18th IFAC World Congress

Lecture Notes in Control and Information Sciences, 2007

This paper reports the experiences and results of a project aimed at designing an automatic control scheme for titanium dioxide rotary kilns. The process was studied by way of computer simulations, both steadystate and dynamic, from which a low order model was derived by matching the input-output frequency responses. Use of LQG theory then led to the conclusion that the kiln can be considered as a single-input, singleoutput process. Plant trials and simulation studies finally led to the adoption of a control scheme incorporating a self-tuning regulator in a feedback loop around a kiln controlled by a discrete regulator designed on minimum-variance principles. This scheme has been in use for three years and resulted in great improvement in control performance. Long term industrial results are presented. Practical considerations concerning implementation and acceptance by plant personnel are given.

IEEE Control Systems Magazine, 2002

ontrol systems technology is incredibly diverse. Applications of the technology are also diverse, ranging from very large, complex systems to relatively simple, microlevel devices. System costs may range from millions for large industrial plants to just a few dollars for mass-produced products. Performance is also diverse, ranging from ultra precision to only modest levels that are nevertheless completely satisfactory for their unique requirements. Furthermore, many diverse methodologies are available to control designers for use in increasing performance, reducing cost, improving robustness, and/or achieving a variety of other benefits. Virtually all dynamical systems-whether mechanical, electrical, chemical, economic, or social-can be improved with control technology. Most practical implementations, however, still require challenging innovations by designers to fully realize the potential of our diverse methodologies. This article reviews three recent examples of such innovations.

Recent developments in nonlinear systems theory combined with advances in control system hardware and software make the practical application of nonlinear process control strategies a reality. This Recent research efforts have concentrated on providing control system design techniques to handle many of the characteristics shown in . Adaptive control ) was promoted as a technique to solve the nonlinear problem by 'relinearizing" the process model as the process moved into different "linear" operating regions, as well as to estimate time-varying parameters (generally linear system based). Robust control system design techniques (Doyle and Stein, 1981; Doyle, 1982) were developed to account for model uncertainty. Internal model control (IMC) (Garcia and Morari, 1982) was developed to provide a transparent framework for process control system design and to explicitly handle manipulated variable constraints. Holt and Morari (1985) analyzed the effect of process deadtime in multivariable systems. Morari (1987) reviewed the three critiques (Fose, 1973; Lee and Weekman, 1976; Kestenbaum et al., 1976) and con-variables

This document contains my own solutions to the problems proposed at the end of each chapter of the book ”Process Modelling, Simulation and Control for Chemical Engineers” Second Edition, by William L. Luyben.

This document contains my own solutions to the problems proposed at the end of each chapter of the book ”Process Modelling, Simulation and Control for Chemical Engineers” Second Edition, by William L. Luyben.

2003

There are a variety of courses in a standard chemical engineering curriculum, ranging from the introductory material and energy balances course, and culminating with the capstone process design course. The focus of virtually all of these courses is on steady-state behavior; the rare exceptions include the analysis of batch reactors and batch distillation in the reaction engineering and equilibrium stage operations courses, respectively. A concern of a practicing process engineer, on the otherhand, is how to best operate a process plant where everything seems to be changing. The process dynamics and control course is where students must gain an appreciation for the dynamic nature of chemical processes, and develop strategies to operate these processes.

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The issue of control structure selection, where the control system designer must make decisions as to what variables need to be controlled and the corresponding manipulated variables, is usually treated in a very perfunctory manner in courses on control theory. In practical chemical process operation, it is this choice of the control structure t h a t turns out to be crucial towards effective disturbance rejection and maximizing process profitability. Given the large number of control degrees-of-freedom even for the simplest of chemical processes with material/energy recycle, how does one systematically design an effective plant-wide control system? This course addresses the same using an engineering common sense approach. Essential process control theory fundamentals are very briefly covered followed b y control structure design for common unit operations such as reactors, distillation columns, heat exchangers and miscellaneous operations (furnaces, refrigeration systems etc). Issues in plantwide control such as proper inventory management and effect of material/energy recycle are then highlighted followed by comprehensive plant-wide control system design case-studies on example processes. Control structure design considerations for maximizing plant profitability are explicitly covered. Based on the case-studies, a systematic plant-wide control system design procedure is developed and demonstrated on example processes. The course broadly covers process control as practiced in the process industry and prepares the ChE student for a career in process operations. Practicing engineers will also find the material useful for improving the efficiency and profitability of their processes.

IEEE Transactions on Control Systems Technology, 2000

This index covers all technical items-papers, correspondence, reviews, etc.-that appeared in this periodical during 2009, and items from previous years that were commented upon or corrected in 2009. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author's name. The primary entry includes the coauthors' names, the title of the paper or other item, and its location, specified by the publication abbreviation, year, month, and inclusive pagination. The Subject Index contains entries describing the item under all appropriate subject headings, plus the first author's name, the publication abbreviation, month, and year, and inclusive pages. Note that the item title is found only under the primary entry in the Author Index.