Doctoral Defense Clara Lauscher
A new atomization process was developed to overcome the limitations of conventional atomizers in regard to the production of droplets in the small micrometer size range. These droplets can further be dried, resulting in submicron particles.
The process includes the preparation of a high-pressure emulsion of an aqueous solution and liquid carbon dioxide, which is expanded through an orifice nozzle with a small length-to-diameter ratio in a subsequent step.
The droplet diameters in the emulsion were determined at values between 244 and 728 µm. Due to the expansion of the liquid carbon dioxide, the droplet diameters were disintegrated by a factor of up to 140. The disintegration factor was mainly influenced by the ratio of the mass of the aqueous phase to the mass of the liquid carbon dioxide in the emulsion. After drying the droplets, a further size reduction could be seen resulting in particles between 0.4 and 3.1 µm.