Money

Do-it-yourself methane generator. DIY home biogas plant

Biogas is one of the products formed during the decomposition of biomass under the influence of certain types of bacteria. It is produced anaerobically, that is, absolutely excluding the presence of air.

In every peasant or farming accumulates over the year a large number of:

Excrement from farm animals;
Tops of field crops;
Other animal and agricultural waste.

All this is an excellent raw material that can be used as an organic fertilizer. Another way to use these wastes is to process them into biogas through fermentation.. Such a product is simply necessary for those who are engaged in agricultural production.

Biogas, in fact, is a mixture of several components, the main of which are:

Methane (from 55 to 70%);
Carbon dioxide (from 28 to 43%);
Hydrogen sulfide and others.

If we take on average, then 1 kg of biological mass, decomposing, releases approximately:

0.18 kg of methane;
0.32 kg of carbon dioxide;
0.2 kg of ordinary water.

The non-degradable residue is only 300g.

Why recycle manure?

Fresh manure, with its liquid constituents, which is not processed in any way, is a problem for the environment. Spreading around the district, interspersed with sewage, it pollutes the territories:

Particularly susceptible crops simply die from manure masses in the ground;
The air is polluted, acquiring a specific smell;
The soil becomes infected with pathogens.

Worms and bacteria living in manure continue to exist there and actively multiply. Weed seeds, being resistant to adverse effects, fall from manure into the soil and germinate safely. To avoid such consequences, a special technology for processing biological mass was needed, which

Increases the content of useful components;
Eliminates the harmful effects on the environment, including the development and reproduction of pathogenic microorganisms.

The most promising and cost-effective direction in this regard was the anaerobic processing of manure and other waste. organic origin in order to obtain biogas!

Use of biogas

The possibilities of using biogas are extremely wide. By means of special cogeneration plants, it can be turned into electricity and a source of thermal energy, while the electric resource is supplied to common network, and use the heat for heating:

Buildings for industrial purposes;
Residential buildings;
Premises where farm animals are kept.

A good alternative worth considering is considered unique technology, at which the quality indicators of biological gas are brought to the level of natural gas. In this case, the resulting gas product can be fed into the network and successfully used. The technology allows the resource to be transported over considerable distances in order to use it in the interests of consumers.

Biogas in global energy

Statistics state that the share of biogas in the global energy sector, obtained from agricultural waste, is almost 12%, although initially the idea of its production and use was not aimed at obtaining significant commercial benefits.

To this day, a large amount of biological raw materials that are used to generate energy do not belong to the category of commercial products and are not taken into account at all by official statistics.

If we talk about the EU countries, then the share of biomaterials in the energy sector in general reaches 3%, while:

Austria is 12% of the national energy industry;
Sweden - up to 18%;
Finland - about 23%.

Feedstock for biogas production

Maize, grass and rye silos can be used as feedstock for biogas production, among others. Crops such as sugar beets and sunflowers are well suited for these purposes. In production, you can use such types of organic waste that have no other use.

Calculation of the volume of the finished product

The calculation of the daily volume of biogas depends on the type of feedstock and the daily amount of its loading.

As an example, you can take a small farm, which includes:

large cattle(cattle) - 10 goals;
Pigs - 20;
Chickens - 35.

Knowing the daily volume of excrement received from each animal, it is possible to derive the amount of this raw material per day, taking into account the livestock:

Cattle - 10 heads x 55 kg = 550 kg (with 85% humidity);
Pigs - 20 heads x 4.5 kg = 90 kg (with the same moisture index as cattle);
Chickens - 35 heads x 0.17 kg = 5.95 kg (at 75% humidity).

If you add water to chicken manure, bringing the moisture content to the desired 85%, you get 10 kg of raw materials.

The amount of biological gas obtained from a kilogram of excremental source material will then be:

Cattle manure - from 0.04 to 0.05 m3;
Pig manure - from 0.05 to 0.09 m3;
Chicken manure - from 0.05 to 0.09 m3.

Accordingly, the total volume will be:

From 550 kg of cattle manure - 22 - 27.5 m3;
From 90 kg of pig manure - 4.5–8.1 m3;
From 10 kg of chicken manure - 0.5–0.9 m3.

Total: from 27 to 36.5 m3 of biogas per day.

As a result of utilization, a liquid substance with many useful properties is formed, which is suitable for fertilizing areas where forage grasses and vegetables grow.

Dry fertilizer increases yield:

Alfalfa - up to 50%;
Corn - up to 12%;
Vegetable crops - up to 30.

The device and features of equipment for the production of biogas

When choosing a processing plant, it is important not to forget about maintaining the moisture content of the raw materials. For optimal results, a water addition function is desirable.

When loading raw materials, water is automatically added to the container at the rate of 1:8. To make the mass homogeneous and evenly distributed, it is mixed with a special pump.

After a given period of time, the manure mass, being continuously mixed, is transferred to the bioreactor. As soon as the capacity of the receiver is empty, the mixing process stops automatically.

When loading vegetable raw materials (for example, corn silage), biogas plants operate without interruption, following a two-stage technology.

Such equipment includes:

Fermenter;
Tank for secondary fermentation;
Storage.

This makes it possible to achieve high stability and reliability of the installation.

In the fermentation tank, the same conditions for the activity of beneficial bacteria are created as in the fermenter.

Thus, the maximum production of biogas from slowly decaying substrates is ensured, because at the second stage 20% of its possible production is released.

Schemes of action by technology and design indicators of a biogas plant are directly dependent on:

Quantity and properties of the source material;
Mode of heat and humidity;
Methods of loading and features of fermentation;
other factors.

The main equipment of the installation are:

A sealed container with a heat exchanger, where the heat carrier is water heated from 50 to 60 degrees;
A device through which manure enters and exits;
Device for removal of biogas.

Of course, it would be easier to create a universal bioreactor. But this is impossible, because each household uses its own bedding material and its own method of heat supply. The design of a biogas plant is largely determined by local features and materials.

Let us consider in more detail the processes that occur in the bioreactor. The entire installation complex consists of three sections:

- - 1. Boot;
    2. Working;
    3. unloading.

The inner surface of the reactor is a tubular plastic container. Such a structure is necessary for the processes to take place fully and to the maximum extent.

The reactor communicates with the receiving vessel through a technological hatch, which opens at the right moment, namely when the biomass, having mixed with water, acquires a homogeneous consistency.

The upper part of the working compartment also has a hermetically sealed technological hatch, on the surface of which there are devices for monitoring the amount of biomass, sampling the formed gas and measuring its pressure. When it rises, the compressor is automatically activated and the gas is pumped out into the gas tank. This avoids damage and rupture of the container.

The structure of the bioreactor has an additional heating element responsible for temperature regime in the process of fermentation. In the second half of the reactor, the heating is higher. This is important to ensure the chemical reaction and maximize the yield of the finished product.

The mass is subjected to continuous mixing so that a floating crust does not form - it can interfere with the outgoing gas. At the end of fermentation, the biomixture is unloaded into the appropriate sector, where the final separation of gas residues from the liquid part takes place.

Many of those who own such installations use manure or its slurry as raw material for processing. MT-Energie presents its new development– a single-stage slurry biogas plant, which includes only the fermenter and storage, excluding the fermentation tank. Its absence is due to the fact that the fermentation of slurry from manure is faster than a similar process using silage. New installation is more cost-effective and attractive in terms of its price characteristics.

Due to the predominance of the proportion of slurry, the substrate in the fermenter does not have a significant potential for gas formation, so the construction of a tank intended for subsequent fermentation is not advisable.

Many such installations function, and the heat generated in this case is not used. The solution of this issue could significantly increase the efficiency of the equipment. Most often this is due to the peculiarities of the location, because the complexes are not always built in industrialized areas.

Therefore, obtaining electricity from biogas directly at the plant is not always justified. A more preferable option is the generation of electricity near the direct consumer, so that heat can be used along with it.

An existing gas supply network is ideal for transporting the final product. In order for biological gas to reach the level of natural blue fuel in terms of its indicators, it needs additional purification.

The technology is not new. It began to develop back in the 18th century, when Jan Helmont, a chemist, discovered that manure emits gases that are capable of igniting.

His research was continued by Alessandro Volta and Humphry Devi, who found methane in the gas mixture. At the end of the 19th century in England, biogas from manure was used in street lamps. In the middle of the 20th century, bacteria were discovered that produce methane and its precursors.

The fact is that three groups of microorganisms alternately work in manure, which feed on the waste products of previous bacteria. Acetogenic bacteria are the first to start working, which dissolve carbohydrates, proteins and fats in slurry.

After processing by anaerobic microorganisms nutrient reserve methane, water and carbon dioxide are produced. Due to the presence of water, biogas at this stage is not able to burn - it needs cleaning, so it is passed through the treatment plant.

What is biomethane

The gas obtained as a result of the decomposition of manure biomass is an analogue of natural gas. It is almost 2 times lighter than air, so it always rises. This explains the technology of production by an artificial method: they leave free space at the top so that the substance can be released and accumulated, from where it is then pumped out by pumps for use in their own needs.

Methane strongly contributes to the occurrence of the greenhouse effect - much more than carbon dioxide - 21 times. Therefore, manure processing technology is not only an economical, but also an environmentally friendly way to dispose of animal waste.

Biomethane is used for the following needs:

cooking;

in internal combustion engines of cars;

for heating a private house.

Biogas releases a lot of heat. 1 cubic meter is equivalent to burning 1.5 kg of coal.

How is biomethane produced?

It can be obtained not only from manure, but also from algae, plant mass, fat and other animal waste, the remains of the processing of raw materials from fish shops. Depending on the quality of the source material, its energy capacity, the final output of the gas mixture depends.

The minimum is obtained from 50 cubic meters of gas per ton of cattle manure. Maximum - 1,300 cubic meters after processing animal fat. The content of methane in this case is up to 90%.

One of the types of biological gas is landfill gas. It is formed during the decomposition of garbage in suburban landfills. The West already has equipment that processes the waste of the population and turns it into fuel. As a type of business, these are unlimited resources.

Under its raw material base fall:

food industry;

animal husbandry;

poultry farming;

fishing and processing plants;

dairies;

production of alcoholic and low-alcohol drinks.

Any industry is forced to dispose of its waste - it is expensive and unprofitable. At home, with a small homemade installation several problems can be solved at once: free heating at home, fertilizer land plot high-quality nutrient left over from manure processing, freeing up space and odor free.

Biofuel technology

All bacteria that take part in the formation of biogas are anaerobic, that is, they do not need oxygen for life. For this, completely sealed fermentation tanks are constructed, the outlet pipes of which also do not allow air to pass through from the outside.

After pouring the raw liquid into the tank and raising the temperature to the desired value, the bacteria begin to work. Methane begins to be released, which rises from the surface of the slurry. It is sent to special pillows or tanks, after which it is filtered and enters gas cylinders.

The liquid used by bacteria accumulates at the bottom, from where it is periodically pumped out and also sent for storage. After that, a new portion of manure is pumped into the tank.

The temperature regime of the functioning of bacteria

For the processing of manure into biogas, it is necessary to create suitable conditions for the bacteria to work. some of them are activated at temperatures above 30 degrees - mesophilic. Wherein the process is underway slower and the first production can be obtained in 2 weeks.

Thermophilic bacteria work at temperatures from 50 to 70 degrees. The terms for obtaining biogas from manure are reduced to 3 days. In this case, the waste is a fermented sludge, which is used in the fields as a fertilizer for crops. There are no pathogenic microorganisms, helminths and weeds in the sludge, as they die when exposed to high temperatures.

There is special kind thermophilic bacteria that can survive in an environment heated to 90 degrees. They are added to raw materials to speed up the fermentation process.

Lowering the temperature leads to a decrease in the activity of thermophilic or mesophilic bacteria. In private households, mesophylls are more often used, since they do not need to specially heat the liquid and gas production is cheaper. Subsequently, when the first batch of gas is obtained, it can be used to heat the reactor with thermophilic microorganisms.

Important! Methanogens do not tolerate sudden changes in temperature, so in winter they must be kept warm all the time.

How to prepare raw materials for pouring into the reactor

For the production of biogas from manure, it is not necessary to specifically add microorganisms to the liquid, because they are already in animal excrement. It is only necessary to maintain the temperature regime and add a new manure solution in time. It must be properly prepared.

The humidity of the solution should be 90% (consistency of liquid sour cream), therefore, dry types of excrement are first filled with water - rabbit droppings, horse, sheep, goat. Pig manure in its pure form does not need to be diluted, as it contains a lot of urine.

The next step is to break up the manure solids. The smaller the fraction, the better the bacteria will process the mixture and the more gas will be the output. To do this, in the installations, a stirrer is used, which is constantly working. It reduces the risk of a hard crust forming on the liquid surface.

For the production of biogas, those types of manure that have the highest acidity are suitable. They are also called cold - pork and cow. The decrease in acidity stops the activity of microorganisms, so it is necessary to monitor at the beginning how long it takes for them to completely process the volume of the tank. Then add the next dose.

Gas treatment technology

When processing manure into biogas, it turns out:

70% methane;

30% carbon dioxide;

1% impurities of hydrogen sulfide and other volatile compounds.

In order for biogas to become suitable for use on the farm, it must be purified from impurities. Special filters are used to remove hydrogen sulfide. The fact is that volatile hydrogen sulfide compounds, when dissolved in water, form an acid. It contributes to the appearance of rust on the walls of pipes or tanks, if they are made of metal.

The resulting gas is compressed under a pressure of 9 - 11 atmospheres.

It is fed into a water tank where the impurities are dissolved in the liquid.

On an industrial scale, lime or activated carbon is used for cleaning, as well as special filters.

How to reduce moisture content

There are several ways to get rid of water impurities in gas on your own. One of them is the principle of moonshine. The gas flows upward through the cold pipe. The liquid condenses and flows down. To do this, the pipe is carried underground, where the temperature naturally decreases. As it rises, the temperature also rises, and the dried gas enters the storage.

The second option is a water seal. After exiting, the gas enters a container with water and is purified from impurities there. This method is called a one-stage method, when biogas is cleaned immediately from all volatile substances and moisture with the help of water.

Water seal principle

What installations are used to produce biogas

If the installation is planned to be located near the farm, then the best option would be a collapsible design that is easy to transport to another location. The main element of the installation is a bioreactor, into which raw materials are poured and the fermentation process takes place. Large enterprises use tanks volume of 50 cubic meters.

Private farms build underground tanks as a bioreactor. They are laid out of brick in a prepared pit and coated with cement. Concrete increases the safety of the structure and prevents air from entering. The volume depends on how much raw material is received from pets per day.

Surface systems are also popular in the home. If desired, the installation can be disassembled and moved to another location, unlike a stationary underground reactor. As a tank, plastic, metal or polyvinyl chloride barrels are used.

By type of management there are:

automatic stations in which topping up and pumping out of waste raw materials is carried out without human intervention;

mechanical, where the entire process is controlled manually.

With the help of a pump, it is possible to facilitate the emptying of the tank into which the waste after fermentation enters. Some craftsmen use pumps to pump gas from pillows (for example, car chambers) to a treatment plant.

Scheme of a home-made plant for producing biogas from manure

Before building a biogas plant in your area, you should be familiar with the potential hazard that could blow up the reactor. The main condition is the absence of oxygen.

Methane is an explosive gas and it can ignite, but for this it must be heated above 500 degrees. If the biogas is mixed with air, an overpressure will develop that will rupture the reactor. Concrete may crack and will not be suitable for further use.

Video: Biogas from bird droppings

To prevent the pressure from tearing off the lid, a counterweight is used, a protective gasket between the lid and the tank. The container is not completely filled - there should be at least 10% volume for gas outlet. Better - 20%.

So, in order to make a bioreactor with all the devices on your site, you need:

It is good to choose a place so that it is away from housing (you never know what).

Calculate the estimated amount of manure that animals give out daily. How to count - read below.

Decide where to lay the loading and unloading pipe, as well as a pipe for condensing moisture in the resulting gas.

Decide on the location of the waste tank (default fertilizer).

Dig a pit, based on the calculations of the amount of raw materials.

Choose a container that will serve as a reservoir for manure and install it in the pit. If a concrete reactor is planned, then the bottom of the pit is poured with concrete, the walls are laid out with bricks and plastered with concrete mortar. After that, you need to give time to dry.

The joints between the reactor and the pipes are also sealed at the stage of laying the tank.

Equip a hatch for inspection of the reactor. An airtight seal is placed between it.

If the climate is cold, then before concreting or installing a plastic tank, they think over ways to heat it. These can be heating devices or a tape used in the "warm floor" technology.

At the end of the work, check the reactor for leaks.

Calculation of the amount of gas

About 100 cubic meters of gas can be obtained from one ton of manure. The question is how much litter do pets give per day:

chicken - 165 g per day;

cow - 35 kg;

goat - 1 kg;

horse - 15 kg;

sheep - 1 kg;

pig - 5 kg.

Multiply these figures by the number of heads and you get the daily dose of excrement to be processed.

More gas is obtained from cows and pigs. If you add such energetically powerful plants as corn, beet tops, millet to the mixture, then the amount of biogas will increase. Big potential in marsh plants and algae.

The highest is in the waste of meat processing plants. If there are such farms nearby, then you can cooperate and install one reactor for all. The payback period of the bioreactor is 1-2 years.

Waste biomass after gas production

After processing manure in the reactor, the by-product is biosludge. During anaerobic waste processing, bacteria dissolve about 30% of organic matter. The rest stands out unchanged.

The liquid substance is also a by-product of methane fermentation and is also used in agriculture for root dressings.

Carbon dioxide is a waste fraction that biogas producers seek to remove. But if you dissolve it in water, then this liquid can also be beneficial.

Full use of biogas plant products

To fully utilize the products obtained after manure processing, it is necessary to maintain a greenhouse. Firstly - organic fertilizer can be used for year-round cultivation of vegetables, the yield of which will be stable.

Secondly, carbon dioxide is used as top dressing - root or foliar, and its output is about 30%. Plants absorb carbon dioxide from the air and at the same time grow better and gain green mass. If you consult with experts in the field, they will help install equipment that converts carbon dioxide from a liquid form to a volatile substance.

Video: Biogas in 2 days

The fact is that for the maintenance of a livestock farm, there can be a lot of energy resources received, especially in summer, when there is no need to heat a cowshed or a pigsty.

Therefore, it is recommended to engage in another profitable activity - an environmentally friendly greenhouse. The rest of the products can be stored in refrigerated rooms - due to the same energy. Refrigeration or any other equipment can run on electricity generated by a gas battery.

Use as a fertilizer

In addition to generating gas, the bioreactor is useful in that the waste is used as a valuable fertilizer, which retains almost all of the nitrogen and phosphates. When manure is introduced into the soil, 30-40% of nitrogen is irretrievably lost.

To reduce the loss of nitrogen substances, fresh excrement is introduced into the soil, but then the released methane damages root system plants. After manure processing, methane is used for own needs, and all nutrients are preserved.

Potassium and phosphorus after fermentation pass into a chelate form, which is absorbed by plants by 90%. When viewed in general, then 1 ton of fermented manure can replace 70 - 80 tons of ordinary animal excrement.

Anaerobic processing preserves all the nitrogen in manure, converting it into ammonium form, which increases the yield of any crop by 20%.

Such a substance is not dangerous for the root system and can be applied 2 weeks before planting crops in open ground so that organic matter has time to be processed this time by soil aerobic microorganisms.

Before use, biofertilizer is diluted with water in a ratio of 1:60. Both dry and liquid fractions are suitable for this, which, after fermentation, also enters the waste raw materials tank.

From 700 to 1,000 kg/l of undiluted fertilizer is needed per hectare. Considering that from one cubic meter If the area of the reactor is up to 40 kg of fertilizer per day, then in a month you can provide not only your site, but also your neighbor's, selling organic matter.

What nutrients can be obtained after working out manure

The main value of fermented manure as a fertilizer is in the presence of humic acids, which, as a shell, retain potassium and phosphorus ions. Being oxidized in air during long-term storage, microelements lose their useful qualities, but, on the contrary, they acquire them during anaerobic processing.

Humates have a positive effect on the physical and chemical composition of the soil. As a result of the introduction of organic matter, even the most heavy soils become more permeable to moisture. In addition, organic matter is food for soil bacteria. They further process the remnants that the anaerobes have not eaten and release humic acids. As a result of this process, plants receive nutrients that are completely absorbed.

In addition to the main ones - nitrogen, potassium and phosphorus - there are trace elements in the biofertilizer. But their number depends on the feedstock - vegetable or animal origin.

Sludge storage methods

It is best to store fermented manure in a dry state. This makes it easier to package and transport. Dry matter loses less useful properties and can be stored closed. Although during the year such fertilizer does not deteriorate at all, it must be closed in a bag or container further.

Liquid forms should be stored in closed containers with tight-fitting lids to prevent nitrogen venting.

How to store manure on the plot for fertilizing the garden: the best ways

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 we are talking about 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 Negative influence 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 quality, it approaches traditional look fuel is 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. Maintenance and maintenance of mesophilic plants is cheaper, so 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 quite 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 many options: from ready-made solutions before 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 biogas plant for all.

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 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 pass preliminary training: it is crushed into fractions of not 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 receiving device can be located in the lower side of the container. 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 box rectangular shape. 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 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.

At vertical arrangement 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. Used in stationary installations automated systems heating, which are switched on when the temperature drops below a predetermined level, and are turned off when the required temperature is reached.

For heating, you can use gas boilers, direct heating with electric heaters, or built into the base of the tank a heating element. 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

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 average temperature 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 tank).

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 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 at a distance of approximately 50 cm from the bottom and has a diameter of 25-35 cm. The upper part of the pipe enters the compartment for receiving raw materials.

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.

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.

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 ready installation or contact the experts. published

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.

The mechanism of gas formation from organic raw materials

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, 1 m 3 of biogas emits as much heat as is obtained by burning one and a half kilograms of coal.

Actually, these are the two main conditions that contribute to the miraculous transformation of rotting manure mass into environmentally friendly fuel and valuable fertilizers.

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

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 effectiveness 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, it is necessary to carefully calculate everything

Maintenance and maintenance of mesophilic plants is cheaper, so most farms use them to produce biogas.

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 m 3 of biogas, from which, in turn, 3 kWh of electricity can be generated.

Using the data from the table, it is not difficult to calculate how many m 3 of biogas can be obtained at the output in accordance with the number of livestock available on the farm

In two weeks, the free fuel is ready. This small installation produced 40 m 3 of gas per day, which was quite enough to heat the house and outbuildings for six months.

Options for Biofuel Plants

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 option is suitable, which is easy to make from improvised means with your own hands.

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 many 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 biogas plant for all.

A mini-plant for the production of gas to cover the needs of a small private household can be made with your own hands, focusing on the design and specifics of the installation of installations produced on an industrial scale.

The design of plants for the processing of manure and plant organic matter into biogas is not complex. The original produced by the industry is quite suitable as a template for building your own mini-factory

Independent craftsmen who decide to start building their own installation need to stock up on a water tank, water or sewer plastic pipes, corner bends, seals and a cylinder for storing the gas obtained in the installation.

Image gallery

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 principle of operation of the installation

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.

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%.

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 should 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 substrate, which flows into the reactor, at the same time the same amount of spent mass rises through the pipe to the waste receiver, from where it is subsequently scooped out and used as a high-quality bio-fertilizer.

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.

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.

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, direct heating with electric heaters or build a heating element into the base of the tank.

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

Determination of the required volume

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.

Construction of an underground structure

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 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.

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:

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

Biogas is a mixture of gases that are formed during the decomposition process organic matter anaerobic bacteria. Biogas is highly flammable, it forms a clean flame when burned, so it can be used not only for cooking, but also for internal combustion engines (for example, for the production of electricity).

Advantages of a biogas plant at home:
- you can easily get biogas at home without the use of expensive equipment;
- an excellent alternative energy for those whose housing is located far from civilization, or for those who wish to be independent of the state;
– available raw materials (manure, kitchen waste, shredded vegetation, etc.);
- taking care of environment, since in the process of decomposition of organic substances in nature, the gas enters the atmosphere, which entails the greenhouse effect, and in this case, biogas will be burned, while receiving CO2;
– obtaining fertilizers as a by-product of a biogas plant.

But apart from the advantages, biogas plant has its drawbacks:
- bacteria work at a temperature of 18-40 degrees, so you can get biogas in the summer. If the biogas plant is insulated and equipped with heating, then it is possible to obtain biogas in the spring-autumn period, but the costs of insulation and heating may negate the benefit
- it is necessary to constantly introduce new raw materials, and therefore drain fertilizers.

To make a biogas plant with our own hands, we need:
1. Two barrels for 200l
2. Barrel for 30-60 liters, or a large plastic bucket
3. Plastic sewer pipes
4. Gas hose
5. Faucet

For clarity, I will diagram of a home biogas plant

The principle of operation of a biogas plant. Raw materials (manure, kitchen waste, chopped vegetation, etc.) and water are loaded into the reactor. The biogas plant will not work immediately, but after a few days, when the number of anaerobic bacteria will increase to a maximum.

During the life of anaerobic bacteria, biogas is released, which will be collected at the top of the barrel (a tap should be located in this place). From the reactor, biogas enters the collector through a gas hose.

The collector is a 200l barrel with water, and a bucket inverted in it to collect gas, as well as to create the pressure necessary for the operation of a gas furnace. As gas enters, the bucket will float. If the amount of biogas is greater than the plastic bucket can hold, then the gas will simply go out through the water.

For the manufacture of the reactor You will need a sealed barrel of 200 liters. We make several holes in the upper part of the barrel and install:
– plastic pipe for pouring raw materials. At the end of the pipe, it is necessary to install a transition to a large pipe (a kind of watering can, for the convenience of pouring raw materials)
– A plastic pipe for draining fertilizers. Because a biogas plant is not perpetual motion machine, and it is necessary to constantly make raw materials. When new raw materials are introduced, the surplus (already processed raw materials - fertilizers) will exit through the drain pipe.
– Tap at the highest point of the barrel for collecting biogas.

In the manufacture of the reactor, it is very important that all connections are tight, otherwise, under the pressure that has arisen, the gas may leak out. The drain pipe must be located below the installation level of the gas cock. The drain and fill pipes must be tightly plugged when not in use.

To make a collector, you will need a 200 l plastic barrel without a lid. Pour 3/4 of the water into the barrel and install another barrel, upside down, smaller in volume. In the bottom of the barrel of a smaller volume, we cut a fitting for connecting a hose from the reactor, and a tap for connecting a hose going to a gas furnace.

To fill the raw materials, open the inlet and outlet and fill in the raw materials. It is best to use manure diluted in water. It is best to use rainwater or settled water so that the chlorine content from the water supply does not reduce bacteria colonies. Also, if you are using kitchen waste, keep detergents, eggshell, bones, onion scales, as they can affect the operation of the biogas plant for the worse.

Biogas itself has a very unpleasant smell, but there is no smell when burning. If you burn gas without mixing with air, you will get a yellow flame with soot, which will easily smoke the bottom of the pan.

If biogas is mixed with air and then ignited, we get a pure blue flame without soot. So, for example, in factory gas stoves, the instructions say that when switching from main gas to bottled gas and vice versa, it is necessary to change jets (which differ in hole diameter), otherwise the burner will smoke. Alternatively, you can use laboratory bunsen burner.

If you do not have a laboratory burner available, then it is easy to make it from a piece of pipe by drilling holes at the base. Thus, the gas passing through the pipe will mix with air, and at the outlet of the pipe we will get a mixed gas.

As jets, you can experiment with pieces of wood by sharpening them under a pencil and drilling holes of different diameters in them. In this way, the optimal flame size can be obtained.

For the experiment, an old barbecue was used as a stove, in the bottom of which a hole was cut and a Bunsen burner was installed. And later, the barbecue was replaced with a single-burner stove.

To create gas pressure, a weight is placed on the collector (a small barrel for collecting gas). For example, if you install a load of 5 kg, then 1 liter of water can be boiled in 15 minutes. If you install a load of 10 kg, then 1 liter of water will boil in 10 minutes.

Summing up, it should be noted that homemade biogas plant produces biogas for 30 minutes of burner operation per day, if the raw material is manure. If, however, kitchen leftovers are used as raw materials, then the productivity is only 15 minutes per day.

The emitted gas is not so much, but you must admit that the biogas plant is not so big either. Therefore, if you want to increase the amount of gas produced, you will need to increase the reactor and collector volumes.

The dimensions of the collector may not be increased if you pump the biogas into another container (for example, into a cylinder) in a timely manner. Most simply, this can be done with a compressor from a refrigerator, which has one inlet and one outlet. We connect the input to the collector, and the output to the cylinder.

The compressor can be equipped with automation, for example, when the collector is filled with gas, the barrel rises, closes the contacts, thereby turning on the compressor. And the compressor, in turn, turned off when the barrel dropped to the minimum level.

Biogas plant reactor must be made of plastic, but, in no case from metal, because due to oxidative processes, the metal will quickly rust. Alternatively, you can use plastic barrels of large volumes (for example, eurocube). And so that large volumes of barrels do not take up much space in the yard, they can be buried.

Nov 19, 2016 Gennady