Synthesis of Alternative Cost-Effective Process Flowsheets for Lactic Acid Valorization by Means of the P‑Graph Methodology

Valorization of productive chains based on crops is of utmost interest for countries with potential for obtaining products from agricultural resources. In this regard, this contribution explores the valorization of sugarcane through the diversification of products for one of its derivatives: lactic acid (LA). A set of chemical processes yielding valuable products, such as esters and polylactic acid, was synthesized by means of the P-graph methodology. The operating units considered were evaluated by simulation with Aspen Plus and MATLAB to estimate the profit of various flowsheets involving such units. The P-graph methodology identified the best process, with a profit of 31.9 million USD/y. In addition, the methodology identified 124 alternative processes to use LA, some of which exhibited interesting features, such as process safety or energy robustness, despite exhibiting lower profit. Methyl lactate was identified as a key product for valorization in view of the additional valuable products that are generated from it.