Process Dynamics and Control

Process Dynamics and Control
Instructor: Ali M. Sahlodin
Level: Undergraduate
Course outline
Successful operation of chemical processes, from startup to shutdown, is hinged upon a proper control system, the design and use of which require a good understanding of process dynamics and control methods. This course aims to familiarize the students with basic concepts on process dynamics and control, including dynamic modeling, feedback control, and common control systems. The students will learn how to analyze the performance and stability of simple control systems and how to use related software tools for performing their analysis.

Lecture slides
Process Dynamics Lecture 1 Class rules; introduction to process control. Video 1
Lecture 2 Dynamic modeling (mass and energy balance); numerical solution of dynamic models; nonlinear dynamics. Video 2, Video 3, Video 4
Lecture 3 Laplace transforms, their properties and application to solution of dynamic systems. Video 4, Video 5, Video 6
Lecture 4 Transfer functions for modeling processes with linear dynamics and nonlinear dynamics (upon linearization). Video 6
Lecture 5 Constructing composite input signals; dynamic behavior of first-order, integrating, and second-order processes subject to different input types. Important concepts regarding these systems such as steady-state gain, time constant, damping, overshoot, etc. Video 9, Video 10, Video 11
Lecture 6 Dynamic behavior of more complicated systems including those with numerator dynamics; related concepts such as inverse response.
Lecture 7 Detailed discussion of inverse response and overshoot in systems with numerator dynamics; block diagram representation of dynamic processes; systems with time delay; interacting systems (e.g., tanks in series); approximation of higher-order systems.
Process Control Lecture 8 Introduction to feedback control and terminology; basic control modes (e.g., on-off and proportional)
Lecture 9 Closed-loop response with proportional controllers and concept of offset; proportional-integral (PI) control.
Lecture 10 PI control (cont’d); derivative mode and proportional-integral-derivative control (PID); different forms of PID; practical challenges of PID controllers. Video 23
Lecture 11 Reset windup in PI controllers and how to counter it. Video 23
Lecture 12 Control instrumentation: sensors, transmitters; measurement accuracy and related concepts; control valves and their fail-safe modes. Video 23, Video 24, Video 25
Lecture 13 Valve characteristics and sizing Video 25, Video 26
Lecture 14 Stability of dynamic systems: definition and relation to transfer functions; process examples of stable and unstable systems Video 26
Lecture 15 Closed-loop transfer function for stability analysis; closed-loop stability of first- and second-order systems with proportional and PI control; stability of higher-order systems. Video 27, Video 28
Lecture 16 Stability analysis using root locus method. Video 28
Lecture 17 Stability analysis using frequency response; basic definitions such as phase angle and amplitude ratio; Bode diagram. Video 29
Lecture 18 Bode stability criterion; controller tuning and Ziegler-Nichols method. Video 29, Video 30
Lecture 19 Advanced control strategies: feedforward control; cascade control; time-delay compensation; override and split-range control. Video 30, Video 31

Learning codes
Description Related topic Software compatibility
Dynamic simulation of blending tank problem Dynamic modeling Octave & MATLAB
Dynamic simulation of nonlinear CSTR problem Nonlinear dynamic models Octave & MATLAB
Scilab (free Simulink counterpart) for dynamic modeling Block diagram simulation Scilab
First-order process with Proportional controller Proportional control Octave & MATLAB
Root locus for stability analysis Stability analysis Octave & MATLAB
Closed-loop stability of three tanks in series Stability analysis Octave & MATLAB
Plot of Bode diagram Stability analysis Octave
Sample assignments (in Farsi)
Assignment Related topic
Assignment 1 Dynamic modeling, transfer function, and analytical/numerical solution of simple processes.
Assignment 2 Transfer function for more complicated processes; closed-loop simulation using transfer function blocks.
Assignments 3-4 Cascade loops; delay handling; stability analysis.