Heating systems equipped with pyrolysis boilers are modern, productive devices that create comfortable conditions in the building. At the same time, a large amount of heat is released at minimal cost.
Boilers operating on the basis of the pyrolysis process are in some cases the main sources of heat in residential and industrial premises. Inexpensive fuel and a high level of efficiency, a system of reliable control over the optimal combustion process are the advantages that influence the choice of this heating equipment.
In these units, pyrolysis gas is produced, obtained by burning firewood. A temperature of no more than 8000 is created in the furnace and a low oxygen content is provided. The pyrolysis gas mixes with air and burns completely in the afterburner.
The principle of operation and types of pyrolysis boilers
The industry produces 2 types of equipment:
- mine boilers with top fuel loading;
In this case, the combustion of fuel passes from the top to the bottom. In the firebox there are grates that divide it into several compartments. Solid wood or other type of fuel is loaded here. When ignited, pyrolysis gas is formed in the upper part, which descends into the lower chamber. Here, mixing with secondary air and afterburning takes place.
As the gas descends, the lower part of the wood warms up, so damp wood can be used. In order for the gas to go down and to stabilize the thrust, the design provides for the installation of a fan. It is mounted at the top of the boiler. Air is supplied from top to bottom, so this is a "top blast" installation.
To improve the process of afterburning gas, some models provide for the installation of an additional supercharger. In this case, the air flow passes directly into the lower chamber. This design increases the productivity of the equipment. The removal of smoke and steam is carried out through the smoke pipe into the ventilation system.
Bottom loading units
Gas generating chambers in this type are located in the lower part. The gas passes to the upper part and here it is afterburned. For normal operation of the equipment, the height of the chimney must be at least 5 m. This type of boiler does not use blowers, so they do not depend on the supply of electricity. But the performance of this type is lower.
Regardless of the type of equipment, pyrolysis boilers with a water circuit operate according to the following algorithm:
- fuel is loaded into the chamber;
- using the regulator, a certain type of boiler operation is set;
- after heating the combustion chamber, air access is blocked. Fuel smolders, there is an increased release of carbon monoxide;
- pyrolysis gas passes into the afterburner compartment, mixing with oxygen, and completely burned.
It is interesting! According to experts, the equipment operates at full capacity when burning dry hardwood. The length of firewood should not exceed 600 mm, and the humidity should not exceed 20%. Such fuel will extend the performance of the equipment and achieve its maximum performance.
Advantages and disadvantages of pyrolysis boilers
This type of heating equipment is far superior to direct combustion stoves in several ways. These include:
- impossibility of soot formation. This is due to the complete combustion of solid fuel. In addition to the economic component, this feature makes pyrolysis boilers more environmentally friendly. In this case, the waste products are carbon dioxide and water;
- any solid fuel can be used. This is due to its complete combustion. Any substance capable of burning can be used. It can be installed in leather production, agricultural enterprises, sewing shops for waste processing and space heating. At the same time, production waste is completely recycled;
- the pyrolysis process, when burning hard wood, can last more than 10 hours. A direct combustion stove gives heat for 4 hours;
- the operation of the unit can be regulated. In this case, the process of fuel combustion and heating of water in the circuit is regulated. Ease of adjustment is due to the combustion of gas and the ease of regulation of its flow. This feature allows you to set automatic adjustment and secure the operation of the boilers.
The disadvantages of this equipment include:
- high cost, but the cost of the purchase will quickly pay off. This is due to the advantages of the pyrolysis boiler and the complete combustion of the fuel;
- a prerequisite for the use of dry fuel. At humidity more than 20%, the equipment may work intermittently;
- for the normal operation of mine boilers, an electrical supply is required to force air into the afterburner. Such equipment cannot be used in places remote from power lines.
Important! According to the owners of pyrolysis equipment, work may be disrupted due to the low temperature of the water coming from the return pipeline. To prevent inconvenience, it will be necessary to install a three-way valve when installing a water heating system to divert hot water into the return line. Thus, by heating the cold water of the return pipe, you will avoid trouble and shutdown of the boiler.
Basic rules and conditions for normal operation
For normal operation of the equipment, it is necessary to observe a certain range of fuel combustion temperature. This range is from 2000 to 8000 C. It is necessary to accurately configure the device. To prevent the occurrence of emergency situations at high temperatures, the water circuit of the unit is used. The body plays the role of a heat exchanger, water passes between its walls. This feature and the built-in coil in one of the walls prevents the creation of extreme temperatures.
If the water temperature is insufficient, the formation of pyrolysis gas stops, air is supplied to the combustion chamber and the boiler works like a conventional solid fuel furnace. It is not allowed to cool water below a temperature below 600 C. In this case, the combustion process without oxygen stops in any type of pyrolysis boilers.
To ensure a small water circuit and the transition of the equipment to working condition, an additional jumper (bypass) is installed in the water circuit. The bypass is manually adjusted, and temperature sensors are installed to control the temperature.
This type of equipment can work on all types of firewood, briquettes, pallets. In reality, such a type of fuel as coal can be used. Processing of combustible household and industrial waste is provided. But this can backfire due to their high polymer and rubber content.
Pyrolysis boilers are produced only single-circuit and cannot be used for heating water. But, in the absence of natural gas, to create comfortable conditions in the building, this type of equipment is the best solution to the problem.
Economical and efficient heating is the dream of any homeowner. Happy are those who have the opportunity to connect gas boilers, the rest have to choose between solid fuel boilers and electric ones. Solid fuels are good because heating is relatively inexpensive. Their disadvantage is that they need a constant presence in order to add fuel. But recent developments - pyrolysis-type long-burning boilers - have become more convenient in this regard.
On one tab of fuel, the system can be heated from 8 to 24 hours (depending on the fuel and ambient temperature). In the interval between laying firewood, it doubles, and you can check it at all once a month - such fuel can be supplied automatically as needed.
They have shortcomings. Not without it. Two main ones: the equipment is expensive and very often volatile (requires a guaranteed power supply). The price pays off during operation: on one tab of firewood, the house warms up twice as long, and on the tab - generally up to a day. In addition, there are boilers that burn everything: even construction debris and old tires. Anything that can burn.
Operating principle
How is it possible that so much energy can be obtained from such a small amount of fuel? The thing is that most of the heat in conventional boilers (they are called direct combustion boilers) literally "flies" into the pipe.
If you heat with wood or coal, you know that it is impossible to touch the pipe - the temperature there and 300 o C can be 400 o C. And in some cases (in baths, for example) even higher.
In pyrolysis stakes, air leaves the furnace with a temperature of 130-160 o C. This is achieved due to the fact that not only the energy released by firewood is used, but the gas that they emit during smoldering is also burned (a special mode is created for this).
The work is based on the fact that carbon-containing fuel (coal, firewood, pellets) when burned with a lack of oxygen, decomposes into a large amount of gases and combustible substances. Due to the fact that in the process of smoldering from wood or other carbon-containing fuel, a large amount of combustible gases is released, such devices are also called gas-generating boilers. For example, wood as a result of pyrolysis is converted into:
- solid residue - which itself is a high-calorie fuel;
- methyl alcohol;
- acetone;
- various resins;
- acetic acid.
All these substances burn and release a large amount of energy. Pyrolysis boilers therefore have two chambers:
- Fuel is placed in the combustion chamber and ignited to achieve the desired temperature.
- The gases released during the combustion of the fuel are discharged into the pyrolysis chamber (afterburner). They already have a high temperature, mix with the air injected there, and ignite.
Air is separately supplied to both chambers, the intensity of combustion and the power of the boiler at this stage are regulated by its quantity. This is the only fuel combustion technology that allows you to automate the combustion of wood or coal.
Advantages and disadvantages
Emission of gases during combustion in conditions of lack of oxygen is very active. Therefore, for the efficient operation of such equipment, automation is important, which will control the process: limit the oxygen supply after the firewood has flared up and regulate the process in both chambers. This is the main drawback of the stake: it needs guaranteed power to work (for the automation to work).
There is another positive point: pyrolysis gases interact with carbon during combustion. As a result of these reactions at the outlet of the boiler, the smoke consists mainly of carbon dioxide and water vapor with a small amount of other impurities. If firewood is used, CO emissions into the atmosphere are three times less than when using traditional technology. When working on coal, the situation is even more rosy - there is a five-fold reduction in emissions.
The afterburning of gases and the microparticles contained in it is also good because there is practically nothing to be deposited on the walls of the chimney: little soot is formed. And one more bonus: there is little ash left. Little ash and soot - less cleaning required. It's nice too.
Direct combustion boilers have an efficiency of about 60-65%. Pyrolysis - 80-90%. This is a tangible difference.
But the benefits aren't over yet. It is possible to regulate the power of a conventional boiler rather conditionally. All possibilities - open / close the doors, blowers and dampers. Moreover, you need to do this with your hands and rely on experience and intuition. The pyrolysis process can be adjusted over a wide range: you can leave 30% of the power, or you can “overclock” it to 100%. And the process is regulated by automation, which focuses on the specified parameters. Result: 40% fuel savings.
Structurally, cola can be made in different ways: in some models, the afterburner is located under the primary, in some - on top. There are models in which it is located behind the primary firebox. In some units, air is supplied not from below the firewood through the grate, but is “blown in” from above, slowing down the combustion process. They are all variations of the same technology. But they also have their pros and cons. Let's consider some of them in more detail.
Blago Features
These boilers were designed by engineer Yuri Blagodarov. Their main advantage is that there are non-volatile models. They do not use artificial air injection, the boiler runs on natural draft.
The thoughtful arrangement of fuel bunkers, afterburners and the use of a catalyst (bathing stone) made it possible to decompose not only simple carbons, but also complex ones. Due to this, the number of fuel types has expanded significantly, and the efficiency of its distillation has also increased.
Another distinguishing feature of these boilers is the ability to use raw firewood without losing power. Blago boilers of industrial capacities can operate on wood with 55% humidity, low-power units successfully cope with 35% humidity.
The design is constantly being improved. Recently, the production of equipment for burning used tires has been launched, there is specialized equipment that runs on coal.
Ordinary long-burning pyrolysis boilers "Blago" use firewood, sawdust, wood chips, trimmings and their mixture with coal chips. When using firewood, they, in principle, can not be chopped - whole small logs burn well.
As a result, boilers are truly omnivorous: they run on old tires, rubber, leather, polyethylene, not to mention traditional types of solid fuel.
Large pyrolysis boilers "Blago" have several fuel chambers (at least two). If necessary (small frosts on the street), you can put fuel in only one. The efficiency (81-92%) of the boiler does not change from this, only the power becomes lower. For example, a 50kW boiler can be used for 12kW. At the same time, for the period of acceleration of the system, it will produce 25 kW, and the rest of the time - 12-15 kW. There are small models (from 15 kW) with one fuel loading chamber.
Blago long-burning pyrolysis boilers with power from 12 kW to 58 kW are produced. More powerful installations are made to order with the coordination of input and output parameters. For units from 1 MW, an automatic fuel supply line can be developed (this is the data from the report of the author of the project).
What does the manufacturer guarantee besides “omnivorousness”? Firstly, a smaller amount of fuel required - it is needed by 20-30% compared to other boilers of the same operating principle. Secondly, long-term burning - the laying of fuel occurs every 12-18 hours. Thirdly, high safety: the loading door and the furnace valve are combined, which prevents accidental ignition during fuel loading, automatic adjustment of the plug is provided to prevent the release of gases in case of violation of the installation rules. Fourth, ease of use: automated control, no smoke when loading fuel, automatic cleaning of fuel channels.
Now about the shortcomings that are pointed out on the forums:
- The equipment is expensive.
Yes, it's not cheap. But everyone is sold a package of documentation for self-production.
Model | Power | Square | Maximum system volume | Dimensions, mm | Fuel | coolant | Price |
BLAGO-TT 15 | 15 kW | 150 m2 | 0.83 m 3 | 1200*530*970 | Firewood, wood waste | 48 tr. | |
BLAGO-TT 20 | 20 kW | 200 m2 | 0.60 m 3 | 1200*530*1140 | Firewood, wood waste | Water, non-freezing liquid for heating systems | 60 tr. |
BLAGO-TT 20 | 25 kW | 250 m2 | 0.75 m 3 | 1540*725*950 | Firewood, wood waste | Water, non-freezing liquid for heating systems | 75 tr. |
BLAGO-TT 30 | 30 kW | 300 m2 | 0.84 m 3 | 1540*725*110 | Firewood, wood waste | Water, non-freezing liquid for heating systems | 90 tr. |
BLAGO-T2 T-BH-40 | 40 kW | 400 m2 | 120 l | 2300*1100*1100 | Firewood, wood waste | Water, non-freezing liquid for heating systems | 120 tr. |
BLAGO-T2 T-BH-50 | 50 kW | 500 m2 | 168 l | 2300*1100*1300 | Firewood, wood waste | Water, non-freezing liquid for heating systems | 150t.r. |
BLAGO-T2T-BC-40 (built-in heat exchanger) | 40 kW | 400 m2 | 1805*1100*1100 | Firewood, wood waste | Water, non-freezing liquid for heating systems | 120t.r. | |
BLAGO-T2T-BC-48(built-in heat exchanger) | 48 kW | 480 m2 | 1805*1100*1300 | Firewood, wood waste | Water, non-freezing liquid for heating systems | 144t.r. |
- As a disadvantage indicate the rapid cooling of the boiler with a late laying of fuel.
- The boiler is difficult to pyrolysis.
But the last two shortcomings are the result of little experience with this boiler and the wrong position when kindling the ash pan. Some consumers do not like the excessive removal of the heat exchanger walls, which makes it difficult to load fuel (TTS and TTU models).
Czech Atmos
The Czech company Atmos (Atmos) manufactures more than 200 models of heating boilers that burn wood, diesel fuel, briquettes. There is equipment that runs on several types of fuel, gas boilers are made to order.
Atmos long-burning pyrolysis boilers are produced both for heating small rooms with a capacity of 15 kW (90-180 m2), and for industrial premises up to 1000 m2 and more.
They consist of two chambers located one above the other: at the top is a fuel chamber, at the bottom is a chamber for afterburning gases. The chambers (one or both) can have a ceramic finish, which increases the efficiency of heat use - it does not dissipate through the walls, but goes to heat the coolant. The fuel bunker is large, even fairly large logs can be laid there. This reduces power, but increases the duration of burning (can be used in warm weather, when high temperature in the system is not needed).
Atmos produces pyrolysis boilers for different fuels:
- on wood - marked Atmos DC;
- coal-wood - Atmos C and Atmos AC;
- pyrolysis boilers Atmos DC 24 RS, DC 30 RS;
- pellet boilers Atmos
The marking of the boilers also contains the prefixes GS, GSE and S. The first two types have an all-ceramic finish of both furnaces, due to which the efficiency becomes higher, and the percentage of carbon dioxide emissions into the atmosphere is much lower. Despite the fact that the cost of such devices is almost 50% higher, practically only equipment of this type is sold in Europe. In our country, the lion's share of sales falls on less efficient, but cheaper boilers marked S without ceramic coating of furnaces.
Atmos long burning pyrolysis boilers: prices and specifications (click on the picture to enlarge it)
German Bosch quality
Boilers from the German company Bosch can be used as the main or backup heating equipment. They are distinguished by a wide possibility of power regulation (by changing the operating mode of the smoke exhauster, you change the power of the thermal unit). The efficiency of the boilers is 78-85%, the volume of water in the system is 76-124 liters.
Technical characteristics of the pyrolysis boiler for long burning Bosch Solid 5000 W-2
Boilers work only on wood with a moisture content of up to 25%; briquettes made of wood materials can be used. The design of e is similar to Czech counterparts: on top there is a bunker for loading fuel and its gasification, and on the bottom there is a gas afterburner chamber. Between them is a ceramic burner. The cost of such boilers is from 2000 euros.
Another video material that explains the principle of operation of solid fuel pyrolysis boilers
Pyrolysis boilers with and without a water circuit are highly efficient equipment for high-quality and fast heating of premises. Advanced technologies underlying manufacturing, absolute safety, high heating speed and other advantages make these devices a separate group of modern heating devices that have already managed to occupy a worthy niche in the market, acquire a wide audience of fans and positive reviews.
The firewood laid in the boiler chamber gradually burns out and smolders. At the moment of insufficient oxygen, in addition to heat, smoke and a certain amount of combustible gases are formed. Unlike wood fuel, anthracite is almost entirely composed of carbon, which allows us to talk about a smaller heating effect and the release of only carbon monoxide. The composition of firewood is dominated by cellulose (carbohydrates) and contains a decent amount of water, so this type of fuel emits a wide variety of substances.
Comparison of the device of boilers
The combustion time of gases is minimal, and soot is practically not formed during the combustion process, which has a positive effect on the efficiency of the heater. To activate the gas evolution process, the boiler should be well heated. Most often, a special design is used for this. Despite the fact that gas-fired boilers are somewhat more expensive than conventional solid fuel models, these costs will more than pay off in the near future.
Device and principle of operation
The design of the boiler includes 2 chambers: the lower one is designed for pyrolysis, and the upper one is for combustion of gases released during the combustion process. Since all processes proceed under the influence of high temperatures, all elements and the boiler body must be made of heat-resistant materials. Most often, manufacturers resort to cast iron because of its super strength, good resistance to corrosion and temperature effects. Often there are also boilers made of steel, which heat up very quickly and also cool down quickly. Such designs provide for the presence of a special ceramic coating that protects the steel from burning through.
pyrolysis boiler
The principle of operation of the pyrolysis boiler is the process of generating pyrolysis gas from solid wood at a temperature regime from 200ºС to 800ºС and a lack of oxygen and subsequent afterburning of the released gases, which are mixed with secondary air already in the afterburner compartment.
For this:
- solid fuel resources are placed in the loading chamber;
- using the regulator, the combustion mode is selected and set, upon reaching which the boiler performs the functions of a furnace;
- after the combustion chamber is warm enough, the regulator switches to the pyrolysis mode. At this moment, air access is blocked, due to which the wood gradually smolders and the space is filled with a large amount of carbon dioxide;
Pyrolysis boiler with bottom chamber
- gas moves to the second chamber, which is usually located at the top of the boiler, but in some models it may be at the bottom;
- mixing with oxygen, the gaseous substance is burned, while an additional amount of heat is released, which heats the room.
Important! Since long-burning pyrolysis boilers with a domestic water circuit are modern and productive heating devices, they provide for the possibility of easy and effective control over the combustion process. In addition, they solve the problem of creating favorable conditions for the formation of the maximum amount of emitted gases and heat.
Fuel
Equally productive solid fuel boilers can operate on any solid fuel - it can be peat, coal (both black and brown), ordinary wood, fuel briquettes. Since all the mentioned raw materials have their own distinctive features and qualities, their complete combustion time is also excellent. For example, the burning time of soft wood is 5 hours, hardwood - 8 hours, and the burning time of coal reaches 10 hours.
Wood is one of the most affordable fuels.
In this regard, the opinion of experts is also curious: they all unanimously affirm the high performance of boilers operating on hard and dry wood. To achieve maximum performance, good heating of the room and long-term trouble-free operation of the equipment, it is recommended to use dry firewood, the length of which does not exceed 60 cm, and the humidity is 20%.
Important! The color of the pyrolysis gas is almost white, while no side substances should be formed during combustion. However, with excessively high humidity of solid fuel, the appearance of tar, soot, a sharp decrease in the calorific function of the equipment and even its spontaneous attenuation is not excluded.
Comparing wood and other solid fuel raw materials, which can only be used for the uninterrupted operation of a pyrolysis boiler, with gas, one can note the availability and environmental friendliness of the former, the high cost, and in some cases the impossibility of building a gas pipeline.
As for solid fuel, there is plenty of it in every Russian region, and its transportation will require only a highway and a capacious transport. For many rural residents, pyrolysis boilers operating on solid fuel resources are a real salvation.
Advantages of pyrolysis boilers
Before buying and installing such heating equipment, you should carefully identify and analyze all the pros and cons of a particular model or type of boiler.
The pyrolysis boiler is quite efficient and at the same time easy to operate.So, a long-burning pyrolysis boiler, compared to other heating devices, has a number of undeniable advantages:
- the fuel consumed is affordable and freely available;
- high efficiency when using firewood and fast heating of the room, regardless of its dimensions;
- high rate of heating of the coolant;
- long work with one loading cycle;
- affordable functionality and simple adjustment of the intensity of combustion;
- ease of maintenance;
- good stability of work and long, maintenance-free operation;
- ease of installation of the pyrolysis boiler, no need for laying and connecting the pipeline;
- heat loss is very small;
- easy cleaning of equipment due to the formation of a minimum amount of ash in the chamber and chimney during operation;
- the minimum volume of emissions allows not to pollute the environment.
Installed pyrolysis boiler
Pyrolysis boilers for long burning, unfortunately, are not without drawbacks. One of the main drawbacks is the price of the device. Regardless of the manufacturer and design features of pyrolysis boilers, they are all somewhat more expensive than other solid fuel appliances.
In addition, these boilers are single-circuit devices that are not designed to heat domestic water. Another drawback, which was already mentioned earlier, is the sensitivity of the equipment to the moisture content of wood: at high levels of humidity, the efficiency and efficiency of the device may decrease. It is impossible not to note the impressive size of the unit. And finally, the regulation of the intensity of combustion is possible only in manual mode, full automation is not provided.
Factors of efficiency of pyrolysis boilers
The performance of heating equipment, the efficiency and speed of heating the premises, in addition to fuel resources and their humidity, are also influenced by the following factors:
Choose a boiler depending on the characteristics of the room
- room temperature;
- the temperature level to be reached;
- presence (absence), as well as the quality of building insulation;
- specifics of the current heating system.
How to choose the right boiler
If you have the opportunity to buy inexpensively or prepare wood in advance, then you can safely and for a long time without doubting the high productivity of work, buy and install a long-burning pyrolysis boiler at home.
If you are not at all sure of this possibility, then we recommend paying attention to the boiler, the furnace of which combines 80% pyrolysis combustion of solid fuel resources and 20% conventional. These devices are considered combined, since they allow high-quality combustion of not only traditional firewood, but also wood and coal waste, peat waste, as well as any other fuel mixture, the moisture content of which will be less than 50%. Such a combined heating device is capable of burning about 80% of solid fuel in the pyrolysis mode, and the remaining 20% in the mode of the most ordinary boiler that runs on solid fuel resources.
Pyrolysis boiler device
When buying a boiler, be sure to visually evaluate the volume of the loading chamber. The best option would be a device whose loading capacity will be able to fit wood 65 cm long. The coating of the chambers is also important: the presence of ceramic concrete guarantees the integrity of the compartments at maximum heating, protects the walls from burning through and ensures the necessary combustion of raw materials.
Attention! Familiarize yourself with the technical characteristics of the equipment you like. Pay special attention to the indicator of the duration of combustion of fuel resources: the average duration of combustion should not be less than 10 hours.
Pyrolysis boiler operation: video
Choosing a boiler is a very complex and controversial task. In search of the optimal solution, many pay attention to pyrolysis structures. But they cannot be considered as some kind of universal solution suitable for all cases. It is necessary to carefully understand their features with specific examples.
Device and purpose
A pyrolysis boiler for heating a private house works by burning fuel at a very high temperature and with limited air access. Instead of solid fuel, a new one is actually created - a special gas. It is additionally burned in a special chamber, which is usually located below the solid material intended for backfilling. Accordingly, the air is pumped first into the upper part, and from there it enters the lower chamber. Since this is contrary to the laws of physics, they have to be overcome artificially, using fans or pumps.
The lack of oxygen in the air used helps to make combustion more protracted than in conventional boilers or furnaces. It is possible to extend the time of heat transfer from one portion of firewood, for example, up to 20 hours. Miracles, of course, do not happen: they give off thermal energy in small portions. But for a greenhouse, such a solution turns out to be even a plus, because it allows you to maintain a stable temperature without overheating and hypothermia.
Since only automation can set the modes and switch them in time, the most advanced designs cannot be cheap; however, the opportunities are worth it.
The use of a pyrolysis boiler for a bath deserves a separate discussion. It turns out to be more practical than both gas and electric heaters. In terms of efficiency and convenience, it is ahead of many stoves, especially when compared with home-made designs. Any pyrolysis boiler has a horizontal segment (the so-called "hog"), which is designed to connect the structure to the chimney. The wall thickness in this place is 4.5 mm, and the usual length reaches 50 cm.
The characteristics of the pyrolysis boiler allow us to consider the increased (in comparison with simple solid fuel alternatives) cost quite appropriate in most cases. The time of use of one load of fuel is difficult to predict in advance, it depends on a large number of factors. In technical documentation and popular descriptions, the minimum and maximum possible numbers are usually given.
They are affected by:
- humidity of the used fuel;
- temperature in the house and on the street;
- quality of insulation;
- features of the heating system.
Dry distillation is controlled by a nozzle that doses the intake of atmospheric air. Importantly, boilers operating on the principle of pyrolysis are able to dry the stocks of firewood or coal stored in the same room. Features of the operating mode exclude the ingress of not only carbon monoxide or carbon dioxide into the living quarters, but also safer water vapor. Most designs work best with very well dried wood.
It is for her that the design indicators of the maximum power and the combustion period are calculated.
Principle of operation
Pyrolysis boilers compare favorably with simpler solid fuel devices with increased efficiency. As well as ensuring long burning, this effect is caused by the peculiarities of the working process. Pyrolysis begins with the ignition of the wood, which must be well engulfed in flames. This is achieved by the maximum opening of the throttle and blower. The firebox is filled to a certain level with firewood, they are supplemented with a small torch.
As soon as a stable flame appears, the boiler is ready for full operation. To do this, the throttle valve and the blower are blocked and the automation is started.
It doesn't matter if the system is running at some point on natural draft or if the fan is running. This does not change the essence of physical and chemical processes. As soon as the access of oxygen is limited, smoldering coals remain instead of a strong fire. But not for long: automatic systems almost immediately give the command to start the fan.
It does not fan the fire, but moves the gaseous products of pyrolysis to another chamber; there is a fire burning.
The only difference is that both simple mechanical devices and electronics can take control of all these actions. Inside the main firebox, the temperature can reach "only" 500 degrees. But in the pyrolysis compartment, this figure rises to 1100 and even up to 1200 degrees. The closer to the top of the torch, the higher the temperature will be. It is curious that the exhaust gases in such a boiler, on the contrary, are colder than usual.
It is important to consider that the fuel loading mode has its own characteristics. The forward stroke damper is unlocked, but for some time the draft in the chimney still remains. If there is a fan, the system will not stop its operation. And this means that pyrolysis will continue even at this very moment.
Since there is a rapid movement of hot gases in the working chamber, only the strongest materials are used.
Pros and cons
It is not enough to study the reviews of owners and specialists on specific models, to get acquainted with the ratings of the best modifications. It is also necessary to answer the most important question: how do the advantages and disadvantages of pyrolysis boilers compare, do they actually justify the investment. And here there can be no universal answer, because a lot depends on priorities and on the peculiarities of using the equipment.
When the firewood runs out, the ash pan and gas passages are almost not covered with soot.
Any pyrolysis boiler, by virtue of its design features, has built-in automation. Working for many hours on one gas station frees up a lot of time and effort. As a fuel, almost any waste processing and harvesting of wood, and sometimes not only them, can be used.
The flip side of these benefits are:
- attachment to the operation of the power grid;
- mandatory installation of uninterruptible power supplies;
- unsuitability of raw wood;
- the inability to supply water to the heating circuit colder than 60 degrees (it forces corrosion);
- the inability to automate the loading of fuel itself (feeding from the bunker only makes manual work less common, but does not completely exclude it);
- the need for lining with fireclay bricks;
- increased cost compared to simple solid propellant devices.
Fuel types
Talking about pyrolysis boilers "in general" is useful, but it is equally important to understand what kind of fuel they can use. They can be fired with almost all types of fuel that are available in the private sector. Wood-fired boilers do not use any logs, of course, but only those whose length does not exceed 0.4 m. Heat transfer is decisive when choosing a suitable wood species.
Birch burns quite hot, but with a lack of air it can produce a certain amount of tar.
Coniferous wood behaves in much the same way. Oak firewood is the most "energetic", but the cost of their use is excessively high. Aspen and alder firewood produce the least soot, therefore they are used mainly for cleaning chimneys. Most experts recommend the use of hardwoods, and those that contain little resin are best. Instead of the usual logs, the tree can also be presented in the pellet format.
For their production, by-products of the agricultural and forestry industries, as well as peat, are used. Processing at high pressure perfectly replaces gluing, so there is no point in fearing increased toxicity of pellets. Another modern modification of the old version is the so-called eurofirewood. They are made from the same raw materials as pellets, but briquettes in the form of a cylinder go under the press.
The length of the briquettes is slightly increased - up to 45 cm.
Coal-fired boilers are a significant alternative to wood burning ones. Mineral fuel, like forest fuel, is used in two stages: initially it emits volatile gases, and then solid coke mass burns in the afterburner. Lignite coal burns out on average in 8 hours, when using anthracite, the time between refueling increases already up to 10 hours. Sawdust boilers are quite widespread, which are inexpensive and do not pose any environmental threat. The supply of sawdust is now arranged in a convenient compact package, from which nothing should spill out.
But besides these advantages, they also have a disadvantage - a small amount of heat and rapid combustion compared to other solids. Some of the boilers run on waste oil, which makes it possible to achieve an efficiency of up to 94%. 1 liter of mining gives up to 11 kW of thermal energy. After cleaning to the level of heating oil, the return increases by about 25%. More accurate data cannot be given without analyzing the type of boiler, operating mode and the nuances of the chemical composition of the used oil.
In addition to the purely technical characteristics of the fuel, it is necessary to take into account their practical properties. So, coal burns hotter than many other types of fuel and emits a minimum of harmful substances. With its help, it is easy to extend the pyrolysis process - already longer than classic combustion. Pine wood is not suitable for firing solid fuel boilers. When using its working chambers get dirty very quickly.
It is impossible to use sawdust and shavings that have not been pressed. They contradict the very essence of a solid fuel boiler. In terms of market value, the undisputed leaders are pellets and special granules. But we must not forget that pellet and coal boilers operate with less power than wood or combined types.
It is not necessary to lay chips shorter than 70-100 mm inside (the exact border depends on the model).
Overview of models and manufacturers
Pyrolysis boilers are being made in Russia, and quite successfully. Popov's constructions are a vivid example of this. Experts believe that such a scheme is one of the most economical at the moment. On the territory of our country, Popov's boilers are also good because they do not depend on electricity, the control is carried out by mechanics. At the same time, even in the most remote areas or with unstable power supply, you can adjust the temperature with an error of 0.5 degrees.
Importantly, the system can be stopped at any convenient moment, and ash removal is possible even during operation.
Popov's boilers are used in:
- greenhouses;
- warehouses of agricultural products;
- country houses and country houses;
- baths and saunas;
- emergency heating systems.
Poor quality wet wood is allowed (which attracts the attention of sawmills and woodworking enterprises). However, the thermal efficiency of such fuel is 50% less. It is possible to increase the power only after the final evaporation of the water contained in the wood. The temperature of the exhausted gases is limited to 140 degrees. Important: the critical humidity for the fuel used in Popov's boilers will be 65%.
Tokarev boilers invariably occupy significant positions in various ratings. The power of such equipment varies from 15 to 100 kW. It is equipped with automatic systems that allow you to maintain a strictly specified heating for as long as possible. You can lay any tree, even waste from the production of furniture or peat briquettes.
The Tokarev system successfully copes with the heating of residential and industrial premises for 8-12 hours per tab, has an efficiency of 90%.
"Bourgeois-K" allows you to use not only water for heating, but also antifreeze. The company has developed three main versions: manual adjustment, automatic adjustment, automatic adjustment and hot water circuit. The efficiency of any version is 85%, the mass of the structure ranges from 180 to 900 kg, the liquid is heated up to 90 degrees. The gases coming out are heated up to 150 degrees. Installation of pipes from 7 to 13 m is required, chimneys with an internal section of 0.15-0.25 m communicate with them.
Boilers "Bourgeois-K" are equipped with carefully thought-out thermal protection, for which mineral wool is used. Any components of the apparatus are made of a special kind of steel, carefully tested for resistance to heat and corrosion. Specially developed powder coating reliably stops moisture, salts and acids. Of course, it does not suffer from significant temperature and is resistant to mechanical abrasion. Mechanical adjustment makes it possible to almost eliminate the risk of excessive heating.
The manufacturer declares that it is impossible to put chimneys with horizontal sections to his boilers.
Relatively good boilers are also supplied by Trajan. Model TR-50-1KT allows you to heat rooms with a total size of up to 520 square meters. m. Traction control is carried out by an automatic device; a heating element can be additionally connected. The hot water supply pipes to the system must be 1 ½" typical diameter. The number "50" in the index of the model indicates the thermal power, and the efficiency is 92%.
TB-10-2KT is a double-circuit device. An additional heating element can be connected to it. The power of the connected electric heater is 3 kW. The boiler itself produces 10 kW and provides an efficiency of 85%. The mass of the device is 190 kg, it can work with chimneys with a cross section of 150 mm and a height of 7 m; a two-pipe heating scheme is preferred.
Trayan provides a full factory warranty for 30 months from the date of purchase. The chimney must have a diameter of 0.2 m. It is recommended to use the boiler in a two-pipe heating system. The choice of water or antifreeze as a coolant is left to the discretion of the owners.
But for normal operation with antifreeze, artificial circulation is required.
Buderus products show excellent results. The pyrolysis boiler S121-2-21 can heat up to 180 m2, it is allowed to connect a heating tank for the water circuit. The total thermal power reaches 21 kW, and the size of the loading chamber allows you to enter logs up to 0.58 m long. The body is made of steel, the system is designed with the expectation of both gravity and pump circulation. The ash compartment is formed from fireclay.
The designers took care of safety: if the door opens, the smoke will be completely stopped by a special smoke exhauster that starts automatically. Warranty service is provided for 2 years after the boilers are put into operation. Atmos equipment is manufactured in the Czech Republic, and this brand has become one of the leaders in the European market for solid fuel systems. 4 out of 5 boilers of the Czech manufacturer go abroad, including to industrialized countries with strict technical control. Wood-burning gas generators produce up to 100 kW of heat, combined ones (allowing the use of coal as well) are limited to 50 kW.
If record power is not required, you should pay attention to Atmos AC, which consume only hard coal and produce from 20 to 26 kW. The Russian competitor, Divo, supplies boilers capable of heating from 120 to 750 sq. m. "Divo-10" provides a thermal power of 8-12 kW, consuming no more than 2.1 cubic meters. m tree per month. The maximum log length is 49 cm, the boiler itself “pulls” 130 kg. "Divo-12U" is more economical with the same power, consumes up to 1.5 cubic meters. m of firewood, it is possible to connect a heating element.
The manufacturer claims that the double afterburning of pyrolysis gas increases the efficiency up to 92%, and that the boiler will pay off by the end of the third heating season.
Allowed use:
- wood production waste;
- briquettes;
- brown coal;
- anthracite of various sizes;
- peat.
German products have been confirming their quality for one and a half hundred years. The Viessmann brand is also trying to maintain the high prestige of the national industry. The Vitoligno 100 S pyrolysis boiler is equipped with a Vitotronic controller. Automation coordinates not only the power of heating and ventilation of the furnace; it helps to find out what problems have arisen and whether additional fuel needs to be loaded. The series includes five different modifications, the power of which ranges from 25 to 80 kW. The combustion chamber can hold 100-350 liters, the maximum length of logs is in any case limited to 0.5 m.
If the firewood used is dry enough and the boiler is set up correctly, you can count on an efficiency of 87%. It is recommended to use fuel with a maximum moisture content of 20%. Under the Geyser brand, household, industrial and semi-industrial pyrolysis-type boilers are sold. In the domestic segment, the company presents devices with a capacity of 10 to 30 kW. The PC Economy-10 system, thanks to a carefully designed water jacket, can withstand pressure up to 10 atm, which guarantees the safety of using the boiler.
In standard rooms (with a ceiling height of up to 3 m), it will provide heat for 100 square meters. m. It takes a little more than 2 cubic meters per month. m quality firewood. The option of connection of TEN is provided. Grids and gate are delivered together with a copper. Placement in an isolated space is not required.
The design of the PK-100 will help to heat up to 1000 square meters. m, the water tank holds 100 liters of liquid. The recommended diameter of the chimney is 25 cm. In a month, a powerful device will burn up to 10.8 cubic meters. m dry firewood. One-time capacity of the furnace - 0.65 cubic meters. m.
The manufacturer guarantees the comfort, simplicity and safety of using the device.
Ukrainian company "Motor Sich" specializes in the production of aircraft engines, but it also suits pyrolysis boilers quite professionally. For engineers focused on such a complex production, they do not represent the slightest problem. Attention should be paid primarily to such modifications as "MS-16" and "MS-25". They are able to take a fresh saw cut of a tree even at a humidity of 50%. To warm a house of 100 sq. m, you will need to spend about 30 kg of wood in 24 hours.
The well-thought-out design is very stable and allows installation even under outdoor sheds. The time from one load to another is 8-15 hours, that is, continuous supervision of the boiler is not required. The outer walls are from 0.6 to 1 cm thick, they are immune to the harmful effects of the resin, they almost do not burn through. Such attractive qualities are achieved through the use of refractory ceramic concrete.
The air-drawing mechanism and controller are made in the EU, fully comply with the latest standards.
Criterias of choice
Choosing a model is not all that is required to make the right decision. A heating boiler with a water circuit is good because it reliably heats even large houses and minimizes effort. Water heating is smoother than when using air convection, the distribution of energy becomes more even. The increased thermal capacity of water compared to air is also a plus. Yes, it warms up worse, but it retains the already received heat better and allows you to pay a little less attention to new fuel fillings.
Air boilers will be better if it is impossible to ensure constant control over them. They are also preferred for intermittent heating, when the heating circuits cool down from time to time. Non-volatile boilers help not to be afraid of a sudden power outage or to heat houses where it does not exist and it is not clear when it will appear. Eliminating the pump makes the system less noisy; but there is no full confidence in the stability of heating under any conditions. Natural circulation forces you to buy larger pipes, which are more expensive, heavier and take up a lot of space.
It is also worth remembering that without forced circulation it is impossible to heat houses with a height of more than one floor. At the slightest violation of thrust, the combustion efficiency is sharply reduced. As for shaft-type boilers, they are almost always combined and can even be called universal, as they are able to absorb a wide variety of fuels. Bookmarking it is spent more economically than in other schemes.
It is possible to clean the space under the firebox from ash directly during operation, without stopping the heating.
We must not forget that the correct piping is critical for a mine boiler. Violations during its implementation are immediately recalled by loss of productivity and loss of valuable characteristics. In addition, the simplicity of the device does not mean that it will be easy to make such equipment in artisanal conditions. Yes, such a task is in principle feasible. Only with the greatest care and careful calculation.
Boilers with a cast-iron firebox are characterized by increased thermal inertia and are poorly regulated. It will take a long time for the system to warm up or cool down, and even the automatic regulator will not allow you to correct the situation. Moreover, heating will respond to changes in the environment slowly, and therefore additional inconvenience will be created. Loading cold firewood or filling the tank with cold water is strictly unacceptable.
You can insure yourself by using submix nodes.
The power of the pyrolysis boiler deserves a separate discussion. It is impossible to understand exactly whether 20 kW is enough, or whether this indicator is excessive, if you focus only on the area of \u200b\u200bthe house. The best source of information is a project prepared by experienced architects who will indicate all the necessary parameters.
Consideration should be given to:
- building height;
- the presence of heated or unheated attics, basements, adjoining outbuildings;
- number of windows and their sizes;
- the number of chambers in each double-glazed window;
- perfection of thermal insulation;
- average annual and maximum possible wind speed;
- insolation;
- air humidity in a particular area.
How to do it yourself?
Making a pyrolysis boiler with your own hands is quite possible, you just need to draw up detailed drawings of a home-made apparatus, carry out a comprehensive calculation and prepare a connection diagram. The combustion chambers are separated by a grate, solid fuel and its residues are burned at the bottom, and gases obtained during pyrolysis are burned at the top. In industrial conditions, other designs are also used, but for amateur craftsmen it is better to choose the simplest solution. Finished branded products cost at least 36 thousand rubles, while they can only heat up to 100 square meters. m.
Do-it-yourself work will cost about 25-30% cheaper.
For this you will need:
- welding machine with 3 or 4 electrode packages;
- small angle grinder;
- electric drill;
- pipes with a diameter of 5.7 cm with a wall thickness of 0.35 cm;
- pipes with a diameter of 15.9 cm, thickness - 0.45 cm.
- tubular profile 3x6 cm, wall 0.2 cm;
- tubular profile 4x8 cm, wall 0.2 cm;
- steel strips;
- iron sheets;
- chamotte.
Whenever possible, it is worth creating a 3D sketch of the internal equipment, then the presentation will become clearer, the work will be simplified. Important: cutting metal with a grinder cannot give a sufficiently even cut. The payment for cutting it with a guillotine, including when building a boiler from a cylinder, is absolutely necessary and justified. After assembling the chambers, air outlets and walls are welded to them from behind. It is convenient to make a smoke channel from a channel, but no one forbids using a profile pipe; It is only necessary to prepare holes for ventilation in it.
The next step is to form a hole for the air pipe and weld the pipe. To connect this pipe with the boiler, a 2x2 cm profile of a tubular section is used. The heat exchanger is formed from a profile of 5.7 cm - it must be cut into homogeneous fragments, put on a plate and attached around the perimeter by welding. Then the heat exchanger itself is welded to the boiler and the throttle valve is prepared. It is time to weld the front wall, but it should already have openings for air inlet and outlet.
The assembly continues by welding the cover and the hog, only after that the inside of the boiler is assembled. For your information: at this stage, it is already possible to level the places that have been welded with the help of an angle grinder, a file or a metal brush. The fastening of the casing with the corners is achieved using small holes that are welded. Next comes the turn of the tightness test, during which the boiler is filled with water for the first time. The cover placed on top must be insulated; air dampers are controlled by threaded studs.
When the boiler is completely closed, mount the hinges and the door (preferably cast iron); brick lining is recommended. Important: the downstream chamber should also be lined; for this, refractory material is used. It is cut and grinded for the tightest pressing of the camera. It is necessary to pay attention to the exact correspondence of the dimensions of the damper to the requirements of the project.
The air duct from the profile pipe is supplemented with a blower fan.
Turbine devices that create vortices help to increase the efficiency of the boiler. They not only make heat transfer better, but also help to clean pipes from various blockages. Before the final start-up of the device, you should once again check the tightness of the seams. Now the water is supplied at a pressure of 3 or 4 bar. A special apparatus - a crimping machine - will help to create it.
In order for the boiler to work properly later, it must be equipped with a safety group - at least a pressure gauge, a pressure relief device and an air outlet. The system is set to self-reset when the pressure exceeds 3 bar. Attention: it is impossible to arrange any tests for empty boilers, especially in the absence of a thermometer. Checking involves laying out paper and 2 or 3 logs.
It is necessary to set fire to the paper with the chamber tightly closed and with the throttle door open.
As soon as the whole tree is on fire, the damper is closed to start the much-needed pyrolysis. Watch from below when the torch appears. Immediately after this, the time until the coolant boils is counted. When it happens, turn off the fan and thereby extinguish the torch. Only the flawless passage of all stages of such a test allows the use of a home-made boiler for heating.
Experts believe that it is best to use cast iron grates for the pyrolysis boiler. Instead of a cylinder, an unnecessary steel safe can serve as a good blank. There, the steel is quite strong and reliably protected from destruction at high temperatures. Adding a contour of pipes will help to increase the heat transfer area. A refractory brick is placed at the bottom to improve the penetration of air in the corners.
Installation
Quite a lot of people do not have sufficient knowledge and do not have special tools, skills in handling them. But even the absence of a welding machine and the ability to use it is not scary. Step-by-step instructions for installing and tying a finished pyrolysis boiler will help fix the issue. Knowing it is useful, of course, when using self-made equipment. It’s worth clarifying right away that simplicity or functionality is of decisive importance when choosing a connection scheme.
Thus, the most advanced options allow the use of heat-accumulating containers that help maintain a stable temperature for up to 48 hours even when the boiler is not working.
Before installation, you should purchase specially selected:
- fitting;
- pipes;
- bends;
- filters;
- check valves and other devices.
Experts believe that the best circulation pumps are German-made. Although they are a little more expensive than models from other countries, the durability and increased performance justify the difference. But you can choose the manufacturer of other components at your discretion. Since inside the pyrolysis boiler there are circuits with very strong heating, as in metallurgy, fire safety standards must be scrupulously observed. The boiler room should be placed in a separate room.
Normal ventilation will only be achieved through a 100 sq. see. It is required to put the boiler exclusively on concrete or brickwork. The space in front of the chambers is closed with a steel sheet measuring 1x1 m and at least 0.2 cm thick. It is unacceptable to mount the boiler where firewood is stored. The elevation of the chimney above the roof must be at least 0.4 m, and it is forbidden to install leaky structures to remove smoke.
The minimum approach to walls, even made of non-combustible materials, is 0.7 m. It is advisable to set the boiler according to the level, since the slightest tilt to the side will have a bad effect on its characteristics. Connoisseurs and experts recommend insulating the chimney from the inside. This helps to accurately avoid the occurrence of condensation and the associated negative phenomena. All these tips can be implemented without resorting to specialists, that is, at minimal cost.
The chimney pipe must reach a height that maintains the desired draft. The minimum value is 50 cm above the ridge of the tallest building located within a radius of 10 m. It is not allowed to install chimneys whose diameter differs from the diameter of the dampers or gas flow chokes. After these gates, a straight vertical line with a length of 2 m or more should be mounted, only in the next section it is possible to turn 45 degrees, and strictly up to 100 cm.
Insulation is mandatory for all sections of the chimney that are raised above the throttle, regardless of whether they are placed in the room or outside the house.
For modular chimneys, “condensate” assembly is practiced, when the upper elbows are inserted into the lower segments. It is impossible for the chimneys to put even a little pressure on the gates. From the top line of the head to the top of the pipe, a gap of at least 15 cm is left. Thermometers are placed strictly on the return lines of the heating systems, at least 1 m from the boiler. It is advisable to use a thermometer with scale markings up to 120 degrees.
It is better to form the initial section (1 m of the outlet for the coolant) and the same segment at the beginning of the return stroke from metal. The first turns are made in the format of half-bends. You can not use right angle turns instead. In general, it is recommended to reduce the number of turns. There must be at least 2 m of free space between the front part of the boiler and fences or walls.
Service
The tightness of the boiler itself, pipes and chimney should be checked regularly, at least before the start of each heating season and after its end. For ignition it is required to use only dry wood, the bookmark is made with paper up to the opening for primary ventilation. Service work is reduced to the removal of ash and ash from the working chambers. The heat exchanger should also be occasionally emptied of solid combustion products.
The frequency of cleaning it is determined by:
- type (energy value) of fuel;
- its level of humidity;
- resin concentration.
Remove soot and soot should be carefully, for this special blades are provided. Even if they are not included, the manufacturer indicates the recommended devices in the technical documentation. It is important to control the tightness of the loading and pyrolysis chambers. When the packing of the seal sits, the doors are pulled tighter or the seal itself is changed. The lining is replaced by oneself only if it is allowed according to the instructions and only with recommended materials.
In the absence of clear instructions, it is advisable to consult the manufacturer's specialists. It is not allowed to fire pyrolysis boilers in the direct burning mode for more than 12 hours in a row and during the day; all manufacturers, without exception, refuse to replace burned-out partitions. The primary mode is intended strictly for the initiation of the pyrolysis process. It is impossible to extinguish firewood or coal with water, only sand is used. But this is also an extreme case, it is recommended to limit yourself to turning the gates (chokes) with the doors closed.
Boilers should not be fired with the doors open, except for igniting small chips. The front technical window should not open during the operation of the pyrolysis plant. If it is required to visually check for possible contamination, use a window in the back of the gas passage. If it is necessary to repair the boiler, locksmiths with welding equipment and the necessary skills should be invited.
Experienced specialists will choose the welding mode themselves without additional instructions.
You can learn how to make a pyrolysis boiler with your own hands from the video below.
What is a pyrolysis boiler. Advantages and disadvantages. Types of boilers. Specifications. Operating principle. fuel requirements.
Before buying a pyrolysis boiler for high-quality heating, you need to know in advance its features. This article describes in detail the principle of its operation. Advantages and disadvantages. Fuel used. Boiler design feature. Specifications.
How to choose the right boiler Equipment with a lower afterburner chamber and devices with an upper chamber. Basic principles of operation of the pyrolysis boiler. What is the essence of pyrolysis. Boiler types.
Features of pyrolysis boilers
Heating houses with solid fuel boilers is quite a common occurrence in small towns where there is still no gas. In most cases, the most common firewood or fuel briquettes are used as fuel.
The disadvantage of such boilers is that they are forced to make many approaches to throw up more and more new portions of fuel. Long-burning pyrolysis boilers are deprived not only of this drawback, but also of some others - we will talk about this as part of our review.
Traditional wood-fired boilers are annoying because they require constant supervision. That is, every 2-3 hours they need to put more and more portions of fuel in them, otherwise the pipes in the house will become cold. It is especially difficult at night, when instead of a restful sleep, households get a headache in the form of a cooling heating. On the one hand, sleeping in a cool place is good for health. On the other hand, meeting the morning, desperately chattering your teeth, is not very pleasant.
Expert opinion
Filimonov Evgeny
Ask an expertClassic boilers for home heating have another important drawback - low efficiency. The fuel in them burns very quickly, most of the heat simply escapes into the atmosphere.
Together with it, combustion products containing combustible gases fly into the air. They can be used to obtain additional portions of heat - this is what happens in pyrolysis boilers for long-term combustion.
As you already understood, solid fuel pyrolysis heating boilers are devoid of both of the above disadvantages. They are endowed with capacious fireboxes, burning solid fuel according to a slightly different principle.
Here are their main features:
- Large volume of the furnace - up to several tens of liters. Due to this, the frequency of approaches for laying fuel is reduced several times;
- The pyrolysis principle of combustion - allows you to get much more thermal energy from the same amount of firewood;
- Quite large - in fact, there are two fireboxes. In one, firewood slowly burns out, and in the second, the products of combustion released from the wood are burned;
- Low combustion temperature - reduces the thermal load on the metal.
Long-burning pyrolysis boilers are somewhat more complex than their traditional counterparts, but they provide significant fuel savings.
Operating principle
How does a long-burning pyrolysis boiler work and how does it work. The principle of operation is very simple and complex at the same time. Pyrolysis is described in the school physics course - being heated in a confined space, wood emits combustible gases that can be ignited and heat generated. In fact, there is no direct combustion of wood in such an experiment.
In long-burning pyrolysis boilers, firewood still burns, but with limited air supply. We can say that this is a slow smoldering. Having flared up, the tree begins to emit combustible gases that burn in the afterburner. In total, we get two sources of heat - these are burning wood and burning wood gas. The effect of such staged combustion is felt in the form of fuel savings of up to 40%.
Wood gas in pyrolysis boilers for long-term combustion is formed as a result of slow smoldering of fuel. At the same time, the equipment heats the air, which, together with wood gas, is fed into the afterburner. There, the mixture ignites and burns with the formation of a large amount of heat. At the same time, the amount of harmful emissions, in comparison with traditional boilers, is extremely small.
Thus, a pyrolysis boiler is a direct fuel saving, since more heat can be released from the same portion of firewood. Instead of 10 cubic meters of firewood for one winter period, only 6-7 cubic meters can be used. At the same time, users will not need to put all new portions of firewood into the insatiable firebox every 2-3 hours.
Long-burning pyrolysis boilers are available in several modifications:
- Non-volatile - they operate on natural traction and are mechanically controlled;
- Volatile - here the pyrolysis proceeds using forced draft. This increases the efficiency of combustion;
- With a different arrangement of the afterburning chamber - it can be located above the combustion chamber or below it. Also on sale there are modifications with a sequential arrangement of cameras.
There are many modifications, but in general, the device and the principle of operation are almost the same
Long-burning volatile pyrolysis boilers are good because they often have automation that can control the power of the equipment and the intensity of combustion, focusing on the temperature of the coolant or the temperature in the rooms.
Long-term combustion in pyrolysis boilers is ensured by two factors at once. The first factor is the low burning/smoldering rate of wood. The second factor is the large volume of the combustion chamber. For example, pyrolysis boilers with a furnace volume of 50 liters and even more are on sale. It is not surprising that the frequency of approaches for loading fuel is reduced to 1-2 times a day.
Advantages and disadvantages
Pyrolysis boilers have a number of advantages over their traditional counterparts.
But they also have some disadvantages.
Let's discuss all their pros and cons:
- Profitability - it varies from 10 to 40%, depending on the model, intensity of combustion and air temperature outside the window;
- Long burning - you can lay fuel only 1-2 times a day. For example, morning and evening. At any time of the day, the house will be warm;
- Ecological cleanliness - firewood burns almost completely, with minimal emission of combustion products;
- Almost complete heat transfer to the heating system - the temperature of the exhaust gases here is lower than in traditional boilers;
- In long-burning pyrolysis boilers, various power control mechanisms are often implemented - they work by adjusting the intensity of fuel smoldering and gas supply to the afterburner.
There are also disadvantages:
- High cost - user reviews say that long-burning pyrolysis boilers are very convenient, economical and practical. But the initial costs for their purchase are extremely high (most true for powerful volatile models);
- Energy dependence - such units are more efficient, but require connection to the mains (the total electricity consumption is small, but in its absence, work will be difficult or impossible at all);
- Large dimensions - long-burning pyrolysis boilers are noticeably larger than any other solid fuel units.
The disadvantages are not the most serious, some of them can be neglected. But you have to put up with the high cost.
Owner reviews of long-burning pyrolysis boilers in most cases are positive. People only complain about the tedious initial warm-up procedure, but here it's all about experience and habit.
Fuel used
We have already said that long-burning pyrolysis boilers run on wood. This is a fairly common and inexpensive type of fuel. In some cases, firewood can be obtained completely free of charge. But these boilers can operate on many other types of solid fuels. For example, in some stores we can buy a pellet pyrolysis boiler. It works on fuel pellets on the same principle as the above units.
Expert opinion
Filimonov Evgeny
Professional builder. 20 years of experience
Ask an expertThe main advantages of pellet models are automated fuel supply (implemented in some units), low ash content of fuel.
You can also purchase a pyrolysis boiler on coal. It will please you with long burning and high efficiency. Coal-fired boilers work on the same principle of operation, generating combustible gas from coal. Due to the powerful calorific value, the frequency of approaches for laying fuel is lower than when using long-burning wood-fired pyrolysis boilers.
Popov's boiler
Popov's pyrolysis boiler is a simple non-volatile unit made of steel. The design turned out to be so successful that many craftsmen copy it, assembling heating equipment with their own hands. The presented boiler is omnivorous, it can burn almost any solid fuel. And an impressive furnace of gigantic volume allows you to count on almost 24 hours of continuous burning. At the same time, the fuel burns almost completely, forming a minimum of components harmful to nature.
One of the advantages of this pyrolysis boiler is the ability to lay logs of non-standard size (up to 75 cm in low-power models up to 240 cm in the most productive units), which ensures long-term burning. The maximum power of the equipment is 1000 kW, the minimum is only 25 kW. Depending on the selected operating mode, the efficiency of the device varies from 75 to 95%.