Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
On the optimization of the fluidized bed particulate coating process
KTH, Superseded Departments, Chemical Engineering and Technology.
1998 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

Different aspects that influence the fluidked bedparticulate coating process have been investigated. An easy touse procedure for creating temperature and humidity profilesfor the gas inside the bed was developed. The procedureinvolves measuring a limited number of points inside the bedand using these points generate more data points used for thecreation of the profiles. The profiles revealed that differentparts of the bed have a different involvement in the coatingprocess. Apart from showing the hydrodynamic conditions insidethe bed, the profiles can be used to optimize the size of thebed, to map the net migration of particles and to set thespraying rate limits.

The three-domain representation of the bed was used to modelthe coating process. The model showed that large beds and theexistence of stagnant region within the bed widen the toatingdistribution. Increasing the rate of transfer to the sprayingdomain or increasing the overall mixing of the bed Will havethe opposite effect of narrowing the coating distribution. Theunequal transfer between domains can be used to manipulate thetoating distribution. The combination of bed ske, differentrates of transfer between domains, size of spraying domain andthe rate of spraying can be used to obtain particles that arecoated to a particular distribution.The mechanism and kinetics of growth in a top sprayingprocess were determined by coating two poly-distributed seedparticles with a cellulose under different operatingconditions. The resulting particle distribution reveals thatnot all particles in the bed are equally coated. For the topspraying process, smaller particles Capture more toating thanlarger particles. A narrowing of the seed distribution wasfound to increase the chance of toating the large particles.The results also confirmed that particles are coated only aftervisiting the spraying region, which is small compared to therest of the bed. A growth model developed using theexperimental results introduces a segregation factor whichrepresent the probability of different particle sizes beingcoated. For the top spraying coating of lactose particle with acellulose, the segregation factor was found to be anexponential decaying function of the particle weight.

Keywords:granulation, coating, surface layering,segregation, coating uniformity, temperature protile, humidityprofile, growth kinetics, particle coating.

Place, publisher, year, edition, pages
Stockholm: Kemiteknik , 1998. , 69 p.
Series
Trita-KET, ISSN 1104-3466 ; 97
Identifiers
URN: urn:nbn:se:kth:diva-2720ISBN: 99-2807643-X OAI: oai:DiVA.org:kth-2720DiVA: diva2:8429
Public defence
1998-12-02
Note
NR 20140805Available from: 2000-01-01 Created: 2000-01-01Bibliographically approved

Open Access in DiVA

fulltext(557 kB)9644 downloads
File information
File name FULLTEXT01.pdfFile size 557 kBChecksum MD5
9fe49ebe2e98d369aecc0448f6f5f9b89f85fa939de8473f80387ee00d7e3aa61be10ea0
Type fulltextMimetype application/pdf

By organisation
Chemical Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 9644 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 640 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf