Fuel-based ethanol dehydration process directly extracted by gasoline additive

• Dehydration of bio-ethanol with gasoline additive MTBE as entrainer is proposed.
• The product of mixture of ethanol and MTBE can be mixed directly with gasoline.
• Residue curve maps are applied for process conceptual design.
• The dehydration process can significantly reduce the energy consumption.

To reduce the heavy energy consumption of the conventional dehydration process of bioethanol production from biomass fermentation broth, this work aims to develop a fuel-based ethanol dehydration process directly extracted by gasoline additive. Methyl tert-butyl ether (MTBE) is screened and validated as an available entrainer of heteroazeotropic distillation from gasoline additives by analyzing and determining residue curve maps on the basis of simulation and experimental method. Two fuel-based ethanol separation processes with MTBE as entrainer, i.e. direct-cycle scheme and three-column scheme, are proposed and optimized by using ASPEN PLUS. It indicates that the proposed dehydration process with MTBE as entrainer can significantly reduce the energy and entrainer consumption, and the product can be directly used in gas pool. The techno-economic evaluation indicates MTBE scheme with 8000 ton/year ethanol production presents lower capital and utility costs than isooctane scheme.

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