Solid Fuel Burner With Counter-Swirl Vanes For NOx Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid fuel burners face challenges in maintaining stable combustion and reducing NOx emissions at low fuel concentrations, with existing technologies either dispersing fuel too widely or requiring complex and costly swirl adjustments that increase burner size and installation complexity.
Innovation Solution
A solid fuel burner design featuring a first swirler and a second swirler with reverse swirl vanes, positioned away from the inner wall, to concentrate fuel near the flame stabilizer and reduce swirl strength, enhancing ignitability and stability while preventing fuel scattering and NOx emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single swirler is used to disperse mixed fluid in the furnace, then ignitability and flame stability are improved, but NOx emissions increase due to excessive mixing with combustion air
Solution Approach 1:
The single swirler is divided into two separate swirlers (first swirler and second swirler) positioned at different locations along the fuel nozzle. The first swirler creates initial swirl and concentration, while the second swirler provides additional swirl control near the outlet, allowing staged dispersion that maintains flame stability while controlling mixing with combustion air to reduce NOx emissions
Solution Approach 2:
Different swirl intensities are applied at different locations: the first swirler creates strong swirl for fuel concentration and ignition stability, while the second swirler provides milder swirl control near the outlet to prevent excessive mixing with combustion air, achieving local optimization of both flame stability and NOx reduction
2Reliability
If swirl vanes are installed near the inner wall to concentrate fuel, then ignitability improves, but burner size and installation complexity increase
Solution Approach 1:
The swirl vanes are positioned away from the inner wall (not in contact with it), providing partial swirl action that is sufficient for fuel concentration and ignition improvement, while avoiding the excessive complexity and installation difficulty that would result from wall-mounted vane systems
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 improves flame stability and reduces NOx emissions at low fuel concentrations, simplifies installation, and maintains swirl strength without increasing burner size, ensuring efficient and cost-effective operation.
Implementation Method 1
a first swirler (6) which is provided in the straight tube section (2), and includes a plurality of vanes (6a) installed in the circumferential direction to apply a swirl to the mixed fluid
Implementation Method 2
a second swirler (7) which is provided downstream in a flow direction of the mixed fluid of the first swirler (6) in the straight tube section (2), includes a plurality of vanes (7a) disposed in the circumferential direction, and is installed in a direction reverse to a direction in which vanes (6a) of the first swirler (6) are installed
Data Source
Figure 1
Figure 2(A)~2(D)
Figure 3(A)~3(B)
AI summary
This solid fuel burner (1) is provided with: a nozzle (9) that is provided around the central axis of the burner, that includes a straight tube section (2) having an opening opposed to a furnace (13), and a curved tube section (5) continuous with the straight tube section (2), and that sprays out, from the opening to the furnace (13), a fluid mixture which is of a solid fuel and carrier gas of the solid fuel and which is flowing in the curved tube section (5); a first swirler (6) that gives the fluid mixture a swirl at the burner central axis side of the straight tube section (2); and a second swirler (7) that gives, at the burner central axis side downstream of the first swirler (6), the fluid mixture a swirl opposite to that given by the first swirler (6). The fluid mixture flowing from the curved tube section (5) is moved radially from the central axis by the first swirler (6), and is given a counter-swirl by the second swirler (7) to reduce swirl intensity.