Fluid Cooled Lance with Constriction for Wear Reduction
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Solution Overview
Problem
Top submerged injecting lances in molten bath pyrometallurgical operations face significant wear and burn-back issues due to high temperatures, leading to frequent interruptions and increased operational costs, as existing cooling methods are inadequate in maintaining the structural integrity and longevity of the lances.
Innovation Solution
A fluid-cooled top submerged injecting lance design featuring three concentric pipes with a replaceable tip assembly and a shroud, utilizing a constriction in the coolant fluid flow to enhance heat energy extraction, allowing for efficient cooling and reducing wear and burn-back through increased surface contact and velocity of the coolant fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling methods are used for top submerged injecting lances, then the lance structure is maintained, but wear and burn-back occur rapidly due to high temperatures
Solution Approach 1:
The patent implements a multi-layer concentric pipe structure where multiple pipes are nested within each other. The innermost pipe carries process gas, intermediate pipes provide cooling water flow paths, and the outermost pipe forms the lance exterior. This nesting allows coolant to flow through annular spaces between concentric pipes, creating efficient heat removal paths while maintaining structural integrity against thermal damage.
Solution Approach 2:
The patent employs hydraulic cooling by circulating water through the intermediate pipes and annular spaces of the concentric structure. The cooling water absorbs heat from the lance surfaces exposed to high-temperature molten bath, preventing excessive temperature rise and associated wear or burn-back of the lance materials.
2Productivity
If the lance is submerged deeper in the molten bath, then injection efficiency improves, but heat exposure and wear increase
Solution Approach 1:
The concentric pipe configuration enables the lance to extend deeper into the molten bath for improved injection efficiency while incorporating multiple cooling water flow paths through intermediate pipes. The nested structure provides redundant cooling channels that remove heat more effectively, allowing the lance tip to withstand prolonged exposure to high temperatures and extend operational life.
Solution Approach 2:
The cooling system is designed to preemptively remove heat from the lance surfaces before thermal damage can occur. The intermediate pipes carry cooling water that contacts the hottest surfaces of the lance, preventing burn-back and wear even when the lance is deeply submerged for optimal injection performance.
3Loss of energy
If cooling water flow rate is increased, then heat removal efficiency improves, but energy consumption and operational complexity increase
Solution Approach 1:
The concentric pipe design integrates multiple cooling water flow paths within the lance structure itself, utilizing annular spaces between nested pipes. This allows cooling water to be distributed along different sections of the lance simultaneously, maximizing heat removal efficiency without requiring external cooling equipment or complex control systems.
Solution Approach 2:
The lance structure serves its own cooling needs through the integrated concentric pipe system. The intermediate pipes and annular spaces form self-contained cooling channels that require only a water supply, eliminating the need for separate cooling apparatus and reducing operational complexity while maintaining effective heat removal.
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
The design significantly extends the operational life of the lance by minimizing wear and burn-back, reducing downtime, and allowing for more efficient heat energy extraction, thereby reducing the frequency of lance replacements and associated costs.
Implementation Method 1
coolant fluid is circulated through the shell of the lance... flow between the innermost and intermediate lance pipes of the shell and then back along the lance
Implementation Method 2
enhance heat energy extraction... increased surface contact and velocity of the coolant fluid
Implementation Method 3
The intermediate pipe may define a peripheral bead which has a radially curved, convex surface... the end wall may be of a complementary concave form... provide a constriction in the coolant fluid flow path
Data Source
AI summary
A TSL lance has an outer shell of three substantially concentric lance pipes, at least one further lance pipe concentrically within the shell, and an annular end wall at an outlet end of the lance which joins ends of outermost and innermost lance pipes of the shell at an outlet end of the lance and is spaced from an outlet end of the intermediate lance pipe of the shell. Coolant fluid is able to be circulated through the shell, by flow to and away from the outlet end. The spacing between the end wall and the outlet end of the intermediate pipe provides a constriction to the flow of coolant fluid to increase coolant fluid flow velocity therebetween. The further lance pipe defines a central bore and is spaced from the innermost lance pipe of the shell to define an annular passage, whereby materials passing along the bore and the passage mix adjacent to the outlet end of the lance. The end wall and an adjacent minor part of the length of the shell comprise a replaceable lance tip assembly.