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Simulation of HDS Tests in Trickle-Bed Reactor
V. Tukač
1
, A. Prokešová
1
, J. Hanika
1
, M. Zbuzek
2
and R. Černý
2
1
Institute of Chemical Technology, Prague, Technická 5, CZ-16628 Prague, Czech Rebublic
2
Research and education centre UniCRE Litvínov, CZ-43670 Litvínov, Czech Rebublic
Keywords: Hydrodesulfurization Simulation, Catalyst Tests, Trickle-Bed Reactor.
Abstract: The paper deals with methodology of simulation study devoted to evaluation of reliability of HDS catalyst
testing procedure in pilot three phase fixed bed reactor. Hydrodynamic behaviour of test reactor was
determined by residence time distribution method. Residence time and Peclet number of axial dispersion of
liquid phase were obtained by nonlinear regression of experimental data. Hydrodesulfurization reaction
kinetics was evaluated by analysis of concentration data measured in high pressure trickle-bed reactor and
autoclave. Simulation of reaction courses were carried out both by pseudohomogeneous model of ODE in
Matlab and heterogeneous reactor model of PDE solved by COMSOL Multiphysics. Final results confirm
presumption of eliminating influence of hydrodynamics on reaction kinetic results by dilution of catalyst
bed by inert fine particles.
1 INTRODUCTION
Sustainable development demands ultra-low
concentrations of sulfur and nitrogen compounds in
produced engine fuels – gasoline and diesel. Present
sulfur content valid in EU 10 ppm represents less
than one thousands of sulfur content of original
crude oil. Deep hydrodesulfurization (HDS) of
engine fuels is dominantly carried out in catalytic
trickle-bed reactors. Also testing of catalysts
affectivity and life cycle needs expensive long time
experimentation in pilot scale reactors to evaluate
catalyst decay and activity loses. Pilot trickle-bed
reactor for catalyst tests needs to produce reliable
results not affected by mass and heat resistance. To
avoid occurrence of temperature gradients, poor
catalyst wetting and fluid maldistribution a dilution
of bed of industry scale catalyst particles by fine
inert grains is used (Bej et al., 2001). In
contradiction to full scale reactors this dilution
changes interfacial area in the bed and affects
namely external mass transfer of hydrogen (Tukač et
al., 2007). Also hydrodynamics, pressure drop, gas
and liquid holdups and fluid axial dispersion seems
to be quite different (Mary et al., 2009).
The goal of this study was to compare
experimental HDS catalyst activity measurement
carried out in pilot scale trickle-bed reactor with
result of computational model. Catalyst activity tests
were supplemented by kinetic measurement of
reaction rate constants and activation energies of
selected sulfuric compounds. Parallel to HDS
reaction also hydrodenitrogenation (HDN) takes
place in the catalytic reactor. Hydrodynamic data
were evaluated by residence time distribution (RTD)
method in laboratory glass model of pilot reactor.
Mathematical models of the process (Ancheyta,
2011) were formulated both like 1D
pseudohomogeneous and 3D heterogeneous ones.
The aim of this work was generally to evaluate
extent of dilution influence on operation of pilot test
reactor and to forecast interaction between intrinsic
reaction kinetic, hydrodynamic parameters and mass
transfer.
2 EXPERIMENTAL
Pilot catalyst activity tests were carried out in high
pressure trickle-bed reactor of 30 mm I.D and 887
mm length. In the axis of the reactor 9 mm O.D.
temperature probe was located. Reactor bed consists
of three section of different porosity, from the top to
the bottom: 765 mm calming section of 1-2 mm
grain inert, which was followed by two section (110
and 172 mm) of commercial catalyst diluted by
different amount (2:1 and 1:1, resp.) of inert.
Catalyst particles were in form of trilobe alumina
739
Tuka
ˇ
c V., Prokešová A., Hanika J., Zbuzek M. and
ˇ
Cerný R..
Simulation of HDS Tests in Trickle-Bed Reactor.
DOI: 10.5220/0005090807390744
In Proceedings of the 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH-2014),
pages 739-744
ISBN: 978-989-758-038-3
Copyright
c
2014 SCITEPRESS (Science and Technology Publications, Lda.)