Isocyanate Production Mixing Device Using Inert Medium Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas-phase phosgenation processes for producing isocyanates face challenges in preventing the formation of solids that can lead to blockages and reduced mixing efficiency due to local oversaturation of reactants, resulting in incomplete reactions and equipment clogging.
Innovation Solution
Incorporating an inert medium into the mixing device to separate the amine and phosgene streams, ensuring they do not mix completely until further downstream, thereby reducing the likelihood of solid formation and enhancing mixing efficiency by maintaining supersaturation and minimizing contact with reactor walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If amine and phosgene streams are mixed directly in conventional mixing devices, then complete mixing is achieved, but solid formation occurs leading to blockages and reduced mixing efficiency
Solution Approach 1:
The mixing process is divided into multiple stages: first stage with direct contact for rapid mixing, second stage with inert medium insertion to separate streams and prevent solid formation. This segmentation allows the system to achieve both complete mixing and reliable blockage-free operation.
Solution Approach 2:
An inert medium is introduced as an intermediary substance between the amine and phosgene streams. This mediator prevents direct contact at certain mixing stages, suppressing solid formation while allowing the reaction to proceed to completion through controlled mixing phases.
2Productivity
If reactant streams are mixed rapidly to achieve complete reaction, then productivity increases, but local oversaturation causes solid formation and equipment clogging
Solution Approach 1:
The mixing process employs periodic action with alternating phases: rapid mixing phases for high productivity, followed by inert medium insertion phases to prevent solid formation. This periodic cycle maintains high reaction speed while avoiding clogging issues.
Solution Approach 2:
The system dynamically changes mixing parameters by controlling the timing and amount of inert medium insertion. This parameter adjustment allows rapid mixing when needed while preventing local oversaturation that leads to solid formation.
3Reliability
If inert medium is metered between amine and phosgene streams, then solid formation is suppressed, but mixing device complexity increases
Solution Approach 1:
The inert medium serves multiple functions: it acts as a separator to prevent solid formation, as a carrier gas to maintain flow, and as a temperature buffer. This multi-functionality justifies the additional device complexity by providing multiple benefits from a single additive component.
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 suppresses the formation of clogging solids, achieves rapid and efficient mixing, and maintains the reactants in a gaseous state, enhancing the production of isocyanates by preventing premature solidification and equipment blockages.
Implementation Method 1
contacting fluid streams of amine, phosgene and inert medium in at least one mixing device and subsequent reaction of amine and phosgene together by metering in an inert medium in the mixing device at least between each amine stream present and each phosgene stream present
Implementation Method 2
the turbulent fluctuation speeds in the educt streams are increased and mixing then takes place more quickly when the two educt streams are combined
Implementation Method 3
the flow rate increases due to the increase in volume during the course of the reaction due to expansion of the gas as a result of the exothermic nature of the reaction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for producing isocyanates.