Process network synthesis: Problem definition

A Preliminary Study of the Application of the P-graph Methodology for Organization-based Multiagent System Designs: Assessment

“…Thus, a given network may give rise to a variety of processes, or process networks, producing the desired products, and each of such process networks corresponds to a sub-network, that can be considered regarded as its structure. Energy and raw material consumption strongly depend on the selection of a process structure; thus, the optimal design of such a process structure, i.e., the process network synthesis (PNS), or process synthesis in short, has both environmental and economic implications [14].…”

“…These methods can be classified according to whether they are based on heuristics or algorithms, i.e., mathematical programming approaches. The majority, if not all, of these methods, however, may not be sufficiently effective for PNS of a realistic or industrial scale, process because of its combinatorial complexity arising from the involvement of a large number of interconnected loops [14]. To cope with this, an innovative approach based on P-graphs (process graphs), which are unique, mathematically rigorous bipartite graphs, has been proposed to facilitate the process network synthesis [10].…”

Heuristic Algorithms for the Robust PNS Problem

“…It is a directed bipartite graph where the set of vertices is M U O, and have the following two sets of edges: 1) Edges which connect the input materials to their operating unit 2) Edges which connect the operating units to their output materials Then some of the subgraphs of this P-graph describe the feasible solutions which produce the required materials from the raw materials. In [9] it is shown that a subgraph In the structural PNS problem we assign, to each operating unit u, a cost denoted by c(u) and the goal is to find a feasible solution, where the total cost of the contained operating units is minimal. In the robust version we assign two costs to the operating units: a nominal cost denoted by c(u) and an extra cost denoted by e(u).…”

“…In the structural model the amounts of the material flows are not taken into account thus the cost of an operating unit is a constant, and the cost of a subgraph is the sum of the costs of the operating units contained in it. The foundations of PNS problem can be found in [9,10], we will recall only the most important definitions in the next section.…”

Reduction techniques for the PNS problems: a novel technique and a review

“…From the structural point of view process network synthesis can be modeled by the P-graph technique Friedler et al 1998). The complexity of these problems highly depends on the mathematical model of the operating units.…”