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Faculty of Mechanical Engineering
Institute of Process Engineering and Environmental Technology
Research Group Mechanical Process Engineering
Dipl.-Ing. Lars Hillemann, PD Dr.-Ing. Michael Stintz
TU Dresden, Inst. of Process Engineering and Environmental Technology
Research Group Mechanical Process Engineering, D-01062 Dresden
Phone: +49 351 463 32914 Fax: +49 351 463 37058
Email: lars.hillemann@tu-dresden.de
Web:
http://www.mvt-tu-dresden.de
Dr. Mario Heinemann
Wacker-Chemie AG, Werk Burghausen
D-84480 Burghausen
Phone: +49 8677 83 4022 Fax: +49 8677 83 6814
Email: mario.heinemann@wacker.com
Web:
http://www.wacker.com
Quantification of nanoparticle releases
Lars Hillemann
1
, Michael Stintz
1
, Mario Heinemann
2
1 Institute of Process Engineering and Environmental Technology, TU Dresden, D-01062 Dresden, Germany
2 Wacker-Chemie AG, Werk Burghausen, Johannes-Hess-Str. 24, D-84480 Burghausen, Germany
Measuring method – demands and solutions
Maximum dispersing from powders
Practical relevant dispersing from powders
Motivation and Challenges
[1]
Aerosol technology, W. C. Hinds, Wiley 1999.
[2]
Reinraumtechnik, L. Gail, H. Hortig, Springer-Verlag 2002
The fraction of particle
matter deposited in the lung
depends on particle size [1].
• ensure nanoparticle application
• safeguard health protection
• avoid environmental pollution
• reasonable
release energy
• reasonable weighting
of particle size fractions
• accessible results
• Dispersing shear stress
typical for usage
• Counting the number of released
particles of a size range (nano-
particles, submicron particles)
• relate this number to the applied
sample mass (=release rate)
• Conversion into the concentration
of a model-room
model-room concentration:
Experimental setup for maximal dispersing
(“Worst case”)
RBG ... Rotating-brush-generator
SMPS ... Scanning mobility particle sizer
CPC ... Condensation particle counter
The number of releasable particles per sample mass depends on the dispersing intensity
applied on the sample. To underline this, two different dispersing methods have been
compared.
The concentration in the mixing
chamber was measured by SMPS
and CPC. From this results the
number of particles < 100 nm was
calculated and related to the sample
mass.
This gives the
release rate
of
particles.
As a example for the practical handling of particle systems in industrial processes light
bagging and conveying a sieving machine was used to disperse the sample.
Experimental setup
for practical relevant
dispersing using
a sieving machine
The sieving machine was an
example for typical handling.
The number concentration
was recorded by two CPCs.
One of this devices was
equipped with a diffusion
battery to distinguish
between particles smaller and
bigger than 100 nm.
To interpret the release rate, the
number concentration in a model-
room
(10 m2 floor area, 3 m high)
was estimated if 100g of the
sample would be dispersed [2].
release rate
model-room
concentration
release rate:
technical data
nozzle diameter
5 mm
flow velocity
14,1 m/s
sample size
150 x 150 mm
sample feed rate
1 – 6 mm/s
Practical relevant release from surfaces
Release rate of particles
determined by two CPCs,
one equipped with a
diffusion battery.
From the differences between the number
concentration of both particle counters the
release rate of particles < 100 nm can be
calculated.
Test rig
Results
The objective of the experimental investigations was to quantify the release
of particles from fabrics coated with particle layers. A test rig was developed,
consisting of a sample carrier and a shiftable nozzle.
Under the nozzle, a
sample can be moved
in two directions.
The diameter of the nozzle is larger than the
dimension of the fiber under consideration but small
enough to reach high shear stresses at low flow rates.