Method for preparing biogas through anaerobic digestion of sludge and obtained biogas

An anaerobic digestion and sludge technology, applied in biological sludge treatment, pyrolysis treatment of sludge, special forms of dry distillation, etc., can solve the problems of incomplete degradation of organic matter, long anaerobic digestion cycle, and large equipment area. , to achieve the effect of promoting circular economy, realizing resource utilization and reducing floor space

Pending Publication Date: 2021-04-20
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, anaerobic digestion has two disadvantages: one is the longer residence time, because the production of methane from hydrogen is an interspecies electron transfer process from fatty acids or fatty alcohols to carbon dioxide (interspecies electron transfer), which relies on diffusive electron carriers (Hydrogen or formate) mediation, the rate is slow, so the anaerobic digestion cycle is long, and the equipment occupies a large area; the second is that the organic matter is not completely degraded, usually only about 40 to 60% of the organic matter in the sludge can be anaerobic. It is converted into biogas during the digestion process, and the digested sludge still contains a large amount of organic matter that is difficult to biodegrade, and still has a high potential for energy utilization, so the energy can be recovered by thermochemical methods
At present, there are no related reports on the use of this method to strengthen anaerobic digestion of sludge to produce biogas

Method used

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  • Method for preparing biogas through anaerobic digestion of sludge and obtained biogas
  • Method for preparing biogas through anaerobic digestion of sludge and obtained biogas
  • Method for preparing biogas through anaerobic digestion of sludge and obtained biogas

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preparation example Construction

[0029] Wherein, the preparation method of described biochar comprises:

[0030] (1) Digesting the sludge raw material under airtight and anaerobic conditions to obtain the first digested sludge;

[0031] (2) crushing the first digested sludge after filtering and drying to obtain the second digested sludge;

[0032] (3) obtaining the first product after pyrolyzing the second digested sludge;

[0033] (4) After boiling the first product in an acid solution, the pH is adjusted to be neutral, and the solid obtained after drying is the biochar.

[0034] Wherein, the sludge raw material in step (1) includes fresh sludge and inoculated sludge or the sludge raw material includes fresh sludge, inoculated sludge and biochar.

[0035] Wherein, the mass ratio of fresh sludge and inoculated sludge described in step (1) is 1: (0.15 to 0.25);

[0036] Wherein, the temperature of the digestion reaction described in step (1) is 30 to 40 degrees Celsius; the digestion time is 18 to 23 days; ...

Embodiment 1

[0055] (1) The sludge used in this example comes from a sewage treatment plant in Tianjin. The moisture content of the sludge is 90.23%. After adjusting the moisture content to 95.0%, an anaerobic digestion experiment is carried out. The elemental analysis and industrial analysis of the sludge are as follows :

[0056] Table 1 elemental analysis (%)

[0057]

[0058] Table 2 Industrial Analysis (%)

[0059]

[0060] Among them, the fixed carbon* in Table 2 is calculated by subtraction method

[0061] (2) In this embodiment, the temperature of anaerobic digestion is 36 degrees Celsius, the volume of the digestion reactor is 1000 ml, the volume ratio is 0.8, and the inoculated sludge ratio is 0.2. Such as figure 1 As shown, the specific operation steps are as follows:

[0062] ① Take 640ml of fresh sludge 1 and 160ml of inoculated sludge into anaerobic digestion reactor 2 respectively, put a rotor into it, and pass nitrogen gas for 5 minutes to remove oxygen in the hea...

Embodiment 2

[0074] The pyrolysis and anaerobic digestion systems and raw materials used in this example are the same as those in Example 1, and will not be described in detail. The difference is that the number of digestion days in this embodiment is 5 days.

[0075] This embodiment is carried out for 5 days, the gas production of the experimental group is 171.05 milliliters, the gas production of the blank group is 136.9 milliliters, the gas production of the experimental group has increased by 24.94% relative to the blank group; the methane content of the biogas of the experimental group is 39.33%, and the methane in the biogas of the blank group The content is 34.23%, and the biogas methane content of the experimental group has increased by 14.99% compared with the blank group.

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Abstract

The invention relates to a method for preparing biogas by anaerobic digestion of sludge and the obtained biogas, and the method comprises the step of carrying out digestion reaction on fresh sludge, inoculated sludge and biochar under a closed anaerobic condition to obtain the biogas and first digested sludge. The method for preparing the biochar by pyrolyzing the digested sludge, provided by the invention, is simple to operate and low in cost, and the prepared biochar has a good effect of enhancing anaerobic digestion to produce biogas; the method is also beneficial to reducing the environmental pollution problem of the sludge, and can realize the resource utilization of the sludge.

Description

technical field [0001] The invention belongs to the field of organic solid waste treatment and resource utilization, and in particular relates to a method for preparing biogas by anaerobic digestion of sludge and the obtained biogas. Background technique [0002] In recent years, the scale of China's sewage treatment plants has gradually expanded, and the sludge output has increased dramatically. According to statistics from the Ministry of Housing and Urban-Rural Development, China's sludge production in 2017 has reached 3.62×10 7 Ton. Sludge has a complex composition and contains various substances such as organic matter, heavy metals, and pathogens. If it is not handled properly, it will cause adverse effects on the ecological environment. Therefore, sludge disposal cannot be ignored. [0003] At present, the sludge treatment methods mainly include anaerobic digestion, incineration, pyrolysis, gasification, etc. Among them, anaerobic digestion is a relatively mature te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/04C02F11/10C10B53/00C10B57/10
Inventor 陈冠益张蕊颜蓓蓓
Owner TIANJIN UNIV
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