Steelmaking Concentric-Tube Oxygen Lance for Post-Combustion Control
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Solution Overview
Problem
Existing steelmaking technologies face challenges in achieving controlled post-combustion with independent oxygen flow management without requiring significant installation modifications or high investment costs.
Innovation Solution
A lance design with concentric tubes for primary and secondary oxygen flows, integrated cooling water channels, and a distributor for independent oxygen control, allowing efficient post-combustion with reduced investment costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a double flow lance with independent oxygen supply is used, then post-combustion control and productivity are improved, but investment cost and device complexity increase significantly
Solution Approach 1:
The patent implements a nested tube structure where the primary oxygen tube is positioned inside the secondary oxygen tube. The primary oxygen ejection means are located in the lower part of the inner tube, while secondary oxygen ejection means are positioned in the upper part of the annular space between the two tubes. This nesting arrangement enables independent control of primary and secondary oxygen flows while maintaining a compact lance structure that does not require complete installation replacement.
Solution Approach 2:
The lance is divided into distinct functional segments: the primary oxygen supply system with ejection means in the lower part, and the secondary oxygen supply system with ejection means in the upper part. Each segment has its own control mechanism, allowing independent adjustment of oxygen flows. The distributor assembly separates the two oxygen streams while enabling their coordinated operation, thus resolving the contradiction between independent flow control and structural complexity.
2Ease of manufacture
If a single oxygen flow supply is used, then investment cost is reduced, but post-combustion control capability deteriorates
Solution Approach 1:
The lance design integrates multiple functions into a single device: it can operate in single oxygen flow mode (using only the primary oxygen supply) for cost-effective installations, and switch to double flow mode (utilizing both primary and secondary oxygen supplies) when enhanced post-combustion control is required. The distributor assembly and sealing means enable flexible operation modes, making the lance universally applicable to different operational requirements without requiring complete system replacement.
3Productivity
If secondary oxygen ejection means are positioned too close to primary oxygen ejection means, then post-combustion efficiency improves, but water circulation and cooling effectiveness deteriorate
Solution Approach 1:
The patent positions the secondary oxygen ejection means in the vertical dimension above the primary oxygen ejection means, rather than placing them side-by-side in the same horizontal plane. The secondary oxygen is introduced through the annular space between the primary and secondary tubes at a higher elevation, allowing the cooling water to flow downward through the annular gap without interference from the oxygen jets. This vertical separation maintains post-combustion efficiency while preserving effective water circulation and cooling.
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 efficient post-combustion with reduced investment costs by maintaining existing installation compatibility and minimizing water pressure losses, while enhancing oxygen flow control and energy release for scrap melting.
Implementation Method 1
a main tube for the supply of a primary flux of oxygen, a second tube surrounding the main tube to form a first annular gap for the circulation of cooling water within the lance, a third tube surrounding the second tube to form a second annular gap for the supply of a secondary flux of oxygen
Implementation Method 2
a second tube surrounding the main tube to form a first annular gap for the circulation of cooling water within the lance
Implementation Method 3
the primary oxygen ejection means are designed so as to eject the primary flux of oxygen with an ejection angle α with the central axis Z of the lance from 10 to 20°
Implementation Method 4
the unburned CO moving upward meets additional O2 provided by this secondary flow and is then combusted into CO2. The reaction is defined by the commonly known equation: CO + 1⁄2O2 = CO2
Implementation Method 5
The transformation of CO to CO2 is known as post-combustion... the more CO2 is formed, the more heat is created and may be transferred to bath so as to provide energy for additional scrap melting
Data Source
Figure 1
Figure 2
AI summary
A lance (1) for blowing oxygen onto a bath of molten steel comprising a tip (15) provided with first oxygen ejection means (16) and a distributor (17) provided with second ejection means (18).