Fluid Combustion Device with Flame Arrester for Flare Pilot

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Solution Overview

Problem

Fluid combustion devices for flare pilots are prone to flame extinguishment due to moisture-induced corrosion and flashback, leading to unreliable pilot flames and potential hazards, especially under varying environmental conditions and fuel supply interruptions.

Innovation Solution

A fluid combustion device with a symmetrical air inlet arrangement around the primary flow axis, incorporating a flame arrester element and a mixing chamber to enhance air entrainment and prevent flashback, ensuring reliable ignition and flame stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If air is continuously supplied at pressure to the flare pilot, then the pilot flame can be maintained, but the system becomes vulnerable to flame extinguishment when air supply is interrupted or stopped

Engineering Contradiction:
Improvepilot flame reliabilityVSAvoidair supply system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The flare pilot system uses the fuel gas flow itself to draw in and mix with air through the venturi effect, eliminating the need for external compressed air supply systems. The fuel gas flowing through the mixing chamber creates a pressure drop that automatically entrains air, making the system self-sufficient and removing the vulnerability associated with external air supply interruptions

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system utilizes pneumatic principles through the venturi effect, where the flowing fuel gas creates a pressure differential that draws air into the mixture automatically. This pneumatic mechanism replaces the need for pressurized air supplies and complex control systems, simplifying the overall device while maintaining reliable combustion

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If multiple flare pilots are provided around the flare stack, then the possibility of pilot flame extinguishment is mitigated, but the device complexity and cost increase

Engineering Contradiction:
Improveignition reliabilityVSAvoidnumber of pilots
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the operational parameters of the flare pilot by using a flame front propagation mechanism instead of a traditional continuous pilot flame. The flame front is generated by igniting the pre-mixed fuel-air mixture in the downstream conduit, creating a traveling flame that reliably ignites the main flare gas without requiring multiple pilots or continuous burning

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The downstream conduit acts as an intermediary chamber where fuel and air are pre-mixed and ignited before the flame reaches the main flare stack. This intermediate mixing and ignition process ensures reliable flame propagation without requiring multiple pilot flames, simplifying the overall system while maintaining ignition reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If an ignition means is provided to reignite the pilot flame, then flame extinguishment can be corrected, but the system complexity increases and response time is delayed

Engineering Contradiction:
Improveflame maintenanceVSAvoidreignition time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system maintains continuous readiness for ignition by keeping the fuel-air mixture constantly prepared in the mixing chamber and downstream conduit. When ignition is needed, the flame front propagates immediately through the pre-prepared mixture, eliminating delays associated with traditional reignition systems that require separate ignition sequences and component activations

Inventive Principle:
Principle #20Continuity of useful action

4Quantity of substance

If the flow area of the flow conduit increases or decreases at the air inlet, then air entrainment is enhanced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveair entrainmentVSAvoidflow conduit geometry
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The flow conduit is segmented into distinct sections: an upstream section with constant cross-section, a mixing chamber where air is entrained, and a downstream section leading to the ignition point. This segmentation allows the air inlet to have a simplified geometry with a sudden area change, which is easier to manufacture with standard tolerances while still achieving effective air entrainment through the venturi effect in the mixing chamber

Inventive Principle:
Principle #1Segmentation

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 solution provides a reliable and efficient combustion process, minimizing the risk of flashback and corrosion, resulting in a stable and robust flame front that consistently ignites and maintains the pilot flame, even under challenging conditions.

Implementation Method 1

the flow area of the flow conduit increases and/or decreases at, adjacent or upstream of the air inlet or inlets to encourage air to be entrained, in use, into a flow of fuel passing through the flow conduit

Methodology Applied
Scientific EffectAir entrainment: Entrainment

Implementation Method 2

the flow area of the flow conduit increases and/or decreases at, adjacent or upstream of the air inlet or inlets to encourage air to be entrained

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 3

the fuel and air mixture is ignited downstream of the mixing chamber, generating a flame front which travels along the downstream conduit to a distal end

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3446037B1Fluid combustion device
Publication Date: 2020.03.18 ELMAC TECH
  • EP3446037B1 patent drawingFigure 1~3
  • EP3446037B1 patent drawingFigure 4~5
  • EP3446037B1 patent drawingFigure 6~9

AI summary

A fluid combustion device (3) for use with a flare pilot, the fluid combustion device (3) includes a flow conduit with a fuel inlet (5), an outlet (6), a primary flow path through the flow conduit and a continuous air inlet (74) between the fuel inlet (5) and the outlet (6), wherein the air inlet (74) includes a protection means (8A) (e.g. a flame arrester element (8)) mounted in or on or otherwise associated therewith, wherein air is entrained, in use, into a flow of fuel passing along the flow conduit for ignition in, at or downstream of the outlet (6) to produce a flame front.