Heat exchanger staggered row spacing increasing tube bundle structure for boiler ash removal

Abstract

The invention relates to the technical field of boiler tube bundle ash removal, in particular to a heat exchanger staggered progressive increase row spacing tube bundle structure for boiler ash removal, which comprises an ash removal device and a plurality of heat exchange tube bundles mounted on a boiler, the ash removal device is used for cleaning accumulated ash on the heat exchange tube bundles, and the heat exchange tube bundles are distributed in a staggered manner. The multiple rows of heat exchange tube bundles are arranged in parallel, and the column intervals between the heat exchange tube bundles in the same row are gradually increased in the flue gas flowing direction. According to the heat exchanger tube bundle structure with the staggered row spacing increasing row spacing for boiler ash removal, high-pressure ash removal water flow can preferentially impact the front tube bundle to form high-speed flow concentrated distribution, the ash particle stripping effect is enhanced, meanwhile, more heat exchange tubes are covered, the ash removal efficiency is remarkably improved, and the service life of the heat exchanger is prolonged. And on the premise that the number of the heat exchange tubes which are uniformly arranged is the same, efficient ash removal and stable heat exchange are both considered.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of boiler tube bundle soot blowing, in particular to a heat exchanger staggered arrangement incremental column spacing tube bundle structure for boiler soot blowing. BACKGROUND

[0002] The boiler tube bundle is the core component of boiler heat exchange, which mainly functions to absorb the convective heat of flue gas and ensure the evaporation capacity of the boiler. During long-term operation of the boiler, the products of fuel combustion (such as fly ash and coking) and the corrosion products of flue gas will adhere to the tube bundle to form soot, which will significantly reduce the heat transfer efficiency, increase the flue gas resistance, and even cause local overheating or tube bundle corrosion. Therefore, regular soot blowing is a key link to ensure the safe and economic operation of the boiler.

[0003] In the prior art, the commonly used soot blowing methods are mechanical vibration soot blowing, manual soot blowing and high-pressure water jet soot blowing. The high-pressure water jet soot blowing is more thorough, can remove hard scale and coking, and has less damage to the tube bundle. However, the conventional tube bundle is arranged uniformly, which causes the kinetic energy of the soot blowing water flow to be significantly attenuated after passing through the front tube bundle, and the soot blowing effect of the rear tube bundle is poor. Especially when small-diameter nozzles are used, the water flow has limited coverage, making it difficult to effectively clean the soot on the surface of the entire tube bundle, which affects the heat exchange efficiency. Moreover, since the front tube bundle directly contacts the high-speed flue gas, the soot accumulation rate is much higher than that of the rear tube bundle. The uniform arrangement of the tube bundle cannot concentrate the soot blowing water flow on the front tube bundle area with severe soot accumulation, resulting in uneven soot blowing effect.

[0004] Therefore, there is an urgent need for a tube bundle arrangement structure for the boiler, which can make the high-pressure soot blowing water flow preferentially impact the front tube bundle to form a concentrated distribution of high-speed flow, enhance the soot particle stripping effect, cover more heat exchange tubes, and significantly improve the soot blowing efficiency. Under the premise of maintaining the same number of heat exchange tubes as the uniform arrangement, both efficient soot blowing and stable heat exchange are considered. SUMMARY

[0005] The present application aims to provide a heat exchanger staggered arrangement incremental column spacing tube bundle structure for boiler soot blowing, so that the high-pressure soot blowing water flow preferentially impacts the front tube bundle to form a concentrated distribution of high-speed flow, enhances the soot particle stripping effect, covers more heat exchange tubes, and significantly improves the soot blowing efficiency. Under the premise of maintaining the same number of heat exchange tubes as the uniform arrangement, both efficient soot blowing and stable heat exchange are considered.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solution: a heat exchanger staggered arrangement incremental column spacing tube bundle structure for boiler soot blowing, comprising a soot blowing device and a heat exchange tube bundle installed on the boiler. The soot blowing device is used to clean the soot on the heat exchange tube bundle. The heat exchange tube bundle is arranged in multiple rows in a staggered arrangement. The multiple rows of heat exchange tube bundles are arranged in parallel to each other. The column spacing between the heat exchange tube bundles in the same row increases along the flue gas flow direction.

[0007] The beneficial effects of the scheme are: through the synergistic effect of staggered arrangement and increasing row spacing, the problem of uneven dust removal of heat exchange tube bundle is effectively solved, the staggered arrangement makes the dust removal water flow produce turbulent disturbance between the heat exchange tube bundles, the dust removal water flow is fully diffused and energy exchanged, and the peeling effect of the dust particles is enhanced; the increasing row spacing makes the water flow preferentially impact the front tube bundle area with serious dust accumulation, while ensuring the coverage range of the rear tube bundle. Compared with the existing uniform arrangement structure, the design makes the water flow kinetic energy distribution more reasonable, under the premise of maintaining the same heat exchange area, the dust removal efficiency of the serious dust accumulation area is improved, the overall dust removal effect is ensured, and the problem of heat transfer efficiency reduction caused by dust accumulation is effectively solved.

[0008] Further, the row spacing of the multiple rows of heat exchange tube bundles is the same, and the row spacing is 100mm-200mm.

[0009] Further, the increasing row spacing is linear or nonlinear.

[0010] Further, the row spacing is nonlinearly increased in a quadratic arithmetic sequence, and the general term formula is: .

[0011] Further, the dust removal device comprises a nozzle, a water supply pipe and a valve, the water supply pipe is used to provide the dust removal water flow for dust removal of the heat exchange tube bundle, the valve is used to control the dust removal water flow in the water supply pipe to be sprayed out of the nozzle, and the pressure of the dust removal water flow sprayed out of the nozzle is not less than 0.3Mpa.

[0012] Further, the nozzle is connected to one end of the heat exchange tube bundle with the smallest row spacing, and the nozzle is perpendicular to the axial direction of the heat exchange tube bundle.

[0013] Further, the outlet of the nozzle is not less than twice the pipe diameter away from the nearest heat exchange tube bundle.

[0014] Further, the number of rows of the heat exchange tube bundle is an odd number, and the outlet of the nozzle is directly opposite to the heat exchange tube bundle located in the middle of the odd number of rows.

[0015] Further, the pipe diameter of the heat exchange tube bundle is 10mm-200mm. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the application; Figure 2 It is a longitudinal sectional flow field velocity distribution schematic diagram of the application; The following will be further described in detail through specific embodiments: The reference signs in the drawings of the specification include: heat exchange tube bundle 1, water supply pipe 2, valve 3, nozzle 4. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application.

[0018] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0019] The embodiments are substantially as shown in the accompanying drawings Figures 1-2 as shown in the accompanying drawings Figure 1 A heat exchanger staggered incremental column spacing tube bundle structure for boiler ash removal, comprising an ash removal device and a heat exchange tube bundle 1 installed on the boiler, the ash removal device is used for cleaning the ash on the heat exchange tube bundle 1, the heat exchange tube bundle 1 is multiple and arranged in staggered arrangement, the multiple rows of heat exchange tube bundles 1 are arranged in parallel with each other, and the column spacing between the heat exchange tube bundles 1 in the same row increases along the smoke flow direction; the staggered arrangement is that the heat exchange tube bundle 1 is divided into multiple rows, and the heat exchange tube bundles 1 in adjacent rows are staggered (rather than aligned), that is, the projection of any row of heat exchange tube bundles 1 can fall in the gap of the heat exchange tube bundles 1 in the adjacent row, the staggered arrangement makes the smoke flow around each heat exchange tube bundle 1, forming strong turbulence, greatly improving the heat transfer efficiency, and at the same time, the turbulence is used to wash the pipe wall of the heat exchange tube bundle 1 to reduce the ash; the column spacing increases in two ways of linear increase and nonlinear increase, wherein the linear increase can be realized by fixed increment, and the nonlinear increase can adopt logarithmic increase or exponential increase mode. As a preferred embodiment, the minimum column spacing can be set to 1.5 times the diameter of the heat exchange tube bundle 1, and the column spacing change rate can be adjusted according to the ash concentration gradient of the flue gas, and a smaller initial spacing is set in the serious ash deposition area; in this application, the column spacing refers to the axial spacing between the heat exchange tube bundles 1 in the same row and adjacent to each other.

[0020] Through the synergistic effect of staggered arrangement and incremental column spacing, the problem of uneven ash removal of the heat exchange tube bundle 1 is effectively solved, the staggered arrangement makes the ash removal water flow produce turbulent disturbance between the heat exchange tube bundles 1, the ash removal water flow is fully diffused and energy exchanged, and the peeling effect of the ash particles is enhanced; the incremental column spacing makes the water flow preferentially impact the serious ash deposition area of the front tube bundle, while ensuring the coverage range of the rear tube bundle. Compared with the existing uniform arrangement structure, the design makes the water flow kinetic energy distribution more reasonable, under the premise of maintaining the same heat exchange area, the ash removal efficiency of the serious ash deposition area is improved, and the overall ash removal effect is ensured, effectively solving the problem of heat transfer efficiency reduction caused by ash deposition.

[0021] In the embodiment, the row spacing of the plurality of rows of heat exchange tube bundles 1 is the same, and the row spacing is 100mm-200mm; the same arrangement of the row spacing ensures the uniformity of the water flow coverage of the ash removal device, and avoids the problem of uneven water flow distribution caused by different row spacings. As a preferred embodiment, the row spacing can be set to 150mm, which is the middle value in the range, and can balance the water flow impact force and coverage range. In addition, the limitation of the row spacing can be realized by the positioning hole of the heat exchange tube bundle 1 support frame, for example, equidistantly arranged mounting hole positions, or through the standardized design of the tube bundle connecting piece, for example, connecting rod pieces of uniform length to fix adjacent tube rows; in the present application, the row spacing refers to the axial spacing between the heat exchange tube bundles 1 of adjacent rows and located in the same column.

[0022] The technical scheme limits the row spacing range, solves the problem of too fast energy attenuation of the ash removal water flow in the traditional uniform arrangement of tube bundles. When the row spacing is too small, the water flow interference between adjacent tube rows increases, resulting in insufficient impact force of the rear tube row; when the row spacing is too large, the kinetic energy loss of the water flow between the tube rows is too large, and the effective ash removal pressure cannot be maintained. By limiting the row spacing range, the ash peeling effect of the front tube row can be ensured, and the rear tube row can also obtain sufficient impact force. Compared with the completely uniform tube bundle arrangement in the prior art, the present scheme optimizes the row spacing parameter, so that the energy distribution of the ash removal water flow is more in line with the ash distribution law of the tube bundle, and the overall ash removal efficiency is improved.

[0023] In the embodiment, the increment of the column spacing is linear or nonlinear; linear increment means that the difference value of the column spacing of the heat exchange tube bundles 1 in the same row and adjacent to each other remains constant, which is equivalent to forming an arithmetic sequence; nonlinear increment includes but is not limited to the following implementation modes: adopting a quadratic function increasing mode, so that the column spacing change rate gradually increases along the direction of the flue gas flow; adopting a segmented linear increasing mode, setting different incremental gradients in different tube bundle regions; adopting an exponential increasing mode, so that the column spacing change in the front tube bundle region is more significant; the type of column spacing increment can be selected according to the actually detected ash thickness distribution, which is not limited here.

[0024] The technical scheme provides two differentiated column spacing adjustment modes, effectively solving the problem of non-ideal ash removal water flow distribution caused by the traditional uniform column spacing arrangement. The linearly increasing mode uniformly attenuates water flow energy, is suitable for working conditions with uniform ash deposition distribution, and can ensure full-range effective coverage of the ash removal water flow. The non-linearly increasing mode can maintain water flow impact force by non-linearly increasing the column spacing for the front heat exchange tube bundle 1 area with severe ash deposition, and can also ensure the optimized distribution of the water flow in the rear heat exchange tube bundle 1 area with less ash deposition. Compared with the prior art, the limitations of single column spacing arrangement are improved, the dynamic matching relationship between the column spacing and the ash deposition distribution is established, the optimized distribution of the ash removal energy on the tube bundle surface is realized, and the overall ash removal efficiency is significantly improved. As a preferred embodiment, the column spacing is non-linearly increased in a quadratic arithmetic sequence, and the general term formula is: wherein, represents the nth column spacing.

[0025] In this embodiment, the ash removal device includes a nozzle 4, a water supply pipe 2, and a valve 3. The water supply pipe 2 is used to provide ash removal water flow for the heat exchange tube bundle 1, and the valve 3 is used to control the ash removal water flow in the water supply pipe 2 to be sprayed from the nozzle 4. The pressure of the ash removal water flow at the nozzle 4 is not less than 0.3 MPa. The nozzle 4 can be a fan-shaped nozzle 4 or a conical nozzle 4. The fan-shaped nozzle 4 can form a flat water curtain to expand the coverage range, and the conical nozzle 4 can form a concentrated jet to enhance the impact force. The water supply pipe 2 can be a stainless steel pipe or a high-pressure rubber pipe. The inner diameter of the water supply pipe 2 can be selected according to the actual required flow and water pressure of the ash removal water flow to ensure sufficient flow supply and constant ash removal water flow pressure. The valve 3 can be a manual valve 3, an electric ball valve, or a pneumatic butterfly valve. As a preferred embodiment, the valve 3 can be automatically opened and closed in linkage with the operation state of the boiler through a PLC control system. A pressure sensor can be integrated at the inlet of the nozzle 4 to monitor the spraying pressure in real time and feed back to the control system. When the pressure is lower than 0.3 MPa, an alarm is automatically triggered to remind the site staff. As a preferred embodiment, the installation angle of the nozzle 4 can be set to a 15°-30° adjustable structure to meet the cleaning needs of different heat exchange tube bundle 1 spacings.

[0026] By establishing a pressure-controllable fluid power system, the valve 3 is used to accurately adjust the water flow parameters, and the high-pressure nozzle 4 is used to form a directional jet. Among them, the minimum pressure standard of 0.3Mpa is the critical value verified by fluid mechanics experiment, which can ensure that the water flow has enough kinetic energy to penetrate the ash layer and strip the pipe wall deposits. Compared with the traditional low-pressure cleaning system, the scheme realizes the quantitative guarantee of the cleaning effect through pressure closed-loop control, solves the problem of incomplete cleaning caused by pressure fluctuation. The cooperation of the water supply pipeline and the control valve 3 makes the system can quickly respond to the cleaning demand, complete efficient cleaning in the operation gap of the boiler, and avoid the loss of production caused by cleaning during shutdown. The special structure design of the nozzle 4 makes the water flow form the best diffusion form while maintaining high pressure, which not only ensures the single-point impact force but also takes into account the coverage range, significantly improving the cleaning uniformity of the staggered tube bundle.

[0027] In this embodiment, the nozzle 4 is connected to one end of the minimum pitch of the heat exchange tube bundle 1, and the nozzle 4 is perpendicular to the axial direction of the heat exchange tube bundle 1. The arrangement position of the nozzle 4 is limited to the minimum pitch end of the heat exchange tube bundle 1, which refers to the front end area in the direction of the flue gas flow. As a preferred embodiment, the nozzle 4 can be fixed at the end of the water supply pipe 2 by flange connection or threaded connection, and the installation height is flush with the center line of the minimum pitch tube bundle. The nozzle 4 is perpendicular to the axial direction of the heat exchange tube bundle 1, which can ensure that the initial direction of the cleaning water flow sprayed by the nozzle 4 is perpendicular to the heat exchange tube bundle 1, so that the cleaning water flow does not deviate too much when it first contacts the heat exchange tube bundle 1, and the contact area between the cleaning water flow and the heat exchange tube bundle 1 is larger. The cleaning effect of the heavily soiled front tube bundle area is improved, and the cleaning efficiency is improved. In addition, the diameter of the nozzle 4 can be preferably 2mm-5mm to form a dense water flow with sufficient kinetic energy under 0.3MPa pressure.

[0028] The working principle of the technical scheme is that the minimum pitch area has the highest flue gas flow rate and the fastest soiling rate, and by arranging the nozzle 4 directly in this area, the high-pressure water flow can act on the most heavily soiled tube bundle surface. At the same time, the vertical injection design minimizes the kinetic energy loss of the water flow. Compared with oblique injection, the impact force is improved, which can effectively destroy the adhesion between the ash layer and the pipe wall, and solve the technical problem of insufficient cleaning in the high-soiling area when the nozzle 4 is uniformly arranged.

[0029] In this embodiment, the outlet of the nozzle 4 is at a distance of not less than twice the diameter of the heat exchange tube bundle 1 from the nearest heat exchange tube bundle 1; the distance parameter limit can be used to fix the position of the nozzle 4 by using the adjustable support of the prior art, and the distance adjustment can be realized by a threaded mechanism or a hydraulic push rod, or a positioning reference can be set in advance during the installation stage of the tube bundle to ensure that the installation position of the nozzle 4 meets the minimum distance requirement; by establishing the minimum distance standard between the nozzle 4 and the tube bundle, the cleaning water flow can be fully diffused before contacting the tube bundle. The distance limit of twice the tube diameter not only ensures the coverage area of the water flow, but also reduces the impact pressure through the natural diffusion of the fluid, effectively avoiding the deformation of the tube wall while removing the hard scale on the surface of the tube bundle. Compared with the prior art scheme of arbitrarily setting the distance of the nozzle 4, this parameterized design significantly improves the reliability and adaptability of the cleaning system, and is especially suitable for heat exchange tube bundle 1 arrays of different tube diameter specifications.

[0030] In this embodiment, the number of rows of the heat exchange tube bundle 1 is an odd number, and the outlet of the nozzle 4 is directly opposite the heat exchange tube bundle 1 located in the middle of the odd number of rows; specifically, the odd number of rows can be arranged in the form of 3 rows, 5 rows, or 7 rows, etc., and the 5-row arrangement is a more preferred embodiment, and when the nozzle 4 is aligned with the middle row of tube bundles, the installation position deviation should be controlled within ±5mm. As a preferred embodiment, when 5 rows of tube bundles are used, the center line of the nozzle 4 should coincide with the center axis of the third row of tube bundles. In the implementation process, the spray angle of the nozzle 4 can be set to vertical spraying or have an adjustable range of ±10° to adapt to different tube bundle spacing requirements.

[0031] Through the synergistic effect of odd-numbered row symmetric arrangement and central positioning of the nozzle 4, the cleaning water flow forms a relatively symmetrical distribution between the tube bundles, wherein the odd-numbered row structure forms a mirror-symmetrical flow channel in the direction of the flue gas flow, and the nozzle 4 aligned with the middle row of tube bundles can maximize the uniform distribution of the cleaning water flow in the radial direction. Avoiding the problem that the cleaning water flow is either applied to the heat exchange tube bundle 1 near the middle to make the cleaning water flow distribution deviate from uniformity or directly sprayed in the middle to directly contact the heat exchange tube bundle 1 before the spray section. The symmetrical impact mode generated thereby can prevent excessive deflection when the cleaning water flow acts on the most severely soiled tube bundle surface, so that each row of tube bundles obtains balanced cleaning effect, significantly improves the uniformity of water flow coverage, and under the same water pressure conditions, can reduce the cleaning blind area, and at the same time, reduces the risk of local tube bundle wear caused by uneven water flow impact.

[0032] In this embodiment, the heat exchange tube bundle 1 has a tube diameter of 10mm-200mm. The lower limit of 10mm is based on the following considerations: when the tube diameter is less than 10mm, the tube wall structure is insufficient in strength, and is prone to deformation or rupture when subjected to high-pressure water jet impact of not less than 0.3MPa; at the same time, too small tube diameter will result in insufficient water flow passage cross-sectional area, and the resistance of the cleaning water flow will increase significantly, affecting the jet velocity and coverage. The upper limit of 200mm is based on the following considerations: when the tube diameter exceeds 200mm, the heat exchange surface area per unit length of the tube bundle decreases significantly, and it is difficult to meet the heat exchange efficiency requirement; and too large tube diameter will result in too large distance between the nozzle 4 and the surface of the heat exchange tube bundle 1 (which needs to be kept not less than twice the tube diameter), which will cause serious diffusion of the cleaning water flow and rapid decay of the impact force. As a preferred embodiment, the tube diameter can be selected as typical values such as 25mm, 50mm, 100mm, etc.

[0033] By limiting the tube diameter range of the heat exchange tube bundle 1, the synergistic optimization of the cleaning effect and the heat exchange efficiency is achieved. The lower limit value ensures the structural reliability of the tube bundle under high-pressure cleaning conditions and maintains sufficient water flow passability; the upper limit value guarantees the necessary heat exchange surface area while avoiding excessive diffusion of the cleaning water flow. This design parameter is technically synergistic with the cleaning pressure (≥0.3MPa) and the nozzle 4 arrangement distance (≥2 times the tube diameter), so that the high-pressure water flow can effectively cover the surface of the tube bundle, while not negatively affecting the heat exchange performance.

[0034] As shown in Figure 2 Performance analysis of the heat exchanger staggered incremental column spacing tube bundle structure is carried out by using the computational fluid dynamics simulation software FLUENT, and comparison is made with the existing uniform column spacing tube bundle structure. Figure 2 is a longitudinal cross-sectional flow field velocity distribution diagram, and the left side Velocity Magnitude (velocity size) indicates the velocity value of fluid motion, i.e. the velocity size of the cleaning water flow in this application, wherein Figure 2 (a) is the column spacing incremental (linearly incremental or non-linearly incremental) arrangement of this application, Figure 2 (b) is the uniform arrangement, Figure 2 (c) is the column spacing decreasing arrangement.

[0035] It can be seen from the comparison that the column spacing distribution of the heat exchange tube bundle 1 has a significant impact on the diffusion behavior of the cleaning water flow. In the uniform column spacing distribution and the gradually decreasing column spacing arrangement, due to the excessive column spacing of the first two rows of heat exchange tube bundles 1, most of the cleaning water flow can only flow through the first column of heat exchange tube bundles 1, and cannot effectively diffuse to the subsequent heat exchange tube bundle 1 area. This phenomenon causes the momentum of the cleaning water flow to be largely lost near the heat exchange tube bundle 1 close to the nozzle 4, and cannot provide sufficient cleaning power for the subsequent heat exchange tube bundle 1. When the staggered arrangement with increasing column spacing is used, due to the optimized design of the column spacing of the first two rows of heat exchange tube bundles 1, the column spacing is relatively small, so that the water flow can fully diffuse and exchange energy near the heat exchange tube bundle 1 close to the nozzle 4. This arrangement ensures that the cleaning water flow can effectively cover the downstream tube bundle area. The numerical simulation results show that this gradually increasing spacing arrangement can maintain the high-speed area of the water flow to extend continuously downstream, providing uniform cleaning effect for the entire tube bundle area. This flow field characteristic significantly improves the energy utilization rate of the cleaning water flow, thereby achieving better cleaning performance.

[0036] The above is only an embodiment of the present application, and common technical solutions and / or characteristics in the scheme are not described in detail. It should be noted that for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, and these will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific embodiments and the like in the specification can be used to explain the content of the claims.

Claims

1. A heat exchanger staggered incremental row spacing tube bundle structure for boiler ash cleaning, characterized by: The ash cleaning device is used for cleaning the ash on the heat exchange tube bundle, and the heat exchange tube bundle is multiple and arranged in staggered rows.

2. A heat exchanger staggered incremental row pitch tube bundle structure for boiler ash removal according to claim 1, characterized in that: The row spacing of the multiple rows of heat exchange tube bundles is the same, and the row spacing is 100mm-200mm.

3. A heat exchanger staggered incremental row pitch tube bundle structure for boiler ash removal according to claim 1, characterized in that: The increment of the column spacing is linear or nonlinear.

4. A heat exchanger staggered incremental row pitch tube bundle structure for boiler ash removal according to claim 3, characterized in that: The column spacing is nonlinearly increased in a second-order arithmetic sequence, and the general term formula is: .

5. A heat exchanger staggered incremental row pitch tube bundle structure for boiler ash removal according to claim 1, characterized in that: The ash cleaning device comprises a nozzle, a water supply pipe and a valve.

6. A heat exchanger staggered incremental row pitch tube bundle structure for boiler ash removal according to claim 5, characterized in that: The nozzle is connected to one end of the heat exchange tube bundle with the smallest column spacing, and the nozzle is perpendicular to the axial direction of the heat exchange tube bundle.

7. A heat exchanger staggered incremental row pitch tube bundle structure for boiler ash removal according to claim 5, characterized in that: The outlet of the nozzle is not less than twice the diameter of the heat exchange tube bundle away from the nearest heat exchange tube bundle.

8. A heat exchanger staggered incremental row pitch tube bundle structure for boiler ash removal according to claim 5, characterized in that: The number of rows of the heat exchange tube bundle is odd, and the outlet of the nozzle is right opposite to the heat exchange tube bundle in the middle of the odd rows.

9. A heat exchanger staggered incremental row pitch tube bundle structure for boiler ash removal according to claim 7, characterized in that: The diameter of the heat exchange tube bundle is 10mm-200mm.

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