Cylindrical Burner With Flue Gas Recirculation for Low-Noise Operation
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Solution Overview
Problem
Existing fire tube burners face issues with tall exhaust stacks causing noise pollution, high installation costs, and increased NOx emissions, and forced air blower systems are expensive and noisy, requiring further emission reductions.
Innovation Solution
A cylindrical burner apparatus that induces combustion air and recycled flue gas flow without natural draft or blowers, using angled fuel discharge ports to create a swirling flame and flue gas recirculation, reducing NOx emissions and noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a natural draft system with a tall exhaust stack is used, then combustion air flow is provided, but noise pollution and combustion rumble increase severely
Solution Approach 1:
The invention extracts and eliminates the tall exhaust stack from the system by using a short stack combined with flue gas recirculation. The recirculation system draws flue gases back into the combustion chamber, providing the necessary draft without requiring a tall stack, thereby eliminating the source of combustion rumble and noise pollution while maintaining proper combustion air flow.
Solution Approach 2:
The invention introduces flue gas recirculation as an intermediary mechanism between the exhaust and combustion chambers. This recirculated flue gas acts as a mediator that provides the draft effect normally achieved by tall stacks, but through a controlled recirculation path that prevents the harmful noise and rumble associated with natural draft systems.
2Productivity
If a forced air blower system is used, then combustion air flow and flame length are improved, but system cost and operational expense increase
Solution Approach 1:
The invention makes the combustion system self-service by using the combustion process itself to generate the necessary air flow. Flue gases from combustion are recirculated back through the combustion chamber, creating a natural draft effect that eliminates the need for external blowers or fans, thereby reducing system cost and operational expenses while maintaining adequate combustion air flow capacity.
Solution Approach 2:
The invention replaces the mechanical blower system with a thermal-fluid mechanism. Instead of using mechanical force to move air through the system, the recirculation of hot flue gases creates a thermal draft that naturally drives combustion air flow, eliminating the need for mechanical components and associated costs.
3Productivity
If a forced air blower system is used, then flame length and capacity are increased, but NOx emissions are not sufficiently reduced
Solution Approach 1:
The invention changes the chemical composition parameters of the combustion atmosphere by recirculating flue gases rich in CO2 and H2O back into the combustion chamber. This dilutes the oxygen concentration and lowers the peak combustion temperature, which significantly reduces NOx formation while maintaining adequate flame length and combustion capacity through the continued recirculation process.
Solution Approach 2:
The recirculated flue gas acts as an intermediary substance that modifies the combustion environment. By introducing this intermediate gas stream, the system achieves lower combustion temperatures and reduced NOx emissions while still maintaining the flame characteristics needed for productive operation.
4Ease of operation
If a tall exhaust stack is used, then natural draft is provided, but equipment installation cost and space requirements increase
Solution Approach 1:
The invention extracts the draft-generating function from the tall stack structure. By using flue gas recirculation to create the necessary pressure differential for natural draft, the system eliminates the need for a tall stack while maintaining the same draft effect, thereby reducing equipment installation cost and space requirements.
Solution Approach 2:
The invention shifts the draft generation from a vertical dimension (tall stack height) to a recirculation dimension. Instead of relying on vertical height to create the draft effect, the system uses a recirculation loop that creates the necessary pressure differential through the thermal and compositional properties of the recirculated flue gases, effectively solving the problem in a different dimensional approach.
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 apparatus achieves low NOx emissions below 30 ppm, minimal noise levels, and eliminates the need for tall stacks and blowers, providing a cost-effective and quieter operation.
Implementation Method 1
discharging jets of a gas fuel from a plurality of fuel discharge ports positioned in the initial tube pass forwardly of the rearward end, and inducing a flow of combustion air into the rearward end of the initial tube pass
Implementation Method 2
creating a swirling flame and flue gas recirculation
Implementation Method 3
discharging jets of a gas fuel... inducing a flow of combustion air... combustion process
Implementation Method 4
As hot combustion gases flow through the fire tubes, they heat the water that surrounds the tubes
Implementation Method 5
inducing a flow of recycled flue gas from a subsequent tube pass into the initial tube pass, via a flue gas recirculation duct... providing Flue Gas Recirculation (FGR) to the combustion system
Data Source
AI summary
A cylindrical burner apparatus and method which produce low noise levels and are not dependent upon a blower, or natural draft, for providing combustion air flow. A flow of combustion air is induced into a rearward end of a burner tube and a swirling flame is produced in the tube by discharging a gas fuel from a plurality of discharge ports located in the tube.