Inorganic Aerogel Particle Preparation via Supercritical Spray Drying
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Solution Overview
Problem
Existing methods for preparing inorganic aerogels do not effectively merge the chemical gel formation step with the subsequent drying step, resulting in insufficient porosity and particle size in the final product.
Innovation Solution
A process involving spraying a composition suitable for forming an inorganic gel into supercritical carbon dioxide, followed by supercritical liquid extraction, where the ratio of spraying time to gelation time is controlled between 0.2 and 0.99, allowing for the production of aerogel particles with tailored particle characteristics, porosity, and pore size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If batch hydrolysis and condensation reactions are used to form gels, then gel formation occurs, but the resulting aerogels have insufficient porosity and particle size
Solution Approach 1:
The patent replaces traditional batch chemical processing with a spray-drying system that uses fluid dynamics and mass transfer to achieve gel formation. The composition is sprayed into droplets that undergo rapid solvent exchange and gelation in the gas phase, eliminating the need for batch hydrolysis and condensation reactions while achieving superior porosity and particle size control
Solution Approach 2:
The patent changes the physical and chemical parameters of the system by controlling the spray droplet size, solvent composition, and environmental conditions during drying. By adjusting parameters such as spray temperature, humidity, and solvent volatility, the process achieves optimal porosity and particle characteristics that cannot be obtained through conventional batch methods
2Manufacturing precision
If conventional drying methods are used after gel formation, then liquid removal occurs, but the aerogel structure collapses resulting in low porosity
Solution Approach 1:
The patent performs preliminary action by forming the gel structure within the spray droplet before the drying process begins. The gelation occurs during the spray flight or immediately upon contact with the drying environment, creating a pre-formed network that resists collapse during subsequent solvent removal. This preliminary gel formation protects the aerogel structure while enabling rapid drying
Solution Approach 2:
The patent combines gel formation and drying into a continuous spray-drying process rather than separate batch operations. The composition is sprayed as a continuous stream of droplets that simultaneously undergo solvent exchange and gelation, maintaining the aerogel structure throughout the process. This continuous action eliminates the need for prolonged drying times while preserving porosity
3Manufacturing precision
If particle precipitation processes are used, then particles are formed, but the process complexity increases and particle size control is insufficient
Solution Approach 1:
The spray-drying system performs multiple functions simultaneously: it atomizes the composition into droplets, provides rapid solvent exchange, induces gelation, and dries the particles all in one continuous process. This multi-functional approach replaces multiple separate unit operations required by conventional particle precipitation methods, reducing equipment complexity while achieving precise particle size control through spray parameter adjustment
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 enables the production of highly porous and tailored aerogel particles with improved particle size and porosity, achieving high surface areas and pore volumes, suitable for applications such as thermal insulation and biomedical uses.
Implementation Method 1
spraying the composition (I) into supercritical carbon dioxide at a spraying time ts to obtain gel particles
Implementation Method 2
drying the gel particles obtained in step (ii) by supercritical liquid extraction
Data Source
AI summary
The present invention is directed to a process for preparing an inorganic aerogel, the process comprising the steps of providing a composition (I) suitable to form an inorganic gel with a gelation time tG, spraying the composition (I) into supercritical carbon dioxide at a spraying time ts to obtain gel particles, and drying the gel particles obtained in step (ii) by supercritical liquid extraction, wherein the ratio ts : tG is in the range of from 0.2 to 0.99. The present invention further is directed to the inorganic aerogel as such as well as the use of the inorganic aerogel according to the invention in particular for medical and pharmaceutical applications or for thermal insulation.