Flash Evaporation Nanoparticle Preparation

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Solution Overview

Problem

Existing methods for preparing nanoparticles often fail to achieve submicron particle sizes and large-scale production efficiently, as they are limited by solubility in supercritical fluids and struggle with particle recovery, agglomeration, and maintaining the elemental ratio in composite nanoparticles.

Innovation Solution

A method involving heating a solution of organic or inorganic compounds beyond the solvent's boiling point under controlled pressure, followed by rapid expansion through a nozzle for instantaneous evaporation, allowing for the formation and separation of submicron nanoparticles using a combination of electrostatic precipitation and axial cyclones, enabling precise control over particle size and scalable production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If supercritical fluid processes are used to prepare nanoparticles, then nanoparticle formation is achieved, but the particle sizes cannot be truly submicron and production scale is limited

Engineering Contradiction:
Improveparticle size controlVSAvoidproduction capacity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the physical parameters of the system by heating the solution to temperatures above the solvent's boiling point (e.g., 100-200°C) while maintaining elevated pressure (3-300 bar) to prevent premature evaporation. This parameter change enables the solution to remain liquid under superheated conditions, and upon rapid depressurization through the nozzle, causes instantaneous evaporation and supersaturation that produces submicron nanoparticles with precise size control while enabling industrial-scale production

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transitions of the solvent as the core mechanism: the solvent is heated to a liquid state above its boiling point under pressure, then rapidly transitions to vapor phase upon decompression through the nozzle. This sudden phase transition from liquid to vapor causes extreme supersaturation of the dissolved compound, leading to controlled nucleation and formation of monodisperse submicron nanoparticles at industrial production scales

Inventive Principle:
Principle #36Phase transitions

2Adaptability or versatility

If supercritical fluids are used, then nanoparticle preparation is possible, but solubility limitations prevent universal application

Engineering Contradiction:
Improveapplicability to different compoundsVSAvoidsolubility in supercritical fluid
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The invention employs conventional liquids as solvents (water, alcohols, esters, ketones) and changes the temperature and pressure parameters to achieve superheated liquid states. This approach eliminates the solubility constraints of supercritical fluids while maintaining the ability to dissolve a wide range of organic and inorganic compounds, thereby achieving universal applicability across different compound types including pharmaceuticals, agrochemicals, and energetic materials

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If composite nanoparticles are prepared using supercritical fluids, then nanoparticle formation occurs, but the elemental ratio does not match the targeted composite

Engineering Contradiction:
Improveelemental ratio controlVSAvoidsolubility differences of elements
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The invention uses a liquid solvent system with controlled temperature and pressure parameters that allow multiple compounds to co-dissolve without the solubility-selectivity issues of supercritical fluids. By adjusting the solvent type, temperature, and pressure, the process enables precise control over the composition and elemental ratios in composite nanoparticles, ensuring the final product matches the intended stoichiometry

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention achieves homogeneous distribution of multiple compounds in the liquid solution phase before atomization. The liquid solvent system provides uniform solvation of all components, and the rapid evaporation process preserves this homogeneity, resulting in composite nanoparticles with uniform composition and correct elemental ratios throughout the particle structure

Inventive Principle:
Principle #33Homogeneity

4Productivity

If conventional nanoparticle preparation methods are used, then some nanoparticles are produced, but particle recovery is difficult and agglomeration occurs

Engineering Contradiction:
Improveparticle recovery efficiencyVSAvoidparticle dispersion stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention rapidly skips through the intermediate states that lead to agglomeration by using extremely fast atomization and evaporation (occurring in milliseconds). The solution is atomized into fine droplets and evaporates so quickly that nanoparticles form and are immediately carried by the gas flow to the collection system, preventing them from settling and agglomerating. This rapid process enables efficient particle recovery while maintaining dispersion stability

Inventive Principle:
Principle #21Skipping (Rushing through)

Solution Approach 2:

The invention uses pneumatic transport where the evaporated solvent and formed nanoparticles are carried by the gas flow through the system to the collection device. This pneumatic conveyance prevents particle settling and agglomeration during transport, and the use of cyclonic separators or electrostatic precipitators enables efficient recovery of the nanoparticles with high productivity and maintained dispersion stability

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 method effectively produces nanoparticles with sizes ranging from 2 to 100 nm, preventing agglomeration and allowing for high-yield, scalable production of various compounds, including energetic, pharmaceutical, and phytopharmaceutical materials, while maintaining the desired elemental ratios.

Implementation Method 1

heating the solution, under a pressure ranging from 3 to 300 bar, to a temperature higher than the boiling point of the solvent

Methodology Applied
Scientific EffectSuperheating: Superheating

Implementation Method 2

The atomization of the solution after passing through a nozzle causes the expansion and evaporation of the solvent in an extremely short time, generally of the order of a fraction of a second

Methodology Applied
Scientific EffectFlash evaporation: Flash Evaporation

Implementation Method 3

Evaporation of the solvent causes extreme supersaturation of the droplets and the compound crystallizes to form nanoparticles

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 4

separation of the solvent in gaseous form in a solvent separation device from the atomization chamber, said solvent being eliminated by means of a vacuum pump

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP2812104B1Process and device for the preparation of nanoparticles by flash evaporation
Publication Date: 2019.08.14 CENT NAT DE LA RECH SCI (C N R S)
  • EP2812104B1 patent drawingFigure 1
  • EP2812104B1 patent drawingFigure 2

AI summary

The invention relates to the field of preparing nanoparticles. In particular, the invention provides a method for preparing organic or inorganic nanoparticles by instantaneous evaporation or flash evaporation, e.g. for the manufacture of nanoparticles of fertilizers, pharmaceutical or phytopharmaceutical active ingredients, or insensitive energy materials.