Required required materials:

• two containers;
• connecting pipes;
• valves;
• gas filter;
• means of ensuring tightness (glue, resin, sealant, etc.);

Desirable:

• stirrer with electric motor;
• temperature sensor;
• pressure meter;

The following sequence is suitable for the southern regions. For performance in any conditions, it is necessary to add a reactor heating system, which will provide heating of the vessel to 40 degrees Celsius and increase thermal insulation, for example, enclose the structure with a greenhouse. It is desirable to cover the greenhouse with a black film. It is also desirable to add a condensate outlet to the pipeline.

Building a simple biogas plant:

1. Create a storage tank. We select a tank where the resulting biogas will be stored. The tank is fixed with a valve and equipped with a pressure gauge. If gas consumption is constant, then there is no need for a gas tank.
2. Insulate the structure inside the pit.
3. Install pipes. Lay pipes in the pit for loading raw materials and unloading compost humus. An inlet and an outlet are made in the reactor vessel. The reactor is placed in a pit. Pipes are connected to the holes. The pipes are tightly fixed with glue or other suitable means. Pipe diameters less than 30 cm will contribute to clogging. The loading place should be chosen on the sunny side.
4. Install sunroof. The rector, equipped with a hatch, makes repair and maintenance work more convenient. The hatch and the reactor vessel should be glued with rubber. Temperature, pressure and raw material level sensors can also be installed.
5. Choose a container for the bioreactor. The selected container must be durable - since a large amount of energy is released during fermentation; have good thermal insulation; be air and waterproof. Egg-shaped vessels are best suited. If it is problematic to build such a reactor, then a cylindrical vessel with rounded edges would be a good alternative. Square-shaped containers are less efficient because hardened biomass will accumulate in the corners, making fermentation difficult.
6. Prepare a pit.
7. Choose a place for mounting the future installation. It is advisable to choose a place far enough from the house and so that you can dig a hole. Placement inside the pit allows you to significantly save on thermal insulation, using cheap materials like clay for this.
8. Check the tightness of the resulting structure.
9. Start system.
10. Add raw materials. We are waiting for about two weeks until all the necessary processes take place. A necessary condition for gas combustion is to get rid of carbon dioxide. For this, a regular filter from a hardware store is suitable. A homemade filter is made from a 30 cm long piece of gas pipe filled with dry wood and metal shavings.

Composition and types

Biogas is a gas obtained as a result of a three-phase biochemical process over biomass, taking place under sealed conditions.

The process of biomass decomposition is sequential: first it is exposed to hydrolytic bacteria, then acid-forming and finally methane-forming. The material for microorganisms at each stage is the product of the activity of the previous stage.

At the output, the approximate composition of biogas looks like this:

• methane (from 50 to 70%);
• carbon dioxide (from 30 to 40%);
• hydrogen sulfide (~2%);
• hydrogen (~1%);
• ammonia (~1%);

The accuracy of the proportions is affected by the raw materials used and the gas production technology. Methane has the potential for combustion, the higher its percentage, the better.

Ancient cultures dating back more than three thousand years (India, Persia or Assyria) have experience in the use of combustible swamp gas. The scientific justification was formed much later. The chemical formula of methane CH 4 was discovered by the scientist John Dalton, the occurrence of methane in the swamp gas was discovered by Humphry Davy. A major role in the development of the alternative energy industry was played by the Second World War, which requires the warring parties to have a huge need for energy resources.

The possession of huge reserves of oil and natural gas by the USSR led to the lack of demand for other technologies for generating energy, the study of biogas was mainly the subject of interest of academic science. At the moment, the situation has changed so much that, in addition to the industrial production of various types of fuel, any person can create a biogas plant for their own purposes.

- a set of equipment designed to produce biogas from organic raw materials.

According to the type of raw material supply, the following types of biogas plants are distinguished:

• with portion feed;
• with continuous supply;

Biogas plants with a constant supply of raw materials are more efficient.

By type of processing of raw materials:

1. Without automatic mixing raw materials and maintaining the required temperature - complexes with a minimum configuration, suitable for small farms (scheme 1).
2. With automatic mixing, but without maintaining the required temperature - also serves small farms, more efficiently than the previous type.
3. Maintaining the desired temperature, but without automatic mixing.
4. With automatic mixing of raw materials and temperature support.

Principle of operation

The process of converting organic raw materials into biogas is called fermentation. The feedstock is loaded into a special container that provides reliable protection of biomass from oxygen access. An event that occurs without the intervention of oxygen is called anaerobic.

Under the influence of special bacteria in an anaerobic environment, fermentation begins to occur. As fermentation develops, the raw material becomes covered with a crust, which must be regularly destroyed. Destruction is done by thorough mixing.

Stirring the contents is required at least twice a day, without violating the tightness of the process. In addition to removing the crust, stirring allows you to evenly distribute the acidity and temperature within the organic mass. As a result of these manipulations, biogas is produced.

The resulting gas is collected in a gas tank, from there it is delivered to the consumer through pipes. Biofertilizers obtained after the processing of raw materials can be used as a food supplement for animals or added to the soil. This fertilizer is called compost humus.

The biogas plant includes the following elements:

• homogenization tank;
• reactor;
• agitators;
• storage tank (gas-holder);
• heating and water mixing complex;
• gas complex;
• complex of pumps;
• separator;
• control sensors;
• I&C with visualization;
• safety system;

An example of an industrial type biogas plant is shown in Scheme 2.

Raw materials used

The decomposition of any animal or plant residues releases flammable gas to varying degrees. Mixtures of various compositions are well suited for raw materials: manure, straw, grass, various waste, etc. The chemical reaction requires a humidity of 70%, so the raw material must be diluted with water.

The presence of cleaning agents, chlorine, washing powders in organic biomass is unacceptable, since they interfere with chemical reactions and can damage the reactor. Also not suitable for the reactor is raw material with sawdust from coniferous trees (containing resins), with a high proportion of lignin and exceeding the moisture threshold of 94%.

Vegetable. Vegetable raw materials are excellent for biogas production. Fresh grass gives the maximum fuel yield - about 250 m 3 of gas with a methane share of 70% is obtained from a ton of raw materials. Corn silage is slightly smaller - 220 m 3 . Tops from beets - 180 m 3.

Almost any plant, hay or algae can be used as biomass. The disadvantage of the application lies in the duration of the production cycle. The biogas production process takes up to two months. The raw material must be finely ground.

Animal. Waste from processing, dairy, slaughterhouses, etc. suitable for biogas plant. Animal fats give the maximum fuel yield - 1500 m 3 of biogas with a methane share of 87%. The main drawback is scarcity. Animal raw materials must also be crushed.

Excrement. The main advantage of manure is its low cost and easy accessibility. The disadvantage is that the quantity and quality of biogas is lower than from other types of raw materials. Horse and cow dung can be recycled immediately. The production run will take approximately two weeks and will yield a 60 m 3 output with 60% methane content.

Chicken manure and pig manure cannot be used directly because they are toxic. To start the fermentation process, they must be mixed with silage. A human waste product can also be used, but sewage will not work, as the feces content is low.

Work schemes

Scheme 1 - biogas plant without automatic mixing of raw materials:

Scheme 2 - biogas plant of industrial type:

Biogas plants for farms, the price depends on the number of components, various parameters characteristic of such devices, varies within 170 thousand rubles.

They work to obtain, as a result of the processing of the final product, environmentally friendly fuel, fertilizers, which are produced in the unit, which includes technical structures, devices, combined in a single technological cycle.

Biogas plants for the home may one day completely replace expensive energy sources for the rural dweller. Economic cataclysms require developers of equipment for agriculture to produce analogues of natural resources in the form of improvised raw materials to reduce the cost of maintaining a private farmstead, farming.

The goals of farmers are different - some get cheap energy for others, it is important to process waste with the help of a small mini installation:

• cattle

As a result of the work, biofertilizers and their own energy source are obtained. In addition, farms have to get rid of various accumulations of household waste; in this they are helped by a convenient, universal facility that gives useful products instead of unnecessary.

Who operates the equipment

Small biogas plants will be useful in modern rural farms. Larger devices are used by serious pastoralists, where it is impossible to exist without units that produce the necessary energy species.

The justification for installation in the backyard of a private house or a large farm is the accumulation of organic matter, since any equipment needs power to work.

The world is fighting for the ecology of the environment, the most acceptable means for this are the construction of biogas facilities, they release pure substances and consume alternative fuels. On this basis, the devices have received demand in the farms of our country and abroad.

Standard equipment

Engineers complete mechanisms of different sizes. Production depends on the required power, which is to be processed by the unit and issued in exchange. The standard view installation consists of the following components:

• storage tank, it receives material for mining
• mixers, mills structurally different from each other, they grind large raw fragments
• gas tank, hermetically sealed, gas accumulates here
• a reactor in the form of a tank where biofuel is formed
• devices that feed raw materials into a container
• installations that transfer the received fuel from one point to another for subsequent conversion
  automatic systems that protect and control the production process

The work of the technological cycle has been worked out to the smallest detail in order to make it easier for a person to maintain the unit during the processing period.

How it works

The performance of the aggregates is based on the principle of the impact of bacterial formations of various nature on organic matter, causing fermentation. These processes take place inside the reactor. From the decomposition of some products, another substance is obtained, it consists of:

• methane
• carbon dioxide
• impurities of ammonia, hydrogen sulfide, nitrogen

The principle of operation consists of the following actions:

• raw materials are fed into the storage tank
• the material is broken up, pumps, conveyors move to the acid tank, in this tank the biomass is subjected to additional heating
• durable, acid-resistant, tightly closed reactor accepts prepared raw materials to create biogas

Devices are installed in the reactor to provide additional heating, within +40 degrees, of mixing substances, create suitable conditions for them, accelerating the processes of decomposition and fermentation, from which the final product is formed. The recycling rate depends on the capacity of the facility and the type of waste.

In the process:

• gas accumulation is carried out in gas tanks, they are mounted as a separate element or connected together with the body
• the reactor capacity collects, after the completion of the decomposition procedure, it transfers for use
• enough pressure is created in the tank of the gas tank to move the gas into the purification system, in this form it will be used by the consumer in various fields of activity
• intended use acquire substances for fertilizers after their separation into components in liquid or solid form, and transfer to the storage part

The decision to start construction should be accompanied by consideration of the conditions under which biogas plants operate with the required efficiency.

Basic options for selection

Poor device functionality is due to poor planning. Errors can be noticed immediately or after a while. A thorough and comprehensive study is made to exclude equipment failure. The procedure begins after determining the availability of raw material and how much is needed for the normal existence of energy resources.

The reactor and its dimensions are affected by:

• amount of processing
• material quality
• raw material
• temperature regime
• fermentation period

In practice, in a particular farm, attention should be paid to the following points:

• daily loading of materials in relation to the reactor size
• the volume of the container in which waste is processed
• calculate the output
• the possibility of balancing between the result and actual consumption

Before installing the equipment, you have to make a choice:

• the best place to install
• models suitable for design features

The main criteria on which the constructive choice is based are the place and the definition of an underground or surface structure. In addition, when arranging the structure at the top, one should decide how to install the reactor in a vertical or horizontal position.

Biofertilizers are stored in buildings on the site or in pits, metal barrels. Costs will reduce the finished parts of the installation, if they are on the farm. The accumulation of materials determines the size and shape of the tanks in which they are mixed, as well as what reactor is needed, devices for heating substances, crushing and mixing them.

The selected reactor design must comply with:

• practicality
• ease of maintenance
• gas- and water-tight to eliminate leaks and keep the gas in full

A prerequisite for effective performance is the presence of high-quality thermal insulation. It is possible to reduce construction costs and heat losses with minimal surface areas.

The structure must be stable, withstand pressure loads:

• raw materials

Installations are equipped in the following most optimal forms:

• egg-shaped
• cylindrical
• conical
• semicircular

It is not recommended to equip square forms of concrete or brick. The raw material exerts pressure on the corners, causing cracks to appear, disrupt the processes occurring inside, solid accumulating fragments. Materials roam better, dried surfaces do not appear in structures with internal partitions.

The best building materials are:

• Steel - in these containers you can achieve absolute tightness, they are easy to manufacture, they withstand loads. The problem is increased susceptibility to corrosion. Surfaces are treated to prevent rust. If the farm has a metal tank, its quality should be checked from all sides. Get rid of imperfections.
• Plastic - tanks made of this material are produced soft and hard. The first option is less suitable, since damage is easily caused, it is difficult to insulate. Hard plastic tanks are stable and will not rust.
• Concrete is used by some developing countries. They have no restrictions in terms of operation, special coatings can eliminate the appearance of cracks.
• Brick is used by India and China. For this, only well-burnt products are used or walls made of concrete blocks or stone are laid.

When installing equipment made of concrete, brick or stone, it is necessary to take care of the internal refractory finish that is resistant to organic matter and hydrogen sulfide.

The location of the structure should be taken with particular seriousness, to provide factors:

• vacant areas
• distance from housing
• warehousing
• location of barns, pigsties, poultry houses
• ground water
• convenient loading and unloading of materials

Reactors host:

• on the surface with foundation
• buried in the ground
• installed inside the farm

Devices operating with the help of a chemical, biological reaction are equipped with hatches through which periodic repairs are carried out. The rubber gasket provides a seal when the lid is closed. Thermal insulation is necessary to carry out work regardless of the season.
The building is insulated with improvised materials with layer-by-layer processing of internal surfaces.

A do-it-yourself biogas plant can be done without much effort. Its use will significantly save on energy resources, which today are becoming more and more expensive each time. If you decide on your own to build equipment that allows you to get biogas from waste, you can consume cheap energy that will be used for heating your home and other needs.

Beneficial use

If during the operation of the plant surpluses of biogas or fertilizers are formed, then there is an opportunity to sell them at a market price, thereby turning what is literally under your feet into profit. If you are a large farmer, then you have the opportunity to purchase a ready-made biogas station. Such installations, produced in the factory, are very expensive, but they have a long lifespan.

A do-it-yourself biogas plant can be made from improvised materials, it will not cost very much, and such equipment will work on the same principle. In this case, you can use the available tools, as well as the details available in the arsenal of the master.

The principle of biogas formation

If you set out to make an installation that will run on biogas, then you need to present the technology for generating biogas. So, in a special container, which is called a bioreactor, the process of processing biological mass is carried out, anaerobic bacteria take part in this.

A do-it-yourself biogas plant for a house on quail manure works on the principle of creating conditions that are characterized by the absence of air and fermentation. All this lasts for some time, the duration of which depends on the amount of raw materials used in the process.

Ultimately, a mixture of gases is formed, which contains 60% methane and 35% carbon dioxide. The remaining gaseous components are contained in the mass in an amount of 5%. Among the latter, hydrogen sulfide can be distinguished in a small amount. The gas formed in this way is continuously withdrawn from the reactor, and after it undergoes a purification process, it enters the intended use.

Service Features

Waste that has undergone processing becomes high-quality fertilizers, which must be removed from the bioreactor from time to time. They can be laid on the fields. A do-it-yourself biogas plant can be done without much effort if you have access to livestock and agricultural businesses. This indicates that the production of biogas will only become economically viable if there is a source of supply of manure and other organic waste from livestock production.

Features of self-construction of a bioreactor

In order to understand how to make a biogas plant on your own, you need to figure out what parts it consists of. You can take as a basis the simplest scheme of equipment that can be built on your own. The design does not provide for heating and mixing, but there is one of the main parts - the reactor, which is also known as a methane tank. This component is required for the implementation of manure processing. In addition, there is a bunker through which raw materials are loaded. It is necessary to provide the structure with an entrance hatch, as well as a water seal. But in order to be able to unload the waste raw materials, a pipe will be needed. A similar element will be required in order to realize the possibility of removing biogas.

This is what a biogas plant looks like. It is not difficult to make such a design with your own hands. In order to receive free biofuel, you should choose a place on the site where you can build a reinforced tank, which will be based on concrete. This vessel will act as a bioreactor. At its base, it is necessary to provide for the presence of a hole through which raw materials that have been worked out will be removed. This hole must be made in such a way that it is possible to close it well. This is due to the fact that the functioning of the system is possible only in sealed conditions.

The dimensions of the concrete compartment can be determined taking into account the amount of organic waste used at a time. It is necessary to find out how much raw material will appear every day in a farm or a private courtyard. But you should not save money, since it will be possible to ensure the full operation of the bioreactor only if the tank is filled to 2/3 of the available volume. If you make a biogas plant with your own hands from a barrel, then it will work according to the following principle: as soon as organic waste enters the well-closed container of the bioreactor, which is located at a depth in the soil, they begin to ferment, which leads to the release of biogas.

Features of the manufacture of containers

A do-it-yourself biogas plant can be made taking into account the daily use of a small amount of waste. In this case, it is permissible to replace the reinforced concrete tank with a steel container, which can even be a barrel. If you decide to resort to just such a solution, then it is necessary to choose a metal vessel, guided by some rules.

First of all, you need to pay attention to the welds, which must be strong enough and tight. When using a small container, you should not count on the fact that it will be possible to obtain a significant amount of biogas. The output will depend on the mass of organic waste that is simultaneously processed in the reactor. Thus, in order to form 100 m 3 of biogas, it is necessary to process a ton of waste.

Reactor heating equipment

A do-it-yourself biogas plant for the home can be made in such a way that during its operation it will be possible to obtain greater efficiency. This is provided by heating. Such manipulations will speed up the process of fermentation of the biological mass. If the equipment is installed in the southern regions, then this need does not arise. The ambient temperature provides a natural activation of fermentation. However, if the plant operates in regions with a cold climate, then during the winter period, heating acts as a necessary condition for the operation of biogas production equipment. It must be remembered that the fermentation process begins at a temperature that exceeds 38 ° C.

Methods for equipping a biogas plant with heating

A do-it-yourself biogas plant for the home can be equipped with heating in several ways. The first involves the need to connect the unit to the heating system as a coil. It must be mounted under the reactor. The second method involves the installation of an electric heating element in the base of the tank. The third method is characterized by the provision of direct heating of the tank by using electric heating systems. gas equipment. The activation of the production of biological gas at home can be supplemented by the function of mixing the mass in the compartment. To do this, design a device that resembles a household mixer. It will be driven by a shaft through a hole in the lid, alternatively it can be placed in the walls of the tank.

Installation equipment output system

A do-it-yourself mini-biogas plant cannot work without a gas exhaust system. To do this, the installation must have a special hole that must be mounted in the upper part of the cover, the latter must close the tank well. To exclude the possibility of mixing gas with air, it is necessary to ensure its removal through the hydraulic seal.

One of the tasks that have to be solved in agriculture is the disposal of manure and plant waste. And this is a rather serious problem that requires constant attention. Recycling takes not only time and effort, but also a decent amount. Today there is at least one way to turn this headache into an income item: processing manure into biogas. The technology is based on the natural process of decomposition of manure and plant residues due to the bacteria contained in them. The whole task is to create special conditions for the most complete decomposition. These conditions are the lack of oxygen access and the optimum temperature (40-50 o C).

Everyone knows how manure is most often disposed of: piled up, then, after fermentation, taken out to the fields. In this case, the resulting gas is released into the atmosphere, and 40% of the nitrogen contained in the original substance and most of the phosphorus also fly there. The resulting fertilizer is far from perfect.

To obtain biogas, it is necessary that the process of manure decomposition takes place without access to oxygen, in a closed volume. In this case, both nitrogen and phosphorus remain in the residual product, and the gas accumulates in the upper part of the tank, from where it can be easily pumped out. Two sources of profit are obtained: gas directly and effective fertilizer. Moreover, the fertilizer is of the highest quality and is 99% safe: most of the pathogens and helminth eggs die, the weed seeds contained in manure lose their germination capacity. There are even lines for packaging this residue.

The second prerequisite for the process of processing manure into biogas is maintaining the optimum temperature. Bacteria contained in the biomass are inactive at low temperatures. They begin to act at an ambient temperature of +30 o C. Moreover, two types of bacteria are contained in manure:

Thermophilic plants with temperatures from +43 o C to +52 o C are the most efficient: manure is processed in them for 3 days, up to 4.5 liters of biogas is obtained from 1 liter of bioreactor useful area (this is the maximum output). But maintaining a temperature of +50 o C requires significant energy costs, which is not profitable in every climate. Therefore, more often biogas plants operate at mesophilic temperatures. In this case, the processing time can be 12-30 days, the yield is approximately 2 liters of biogas per 1 liter of bioreactor volume.

The composition of the gas varies depending on the feedstock and processing conditions, but approximately it is as follows: methane - 50-70%, carbon dioxide - 30-50%, and also contains a small amount of hydrogen sulfide (less than 1%) and a very small amount of ammonia, hydrogen and nitrogen compounds. Depending on the design of the plant, biogas can contain a significant amount of water vapor, which will require dehydration (otherwise it simply will not burn). What the industrial installation looks like is shown in the video.

It can be said a whole gas production plant. But for a private courtyard or a small farm, such volumes are useless. The simplest biogas plant is easy to do with your own hands. But the question is: “Where to send biogas next?” The calorific value of the resulting gas is from 5340 kcal / m3 to 6230 kcal / m3 (6.21 - 7.24 kWh / m3). Therefore, it can be supplied to a gas boiler for heat generation (heating and hot water), or to an electricity generation plant, gas stove, etc. This is how Vladimir Rashin, the designer of a biogas plant, uses manure from his quail farm.

It turns out that having at least some more or less decent amount of livestock and poultry, you yourself can fully meet the needs of your farm in heat, gas and electricity. And if you install gas installations on cars, then fuel for the fleet. Given that the share of energy in the cost of production is 70-80%, you can only save on a bioreactor, and then earn a lot of money. Below is a screenshot of the economic calculation of the profitability of a biogas plant for a small farm (as of September 2014). You can’t call the economy small, but it’s definitely not large either. We apologize for the terminology - this is the author's style.

This is an approximate breakdown of the required costs and possible income. Schemes of self-made biogas plants

Schemes of self-made biogas plants

The simplest scheme of a biogas plant is a sealed container - a bioreactor, into which the prepared slurry is poured. Accordingly, there is a hatch for loading manure and a hatch for unloading processed raw materials.

The simplest scheme of a biogas plant without "bells and whistles"

The container is not completely filled with the substrate: 10-15% of the volume must remain free to collect gas. A gas pipe is built into the tank lid. Since the resulting gas contains a rather large amount of water vapor, it will not burn in this form. Therefore, it is necessary to pass it through a water seal for drainage. In this simple device, most of the water vapor will condense, and the gas will already burn well. Then it is desirable to purify the gas from non-combustible hydrogen sulfide, and only then it can be fed into the gas holder - a container for collecting gas. And from there it is already possible to breed to consumers: feed it to a boiler or a gas stove. How to make filters for a biogas plant with your own hands, see the video.

Large industrial installations are placed on the surface. And this, in principle, is understandable - the volume of land work is too large. But in small farms, the bunker bowl is buried in the ground. This, firstly, allows you to reduce the cost of maintaining the required temperature, and secondly, in a private courtyard, there are already enough devices.

The container can be taken ready-made, or made of brick, concrete, etc. in a dug pit. But in this case, you will have to take care of the air tightness and obstruction: the process is anaerobic - without air access, therefore it is necessary to create a layer impermeable to oxygen. The construction turns out to be multi-layered and the manufacture of such a bunker is a long and costly process. Therefore, it is cheaper and easier to bury the finished container. Previously, these were necessarily metal barrels, often stainless steel. Today, with the advent of PVC containers on the market, you can use them. They are chemically neutral, have low thermal conductivity, long service life, and are several times cheaper than stainless steel.

But the biogas plant described above will have low productivity. To activate the processing process, active mixing of the mass in the hopper is necessary. Otherwise, a crust is formed on the surface or in the thickness of the substrate, which slows down the decomposition process, and less gas is obtained at the outlet. Mixing is carried out in any available way. For example, as shown in the video. In this case, any drive can be made.

There is another way of mixing the layers, but non-mechanical - barbitation: the gas produced under pressure is fed into the lower part of the manure tank. Rising up, gas bubbles will break the crust. Since the same biogas is supplied, there will be no changes in processing conditions. Also, this gas cannot be considered an expense - it will again fall into the gas tank.

As mentioned above, high temperatures are required for good performance. In order not to spend too much money on maintaining this temperature, it is necessary to take care of the insulation. What type of heat insulator to choose, of course, is your business, but today the most optimal one is polystyrene foam. It is not afraid of water, is not affected by fungi and rodents, has a long service life and excellent thermal insulation performance.

The shape of the bioreactor can be different, but the most common is cylindrical. It is not ideal in terms of the complexity of mixing the substrate, but is used more often because people have accumulated a lot of experience in building such containers. And if such a cylinder is divided by a partition, then they can be used as two separate tanks in which the process is shifted in time. At the same time, a heating element can be built into the partition, thus solving the problem of maintaining the temperature in two chambers at once.

In the simplest version, home-made biogas plants are a rectangular pit, the walls of which are made of concrete, and treated with a layer of fiberglass and polyester resin for tightness. This container comes with a lid. It is extremely inconvenient in operation: it is difficult to implement heating, mixing and removal of the fermented mass, it is impossible to achieve complete processing and high efficiency.

The situation is slightly better with trench biogas manure processing plants. They have beveled edges, which makes it easier to load fresh manure. If you make the bottom sloped, then the fermented mass will move by gravity in one direction and it will be easier to select it. In such installations, it is necessary to provide thermal insulation not only for walls, but also for covers. Such a biogas plant with your own hands is easy to implement. But full processing and the maximum amount of gas in it cannot be achieved. Even when heated.

The basic technical issues have been dealt with and you now know several ways to build a manure biogas plant. Remained technological nuances.

What can be recycled and how to achieve good results

In the manure of any animal there are organisms necessary for its processing. More than a thousand different microorganisms have been found to be involved in the digestion process and gas generation. The most important role is played by methane-formers. It is also believed that all these microorganisms are found in optimal proportions in cattle manure. In any case, when processing this type of waste in combination with plant mass, the largest amount of biogas is released. The table shows averaged data for the most common types of agricultural waste. Please note that this amount of gas output can be obtained under ideal conditions.

For good productivity, it is necessary to maintain a certain humidity of the substrate: 85-90%. But water must be used that does not contain foreign chemicals. Solvents, antibiotics, detergents, etc. negatively affect the processes. Also, for the normal course of the process, the slurry should not contain large fragments. The maximum size of the fragments: 1 * 2 cm, smaller ones are better. Therefore, if you plan to add herbal ingredients, then you need to grind them.

It is important for normal processing in the substrate to maintain an optimal pH level: within 6.7-7.6. Usually the medium has normal acidity, and only occasionally acid-forming bacteria develop faster than methane-forming ones. Then the environment becomes acidic, gas production decreases. To achieve the optimal value, ordinary lime or soda is added to the substrate.

Now a little about the time it takes to process manure. In general, the time depends on the created conditions, but the first gas can begin to flow already on the third day after the start of fermentation. The most active gas formation occurs during the decomposition of manure by 30-33%. To be able to navigate in time, let's say that after two weeks the substrate decomposes by 20-25%. That is, optimal processing should last a month. In this case, the fertilizer is of the highest quality.

Calculation of the volume of the bunker for processing

For small farms, the optimal setting is permanent action - this is when fresh manure is supplied in small portions daily and removed in the same portions. In order for the process not to be disturbed, the share of the daily load should not exceed 5% of the processed volume.

Home-made installations for the processing of manure into biogas are not the pinnacle of perfection, but they are quite effective

Based on this, you can easily determine the required tank volume for a homemade biogas plant. You need to multiply the daily volume of manure from your farm (already diluted with a moisture content of 85-90%) by 20 (this is for mesophilic temperatures, for thermophilic temperatures you will have to multiply by 30). Another 15-20% must be added to the figure obtained - free space for collecting biogas under the dome. You know the main parameter. All further costs and parameters of the system depend on which scheme of the biogas plant is chosen for implementation and how you will do everything. It is quite possible to get by with improvised materials, or you can order a turnkey installation. Factory developments will cost from 1.5 million euros, installations from the Kulibins will be cheaper.

Legal registration

The installation will have to be coordinated with the SES, gas inspection and firefighters. You will need:

• Technological scheme of the installation.
• Layout plan for equipment and components with reference to the installation itself, the installation site of the thermal unit, the location of pipelines and power lines, and the connection of the pump. Lightning rod and access roads should be marked on the diagram.
• If the unit is to be located indoors, a ventilation plan will also be required, which will ensure at least eight exchanges of the total air in the room.

As you can see, bureaucracy is indispensable here.

Finally, a little about the performance of the installation. On average, a biogas plant produces a volume of gas per day that is twice the useful volume of the reservoir. That is, 40 m 3 of slurry will give 80 m 3 of gas per day. Approximately 30% will be spent on ensuring the process itself (the main expense item is heating). Those. at the output you will receive 56 m 3 of biogas per day. To cover the needs of a family of three and to heat a medium-sized house, according to statistics, 10 m 3 is required. In the net balance you have 46 m 3 per day. And this is with a small installation.

Results

By investing some money in the construction of a biogas plant (do it yourself or on a turnkey basis), you will not only provide for your own needs and needs for heat and gas, but also be able to sell gas, as well as high-quality fertilizers resulting from processing.

The issue of obtaining methane is of interest to those owners of private farms who breed poultry or pigs, and also keep cattle. As a rule, such farms produce a significant amount of organic animal waste, and it is they who can bring considerable benefits, becoming a source of cheap fuel. The purpose of this material is to tell you how to get biogas at home using these very wastes.

General information about biogas

Derived from various manure and bird droppings, domestic biogas mostly consists of methane. There it is from 50 to 80%, depending on whose waste products were used for production. The same methane that burns in our stoves and boilers, and for which we sometimes pay a lot of money according to the meter readings.

To give an idea of ​​the amount of fuel that can theoretically be obtained by keeping animals at home or in the country, we present a table with data on the yield of biogas and the content of pure methane in it:

As can be seen from the table, for the efficient production of gas from cow dung and silage waste, quite a large amount of raw materials will be needed. It is more profitable to extract fuel from pig manure and turkey droppings.

The rest of the substances (25-45%) that make up home biogas are carbon dioxide (up to 43%) and hydrogen sulfide (1%). Also in the composition of the fuel there is nitrogen, ammonia and oxygen, but in small quantities. By the way, it is thanks to the release of hydrogen sulfide and ammonia that the dunghill emits such a familiar “pleasant” smell. As for the energy content, 1 m3 of methane can theoretically release up to 25 MJ (6.95 kW) of thermal energy during combustion. The specific heat of combustion of biogas depends on the proportion of methane in its composition.

For reference. In practice, it has been verified that for heating an insulated house located in the middle lane, about 45 m3 of biological fuel per 1 m2 of area per heating season is required.

By nature, it is arranged in such a way that biogas from manure is formed spontaneously and regardless of whether we want to receive it or not. The dung heap rots within a year - one and a half, just being in the open air and even at sub-zero temperatures. All this time, it emits biogas, but only in small quantities, since the process is extended in time. The reason is hundreds of species of microorganisms found in animal excrement. That is, nothing is needed to start gassing, it will occur on its own. But to optimize the process and speed it up, special equipment will be required, which will be discussed later.

Biogas technology

The essence of efficient production is the acceleration of the natural process of decomposition of organic raw materials. To do this, the bacteria in it need to create the best conditions for the reproduction and processing of waste. And the first condition is to place the raw material in a closed container - a reactor, otherwise - a biogas generator. The waste is crushed and mixed in the reactor with the calculated amount of pure water until the initial substrate is obtained.

Note. Clean water is necessary so that substances that adversely affect the vital activity of bacteria do not get into the substrate. As a result, the fermentation process can be greatly slowed down.

The industrial plant for the production of biogas is equipped with substrate heating, mixing facilities and control over the acidity of the medium. Agitation is performed to remove the hard crust from the surface, which occurs during fermentation and interferes with the release of biogas. The duration of the technological process is at least 15 days, during which time the degree of decomposition reaches 25%. It is believed that the maximum fuel yield occurs up to 33% of biomass decomposition.

The technology provides for daily renewal of the substrate, thus ensuring intensive production of gas from manure, in industrial installations it amounts to hundreds of cubic meters per day. Part of the spent mass in the amount of about 5% of the total volume is removed from the reactor, and the same amount of fresh biological raw materials is loaded in its place. The waste material is used as organic fertilizer for the fields.

Scheme of a biogas plant

By obtaining biogas at home, it is impossible to create such favorable conditions for microorganisms as in industrial production. And first of all, this statement concerns the organization of heating the generator. As you know, this requires energy, which leads to a significant increase in the cost of fuel. It is quite possible to control compliance with the slightly alkaline environment inherent in the fermentation process. But how to correct it in case of deviations? Again costs.

Owners of private households who want to produce biogas with their own hands are advised to make a reactor of a simple design from available materials, and then upgrade it to the best of their ability. What need to do:

• a hermetically sealed container with a volume of at least 1 m3. Different tanks and barrels of small sizes are also suitable, but little fuel will be released from them due to an insufficient amount of raw materials. Such volumes of production will not suit you;
• organizing the production of biogas at home, you are unlikely to start heating the tank, but it is necessary to insulate it. Another option is to bury the reactor in the ground by thermally insulating the upper part;
• install a manual stirrer of any design in the reactor, pulling the handle through the top cover. The handle passage assembly must be airtight;
• provide nozzles for supplying and unloading the substrate, as well as for sampling biogas.

Below is a diagram of a biogas plant located below ground level:

1 - fuel generator (tank made of metal, plastic or concrete); 2 - bunker for pouring the substrate; 3 - technical hatch; 4 - a vessel that plays the role of a water seal; 5 - branch pipe for unloading waste; 6 – biogas sampling pipe.

How to get biogas at home?

The first operation is the grinding of waste to a fraction whose size is not more than 10 mm. So it is much easier to prepare the substrate, and it will be easier for the bacteria to process the raw materials. The resulting mass is thoroughly mixed with water, its amount is about 0.7 l per 1 kg of organic matter. As mentioned above, only clean water should be used. Then the substrate is filled with a do-it-yourself biogas plant, after which the reactor is hermetically sealed.

Several times during the day you need to visit the container to mix the contents. On the 5th day, you can check the presence of gas, and if it appears, periodically pump it out with a compressor into a cylinder. If this is not done in time, then the pressure inside the reactor will increase and fermentation will slow down, or even stop altogether. After 15 days, it is necessary to unload part of the substrate and add the same amount of new. Details can be found by watching the video:

Conclusion

It is likely that a simple biogas plant will not meet all your needs. But, given the current cost of energy resources, this will already be of considerable help in the household, because you do not have to pay for raw materials. Over time, closely engaged in production, you will be able to catch all the features and make the necessary improvements to the installation.