Adjustable nozzle structure of medium-speed coal mill

Abstract

The invention relates to an adjustable nozzle structure of a medium-speed coal mill. The adjustable nozzle structure comprises a rotary nozzle, an upper sealing structure and an adjustable device, wherein the adjustable device is located between the rotary nozzle and the upper sealing structure; the adjustable device is located above an outlet of the rotary nozzle; the upper sealing structure is fixedly connected with a barrel wall; a mechanical transmission part for controlling the adjustable device is arranged outside the barrel wall; and the mechanical transmission part is provided with a crank connecting rod structure and can be used for pushing the adjustable device to retract frontward and backward. By adopting the mechanical transmission part, a flow area of the outlet of the rotary nozzle is controlled in real time and an air speed of the outlet is changed. The rotary nozzle can rotate integrally and has no dynamic and static friction. The adjustable nozzle structure is simple in structure, convenient to mount and convenient to overhaul. The adjustable nozzle structure of the medium-speed coal mill is applicable to changes of fired coal quality, equipment and operating conditions; the capability of screening impurities of raw coal by the nozzle can be improved; and the output of the coal mill is guaranteed and the energy consumption of the coal mill is reduced.

Description

technical field [0001] The invention relates to the mechanical field, in particular to an adjustable nozzle structure of a medium-speed coal pulverizer in a thermal power plant. Background technique [0002] At present, the rotating nozzle ring used in the medium-speed coal pulverizer of the thermal power plant is mainly composed of a moving ring and a static ring. Among them, the moving ring is connected with the grinding disc, and rotates with the grinding disc during operation; the static ring is connected with the barrel wall of the coal mill. A certain gap is set between the moving ring and the static ring. [0003] The main problems that exist are: [0004] The flow area of ​​the coal mill nozzle cannot adapt to the change of the type of coal being pulverized. For example, when the coal pulverized by the coal mill is a high-moisture coal, in order to ensure the drying output, it is necessary to increase the flow area of ​​the hot primary air and reduce the ventilati...

AI Technical Summary

Problems solved by technology

At present, thermal power plants can only control the amount of pebble coal by adjusting the primary air volume

In addition, when the coal quality changes, the nozzle has no ability to screen coal and impurities (stones, pyrite, etc.) due to the non-adjustable wind speed

For power plants that burn low-quality coal with a lot of impurities, the impurities cannot be discharged in time, and they are repeatedly ground in the coal mill, resulting in serious wear of the coal mill and increased power consumption

[0006] In addition, with the increase of running time, the wear of the coal mill motor ring and static ring increases, the ability of the coal mill nozzle to organize the primary air is weakened, the ability of the primary air to carry the powder is greatly reduced, and the amount of pebble coal is significantly increased, which affects the coal mill. Contribute

In addition, the wear of the grinding rollers makes the raw coal not fully ground and is discharged into the stone coal box

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