Segmented Combustor Design for Low NOx Emissions

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Solution Overview

Problem

Existing gas water heaters emit high levels of nitrogen oxides due to inefficient combustion processes, contributing to environmental pollution.

Innovation Solution

A combustor design featuring a combination of lean and rich combustion zones, with specific ratios of air to fuel gas and strategically positioned flame ports, along with a rectifying device, to stabilize the flame structure and reduce nitrogen oxide emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional combustion process is used in gas water heater, then combustion efficiency is maintained, but nitrogen oxide emissions increase causing environmental pollution

Engineering Contradiction:
Improvenitrogen oxide emissionsVSAvoidcombustion efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The combustion process is segmented into three distinct zones: rich combustion zone (excess fuel), stoichiometric combustion zone (perfect air-fuel ratio), and lean combustion zone (excess air). This segmentation allows different parts of the flame to operate at optimal conditions, reducing peak temperatures that generate nitrogen oxides while maintaining overall combustion efficiency through the synergistic effect of all zones

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the combustor are given different local qualities through varied air-fuel ratios. The rich combustion zone uses fuel-excess mixture for stable ignition, the stoichiometric zone achieves complete combustion, and the lean combustion zone uses air-excess mixture to cool the flame and reduce nitrogen oxide formation. Each zone's specific characteristics are optimized for its particular function in the overall combustion process

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If flame temperature is reduced to minimize nitrogen oxide emissions, then environmental pollution decreases, but flame stability deteriorates

Engineering Contradiction:
Improvenitrogen oxide emissionsVSAvoidflame stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The combustion system is divided into multiple zones with different air-fuel ratios, where the rich combustion zone provides stable flame anchoring and the lean combustion zone reduces temperature. The interaction between these zones maintains flame stability while controlling emissions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple combustion zones (rich, stoichiometric, and lean) into a single integrated combustor system. The rich combustion zone's stable flame structure merges with the lean combustion zone's low-temperature characteristics, achieving both flame stability and reduced nitrogen oxide emissions simultaneously

Inventive Principle:
Principle #5Merging (Combining)

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 combustor design improves flame stability, reduces flame temperature, and effectively minimizes nitrogen oxide emissions, thereby enhancing environmental sustainability.

Implementation Method 1

combustion of the fuel gas will produce harmful gas inevitably

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3546827B1Burner and gas water heater provided with same
Publication Date: 2021.06.30 WUHU MIDEA KITCHEN & BATH APPLIANCES MFG CO LTD
  • EP3546827B1 patent drawingFigure 1
  • EP3546827B1 patent drawingFigure 2
  • EP3546827B1 patent drawingFigure 3~4

AI summary

A combustor (100) and a gas water heater having the same are provided, wherein the combustor (100) comprises at least one combustion unit (1), a primary air adjusting plate (2) and a secondary air adjusting plate (3), wherein a combustor shell (11) of the combustion unit (1) is provided with a rich combustion injection port (131) and a lean combustion injection port (121), the primary air adjusting plate (2) is disposed in front of the rich combustion injection port and the lean combustion injection port, so as to adjust an amount of injection air, and the secondary air adjusting plate (3) is disposed below the combustion unit, wherein the primary air adjusting plate (2) extends downwardly and defines a pressure balancing chamber (21) between the primary air adjusting plate (2) the and the secondary air adjusting plate (3).