Opposite firing boiler and using method thereof

Abstract

The invention discloses an opposed firing boiler and a using method thereof. The opposed firing boiler comprises a boiler body, a control unit and a monitoring unit. The front wall and the rear wall of the boiler body are each provided with a turbulent burner module, the two sides of each turbulent burner module are each provided with a direct-current burner module, and the direct-current burner modules are arranged close to the left wall and the right wall of the boiler body; a middle coal pulverizing system set is connected to the turbulent burner module, a wall-attached coal pulverizing system is connected to the direct-current burner module, a pulverized coal concentration adjusting assembly is arranged between the direct-current burner module and the wall-attached coal pulverizing system, and a wall-attached primary air adjusting assembly is further arranged on the direct-current burner module. The pulverized coal concentration adjusting assembly and the wall-attached primary air adjusting assembly both communicate with the control unit, and the monitoring unit is arranged close to the left wall or the right wall of the boiler body and communicates with the control unit. The device can effectively reduce the corrosion condition of the pipe wall of the water cooling wall, and improves the operation safety of the opposed firing boiler.

Description

Technical Field

[0001] The invention belongs to the technical field of boiler combustion, and relates to a counter-combustion boiler and a use method thereof. Background Art

[0002] High-temperature corrosion of boiler heating surfaces is a phenomenon in which corrosive elements such as sulfur in the fuel generate corrosive ash layers and corrosive atmospheres during the combustion process, causing the surface of the metal tubes of the high-temperature heating surface to be corroded. With the application of low-nitrogen combustion technology, the reducing atmosphere in the near-wall area of ​​the water-cooled wall in the main combustion zone has increased significantly, resulting in the problem of accelerated high-temperature corrosion rate in the area below the burnout wind. For opposed-combustion boilers, when the sulfur content of the coal entering the furnace is high, the water-cooled walls on both sides are the most prominent areas of high-temperature corrosion. To address this problem, there are currently two measures, active protection and passive protection. For active protection, reducing the reducing atmosphere in the near-wall area of ​​the water-cooled walls on both sides is the key. Currently, there are technologies such as wall-attached wind and inward adjustment of the jet angle of the burners on both sides; for passive protection, there is currently water-cooled wall surface spraying technology.

[0003] The wall-mounted wind nozzles can improve the reducing atmosphere in the near-wall area of ​​the two side walls, but the increase in the wall-mounted wind may lead to a reduction in the organized secondary air involved in the combustion of the burner, and improper design may have an adverse effect on the combustion stability. After the jet angle of the burners on both sides is adjusted and modified, the direct scouring of the water-cooled wall by the primary air pulverized coal airflow of the burners on both sides can be improved, thereby improving the reducing atmosphere in the near-wall area. However, this modification method is limited in its promotion and application due to the large workload (primary air duct modification, water-cooled wall pipe modification) and limited rotation angle. Water-cooled wall surface spraying, as a passive protection technology, is an effective way to prevent high-temperature corrosion of the water-cooled wall, but this technology has limitations due to the sandblasting process, spraying process, spraying materials, maintenance costs, etc. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a device and method for controlling the high-temperature corrosion rate of the water-cooled wall on the side walls of a counter-firing boiler, thereby solving the technical problem of poor high-temperature corrosion mitigation performance of the water-cooled wall on both side walls of a counter-firing boiler in the prior art.

[0005] The present invention is achieved through the following technical solutions:

[0006] A counter-combustion boiler comprises a boiler body, a control unit and a monitoring unit; a swirl burner module is provided on the front wall and the rear wall of the boiler body, a direct current burner module is provided on both sides of the swirl burner module, and the direct current burner modules are arranged close to the left wall and the right wall of the boiler body;

[0007] The swirl burner module is connected to a middle pulverizing system group, the DC burner module is connected to a wall-attached pulverizing system, a pulverized coal concentration adjustment component is provided between the DC burner module and the wall-attached pulverizing system, and the DC burner module is also provided with a wall-attached primary air adjustment component;

[0008] The pulverized coal concentration regulating component and the wall-attached primary air regulating component both communicate with the control unit. The monitoring unit is disposed close to the left wall or the right wall of the boiler body and communicates with the control unit.

[0009] Preferably, the swirl burner module comprises a plurality of groups of swirl burner assemblies arranged in parallel, any group of the swirl burner assemblies is connected to a central milling system, and a plurality of the central milling systems constitute the central milling system group.

[0010] Preferably, the swirl burner assemblies are in 2 to 4 groups, and each group includes 4 to 6 swirl burners.

[0011] Preferably, the DC burner module includes a plurality of DC burners, and the DC burners are connected to the wall-adherent powder making system.

[0012] Preferably, the number of DC burners in a DC burner module is not less than the number of groups of swirl burner assemblies.

[0013] Preferably, the opposed-combustion boiler further comprises a plurality of powder delivery pipes, and a plurality of the direct-current burners are respectively connected to the wall-attached powder making system via the plurality of the powder delivery pipes; and the pulverized coal concentration regulating component is provided on any one of the powder delivery pipes.

[0014] Preferably, the direct current burner comprises a first nozzle and a second nozzle, the first nozzle being arranged close to the side wall of the boiler body; when in use, the concentration of the coal powder in the first nozzle is lower than the concentration of the coal powder in the second nozzle.

[0015] Preferably, the wall-attached primary air regulating component includes a wall-attached hot primary air regulating valve and a wall-attached cold primary air regulating valve.

[0016] The above-mentioned method for using the counter-fired boiler uses the monitoring unit to obtain the smoke components of the left wall and the right wall close to the boiler body, and feeds the data back to the control unit;

[0017] When the wall-attached pulverizing system is in operation, the control unit adjusts the pulverized coal concentration adjustment component and the wall-attached primary air adjustment component to make the flue gas composition on the side wall of the boiler body meet the operating requirements. When the wall-attached pulverizing system is shut down, the wall-attached primary air adjustment component is used to make the flue gas composition on the side wall of the boiler body meet the operating requirements.

[0018] Preferably, when the unit load is below 80%, the wall-attached pulverizing system is shut down, and the DC burner module only delivers hot primary air as wall-attached air.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The present invention discloses a counter-combustion boiler. First, swirl burner modules are arranged on the front wall and the rear wall of the boiler body, and DC burner modules are arranged on both sides of the swirl burner module. The modules are arranged close to the left wall and the right wall of the boiler body. The combustion effect of the DC burner is relatively high. Through this arrangement of burners, the DC burners are arranged on both sides of the swirl burner, and the DC burner modules are arranged close to the left wall and the right wall of the boiler body, that is, the DC burner modules are close to the side wall of the boiler body, which effectively improves the combustion efficiency of the coal powder close to the side wall. The improvement of the combustion efficiency means that the fuel can be burned more fully, reducing the unburned loss, which helps to reduce harmful substances in the combustion products, such as unburned carbon particles, carbon monoxide, etc., and at the same time, more fully Combustion can also reduce unburned carbon particles and other corrosive substances in the flue gas, such as sulfur oxides, nitrogen oxides, etc., and effectively reduce the risk of high-temperature corrosion of the heated surface; secondly, in the device, the DC burner module is connected to the wall-attached pulverizing system, and a coal powder concentration adjustment component is provided between the DC burner module and the wall-attached pulverizing system. The DC burner module is also provided with a wall-attached primary air adjustment component. When the DC burner module is running, the coal powder concentration on the side wall of the boiler body is adjusted by adjusting the coal powder concentration adjustment component and the wall-attached primary air adjustment component. When the DC burner module is shut down, the coal powder concentration on the side wall of the boiler body is adjusted by the wall-attached primary air adjustment component. During the adjustment process, the corrosion rate of the side wall is effectively controlled, thereby extending the service life of the equipment. The device can automatically adapt to different coal quality conditions and the reducing atmosphere in the near-wall area of ​​the furnace water-cooled wall. By adjusting the primary air volume of the shut-down wall-attached pulverizing system and adjusting the pulverized coal concentration entering the DC burners on both sides of the wall-attached pulverizing system, the CO concentration and H2S concentration in the near-wall area of ​​the water-cooled wall can be adjusted, reducing the risk of water-cooled wall tube thinning and water-cooled wall leakage shutdown caused by high-temperature corrosion, reducing water-cooled wall tube corrosion, reducing maintenance and tube replacement costs, and improving the operating safety of the hedge combustion boiler.

[0021] Furthermore, the swirl burner module includes a plurality of swirl burner assemblies arranged in parallel, any one of which is connected to a central pulverizing system, and a plurality of the central pulverizing systems constitute the central pulverizing system group. Firstly, the plurality of swirl burner assemblies arranged in parallel can ensure a more uniform flame distribution in the furnace, which helps to improve the stability and efficiency of combustion. Each group of swirl burner assemblies can independently obtain pulverized coal from the corresponding central pulverizing system, which makes the supply of pulverized coal more uniform, further enhancing the uniformity of combustion. Secondly, since each group of swirl burner assemblies is connected to a central pulverizing system, the pulverized coal can be supplied to the central pulverizing system more uniformly, thereby further enhancing the uniformity of combustion. Each burner component is connected to its own central pulverizing system, so the pulverized coal supply and air flow of each burner group can be adjusted individually according to actual operating requirements. This flexibility helps to cope with different coal quality conditions, load requirements and combustion conditions, and achieve more precise combustion control. In addition, the parallel central pulverizing systems constitute a pulverizing system group, so that when a single pulverizing system fails, other systems can continue to work to ensure the continuous operation of the boiler. This redundant design improves the reliability and stability of the entire boiler system and reduces downtime caused by pulverizing system failures.

[0022] Furthermore, the swirl burner assembly is composed of 2 to 4 groups, each group including 4 to 6 swirl burners. Firstly, the arrangement of multiple groups of swirl burner assemblies makes the flame distribution in the furnace more uniform, which helps the fuel to burn more fully, thereby improving the combustion efficiency. Each group contains multiple swirl burners, which can ensure the formation of stable flames in a larger furnace space and enhance the stability of combustion. Secondly, by adjusting the operating status of different groups or different swirl burners, the load of the boiler can be flexibly adjusted to adapt to different production needs. This flexibility helps to reduce energy consumption and improve the operating economy of the boiler. Moreover, the uniform distribution of multiple groups of swirl burner assemblies helps to make the heat load distribution of the heating surface of the furnace more uniform and reduce local overheating, which helps to extend the service life of the boiler and reduce maintenance costs.

[0023] Furthermore, the DC burner module includes a plurality of DC burners, and the DC burners are connected to the wall-attached powder making system. The number of DC burners in one DC burner module is not less than the number of groups of the swirl burner assembly, so that the combustion atmosphere of the DC burner can be fully isolated from the combustion atmosphere of the swirl burner, thereby protecting the boiler side wall.

[0024] Furthermore, the opposed-combustion boiler also includes a plurality of powder delivery pipes, and a plurality of the direct current burners are respectively connected to the wall-attached pulverizing system through the plurality of the powder delivery pipes; any one of the powder delivery pipes is provided with the coal powder concentration adjustment component. Firstly, the powder delivery pipe ensures that the coal powder is stably transported from the wall-attached pulverizing system to each direct current burner. This stable coal powder supply helps to maintain stable combustion of the flame in the boiler and improve combustion efficiency. The coal powder concentration in the powder delivery pipe can be accurately adjusted through the coal powder concentration adjustment component. By optimizing the coal powder concentration, the combustion conditions can be further improved and the degree of corrosion can be reduced.

[0025] Furthermore, the direct current burner includes a first nozzle and a second nozzle, and the first nozzle is arranged near the left wall or the right wall of the boiler body; when in use, the concentration of coal powder in the first nozzle is lower than the concentration of coal powder in the second nozzle. More precisely, by making the concentration of coal powder in the nozzle near the left wall or the right wall lower, the deposition of corrosive sludge near the side wall is effectively reduced, and the generation of corrosive gas near the side wall is also reduced, thereby reducing the corrosion rate of the side wall.

[0026] Furthermore, the wall-attached primary air regulating assembly includes a wall-attached hot primary air regulating valve and a wall-attached cold primary air regulating valve. The wall-attached hot primary air regulating valve and the wall-attached cold primary air regulating valve can accurately adjust the ratio of hot primary air and cold primary air entering the burner, thereby controlling the initial temperature and air volume of the pulverized coal airflow. This precise control helps to optimize combustion conditions, improve combustion efficiency and thermal efficiency. Precise control of air temperature and air volume helps to reduce heat loss from the boiler. By optimizing combustion conditions, the emission of unburned pulverized coal and smoke can be reduced, thereby reducing exhaust heat loss and improving thermal efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a structural schematic diagram of a high-temperature corrosion rate control device for the left and right water-cooled walls of an opposed combustion boiler in the present invention;

[0029] Figure 2 A schematic diagram of the arrangement of the front wall burner in one embodiment of the present invention;

[0030] Figure 3 A schematic diagram of the arrangement of a rear wall burner in one embodiment of the present invention;

[0031] Figure 4It is a schematic structural diagram of a device for controlling high temperature corrosion rate of the left and right water-cooled walls of an opposed combustion boiler according to an embodiment of the present invention;

[0032] Figure 5 It is a schematic diagram of the adjustment of the pulverized coal concentration adjustment device of the shutter blade structure type in the present invention;

[0033] Figure 6 It is the corresponding relationship between the blade angle of the pulverized coal concentration regulating device of the shutter blade structure type in the present invention and the CO peak value of the side wall water-cooled wall.

[0034] Among them: 1. Boiler body, 2. Swirl burner module, 21. Swirl burner assembly, 22. Swirl burner, 3. DC burner module, 31. DC burner, 311. First nozzle, 312. Second nozzle, 4. Middle powder making system group, 41. Middle powder making system, 5. Wall powder making system, 51. Wall powder making system, 6. Coal powder concentration adjustment component, 7. Wall primary air adjustment component, 71. Wall hot primary air adjustment valve, 72. Wall cold primary air adjustment valve, 8. Powder delivery pipeline, 9. Monitoring unit. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0038] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0039] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0040] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0042] Example 1

[0043] like Figure 1 As shown, the present invention discloses an opposed combustion boiler, comprising a boiler body 1, a control unit and a monitoring unit 9; the boiler body 1 consists of a front wall, a rear wall, a left wall and a right wall.

[0044] The burners are arranged on the front wall and the rear wall, and the corrosion occurs at the left wall and the right wall.

[0045] For the present invention, a swirl burner module 2 is provided on the front wall and the rear wall of the boiler body 1, and a DC burner module 3 is provided on both sides of the swirl burner module 2, and the DC burner module 3 is arranged close to the left wall and the right wall of the boiler body 1; the swirl burner module 2 is connected to the middle powder making system group 4, and the DC burner module 3 is connected to the wall powder making system 5, and a coal powder concentration adjustment component 6 is provided between the DC burner module 3 and the wall powder making system 5, and the DC burner module 3 is also provided with a wall primary air adjustment component 7; the coal powder concentration adjustment component 6 and the wall primary air adjustment component 7 are both in communication with the control unit, and the monitoring unit is arranged close to the left wall or the right wall of the boiler body 1, and communicates with the control unit.

[0046] like Figure 2 As shown, in a preferred embodiment, the swirl burner module 2 includes a plurality of groups of swirl burner assemblies 21 arranged in parallel, and any group of the swirl burner assemblies 21 is connected to a central powder making system 41, and a plurality of the central powder making systems 41 constitute the central powder making system group 4.

[0047] like Figure 3 As shown, in a preferred device, the swirl burner assemblies 21 are divided into 2 to 4 groups, and each group includes 4 to 6 swirl burners 22 .

[0048] The DC burner module 3 includes a plurality of DC burners 31, which are connected to the wall-attached powder making system 5. The number of DC burners 31 in a DC burner module 3 is not less than the number of groups of the swirl burner assembly 21, and an effective oxygen-rich layer can be formed on the side wall to protect the side wall, i.e., the left wall and the right wall.

[0049] The counter-firing boiler further comprises a plurality of powder delivery pipes 8 , and a plurality of the direct current burners 31 are respectively connected to the wall-attached powder making system 5 via the plurality of the powder delivery pipes 8 ; and the pulverized coal concentration regulating component 6 is provided on any one of the powder delivery pipes 8 .

[0050] The DC burner 31 includes a first nozzle 311 and a second nozzle 312. The first nozzle 311 is arranged near the side wall of the boiler body 1, that is, for the DC burner 31 near the right wall, its first nozzle 311 is arranged near the right wall, and for the DC burner 31 near the left wall, its first nozzle 311 is arranged near the left wall. When in use, the concentration of pulverized coal in the first nozzle 311 is lower than the concentration of pulverized coal in the second nozzle 312, that is, in a further optimized solution, the oxygen enrichment near the side wall is increased and the corrosion of the side wall is reduced.

[0051] Here, the concentration of the coal powder entering the first nozzle 311 and the second nozzle 312 is regulated by the coal powder concentration regulating component 6, and the regulation method can be carried out in the form of a shutter.

[0052] In a preferred solution, the wall-attached primary air regulating component 7 includes a wall-attached hot primary air regulating valve 71 and a wall-attached cold primary air regulating valve 72 .

[0053] That is, the present invention discloses a counter-combustion boiler, including a burner, a pulverizing system, a pulverized coal concentration regulating device and a control system, and a data monitoring system that communicates with the control system, namely, a monitoring system; the burner includes direct current burners on both sides and a central swirl burner; the pulverizing system includes a central pulverizing system connected to the central swirl burner and a wall-attached pulverizing system connected to the direct current burners on both sides; the pulverized coal concentration regulating device is arranged at the inlet of the direct current burners on both sides; the wall-attached pulverizing system includes a coal feeder, a coal mill, a hot air regulating valve, and a cold air regulating valve; the data monitoring system includes a sulfur content monitoring device for the coal entering the furnace and a flue gas composition measuring device for the side wall water-cooled wall, and the side wall water-cooled wall flue gas composition measuring device includes a flue gas measuring hole and a flue gas analyzer for monitoring the sulfur content of the coal entering the furnace and the CO and H2S concentration distribution near the water-cooled wall. The device can automatically adapt to different coal quality conditions and the reducing atmosphere in the water-cooled wall near-wall area of ​​the furnace. By adjusting the air volume of the burners on both sides and the coal powder concentration ratio of the burners on both sides, the CO concentration and H2S concentration in the water-cooled wall near-wall area are regulated, thereby reducing the risk of water-cooled wall tube thinning and water-cooled wall leakage shutdown caused by H2S high-temperature corrosion, reducing maintenance and tube replacement costs, and improving the operating safety of the hedge combustion boiler.

[0054] In the present invention, the DC burners on both sides are the burners closest to the left wall or the right wall in each layer of burners, and the central swirl burner is the other burners except the DC burners on both sides. The DC burners on both sides and the central burner belong to different powder making systems. The output of the wall-attached powder making system is less than or equal to the middle powder making system, and the air volume of the wall-attached powder making system is greater than or equal to the middle powder making system under the same coal amount. When the coal mill of the wall-attached powder making system is shut down, the wall-attached hot primary air regulating valve and the wall-attached cold primary air regulating valve can be set to a certain opening, and the primary air volume entering the burners on both sides can be independently adjusted without affecting the primary air volume entering other burners. In the present invention, the DC burners on both sides and their associated powder making systems are relatively independent and can be adjusted independently.

[0055] When the wall-attached pulverizing system is put into operation, the pulverized coal concentration of the DC burners on both sides can be adjusted according to the data measured by the data monitoring system. When the wall-attached pulverizing system is shut down, the primary air volume of the DC burners on both sides can be adjusted according to the data measured by the data monitoring system. The sulfur content of the coal entering the furnace can be determined by offline measurement or by online measurement of the ratio of flue gas SO2 to boiler load.

[0056] When the pulverizing system arranged in the middle of the boiler is put into operation and the pulverizing system attached to the wall is shut down under medium and low load, the control system obtains the detection data of the sulfur content of the coal entering the furnace, the air-coal ratio of the pulverizer, and the distribution of CO and H2S concentrations near the water-cooled wall, and adjusts the hot air regulating valve and cold air regulating valve of the pulverizing system attached to the wall to adjust the primary air volume entering the DC burners on both sides through the acquired monitoring data to reduce the CO and H2S concentrations near the water-cooled wall. That is, the pulverizing system attached to the wall is used as a backup under medium and low load rates. When the pulverizing system attached to the wall is shut down, the burners on both sides can be used as wall wind nozzles to send in primary and secondary air without pulverized coal, which plays a role in increasing the oxygen concentration of the side wall, reducing the CO and H2S concentration of the side wall, and reducing the high-temperature corrosion rate. When selecting, the pulverizing system attached to the wall can be selected as a pulverizer with small output and large air-coal ratio. The pulverized coal concentration sent to the pulverized coal airflow by the burners on both sides is low, which is conducive to the control of the reducing atmosphere of the side wall and reduces the high-temperature corrosion rate.

[0057] When the centrally arranged pulverizing system and part or all of the wall-attached pulverizing systems are put into operation under medium and high boiler loads, the control system obtains the detection data of the sulfur content of the coal entering the furnace, the air-coal ratio of the pulverizer, and the distribution of CO and H2S concentrations near the water-cooled wall, and adjusts the pulverized coal concentration regulating device of the wall-attached pulverizing system according to the acquired monitoring data to increase the primary air oxygen concentration of the direct current burners on both sides, so as to reduce the CO and H2S concentrations near the water-cooled wall.

[0058] Example 2

[0059] like Figure 1 As shown, the present invention discloses a counter-combustion boiler, including a control system, and several regulating systems and a data monitoring system that communicate with the control system; the data monitoring system is used to monitor the sulfur content of coal entering the furnace and the flue gas composition of the side wall water-cooled wall; several of the regulating systems include a hot primary air regulating door, a cold primary air regulating door, and a coal powder concentration regulating device, which are used to adjust the primary air volume when the wall-attached pulverizing system is shut down, and the coal powder concentration of the light side nozzles of the DC burners on both sides close to the side walls when the wall-attached pulverizing system is put into operation.

[0060] In a preferred embodiment,

[0061] The control device is arranged in the boiler of the 1000MW unit, using the counter combustion method, with 3 layers of burners on the front and rear walls, 8 burners on each wall and each layer, the burners close to the side walls are direct current burners, and the other burners are swirl burners. There are 8 coal mills in total, 6 burners on the front wall close to the side walls are connected to one coal mill, 6 burners on the rear wall close to the side walls are connected to one coal mill, and the remaining 6 burners in the middle of each layer are connected to one coal mill.

[0062] like Figure 2The figure shows the layout of the water-cooled wall burners on the front wall of the boiler. The middle pulverizing system A mill is connected to the middle swirl burner on the lower layer, the middle pulverizing system B mill is connected to the middle swirl burner on the middle layer, and the middle pulverizing system C mill is connected to the middle swirl burner on the upper layer. The six powder delivery pipes at the outlet of the SF mill of the wall-attached pulverizing system are connected to the DC burners on both sides of the front wall. A pulverized coal concentration adjustment device is arranged on each branch powder delivery pipe, which can change the pulverized coal concentration of the thick and thin nozzles of the DC burners on both sides of the front wall after adjustment.

[0063] When the unit load is below 85%, the wall-attached pulverizing system is in a shutdown state, and the opening of the hot primary air regulating door and the cold primary air regulating door are adjusted according to the data measured by the data monitoring system. The high-temperature corrosion rate is controlled by adjusting the air volume of the shutdown wall-attached pulverizing system.

[0064] When the unit load is above 85%, one coal mill in the wall-attached pulverizing system is in shutdown state, and the opening of the hot primary air regulating door and the cold primary air regulating door are adjusted according to the data measured by the data monitoring system; one coal mill is in operation, and the hot primary air door is adjusted according to the coal mill air-coal ratio curve, and the opening of the cold primary air regulating door is adjusted according to the preset mill outlet temperature, and the corresponding coal powder concentration regulating device is adjusted according to the data measured by the data monitoring system. The high-temperature corrosion rate is controlled by the air volume adjustment of the shutdown wall-attached pulverizing system and the coal powder concentration regulating device of the operation wall-attached pulverizing system.

[0065] When the central pulverizing system fails and stops operating or the actual coal quality is low, causing all the wall-attached pulverizing systems to be put into operation, the hot primary air door of the wall-attached pulverizing system is adjusted according to the air-coal ratio curve of the coal mill, the opening of the cold primary air regulating door is adjusted according to the preset mill outlet temperature, and the corresponding coal powder concentration regulating device is adjusted according to the data measured by the data monitoring system. The high-temperature corrosion rate is controlled by the corresponding coal powder concentration regulating device of the wall-attached pulverizing system in operation.

[0066] Example 3

[0067] The control device is arranged in the boiler of the 300MW unit boiler, which adopts the hedge combustion method, with 2 layers of burners on the front and rear walls, 6 burners on each wall and each layer, the burners close to the side walls are direct current burners, and the other burners are swirl burners. There are 6 coal mills in total, 4 burners on the front wall close to the side walls are connected to one coal mill, 4 burners on the rear wall close to the side walls are connected to one coal mill, and the remaining 4 burners in the middle of each layer are connected to one coal mill. Figure 3The diagram shows the rear wall layout. The middle pulverizing system F mill is connected to the lower middle swirl burner, and the middle pulverizing system F mill is connected to the upper middle swirl burner. The four powder delivery pipes at the outlet of the wall-attached pulverizing system SR mill are connected to the DC burners on both sides of the rear wall. Each branch powder delivery pipe is equipped with a pulverized coal concentration adjustment device, which can change the pulverized coal concentration of the thick and thin nozzles of the DC burners on both sides of the rear wall after adjustment.

[0068] When the unit load is below 80%, the wall-attached pulverizing system is in a shutdown state, and the opening of the hot primary air regulating door and the cold primary air regulating door are adjusted according to the data measured by the data monitoring system. The high-temperature corrosion rate is controlled by adjusting the air volume of the shutdown wall-attached pulverizing system.

[0069] When the unit load is above 80%, one coal mill in the wall-attached pulverizing system is in shutdown state, and the opening of the hot primary air regulating door and the cold primary air regulating door are adjusted according to the data measured by the data monitoring system; one coal mill is in operation, and the hot primary air door is adjusted according to the coal mill air-coal ratio curve, and the opening of the cold primary air regulating door is adjusted according to the preset mill outlet temperature, and the corresponding coal powder concentration regulating device is adjusted according to the data measured by the data monitoring system. The high-temperature corrosion rate is controlled by the air volume adjustment of the shutdown wall-attached pulverizing system and the coal powder concentration regulating device of the operation wall-attached pulverizing system.

[0070] When the central pulverizing system fails and stops operating or the actual coal quality is low, causing all the wall-attached pulverizing systems to be put into operation, the hot primary air door of the wall-attached pulverizing system is adjusted according to the air-coal ratio curve of the coal mill, the opening of the cold primary air regulating door is adjusted according to the preset mill outlet temperature, and the corresponding coal powder concentration regulating device is adjusted according to the data measured by the data monitoring system. The high-temperature corrosion rate is controlled by the corresponding coal powder concentration regulating device of the wall-attached pulverizing system in operation.

[0071] Example 4

[0072] Based on the idea of ​​the present invention, a pulverized coal concentration regulating component 6 can be set on the burner close to the wall instead of the DC burner module. Preferably, a pulverized coal concentration regulating component is set on the two burners close to the side wall. Figure 4 For example, the control device is arranged in the boiler of a 1000MW unit boiler, which adopts the counter combustion mode, with 3 layers of burners on the front and rear walls, and 8 swirl burners on each wall and each layer. There are 4 pulverized coal pipelines at the outlet of each coal mill, which are connected to the 8 swirl burners on each wall and each layer after passing through the pulverized coal concentration regulating device. By adjusting the pulverized coal concentration regulating device, the pulverized coal concentration of the first swirl burner closest to the side wall and the second burner close to the side wall can be changed, thereby reducing the CO concentration of the side wall water-cooled wall.

[0073] In addition, if Figure 5As shown, the pulverized coal concentration regulating device can adopt louver blades, in which the left figure shows that the angle between the blades and the flow direction of the pulverized coal is 45°. At this angle, the CO concentration of the side wall water-cooled wall decreases, that is, the larger the angle, the greater the concentration-lean ratio on both sides of the outlet. The light side is connected to the burner close to the side wall, and the CO concentration of the side wall is effectively controlled. In the right figure, the angle between the blades and the flow direction is 15°. At this angle, the CO concentration of the side wall water-cooled wall increases.

[0074] Figure 6 The calculation results of the blade rotation angle and the reduction ratio of the side wall CO concentration peak value obtained by numerical simulation of this embodiment (compared with the working condition where the coal powder concentration regulating device is not arranged and the coal powder concentration of the first swirl burner closest to the side wall and the second burner close to the side wall are equal) are shown in the figure. It can be seen from the figure that the CO concentration of the side wall water-cooled wall can be effectively adjusted by adjusting the angle between the blades and the coal powder flow direction in the coal powder concentration regulating device with a louver blade structure.

[0075] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A counter-firing boiler, characterized in that: The boiler comprises a boiler body (1), a control unit and a monitoring unit (9); a swirl burner module (2) is provided on the front wall and the rear wall of the boiler body (1); a direct current burner module (3) is provided on both sides of the swirl burner module (2); and the direct current burner module (3) is arranged close to the left wall and the right wall of the boiler body (1); The swirl burner module (2) is connected to a middle pulverizing system group (4), the DC burner module (3) is connected to a wall-attached pulverizing system (5), a pulverized coal concentration adjustment component (6) is provided between the DC burner module (3) and the wall-attached pulverizing system (5), and the DC burner module (3) is also provided with a wall-attached primary air adjustment component (7); The pulverized coal concentration adjustment component (6) and the wall-attached primary air adjustment component (7) both communicate with the control unit, and the monitoring unit is arranged close to the left wall or the right wall of the boiler body (1) and communicates with the control unit.

2. The opposed-firing boiler according to claim 1, characterized in that: The swirl burner module (2) comprises a plurality of groups of swirl burner assemblies (21) arranged in parallel, any group of the swirl burner assemblies (21) is connected to a middle powder making system (41), and a plurality of the middle powder making systems (41) constitute the middle powder making system group (4).

3. The opposed-firing boiler according to claim 2, characterized in that: The swirl burner assemblies (21) are divided into 2 to 4 groups, and each group includes 4 to 6 swirl burners (22).

4. The opposed-firing boiler according to claim 2, characterized in that: The DC burner module (3) comprises a plurality of DC burners (31), and the DC burners (31) are connected to the wall-adherent powder making system (5).

5. The opposed-firing boiler according to claim 4, characterized in that: The number of direct-flow burners (31) in a direct-flow burner module (3) is not less than the number of groups of the swirl burner assemblies (21).

6. The opposed-firing boiler according to claim 4, characterized in that: The counter-firing boiler further comprises a plurality of powder delivery pipes (8), and a plurality of the direct current burners (31) are respectively connected to the wall-attached powder making system (5) via the plurality of the powder delivery pipes (8); and the pulverized coal concentration regulating component (6) is provided on any one of the powder delivery pipes (8).

7. The opposed-firing boiler according to claim 6, characterized in that: The direct current burner (31) comprises a first nozzle (311) and a second nozzle (312), wherein the first nozzle (311) is arranged close to a side wall of the boiler body (1); when in use, the concentration of coal powder in the first nozzle (311) is lower than the concentration of coal powder in the second nozzle (312).

8. The opposed-firing boiler according to claim 6, characterized in that: The wall-attached primary air regulating component (7) comprises a wall-attached hot primary air regulating valve (71) and a wall-attached cold primary air regulating valve (72).

9. A method for using a counter-firing boiler as claimed in claims 1 to 8, characterized in that: Using the monitoring unit to obtain the smoke components of the left wall and the right wall close to the boiler body (1), and feeding the data back to the control unit; When the wall-attached pulverizing system (5) is in operation, the control unit adjusts the pulverized coal concentration adjustment component (6) and the wall-attached primary air adjustment component (7) so that the smoke composition on the side wall of the boiler body (1) meets the operating condition requirements. When the wall-attached pulverizing system (5) is stopped, the wall-attached primary air adjustment component (7) is used to adjust the smoke composition on the side wall of the boiler body (1) to meet the operating condition requirements.

10. The method for using a counter-firing boiler according to claim 9, characterized in that: When the unit load is below 80%, the wall-attached powder making system (5) is shut down, and the DC burner module (3) only delivers hot primary air as wall-attached air.

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