Evaluation of concentration technologies in the design of biorefineries for the recovery of resources from vinasse

This article reports a study of five designs of vinasse biorefineries that incorporate anaerobic bioreactors followed by a concentration technology such as evaporation, reverse osmosis, or forward osmosis. Different techniques of draw solution regeneration – evaporation, reverse osmosis, and membrane distillation – were also analyzed. Exergy analysis, a method that evaluates the resource conversion efficiency of systems, was used to compare the alternatives. The results indicated that among the alternatives analyzed, the combination of anaerobic digestion and reverse osmosis presented the highest exergy efficiency (62%). However, evaporators were the most feasible in terms of costs. Both alternatives are interesting and the final choice depends on the technology available and local economy. In any case, the treatment of 491.76 m3/h of vinasse (exergy rate of 60513.8 kW) to recover 70% of water could reduce external water requirement by 66% and generate 28% additional electricity for the sugarcane plant. In this case, the water recovery could represent an economy of 8,490,435.76 USD/year for the Brazilian alcohol industry. [Display omitted] •Five designs of vinasse biorefinery were evaluated by exergy analysis.•A simplified cost analysis was performed for different sugarcane industry scenarios.•Evaporators and membrane processes were compared as concentration technologies.•Water recovery could reduce 66% of the external water requirement by the industry.•Evaporators and reverse osmosis were the most suitable concentration technologies.