Chemical Engineering Science 57 (2002) 4255
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Editorial
Particulate Processes: a Special Issue of Chemical Engineering Science Many products of the chemical process industries represent disperse systems like powders, granulates, tablets, suspensions, pastes or polymer dispersions and emulsions, for example. Particulate processes, like crystallization, granulation, precipitation and polymerization processes are used for their production. Although some of these processes have been studied by chemical engineers for quite some time, due to their complexity, there are still lots of open questions. Major problems in particulate processes these days involve: measurement and characterization of population kinetics and particle properties, prediction of product properties from particle properties, modeling and simulation of particulate processes for model-based process analysis, design and control. The present special issue contains selected papers from a workshop on Particulate Processes held in October 2000 at the newly founded Max-Planck-Institute for Dynamics of Complex Technical Systems in Magdeburg. The objective of this workshop was to bring together leading experts from academia and industries to discuss the status quo and to identify future challenges in this 1eld. Emphasis was on population balance modeling and simulation of particulate processes and on model-based process design, analysis and control. The workshop was supported by the German competence network for chemical engineering Pro 3 and by the joint research project SFB 412 on computer-aided modeling and simulation for the analysis, synthesis and control of chemical processes. The outline of this special issue is the following: First, an introduction to particulate processes from the industrial point of view is given by Borho from BASF AG. The need for computational tools for an e7ective design of particulate processes in industries is emphasized. Focus in the second part is on fundamentals of particulate processes and measurement techniques. Fundamentals involve the prediction of nucleation, agglomeration, attrition and growth in crystallization processes in the contributions by Mersmann and co-workers and Myerson and Mohan. Fundamental kinetic, colloidal and rheological phenomena in precipitation processes are covered in the contribution by Kind. Characterization of particle systems for better product design is the topic of the contribution by Polke and Sch9afer. Finally, L9o7elmann and Mersmann introduce a new sensor for online measurement of supersaturation, which is a key variable for controlling crystallization processes from solution or melt.
The third part is concerned with modeling and simulation of particulate processes. Emphasis is on new modeling approaches based on population balances as well as new computational methods to solve these complex models e;ciently. Applications are concerned with crystallization (Gerstlauer et al. and Motz et al.), aerosol formation (Schaber et al.), coagulation (Schuetz and Piesche) and granulation (Heinrich et al.). New computational techniques are treated in the contributions by Motz et al. and Schaber et al. The fourth and last part contains three contributions on dynamics and control of particulate processes. The 1rst contribution of Pathath and Kienle is concerned with the well-known phenomenon of self-sustained oscillations in crystallization processes. Tools and methods from bifurcation theory are used to gain deeper insight into the nonlinear dynamic behavior. In the second contribution, by Vollmer and Raisch, it is shown how oscillatory behavior can be stabilized by means of suitable feedback control. In particular, an H∞ approach is used to design a robust controller. Finally, Immanuel and Doyle III describe a method for the generation of open-loop optimal feed pro1les to attain a target particle size distribution in semi-batch emulsion co-polymerization. The editors like to thank Heike Lorenz, Anette Perlberg, Jaqueline Kaufmann and Tobias Back1sch for their help in organizing the workshop and Stefan Motz and Marianne Sch9ops for their help in preparing this special issue. Finally, the help of A. Bell in organizing the review of our own manuscripts is greatly acknowledged.
0009-2509/02/$ - see front matter ? 2002 Elsevier Science Ltd. All rights reserved. PII: S 0 0 0 9 - 2 5 0 9 ( 0 2 ) 0 0 3 4 1 - X
E. D. Gilles Max-Planck-Institut fur Dynamik komplexer technischer Systeme; Sandtorstr. 1 D-39106 Magdeburg; Germany Institut fur Systemdynamik und Regelungstechnik Universitat Stuttgart; Pfa'enwaldring 9 D-70550 Stuttgart; Germany A. Kienle Max-Planck-Institut fur Dynamik komplexer technischer Systeme; Sandtorstr. 1 D-39106 Magdeburg; Germany Lehrstuhl fur Automatisierungstechnik Otto-von-Guericke Universitat Magdeburg Universitatsplatz 2; 39106 Magdeburg; Germany