Ultralow-load stable-combustion burner for pulverized coal fired boiler

Abstract

The invention discloses an ultralow-load stable-combustion burner for a pulverized coal fired boiler, relates to a burner of a boiler, and aims to solve the problems of unstable combustion and even flameout of a traditional burner when the boiler runs in a load-reducing manner. The high-concentration pulverized coal burner comprises a pulverized coal pipeline, a pulverized coal homogenizing device, a burner body, a partition baffle and a high-concentration pulverized coal concentrator, the partition baffle is installed inside the burner body and connected with the burner nozzle, the partition baffle divides the burner nozzle into an upper part, a middle part and a lower part, the high-concentration pulverized coal concentrator is installed inside the burner body close to the partition baffle, and an outlet of the pulverized coal pipeline is connected with the inlet end of the burner body. And the powder homogenizing device is mounted in the pulverized coal pipeline close to the inlet of the burner body. The method is applied to the field of pulverized coal boilers.

Description

Technical Field

[0001] The invention relates to a burner of a boiler, in particular to an ultra-low load stable combustion burner for a pulverized coal boiler. The invention is applied to the field of pulverized coal boilers. Background Art

[0002] In order to achieve the dual carbon goals and gradually build a new power system with new energy as the main body, coal-fired power generation will transform from the main power source of power production to basic guarantee and system regulation power source. As for the current development trend, deep and rapid peak regulation is the main development direction of thermal power generation. In the process of deep peak regulation, the insufficient low-load stable combustion capacity of the boiler is one of the main problems limiting deep peak regulation. In order to reduce the operating load of the boiler, the traditional method will lead to a significant increase in power generation energy consumption. At the same time, it is difficult to control low-load and transient process pollutant emissions. When the traditional burner is running at reduced load, the combustion will be unstable or even flameout. Therefore, it is a prerequisite to ensure the safety of low-load operation of the boiler and to ensure the stable combustion of the burner. At present, the burner has insufficient low-load stable combustion capacity for high-quality coal, and it is even more impossible to achieve stable combustion at low load for difficult-to-burn coal. This is a common problem faced by pulverized coal power station boilers. Therefore, it is necessary to develop a burner that can burn stably under ultra-low load operation conditions. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the conventional burner may have unstable combustion or even flameout when the boiler is running at reduced load, and further provide an ultra-low load stable combustion burner for a pulverized coal boiler.

[0004] The technical solution adopted by the present invention to solve the above problems is:

[0005] An ultra-low load stable combustion burner for a pulverized coal boiler, comprising a pulverized coal pipeline, a pulverized coal uniformity device, a burner body, a partition baffle and a high-concentration pulverized coal concentrator;

[0006] A partition baffle is installed inside the burner body, and the partition baffle is connected to the burner nozzle. The partition baffle divides the burner nozzle into three parts: upper, middle and lower parts. A high-concentration pulverized coal concentrator is installed inside the burner body close to the partition baffle. The pulverized coal pipeline outlet is connected to the inlet end of the burner body, and a powder equalizing device is installed in the pulverized coal pipeline close to the inlet of the burner body.

[0007] Furthermore, it also includes a connecting flange; the outlet of the pulverized coal pipeline is connected to the inlet of the burner body through the flange.

[0008] Furthermore, the burner body is a square cylinder, and a combustion stabilizing blunt body is provided at the burner nozzle.

[0009] Furthermore, the partition baffle includes an upper baffle and a lower baffle, which are installed side by side and in parallel in the burner body, the two side surfaces of the upper baffle are fixedly installed on the inner wall of the burner body, and the two side surfaces of the lower baffle are fixedly installed on the inner wall of the burner body, and the end of the partition baffle close to the burner outlet is connected to the burner nozzle stabilizing body.

[0010] Furthermore, the high-concentration pulverized coal concentrator is composed of a plurality of baffles, both ends of each baffle are fixedly mounted on the inner wall of the burner body, and the angle between the strip plate of the high-concentration pulverized coal concentrator and the axis of the burner body is a.

[0011] Furthermore, the distance between two adjacent strip plates in the burner body in the horizontal direction is L, and the distance between two adjacent strip plates in the vertical direction is H.

[0012] Furthermore, the length of the upper partition is smaller than the length of the lower partition, and the length difference between the upper partition and the lower partition is d.

[0013] Beneficial effects of the present invention:

[0014] 1. The burner of the present application has high adaptability to coal types and has good stable combustion effect for lignite, bituminous coal, lean coal and anthracite.

[0015] 2. The burner of the present application can achieve ultra-low load stable combustion below 15% load for different types of coal in power station boilers.

[0016] 3. The burner of the present application has a short ignition distance, ensuring stable combustion of the ultra-low load burner.

[0017] 4. The high-temperature flue gas refluxes at the burner nozzle of the present application, further ensuring the ignition of coal powder under ultra-low load operating conditions.

[0018] 5. The burner of the present application eliminates the influence of the pulverized coal pipeline elbow on the pulverized coal concentration effect.

[0019] The present invention adopts a coal powder concentration device to deeply concentrate the coal powder. Under ultra-low load operating conditions, to ensure the full combustion of the coal powder, the coal powder fineness needs to be reduced. At this time, the traditional coal powder burner has a poor effect on coal powder concentration, which limits the lower limit of the boiler load. The ultra-low load stable combustion burner of the present application utilizes an upper and lower baffle structure to form a high-concentration coal powder concentrator to deeply concentrate the coal powder. Due to inertia, the coal powder is fully concentrated to the middle of the burner. When the boiler load is reduced to below 15%, due to the decrease in coal powder fineness, the quality of coal powder particles is reduced, and the amount of coal powder carried away by the higher wind speed area of ​​the baffle gap is reduced. The coal powder concentration ratio in the middle of the burner is increased, and the coal powder concentration is increased, which provides a strong guarantee for the stable combustion of the burner with a load below 15%.

[0020] In actual operation, a powder distribution device is provided at the burner inlet of the present invention, and the number of the powder distribution devices is 1 or 2, which are designed and manufactured according to the coal powder concentration requirements of the actual project. The high-concentration coal powder concentrator formed by multiple baffles works together to ensure the high coal powder airflow concentration in the middle of the burner. The blunt body on the burner nozzle 7 causes the high-temperature flue gas to partially reflux, reducing the adverse effect of the furnace temperature level drop on the ultra-low load stable combustion under ultra-low load operation conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of this application. DETAILED DESCRIPTION

[0022] Specific implementation method 1: Combination Figure 1 The present embodiment is described as follows: the ultra-low load stable combustion burner for a pulverized coal boiler comprises a pulverized coal pipeline 1, a pulverized coal uniformity device 2, a burner body 5, a partition baffle 6 and a high-concentration pulverized coal concentrator 4;

[0023] The partition baffle 6 is installed inside the burner body 5, and the partition baffle 6 is connected to the combustion stabilizing body of the burner nozzle 7 at one end near the burner outlet. The high-concentration pulverized coal concentrator 4 composed of multi-stage baffles is installed inside the burner body 5 near the partition baffle 6. The outlet of the pulverized coal pipeline 1 is connected to the inlet of the burner body 5. The powder uniformizing device 2 is installed in the pulverized coal pipeline 1 near the inlet of the burner body 5.

[0024] Specific implementation method 2: Combination Figure 1 This embodiment describes an ultra-low load stable combustion burner for a pulverized coal boiler, which further includes a connecting flange 3; the outlet of the pulverized coal pipeline 1 and the inlet of the burner body 5 are connected via the flange 3. Other methods are the same as those of the first embodiment.

[0025] Specific implementation method three: Combination Figure 1 This embodiment is described as an ultra-low load stable combustion burner for a pulverized coal boiler, wherein the burner body 5 is a square cylinder, and the partition baffle 6 is connected to the stable combustion blunt body of the burner nozzle 7. Other methods are the same as those of the first embodiment.

[0026] Specific implementation method four: Combination Figure 1 This embodiment is described. This embodiment is an ultra-low load stable combustion burner for a pulverized coal boiler. The partition baffle 6 includes an upper baffle and a lower baffle. The upper baffle and the lower baffle are installed side by side and in parallel in the burner body 5. The two sides of the upper baffle are fixedly installed on the inner side wall of the burner body 5. The two sides of the lower baffle are fixedly installed on the inner side wall of the burner body 5. The partition baffle 6 is connected to the stable combustion blunt body of the burner nozzle 7 at one end close to the burner outlet. Other methods are the same as those in the third embodiment.

[0027] Specific implementation method five: Combination Figure 1 This embodiment is described. In this embodiment, a super-low load stable combustion burner for a pulverized coal boiler is described. The high-concentration pulverized coal concentrator 4 is composed of a plurality of strip baffles. Both ends of each baffle are fixedly mounted on the inner wall of the burner body 5. The strip plate of the high-concentration pulverized coal concentrator and the axis of the burner body 5 are at an angle of a. Other methods are the same as those in the first embodiment.

[0028] Specific implementation method six: Combination Figure 1 This embodiment describes an ultra-low load stable combustion burner for a pulverized coal boiler, wherein the horizontal distance between two adjacent strip plates in the burner body 5 is L, and the vertical distance between two adjacent strip plates is H. Other methods are the same as those in the fifth embodiment.

[0029] Specific implementation method seven: Combination Figure 1 This embodiment describes an ultra-low load stable combustion burner for a pulverized coal boiler, wherein the length of the upper baffle is less than the length of the lower baffle, and the length difference between the upper and lower baffles is d. Other methods are the same as those in the fifth embodiment.

[0030] The high-concentration pulverized coal concentrator formed by multiple baffles in the present invention can adjust the horizontal spacing L and the vertical spacing H between two adjacent flow dividers according to different types of coal to meet the requirements of different coal qualities for the optimal combustion pulverized coal concentration. The lower baffle exceeds the length d of the upper baffle, and is adjusted according to the different coal qualities of different engineering projects, so as to achieve the adaptability of the burner to multiple types of coal and ensure that different types of coal can achieve ultra-low load operation below 15%. The combined effect of the concentrator inside the entire burner makes the primary air velocity of the high-concentration pulverized coal airflow in the middle of the burner nozzle slightly lower than the primary air concentration of the upper and lower light phases, shortening the ignition distance of the burner pulverized coal airflow, and further ensuring the ignition of the burner pulverized coal airflow under ultra-low load operation conditions.

[0031] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. An ultra-low load stable combustion burner for a pulverized coal boiler, characterized in that: It comprises a coal powder pipeline (1), a powder distribution device (2), a burner body (5), a partition baffle (6) and a high-concentration coal powder concentrator (4); A partition baffle (6) is installed inside the burner body (5), the partition baffle (6) is connected to the burner nozzle (7), and the nozzle is divided into three parts: upper, middle and lower. A high-concentration pulverized coal concentrator (4) is installed inside the burner body (5) near the partition baffle (6). The outlet end of the pulverized coal pipeline (1) is connected to the inlet end of the burner body (5). A powder distribution device (2) is installed inside the pulverized coal pipeline (1) near the inlet of the pulverized coal burner.

2. The ultra-low load stable combustion burner for a pulverized coal boiler according to claim 1, characterized in that: It also includes a flange (3); the pulverized coal pipeline (1) is connected to the inlet of the pulverized coal burner (5) through the flange (3).

3. The ultra-low load stable combustion burner for a pulverized coal boiler according to claim 1, characterized in that: The burner body (5) is a square cylinder, and a combustion stabilizing blunt body is arranged at the burner nozzle (7).

4. The ultra-low load stable combustion burner for a pulverized coal boiler according to claim 3, characterized in that: The partition baffle (6) comprises an upper partition and a lower partition, the upper partition and the lower partition are installed side by side and in parallel in the burner body (5), the two side surfaces of the upper partition are fixedly installed on the inner side wall of the burner body (5), and the two side surfaces of the lower partition are fixedly installed on the inner side wall of the burner body (5), and the partition baffle (6) is connected to the burner nozzle combustion stabilizing blunt body at one end close to the burner outlet.

5. The ultra-low load stable combustion burner for a pulverized coal boiler according to claim 1, characterized in that: The high-concentration pulverized coal concentrator (4) is composed of a plurality of baffles arranged in a staggered manner. The plurality of baffles are installed in a burner body (5). Both ends of each baffle are fixedly installed on the inner wall of the burner body (5). The angle between the baffle of the high-concentration pulverized coal concentrator and the axis of the burner body (5) is a.

6. The ultra-low load stable combustion burner for a pulverized coal boiler according to claim 5, characterized in that: The distance between two adjacent strip plates in the burner body (5) in the horizontal direction is L, and the distance between two adjacent strip plates in the vertical direction is H.

7. The ultra-low load stable combustion burner for a pulverized coal boiler according to claim 5, characterized in that: The length of the upper partition is smaller than that of the lower partition, and the length difference between the upper partition and the lower partition is d.

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