Processes dedicated/flexible

Bok, Grossmann and Park (2000) explained a classification of chemical process networks and characterized them as either dedicated or flexible processes. Dedicated processes operate at one mode and for high volume products whereas flexible processes operate at different modes and produce different products at different times. In the formulation introduced in this chapter, we account for different... 

Chemical research is driven by many goals, and it progresses in many different ways. The essential traits of a good researcher are curiosity, creativity, flexibility, and dedication. Some chemical advances come from a direct assault on a known problem. A classic example is the development of the Hall process for refining aluminum from its ores, which we describe in Chapter 21,. As a contemporary example, many scientists around the world are working at a feverish pace to develop a vaccine against the AIDS virus. 

Sahinidis, N.V. and Grossmann, I.E. (1991b) Multiperiod investment model for processing networks with dedicated and flexible plants. Industrial el Engineering Chemistry Research, 30, 1165. 

Finally, I want to thank the people at Pearson, whose dedication and flexibility contributed to the completion of this project. Executive Editor, Jeanne Zalesky and Senior Project Editor, Jennifer Hart kept the project moving, ensured the needed resources were available, and made many useful comments and suggestions. Project Managers Marisa Taylor, Kate Thomas, and Shari Toron who kept the production process organized, on track, and on schedule. It has been a pleasure working with all these thoroughly professional and competent people. 

It should be noted that most of the mentioned representations of protein structure imply that the protein remains rigid during the docking process. As a matter of fact, docking under the assumption of a rigid protein is still common practice in standard applications. Although an acceptable simplification unda certain circumstances, it can represent a serious limitation if only unbound protein structures are available. As a consequence,the inclusion of protein flexibility in the docking process is an active area of research, and a separate section is dedicated to this issue (cf. Section 3.2.1). 

In fine and specialty chemicals production the process cost is a less relevant aspect on the other hand, the time taken to realize the industrial production is typically the critical factor. This aspect, together with the limited resources dedicated for R D, determine the preference in companies for multipurpose catalysts with respect to optimized, but more specific, catalysts. This applies also to the process itself where simpler, not optimized, batch reactors are preferred to better, but less flexible, more complex operations. This is one of the key aspects to consider in evaluating the use of multiphase operations in the synthesis of this class of chemicals. 

The equipment supplier will therefore aim to offer versatile, multi-purpose equipment that can be used in a range of processes. Most of it will be stainless steel or glass lined, to avoid problems with contamination or corrosion. Wherever possible, a single reaction vessel is dedicated to one particular process, and usually each preparation is performed in a self-contained area. This situation has eased somewhat in recent years, and more multi-use equipment is being installed. There is still not the flexibility in equipment use that one might expect in comparison, say, with the dyestuffs industry, but there is a trend in that direction. 

All equipment should be easy to clean and steam sterilizable and have a sanitary finish. If the facility is not dedicated to one product, computer automated recipes provide the greatest control and flexibility for processing. The overall operation must be designed so as to minimize the personnel required to operate the equipment and thus minimize the exposure of product... 

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