Assembling a biogas plant with your own hands is a very real undertaking. In addition, the cost of such work will be much lower than the purchase of a ready-made model. The resulting resource can be used to heat the house, cook food and for many other needs.
General information
It's worth starting with the fact that the extraction of this substance is carried out as a result of the process of fermentation of a biological substrate. Here we can add that the composition of the resulting gas is practically no different from ordinary natural gas, which is used very actively in people's lives. Thanks to this, some owners were able to run a car on biogas with their own hands.
Another important fact is that biogas is an environmentally friendly raw material, the production of which does not have a negative impact on the environment. Waste that needs to be disposed of became the starting material for obtaining this resource. For this, there is a special reactor in which several processes take place:
- Biogas production begins with the fact that the biomass loaded intocontainer is exposed to certain bacteria. The duration of this processing depends on how much of the substance was loaded inside.
- Anaerobic bacteria are active inside the reactor. Under their influence, the raw material decomposes and a combustible mixture is released. The composition of this substance is approximately the following - methane 60%, carbon dioxide 35% and another 5% of some other volatile gases. It is very important to note here that as a result of fermentation, hydrogen sulfide, which is a potentially hazardous substance, can be released in small quantities. Protective equipment required.
- The do-it-yourself biogas plant has certain filters that clean the gas from other unnecessary components. After that, the resource enters the gas tank - storage, in which it remains until the moment of its use.
- You can use the gas that is in the gas tank in the same way as ordinary natural gas. You can connect the storage to a gas stove, boiler, etc.
- The place where the biomass is located is called the fermenter. It is necessary to regularly remove the used substance from this section. This is considered an additional labor cost, but it pays off - such biomass is considered an excellent fertilizer for use in vegetable gardens.
Who benefits from having recycling equipment
It is worth saying that it is not always profitable to have such equipment. Firstly, for effective and permanent work, it is necessary to have access to waste from animal farms. Secondly, the development of thissubstances is carried out unevenly and strongly depends on the temperature of the biomass itself, which is loaded inside. As practice shows, from 1 m3 of substance, you can get from 70 to 80 m3 of biogas for home heating with your own hands.
In order to stabilize the production of gas, as well as to make this process continuous, it is recommended to have several installations. The bottom line is that it is necessary to lay the biomass with a certain time difference in different reactors. In this case, the production of the desired substance will be carried out in parallel, but the loading will be sequential.
As for self-assembly of such equipment, it should be understood that its efficiency will be lower. However, the cost will be significantly lower than the price of an industrial installation, and therefore it is safe to say that the homemade product will work out its money.
Pros and cons of having a system on the farm
Installing equipment for producing biogas in a country house with your own hands has both positive and negative sides, and therefore, before starting work, you need to think it over.
- One of the obvious advantages is waste disposal. The presence of such a device will allow you to more effectively, and most importantly, safely dispose of unnecessary waste.
- The second plus is the constant renewal of raw materials. Biomass is a substance that is always in abundance if you have your own farm.
- Low CO2. In the processing and production of biogascarbon dioxide is not emitted into the atmosphere at all. Some will be released into the air when it is used, but this is not critical, since its content is small, and it will be absorbed by the surrounding plants.
- The biogas plant can work stably. If we compare this equipment with other sources, for example, solar panels or wind turbines, they are not stable, but biogas production is completely dependent on the owner's activities.
Despite this, such installations still have disadvantages. Of course, biogas is a much cleaner material, but still its use leaves a small residue in the atmosphere. In addition, there may be occasional problems with the supply of plant biomass. Too greedy use of such reactors will lead to the fact that the balance in a certain area will be upset.
Getting Started
To get started, you will need a drawing for biogas (you can do everything almost from scratch with your own hands at home). The drawing shows the installation or the entire system if more than one reactor is planned to be installed. However, if this is your first build attempt, it's best to start simple and focus on building just one object. It is also worth adding that the simpler the installation scheme, the more reliable and durable it is considered.
It is very important to calculate the volume of the fermenter - this is where the biomass will be stored. It is recommended to make it so that 5 m3 of raw materials can fit inside. Thisenough to easily heat a private house with an area of up to 50 m22 if a gas boiler or stove is used.
In order to maximize the stabilization of the fermentation process inside the chamber, it is necessary to create an acceptable temperature regime. For this, an earthen hole is most often dug, inside which the object is located. If this is not possible, then it is necessary to create reliable thermal insulation in another way. Some owners run a pipe with water heating under the fermenter to ensure constant heating of the substance.
Preparing the recess
Hand-made biogas equipment, the drawings of which should already be ready, almost everything is placed underground. That is why it is very important to carefully prepare the earthen pit. Currently, several materials are used for thermal insulation of the pit. It can be plastic, concrete, polymer rings.
The intensity of fermentation, as well as the rate of gas release, will depend on how well the bottom and the walls of the pit are prepared. In addition, this stage is considered the most difficult and time-consuming. The most optimal solution is the purchase of polymer rings with a blank bottom. This product, of course, will cost more than improvised materials, however, the installation of this material does not require the arrangement of additional sealing, which saves time, money and effort. It is also worth remembering that polymers are quite sensitive to mechanical stress, and therefore handlethey stand neatly, but at the same time they are very resistant to aggressive chemicals, and they are also not afraid of moisture, which plays a key role. Such material cannot be repaired, but it will be quite simple to replace it with a new one.
The process itself is quite simple and clear. It is necessary to dig a recess of the required size, and then engage in mounting polymer rings.
Arrangement of system elements
To produce biogas with your own hands at home, you must have a system of special agitators. However, their acquisition and installation is considered quite expensive, and therefore you can do otherwise. You can significantly reduce material costs by installing gas drainage. To do this, it is necessary to have a certain number of sewer polymer pipes that are installed in a pit in a vertical position. Many small holes are made in them.
It is worth noting that not only polymeric, but also metal pipes can be used. Their advantage is that they are much stronger in terms of mechanical stress than polymers, which are more resistant to chemical attack. However, a significant drawback of the metal lies in the rapid occurrence of corrosion, and therefore it is still better not to install them.
As for the length of the pipes, it is calculated based on such a value as the filling height of the fermenter. Pipes should be slightly higher than this figure. After that, the bioreactor is already considered ready for operation, and you can proceed todo-it-yourself biogas production at home. However, since it still does not have a dome, it can be covered with a film so that the gas that will be released during the fermentation process remains inside and is under slight pressure. Continuous gas supply in normal mode will only be possible after the installation of the dome and outlet pipe.
The final stage is the assembly of the dome and pipes. Here, too, everything is quite simple. The finished reactor is closed from above with a "lid", which has a domed shape. At the highest point of this part, a gas outlet hose is fixed, which goes to the gas tank. It is important to note here that the free space inside the dome is a small amount of gas storage, but there is not much of it. For this reason, gas must be constantly consumed, otherwise there is a risk that an explosion will occur due to excess pressure under the dome.
In order to prevent the displacement of gas and air, it is necessary to tightly close the reactor with a lid. Quite often, a water seal is equipped so that precipitation does not get inside. Another important element is the installation of a system that will control pressure. You need a valve that will open and release some stuff if the pressure gets too high.
Heating the fermenter
In order to equip your own home with biogas heating, you need to carefully heat the fermenter itself. Here you need to know the following. Microorganisms that process the substrate are always present in the biomass. However, for themsuccessful functioning and reproduction requires a constant temperature of 38 degrees Celsius. In order to heat up the reactor in winter, for example, a coil can be used, which is connected to the heating system of the house or an electric heater. However, the use of electricity for these purposes is usually much more expensive, therefore it is connected to the heating system in order to reduce the cost of the process of heating with biogas by one's own hands.
The easiest way is to lay a pipe under the reactor itself. However, the efficiency of such a system is quite low. It is best to do the arrangement of external heating. The ideal option is to have a heating system using steam so that the biomass does not overheat.
Feedstock
Getting biogas from manure with your own hands is quite simple. As studies have shown, in the manure of any animal initially there is a huge amount of microorganisms that are enough for its processing. The vast majority of such organisms belong to the group of methane-formers, so gas production became possible. To make the extraction of the substance as efficient as possible, you need to know which raw materials are best used. It has been proven that combining plant mass as well as cattle biomass will release the maximum amount of volatile matter.
However, simply combining these substances and pouring them into the reactor will not be enough. To maintain high productivity of biogas production from manurewith your own hands, it is necessary that the humidity of the substrate is always in the region of 85-90%. It is important to know that wetting water should only be used that does not have other chemical impurities. Another important nuance is that for an effective process to proceed, there should not be large fragments in the liquid. If the plant part is also added to the biomass, then it will have to be crushed first.
In addition, one of the important factors was the maintenance of the pH at the right level of the substance. The limits that are considered normal are 6, 7-7, 6. Usually, the quantitative content of acid is normal in itself and rarely develops faster than bacteria from the methane-forming group. However, if this does happen and acid builds up faster, gas production will decrease. In order to stabilize the process, it is necessary to add ordinary soda or lime to the substrate.
Loading and unloading material
As for the location of the loading and unloading hatches, they should lead directly to the reactor vessel. It is important to note here that they should be located lower than the substrate. This must be done in order to avoid air getting inside the fermenter. In addition, the pipes must be at an acute angle. Loading and unloading hatches should be on opposite walls. These openings must have a cover with which they will be closed throughout the entire period of operation.
Another nuance concerns the fact that manure can contain a variety of elements, for example, grass stalks. It means thatthe pipe in a do-it-yourself biogas plant must be wide enough. If it is small in diameter, it will clog too quickly. The optimum diameter of the pipe is from 20 to 30 cm. It is worth adding that the installation of pipes is carried out before proceeding with the arrangement of thermal insulation, but after the installation of the fermenter in the pit.
Maximum efficiency from a do-it-yourself biogas plant can be achieved if you regularly load new raw materials and unload old ones. Such procedures should be carried out either once a day, or once every two days. A little trick is that when calculating the depth of the pit, you need to make it such that the biomass flows down into the fermenter by gravity.
Cleaning
As mentioned earlier, after the processing of biomass, not only methane-forming substances are released. In order to get rid of an unpleasant odor, as well as to achieve maximum combustion from a substance, it must be cleaned. You need to remove impurities such as carbon dioxide, hydrogen sulfide, water vapor. Removal of CO2 is carried out in a water seal. It is quite simple to equip it - it is necessary to place slaked lime on the bottom of the fermenter. However, this bookmark will sometimes have to be changed. When the gas starts to burn worse, then it's time for a replacement.
There are two different ways to dry the gas. In the first case, it is possible to equip water seals in the gas pipeline. Curved sections are inserted into the pipe, which will be used as gates. Condensation will accumulate in these places. However, the method has a disadvantagewhich consists in the need to periodically clean the valve from condensate, since if there is too much liquid, the gas will stop passing.
The second way is to install a silica gel filter. The principle of operation here is the same as in the water seal. The gas passes through it, and then it is fed already in a dried form. If you use this method, instead of cleaning the shutter, you will have to periodically dry the silica gel compartment, which absorbs moisture.
