Folie 1

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Study ofSuperheated Steam Granulation in
Fluidized Beds
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Personal data
André Sommer born at 20th of may 1981 in
Aschersleben (SA) near Magdeburg
(Germany) 2000-2006 study of power
mangement 2006 Diploma thesis at Inst. of
Process Equipment and Environmental Technology,
Faculty for Process and Systems Engineering

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Topic of research
Study of Superheated Steam Granulation in
Fluidized Beds
Supervisor Jun.-Prof. Dr.-Ing. Stefan Heinrich
Co-Supervisor Prof. Dr.-Ing. habil. Evangelos
Tsotsas Inst. of Process Equipment and
Environmental Technology, Faculty of Process and
Systems Engineering
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nozzle
solvent
nuclei
fluidized bed
fluidization gas
growth of a particle
fluidized bed apparatus
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Advantages of steam drying/granulation
processes Energy saving potential, when the
steam is circulated Increase of plant safety
due to inert steam atmosphere (exclusion of
oxygen) Disadvantages of steam
drying/granulation processes Higher investment
costs for plant technology(isolation, heating of
apparatus walls) Applicable only for thermally
stable products
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Research objektives and future intentions
Simulated and experimental evaluation of
advantages/disadvatages of superheated steam
granulation concerning heat and mass transfer

• Batch and continuous granulation experiments by
  variation of
• nuclei material
• monodisperse and polydisperse bed
• nuclei diameter of monodisperse bed

Improvement of the available model of heat and
mass transfer of superheated steam granulation in
fluidized beds (Robert Hampel)
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Available experimental set-up

• Operation with steam and air possible
• Batch and continuous processing
• Measuring system
• Condensation of steam and recovery of fines
• Max. steam mass flow 550 kg/h
• Max. steam inlet temperature 300 C
• Cylindrical fluidization chamber 250 mm diameter

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Thanks for your attention
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Study ofSuperheated Steam Granulation in
Fluidized Beds
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Modelling of heat and mass transferModel
assumptions
Balance scheme

• Model conditions
• Continuum model (1D)
• homogenous fluidization (e constant)
• ideal mixing of particles (CSTR)
• plug flow of the gas phase (PFTR)
• neglect of particle temperature profile
• constant spatial wall temperature
• liquid is deposited on theparticle surface as a
  filmwith constant thickness

with
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Modelling of heat and mass transferModel
equations
Gas phase Energy balance of the gas
Liquid phase Energy balance of the liquid
Gnielinski
Gnielinski
Martin
Reppmann
Mass balance of the liquid
Mass balance of the gas
Degreeof wetting
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Modelling of heat and mass transferModel
equations
Solid phase Energy balance of the particles
Energy balance of the wall
Churchill Chu
Martin
Evaporation Flow rate of evaporated water
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Modelling of heat and mass transferMeasurement
vs. simulation of steam outlet temperature
.
.
Ml,in 5 kg/h
Ml,in 20 kg/h
?-Al2O3-particles
?-Al2O3- particles
Porous material
Glass beads
Glass beads
Non-porous material