Burner Oxygen-Concentration Control for Uniform Ladle Preheating

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Solution Overview

Problem

Existing methods for preheating ladles in pig iron or steel manufacturing plants are inefficient, leading to prolonged process times and potential refractory brick damage due to rapid temperature changes, while also generating significant amounts of carbon dioxide and nitrogen oxides.

Innovation Solution

A method and device that gradually increase the oxygen concentration in the combustion supporting gas supplied to a burner, using a controlled flow rate and phase difference to uniformly heat the ladle in a shorter time, reducing carbon dioxide and nitrogen oxide emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rapid heating is applied to bring the ladle to predetermined temperature quickly, then the preheating time is reduced and production efficiency is improved, but the refractory bricks may be broken due to partial thermal expansion

Engineering Contradiction:
Improvepreheating timeVSAvoidrefractory brick integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies periodic oscillation to the combustion state by periodically changing the oxygen concentration in the combustion supporting gas. This creates cyclic heating and cooling periods that prevent excessive temperature gradients in the refractory bricks, avoiding thermal shock and brick breakage while maintaining efficient preheating overall

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the oxygen concentration parameter in the combustion supporting gas from constant to dynamically varying. By controlling the oxygen concentration to oscillate periodically, the flame temperature and heating rate are modulated, allowing rapid preheating without subjecting refractory bricks to sustained extreme thermal stress

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional combustion is used with air as combustion supporting gas, then the process is simple and easy to operate, but significant amounts of carbon dioxide and nitrogen oxides are generated

Engineering Contradiction:
Improvecombustion process simplicityVSAvoidcarbon dioxide and nitrogen oxide emissions
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent changes the composition parameter of the combustion supporting gas by gradually increasing oxygen concentration from 21% (air) to higher levels. This parameter change reduces the volume of combustion gas produced and lowers nitrogen oxide formation, while the periodic oscillation prevents complete combustion conditions that would maximize CO2 production

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite combustion supporting gas system that combines air with controlled oxygen supplementation. This composite gas mixture allows optimization of combustion efficiency while reducing harmful emissions, balancing simplicity of operation with environmental considerations

Inventive Principle:
Principle #40Composite materials

3Reliability

If slow heating is applied to prevent refractory brick breakage, then the refractory bricks are heated uniformly without damage, but the preheating process time is prolonged and production efficiency is reduced

Engineering Contradiction:
Improverefractory brick integrityVSAvoidpreheating process time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements periodic oscillation of the combustion state where heating periods are alternated with periods of reduced heating intensity. This periodic action allows heat to penetrate uniformly into the refractory structure during heating phases while the cooling phases prevent excessive temperature gradients, achieving both uniform heating and reasonable process time

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent transitions from static constant combustion to dynamic oscillating combustion. The combustion state is continuously adjusted through periodic changes in oxygen concentration, creating a dynamic heating process that adapts to the thermal state of the ladle and refractory bricks, optimizing both uniformity and time efficiency

Inventive Principle:
Principle #15Dynamics

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 method and device enable efficient, environmentally friendly preheating of ladles by uniformly heating them in a shorter time, minimizing refractory brick damage and emissions, thus enhancing production efficiency.

Implementation Method 1

a flame which is produced by supplying a fuel fluid and a combustion supporting gas to a burner as a heat source

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

heat transfer efficiency from the flame to the object to be heated

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

heat transfer efficiency from the flame to the object to be heated

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3598002B1Method and device for heating to-be-heated object
Publication Date: 2025.10.22 NIPPON SANSO CORP
  • EP3598002B1 patent drawingFigure 1
  • EP3598002B1 patent drawingFigure 2
  • EP3598002B1 patent drawingFigure 3

AI summary

One object of the present invention is to provide a method and a device for heating an object to be heated which can uniformly heat the object to be heated in a shorter time than in the prior art, the amount of carbon dioxide, nitrogen oxides (NOx), and the like generated can be significantly reduced, and the object to be heated can be dried and heated efficiently and in an environmentally friendly manner, and the present invention provides a method for heating an object to be heated by a flame (2) which is produced by supplying a fuel fluid (M1, M2) and a combustion supporting gas (G3) to a burner (3) as a heat source, wherein a temperature rising rate is increased by gradually increasing an oxygen concentration in the combustion supporting gas (G3) supplied to the burner (3) and a device for heating an object to be heated including a burner (3) for heating the object to be heated, a flow rate control unit (4) for controlling a flow rate of a fuel fluid (M1, M2) and a combustion supporting gas (G3), and a calculation unit (5) for transmitting combustion information of the burner (3) to the flow rate control unit (4), and the flow rate control unit (4) increases a temperature rising rate of the object to be heated by increasing the oxygen concentration in the combustion supporting gas (G3) supplied to the burner (3).