Process topology

Classification of Batch Scheduling Problems 165 (1) Process topology... 

Process topology Equipment assignment Equipment connectivity Inventory storage policies Material transfer Batch size... 

Given the process topology, an unoriented graph is built where nodes correspond to units and arcs represent process streams. The process graph contains an environment node from which the process receives feeds, and to which it supplies products. 

Once the process variables have been classified, a great deal of information about the process topology is also available. The question now is how to use the classification and this information to attack other problems. In a real process we will have different kind of problems to solve and the goals will vary from one process to another. Among the possible situations that may be encountered are the following ... 

Once the information flowsheet is set up, the determination of the process topology is easy, that is, you can immediately write down the stream interconnections between the modules (or subroutines) that have to be included in the input data set. For Fig. 5.5 the matrix of stream connections (the process matrix) is (a negative sign designates an exit stream)... 

The behavior of process steps and phase systems can be represented by mathematical models (see the modeled-by relations in Fig. 1). In order to map the process topology to the model, process ports and connectors have to be related as well as process states and couplings by corresponding modeled-by relations. It must be considered that the relations between process design and model concepts are rather complex. Depending on the design context, a process step (such as separation) can be represented by different mathematical models (e.g. a linear splitter or a rigorous distillation column) and a certain mathematical model (such as a first-order transfer block) can be used to... 

The first step to apply some model-based application is to specify a suitable model for each process step. Basically, this step establishes the modeled-by relations (cf. Fig. 1) between process steps and phase systems on the one hand and models on the other hand. Mapping the process topology to the model to be generated is taken care of by the automatic model generation step. 

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