A method for producing ethanol from grain

Abstract

The invention discloses a method for producing ethanol by using grain as a raw material, and belongs to the technical field of waste water treatment and ethanol fermentation industry. In the present invention, the anaerobic digestion effluent is mixed with the membrane filtrate after membrane filtration, the residual liquid of the refining tower, partly sterilized distiller's grain clear liquid and other mixing water and the pulverized grain raw material, and then undergoes liquefaction, saccharification and fermentation , distillation and other processes to obtain ethanol, among which, the membrane filtrate accounts for 40-90% of the total batching water quality, the fine tower residue accounts for 1-15% of the total batching water quality, and the distiller's grains accounts for 1-30% of the total batching water quality , and the rest is mixing water. By adjusting the ratio of membrane filtrate, refining tower residual liquid, distiller's grains clear liquid and other mixing water, or adding acetic acid, the volatile acid concentration of the mixing water is controlled at 100-1200mg / L. The method of the invention greatly reduces the discharge of ethanol production wastewater, saves water resources, effectively avoids the problem of ethanol fermentation acid generation, significantly improves the alcohol yield, improves the utilization rate of raw materials by 1-5%, and reduces the energy consumption and energy consumption of ethanol production. cost.

Description

Technical field[0001]The invention relates to a method for producing ethanol using grains as raw materials, and belongs to the technical field of wastewater treatment and ethanol fermentation industry.Background technique[0002]Ethanol is an important industrial raw material, which 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]Ethanol is one of the most important bulk fermentation products in my country's fermentation industry. In 2017, there were 131 ethanol producers above designated size in the country, with a total output of 8.3 million tons, ranking third in the world. In September 2017, 15 ministries and commissions including the National Development and Reform Commission, the Energy Administration, and the Ministry of Finance jointly issued the "Implementation Plan on Expanding Biofuel Ethanol Production and Promoting the Use of E...

AI Technical Summary

Problems solved by technology

[0007] 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 low 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 mature fermented mash is about 11-13% (v / v) after 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 may reach about 5 million yuan

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