Sustainable Process Intensification Using Building Blocks

Process intensification (PI) is a design concept that offers innovative solutions for making a substantial improvement in terms of cost, energy efficiency, emission, environmental footprint, processing volume, and safety of a chemical process. Incorporation of PI principles at the conceptual design stage can pave the way for more sustainable solutions. However, it is not trivial to identify effective intensification pathways considering the various trade-offs between multiple conflicting performance metrics. To that end, we combine the building block-based systematic PI (Demirel, Li, and Hasan, Comp. Chem. Eng., 2017, 150, 2–38) with the ε-constraint-based multiobjective optimization to synthesize both economically attractive and environmentally sustainable chemical process systems. We successfully apply this approach to discover several novel intensification pathways for an industrially relevant chemical process for ethylene glycol production. These new pathways suggest nonintuitive flowsheets involving partial intensification, as opposed to complete merging of reaction and separation phenomena. Partial intensification significantly increases the return on investment while reducing the indirect CO2 emissions when compared to traditional nonintensified and intensified designs.