Mathematics in Chemical
Kinetics and Engineering

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 28th, 2004 in Ghent, Belgium.

After the successful international Mackie-2002 conference and Mackie-2003 Annual Seminar held at Ghent University, the local organizers have again invited two world-class experts from the fields of mathematics and chemical engineering, Prof. Pierre Rouchon (École des Mines de Paris) and Prof. S. Pushpavanam (I.I.T Madras), to give seminar talks during a one-day mini-symposium.

Participation to the seminar is free, but registration is requested AS SOON AS POSSIBLE (simply register by sending e-mail to dcons@world.std.com). A complimentary lunch is offered to the participants at the venue.

Program

• 10:00 Coffee and registration
• 10:45 Introduction
• 11:00 Pierre Rouchon on Invariant estimation and control of a polymerization reactor
• 12:00 Question time and discussion
• 12:30 Lunch
• 14:30 S. Pushpavanam on Modeling and Simulation of Coupled Non-Linear Systems
• 15:30 Question time and discussion
• 16:00 Concluding remarks and closing address

Organizing Committee

• Denis Constales (NfaM2)
• Geraldine Heynderickx (LPT)
• Guy Marin (LPT)
• Roger Van Keer (NfaM2)

Abstracts

• "Invariant estimation and control of a polymerization reactor" by Pierre Rouchon and Nasradine Aghannan, of the Centre Automatique et Systèmes, École des Mines de Paris, France.
  The industrial project concerns the reactor PP2 (polypropylene) on the petrochemical plant of Feluy (Belgium). The objectives consist in increasing the productivity while maintaining a better stability for the polymer quality. In this order, we have developed new regulators to control better the principal variables defining the reactors content, which are at the heart of these production plants. First, our task was to establish a model to represent the reactors dynamics, and then from this model we have designed soft sensors to estimate the key variables and designed the controller laws. On-line data illustrate the interest of obtained results.
  While working on this project, we faced the question concerning the choice of the units in which we had to write the equations. We were concerned by writing algorithms independent of this choice as the reactors dynamics is. This questioning is at the origin of a new point of view on parameter estimations and observer design. Our major contribution lies in an invariant way to measure the estimation errors. Under some assumptions, the construction of such invariant errors can be done explicitly via Cartan's moving frame method. We illustrate these concepts on the polymerization reactor models those equations are invariant with respect to the transformations group associated to unit changes.
• "Modeling and Simulation of Coupled Non-Linear Systems", by S. Pushpavanam of the Department of Chemical Engineering, I.I.T Madras, India.
  The design of individual units such as reactors and separators has been investigated extensively. When the processes occurring in these units are non-linear these systems exhibit different kinds of exotic behavior. For example autocatalytic reactions and non-isothermal reactions occuring in CSTR?s are known to exhibit multiple steady-states and sustained periodic oscillations. Similar behavior has been reported for separation processes such as distillation columns under specific control strategies.
  In a typical process flow sheet a reactor is coupled to a downstream separator via a recycle stream when the conversion in the reactor is low. Such processes occur for example in the manufacture of ammonia, methanol. The recycle stream is the reactant rich stream from the separator. This coupling ensures that the downstream separator can affect the performance of the upstream reactor.
  The effect of this coupling is studied using a CSTR to model the reactor and a flash or distillation column to model the separator. The operation of the separator constrains the performance of the coupled system. It is established that there are regions of high feed rates when the system has no feasible steady solution. The performance of the system for different control strategies is discussed.
  Applications of singularity theory for analysis of steady state behavior and bifurcation theory for dynamic behavior enable us to obtain a comprehensive understanding of the coupled system. Analytical and semi-analytical results will be analysed to appreciate the understanding of the behavior of the coupled system
  One important feature is that the coupling induces a delay or a transportation lag from one unit to the other. The effect of this delay on the system behavior is studied when the delay arises in the recycle stream or in the stream from the reactor to the separator. It is found that delay renders a control strategy, which is otherwise favorable unfavorable and vice versa.
  Our efforts towards developing of a generalised approach to understand the behavior of these coupled reactor separator systems will be dwelt upon.

Venue

Tourist Attractions in Ghent

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.

Major touristic 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.

Weather

You can register by sending e-mail to dcons@world.std.com. Please also state if you want lunch (complimentary) at the venue. (An adapted menu can be obtained for special requirements, e.g., vegetarian.)

For the latest information, consult the annual seminar's Web site at www.mackie-workshops.com