CN217550023U

CN217550023U - Primary air chamber flow equalizing device of medium speed coal mill

Info

Publication number: CN217550023U
Application number: CN202220925607.0U
Authority: CN
Inventors: 杨智远; 余冬; 王晓; 朱建巍
Original assignee: Beijing Lad Electric Technology Co ltd
Current assignee: Beijing Lad Electric Technology Co ltd
Priority date: 2022-04-21
Filing date: 2022-04-21
Publication date: 2022-10-11
Anticipated expiration: 2032-04-21

Abstract

The utility model relates to a plenum flow straightener for medium speed pulverizer of thermal power factory, it includes: the device comprises a nozzle, a guide plate, a base plate, a coal mill cylinder wall, a static ring and a grinding disc, wherein the guide plate is uniformly welded on the base plate at a certain angle and a certain distance; the backing plate is welded in the cylinder wall of the coal mill. The tangential angle of the guide plate and the cylinder wall of the coal mill is consistent with the inlet angle of the nozzle, and the angle is 30-45 degrees. The number of the guide plates is consistent with that of the nozzles of the coal mill, and the guide plates correspond to the nozzles of the coal mill one by one. The utility model discloses an install the meeting point that the guide plate can effectual change a wind additional at a plenum, make the wind flow field of low flow district tend to evenly, change the uneven current situation of rotating ring entry velocity of flow to a certain extent, make an amount of wind distribution more even, optimize a wind flow field, improved the ability of carrying the buggy to improve the powder process efficiency of powder process system, solved the problem of local wear in the coal pulverizer.

Description

Primary air chamber flow equalizing device of medium speed coal mill

Technical Field

The utility model relates to the field of machinary, especially indicate a flow straightener who is used for wind chamber of coal pulverizer of thermal power factory.

Technical Field

The medium-speed vertical coal mill is equipment commonly adopted by a domestic coal-fired power plant boiler pulverizing system, and mainly has the advantages that raw coal is ground into uniform coal powder by a grinding roller, primary air enters a primary air chamber of the coal mill through a primary air duct, an air-powder mixture ground into powder is conveyed upwards through a nozzle, and fine powder with qualified fineness is taken out of the coal mill from a separator by the primary air and is conveyed to a combustor for combustion; and the pulverized coal with unqualified fineness falls back to the grinding roller for secondary grinding.

When the traditional coal mill is designed and improved, the flow velocity of the nozzle of the coal mill is determined according to the average flow velocity of the air ring calculated according to the conditions such as the primary air flow of an inlet, the flow area of the nozzle and the like, and the characteristic of non-uniform distribution of primary air in an air chamber is not considered. However, it can be found from the analysis of the static pressure distribution of the primary plenum that there is a relatively large error in this distribution. The accuracy of the design can be ensured only by ensuring that the wind speed of the wind ring in the low-flow area is higher than the design requirement when the size of the nozzle is designed. However, the primary air is blown in from one side of the primary air chamber at the bottom of the coal mill, and the primary air chamber does not completely play a role in flow equalization and pressure equalization. The primary air enters the coal mill horizontally from one side of the coal mill through a primary air duct, is divided into two flows at the inlet of a primary air chamber to flow around a grinding disc, and after one circle of flow, the two flows meet at the opposite side of the inlet of the primary air chamber, and the speed of the meeting process is suddenly reduced, so that the static pressure is increased. The process of meeting causes the uneven distribution of the internal flow velocity and static pressure of the primary air chamber, thereby forming a vortex area to cause the uneven local air volume and air speed and the occurrence of a low-flow area. The coal pulverizer has the advantages that the coal powder carrying capacity is high in places with high static pressure, the scouring effect on internal parts and the barrel wall of the coal pulverizer is high after the coal pulverizer passes through the rotary nozzle, local abrasion is caused, the safe and economic operation of the coal pulverizer is seriously influenced, and the maintenance cost of the coal pulverizer in the later period is increased. Meanwhile, the primary air quantity is not uniformly distributed, so that the flow field of the primary air is disordered, the capability of conveying pulverized coal is reduced, and the pulverizing efficiency of a pulverizing system is reduced.

Disclosure of Invention

An object of the utility model is to overcome prior art not enough and provide a plenum flow straightener of medium speed pulverizer, it installs devices such as backing plate and guide plate additional in a plenum, makes a wind flow field tend to evenly, optimizes a wind flow field, improves the ability of carrying the buggy, improves the powder process efficiency of powder process system to solve the problem of local wear in the coal pulverizer.

The technical scheme of the utility model is that:

the primary air chamber structure of the coal mill is optimized by additionally arranging the base plate and the guide plate in the primary air chamber of the coal mill, the base plates and the guide plates with different sizes are arranged according to different coal mills, the angles of the guide plates and the nozzles are consistent, and the guide plates and the nozzles are in one-to-one correspondence, so that the flow area of the primary air chamber is uniform. And determining the quantity, the distance, the specification and the like of the additionally arranged guide plates and determining the optimal design of the guide plate arrangement through field measurement and analysis calculation.

The flow equalizing device for the primary air chamber of the coal mill comprises a base plate arranged on the inner cylinder wall of the primary air chamber, guide plates welded on the base plate and the primary air chamber uniformly distributed in the area below a nozzle at a certain angle and a certain interval, so that the nozzles and the guide plates are consistent in quantity and are in one-to-one correspondence in position.

The tangent angle of the guide plate and the cylinder wall is consistent with the angle of the nozzle inlet, and the inclination angle is about 30-45 degrees, so that the static pressure and the speed distribution on the opposite side of the primary air inlet are more uniform by the guide plate within the angle range.

The length of the guide plate is about 600-700 mm, the guide plate is ensured to extend to the inner side of the lower edge of the nozzle, turbulence and backflow are reduced by the guide plate within the length range, and the guide effect of the guide plate is enhanced; the width of the base plate is designed by measuring the distance between the nozzle and the slag discharge scraper, and the width of the guide plate refers to the width of the base plate, so that the guide plate can be extended as far as possible and uniformly arranged, and the operation of the components such as the pebble coal scraper and the like is not influenced.

The base plate is made of alloy steel with good flexibility, and the thickness of the base plate is about 5mm, so that the base plate can be tightly attached to the cylinder wall and can be firmly welded with the guide plate; the guide plate adopts wear-resisting alloy steel, guide plate thickness is about 10mm, guarantees its life-span, can guarantee the water conservancy diversion effect for a long time to guarantee the efficiency of a wind the highest.

The base plate and the guide plate are integrally installed, the guide plate is planned to be in a position on the base plate in advance through calculation and is welded on the base plate, and therefore construction is convenient, and gaps are uniform; and then the backing plate with the guide plate is welded on the cylinder wall of the coal mill, so that the construction workload in the coal mill is reduced, the inspection and the trimming are convenient, the welding quality is improved, the service life is prolonged, and the installation is convenient and quick.

The guide plates are consistent with nozzles of the coal mill in number and are in one-to-one correspondence, the arrangement mode does not hinder the discharge of pebble coal in the primary air chamber, and the smooth passing of primary air of the nozzles is not hindered.

The utility model has the advantages that: through installing devices such as guide plate additional in primary plenum, the meeting point of wind can effectual change, makes the primary air flow field in low flow district tend to evenly, changes the uneven current situation of nozzle entry velocity of flow to a certain extent, makes primary air distribution more even, optimizes the primary air flow field, improves the ability of carrying the buggy to improve the powder process efficiency of powder process system. On the other hand, the uneven main reason that leads to the inside uneven wearing and tearing of coal pulverizer is led to the primary air chamber unilateral entry, and the additional installation guide plate also can play the effect of improving wearing and tearing.

In addition, backing plate and guide plate are integrative installation, can reduce at the inside construction work load of coal pulverizer, and the inspection and the repairment of being convenient for improve welding quality, increase of service life, simple to operate is swift.

Drawings

FIG. 1 is a sectional view of the internal mechanism of the primary air chamber of a medium-speed vertical coal mill.

FIG. 2 is a side view of the internal mechanism of the primary air chamber of the medium speed vertical coal mill.

Fig. 3 is a top view of the internal structure of the primary air chamber of the medium-speed vertical coal mill.

The reference numbers in the figures illustrate:

1. a nozzle; 2. a baffle; 3. a base plate; 4. a coal mill cylinder wall; 5. a stationary ring;

6. a grinding disc; 7. the primary air duct inlet.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and examples.

As shown in the figure, the utility model discloses plenum flow straightener once of medium speed pulverizer, it includes: the device comprises a nozzle 1, a guide plate 2, a base plate 3, a coal mill cylinder wall 4, a static ring 5, a grinding disc 6 and a primary air duct inlet 7. Wherein, the guide plates 2 are uniformly welded on the backing plate 3 at a certain angle and a certain distance; the backing plate 3 is welded inside the coal mill cylinder wall 4.

The tangential angle of the guide plate 2 and the coal mill cylinder wall 4 is consistent with the inlet angle of the nozzle 1 and is between 30 and 45 degrees. The guide plate 2 in the angle range enables the static pressure and the speed distribution on the opposite side of the primary air inlet to be more uniform.

The number of the guide plates 2 is consistent with that of the nozzles 1 of the coal mill, and the guide plates correspond to the installation positions one by one.

The length of the guide plate 2 is about 600-700 mm. This length ensures that it extends to the inside of the lower edge of the nozzle.

The width of the guide plate 2 can be determined according to the primary air chamber scraper. The principle is that the normal rotation of a primary air chamber scraper is not hindered, and the pebble coal can be discharged normally; secondly, the inlet profile of the nozzle 1 is not hindered, and the smooth passing of primary air of the nozzle 1 is not influenced. The guide plate 2 is made of high-wear-resistance alloy steel, the thickness of the guide plate is 10-30mm, the service life of the guide plate is guaranteed, and the guide effect can be guaranteed for a long time.

The backing plate 3 is made of alloy steel with good flexibility, and the thickness of the backing plate is 3-15mm, so that the backing plate can be tightly attached to the cylinder wall and can be firmly welded with the guide plate.

The base plate 3 and the guide plate 2 are integrally installed. The guide plate 2 can be welded on the backing plate 3 in advance; and then the backing plate 3 welded with the guide plate 2 is integrally welded inside the cylinder wall 4 of the coal mill.

When primary air enters a primary air chamber of the coal mill through a primary air channel inlet 7, the primary air entering the nozzle 1 tends to be uniform under the action of the guide plate 2, and meanwhile, the primary air upwards reaches a grinding area of a grinding disc 6 of the coal mill through an air channel of the nozzle 1, blows pulverized coal ground into powder upwards and conveys the pulverized coal to an outlet of the coal mill until the pulverized coal reaches a boiler for combustion.

Claims

1. A primary air chamber flow equalizing device of a medium speed coal mill comprises: nozzle, guide plate, backing plate, coal pulverizer section of thick bamboo wall, quiet ring, mill and primary air duct entry, its characterized in that: the guide plates are uniformly welded on the backing plate at a certain angle and a certain distance; the backing plate is welded in the cylinder wall of the coal mill.

2. The primary air chamber flow equalizing device of the medium speed coal mill of claim 1, wherein: the tangential angle of the guide plate and the cylinder wall of the coal mill is consistent with the inlet angle of the nozzle, and the angle is 30-45 degrees.

3. The primary air chamber flow equalizing device of the medium speed coal mill of claim 1, wherein: the number of the guide plates is consistent with that of the nozzles of the coal mill, and the positions of the guide plates correspond to those of the nozzles of the coal mill one by one.

4. The primary air chamber flow equalizing device of the medium speed coal mill of claim 1, wherein: the length of the guide plate is 600-700 mm; this length extends to the inside of the lower edge of the nozzle.

5. The primary air chamber flow equalizing device of the medium speed coal mill of claim 1, wherein: the width of the guide plate can be determined according to the primary air chamber scraper plate so as to ensure that the pebble coal can be normally discharged; the smooth passing of the primary air of the nozzle is not influenced.

6. The primary air chamber flow equalizing device of the medium speed coal mill of claim 1, wherein: the guide plate is made of high-wear-resistance alloy steel, and the thickness of the guide plate is 10-30mm.

7. The primary air chamber flow equalizing device of the medium speed coal mill of claim 1, wherein: the backing plate is made of alloy steel with good flexibility, and the thickness of the backing plate is 3-15mm.

8. The primary air chamber flow equalizing device of the medium speed coal mill of claim 1, wherein: the guide plate is welded on the backing plate to form a whole; and then the whole body is welded in the cylinder wall of the coal mill.

9. The primary air chamber flow equalizing device of the medium speed coal mill of claim 1, wherein: it includes: when primary air enters a primary air chamber of the coal mill through a primary air duct inlet, the primary air entering the nozzle tends to be uniform under the action of the guide plate, and meanwhile, the primary air upwards reaches a grinding area of a grinding disc of the coal mill through an air passage of the nozzle, blows pulverized coal which is ground into powder upwards and conveys the pulverized coal to an outlet of the coal mill until the pulverized coal reaches a boiler for combustion.