The absence of a furnace for coal or electricity in a house can always be compensated for using natural fossil fuels - firewood. Moreover, this resource will be significantly cheaper compared to expensive natural gas. That is why many owners today abandon modern methods of heating and are looking for alternative heat sources. In these cases, a design such as a pyrolysis boiler can come to the rescue. It’s quite possible to make such equipment with your own hands, but first you need to consider in more detail what this device is and how it works.
General concept of pyrolysis
The principle of the pyrolysis boiler is the thermal decomposition of substances having a complex chemical composition, while not entering into compounds with any other reagents. This means that the molecules of a particular element are split into lighter and more elementary parts. This phenomenon is called pyrolysis.
Such a scheme is widely applicable in those private homes where there is no stationary heating. It is worth noting that pure pyrolysis is characterized in that the decomposition of fuel into elements takes place without access of oxygen in a special vessel, and then the resulting gases enter the accumulator and are used if necessary.
The big advantage of such plants is that you can add materials for combustion directly during the operation of the device. In addition, this equipment can operate on any solid fuel and maintain the desired temperature for a fairly long period of time.
Pyrolysis Combustion Boiler Design
In such devices, the furnace consists of two parts. The first is a loading chamber - here, with a small amount of oxygen, the fuel burns and pyrolyzes, and all the gases released in the process burn out already in the second part of the device, called the combustion chamber. Secondary air already enters there, and heat dissipation is very insignificant.
The pyrolysis boiler is also distinguished by the fact that the separation of its two parts is carried out using a grate covered with briquettes. Air entering the air passes through the tree from top to bottom, and it is this property that distinguishes this equipment from other household heating appliances.
Such boilers have high aerodynamic resistance, which makes it necessary to have forced draft, which is sometimes carried out using a special smoke exhaust, rather than a standard fan in such cases.
The principle of operation of the pyrolysis boiler
As you know, pyrolysis combustion boilers operate on the principle that wood decomposes under the influence of high temperature, eventually turning into coal (solid residue) and a volatile mixture.
Due to the process occurring in the loading chamber, the generation of generating gas occurs, which, passing through the nozzle of the boiler, interacts with the secondary air and burns. The temperature is 1200 ° C. The resulting volatile mixture crosses the convective part of the heat exchanger, giving up its main energy, and then is discharged through the chimney of the device.
Both internal chambers of this equipment are coated with a special lining that prevents the penetration of fire. This makes it possible to increase the temperature inside the apparatus and create the most favorable and effective conditions for burning wood.
Advantages of a wood-fired boiler
When making a pyrolysis boiler with your own hands, it is important to remember the main advantages of this equipment, which distinguishes it from similar devices used for heating.
The large volume of the loading chamber and high efficiency make it possible to maintain a given temperature for a rather long period of time compared to traditional devices. There are models that are quite capable of working 24 hours with just one tab of fuel.
Pyrolysis boilers practically do not need to be cleaned, since soot does not form in the combustion process, and the amount of ash obtained is minimal.
The combustion products in this equipment are less harmful to health, if we compare this indicator with other devices, since the amount of substances on a carcinogenic basis in them is significantly less. The mixture obtained at the outlet mainly consists of carbon dioxide and water vapor, which is unlikely to be hazardous to human health.
Another indisputable advantage that a pyrolysis boiler has for a home is the ability to regulate power over very large limits (from 30 to 100%). In addition, such a device has the function of disposing of waste without air pollution, which has a positive effect on the environmental situation and the indoor climate.
Fuel used for pyrolysis combustion boilers
The optimal fuel used for such equipment is wood, which has a length of about 400-450 mm and a diameter of 100 to 250 mm. Together with whole logs, sawdust can also be burned, but such waste should not occupy more than 30% of the volume of the loading chamber.
It will be most correct to use that material whose moisture index does not exceed 40%. This will not only make the device more efficient, but also extend its operational life. Such protective measures are easy to explain: 1 kg of wood with a moisture content of 20% emits 4 kW / h of energy, and with a humidity of consumables of 50%, only 2 kW / h can provide the same amount.
From this it follows that the heat and efficiency of fuel combustion directly depend on the amount of water contained in it: the more it is, the worse the result will be. Therefore, immediately before loading the wood, it is important to make sure that it is well dried and does not contain excess moisture.
Schemes for creating a pyrolysis boiler
To understand how much material you need to use during installation, it is recommended to seek help from special schemes for the construction of such equipment. Various drawings of the pyrolysis boiler can always be found at specialists engaged in similar works.
So, the diagram of this apparatus, as a rule, displays the location of the furnace, heat exchanger, as well as the area where water will be supplied.
It is very important to correctly connect all parts of the boiler in accordance with the drawing, so that the entire structure works properly and reliably. Do not forget that the coolant is air, which can warm the room without extra costs. This fact allows you to save a significant part of the financial resources spent on heating, especially in comparison with other structures for this purpose.
Pyrolysis boiler making tools
For the independent creation of this equipment it is required to have a certain set of auxiliary materials. In addition, it is necessary to collect a maximum of information about the work process, starting with consumables and ending with assembly. After that, it is necessary to correctly calculate all the parameters in order to determine what the optimal type of combustion should be, suitable for a particular room, since there can be two of them: either with a slit burner or on grates. All the materials necessary for installation can always be purchased in specialized construction stores, since today there should not be any problems with a choice.
So, the manufacture of a pyrolysis boiler requires the following tools:
- steel sheet 4 mm thick;
- iron pipe with the same parameter;
- set of electrodes;
- round rod with a diameter of 20 mm;
- several pipes of profile type;
- temperature control devices;
- centrifugal fan ;
- asbestos cord;
- fireclay bricks;
- bolts and nuts acting as fixing material.
Pyrolysis boiler assembly
The algorithm of actions for the independent manufacture of such equipment must necessarily rely on the drawing of a pyrolysis boiler for long burning. The assembly process of this device takes place in several stages:
- First of all, it is necessary to cut steel sheets and pipes, creating from them blanks for the boiler body, its furnace and cooler. It is important not to forget to process the edges of the material using a grinding wheel and outline areas for welding.
- After that, you should prepare the entire tool required to assemble the device.
- Then you can begin the process of creating the body. It follows the following principle: the end wall is laid on the welding table, after which side edges, the cover and the bottom, which are held by struts, are attached to it by means of point seams.
- Next, the process of installing the boiler furnace, which inside the entire system is presented in the form of horizontal shelves covered with a grate, should follow . Also attached to it is a neck pipe that performs the function of diverting olefins.
- After this, it is necessary to begin the assembly of filtration and gas cooling columns, which go through the furnace body and slightly extend beyond it. They are based on pipes installed in holes previously made in the housing.
- Then it is necessary to make the device of the second chamber of the boiler, which should be connected to the cooling column. At the same stage, you can install a second wall parallel to the housing in order to establish heating. It is separated from the first by a partition.
- The assembly process continues with the installation of an air exchanger and a chimney pipe.
- The last step is to install the last (front) wall of the body, equipped with doors and blowers.
This method of how to make a pyrolysis boiler with your own hands is the most tested and reliable, it is quick and relative ease of use.
Is it possible to make a furnace from a cylinder?
Often, the owners, not having at hand the necessary materials for assembly, decide to design the boiler from improvised means. Particular attention is paid to the capacity for liquefied gas, which has a rounded shape and a suitable size. In addition, the wall thickness of such a vessel corresponds to the desired parameters.
Nevertheless, it is not recommended to make a pyrolysis boiler from a gas cylinder. This is primarily due to the fact that the case of such a device consists of standard steel, which does not tolerate heat and other chemical influences even at room temperature.
However, you should not completely abandon the cylinder, since it can play the role of a hot water storage device in a small private house, in addition, due to its small size, heating will be carried out quickly, and its shape will allow it to retain heat for a long time even when using the simplest insulation. But if you decide to use such a cylinder, the drawings of the pyrolysis boiler will be completely unnecessary - then it is better to refuse to install it.
Necessary operating conditions
The operation of the pyrolysis boiler, like any other device that functions when exposed to fire, is certainly associated with some risk. Therefore, it is important not only to properly equip the entire system, but also to take care of safety rules.
So, making a pyrolysis boiler with your own hands, you need to take into account the following points:
- installation should be carried out exclusively in non-residential premises;
- it is desirable that the base under the boiler be made of concrete or brick in order to avoid excessive heating of the coating;
- the device should be positioned so that it is no closer than 30 cm from the walls and objects in the room;
- It is important to provide a room with a boiler with good ventilation, so that the fumes emitted during operation go out.
In addition, it is important to remember one more thing: at the end of the installation of equipment it is extremely important to insulate its chimney with mineral wool so that tar and condensate do not accumulate from the inside of the pipe.
An alternative to a pyrolysis boiler
Despite a well-regulated method of manufacturing such a device, some owners have found ways to make it using other materials.
According to many, it makes no sense to design a boiler with a capacity of less than 15 kW. But sometimes you don’t want to create such massive samples, especially if the area of the room is small. It is for these purposes that there is an option to create a pyrolysis furnace, similar in its properties and external characteristics to the boiler. It is not worth worrying about the functioning of such equipment, since the principle of fuel combustion in it is similar.
For the manufacture of this sample will need the following series of materials:
- fireclay bricks;
- fan;
- steel sheet approximately 4 mm thick;
- ceramic bricks;
- doors used for blowing and combustion chamber;
- cast-iron grates;
- lever temperature thermostat.
Such a furnace is an alternative to a standard pyrolysis combustion boiler and is fully suitable for installation in any room. If you want to save financial resources, such a device will become indispensable and will provide an opportunity to heat the entire building with high quality and long time.