Waste heat boiler

Abstract

The utility model relates to a waste heat boiler, and relates to the technical field of waste heat recovery, the waste heat boiler comprises a boiler barrel and a flue gas radiation box, the flue gas radiation box is provided with an inlet flue, an outlet flue and a membrane type water cooling wall, and the boiler barrel communicates with the membrane type water cooling wall through a downcomer and is used for providing water for the membrane type water cooling wall; the flue gas radiation box is communicated with the boiler barrel through an ascending pipe and is used for introducing a steam-water mixture generated by water heated by flue gas at high temperature in the membrane water cooling wall into the boiler barrel; a flue gas staying piece is further arranged in the flue gas radiation box and used for prolonging the staying time of flue gas in the flue gas radiation box so as to prolong the heat exchange time. Compared with the prior art, the waste heat boiler is better in sealing performance through the arrangement of the membrane type water cooling wall, the problem of high-temperature flue gas leakage can be solved, the manufacturing period can be shortened, and the boiler manufacturing cost can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of waste heat recovery, and in particular to a waste heat boiler. Background Art

[0002] Industrial production often produces some high-temperature, normal-pressure flue gases, which have the characteristics of small flow, complex composition, strong corrosiveness, high dust content, and low ash melting point. Such flue gases need to be cooled and harmlessly treated. If the waste heat is not recovered during the treatment process and water is directly sprayed for cooling, a large amount of water and electricity resources will be consumed.

[0003] Waste heat utilization generally uses waste heat boilers to generate steam. There are two types of waste heat boilers: fire tube waste heat boilers and water tube waste heat boilers. Due to the high dust content and low ash melting point of flue gas, if a fire tube waste heat boiler is used for waste heat recovery, the heat exchange tube will be clogged by ash accumulation during operation and it is difficult to clean. This type of furnace is not suitable for waste heat recovery of this type of flue gas. Therefore, a water tube waste heat boiler is more suitable for waste heat recovery of this type of flue gas. However, the following problems still need to be solved when using a water tube waste heat boiler: 1. The waste heat recovery efficiency is low, and the flue gas stays in the boiler for a short time and cannot effectively exchange heat, resulting in poor heat exchange effect and large heat loss in the flue gas; 2. There is a problem of high-temperature flue gas leakage. The outer wall of the boiler adopts a brick wall structure. Since the brick wall is provided with expansion joints, a small amount of high-temperature gas often leaks from the expansion joints, polluting the surrounding environment and endangering the physical and mental health of the staff. In addition, the brick wall needs to be built manually, which is time-consuming and expensive; 3. The high-temperature gas has a complex composition and strong corrosiveness, which causes damage to the outer wall of the boiler, and collapses in severe cases. It is necessary to repair or replace the outer wall from time to time. Since the outer wall needs to be built manually on site, it is difficult to repair and it is difficult to ensure the quality of repair. The above problems will lead to the inability to effectively recover and utilize the waste heat of high-temperature flue gas, so it is urgent to develop a waste heat boiler that can improve the high-temperature flue gas leakage problem and has a good waste heat recovery effect. Utility Model Content

[0004] In order to develop a waste heat boiler that can improve the problem of high-temperature flue gas leakage and has a good waste heat recovery effect, the present application provides a waste heat boiler.

[0005] The waste heat boiler provided in this application adopts the following technical solution:

[0006] A waste heat boiler comprises a boiler drum and a flue gas radiation box, wherein the flue gas radiation box is provided with an inlet flue, an outlet flue and a membrane water-cooled wall, the boiler drum and the membrane water-cooled wall are connected via a downcomer for providing water to the membrane water-cooled wall; the flue gas radiation box is connected to the boiler drum via an upcomer for introducing a steam-water mixture produced by water heated by high temperature flue gas in the membrane water-cooled wall into the boiler drum; a flue gas retention member is also provided in the flue gas radiation box for increasing the residence time of the flue gas in the flue gas radiation box to increase the heat exchange time.

[0007] By adopting the above technical scheme, during operation, the water in the boiler drum enters the flue gas radiation box through the downcomer and is distributed to the membrane water-cooled wall. At the same time, the high-temperature flue gas enters the flue gas radiation box from the inlet flue. The high-temperature flue gas heats the water in the membrane water-cooled wall by radiation in the flue gas radiation box. After the water absorbs heat, a steam-water mixture is generated. The steam-water mixture is introduced into the boiler through the riser to realize water recovery. At the same time, the temperature of the high-temperature flue gas cooled by the membrane water-cooled wall is reduced, and the cooled flue gas is introduced into the subsequent equipment from the outlet flue, thus completing the entire waste heat recovery process. In this process, the flue gas retention member arranged in the flue gas radiation box can increase the high-temperature flue gas in the flue gas radiation. The residence time in the injection box, and thus the time for the high-temperature flue gas to heat the water in the membrane water-cooled wall, that is, to increase the heat exchange time, can produce more steam-water mixture recovery, and can more effectively achieve the purpose of cooling the high-temperature flue gas; the waste heat boiler of the present application has better sealing performance than the brick wall structure of the prior art through the setting of the membrane water-cooled wall, reduces the possibility of leakage of high-temperature flue gas, and achieves the effect of improving the problem of leakage of high-temperature flue gas, and through the coordinated use of the membrane water-cooled wall and the flue gas retention part, the waste heat recovery effect of the high-temperature flue gas can be improved, thereby improving the utilization rate of the high-temperature flue gas, and can also achieve the effect of recycling water, and can reduce the manufacturing cycle and reduce the cost of the boiler.

[0008] In a specific possible implementation manner, the smoke retention member includes a water-cooled wall group, the water-cooled wall group is connected to the membrane water-cooled wall, and the water-cooled wall group and the smoke radiation box together form a plurality of smoke retention cavities.

[0009] By adopting the above technical solution, high-temperature flue gas enters the flue gas radiation box from the inlet flue, and by utilizing the water-cooled wall group and the arrangement of multiple flue gas retention chambers, it is possible to increase the residence time of the high-temperature flue gas in the flue gas radiation box, thereby extending the time for the high-temperature flue gas to heat the water in the membrane water-cooled wall in the flue gas radiation box, thereby increasing the amount of steam-water mixture produced after the water absorbs heat, thereby achieving the effect of improving the waste heat recovery rate and water recovery rate of the high-temperature flue gas.

[0010] In a specific feasible implementation scheme, the water-cooling wall groups are provided in two groups, the two groups of water-cooling wall groups are arranged opposite to each other, each of the water-cooling wall groups is composed of a plurality of water-cooling partition walls, and the water-cooling partition walls in the two groups of water-cooling wall groups are arranged in staggered intervals.

[0011] By adopting the above technical solution and utilizing the staggered arrangement of the water-cooled partition walls in the two groups of water-cooled wall groups, turbulence can be generated in the high-temperature flue gas radiation box, thereby increasing the heat exchange area and heat exchange time between the high-temperature flue gas and water, improving the waste heat recovery efficiency of the high-temperature flue gas, and reducing heat loss in the high-temperature flue gas.

[0012] In a specific possible implementation scheme, the water-cooled partition walls are composed of a plurality of water pipes, and the distance between adjacent water pipes is 40 mm-70 mm.

[0013] By adopting the above technical solution and utilizing the above design method, it is beneficial to form a uniform water flow channel between several water pipes to form a water-cooled partition wall, which is convenient for effectively absorbing and transferring heat and improving heat exchange efficiency; at the same time, the setting of the above tube spacing parameters helps to ensure the stability and strength of the water-cooled partition wall structure.

[0014] In a specific possible implementation scheme, the membrane water-cooled wall is composed of a plurality of water-cooled tubes, the plurality of water-cooled tubes are evenly distributed along the circumference of the flue gas radiation box, and the tube spacing between adjacent water-cooled tubes is 80 mm-120 mm.

[0015] By adopting the above technical solution, by evenly arranging the water-cooling tubes in the circumferential direction inside the flue gas radiation box, it can be ensured that the high-temperature flue gas can contact more water-cooling tubes when passing through the membrane water-cooled wall, thereby achieving more efficient heat exchange; at the same time, the setting of the above-mentioned tube spacing parameters can ensure uniform heat transfer between the water-cooling tubes, avoid local overheating or overcooling, and is conducive to extending the service life of the entire waste heat boiler.

[0016] In a specific possible implementation manner, the flue gas radiation box is further provided with a thermal insulation layer, and the thermal insulation layer is arranged along the circumference of the outer wall of the flue gas radiation box and covers the membrane water-cooled wall.

[0017] By adopting the above technical solution, by combining the insulation layer with the membrane water-cooled wall, not only can the energy loss be effectively reduced, but also the working efficiency of the whole system can be improved; the circumferential uniform distribution of the insulation layer can ensure the overall insulation effect of the flue gas radiation box, and the setting of the insulation layer covering the membrane water-cooled wall helps to reduce the heat loss of the flue gas during the cooling process and improve the heat exchange efficiency.

[0018] In summary, the present application includes at least one of the following beneficial technical effects:

[0019] 1. The waste heat boiler of the present application replaces the brick wall structure of the prior art with a membrane water-cooled wall, which has better sealing performance, reduces the possibility of high-temperature flue gas leakage, and achieves the effect of improving the problem of high-temperature flue gas leakage. In addition, the membrane water-cooled wall and a plurality of water-cooled partition walls of the flue gas retention member are used in coordination to improve the waste heat recovery effect of the high-temperature flue gas, thereby improving the utilization rate of the high-temperature flue gas, and can also achieve the effect of recycling water, and can also reduce the manufacturing cycle and reduce the cost of the boiler;

[0020] 2. The present application utilizes a design that combines the thermal insulation layer with the membrane water-cooled wall, which can not only effectively reduce energy loss, but also improve the working efficiency of the entire system; the circumferential uniform distribution of the thermal insulation layer can ensure the overall thermal insulation effect of the flue gas radiation box, and the arrangement of the thermal insulation layer covering the membrane water-cooled wall helps to reduce the heat loss of the flue gas during the cooling process and improve the heat exchange efficiency;

[0021] 3. The present application uses the staggered arrangement of the water-cooled partition walls in the two groups of water-cooled wall groups to cause turbulence in the high-temperature flue gas in the flue gas radiation box, increase the heat exchange area and heat exchange time between the high-temperature flue gas and water, improve the waste heat recovery efficiency of the high-temperature flue gas, and reduce heat loss in the high-temperature flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the waste heat boiler in the embodiment of the present application.

[0023] Figure 2 It is a cross-sectional view used to show the membrane water-cooled wall and flue gas retention parts inside the flue gas radiation box.

[0024] Explanation of the reference numerals in the accompanying drawings: 1. boiler drum; 2. flue gas radiation box; 21. inlet flue; 22. outlet flue; 23. membrane water-cooled wall; 231. water-cooling pipe; 3. downcomer; 4. upcomer; 5. flue gas retention part; 51. water-cooled wall group; 511. water-cooled partition wall; 512. water pipe; 52. flue gas retention cavity; 6. insulation layer; 7. castable material layer. DETAILED DESCRIPTION

[0025] The following is combined with Figure 1-2 This application is described in further detail.

[0026] Reference Figure 1 , the embodiment of the present application discloses a waste heat boiler, which is designed, manufactured and inspected according to TSG 11-2020 "Technical Regulations for Boiler Safety" and GB / T16507-2022 "Water Tube 512 Boiler";

[0027] The waste heat boiler of the present application includes a drum 1 and a flue gas radiation box 2. The flue gas radiation box 2 is provided with an inlet flue 21, an outlet flue 22 and a membrane water-cooled wall 23. The membrane water-cooled wall 23 is arranged on the inner wall of the flue gas radiation box 2. In the present embodiment, the cross-sectional shape of the flue gas radiation box 2 is rectangular, wherein the length of the flue gas radiation box 2 is 3300 mm and the width is 1900 mm. The flue gas radiation box 2 is a closed box composed of six surfaces, namely, front, rear, left, right, top and bottom. The front, rear, left, right and top five surfaces are composed of membrane water-cooled walls 23, and the bottom surface is composed of a connecting header and flat steel. A reliable sealing design is adopted at the connection of each surface. Specifically, a sealing gasket is installed at the connection of each surface to make it completely fit and cover the connection surface, and then the sealing gasket and the connection surface are welded to form a sealed connection, thereby reducing the air leakage and effectively avoiding the acid gas condensation corrosion caused by the air leakage.

[0028] The boiler drum 1 is connected to the membrane water-cooled wall 23 through the downcomer 3, which provides water for the membrane water-cooled wall 23. In this embodiment, there are two downcomers 3, the outer diameter of the downcomers 3 is 108 mm, the wall thickness of the downcomers 3 is 6 mm, and the material of the downcomers 3 is 20-GB3087; the flue gas radiation box 2 is connected to the boiler drum 1 through the riser 4, which is used to introduce the steam-water mixture produced by the water heated by the high temperature of the flue gas in the membrane water-cooled wall 23 into the boiler drum 1. In this embodiment, there are 11 riser 4s, the outer diameter of the riser 4 is 108 mm, the wall thickness of the riser 4 is 6 mm, and the material of the riser 4 is 20-GB3087; in this embodiment, the inner diameter of the boiler drum 1 is 900 mm, the length of the boiler drum 1 is 4200 mm, and the boiler drum 1 is made of 14 mm thick Q245R steel plate;

[0029] A smoke retention member 5 is also provided in the smoke radiation box 2, which is used to increase the residence time of the smoke in the smoke radiation box 2 to increase the heat exchange time;

[0030] During operation, water in the drum 1 enters the flue gas radiation box 2 through the downcomer 3 and is distributed to the membrane water-cooled wall 23. At the same time, high-temperature flue gas enters the flue gas radiation box 2 from the inlet flue 21. The high-temperature flue gas heats the water in the membrane water-cooled wall 23 by radiation in the flue gas radiation box 2. After the water absorbs heat, a steam-water mixture is generated. The steam-water mixture is introduced into the boiler through the riser 4 to realize water recovery. At the same time, the temperature of the high-temperature flue gas cooled by the membrane water-cooled wall 23 is reduced, and the cooled flue gas is introduced into the subsequent equipment from the outlet flue 22, thus completing the entire waste heat recovery process. In this process, the flue gas retention member 5 provided in the flue gas radiation box 2 can be used to increase the residence time of the high-temperature flue gas in the flue gas radiation box 2, thereby increasing the time for the high-temperature flue gas to heat the water in the membrane water-cooled wall 23, that is, increasing the heat exchange time, thereby improving the waste heat recovery rate and water recovery rate of the high-temperature flue gas, and more effectively achieving the purpose of cooling the high-temperature flue gas.

[0031] The membrane water-cooled wall 23 is composed of a plurality of water-cooled tubes 231, and the plurality of water-cooled tubes 231 are evenly distributed along the circumference of the flue gas radiation box 2; thereby ensuring that the high-temperature flue gas can contact with more water-cooled tubes 231 when passing through the membrane water-cooled wall 23, thereby achieving more efficient heat exchange;

[0032] The tube spacing between adjacent water-cooling tubes 231 is 80mm-120mm. In the present embodiment, the tube spacing between adjacent water-cooling tubes 231 is 100mm; thereby ensuring uniform heat transfer between the water-cooling tubes 231, avoiding local overheating or overcooling, and being beneficial to extending the service life of the entire waste heat boiler.

[0033] The smoke retention member 5 includes a water-cooled wall group 51, the water-cooled wall group 51 is connected to the membrane water-cooled wall 23, and the water-cooled wall group 51 and the smoke radiation box 2 together form a plurality of smoke retention chambers 52;

[0034] The water-cooling wall groups 51 are set as two groups, and the two groups of water-cooling wall groups 51 are arranged opposite to each other. The water-cooling wall groups 51 are each composed of a plurality of water-cooling partition walls 511. In this embodiment, the water-cooling wall groups 51 are each composed of two water-cooling partition walls 511, and the water-cooling partition walls 511 in the two groups of water-cooling wall groups 51 are arranged in a staggered manner; thereby, the high-temperature flue gas can generate turbulence in the flue gas radiation box 2, increase the heat exchange area and heat exchange time between the high-temperature flue gas and water, improve the waste heat recovery efficiency of the high-temperature flue gas, and reduce the heat loss in the high-temperature flue gas;

[0035] The water-cooled partition wall 511 is composed of a plurality of water pipes 512, and the distance between adjacent water pipes 512 is 40 mm to 70 mm. In this embodiment, the distance between adjacent water pipes 512 is 55 mm. This is conducive to forming a uniform water flow channel between the plurality of water pipes 512 to form the water-cooled partition wall 511, which is convenient for effectively absorbing and transferring heat and improving heat exchange efficiency. At the same time, the setting of the above-mentioned tube spacing parameters helps to ensure the stability and strength of the water-cooled partition wall 511 structure.

[0036] During operation, high-temperature flue gas enters the flue gas radiation box 2 from the inlet flue 21, heats the membrane water-cooled wall 23 in the flue gas radiation box 2 by radiation, and then dissipates from the outlet flue 22. In this process, by setting up a plurality of water-cooled partition walls 511 and a plurality of flue gas retention chambers 52, the residence time of the high-temperature flue gas in the flue gas radiation box 2 can be increased, thereby extending the time for the high-temperature flue gas to heat the water in the membrane water-cooled wall 23 in the flue gas radiation box 2, and further increasing the amount of steam-water mixture produced after the water absorbs heat, thereby achieving the effect of improving the waste heat recovery rate and water recovery rate of the high-temperature flue gas.

[0037] The inlet flue 21 and the outlet flue 22 are both formed by a castable layer 7, and the castable layer 7 is sealed and connected to the membrane water-cooled wall 23; thereby ensuring that the flue gas will not leak when passing through the membrane water-cooled wall 23, thereby achieving the purpose of effective heat dissipation and heat exchange. At the same time, the sealed connection can also prevent external air from entering the flue, maintain the purity and stability of the flue gas, and can also fix the entire membrane water-cooled wall 23 structure to ensure the safe and stable operation of the flue gas radiation box 2;

[0038] The castable layer 7 is a high-aluminum refractory material layer or a high-silicon refractory material layer. In the present embodiment, the high-aluminum refractory material layer is made of a refractory material having an aluminum oxide content greater than 45%, and has good high temperature resistance, erosion resistance, and wear resistance. The high-silicon refractory material layer is made of a refractory material having a silicon dioxide content greater than 93%, and has very high high temperature resistance, erosion resistance, and wear resistance. This can effectively improve the fire resistance and sealing properties of the flue, effectively protect the flue structure, maintain the stability of the structure, and ensure the stable operation of the entire waste heat boiler.

[0039] The flue gas radiation box 2 is also provided with an insulation layer 6, which is arranged along the circumference of the outer wall of the flue gas radiation box 2 and covers the membrane water-cooled wall 23. In the present embodiment, the material of the insulation layer 6 includes but is not limited to mineral wool, glass wool, foam plastic, and polystyrene board; by combining the insulation layer 6 with the membrane water-cooled wall 23, not only can the energy loss be effectively reduced, but also the working efficiency of the whole system can be improved; the circumferential uniform distribution of the insulation layer 6 can ensure the overall insulation effect of the flue gas radiation box 2, and the arrangement of the insulation layer 6 covering the membrane water-cooled wall 23 helps to reduce the heat loss of the flue gas during the cooling process and improve the heat exchange efficiency.

[0040] A water distribution pipe is also provided in the boiler drum 1, which is used to evenly introduce water into the interior of the boiler drum 1, ensure that the water level in the boiler drum 1 is stable, and avoid operational problems caused by unstable water level; a steam-water separation device is used to effectively separate the steam and water of the steam-water mixture introduced into the boiler drum 1; a continuous sewage pipe is used to discharge sewage and impurities in the boiler drum 1 to prevent sewage accumulation from affecting the normal operation of the boiler system; a water level gauge is used to monitor the height of the water level in the boiler to ensure that the water level operates stably within a safe range; a pressure gauge is used to monitor the pressure conditions inside the boiler to ensure that the boiler operates within a normal range. By monitoring the pressure changes of the boiler in real time, the operating parameters can be adjusted in time to avoid safety accidents caused by overpressure or low pressure; a pressure safety valve is a device for safety protection. When the internal pressure of the boiler exceeds the set value, the pressure safety valve will automatically start to release over-pressure steam or gas to protect the boiler drum 1 from damage and ensure safe operation.

[0041] The waste heat boiler of the present application adopts a membrane water-cooled wall 23 to replace the brick wall structure in the prior art, which reduces the weight of the boiler furnace wall by about 60% and the total cost by about 30%. The membrane water-cooled wall 23 has good sealing performance, reduces the leakage of high-temperature flue gas, reduces environmental pollution, and protects the physical and mental health of operators. The waste heat boiler of the present application has been put into use since May 2020. During operation, it was only shut down for maintenance twice due to the falling off of the castable layer 7, causing damage to the inlet flue 21 and the outlet flue 22. Each maintenance time only takes about one day. The maintenance is visible and the maintenance time is short. It can be put into use quickly, and it can also reduce the manufacturing cycle and reduce the cost of the boiler.

[0042] The implementation principle of a waste heat boiler in the embodiment of the present application is as follows: the waste heat boiler of the present application replaces the brick wall structure of the prior art with a membrane water-cooled wall 23, which has better sealing performance, reduces the possibility of high-temperature flue gas leakage, and achieves the effect of improving the problem of high-temperature flue gas leakage. In addition, the membrane water-cooled wall 23 and the several water-cooled partition walls 511 of the flue gas retention member 5 are used in coordination to improve the waste heat recovery effect of the high-temperature flue gas, thereby improving the utilization rate of the high-temperature flue gas, and also achieving the effect of water recovery.

[0043] During operation, water in the drum 1 enters the flue gas radiation box 2 through the downcomer 3 and is distributed to the membrane water-cooled wall 23. At the same time, high-temperature flue gas enters the flue gas radiation box 2 from the inlet flue 21. The high-temperature flue gas heats the water in the membrane water-cooled wall 23 by radiation in the flue gas radiation box 2. After the water absorbs heat, a steam-water mixture is generated. The steam-water mixture is introduced into the boiler through the riser 4 to realize water recovery. At the same time, the temperature of the high-temperature flue gas cooled by the membrane water-cooled wall 23 is reduced, and the cooled flue gas is introduced into the subsequent equipment from the outlet flue 22, thus completing the entire waste heat recovery process.

[0044] During the movement of high-temperature flue gas in the flue gas radiation box 2, the setting of several water-cooled partition walls 511 and multiple flue gas retention chambers 52 can increase the residence time of the high-temperature flue gas in the flue gas radiation box 2, thereby extending the time for the high-temperature flue gas to heat the water in the membrane water-cooled wall 23 in the flue gas radiation box 2, and further increasing the amount of steam-water mixture produced after the water absorbs heat, thereby achieving the effect of improving the waste heat recovery rate of the high-temperature flue gas and the water recovery rate.

[0045] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A waste heat boiler, characterized in that: The invention comprises a boiler drum (1) and a flue gas radiation box (2), wherein the flue gas radiation box (2) is provided with an inlet flue (21), an outlet flue (22) and a membrane water-cooled wall (23), wherein the boiler drum (1) and the membrane water-cooled wall (23) are connected via a downcomer (3) for providing water to the membrane water-cooled wall (23); the flue gas radiation box (2) and the boiler drum (1) are connected via an upcomer (4) for introducing a steam-water mixture generated by water heated by high-temperature flue gas in the membrane water-cooled wall (23) into the boiler drum (1); and a flue gas retention member (5) is further provided in the flue gas radiation box (2) for increasing the residence time of the flue gas in the flue gas radiation box (2) so as to increase the heat exchange time.

2. The waste heat boiler according to claim 1, characterized in that: The smoke retention member (5) comprises a water-cooled wall group (51), the water-cooled wall group (51) is connected to the membrane water-cooled wall (23), and the water-cooled wall group (51) and the smoke radiation box (2) together form a plurality of smoke retention cavities (52).

3. The waste heat boiler according to claim 2, characterized in that: The water-cooling wall groups (51) are provided in two groups, the two groups of water-cooling wall groups (51) are arranged opposite to each other, each of the water-cooling wall groups (51) comprises a plurality of water-cooling partition walls (511), and the water-cooling partition walls (511) in the two groups of water-cooling wall groups (51) are arranged in a staggered manner.

4. The waste heat boiler according to claim 3, characterized in that: The water-cooling partition walls (511) are composed of a plurality of water pipes (512), and the distance between adjacent water pipes (512) is 40 mm to 70 mm.

5. The waste heat boiler according to claim 1, characterized in that: The membrane water-cooled wall (23) is composed of a plurality of water-cooling tubes (231), and the plurality of water-cooling tubes (231) are evenly distributed along the circumference of the flue gas radiation box (2), and the tube spacing between adjacent water-cooling tubes (231) is 80 mm-120 mm.

6. The waste heat boiler according to claim 1, characterized in that: The flue gas radiation box (2) is also provided with a heat-insulating layer (6), and the heat-insulating layer (6) is arranged along the circumference of the outer wall of the flue gas radiation box (2) and covers the membrane water-cooled wall (23).

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