Achieving More Sustainable Solutions through Process Intensification

More sustainable production points to, among others, reduced waste, increased efficiency, reduced environmental impact, increased profit. Traditionally, problems related to process synthesis, process intensification and more sustainable process design have been solved as separate problems. However, process intensification and more sustainable process design should be viewed as part of the general process synthesis problem. That is, the search space for the optimal process should include PI-options and the criteria for evaluating alternatives should be related to measures of sustainability. To achieve this, a two-stage approach, where a model-based synthesis method to systematically generate and evaluate intensified and more sustainable alternatives in the first stage and an experiment-model based validation in the second stage, has been developed. In this way, the search for more sustainable alternatives is done very quickly, reliably and systematically over a wide range, while resources are preserved for focused validation of only the most sustainable candidates in the second-stage. This approach, however, would be limited to intensification based only on “known” unit operations, unless the PI process synthesis/design is considered at a lower level of aggregation, namely the phenomena level. That is, the model-based synthesis method must employ models at lower levels of aggregation and through combination rules for phenomena, and generate (synthesize) new intensified unit operations. Established procedures for computer aided molecular design is adopted since combination of phenomena to form unit operations with desired objectives is, in principle, similar to combining atoms to form molecules with desired properties. The concept of the phenomena-based method for process intensification leading to more sustainable process design will be presented together with illustrations of its application through case studies. Aspects such as need for models, computer-aided framework, the work-flow and data-flow for the PI synthesis method will also be highlighted.