(173b) Identification of Synergistic Process Intensification Opportunities in Chemical Plants

Due to the recent trends in increased competitions, stringent environmental regulations, possible restrictions on CO₂ emissions, and increased awareness of process safety and sustainability, there is a surge to re-evaluate and identify potential hotspots for improving the efficiency of existing processes without making many structural and design changes. This presents an opportunity for the analysis and identification of potential process intensification opportunities. Process intensification is referred to as any drastic improvement in processing volume, cost, energy, profit, environmental footprint, and safety of a chemical plant. It can be achieved through tight integration, optimization, or union (merging) of various physicochemical phenomena, such as reaction, separation, phase dividing, phase change, heating, cooling, etc., in multi-tasking units. Examples of multi-tasking units include reactive distillation, dividing wall columns, and membrane reactors.While we have made great strides in the areas of systematic process integration and optimization, our efforts in merging multiple phenomena for intensification are mostly based on heuristics, experience, and innovation. It is in this context that we present a mathematical framework to systematically identify novel pathways and hotspots for exploiting synergistic effects for effective process intensification. Synergy is the combined effect of cooperative interactions between two or more organizations, substances, or other agents that is greater than the sum of their separate effects. Synergistic combination helps achieve seemingly difficult targets by attenuating the underlying conflicts. We analyze synergy based on two types of interactions, namely the variable-variable interactions (VVI) and the phenomena-phenomena interactions (PPI). VVI-based synergistic effects contribute to intensification through tight integration and optimization, when no topological changes are expected. The PPI-based synergistic effects, on the other hand, lead to intensification through the union of two or more phenomena in a multifunctional unit. We determine intensification hotspots and topological changes that maximize the synergy score of a process represented using a PPI graph. A PPI graph of a process is constructed by decomposing unit operations into fundamental physicochemical phenomena and connecting them with material and energy streams. An algorithm is developed to calculate the synergy scores based on the topology connection and centrality of the PPI network. Other associated scores are coupled with to adjust the topology-based scores. We demonstrate the applicability of the proposed approach using several processes including (i) integrated carbon capture and conversion, and (ii) natural gas to methanol process.