Novel supercritical fluid processing techniques for the production of an aerosol

The drying process is a crucial step in the production of a dry, dispersible powder. Many different areas of industry are affected by the state of powder dispersion from those that use it as raw materials to those for whom it is the final product. In order to improve the production of such powders, a number of available drying methods were further investigated to better understand the effect of the drying process on powder re-dispersion and determine the best drying method for this application. The drying methods under investigation included evaporation as a baseline, freeze drying, supercritical fluid processing (SCF), and a novel CO2 sublimation method. Drying time and production yields were taken into consideration. The results show that for all powders tested, SCF processing and CO2 sublimation produce, by far, the most dispersible powder.

Graphical abstractThe drying process is a crucial step in the production of a dry, dispersible powder. This investigation compares the dispersability of high aspect ratio powders, dried from alcohol by evaporation, freeze drying, supercritical drying and a novel CO2 drying method. The degree of dispersability was evaluated by infrared obscurance with supercritically dried powders demonstrating optimum dispersion.Figure optionsDownload full-size imageDownload as PowerPoint slide