| 摘要 |
It is an object of the present invention to provide a method for producing ethanol by alcohol fermentation of a saccharide obtained by hydrolyzing cellulosic biomass in a supercritical or subcritical state, wherein excessive decomposition and caramelization of the saccharide are inhibited to prevent a reduction in yield of the saccharide, and flash steam is effectively used. The method for producing ethanol using cellulosic biomass as a raw material of the present invention is characterized in that in a saccharification/decomposition step, a slurry after saccharification/decomposition, which is taken from a hot water reaction vessel such as a pressure vessel, is flash-evaporated in a first flash tank so as to have a temperature of 150°C to 200°C (inclusive), and the retention time of the slurry after saccharification/decomposition is set at 3 minutes or less; the slurry after saccharification/decomposition, which is taken from the first flash tank, is further flash-evaporated in a second flash tank so as to have a temperature of 100°C to 120°C (inclusive); and first flash steam generated from the first flash tank is used as a heat source in the saccharification/decomposition step or a distillation step. |
