Designing Controls for the Process Industries

Book excerpt: Offering a modern, process-oriented approach emphasizing process control scheme development instead of extended coverage of LaPlace space descriptions of process dynamics, this text focuses on aspects that are most important for process engineering in the 21st century. Instead of starting with the controller, the book starts with the process and moves on to how basic regulatory control schemes can be designed to achieve the process' objectives while maintaining stable operations. In addition to continuous control concepts, process and control system dynamics are embedded into the text with each new concept presented. The book also includes sections on batch and semi-batch processes and safety automation within each concept area. It discusses the four most common process control loops--feedback, feedforward, ratio, and cascade--and discusses application of these techniques for process control schemes for the most common types of unit operations. It also discusses more advanced and less commonly used regulatory control options such as override, allocation, and split range controllers, includes an introduction to higher level automation functions, and provides guidance for ways to increase the overall safety, stability, and efficiency for many process applications. It introduces the theory behind the most common types of controllers used in the process industries and also provides various additional plant automation-related subjects.