Biogas is a gas produced by the fermentation of biomass. IN natural conditions Biogas is constantly being generated. In modern bioenergy, the natural processes of its formation are brought under human control. Biogas production is carried out at biogas stations using special installations. The produced biogas consists of methane (more than 50%) and carbon dioxide, as well as a small amount of impurities (hydrogen and hydrogen sulfide). After purifying biogas from C0 2 (biogas upgrading), biomethane is obtained - a complete analogue of natural gas.
Unlike solar and wind, biogas can, like natural gas, be stored and provide continuous electricity production, i.e., perform an important task of energy supply during periods of peak load on the electrical grid.
Biogas can be used for electricity and heat generation, refueling cars (in large cities in Sweden, the municipal bus fleet is refueled with local biogas), and can be injected (after conversion into biomethane) into existing gas networks and storage facilities.
Why do we need biogas if we have natural gas and the infrastructure for its delivery?
Firstly, biogas is made from biomass, a renewable plant material - its production and use leaves a smaller carbon footprint.
Secondly, biogas production can (and should) use agricultural waste, which prevents pollution environment and increases its efficiency.
The European biogas industry has experienced double-digit growth in recent years. Electricity production from biogas in the EU amounted to 46,419 GWh in 2012, in 2013 - 52,327 GWh (for comparison: this amount of energy approximately corresponds to the annual electricity consumption of Portugal). More than half of European production came from Germany 111 , which has 8,700 biogas plants 112 .
China is considered the world leader in biogas production, 113 but an interesting phenomenon is observed here. The vast majority of Chinese biogas is produced by rural households for their own consumption - heating, cooking and even, in some cases, electricity generation. There are 41 million 114 such home biogas plants, and the number is expected to reach 80 million by 2020 with active government support.
In the production of biogas, the most desirable from an environmental point of view is the use of animal and poultry waste. These industries generate large volumes of liquid and solid waste, the disposal of which must be preceded by particularly careful treatment. In countries with weak environmental control, which includes Russia, livestock waste can poison the soil and water bodies. Using this waste to produce biogas and then generate heat and electricity is actually a win-win strategy. On the one hand, the problem of environmental pollution is largely eliminated, on the other hand, farms and their environment are provided with “free” energy.
However, this sensible approach to biogas energy faces, so to speak, economic reality. The fact is that producing biogas from animal waste is more expensive than from specially grown “energy plants”; more complex processing of the feedstock is required with corresponding additional capital costs.
Germany faced this economic reality harshly. Ill-conceived policy to stimulate the biogas business contributed to the non-recycling of waste Agriculture, and the orientation of bioenergy towards the intensive cultivation of energy plants (primarily corn) on agricultural lands for the subsequent production of electricity has led to the massive construction of biogas power plants even in environmental zones 115 . The area under maize used for bioenergy has doubled over the past decade, largely at the expense of other crops 116 .
In 2014, German biogas policy underwent a major adjustment. came into force on August 1 new edition The Renewable Energy Act (EEG), which requires further development of biogas energy to be based on waste recycling rather than the use of specially grown energy crops. The tightening was also reflected in the reduction of feed-in tariffs and financial measures limiting the construction of large biogas power plants. Similar measures are currently being considered throughout the European Union.
Thus, further fate The biogas industry in Europe looks largely uncertain. We can assume with a fair degree of confidence that there will be no reduction in existing capacities, but the pace of further expansion is difficult to predict. However, no one has yet canceled the existing official European expansion plans (National Renewable Energy Actions Plans). They provide for the volume of biogas electricity generation by 2020 at the level of 65,000 GWh (average annual increase of 1.85 GWh) 117 . To produce this amount of energy, 28 million cubic meters of biogas (natural gas equivalent) are needed, which is 5% of European natural gas consumption.
It should also be taken into account that such large economies with developed agriculture as France and Spain today have an extremely low degree of penetration of the biogas business. Thus, according to the results of 2013, France is inferior in biogas production to Italy by four times, and Germany by more than 14 times. This is a factor that increases the likelihood of achieving stated growth goals.
Biogas is an excellent alternative to standard heating oils. The article contains information about the history of the use of biogas and recommendations for creating your own biogas plant.
Among the important components of our life great importance have energy resources whose prices are rising almost every month. Every winter season makes a hole in family budgets, forcing them to bear heating costs, and therefore, fuel for heating boilers and furnaces.
But what should we do, because electricity, gas, coal or firewood cost money, and the more remote our homes are from major energy highways, the more expensive their heating will be. Meanwhile, alternative heating, independent of any suppliers and tariffs, can be built on biogas, the production of which does not require geological exploration, well drilling, or expensive pumping equipment.
Biogas can be obtained practically at home, while incurring minimal, quickly recouped costs - you will find a lot of information on this issue in our article.
Heating with biogas
Story
Interest in flammable gas formed in swamps during the warm season of the year arose among our distant ancestors - advanced cultures of India, China, Persia and Assyria experimented with biogas over 3 thousand years ago.
In the same ancient times, in tribal Europe, the Alemanni Swabians noticed that the gas released in the swamps burned well - they used it to heat their huts, supplying gas to them through leather pipes and burning them in the hearths. The Swabians considered biogas to be the “breath of dragons,” which they believed lived in swamps.
Centuries and millennia later, biogas experienced its second discovery - in the 17th and 18th centuries, two European scientists immediately paid attention to it.
The famous chemist of his time, Jan Baptista van Helmont, established that during the decomposition of any biomass, flammable gas, and the renowned physicist and chemist Alessandro Volta established a direct relationship between the amount of biomass in which decomposition processes take place and the amount of biogas released.
In 1804, the English chemist John Dalton discovered the formula for methane, and four years later the Englishman Humphry Davy discovered it as part of swamp gas.
Left: Jan Baptista van Helmont. Right: Alessandro Volta
Interest in the practical use of biogas arose with the development of gas street lighting - at the end of the 19th century, the streets of one district of the English city of Exeter were illuminated with gas obtained from a sewage collector.
Methane formula
In the 20th century, energy demands caused by World War II forced Europeans to look for alternative energy sources. Biogas plants, in which gas was produced from manure, spread in Germany and France, and partly in Eastern Europe.
However, after the victory of the countries of the anti-Hitler coalition, biogas was forgotten - electricity, natural gas and petroleum products completely covered the needs of industries and the population.
In the USSR, the technology for producing biogas was considered mainly from an academic point of view and was not considered to be in any demand.
Today the attitude towards alternative sources energy has changed dramatically - they have become interesting, since the cost of conventional energy resources is increasing year by year.
At its core, biogas is a real way to avoid tariffs and costs for classical energy sources, to obtain your own source of fuel, for any purpose and in sufficient quantities.
The largest number of biogas plants have been created and operated in China: 40 million medium- and low power, the volume of methane produced is about 27 billion m3 per year.
Biogas - what is it
This is a gas mixture consisting mainly of methane (content from 50 to 85%), carbon dioxide (content from 15 to 50%) and other gases in much smaller percentages. Biogas is produced by a team of three types of bacteria that feed on biomass - hydrolysis bacteria, which produce food for acid-forming bacteria, which in turn provide food for methane-producing bacteria, which form biogas.
Chemical composition of biogas
Fermentation of the original organic material(for example, manure), the product of which will be biogas, passes without access to the external atmosphere and is called anaerobic.
Another product of such fermentation, called compost humus, is well known to rural residents, who use it to fertilize fields and vegetable gardens, but those produced in compost heaps biogas and thermal energy are usually not used - and in vain!
What factors determine the yield of biogas with a higher methane content?
First of all, it depends on the temperature. The higher the temperature of their environment, the higher the activity of bacteria fermenting organic matter. sub-zero temperatures Fermentation slows down or stops completely.
For this reason, biogas production is most common in countries in Africa and Asia, located in the subtropics and tropics. In the Russian climate, obtaining biogas and completely switching to it as an alternative fuel will require thermal insulation of the bioreactor and the introduction warm water into the mass of organic matter when the temperature of the external atmosphere drops below zero.
Organic material placed in a bioreactor must be biologically degradable; a significant amount of water must be introduced into it - up to 90% of the mass of organic matter. An important point there will be a neutrality of the organic environment, the absence in its composition of components that prevent the development of bacteria, such as cleaning and detergents, and any antibiotics.
Biogas can be obtained from almost any waste of economic and plant origin, Wastewater, manure, etc.
The process of anaerobic fermentation of organic matter works best when the pH value is in the range of 6.8–8.0 - high acidity will slow down the formation of biogas, because bacteria will be busy consuming acids and producing carbon dioxide, which neutralizes the acidity.
The ratio of nitrogen and carbon in the bioreactor must be calculated as 1 to 30 - in this case, the bacteria will receive the amount of carbon dioxide they need, and the methane content in the biogas will be the highest.
The best yield of biogas with a sufficiently high methane content is achieved if the temperature in the fermentable organic matter is in the range of 32–35 ° C, with lower and higher values in biogasthe carbon dioxide content increases, its quality decreases.
Bacteria that produce methane are divided into three groups: psychrophilic, effective at temperatures from +5 to +20 ° C; mesophilic, their temperature range is from +30 to +42 °C; thermophilic, operating in the mode from +54 to +56 °C. For the biogas consumer, mesophilic and thermophilic bacteria, which ferment organic matter with a higher gas yield, are of greatest interest.
Mesophilic fermentation is less sensitive to changes in temperature by a couple of degrees from the optimal temperature range and requires less energy to heat organic material in the bioreactor.
Its disadvantages, compared to thermophilic fermentation, are lower gas yield, longer period of complete processing of the organic substrate (about 25 days), the resulting decomposed organic material may contain harmful flora, since the low temperature in the bioreactor does not ensure 100% sterility.
Raising and maintaining the intra-reactor temperature at a level acceptable for thermophilic bacteria will ensure the greatest yield of biogas, complete fermentation of organic matter will take place in 12 days, the decomposition products of the organic substrate are completely sterile.
Negative characteristics: going beyond the temperature range acceptable for thermophilic bacteria by 2 degrees will reduce the gas yield; high need for heating, as a result - significant energy costs.
The contents of the bioreactor must be stirred twice a day, otherwise a crust will form on its surface, creating a barrier to biogas. In addition to eliminating it, stirring allows you to equalize the temperature and acidity level inside the organic mass.
In continuous cycle bioreactors, the highest biogas yield occurs with the simultaneous unloading of organic matter that has undergone fermentation and the loading of new organic matter in an amount equal to the unloaded volume.
In small bioreactors, which are usually used in dacha farms, every day it is necessary to extract and add organic matter in a volume approximately equal to 5% of the internal volume of the fermentation chamber.
The yield of biogas directly depends on the type of organic substrate placed in the bioreactor (the average data per kg of dry substrate weight is given below):
- horse manure produces 0.27 m3 of biogas, methane content 57%;
- cattle manure produces 0.3 m3 of biogas, methane content 65%;
- fresh cattle manure produces 0.05 m3 of biogas with 68% methane content;
- chicken droppings- 0.5 m3, the methane content in it will be 60%;
- pig manure- 0.57 m3, the share of methane will be 70%;
- sheep manure - 0.6 m3 with a methane content of 70%;
- wheat straw - 0.27 m3, with 58% methane content;
- corn straw - 0.45 m3, methane content 58%;
- grass - 0.55 m3, with 70% methane content;
- wood foliage - 0.27 m3, methane share 58%;
- fat - 1.3 m3, methane content 88%.
Biogas plants
These devices consist of the following main elements - a reactor, an organic loading hopper, a biogas outlet, and a fermented organic matter unloading hopper.
According to the type of design, biogas plants are of the following types:
- without heating and without stirring the fermented organic matter in the reactor;
- without heating, but with stirring of the organic mass;
- with heating and stirring;
- with heating, stirring and devices that allow you to control and manage the fermentation process.
The first type of biogas plant is suitable for a small farm and is designed for psychrophilic bacteria: the internal volume of the bioreactor is 1–10 m3 (processing 50–200 kg of manure per day), minimal equipment, the resulting biogas is not stored - it immediately goes to the household appliances that consume it.
This installation can only be used in southern regions; it is designed for an internal temperature of 5–20 °C. Removal of fermented organic matter is carried out simultaneously with the loading of a new batch; the shipment is carried out into a container, the volume of which must be equal to or greater than the internal volume of the bioreactor. The contents of the container are stored in it until introduced into the fertilized soil.
The design of the second type is also designed for small farms, its productivity is slightly higher than the biogas plants of the first type - the equipment includes a mixing device with a manual or mechanical drive.
The third type of biogas plants is equipped, in addition to the mixing device, with forced heating of the bioreactor; the hot water boiler runs on alternative fuel produced by the biogas plant. Methane production in such installations is carried out by mesophilic and thermophilic bacteria, depending on the heating intensity and temperature level in the reactor.
Schematic diagram of a biogas plant: 1 - substrate heating; 2 - filler neck; 3 - bioreactor capacity; 4 - hand mixer; 5 - container for collecting condensate; 6 - gas valve; 7 - tank for processed mass; 8 - safety valve; 9 - filter; 10 - gas boiler; 11 - gas valve; 12 - gas consumers; 13 - water seal
The last type of biogas plants is the most complex and is designed for several consumers of biogas; the design of the plants includes an electric contact pressure gauge, a safety valve, a hot water boiler, a compressor (pneumatic mixing of organic matter), a receiver, a gas tank, a gas reducer, and an outlet for loading biogas into transport. These installations operate continuously, allow the setting of any of three temperature conditions thanks to precisely adjustable heating, and biogas selection is carried out automatically.
DIY biogas plant
The calorific value of biogas produced in biogas plants is approximately 5,500 kcal/m3, which is slightly lower than the calorific value of natural gas (7,000 kcal/m3). For heating 50 m2 of residential building and use gas stove with four burners an average of 4 m3 of biogas is required per hour.
Industrial biogas production plants offered on the Russian market cost from 200,000 rubles. - despite their apparently high cost, it is worth noting that these installations are precisely calculated according to the volume of loaded organic substrate and are covered by manufacturer’s warranties.
If you want to create a biogas plant yourself, then further information is for you!
Bioreactor form
The best shape for it would be oval (egg-shaped), but building such a reactor is extremely difficult. A cylindrical bioreactor, the upper and lower parts of which are made in the form of a cone or semicircle, will be easier to design.
Square or rectangular reactors made of brick or concrete will be ineffective, because cracks will form in the corners over time caused by the pressure of the substrate, and hardened organic fragments will also accumulate in them, interfering with the fermentation process.
Steel bioreactor tanks are airtight, resistant to high pressure, and are not that difficult to build. Their disadvantage is that they are weakly resistant to rust and require application to the internal walls. protective coating, for example, resins. The outside of the steel bioreactor must be thoroughly cleaned and painted in two layers.
Bioreactor containers made of concrete, brick or stone must be carefully coated on the inside with a layer of resin that can ensure their effective water and gas impermeability, withstand temperatures of about 60 ° C, and the aggression of hydrogen sulfide and organic acids.
In addition to resin, to protect the internal surfaces of the reactor, you can use paraffin, diluted with 4% motor oil (new) or kerosene and heated to 120–150 ° C - the surfaces of the bioreactor must be heated with a burner before applying a paraffin layer to them.
When creating a bioreactor, you can use plastic containers that are not susceptible to rust, but only hard ones with sufficiently strong walls. Soft plastic can only be used in the warm season, because with the onset of cold weather it will be difficult to attach insulation to it, and its walls are not strong enough. Plastic bioreactors can only be used for psychrophilic fermentation of organic matter.
Bioreactor location
Its placement is planned depending on free space on the site, distance from residential buildings, location of waste and animals, etc. Planning a ground-based, fully or partially submerged bioreactor depends on the level groundwater, convenience of input and output of the organic substrate into the reactor tank.
It would be optimal to place the reactor vessel below ground level - savings are achieved on equipment for introducing an organic substrate, thermal insulation is significantly increased, for which you can use inexpensive materials(straw, clay).
Bioreactor equipment
The reactor tank must be equipped with a hatch, which can be used to carry out repair and maintenance work. It is necessary to lay a rubber gasket or a layer of sealant between the bioreactor body and the hatch cover. It is optional, but extremely convenient, to equip the bioreactor with a temperature sensor, internal pressure and the level of organic substrate.
Bioreactor thermal insulation
Its absence will not allow the operation of the biogas plant all year round, only in warm weather. To insulate a buried or semi-buried bioreactor, clay, straw, dry manure and slag are used. The insulation is laid in layers - when installing a buried reactor, the pit is covered with a layer of PVC film that prevents direct contact thermal insulation material with soil.
Before installing the bioreactor, straw is poured onto the bottom of the pit, a layer of clay is placed on top of it, then the bioreactor is placed. After this, all free areas between the reactor tank and the pit lined with PVC film are filled with straw almost to the end of the tank, and a 300 mm layer of clay mixed with slag is poured on top.
The diameter of the pipes for loading into and unloading from the bioreactor must be at least 300 mm, otherwise they will clog. In order to maintain anaerobic conditions inside the reactor, each of them should be equipped with screw or half-turn valves. The volume of the bunker for supplying organic matter, depending on the type of biogas plant, should be equal to the daily volume of input raw materials.
The feed hopper should be positioned on sunny side bioreactor, since this will increase the temperature in the introduced organic substrate, accelerating the fermentation processes. If the biogas plant is connected directly to the farm, then the bunker should be placed under its structure so that the organic substrate enters it under the influence of gravity.
The pipelines for loading and unloading the organic substrate should be located on opposite sides of the bioreactor - in this case, the input raw materials will be distributed evenly, and the fermented organic matter will be easily removed under the influence of gravitational forces and the mass of the fresh substrate.
Holes and installation of the pipeline for loading and unloading organic matter should be completed before installing the bioreactor at the installation site and before placing layers of thermal insulation on it. The tightness of the internal volume of the bioreactor is achieved by the fact that the pipe entries are located at an acute angle, while the liquid level inside the reactor is higher than the pipe entry points - a hydraulic seal blocks the access of air.
The easiest way to introduce new and remove fermented organic material is by the overflow principle, i.e., raising the level of organic matter inside the reactor when introducing a new portion will remove the substrate through the unloading pipe in a volume equal to the volume of the introduced material.
If fast loading of organic matter is necessary, and the efficiency of introducing material by gravity is low due to imperfections in the relief, installation of pumps will be required. There are two methods: dry, in which the pump is installed inside the loading pipe and the organic material enters the pump through vertical pipe, pumped by it; wet, in which the pump is installed in the loading hopper, its drive is carried out by a motor, also installed in the hopper (in an impenetrable housing) or through a shaft, while the motor is installed outside the hopper.
How to collect biogas
This system includes gas pipeline, distributing gas to consumers, shut-off valves, condensate collection tanks, safety valve, receiver, compressor, gas filter, gas holder and gas consumption devices. Installation of the system is carried out only after the bioreactor is completely installed at its location.
The outlet for collecting biogas is located at the highest point of the reactor; the following are connected in series to it: a sealed container for collecting condensate; safety valve and water seal - a container with water, the gas pipeline entry into which is made below the water level, the outlet - above (the gas pipeline pipe in front of the water seal should be bent so that water does not penetrate into the reactor), which will not allow gas to move in the opposite direction.
Biogas formed during the fermentation of an organic substrate contains a significant amount of water vapor, which forms condensate along the walls of the gas pipeline and, in some cases, blocks the flow of gas to consumers.
Since it is difficult to build a gas pipeline in such a way that there is a slope along its entire length towards the reactor, where condensate would flow, it is necessary to install water seals in the form of containers with water in each of its low sections. During operation of a biogas plant, it is periodically necessary to remove some of the water from them, otherwise its level will completely block the flow of gas.
The gas pipeline must be built with pipes of the same diameter and the same type, all valves and elements of the system must also have the same diameter. Steel pipes with a diameter of 12 to 18 mm are applicable for biogas plants of low and medium power, the flow rate of biogas supplied through pipes of these diameters should not exceed 1 m3/h (at a flow rate of 0.5 m3/h, the use of pipes with a diameter of 12 mm per length is not allowed over 60 m).
The same condition applies when used in a gas pipeline. plastic pipes, in addition, these pipes must be laid 250 mm below ground level, since their plastic is sensitive to sunlight and loses under the influence solar radiation strength.
When laying a gas pipeline, it is necessary to carefully ensure that there are no leaks and that the joints are gas-tight - the check is carried out with a soap solution.
Gas filter
Biogas contains a small amount of hydrogen sulfide, the combination of which with water creates an acid that actively corrodes the metal - for this reason, unfiltered biogas cannot be used for engines internal combustion. Meanwhile, hydrogen sulfide can be removed from gas using a simple filter - a 300 mm piece gas pipe filled with a dry mixture of metal and wood shavings.
After every 2,000 m3 of biogas passed through such a filter, it is necessary to extract its contents and keep it in open air for about an hour - the shavings will be completely cleared of sulfur and can be reused.
Shut-off fittings and valves
A main gas valve is installed in the immediate vicinity of the bioreactor; a valve should be inserted into the gas pipeline to release biogas at a pressure of more than 0.5 kg/cm2. The best valves for a gas system are chrome-plated ball valves; you cannot use valves designed for plumbing systems in a gas system. The installation of a ball valve on each gas consumer is mandatory.
Mechanical stirring
For small-volume bioreactors, stirrers with manual drive fit best - they are simple in design and do not require any special conditions during operation. A mechanically driven mixer is designed like this - a horizontal or vertical shaft placed inside the reactor along its central axis, with blades attached to it, which, when rotated, move masses of organic matter rich in bacteria from the area where the fermented substrate is unloaded to the place where a fresh portion is loaded.
Be careful - the mixer should rotate only in the direction of mixing from the unloading area to the loading area; the movement of methane-producing bacteria from the mature substrate to the newly received one will accelerate the maturation of organic matter and the production of biogas with a high methane content.
How often should the organic substrate be mixed in the bioreactor? It is necessary to determine the frequency by observation, focusing on the yield of biogas - excessively frequent stirring will disrupt fermentation, since it will interfere with the activity of bacteria, in addition, it will cause the release of unprocessed organic matter. On average, the time interval between stirrings should be from 4 to 6 hours.
Heating of organic substrate in a bioreactor
Without heating, the reactor can only produce biogas in psychrophilic mode, resulting in less gas produced and poorer fertilizer quality than in higher temperature mesophilic and thermophilic operating modes.
The substrate can be heated in two ways: steam heating; combination of organic matter with hot water or heating using a heat exchanger in which circulates hot water(not mixed with organic material).
A serious disadvantage of steam heating (direct heating) is the need to include a steam generation system in the biogas plant, which includes a system for purifying water from the salt present in it.
A steam generation plant is only beneficial for truly large installations that process large volumes of substrate, for example, wastewater. In addition, heating with steam will not allow you to accurately control the heating temperature of organic matter; as a result, it may overheat.
Heat exchangers located inside or outside the bioreactor plant indirectly heat the organic matter inside the reactor. You should immediately discard the option of heating through the floor (foundation), since the accumulation of solid sediment at the bottom of the bioreactor prevents it. The best option would be to insert a heat exchanger inside the reactor, but the material that forms it must be strong enough and successfully withstand the pressure of organic matter when mixing it.
Heat exchanger larger area It will heat organic matter better and more uniformly, thereby improving the fermentation process. External heating, while less efficient due to heat loss from the walls, is attractive because nothing inside the bioreactor will interfere with the movement of the substrate.
The optimal temperature in the heat exchanger should be about 60 °C; the heat exchangers themselves are made in the form of radiator sections, coils, and parallel welded pipes. Maintaining the coolant temperature at 60 °C will reduce the threat of suspended particles sticking to the walls of the heat exchanger, the accumulation of which will significantly reduce heat transfer. The optimal location for the heat exchanger is near the mixing blades; in this case, the threat of sedimentation of organic particles on its surface is minimal.
The heating pipeline of the bioreactor is designed and equipped similarly to a conventional heating system, i.e., the conditions for returning cooled water to the lowest point of the system must be met, and air release valves are required at its highest points. The temperature of the organic mass inside the bioreactor is controlled by a thermometer, which the reactor should be equipped with.
Gas tanks for collecting biogas
With constant gas consumption, there is no need for them, unless they can be used to equalize the gas pressure, which will significantly improve the combustion process. For low-capacity bioreactor plants, large-volume automobile chambers that can be connected in parallel are suitable as gas holders.
More serious gas tanks, steel or plastic, are selected for a specific bioreactor installation - in the best option The gas tank must accommodate the volume of biogas produced daily. The required capacity of a gas tank depends on its type and the pressure for which it is designed; as a rule, its volume is 1/5...1/3 of the internal volume of the bioreactor.
Steel gas tank. There are three types of steel gas tanks: low pressure, from 0.01 to 0.05 kg/cm2; average, from 8 to 10 kg/cm2; high, up to 200 kg/cm2. It is not practical to use low-pressure steel gas tanks; it is better to replace them with plastic gas tanks - they are expensive and are only applicable if there is a significant distance between the biogas plant and consumer devices.
Low pressure gas tanks are used mainly to equalize the difference between the daily biogas output and its actual consumption.
Biogas is pumped into medium- and high-pressure steel gas tanks by a compressor; they are used only in medium- and large-capacity bioreactors.
Gas tanks must be equipped with the following control and measuring devices: safety valve, water seal, pressure reducer and pressure gauge. Steel gas tanks must be grounded!published
If you have any questions on this topic, ask them to the experts and readers of our project.
Among industrialized countries, Denmark takes the leading place in the production and use of biogas. Biogas produced in this country accounts for up to 18% of its total energy balance. In absolute terms, Germany occupies the leading place in the number of medium and large installations (about 10,000).
In Italy currently not state program development of biogas plants, but the Italian electricity company is obliged to buy electricity generated from biogas at a price 80% higher than the price for consumers. In Austria, until 1997, there were 46 predominantly farm-type biogas plants in operation. In 1997, 10 farm-type installations and 5 large ones were put into operation. It is planned to increase the number of biogas plants to 150. In Austria there is no national program to support the construction of biogas plants, but their construction is supported by the Ministries of Agriculture and the Environment. Financial support is provided by federal agricultural organizations and banks.
In the northern regions, in order to save fuel, biogas plants use mesophilic mode, which increases the retention time and working volume of the reactors. An example is the design of biogas plants developed by AB Enbom (Finland), operating in Lapland conditions at temperature conditions fermentation 33°C.
The disadvantage of the European path to the development of biogas energy is the lack of a guaranteed supply of waste to generating facilities, enshrined at the legislative level. As a result, after an increase in the number of operating stations and the formation of a waste shortage, the costs of operating plants have sharply increased due to increased costs for purchasing waste or growing plant matter, as well as their delivery.
The vast majority of biogas stations accumulate unprocessed waste, which, on the one hand, worsens environmental situation, on the other hand, leads to increased costs for their storage and transportation. But in the European Union, amendments to the waste law have already begun to take effect, which oblige the owners of biogas stations to process the fermented mass into fertilizers
In India, Vietnam, Nepal and other countries, small (single-family) biogas plants are being built. The gas produced in them is used for cooking. In India, 3.8 million small biogas plants have been installed since 1981. Nepal has a program to support the development of biogas energy, thanks to which rural areas by the end of 2009, 200 thousand small biogas plants had been created.
China is currently the world leader in the implementation of biogas production technologies in rural regions. More than 40 million Chinese families have already installed biogas plants in their homes, and this figure is growing by several million per year. The total production of biogas is 10.2 billion m3/year, which puts China in first place in the world in terms of this indicator. In addition, 4,000 large biogas stations have been built in China, operating on the basis of waste from livestock farms, and the share of agricultural enterprises using biogas technologies is 52%
Chinese authorities are seriously counting on biogas as a significant source of electricity for rural areas. So, if by the end of the seven-year plan the total capacity of cogeneration installations will be 5.5 GW, then by 2030 it should increase to 30 GW, that is, 6 times, which will fully provide village residents with electricity and heat own production.
But Chinese installations have a significant disadvantage: the cost of the resulting product. The reactor volume of a Chinese installation is usually at least five cubic meters. Another aspect is the high cost of the installation itself. Costs are mainly spent on digging a pit and producing a large volume of cement works, install a metal dome-gas holder. Due to the fact that the iron dome of the gas tank is susceptible to corrosion, this equipment is designed to operate for only 8 to 10 years.
Conclusion
Modern waste processing technologies do not stand still and are becoming more and more efficient.
The biogas station solves the problem of organic waste disposal and wastewater treatment, thereby minimizing possible fines for environmental violations associated with the storage and removal of manure. The use of biogas not only provides a significant reduction in production costs, uninterrupted power and heat supply to one’s own production, but also the opportunity to receive additional profit from the sale of energy, heat and biofertilizers. The use of biofertilizers helps improve soil quality and increase crop yields. The result is environmentally friendly crop and livestock products and a reduction in overall pollution of the environment and arable land.
The social project Biobolsa provides local farmers with simple biogas plants that allow them to autonomously produce gas from organic waste. In 2010, the project started in Mexico, and today it is actively developing in 9 countries Latin America and Africa.
The idea for the Biobolsa project arose back in 2007, when a young Mexican, Alex Eaton, decided to make a low-cost anaerobic natural gas bioreactor for farms. By 2010, Alex had filed all the patents and fully launched the first pilot project. 
What is the Biobolsa bioreactor?
In principle, nothing complicated, large durable membrane bags 15 meters long, 2 meters wide and more than 2 meters high. Their capacity is about 40,000 liters of liquid, and the ability to process up to 1 ton of waste per day. There are more compact solutions 2x2 meters for small family, they process up to 20 kg of waste. 
With such a biogas plant, one peasant family with four pigs can produce enough biogas for cooking in the kitchen. 
Farmers often see a 20-40% increase in yield in the first year, and it only increases every year. On a farm with 1,000 pigs, the family is equipped with a system that can produce more energy than they can consume and they even sell the electricity back to the Mexican grid. 
The widespread introduction of such biogas plants also has a beneficial effect on the environment. According to research by the Food Organization FAO, modern agricultural businesses generate more greenhouse gas emissions than transport. This sector also pollutes water sources with animal waste, antibiotics, hormones, chemical fertilizers and pesticides used to grow crops. 
Biogas plants convert methane and carbon dioxide into energy, reducing greenhouse gases from agricultural activities, and the use organic fertilizers prevents pollution of watersheds. Farmers who have switched to biogas as a power source for their homes do not depend on fossil fuels and do not cut trees for fuel. This slows deforestation and improves air quality.
So biogas plants are a little more than just bags for rural families. Eaton argues that this approach also awakens emotional connection with the world around them, and farmers are starting to embrace the culture of reusing waste.
With the support of various foundations and government agencies, the creators of Biobolsa managed to secure partial subsidies for interested parties. And this was the impetus for the introduction of installations in the poorest and most depressed regions of Latin America. This year it is planned to launch 2 more pilot projects in Africa.
Biobolsa has received several international awards as a social entrepreneurship, among others, the business development network Network from Holland presented an award of 10,000 euros, which served as a powerful impetus for the development of the project.
“We estimate that in Mesquique alone there are 4 million homes that could potentially use biogas plants,” says Alex Eaton.
Based on materials:
Biogas plants from China are complexes that are designed to process various animal wastes, Food Industry, as well as organics. The work is based on the principle of fermentation of organic substances, which results in the formation of biogas, which includes methane, carbon dioxide, hydrogen sulfide, hydrogen and nitrogen.
Today, biogas is universal. It can be used for heating systems or as an integral part of a waste treatment and treatment system.
As you know, China is the only country in the world where biogas has been used for a very long time. Biogas plants from China were even exported at the end of the 19th century. More than half of public transport in China runs on biogas fuel. Naturally, the initial developments were classified, but already in 1999 there were approximately 7 million operating biogas plants in China.
The government's strategy in this area targets an increase in the production of biofuel installations by 15% annually. Today, thanks to many years of experience and modern technologies, Chinese-made biogas plants are successful not only in China, but also abroad. And other producing countries are adopting China’s experience. Also recently, the fact that biogas plants are made by ordinary people with their own hands has become increasingly popular.
Biogas plants from China for home or production
You can place an order directly from the manufacturer via the Internet. In online stores you can view biogas plants reviews from those who have already purchased similar plants for personal use. Also, price lists are often posted on the manufacturer’s website, in which you can view biogas installation prices.
