What is the best material to use for building a biogas digester?

It is recommended that you choose a new type of biogas tank now, the advantage is simple, easy to build its nature is the same as the shape of the septic tank we use now, there is no old-fashioned complexity, its effect is much better than the original, you can save materials, its materials are, red bricks, cement, sand, stones, a small amount of steel can be.

It is recommended to use a good amount of brick-concrete structure.

The design drawing of the biogas digester is the design drawing of the biogas digester, and the principle of fermentation is that organic matter is metabolized by various microorganisms under certain moisture, temperature and anaerobic conditions, and finally produces biogas.

Design drawing of the Chinese name biogas digester.

How it works. When biogas is generated in the pond.

Principles of fermentation. The process of microbial metabolism.

There are three phases of the stage.

How the digester works.

1. The working principle of the biogas digester: when the biogas is generated in the pool, the biogas in the gas storage room continues to increase, and the pressure continues to increase, forcing the liquid level in the main tank to drop and squeezing out a part of the material liquid into the water pressure room. When people turn on the stove, the pressure in the digester gradually drops, and the liquid flows back to the main pond between the water pressure.

In this way, the gas is continuously produced and used, so that the pressure balance between the fermentation room and the discharge room is always maintained.

Biogas digester blueprint.

2. Principle of biogas fermentation:

The process of microbial metabolism is called fermentation, which refers to the process of organic substances under certain moisture, temperature and anaerobic conditions, through the catabolism of various microorganisms, and finally produces biogas. There are three stages to this process:

1) Liquefaction stage: provide nutrients for methanogens and create suitable anaerobic conditions for methanogens to eliminate some poisons.

2) Acid-producing stage.

3) Methanogenic stage: methanogenic flora, using the small molecule compounds decomposed and transformed in the above two steps to generate methane.

P.S. The fermentation room and gas storage room are called the main pool.

The function of the water pressure room is to store the material and liquid extruded from the main pool; Second, it plays the role of pressing out the biogas when using gas.

The cost of raw materials is too high.

Nowadays, more and more young people in rural areas are choosing to go out to work, and those left behind in the countryside are basically the elderly and children, and then some women, and every household no longer raises various animals as in the past, so that the manure of farmers will be reduced a lot, which will lead to a shortage of biogas raw materials. If you want to make the biogas reactor operational, you have to buy materials outside, which is expensive.

2.There is a time limit for use.

Although it is cheap and convenient to use in a hurry, it is limited by the time it can be used. For example, in the rural areas of the north, most of the time biogas is used in late spring, summer and early autumn, and although it can be used at other times, the gas volume is very small, and it is very troublesome to make a fire for cooking. Biogas can only be used normally for more than half a year, which is not as convenient as electricity.

3.More and more new energy sources are emerging.

Now that the rural economy is developing rapidly, and the living standards of farmers have also improved, most families will no longer use the original earthen stoves and coal stoves, but use more simple and convenient gas, induction cookers, solar energy, etc. These new energy sources are easier to use than biogas and are less time-consuming and labor-intensive.

The state has invested a lot of money to build a biogas digester, which is indeed a good thing for the benefit of the country and the people, but these problems in the process of use are also real, and it is precisely because of this that most of the biogas digesters in rural areas have been abandoned, and there are very few farmers who really use them.

A reaction vessel, a biogas appliance will do.

Preparation: The common cooking of the reaction vessel is to dig a circular pit on the ground with a depth of about 2m, leave a filler opening, a discharge port, and use cement to reinforce and prevent water leakage. Then use cement to make a bucket-shaped cover, the size of which is smaller than the pit, and the top of the air pipe interface.

Installation: Introduce an appropriate amount of wastewater into the pit, put the cement cover upside down in the pit, and connect the gas pipe to the biogas burner.

Determine the height of the plus or minus zero of the bai, and DU is determined according to the design drawing; When a new pool starts, a warm DAO is applied

Water start and other versions.

The height of positive and negative zero should be determined. The depth of the pit is determined according to the design drawing, that is, the top of the digester is kept on a level plane with the discharge port, and is 10 cm above the floor of the pig house. In order to facilitate the placement of the pool mold or the use of brick mold to pour the pool body and reduce the loss of materials, the pool pit should be round and vertical up and down.

For areas with good soil quality, the pit wall can be dug straight, and the soil can be excavated from the middle to the surrounding area.

The new pond is preferably started with pure cow and horse manure. When a new pool starts, warm water is applied to start. The water temperature is 30 -50, and it is forbidden to use cold water to start and prolong the starting time.

After feeding, seal the movable cover as required, and pay special attention to sealing the skylight to prevent air leakage. The gas produced at the initial stage of start-up is exhaust gas, which cannot be burned, and should be discharged for 7 days for more than 30 minutes a day.

(1) If simple manure is used as raw material for biogas fermentation, the start of the biogas digester is relatively simple, as long as there is a sufficient amount of inoculum, and the amount of inoculum generally accounts for 15% and 30% of the fermentation liquid. The liquid can be directly taken from the discharge room of the fermentation tank that is running. The sludge from the bottom of the pond, the sediment at the bottom of the manure pit, and the sludge from the city sewage can also be used as inoculum for enrichment and culture, and gradually expand until a large number of inoculated microorganisms are produced.

The total solid content of the fermentation raw materials is about 6%, which is generally simply calculated as putting in 1 part of manure and 3 parts of water, and the total amount of feeding reaches 85% of the volume of the biogas digester, and the movable cover of the biogas digester can be sealed, and when the pressure difference of the water column of the biogas pressure gauge reaches more than 40 cm, all the gas will be discharged. At this time, the biogas cannot be ignited because the air in the gas chamber of the biogas digester is not discharged. When the biogas pressure rises again, with the increase of methane content in the gas, the biogas can be ignited and used, which can be used in 2 to 4 days under normal circumstances.

2) When starting with straw as the main fermentation raw material, first spread the air-dried short or crushed crop straw on the open space next to the biogas digester, with a thickness of about 30 cm, and splash the mixed manure raw materials, inoculum and an appropriate amount of water (the water consumption should be wetted and not flowing, and generally not more than 1 3 of the total water added, and within this dosage range, it should be less in winter). When mixing, it is required to mix well while splashing, and the operation should be fast to avoid the loss of fecal liquid and water. There is no condition to mix into the pool where you can use the method of layered feeding, layered inoculation, first add a layer of straw and then add a layer of manure and inoculum, each layer should not be too thick and should be compacted layer by layer.

After the pile, it is covered with plastic film and piled up, generally 2 to 3 days in summer and 5 to 8 days in winter. The volume of the straw after the pile is reduced to facilitate fermentation in the pond, and the fermentation bacteria multiply in large numbers during the pile process, and the temperature rise can reach up to 60. Stacking can also be carried out in the biogas digester, after the temperature rises to 40 60, you can add water to adjust the pH, if the pH is lower than 6, you can add an appropriate amount of plant ash, lime water to adjust the pH to 7, you can cover the movable cover to seal the pool, and the gas can be deflated and ignited on the biogas stove after 2 or 3 days of sealing the pool.

The construction method of household biogas digester is six steps: site selection, materials, modeling, molding, pouring and capping.

Site selection, it is best to choose a dry place without underground flooding. Consideration should be given to the use of latrine outlets and livestock outlets as feeds for biogas digesters. material, using concrete poured around the digester. Use a well-made wooden formwork. Also use a vibrator to stir firmly.

These basic materials and tools need to be prepared. For modeling, first draw a circle with a radius of meters in the selected position. Take out the soil in the middle, and keep the soil out of this circle for safety.

Calculate, the depth of the pool is meters, the height of the FRP cover is meters, and the floating soil layer is meters. So dig rice deep. Plastic film can be placed on the soil wall as needed.

In the middle of the dug pool, a 3-meter straight pole is erected, one end is inserted into the center, and the other end is fixed with 3 strings. Then the wooden formwork is installed with the rod as the center and the radius in meters. At the same time, put the inlet and outlet pipes.

After pouring, check the stability of the wooden formwork after installation. Next, concrete is used to pour the walls of the pool. Quickly drop the concrete between the formwork and the earth wall.

Be careful not to have clods of soil fall into the soil wall.

Covered, generally the pool wall can be poured 2 days after the wood mold can be removed. Clean up. At this time, the meter diameter FRP cover can be placed on the top surface of the pool wall, and the concrete can be poured around.

Be careful not to deflect the lid. Place 40 cm thick concrete around the lid and pour the lid and the pool wall together. Finally, the bottom of the pool is poured.

Composition of biogas:

Biogas contains a variety of gas components, the main component being methane (CH4). The process by which biogas bacteria decompose organic matter to produce biogas is called biogas fermentation. According to the role of various types of bacteria in the biogas fermentation process, biogas bacteria can be divided into two categories.

The first type of bacteria is called decomposers, which are used to break down complex organic matter into simple organic matter and carbon dioxide (CO2).

Among them, there are those who specialize in breaking down cellulose, called fibrolytic bacteria. There are those that specialize in decomposing proteins, called proteolytic bacteria. There are those that specialize in decomposing fat, called lipolytic bacteria.

The second type of bacteria is called methane-containing bacteria, commonly called methanognes, which oxidizes or reduces simple organic matter and carbon dioxide to methane.

Therefore, the process of turning organic matter into biogas is like the two processes of producing a product in a factory: first, the bacteria are broken down and the complex organic orthodox such as manure, straw, and weeds are processed into semi-chaotic finished products – compounds with simple structures. Then there is the processing of simple compounds into products under the action of methane bacteria – that is, methane is generated.

Wake up and <> cautiously

What materials are needed for site selection, marking, pond digging, material preparation (cement, sand, etc.), molding, concrete pouring to build a biogas digester?

The materials used to build a biogas digester are mainly cement, sand, gravel, and bricks, and some concrete prefabricated components or other molding materials are also needed to make inlet and outlet pipes, pool covers, gas transmission and distribution pipe fittings, lamps, stoves, etc.

What are the steps to build a digester?

1) Check the terrain and determine the location of the biogas digester;

2) Draw up the construction plan and draw the construction drawings;

3) Prepare materials for pond construction;

4) Pay-off; 5) Excavation of earthwork;

6) Molds (outer molds and inner molds);

7) Concrete pouring, or brick masonry, or prefabricated concrete slab assembly;

8) Maintenance; 9) Mold removal;

10) backfill;

11) sealing layer construction;

12) Installation of gas transmission and distribution pipe fittings, lamps and stoves;

13) Pressure test, acceptance.