Device for relieving high-temperature corrosion of water cooling wall

Abstract

The invention relates to the technical field of boilers, and discloses a device for relieving high-temperature corrosion of a water cooling wall, which is characterized in that primary air is introduced into a branch pipe from a main pipe; the multiple layers of branch pipes are connected with the branch pipes through adjusting valves respectively. The multiple layers of branch pipes are arranged on the water cooling wall; a plurality of fan-shaped nozzles are arranged on each branch pipe at intervals; and the plurality of fan-shaped nozzles spray primary air in different directions on the surface of the water cooling wall to form an air screen. The device for relieving the high-temperature corrosion of the water cooling wall has the advantages of an existing adherence air technology, and meanwhile the problem that an existing secondary air nozzle is blocked is solved. High primary air pressure is combined with uniform distribution in the fan-shaped nozzle through the adjusting valve, it is ensured that a small amount of primary air is used for uniformly covering the surface of the water cooling wall, the wall adhering oxygen amount of the water cooling wall is increased, generation of gas such as hydrogen sulfide and carbon monoxide is reduced, and then the high-temperature corrosion tendency of the water cooling wall is slowed down.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of boilers, in particular to a device for relieving high-temperature corrosion of water-cooled walls. BACKGROUND

[0002] Currently, in order to relieve the high-temperature corrosion of water-cooled walls under deep peak-shaving load, most power station boilers adopt offset air technology. This technology opens linear wall-attached air ports in the water-cooled wall area where high-temperature corrosion is prone to occur; or symmetrically arranges wall-attached air port arrays on the front and rear walls of the boiler, and uses direct blowing to send primary air or secondary air into the furnace. The above methods are all based on the principle that the combustion center of the furnace expands to press air to all directions, so as to increase the oxygen content around the water-cooled wall, so as to inhibit the generation of hydrogen sulfide and carbon monoxide and other gases, thereby relieving the high-temperature corrosion of the water-cooled wall.

[0003] The above-mentioned offset air technology has many problems in operation. Taking a opposed firing boiler as an example, wall-attached air ports are generally symmetrically arranged on the front and rear walls of the opposed firing boiler; when the opposed firing boiler is running, the wall-attached air forms front and rear collisions, and due to the air pressure gradient generated by the expansion of the combustion center, the oxygen content is increased. However, when the wall-attached air uses a secondary air source, due to the reduction of load, the secondary air pressure is low, and the risk of coking and blocking of the wall-attached air port is obviously increased; when the wall-attached air uses a primary air source, due to the characteristics of the primary air, such as rigidity, high flow rate and carrying of coal slag particles, the wall-attached air seriously affects the original combustion in the opposed firing boiler, increases the difficulty of operation regulation, and the wall-attached air may directly impact the water-cooled walls of the left and right walls, causing additional wear and thinning of the water-cooled walls. SUMMARY

[0004] Therefore, the present application provides a device for relieving high-temperature corrosion of water-cooled walls, so as to solve the problems that, for the existing offset air technology, when the wall-attached air uses a secondary air source, due to the reduction of load, the secondary air pressure is low, and the risk of coking and blocking of the wall-attached air port is obviously increased; when the wall-attached air uses a primary air source, due to the characteristics of the primary air, such as rigidity, high flow rate and carrying of coal slag particles, the wall-attached air seriously affects the original combustion in the boiler, increases the difficulty of operation regulation, and the wall-attached air may directly impact the water-cooled walls of the left and right walls, causing additional wear and thinning of the water-cooled walls.

[0005] The present application provides a device for relieving high-temperature corrosion of water-cooled walls, comprising:

[0006] The branch pipe is connected with the main pipe through a valve, and the branch pipe is adapted to introduce primary air from the main pipe;

[0007] The multi-layer branch pipes are connected with the branch pipe through the adjusting valves respectively, and are arranged on the water cooling wall; a plurality of fan-shaped nozzles are arranged on each branch pipe at intervals; and the plurality of fan-shaped nozzles are suitable for spraying the primary air to different directions on the surface of the water cooling wall to form an air screen. Beneficial effects: the device for relieving the high-temperature corrosion of the water cooling wall has the advantages of the existing wall-attached air technology, and solves the existing problem of the blockage of the secondary air nozzle. The higher primary air pressure is combined with the uniform distribution of the adjusting valve in the fan-shaped nozzle to ensure that the small amount of primary air uniformly covers the surface of the water cooling wall, improves the wall-attached oxygen content of the water cooling wall, reduces the generation of hydrogen sulfide and carbon monoxide, overcomes the problems of the primary air due to the rigidity, easy to wash the water cooling wall, difficult to adjust during operation, disturbance of the flow field in the boiler, and influence on combustion, and further slows down the high-temperature corrosion trend of the water cooling wall.

[0008] Optionally, the branch pipe adopts a wall bushing form to enter the water cooling wall area. Beneficial effects: the above technical solution is adopted, installation and replacement are facilitated, and installation is convenient and flexible.

[0009] Optionally, the wall bushing is fixed on the fin of the water cooling wall, and is sealed by refractory pouring material.

[0010] Optionally, the valve is a stop valve.

[0011] Optionally, the primary air is hot primary air output from an air preheater, and the hot primary air in the main pipe is output to the branch pipe and the coal mill.

[0012] Optionally, the adjusting valve is an electric adjusting valve.

[0013] Optionally, the adjusting valve is a pneumatic adjusting valve.

[0014] Optionally, the branch pipe is prevented from being inconsistent with the expansion of the furnace by additionally installing a flexible expansion joint. Beneficial effects: the above technical solution is adopted, and the expansion of the branch pipe and the furnace is prevented from being inconsistent.

[0015] Optionally, the branch pipe has three layers, which are an upper branch pipe, a middle branch pipe and a lower branch pipe; the upper branch pipe is connected with the branch pipe through a first adjusting valve; the middle branch pipe is connected with the branch pipe through a second adjusting valve; and the lower branch pipe is connected with the branch pipe through a third adjusting valve.

[0016] Optionally, a test hole is arranged on the water wall at a position corresponding to each branch pipe, and the concentration of carbon monoxide is measured through the test hole; when the concentration of carbon monoxide at the position corresponding to the branch pipe increases, the opening of the regulating valve corresponding to the branch pipe is adjusted to increase. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 The arrangement of the boiler system provided in the embodiments of the present application is shown schematically.

[0019] Explanation of reference signs:

[0020] 1, branch pipe; 2, main pipe; 3, valve; 4, fan-shaped nozzle; 5, air preheater; 6, flexible expansion joint; 7, upper branch pipe; 8, middle branch pipe; 9, lower branch pipe; 10, first regulating valve; 11, second regulating valve; 12, third regulating valve; 13, burner; 14, electric dust removal device; 15, desulfurization tower; 16, chimney. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] The current boiler adopts a low-nitrogen combustion system, and the main combustion zone is under-oxygen combustion, which increases the area of the water-cooled wall near the main burner region that is subject to high-temperature corrosion. In severe cases, it can cause the water-cooled wall to thin and burst, which seriously affects the safe operation of the boiler. Due to the above reasons, the present application proposes a device for alleviating high-temperature corrosion of the water-cooled wall.

[0023] As Figure 1The specific embodiment of the device for relieving high-temperature corrosion of water-cooled walls comprises a branch pipe 1 and a multi-layer branch pipe. The device for relieving high-temperature corrosion of water-cooled walls is particularly suitable for the low-nitrogen combustion technical transformation and the boiler of the power plant participating in deep peak regulation.

[0024] The branch pipe 1 is connected with the mother pipe 2 through a valve 3, and the branch pipe 1 is suitable for introducing the primary air from the mother pipe 2. The multi-layer branch pipe is connected with the branch pipe 1 through an adjusting valve respectively, and the multi-layer branch pipe is arranged on the water-cooled wall. A plurality of fan-shaped nozzles 4 are arranged on each branch pipe at intervals. The plurality of fan-shaped nozzles 4 are suitable for spraying the primary air to different directions on the surface of the water-cooled wall to form a wind screen. The adjusting valve can be a manual adjusting valve. The water-cooled wall in the present application is located in the main combustion area of the boiler. The technical scheme in the present application is improved on the basis of the existing boiler water-cooled wall anti-coking air. Specifically, the primary air can be introduced from the two sides of the primary air mother pipe 2 to the branch pipes 1 on the two sides. The present application utilizes the pressure of the primary air and the design of the fan-shaped nozzles 4 to increase the protection range of the surrounding water-cooled wall, greatly reduce the amount of primary air, and reduce the influence on the combustion in the boiler.

[0025] At low load of the boiler, the wind pressure of the secondary air is low, and the outlet wind speed of the fan-shaped nozzle 4 is low, which cannot play a protective role. The use of primary air can improve the outlet wind speed of the fan-shaped nozzle 4 and ensure the constancy. Regardless of the change of the load, the required air volume of the water-cooled wall protection area will not be affected.

[0026] The technical scheme in the present application utilizes a small amount of air through the design of the fan-shaped nozzles 4 at a certain angle to form high-temperature corrosion protection for more water-cooled wall surfaces, which can also solve the problems of the influence of high-speed wall-attached air on the combustion in the boiler and wear and tear.

[0027] Specifically, the branch pipe adopts a wall bushing form to enter the water-cooled wall area, the outside of the wall bushing is fixed on the fin of the water-cooled wall, and the wall bushing is sealed by refractory cast material.

[0028] Specifically, the valve 3 is a stop valve. The stop valve can be a manual stop valve. The stop valve can be an electric stop valve or a pneumatic stop valve.

[0029] Specifically, the primary air is hot primary air output from an air preheater 5, and the hot primary air in the mother pipe 2 is output to the branch pipe 1 and a coal mill, as indicated by the downward arrow, that is, output to the coal mill. Figure 1

[0030] Specifically, the adjusting valve is an electric adjusting valve or a pneumatic adjusting valve. The adjusting valve adjusts the required air volume according to the actual situation to play a role in relieving the high-temperature corrosion of the water-cooled wall. The adjusting valve can adopt the minimum air volume valve opening to ensure that the fan-shaped nozzle 4 has a cooling air volume for cooling. The adjusting valve can flexibly adjust the air volume of each layer according to the required actual air volume.​

[0031] Furthermore, the branch pipe 1 is equipped with a flexible expansion joint 6 to prevent the branch pipe 1 from expanding inconsistently with the furnace.

[0032] Specifically, the branch pipe has three layers: an upper branch pipe 7, a middle branch pipe 8, and a lower branch pipe 9. The upper branch pipe 7 is connected to the branch pipe 1 through a first regulating valve 10. The middle branch pipe 8 is connected to the branch pipe 1 through a second regulating valve 11. The lower branch pipe 9 is connected to the branch pipe 1 through a third regulating valve 12.

[0033] Furthermore, test holes are provided on the water-cooled wall at the positions corresponding to each branch pipe, and the concentration of carbon monoxide can be measured through the test holes; when the concentration of carbon monoxide at the corresponding branch pipe increases, the opening of the regulating valve corresponding to the above-mentioned branch pipe is adjusted to increase.

[0034] This technical solution utilizes an added pipeline to draw high-pressure hot primary air to a fan-shaped nozzle 4, employing the principle of angled spraying to create an oxygen-rich air barrier within the protected water-cooled wall area. This solution combines the advantages of existing wall-mounted air systems, enabling the directional and orderly use of hot primary air to increase the protection area of ​​the water-cooled wall and mitigate high-temperature corrosion. It also addresses the impact of high-speed wall-mounted air on boiler combustion, requires less hot primary air, and offers flexible adjustment during operation.

[0035] like Figure 1 The boiler system shown includes: the device for mitigating high-temperature corrosion of the water-cooled walls, a burner 13, an electrostatic precipitator 14, a desulfurization tower 15, and a chimney 16. The burner 13 can be the main burner. Water-cooled walls are provided around the burner 13. The electrostatic precipitator 14 is connected to the burner 13; the electrostatic precipitator 14 is adapted to remove dust from the flue gas generated during combustion within the burner 13. The desulfurization tower 15 is connected to the electrostatic precipitator 14, and the desulfurization tower 15 is adapted to desulfurize the dust-removed flue gas. The chimney 16 is connected to the desulfurization tower 15, and the chimney 16 is adapted to discharge the desulfurized flue gas.

[0036] When the boiler system starts up, valve 3 on the branch pipe is opened, as are the first regulating valve 10, the second regulating valve 11, and the third regulating valve 12. Hot primary air enters the fan-shaped nozzle 4 through the wall-penetrating pipe. Utilizing the pressure of the primary air and the arrangement of the fan-shaped nozzle 4, it then enters the boiler furnace, forming an air screen on the surface of the water-cooled wall. This reduces the concentration of carbon monoxide in the water-cooled wall area and slows down the occurrence of high-temperature corrosion of the water-cooled wall.

[0037] While embodiments of the application have been described in connection with the preferred embodiments of the various figures, those of ordinary skill in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the application, and that such modifications and changes fall within the scope of the appended claims.

Claims

1. A device for mitigating high-temperature corrosion of water-cooled walls, characterized in that, include: A branch pipe (1) is connected to the main pipe (2) via a valve (3), and the branch pipe (1) is adapted to introduce primary air from the main pipe (2); Multi-layer branch pipes are connected to the branch pipes (1) through regulating valves; and the multi-layer branch pipes are set on the water-cooled wall; multiple fan-shaped nozzles (4) are spaced apart on each branch pipe; the multiple fan-shaped nozzles (4) are suitable for spraying primary air in different directions on the surface of the water-cooled wall to form an air screen.

2. The device for mitigating high-temperature corrosion of water-cooled walls according to claim 1, characterized in that, The branch pipe enters the water-cooled wall area through a wall sleeve.

3. The device for mitigating high-temperature corrosion of water-cooled walls according to claim 2, characterized in that, The external of the through-wall sleeve is fixed to the fins of the water-cooled wall and sealed with refractory castable.

4. The device for mitigating high-temperature corrosion of water-cooled walls according to claim 1, characterized in that, The valve (3) is a shut-off valve.

5. The device for mitigating high-temperature corrosion of water-cooled walls according to claim 1, characterized in that, The primary air is hot primary air output from the air preheater (5), and the hot primary air in the main pipe (2) is output to the branch pipe (1) and the coal mill.

6. The device for mitigating high-temperature corrosion of water-cooled walls according to claim 1, characterized in that, The regulating valve is an electric regulating valve.

7. The device for mitigating high-temperature corrosion of water-cooled walls according to claim 1, characterized in that, The regulating valve is a pneumatic regulating valve.

8. The device for mitigating high-temperature corrosion of water-cooled walls according to claim 1, characterized in that, The branch pipe (1) is equipped with a flexible expansion joint (6) to prevent the branch pipe (1) from expanding inconsistently with the furnace.

9. The apparatus for mitigating high-temperature corrosion of water-cooled walls according to any one of claims 1-8, characterized in that, The branch pipe has three layers: an upper branch pipe (7), a middle branch pipe (8), and a lower branch pipe (9). The upper branch pipe (7) is connected to the branch pipe (1) through a first regulating valve (10). The middle branch pipe (8) is connected to the branch pipe (1) through a second regulating valve (11). The lower branch pipe (9) is connected to the branch pipe (1) through a third regulating valve (12).

10. The apparatus for mitigating high-temperature corrosion of water-cooled walls according to any one of claims 1-8, characterized in that, Test holes are provided on the water-cooled wall at the positions corresponding to each branch pipe. The concentration of carbon monoxide can be measured through the test holes. When the concentration of carbon monoxide at the corresponding branch pipe increases, the opening of the regulating valve for the corresponding branch pipe is adjusted to increase.

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