INTERACTIVE DIRECT ESTIMATION TECHNIQUE USED FOR CHEMICAL KINETICS MODELLING AND SIMULATION

Gheorghe MARIA
(Lab Chem.Engineering & Industrial Chemistry, Swiss Federal Inst. of Technology (ETH), Zurich, CH-8092)

ABSTRACT

A new short-cut (direct) estimation procedure is presented in this paper, e.g. the Modified Integral transformation Procedure (MIP, Maria, 1993: Maria and Rippin, 1995), belonging to the direct estimation methods for (on-/off-)line identification of a chemical Kinetic Model (KM). Compared to classical direct techniques, the MIP adds supplementary artificial intelligence elements by including prior information about similar model structures. For the isothermal data under study, the MIP makes a rapid adaptation of similar KM structures and parameters describing previous processes stored in interactive kinetic data-banks, by developing similarity analysis based on species concentration trajectories. The problem decomposition and the model term-by-term sensitivity analysis, result in a very effective MIP for generating reliable initial parameter estimates of better quality than those derived from the classical short-cut techniques, especially for non-linear and ill-conditioned cases. Rapid and repeated application of the MIP to check different kinetics for adaptation or the same KM for different data sets allows a rapid process evaluation and simulation. Because MIP is not based on an iterative search, it has no convergence problems and requires no tuning factor. MIP is also suitable for on-line KM identification in dynamic processes, the interaction with the stored information allowing on-line adaptations of the model structure. Simple examples reveal the proposed procedure capabilities.

BIOGRAPHY

Gheorghe MARIA (40). M.Sc.: Ph.Dr. in Chemical Engineering (1987) at Polytechnic Univ. Bucharest (Romania)(Diss. title: 'Chemical Process Model Estimation'). Substitute (1982-1989) and asstn. professor (1990-1991) with the Dept.Chem.Eng. of the Polytechnic Univ. Bucharest. Since 1992 he works as res.asstn. with the Dept.Chem.Eng.& Industrial Chemistry at Swiss Federal Inst. of Technology (ETH) Zurich (Switzerland). He works in the area of chemical reaction engineering / chemical reactor and process modelling and simulation, and numerical information storage.

He developed a large number of chemical/kinetic models and proposed some new numerical estimation / optimization techniques:

an adaptive random search (MMA) in Comp.Chem.Eng. 1986
a concomitant model estimation/reduction procedure (CPEMR) in Chem.Eng.1989
a new short cut kinetic model estimation technique (MIP) (with the late Prof. D.Rippin in Comp.Chem.Eng.1995).

He has authored / co-authored 65 published papers (from which 30 in International Journals; 25 in International Conference Proceedings), 4 books on chemical process modelling (of which 3 for didactic purposes). In 1995 he presented a Plenary Lecture in ESCAPE5 Symp. (Computers Application in Chem.Eng.) on short-cut techniques for chemical kinetic modelling. He was awarded the Romanian Academy of Sci. Prize for research studies and semi-industrialization of a catalytic process in 1985. He is member of the New York Acad.Sci., reviewer for 'Computers & Chem.Eng.' and 'Chem.Eng.Sci.' journals, visitor at Univ.Porto (Portugal), Princeton Univ. (USA), Queen's Univ. (Kingston, Canada), Ecole Polytechnique Lausanne (Suisse).

Dr. Gheorghe Maria
Technische Chemisches Lab
ETH-Zentrum
Universitat str. 6
CH-8092 Zurich, Switzerland
Tel : 41-1-632 3157 (Office)
e-mail : maria@tech.chem.ethz.ch