Flameless Burner with Ejector Recirculation for Low NOx
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Solution Overview
Problem
Existing burners suffer from inefficient combustion, high pollutant emissions, and thermal peaks due to excessive comburent use, leading to suboptimal combustion efficiency and increased NOx and CO emissions.
Innovation Solution
A burner employing MILD combustion with a system for directly sucking recycling flue gases using an ejector and comburent injection, combined with a heat exchange system and dual fuel injection systems to form a fuel-recycling flue gas-comburent mixture, which is introduced into the combustion chamber, allowing for reduced comburent excess and improved combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excess comburent is used to ensure complete combustion, then combustion completeness is improved, but combustion efficiency deteriorates and thermal peaks are formed
Solution Approach 1:
The patent applies preliminary action by pre-mixing the fuel with recirculated flue gases before combustion occurs. This pre-mixing process ensures homogeneous distribution of fuel and oxidizer, allowing complete combustion to occur with stoichiometric or near-stoichiometric air-fuel ratios, thereby eliminating the need for excess comburent and avoiding thermal peaks while maintaining combustion completeness.
2Reliability
If excess comburent is used to ensure complete combustion, then combustion completeness is improved, but pollutant emissions increase
Solution Approach 1:
The patent applies preliminary action by pre-mixing the fuel with recirculated flue gases before combustion occurs. This pre-mixing process ensures homogeneous distribution of fuel and oxidizer, allowing complete combustion to occur with stoichiometric or near-stoichiometric air-fuel ratios, thereby eliminating the need for excess comburent and avoiding thermal peaks, thus reducing NOx and CO emissions while maintaining combustion completeness.
3Stability of the object's composition
If flame stabilizer is used to stabilize the flame, then flame stability is improved, but NOx emissions increase
Solution Approach 1:
The patent applies preliminary action by pre-mixing the fuel with recirculated flue gases before combustion occurs. This pre-mixing process ensures homogeneous distribution of fuel and oxidizer, allowing complete combustion to occur with stoichiometric or near-stoichiometric air-fuel ratios, thereby eliminating the need for excess comburent and avoiding thermal peaks, thus reducing NOx and CO emissions while maintaining combustion completeness.
4Stability of the object's composition
If recirculating gases are mixed with fuel jet inside the nozzle, then flame stabilization is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing the fuel with recirculated flue gases before combustion occurs. This pre-mixing process ensures homogeneous distribution of fuel and oxidizer, allowing complete combustion to occur with stoichiometric or near-stoichiometric air-fuel ratios, thereby eliminating the need for excess comburent and avoiding thermal peaks, thus reducing NOx and CO emissions while maintaining combustion completeness.
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 achieves high-efficiency combustion with significantly lower NOx and CO emissions, approaching stoichiometric combustion balance and uniform temperature distribution, reducing pollutant output and eliminating thermal peaks.
Implementation Method 1
The difference of static pressure existing between the combustion chamber and the fluid flowing at a high speed in the nozzle is used
Implementation Method 2
a system for sucking the recycling flue gases directly from a combustion chamber by means of an ejector
Implementation Method 3
a heat exchange system suitable for heat exchange between the recycling flue gases and the comburent
Implementation Method 4
The combustion in burners generally takes place by a flame
Implementation Method 5
a combustion reaction balance approaching the stoichiometric
Data Source
Figure 0
Figure 1
Figure 1a
AI summary
A burner operating with flameless combustion, comprising a system for sucking the recycling flue gases directly from the combustion chamber by means of an ejector (1) fed with the comburent, a heat exchange system positioned between the recycling flue gases and the comburent, a system for injecting the fuel directly into the recycling flue gases, the latter comprising or not comprising the comburent with formation of a mixture of fuel-recycling flue gases-comburent in the zone around the outlet of the comburent ejector and following introduction of the mixture into the combustion chamber.