Plant control-engineering

The development of fiber optics technology, user-friendly displays, and enhanced data presentation capabihties have made on-line analysis acceptable within the plant manufactuting environment. However, it is apparent that a barrier stiU exists to some extent within many organizations between the process control engineers, the plant operations department, and the analytical function, and proper sampling is stiU the key to successful process analytical chemistry. The ultimate goal is not to handle the sample at ah. 

Limited Data First, plant data are limited. Unfortunately, those easiest to obtain are not necessarily the most useful. In many cases, the measurements that are absolutely required for accurate model development are unavailable. For those that are available, the sensitivity of the parameter estimate, model evaluation, and/or subsequent conclusion to a particiilar measurement may be very low. Design or control engineers seldom look at model development as the primaiy reason for placing sensors. Further, because equipment is frequently not operated in the intended region, the sensitive locations in space and time have shifted. Finally, because the cost-effectiveness of measurements can be difficult to justify, many plants are underinstru-mented. 

The critical role of analysts introduces a potential for bias that overrides all others—the an ysts evaluation of the plant information. Analysts must recognize that the operators methods, designers models, and control engineers models have merit but must so beware they can be misleading. If the analysts are not familiar with the unit, the explanations are seductive, particiilarly since there is the motivation to avoid antagonizing the operators and other engineers. 

VDIWDE 2180, Safeguarding of industrial process plants by means of process control engineering. 

Liaison with Control Engineering Department on Plant and Process Design... 

The purpose of the control plant is to maintain a working environment that is acceptable in terms of any statutory regulations and the custom and practice within an industry. The effectiveness of a control system is measured by the amount of dust or fumes it controls. Efficiency, on the other hand, is measured by the amount of power it takes to do the work. It is the job of the dust-control engineer to produce the most effective plant in the most efficient way, and the techniques of control will vary from one industry to another. All control plants will have either four or five elements, as shown in Figure 46.1, i.e. hoods, ducting, fan, collector and disposal. 

We gratefully acknowledge the past support of our research by the Southwest Florida Water Management District, The Florida Department of Natural Resources (Bureau of Aquatic Plant Research and Control), and the Aquatic Plant Control Research Program at the U.S. Engineer Waterways Experiment Station. 

Recall the footnote in Chapter 1 a process is referred to as a plant in control engineering. 

Chemical engineering is no longer confined to purely physical processes and the unit operations, and a number of important new topics, including reactor design, automatic control of plants, biochemical engineering, and the use of computers for both process design and control of chemical plant will be covered in a forthcoming Volume 3 which is in course of preparation. 

The duties of the control engineer include the programming of all necessary process operations, interlocking- and safety precautions into a control program, and avoiding the possibility of incorrect operations by the operators. The major part of the malfunctions which still remain should be detected during the commissioning of the plant. 

Davenport, GB. Understand the Air-Pollution Laws that Affect Chemical Process Industries Plants, Chem. Eng Progress, 40 (April 1992). de Nevers, N Air Pollution Control Engineering, 2nd Edition, The McGraw-Hill Companies. Inc.. New York, NY. 1999. 

Experienced process control engineers are usually responsible for the design and specification of automatic control schemes on large chemical plants. The book by Shinskey (1979) provides details of the practical... 

After completion of the detailed design, the control engineer then must devise the control strategies to ensure stable dynamic performance and to satisfy the operational requirements. The objective is to operate the plant in the face of potentially known and unknown disturbances, production rate changes, and transitions from one product to another. 

A major portion of the research presented in this paper was funded by the Aquatic Plant Control Research Program of the U.S Army Corps of Engineers. Permission was granted by the Chief of Engineers to publish this information. 

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