Model-based estimation and control methods for batch cooling crystallizers

This thesis contains results of research that was carried out during four years on methods to improve the predictability and reproducibility of the behavior of industrial crystallization processes. In this chapter an introduction to the work described in this thesis is given. The first part of this chapter sets the scene. An introduction to the crystallization process as it is used in industry is given, after which the current issues in operation of these processes in an industrial environment are discussed. The second part of the chapter introduces the research objectives which have been formulated and explains how these objectives result in the desired improvement in the operation of these processes. Finally the outline of the thesis is given. Separation of chemical components is one of the most important operations in modern process industry. Separation technology is of importance to extract and purify valuable components from a mixed component stream. It also plays a major role in analysis methods, waste treatment and recycling and is of key importance in production processes. At the pharmaceutical company Du Pont it has been estimated in 1988 that for 70% of their products crystallization is involved in the production process [Larsen et al., 2006]. The worldwide market for pharmaceutical products in 2009 was estimated to be 597 Billion Euro ex-factory prices and the Dutch pharmaceutical industry produced in 2009 products with a combined worth of 5.7 Billion Euro [EFPIA, 2011]. In general, separation processes are large energy consumers, since one has to apply a force to initiate and continue the separation of components. After distillation, crystallization is the second 1 i i “thesis” — 2012/9/3 — 21:29 — page 2 — #16 i i