Many owners very often encounter the following problem: how to safely and efficiently heat your home if gas is not connected to it? The answer to this question can be only one: it is best to use a special installation in the form of a boiler working on wood on the principle of pyrolysis combustion. You can purchase such a device in a specialized construction store, but its cost will be quite high. That is why it is necessary to consider in detail how to make a home-made pyrolysis boiler, as well as pay attention to the features of its functioning.
What is pyrolysis combustion?
As you know, it is not very convenient to heat a room with firewood, since this fuel burns quickly, without releasing the right amount of energy. However, if the oxygen content in the furnace is reduced, the material will be consumed much more slowly. It is precisely on this that the principle of pyrolysis combustion is based, due to which fuel is required much less, and efficiency increases. The main products obtained in this case are coke, ash, and also combustible gas, which also emits a large amount of heat.
This means that, when designing a home-made boiler for long burning, it is necessary to take into account the following points:
- Initially, wood, burning with a limited supply of oxygen, emits combustible gas;
- further, the resulting mixture is burned, giving off, in turn, heat.
Many home-made boilers work on this principle, but it is important to remember that the equipment must be adjusted so that during its operation the general system for providing heat to the home is not damaged.
Wood boiler design
The furnace of such devices is divided into two parts. The first of these is called the boot camera. It is in this section of the boiler that the wood burns, undergoing pyrolysis. Accordingly, the air volume here is minimal. All
gases obtained during the
operation go, in turn, into the second part, which is called the combustion chamber. Moreover, it is worth noting that heat loss in this case is insignificant.
When making a homemade boiler on wood, it must be borne in mind that the separation of the two above-mentioned chambers is carried out by means of a special grate. The air entering the mechanism at first completely passes through the fuel, which is typical exclusively for pyrolysis devices.
The aerodynamic drag of such devices is very high, which makes it necessary to install additional traction, which can function not only with a conventional fan, but also with a special smoke exhauster used specifically for these cases.
Technical features of the pyrolysis boiler
The high temperature affecting the wood inside the mechanism causes it to decompose, which leads to the formation of coal and combustible gas.
Home-made solid fuel boilers during operation create a very significant amount of heat. This is due to the fact that the temperature inside the combustion chamber can reach 1200 ° C, as a result of which gas evolution proceeds very quickly.
The combustion products of the resulting volatile mixture, having given up most of the energy, are subsequently output through the chimney installed on the apparatus.
Due to the large volume of the loading chamber, the temperature can be kept constant over a long period of time, which cannot be said about standard heating appliances. So, a home-made wood-burning boiler can function without stopping for a whole day, and it is enough to load wood into it only once. In addition, you can always adjust the power of the device as you wish.
It is possible to clean such equipment, but rarely, since no soot is formed during operation, and ash is produced in minimal quantities.
It should also be noted that these devices are environmentally friendly, since the exhaust gases are nothing more than a combination of water vapor with carbon dioxide.
Nevertheless, it is worth mentioning some of the negative aspects of the pyrolysis boiler. So, it is customary to distinguish the following from them:
- the equipment has rather large dimensions, which may not be very convenient in a small room;
- for quality work, it is important to use only well-dried fuel, otherwise the thermal return will be much less;
- normal functioning of the boiler is possible only under the condition of a stable network connection, which is associated with the need to maintain forced draft, the main mechanism of which is the built-in fan.
But, as it becomes clear, this equipment has more advantages than disadvantages, so its installation will be definitely the right solution.
Optimum fuel for a wood-fired boiler
The best material for heating used in pyrolysis boilers is, of course, wood. Moreover, the ideal parameters for it are the following: length 400–450 mm, diameter 100–250 mm. It is not forbidden to burn sawdust along with logs, but it is important to remember that such fuel should not exceed 30% of the total volume of material placed in the loading chamber.
As mentioned above, a home-made long-burning boiler will work with maximum efficiency only on dry wood, that is, one whose moisture content does not exceed 40%. In addition, such measures will not only increase the capacity of the equipment, but also extend its service life.
Therefore, it is important to make sure in advance that the fuel is well-dried and does not contain a large amount of moisture, otherwise the device will be less efficient.
Drawings for long-burning boilers
Any independent production of one or another equipment must necessarily be accompanied by consultations with various schemes of the mounted device. So, drawings of home-made pyrolysis type boilers can easily be found both in various construction organizations involved in the assembly of such equipment, and on the Internet.
These plans usually reflect the location of the functional parts of the future device (firebox, chimney, heat exchanger, etc.). Often, the exact dimensions of the mounted structure are also applied to them, which, of course, facilitates the entire process. The main thing is to be able to understand the drawings and follow the instructions.
Do not forget that in case of improper assembly, the device may not work at best, and at worst it may become a security threat, since any manipulations with fire, as you know, require strict observance of safety measures. A poorly mounted design can lead to unforeseen consequences, so all steps must be performed correctly and carefully.
Materials for self-assembly of the boiler
In order to properly make a home-made pyrolysis boiler, the necessary materials and tools should be available. Here is a list of them:
- electric drill;
- several packages of electrodes;
- apparatus for welding (preferably direct current);
- 230 mm cutting wheel ;
- Bulgarian;
- grinding wheel 125 mm;
- sheets of metal 4 mm thick;
- refractory bricks ;
- pipes of various diameters;
- several profile pipes 2 mm thick;
- fan;
- temperature display sensor;
- a number of steel strips with different thicknesses and widths.
In the case of such equipment, it is better to use 4 mm steel. However, it is possible to construct home-made boilers with the help of a material 3 mm thick, which is usually done in order to save.
The process of manufacturing a long-burning boiler
The assembly process begins with the cutting of four walls for the future device from finished sheet steel. At the same time, two holes must be cut out in the front face using a grinder, one of which is intended for an ash pan, and the other for a furnace.
The back of the boiler can still not be touched, and the remaining three must be firmly welded to each other. Coarse seams formed as a result of work should be carefully sanded with a grinder.
Homemade solid fuel boilers have in their design a heat exchanger, all of its components must also be tightly welded, and the growths that appear should be cleaned. Then you can begin the installation of this device directly into the furnace.
It is better to position the firebox, unlike factory models, at the top, and not below. Using the grate, it is required to separate it from the gasification compartment, located above. The combustion chamber must be lined with refractory brick, laying it on all sides.
Then you can mount the doors, while it is important to provide them with a maximum fit to the walls of the structure.
Having made a chimney, you need to fix the sensor to determine the temperature, the main function of which is to control the combustion process and display the power of the boiler.
Next, you need to cut out the holes intended for all pipes, fix the back wall with a welding machine and process uneven corners. The assembly process is completed by checking the operation of the finished device. The absence of carbon monoxide emitted means that the equipment is fully operational.
It is according to this scheme that the simplest home-made boilers should be mounted, the principle of which is based on pyrolysis.
Recommendations for assembling a wood-fired boiler
To ensure that during the manufacturing process there are no serious difficulties, and the equipment subsequently works reliably, it is recommended to pay attention to the following recommendations that can help during installation:
- It is extremely important to equip the system with a limiter that allows you to control the air entering the combustion chamber. For its construction, a pipe having a diameter of about 70 mm, while having a slightly longer length in comparison with the case of the device, is suitable. A steel disk should be welded to the lower part of the limiter, which should be at a distance of about 40 cm from the base walls, and the boiler cover must be equipped with a special recess for its installation.
- Homemade heating boilers require a hole for loading firewood in the shape of a rectangle. It must be closed with a door, which is equipped with a special steel plate that provides a more tight grip with the body.
- The heat transfer pipe must have a bend. This will help make the energy output stronger.
Pyrolysis boiler operation tips
It is very important to ensure that the operation of this equipment takes place in a safe environment and does not pose any threat to others. So, it is worth remembering that there are some rules governing the operation of such a mechanism. These include the following:
- you can install homemade boilers exclusively in non-residential buildings;
- the device should not be near walls and other objects in the room closer than 30 cm;
- for the safety of the operation of the apparatus, it will be more correct to install it on a concrete or brick base;
- it is extremely important to equip a room with a boiler with good ventilation so that combustion products do not accumulate indoors, but go out;
- to protect the chimney of the device from condensation, it is recommended to insulate it with mineral wool.
Compliance with these simple rules will allow not only to achieve the maximum efficiency of the boiler, but also significantly extend its service life and eliminate the need for any repair work.