The use of flow models for design of plant operating procedures

It is shown how operating procedures can be structured into logically consistent parts by a decomposition into sequential and concurrent action sets. The decomposition is shown to originate from the topology of the pattern of material and energy flow in the plant, and to the nature of the specific control task considered. This analysis provides valuable information of how plant structure can be used explicitly in procedure design. It is shown how a category of models called flow models developed by the writer, can be used to represent flow topology in material and energy processing plants. Flow models will be used as a way of dealing with plant topology in procedure design. The observation which leads to the consideration of flow models for procedure design is that e.g. start-up procedures for apparently dissimilar plant components as pumps and boilers show some common structural features. The reason for this is that the components are functionally equivalent in certain phases of their operation. Functional equivalence of components or systems can be expressed by using the language of flow models. (orig./HP)