Carboxylates produced by the acetogenisis fermentation of pre-treated lignocelluloses are precursors to bio-based products that are alternatives to second-generation biofuels for biomass valorization. This paper compares the techno-economic indicators for recovering either mixed ketones or mixed...

Carboxylates produced by the acetogenisis fermentation of pre-treated lignocelluloses are precursors to bio-based products that are alternatives to second-generation biofuels for biomass valorization. This paper compares the techno-economic indicators for recovering either mixed ketones or mixed volatile fatty acid (VFA) products from the carboxylates in a fermentation broth through process simulation and financial modeling. This study considers scenarios for (i) an efficient process for ketone production (K-P) involving dehydration, thermal conversion, and condensation already established in the literature; (ii) VFA production (VFA-P) with conventional methods of carboxylate acidification and separation; and (iii) advanced VFA acidification and separation methods. In conventional acidification, using mineral acids and calcium alkalis results in wastes; while in advanced acidification, the acids and bases are regenerated. Conventional separation relies on ethyl-acetate extraction, while advanced separation relies on amine extraction. Scenarios are compared in terms of energy and chemical use, and the internal rates of return (IRR) determined with price ranges assumed for mixed VFAs and mixed ketones. Thus, with optimistic product prices, K-P and VFA-P with conventional acidification-separation have indentical IRRs at 35%, but K-P is favorable due to the chemical-intensiveness and waste generation of the VFA-P. Using advanced acidification and separation could possibly improve the IRR of VFA-P to 39%, with a capital investment of 2% above that of K-P, which was estimated at US$ 293 million. Otherwise, a previously patented scheme that integrated acidification and separation based on amine complexation could also produce a VFA process that is environmentally and economically feasible

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