Variable Swirl Fuel Injection Lance for Blast Furnace
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Solution Overview
Problem
Existing pulverized coal injection lances in blast furnaces face instability in flame maintenance at the lance tip, leading to incomplete combustion of coal, as the swirl ratio is geometry-dependent and cannot be varied, affecting burning efficiency.
Innovation Solution
A fuel injection lance design with multiple gas flow channels, including vertical and helical channels, allows for independently controllable gas flow rates to adjust the swirl ratio, maintaining constant total momentum and enabling variable swirl ratios without changing the lance geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flow swirler is provided between coaxial pipes to impart swirling motion to oxygen, then the burning efficiency is improved and flame is maintained, but the swirl ratio is geometry dependent and cannot be varied
Solution Approach 1:
The invention introduces adjustable flow control mechanisms that allow dynamic variation of the swirl ratio. The system includes adjustable flow control elements that enable operators to modify the relative flow rates of oxygen and pulverized coal, thereby changing the swirl ratio to adapt to different operating conditions while maintaining flame stability.
Solution Approach 2:
The invention enables change in the swirl ratio parameter without changing the physical geometry of the lance. By adjusting flow rates through controllable elements, the system can vary the swirl ratio from low to high conditions, allowing optimization for different furnace geometries and operating conditions.
2Speed
If the spiral angle of the flow swirler is made too deep, then the swirling motion is increased, but the oxygen is directed away from the pulverized coal and burning efficiency decreases
Solution Approach 1:
The system allows dynamic adjustment of the effective spiral angle through flow control. By varying the flow rates of oxygen and coal, the system can optimize the swirl intensity to match different operational requirements, preventing both excessive swirling that directs oxygen away from coal and insufficient swirling that fails to improve burning efficiency.
3Reliability
If the spiral angle of the flow swirler is made too shallow, then the oxygen remains close to the pulverized coal, but the improvement of burning efficiency becomes negligible
Solution Approach 1:
The invention enables continuous adjustment of the swirl ratio parameter to find the optimal balance point. By varying flow rates, the system can achieve sufficient swirl to improve burning efficiency while maintaining adequate oxygen-coal mixing, avoiding the negligible improvement zone of shallow spiral angles.
4Adaptability or versatility
If multiple gas flow channels are provided with independently controllable flow rates, then the swirl ratio can be varied, but the device complexity increases
Solution Approach 1:
The invention divides the gas flow system into multiple independently controllable channels, allowing separate control of oxygen and coal flows. This segmentation enables precise control of the swirl ratio while maintaining a manageable structure that can be integrated into existing lance designs.
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 design ensures stable combustion by varying the swirl ratio, allowing for optimal coal particle distribution and improved burning efficiency across different smelting conditions and furnace geometries.
Implementation Method 1
Helical channels traverse the outer surface between the top surface and the bottom surface in a helical pattern... directing the second gas flow into a helical channel... swirling motion to the gas
Implementation Method 2
Each vertical channel intersects with a corresponding helical channel adjacent the bottom surface at a predetermined angle... combining the first gas flow and the second gas flow... optimal coal particle distribution
Implementation Method 3
pulverized coal burns completely the combustion reaction should begin as close to the lance tip as possible... injecting a solid fuel particulate entrained in a gas flow... stable combustion
Data Source
AI summary
A fuel injection lance for an ore-smelting furnace includes a central conduit, a first conduit and a second conduit. The first and second conduits are concentric with the central conduit. A central conduit is connected to a fuel mixture. The first and second conduits are in flow communication with a gas source. The first and second conduits have gas flowing at independently controllable gas flow rates relative to the other conduit. A swirl portion has a cylindrical body with a hollow interior cylinder, and vertical and helical channels formed within the body portion. Vertical channels traverse the body portion vertically to the outer surface adjacent to the bottom surface. Helical channels traverse the outer surface in a helical pattern. Vertical channels intersect with corresponding helical channels at a predetermined angle selected to provide a desired particle distribution of a fuel injected into the furnace.