Method for producing ethanol by reusing anaerobic digestion effluent and refining tower residue

Abstract

The invention discloses a method for producing ethanol by reusing anaerobic digestion effluent and refining tower residue, belonging to the technical field of wastewater treatment and ethanol fermentation industry, including the steps: mixing membrane filtrate of anaerobic digestion effluent filtered through films, the residual liquid of the refining tower and the other ingredient water with the crushed grain raw materials, according to the ratio of ingredient water to the crushed grain raw materials is 1 : (2-3.5), saccharifying, fermenting and distilling to obtain ethanol, wherein that membrane filtrate accounts for 10-90% of the water mass of the total ingredient, and the residual liquid in the refining tower accounts for 1-30% of the total ingredient water, and the other ingredient water accounts for 0-60%, and that volatile acid concentration of the ingredient water is controlled at 100-1200 mg / L by adjust the proportion of the membrane filtrate, the residual liquor of the refining tower and other ingredient water or adding acetic acid (based on acetic acid), and at the same time, the alcohol yield is remarkably improve, and the utilization rate of raw materials is improve by1. 5%, reduce that energy consumption and cost of ethanol production.

Description

Technical field [0001] The invention relates to a method for producing ethanol by recycling anaerobic digestion effluent and refined tower residual liquid, and belongs to the technical field of wastewater treatment and ethanol fermentation industry. Background technique [0002] Ethanol is an important industrial raw material. It is widely used in food, medicine, chemical and other industrial fields. It is also an important renewable biomass energy (fuel ethanol) and is highly valued by governments around the world. [0003] While the ethanol industry is developing rapidly, it is also facing very prominent practical problems. That is, the production process needs to consume a lot of starch raw materials and water resources, and produce a lot of high-concentration organic wastewater (distillation waste liquid). According to statistics, at present, more than 60% of ethanol production materials in my country are corn, wheat, aged rice, and brown rice. Each ton of ethanol produced co...

AI Technical Summary

Problems solved by technology

In order to reduce the discharge of wastewater and reduce the cost of wastewater treatment, part of the distiller's grains will be directly reused in the ethanol batching process during production, but studies have shown that the reuse ratio of the distiller's grains generally does not exceed 30%, otherwise the solids in the distiller's grains, Substances such as acetic acid, lactic acid and sodium salts will accumulate and poison the ethanol fermentation yeast, resulting in lower raw material utilization

There are still two disadvantages in directly reusing distiller's grains as ingredients: one is that the distiller's grains contains miscellaneous bacteria, and the reuse of ingredients can easily lead to acid production by ethanol fermentation, which reduces the utilization rate of raw materials; It is necessary to add alkali or ammonia water to adjust the pH value to the optimum pH range of liquefaction enzyme, which increases the operation and cost

Taking ethanol fermentation with conventional mixing material concentration as an example, the ethanol concentration of the mature fermented mash is about 11-13% (v / v) after the end of fermentation. If the absolute concentration of ethanol is reduced by 0.1- 0.2% (v / v), it is difficult to detect in production, but for an ethanol production enterprise with an annual output of 100,000 tons, the economic loss caused by this slight impact is about 5 million yuan

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