Fluidized bed combined with RESS process in supercritical carbon dioxide (SC-CO2) is a promising technology
for coating heat-sensitive materials of high added value. This work presents a study of the most
influencing operation parameters (temperature, pressure and flow) of the two steps of the process (saturation
and coating).
As a model system, glass beads particles (dp,s =176m)were encapsulated with paraffin (Tm = 52–54 ◦C).
Two different ways of injecting the coating solution of paraffin in the SC-CO2 in the fluidized bed were
tested, bottomand top spray. The operation variables were kept in the following ranges for the saturation
step: pressure from 18 to 22MPa and temperature from 35 to 55 ◦C. In the coating process the pressure
range from 8 to 10MPa and temperature from 35 to 50 ◦C. Yields of the global process up to 70% were
achieved. SEM-images of the achieved coatings show complete coating films with no agglomeration in
the top spray experiments.