Burner Head Swirler for Flame Stability and NOx Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing single-stage combustion methods face challenges in stabilizing flames at a distance from the burner head and minimizing nitrogen oxide formation, particularly in single-fuel and dual-fuel burners, due to inadequate fuel and combustion air mixing and the destabilizing effect of exhaust gas recirculation.
Innovation Solution
A combustor head design featuring a swirler for swirled combustion air and multiple fuel nozzles to create separate mixing zones within the combustor tube, where swirled combustion air and unburned fuel are mixed, and recirculated exhaust gases are reintroduced to form a stable combustion zone outside the burner head, optimizing fuel and air mixing and reducing nitrogen oxide formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas is recirculated to reduce nitrogen oxide formation, then nitrogen oxide emissions are reduced, but flame stability deteriorates
Solution Approach 1:
The combustion process is divided into two distinct zones: a first combustion zone close to the burner head where fuel mixes with primary combustion air, and a second combustion zone downstream where recirculated exhaust gas is introduced. This segmentation allows flame stabilization in the first zone while enabling exhaust gas recirculation in the second zone to reduce nitrogen oxide emissions.
Solution Approach 2:
A recirculation channel is introduced as an intermediary structure that transports exhaust gas from the second combustion zone back to the mixing zone. This mediator enables the beneficial effect of exhaust gas recirculation (reduced nitrogen oxide formation) while isolating its detrimental effect (flame destabilization) from the flame stabilization region.
2Device complexity
If single-stage combustion is used to simplify the combustion process, then device complexity is reduced, but flame stabilization at a distance from the burner head becomes difficult
Solution Approach 1:
The single-stage combustion system is segmented into functional zones: a mixing zone with a swirler for flame stabilization, a first combustion zone, and a second combustion zone with exhaust gas recirculation. This segmentation enables flame stabilization at a distance while maintaining a relatively simple overall structure compared to dual-stage combustion systems.
3Productivity
If fuel and combustion air are mixed more intensively to optimize combustion, then combustion efficiency is improved, but mixing complexity increases
Solution Approach 1:
A swirler with curved blades is used to generate rotational flow and enhance mixing between fuel and combustion air. The curved geometry of the swirler blades creates intense turbulence and mixing in the mixing zone, optimizing combustion efficiency without requiring complex mechanical mixing devices.
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 enhances flame stability and reduces nitrogen oxide emissions by ensuring intensive mixing of fuel and air, allowing for efficient combustion while minimizing pollutant formation, and eliminates the need for a continuous pilot flame within the burner head.
Implementation Method 1
a swirler for supplying swirled combustion air into a first combustion-free mixing zone downstream of the swirler within the combustor tube
Implementation Method 2
baffles (32) extending from the disc (28) in a downstream direction and inclined inwards towards the longitudinal axis (24) of the burner head (2)
Implementation Method 3
single-stage combustion of fuel in a combustion zone spaced downstream of the combustor head
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The head (2) has a twisting device (38) supplying twisted combustion air into a combustion-free mixing chamber (52) downstream to the twisting device within a burner pipe (22). Two fuel nozzles (8, 16) arranged downstream of the twisting device within the pipe supply unburnt fuel into the chamber to mix the unburnt fuel with the twisted combustion air. The twisting device has an area (48) downstream to an area (44) that comprises twisting elements (46) for twisting combustion air, where the area (48) guides the twisted combustion air separated from the combustion air into the area (44). An independent claim is also included for a method for single-stage combustion of fuel in a combustion chamber.