A systematic design approach is proposed
in this paper to synthesize,
validate, and evaluate operating procedures for any given chemical
process. To facilitate efficient procedure synthesis, the extended
finite automata (EFA) are adopted in this work to model all components
in a chemical process according to simple configuration rules. The
intended operation is then divided into several stages on a case-by-case
basis and each characterized with a unique set of attributes, e.g.,
stable operation, condition adjustment, phase change, reaction, material
charging, and/or unloading. The control specifications of every stage
should then be stipulated accordingly and described with automata.
All observable event traces (OETs) are extracted from the system model
assembled by synchronizing all aforementioned automata. The candidate
operating procedures can be summarized with sequential function charts
(SFCs) that mimic these OETs. The commercial package ASPEN PLUS DYNAMICS
has been used to validate such SFCs in simulation studies. Since several
candidates can usually be generated, it is also necessary to compare
the simulation results so as to identify the most suitable procedure.
Three realistic examples, i.e., the semibatch reaction process and
the startup operations of flash drum and distillation column, are
presented in this paper to demonstrate the merits of the proposed
approach.