Opposed firing boiler, control method and side wall water wall skin atmosphere improvement system

Abstract

The application belongs to a reducing atmosphere improvement method, and aims at the technical problems of low protection effect, high cost and low efficiency of the measures for relieving high-temperature corrosion of water-cooled walls, and provides a counter-burning boiler, a control method and a side wall water-cooled wall atmosphere improvement system. The side wall water-cooled wall atmosphere is collected through a water-cooled wall atmosphere measuring device, the pulverized coal concentration of two branch pipes of a primary pulverized coal pipe is adjusted through a pulverized coal concentration adjusting device, and after the side wall water-cooled wall atmosphere detected by the water-cooled wall atmosphere measuring device is acquired by a controller, the pulverized coal concentration in the two branch pipes of the primary pulverized coal pipe is controlled according to the side wall water-cooled wall atmosphere, and the secondary air quantity and the swirling intensity in the burner are adjusted, so that the reducing atmosphere of the side wall water-cooled wall meets the preset requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to a reducing atmosphere improvement method, and particularly relates to a system for improving the atmosphere of a side wall water cooled wall of a wall-opposed combustion boiler, a control method and a wall-opposed combustion boiler. BACKGROUND

[0002] In a front and back wall wall-opposed combustion system, the burners are arranged on the front wall and the back wall of the boiler, which causes serious high-temperature corrosion of the side wall water cooled wall. The high-temperature corrosion can cause the water cooled wall to be thinned, the metal strength to be reduced, and the corrosion products to accelerate the expansion of transverse cracks under the action of alternating thermal stress, which greatly increases the risk of water cooled wall tube burst, causes the unit to be unplanned to be shut down, and seriously threatens the safe and stable operation of the unit.

[0003] At present, the measures for relieving the high-temperature corrosion of the water cooled wall mainly include water cooled wall corrosion prevention spraying and wall-attached air technology. Among them, the water cooled wall corrosion prevention spraying belongs to passive protection, can only be carried out during maintenance, has high cost, and the poor spraying quality can easily cause the spraying to fall off, which greatly reduces the protection of the water cooled wall; the wall-attached air technology has an actual application effect that is not ideal due to the insufficient momentum of the sent air and the low air pressure, and the wall-attached air has a certain influence on the boiler efficiency. SUMMARY

[0004] The application aims at the technical problems of low protection effect, high cost and low efficiency of the current measures for relieving the high-temperature corrosion of the water cooled wall, and provides a system for improving the atmosphere of a side wall water cooled wall of a wall-opposed combustion boiler, a control method and a wall-opposed combustion boiler.

[0005] In order to achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0006] In a first aspect, the application provides a system for improving the atmosphere of a side wall water cooled wall of a wall-opposed combustion boiler, which comprises a controller, and a plurality of water cooled wall atmosphere measuring devices and a plurality of pulverized coal concentration adjusting devices connected to the controller;

[0007] The controller is further used to connect a plurality of burners located on the front wall and the back wall;

[0008] The plurality of water cooled wall atmosphere measuring devices are symmetrically arranged on the left wall and the right wall respectively, and are used to measure the atmosphere of the side wall water cooled wall;

[0009] The inlet of the plurality of pulverized coal concentration adjusting devices is used to connect the main pipe of the primary pulverized pipe, and the outlet is used to connect two branch pipes of the primary pulverized pipe; wherein the pulverized coal concentration in the two branch pipes of the primary pulverized pipe is different;

[0010] The controller is used to acquire the side wall water cooling wall adhering atmosphere detected by the water cooling wall adhering atmosphere measuring device, and control the pulverized coal concentration in the two branches of the primary pulverized coal pipe according to the side wall water cooling wall adhering atmosphere, and adjust the secondary air volume and the rotational flow intensity in the burner, so that the reducing adhering atmosphere at the side wall water cooling wall meets the preset requirement.

[0011] Further, the pulverized coal concentration adjusting device adopts the thick-thin separation mode of the louvered inertial separation, and is used to adjust the pulverized coal concentration in the two branches of the primary pulverized coal pipe.

[0012] Further, the water cooling wall adhering atmosphere measuring device is arranged on the left wall and the right wall in 2-3 layers, and adopts the measuring mode of the laser method or the electrochemical method.

[0013] Further, the side wall water cooling wall adhering atmosphere includes the concentrations of O2, H2S and CO.

[0014] In the second aspect, the application provides an opposed firing boiler, which includes a front wall, a back wall, a left wall, a right wall, a primary pulverized coal pipe and a burner, and further includes the opposed firing boiler side wall water cooling wall adhering atmosphere improving system.

[0015] Further, the inlet of the primary pulverized coal pipe is connected with the outlet of the coal mill.

[0016] Further, the coal mill is a medium-speed coal mill or a double-inlet and double-outlet steel ball coal mill.

[0017] Further, the burner is a rotational flow burner.

[0018] In the third aspect, the application provides a control method of the opposed firing boiler, which includes:

[0019] If the O2 concentration in the side wall water cooling wall adhering atmosphere is greater than or equal to the first preset value and the CO concentration is less than the second preset value, no adjustment is performed.

[0020] If the O2 concentration in the side wall water cooling wall adhering atmosphere is greater than or equal to the third preset value and the H2S concentration is greater than or equal to the fourth preset value, the controller is used to control the pulverized coal concentration adjusting device, so that the pulverized coal concentration in the burner close to the side wall water cooling wall is reduced, the pulverized coal concentration in the burner far away from the side wall water cooling wall is increased, the secondary air volume in the burner is increased, the rotational flow intensity in the burner close to the side wall water cooling wall is reduced, and the rotational flow intensity in the burner far away from the side wall water cooling wall is increased.

[0021] Further, the first preset value is 1%, the second preset value is 0.1%, the third preset value is 0.1%, and the fourth preset value is 0.01%.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] Further, the first preset value is 1%, the second preset value is 0.1%, the third preset value is 0.1%, and the fourth preset value is 0.01%.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] The application provides a system for improving the atmosphere of a side wall water cooled wall of a opposed firing boiler, which collects the atmosphere of the side wall water cooled wall through a water cooled wall atmosphere measuring device, adjusts the pulverized coal concentration of two branch pipes of a primary pulverized coal pipe through a pulverized coal concentration adjusting device, and controls the pulverized coal concentration in the two branch pipes of the primary pulverized coal pipe and adjusts the secondary air volume and the cyclone intensity in the burner according to the atmosphere of the side wall water cooled wall after the controller obtains the atmosphere of the side wall water cooled wall detected by the water cooled wall atmosphere measuring device, so that the reducing atmosphere of the side wall water cooled wall meets the preset requirements. The uneven pulverized coal concentration distribution mode is adopted, the primary pulverized coal pipe is divided into two parts through the pulverized coal concentration adjustment, the pulverized coal concentration near the burner of the side wall water cooled wall is reduced, the pulverized coal concentration away from the burner of the side wall water cooled wall is increased, the secondary air volume near the burner of the side wall water cooled wall is increased, the reducing atmosphere of the side wall water cooled wall is improved, the high-temperature corrosion problem of the side wall water cooled wall is solved, the protection effect is obvious, the controller can be used for real-time adjustment, the efficiency is extremely high, and the cost is low.

[0024] The application also provides an opposed firing boiler and a control method thereof, which have all the advantages of the system for improving the atmosphere of a side wall water cooled wall of an opposed firing boiler. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0026] Figure 1 FIG. 2 is a schematic diagram of a second embodiment of the system for improving the atmosphere of a side wall water cooled wall of an opposed firing boiler according to the application.

[0027] Figure 1 In the figure, 1 is a controller, 2 is a water cooled wall atmosphere measuring device, 3 is a burner, and 4 is a primary pulverized coal pipe. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the following will combine the drawings in the embodiments of the application to clearly and completely describe the technical solutions in the embodiments of the application. Obviously, the described embodiments are some of the embodiments of the application, but not all the embodiments. The components of the embodiments of the application described and shown in the drawings can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] Front and rear wall opposed combustion systems are commonly used in large-capacity boilers. This system is a widely applied combustion technology in large coal-fired boilers, characterized by burners positioned on the front and rear walls of the boiler, forming an opposed combustion layout. Utilizing an induced draft fan, the airflow from the burner outlets forms a predominantly upward airflow in the center of the furnace. This layout helps improve the boiler's combustion and thermal efficiency while reducing pollutant emissions. The main combustion process is as follows: After being prepared by the pulverizing system, pulverized coal is fed into the burners by a primary air fan. The primary air carries the pulverized coal into the furnace for initial combustion. Secondary air enters through secondary air ducts into large, separate air boxes located on the front and rear walls of the spiral furnace. The high-temperature, high-speed secondary air mixes with the primary air and pulverized coal, creating a strong combustion reaction. The airflows from the burner outlets on the front and rear walls meet and mix in the center of the furnace, forming opposed combustion. Some particles, after being opposed, tend to move upwards and exit from the furnace outlet, while others may move downwards and fall into the cold ash hopper area.

[0035] This combustion method typically employs a swirl burner, which contains various types of swirl generators. When the pulverized coal gas flow or hot air passes through the swirl generator, it rotates and is ejected from the burner nozzle to form a rotating jet. This creates a high-temperature flue gas recirculation zone that is conducive to ignition and causes strong mixing of the gas flow, thereby improving the stability of combustion. Each burner acts as an independent combustion torch, with minimal mutual influence.

[0036] In a front and rear wall opposed combustion system, the burners are arranged on the front and rear walls of the boiler. After the pulverized coal particles exit the burner nozzles, in addition to flowing vertically upwards, they also diffuse to both sides. The airflow to both sides causes the pulverized coal particles to collide with the side walls. Due to the collision with the wall and their own retention characteristics, the pulverized coal particles accumulate in the area near the wall. The increased concentration of pulverized coal particles in the side wall area leads to a decrease in the oxygen content of the side wall, creating a reducing atmosphere and causing high-temperature corrosion of the water-cooled wall. For front and rear wall opposed combustion boilers, high-temperature corrosion of the side wall water-cooled wall is particularly severe.

[0037] In view of the above situation, this application proposes a counter-fired boiler, a control method, and a sidewall water-cooled wall atmosphere improvement system. The following describes this application in detail with reference to the embodiments and accompanying drawings.

[0038] As a first embodiment of the system for improving the wall atmosphere of the water-cooled wall of a counter-fired boiler, this application may include a controller 1, and several water-cooled wall atmosphere measuring devices 2 and several pulverized coal concentration regulating devices respectively connected to the controller 1.

[0039] The controller 1 is also used to connect several burners 3 located on the front and rear walls, and can control the secondary air volume and swirl intensity in the burners 3.

[0040] Several water-cooled wall atmosphere measuring devices 2 are symmetrically arranged on the left and right walls to measure the atmosphere attached to the sidewall water-cooled walls. In practical applications, the atmosphere attached to the sidewall water-cooled walls may include the concentrations of oxygen, carbon monoxide, carbon dioxide, sulfur dioxide, etc. Because the temperature field and atmosphere distribution near the water-cooled wall directly affect its heat load and cooling effect, monitoring can help detect and address potential local overheating problems in a timely manner, preventing damage to the water-cooled wall.

[0041] In practical applications, the water-cooled wall atmosphere measurement device 2 is typically installed near the boiler's water-cooled wall. A sampling probe penetrates deep into the furnace to collect and analyze the gas composition in the water-cooled wall's contact zone in real time. During setup, the sampling probes can be arranged in a pre-defined grid pattern within the furnace, targeting areas prone to high-temperature corrosion, to ensure comprehensive and accurate monitoring. The water-cooled wall atmosphere measurement device 2 is widely used in coal-fired boilers and is crucial for improving boiler operational safety, preventing high-temperature corrosion, and optimizing the combustion process. By monitoring the gas composition and atmosphere in the water-cooled wall's contact zone in real time, operators can promptly identify potential problems and take corrective measures, thereby ensuring the long-term stable operation of the boiler.

[0042] The inlet of several pulverized coal concentration regulating devices is used to connect to the main pipe of the primary pulverized coal pipe 4, and the outlet is used to connect to the two branch pipes of the primary pulverized coal pipe 4; wherein the pulverized coal concentrations in the two branch pipes of the primary pulverized coal pipe 4 are different.

[0043] It should be noted that the primary pulverized coal pipe 4 is the main channel for conveying pulverized coal from the pulverizing system to the burner 3. It is typically responsible for mixing the pulverized coal ground by the coal mill with primary air (i.e., the air used to transport the pulverized coal) and then delivering it to the boiler burner 3 for combustion. The pulverized coal concentration regulating device installed on the primary pulverized coal pipe 4 can adjust the pulverized coal concentration in the two branch pipes of the primary pulverized coal pipe 4, making the pulverized coal concentration controllable for the burner 3 near and away from the sidewall water-cooled wall.

[0044] In addition, the coal powder concentration regulating device installed on the primary coal pipe 4 mainly functions to regulate and control the concentration of coal powder in the primary air. It can usually be composed of components such as rotary separators, regulating valves, and actuators, and the concentration can be regulated by changing the flow rate, velocity, or direction of the coal powder flow.

[0045] In practical applications, the specific data and arrangement of the water-cooled wall atmosphere measuring device 2 and the pulverized coal concentration regulating device can be adjusted according to the needs of use, and this application does not impose specific restrictions.

[0046] The controller 1 is used to acquire the side wall water-cooled wall atmosphere detected by the water-cooled wall atmosphere measuring device 2, and control the coal powder concentration in the two branch pipes of the primary coal pipe 4 according to the side wall water-cooled wall atmosphere, and adjust the secondary air volume and swirl intensity in the burner 3 so that the reducing wall atmosphere at the side wall water-cooled wall meets the preset requirements.

[0047] like Figure 1 As shown, this is a second embodiment of a system for improving the wall atmosphere of a water-cooled sidewall of a counter-fired boiler according to this application. It may include two controllers 1, and eight water-cooled wall atmosphere measuring devices 2 and eight dry coal powder concentration regulating devices connected to the controllers 1 respectively.

[0048] Eight water-cooled wall atmosphere measuring devices 2 are installed on the left and right walls, respectively. Four devices are installed on the left wall and four on the right wall. Eight pulverized coal concentration regulating devices are installed on the front and rear walls, respectively. Four devices are installed on the front wall (denoted as A1 to A4) and four on the rear wall (denoted as B1 to B4). Correspondingly, four primary pulverized coal pipes 4 are installed on one side of the front wall and four on one side of the rear wall.

[0049] In addition, this embodiment is equipped with two controllers 1, which are respectively connected to the water-cooled wall atmosphere measuring device 2 on the left side of the wall and the water-cooled wall atmosphere measuring device 2 on the right side of the wall. They are also respectively connected to the coal powder concentration regulating devices near the left wall and the right wall of the front and rear walls, so as to realize independent control of the left and right walls and make the control effect more precise.

[0050] Corresponding to the offset combustion boiler sidewall water-cooled wall atmosphere improvement system, this application also proposes an offset combustion boiler including the above-mentioned offset combustion boiler sidewall water-cooled wall atmosphere improvement system. Specifically, an embodiment of the above-mentioned offset combustion boiler sidewall water-cooled wall atmosphere improvement system can be adopted. The following is a specific example of an offset combustion boiler to further illustrate this application:

[0051] Burner 3 is a swirl burner 3, which includes a central air duct, a primary air duct, a secondary air duct, and a tertiary air duct. Correspondingly, the central and primary air are direct jets, while the secondary and tertiary air are swirl jets. Burners 3 can be arranged in 2-3 layers on the front and rear walls of the boiler, with 4 or 8 burner nozzles on each layer. The burners 3 on the front and rear walls are arranged opposite each other at the same elevation. The primary pulverized coal pipe 4 connects to the outlet of the coal mill. The coal mill is a medium-speed coal mill or a double-inlet, double-outlet ball mill. The pulverized coal concentration regulating device is located on the primary pulverized coal pipe 4, which splits into two branches after passing through the device. The pulverized coal concentration regulating device has its inlet connected to the main pipe of the primary pulverized coal pipe 4 and its outlet connected to two branch pipes of the primary pulverized coal pipe 4. It is used to regulate the pulverized coal concentration in the branch pipes of the two primary pulverized coal pipes 4. The pulverized coal concentration regulating device can adopt a louvered inertial separation method to separate the pulverized coal into two streams of concentrated and diluted pulverized coal, which are then sent to the corresponding burners 3 through different branch pipes. The angle of the louvers can be adjusted within the range of 0°-90° via an electric actuator. The water-cooled wall atmosphere measuring device 2 is arranged on the left and right walls of the boiler, with 2-3 layers corresponding to the burners 3 at the same elevation. A measuring point can be placed every 2-3 meters according to the length of the boiler sidewall. Specifically, laser or electrochemical methods are used to measure the water-cooled wall atmosphere. As an example, the detected gases mainly include O2, H2S, and CO, and the water-cooled wall atmosphere of the entire burner 3 area is monitored in real time. The controller 1 is used to receive the O2, H2S, and CO concentration signals measured by the water-cooled wall atmosphere measuring device 2, and adjust the pulverized coal concentration regulating device according to the O2, H2S, and CO concentrations to change the pulverized coal concentration of the burner 3 near the side wall water-cooled wall, and adjust the secondary / tertiary air volume and swirl intensity, thereby improving the reducing atmosphere near the side wall water-cooled wall.

[0052] Corresponding to the aforementioned counter-firing boiler, this application also proposes a control method for a counter-firing boiler, which may include:

[0053] If the O2 concentration in the atmosphere attached to the water-cooled sidewall is greater than or equal to the first preset value and the CO concentration is less than the second preset value, no adjustment will be made.

[0054] If the O2 concentration in the atmosphere attached to the side wall water-cooled wall is greater than or equal to the third preset value and the H2S concentration is greater than or equal to the fourth preset value, the pulverized coal concentration regulating device is controlled by the controller 1 to reduce the pulverized coal concentration in the burner 3 near the side wall water-cooled wall and increase the pulverized coal concentration in the burner 3 far from the side wall water-cooled wall, and increase the secondary air volume in the burner 3, thereby reducing the swirl intensity in the burner 3 near the side wall water-cooled wall and increasing the swirl intensity in the burner 3 far from the side wall water-cooled wall.

[0055] As an example of the control method: The concentration signals of O2, H2S, and CO measured by the water-cooled wall atmosphere measuring device 2 are input into the controller 1. When 1% ≤ O2 and CO < 0.1%, the reducing atmosphere in the water-cooled wall area of ​​the boiler side wall is very weak, and the risk of high-temperature corrosion is low. The pulverized coal concentration regulating device, the secondary / tertiary air volume and swirl intensity of the burner 3 are not adjusted. When 0.1% ≤ CO and 0.01% ≤ H2S, the controller 1 adjusts the louver angle of the pulverized coal concentration regulating device to increase the intensity of pulverized coal inertial separation, reduce the pulverized coal concentration of the burner 3 near the water-cooled wall, increase the pulverized coal concentration of the burner 3 far from the water-cooled wall, and increase the secondary air volume of the corresponding burner 3 to reduce the swirl intensity of the burner 3 near the water-cooled wall and increase the swirl intensity of the burner 3 far from the water-cooled wall, thereby improving the reducing atmosphere near the water-cooled wall and preventing high-temperature corrosion. The adjustment of the pulverized coal concentration regulating device, the secondary / tertiary air volume and swirl intensity of burner 3 are carried out in a one-to-one correspondence manner. For example, if the reducing wall-adhering atmosphere is strong in the area between the left wall and the front wall, the pulverized coal concentration regulating device and burner 3 of the A1 pulverized coal pipe are adjusted accordingly.

[0056] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A system for improving the wall atmosphere of a counter-firing boiler sidewall water-cooled wall, characterized in that, It includes a controller (1), and several water-cooled wall-mounted atmosphere measuring devices (2) and several pulverized coal concentration regulating devices respectively connected to the controller (1); The controller (1) is also used to connect several burners (3) located on the front wall and the rear wall; Several water-cooled wall-mounted atmosphere measuring devices (2) are symmetrically arranged on the left and right walls respectively, for measuring the side wall water-cooled wall-mounted atmosphere; the side wall water-cooled wall-mounted atmosphere includes the concentrations of O2, H2S and CO; The inlet of several coal powder concentration regulating devices is used to connect to the main pipe of the primary coal powder pipe (4), and the outlet is used to connect to the two branch pipes of the primary coal powder pipe (4); wherein the coal powder concentrations in the two branch pipes of the primary coal powder pipe (4) are different. The controller (1) is used to acquire the side wall water-cooled wall atmosphere detected by the water-cooled wall atmosphere measuring device (2), and according to the side wall water-cooled wall atmosphere, control the coal powder concentration in the two branch pipes of the primary coal pipe (4), and adjust the secondary air volume and swirl intensity of the burner (3) so that the side wall water-cooled wall atmosphere meets the preset requirements: If the O2 concentration in the atmosphere attached to the water-cooled sidewall is greater than or equal to the first preset value and the CO concentration is less than the second preset value, no adjustment will be made. If the O2 concentration in the atmosphere attached to the side wall water-cooled wall is greater than or equal to the third preset value and the H2S concentration is greater than or equal to the fourth preset value, the pulverized coal concentration adjustment device is controlled by the controller (1) to reduce the pulverized coal concentration in the burner (3) close to the side wall water-cooled wall and increase the pulverized coal concentration in the burner (3) far from the side wall water-cooled wall, and increase the secondary air volume of the burner (3), reduce the swirl intensity in the burner (3) close to the side wall water-cooled wall, and increase the swirl intensity in the burner (3) far from the side wall water-cooled wall.

2. The system for improving the wall atmosphere of the water-cooled sidewall of a counter-firing boiler according to claim 1, characterized in that, The coal powder concentration regulating device adopts a louvered inertial separation method for concentration separation, which is used to regulate the coal powder concentration in the two branch pipes of the primary coal pipe (4).

3. The system for improving the wall atmosphere of the water-cooled sidewall of a counter-firing boiler according to claim 2, characterized in that: Several water-cooled wall-mounted atmosphere measuring devices (2) are arranged in 2-3 layers on the left and right walls, and the measurement method is laser or electrochemical.

4. A counter-firing boiler, comprising a front wall, a rear wall, a left wall, a right wall, a primary pulverized coal tube (4), and a burner (3); characterized in that: It also includes the offset combustion boiler sidewall water-cooled wall atmosphere improvement system as described in any one of claims 1 to 3.

5. The opposed-fired boiler according to claim 4, characterized in that: The inlet of the primary pulverizing pipe (4) is connected to the outlet of the coal mill.

6. The opposed-fired boiler according to claim 5, characterized in that: The coal mill is a medium-speed coal mill or a double-inlet double-outlet ball mill.

7. The opposed-fired boiler according to claim 6, characterized in that: The burner (3) is a swirl burner (3).

8. The opposed-fired boiler according to claim 7, characterized in that, First preset value The first preset value is 1%, the second preset value is 0.1%, the third preset value is 0.1%, and the fourth preset value is 0.01%.

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