Treatment method and system for waste gas and waste liquid in bio-fermentation production of fuel ethanol

Abstract

The invention discloses a treatment method and system for waste gas and waste liquid in bio-fermentation production of fuel ethanol, and belongs to the technical field of pollution treatment. The treatment method comprises the following steps: washing the waste gas with the waste liquid, absorbing SOx, NOx, H2S and NH3 in the waste gas, and reducing the conductivity and the pH value of the waste liquid, wherein the waste gas comprises sewage treatment foul gas, fermentation tail gas and marsh gas; conveying the washed sewage treatment foul gas and the washed fermentation tail gas into an oxidization furnace for treatment, and discharging the gas if the gas meets the standard; conveying the washed marsh gas into a CNG system for treatment, and recycling the treated gas; and recycling the waste liquid used for washing, filtering the waste liquid through a membrane filter device to filter out mycoproteins, recycling filtered concentrated liquid, extracting the mycoproteins, recycling filtered filtrate for preparation of a fermentation nutrient solution, and applying the fermentation nutrient solution to preparation of the fuel ethanol. According to the treatment method, the treatment load and the impact on a sewage treatment system due to the waste liquid are relieved; and the aim of treating wastes with wastes is fulfilled, and resources can be used to the maximum extent.

Description

technical field [0001] The invention relates to the technical field of pollution treatment, in particular to a method and system for treating waste gas and liquid in the production of fuel ethanol produced by biological fermentation. Background technique [0002] With the gradual enhancement of human awareness of environmental protection, people are more and more concerned about the quality of the surrounding living environment. In the production process of fuel ethanol by bio-fermentation, sulfur-containing waste gas will be produced, which contains hydrogen sulfide and other gases, which can not only cause pipeline corrosion, catalyst poisoning, equipment corrosion, but also cause serious environmental pollution. Therefore, the emission of sulfur-containing gases must be strictly controlled. In addition, a large amount of waste lye will be produced every day due to cleaning equipment. [0003] Gas containing hydrogen sulfide includes three parts: sewage treatment malodor...

AI Technical Summary

Problems solved by technology

The malodorous gas in sewage treatment is mainly the smell of hydrogen sulfide gas; X There is a risk that the content exceeds the standard. In order to meet the standard, the hydrogen sulfide content in the oxidation furnace needs to be further processed; the hydrogen sulfide content in the biogas is 0.5% to 1%, and this part of hydrogen sulfide must be removed before biogas purification.

Spent lye is the waste liquid after cleaning in place (CIP) equipment produced regularly by the factory, including lye that cannot be recycled after membrane cleaning, fermenter cleaning, and distillation tower cleaning. It produces about 30 tons per day , The main component of CIP waste liquid is 2% to 3% sodium hydroxide solution, and it also contains bacterial protein left over in the mash after fermentation. According to the previous treatment experience, it is directly discharged to the sewage treatment system. Since it is not continuously produced in a constant amount, Therefore, its high conductivity and high pH value will cause great fluctuations in the quality of treated water in the sewage treatment system with the change of waste lye discharge, and the risk of unqualified effluent is difficult to avoid

In addition, the CIP waste liquid containing bacterial protein directly enters the sewage treatment system as waste water. Because of its high suspended solids and chemical oxygen demand (Chemical Oxygen Demand, COD), the treatment is difficult and costly, and it will also produce biological sludge. Toxic effect

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