Flame Spray Pyrolysis Reactor Design for Low Carbon Metal Oxide Powders

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Solution Overview

Problem

The understanding of how process parameters in flame spray pyrolysis influence the properties of metal oxides and silicon dioxide powders is incomplete, and there are challenges in implementing carbon-containing starting materials while maintaining high throughput.

Innovation Solution

A process where an aerosol containing a metal and/or silicon compound is introduced into a flame in a reactor, with a specific ratio of spray area to reactor cross-sectional area, and precise control of oxygen and fuel gases to optimize conversion, resulting in high-surface-area powders with low carbon content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If carbon-containing starting materials are used in flame spray pyrolysis, then the variety of metal oxide products can be expanded, but the complete conversion of starting materials becomes difficult to achieve

Engineering Contradiction:
Improvevariety of metal oxide productsVSAvoidcomplete conversion of starting materials
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the flame by introducing oxygen-containing gases (air, oxygen, carbon dioxide, water vapor) to modify the oxidation environment. This enables complete conversion of carbon-containing starting materials while maintaining the ability to produce various metal oxide products by adjusting the precursor composition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces oxygen-containing gases to provide additional oxygen for complete oxidation of carbon-containing precursors. This accelerated oxidation ensures thorough conversion of starting materials, eliminating residual carbon and achieving complete transformation to metal oxides while preserving product versatility.

Inventive Principle:
Principle #38Strong oxidants (Accelerated oxidation)

2Productivity

If the spray area ratio is increased to improve aerosol distribution, then the conversion efficiency improves, but the reactor design becomes more constrained

Engineering Contradiction:
Improveconversion efficiencyVSAvoidreactor design constraints
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent optimizes the spray area to reactor cross-sectional area ratio parameter within the range of 0.2-0.8 to achieve optimal aerosol distribution and conversion efficiency. This parameter optimization balances productivity improvement with practical reactor design considerations, avoiding excessive complexity.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the flame temperature is increased to accelerate reaction kinetics, then the conversion rate improves, but the risk of incomplete combustion of carbon-containing materials increases

Engineering Contradiction:
Improveconversion rateVSAvoidcomplete combustion of carbon-containing materials
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces oxygen-containing gases to ensure sufficient oxygen supply for complete combustion of carbon-containing materials. This prevents incomplete combustion and formation of unwanted carbonaceous residues, even at elevated flame temperatures that accelerate reaction kinetics.

Inventive Principle:
Principle #38Strong oxidants (Accelerated oxidation)

Solution Approach 2:

The patent utilizes the combustion process itself to generate heat that sustains the reaction, creating a self-regulating system where the exothermic combustion provides the necessary temperature for high conversion rates while the oxygen-containing gases ensure complete oxidation of carbon-containing precursors.

Inventive Principle:
Principle #23Feedback

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 process achieves high-surface-area metal oxides and silicon dioxide powders with low carbon content, improving the control over product properties and throughput.

Implementation Method 1

the aerosol is obtained by atomizing a metal and/or silicon compound and an atomizing gas together by means of one or more nozzles

Methodology Applied
Scientific EffectAtomization:

Implementation Method 2

the flame is formed by igniting an oxygen-containing gas (1) with a fuel gas

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

an aerosol containing a metal and/or silicon compound is introduced into a flame in a reactor and reacted there

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

flame spray pyrolysis

Methodology Applied
Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentEP3313783B1Method for the preparation of metal oxide powders using flame spray pyrolysis
Publication Date: 2020.10.21 EVONIK OPERATIONS GMBH

AI summary

Process for producing metal oxide powders by means of flame spray pyrolysis, in which an aerosol comprising a metal compound is introduced into a flame in a reactor and reacted therein, and the metal oxide powder obtained is separated from gaseous substances, wherein a) the flame is formed by the ignition of an oxygen-containing gas (1) with a fuel gas, b) the aerosol is obtained by joint atomization of a solution containing a metal compound and an atomization gas by means of one or more nozzles and c) the ratio of the spray area to the cross-sectional reactor area is at least 0.2.