A swirl combustion device and a swirl combustion method for adjusting the length-diameter ratio of a pre-chamber

Abstract

A swirl combustion device and a swirl combustion method for adjusting the aspect ratio of a pre-combustion chamber. The present invention relates to a combustion device for an industrial pulverized coal boiler. In order to completely solve the slagging problem of a boiler using a pre-combustion chamber burner when the coal quality changes, a primary air duct, an inner secondary air duct, and an outer secondary air duct are arranged in sequence from the inside out. The outlets of the primary air duct, the inner secondary air duct, and the outer secondary air duct are all communicated with the combustion chamber of the adjustable pre-combustion chamber. The driving part of the adjustable pre-combustion chamber is installed outside the outer secondary air duct. The separated secondary air duct is sleeved outside the outer secondary air duct and the combustion chamber of the adjustable pre-combustion chamber. The length of the combustion chamber of the adjustable pre-combustion chamber is adjusted in the axial direction of the outer secondary air duct. A video flame detector, an outlet temperature sensor, and a cylinder wall temperature sensor are installed on the combustion chamber of the adjustable pre-combustion chamber. The present invention is used in the field of boilers.

Description

Technical Field

[0001] The present invention relates to a combustion device for an industrial pulverized coal boiler, and more particularly to a swirl combustion device with an adjustable length-diameter ratio of a pre-combustion chamber and a swirl combustion method. The present invention is used in the field of boilers. Background Art

[0002] Boilers equipped with pre-combustion chamber burners have the advantages of stable combustion, convenient start-stop, low pollutant emission concentration, and wide load regulation range, and are widely used in the fields of power supply and heating. Coals in China can be divided into anthracite, bituminous coal, lean coal, and lignite according to different volatile contents. There are obvious differences in the ignition and combustion characteristics of different coal types. In the actual operation of coal-fired boilers, the situation of mixing coals or different coal types is often encountered. When the coal quality changes during combustion, if the boiler lacks a matching combustion system, problems such as difficult burnout of pulverized coal and slagging in the furnace will occur. Slagging in the pre-combustion chamber and near the outlet may cause the temperature in the furnace to rise; the negative pressure in the furnace decreases and gradually becomes positive; slagging on the wall of the pre-combustion chamber may affect the air flow field in the pre-combustion chamber and affect the stable combustion of the boiler; the falling of large slag blocks may damage the cold ash hopper at the bottom of the furnace or the water-cooled wall pipes of the furnace, causing serious safety accidents. Therefore, preventing slagging is of great significance for improving the safety and economy of boiler operation.

[0003] In order to completely solve the slagging problem of boilers with pre-combustion chamber burners when the coal quality changes, the present invention proposes a swirl combustion device and a swirl combustion method. Summary of the Invention

[0004] The present invention aims to completely solve the slagging problem of boilers with pre-combustion chamber burners when the coal quality changes, and further proposes a swirl combustion device and a swirl combustion method.

[0005] The technical solution adopted by the present invention to solve the above problems is:

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] A swirl combustion device with an adjustable length-diameter ratio of a pre-combustion chamber, which includes a primary air duct, an inner secondary air duct, an outer secondary air duct, and a separated secondary air duct; it also includes a video flame detector, an outlet temperature sensor, a barrel wall temperature sensor, and an adjustable pre-combustion chamber;

[0008] The primary air duct, the inner secondary air duct, and the outer secondary air duct are arranged in sequence from the inside out. The outlets of the primary air duct, the inner secondary air duct, and the outer secondary air duct are all connected to the combustion chamber of the adjustable pre-combustion chamber. The driving part of the adjustable pre-combustion chamber is installed outside the outer secondary air duct. The separated secondary air duct is sleeved outside the outer secondary air duct and the combustion chamber of the adjustable pre-combustion chamber. The length of the combustion chamber of the adjustable pre-combustion chamber is adjusted along the axial direction of the outer secondary air duct. The video flame detector, the outlet temperature sensor, and the cylinder wall temperature sensor are installed on the combustion chamber of the adjustable pre-combustion chamber.

[0009] Further, the combustion chamber of the adjustable pre-combustion chamber includes a pre-combustion inner sleeve and a pre-combustion outer sleeve;

[0010] The outlet end of the pre-combustion outer sleeve is installed at the inlet of the furnace and is connected to the furnace. The pre-combustion inner sleeve is slidably arranged inside the pre-combustion outer sleeve. The outlets of the primary air duct, the inner secondary air duct, and the outer secondary air duct are all connected to the pre-combustion inner sleeve.

[0011] Further, a plurality of slide rails are arranged along the length direction on the inner wall of the pre-combustion outer sleeve, and limiters are installed at both ends of each slide rail. At least two rows of rollers are arranged on the outer wall of the outlet of the pre-combustion inner sleeve. The pre-combustion inner sleeve is slidably arranged on the slide rails of the pre-combustion outer sleeve through the rollers.

[0012] Further, the driving part of the adjustable pre-combustion chamber includes a bracket, two tie rods, two connecting mechanisms, four limit nuts, and four gaskets;

[0013] The two tie rods are arranged oppositely on the bracket. The tie rods are processed with threaded sections. The threaded section of each tie rod is arranged on the bracket, and two limit nuts are threadedly connected to the threaded section of each tie rod. The two limit nuts are located on both sides of the bracket. A gasket is arranged between each limit nut and the bracket. One end of each tie rod is connected to the pre-combustion inner sleeve through a connecting mechanism.

[0014] Further, the video flame detector is installed on the pre-combustion inner sleeve near the outlet of the outer secondary air duct. An outlet temperature sensor is installed on the pre-combustion inner sleeve near the connecting mechanism. A cylinder wall temperature sensor is installed on the pre-combustion outer sleeve near the furnace wall of the furnace.

[0015] A swirl combustion method for a swirl combustion device with an adjustable pre-combustion chamber aspect ratio, the method is realized according to the following steps:

[0016] Step 1: According to the softening temperature ST of the coal used, the temperature T1 of the outlet temperature sensor, and the temperature T2 of the cylinder wall temperature sensor, combine with slagging to adjust the recirculation zone in the adjustable pre-combustion chamber, and adjust the ratios of the distance m1 between the burner outlet and the starting point of the recirculation zone, the recirculation zone length m, and the recirculation zone diameter d to the pre-combustion chamber diameter respectively;

[0017] Step 2: Observe the slagging condition at the outlet of the adjustable pre - combustion chamber through the DSC of the boiler, and control the adjustable aspect ratio of the adjustable pre - combustion chamber 20 to clean the slag blocks of the slagging.

[0018] Furthermore, in Method 1 of Step 1: When the softening temperature ST of the coal being burned > 1390 °C, or 800 °C ≥ the temperature T1 of the outlet temperature sensor > 150 °C, or 200 ≥ the temperature T2 of the cylinder wall temperature sensor > 150 °C, and the thickness of the slagging layer is within 0 - 30 mm, a large - scale recirculation zone needs to exist in the pre - combustion chamber. Therefore, pull the rod to adjust the position of the inner sleeve in the pre - combustion chamber, so that L = 1.2 - 1.4, where L is the length of the pre - combustion chamber, and make m1 = 0.05 - 0.1D, m = 1.0 - 1.15D, d = 0.8 - 0.85D in the central recirculation zone of the pre - combustion chamber.

[0019] Furthermore, in Method 2 of Step 1: When the softening temperature ST of the coal being burned is between 1260 - 1390 °C, or 850 ≥ the temperature T1 of the outlet temperature sensor > 800 °C, or the temperature T2 of the cylinder wall temperature sensor > 200 °C, and the thickness of the slagging layer is within 30 - 100 mm, a large - scale recirculation zone needs to exist in the pre - combustion chamber. Therefore, pull the rod to adjust the position of the inner sleeve in the pre - combustion chamber, so that L = 1.0 - 1.2D, where L is the length of the pre - combustion chamber, and make m1 = 0.1 - 0.15D, m = 0.7 - 1.0D, d = 0.6 - 0.8D in the central recirculation zone of the pre - combustion chamber.

[0020] Furthermore, in Method 3 of Step 1: When the softening temperature ST of the coal being burned ≤ 1260, or the temperature T1 of the outlet temperature sensor > 850 °C, and the thickness of the slagging layer > 100 mm, a small - scale recirculation zone needs to exist in the pre - combustion chamber. Therefore, pull the rod to adjust the position of the inner sleeve in the pre - combustion chamber, so that L = 0.8 - 1.0D, where L is the length of the pre - combustion chamber, and make m1 = 0.15 - 0.25D, m = 0.6 - 0.7D, d = 0.5 - 0.6D in the central recirculation zone of the pre - combustion chamber.

[0021] Furthermore, in Step 2, control the adjustable aspect ratio of the adjustable pre - combustion chamber to clean the slag blocks of the slagging. Pull the rod to make the inner sleeve in the pre - combustion chamber telescopic in the outer sleeve of the pre - combustion chamber and shake off the slag blocks.

[0022] The beneficial effects of the present invention:

[0023] 1. The swirl combustion device and method of the present application can effectively prevent slagging at the outlet of the pre - combustion chamber:

[0024] When burning easily slagging coal, if there is a large - scale recirculation zone in the pre - combustion chamber, it will cause the ignition position of pulverized coal to move forward. The combustion time of pulverized coal in the pre - combustion chamber is long, and a large amount of energy is released, resulting in too high a temperature in the pre - combustion chamber, which in turn leads to slagging at the outlet of the pre - combustion chamber. If there is a small - scale recirculation zone in the pre - combustion chamber, the intense combustion process of pulverized coal is shifted to the furnace, but it will increase the difficulty of pulverized coal ignition. Therefore, the length of the pre - combustion chamber needs to be adjusted according to the slagging characteristics of the coal type being burned and the temperature in the pre - combustion chamber to make there be a suitable - scale recirculation zone in the pre - combustion chamber.

[0025] When the slagging tendency of the pre - combustion chamber is serious (ST≤1260 °C or T1>850 °C), the length of the pre - combustion chamber is reduced (L = 0.8 - 1.0D), so that there is a small - scale recirculation zone in the pre - combustion chamber (m = 0.6 - 0.7D, d = 0.5 - 0.6D). At this time, the amount of high - temperature flue gas entrained by the recirculation zone is small, the ignition of pulverized coal is late, the combustion time of pulverized coal in the pre - combustion chamber is short, the heat released is small, and the temperature in the pre - combustion chamber is 1000 - 1100 °C. At this time, the pulverized coal will not slag and melt in the pre - combustion chamber, and slagging can be effectively prevented. At the same time, the recirculation zone is far from the burner nozzle (m1 = 0.15 - 0.25D) to prevent the recirculation zone from being too close to the nozzle and causing burnout. When the slagging tendency of the pre - combustion chamber is slight (ST>1390 °C or 800≥T1>150 °C or 200≥T2>150 °C), the length of the pre - combustion chamber is increased (L = 1.2 - 1.4D), so that there is a large - scale recirculation zone in the pre - combustion chamber (m = 1.0 - 1.15D, d = 0.8 - 0.85D). At this time, the amount of high - temperature flue gas entrained by the recirculation zone is large, which can ensure the timely ignition of pulverized coal. The temperature in the pre - combustion chamber is 1200 - 1300 °C, and the pulverized coal will not slag and melt in the pre - combustion chamber, and slagging can be effectively prevented. The starting position of the recirculation zone is close to the burner nozzle (m1 = 0.05 - 0.1D) to ignite the pulverized coal in time. When the slagging tendency of the pre - combustion chamber is medium (ST = 1260 - 1390 °C or 850≥T1>800 °C or T2>200 °C), the length of the pre - combustion chamber is adjusted (L = 1.0 - 1.2D), so that there is a suitable - scale recirculation zone in the pre - combustion chamber (m1 = 0.1 - 0.15D, m = 0.7 - 1.0D, d = 0.6 - 0.8D). The temperature in the pre - combustion chamber is 1100 - 1200 °C, which can prevent slagging and burnout of the burner and the pre - combustion chamber nozzle while ensuring the ignition performance of pulverized coal.

[0026] Second, by moving the pre - combustion chamber, the slagged blocks are cleaned up.

[0027] By using the device of the present invention, the slagging condition at the outlet of the pre-combustion chamber can be monitored through DSC. When slagging is observed at the outlet of the pre-combustion chamber, the pull rod is adjusted to make the pre-combustion chamber expand and contract, and the slag blocks near the outlet of the pre-combustion chamber (m2 = 0 - 0.4D) are shaken off. By utilizing the advantage of the movable pre-combustion chamber, the accumulation of slag blocks can be prevented to the greatest extent, avoiding large slag blocks from falling and damaging the cold ash hopper at the bottom of the furnace or the water-cooled wall pipes of the furnace, and ensuring the safe operation of the boiler.

[0028] III. Check the slagging condition and the flame combustion state through the temperature sensor and the video flame detector

[0029] Under the condition of only having a temperature sensor, it is difficult to accurately grasp the actual slagging situation only based on the temperature information. If only through video monitoring, the slagging trend cannot be predicted. By using the device of the present invention, the temperature data measured by the temperature sensor can be read through the DSC interface to realize real-time temperature monitoring. At the same time, through the DSC, a clear picture captured by the video flame detector can be directly observed to check the slagging condition and the flame combustion state in the pre-combustion chamber, thereby realizing multi-dimensional and all-round observation of the pre-combustion chamber condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the front view of the overall structure of this application.

[0031] Figure 2 It is Figure 1 the sectional view taken along the line A-A of

[0032] Figure 3 It is the schematic diagram of the principle of the video flame detector.

[0033] Figure 4 It is the schematic diagram of the principle of the temperature sensor.

[0034] Figure 5 It is the schematic diagram of the position and size of the central recirculation zone in the adjustable pre-combustion chamber of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] Detailed Description 1: In combination with Figure 1 - Figure 2 to illustrate this embodiment, the swirl combustion device with an adjustable aspect ratio of the pre-combustion chamber described in this embodiment includes a primary air duct 1, an inner secondary air duct 2, an outer secondary air duct 3, and a separated secondary air duct 6; it also includes a video flame detector 4, an outlet temperature sensor 5, a barrel wall temperature sensor 7, and an adjustable pre-combustion chamber 20;

[0036] The primary air duct 1, the inner secondary air duct 2, and the outer secondary air duct 3 are arranged in sequence from the inside out. The outlets of the primary air duct 1, the inner secondary air duct 2, and the outer secondary air duct 3 are all communicated with the combustion chamber of the adjustable pre-chamber 20. The driving part of the adjustable pre-chamber 20 is installed outside the outer secondary air duct 3. The separation secondary air duct 6 is sleeved outside the outer secondary air duct 3 and the combustion chamber of the adjustable pre-chamber 20. The length of the combustion chamber of the adjustable pre-chamber 20 is adjusted along the axial direction of the outer secondary air duct 3. The video flame detector 4, the outlet temperature sensor 5, and the cylinder wall temperature sensor 7 are installed on the combustion chamber of the adjustable pre-chamber 20.

[0037] In this embodiment, inner secondary air vanes 2-1 are arranged at the outlet of the inner secondary air duct 2, outer secondary air vanes 3-1 are arranged at the outlet of the outer secondary air duct 3, and separation secondary air vanes 6-1 are arranged at the outlet of the separation secondary air duct 6.

[0038] Specific Embodiment Two: Combined with Figure 1 、 Figure 2 This embodiment is described. The swirl combustion device with an adjustable pre-chamber aspect ratio described in this embodiment, the combustion chamber of the adjustable pre-chamber 20 includes a pre-chamber inner sleeve 14 and a pre-chamber outer sleeve 15;

[0039] The outlet end of the pre-chamber outer sleeve 15 is installed at the inlet of the furnace 19 and is communicated with the furnace 19. The pre-chamber inner sleeve 14 is slidably arranged inside the pre-chamber outer sleeve 15. The outlets of the primary air duct 1, the inner secondary air duct 2, and the outer secondary air duct 3 are all communicated with the pre-chamber inner sleeve 14. The outlet end of the pre-chamber outer sleeve 15 is installed flush with the furnace 19. Other methods are the same as those in Specific Embodiment One.

[0040] Specific Embodiment Three: Combined with Figure 1 、 Figure 2 This embodiment is described. The swirl combustion device with an adjustable pre-chamber aspect ratio described in this embodiment, a plurality of slide rails 16 are arranged along the length direction on the inner wall of the pre-chamber outer sleeve 15, and limiters 18 are installed at both ends of each slide rail 16. At least two rows of rollers 17 are arranged on the outer wall of the outlet of the pre-chamber inner sleeve 14. The pre-chamber inner sleeve 14 is slidably arranged on the slide rails 16 of the pre-chamber outer sleeve 15 through the rollers 17. Other methods are the same as those in Specific Embodiment Two.

[0041] Specific Embodiment Four: Combined with Figure 1 、 Figure 2 This embodiment is described. The swirl combustion device with an adjustable pre-chamber aspect ratio described in this embodiment, the driving part of the adjustable pre-chamber 20 includes a bracket 12, two tie rods 9, two connecting mechanisms 13, four limit nuts 10, and four gaskets 11;

[0042] Two pull rods 9 are oppositely arranged on the bracket 12. The pull rods 9 are processed with threaded sections. The threaded section of each pull rod 9 is arranged on the bracket 12, and two limit nuts 10 are threadedly connected to the threaded section of each pull rod 9. The two limit nuts 10 are located on both sides of the bracket 12. A gasket 11 is provided between each limit nut 10 and the bracket 12. One end of each pull rod 9 is connected to the pre-combustion chamber inner sleeve 14 through a connecting mechanism 13. Pulling the pull rod 9 can adjust the position of the pre-combustion chamber inner sleeve 14 within the pre-combustion chamber outer sleeve 15. A scale 8 is provided on the bracket 12, and the scale 8 is used to observe the position of the adjustable pre-combustion chamber 20. Tighten the limit nut 10 at the required position to fix the pull rod 9 on the bracket 12, thereby realizing the adjustment of the length of the adjustable pre-combustion chamber 20. By adjusting the length of the adjustable pre-combustion chamber 20, the range of the recirculation zone in the pre-combustion chamber is controlled. The range of the recirculation zone includes the length and diameter of the recirculation zone. Other methods are the same as those in the third specific embodiment.

[0043] Specific embodiment five: Combining Figure 1 , Figure 2 to illustrate this embodiment. In this embodiment, for a swirl combustion device with an adjustable pre-combustion chamber aspect ratio, the video flame detector 4 is installed on the pre-combustion chamber inner sleeve 14 near the outlet of the outer secondary air duct 3. An outlet temperature sensor 5 is installed on the pre-combustion chamber inner sleeve 14 near the connecting mechanism 13. A barrel wall temperature sensor 7 is installed on the pre-combustion chamber outer sleeve 15 near the furnace wall of the furnace 19. The video flame detector 4 is composed of a high-temperature probe, a camera system, a cooling and protection device, a thruster, a power control box, a gas source filtering and pressure control box, and a monitor, and is connected to the DCS system through a cable. The probe and the camera system are installed horizontally. When a picture needs to be taken, control the thruster to extend the probe, the camera system, and the cooling and protection device from the connector into the pre-combustion chamber. The camera system sends the obtained video signal to the controller, and the controller sends the received video signal to the DSC to monitor the slagging and flame combustion conditions in the pre-combustion chamber through the DSC. As Figure 3 shown, the specific steps are as follows: First step, open the purge and cooling gas valve and confirm that the air pressure in the gas source control box reaches the protection pressure; Second step, open the door of the power control box, check the circuit is correct and then close the air switch; Third step, adjust the monitor to the "video" state, and press the "in" button on the centralized control room operator. When the indicator light is on, it means that the thruster has advanced in place; Finally, after the probe enters the working position, the picture displayed on the monitor is the furnace condition that needs to be observed. The temperature sensor is fixed through the support pipe on the outer wall of the pre-combustion chamber, and part of the temperature measuring element and the protection sleeve extend into the inner wall of the pre-combustion chamber for temperature measurement. The temperature measuring element can transmit the temperature signal to the DSC in real time, and the temperature information at the outlet and the barrel wall position of the pre-combustion chamber is monitored through the DSC. Other methods are the same as those in the second specific embodiment.

[0044] Specific embodiment six: Combining Figure 1 - Figure 5Description of this embodiment, the swirling combustion method of a swirling combustion device with an adjustable length-diameter ratio of a pre-chamber, the method is implemented according to the following steps:

[0045] Step 1: According to the softening temperature ST of the coal used, the temperature T1 of the outlet temperature sensor 5, and the temperature T2 of the cylinder wall temperature sensor 7, combined with slagging, adjust the recirculation zone in the adjustable pre-chamber 20, and adjust the ratios of the distance m1 between the burner outlet and the starting point of the recirculation zone, the recirculation zone length m, and the recirculation zone diameter d to the pre-chamber diameter respectively;

[0046] Step 2: And through the DSC of the boiler, observe the slagging situation at the outlet of the adjustable pre-chamber 20, and control the adjustable length-diameter ratio of the adjustable pre-chamber 20 to clean the slag blocks of the slagging.

[0047] Specific embodiment seven: Combine Figure 1 - Figure 5 Description of this embodiment, the swirling combustion method of a swirling combustion device with an adjustable length-diameter ratio of a pre-chamber,

[0048] In the first method of Step 1: When the softening temperature ST of the coal being burned > 1390 °C, or 800 °C ≥ the temperature T1 of the outlet temperature sensor 5 > 150 °C, or 200 ≥ the temperature T2 of the cylinder wall temperature sensor 7 > 150 °C, and when the thickness of the slag layer of the slagging is between 0 - 30 mm, a large-scale recirculation zone is required in the pre-chamber. Therefore, pull the pull rod 9 to adjust the position of the inner sleeve 14 in the pre-chamber, so that L = 1.2 - 1.4, where L is the length of the pre-chamber, and make m1 = 0.05 - 0.1D, m = 1.0 - 1.15D, d = 0.8 - 0.85D for the central recirculation zone in the pre-chamber. Other methods are the same as those in Specific Embodiment Six.

[0049] Specific embodiment eight: Combine Figure 1 - Figure 5 Description of this embodiment, the swirling combustion method of a swirling combustion device with an adjustable length-diameter ratio of a pre-chamber,

[0050] In the second method of Step 1: When the softening temperature ST of the coal being burned is between 1260 - 1390 °C, or 850 ≥ the temperature T1 of the outlet temperature sensor 5 > 800 °C, or the temperature T2 of the cylinder wall temperature sensor 7 > 200 °C, and when the thickness of the slag layer of the slagging is between 30 - 100 mm, a large-scale recirculation zone is required in the pre-chamber. Therefore, pull the pull rod 9 to adjust the position of the inner sleeve 14 in the pre-chamber, so that L = 1.0 - 1.2D, where L is the length of the pre-chamber, and make m1 = 0.1 - 0.15D, m = 0.7 - 1.0D, d = 0.6 - 0.8D for the central recirculation zone in the pre-chamber. Other methods are the same as those in Specific Embodiment Six.

[0051] Specific embodiment nine: Combine Figure 1 - Figure 5Description of this embodiment, the swirling combustion method of a swirling combustion device with an adjustable pre-combustion chamber aspect ratio described in this embodiment

[0052] Method 3 in Step 1: When the softening temperature ST of the coal being burned is less than or equal to 1260, or the temperature T1 of the outlet temperature sensor 5 > 850 °C, and the thickness of the slagging layer is greater than 100 mm, and the slagging tendency is serious, a small range of recirculation zone is required in the pre-combustion chamber. Therefore, pull the rod 9 to adjust the position of the inner sleeve 14 in the pre-combustion chamber, so that L = 0.8 - 1.0D, where L is the length of the pre-combustion chamber, and make m1 = 0.15 - 0.25D, m = 0.6 - 0.7D, d = 0.5 - 0.6D in the central recirculation zone of the pre-combustion chamber. Other methods are the same as those in Specific Embodiment 6.

[0053] Specific Embodiment 10: Combine Figure 1 - Figure 5 Description of this embodiment, the swirling combustion method of a swirling combustion device with an adjustable pre-combustion chamber aspect ratio described in this embodiment. In Step 2, the slag blocks are cleaned by controlling the adjustable aspect ratio of the adjustable pre-combustion chamber 20. Pull the rod 9 to make the inner sleeve 14 in the pre-combustion chamber telescopic in the outer sleeve 15 of the pre-combustion chamber, and shake off the slag blocks. Other methods are the same as those in Specific Embodiment 6.

[0054] The pulverized coal-air mixture enters the adjustable pre-combustion chamber 20 through the primary air duct 1. The inner secondary air in the inner secondary air duct 2 forms a swirling airflow after passing through the inner secondary air vanes 2-1; the outer secondary air in the outer secondary air duct 3 forms a swirling airflow after passing through the outer secondary air vanes 3-1, and the direction of rotation of this airflow is the same as that of the airflow in the inner secondary air duct 2; the separated secondary air in the separated secondary air duct 6 forms a swirling airflow after passing through the separated secondary air vanes 6-1, and the direction of rotation of this airflow is the same as that of the airflow in the inner secondary air duct 2. The direct-flow primary air-powder airflow enters the adjustable pre-combustion chamber 20 and quickly diffuses into the outer secondary air region under the entrainment of the swirling inner secondary air airflow, and mixes with the swirling outer secondary air. The swirling inner secondary air airflow and the outer secondary air airflow with the same rotation direction mix to form a large-scale central recirculation zone in the pre-combustion chamber. The swirling separated secondary air moves around the furnace perimeter and mixes with the high-temperature flue gas in the furnace to supplement the air required for the burnout of the pulverized coal.

[0055] Pull the rod 9 to adjust the position of the inner sleeve 14 in the pre-combustion chamber, change the length of the adjustable pre-combustion chamber 20, and the scale 8 on the support 12 is used to observe the position of the pre-combustion chamber. Tighten the limit nut 10 at the required position to fix the rod 9 on the support 11, thereby fixing the length of the adjustable pre-combustion chamber 20. By controlling the length of the pre-combustion chamber, the range of the recirculation zone in the pre-combustion chamber is controlled.

[0056] The above specific embodiments can be locally adjusted in different ways by those skilled in the art without departing from the principles and purposes of the present invention. The protection scope of the present invention is subject to the claims and is not limited by the above specific embodiments. All implementation solutions within its scope are subject to the present invention.

Claims

1. A swirl combustion device with an adjustable pre-chamber aspect ratio, which comprises a primary air duct (1), an inner secondary air duct (2), an outer secondary air duct (3) and a separated secondary air duct (6); characterized in that: It also includes a video flame detector (4), an outlet temperature sensor (5), a cylinder wall temperature sensor (7), and an adjustable pre - combustion chamber (20); the combustion chamber of the adjustable pre - combustion chamber (20) includes a pre - combustion inner sleeve (14) and a pre - combustion outer sleeve (15); the driving part of the adjustable pre - combustion chamber (20) includes a bracket (12), two tie rods (9), two connecting mechanisms (13), four limit nuts (10), and four gaskets (11); The primary air duct (1), the inner secondary air duct (2), and the outer secondary air duct (3) are arranged in sequence from inside to outside. The outlet of the primary air duct (1), the outlet of the inner secondary air duct (2), and the outlet of the outer secondary air duct (3) are all communicated with the combustion chamber of the adjustable pre - combustion chamber (20). The driving part of the adjustable pre - combustion chamber (20) is installed outside the outer secondary air duct (3). The separated secondary air duct (6) is sleeved outside the outer secondary air duct (3) and the combustion chamber of the adjustable pre - combustion chamber (20). The length of the combustion chamber of the adjustable pre - combustion chamber (20) is adjusted along the axial direction of the outer secondary air duct (3). The video flame detector (4), the outlet temperature sensor (5), and the cylinder wall temperature sensor (7) are installed on the combustion chamber of the adjustable pre - combustion chamber (20). The outlet end of the pre - combustion outer sleeve (15) is installed at the inlet of the furnace (19) and is communicated with the furnace (19). The pre - combustion inner sleeve (14) is slidably arranged inside the pre - combustion outer sleeve (15). The outlet of the primary air duct (1), the outlet of the inner secondary air duct (2), and the outlet of the outer secondary air duct (3) are all communicated with the pre - combustion inner sleeve (14). A plurality of slide rails (16) are arranged along the length direction of the inner wall of the pre - combustion outer sleeve (15), and limiters (18) are installed at both ends of each slide rail (16). At least two rows of rollers (17) are arranged on the outer wall of the outlet of the pre - combustion inner sleeve (14). The pre - combustion inner sleeve (14) is slidably arranged on the slide rails (16) of the pre - combustion outer sleeve (15) through the rollers (17). The two tie rods (9) are oppositely arranged on the bracket (12). The tie rods (9) are processed with threaded sections. The threaded section of each tie rod (9) is arranged on the bracket (12), and two limit nuts (10) are threadedly connected to the threaded section of each tie rod (9). The two limit nuts (10) are located on both sides of the bracket (12). A gasket (11) is arranged between each limit nut (10) and the bracket (12). One end of each tie rod (9) is connected to the pre - combustion inner sleeve (14) through a connecting mechanism (13).

2. The swirl combustion device with an adjustable pre-chamber aspect ratio according to claim 1, characterized in that: The video flame detector (4) is installed on the pre - combustion inner sleeve (14) near the outlet of the outer secondary air duct (3). The outlet temperature sensor (5) is installed on the pre - combustion inner sleeve (14) near the connecting mechanism (13). The cylinder wall temperature sensor (7) is installed on the furnace wall of the pre - combustion outer sleeve (15) near the furnace (19).

3. A swirl combustion method for a swirl combustion device with an adjustable pre-combustion chamber aspect ratio, characterized in that: The method is realized according to the following steps: Step 1: Based on the softening temperature ST of the coal used, the temperature T1 of the outlet temperature sensor (5), and the temperature T2 of the cylinder wall temperature sensor (7), adjust the recirculation zone in the adjustable pre-combustion chamber (20) in combination with slagging, and adjust the ratios of the distance m1 between the burner outlet and the starting point of the recirculation zone, the recirculation zone length m, and the recirculation zone diameter d to the pre-combustion chamber diameter respectively. Step 2: Observe the slagging condition at the outlet of the adjustable pre-combustion chamber (20) through the DSC of the boiler, and control the adjustable aspect ratio of the adjustable pre-combustion chamber (20) to clean the slag blocks of the slagging.

4. The swirl combustion method of a swirl combustion device with an adjustable aspect ratio of the pre-combustion chamber according to claim 3, characterized in that: In Step 1, Method 1: When the softening temperature ST of the coal used > 1390 °C, or 800 °C ≥ the temperature T1 of the outlet temperature sensor (5) > 150 °C, or 200 ≥ the temperature T2 of the cylinder wall temperature sensor (7) > 150 °C, and the slagging layer thickness is in the range of 0 - 30 mm, a large-scale recirculation zone is required in the pre-combustion chamber. Therefore, pull the pull rod (9) to adjust the position of the inner sleeve (14) in the pre-combustion chamber, so that L = 1.2 - 1.4, where L is the length of the pre-combustion chamber, and make m1 = 0.05 - 0.1D, m = 1.0 - 1.15D, d = 0.8 - 0.85D for the central recirculation zone in the pre-combustion chamber.

5. The swirl combustion method of a swirl combustion device with an adjustable aspect ratio of the pre-combustion chamber according to claim 3, characterized in that: In Step 1, Method 2: When the softening temperature ST of the coal used is between 1260 - 1390 °C, or 850 ≥ the temperature T1 of the outlet temperature sensor (5) > 800 °C, or the temperature T2 of the cylinder wall temperature sensor (7) > 200 °C, and the slagging layer thickness is in the range of 30 - 100 mm, a large-scale recirculation zone is required in the pre-combustion chamber. Therefore, pull the pull rod (9) to adjust the position of the inner sleeve (14) in the pre-combustion chamber, so that L = 1.0 - 1.2D, where L is the length of the pre-combustion chamber, and make m1 = 0.1 - 0.15D, m = 0.7 - 1.0D, d = 0.6 - 0.8D for the central recirculation zone in the pre-combustion chamber.

6. The swirl combustion method of a swirl combustion device with an adjustable aspect ratio of the pre-combustion chamber according to claim 3, characterized in that: In Step 1, Method 3: When the softening temperature ST of the coal used is less than or equal to 1260, or the temperature T1 of the outlet temperature sensor (5) > 850 °C, and the slagging layer thickness is greater than 100 mm, a small-scale recirculation zone is required in the pre-combustion chamber. Therefore, pull the pull rod (9) to adjust the position of the inner sleeve (14) in the pre-combustion chamber, so that L = 0.8 - 1.0D, where L is the length of the pre-combustion chamber, and make m1 = 0.15 - 0.25D, m = 0.6 - 0.7D, d = 0.5 - 0.6D for the central recirculation zone in the pre-combustion chamber.

7. The swirl combustion method of a swirl combustion device with an adjustable pre-chamber aspect ratio according to claim 3, characterized in that: In Step 2, control the adjustable aspect ratio of the adjustable pre-combustion chamber (20) to clean the slag blocks of the slagging. Pull the pull rod (9) to make the inner sleeve (14) of the pre-combustion chamber telescopic in the outer sleeve (15) of the pre-combustion chamber, and shake off the slag blocks.

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