Hollow Flame Burner with Envelope Structure

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Solution Overview

Problem

Existing burner technologies face challenges in reducing NOx emissions and achieving efficient heat transfer while managing fuel costs, often requiring complex designs and recirculation systems that can be costly and pose safety risks, especially when dealing with special substances that do not burn easily.

Innovation Solution

The method involves creating an overall flame with internal exhaust gas recirculation within a cup-shaped cavity, eliminating the need for a central flame kernel and allowing for easy modulation of burner output, using basic and additional nozzles with controlled combustion air to achieve NOx reduction and efficient heat transfer without external recirculation devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If direct convection of a hot flame on the boiler wall is used for heat transfer, then heat transfer efficiency is improved, but NOx emissions increase

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidNOx emissions
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The flame is segmented into multiple individual flames arranged in a circle, which form an envelope flame structure. This segmentation allows the flame to be divided into zones with different temperatures and functions, enabling efficient heat transfer from the outer envelope while protecting the inner core

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a nested flame structure where individual flames form an outer envelope that contains and protects an inner core flame. The envelope flame acts as a protective layer that enables efficient heat transfer to the boiler wall while shielding the core flame, creating a nested configuration that resolves the contradiction between heat transfer efficiency and NOx emissions

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If a central core flame is used for reliable combustion, then combustion stability is improved, but internal exhaust gas recirculation increases NOx reduction

Engineering Contradiction:
Improvecombustion stabilityVSAvoidNOx content
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The combustion system is segmented into multiple individual nozzles spaced apart from the center, each producing individual flames. This segmentation eliminates the need for a central core flame while maintaining combustion stability through the distributed arrangement of flames that collectively provide reliable combustion

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of placing the ignition and stability function in the center (conventional approach), the patent inverts the approach by spacing nozzles apart from the center and using the envelope flame structure to provide stability. The individual flames collectively ensure reliable combustion without requiring a central core, and the envelope structure naturally creates external recirculation that reduces NOx

Inventive Principle:
Principle #13The other way round (Inversion)

3Object-generated harmful factors

If external exhaust gas recirculation is used for NOx reduction, then NOx emissions are reduced, but device complexity and safety risks increase

Engineering Contradiction:
ImproveNOx emissionsVSAvoidrecirculation system complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The flame structure itself automatically creates the exhaust gas recirculation through its geometry and flow dynamics. The envelope flame configuration naturally induces external recirculation of exhaust gases around the individual flames, eliminating the need for separate recirculation devices. The system serves itself by using the flame structure to generate the recirculation needed for NOx reduction

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts the recirculation function from separate external devices and integrates it directly into the flame structure itself. The envelope flame configuration inherently creates the recirculation flow, removing the need for complex external recirculation systems and their associated safety risks

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If individual flames are spaced apart to form an envelope flame, then heat transfer is improved, but flame stability may be compromised

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidflame stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent merges multiple individual flames into a unified envelope flame structure. While the individual nozzles are spaced apart to enable heat transfer, their combined effect creates a cohesive envelope that provides stability. The individual flames work together as a integrated system, merging their effects to achieve both heat transfer efficiency and stability

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

This approach significantly reduces NOx emissions, increases efficiency, and lowers manufacturing and operating costs, while enabling flexible fuel management and safe combustion of difficult-to-burn substances, without compromising exhaust gas detoxification.

Implementation Method 1

the radiation of a flame is of course also important for the heat transfer

Methodology Applied
Scientific EffectRadiation: Radiation

Implementation Method 2

the direct convection of a hot flame on the boiler wall is particularly favorable for heat transfer to the heat transfer material

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

internal exhaust gas recirculation with the individual flames of the envelope flame

Methodology Applied
Scientific EffectInternal exhaust gas recirculation:

Implementation Method 4

an overall flame with internal exhaust gas recirculation within a cup-shaped cavity

Methodology Applied
Scientific EffectRecirculation:

Data Source

PatentEP2126471B1Hollow flame
Publication Date: 2016.02.10 DREIZLER ULRICH
  • EP2126471B1 patent drawingFigure 1~2
  • EP2126471B1 patent drawingFigure 3~4
  • EP2126471B1 patent drawingFigure 5

AI summary

Disclosed are a method and an burner apparatus for burning oil and/or gas as fuel. In said method and apparatus, a combined flame (16,3) is generated by means of individual flames (16.1 and 16.2), and a hollow flame is formed within the combined flame, downstream of a fire tube (1) and upstream of the combustion process. In a separate embodiment, exhaust gas can recirculate within said hollow flame. A baffle plate (3) that is disposed inside the air flow is an important structural element for forming the hollow flame.