Effect of Organic Solvents in Separation Section of Levulinic Acid Production: Synthesis of Distillation Sequences

This work highlights the system specific characteristics encountered when considering a distillation-based separation strategy for levulinic acid (LA) and the by-product formic acid (FA) in the presence of water and water-miscible sulfolane or ?-valerolactone (GVL) solvents. Simulation using Aspen Plus® was applied to identify the presence of distillation boundary surfaces and tangent pinches resulting from the non-ideal behaviour of the mixtures in question. In the applied feed composition regions, the separation performance of the GVL solvent system in particular is limited by these restricting conditions. Minimum energy requirements for the separation of valuable components are presented as the conceptual design performance indicators, allowing the benchmarking of separation strategies. Sidedraw column configurations offer advantages in enriching the dilute valuable compounds from the feed and performing difficult separations at lower solvent quantities. This is especially advantageous for the sulfolane system where both LA and FA are intermediate-boiling.