Biogas plant: recycling organic waste for good. How to get biogas at home Make gas from manure

The topic of alternative fuels has been relevant for several decades. Biogas is a natural source of fuel that you can generate and use on your own, especially if you have livestock.

What it is

The composition of biogas is similar to that produced on an industrial scale. Stages of biogas production:

1. A bioreactor is a container in which the biological mass is processed by anaerobic bacteria in a vacuum.
2. After some time, a gas is released, consisting of methane, carbon dioxide, hydrogen sulfide and other gaseous substances.
3. This gas is purified and removed from the reactor.
4. Processed biomass is an excellent fertilizer that is removed from the reactor to enrich the fields.

Do-it-yourself biogas production at home is possible, provided that you live in a village and you have access to animal waste. It is a good fuel option for livestock farms and agricultural businesses.

The advantage of biogas is that it reduces methane emissions and provides a source of alternative energy. As a result of biomass processing, fertilizer is formed for vegetable gardens and fields, which is an additional advantage.

To make your own biogas, you need to build a bioreactor to process manure, bird droppings, and other organic waste. As raw materials are used:

• wastewater;
• straw;
• grass;
• river silt.

It is important to prevent chemical impurities from entering the reactor, as they interfere with the reprocessing process.

Use cases

The processing of manure into biogas makes it possible to obtain electrical, thermal and mechanical energy. This fuel is used on an industrial scale or in private homes. It is used for:

• heating;
• lighting;
• water heating;
• operation of internal combustion engines.

With the help of a bioreactor, you can create your own energy base to provide a private home or agricultural production.

Biogas thermal power plants are an alternative way to heat a personal subsidiary farm or a small village. Organic waste can be converted into electricity, which is much cheaper than taking it to the site and paying utility bills. Biogas can be used for cooking on gas stoves. The great advantage of biofuels is that it is an inexhaustible, renewable source of energy.

Biofuel efficiency

Biogas from litter and manure is colorless and odorless. It gives as much heat as natural gas. One cubic meter of biogas provides as much energy as 1.5 kg of coal.

Most often, farms do not dispose of waste from livestock, but store it in one area. As a result, methane is released into the atmosphere, manure loses its properties as a fertilizer. Timely processed waste will bring much more benefits to the farm.

Calculating the efficiency of manure disposal in this way is easy. The average cow gives 30-40 kg of manure per day. From this mass, 1.5 cubic meters of gas is obtained. From this amount, electricity is generated 3 kW / h.

How to build a biomaterial reactor

Bioreactors are containers made of concrete with holes for the removal of raw materials. Before construction, you need to choose a place on the site. The size of the reactor depends on the amount of biomass you have daily. It should fill the container by 2/3.

If there is little biomass, instead of a concrete container, you can take an iron, for example, an ordinary barrel. But it must be strong, with high-quality welds.

The amount of gas produced directly depends on the volume of raw materials. In a small container, it will turn out a little. To get 100 cubic meters of biogas, you need to process a ton of biological mass.

To increase the strength of the installation, it is usually buried in the ground. The reactor must have an inlet pipe for loading biomass and an outlet for removing spent material. There must be a hole in the top of the tank through which the biogas is discharged. It is better to close it with a water seal.

For a correct reaction, the container must be hermetically sealed, without air access. The water seal will ensure the timely removal of gases, which will prevent the explosion of the system.

Reactor for a large farm

A simple bioreactor scheme is suitable for small farms with 1-2 animals. If you own a farm, it is best to install an industrial reactor that can handle large amounts of fuel. It is best to involve special firms involved in the development of the project and installation of the system.

Industrial complexes consist of:

• Intermediate storage tanks;
• mixer plant;
• A small CHP plant that provides energy for heating buildings and greenhouses, as well as electricity;
• Tanks for fermented manure used as fertilizer.

The most effective option is the construction of one complex for several neighboring farms. The more biomaterial is processed, the more energy is obtained as a result.

Before receiving biogas, industrial installations must be coordinated with the sanitary and epidemiological station, fire and gas inspection. They are documented, there are special rules for the location of all elements.

How to calculate the reactor volume

The volume of the reactor depends on the amount of waste generated daily. Remember that the container only needs to be filled 2/3 for efficient fermentation. Also consider fermentation time, temperature and type of raw materials.

Manure is best diluted with water before being sent to the reactor. It will take about 2 weeks to process manure at a temperature of 35-40 degrees. To calculate the volume, determine the initial volume of waste with water and add 25-30%. The volume of biomass should be the same every two weeks.

How to ensure biomass activity

For proper biomass fermentation, it is best to heat the mixture. In the southern regions, the air temperature contributes to the start of fermentation. If you live in the north or in the middle lane, you can connect additional heating elements.

To start the process, a temperature of 38 degrees is needed. There are several ways to provide it:

• Coil under the reactor, connected to the heating system;
• Heating elements inside the tank;
• Direct heating of the tank with electric heaters.

The biological mass already contains bacteria that are needed to produce biogas. They wake up and begin activity when the air temperature rises.

It is best to heat them with automatic heating systems. They turn on when cold mass enters the reactor and turn off automatically when the temperature reaches the desired value. Such systems are installed in water-heating boilers, they can be bought at gas equipment stores.

If you provide heating to 30-40 degrees, then it will take 12-30 days to process. It depends on the composition and volume of the mass. When heated to 50 degrees, bacterial activity increases, and processing takes 3-7 days. The disadvantage of such installations is the high cost of maintaining a high temperature. They are comparable to the amount of fuel received, so the system becomes inefficient.

Another way to activate anaerobic bacteria is biomass mixing. You can independently install the shafts in the boiler and bring the handle out to stir the mass if necessary. But it is much more convenient to design an automatic system that will mix the mass without your participation.

Proper gas venting

Biogas from manure is removed through the top cover of the reactor. During fermentation, it must be tightly closed. Usually a water seal is used. It controls the pressure in the system, with an increase in the cover rises, the release valve is activated. A weight is used as a counterweight. At the outlet, the gas is cleaned with water and flows further through the pipes. Purification with water is necessary to remove water vapor from the gas, otherwise it will not burn.

Before biogas can be converted into energy, it must be stored. It should be stored in a gas holder:

• It is made in the form of a dome and installed at the outlet of the reactor.
• Most often it is made of iron and covered with several layers of paint to prevent corrosion.
• In industrial complexes, the gas tank is a separate tank.

Another option for making a gas tank is to use a PVC bag. This elastic material stretches as the bag fills up. If necessary, it can store a large amount of biogas.

Underground Biofuel Plant

To save space, it is best to build underground installations. This is the easiest way to get biogas at home. To equip an underground bioreactor, you need to dig a hole and fill its walls and bottom with reinforced concrete.

On both sides of the container, holes are made for the inlet and outlet pipes. Moreover, the outlet pipe should be located at the base of the container for pumping out the waste mass. Its diameter is 7-10 cm. An inlet with a diameter of 25-30 cm is best located in the upper part.

From above, the installation is closed with brickwork and a gas holder is installed to receive biogas. At the outlet of the tank, you need to make a valve to regulate the pressure.

The biogas plant can be buried in the yard of a private house and connected to sewage and livestock waste. Processing reactors can fully cover the needs of the family in electricity and heating. An additional plus in obtaining fertilizer for the garden.

A do-it-yourself bioreactor is a way to get energy from pasture material and make money from manure. It reduces farm energy costs and increases profitability. You can make it yourself or have it installed. The price for it depends on the volume, starts from 7000 rubles.

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

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

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

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

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

Here are my arguments and facts:

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

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

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

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

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

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

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

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

But manure needs to be recycled!

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

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

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

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

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

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

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