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New generation of nanoporous organic and hybrid aerogels for industrial applications: from the lab to pilot scale production

Periodic Reporting for period 3 - NanoHybrids (New generation of nanoporous organic and hybrid aerogels for industrial applications: from the lab to pilot scale production)

Reporting period: 2018-11-01 to 2019-04-30

The main objective of NanoHybrids was the development of the first pilot-scale production system for a new generation of multifunctional nanoporous organic and hybrid aerogels with applications in gas adsorption, humidity control, consumer good and food.
Aerogels are the lightest solids existing today and are mainly used for the thermal insulation purposes. Therefore, the market is mainly limited by inorganic aerogels. However, other applications fields, primary life science applications require biocompatible aerogels.
In general, organic aerogels could have much broader application sprectrum, which is still not fully exploited, mainly because currently, organic or hybrid aerogels are not produced on an industrial or pilot scale. This limits significantly the further development of the organic aerogels and their transfer to the market. NanoHybrids has developed the means to scale-up organic and hybrid aerogels production from the laboratory to the pilot scale. The aerogels produced were tested in corresponding prototypes in industrial environments. Based on the test results from the prototypes, the chemical composition, physical properties and pore size distribution of the materials were adjusted for each given application. In order to reduce the processing time and manufacturing costs, the focus was made on the production of aerogel particles with desired particle size distribution. In order to optimize the process, especially the supercritical drying step, a special multi-scale model allowing to describe all the production steps is developed. The optimized conditions are realized in the pilot scale supercritical drying unit (> 500 L). More then 200 Liters of organic (alginate-based) aerogels in form of microparticles were produced.
Overall, new aerogel products and a cost efficient technology for their pilot scale production are established and protected by industrial partners. Based on these results a concept for the larger production scale was developed. For new aerogel applications, business cases/plans were presented. Finally, the Technology Readiness Level (TRL) of organic and hybrid aerogel production was increased from TRL 4 to TRL6/7. In conclusion, the project firstly enabled the production of organic aerogels in form of particles of different sizes, in quantities required for the tests in real industrial environment.
In this project the technologies for the production of aerogels in form of the beads and particles of the required size (10 µm-5 mm) were developed. Specially jet cutting and emulsion-gelation methods were confirmed as best suitable methods. Systematical study of both technologies was conducted and scale up to >100 Liters scale was realized. Further, semi-continuous methods were developed to improve the efficiency and to reduce the production costs. Subsequently, optimal process parameters for each aerogel type were identified. Using those large quantities of different aerogels (>100 L) were produced for their testing for food and adsorption applications in real industrial environments.
Firstly, aerogel particles were produced in food grade quality, allowing their testing for food applications in real industrial environments. Tests of the newly produced organic and hybrid aerogels for the adsorption of moisture and hazardous gases were performed. Mathematical modelling of the aerogel structure on the molecular level allowed for the first time to tune the aerogel properties for the specific applications. CFD simulations of the apparatus for the aerogel production allows to combine the modelling on the molecular level with the modelling of the appartus in general. Therefore, the multiscale modelling was realized for all steps of aerogel production process. Based on the models developed, further scale up of the aerogel production can be made.

Scale up of supercitical drying technology was performed as well. The experimental database gained within the project allowed to develop new correlations for quantative description of supercritical drying. Mathematical modelling of all processes involved in aerogel production was established. In summary, TRL of organic aerogel production was increased to TRL 6/7.

The results of the project were published in 16 papers, six PhD thesis, 31 oral presentations, 21 poster presentations, one bachelor thesis and four master thesis. The new aerogel products were presented in PowTech, the largest solid particulated matererials fair, in 2019. Several events open for the wide public (science nights, girls days) were used to present the aerogel technology and new aerogel products.
Aerogels are low-density, highly porous nanostructured solids. Aerogels were invented in the 1930s and are can be principally obtained by drying almost any kind of wet-gels under conditions that preserve their volume. These conditions usually involve converting and venting off the pore-filling solvent in form of supercritical fluid. The resulting aerogels possess very high mesoporous volume and specific surface area, what results in a very low density and thermal conductivities, high acoustic attenuation, and further spectacular properties. Aerogels being known as the lightest solid materials, have a tremendous potential in a wide range of applications, where high pore volume and high surface area play major roles.

In the last decades it was shown, that a number of different organic precursors (biopolymers) can be utilized to produce aerogels from sustainable sources and with specific functions that can be successfully used in different emerging areas.Since applications in adsorption (gas and humidity filters), personal care (cosmetics) and food additives do not require monoliths, but rather spherical particles (microparticles, granules) of specific size and controlled porosity, direct production of aerogels in such a form is decisive for opening these markets for organic aerogels.

In order to prove the real applicability of these new types of aerogels in industrial settings, significant amount of materials are needed for prototyping on pilot scale.Currently the manufacturing of organic aerogels is mainly restricted to monoliths. Production of aerogels in the form of particles is developed on the lab scale for some polysaccharide aerogels. In this project this technology is extended to other aerogel types and firstly transferred to the pilot scale.

NanoHybrids proved the technical and economic viability of nanoporous materials in the form of organic and hybrid aerogels. The results achieved show a high potential of aerogels and suggest new production's methods thereof, contributing to new applications and new markets for aerogels.

Construction and building (e.g. thermal insulation)
Transport, filtration and purification (e.g. mechanically resilient nanoporous filter systems)
Biomedicine (e.g. wound dressings, controlled release delivery systems, excipients)
Sensors (e.g. highly sensitive gas sensors)
Chromatography (e.g. supercritical chromatography)
Consumer goods and personal care (e.g. bio-based, biodegradable cosmetics additives)
Food technology (e.g. bio-based, biodegradable high-capacity aroma carriers)
Agriculture (e.g. biodegradable and high-capacity pesticide, herbicide or fungicide controlled release systems)
Aerogel beads
Poster NanoHybrids
Production of aerogel beads by jet cutting (picture by DLR)
NanoHybrids logo
NanoHybrids consortium (picture by TUTECH)