Energy, exergy and economic assessment of the introduction of VHG fermentation in conventional bioethanol production process from sugarcane

Palacios-Bereche, M.C. ; Palacios-Bereche, R. ; Gallego, A.G. ; Rossell, C.E.V. ; Serra, Luis M. (Universidad de Zaragoza) ; Lozano, Miguel A. (Universidad de Zaragoza) ; Ensinas, A.V. ; Nebra, S.A.

Resumen: Fermentation under Very High Gravity (VHG) conditions is an improved process that produces a wine with higher ethanol content, though requiring lower temperatures than conventional fermentation. Therefore, an auxiliary cooling system is required to maintain appropriate VHG fermentation conditions. Thus, the aim of this work is to evaluate—through energy, exergy, and economic assessments—the incorporation of the VHG fermentation process into a conventional ethanol and sugar production process. Three auxiliary cooling systems were evaluated: a) a vapour compression refrigeration system, b) an absorption refrigeration system, and c) an ejector cooling system. The VHG fermentation increases overall steam consumption by 1.7–5.3 % and reduces surplus electricity in the cogeneration system by 1.6–3.8 %. The case involving an ejector system showed the highest steam consumption and lowest surplus electricity; nevertheless, the global exergy efficiency remained around 44 % in all cases. Furthermore, VHG fermentation promotes a reduction in water consumption (−32 %) and in vinasse production (−60 %). Finally, the economic assessment showed that all auxiliary cooling systems presented economic feasibility for the assumed considerations; still, the ejector cooling system case presented the lowest capital cost (2.69 MMUSD) and the shortest payback (2.69 years).

Idioma: Inglés

DOI: 10.1016/j.energy.2025.138696

Año: 2025

Publicado en: Energy 337 (2025), 138696 [21 pp.]
ISSN: 0360-5442

Financiación: info:eu-repo/grantAgreement/ES/DGA/T55-23R

Tipo y forma: Artículo (PostPrint)

Área (Departamento): Área Máquinas y Motores Térmi. (Dpto. Ingeniería Mecánica)