Hot-blast lance thermal insulation design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hot blast lances experience significant temperature losses and mechanical stress when introducing hot blast into steel converters, leading to inefficient energy transfer and reduced scrap usage rates due to thermal cycling and abrasive conditions.
Innovation Solution
A hot blast lance design featuring a thermally insulating inner jacket with a ceramic coating and a water-cooled structure, including an intermediate space for coolant flow, which minimizes heat transfer and protects against abrasive and oxidative loads, while allowing high-temperature operation with reduced mechanical stress through a floating innermost jacket and optimized flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-cooled structure is used to protect the hot blast lance from high temperatures, then the lance is protected from thermal damage, but significant heat energy is extracted from the hot blast, reducing its temperature and detrimental to the energy balance
Solution Approach 1:
The lance is divided into multiple functional zones: a water-cooled outer jacket for structural protection, an uninsulated intermediate section for minimal heat loss, and an insulated innermost section for hot blast delivery. This segmentation allows different parts of the lance to serve different thermal management functions simultaneously.
Solution Approach 2:
Different sections of the lance have different thermal insulation properties: the outer jacket is water-cooled for protection, the intermediate section has reduced insulation for energy efficiency, and the innermost section has minimal or no insulation to deliver hot blast at high temperature. Each section's thermal properties are optimized for its specific function.
2Duration of action of stationary object
If the hot blast lance is cooled intensively with water to protect it from high gas temperatures, then the lance can operate continuously in the reaction vessel, but the hot blast temperature is reduced and energy transfer efficiency decreases
Solution Approach 1:
The lance structure is segmented into a water-cooled outer jacket for durability and continuous operation, and an innermost uninsulated or minimally insulated jacket for maintaining high hot blast temperature. This allows the lance to withstand thermal cycling while delivering hot blast at required temperatures.
Solution Approach 2:
An intermediate section with reduced insulation or different thermal properties is introduced between the water-cooled outer jacket and the innermost hot blast delivery section. This intermediary zone allows gradual thermal transition and minimizes heat loss while protecting the cooled outer structure.
3Loss of energy
If a thermally insulating inner jacket is used to maintain hot blast temperature, then temperature losses are reduced, but the lance becomes more susceptible to mechanical stress and thermal cycling damage
Solution Approach 1:
The lance is segmented into a water-cooled outer jacket that provides mechanical strength and thermal shock resistance, and an innermost section with minimal insulation that maintains hot blast temperature. The segmentation allows each section to optimize for its primary function while the outer jacket protects the inner section from mechanical and thermal stress.
4Reliability
If the inner jacket is made of abrasion-resistant material to withstand abrasive conditions, then the lance durability is improved, but heat transfer efficiency may be reduced and temperature losses increase
Solution Approach 1:
The innermost jacket is provided with a protective coating or lining on the side exposed to hot blast and abrasive conditions, while the outer and intermediate sections maintain their thermal management properties. This localized protection allows the lance to withstand abrasive and oxidative loads without compromising overall heat transfer efficiency.
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 reduces temperature losses and enhances the robustness of the lance, enabling higher scrap rates and efficient heat transfer to the molten pool by maintaining the hot blast at higher temperatures with reduced thermal cycling and mechanical stress.
Implementation Method 1
the inner or innermost jacket consists at least partially of a thermally insulating secondary jacket, or of a thermally insulating jacket, or is coated with a thermally insulating layer
Implementation Method 2
at least one intermediate space or cooling channel through which coolant flows is arranged between the outer and an inner jacket
Implementation Method 3
the inner or innermost jacket consists at least partially of a thermally insulating secondary jacket, or of a thermally insulating jacket, or is coated with a thermally insulating layer
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a hot-blast lance for use in metallurgical processes, such as for example steel production, with which hot air can be blown in above a molten bath of a steel converter, which consists of an outer shell and at least one inner shell, and at least one intermediate space or cooling channel through which coolant flows is arranged between the outer shell and an inner shell. In order to achieve the effect here that a hot-blast lance can be further developed to the extent that hot air can be introduced into a reaction vessel, for example a steel converter, particularly effectively, that is to say with least possible thermal losses, and the lance is adapted better to this operating environment, it is proposed according to the invention that the inner shell (2) or the innermost shell (4) at least partially consists of a thermally insulating further shell (4), or a thermally insulating shell, or is provided with such a shell, or is coated with a thermally insulating layer.