Boiler Cooling Device for Exhaust Gas Recirculation
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Solution Overview
Problem
Current boiler systems face challenges in reducing NOx emissions efficiently and energy-safely during fuel combustion, particularly due to limitations in exhaust gas recirculation efficiency within the combustion chamber.
Innovation Solution
The boiler system incorporates a cooling device with protruding cooling elements that absorb and dissipate heat from recirculated exhaust gas, reducing its temperature and increasing the mass flow of recirculated exhaust gas, which is then reintroduced into the combustion chamber, thereby enhancing internal exhaust gas recirculation and mixing with combustion air to lower oxygen partial pressure and reduce combustion temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If internal exhaust gas recirculation is increased to reduce NOx emissions, then pollutant emissions are reduced, but the temperature of recirculated exhaust gas increases reducing recirculation efficiency
Solution Approach 1:
A cooling device is introduced as an intermediary component between the exhaust gas recirculation system and the combustion chamber. This cooling device includes cooling elements that extend into the combustion chamber and are surrounded by recirculated exhaust gas, allowing heat transfer from the exhaust gas to the cooling elements. This intermediary cooling mechanism enables the system to maintain high exhaust gas recirculation rates for NOx reduction while controlling the temperature of recirculated gas to preserve recirculation efficiency.
2Use of energy by moving object
If cooling elements are positioned close to the burner for effective cooling, then heat absorption efficiency improves, but the structural complexity of the burner basket increases
Solution Approach 1:
The cooling elements are integrated into the existing burner basket structure, allowing the burner basket to serve dual functions: supporting the burner assembly and providing pathways for cooling elements. The cooling elements extend through the burner basket walls, utilizing the existing structural framework rather than requiring separate mounting arrangements. This multi-functional integration reduces the overall structural complexity despite the addition of cooling functionality.
Solution Approach 2:
The cooling elements are strategically positioned at specific locations within the burner basket where recirculated exhaust gas flows, creating localized cooling zones. The cooling elements extend into the combustion chamber at positions optimized for heat absorption from the recirculated exhaust gas, while the burner basket structure maintains its essential integrity. This localized approach concentrates cooling effectiveness at critical areas without requiring comprehensive structural modifications throughout the entire burner assembly.
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
This approach effectively increases the exhaust gas mass recirculation, reduces NOx emissions by 10-15%, and improves the temperature profile within the combustion zone, minimizing 'hot spots and thermal ballast effects, while maintaining the same fuel properties and burner configurations.
Implementation Method 1
a cooling device with which heat from the recirculated exhaust gas can be absorbed and dissipated
Implementation Method 2
heat from the recirculated exhaust gas can be absorbed and dissipated
Implementation Method 3
enhancing internal exhaust gas recirculation and mixing with combustion air to lower oxygen partial pressure
Implementation Method 4
a cooling device with which heat from the recirculated exhaust gas can be absorbed and dissipated
Data Source
Figure 1~4
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Figure 8~11
AI summary
The boiler system serves to generate heat by burning at least one fuel and comprises a burner basket (20) for receiving a burner (30) with which a flame (40) can be generated, wherein the boiler system is configured to recirculate exhaust gas (50) generated during combustion back into the flame (40). A cooling device (60) is arranged in the exhaust gas recirculation area (51) with which heat from the recirculated exhaust gas (50) can be absorbed and dissipated, wherein the cooling device (60) has at least one cooling element in which a cooling medium (61) can be received or absorbed, and wherein the cooling element can be exposed to recirculated exhaust gas (50).