Industrial & Engineering Chemistry Research, Vol.58, No.19, 8172-8183, 2019
Design Approach To Synthesize, Validate, and Evaluate Operating Procedures Based on Untimed Automata and Dynamic Simulation
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.