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Permeability of powder beds formed from spray dried dairy powders in relation to morphology data

Börjesson, Erik LU ; Innings, Fredrik LU ; Trägårdh, Christian LU ; Bergenståhl, Björn LU and Paulsson, Marie LU (2016) In Powder Technology 298. p.9-20
Abstract

The formation of lumps during industrial recombination of powder is a common problem in many industries. An important step in the recombination process is the wetting of the dry material. Only with an efficient wetting the individual powder particles will disperse and a complete dissolution will occur. In difference, a slow or incomplete wetting will not supply liquid to all portions of the powder, resulting in the formation of lumps.The resistance to wetting can be described by a material's permeability. This parameter is often estimated using the Kozeny-Carman equation, which models the permeability of a porous medium (such as a bed of powder) based on the porosity and specific surface area of the medium. This model has proven valid... (More)

The formation of lumps during industrial recombination of powder is a common problem in many industries. An important step in the recombination process is the wetting of the dry material. Only with an efficient wetting the individual powder particles will disperse and a complete dissolution will occur. In difference, a slow or incomplete wetting will not supply liquid to all portions of the powder, resulting in the formation of lumps.The resistance to wetting can be described by a material's permeability. This parameter is often estimated using the Kozeny-Carman equation, which models the permeability of a porous medium (such as a bed of powder) based on the porosity and specific surface area of the medium. This model has proven valid for a bed of packed spheres, but due to the model assumptions the accuracy of the model when utilized on beds formed from more complex, spray dried powders can be questioned.In this study, the permeability of powder beds consisting of spray-dried diary powders when exposed to an air flux has been characterized, using a method based on air permeametry. The results show that the Kozeny-Carman model is insufficient to estimate the permeability of such beds. Furthermore, the measured porosity of the bed had no influence on the permeability constant.Based on the results of this study a correlation between morphological powder parameters and permeability was developed. This correlation indicates that a small surface weighted average diameter of the particles as well as a narrow width of the particle size distribution have a positive effect on the permeability of a bed. In addition, incorporation of the structural parameter "BedRatio", defining the basis of the bed to consist of agglomerates or primary particles (fines), indicates that a bed consisting of mainly agglomerates has a slightly larger permeability.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Kozeny-Carman, Permeability, Permeametry, Porosity, Porous media, Powder bed
in
Powder Technology
volume
298
pages
12 pages
publisher
Elsevier
external identifiers
  • Scopus:84969703273
  • WOS:000378953100002
ISSN
0032-5910
DOI
10.1016/j.powtec.2016.05.006
language
English
LU publication?
yes
id
d9e4fcb2-7ad1-4ccb-b321-627d544db3fe
date added to LUP
2016-07-18 15:01:13
date last changed
2017-02-05 04:51:47
@article{d9e4fcb2-7ad1-4ccb-b321-627d544db3fe,
  abstract     = {<p>The formation of lumps during industrial recombination of powder is a common problem in many industries. An important step in the recombination process is the wetting of the dry material. Only with an efficient wetting the individual powder particles will disperse and a complete dissolution will occur. In difference, a slow or incomplete wetting will not supply liquid to all portions of the powder, resulting in the formation of lumps.The resistance to wetting can be described by a material's permeability. This parameter is often estimated using the Kozeny-Carman equation, which models the permeability of a porous medium (such as a bed of powder) based on the porosity and specific surface area of the medium. This model has proven valid for a bed of packed spheres, but due to the model assumptions the accuracy of the model when utilized on beds formed from more complex, spray dried powders can be questioned.In this study, the permeability of powder beds consisting of spray-dried diary powders when exposed to an air flux has been characterized, using a method based on air permeametry. The results show that the Kozeny-Carman model is insufficient to estimate the permeability of such beds. Furthermore, the measured porosity of the bed had no influence on the permeability constant.Based on the results of this study a correlation between morphological powder parameters and permeability was developed. This correlation indicates that a small surface weighted average diameter of the particles as well as a narrow width of the particle size distribution have a positive effect on the permeability of a bed. In addition, incorporation of the structural parameter "BedRatio", defining the basis of the bed to consist of agglomerates or primary particles (fines), indicates that a bed consisting of mainly agglomerates has a slightly larger permeability.</p>},
  author       = {Börjesson, Erik and Innings, Fredrik and Trägårdh, Christian and Bergenståhl, Björn and Paulsson, Marie},
  issn         = {0032-5910},
  keyword      = {Kozeny-Carman,Permeability,Permeametry,Porosity,Porous media,Powder bed},
  language     = {eng},
  month        = {09},
  pages        = {9--20},
  publisher    = {Elsevier},
  series       = {Powder Technology},
  title        = {Permeability of powder beds formed from spray dried dairy powders in relation to morphology data},
  url          = {http://dx.doi.org/10.1016/j.powtec.2016.05.006},
  volume       = {298},
  year         = {2016},
}