Process Control Design for Industrial Applications

7Modeling and Control of an Elementary Industrial Process

In this chapter, our aim is to present the design of closed-loop control systems that are integrated into an automation solution. We describe the methodology for developing different models that already exist in elementary process engineering (fluid flow, energy and mass transfer and chemical processes) based on the concepts introduced in Chapter 1. First of all, we will evaluate the often nonlinear models of knowledge obtained from laws of physics; next, we will calculate tangent behavior models, which are represented by differential equations or by transfer functions in order to obtain the control models that are used for designing control algorithms. Sometimes the control model results from an identification operation; although the identified model has an abstract form, it expresses the approximate dynamics of the controlled process. After evaluating this last class of models, we take a look at computing the algorithm for systems that control various parameters of the process, proposing the best methods for designing traditional PID and polynomial algorithms, which are easy to implement in practice. For control, we consider some representative processes of fluid flow, supply drain of liquids, thermoenergy transfer and chemical processes.

7.1. Modeling and control of fluid transfer processes

To design fluid transfer process control systems in a real application, two steps must be followed: evaluate the dynamic models ...