Recently, prices for electricity, energy carriers and other equipment are gradually increasing. This means that you have to pay more and more for the use of energy. In addition, in remote villages, towns, etc. and there may be problems with the supply of the resource. That is why biogas plants began to actively appear and be bought on the market. You can also assemble such a device with your own hands, and it is not as difficult as it might seem at first glance.
The basis of the installation is a bioreactor
A bioreactor is a container inside which anaerobic decomposition of biomass takes place. The reactor is called a fermenter or a methane tank.
Today, there are several main types of such structures. These include fully sealed reactors with a fixed or floating dome and reactorsdesigns resembling an ordinary diving bell.
Brief description of bell type
Designing a bell psychrophilic biogas plant with your own hands is quite a doable task. The bioreactor of this type of installation is open, inside there is a liquid biomass, into which a container is immersed, having the form of a cylinder or a bell. It collects the biogas released during decomposition. The substance accumulating under the cylinder will exert pressure on it, the bell will rise, playing the role of a small gas holder - a device for temporary storage of gas.
Naturally, among the main design flaws, the following should be noted: there is no way to mix the substrate. In addition, in the cold season it will not be possible to heat it to the desired decomposition temperature. Such reactors emit an unpleasant odor, and due to the fact that there is no cover, a stalemate arises altogether. Plus, the absence of a sealed cover leads to the fact that the installation emits part of the gases into the atmosphere, thereby polluting it. For these reasons, do-it-yourself bell-type biogas plants are usually assembled either for artisanal production of plants or in countries where the weather is constantly hot.
Dome Fermenter
Fixed-dome bioreactors are used in order to get rid of major disadvantages and minimize air pollution. It is these models that are most often used when mounting onindustrial facilities or in areas of private houses. By the way, it is worth noting that assembling a biogas plant for the home has recently become quite popular.
It is worth noting that the shape of the dome does not affect the process of gas formation itself, but if it is made in the form of a cylinder with a domed roof, it will be possible to achieve maximum savings in building materials. There is one big BUT: since the reactor is completely closed, it must be equipped with nozzles through which a new substrate will be loaded and the old one will be cleaned.
Installation types
Since do-it-yourself installation for a home biogas plant with a closed dome is most suitable, let's take a closer look at its simple design. It is divided into several types depending on the way the biomass is loaded.
- First type - portioned. In this case, after loading the substrate, it is unloaded only when it turns into a completely used material. However, this method has a disadvantage, which is that the gas production process is uneven throughout the entire processing stage.
- The second type is called continuous. From the name it is clear that the process of loading and unloading the substrate is carried out constantly. Thanks to this, it was possible to achieve that the release of a substance, that is, gas, became more uniform. In addition, such a problem of gas leakage through the nozzles through which raw materials are loaded and unloaded has been solved, since devices withwater seals.
Recycling process
In order to successfully determine what type of equipment is needed on the site, you need to know the principle of operation of a biogas plant. Do-it-yourself batch reactors of any design are created, the main thing is that it does not leak gas. Previously, methanetanks with an elastic inflatable arch were often used. In our case, excess pressure will inflate a dome made of flexible polypropylene. Over time, the pressure increases and when a certain mark is reached, the compressor turns on, which pumps out the gas.
The principle of fermentation in the reactor is mesophilic, that is, it requires weak heating. However, due to the fact that the area of the elastic dome is quite large and it is too expensive to heat it all up. It is advisable to place such reactors only in those regions that are characterized by stable and constant hot weather.
Design Options
Assembling a biogas plant with your own hands according to the instructions will not cause trouble if you understand how the device works and know a few tricks. You also need to be clear about what type of installation you will be building.
There is an option in which manual loading is carried out, and the substrate is not mixed or heated. As the use of the installation for domestic purposes, this method is considered the most suitable. Reactor capacity must be between 1m 3 to 10m3 per day. With such sizes, from 50 to 220 kg of biomass per day will be needed. A reactor of this type is installed in a small pit, which means that it will have to be dug in the ground. Naturally, the dimensions of the pit must correspond to the dimensions of the fermenter. In addition, two nozzles are needed: one of them will be responsible for loading the substrate, the other for unloading. It is important to note here that they should be located on opposite walls of the reactor. The upper part of the pipes is above the ground, and the lower part should be located almost at the very base of the methane tank. This way the gas will not escape from the pipe as it will always be covered by biomass.
You will need to organize a hatch for access to the bunker and a water seal, which will prevent the spread of an unpleasant odor in the area. The pipe that will be used to remove biogas must be equipped with a valve that can be opened and closed as needed.
Installation features
Heed a few guidelines when installing this type of reactor.
- Firstly, waste material is removed naturally. This is done either during the loading of a new substrate, or in the event of excess gas in the reactor with the valve closed.
- The design of this type of biogas plant is quite simple and efficient. But here it is important to take into account that there is no possibility of mixing, as well as heating the mass. This means that it is advisable to use this typeinstallations only where a fairly mild and warm climate reigns. Mostly it is the south of Russia. It is possible to use a reactor of this design in the middle climatic zone, but on condition that the water underground layers run quite deep, and the fermenter itself is equipped with high-quality thermal insulation.
Unheated Stirred Design
A do-it-yourself home-made biogas plant is assembled in almost the same way as the previous version, however, with minor adjustments. A small modification significantly increases the efficiency of using the installation. The scheme and installation process are exactly the same as in the previous case, but here you need to add one more element - the mixing mechanism, which is located inside the bunker.
Constructing the setup is quite simple. All that is needed is to install a shaft inside, to which a certain number of blades will be attached. For successful installation, the installation of thrust bearings will be required. Since there must be a transmission link between the shaft and the lever, it is best to use a chain here.
Installation with heating and stirring
Heating is an operation that greatly increases the efficiency of decomposition due to the fact that when the temperature rises to a certain level, the rate of decomposition of biomass increases.
A biogas plant for a private home can also be assembled without difficulty. It is not only more perfect and versatile, but also more complex indesign plan. In addition, it is capable of operating in two modes - mesophilic and thermophilic. In other words, the range of decomposition and fermentation is between 25 and 65 degrees Celsius. In order to ensure pre-burning, it is necessary to install a hot water boiler, the pipe of which must pass inside the reactor and reach the opposite wall from the entry point. The design is quite simple, but effective. A huge plus is that the boiler can run on the same gas that the installation itself produces, that is, this system can provide fuel for itself.
Automatic installation
If do-it-yourself biogas plants for heating a house consume gas immediately when it is produced, then automated options are supplied with an additional element called a gas tank. This is a detail that acts as a temporary storage of matter, which makes it possible to accumulate. In addition, in this case, almost any temperature range can be used for efficient fermentation. The productivity of such an installation is much greater. With similar dimensions of the reactor per day, it is able to process up to 1.3 tons of biomass. Pneumatics will be responsible for loading and mixing. In addition, in such installations, the channel for the removal of waste raw materials is connected to two different departments. One of them serves for temporary storage, and the other, mobile, for immediate removal. It is not entirely reasonable to assemble a biogas plant with your own hands for this type of heating, since the installation is quite complicated, and the performancetoo big. Most often, such structures are installed in private farms.
Mechanized equipment
The main difference of this installation is that before entering the reactor, the biomass passes through a container with preliminary preparation of the substrate for processing. The supply of raw materials to the bunker itself, and after it to the reactor, occurs due to liquefied biogas, which is subsequently used for heating.
It is very important to note here that when assembling any do-it-yourself biogas plant for heating a house, you will have to carry out accurate engineering calculations. It is best if a specialist is consulted before installation.
Main Benefits of Using a Biogas Reactor
Any do-it-yourself biogas plant, the photos of which are presented in our article, provides several important advantages.
The first is, of course, waste disposal. This recycling method is less hazardous to the environment than, say, burying waste in the ground.
The second advantage is that biomass is a renewable resource. It is not gas or coal that is running out. In addition, during the processing of the substrate, carbon dioxide is not emitted into the atmosphere. Its small amount is released exclusively at the time of its use. However, its volume is much less than when using natural gas.
A very important advantage is that the owner can manage the production of biogas energy independently. If we compare the reactor with other sourcesenergy, like windmills or solar panels, they are more reliable and permanent.
