You can mount small installations at home. To digress, I will say that getting biogas with your own hands is not some kind of new invention. Even in ancient times, biogas at home was actively obtained in China. This country is still the leader in terms of the number of biogas plants. But here how to make a biogas plant with your own hands, what is needed for this, how much it will cost - I will try to tell all this in this and subsequent articles.

Preliminary calculation of biogas plant

Before proceeding with the purchase or self-assembly of a biogas plant, it is necessary to adequately assess the availability of raw materials, their type, quality and the possibility of an uninterrupted supply. Not every raw material is suitable for biogas production. Raw materials that do not fit:

• raw materials with a high content of lignin;
• raw materials containing sawdust of coniferous trees (with the presence of resins)
• with humidity exceeding 94%
• rotting manure, as well as raw materials with mold or synthetic detergents.

If the raw material is suitable for processing, then you can proceed to determine the volume of the bioreactor. The total volume of raw materials for the mesophilic mode (biomass temperature ranges from 25-40 degrees, the most common mode) does not exceed 2/3 of the reactor volume. The daily dose is not more than 10% of the total loaded raw materials.

Any raw material is characterized by three important parameters:

• density;
• ash content;
• humidity.

The last two parameters are determined from statistical tables. The raw material is diluted with water taking into account the achievement of 80-92% humidity. The ratio of the amount of water and raw materials can vary from 1:3 to 2:1. This is done to give the substrate the required fluidity. Those. to ensure the passage of the substrate through the pipes and the possibility of mixing it. For small biogas plants, the density of the substrate can be taken equal to the density of water.

Let's try to determine the volume of the reactor using an example.

Let's say the farm has 10 cattle, 20 pigs and 35 chickens. Excrement comes out per day: 55 kg from 1 cattle, from 1 pig - 4.5 kg and 0.17 kg from chicken. The volume of daily waste will be: 10x55 + 20x4.5 + 0.17x35 = 550 + 90 + 5.95 = 645.95 kg. Round up to 646 kg. The moisture content of pig and cattle excrement is 86%, and that of chicken manure is 75%. To achieve 85% moisture content in chicken manure, add 3.9 liters of water (about 4 kg).

It turns out that the daily dose of loading of raw materials will be about 650 kg. Full load of the reactor: OS=10x0.65=6.5 tons, and reactor volume OP=1.5x6.5=9.75 m³. Those. we need a reactor with a volume of 10 m³.

Biogas yield calculation

Table for calculating the yield of biogas depending on the type of raw material.

Type of raw material	Gas output, m³ per 1 kg of dry matter	Gas output m³ per 1 ton at 85% humidity
Cattle manure	0,25-0,34	38-51,5
Pig manure	0,34-0,58	51,5-88
bird droppings	0,31-0,62	47-94
Horse dung	0,2-0,3	30,3-45,5
sheep manure	0,3-0,62	45,5-94

If we take the same example, then multiplying the weight of each type of raw material by the corresponding tabular data and summing up all three components, we get a biogas yield of approximately 27-36.5 m³ per day.

In order to navigate the required amount of biogas, I will say that an average family of 4 people will need 1.8-3.6 m³ for cooking. To heat a room of 100 m² - 20 m³ of biogas per day.

Installation and fabrication of the reactor

A metal tank, a plastic container can be used as a reactor, or it can be built of brick, concrete. Some sources say that the preferred shape is a cylinder, but in square structures built of stone or brick, cracks form due to the pressure of raw materials. Regardless of the shape, material and installation location, the reactor must:

• be water and gas tight. Mixing of air with gas should not take place in the reactor. Between the cover and the body there must be a gasket made of sealed material;
• be thermally insulated;
• withstand all loads (gas pressure, weight, etc.);
• have a hatch for repair work.

The installation and selection of the reactor shape is made for each farm individually.

Fabrication theme do-it-yourself biogas plant very extensive. Therefore, I will focus on this in this article. In the next article, we will talk about the choice of other elements of a biogas plant, prices and where it can be purchased.

Obtaining biogas (methane) is important for owners of livestock and poultry farms. On farms with poultry and large livestock, the issue of waste disposal is always acute. In order to get rid of litter and manure, it is necessary to take care of the collection, removal, disinfection and processing. All these procedures require certain material costs, time and effort.

In order for the process of manure utilization to begin to bring profit, and not losses, it is advisable to think about processing manure into biogas. Domestic biogas from bird and animal droppings is 50-80% methane. This is the same gas that burns in boilers, stoves and is used for cars. Methane is emitted from manure randomly, on its own. If left to rot in the sun for a year, the manure will ferment and release biogas. You only need to optimize this process to increase the amount of methane produced and speed up the production time.

To increase the efficiency of biogas production, it is necessary to accelerate the process of decomposition and fermentation of raw materials. To do this, you need to create the most favorable conditions for the reproduction of the necessary bacteria. To do this, you will need to place manure in a special container - a reactor. At the same time, the container must be closed - in such conditions, bacteria will multiply more actively. Already in the reactor, the manure is crushed, and then mixed with water. Water must be clean. Otherwise, foreign microbes will get into the substrate, which can slow down the fermentation process.

In industrial conditions, it is equipped with a reactor heating system, an acidity controller and special blades for mixing the substrate. Stirring manure allows you to get rid of the formation of a hard crust, which blocks the flow of oxygen from the outside and the exit of methane from the inside. The term for obtaining methane in industrial conditions is at least fifteen days. During this time, manure can decompose up to 25%. The maximum outflow of methane occurs at a degree of decomposition of 33%.

It should be noted that rotten sludge forms on the bottom of the reactor. It is removed using a special tube, which takes it to a separate tank for sludge. Subsequently, the sludge is cleaned and removed. The methane rising up the tank is cleaned in a steam bath, and then sent to the gas collector.

Industrial production of methane involves the daily injection of fresh substrate, which is mixed with what has already begun to ferment. For a day, you can add 5% fresh manure instead of 5% waste. The manure removed from the reactor can be used as soil fertilizer. So you will have a waste-free production, where you can get both biogas and fertilizers.

Setting up a manure biogas plant at home

To construct a plant for the processing of manure into biogas, you will need:

• hermetically closing container (made of metal, concrete, plastic) with a volume of at least one cubic meter;
• cover for the reactor with a sealed passage for the stirrer handle;
• material for thermal insulation of the bottom (plays the role of a heating system);
• hand mixer from improvised materials (you can use a shovel or screw auger);
• branch pipes for supply/extraction of the substrate and for biogas output.

During the construction process, you may need additional materials: pipes, filters, valves. All this can be found in the hardware store. The design is quite simple, and you can improve it as you build it.

As an experiment, you can try to make an installation from an ordinary plastic barrel. They are produced in volumes from 100 to 200 liters. The barrel will serve as a reactor. Make two holes in it for the inlet and outlet of the pipes. The inlet is made closer to the bottom, and the outlet is made from above. The diameter of the holes depends on the diameter of the nozzles used. Plastic pipes can be bought at a hardware store. We insert them into the holes and securely isolate them. An inlet pipe with a bend (with a connector) is suitable, and a short straight pipe is suitable for the outlet.

The role of the reservoir for the resulting biogas is given to a smaller capacity. For example, you can take a bucket with a volume of 20 liters. The bucket is fixed with a plumbing valve. From it we take the tube to a metal holder with a valve, from where the gas will be released.

Do not forget about the thermal insulation of the barrel. It can be wrapped with mineral wool, polyethylene foam or any other material. It is best to put the barrel in the sun to increase the temperature inside the reactor. We fall asleep inside the raw materials in the ratio of 0.7 liters of water per 1 kg of manure. We put any suitable container for removing sludge, put a bucket on top and wait for fermentation. We are waiting for about three weeks for the first batch of our home biogas. Remember that methane must be cleaned of carbon dioxide before use. A special filter, which is sold in the store as a "filter for cleaning compressed air, carbon dioxide and steam", will cope with this task.

Do-it-yourself biogas from manure: building an underground plant

Another easy way to build your own manure-to-biogas plant is to build an underground system. First you need to dig a hole with a volume of at least one cubic meter. Its walls and bottom are filled with expanded clay concrete. From opposite walls, one pipe is output for supplying biomass and removing sludge. The outlet pipe should be located closer to the bottom, and the inlet pipe should be 50 cm above the bottom. The end of the outlet pipe is brought to the waste container. The end of the inlet pipe should be located in such a way that it is convenient for you to pump new raw materials through it.

The upper part of this "bunker" is a domed or cone-shaped gas tank. It is easiest to make it from metal sheets or brickwork. At the top of the gas tank, a sealed hatch and a gas pipe with a water seal are mounted. We advise you to provide for the presence of such an important part as a pressure relief valve. It will ensure safety when working with the installation and will maintain optimal pressure inside the reactor.

The mixing of the substrate in such an installation occurs according to the principle of bubbling. To do this, take a few plastic pipes and make as many holes in them as possible. Then fix the pipes inside the reactor in a vertical position. When the gas rises, it will emit bubbles, which at the exit will begin to boil in the substrate, thereby mixing it.

Biogas from manure - a profitable investment

For those who are not ready to make such a camera, there is always another way out - you can buy a ready-made one. The construction of the installation will still require a small investment from you. If you are not confident in your abilities or do not have all the materials, it is advisable to simply buy a PVC installation. As a result, you still organize your home production for manure processing and biogas production.

Here in Serbia, and in Europe as a whole, people do not want to depend on energy and gas companies, so they seek to purchase alternative energy sources. Whether it's solar panels, thermal collectors, or biogas plants.

I once talked about biogas plants for industrial production in my magazine, now my story is about a home-made plant that can produce gas for your home or summer cottage. The principle of operation is clear from the figure. I will only make explanations and report the purpose of some elements.

To make the installation you will need:

* Two plastic barrels of 200 liters each (in Serbia, cabbage is salted in such barrels), but there may also be metal barrels from diesel fuel.

* Five adapter fittings for connecting elements with a hose with a thickness of at least 13 mm.

* Plastic hose (length depending on installation needs).

* Plastic bucket.

* Plastic canister 3 - 5 liters (from car oil with screw cap) for emergency valve.

* Two plastic tubes with a diameter of 5 cm.

Element 1 - in the figure, BIO gas generator

It consists of a sealed shaft, two plastic pipes and a biogas outlet.

In the generator, the organic matter will decompose as it rots, releasing 60% methane and 40% SO2.

Through the first plastic tube with a funnel, finely chopped biomass waste is poured, mixed with water in a ratio of 10% biomass and 90% rainwater (soft water).

It would be nice if we could also add a natural mixture of fresh manure from cows, pigs and poultry, in order to introduce the microorganisms on which the production of biogas depends. If not available, you can add some mud from a river or pond to speed up the process.

The process takes about 3 weeks for the gas to form. Early on, you will notice that gas is being released, but be aware that it is SO2 - carbon dioxide, which is not combustible. Only after 3 weeks have passed does the formation of methane - biogas - occur.

At the bottom of the container, over time, a residue appears, which is an excellent natural fertilizer for vegetables in horticulture.

The ideal temperature is between 12 and 36 degrees, protect the barrel from direct sunlight in the shade, and from freezing in winter. Keep in mind that this is a "live" barrel, meaning it contains billions of microorganisms working on the biomass decomposition process.

If you "overcook" or "freeze" the BIO Gas Generator, microorganisms will disappear, so the whole process will have to be started again.

Element 2 in the figure is a container for collecting biogas and a water seal

It consists of an open plastic barrel, a bucket and two fittings. (valve) for gas flow and weight (tags).

In this container - a barrel of 200 liters, gas is collected, as shown in the figure. Provides a simple and flexible solution without wasting gas. In addition, water also acts as a filter, purifying methane from impurities.

Note that the gas has lifted the water container and this indicates the amount of gas collected.

The weight of the weight will help to make the pressure of the gas sufficient, which is then sent to the emergency valve, element number 4.

Keep this container filled with water and protected from freezing.

Element 3 - burner

Element 4 - Emergency valve

The emergency valve consists of a plastic water canister with a screw cap and two adapters.

Empty oil cans for a car are a good improvisation.

The safety valve is designed to intercept the flame in order to stop the backfire. The safety valve is located between Element 3 - the burner and the gas collection container, Element 2.

It is imperative that you install an emergency valve to prevent the possibility of the gas container being ignited, resulting in an accident or explosion.

Many household owners are concerned about how to cut home heating, cooking and electricity costs. Some of them have already built biogas plants with their own hands and partially or completely separated themselves from energy suppliers. It turns out that getting almost free fuel in a private household is not very difficult.

What is biogas and how can it be used?

Owners of household plots know that by putting together any vegetable raw materials, bird droppings and manure, after a while you can get valuable organic fertilizer. But few of them know that biomass does not decompose by itself, but under the influence of various bacteria.

Processing the biological substrate, these tiny microorganisms release waste products, including a gas mixture. Most of it (about 70%) is methane - the same gas that burns in the burners of household stoves and heating boilers.

The idea of ​​using such eco-fuels for various household needs is not new. Devices for its extraction were used in ancient China. The possibility of using biogas was also explored by Soviet innovators in the 60s of the last century. But the technology experienced a real revival in the early 2000s. At the moment, biogas plants are actively used in Europe and the USA for heating houses and other needs.

How does a biogas plant work?

The principle of operation of the device for the production of biogas is quite simple:

• biomass diluted with water is loaded into a sealed container, where it begins to “ferment” and release gases;
• the contents of the tank are regularly updated - the raw materials processed by bacteria are drained and fresh ones are added (on average, about 5-10% daily);
• the gas accumulated in the upper part of the tank is supplied through a special tube to the gas collector, and then to household appliances.

Diagram of a biogas plant.

Which raw material is suitable for bioreactor?

Biogas plants are profitable only where there is a daily replenishment of fresh organic matter - manure or droppings from livestock and poultry. Also, crushed grass, tops, leaves and household waste (in particular, vegetable peelings) can be mixed into the bioreactor.

The efficiency of the installation largely depends on the type of feedstock. It has been proven that with the same mass, the largest biogas yield is obtained from pig manure and turkey manure. In turn, cow dung and silage produce less gas for the same load.

The use of bio-raw materials for home heating.

What cannot be used in a biogas plant?

There are factors that can significantly reduce the activity of anaerobic bacteria, or even completely stop the process of biogas production. Do not allow raw materials containing:

• antibiotics;
• mold;
• synthetic detergents, solvents and other "chemistry";
• resins (including sawdust of coniferous trees).

It is inefficient to use already rotting manure - only fresh or pre-dried waste is to be loaded. Also, waterlogging of raw materials should not be allowed - an indicator of 95% is already considered critical. However, it is still necessary to add a small amount of pure water to the biomass in order to facilitate its loading and speed up the fermentation process. Dilute manure and waste to the consistency of thin semolina.

Biogas plant for home

Today, the industry is already producing plants for biogas production on an industrial scale. Their purchase and installation is expensive, such equipment in private households pays off no earlier than in 7-10 years, provided that large volumes of organic matter are used for processing. Experience shows that, if desired, a skilled owner can build a small biogas plant for a private house with his own hands, and from the most affordable materials.

Preparing a processing bunker

First of all, you need a hermetically sealed cylindrical container. You can, of course, use large pots or boils, but their small volume does not allow sufficient gas production to be achieved. Therefore, for these purposes, plastic barrels with a volume of 1 m³ to 10 m³ are most often used.

You can make one yourself. PVC sheets are commercially available, with sufficient strength and resistance to aggressive environments, they are easily welded in the design of the desired configuration. A metal barrel of sufficient volume can also be used as a bunker. True, it will be necessary to carry out anti-corrosion measures - to cover it from the inside and outside with moisture-resistant paint. If the tank is made of stainless steel, this is not necessary.

Gas exhaust system

The gas outlet is mounted in the upper part of the barrel (usually in the lid) - this is where it accumulates, according to the laws of physics. Through a connected pipe, biogas is supplied to a water seal, then to a storage tank (as an option, using a compressor into a cylinder) and to household appliances. It is also recommended to install a release valve near the gas outlet - if the pressure inside the tank becomes too high, it will release excess gas.

Feeding and unloading system of raw materials

To ensure the continuous production of the gas mixture, the bacteria in the substrate must be constantly (daily) “feeded”, that is, fresh manure or other organic matter must be added. In turn, already processed raw materials must be removed from the bunker so that it does not take up useful space in the bioreactor.

To do this, two holes are made in the barrel - one (for unloading) is almost near the bottom, the other (for loading) is higher. Pipes with a diameter of at least 300 mm are welded (soldered, glued) into them. The loading pipeline is directed upwards and equipped with a funnel, and the drain is equipped so that it is convenient to collect the processed slurry (it can later be used as fertilizer). Joints are sealed.

heating system

Bunker insulation.

If the bioreactor is installed outdoors or in an unheated room (which is necessary for safety reasons), then it must be provided with thermal insulation and heating of the substrate. The first condition is achieved by "wrapping" the barrel with any insulating material or a recess in the ground.

As for heating, here you can consider a variety of options. Some craftsmen lead pipes inside, through which water from the heating system circulates and mount them along the walls of the barrel in the form of a coil. Others place the reactor in a larger tank with water inside, heated by electric heaters. The first option is more convenient and much more economical.

To optimize the operation of the reactor, it is necessary to maintain the temperature of its contents at a certain level (at least 38⁰C). But if it rises above 55⁰C, then the gas-producing bacteria will simply “cook” and the fermentation process will stop.

Mixing system

As practice shows, in designs, a hand stirrer of any configuration significantly increases the efficiency of the bioreactor. The axis, to which the blades of the “mixer” are welded (screwed), is output through the barrel lid. A gate handle is subsequently put on it, the hole is carefully sealed. However, home craftsmen do not always equip fermenters with such devices.

Biogas production

After the installation is ready, it is loaded with biomass, diluted with water in a ratio of approximately 2:3. In this case, large waste must be crushed - the maximum fraction size should not exceed 10 mm. Then the lid closes - it remains to wait for the mixture to begin to "ferment" and release biogas. Under optimal conditions, the first flow of fuel is observed a few days after loading.

The fact that the gas "went" can be judged by the characteristic gurgling in the water seal. At the same time, the barrel should be checked for leaks. This is done using an ordinary soapy solution - it is applied to all joints and observed to see if bubbles have appeared.

The first update of bio-raw materials should be carried out in about two weeks. After the biomass is poured into the funnel, the same volume of spent organics will pour out of the outlet pipe. Further, this procedure is performed daily or every two days.

How much biogas is produced?

In a small farm, a biogas plant will not become an absolute alternative to natural gas and other available energy sources. For example, using a device with a capacity of 1 m³, you can get fuel for only a couple of hours of cooking for a small family.

But with a bioreactor of 5 m³ it is already possible to heat a room of 50 m², but its work will need to be supported by a daily load of raw materials weighing at least 300 kg. To do this, you need to have about ten pigs, five cows and a couple of dozen chickens on the farm.

Masters who managed to independently make existing biogas plants share videos with master classes on the Internet:

You can get a cheap source of energy yourself, at home - you just need to assemble a biogas plant. If you understand the principle of its functioning and device, then this is not difficult to do. The mixture produced by it contains a large amount of methane (depending on the feedstock - up to 70%), so it has a wide scope.

Refueling car cylinders running on gas as fuel for heating boilers is far from a complete list of all possible options for using the finished product. How to mount a biogas plant with your own hands is our story.

There are several designs of the unit. When choosing one or another engineering solution, you need to understand how this installation is suitable for local conditions. This is the main criterion for assessing the feasibility of installation. Plus, it has its own capabilities, that is, what type of raw materials and in what volume it will be possible to use, what you can do with your own hands.

Biogas is produced by the decomposition of organic matter, but its "yield" (in terms of volume), and, therefore, the efficiency of the installation, depends on what exactly is loaded into it. The table provides relevant information (indicative data) that will help determine the choice of a specific engineering solution. Some explanatory charts will also be useful.

Design options

With manual loading of raw materials, without heating and mixing

For domestic use, this model is considered the most convenient. With a reactor capacity of 1 to 10 m³, about 50-220 kg of manure will be needed daily. This is what you need to proceed from, determining the size of the container.

The installation is mounted in the ground, so it will need a small pit. In accordance with its estimated dimensions, a place on the site is selected. The composition and purpose of all elements of the circuit is easy to understand.

Installation feature

After installing the reactor in place, it is necessary to check its tightness. Then the metal is to be painted (preferably with a frost-resistant composition) and insulated.

• Removal of mining occurs naturally - either in the process of laying a new portion, or with an excess of gas in the reactor with the valve closed. Therefore, the capacity of the waste collection container should be no less than that of the working one.
• Despite the simplicity of the device and the attractiveness for do-it-yourself assembly, due to the fact that mass mixing and heating is not provided, it is advisable to operate this installation option in regions with a mild climate, that is, mainly in the south of Russia. Although with high-quality thermal insulation, in conditions where underground water layers are deep, this design is quite suitable for the middle lane.

Without heating, but with stirring

Pretty much the same thing, just a slight modification that significantly increases the performance of the unit.

How to make a mechanism? For someone who collected with his own hands, for example, this is not a problem. The reactor will have to mount a shaft with blades. Therefore, it is necessary to install thrust bearings. It is good to use a chain as a transmission link between the shaft and the lever.

The biogas plant can be operated in almost all regions, with the exception of the northern regions. But unlike the previous model, it requires supervision.

Stirring + heating

Thermal impact on biomass increases the intensity of decomposition and fermentation processes occurring in it. A biogas unit is more versatile in use, as it can operate in two modes - mesophilic and thermophilic, that is, in the temperature range (approximately) 25 - 65 ºС (see graphs above).

In this scheme, the boiler runs on the resulting gas, although this is not the only option. Heating of biomass can be carried out in different ways, as it is more convenient for the owner to organize it.

Automated Options

The difference between this scheme is that it is connected to the installation. This allows you to accumulate gas reserves, and not to spend it immediately for its intended purpose. Ease of use is that almost any temperature regime is suitable for intensive fermentation.

This setup is even more efficient. It is capable of processing up to 1.3 tons of raw materials per day with a similar volume of the reactor. Loading, mixing - pneumatics is "responsible" for this. The discharge channel allows waste to be removed either to a short-term storage bin or to mobile containers for immediate removal. For example, for fertilizing fields.

For domestic use, these variants of a biogas plant are hardly suitable. Their installation, and even with their own hands, is much more difficult. But for a small farm - a good solution.

Mechanized biogas plant

The difference from previous models is in the additional tank, in which the preliminary preparation of the raw mass takes place.

Compressed biogas is fed into the feed hopper and then into the reactor. It is also used for heating.

The only thing that is needed when assembling any of the installations with your own hands is accurate engineering calculations. You may need to consult a specialist. And the rest is pretty simple. If at least one of the readers becomes interested in a biogas unit and mounts it on their own, it means that the author did not work on this article in vain. Good luck!