Static Reactive Jet Mixer for Amine-Phosgene Mixing
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Solution Overview
Problem
Conventional static mixers face challenges in limiting the formation of undesired secondary reactions and by-products during the mixing of phosgene and amine, leading to reduced product quality and increased fouling, which affects the yield and maintenance costs in the production of isocyanates.
Innovation Solution
A static reactive jet mixer with multiple rows of nozzles, including a first row of nozzles for the amine and a secondary row of nozzles positioned to enrich phosgene-deficient regions, is used to enhance mixing and reduce secondary reactions by ensuring uniform phosgene distribution and temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional static mixers are used for mixing phosgene and amine, then the mixing process is simple, but undesired secondary reactions and by-products increase
Solution Approach 1:
The mixer is divided into multiple sections with different nozzle rows (first row, second row, third row) positioned at specific intervals. Each row injects phosgene at different locations to create segmented mixing zones that prevent localized high concentrations and secondary reactions.
Solution Approach 2:
Different regions of the mixer have specialized functions: the first row creates initial mixing, the second row addresses phosgene-deficient regions, and the third row ensures complete distribution. This local optimization of mixing quality prevents secondary reactions in specific zones.
2Manufacturing precision
If phosgene to amine ratio is increased to minimize secondary reactions, then by-product formation decreases, but equipment fouling increases
Solution Approach 1:
The mixer creates preliminary mixing zones where phosgene and amine are partially mixed before reaching the reaction zone. This preliminary action ensures uniform distribution and prevents localized excess phosgene that would cause fouling.
Solution Approach 2:
The mixer structure acts as an intermediary that controls the interaction between phosgene and amine. The multiple nozzle rows and chamber design mediate the mixing process to achieve uniform concentration distribution, preventing both secondary reactions and fouling.
3Manufacturing precision
If mixing is intensified to reduce secondary reactions, then product quality improves, but energy consumption increases
Solution Approach 1:
The mixer uses the kinetic energy of the flowing streams themselves to achieve mixing. The phosgene and amine streams mix through their own momentum and the geometry of the chamber, eliminating the need for external mixing energy input.
Solution Approach 2:
The system uses fluid dynamics and pressure differentials to drive the mixing process. The injection of phosgene through multiple nozzle rows creates turbulent mixing patterns that are driven by the fluid flow itself rather than external mechanical energy.
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 proposed mixer design effectively minimizes the formation of urea and other undesired by-products, improving product quality and reducing fouling, thereby increasing the yield and reducing maintenance costs by ensuring better mixing and temperature management.
Implementation Method 1
Static mixers generally have no prominent moving parts and instead rely on pressure differentials within the fluids being mixed to facilitate mixing
Implementation Method 2
The chemical reaction can be depicted as follows: Amine + COCl2 -> HCl + Carbamyl Chloride
Implementation Method 3
The reaction between the amine and phosgene normally occurs at conditions where there are both mass-transfer limited or mixing controlled as well as kinetically controlled reactions
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
This disclosure relates to a static mixer (1) with a plurality of nozzles, and more generally, to a mixer and method of use thereof for mixing phosgene and amine with shaped jets or at least two rows of nozzles (15,16)where the second row (16) is used to enrich an area of deficit of the phosgene flow within the static reactive jet mixer (1). Configurations of enriching secondary flow include the use of concentric, eccentric, or offset jets of amine/phosgene, and the use of nozzles with different and irregular geometries to help focus amine/phosgene to a specific area of the principal phosgene flow.