Concentric Annular Gap Reactor for Isocyanate Phosgenation
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Solution Overview
Problem
Existing gas-phase phosgenation processes for producing isocyanates face challenges in scaling up due to issues with mixing efficiency and clogging, as reactor geometries designed for smaller scales become inadequate for industrial applications, leading to reduced throughput and increased solid deposition on reactor walls.
Innovation Solution
The process involves reacting multiple amine streams with multiple phosgene streams in a reactor, where all streams are metered into concentric annular gaps around the reactor's longitudinal axis, ensuring thorough mixing and maintaining reactants in the gas phase to prevent clogging and maintain efficiency at larger scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reactor geometry is scaled up for industrial production, then throughput increases, but mixing efficiency deteriorates due to increased diameter requiring longer mixing distances
Solution Approach 1:
The reactor is designed with multiple concentric annular gaps instead of a single large gap, segmenting the flow paths to maintain effective mixing distances while accommodating larger overall throughput capacity
Solution Approach 2:
The invention transitions from a single-plane mixing approach to a multi-layer concentric annular gap structure, utilizing the radial dimension to create multiple independent mixing zones that maintain efficiency at scaled dimensions
2Productivity
If reactor geometry is scaled up for industrial production, then throughput increases, but solid deposition on walls increases leading to clogging
Solution Approach 1:
Multiple concentric annular gaps segment the flow into separate channels, preventing solid deposition in any single gap while maintaining high velocity flow that reduces clogging throughout the system
Solution Approach 2:
The design maintains specific velocity and flow rate parameters across all annular gaps to ensure conditions that prevent solid deposition even at industrial scale throughputs
3Device complexity
If single amine stream is reacted with single phosgene stream, then device complexity is low, but mixing efficiency is insufficient for industrial scale
Solution Approach 1:
The reactor structure is segmented into multiple concentric annular gaps with separate amine and phosgene streams, creating multiple mixing zones that collectively achieve superior mixing efficiency while maintaining a relatively simple overall reactor design
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 allows for efficient gas-phase phosgenation on an industrial scale by ensuring thorough mixing and maintaining reactants in the gas phase, preventing clogging and maintaining high reaction efficiency and throughput.
Implementation Method 1
Gas-phase phosgenation is characterized in that the reaction conditions are chosen so that at least the reaction components diamine, diisocyanate and phosgene are gaseous under these conditions
Implementation Method 2
n amine streams are reacted with n+1 phosgene streams in a reactor, where n is a positive integer of at least 1, and all the amine and phosgene streams are each metered into the reactor via annular gaps for mixing
Data Source
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AI summary
The invention relates to a method for producing isocyanates and a device suitable therefor and to the use thereof.