Supersonic Nozzle Gas Injection Metallurgical Bath

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Solution Overview

Problem

Existing metallurgical processes face issues with the penetration depth and wear on refractory materials when introducing process gases into molten metals, leading to clogging and increased wear on equipment.

Innovation Solution

Accelerating process gases to supersonic speeds using Laval supersonic nozzles with convergent and divergent sections, introducing them below the melt bath surface to increase penetration depth and reduce wear, while creating turbulence and shear forces for effective mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If process gas is introduced below the melt bath surface using subsonic gas jets, then the gas can react directly with the liquid metal or slag, but the penetration depth is limited and clogging occurs at the gas inlet

Engineering Contradiction:
Improvegas introduction capabilityVSAvoidclogging resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the velocity parameter of the process gas from subsonic to supersonic speeds. This parameter change fundamentally alters the gas jet behavior, enabling deep penetration into the molten metal without clogging, while maintaining effective gas-metal reaction capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from conventional subsonic gas injection to supersonic gas injection, representing a dimensional change in the flow regime. This enables the gas jet to overcome surface tension and penetrate deeply into the molten bath without the clogging issues that plague subsonic injection systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of moving object

If process gas is introduced at high pressure to increase penetration depth, then the gas can reach deeper into the molten metal, but wear on refractory material increases

Engineering Contradiction:
Improvepenetration depthVSAvoidrefractory material wear
Core Design Contradiction:
Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the velocity parameter from subsonic to supersonic, which fundamentally alters the gas jet characteristics. Supersonic jets achieve deep penetration through molecular-level interactions and turbulence rather than high-pressure impact, thereby avoiding refractory material wear while maintaining effective penetration depth.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If supersonic gas jet is used to increase penetration depth, then the gas jet penetrates deeper into the molten metal, but the complexity of the injection system increases

Engineering Contradiction:
Improvepenetration depthVSAvoidinjection system complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical high-pressure injection systems with supersonic nozzle-based injection. This substitution achieves deep penetration through gas dynamic effects rather than mechanical pressure, simplifying the overall system while enabling deeper gas jet penetration into the molten metal.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Stability of the object's composition

If process gas is introduced to create stirring effect, then mixing is improved, but gas bubbles may coalesce reducing surface area

Engineering Contradiction:
Improvemixing efficiencyVSAvoidgas bubble surface area
Core Design Contradiction:
Stability of the object's compositionVSArea of moving object

Solution Approach 1:

The patent changes the velocity parameter to supersonic speeds, which creates intense turbulence and shear forces that break up gas bubbles into smaller droplets. This maintains high mixing efficiency while preserving large total gas bubble surface area, preventing the coalescence problem that occurs with conventional injection methods.

Inventive Principle:
Principle #35Parameter changes

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

Enhances the penetration depth of process gases, reduces refractory material wear, prevents clogging, and increases the surface area of gas bubbles for improved gas output and mixing within the molten metal.

Implementation Method 1

Accelerating process gases to supersonic speeds using Laval supersonic nozzles with convergent and divergent sections

Methodology Applied
Scientific EffectLaval nozzle effect: De Laval Nozzle

Implementation Method 2

Accelerating process gases to supersonic speeds using Laval supersonic nozzles

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

creating turbulence and shear forces for effective mixing

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 4

creating turbulence and shear forces for effective mixing

Methodology Applied
Scientific EffectShear stress: Shear Stress

Data Source

PatentEP4251776B1Process for treatment of metal melt and / or slag in metallurgical baths
Publication Date: 2024.11.06 SMS GROUP GMBH
  • EP4251776B1 patent drawingFigure 1
  • EP4251776B1 patent drawingFigure 2
  • EP4251776B1 patent drawingFigure 3

AI summary

The invention relates to a method for treating molten metals (4) and/or slags in metallurgical baths, comprising the introduction of a process gas into a melt bath, wherein the process gas is accelerated to supersonic speed and is introduced below the melt bath surface (5) by means of at least one supersonic nozzle (6) with supersonic speed into the liquid phase of the molten metal (4) and/or into the slag and/or into the region of a phase boundary between molten metal and slag. The invention also relates to a metallurgical plant for treating molten metals.