To obtain a reproducible and specification conforming product quality it is mandatory to control the process parameters for granulation and layering or coating. One important parameter for the development of coating and granulation processes in high shear and fluid bed processes is the spraying system [1] e. g. the application of a feasible droplet size coming out of the respective spraying nozzle. Too large droplets could result in oversized granules or in pellets´ agglomeration, whereas too small droplets could lead to spray drying, dust, reduced yields or assay values or deviating dissolution results.In contrast to other process parameters like inlet air volume or spray rate the droplet size cannot be directly controlled but is mainly resulting from the applied atomization air pressure [2] as well as from spray rate, nozzle [2, 3] and formulation of the spraying liquid.In the present study the influence of the polymer content i. e. the viscosity of the spraying liquid on the droplet size distributions for atomized spraying liquids was statistically evaluated at different atomization air pressures and spray rates.

CONCLUSION

Droplet size distributions of aqueous PVP solutions were measured applying the laser diffraction technology. Droplet sizes increase with higher spray rates and lower atomization air pressures, in the same time broader droplet size distributions were measured.

With increasing polymer content (higher viscosity) in the spraying liquid, larger droplets are obtained. To receive the same droplet size while increasing the polymer content would result in lowering the spray rate or increasing the atomization air pressure.

Interested to get more Information? Get in touch with us!

Poster @ PBP Worldmeeting in Granada 2018