Wood fiber raw material pretreatment method for producing fuel ethanol

The invention discloses a wood fiber raw material pretreatment method for producing fuel ethanol. The pretreatment method comprises the following steps: adding sulfonating cooking liquor in a wood fiber raw material, heating and boiling through microwave in an ultrasonic environment, and pre-reacting under a boiling state to obtain a primary cooking material; sulfonating the primary cooking material under 100-120KPa and at 110-130 DEG C to obtain a secondary cooking material; filtering the secondary cooking material, adding a sodium acetate buffer solution to a filter residue, and performing a hydrothermal reaction under 100-120KPa and at 110-130 DEG C to obtain a ternary cooking material, thereby finishing pretreatment. The sulfonating reaction is enhanced by virtue of microwave and ultrasound, so that sulfonating temperature is reduced for more than 40 DEG C compared with that of a conventional method; the method is mild in reaction condition and can be used for preventing cellulose from being degraded. By replacing water with the sodium acetate buffer solution, the temperature of the hydrothermal reaction is reduced by more than 40 DEG C compared with that of the conventional method; therefore, the method can be used for reducing the energy consumption, guaranteeing mild reaction conditions, and reducing generation of enzymolysis or fermentation inhibitor.