Adjustable coal dust distributor

Abstract

The invention provides an adjustable coal dust distributor which comprises a thick phase inner pipe coaxially arranged in a coal dust cylinder at an outlet of a coal mill. A thin phase outer ring is formed between the thick phase inner pipe and the wall of the coal dust cylinder at the outlet of the coal mill. The section of the thick phase inner pipe and the section of the thin phase outer ring are coaxial and are equally divided into parts, wherein the number of the parts is the same with that of primary air pipes; and each equally-divided section part is connected with one primary air pipe, and thick phase adjusting valves and thin phase adjusting valves are arranged on the equally-divided section parts respectively. A reducing pipe is arranged at the front end of the coal dust cylinder at the outlet of the coal mill, and a shutter ring is arranged at the front end of the reducing pipe. Coal dust at the outlet of the coal mill is condensed through the shutter ring, under the inertia effect, thick and thin separation with the thick part inside and the thin part outside is conducted, thick coal dust is condensed at the center, thin coal dust is distributed on the periphery, a thick phase and a thin phase are equally divided, all the corresponding parts of thick and thin coal dust enter the primary air pipes and are evenly distributed; and the adjusting valves are arranged for all the parts of the thick phase and the thin phase, and adjustment is convenient.

Description

technical field [0001] The invention relates to a pulverized coal distributor in a thermal power plant, in particular to a pulverized coal distributor capable of evenly distributing the air volume and the amount of pulverized coal to each primary air duct of the same coal mill. Background technique [0002] The pulverized coal distributor is generally used on the main pulverized coal pipeline at the outlet of the coal mill. Through the distribution of the pulverized coal distributor, it can achieve the purpose of evenly distributing the air volume and the amount of pulverized coal for each primary air duct of the same coal mill. [0003] Whether the pulverized coal distribution of each primary air duct at the outlet of the coal mill is evenly distributed has a great influence on the combustion of the boiler. When the coal distribution is uneven, the actual amount of pulverized coal entering each burner varies greatly, and the air-powder ratio is prone to mismatch, resulting ...

AI Technical Summary

Problems solved by technology

[0005] Due to the deviation of the amount of pulverized coal, it will lead to a large deviation of the local heat load of the boiler, which will cause the heat deviation of the outlet of the boiler furnace

[0006] (2) Local overheating and high temperature corrosion

[0007] Due to the deviation of the amount of pulverized coal, it will lead to the imbalance of air-coal ratio in some areas, and the area with large amount of coal will easily lead to overheating of local water-cooled wall pipes due to high heat load

In addition, the area with high powder content is likely to cause insufficient oxygen, and the reducing atmosphere is severe, which will cause high temperature corrosion for a long time

[0008] (3) Insufficient combustion

[0009] Due to the deviation of the amount of pulverized coal, it will cause local wind and powder mismatch: the area with a large amount of powder may not necessarily have a large air volume, which will cause local hypoxia and greatly restrict the burnout of pulverized coal.

[0010] (4) Fluctuation of steam temperature and pressure with variable load

[0011] Due to the deviation of the amount of pulverized coal, the air powder will be mixed unevenly, which will easily cause the local ignition time in the furnace to vary, and the combustion structure will deteriorate, which will cause fluctuations in steam temperature, steam pressure and furnace negative pressure.

[0012] As mentioned above, the pulverized coal distributor has a great influence on the combustion of the boiler, but at present, many power plants do not install the pulverized coal distributor, because the pulverized coal distributor currently on the market is a grid type or a line ,like figure 1 As shown, the primary air ducts at the outlet of the pulverized coal distributor are arranged from left to right, and the pulverized coal concentration at the outlet of the pulverizer is due to the relationship between the airflow rotation and local resistance in the pulverizer, and the pulverized coal concentration at the left and right sides usually appears. In the case of large deviation, that is, the concentration of pulverized coal on the left (right) side is several times that of the pulverized coal on the right (left) side. It is difficult to achieve the balance of powder volume and wind speed in each primary air duct through adjustment

In summary, because the design of the traditional pulverized coal distributor does not take into account the large deviation of the pulverized coal concentration on the left and right sides, the traditional pulverized coal distributor has poor adjustability in actual use

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