Kinetics and Engineering
2003 Annual Seminar
Welcome to the 2003 annual seminar on Mathematics in Chemical Kinetics
and Engineering, to be held at Ghent University, Belgium on April
The Laboratory for Petrochemical Technology (LPT) and
the Research Group for Numerical functional analysis and Mathematical
Modelling (NfaM2) of
Ghent University are pleased to invite you to attend the annual seminar
on "Mathematics in Chemical Kinetics and Engineering" which will be
held on April 25th, 2003 in Ghent, Belgium.
After the successful
international Mackie-2002 conference held last year at Ghent University,
the local organizers have now invited two world-class experts from the
fields of mathematics and chemical engineering, Prof. Gerhart Eigenberger
(Stuttgart Univ.) and Prof. Vladimir Gol'dshtein (Ben-Gurion Univ.) to
give seminar talks during a one-day mini-symposium.
to the seminar is free, but registration is requested AS SOON AS POSSIBLE.
Lunch is available at the venue (15 euro).
- 10:00 Coffee and registration
- 10:45 Introduction
- 11:00 Gerhart Eigenberger on Pattern formation in fixed-bed
reaction and separation processes - Analysis and application
- 12:00 Question time and discussion
- 12:30 Lunch
- 14:30 Vladimir Gol'dshtein on Multiscale analysis of multiphase
- 15:30 Question time and discussion
- 16:00 Concluding remarks and closing address
- "Pattern formation in fixed-bed
reaction and separation processes --- Analysis and application",
by Gerhart Eigenberger and Grigorios Kolios, Institut für Chemische
Verfahrenstechnik, Universität Stuttgart, Germany.
patterns in fixed-bed processes are self-sharpening or dispersive
reaction and/or adsorption fronts. They play an important role in Chemical
Engineering processes. In this contribution we will present an overview
about the origin and the basic characteristics of the different fronts
and discuss the influence on the behavior of the reaction and separation
processes in which they occur.
We will distinguish between simple
temperature fronts (heat waves) and reaction fronts of fluid reactions for
endothermic reactions and for exothermic with and without deactivation. A
second class comprises of reaction fronts in which a part of the solid
fixed-bed participates in form of a fluid-solid reaction. Typical
examples are coke combustion from catalyst beds or soot combustion from
Diesel particulate filters. Compared to exothermic reaction fronts for
fluid reactions the behavior is further influenced by the availability
and consumption of the solid reactant.
The third class of fronts
are adsorption/desorption fronts which tend to be self-sharpening or
dispersive depending upon the curvature of the adsorption isotherm or
the volume fraction of adsorbable component in the feed.
or sorption fronts have found their most interesting applications
in periodi-cally operated fixed-bed processes which cycle between a
storage and regeneration phase. If this cycling is combined with a
periodic reversal of flow direction, an additional positive feedback
is introduced which can substantially influence process dynamics and
stability. Examples are fixed-bed reactors with periodic flow reversal
and pressure swing adsorption processes for gas phase separations which
will be presented in some detail.
The parametric sensitivity and
stability analysis of cyclic, spatially extended systems is so far not
very well developed. For high cycling frequency an analogy with co- or
countercurrent membrane processes can be used. For larger cycle periods,
characteristic of most engineering applications, efficient methods for the
direct calculation of the cyclic steady state will be required. We will
discuss some novel developments in this area.
- "Multiscale analysis
of multiphase combustion", by Igor Goldfarb and Vladimir Gol'dshtein,
Department of Mathematics Ben-Gurion University of the Negev, Israel.
Multiphase combustion is a widespread phenomenon in industry (sprays
in Diesel engines, spontaneous insulation fires in chemical plants, flame
propagation in porous media, etc). Physico-chemical processes of different
nature with sufficiently different time scales are generally involved
in multiphase combustion processes. Existence of an essential dispersion
of time scales leads to multiscale systems of governing equations (more
formally, singularly perturbed systems of differential equations).
The hierarchical structure of mathematical models allows to apply various
asymptotic approaches for analysis of systems dynamics. We suggested to
use a geometrical asymptotic method of invariant (integral) manifolds
(MIM) adapted to combustion and chemical kinetics problems. MIM permits to
conduct an analytical investigation of the multiphase combustion models,
allows to describe qualitatively systems dynamics and to gain estimations
of key parameters. This geometrical interpretation of multi-scale
hierarchy of systems dynamics permits to decompose an original high
dimensional problem to a few separate problems of essentially lower
dimension on invariant (integral) manifolds.
We will discuss
two main types of problems: thermal runaway and flame propagation
in sprays. The obtained results are relevant to modeling of Diesel
engines and hazardous flames formation and propagation in insulation
materials. One of distinguishing features of the multiphase combustion
is existence of comparatively long-time delay before finale blow-up due
to competition between the exothermic chemical reaction and heat sink to
the liquid and/or solid phase. Typical examples are self-ignition delay in
Diesel engines and long-time self-ignition delays in insulation materials.
Thermal runaway. This phenomenon is modelled using the spatially
uniform approach. The typical parametric classification of the dynamical
behavior includes conventional (?fast?) thermal runaway and the mainly
interesting phenomenon of delayed self-ignition. Estimations for the
delay time are derived for the typical sprays and porous media. The
relevant estimates for simplified models of Diesel engines have
good agreement with appropriate numerical simulations.
driven flames. Traditionally the study of the premixed gas flames in an
open space ignores the pressure perturbations. It means that pressure
disturbances come away from the reaction zone and do not influence on
the intensity of the thermal processes. In this research we deal with a
gas phase combustion in inert porous media. The distinguishing feature of
inert porous media is the well-known fact that under definite conditions
the speed of pressure perturbations may be significantly lower than sound
velocity in the open space. In these conditions the local elevation of the
pressure may lead to a formation of the self-sustaining combustion wave
controlled by pressure diffusion (rather than the conventional thermal
diffusion) We will discuss an original model proposed for description
of the phenomenon and a special asymptotic approach (based on MIM)
which allow us to study a fine structure of flame front and the the
flame velocity dependence on barodiffusion.
The annual seminar on Mathematics in Chemical Kinetics and Engineering
will be held in the Pand, a renovated ancient building owned by Ghent
University, and situated in the heart of Ghent's historical centre
(address: Onderbergen 1).
Tourist Attractions in Ghent
Belgium possesses a wealth of highly distinctive architectural, cultural
and gastronomic traditions.
Ghent, founded in the 10th century AD,
has today a population of over 200 thousand. The official language is
Dutch; knowledge of English is very widespread.
attractions include the Gothic Cathedral and other medieval churches,
the Van Eyck Altarpiece depicting the Adoration of the Mystic Lamb,
the City Museum of Contemporary Art (SMAK), and numerous shops selling
Flemish specialities such as local beers, lace and many other renowned
products of authentic handicraft.
April is early Spring in Ghent, with average temperature of
12 degrees Celsius. Some rain is to be expected.
register by sending e-mail to email@example.com. Please also
state if you want lunch at the venue (cost: 15 euro).
latest information, consult the annual seminar's Web site at www.mackie-workshops.com
Denis Constales - firstname.lastname@example.org - http://cage.UGent.be/~dc/index-world.html