Özet:

Thermo-economics analysis was used to identify the most economic distillation hybrid configuration to dehydrate bioethanol mash (12 wt%) to fuel grade (99.5 wt%) based on economic objective of minimization of operating cost in this work. Three different hybrids of THIDC with azeotropic and, extractive distillation units were assessed using similar feed and product specifications of 1200 kmol/h (12 % by weight ethanol) and 55 kmol/h (99.5 % by weight ethanol) respectively . The six hybrid configurations were simulated using Aspen Plus ®. The hybrid of THIDC with conventional extractive distillation (THEX1) was shown to have the lowest irreversibility rate (lost work) and highest exergetic efficiency followed by the hybrid containing thermally extractive sequence (THEX3). The latter also has the lowest energy consumption. However, economic evaluation showed that thermally coupled extractive distillation hybrid (with THIDC) is the most attractive hybrid configuration dehydrating bioethanol to fuel grade at commercial scale with the highest return on investment (ROI) and the least annual product cost. This indicates its economic attractiveness when compared with the other hybrids considered in this work. The trade-off existing between economic and exergy efficiency favours the selection of THEX3 as the preferred choice for bioethanol refining among all the six hybrids investigated.

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