Drying of polymer powder in fluidized bed. Modelling of multizone dryer/Susenje polimernog praha u fluidizovanom sloju. Modeliranje viseslojne susnice

• Published in: Hemijska industrija Vol. 68; no. 6; p. 661
• Main Author: Ostrovskii, Nickolay M
• Format: Journal Article
• Language: English
• Published: Association of Chemical Engineers of Serbia 01.11.2014
• Subjects: Drying; Methods; Polypropylene; Powders
• ISSN: 0367-598X
• DOI: 10.2298/HEMIND131016007O

The process of drying of porous polymer powder (polypropylene) intended to remove the solvent (heptane) is analyzed. The dryer consists of two stages (apparatus) with multizone fluidized bed. The mathematical model of the process in multizone fluidized bed is proposed. The rate-limiting step, depending on diameter of polymer particles, is determined. It was found that in relatively large particles (>200 µm) the rate of drying is limited by intraparticle diffusion. A way to decrease the energy consumption in drying has been also discussed and verified in experiments. Keywords: polymer powder drying, fluidized bed, rate limiting step, multizone dryer, mathematical model. Analiziran je proces susenja poroznih cestica polimera (polipropilena) sa ciljem uklanjanja rastvaraca (heptana). Susnica ukljucuje dva stadijuma (aparata) sa fluidizovanim slojem u kojima postoje nekoliko zona susenja. Predlozen je matematicki model procesa u fluidizovanom sloju sa razlicitim zonama. Odreden je limitirajuci stupanj susenja u zavisnosti od precnika polimernih cestica. Pronadeno je da u relativno krupnim cesticama (>200 µm) brzina susenja se limitira difuzijom unutar cestica. U malim cesticama (<50 µm) proces limitira prenos mase kroz spoljasnu povrsinu mehurica gasnog fluida (azota). Model je pokazao zadovoljavajucu saglasnost sa eksperimentalnim podacima i koriscen je za optimizaciju rada susnice. Data je analiza nacina smanjenja potrosnje energije koje su ispitane u eksperimentima na industrijskom postrojenju. Kljucne reci: Susenje polimernog praha * Fluidizovani sloj * Limitirajuci stupanj * Zone susenja * Matematicki model Available online at the Journal website: