A generic approach to the automated startup and shutdown of processing units using sequential function charts

Abstract

Automated start–up and shutdown procedures increase the profitability and safety of a process, but are difficult to implement due to the complex nature of the concepts that must be incorporated. Generic components used specifically for the implementation of automated startup and shutdown procedures were defined to streamline the implementation process. The generic components developed are based on Sequential Function Charts and were applied to the startup of a fixed–bed gasification unit, for which a dynamic simulation model was developed. The application showed that the automated startup can be defined by a few generic components and that the flexibility of the startup procedure is increased through the incorporation of a fault accommodation module. The use of a visual–based definition of sequential processes increases the understanding of the complex scheduling procedures as well as the efficiency of the development of these automated procedures. In addition, iterative learning was incorporated into the generic definition to optimise controller performance during the non–linear phases of operation.