(587f) Reducing Energy, Solvent, and Resin Demand of Sorption-Based Processes for Carboxylic Acid Recovery

Authors: 
Saboe, P., NREL
Manker, L., National Renewable Energy Laboratory
Monroe, H., NREL
Michener, W., National Renewable Energy Laboratory
Haugen, S., National Renewable Energy Laboratory
Beckham, G. T., National Renewable Energy Laboratory
Karp, E. M., National Renewable Energy Laboratory
Current methods such as ion exchange and distillation to separate bio-based carboxylic acids are material and energy intensive, typically generating waste streams and requiring energy intensive distillation steps to recover a pure product. Sorption-based approaches increase the sustainability of carboxylic acid separations by reducing downstream waste handling, however, current sorption-based technologies typically require large volumes of elution solvent and still result in a dilute carboxylic acid stream. Thus, to obtain a concentrated product, excess water and solvent must be removed from the elution stream via evaporation or distillation which adds a substantial operational cost to the process. This presentation will discuss recent work towards reducing solvent, adsorbent requirements and reducing downstream distillation energy demands in these processes. Specifically, four commercially available weak-base resins were screened by determining their adsorption capacity for butyric acid, a fermentable acid targeted for biofuels. Then, to recover the adsorbed acid, non-aqueous solvents were tested and their regeneration constant were determined. Findings indicate that specific properties of the resins and eluents correlate with the energy, resin, and solvent demands of the system. These results provide a general framework for optimizing sorption-based processes for recovering dilute bioproducts.