The burners can be divided into three types according to different fuels: coal burners, oil burners and gas burners. Burners are also called burners, which can be divided into oil burners and gas burners according to the fuel; kiln burners and boiler burners according to the objects of use; industrial burners, civil burners and special burners according to the application fields. The oil burners are divided into light oil burners (such as diesel oil) and heavy oil burners (such as waste oil), and gas burners are divided into natural gas burners, liquefied gas burners, city gas burners, biogas burners, etc. The burner we usually refer to is the boiler burner.
Pulverized coal burner
It can be divided into swirl type and direct current type.
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Swirl pulverized coal burner: it is mainly composed of primary air cyclone, secondary air regulating baffle (swirl blade or volute) and primary and secondary air nozzles. It can be arranged on the front wall, two side walls or front and back walls of the combustion chamber. The air conveying pulverized coal is called primary air, which accounts for about 15-30% of the total air volume required for combustion. The pulverized coal air mixture is injected into the combustion chamber through the primary air nozzle of the burner. Another part of the air required for combustion is called secondary air. After the secondary air passes through the regulating baffle (swirl blade or volute) of the burner, it forms a rotating air flow, which combines with the primary air at the outlet of the burner to form a rotating jet. The negative pressure formed in the center of the jet draws the high temperature flue gas to the root of the flame. This part of high temperature flue gas is the main heat source of pulverized coal ignition. The diffuser cone at the outlet of primary air can increase the diffusion angle of primary air to enhance the entrainment of high temperature flue gas.
II.
Direct current pulverized coal burner: it is generally composed of several groups of primary and secondary air nozzles arranged along the height, which are arranged on each corner of the combustion chamber. The center line of the burner is tangent to an imaginary circle in the center of the combustion chamber, thus forming a horizontally rotating updraft in the combustion chamber. The primary and secondary air nozzles of each group of once through burners are distributed to meet the requirements of stable and complete combustion of different types of coal, and sometimes the generation of nitrogen oxides is also considered to be reduced.
Oil burner
The fuel oil burner mainly adopts atomization technology. The atomization principle of KMY bubble atomizer is: fuel oil and atomization medium (water steam or compressed air) generate a large number of oil in the bubble atomizer, and then spray out after the mixing chamber is fully mixed. Due to the high pressure difference, blasting atomization is realized. According to the laser detection in the Key Laboratory of aeroengine aerothermodynamics national defense science and technology, the average diameter of the atomized particles is SMD ≤ 23.76 μ m, which is not achieved by the general pneumatic atomization and mechanical atomization nozzles, and it is a new fuel atomization combustion technology.
In addition to the swirl type and direct current type similar to the pulverized coal burner, there is also a partial swirl type in the air conditioner of oil burner, that is, a flame stabilizer is arranged in the direct current type air conditioner to make a small amount of air (10-20%) flow through the flame stabilizer and generate rotary movement, and a central return area is formed at the outlet of the air conditioner to make the oil mist ignite stably and achieve low oxygen combustion.
Gas burner
There are mainly two kinds of natural gas burners and blast furnace gas burners. Large capacity natural gas burners mostly adopt multi gun air inlet advection type. The natural gas gun is placed in the air passage of the air conditioner. Because of the low calorific value of blast furnace gas and the difficulty of ignition, the blast furnace gas burner often burns in the hot channel and then sprays into the combustion chamber.
Biomass pellet fuel
In order to further study the combustion characteristics of biomass particle fuel and the fuel adaptability of automatic burner, based on pb-20 biomass particle burner, five kinds of particle fuel with ash content less than 25% (air dry basis) were selected in this paper. The effects of feed and air volume on combustion performance were studied respectively. The test results show that the granular fuel with ash content more than 20% is not suitable for this kind of biomass particle burners because of its insufficient combustion, unstable working conditions, low efficiency, large slagging and easy flameout; the recommended parameter for the granular fuel with ash content of 12.40% is feed quantity 4
Kg / h, fan speed 2600-2800 R / min, slag removal speed 3 R / min, 5 S / stop 35 s; the recommended control parameters for particulate fuel with ash content of 7.21% are feed volume 3-4 kg / h, fan speed 2600-2800
R / min, slag removal speed is 3 R / min, 5 S / stop for 60-55 s; for particulate fuel with ash value lower than 1%, feed rate is 3-4 kg / h, fan speed is 2600-2800
R / min, no slag cleaning is recommended. This study summarizes the fuel control parameters of biomass particle burners and provides data support for the popularization and application of the burners.
——Author：ebico