As an optimal heat source for large production facilities, large apartment houses several apartments, can be considered boilers. This technique has changed little over time in terms of design. The reason for this, high reliability and performance. To this day, not only survived, but also continue to work even in enterprises and small boilers Boilers for solid fuel boilers, issued more than 30 years ago, even in Soviet times.
Use solid fuel, coal or wood for the organization of hot water and heating has always been cost effective. Especially when it comes to heating large industrial areas and residential buildings. The main argument in favor of the boiler equipment of this type is the high fuel savings. Comparing with the work of the gas equipment, heat generated boiler 5-7 times cheaper. In relation to the operation of the electric boiler, saving even more obvious.
Consider what a boiler is, what are the main differences it from heating equipment other types of solid fuel.
General information about this type of heating heating equipment
Fundamentally boiler does not differ from that of another heating device that heats the coolant by thermal energy. In the furnace there is virtually any organic or fossil fuels and various billing solid fractions. Firewood, charcoal, briquettes, all well lit and has a constant volume, there is a fuel for boilers of this kind.
Typically, such units are put in places where there is a constant and large quantities of a particular type of fuel. On the wood processing enterprises are boilers fired with wood and wood waste. In small boilers used for heating devices coal and lignite. Rarely in the furnace are made of peat briquettes, pellets. The maximum possible heat effect is achieved by using enriched ore anthracite or coke. For such a heating equipment, which are the boilers, is characterized by a high heat transfer effect. Due to the large screen surface of the heat exchanger can be reduced to the required large amounts of water temperature.
For instance: 1 kg grade coal "anthracite" during combustion releases at combustion in the furnace of the boiler to 7.16 kW of heat energy. Dry wood hardwood emit only 2.78 kW.
Despite the fact that boilers for solid fuels in comparison with gas boilers have low efficiency (of 78% on carbon and 70% on the wood), the economic costs spent for heating large quantities of water in such a fashion quite justified.
Other types of solid fuel units have a limited load. Water aids on the contrary, have a large supply of power, capable of operating at a constant high load. The largest effect of heat is achieved by using a large number of design of heat exchange elements, through which the heating boiler for heating water and hot water. The principle of operation of heating equipment of this type differs from that of other heating devices for solid fuels.
fundamental differences
Hot water appliance, in the simplest version - a heating boiler in which solid fuel due to the combustion heat medium is heated to the highest possible temperatures (95-1150FROM). At the time of operation of the heater in the water heat exchanger arrangement is under a pressure which is 0.6 MPa. Herein lies the principal difference of this type of boiler other heating equipment, where the heating medium in the boiler is first, and then the heating system circulates freely.
On a note: Typically, hot water boilers as a coolant, ordinary water is used, which is added for greater workability certain additives and impurities. Such measures are necessary in order that would extend the life of the main structural element - hot water circuit (complex system of water tubes in which the heat carrier takes place and heat).
When the water temperature close to boiling, begins intensive deposition (scum) on the vessel walls impurities dissolved in the water. Boil water boiler in this case is fundamentally not acceptable. Due to the fact that the heating water to high temperatures is carried out under pressure, boiling does not occur. The water pressure in the water circuit all points higher than the water pressure in the areas of maximum heating should be remembered that boiler water quantity necessary for heating the heating water boilers significantly larger than in conventional systems.
Heated to a temperature of 115 0With coolant transfers its heat to the heating system. The pressure in the piping system of the boiler is maintained at a constant level. The higher the pressure, the better. With increasing water pressure decreases the probability of boiling fluid in the boundary layer, respectively, is formed smaller scale and temperature of the liquid is equalized in all sectors of the heating circuit.
The combustion chamber in the boilers of this kind at all from our traditional ideas is no different. Solid fuels, mainly coal supplied to the furnace, where combustion. Through the wall of the combustion chamber thermal energy is transferred to the boiler water, which circulates through the heat exchanger. Each heating unit is designed in such a way that achieves a high intensity burning fuel and thus there is a maximum heat transfer. To reduce the temperature of the combustion products in the equipment provides convective packages. Due to its large surface the packages can reduce the flue gas temperature to 200 0FROM.
For reference: Lowering the temperature of the combustion products to lower values may cause condensation.
Design features of the boiler
Traditional assembly of this kind is a metal weldment in which there is required the support frame, the frame is equipped with thermal insulation, protective materials. The basic construction element, as mentioned previously, the system of hot-water pipes - the heat exchanger through which the boiler water circulation. coppers sheathed sheet metal outside.
The very design of the device and function suggests that these units are quite large sizes. In models of different types of combustors are calculated for various methods of loading and the fuel supply.
Ready fired solid fuel boiler plant assembly - is a single block in which all construction elements can be divided into two parts: a screen surface and convective. Surfaces made from solid-rolled steel pipe with a diameter of 76 mm. Between the pipes accommodate fins. This feature allows the heat exchanger design to minimize heat loss and reduce the leakage of hot gases through the unit housing. All elements are connected into a unitary structure by means of a weld joint capable of withstanding pressures up to 10 atm.
Important! All internal connections water heating circuit must only have a weld. The high temperatures and the availability of system pressure have specific requirements for welding works.
Loading coal or firewood is carried through heating unit that is equipped with conventional or rotary grate (for boilers with manual fuel supply). Under combustion part during installation of the boiler support frame in the lowermost part equipped with a duct through which the combustion chamber air mass will be injected.
Especially interesting is the cleaning heating equipment. The aggregates with manual feed of the removal of ash and soot through a special hatch. In motorized devices all similar processes are carried out by special mechanisms - conveyors.
Varieties boilers
As all solid-units, devices, and hot water boilers of the traditional type has its specific power settings. Model heaters, coal-fired powerful. Power range on different units in this case ranges:
- for low power equipment 4 kW - 65 MW;
- average power device 70 kW - 1.8 MW;
- boilers high power starting from 1.8 MW and above.
Units operating in the wood weaker than their "brothers coal." In this case, the power model boilers varies from 4 kW to 1.3 MW. It should be noted that the equipment working with wood, has a bulk combustor for most single fuel loading. In such devices, a high combustion intensity and substantially no incomplete combustion of the fuel mass.
In order to prevent the accumulation of small residual unburned fuel in the boiler structure has a reversing chamber at the outlet of the main combustion chamber.
On a note: Water units using wood as the main fuel is usually loaded manually. No less costly and heavy looks cleaning and cleaning of the equipment. Removal of the slag and ash components is performed manually.
In addition to separation techniques by heating fuels boilers must be separated by the method of circulation of the coolant. The most commonly used are the following:
- with natural circulation boilers;
- appliances with forced circulation;
- equipment, which uses the combined variant circulation;
- once-through boilers.
In the first case is the heating units, where the boiler water circulation is carried out by varying fluid density. In the second case we can speak about the circulation of the coolant caused by the operation of the electric pump. The combined aggregates used and the first and second embodiments, depending on the technological necessity. By the latter embodiment include heating devices, where the movement is carried out forced once-through of coolant in the downstream direction.
Water heaters having large capacity, equipped with fans, pumps air into the combustion chamber. Such models are usually equipped with exhaust fans, for a balanced draft and put in a separate room equipped with fire-fighting appliances.
conclusion
Boiler for solid fuels rather common phenomenon in our lives. Many small objects of city infrastructure, enterprises are heated using similar equipment. Economical fuel resources and high performance units contribute to the fact that this technique still continues to be in demand. Water apparatuses working in an organic or fossil fuels are not required to obtain the resolution setting.
The simplicity and clarity of the design of the unit, allows quick installation as soon as possible directly to the site to install the workpiece. During operation of the heating equipment of this type does not require special training and expertise. On most models, which are now in operation, set the minimum number of automation and other control devices. In addition to the common types of fuel, coal and wood, the furnace is anything that can burn well. Almost complete combustion of the fuel makes such aggregates environmentally-friendly industrial equipment.
