Abstract
The hierarchical structure of pulpmill control is defined in terms of six levels-planning, scheduling, supervisory, mufti-variable, direct and data acquisition. The functions of each of these levels for a continuous digester are discussed. The design of the scheduling level is investigated for the case of a single pulpmill that must produce two species sequentially. It is shown to be primarily the problem of designing a feedforward control system for a process with a major dead time.
The relationship of plant design to controllability is discussed, using the example of determining the size of the vuln storage tanks.
Download PDF