CN217503635U - Bottom air supporting system of opposed combustion boiler and opposed combustion boiler - Google Patents

Abstract

The utility model discloses a bottom air supporting system of a hedging combustion boiler and the hedging combustion boiler, wherein the bottom air supporting system comprises a plurality of bottom air nozzles, a plurality of bottom air connecting pipes and a bottom air main pipe; the plurality of bottom air nozzles are communicated with the plurality of bottom air connecting pipes in a one-to-one correspondence manner; the plurality of bottom air connecting pipes are communicated with the bottom air main pipe; the bottom air supporting nozzle is positioned between a lower layer cyclone burner and a cold ash hopper of the opposed firing boiler; the free end of the bottom supporting air nozzle extends into the interior of the opposed firing boiler. The system supports the segregated coal dust particles or unburned coal dust airflow by means of the high-speed jet flow of the bottom supporting air, and prevents the coal dust particles or the unburned coal dust airflow from falling into the area of the cold dust hopper to cause high-temperature corrosion or slagging of the water-cooled wall of the cold dust hopper.

Description

Bottom air supporting system of opposed firing boiler and opposed firing boiler

Technical Field

The utility model belongs to coal fired power plant boiler field relates to an offset combustion boiler holds in palm end wind system and an offset combustion boiler.

Background

The opposite-impact combustion of front and back walls is a main combustion mode of coal-fired power station boiler, and is characterized by that several layers of cyclone burners are symmetrically arranged on the front wall and back wall of the boiler, and the high-temp. smoke gas can be sucked by means of self-reflux of burners so as to implement ignition and combustion of pulverized coal.

The high-temperature corrosion of the opposed firing boiler usually occurs in the middle area of the water-cooled walls of the two side walls, the elevation is between the middle-layer pulverized coal burner and the lower-layer over-fired air burner, and the problem of high-temperature corrosion is rarely found in the area of the cold ash bucket. However, in recent years, the problem of high-temperature corrosion of the water-cooled wall is also found in the elevation region from the cold ash bucket of some boilers to the lower pulverized coal burner, for example, the water-cooled wall in the upper and lower regions of the corner of the cold ash bucket leaks in the operation of a 1000MW opposed firing boiler, the leakage is caused by the reduction of the wall thickness of the tube wall due to the high-temperature corrosion of the water-cooled wall in the cold ash bucket region, and the main reasons for the high-temperature corrosion of the cold ash bucket region are that the air speed of the nozzle of the lowermost burner of the opposed firing boiler is low and the pulverized coal particles are coarse.

Most of opposite-burning boiler bottom coal powder burner is plasma burner, because the plasma burner needs to arrange plasma generator and other devices, so compare with ordinary coal powder burner, plasma burner nozzle area is great. Under the same air quantity, the air speed of a nozzle of the plasma burner is lower than that of the pulverized coal burner, pulverized coal particles fall to a cold ash bucket area at the bottom of a hearth for combustion after pulverized coal airflow flows through the plasma burner after incomplete combustion, and oxygen in the cold ash bucket area is consumed, so that the reducing atmosphere of the cold ash bucket area is enhanced, and conditions are created for high-temperature corrosion; in addition, unburned coal powder directly falls to deslagging equipment, causes the slag combustible content to be higher, reduces boiler operation economic nature.

Each coal mill of the opposed firing boiler corresponds to a layer of combustor, when in operation, the lower-layer coal mill is firstly put into operation, the corresponding lower-layer combustor is put into operation, and with the increase of load, the middle-layer or upper-layer coal mill is put into operation, and the corresponding middle-layer or upper-layer pulverized coal combustor is put into operation; and when the load is reduced, the upper coal mill is preferentially stopped, and the corresponding upper pulverized coal burner is stopped. Because the steady burning layer of the boiler is the lower burner, the operation time of the lower coal mill and the lower burner is longest, the grinding roller and the lining plate of the lower coal mill are worn most seriously, so that pulverized coal ground by the lower coal mill is coarse, and when pulverized coal airflow enters a hearth through the lower burner to burn, pulverized coal particles easily fall into a cold ash bucket area due to coarse pulverized coal particles, so that the problem of high-temperature corrosion of a water-cooled wall of the cold ash bucket area is caused, and the content of slag combustible substances is high.

SUMMERY OF THE UTILITY MODEL

To the problem that exists among the prior art, the utility model provides a hedging combustion boiler holds in palm end wind system and hedging combustion boiler to effectively solved the regional high temperature corrosion of hedging combustion boiler cold ash bucket, slagging scorification problem, reduced boiler slag combustible content, promote boiler thermal efficiency.

The utility model discloses a realize through following technical scheme:

a bottom air supporting system of an opposed firing boiler comprises a plurality of bottom air nozzles, a plurality of bottom air connecting pipes and a bottom air main pipe;

the bottom air nozzles and the bottom air connecting pipes are communicated one by one;

the bottom air supporting connecting pipes are communicated with the bottom air supporting main pipe;

the bottom air supporting nozzle is positioned between a lower layer cyclone burner and a cold ash hopper of the opposed firing boiler;

and the free end of the bottom supporting air nozzle extends into the opposed combustion boiler.

Preferably, the free end of the bottom supporting air main pipe is communicated with the hot primary air main pipe or the combustor air box.

Preferably, the number of the bottom supporting air nozzles is consistent with that of the lower-layer cyclone burners of the opposed combustion boiler, and the bottom supporting air nozzles are positioned right below the lower-layer cyclone burners of the opposed combustion boiler.

Preferably, an electric regulating valve is arranged on the bottom supporting air connecting pipe.

Preferably, an electric stop valve is arranged on the bottom supporting air connecting pipe.

Preferably, the bottom supporting wind connecting pipe is provided with a non-metal expansion joint.

Preferably, the vertical distance between the bottom supporting air nozzle and the lower layer cyclone burner of the opposed firing boiler is 2.5-4 m.

Preferably, the cross-sectional area of the bottom supporting air nozzle is the same as that of a pulverized coal nozzle of a lower-layer cyclone burner of the opposed firing boiler.

Preferably, the bottom supporting air nozzle is made of stainless steel.

An opposed firing boiler comprises the bottom supporting air system.

Compared with the prior art, the utility model discloses following profitable technological effect has:

a bottom air supporting system of an opposed firing boiler is characterized in that a bottom air supporting nozzle is arranged between a lower-layer cyclone burner of the opposed firing boiler and a hearth ash cooling bucket, a bottom air supporting connecting pipe and a bottom air supporting main pipe are arranged and communicated with the bottom air supporting nozzle, the free end of the bottom air supporting nozzle extends into the interior of the opposed firing boiler, incoming air in the bottom air supporting main pipe enters each bottom air supporting nozzle through the bottom air supporting connecting pipe, and the incoming air enters a hearth through the high-speed jet of the bottom air supporting nozzle. The system supports the segregated coal dust particles or unburned coal dust airflow by means of the high-speed jet flow of the bottom supporting air, and prevents the coal dust particles or the unburned coal dust airflow from falling into the area of the cold dust hopper to cause high-temperature corrosion or slagging of the water-cooled wall of the cold dust hopper. The bottom air provides oxygen required by combustion and burnout for the separated coal dust particles, promotes the burnout of the coal dust, reduces the content of slag combustible, and improves the thermal efficiency of the boiler.

Furthermore, the free end of the bottom supporting air main pipe is communicated with the hot primary air main pipe or the combustor air box, the hot primary air main pipe or the combustor air box can be selected according to the severity of corrosion and slag bonding of the cold ash bucket, if the corrosion and slag bonding of the cold ash bucket are serious, the hot primary air main pipe with high air pressure is suitable for the air source of the bottom supporting air main pipe; if not serious, the air source of the bottom supporting air main pipe can use a combustor air box with lower air pressure, so that the use flexibility of the device is improved.

Furthermore, the quantity of the bottom supporting air nozzles is consistent with that of the lower-layer cyclone burners of the opposed firing boiler, and the bottom supporting air nozzles are positioned right below the lower-layer cyclone burners of the opposed firing boiler, so that the upward supporting force of the bottom supporting air on separated falling pulverized coal particles and pulverized coal airflow which is not completely burned out is effectively improved, and the problem of high-temperature corrosion of the water-cooled wall in the cold ash bucket area is effectively prevented.

Furthermore, the arrangement of the electric regulating valve and the electric stop valve can regulate the air quantity and the air speed entering the bottom supporting air nozzle according to the slagging and high-temperature corrosion conditions of different positions of the cold ash bucket, so that the use flexibility of the device is improved.

Furthermore, the arrangement of the nonmetal expansion joint effectively relieves the radial expansion and the axial expansion of the bottom supporting wind connecting pipe in the using process, and the running safety of equipment is ensured on the basis of controlling the cost of the equipment.

Furthermore, the vertical distance between the bottom air supporting nozzle and the lower-layer cyclone burner of the opposed firing boiler is 2.5-4 m, the vertical distance is close to that between the lower-layer cyclone burner and the middle-layer cyclone burner, the normal firing and the combustion of the lower-layer cyclone burner cannot be influenced by the bottom air supporting arrangement, and the oxygen amount required in the initial firing stage of the coal powder of the lower-layer cyclone burner cannot be increased due to the bottom air supporting arrangement, so that the low-nitrogen combustion effect of the lower-layer cyclone burner is influenced.

Furthermore, the cross-sectional area of the bottom supporting air nozzle is the same as that of the pulverized coal nozzle of the lower-layer cyclone burner of the opposed firing boiler, so that the segregated pulverized coal particles can be effectively supported.

Furthermore, the bottom supporting air nozzle is made of high-temperature-resistant stainless steel, so that the service life of the device is prolonged.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural view of a bottom air supporting system of an opposed combustion boiler of the present invention;

fig. 2 is a schematic view of a structure of a bottom air supporting system of the opposed combustion boiler arranged on the opposed combustion boiler according to the present invention;

fig. 3 is a schematic top view of a bottom air supporting system of an opposed combustion boiler according to the present invention;

FIG. 4 is a schematic view of a lower layer cyclone burner in the prior art.

Wherein: 1. the device comprises a front wall, a rear wall, a lower layer cyclone burner, a bottom supporting air nozzle, a cold ash hopper upper folding point, a bottom supporting air main pipe, a bottom supporting air connecting pipe, a motor-driven adjusting valve, a motor-driven stop valve, a nonmetal expansion joint, a pulverized coal nozzle, a coal powder nozzle, an inner secondary air nozzle, an outer secondary air nozzle, a rear wall, a lower layer cyclone burner, a rear wall, a bottom supporting air nozzle, a cold ash hopper upper folding point, a bottom supporting air main pipe, a bottom supporting air connecting pipe, a coal powder nozzle, a coal powder adjusting valve, a motor-driven stop valve, a nonmetal expansion joint, a pulverized coal nozzle, a coal powder nozzle, an inner secondary air nozzle, a coal powder adjusting valve, an inner secondary air nozzle, an outer secondary air nozzle, a rear wall, a lower layer cyclone burner, a cold ash hopper, a lower layer, a cold ash hopper, a rear wall.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that, if the terms "upper", "lower", "horizontal", "inner", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship that the product of the present invention is usually placed when in use, the description is only for convenience of description and simplification, but the indication or suggestion that the device or element to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be interpreted as limiting the present invention. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

Furthermore, the term "horizontal", if present, does not mean that the component is required to be absolutely horizontal, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the embodiments of the present invention, it should be further noted that unless explicitly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

The present invention will be described in further detail with reference to the accompanying drawings:

as shown in fig. 1, a bottom air supporting system of an opposed firing boiler comprises a plurality of bottom air nozzles 4, a plurality of bottom air connecting pipes 8, a bottom air main pipe 7, an electric regulating valve 9, an electric stop valve 10 and a nonmetal expansion joint 11, wherein the plurality of bottom air nozzles 4 and the plurality of bottom air connecting pipes 8 are correspondingly communicated one by one, and the plurality of bottom air connecting pipes 8 are communicated with the bottom air main pipe 7; and the electric regulating valve 9, the electric stop valve 10 and the non-metal expansion joint 11 are arranged on the bottom supporting air connecting pipe 8. The arrangement of the electric regulating valve 9 and the electric stop valve 10 can regulate the air volume and the air speed entering the bottom supporting air nozzle according to the slagging and high-temperature corrosion conditions of different positions of the cold ash bucket, if the high-temperature corrosion and the slagging of the water-cooled wall at a certain position of the cold ash bucket are serious, the electric regulating valve of the bottom supporting air nozzle corresponding to the bottom supporting air connecting pipe above the position can be increased, and the air volume and the air speed of the bottom supporting air nozzle are improved. The arrangement of the nonmetal expansion joint 11 effectively relieves the radial expansion and the axial expansion of the bottom supporting wind connecting pipe in the using process, and ensures the safety of the operation of equipment. The free end of the bottom supporting air main pipe 7 is communicated with the hot primary air main pipe or the combustor air box, so that the hot primary air main pipe or the combustor air box can be selected according to the severity of corrosion and slag bonding of the cold ash bucket, if the corrosion and slag bonding of the cold ash bucket are severe, the pressure of hot primary air in the boiler hot primary air main pipe is 7kPa-10kPa, and the hot primary air main pipe with higher air pressure is used as the air source of the bottom supporting air main pipe; if the secondary air pressure in the air box of the burner is not serious, the secondary air pressure in the air box of the burner is 0.2kPa-0.6kPa, the air source of the bottom supporting air main pipe can use the air box of the burner with lower air pressure, and the use flexibility of the device is improved. The cross section of the bottom air nozzle 4 is circular, and the cross section area of the bottom air nozzle 4 is the same as that of the pulverized coal nozzle 12 of the lower-layer cyclone burner 3 of the opposed firing boiler. The bottom air nozzle 4 is made of high-temperature-resistant stainless steel.

As shown in fig. 2 and 3, the bottom air nozzle 4 is positioned between the lower layer cyclone burner 3 and the cold ash bucket 5 of the opposed firing boiler; the number of the bottom air nozzles 4 is consistent with that of the lower-layer cyclone burners 3 of the opposed firing boiler, and the bottom air nozzles 4 are positioned under the lower-layer cyclone burners 3 of the opposed firing boiler. The free end of the bottom air nozzle 4 extends into the interior of the opposed firing boiler.

As shown in fig. 4, in the conventional opposed firing method, the lower layer cyclone burner 3 is a pulverized coal burner and is located at the lowermost layer in the height direction of the multi-layer pulverized coal burner, and the lower layer cyclone burner 3 is composed of a pulverized coal nozzle 12, an inner secondary air nozzle 13 and an outer secondary air nozzle 14. The lower layer cyclone burner 3 mainly controls the pulverized coal airflow not to scour the cold ash bucket area by depending on the speed of the pulverized coal airflow at the nozzle of the lowest layer burner and the strength of the cyclone of secondary air. Because the speed of buggy air current, overgrate air whirl intensity are great to the buggy stability influence that catches fire, should guarantee at first that the buggy catches fire surely to burn during the regulation, and the means of regulation is limited, so the utility model discloses all set up the end wind that holds in the palm on front wall 1 and back wall 2 of hedging combustion boiler to solve regional high temperature corrosion of hedging combustion boiler cold ash bucket, slagging scorification problem, reduce boiler furnace slag combustible content, promote boiler thermal efficiency. When the opposed firing boiler operates, the bottom air nozzles 4 which are positioned under the lower layer cyclone burner 3 and above the upper folding point 6 of the cold ash bucket are in a commissioning state, hot air enters each bottom air nozzle 4 through the bottom air main pipe 7 through the bottom air connecting pipe 8 and then enters the hearth through the bottom air nozzles 4 by high-speed jet flow. When the lower layer cyclone burner is in tissue combustion, when the velocity of the pulverized coal airflow is low or the cyclone intensity of secondary air is high, pulverized coal particles are separated and fall, the pulverized coal airflow which is not completely burnt out flows to the lower part of the lower layer cyclone burner, namely a cold ash bucket area of a hearth, a bottom supporting air nozzle is positioned at a position 0.5-1.5 m above an upper folding point of the cold ash bucket, and the pulverized coal particles or the pulverized coal airflow are supported by high-speed bottom supporting air jet flow on one hand when flowing through the bottom supporting air nozzle, so that the pulverized coal particles which are not completely burnt out are prevented from falling to the cold ash bucket; on the other hand, the bottom supporting air provides oxygen required by the ignition of the pulverized coal particles, the combustion and the burnout of the pulverized coal particles are promoted, and the burnt fly ash is taken out of the hearth to be carried out on a tail flue of the boiler under the action of the negative pressure of the hearth. The arrangement of the bottom supporting air nozzles improves the reducing atmosphere at the wall-attached position of the water-cooled wall in the cold ash bucket area of the hearth, so that the problem of high-temperature corrosion of the water-cooled wall in the cold ash bucket area is prevented, and the slagging of the break point area on the cold ash bucket is effectively prevented; unburned coal powder particles are not easy to fall into the cold ash bucket, the content of slag combustible is reduced, the heat efficiency of the boiler is improved, and the economic operation of the boiler is facilitated. Generally, the vertical distance between the lower layer cyclone burner 3 of the opposed firing boiler and the upper break point 6 of the ash cooling bucket is 4 m-6 m. According to different unit capacity distances, the general 300MW unit is about 4m, the 600MW unit is about 5m, the 1000MW unit is about 5.5m, the bottom air nozzle 4 is located 0.5m ~ 1.5m above the upper break point 6 of the ash bucket, thereby the vertical distance between the bottom air nozzle 4 and the lower layer cyclone burner 3 is 2.5m ~ 4m, this vertical distance is close with the vertical distance between lower layer cyclone burner and the middle layer cyclone burner, the setting of the bottom air that holds in the palm can not influence the normal firing of lower layer cyclone burner, the burning, also can not increase the required oxygen volume of lower layer cyclone burner buggy initial stage that catches fire because of holding in the palm the setting of bottom air, thereby influence lower layer cyclone burner low nitrogen combustion effect.

The utility model discloses respectively set up the one deck under the lower floor's cyclone burner on traditional opposed firing boiler's front wall 1 and back wall 2 and hold in the palm the leeward spout, hold in the palm the leeward and be the direct current wind, its wind regime is got from the female pipe of hot primary air or combustor bellows, relies on the high-speed efflux of the high-speed jet of the leeward to hold in the palm the buggy granule that educes or the buggy air current that does not burn to the greatest extent, prevents that it from falling into the cold ash bucket region and causing cold ash bucket water-cooling wall high temperature corrosion or slagging scorification. The bottom air provides oxygen required by combustion and burnout for the separated coal dust particles, promotes the burnout of the coal dust, reduces the content of slag combustible, and improves the thermal efficiency of the boiler. The bottom air nozzles are arranged, so that the problems of high-temperature corrosion and slagging in the cold ash bucket area of the opposed combustion boiler are solved on the premise of not influencing pulverized coal airflow ignition and low-nitrogen combustion of the lower-layer cyclone combustor, the content of slag combustible is reduced, and the thermal efficiency of the boiler is improved.

The utility model also discloses an offset combustion boiler, including foretell end air system of holding in palm.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A bottom air supporting system of a hedging combustion boiler is characterized by comprising a plurality of bottom air supporting nozzles (4), a plurality of bottom air supporting connecting pipes (8) and a bottom air supporting main pipe (7);

the bottom supporting air nozzles (4) are communicated with the bottom supporting air connecting pipes (8) in a one-to-one correspondence manner;

the plurality of bottom supporting air connecting pipes (8) are communicated with the bottom supporting air main pipe (7);

the bottom supporting air nozzle (4) is positioned between a lower layer cyclone burner (3) and a cold ash hopper (5) of the opposed firing boiler;

and the free end of the bottom air supporting nozzle (4) extends into the opposed combustion boiler.

2. The bottom-supporting air system of the opposed firing boiler according to claim 1, wherein the free end of the bottom-supporting air main pipe (7) is communicated with the hot primary air main pipe or the burner wind box.

3. A bottom-draught system for a hedging combustion boiler according to claim 1, wherein the number of bottom-draught nozzles (4) is the same as the number of lower cyclone burners (3) of the hedging combustion boiler, and the bottom-draught nozzles (4) are located directly below the lower cyclone burners (3) of the hedging combustion boiler.

4. A bottom air supporting system of a hedging combustion boiler according to claim 1, characterized in that an electric regulating valve (9) is arranged on the bottom air supporting connecting pipe (8).

5. A bottom air system of a hedging combustion boiler according to claim 1, characterized in that an electric stop valve (10) is arranged on the bottom air connecting pipe (8).

6. A bottom air supporting system of a hedging combustion boiler according to claim 1, characterized in that the bottom air supporting connecting pipe (8) is provided with a non-metallic expansion joint (11).

7. The bottom-supporting air system of the opposed firing boiler according to claim 1, characterized in that the vertical distance between the bottom-supporting air nozzle (4) and the lower layer cyclone burner (3) of the opposed firing boiler is 2.5 m-4 m.

8. The bottom air supporting system of the opposed firing boiler according to claim 1, characterized in that the cross-sectional area of the bottom air supporting nozzle (4) is the same as the cross-sectional area of the pulverized coal nozzle (12) of the lower layer cyclone burner (3) of the opposed firing boiler.

9. The bottom-supporting air system of the opposed firing boiler according to claim 1, characterized in that the bottom-supporting air nozzle (4) is made of stainless steel.

10. A opposed firing boiler, comprising the bottom-supported air system of any one of claims 1 to 9.

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