The invention discloses a method for preparing
ethanol by low-temperature
digestion and thick mash
fermentation of
starch as a
raw material, belonging to the field of
ethanol synthesis with a
fermentation method. The method adopts a process of low-temperature
digestion for liquefying and thick mash
fermentation and comprises the following operation steps of: a, cleaning and crushing raw materials, b, precooking to prepare
powder slurry, c, digesting at low temperature for liquefying, and d, saccharifying, fermenting and distilling. The method for preparing the
ethanol by low-temperature
digestion and thick mash fermentation of
starch as the
raw material has the advantages of low
water content and
high sugar degree in a liquefied solution, low
energy consumption, high yield, stable production and lower cost. The low-temperature digestion for liquefying ensures that total
sugar content in the liquefied and pasted solution is not less than 25 percent, the thick mash fermentation ensures that
ethanol content in fermented mature mash reaches 18 percent, the
starch conversion rate is not less than 53 percent, and moreover, steam consumption amount is not larger than 0.7
ton /
ton of ethanol, and steam is saved by more than 40 percent.