Process Control and Automation - ACS Publications

FUNDAMENTALS. Process Control and Automation. SINCE the appearance of our last review, the chemical and petroleum industries have continued their rapi...
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FUNDAMENTALS

Process Control and Automation S I N C E the appearance of our last review, the chemical and petroleum industries have continued their rapid expansion of activity in the process control and process dynamics field. Several potential applications and developments of digital computers already in progress or under discussion are listed in the table. At least three different computers specifically designed or modified for process control have been announced, and several others are known to be in existence or under active development. \Yhile these computer manufacturers have in many cases generously offered to make systems engineering studies of the proposed installations, either alone or in cooperation with the chemical or petroleum company concerned, as part of the installation program, the burden still rests upon the chemical or petroleum companies to assure themselves that the proposed computer can d o the j o b for which it is being specified or that on the other hand, a simpler, cheaper control system might not be entirely adequate for the task desired. This requirement puts a n especially difficult load upon the already seriously undermanned chemical and petroleum personnel with a n adequate background to carry out such studies. \Vhile this shortage is acute a t present, it shows signs of easing in the not too distant future. Universities are actively seeking to upgrade their process control and instrumentation courses to include the fundamentals of servomechanism and process dynamics theories or to establish new courses for this purpose. They, a t the moment, face the same problems which industry has in staffing such programs. T h e American Institute of Chemical Engineers has just issued a special publication (7OF) presenting

THEODORE J. WILLIAMS i s engineering supervisor in charge of Monsanto's analog computer laboratory and systems engineering theory activities. He received the Ph.D. in Ch.E. from Penn State in 1955 and the M.S.in E.E. from Ohio State in 1956. Prior to joining Monsanto in 1956 he was assistant professor of chemical engineering a t the Air Force Institute of Technology.

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The most dramatic development in the field and the one which will have the greatest effect upon our future progress, both in magnitude and direction, has again come from outside the chemical and petroleum industries. This i s the tremendous effort being exerted by several of the defense electronics development companies and the digital computer manufacturers to sell digital computers as process control elements in chemical plants and petroleum refineries.

several proposed outlines of course content and associated laboratory work for such courses a t both the undergraduate and the graduate level. Also, the distinct shortage of text books in the field has eased somewhat with the appearance of t\yo excellent new ones this year (9F, 22F) and several others known to be in preparation. Beyond the use of digital computers for process control and the gains in education in process control and process dynamics. the next most important activity was in the continued development of instrumental methods of analysis of process streams in order to permit the inclusion of these instruments in process control loops. Excellent reviews of the state of the art in the various aspects of this field have been given by R. F. Wall in his monthly column in INDUSTRIAL A ~ D ENGINEERIW CHEMISTRY and in the continuation of the series of articles recently published by Control Engineering (8C, 47C, 42C). Also of grear importance to the future of process dynamics and control in the chemical and petroleum industries is the rapidly expanding application of analog computers as simulation tools for determining process kinetic constants, plant dynamic characteristics, and optimum process control configurations prior to or during the design of the plant unit. T h e purchase of several of these units by

INDUSTRIAL AND ENGINEERING CHEMISTRY

chemical companies has been announced ( 7 A , 2A). Published examples showing the facility and usefulness of these ma; chines include the solvent recovery process example by Lewis (7A) and the extraction system study of \Voods ( 7 9 A ) . T h e over-all subject of their applicability to chemical problems has been covered by two articles by Thomas (76.1) and by Williams (78