08
2023
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08
Reasons for blockage of coal drop pipe in raw coal bunker
the impact of raw coal composition:
Coal contains a certain amount of clay, carbonate, pyrite and other minerals, they constitute the ash of coal. The clay can absorb water and disperse into colloidal particles, which is pasty and has cohesiveness. Therefore, the content and performance of clay minerals have a great influence on the caking of coal, and when the content is too high, it often leads to caking and blocking of raw coal. The smaller the average particle size of the coal, the more fine powder, the larger the specific surface area, the higher the surface free enthalpy, the larger the force between the particles, the stronger the internal force, the macroscopic performance of the coal is strong, such as coal slime.
Structure type of coal drop pipe section of raw coal bunker:
The common structural types of coal drop pipe section are rectangular cross-section pipe and circular cross-section pipe. The raw coal near the four corners of the wall of the rectangular section coal drop pipe is easily bonded to the four corners for a long time due to "double-sided friction" and extrusion. In the case of the same half-top angle, it is easier to accumulate coal than the circular section coal drop pipe. Especially when the water content of coal particles is large, the content of slime is high, and the agglomeration is very strong, the flow of coal in the drop pipe is more difficult, and the probability of arch blockage increases. Structurally, the probability of blockage of the circular cross-section coal chute is relatively small.
the impact of coal pipe material:
Commonly used are ordinary carbon steel and stainless steel. Made of ordinary carbon steel, the inner wall of the pipeline is easy to rust and the surface is rough, causing pulverized coal to collect on its surface, especially when the water content of coal is 8% ~ 12%, it is easier to bond on the pipe wall, resulting in blockage of the coal drop pipe due to increased coal resistance. Stainless steel plate itself has low hardness and poor wear resistance, but its coefficient of friction with materials is 30% lower than that of ordinary steel, and its sliding property is good, so its resistance to coal flow is small, which is beneficial to the flow of raw coal.
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