Multi-criteria Single-Objective Optimization of a Glycerol Valorization Process Aiming at Solketal Production

Global biodiesel production follows a growing trend, producing large volumes of glycerol, a low-value-added product. In this context, this work aims to evaluate the technical and economic viability of solketal production on an industrial scale through the glycerol ketalization reaction, to valorize the biodiesel chain coproducts and increase the economic sustainability of biodiesel biorefineries. The process was simulated with the Aspen Plus V.12.1 simulator, and the purification system was optimized through an enhanced Scatter Search algorithm from the MEIGO add-on in MATLAB® R2022a software. Three optimization scenarios were evaluated in this work: minimizing the CO₂ emission, minimizing the utility cost, or maximizing the solketal yield, with different constraints on the single-pass glycerol conversion. An economic analysis of the most promising case study was developed, varying the internal rate of return, reactant costs and solketal selling price. The economic analysis showed that the minimum solketal selling prices ranged from 1847.29 to 1966.27 US$/t. It also indicated that the methodology adopted for the optimization step could be beneficial to increase the profitability of the simulated plant, as most economic scenarios were feasible if a solketal selling price of approximately 1920 US$/t were considered.