Biogas plant: recycling organic waste for good. We get biogas with our own hands Gas generator on pig manure

22.04.2020

Today's topic is devoted to obtaining "green" energy from manure. I'll start with a quote: “Large poultry farms and livestock complexes continue to be the most harmful environmental pollutants. For example, only one pig breeding complex with about 100,000 heads produces from 600 to 1,000 tons (under the conditions of using a hydroflush) of manure per day, which is equivalent to the pollution produced by a city with a population of 500,000 people.”

Pictured: The economy is reversed. Biogas plant "Luchki" in the Belgorod region. The cost of 1 kWh of electricity is 7 rubles. To process the agricultural waste of the region, 130 such stations will be required. The more stations, the more losses.

In articles devoted to solving this problem, it is most often proposed to use manure as a raw material for biogas production. We read catchy headlines: “Getting electricity from manure”, “Biogas in a rural courtyard”, “Big dung power plant”, etc. I looked at many sites dedicated to biogas, studied the opinions of many experts, and did not find a single good reason that could convince me of the need to develop this area of alternative energy as applied to eco-farms.

I do not believe in the prospect of manure-derived biogas, and I consider this direction of energy production a dead end, harmful to entrepreneurial initiatives and unprofitable for investors. Realizing that what has been said is just a personal opinion, I am ready for a deeper conversation on this topic. The discussion about the prospects of biogas is important for entrepreneurs, environmentalists, investors and those who face the problem of manure processing (as well as manure and other raw materials).

Of course, the idea of biogas is promoted by manufacturers of expensive biogas equipment, which just won't give up. They don't care about consumer losses, because producing biogas equipment is a very profitable business.

Here are my arguments and facts:

1. Biogas production is unprofitable; the more it was produced, the more debt. This should be covered by a tariff that should be three times higher than the market price of electricity. The payback period for even subsidized biogas projects ranges from 7 years to infinity. There is simply no such long money on the market . Given the reality of the cost of money, even at 15% per annum, such investments never pay off.

2. Since biogas production is unprofitable, it requires direct state support, i.e. administrative resource and budget financing. That is, market mechanisms do not operate in this area. This is the territory of officials, where there is always a corruption component. And this means that the rules of the game for a normal, competitive, independent business are not acceptable.

3. Biogas is explosive (the main component is methane), production must be licensed, and this is also a corruption component . No benefit can justify the risk to the lives of workers.

4. Biogas production requires highly skilled workers. In rural areas, this is an almost impossible condition, and its implementation brings additional costs.

5. We take reference data. 1 ton of manure gives up to 65 cubic meters of biogas. Calorific value of 1 cu. m of biogas is 2 kWh. Before multiplying these figures, let's take into account the biogas consumption for maintaining the technological process of a biogas plant - 50%. In total, 1 ton of pig manure provides 65 kWh of thermal energy.

6. After obtaining biogas, further expensive disposal of what is left is required. And since biogas is obtained with the help of anaerobic bacteria, the broth remaining after fermentation has a strong unpleasant odor. Again expenses.

7. The utilization of this broth by applying it to the soil as a fertilizer has repeatedly led to massive contamination of soil, rivers and food, since this broth is an ideal environment for pathogenic microorganisms.

Conclusion: Biogas production is a life-threatening, economically meaningless and environmentally unjustified direction of manure processing.

But manure needs to be recycled!

1. All high-quality manure (primarily cattle, goat, sheep, rabbit manure) is processed into biohumus with the help of Staratel earthworms. The cost of 1 ton of biohumus, subject to the purchase of manure at 300 rubles per ton, will be about 3 thousand. The market price is from 10 thousand, which ensures high profitability. Biohumus production is waste-free, safe and does not require highly skilled labor.

2. All low-quality manure and manure (for example, pig manure after hydroflushing, etc.) should be processed into solid fuel, i.e. fuel briquettes.

1 ton of manure is approximately 0.5 tons of briquettes, the calorific value of 1 kg of which is about 3.2 kWh, i.e. a ton of manure gives 1600 kWh. thermal energy (and not 65 kWh, as from biogas). That is, the energy is 25 times more, and the cost is the same amount less.

Fuel briquettes from manure are an excellent solution for heating solar bio-vegetarians in winter, on cold and cloudy days. thermal energy both to maintain the microclimate in greenhouses and to generate electricity using Stirling engines, for example.

In addition, we will always have ash - the most valuable source of trace elements and minerals for growing useful plants.

Talking about the energy value of manure and other agricultural waste is also important from the point of view that eco-farmers need simple, economical and safe solutions in the field of "green" energy. For example, the problem of ensuring the energy autonomy and self-sufficiency of the farm, including the solar bio-vegetarian, should be solved.

Since we cannot always use solar or wind energy, it is necessary to have sufficient reserves of backup energy sources. And in this regard, fuel briquettes, including those made from manure, can be a good solution. Accumulating "green" energy in fuel briquettes is much easier than biogas in gas holders.

Every year, energy resources on our planet become less and less. It is because of this that we have to look all the time for new, alternative energy sources. Definitely, after some time our planet will run out of oil and gas deposits, and then the world will have to seriously think about the extraction (collection) and use of biogas as the main source of energy.

What is biogas? Principles of biogas production

As already mentioned, biogas is an alternative source of energy. It is released during the fermentation of various household waste, as well as animal waste (manure).

This method has been used since ancient times in China, but later, centuries later, it was unclaimed and, as a result, was forgotten.

Do-it-yourself biogas production at home

Step 1: Selecting a barrel

First you need to choose a suitable barrel in which we will store the "energy source", that is, as you understand, food waste and manure.

Step 2: Making Holes

We make holes at the inlet and outlet in the barrel. It can be done with a drill, but in this case, the hole is made with a heated metal pipe.

Step 3: Pipe Installation

We install pipes at the inlet and outlet into the holes we made earlier. Pipes are inserted and glued.

Step 4: Creating and Installing the "Gas Tank" Holder

A bucket of 20 liters of paint was taken, this tank will contain the gas we produce. The tank is fixed with a valve used by plumbers.

Step 5: Add cow dung

Mix cow dung (5 kg per 50 liters) and add water. We put it in the tank.

Step 6: Almost done

You will not receive gas for the first 10-15 days, since this time is necessary for all the necessary processes to go through.

Step 7: Get Rid of Carbon Dioxide

In order for this gas to burn, it is necessary to get rid of carbon dioxide. This can be achieved by using a conventional filter, of which there are many in different hardware stores.

Step 8: Done!

You yourself will notice how the "fuel tank" will rise as the chemical reactions occur. Then it is already necessary to open the valve and get biogas.

Biogas can be used for various purposes. It is not recommended to use biogas for cooking, as this can negatively affect the taste (if it does not get rid of flavors).

Video Lesson: Biogas production at home

According to experts of the agro-industrial complex, pet food is digested and assimilated only by 35-40%. The rest of this expensive plant mass passes into manure.

There are several ways to process manure:

manure composting;
microbiological method;
processing using fly larvae and worms.
separation of liquid and solid manure.

When composting, use solid manure (when livestock is littered), liquid manure or the solid fraction of separated liquid manure (when livestock is not littered). When composting, various additives such as peat or chopped straw are added to the manure, all this is mixed with bulldozers on special sites and stacked in heaps. In the process of composting, humus is formed, and an increase in the temperature of the pile leads to the destruction of helminth eggs and weed seeds in the manure. The composts can then be used as plant fertilizer.

Manure composting is one of the old and economical methods of processing this raw material.

The microbiological method of manure processing involves the use of special microbiological cultures that can be added to manure. These organisms convert the beneficial substances contained in manure into a form that is easily absorbed by plants. Microbiological methods of manure processing can be divided into two types:

natural;
artificial.

With natural methods, the transformation of manure components by microorganisms occurs in natural conditions - in the air. For example, in piles or settling tanks. Artificial methods involve the processing of manure in special containers - aeration tanks or metatanks. In the first case (aerobic process, in which the activity of aerobic bacteria is activated), manure is enriched with oxygen, and in the second case (anaerobic process), biogas, which contains methane, is produced by methane-producing bacteria during the fermentation of liquid manure.

Known installations that allow using the larvae of flies to obtain protein feed and humus. Earthworms are also used to obtain similar results. At the same time, the worms produce humus, which increases the nutritional value of humus for plants.

Most modern agro-complexes use the no-litter method of manure removal.

At the same time, with the help of special units, the slurry is separated into liquid and solid fractions, which are processed separately.

Manure processing equipment

Depending on the manure processing technology used, various types of equipment can be used.

Windrow tedding equipment

In the process of composting, for uniform decay, it is necessary to turn over the layers of manure. There are many such units on the market. For example, AVOBO manufactures a range of compost turners for this purpose. They are designed for farms of various sizes and have a capacity of 700 (AVONO 16.30) to 1200 cubic meters per hour (BACKHUS 16.36). A large number of different compost turners are offered by German manufacturers. Their cost lies in the range from 1500 to 5500 euros.

Separators for manure processing

The technology of manure processing in a liquid state involves its initial separation into liquid and solid fractions. Separators are used for this operation.

With the help of a grating (sieve), which is part of the separator, liquid manure is separated into liquid and solid components. Liquid is used for fertilizer, with more complex cleaning, it can be used to irrigate fields. The solid fraction is used to create composts.

The design of the separator includes the following main elements:

electric motor;
cast iron body;
steel screw;
steel working cylinder;
sieve with different mesh sizes;
frame for mounting the device.

An example of such a unit is the press-screw separator of the German company BauerCompact. The motor power of this separator is 3 kW. Price - 13200 euros. The kit also includes a control panel worth 600 euros and an extension and drain line worth 300 euros. Depending on the size of the sieve cells, the capacity of the separator can be from 2 to 11 cubic meters of raw material per hour.

A more powerful S855 separator from the same company with an electric motor power of 7.5 kW and a capacity of 9 to 18 cubic meters per hour costs 37,240 euros.

The separator model of the domestic company "Dalprogress" S-210 has a power of 4 kW and a capacity of 5 cubic meters per hour.

Processing manure into fuel

Plants that convert manure into biogas are widespread in Europe. This is due to the relatively high European prices for gas and electricity, and also with the fact that in the West, farmers who have plants for processing manure into gas and electricity receive preferential loans and compensation for the purchase of such plants. In addition, they have the right to sell the electricity generated at their installations to electric networks at preferential prices. In Russian conditions, these installations are not very common due to the high cost.

The principle of operation of the plant for processing manure into biogas, electricity, heat and fertilizer is as follows:

Each of these installations has a bioreactor. The bioreactor is a container into which manure is loaded in a liquid state. Under the influence of temperature and bacteria, it ferments and forms biogas. This gas can be used in different ways. It can be separated and sold, or it can be used in one production line to produce heat and electricity.

An example of a domestic development is the Prometheus-20 biogas plant.

It converts manure into electrical energy. As a bioreactor, a plastic container of 8 cubic meters is used, in which the biomass is fermented. It produces biogas. The design of the plant provides for the separation of carbon dioxide from the composition of biogas, which increases the content of methane in biogas from 50 to 90%. The plant consists of a gas generator and a boiler that burns biogas and solid residue. At the same time, a liquid residue is separated, which can be used as fertilizer. The plant also generates up to 20 kWh of electricity and up to 3 Gcal/day of thermal energy.

The cost of installation with installation is 1 million 800 thousand rubles, and it can pay off within a year and a half.

Another example of such a system is the Bug complex. It also uses a bioreactor and a gas holder in which biogas accumulates. An aqueous solution of manure is poured into the bioreactor, which releases gas. Then 10–20% of the solution is drained daily and a new part of the mixture is poured.

The drained part is used as fertilizer. Biogas is a mixture of methane and carbon dioxide. Water heaters, household appliances and gas generators can run on this gas. Depending on the model, the complex can produce from 1 to 12 cubic meters of gas per day. The price of the Bug complexes, taking into account the seasonal discount, ranges from 180,000 to 770,000 rubles.

Manure is a valuable product that can be used not only as a fertilizer for fields, but also for the production of biogas, heat and electricity. In addition, manure processing is much simpler and more affordable than, for example,.

For manure processing, both relatively simple equipment such as pile agitators or separators are used, as well as complex equipment, which forms a whole plant for

Prudent owners have long been using eco-technology in practice, which makes it possible to obtain biogas from manure and use the result as fuel.

Therefore, in our material we will talk about the technology for producing biogas, we will also talk about how to build a bioenergy plant.

Determination of the required volume

The volume of the reactor is determined based on the daily amount of manure produced on the farm. It is also necessary to take into account the type of raw materials, temperature and fermentation time. In order for the installation to work fully, the container is filled to 85-90% of the volume, at least 10% must remain free for gas to escape.

The process of decomposition of organic matter in a mesophilic plant at an average temperature of 35 degrees lasts from 12 days, after which the fermented residues are removed and the reactor is filled with a new portion of the substrate. Since the waste is diluted with water up to 90% before being sent to the reactor, the amount of liquid must also be taken into account when determining the daily load.

Based on the given indicators, the volume of the reactor will be equal to the daily amount of the prepared substrate (manure with water) multiplied by 12 (time required for biomass decomposition) and increased by 10% (free volume of the container).

Construction of an underground facility

Now let's talk about the simplest installation, which allows you to get at the lowest cost. Consider building an underground system. To make it, you need to dig a hole, its base and walls are poured with reinforced expanded clay concrete.

From opposite sides of the chamber, inlet and outlet openings are displayed, where inclined pipes are mounted for supplying the substrate and pumping out the waste mass.

The outlet pipe with a diameter of about 7 cm should be located almost at the very bottom of the bunker, its other end is mounted in a rectangular compensating container into which waste will be pumped out. The pipeline for supplying the substrate is located approximately 50 cm from the bottom and has a diameter of 25-35 cm. The upper part of the pipe enters the raw material receiving compartment.

The reactor must be completely sealed. To exclude the possibility of air ingress, the container must be covered with a layer of bituminous waterproofing.

The upper part of the bunker is a gas holder having a dome or cone shape. It is made of metal sheets or roofing iron. It is also possible to complete the structure with brickwork, which is then upholstered with steel mesh and plastered. On top of the gas tank, you need to make a sealed hatch, remove the gas pipe passing through the water seal and install a valve to relieve gas pressure.

To mix the substrate, the unit can be equipped with a drainage system operating on the bubbling principle. To do this, vertically fasten plastic pipes inside the structure so that their upper edge is above the substrate layer. Poke a lot of holes in them. Gas under pressure will go down, and rising up, the gas bubbles will mix the biomass in the tank.

If you do not want to build a concrete bunker, you can buy a ready-made PVC container. To preserve heat, it must be overlaid around with a layer of thermal insulation - polystyrene foam. The bottom of the pit is filled with reinforced concrete with a layer of 10 cm. Polyvinyl chloride tanks can be used if the volume of the reactor does not exceed 3 m3.

Conclusions and useful video on the topic

How to make the simplest installation from an ordinary barrel, you will learn if you watch the video:

The simplest reactor can be made in a few days with your own hands, using available tools. If the farm is large, then it is best to buy a ready-made installation or contact specialists.

Ecology of consumption. Homestead: Farms annually face the problem of manure disposal. Considerable funds are wasted, which are required for organizing its removal and burial. But there is a way that allows you not only to save your money, but also to make this natural product serve you for the benefit.

Farms annually face the problem of manure disposal. Considerable funds are wasted, which are required for organizing its removal and burial. But there is a way that allows you not only to save your money, but also to make this natural product serve you for the benefit. Prudent owners have long been using eco-technology in practice, which makes it possible to obtain biogas from manure and use the result as fuel.

On the benefits of using biotechnology

The technology for obtaining biogas from various natural sources is not new. Research in this area began at the end of the 18th century and successfully developed in the 19th century. In the Soviet Union, the first bioenergy plant was created in the forties of the last century.

The technology of processing manure into biogas makes it possible to reduce the amount of harmful methane emissions into the atmosphere and obtain an additional source of thermal energy

Biotechnologies have long been used in many countries, but today they are of particular importance. Due to the deteriorating environmental situation on the planet and the high cost of energy, many are turning their eyes towards alternative sources of energy and heat.

Of course, manure is a very valuable fertilizer, and if there are two cows on the farm, then there are no problems with its use. Another thing is when it comes to farms with large and medium livestock, where tons of fetid and rotting biological material are formed per year.

In order for manure to turn into high-quality fertilizer, areas with a certain temperature regime are needed, and these are extra costs. Therefore, many farmers store it where necessary, and then take it to the fields.

If storage conditions are not observed, up to 40% of nitrogen and the main part of phosphorus evaporate from manure, which significantly worsens its quality indicators. In addition, methane gas is released into the atmosphere, which has a negative impact on the ecological situation of the planet.

Depending on the volume of raw materials generated per day, the dimensions of the installation and the degree of its automation should be selected.

Modern biotechnologies make it possible not only to neutralize the harmful effects of methane on the environment, but also to make it serve for the benefit of man, while deriving considerable economic benefits. As a result of manure processing, biogas is formed, from which thousands of kW of energy can then be obtained, and production waste is a very valuable anaerobic fertilizer.

What is biogas

Biogas is a colorless and odorless volatile substance that contains up to 70% methane. In terms of its quality indicators, it approaches the traditional type of fuel - natural gas. It has a good calorific value, 1m3 of biogas emits as much heat as is obtained from the combustion of one and a half kilograms of coal.

We owe the formation of biogas to anaerobic bacteria that are actively working on the decomposition of organic raw materials, which are used as manure of farm animals, bird droppings, waste of any plants.

In self-produced biogas, bird droppings and waste products of small and large livestock can be used. The raw material can be used in pure form and in the form of a mixture with the inclusion of grass, foliage, old paper

To activate the process, it is necessary to create favorable conditions for the vital activity of bacteria. They should be similar to those in which microorganisms develop in a natural reservoir - in the stomach of animals, where it is warm and there is no oxygen. Actually, these are the two main conditions that contribute to the miraculous transformation of rotting manure mass into environmentally friendly fuel and valuable fertilizers.

The mechanism of gas formation from organic raw materials

To obtain biogas, you need a sealed reactor without air access, where the process of manure fermentation and its decomposition into components will take place:

Methane (up to 70%).
Carbon dioxide (about 30%).
Other gaseous substances (1-2%).

The resulting gases rise to the top of the tank, from where they are then pumped out, and the residual product settles down - a high-quality organic fertilizer, which, as a result of processing, has retained all the valuable substances in the manure - nitrogen and phosphorus, and has lost a significant part of pathogenic microorganisms.

The biogas reactor must have a completely sealed design, in which there is no oxygen, otherwise the process of manure decomposition will be extremely slow

The second important condition for the effective decomposition of manure and the formation of biogas is compliance with the temperature regime. The bacteria involved in the process are activated at a temperature of +30 degrees. Moreover, manure contains two types of bacteria:

Mesophilic. Their vital activity occurs at a temperature of +30 - +40 degrees;
Thermophilic. For their reproduction, it is necessary to observe the temperature regime of +50 (+60) degrees.

The processing time of raw materials in plants of the first type depends on the composition of the mixture and ranges from 12 to 30 days. At the same time, 1 liter of useful area of the reactor gives 2 liters of biofuel. When using plants of the second type, the time for the production of the final product is reduced to three days, and the amount of biogas increases to 4.5 liters.

The efficiency of thermophilic plants is visible to the naked eye, however, the cost of their maintenance is very high, so before choosing one or another method of obtaining biogas, you need to carefully calculate everything (click to enlarge)

Despite the fact that the efficiency of thermophilic installations is ten times higher, they are used much less often, since maintaining high temperatures in the reactor is associated with high costs. Mesophilic plants are cheaper to maintain and maintain, which is why most farms use them to produce biogas.

Biogas according to the criteria of energy potential is slightly inferior to the usual gas fuel. However, it contains sulfuric acid fumes, the presence of which should be taken into account when choosing materials for the construction of the installation.

Calculations of the efficiency of biogas application

Simple calculations will help to evaluate all the advantages of using alternative biofuels. One cow weighing 500 kg produces about 35-40 kg of manure per day. This amount is enough to produce about 1.5 m3 of biogas, from which, in turn, 3 kWh of electricity can be generated.

Using the data from the table, it is easy to calculate how many m3 of biogas can be obtained at the output in accordance with the number of livestock available on the farm

To obtain biofuels, one can use both one type of organic raw material and mixtures of several components with a moisture content of 85-90%. It is important that they do not contain foreign chemical impurities that adversely affect the processing process.

The simplest mixture recipe was invented back in 2000 by a Russian man from the Lipetsk region, who built the simplest biogas plant with his own hands. He mixed 1500 kg of cow dung with 3500 kg of waste from various plants, added water (about 65% of the weight of all ingredients) and heated the mixture to 35 degrees.

In two weeks, the free fuel is ready. This small installation produced 40 m3 of gas per day, which was enough to heat the house and outbuildings for six months.

Options for manufacturing plants for biofuel production

After carrying out the calculations, it is necessary to decide how to make an installation in order to obtain biogas in accordance with the needs of your farm. If the livestock is small, then the simplest installation is suitable, which is easy to make from improvised means with your own hands.

For large farms that have a constant source of a large amount of raw materials, it is advisable to build an industrial automated biogas system. In this case, it is unlikely that it will be possible to do without the involvement of specialists who will develop the project and mount the installation at a professional level.

The diagram clearly shows how the industrial automated complex for biogas production works. Construction of such a scale can be organized immediately by several farms located nearby

Today, there are dozens of companies that can offer a variety of options: from ready-made solutions to the development of an individual project. To reduce the cost of construction, you can cooperate with neighboring farms (if there are any nearby) and build one plant for all biogas production.

It should be noted that for the construction of even a small installation, it is necessary to draw up the relevant documents, make a technological scheme, a plan for the placement of equipment and ventilation (if the equipment is installed indoors), go through the procedures for coordination with the SES, fire and gas inspection.

Design features of the biogas system

A complete biogas plant is a complex system consisting of:

Bioreactor, where the process of manure decomposition takes place;
Automated organic waste supply system;
Devices for mixing biomass;
Equipment for maintaining optimal temperature conditions;
Gas tank - gas storage tanks;
The receiver of the fulfilled solid waste.

All of the above elements are installed in industrial installations operating in automatic mode. Household reactors, as a rule, have a more simplified design.

The diagram shows the main components of an automated biogas system. The volume of the reactor depends on the daily intake of organic raw materials. For the full functioning of the installation, the reactor must be filled to two-thirds of the volume

The principle of operation and arrangement of the plant for the production of biogas

The main element of the system is the bioreactor. There are several options for its execution, the main thing is to ensure the tightness of the structure and exclude the ingress of oxygen. It can be made in the form of a metal container of various shapes (usually cylindrical) located on the surface. Often, 50 cubic meters of empty fuel tanks are used for these purposes.

You can purchase ready-made containers of a collapsible design. Their advantage is the possibility of quick disassembly, and, if necessary, transportation to another place. It is advisable to use industrial surface installations in large farms, where there is a constant influx of a large amount of organic raw materials.

For small farmsteads, the option of underground placement of the tank is more suitable. An underground bunker is built of brick or concrete. You can bury ready-made containers in the ground, for example, barrels made of metal, stainless steel or PVC. It is also possible their surface placement on the street or in a specially designated room with good ventilation.

For the manufacture of a biogas plant, you can purchase ready-made PVC containers and install them in a room equipped with a ventilation system

Regardless of where and how the reactor is located, it is equipped with a hopper for loading manure. Before loading the raw material, it must undergo preliminary preparation: it is crushed into fractions of no more than 0.7 mm and diluted with water. Ideally, the moisture content of the substrate should be around 90%.

Industrial-type automated plants are equipped with a raw material supply system, including a receiver in which the mixture is brought to the required moisture, a pipeline for water supply and a pumping unit for transferring the mass to the bioreactor.

In home substrate preparation plants, separate containers are used, where the waste is crushed and mixed with water. Then the mass is loaded into the receiving compartment. In reactors located underground, the hopper for receiving the substrate is brought outside, the prepared mixture flows by gravity through the pipeline into the fermentation chamber.

If the reactor is located on the ground or indoors, the inlet pipe with the receiving device can be located in the lower side part of the vessel. It is also possible to bring the pipe to the upper part, and put a socket on its neck. In this case, the biomass will have to be supplied with a pump.

In the bioreactor, it is also necessary to provide an outlet, which is made practically at the bottom of the container on the opposite side from the input hopper. When placed underground, the outlet pipe is installed obliquely upwards and leads to a waste receptacle, shaped like a rectangular box. Its upper edge must be below the level of the inlet.

The inlet and outlet pipes are located obliquely upwards on different sides of the tank, while the compensating tank into which the waste enters must be lower than the receiving hopper

The process proceeds as follows: the input hopper receives a new batch of the substrate, which flows into the reactor, at the same time the same amount of waste sludge rises through the pipe to the waste receiver, from where it is subsequently scooped out and used as a high-quality bio-fertilizer.

Biogas is stored in a gas tank. Most often, it is located directly on the roof of the reactor and has the shape of a dome or cone. It is made of roofing iron, and then, to prevent corrosive processes, it is painted with several layers of oil paint. In industrial plants designed to receive large amounts of gas, the gas tank is often made in the form of a separate tank connected to the reactor by a pipeline.

The gas resulting from fermentation is not suitable for use, because it contains a large amount of water vapor, and in this form it will not burn. To clean it from water fractions, the gas is passed through a water seal. To do this, a pipe is removed from the gas tank, through which biogas enters a container with water, and from there it is supplied to consumers through a plastic or metal pipe.

Diagram of an underground installation. The inlet and outlet should be on opposite sides of the container. Above the reactor there is a water seal through which the resulting gas is passed for drying.

In some cases, special gas holder bags made of polyvinyl chloride are used to store gas. The bags are placed next to the plant and gradually filled with gas. As it is filled, the elastic material inflates and the volume of the bags increases, allowing, if necessary, to temporarily store a larger amount of the final product.

Conditions for the efficient operation of a bioreactor

For efficient operation of the plant and intensive release of biogas, uniform fermentation of the organic substrate is necessary. The mixture must be in constant motion. Otherwise, a crust forms on it, the decomposition process slows down, as a result, less gas is obtained than originally calculated.

To ensure active mixing of the biomass, electrically driven submersible or inclined agitators are installed in the top or side of a typical reactor. In home-made installations, mixing is carried out mechanically using a device resembling a household mixer. It can be operated manually or supplied with an electric drive.

With a vertical arrangement of the reactor, the stirrer handle is displayed in the upper part of the installation. If the container is installed horizontally, the auger is also located in a horizontal plane, and the handle is located on the side of the bioreactor

One of the most important conditions for obtaining biogas is to maintain the required temperature in the reactor. Heating can be done in several ways. In stationary installations, automated heating systems are used, which turn on when the temperature drops below a predetermined level, and turn off when the required temperature is reached.

For heating, you can use gas boilers, direct heating with electric heaters, or build a heating element into the base of the tank. To reduce heat loss, it is recommended to build a small frame around the reactor with a layer of glass wool or to cover the installation with thermal insulation. Expanded polystyrene has good thermal insulation properties.

To equip a biomass heating system, it is possible to lay a pipeline from house heating, which is powered by a reactor

How to determine the correct volume of the reactor

Construction of an underground biogas plant

Now let's talk about the simplest installation that allows you to get biogas at home at the lowest cost. Consider the construction of an underground installation. To make it, you need to dig a hole, its base and walls are poured with reinforced expanded clay concrete. From opposite sides of the chamber, inlet and outlet openings are displayed, where inclined pipes are mounted for supplying the substrate and pumping out the waste sludge.

The reactor must be completely sealed. To exclude the possibility of air ingress, the container must be covered with a layer of bituminous waterproofing.

The upper part of the bunker - the gas holder has a dome or cone shape. It is made of metal sheets or roofing iron. It is also possible to complete the structure with brickwork, which is then upholstered with steel mesh and plastered. On top of the gas tank, you need to make a sealed hatch, remove the gas pipe passing through the water seal and install a valve to relieve gas pressure.

Video about obtaining biogas from manure

How the construction of an underground reactor is going on, you can see in the video:

An installation for biogas production from manure will significantly save on payment for heat and electricity, and use organic material, which is available in abundance in every farm, for a good cause. Before starting construction, everything must be carefully calculated and prepared.

The simplest reactor can be made in a few days with your own hands, using available tools. If the farm is large, then it is best to buy a ready-made installation or contact specialists. published