Smelt Cyclone Accretion Control via Dynamic Oxygen Injection
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Solution Overview
Problem
In the HIsarna process, uneven heat flux on the smelt cyclone walls due to accretion formation leads to reduced productivity as metalliferous material is entrained in off-gas, affecting gas flow patterns and metal production.
Innovation Solution
Implementing a method to control accretion formation by adjusting the supply of metalliferous feed material and oxygen-containing gas through tuyeres based on temperature measurements, reducing supply to areas with low heat flux to localize and remove accretions, and increasing oxygen supply to enhance combustion and accretion removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If oxygen-containing gas is injected into the smelt cyclone to generate cyclonic flames for heating and partial melting of metalliferous feed material, then the temperature and smelting efficiency are improved, but accretions form on the cyclone walls causing uneven heat flux and reduced productivity
Solution Approach 1:
The patent implements a feedback control system where temperature sensors monitor the temperature in the cyclone chamber and adjust the oxygen flow rate accordingly. When accretions form and cause temperature deviations, the system automatically adjusts oxygen injection to restore optimal temperature conditions, preventing productivity loss while maintaining high temperatures for efficient smelting
Solution Approach 2:
The patent dynamically changes operational parameters (oxygen flow rate, feed material rate) based on detected accretion conditions. By adjusting these parameters in response to temperature changes caused by accretions, the system maintains optimal smelting conditions while preventing the harmful effects of uneven heat flux and material loss
2Productivity
If feed material is injected at high rates to increase productivity, then output is improved, but accretion formation on cyclone walls increases leading to uneven heat flux and material loss in off-gas
Solution Approach 1:
The system uses temperature monitoring and control to detect accretion formation early. When accretions are detected through temperature deviations, the feedback control reduces feed material injection rate to prevent further accretion growth and material loss, while maintaining sufficient productivity through dynamic adjustment rather than continuous high-rate injection
Solution Approach 2:
The patent employs dynamic adjustment of feed material injection rate based on real-time cyclone conditions. Rather than operating at constant high rates, the system dynamically modulates the injection rate to match actual processing conditions, preventing accretion-related losses while maintaining high average productivity
3Stability of the object's composition
If accretions are allowed to form on cyclone walls, then heat flux distribution becomes uneven causing gas flow pattern changes, but removing accretions requires maintenance shutdowns reducing operational continuity
Solution Approach 1:
The temperature monitoring and control system provides continuous feedback on heat flux distribution through temperature measurements. When uneven heat flux is detected indicating accretion formation, the system adjusts oxygen and feed rates to prevent further accretion growth, maintaining stable heat flux distribution and operational continuity without shutdowns
Solution Approach 2:
The system takes preliminary action by detecting and responding to early signs of accretion formation through temperature monitoring. By adjusting operational parameters before significant accretions form, the system prevents the need for maintenance shutdowns and maintains both heat flux stability and operational continuity
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 maintains uniform heat flux across the cyclone walls, reduces accretion impact, and prevents metalliferous material from leaving with off-gas, thereby enhancing productivity and operational stability without requiring additional maintenance.
Implementation Method 1
a cooling system with fluid-cooled panels is provided in the wall of the smelt cyclone
Implementation Method 2
a cooling system with fluid-cooled panels is provided in the wall of the smelt cyclone
Implementation Method 3
Oxygen-containing gas (typically technical-grade oxygen) is injected into the smelt cyclone via tuyeres that are arranged in such a way as to generate a cyclonic swirl pattern about a central axis of the chamber of the smelt cyclone. This injection of oxygen-containing gas leads to further combustion of smelting vessel gases, resulting in very hot (cyclonic) flames.
Implementation Method 4
This injection of oxygen-containing gas leads to further combustion of smelting vessel gases
Implementation Method 5
The vortex or whirling flow in the cyclone promotes mixing of the injected oxygen and the reducing process gas and also heat exchange with the metalliferous material. As a result of the swirl motion, particles of metalliferous material and molten metalliferous material are separated from the gas and collect on the wall of the cyclone wall
Implementation Method 6
As a result of the swirl motion, particles of metalliferous material and molten metalliferous material are separated from the gas and collect on the wall of the cyclone wall
Implementation Method 7
wherein the method comprises controlling the supply of feed material and/or oxygen containing gas dependent on temperatures measured in the fluid-cooled panels
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
The invention relates to method of operating a smelt cyclone, wherein the supply of feed material and/or the supply of oxygen containing gas through an array of tuyeres into the smelt cyclone is controlled in order to control accretions of metalliferous feed material at the inside of the smelt cyclone.