1. Novica S. Rados - graduate student -
B.S. in Chemical And Polymer Engineering
University of Belgrade
M.S. in Chemical Reaction Engineering
D.Sc. in Chemical Reaction Engineering
Washington University, St. Louis
Research Engineer
Perstorp, Sweden and DUGA, Yugoslavia
Good morning Ladies and Gentleman.
My name is Novica Rados and I am completing my D.Sc. at CREL.
I received my BS in ChE from the University of Belgrade in Serbia in I worked for some time in Perstorp Co. in Sweden. Then I went back to Belgrade where I joined DUGA Co. and simultaneously studied towards the MS degree. I transferred to Washington University in 1996 where I joined CREL. During the course of my study I have been working on the improvement of our understanding of SBC hydrodynamics. Especially, at industrially relevant operating conditions - high SGV and pressure.
I am presently writing my thesis and expecting to graduate sometime in early 2002.

2. Advancements in the CARPT Technique - First Poster -
HP Slurry Bubble Column Consortium
US,z
z/L
US,z
r/R
CARPT
solids
axial velocity
How to conduct a CARPT experiment in
the high pressure slurry bubble column ?
Some of the addressed issues are:
high SS g-radiation attenuation
closed system --> difficult calibration
protection of the tracer particle in H2O & air
- etc.
solid
angle
G-L-S
medium
Slurry bubble column (SBC) is a cylindrical vessel in which gas is bubbled through the suspension of liquid and solid particles. To improve our understanding of SBC experimental data on velocity and holdup distributions are needed. Especially at the high pressure and SGV industrially used operating conditions.
CARPT is a one of a few techniques that can provide the information on velocity and turbulent parameters (TKE) profiles in opaque systems such is a SBC. At CREL we have used CARPT in both G-L and slurry systems for years but at atmospheric pressure and low SGV. The challenge that we faced in this study conducted for the HP SBC consortium was how to conduct a CARPT experiment in HP SBC?
The problems that we faced were:
- High SS g-radiation attenuation, consequently a large photon scattering that we observed using the existent data acquisition method and large attenuation gradients caused by the presence of SS wall and solid particles
At HP a SBC is a closed system to the atmosphere. How to do the in-situ calibration of the CARPT experiment. I.e, how to move the tracer particle from one to the other known location within the operational closed column.
Tracer particle is a Sc mm particle. Scandium reacts with both air (gas phase) and water (liquid phase). How to protect such a tiny particle against oxidation and eventually contamination of the system. Etc. Etc.
wall path
detector
crystal G
CHEMICAL REACTION ENGINEERING LABORATORY

3. Results  Performance of the FT slurry bubble column
Modeling of the FT Slurry Bubble Column Reactors
- Second Poster - L SB LB
Develop a dynamic model for the reacting slurry systems with a change in gas flow rate due to the chemical reaction and use it to model the FT slurry bubble column.
steady state profiles
Convective Flux
FT synthesis has always been an alternative to oil refining.
In this study we wanted to develop a dynamic model for simulation of the (general) reacting slurry system with a change in gas flow rate due to the chemical reaction, test it and than use it to model the FT SBC reactor.
The basis of our model is a two bubble class model. Change in SGV was calculated using the overall gas mass balance. All three phases are modeled using the ADM model. Between the G and L phase mass transfer is accounted while between the SB and the LB bubble-bubble interaction is considered via a cross flow bubble mixing.
In this poster I present the developed model, some test results of general SBC modeling and then the obtained dynamic and steady state profiles for different operating conditions and reactor dimensions. I am critically addressing the effect of different parameters on the performance of the FT SBC reactor. Finally, I make a comparison between developed ADM model and simplified representation of the back-mixing in different phases using the ideal reactor models (PFR and CSTR).
If you are interested in this please come to discuss it further with me.
Thank you for your attention.
Bubble Mixing
Axial Dispersion
Results  Performance of
the FT slurry bubble column
Mass Transfer

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