Throughput Maximization in Multipurpose Batch Plants: S-graph Vs Time Point Based Methods

This paper presents a performance comparative study between a graph-theoretic framework based on the S-graph representation and a mathematical programming approach based on uneven discretization of the time horizon using time points. Both techniques consider maximization of throughput in multipurpose batch plants over a predefined time horizon. The major contrast between these techniques is the irrelevance of time discretization in the S-graph approach and the necessity of presupposition of time points in the mathematical programming approach. Moreover, the S-graph provides added unique advantages like readily exploiting the structure of the problem at hand and elimination of infeasible solutions prior to embarking on problem solution. In all the problems considered, the Sgraph succeeded in obtaining solutions in relatively short CPU times compared to the mathematical programming approach. In essence, the mathematical programming approach could not provide solutions in some problems of industrial relevance.