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Method for promoting rapid preparation of methane from organic waste by utilizing exogenous hydrogen

A technology for organic waste and methane production, applied in waste fuel, fermentation, etc., can solve the problems of unbalanced distribution, unsuitable scale, complicated operation, etc., shorten anaerobic digestion cycle, increase methane bacteria activity, and reduce CO2 concentration Effect

Inactive Publication Date: 2013-03-13
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Although there are many methods for increasing methane production reported at present, there are the following problems: 1. The promotion effect is not obvious, and some additives can only increase about 5-10% of methane due to loss or inability to distribute evenly; 2. The operation is complicated and difficult control
Although two-phase anaerobic fermentation can control the conditions of the methanogenic stage to the best, adjusting the parameters of the fermentation stage is a huge project for a device or site with a large daily processing capacity, and factors such as moisture content and temperature are affected. External weather conditions are greatly affected and are not easy to be controlled by humans; 3. The cost is high and it is not suitable for large-scale projects. For example, metal salt additives are not widely used due to the large amount required
4. Biogas backflow will also have disadvantages
Take the H formed in the previous stage 2 with CO 2 Introduced into the methanation stage, will cause H 2 Seriously insufficient

Method used

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  • Method for promoting rapid preparation of methane from organic waste by utilizing exogenous hydrogen
  • Method for promoting rapid preparation of methane from organic waste by utilizing exogenous hydrogen
  • Method for promoting rapid preparation of methane from organic waste by utilizing exogenous hydrogen

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] After simply crushing domestic waste with a moisture content of 50-60%, 12 domestic waste samples were weighed, each 0.070 kg. At the same time, sludge with a moisture content of 60-80% was prepared, and 12 parts were also weighed, each 0.030 g. Take 1 part each of domestic garbage and sludge and mix them thoroughly and put them into 200mL plastic test bottles. In this experiment, a total of 12 mixed test samples were placed in 12 test bottles, divided into 6 groups, and each group had two parallel samples. The VS content of the mixed experimental sample is about 20%, and the water content is about 65%. Introduce nitrogen to make the test bottle free of other impurity gases, seal it and place it in a constant temperature room at 37°C to simulate the anaerobic fermentation state. Add 0, 1, 3, 5, 7, 10 mL of pure H from the lower end of the test bottle under a pressure of 3.3 MPa. 2 (0mL is a blank group for comparison; since the VS content of the sample is about 20%, ...

Embodiment 2

[0024] Please see attached Figure 4 .

[0025] If acid accumulation occurs during the anaerobic decomposition of garbage, that is, the pH decreases, the rate of methane production will be greatly reduced, and the process of garbage decomposition will also be slowed down. The hydrogen addition amount was selected to be 0, 3mL and 5mL respectively, and the rest were the same as in Example 1. The solid sample was sampled in one cycle of the reaction (7-14 days), and the pH was measured by mixing the solid sample: water = 1: 3. The results are shown in Figure 4 . Depend on Figure 4 It can be seen from the pH of the system that the pH of the blank group has dropped below 6.4, and such a downward trend will greatly inhibit the activity of methanogens and hinder the decomposition of garbage and methane production. After adding hydrogen, the pH of the anaerobic fermentation process is stabilized at 6.5-7.8, which effectively prevents the accumulation of volatile fatty acids and ...

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Abstract

The invention relates to a method for promoting the rapid preparation of methane from organic waste by utilizing exogenous hydrogen. The method comprises the following steps of: mixing sludge and domestic garbage in a weight ratio of 1:(2-4), wherein the content of volatile substances (VS) in the mixture is 20 to 65 percent, and the water content is 18 to 68 percent; and performing anaerobic fermentation reaction on the mixture for a period of 7 to 14 days at the temperature of between 35 and 37 DEG C and at the pH value of between 6.5 and 7.5, and introducing exogenous pure hydrogen under the pressure of between 1.1 and 5.5MPa from the bottom of the mixture in the second day of each period, wherein the maximum daily output of the methane can reach 3.65L / kg.d when the introducing amount is 50 to 150mL H2 / kg VS, and is 2.81 times the yield of the methane when the hydrogen is not added. The concentration of the methane can be improved from 33.2 percent to 75.5 percent. The cost is low, the method is easy to operate, the problem of environmental pollution of municipal refuse and greenhouse gas is solved, and the clean energy is also provided, so that the method has good social benefit and economic benefit. The method can be widely applied to the rapid preparation of the methane from the organic waste in middle and small-sized landfill sites.

Description

technical field [0001] The invention relates to a method for using exogenous hydrogen to promote rapid methane production of organic waste, and belongs to the technical field of solid waste recycling and pollution prevention and control. Background technique [0002] With the sustainable development of the economy and the steady improvement of residents' living standards, the annual output of municipal solid waste in my country has reached 150 million tons (per capita daily output is 0.9-1.2 kg), and it is increasing at a rate of 8-10% every year. Landfill is still the main way to deal with domestic waste in most cities in my country. During the landfill process, a large amount of methane greenhouse gas will be released, with a content as high as 50-60%. In large-scale landfills, landfill gas will be collected through pipelines and special gas-collecting devices, but for small and medium-sized landfills, due to unstable gas production, low total gas volume, and low comprehen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C12P5/02
CPCY02E50/343Y02E50/30
Inventor 赵由才韩丹
Owner TONGJI UNIV