PRocess control Chapter references

The term control panel refers to the instrumentation console in a central control room through which process information is communicated to the process worker and via which the worker changes the state of the process. This category includes display elements such as chart recorders, bar indicators, dials, and modem VDU-based systems together with control elements such as buttons, switches, track balls and mice. The control panel is the human-machine interface (see Chapter 2) that has traditionally received the most attention from human factors specialists. 

The general background of process design, flowsheets, and process control is reviewed in the introductory chapters. The major kinds of operations and equipment are treated in individual chapters. Information about peripheral and less widely employed equipment in chemical plants is concentrated in Chapter 19 with references to key works of as much practical value as possible. Because decisions often must be based on economic grounds, Chapter 20, on costs of equipment, rounds out the book. Appendixes provide examples of equipment rating forms and manufacturers questionnaires. 

This chapter is concerned with the mathematical modeling of coupled chemical reaction and heat and mass transfer processes occurring in porous catalysts. It focuses primarily on steady state catalyst operation which is the preferred industrial practice. Stationary operation may be important for the startup and shutdown of an industrial reactor, or with respect to dynamic process control. However, these effects are not discussed here in great detail because of the limited space available. Instead, the interested reader is referred to the various related monographs and articles available in the literature [6, 31, 46-49]. 

The intent in this chapter is not to present in great detail the mathematics behind the statistical methods discussed. An excellent reference manual assembled by the Automotive Industry Action Group (AIAG), Fundamental Statistical Process Control, details process control systems, variation, action on special or common causes, process control and capability, process improvement, control charting, and benefits derived from using each of these tools. Reprinted with permission from the Fundamental Statistacal Process Control Reference Manual (Chrysler, Ford, General Motors Supplier uality Requirements Task Force , Measurement Systems Analysis, MSA Second Edition, 1995, ASQC Press. 

It is not necessary to read all chapters of this book in sequence. For some readers the book may be a reference to answer specific questions. However, all readers should familiarize themselves with the content of Chapters 2-4 and 7 before they start solving chromatographic separations. Chapter 5 gives an overview of different chromatographic processes while Chapter 6 provides a detailed introduction to modeling and parameter estimation. These chapters, as well as Chapter 8 on chromatographic reactors and Chapter 9 on process control, should be read as the need arises. The book may not provide answers to all questions. In which case, the reader can obtain further information from the cited literature. 

Chapter 5. For additional study on the degrees of freedom and their impact on the design of process control systems, the reader should consult the following references ... 

The possibility of controlling a crystallization process by a suitable tuning of the physicochemical properties of the polymeric substrate has enhanced interest toward the preparation of specifically modified membranes. In particular, theoretical and experimental investigations that are the subject of this chapter refer to (i) Monbranes prepared from copolymers to modulate the hydrophobicity and (ii) Microporous hydrophobic membranes modified by using additives in the casting solution to modulate the morphology in terms of pore size and porosity. 

Oromucosal suspensions are prepared in the same way as suspensions for cutaneous use (see Sect. 12.7.3). So also for in-process controls reference is made to those chapters. 

Layers of protection There are many independent layers of protection provided in the control measure in addition to the basic process control system. These layers of protection make the control measures more robust. Fig. 11/4.5.4-1 may be referred to for more detail. Detailed discussions are available in Chapter V. Common mode failure Common mode failure refers to the failure of more than one control system on account of a common cause, which underlines the importance of independent layers of protection. However, common cause can affect both engineering and administrative controls. So, while considering the adequacy of control measures used for risk prevention/reduction/mitigation, etc. it is necessary and important to see that all such control measures are not only independent but also do not suffer from common mode fculure—discussed in later part of the book. 

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