A three-dimensional composite tangential combustion system suitable for a pulverized coal boiler burning strongly slagging coal

Abstract

The application provides a three-dimensional composite tangential combustion system suitable for a strong slagging coal-fired pulverized coal boiler, which is arranged on a boiler body, the width dimension of the boiler body is W, the depth dimension of the boiler body is D, and the three-dimensional composite tangential combustion system comprises: at least two groups of main burner groups arranged in the up-down direction of the height of a furnace, which are arranged at the corners of the lower part of the furnace and form a clockwise rotating tangential combustion; the three-dimensional composite tangential combustion system has the beneficial effects that: the main burner groups are at least two groups, compared with a single group arrangement mode, the height-width ratio is obviously reduced, the air supplement conditions on both sides of the outlet airflow of the burner can be balanced, the airflow rigidity and the stability of the combustion fireball are improved, and the excessive diffusion of the combustion tangential circle is reduced.

Description

Technical Field

[0001] This invention relates to the field of boiler combustion technology, and in particular to a three-dimensional composite tangential combustion system suitable for pulverized coal boilers that burn strongly slagging coal. Background Technology

[0002] In coal-fired power generating units, coal, as fuel, plays a crucial role in the design and operation of the boiler. Different coal qualities often have different characteristics. Slagging tendency is an important indicator for judging coal quality characteristics. Coal with strong slagging tendency has an adverse effect on the safe operation of the boiler. Therefore, targeted measures must be taken during the boiler design process to minimize slagging problems in the furnace. High-alkali coal has a very strong slagging tendency, far exceeding that of common coal types from other regions that are prone to slagging. Currently, practitioners in my country's power plant boiler field have accumulated a lot of useful experience and achieved certain results in dealing with high-alkali coal. By reducing the furnace heat load level, controlling the furnace outlet flue gas temperature, and reasonably adding soot blowing equipment, the boiler's anti-slagging ability has been significantly improved. However, existing technical measures have not yet completely solved the furnace slagging problem in boilers burning high-alkali coal. The design of each boiler system needs to be carefully considered, and further development of highly operable, effective, and economical technical measures is needed to improve the anti-slagging ability of pulverized coal boilers burning highly slagging coal. Summary of the Invention

[0003] To overcome the aforementioned problems in the prior art, the present invention provides a three-dimensional composite tangential combustion system suitable for pulverized coal boilers burning strongly slagging coal.

[0004] This invention discloses a three-dimensional composite tangential combustion system suitable for pulverized coal boilers burning strongly slagging coal, arranged on the boiler body, the boiler body having a width dimension W and a depth dimension D, characterized in that it includes:

[0005] At least two main burner groups are arranged vertically along the height of the furnace, located at the lower corners of the furnace, forming a clockwise rotating tangential combustion. An intermediate layer burner is arranged on the four walls of the boiler body above the main burner groups, including a combustion-promoting nozzle and an intermediate air box. Its outlet airflow direction forms an angle with the boiler wall, creating a clockwise rotating imaginary tangential circle. A rectifier burner is arranged on the four walls of the boiler body above the intermediate layer burner, including a rectifier nozzle and a rectifier air box. Its outlet airflow direction is towards the center of the furnace, forming a counterclockwise rotating imaginary tangential circle. The counter-current airflow of the rectifier burner is used to counteract the clockwise rotating airflow generated by the main burner and the intermediate layer burner.

[0006] Based on this, one arrangement of the main burner group includes a lower main burner group and an upper main burner group arranged in the height direction of the furnace, and the main burner group is respectively equipped with multiple layers of pulverized coal nozzles and corresponding secondary air nozzles.

[0007] Based on this, another arrangement of the main burner group includes a lower main burner group, a middle main burner group, and an upper main burner group arranged in the height direction of the furnace. The main burner group is respectively equipped with multi-layer pulverized coal nozzles and corresponding secondary air nozzles.

[0008] Based on this, in the lower main burner, the distances between adjacent pulverized coal nozzles from bottom to top are H1 and H2, respectively, 0≤(H2-H1)≤450mm; the distance between the uppermost pulverized coal nozzle in the lower main burner and the lowermost pulverized coal nozzle in the upper main burner is H3, 2.5m≤H3≤6m; in the upper main burner, the distances between adjacent pulverized coal nozzles from bottom to top are H4 and H5, respectively, 0≤(H5-H4)≤400mm; the distance between the intermediate burner and the uppermost pulverized coal nozzle in the upper main burner is H6, 2m≤H6≤10m; the distance between the rectifier burner and the intermediate burner is H7, 3m≤H7≤12m; and H1≤H2<H4≤H5, 0<(H4-H2)≤500mm.

[0009] Based on this, the distance between the lowest pulverized coal nozzle of the lower main burner group and the highest pulverized coal nozzle of the upper main burner group is H; the spacing between adjacent pulverized coal nozzles in the lower main burner group is H1; the distance between adjacent pulverized coal nozzles in the middle main burner group is H3; and the distance between adjacent pulverized coal nozzles in the upper main burner group is H5, where H1 < H3 < H5, and 0 < (H3 - H1) ≤ 550 mm, 0 < (H5 - H3) ≤ 500 mm; the lower group The distance between the uppermost pulverized coal nozzle of the main burner and the lowermost pulverized coal nozzle of the middle main burner is H2, where 2.5m ≤ H2 ≤ 6m; the distance between the uppermost pulverized coal nozzle of the middle main burner and the lowermost pulverized coal nozzle of the upper main burner is H4, where 2.5m ≤ H4 ≤ 6m; and 0 ≤ (H4 - H2) ≤ 500mm; the distance between the intermediate burner and the uppermost pulverized coal nozzle of the upper main burner is H6, and the distance between the rectifier burner and the intermediate burner is H7.

[0010] Based on this, the center line of the pulverized coal nozzle in the lower burner is aligned with the center line of the main burner group's air box outlet, forming an angle α with the diagonal of the boiler body cross-section. The center line of the pulverized coal nozzle in the upper burner is aligned with the center line of the main burner group's air box outlet, forming an angle β with the diagonal of the boiler body cross-section. The range of α is 0°-4°, the range of β is 0°-3°, and 1°≤(α-β)≤4°. The airflow direction at the outlet of the secondary air nozzle in the lower burner forms an angle θ with the center line of the pulverized coal nozzle, with the range of θ being 0°-20°. The airflow direction at the outlet of the secondary air nozzle in the upper burner forms an angle λ with the center line of the pulverized coal nozzle, with the range of λ being 0°-20°. The center line of the outlet of the intermediate air box of the intermediate layer burner is aligned with the center line of the outlet of the combustion-promoting nozzle, forming an angle ρ with the boiler body wall, with 45°≤ρ≤135°.

[0011] Based on this, the centerline of the pulverized coal nozzle in the lower burner group is aligned with the centerline of the main burner group's air box outlet, forming an angle α with the diagonal of the boiler body cross-section. Similarly, the centerline of the pulverized coal nozzle in the middle burner group is aligned with the centerline of the main burner group's air box outlet, forming an angle β with the diagonal of the boiler body cross-section. The range of α is 0°-4°, and the range of β is 0°-3°, with 1°≤(α-β)≤4°. The airflow direction at the outlet of the secondary air nozzle in the lower burner group forms an angle θ with the centerline of the pulverized coal nozzle, where θ ranges from 0° to 4°. °-20°; the airflow direction at the outlet of the secondary air nozzle in the middle burner forms an angle λ with the center line of the pulverized coal nozzle, and λ ranges from 0° to 20°; the airflow direction at the outlet of the secondary air nozzle in the lower burner forms an angle τ with the center line of the pulverized coal nozzle, and τ ranges from 0° to 20°; the center line of the pulverized coal nozzle in the upper burner is consistent with the center line of the main burner group air box outlet, and forms an angle ω with the diagonal of the boiler body section, and ω ranges from 0° to 2°, and 1°≤(α-β)≤4°, 1°≤(β-ω)≤3°.

[0012] Based on this, the distance between the positioning point of the intermediate layer burner and the adjacent wall of the boiler body is L1, 1.5m≤L1≤W / 3, and the distance between the positioning point of the rectifier burner and the center line of the boiler body section is L2, W / 8≤L2≤W / 4.

[0013] Based on this, the center line of the intermediate air box outlet of the intermediate layer burner is aligned with the center line of the combustion-promoting nozzle outlet, and the angle between the intermediate layer burner and the boiler body wall is ρ, where 45°≤ρ≤135°.

[0014] Another aspect of the present invention discloses a pulverized coal boiler equipped with the aforementioned three-dimensional composite tangential combustion system.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] The main burner group of this invention comprises at least two groups. Compared to a single-group arrangement, the aspect ratio is significantly reduced, which can balance the air supply conditions on both sides of the burner outlet airflow, improve airflow rigidity and combustion fireball stability, and reduce excessive diffusion of the combustion tangential circle. From bottom to top, the total spacing between the pulverized coal nozzles of the main burner group increases, meaning the wall heat load in the lower region is higher than that in the upper region; the imaginary tangential circle of the main burner group decreases, meaning the hot tangential circle and turbulence intensity of the lower main burner are greater than those of the upper main burner. The imaginary tangential circle diameter of the main burner region is larger at the bottom and smaller at the top, while the primary air spacing is smaller at the bottom and larger at the top. This precise zoning design, combined with the temperature field characteristics of the gradually increasing flue gas temperature along the furnace height direction and the aerodynamic field characteristics of the gradually increasing diameter of the combustion hot tangential circle in the furnace cross-section, forms a benign compensation and dynamic balance, which is beneficial for preventing furnace slagging. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the boiler body structure according to Embodiment 1 of the present invention;

[0018] Figure 2 This is a schematic diagram of the three-dimensional composite tangential combustion system structure of Embodiment 1 of the present invention;

[0019] Figure 3 yes Figure 2 AA view;

[0020] Figure 4 yes Figure 2 BB view;

[0021] Figure 5 yes Figure 2 CC view;

[0022] Figure 6 yes Figure 2 DD-direction view;

[0023] Figure 7 This is a schematic diagram of the boiler body structure in Embodiment 2 of the present invention;

[0024] Figure 8 This is a schematic diagram of the three-dimensional composite tangential combustion system structure of Embodiment 2 of the present invention.

[0025] Figure 9 yes Figure 8 EE view;

[0026] In the picture:

[0027] Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0029] Example 1

[0030] refer to Figures 1-6 Taking a 600MW-class pulverized coal boiler as an example, this invention discloses a three-dimensional composite tangential combustion system suitable for pulverized coal boilers burning strongly slagging coal. The system is arranged on the boiler body 11, where the width W and depth D of the boiler body 11 are the same. The boiler body 11 employs four-corner tangential combustion technology. The three-dimensional composite tangential combustion system includes: at least two main burner groups arranged vertically along the furnace height, with the main burner groups located at the lower corners of the furnace, forming clockwise rotating tangential combustion; and an intermediate layer of burners... The furnace walls above the main burners include combustion nozzles 8 and intermediate air boxes 7, with the outlet airflow direction forming an angle with the boiler wall, creating an imaginary tangent circle rotating clockwise. The rectifier burners, arranged on the furnace walls above the intermediate burners, include rectifier nozzles 9 and rectifier air boxes 10, with the outlet airflow direction perpendicular to the boiler body wall 11, creating an imaginary tangent circle rotating counterclockwise. The counter-current airflow of the rectifier burners is used to counteract the clockwise rotating airflow generated by the main burner group and the intermediate burners.

[0031] The main burner group includes a lower main burner group and an upper main burner group arranged in the height direction of the furnace. The main burner group is equipped with multi-layer pulverized coal nozzles 2 and 5 and corresponding secondary air nozzles 1 and 4.

[0032] In this embodiment, the pulverizing system is equipped with six coal mills; the three coal mills correspond to three layers of pulverized coal nozzles 2, several secondary air nozzles 1, and main burner group air boxes 3 to form the lower main burner group, which is arranged at the four corners of the lower part of the boiler body 11; the other three coal mills correspond to three layers of pulverized coal nozzles 5, several secondary air nozzles 4, and main burner group air boxes 6 to form the upper main burner group, which is arranged at the four corners of the lower upper part of the boiler body 11.

[0033] In the lower main burner group, the distances between adjacent pulverized coal nozzles 2 from bottom to top are H1 and H2, respectively, with 0 ≤ (H2-H1) ≤ 450 mm; the distance between the uppermost pulverized coal nozzle 2 in the lower main burner group and the lowermost pulverized coal nozzle 5 in the upper main burner group is H3, with 2.5 m ≤ H3 ≤ 6 m; in the upper main burner group, the distances between adjacent pulverized coal nozzles 5 from bottom to top are H4 and H5, respectively, with 0 ≤ (H5-H4) ≤ 400 mm; the distance between the intermediate burner and the uppermost pulverized coal nozzle 5 in the upper main burner group is H6, with 2 m ≤ H6 ≤ 10 m; the distance between the rectifier burner and the intermediate burner group is H7, with 3 m ≤ H7 ≤ 12 m; and H1 ≤ H2 < H4 ≤ H5, with 0 < (H4-H2) ≤ 500 mm.

[0034] In the lower burner, the center line of the pulverized coal nozzle 2 is aligned with the center line of the main burner group air box 3 outlet, forming an angle α with the diagonal of the boiler body 11 cross section. In the upper burner, the center line of the pulverized coal nozzle 5 is aligned with the center line of the main burner group air box 6 outlet, forming an angle β with the diagonal of the boiler body 11 cross section. The range of α is 0°-4°, the range of β is 0°-3°, and 1°≤(α-β)≤4°. In the lower burner, the outlet airflow direction of the secondary air nozzle 1 forms an angle θ with the center line of the pulverized coal nozzle 2, with the range of θ being 0°-20°. In the upper burner, the outlet airflow direction of the secondary air nozzle (4) forms an angle λ with the center line of the pulverized coal nozzle 5, with the range of λ being 0°-20°. In the intermediate layer burner, the outlet center line of the intermediate air box 7 is aligned with the outlet center line of the combustion-promoting nozzle 8, forming an angle ρ with the wall of the boiler body 11, with 45°≤ρ≤135°.

[0035] The distance between the positioning point of the intermediate layer burner and the adjacent wall of the boiler body 11 is L1, 1.5m≤L1≤W / 3, and the distance between the positioning point of the rectifier burner and the center line of the cross section of the boiler body 11 is L2, W / 8≤L2≤W / 4.

[0036] The center line of the outlet of the intermediate air box 7 of the intermediate layer burner is aligned with the center line of the outlet of the combustion-promoting nozzle 8, and the angle between the intermediate air box 7 and the wall of the boiler body 11 is ρ, where 45°≤ρ≤135°.

[0037] In this embodiment, the main burner group is divided into two groups. Compared with the single-group arrangement, the aspect ratio is significantly reduced, which can balance the gas supply conditions on both sides of the burner outlet airflow, improve the airflow rigidity and the stability of the combustion fireball, and reduce the excessive diffusion of the combustion tangential circle.

[0038] In the design, the total spacing of the pulverized coal nozzles in the lower main burner group is smaller than that in the upper main burner group, meaning the wall heat load in the lower main burner group is higher than that in the upper main burner group. The imaginary tangent circle of the lower main burner group is larger than that of the upper main burner group, meaning the hot tangent circle and turbulence intensity of the lower main burner group are greater than those of the upper main burner group. The imaginary tangent circle diameter of the main burner group is larger at the bottom and smaller at the top, while the primary air spacing is smaller at the bottom and larger at the top. This precise zoning design, combined with the temperature field characteristics of the gradually increasing flue gas temperature along the furnace height and the aerodynamic field characteristics of the gradually increasing hot tangent circle diameter of the furnace cross-section, creates a beneficial compensation and dynamic balance, which helps prevent slagging in the furnace.

[0039] Part of the secondary air is fed into the furnace tangentially through intermediate layer burners arranged on the four walls of the furnace. This timely and appropriate oxygen supplementation in the pulverized coal combustion reduction zone enhances the swirl intensity of the rising flue gas, increases the residence time of pulverized coal, and promotes early and complete combustion. Simultaneously, the intermediate layer burners have a relatively low design airflow, so they will not significantly negatively impact the NOx reduction process. The remaining secondary air is fed into the furnace tangentially in the reverse direction through rectifier burners arranged on the four walls of the furnace, i.e., the imaginary tangent circle is counterclockwise.

[0040] The rectifier burner is located in the final stage of the pulverized coal combustion process, and its large air volume ensures complete combustion of the pulverized coal. The wall-mounted arrangement reduces the distance between the reverse airflow and the main airflow, thereby shortening the mixing delay time and reducing the degree of energy attenuation due to the reverse airflow. Furthermore, the large momentum of its reverse airflow is very effective in eliminating residual rotation of the flue gas at the furnace outlet, thus allowing for excellent control of the flue gas temperature deviation and steam temperature deviation at the furnace outlet.

[0041] The four sets of burners described above have different functions, and their hypothetical tangential diameters or directions are designed with different parameters according to functional requirements, thus forming a three-dimensional composite tangential combustion system within the boiler. Through this combustion system design, the furnace space is optimized. With the same furnace dimensions, the combustion center shifts downward, increasing the actual combustion stroke of pulverized coal and correspondingly reducing the height distance required for complete pulverized coal combustion, thereby lowering the flue gas temperature at the furnace outlet. The actual heat load level within the furnace is balanced in both the furnace height and planar direction, achieving optimal equilibrium throughout the pulverized coal combustion process. This improves the flue gas temperature field distribution and significantly enhances the boiler's adaptability to strongly slagging coal types, achieving the goal of full-load combustion of all strongly slagging coal types.

[0042] Example 2

[0043] refer to Figures 1-9 The difference from Example 1 is that the main burner group includes a lower main burner group, a middle main burner group, and an upper main burner group arranged in the height direction of the furnace.

[0044] In this embodiment, the main burner group is respectively configured with multiple layers of pulverized coal nozzles 2, 5, and 12 and corresponding secondary air nozzles 1, 4, and 12. The distance between the lowest pulverized coal nozzle 2 of the lower main burner group and the highest pulverized coal nozzle 13 of the upper main burner group is H. The spacing between adjacent pulverized coal nozzles 2 in the lower main burner group is H1. The distance between adjacent pulverized coal nozzles 5 in the middle main burner group is H3. The distance between adjacent pulverized coal nozzles 13 in the upper main burner group is H5. H1 < H3 < H5, and 0 < (H3 - H1) ≤ 550 mm, 0 < (H5 - H3) ≤ 500 mm. The distance between the upper pulverized coal nozzle 2 and the lowermost pulverized coal nozzle 5 of the middle main burner is H2, where 2.5m ≤ H2 ≤ 6m; the distance between the uppermost pulverized coal nozzle 5 of the middle main burner and the lowermost pulverized coal nozzle 13 of the upper main burner is H4, where 2.5m ≤ H4 ≤ 6m; and 0 ≤ (H4 - H2) ≤ 500mm; the distance between the middle burner and the uppermost pulverized coal nozzle 13 of the upper main burner is H6, and the distance between the rectifier burner and the middle burner is H7. In the lower burner group, the centerline of the pulverized coal nozzle 2 is aligned with the centerline of the main burner group air box 3 outlet, forming an angle α with the diagonal of the boiler body 11 cross-section. In the middle burner group, the centerline of the pulverized coal nozzle 5 is aligned with the centerline of the main burner group air box 6 outlet, forming an angle β with the diagonal of the boiler body 11 cross-section. The range of α is 0°-4°, and the range of β is 0°-3°, with 1°≤(α-β)≤4°. In the lower burner group, the airflow direction at the outlet of the secondary air nozzle 1 forms an angle θ with the centerline of the pulverized coal nozzle 2, with θ ranging from 0° to 20°. In the middle burner, the outlet airflow direction of the secondary air nozzle 5 forms an angle λ with the centerline of the pulverized coal nozzle 4, where λ ranges from 0° to 20°; in the lower burner, the outlet airflow direction of the secondary air nozzle 12 forms an angle τ with the centerline of the pulverized coal nozzle 13, where τ ranges from 0° to 20°; in the upper burner, the centerline of the pulverized coal nozzle 13 is aligned with the outlet centerline of the main burner group air box 14, and forms an angle ω with the diagonal of the boiler body 11 cross-section, where ω ranges from 0° to 2°, and 1°≤(α-β)≤4°, 1°≤(β-ω)≤3°.

[0045] With the main burner group divided into three sets, each burner has a smaller height-to-width ratio, which further improves the gas supply conditions on both sides of the burner outlet airflow. This results in higher airflow rigidity and greater stability of the combustion fireball, allowing for better control of excessive flame deflection. This design also enables lower near-water-cooled wall flue gas temperatures, providing superior protection against slagging on the water-cooled walls in the burner area. Furthermore, at the same design height H, the spacing between the two layers of pulverized coal nozzles in each main burner group is relatively smaller, leading to stronger mutual support between adjacent flames.

[0046] Example 3

[0047] This invention also discloses a pulverized coal boiler equipped with a three-dimensional composite tangential combustion system.

[0048] In the description of this invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0049] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw-in," "pad," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] The foregoing description illustrates and describes preferred embodiments of the present invention. As previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A three-dimensional composite tangential combustion system suitable for pulverized coal boilers burning strongly slagging coal, arranged on the boiler body, wherein the boiler body has a width dimension W and a depth dimension D, characterized in that, include: At least two main burner groups are arranged vertically along the height of the furnace, located at the corner of the lower part of the furnace, forming a clockwise rotating tangential combustion. The intermediate layer burner is arranged on the four walls of the boiler body above the main burner group, including combustion-promoting nozzles and intermediate air boxes. Its outlet airflow direction forms an angle with the boiler wall surface, forming an imaginary tangent circle that rotates clockwise. A rectifier burner is arranged on the four walls of the boiler body above the intermediate layer burner. It includes a rectifier nozzle and a rectifier air box. Its outlet airflow direction is towards the center of the furnace, forming an imaginary tangent circle that rotates counterclockwise. The reverse airflow of the rectifier burner is used to counteract the clockwise rotating airflow generated by the main burner and the intermediate layer burner.

2. The three-dimensional composite tangential combustion system for pulverized coal boilers burning strongly slagging coal as described in claim 1, characterized in that: One arrangement of the main burner group includes a lower main burner group and an upper main burner group arranged in the height direction of the furnace, and the main burner group is respectively equipped with multiple layers of pulverized coal nozzles and corresponding secondary air nozzles.

3. The three-dimensional composite tangential combustion system for pulverized coal boilers burning strongly slagging coal as described in claim 1, characterized in that: Another arrangement of the main burner group includes a lower main burner group, a middle main burner group, and an upper main burner group arranged in the height direction of the furnace. The main burner group is equipped with multiple layers of pulverized coal nozzles and corresponding secondary air nozzles.

4. The three-dimensional composite tangential combustion system for pulverized coal boilers burning strongly slagging coal as described in claim 2, characterized in that: In the lower main burner group, the distances between adjacent pulverized coal nozzles from bottom to top are H1 and H2, respectively, where 0 ≤ (H2-H1) ≤ 450 mm; the distance between the uppermost pulverized coal nozzle in the lower main burner group and the lowermost pulverized coal nozzle in the upper main burner group is H3, where 2.5 m ≤ H3 ≤ 6 m; in the upper main burner group, the distances between adjacent pulverized coal nozzles from bottom to top are H4 and H5, respectively, where 0 ≤ (H5-H4) ≤ 400 mm; the distance between the intermediate burner group and the uppermost pulverized coal nozzle in the upper main burner group is H6, where 2 m ≤ H6 ≤ 10 m; the distance between the rectifier burner and the intermediate burner group is H7, where 3 m ≤ H7 ≤ 12 m; and H1 ≤ H2 < H4 ≤ H5, where 0 < (H4-H2) ≤ 500 mm.

5. The three-dimensional composite tangential combustion system for pulverized coal boilers burning strongly slagging coal as described in claim 3, characterized in that: The distance between the lowest pulverized coal nozzle of the lower main burner group and the highest pulverized coal nozzle of the upper main burner group is H; the spacing between adjacent pulverized coal nozzles in the lower main burner group is H1; the distance between adjacent pulverized coal nozzles in the middle main burner group is H3; and the distance between adjacent pulverized coal nozzles in the upper main burner group is H5, where H1 < H3 < H5, and 0 < (H3 - H1) ≤ 550 mm, 0 < (H5 - H3) ≤ 500 mm; the lower main burner group... The distance between the uppermost pulverized coal nozzle of the burner and the lowermost pulverized coal nozzle of the middle main burner is H2, where 2.5m ≤ H2 ≤ 6m; the distance between the uppermost pulverized coal nozzle of the middle main burner and the lowermost pulverized coal nozzle of the upper main burner is H4, where 2.5m ≤ H4 ≤ 6m; and 0 ≤ (H4 - H2) ≤ 500mm; the distance between the middle burner and the uppermost pulverized coal nozzle of the upper main burner is H6, and the distance between the rectifier burner and the middle burner is H7.

6. The three-dimensional composite tangential combustion system for pulverized coal boilers burning strongly slagging coal as described in claim 4, characterized in that: The centerline of the pulverized coal nozzle in the lower burner is aligned with the centerline of the main burner group's air box outlet, forming an angle α with the diagonal of the boiler body cross-section. The centerline of the pulverized coal nozzle in the upper burner is aligned with the centerline of the main burner group's air box outlet, forming an angle β with the diagonal of the boiler body cross-section. The range of α is 0°-4°, and the range of β is 0°-3°, with 1°≤(α-β)≤4°. The airflow direction at the outlet of the secondary air nozzle in the lower burner forms an angle θ with the centerline of the pulverized coal nozzle, with the range of θ being 0°-20°. The airflow direction at the outlet of the secondary air nozzle in the upper burner forms an angle λ with the centerline of the pulverized coal nozzle, with the range of λ being 0°-20°. The centerline of the outlet of the intermediate air box in the intermediate layer burner is aligned with the centerline of the outlet of the combustion-promoting nozzle, forming an angle ρ with the boiler body wall, with 45°≤ρ≤135°.

7. The three-dimensional composite tangential combustion system for pulverized coal boilers burning strongly slagging coal as described in claim 5, characterized in that: The centerline of the pulverized coal nozzle in the lower burner group is aligned with the centerline of the main burner group's air box outlet, forming an angle α with the diagonal of the boiler body cross-section. Similarly, the centerline of the pulverized coal nozzle in the middle burner group is aligned with the centerline of the main burner group's air box outlet, forming an angle β with the diagonal of the boiler body cross-section. The range of α is 0°-4°, and the range of β is 0°-3°, with 1°≤(α-β)≤4°. The airflow direction at the outlet of the secondary air nozzle in the lower burner group forms an angle θ with the centerline of the pulverized coal nozzle, with θ ranging from 0° to 2°. 0°; the airflow direction at the outlet of the secondary air nozzle in the middle burner forms an angle λ with the centerline of the pulverized coal nozzle, and the range of λ is 0°-20°; the airflow direction at the outlet of the secondary air nozzle in the lower burner forms an angle τ with the centerline of the pulverized coal nozzle, and the range of τ is 0°-20°; the centerline of the pulverized coal nozzle in the upper burner is consistent with the centerline of the air box outlet of the main burner group, and forms an angle ω with the diagonal of the boiler body section, and the range of ω is 0°-2°, and 1°≤(α-β)≤4°, 1°≤(β-ω)≤3°.

8. The three-dimensional composite tangential combustion system for pulverized coal boilers burning strongly slagging coal, as described in claim 6 or 7, is characterized in that: The distance from the intermediate layer burner positioning point to the adjacent wall of the boiler body is L1, 1.5m≤L1≤W / 3, and the distance from the rectifier burner positioning point to the center line of the boiler body section is L2, W / 8≤L2≤W / 4.

9. The three-dimensional composite tangential combustion system for pulverized coal boilers burning strongly slagging coal, as described in claim 6 or 7, is characterized in that: The center line of the intermediate air box outlet of the intermediate layer burner is aligned with the center line of the combustion-promoting nozzle outlet, and the angle between the intermediate air box outlet and the boiler body wall is ρ, where 45°≤ρ≤135°.

10. A pulverized coal boiler, characterized in that... It is equipped with a three-dimensional composite tangential combustion system as described in any one of claims 1 to 9.

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