The invention discloses a three-column two-membrane coupled reinforced refining method for fuel
ethanol. In the method, a rectification-purification process
system includes a three-column rectification section formed by connecting a decompression
distillation column and two pressurized coarse
distillation columns which adopt a mash parallel feeding manner, and a purification section includes a membrane separation device. Materials of the rectification section and the purification section are highly matched with a heat
system to reduce steam consumption for a unit product; through combination of vapor
permeation and membrane separation, the concentration requirement of fed
ethanol is reduced, the number of column trays of the pressurized coarse
distillation columns is reduced, and the
reflux ratio is reduced, so that
biomass fermented mash is rectified and purified to prepare high-purity
ethanol meeting the requirement of fuel ethanol, and the production purposes of
environmental protection,
energy conservation and high efficiency are achieved. The method disclosed by the invention has the advantages of greatly saving steam consumption, being high in one-time discharging quality, high in
system automation degree, small in occupied area of the device, convenient to maintain equipment, reliable and durable in membrane consumable material, high in
resource utilization rate and thelike.