Oxidative Demetalling Using Flammable Gas Diluent
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Solution Overview
Problem
Current methods for removing metal residues from hydroformylation products, particularly cobalt compounds, face challenges in efficiency and safety due to the need for large amounts of inert gases, which reduce volumetric efficiency and complicate the disposal of offgas streams, and may lead to flammable and explosive mixtures.
Innovation Solution
Introducing a flammable gas as a diluent to oxidize metal residues in the demetalling process, ensuring the gaseous mixture is above its upper flammability limit, thereby increasing efficiency and reducing the amount of diluent required, while ensuring safety by preventing explosive conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large amounts of inert gases are used to remove metal residues, then safety is improved by preventing explosive mixtures, but volumetric efficiency deteriorates and disposal of offgas streams becomes complicated
Solution Approach 1:
The patent changes the chemical composition parameter of the gas phase from inert gas to flammable gas (hydrogen or carbon monoxide), transforming the demetalling process from a safe but inefficient operation to one that is both safe and efficient by maintaining the gas mixture above the upper flammability limit
Solution Approach 2:
The patent reverses the conventional inert atmosphere approach by using a flammable atmosphere controlled to be above the upper flammability limit, eliminating the need for large amounts of inert diluent while maintaining safety through precise composition control
2Reliability
If large amounts of inert gases are used to remove metal residues, then safety is improved by preventing explosive mixtures, but the amount of diluent required increases
Solution Approach 1:
The patent changes the gas composition from inert to flammable, allowing the use of minimal diluent (only enough to maintain composition above UFL) rather than requiring large amounts of inert gas for safety
Solution Approach 2:
The patent converts the potentially harmful flammable gas mixture into a beneficial process medium by controlling it to operate above the upper flammability limit, where the flammability is eliminated while the chemical reactivity remains beneficial for metal residue removal
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 enhances the volumetric efficiency of the reaction system, reduces the need for inert gases, and allows for safer operation by maintaining the gaseous mixture above its upper flammability limit, facilitating more efficient and secure removal of metal residues.
Implementation Method 1
introducing an oxygen-containing gas into the organic reaction product to oxidise metal residues in the product
Data Source
AI summary
Oxidative recovery methods that use oxygen or air for recovery of homogeneous metal catalysts, such as cobalt catalysts, used in for example hydroformylation processes, can be hazardous. Explosive or flammable gas mixtures may be generated inside the process equipment, which can deflagrate upon any ignition source such as a static electricity discharge. The use of a flammable diluent has been found to be a very effective way of optimizing the recovery method, by bringing the resulting gas mixtures above their upper flammability limit. The offgas produced is then also easier to dispose of as a fuel, as compared to when a non-flammable diluent is used.