Process Control for the Process Industries — Part 2: Steady-State Characteristics

Control theory and practice are generally considered to be in the realm of electrical engineering, and they are included in undergraduate and graduate courses in electrical engineering. However, the technologies developed and studied by EEs are not effective at providing solutions to the control problems encountered in the process industries. Five aspects of chemical processing contribute to the unique nature of their control: disturbances; dead time; dynamic models; economics; and the multivariable nature of industrial processes. Part 1, in the March issue, focused on the first three of these factors, which relate to the dynamic behavior of the process, and why they are relevant to the practice of process control. This article deals with the last two, which relate to the steady-state characteristics of the process.