What Is a Biogas Generator?

Biogas, as the name suggests, is the gas in a marsh wetland. People often see bubbles in the marshes, sewage ditches or septic tanks. If we paddle a match, we can ignite it. This is the biogas that naturally occurs in nature. From a scientific definition point of view, biogas is a kind of combustible gas produced by various microorganisms under the condition of isolated air (reduction conditions) and at a suitable temperature and pH value through the fermentation of microorganisms. Biogas is a secondary energy source and is a renewable energy source.

Biogas is organic matter in

The main component of biogas is methane. Biogas from 50% -80%

Biogas was discovered by the Italian physicist A. Volta in the Everglades in 1776. In 1916, the Russian B.. Omelyansky isolated the first methanogen (but not a pure breed). China successfully isolated methane sarcocystis for the first time in 1980. Nearly 20 strains of methanogens have been isolated in the world.

The process of biogas bacteria decomposing organic matter to produce biogas is called

The types of biogas fermentation in rural areas are based on raw materials and feeding methods. Two kinds of fermentation methods, such as straw-based one-time feeding and continuous feeding based on poultry manure, are often used. Here is an example of the latter method. The average family in rural China should build 6 cubic meters of hydraulic pressure biogas digester, and the effective volume of fermentation is about 5 cubic meters. Due to the different dry matter content of different types of livestock and poultry manure, pig manure is used as an example to calculate how to prepare biogas fermentation raw materials. The dry matter content of pig manure is about 18%, and the fermentation concentration in the south should be about 6%. You need 1200 kg of pig manure, 500 kg of inoculum prepared (depending on the dry matter content of the inoculum and pig manure), and 3300 kg of water ; Fermentation concentration in the north should be about 8%, about 1700 kg of pig manure, 500 kg of prepared inoculum, and 2800 kg of clear water. During the fermentation process, the biogas digester is repaired with the pigpen and toilet, and can be replenished by itself material.

Preparation of biogas fermentation inoculum, rural biogas fermentation inoculum generally uses the fermentation liquid of the old biogas tank to add a certain amount of human and animal manure. For example, to prepare 500 kg of fermented inoculum, generally add 200 kg of biogas fermentation broth and 300 kg of human and animal manure, mix it in a water-tight pit and seal it with a plastic film, and use it as an inoculum after 1 week. If there is no biogas fermentation liquid, you can use 250 kg of slaughter sludge in the more fertile rural areas, and add 250 kg of human and livestock manure for about 1 week. If there is no sludge, you can directly use 500 kg of human and livestock manure for closed pile. Can be used as biogas fermentation inoculum.

Use of technology

Biogas has a long history as an energy source. China's biogas was initially mainly used in rural household biogas digesters. In the early 1970s,

GB / T 3606-2001 medical biogas stove

GB / T 4750-2002 Household Atlas

GB / T 4751-2002 Quality Inspection and Acceptance Specification for Household Biogas Digesters

GB / T 4752-2002 Regulations for the construction and operation of domestic biogas digesters ^[9]

In the operation and management process of farmers using biogas or biogas digesters, the most common problems are summarized in the following three aspects:

First, the user lacks knowledge of the operation and management of biogas digesters, and cannot guarantee the normal and continuous use and use of biogas;

Second, users have weak self-inspection, maintenance, and repair capabilities for biogas supporting equipment such as cookers;

Thirdly, some farmers have insufficient understanding of the changes and benefits brought by biogas to their lives.

Specific manifestations and troubleshooting methods of common problems

1. Fermented material is acidic or alkaline. The biogas digester normally produces gas, and the required pH of the feed liquid is between ph = 6 ~ 8, all of which can produce gas, with the highest gas production at ph = 6.8 ~ 7.5. The easiest way to distinguish is to observe with your eyes. When the material liquid in the biogas tank is slightly bluish, it indicates that the material liquid is acidic; if a white cloud appears on the material liquid, the material liquid is alkaline Already. a. When the material liquid is found to be acidic, take 3 ~ 4 kg of lime and mix it with 4 ~ 5 buckets of clean water, stir it thoroughly before pouring it into the pool from the feed port and stir it to make the lime clarified liquid and the pool The material liquid is in full contact. b. When the feed liquid is alkaline, pour the urine of pigs or cows with green weeds that have been made into 2 to 3 cm in length and pile them up outside the pond for 2 to 3 days, and then put them into the pond from the feed port. Mix and stir well to make the newly added green weeds fully contact with the feed liquid in the pond, so that it can return to normal as soon as possible.

2. For a long time, pig manure is used as the fermentation raw material of the biogas digester, but the gas pressure is high but the ignition or burning time is short. The traditional pig-raising habit is mainly to feed pigs with grain. The content of carbon-nitrogen ratio in pig manure is C: N = 13: 1, and when all other conditions are available, the content of carbon-nitrogen ratio C: N = 25 ~ 30: 1 can guarantee normal gas production, so there will be no wait. A. Add 1 square cow dung to the biogas digester every spring and autumn. B. In the normal feeding process, add an appropriate amount of carbon-rich raw materials, such as: residues of crops such as bran, husks, and broken straw.

3. Sufficient raw materials for fermentation or normal fermentation of feed liquid, but insufficient gas production. The reason for this problem is: the fermentation feed liquid forms a precipitate in the tank or the surface of the feed liquid forms a crust. The solution is: Persistently stirring the biogas digester liquid.

4. Leakage in biogas digester and gas pipeline. There are many cases of gas leakage in the biogas: a. There is no gas leakage in the gas transmission pipeline, etc., but the air pressure does not rise and the pressure is lowered by more than one after artificial pressure, and the fermentation room of the biogas tank leaks. Remove the surface sealant and repaint it 2 to 4 times before repainting the sealant. b. There are air bubbles in the water sealing ring or the sealing glue becomes black, and the sealing cap leaks air. Reseal the cap, fill the water seal ring with water, and ensure that the water seal ring has water for a long time. c. The room where the biogas is installed can smell the smell of rotten eggs or sulfur, the gas transmission pipeline, the switch leaks, or the seal cover of the 'U' pot of the purifier is broken. Use the detergent powder to find the air leak and replace the damaged parts. d. You can smell the smell of rotten eggs only when cooking or lighting, and the desulfurizer is invalid. Replace the desulfurizer in the purifier.

Feasible advice

1. Strengthen the professional knowledge and skill training for biogas users, especially train a group of amateur farmers' biogas technicians as soon as possible;

2. We must use rural rallies and horns, radio, television and other methods and methods to make extensive and in-depth publicity on the significance and role of biogas promotion and application, the construction process and subsidy policies of biogas digesters;

3. For biogas users, it is necessary to ensure the normal use of gas and adhere to long-term animal husbandry as the basis. Biogas digesters are like small factories. Without raw materials such as animal manure, new products such as biogas and biogas can not be produced.

4. "Three minutes to build a pool, seven minutes to manage and protect", which shows that the use of biogas digesters focuses on management, and adherence to frequent stirring is the key;

5. Persist in the search for biogas users, timely discover non-gas producing biogas tanks, and troubleshoot.

6. The human waste generated from the resident's bathroom every day is treated in a centralized manner to produce biogas to build biogas pipelines for residents to use, just like liquefied gas pipelines.

7. Biogas liquefaction refining technology. Biogas is a mixed gas whose main components are methane (CH4) and carbon dioxide (C02). Methane accounts for 60% to 70%, carbon dioxide accounts for 30% to 40%, and there are combustible gases such as hydrogen, carbon monoxide, hydrogen sulfide, oxygen, and nitrogen. As long as the gas separation technology is used to convert carbon dioxide into dry ice for other industrial uses, it does not require much cost to use zero-point compression to liquefy the form, and the refined combustible gas is compressed to a liquefied state. Manufactured in the form of steel cylinders to replace liquefied gas for residents.

8. Comprehensive cost saving can build a biogas treatment station that produces sewage in the toilets of residents in urban communities. On the one hand, it is made in the form of a cylinder, and on the other hand, a biogas transmission pipeline is constructed. Like a liquefied gas pipeline, urban liquefied gas needs to be sent to the west and east. A lot of cost money. A green agricultural production base is built around it, and the biogas slurry can be made into raw materials for soilless agriculture, and the biogas residue is directly processed into organic fertilizer.

First, prevent empty pools, prevent the walls of the pools from being too dry, and protect the walls of the pool from moisture. The biogas digester built is generally concrete, and cement is a porous building material. If the biogas digester is empty in the summer and encounters high temperature and dry environment, it is easy to open the capillary pores of the cement and damage the structure of the pond wall. Leak. Therefore, in the summer, the biogas digester should be eliminated. Even when the biogas digester is deactivated, the biogas digester must be filled with water to protect the pool wall and prevent the wall from cracking.

Second, the inlet and outlet openings prevent excessive rainwater from flowing in. There is a lot of rain in summer. It is necessary to prevent the rainy season at the inlet and outlet. Most of them are built outside the shed. In addition, the sealing of the inlet and outlet is not very good. Once too much rain enters the pond, it will affect the normal fermentation concentration. , Will slow down the generation rate of slow biogas, affecting the normal use of biogas digesters.

Third, the summer temperature is high, the fermentation speed is fast, and the biogas production is large. Pay attention to the pressure gauge at all times and exhaust in time to prevent safety accidents caused by excessive tank pressure. If the pressure becomes larger than the pointer 12 or higher, the gas should be deflated in time to prevent the pipe from cracking and the barometer from being damaged. In the summer, the gas production is fast, and the biogas produced will be used up every day. If you are not at home for a long time or do not use gas, you need to terminate a section of gas pipe on the pressure gauge safety bottle to the outdoor, so that excess biogas can be run away, and absolutely no excess Biogas is left in the room, posing a safety hazard. ^[12]