Crossflow Membrane Emulsification for Reactive Crystallisation
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Solution Overview
Problem
Current reactor configurations are inadequate for controlling precipitation reactions effectively, leading to frequent blockage and inadequate control of particle size, shape, and product purity in the production of micro/nanoparticles and inorganic materials.
Innovation Solution
The use of a crossflow membrane emulsification apparatus (AXF) with a tubular membrane and optional insert, which generates laminar mixing of liquid reactants, creating a reactive mixing environment suitable for the production of small, non-aggregated solid particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional reactor configurations are used for precipitation reactions, then the reaction can proceed, but frequent blockage occurs and control of particle size, shape, and product purity is inadequate
Solution Approach 1:
The reactor is segmented into distinct functional zones: a mixing zone with high shear rates for nucleation, and a growth zone with lower shear rates for crystal growth. This spatial segmentation allows independent control of nucleation and growth processes, preventing blockage while achieving precise particle size control
Solution Approach 2:
Different regions of the reactor are designed with locally optimized flow conditions and mixing intensities. The mixing zone employs high-energy impellers for intense local mixing to control nucleation, while the growth zone uses gentler conditions to control crystal growth, thereby achieving both reliability and manufacturing precision
2Manufacturing precision
If separate reaction and recrystallisation steps are used, then each process can be optimized, but time and cost increase along with the need for additional reagents and energy
Solution Approach 1:
The reaction and crystallisation processes are merged into a single continuous reactor system. Reactants are fed continuously into the mixing zone where nucleation occurs, and the slurry flows automatically into the growth zone for crystal growth, eliminating the need for separate batches and intermediate handling steps
Solution Approach 2:
The reactor operates in continuous mode with steady-state feed rates and flow conditions. This continuous operation maintains constant supersaturation levels and flow velocities, enabling uninterrupted nucleation and crystal growth without the start-stop cycles inherent in batch processes, thereby reducing production time while maintaining control
3Manufacturing precision
If high supersaturation is used to produce small crystals, then nucleation rates increase, but control over crystal size distribution becomes more difficult
Solution Approach 1:
The reactor employs dynamic control of flow rates and mixing intensities. The feed rate of reactants and the agitation speed are continuously adjusted to maintain optimal supersaturation levels throughout the process, preventing runaway nucleation while ensuring consistent crystal size distribution
Solution Approach 2:
Online particle size measurement systems monitor the crystal size distribution in real-time, and this data feeds back to control the feed rate and mixing conditions. This closed-loop control automatically adjusts operating parameters to maintain narrow crystal size distribution even at high nucleation rates
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 scalable and continuous production of small, uniform solid particles with improved control over particle size distribution and product purity, reducing the need for additional downstream processing.
Implementation Method 1
a membrane defining a plurality of pores; controlling provision of a first liquid phase through a membrane
Implementation Method 2
generates laminar mixing of liquid reactants, creating a reactive mixing environment
Implementation Method 3
supersaturating the third liquid phase to form solid particles of the third material
Implementation Method 4
reacting the first a second materials to produce a third liquid phase comprising a solution of a third material; supersaturating the third liquid phase to form solid particles
Implementation Method 5
supersaturating the third liquid phase to form solid particles of the third material
Data Source
AI summary
There is described a method of preparing solid particles of a material, said method comprising controlling provision of a first liquid phase, wherein said first liquid phase comprises a solution of a first material through a membrane, said membrane defining a plurality of pores; and controlling provision of a second liquid phase, wherein said second liquid phase comprises a solution of a second material; reacting the first a second materials to produce a third liquid phase comprising a solution of a third material; and supersaturating the third liquid phase to form solid particles of the third material.