Multilayer Diffusion Microreactor for Monodisperse Particle Synthesis
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Solution Overview
Problem
Existing methods for forming fine particles, such as organic pigment particles, face challenges including clogging of reaction channels, instability of liquid flow, and inhomogeneous aggregation due to concentration differences of flocculants, which hinder the production of monodisperse particles in nanometer sizes.
Innovation Solution
A diffusion reaction method and device that utilize a multilayer flow sandwiched by a non-reactive liquid to achieve thin laminar flow without narrowing the reaction channel, allowing for instantaneous mixing and reaction while preventing clogging and adhesion, and enabling both fine particle formation and aggregation in a single process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the reaction channel size is decreased to achieve instantaneous diffusive mixing, then the mixing speed is improved, but the reaction channel becomes clogged by fine particles and liquid flow becomes unstable
Solution Approach 1:
The patent transitions from two-dimensional planar mixing in conventional microreactors to three-dimensional multilayer flow structure. Multiple reaction liquids are stacked in the depth direction (z-axis) to form a multilayer flow, enabling diffusive mixing to occur simultaneously across multiple interfaces without requiring channel narrowing. This dimensional expansion allows instantaneous mixing while maintaining adequate channel size to prevent clogging and flow instability.
Solution Approach 2:
The reaction liquids are segmented into multiple discrete layers flowing parallel to each other in the depth direction. Each layer maintains its identity during flow, creating multiple diffusion interfaces. This segmentation enables controlled diffusive mixing at each interface while preventing complete aggregation that would cause clogging, thus resolving the contradiction between mixing speed and flow stability.
2Speed
If the reaction channel size is decreased to achieve instantaneous diffusive mixing, then the mixing speed is improved, but the device complexity increases due to manufacturing difficulties
Solution Approach 1:
Instead of achieving mixing through reduced channel width (x-y plane), the patent utilizes the depth direction (z-axis) to stack multiple liquid layers. This dimensional shift allows the use of conventional channel widths that are easier to manufacture while still achieving instantaneous mixing through the multilayer configuration and multiple diffusion interfaces.
3Productivity
If acid is added in a tank to achieve flocculation, then the aggregation reaction occurs, but great concentration difference occurs between addition position and distant positions causing inhomogeneous aggregation
Solution Approach 1:
The flocculant is pre-mixed into the poor solvent before the reaction begins, ensuring uniform distribution throughout the reaction liquid. This preliminary action eliminates the concentration gradients that would occur during tank addition, enabling homogeneous aggregation throughout the entire reaction volume simultaneously.
Solution Approach 2:
The patent replaces the mechanical stirring and gradual addition process in a tank with a fluid dynamic system where the pre-mixed flocculant solution flows continuously through the microreactor channels. The laminar flow and diffusion processes automatically ensure uniform distribution without requiring mechanical mixing, thus achieving both high productivity and uniform aggregation.
4Manufacturing precision
If separate apparatuses are used for fine particle formation and aggregate formation, then each process can be optimized, but the device complexity and cost increase
Solution Approach 1:
The patent merges the fine particle formation process and the aggregate formation process into a single integrated microreactor system. By controlling the flow rates, layer configuration, and residence time within the same device, both nucleation/growth of fine particles and subsequent aggregation can occur sequentially in the same channels, eliminating the need for separate apparatuses while maintaining process optimization.
Solution Approach 2:
The microreactor device is designed to perform multiple functions: it serves as both the fine particle formation reactor and the aggregation reactor. The same channel structure supports both nucleation/growth reactions and flocculation reactions by adjusting operational parameters such as flow rates and residence time, thus achieving multi-functionality without increasing device complexity.
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 the production of fine particles with favorable monodisperse properties in nanometer sizes, reduces clogging and adhesion issues, and maintains homogeneous flocculant concentration, enhancing production efficiency and precision.
Implementation Method 1
causing a diffusive mixing between laminar flows so as to cause reaction
Implementation Method 2
diffusively mix a plurality of reaction liquids so that the reaction liquids can instantly react in the reaction channel
Data Source
AI summary
A diffusion reaction method includes: joining a plurality of reaction liquids relating to a reaction to form a multilayer flow; sandwiching from both sides of the multilayer flow in the depthwise direction using sandwiching liquid so that the multilayer flow is contracted and thinned; and flowing the multilayer flow through a reaction channel to cause a diffusive mixing between laminar flows so as to cause the reaction. The method enables to allow reacting diffusive mixing a plurality of reaction liquids instantly in a reaction channel, is suitable for any kinds of reaction product. Further, for example, when forming fine particles in a diffusion reaction, the method can prevent logging of the reaction channel by the fine particles and an adhesion of the fine particles to the wall of the reaction channel.