Integration of COSMO-based methodologies into commercial process simulators: Separation and purification of reuterin



The conceptual design of a new process is developed via computer-aided simulation for separating and purifying reuterin, an antimicrobial substance obtained by bacterial fermentation of glycerol, from its mixture with the nonfermented substrate, the main subproduct of the process (1,3-propanediol) and water. The nondatabank components included in the simulations are created by using the structures derived from quantum mechanical calculations and the properties (molecular weight, normal boiling point, and mass density) estimated by COSMO-RS method. The unknown remainder properties are estimated by the methods and models used by default in Aspen Plus (v7.3). The COSMOSAC property model, also implemented in Aspen Plus, is specified with the molecular volumes and sigma profiles obtained by COSMO-RS. The properties (boiling temperatures, densities, VL equilibria, etc.) predicted for glycerol, 1,3-propanediol, water, and their mixtures by COSMO-based methods agree reasonably well with experimental reported values, whereas those obtained for reuterin derivatives are consistent with the behavior of amphoteric compounds having strong capabilities to interact attractively with hydrogen donor and acceptor groups all together. The process consists of a two-stage distillation operation, the first of which removes the water and the second one separates reuterin as a 99.5 wt %-pure bottom product. The second column operates at low pressure (ca. 40 kPa) to avoid thermal decomposition of reuterin (over 280°C) and guaranties 99.9% recovery of the desired product. Water removing offers different heat integration and energy-saving opportunities considering that condenser pressure of the first column can be increased to ∼15 bar preserving the thermal integrity of the reuterin. Dimensions of the equipments as well as capital and operating costs are evaluated. © 2012 American Institute of Chemical Engineers AIChE J, 2012