Method for producing ethanol by fermenting sweet sorghum juice through yeast refluxing method

Abstract

The invention discloses a method for producing ethanol by fermenting sweet sorghum juice through a yeast refluxing method, wherein sweet sorghum is squeezed to extract juice, and then the extracted juice is fermented; and the yeast used in the method is candida tropicalis ZXNY-1, and the collection number is CGMCC No.3889. In the method, before mature fermented mash is distilled, the yeast in the mature fermented mash is separated by a disc separator under normal temperature, the separated yeast is soaked with dilute acid solution, and then the soaked yeast is reused in a first fermentation tank so as to increase the number of the yeast; the yeast is already mature, so sugar in the juice is basically not consumed by the yeast, but sugar-ethanol transformation can be performed, thus achieving greatly reduced yeast usage, less sugar consumption of sugar liquor as a raw material, yeast concentration over 0.4 billion / ml in fermented mash liquid and realized short-time, high liquor content and low sugar consumption fermentation of the sweet sorghum juice; and the liquor content in the fermented mash liquid is more than 14% (v / v), the total residual sugar content is less than 0.55%, the sugar conversion rate is more than 90% and the fermentation time is not more than 22 hours.

Description

technical field [0001] The invention relates to a method for producing ethanol, in particular to a method for producing fuel ethanol by fermenting sweet sorghum juice with yeast reflux method. Background technique [0002] Fermentation is the key to the production of ethanol by microbial method. It directly determines various important indicators such as raw material consumption per ton of ethanol, utilization rate of fermentation equipment (that is, investment in fermentation equipment), energy consumption required for later distillation, and wastewater discharge at the bottom of the tower. [0003] The length of ethanol fermentation time, the concentration of ethanol in the fermentation mash and the quality of sugar consumption are directly related to the amount of yeast in the mash. Usually, the number of fermenting yeast is controlled below 180 million / ml. The main reason is that if the number of yeast is too large, the yeast itself will consume too much sugar for value-...

AI Technical Summary

Problems solved by technology

Usually, the number of fermenting yeast is controlled below 180 million / ml. The main reason is that if the number of yeast is too large, the sugar consumption of the yeast itself will be too much, resulting in the high raw material consumption per ton of ethanol and the long fermentation time.

[0004] In the existing method of using sweet sorghum to ferment ethanol, it is necessary to continuously supply fermenting yeast during the fermentation process, so that the amount of yeast used is too large and the production cost is too high

Due to the single performance and poor activity of existing commercially available yeast, it is not suitable for repeated use

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