Application of Thermodynamic-Topological Analysis in the Design of Biorefineries: Development of a Design Strategy

Biorefineries have been widely studied during the last years and proposed as the best option to transform biomass systems into value-added products. Different methodologies have been proposed for the design of biorefineries: knowledge-based approach, early-stage approach, and superstructures, among others, which have been coupled to process improvement schemes as pinch analysis and process intensification. Regarding process design, it is necessary to ensure that the most advanced concepts are applied on the design to ensure efficient processes that direct to more sustainable processes. The processes that are currently being designed as biorefineries in many cases cannot be considered as completely efficient, because they are generally biased to designs based only in typical methods of process engineering. It is still necessary to implement further design strategies focused on increasing the efficiency and decreasing energy consumption. Multiple methods have been used for the design and improvement of chemical/biotechnological processes. Among these, shortcut methods, especially thermodynamic-topological analysis, are highlighted as a useful tool in the process engineering stage of a given process and might be useful to decrease energy consumption and to increase the efficiency since the design stage. This work proposes a design strategy for biorefineries using a shortcut method as the thermodynamic-topological analysis. For this, a biorefinery based on cocoyam, which is a rural raw material with a high potential for the obtainment of added-value products, was used as a case study. The chosen products were ethanol, lactic acid, starch, and feed additive. The biorefinery was simulated in Aspen Plus. Thermodynamic-topological analysis was implemented in the proposed biorefinery and both biorefineries (with and without the application of thermodynamic-topological analysis) were assessed in economic, environmental, efficiency, and energy-consumption terms. It was determined that the application of thermodynamic-topological analysis generated a more efficient process. After the validation of the results, it was possible to establish a design strategy for biorefineries complementing the knowledge-based approach and based on thermodynamic-topological analysis.