VIRTUAL PILOT PLANT FOR LACTIC ACID PURIFICATION BY REACTIVE DISTILLATION PROCESS

In recent years, concerns over the microbial production of commercially valuable products have grown. This is mainly attributed to escalating global energy and environmental problems, which have stimulated researchers worldwide to develop methods for producing high added value products or even most products using green solvents and/or raw materials. Among these, lactic acid has attracted much attention due to its widespread variety of applications in synthesizing products such as bio-plastics, pharmaceuticals, food, preservatives, cosmetics and fertilizers. Esterification of lactic acid from fermentation broth and then hydrolysis of lactate ester in reactive distillation column is an effective process for purification of lactic acid. In this work, a virtual plant for lactic acid purification using two reactive distillation columns (esterification and hydrolysis columns) and a recovery section of ethanol was studied. The simulation was carried out with the aid of the Aspen Plus^TM Process Simulator. The thermodynamic properties and reaction kinetics were firstly analyzed; then the reactive distillation columns were designed based on the ethyl lactate and lactic acid purities. UNIQUAC model was used for calculating activity coefficients in order to achieve equilibrium compositions and temperatures for components of the system. The results showed that the process for lactic acid purification proposed in this work, based on fully renewable raw material, provides large potential to achieve high yield of ethyl lactate and industrial grade of lactic acid (~80 wt%).