Plant, Equipment and Utilities: Instrumentation and Process Control

Abstract

This article provides an overview of the widely used instrumentation, control paradigms and their novel counterparts applied in a variety of process industries, including the dairy industry. Industrial evolution in the second half of the 20th century and early part of the 21st century was influenced mostly by the following interrelated factors: progress in digital technology, advances in science and engineering, evolution of societal requirements and demands, globalization, and sophistication of business concepts. Developments in digital technology and in systems theory have led to major progress in sensor and information technology and a revolution in the availability of distributed control systems and open software applications. New concepts, particularly knowledge-based measurements, and advanced control methodologies are steadily being brought into the practice of process operation, performing online and in real time. Although basic dairy processes have changed little in the past several decades, the general demands of lower cost, higher product quality and safety, and more environmentally friendly solutions have led to demands for improved control structures versus the traditional approach. Societal and economic factors have driven evolution in instrumentation and process control in the same direction. Consumer demands for health, safety, quality and sustainability reflected in the foods (including dairy) they consume, all delivered at an acceptable price point, create considerable pressure for food manufacturers. These demands, together with the evolution of company strategy from local to global outlook, all impact on plant investment decisions, favoring process automation for cleaner and safer operation, higher product quality and improved process efficiency and productivity. Plant automation is inextricably linked to instrumentation, control system configurations, data communications and theoretical control structures. This chapter provides the reader with an overview of instrumentation, addressing in particular both basic and advanced concepts concerning sensors, advanced mathematical algorithms and the issue of how to integrate local hardware for automatic control, usually dispersed throughout the plant or even between plants. In terms of process control, an overview is provided on the proportional integral derivative (PID) controller as a control engineering practice that has been established for decades, various statistical process control techniques widely implemented in batch and fed-batch dairy plants, and intelligent control alternatives. Fuzzy logic control systems and artificial neural network-based model predictive control are the main intelligent control paradigms described herein. Finally, an overview is provided of the impact of the fourth industrial revolution (Industry 4.0) on the dairy production and processing industry, providing potential for better process control and automation, and enhanced product safety, quality and consistency all at a reduced cost.