Catalytic Reactor Flame Arrestor and Modular Catalyst Assembly

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Solution Overview

Problem

Existing catalytic reactors face challenges in preventing auto-ignition of hydrocarbon and oxygen mixtures during the mixing process, which can lead to unwanted combustion and catalyst degradation, especially when operating with reduced oxygen proportions, and pose difficulties in catalyst replacement and maintenance.

Innovation Solution

A catalytic reactor design featuring a mixing section with a flame arrestor made of porous material to inhibit flame propagation, combined with a modular catalyst assembly for easy installation and replacement, and a pressure vessel configuration that isolates the catalyst from insulation to prevent reaction and maintain safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reactants are mixed rapidly to prevent combustion in the mixing section, then safety is improved, but mixing efficiency and reaction completeness deteriorate

Engineering Contradiction:
ImprovesafetyVSAvoidmixing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The mixing section is divided into multiple zones with different mixing intensities. A first mixing zone provides intense mixing to prevent combustion, while a second mixing zone provides gentler mixing to ensure complete reaction. This segmentation allows the system to achieve both safety and mixing efficiency by applying different mixing strategies in different spatial regions.

Inventive Principle:
Principle #1Segmentation

2Productivity

If oxygen proportion is reduced for partial oxidation, then product selectivity is improved, but flame stability and combustion control worsen

Engineering Contradiction:
Improveproduct selectivityVSAvoidflame stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Different regions of the reactor are provided with different oxygen concentrations and mixing intensities. The first mixing zone uses intense mixing with controlled oxygen addition to prevent premature combustion, while the second mixing zone optimizes oxygen distribution for complete reaction. This local differentiation allows the system to maintain flame stability during partial oxidation while achieving high product selectivity.

Inventive Principle:
Principle #3Local quality

3Duration of action of stationary object

If catalyst is isolated from insulation to prevent reaction, then catalyst lifespan is improved, but thermal efficiency and heat transfer deteriorate

Engineering Contradiction:
Improvecatalyst lifespanVSAvoidthermal efficiency
Core Design Contradiction:
Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

A thermal barrier coating or intermediate layer is introduced between the catalyst and the insulation material. This intermediary layer prevents direct contact and chemical reaction between the catalyst and insulation, preserving catalyst lifespan, while still allowing efficient heat transfer from the reaction zone to maintain thermal efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If mixing chamber residence time is reduced to prevent combustion, then safety is improved, but mixing completeness and reaction quality worsen

Engineering Contradiction:
ImprovesafetyVSAvoidreaction quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The mixing intensity and flow dynamics are dynamically adjusted along the flow path. The first mixing zone uses high-intensity dynamic mixing to rapidly disperse reactants and prevent combustion, while the second mixing zone transitions to lower-intensity mixing that allows sufficient residence time for complete reaction. This dynamic approach maintains safety while ensuring reaction quality.

Inventive Principle:
Principle #15Dynamics

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 design effectively prevents stable flame propagation in the mixing chamber, ensures safe operation with reduced oxygen proportions, and facilitates easier catalyst maintenance, improving reactor efficiency and safety while allowing for the use of less expensive materials.

Implementation Method 1

The flame arrestor is formed of a mass of porous material that permits mixing in both radial and axial directions of said mixing chamber

Methodology Applied
Scientific EffectPorous material filtration: Porosity

Implementation Method 2

The flame arrestor is formed of a mass of porous material that permits mixing in both radial and axial directions of said mixing chamber

Methodology Applied
Scientific EffectPorous flow: Porosity

Data Source

PatentEP1993722B1Catalytic reactor
Publication Date: 2011.09.21 PRAXAIR TECH INC
  • EP1993722B1 patent drawingFigure 1
  • EP1993722B1 patent drawingFigure 2~3
  • EP1993722B1 patent drawingFigure 4~4A

AI summary

A catalytic reactor having a mixing section (10) connected to a downstream reaction section (12) containing a catalyst (44) to promote a reaction of oxygen and a hydrocarbon fed to the catalytic reactor. The mixing section (10) is provided with a flame arrestor (30) to prevent a stable flame from propagating should any reaction of oxygen and hydrocarbons occur during mixing. The flame arrestor (30) permits flow in both axial and radial directions to promote mixing. Baffle elements (32) and a downstream static mixer (34) can also be used. The catalyst (44) is preferably in the form of monolithic blocks (46) enclosed by a ceramic tube (48) that is maintained as a unitary catalyst assembly (44) that can be removed for replacement and installation of the catalyst (44) as a single unit.