A case study in hybrid process safety verification

A recently developed, model-based methodology for the verification of chemical process safety is applied to a batch fertiliser production process. The latter is modelled within a discrete/continuous modelling framework to represent the hybrid characteristics of a processing system involving batch operations as well as discrete logic control. The optimisation-based safety verification technique aims at determining whether the process and its control system are able to satisfy the safety and operability specifications despite the possibility of human error and equipment failure. The results of the analysis are compared to those of different safety verification procedures proposed in the past. The feasibility and benefits of using rigorous, model-based techniques as opposed to qualitative methods for safety assessment are highlighted.