Project Details
Projekt
Particle generation by spraying of gas containing polymer melts and polymer solutions
Applicant
Professor Dr.-Ing. Marcus Petermann
Subject Area
Mechanical Process Engineering
Term
from 2011 to 2014
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 198248311
During this project the formation of particles by high pressure spray processes shall be investigated. Due to an increasing request of functional particles and powders by food-, cosmetics- and health industries the mechanisms during the formation of those particles should be understood. The functionality of powders is basically influenced by the particle size and the morphology. Till today the particle formation of high viscous polymer melts and solutions in spray processes with supercritical fluids is not completely understood. In this project gas assisted high pressure sprays shall be observed by optical measurement techniques as by Particle-Image-Velocimetry (PIV) and by a high-speed camera. By using those techniques the boundary conditions concerning heat- and mass- transfer can be determined in order to develop a numerical model based on physical properties of the sprayed substance. The substances which are used are Polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP). The process, investigated in this proposal is the so called PGSS-Process (Particles from gas saturated solutions). Thereby a compressed gas is dissolved in the polymer melt under high pressure. Passing a nozzle, the compressed and dissolved gas expands and increases its volume due to the extreme pressure drop downstream the nozzle. The expansion of the gas leads to an intense disintegration of the spray and the formation of small droplets. The decrease of the temperature by the Joule-Thompson Effect leads to a rapid cooling and an accelerated solidification of the melt. With this process particle sizes in a range of 5-300 µm can be achieved and easily separated from the gas flow by common separation techniques.
DFG Programme
Priority Programmes
Participating Person
Dr. Sabine Kareth
