Dual-Port Low NOx Burner for Water Heater Emissions Control
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Solution Overview
Problem
Conventional water heaters produce excessive nitrogen oxides (NOx) during combustion due to high flame temperatures, which is not effectively mitigated by existing technologies.
Innovation Solution
A low NOx burner system comprising an inner and outer burner with a removable inlet tube that supplies fuel/air mixtures at different rates to the burners, reducing flame temperature and NOx emissions by using a lean-rich dual combustion approach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional burner is used to provide high heating output, then the heating capacity is sufficient, but nitrogen oxides (NOx) emissions increase due to high flame temperatures
Solution Approach 1:
The burner is divided into multiple separate burner ports (e.g., primary burners and secondary burners) that operate independently with different fuel/air mixture ratios. This segmentation allows each port to contribute differently to the overall combustion process, enabling high total heating output while maintaining lower flame temperatures at individual ports, thereby reducing NOx emissions.
Solution Approach 2:
Different regions of the burner are designed with distinct local characteristics - some burner ports receive fuel-rich mixtures while others receive fuel-lean mixtures. This local differentiation in combustion characteristics allows the system to achieve both high overall power output and reduced peak flame temperatures that generate NOx, as each local region operates under optimized conditions for its specific function.
2Object-generated harmful factors
If the fuel/air mixture ratio is adjusted to reduce flame temperature and NOx emissions, then NOx emissions decrease, but combustion efficiency and heating output may be reduced
Solution Approach 1:
The burner combines multiple combustion streams with different fuel/air ratios into a single integrated system. By merging the outputs of primary burners (operating at one mixture ratio) and secondary burners (operating at a different mixture ratio), the system achieves both reduced NOx emissions from individual low-temperature zones and maintained high heating output through the cumulative effect of all burners operating simultaneously.
Solution Approach 2:
The combustion process uses a composite approach by combining fuel-rich and fuel-lean combustion zones within the same burner assembly. This composite combustion strategy allows the system to leverage the benefits of both mixture types - the fuel-rich zones suppress NOx formation while the fuel-lean zones ensure complete combustion - achieving both emission reduction and high heating output.
3Adaptability or versatility
If multiple burner configurations are manufactured to meet different emission standards, then compliance with various regulations is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The burner incorporates adjustable components such as removable inlet tubes with different opening arrangements, adjustable fuel/air mixture controls, and reconfigurable burner port configurations. These dynamic elements allow a single burner body to be adjusted to meet different emission standards and performance requirements without requiring multiple fixed designs, thereby reducing manufacturing complexity while maintaining compliance flexibility.
Solution Approach 2:
The burner design incorporates universal features that enable it to function across multiple application scenarios and meet various emission standards. By integrating multiple burner types (primary and secondary) with adjustable parameters into a single platform, the design achieves multi-functionality where one burner assembly can serve different market segments and regulatory requirements, eliminating the need for separate dedicated burners for each standard.
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 system effectively reduces NOx emissions and allows for adjustable combustion characteristics, enhancing manufacturing flexibility and reducing emissions below regulatory limits, such as California's 40 nanograms per joule of heat output for residential water heaters.
Implementation Method 1
Nitrogen oxides (NOx) are formed during combustion. NOx is typically generated by high temperature flames.
Implementation Method 2
The heat exchanger receives the products of combustion from the burner. The water conduit is positioned in the heat exchanger in a heat exchange relationship with the products of combustion.
Data Source
AI summary
A method of assembling multiple low NOx burners including the step of assembling multiple bodies, each body including a multiple first burner ports connected to a first burner inlet and multiple second burner ports connected to a second burner inlet. The method also including the step of selecting one of the bodies and inserting a first inlet tube into the second burner inlet to provide a fuel/air mixture to the second burner ports at a first rate. The method also including the step of selecting one of the bodies and inserting a second inlet tube into the second burner inlet to provide the fuel/air mixture to the second burner ports at a second rate different than the first rate.