Cylindrical Heating Unit Double-Wall Design for Exhaust Gas Processing
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Solution Overview
Problem
The existing cylindrical heating units in exhaust gas processing devices face issues with high thermal capacity, poor heat transfer efficiency, and increased risk of electric heater disconnection due to surface oxidation and reduced insulation properties of ceramic or refractory materials, leading to shortened heater life and safety concerns.
Innovation Solution
A cylindrical heating unit design featuring a double-walled structure with metal inner and outer cylinders, surrounded by insulators with holding members that provide point contact or line contact to reduce electrical leakage and support the electric heaters, and using materials with higher electric resistance to minimize heat reflection and oxidation, thereby enhancing heat transfer efficiency and preventing disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic powder or refractory material is filled in the double pipe for insulation, then insulation performance is improved, but heat transfer efficiency deteriorates and thermal capacity increases
Solution Approach 1:
The patent removes the ceramic powder or refractory material filling from the double pipe structure, extracting the harmful thermal insulation barrier while maintaining the protective function of the metal cylinders. This extraction resolves the contradiction by eliminating the material that caused poor heat transfer efficiency and excessive thermal capacity.
Solution Approach 2:
The patent employs a composite structure using metal inner and outer cylinders instead of traditional ceramic/refractory material filling. The metal composite structure provides both mechanical strength and superior thermal conductivity, resolving the contradiction between insulation performance and heat transfer efficiency by using materials with appropriate thermal properties for each functional requirement.
2Temperature
If high temperature (close to 1400°C) is applied to generate required temperatures on pipe walls, then decomposition temperature is achieved, but surface oxidation increases and heater life decreases
Solution Approach 1:
The patent introduces an inert gas atmosphere as an intermediary between the electric heater and the oxidizing environment. This intermediary protective atmosphere prevents direct contact between oxygen and the heater surface, eliminating surface oxidation while allowing the heater to operate at the required decomposition temperatures, thus resolving the contradiction between achieving decomposition temperature and extending heater life.
Solution Approach 2:
The patent creates an inert atmosphere within the reaction chamber to prevent oxidation of the electric heater and metal components. By maintaining an oxygen-free or low-oxygen environment, the heater can operate at high temperatures necessary for decomposition without suffering from surface oxidation, thereby resolving the contradiction between temperature requirement and heater durability.
3Adaptability or versatility
If flame burning method is used for wide application field, then decomposition capability is improved, but safety issues increase due to combustion failure risk
Solution Approach 1:
The patent replaces the flame burning mechanical/chemical system with an electrothermal system using electric heaters. This substitution eliminates the combustion process and associated safety risks while maintaining the ability to achieve high temperatures for decomposition. The electric heater provides precise temperature control without the安全隐患 of flame combustion, resolving the contradiction between decomposition capability and safety.
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 solution results in improved heat transfer efficiency, reduced risk of electric heater disconnection, and extended heater life by maintaining lower heat generation temperatures and preventing short circuits, ensuring safer and more efficient operation.
Implementation Method 1
an electric heater such as a nichrome wire or Kanthal (registered trademark of Sandvik AB) wire, which is a heating resistor
Implementation Method 2
filling the space between the pipe walls of the double pipe with ceramic powder or a refractory material for insulation
Implementation Method 3
the processing-target exhaust gas is heated by the circumference of the cylindrical heating unit at high temperatures (atmospheric temperature: 800 to 1150° C.) to be decomposed
Data Source
AI summary
A cylindrical heating unit of an exhaust gas processing device is installed in a reactor. The cylindrical heating unit is provided with an exhaust gas introduction port provided in an insertion base part and a heated exhaust gas outlet provided at insertion end. The cylindrical heating unit includes a hollow cylinder, insulators, electric heaters, and holding members. The hollow cylinder has a double structure with an inner cylinder and an outer cylinder made of metal. A plurality of the insulators surround the inner cylinder and are provided at intervals from each other in a heater installation space between the inner cylinder and the outer cylinder. Electric heaters are mounted to the insulators. The holding members are attached to one of the inner cylinder and the outer cylinder or both and hold the insulators in the heater installation space.