Rotary nozzle structure of medium-speed coal mill

Abstract

The invention relates to a rotary nozzle structure of a medium-speed coal mill. According to the rotary nozzle structure, a stationary seal ring is arranged on a coal mill inner cylinder wall; a nozzle is arranged on a coal mill grinding disc; an air passage is formed in the nozzle; a sealing structure is arranged on the outer side of the upper part of the nozzle; a vertical gap and a horizontal gap are simultaneously formed between the sealing structure and the nozzle; a pressing plate, round steel, an asbestos packing and a stationary seal ring sealing tooth are sequentially arranged on theside of the stationary seal ring from top to bottom; the lower part of the asbestos packing presses the stationary seal ring sealing tooth; the lower plane of the pressing plate and the upper plane ofthe stationary seal ring are arranged in a matched mode so as to ensure sealing between the stationary seal ring and the coal mill inner cylinder wall; a baffle ring is arranged on the stationary seal ring; and a high-temperature asbestos gasket is arranged between the stationary seal ring and the baffle ring so as to ensure the sealing effect. The rotary nozzle structure has the advantages thatthe sealing effect of a gap between a rotating seal ring and the stationary seal ring can be improved, electricity consumption and air consumption for the coal mill can be reduced, the wear resistanceand the reliability of the nozzle of the coal mill can be simultaneously improved, and the service life of the nozzle can be remarkably prolonged.

Description

technical field [0001] The invention relates to the mechanical field, in particular to a structure of a rotating nozzle for a medium-speed coal pulverizer used in a thermal power plant. technical background [0002] Coal mill is the main equipment of pulverizing system in coal-fired power station. The medium-speed vertical coal mill is generally used in China, which supplies pulverized coal fuel to boilers through grinding, drying, coarse and fine powder screening and transportation. The basic working process of this kind of coal mill is: drop the raw coal to be ground from the coal drop pipe in the center of the coal mill to the grinding disc, and the grinding disc rotates under the drive of the motor, and throws the raw coal to the grinding disc by means of centrifugal force. on the raceway; then, it is ground by grinding rollers. The grinding work is done by three grinding rollers, and the grinding rollers are spring-loaded or hydraulically loaded to provide grinding fo...

AI Technical Summary

Problems solved by technology

The main problems are: the nozzle 3' is very easy to wear and tear, which will lead to the inability to effectively organize the primary wind field, resulting in the increase of the ventilation resistance of the coal mill, the increase of the amount of pebble coal, the poor uniformity of the air powder, and the decline in the powder carrying capacity, which will lead to problems such as grinding Coal power consumption rises, output drops

[0009] During the operation of the medium-speed vertical coal mill, impurities such as pebbles and coal fall from the air passage 4' of the nozzle 3', and some impurities are stuck in the gap 6' between the nozzle 3' and the static ring 2'. The soot entrained in the primary wind will cause it to be scoured, and as the running time increases, it will lead to increased wear of the dynamic and static rings, greatly reducing the service life of the nozzle 3' of the medium-speed vertical coal-piercing machine

In addition, when the gap 6' between the nozzle 3' and the static ring 2' increases continuously, the ability of the medium-speed vertical coal mill nozzle 3' to organize the primary air is weakened, resulting in a significant reduction in the powder-carrying ability of the primary air, and the air-to-powder ratio Continuously increasing; at the same time, it affects the output of medium-speed vertical coal mills

After the air-to-powder ratio increases, the power consumption of the primary fan will increase; at the same time, it is not conducive to achieving low NO in the boiler X combustion

However, after the output of the coal mill is reduced, the power consumption rate of the factory will be increased, and the coal consumption of power supply will be increased.

[0010] At present, the nozzles of medium-speed coal mills are often produced by casting, and most of them are made of ordinary cast iron materials. In order to increase the life of the nozzles, the form is generally heavy and the quality is relatively large; the motor drives the coal mill to rotate together during operation, and the motor consumes a lot of energy.

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