Recently, prices for electricity, energy and other equipment are gradually increasing. This means that it costs more and more to pay 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 buy 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 within which anaerobic decomposition of biomass occurs. The reactor is called a fermenter or methane tank.
To date, there are several main types of such structures. These include completely sealed reactors with a fixed or floating dome and reactors that resemble a conventional diving bell in design.
A brief description of the bell type
Designing a do-it-yourself psychrophilic biogas plant bell is 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 bell. It collects biogas released during decomposition. The substance that accumulates 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 lid, a stalemate arises altogether. Plus, the lack of a sealed cover leads to the fact that the installation emits some of the gases into the atmosphere, thereby polluting it. For these reasons, do-it-yourself bell-type biogas plants are usually assembled either for handicraft production of plants, or in countries where the weather is constantly hot.
Fermenter with a dome
In order to get rid of the main disadvantages and minimize atmospheric pollution, bioreactors with a fixed dome are used. It is these models that are most often used during installation at industrial facilities or on sections of private houses. By the way, it is worth noting that DIY assembly of a biogas plant for the home has recently become a fairly popular activity.
It is worth noting that the shape of the dome does not affect the process of gas generation itself, but if you execute it in the form of a cylinder with a dome roof, you can achieve maximum savings in building materials. There is one big BUT: since the reactor is completely closed, it should be equipped with nozzles through which a new substrate will be loaded and the old one will be cleaned.
Types of Installations
Since a do-it-yourself installation for a biogas plant with a closed dome is most suitable for home, let's look in more detail at its simple design. It is divided into several types depending on the method of loading biomass.
- The first type is portioned. In this case, after loading the substrate, it is unloaded only when it turns into a completely waste material. However, this method has a minus, which consists in the fact that the process of gas production 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 ongoing. Thanks to this, it was possible to ensure that the release of a substance, that is, gas, became more uniform. In addition, this problem of gas leakage through the nozzles through which the raw materials are loaded and unloaded has been solved, since devices with hydraulic locks are used here.
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. With their own hands, batch reactors of any design are created, the main thing is that it does not leak gas. Earlier, methane tanks with an elastic inflatable arch were often used. In our case, overpressure will inflate a dome made of elastic polypropylene. Over time, the pressure increases and when a certain point is reached, a compressor is turned 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 large enough and it is too expensive to heat it all. It is advisable to place such reactors only in those regions that are characterized by stable and constant hot weather.
Assembling a biogas plant with your own hands according to the instructions will not be a hassle if you understand how the device works and you know a few tricks. You must also clearly understand what type of installation you will be assembling.
There is an option in which manual loading is carried out, and the substrate does not mix and does not heat up. As a use of the installation for domestic purposes, this method is considered the most suitable. The capacity of the reactor should be in the range from 1 m 3 to 10 m 3 per day. With such sizes, it will take from 50 to 220 kg of biomass per day. A reactor of this type is installed in a small pit, which means that you have to dig it in the ground. Naturally, the dimensions of the pit should correspond to the dimensions of the fermenter. In addition, two pipes 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 should be located almost at the very base of the methane tank. Thus, the gas will not exit the pipe, as it will always be covered by biomass.
It will be necessary to organize a hatch for access to the hopper and a water lock, which will prevent the spread of unpleasant odors in the area. The pipe that will be used for biogas removal is necessarily equipped with a valve that can be opened and closed as necessary.
When installing this type of reactor, listen to a few recommendations.
- Firstly, the removal of waste material is carried out naturally. This is done either during the loading of a new substrate, or in the event of an excess of gas in the reactor with a closed valve.
- The design of a biogas plant of this type is quite simple and effective. But here it is important to consider that there is no possibility of mixing, as well as heating the mass. This means that it is advisable to use this type of installation only where a rather mild and warm climate prevails. Mostly it is the south of Russia. You can use a reactor of this design in the middle climatic zone, but provided that the underground water layers lie quite deep, and the fermenter itself is equipped with high-quality thermal insulation.
A do-it- yourself home- made biogas plant is assembled in almost the same way as the previous version, though with minor adjustments. Minor improvements significantly increase the efficiency of the installation. The layout and installation process are exactly the same as in the previous case, however, here you need to add another element - the mixing mechanism, which is located inside the hopper.
Designing an installation 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.
Heated and Stirred Unit
Preheating is an operation that significantly 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.
Do-it-yourself biogas plant for a private house can also be assembled without difficulty. It is not only more perfect and universal, but also more complex in terms of design. In addition, it is able to work in two modes - mesophilic and thermophilic. In other words, the decomposition and fermentation ranges from 25 to 65 degrees Celsius. In order to ensure burning, it is necessary to install a hot water boiler, the pipe of which must pass into 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.
If biogas plants do-it-yourself use gas to heat the house immediately when it is generated, then the automated options are supplied with an additional element called a gas tank. This is a part 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 effective fermentation. The performance of such an installation is much greater. With the same dimensions of the reactor per day, it is capable of processing up to 1.3 tons of biomass. Pneumatics will be responsible for loading and mixing. In addition, in such installations, the channel for removal of waste raw materials is connected to two different departments. One of them serves for temporary storage, and the other, mobile, for immediate export. To assemble a biogas plant with your own hands for heating of this type is not entirely reasonable, since the installation is quite complicated and the productivity is too big. Most often, such structures are installed in private farms.
The main difference of this installation is that before entering the reactor, the biomass passes through the 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 that when assembling any biogas plant with your own hands for heating the house, you will have to carry out accurate engineering calculations. It is best if you consult with a specialist before installation.
Key Benefits of Using a Biogas Reactor
Any biogas plant with your own hands, the photos of which are presented in our article, gives several important advantages.
The first is, of course, waste disposal. This processing method is less hazardous to the environment than, say, landfill.
The second advantage is that biomass is a renewable resource. It is not gas or coal that ends. In addition, when processing the substrate, carbon dioxide is not emitted into the atmosphere. Its small amount is allocated 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 control the production of biogas energy independently. If we compare the reactor with other energy sources, such as windmills or solar panels, then they are more reliable and constant.