Five factors affecting the burning of chain furnace
2018-04-02 15:35:07 Category：Industry information Visits
【Introduction】Most of you may know a lot about wall hanging stove, but if someone talks about chain furnace, you may be confused. Chain grate stoker is a kind of Stoker furnace with high mechanization degree. It is widely used in industrial boiler.
Most of you may know a lot about wall hanging stove, but if someone talks about chain furnace, you may be confused. Chain grate stoker is a kind of Stoker furnace with high mechanization degree. It is widely used in industrial boiler. It is mainly through the reducer to drive the chain grate to turn the coal from the front, to the tail of the boiler, to improve the combustion efficiency. When the chain is transferred to the bottom, the air cooling will cool down and the grate piece will not be burned. Then this article will analyze the factors that affect the burning of the chain furnace from five aspects, and provide some reference for the safety, stability and economic operation of the user in the use of chain furnace.
1, the adjustment of the thickness of coal seam and the speed of the grate
Under the condition of certain load of boiler, the thicker the coal seam is, the slower the speed of the grate will be, and the longer the coal will stay in the furnace, which is not necessarily beneficial for combustion. Especially when burning mixed coal and coal end, the thicker the coal seam is, the lower the heat absorption and ignition delay, and because of the large resistance of the coal seam ventilation, the wind pressure under the grate is increased, and the coal seams can be blown up and the fire bed is destroyed. It is easy to press fire where the resistance of coal seam is relatively large, which makes the mechanical incomplete combustion heat loss increase, and the wind leakage is easy to be perforated in a relatively small area, and the excess coefficient of air in the furnace is increased. Coal with small particle size is difficult to ventilate, and thin coal seam reduces ventilation resistance, which is good for ventilation. Therefore, generally speaking, the operation of chain grate stoves should be operated by thin coal seam and low wind pressure.
The thickness of coal seam and the speed of grate are related to the nature of the coal and the load of the boiler. Under normal operating conditions, most of coal should not exceed 75~180. It generally uses thin coal seam to burn fast speed, and the thickness of coal seam can be 90~120. When bituminous coal or Inferior Bituminous coal and anthracite are burned, the thickness of coal seam can be used to 100~130. Slow burning of thick coal seam is used in burning anthracite coal, and thickness of coal seam is suggested big. In 130 mm; coal when humidity is big, should adopt the slow combustion of thick coal seam. At the same time, the size of coal should also be adjusted properly. For example, the thickness of coal seam should be between 75~100 when coal and general granularity is used. When the grain size is less than 50, the thickness of coal seam can be 150~200. When the grain size is large, the thick coal seam should be used to keep the uniform fire bed. In addition, the thick coal should be thickened, and the thickness of the grate surface should be thicker. Coal seam, if the front arch temperature is too low, and if there is difficulty in igniting, the coal seam should also be properly thickened.
Generally speaking, a chain grate burning little volatile coal is not easy to catch fire, so the speed of grate should be slowed down so as to keep the coal bed on fire. If the speed of the grate is too fast, it is easy to break off the fire. When burning the coal with large volatile matter, the slow speed of the grate will cause the ignition point to be too close, so that the coal gate can be burned. Therefore, the speed of the grate should be faster.
The size of the blast pressure and the thickness of the coal seam is directly related to the thickness of the coal seam. The coal seam thickness is big, the wind pressure is also big, otherwise the wind is not permeable, the burning effect is poor; the coal seam thickness is small, the wind pressure is also small, otherwise it is easy to blow away the fine coal, cause the fire mouth, the fire part air is too much, the burning is strong, and the other parts are not enough air, the fire is not good, the whole fire bed combustion is uneven, machinery is not completely burning heat. Loss and exhaust heat loss increase, resulting in reduction of boiler thermal efficiency.
Based on the above analysis, coal seam thickness, grate speed and wind pressure can be divided into three following three ways under the condition of fixed load.
(1) thick coal seam, high wind pressure, slow speed;
(2) thin coal layer, low wind pressure, fast speed;
(3) middle coal seam, medium wind pressure, medium velocity.
Which kind of cooperation method is adopted in operation depends mainly on the size of coal and coal. For example, burning anthracite, inferior bituminous coal or large lump coal can adopt the first coordination method. Burning bituminous coal or coal can be used in second ways.
Of course, the three coordination methods are relative to a certain load, but not fixed. For example, when the load is high, the coal seam should be thicker and the wind pressure should be higher. The speed of the grate should be faster, and vice versa. With different coal types, the values of coal seam, air pressure and grate speed adopted by the above methods are different, so they should be allocated according to specific circumstances.
Under normal circumstances, the thickness of coal seam does not always change with the increase or decrease of load. Regular change will affect the stability of fire bed combustion. It is recommended to use the same coal seam thickness in the 50 ~ 100% rated load range. When load changes little, combustion adjustment mainly changes the speed and air volume of grate. When the load is increased, the air volume should be increased first, then the wind is added, then the grate speed is increased. When the load is reduced, the air volume should be reduced, the wind is reduced first, then the wind is reduced, and then the grate speed is reduced.
The coal seam thickness should be adjusted when the load changes or coal types change. For each furnace, in a certain load range, it should be used in a thick coal seam. The operators should find out the rules and scientific fireplaces through the experience accumulated in practice.
2, adjustment of subsection air supply
The opening of the segmented valve under the chain grate or the pressure of the subsection wind chamber is usually determined by the concrete structure of the coal, grate and furnace arch, and it is related to the operating conditions of the air pressure and the combustion state of the fire bed. In order to ensure the reasonable operation of the burning process of the chain furnace, the air distribution mode is generally small in the front and back of the grate, but the middle is gradually increasing. The front of the grate is mainly using a small amount of air supply and radiation heat in the furnace.
Title：Five factors affecting the burning of chain furnace URL：http://www.boroachina.com/en/news/847.html