Method for producing marsh gas by two-phase dry-type mixed anaerobic fermentation

A technology for anaerobic fermentation and biogas production, applied in the fields of fermentation, biosynthesis, waste fuel, etc., it can solve the problems of harsh conditions for microbial activity, slow industrialization progress, easy acidification, etc., to alleviate the problem of acid inhibition and enrich the theory , the effect of increasing methane production

Active Publication Date: 2014-12-03
UNIV OF SCI & TECH BEIJING
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  • Abstract
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AI Technical Summary

Problems solved by technology

However, the theory of anaerobic dry fermentation of perishable organic waste (such as kitchen waste, etc.) is relatively lacking, and the industrialization progress is slow. The main reason is that with the decrease of water content, many conditions affecting microbial activity become more harsh.
Among them, the acidification of the fermentation system caused by the accumulation of volatile fatty acids, thereby inhibiting the activity of methanogens is particularly prominent (the optimal pH for the growth of methanogens is 6.8-7.2), especially for dry fermentation of easily degradable organic waste such as kitchen waste. Very prone to acidification in the early stage
Therefore, the development of a dry-type anaerobic biogas production process for perishable food waste with high salt content and high oil content is of great significance to solve the problem of acid inhibition in the fermentation of food waste.

Method used

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  • Method for producing marsh gas by two-phase dry-type mixed anaerobic fermentation
  • Method for producing marsh gas by two-phase dry-type mixed anaerobic fermentation
  • Method for producing marsh gas by two-phase dry-type mixed anaerobic fermentation

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Put the food waste into an ethanol pre-fermentation tank after being crushed, add dry yeast with a mass of 5‰ of the dry weight of food waste (calculated as VS), and carry out 12 days under the condition of temperature 30±1℃ and anoxic. ~72 hours of ethanol pre-fermentation, and then the food waste and distiller's grains are uniformly mixed at a mass ratio (calculated as VS) of 1:1 to 0.21:1, and the sludge is inoculated and fermented to produce biogas, wherein the inoculation ratio ( Inoculation sludge: Fermentation raw material (food waste + distiller's grains)) is 1:1 (calculated as VS, w / w). 339mL / (d·L). The result is as figure 2 shown, from figure 2 It can be seen that compared with the control group without pre-fermentation, regardless of the mixing ratio of food waste and distiller's grains, the gas production, ethanol concentration, and volatile fatty acid VFA concentration of the ethanol pre-fermentation group were higher , thereby shortening the acid inhi...

Embodiment 2

[0036] According to Example 1, after 72 hours of ethanol pre-fermentation of the food waste, the food waste and distiller's grains were evenly mixed at a mass ratio of 0.56:1 (calculated as VS), and the sludge was inoculated and fermented to produce biogas. The ratio (inoculation sludge: fermentation raw material (food waste + distiller's grains)) is 1:1 (in terms of VS, w / w). The result is as image 3 shown, from image 3 It can be seen from the figure that the difference between the experimental group and the control group through ethanol pre-fermentation is obvious by comparison. The concentration of propionic acid in the experimental group after ethanol pre-fermentation is 59% lower than that of the control group, and the ethanol concentration is 24% higher than that of the control group. %, alkalinity increased by 27%, pH increased by 9%, and methane production increased by 29%. The results well indicate that after ethanol pre-fermentation, the buffering capacity of the...

Embodiment 3

[0038] According to Example 1, the food waste was subjected to ethanol pre-fermentation for a period of 72 hours, and the food waste and distiller's grains were evenly mixed at a mass ratio of 0.21:1 (calculated as VS), and the sludge was inoculated and then fermented to produce biogas. The inoculation ratio (inoculation sludge: fermentation raw material (food waste + distiller's grains)) is 1:1 (calculated as VS). The result is as Figure 4 shown, from Figure 4It can be seen that the concentration of propionic acid in the experimental group after ethanol pre-fermentation decreased by 30.0% compared with the control group, the concentration of ethanol increased by 25.3%, the alkalinity increased by 25.5%, the pH increased by 14.5%, and the methane production increased up 26.7%.

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Abstract

The invention provides a method for producing marsh gas by two-phase dry-type mixed anaerobic fermentation, belonging to the technical field of renewable energy sources. The method mainly comprises the following steps: ethanol prefermentation: inoculating a certain amount of dried yeast into kitchen waste to carry out ethanol prefermentation; and methane fermentation: mixing the kitchen waste subjected to ethanol prefermentation and vinasse in a ratio of 1:1 (on the basis of VS) as a substrate for subsequent anaerobic fermentation, and inoculating long-term acclimatized sludge in a ratio of 1:1 (sludge:substrate (on the basis of VS)). The method searches the possibility of optimizing methane anaerobic fermentation by ethanol prefermentation, and optimizes the experimental conditions for ethanol prefermentation. The method can effectively relieve the problem of volatile acid inhibition in the anaerobic digestion process, and obviously enhances the methane yield, thereby enhancing the energy recovery rate. The method is simple to operate, and thus, has high practical value.

Description

[0001] technical field [0002] The invention relates to the technical field of renewable energy, in particular to a method for producing biogas by two-phase dry mixed anaerobic fermentation. [0003] Background technique [0004] Energy shortage is one of the major problems facing this century. Among the many clean energy sources, various bioenergy (ethanol, biogas, hydrogen, biodiesel, etc.) produced from biomass have received extensive attention. Bioenergy is a typical low-carbon fuel, which can greatly reduce greenhouse gas emissions. Organic waste (such as kitchen waste, etc.), crops, trees and other plants and their residues (such as agricultural straw, etc.), livestock and poultry manure can all be used as fermentation materials for bioenergy. With the acceleration of urbanization and the improvement of people's living standards, the amount of kitchen waste generated is increasing. [0005] Food waste is mainly composed of starch, dietary fiber, animal fat and othe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12P5/02
CPCY02E50/30Y02P20/59
Inventor 汪群慧张笑于淼宋娜王利红孙晓红
Owner UNIV OF SCI & TECH BEIJING
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