Attenuating Material Deflagration Pressure Wave Fragmentation

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Solution Overview

Problem

Current methods for controlling and suppressing explosions of combustible gases in process vessels, such as tubular reactors, are inadequate as they often rely on heat absorption or introducing suppressants after ignition, which are ineffective in high-temperature and pressure conditions, leading to incomplete quenching of combustion and potential detonation.

Innovation Solution

The method involves selecting and placing attenuating materials in the tubular reactor's defined regions, which occupy at least 20% of the volume, with specific geometries and effective diameters to deflect and fragment the deflagration pressure wave, thereby preventing transition to detonation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heat-absorbing materials (heat sinks) are used to prevent flame-front propagation, then combustion zone heat-energy is removed, but the method is ineffective in high-temperature and pressure conditions leading to incomplete quenching

Engineering Contradiction:
Improveeffectiveness of combustion suppressionVSAvoidhigh-temperature conditions
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent replaces thermal-based combustion suppression (heat sinks) with a mechanical approach using deflagration pressure attenuation. Attenuating materials physically fragment and redirect the deflagration pressure wave through tortuous pathways, reducing peak pressure and preventing detonation transition without relying on heat absorption mechanisms that fail at high temperatures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental parameter from thermal management to pressure management. Instead of attempting to remove heat-energy from the combustion zone, the system focuses on attenuating the deflagration pressure wave by using materials with specific geometries and arrangements that create tortuous flow paths, thereby reducing peak pressure below detonation thresholds.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If suppressants are introduced after ignition to suppress deflagration, then combustion propagation is slowed, but the method is ineffective in high-temperature and pressure conditions leading to incomplete quenching

Engineering Contradiction:
Improveeffectiveness of deflagration suppressionVSAvoidhigh-temperature conditions
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The attenuating materials are pre-installed in the reactor before operation, positioned to intercept and fragment the deflagration pressure wave immediately upon ignition. This preliminary placement ensures that the pressure attenuation mechanism is already in place and operational, eliminating the delay associated with introducing suppressants after ignition detection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces chemical suppressant introduction with a passive mechanical pressure attenuation system. The attenuating materials physically fragment and redirect the pressure wave through tortuous pathways, providing reliable suppression that does not depend on chemical reactions or timing of suppressant delivery, and remains effective under high-temperature and pressure conditions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If attenuating materials with small effective diameters are used to fragment pressure wave, then deflagration pressure is reduced, but device complexity increases

Engineering Contradiction:
Improvedeflagration pressure attenuationVSAvoidattenuating material configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The attenuating materials are divided into discrete components with specific effective diameter ranges (0.5-5 cm), arranged to create tortuous pathways throughout the reactor volume. This segmentation allows the pressure wave to be fragmented into multiple smaller waves, reducing peak pressure while using manageable material sizes that do not excessively complicate the device structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies attenuating materials with specific local properties (effective diameter, geometry, distribution) at specific locations within the reactor where deflagration pressure attenuation is most needed. This localized approach optimizes pressure attenuation effectiveness while minimizing overall device complexity by concentrating attenuating materials in critical regions rather than uniformly throughout the entire reactor.

Inventive Principle:
Principle #3Local quality

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 effectively reduces the maximum deflagration pressure, slowing the propagation of the pressure wave and flame front, thereby quenching the deflagration event and preventing detonation, even in high-temperature and pressure conditions.

Implementation Method 1

deflect and fragment the deflagration pressure wave, thereby preventing transition to detonation

Methodology Applied
Scientific EffectPressure wave deflection and fragmentation: Shock Wave

Implementation Method 2

This approach effectively reduces the maximum deflagration pressure, slowing the propagation of the pressure wave and flame front

Methodology Applied
Scientific EffectHeat absorption: Heat Sink

Data Source

PatentEP2106848B1Method and apparatus for deflagration pressure attenuation
Publication Date: 2019.10.02 ROHM & HAAS CO
  • EP2106848B1 patent drawingFigure 1
  • EP2106848B1 patent drawingFigure 2~3B
  • EP2106848B1 patent drawingFigure 4A

AI summary

A method for attenuating deflagration pressure produced by combustion of combustible gas in a defined region of a process vessel. The method generally comprises selecting and placing attenuating material in the defined region of the process vessel, wherein the selected attenuating material maintains its physical shape under the operating conditions. The attenuating material should occupy at least 20% of the volume of the defined region of the process vessel. Use of the inventive method may be beneficially applied for the safe operation of oxidation reactors with flammable, high hydrocarbon concentration feeds in order to attain increased productivity. The invention also provides a tubular reactor adapted for attenuation of deflagration pressure resulting from combustion of combustible gas in a defined region therein, wherein the defined region of the tubular reactor comprises attenuating material selected in accordance with the aforesaid method for attenuating deflagration pressure and which have a plurality of components which are placed such that void spaces and open pathways between the components are minimized. A method for performing gas phase reactions safely under flammable operating conditions is also provided, wherein a gas feed composition comprising a hydrocarbon and oxygen is subjected reaction in a reaction vessel having attenuating materials therein and the reaction is conducted at a temperature and a pressure which render the reaction system flammable. By using the inventive apparatus, full pressure containment may be achieved, thereby eliminating the need for emergency pressure relief devices.