Staged Combustion Gas Burner for Low NOx Emissions
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Solution Overview
Problem
Existing gas burners face challenges in reducing thermal NOx emissions due to one-step combustion methods that result in temperature peaks, leading to insufficient NOx emission control.
Innovation Solution
The gas burner design incorporates a radially arranged swirler on the primary head with axial main performance nozzles and radial stabilization nozzles, creating a turbulent swirling effect for improved mixing and combustion stability, along with a secondary combustion stage with surplus air, which reduces NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one-step combustion method is used, then combustion simplicity is maintained, but thermal NOx emissions increase due to temperature peaks
Solution Approach 1:
The combustion process is divided into two distinct stages: primary combustion with limited air supply and secondary combustion with surplus air. This segmentation allows the first stage to complete combustion reactions at controlled temperatures, and the second stage to burn remaining fuel with excess air, preventing temperature peaks that generate thermal NOx while maintaining overall combustion efficiency
Solution Approach 2:
The primary combustion stage performs preliminary combustion of fuel with controlled air supply before the secondary stage. This preliminary action ensures that the majority of fuel is consumed at lower temperatures, and the remaining fuel is burned in the second stage with surplus air, preventing the formation of thermal NOx that would occur in a single high-temperature combustion step
2Object-generated harmful factors
If combustion air flow is increased to reduce temperature peaks, then thermal NOx emissions decrease, but combustion efficiency and productivity may be reduced
Solution Approach 1:
Air supply is segmented into two stages: the first stage provides limited air for preliminary combustion, and the second stage provides surplus air for completing combustion. This segmentation ensures that combustion efficiency is maintained by providing sufficient total air, while thermal NOx emissions are reduced by avoiding high-temperature peaks through controlled air introduction timing
Solution Approach 2:
The first combustion stage performs preliminary burning with controlled air supply, and the second stage completes combustion with surplus air. This preliminary action sequence ensures complete fuel consumption and high combustion efficiency while preventing thermal NOx formation by distributing air supply across two temperature-controlled stages
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 design achieves NOx emissions at a level of about 25 ppm in combustion products, effectively addressing the challenge of thermal NOx reduction.
Implementation Method 1
creating a turbulent swirling effect for improved mixing and combustion stability
Implementation Method 2
Gas burners are designed for combustion of gaseous fuels
Data Source
Figure 1~3
AI summary
A gas burner (1) with a cylindrical casing (3) being open from below for the flow of the combustion air, and having a gas burner output, a central primary head (15), arranged in the axis of the cylindrical casing (3), and having axial main performance nozzles (19), a swirler (13), and radial stabilization nozzles (20) around the circumference of the central primary head (15) provided in front of the swirler (13) in the direction of the gas burner output, and a fuel tube (7, 8, 9, 10, 11, 16, 22) with a gas distributor (16) and a tube portion (11), a reduction piece (12) being arranged on the tube portion (11) leading from the gas distributor (16) to the central primary head (15), and provided with a passing-through opening (17) being smaller than an opening in the tube portion (11), wherein the central primary head (15) is arranged on the reduction piece (12), in front of the central primary head (15), the fuel tube (7, 8, 9, 10, 11, 16, 22) is divided into a plurality of tubes (5) arranged in a circle, and the fuel nozzles (18) of the plurality of tubes (5) are arranged on the gas burner output of the casing (3) and orientated into the gas burner output.