Method for preparing ethanol by low-temperature digestion and thick mash fermentation of starch as raw material

Abstract

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 0.7ton / ton of ethanol, and steam is saved by more than 40 percent.

Description

technical field [0001] The invention relates to a method for preparing ethanol by low-temperature steaming and fermenting thick mash of starch raw materials. It belongs to the fermentation method to synthesize ethanol. Background technique [0002] In the prior art, the process of preparing ethanol from starch adopts high-temperature saccharification, liquefaction, fermentation and distillation. There are still the following problems to be solved. [0003] 1. The cooking and liquefaction process of starch requires a large amount of steam, and the amount of steam used is more than 40% of the whole process. The energy consumption is high, and the starch conversion rate is low, resulting in increased production costs. [0004] 2. It is easy to be infected with miscellaneous bacteria, resulting in unstable production. [0005] 3. The liquefied liquid has high water content and low sugar content. Affect the improvement of starch conversion rate. Contents of the invention ...

AI Technical Summary

Problems solved by technology

[0003] 1. The cooking and liquefaction process of starch requires a large amount of steam, and the amount of steam used is more than 40% of the whole process. The energy consumption is high, and the conversion rate of starch is low, resulting in increased production costs.

[0004] 2. Susceptible to infection of bacteria, resulting in unstable production

Affect the improvement of starch conversion rate