2:
The patent implements preliminary action by pre-structuring the internal wall with local inwards enlargements before gas injection begins. This preliminary structural preparation ensures that when reducing gas is injected, it follows a predetermined path and reaches optimal injection zones, preventing process disruption while maintaining productivity.
2Object-generated harmful factors
If reducing gas is injected at the tuyere level to replace hot blast, then CO2 emissions are reduced, but the reduction zone stability may be compromised
Solution Approach 1:
The patent applies dimensionality change by transitioning from horizontal/vertical injection at the tuyere level to radial injection through the stack wall. The local inwards enlargements create a third spatial dimension for gas injection, allowing the reducing gas to enter the furnace from the stack perimeter and reach the reduction zone through a different spatial path, thereby maintaining reduction zone stability while reducing CO2 emissions.
3Speed
If reducing gas injection speed is increased to improve penetration, then gas reaches deeper into the burden, but process stability may be compromised
Solution Approach 1:
The patent applies local quality by creating localized injection zones through inwards enlargements at specific positions on the internal wall. These localized structures control and concentrate the gas injection effect, allowing high injection speeds to achieve deep penetration into the burden while the localized nature of the injection maintains overall process stability by preventing widespread disruption.
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 efficiently injects reducing gas into the blast furnace, minimizing coke use and CO2 emissions while maintaining or improving productivity by optimizing gas penetration and contact with the burden.
Implementation Method 1
the conversion of the iron-containing charge (sinter, pellets and iron ore) to cast iron, or hot metal, is conventionally carried out by reduction of the iron oxides by a reducing gas (in particular containing CO, H2 and N2)
Implementation Method 2
the reducing gas injections are performed at a speed comprised between 75 m/s and 200 m/s
Data Source
AI summary
A blast furnace for ironmaking production wherein iron ore is at least partly reduced by a reducing gas which is injected in the stack of the blast furnace in an injection zone, the blast furnace comprising an external wall and an internal wall in contact with matters charged into the blast furnace, wherein in the injection zone the internal wall comprises local inwards enlargements and the reducing gas injections are performed below said inwards enlargements.