Conceptual design of a dual reactive dividing wall column for downstream processing of lactic acid

Abstract

Methodologies for designing intensified processing units are necessary to enable the industrial application of process intensification concepts. This article presents a ruled-based systematic methodology for the synthesis and conceptual design of a dual reactive dividing wall column (dual R-DWC). A decomposition approach is used to identify the tasks required for the separation by introducing a reactive separating agent to exploit a reversible reaction to enhance the driving forces. A combination of shortcut and rigorous simulations led to the conceptual design of a novel dual R-DWC in which the forward and reverse reactions and the separation occur at once.The methodology was demonstrated in a case study for the separation of lactic acid from dilute aqueous streams and a reactive impurity that hinders the lactic acid conversion and its recovery, while the byproducts may bring new challenges for the desired separations.This study is the first to investigate the effect of reactive impurities on the reaction and the separation, hence adding a more realistic framework to the design. The flowsheet produced was evaluated against benchmark processes and showed a significant process improvement in terms of energy savings (ranging 13-27 %), material intensity (28-32 % reduction), and water consumption (22-36 % reduction), while the reactive impurities are effectively removed.