Passive cooling sandwich structure of flexible tube plate of waste heat boiler and boiler system based on passive cooling sandwich structure

Abstract

The invention relates to the technical field of cooling of flexible tube plates of waste pots, in particular to a passive cooling sandwich structure of a flexible tube plate of a waste pot and a boiler system based on the passive cooling sandwich structure, and aims to solve the cooling problem of the flexible tube plate at the upper part of a vertical fire tube waste pot. The interlayer structure comprises a flexible pipe plate, a circulating water inlet assembly, a circulating water outlet assembly and a sealing partition plate. The flexible tube plate is connected with the top of a heat exchange tube bundle in a waste heat boiler to fix the heat exchange tube bundle, the flexible tube plate and the sealing partition plate are sequentially fixed in the waste heat boiler from top to bottom, an interlayer is formed between the flexible tube plate and the sealing partition plate, and the circulating water inlet assembly and the circulating water outlet assembly are connected with the waste heat boiler. And the circulating water inlet assembly and the circulating water outlet assembly are both communicated with the interlayer, the circulating water inlet assembly is arranged at the low point of the interlayer, the circulating water outlet assembly is arranged at the high point of the interlayer, and by means of the scheme, independent cooling of the flexible pipe plate is efficiently and stably achieved in an energy-saving mode.

Description

Technical Field

[0001] The invention relates to the technical field of flexible tube sheet cooling of waste boilers, and in particular to a passive cooling sandwich structure of a flexible tube sheet of a waste boiler and a boiler system based thereon. Background Art

[0002] In the petrochemical industry, especially the coal chemical industry, there are many waste heat recovery boilers. When the waste heat recovery medium has a high ash content and a high temperature, a vertical fire tube plus a flexible tube sheet structure is generally used: the ash volume is large, and all structural types involving horizontal flow will be blocked due to ash accumulation, such as horizontal structures, vertical U-shaped structures, etc.; the temperature is high, and the fire tube structure with thick tube sheets will fail due to overheating caused by the inability to cool the tube sheets. Therefore, there are two types of vertical fire tube flexible tube sheet waste boilers and vertical serpentine tube water pipe waste boilers. Since the serpentine tube waste boiler has a complex structure and is difficult to manufacture, it generally requires a vibrating device for cleaning, so the mainstream solution is the natural convection vertical fire tube flexible tube sheet waste boiler.

[0003] Vertical fire tube flexible tube sheet waste boiler refers to the process in which the waste heat medium flows through the tubes of the heat exchanger (i.e., fire tubes). The overall structure is vertical, the heat exchange tubes are tube-in-tube type (i.e., straight tubes), and the tube sheets are flexible tube sheets. For ash-containing media, there will be no ash accumulation problem because the medium flows from top to bottom in the tube. The shell side medium inlet is saturated water, and the outlet is saturated steam and water. It flows from bottom to top, absorbs heat from the tube side medium to evaporate, and cools the heat exchange tubes to ensure that the average wall temperature of the heat exchange tubes is consistent with that of the shell, avoiding expansion and damage caused by excessive temperature difference. The use of natural convection means that the steam-water circulation on the shell side is a natural convection circulation. The circulating water will automatically circulate under the action of density difference and height difference, and no additional driving force is required.

[0004] However, since the tube sheet is densely covered with heat exchange tubes, the high-temperature medium in the tube will continuously transfer heat to the tube sheet. If the heat of the tube sheet cannot be removed in time, the tube sheet will fail due to overheating. Therefore, the tube sheet must be a thin tube sheet, that is, a flexible tube sheet. For the flexible tube sheet at the bottom of the waste boiler, since it can fully contact with the circulating water, the heat can be stably taken away by the circulating water to ensure that its temperature is within the allowable range. However, for the upper tube sheet, since the circulating water has completed the entire heat exchange process, the volume steam content of the circulating water will be higher (~50%) at this time. Under the action of gravity, the steam will tend to be in the upper layer of the steam-water flow, resulting in the main contact with the upper tube sheet being the steam, and the heat exchange capacity of the steam is poor, and it is impossible to ensure the heat of the tube sheet, which is easy to cause the tube sheet to fail due to overheating. Summary of the invention

[0005] The purpose of the patent of this invention: The content of this invention is to solve the cooling problem of the upper flexible tube sheet of the vertical fire tube waste boiler, ensure its operating stability, and maintain the temperature of the upper flexible tube sheet within the allowable range. The present invention provides a passive cooling sandwich structure of the waste boiler flexible tube sheet and a boiler system based thereon.

[0006] The object of the present invention is achieved as follows: a passive cooling sandwich structure of a waste boiler flexible tube sheet, characterized in that: the sandwich structure is used to be arranged in a vertical waste boiler, the sandwich structure is located at the upper part of the heat exchange tube bundle in the waste boiler, and the sandwich structure includes a flexible tube sheet, a circulating water inlet assembly, a circulating water outlet assembly and a sealing baffle;

[0007] The flexible tube sheet is connected to the top of the heat exchange tube bundle in the waste boiler to fix the heat exchange tube bundle. The flexible tube sheet and the sealing baffle are fixed in the waste boiler from top to bottom in sequence. A sandwich is formed between the flexible tube sheet and the sealing baffle. The circulating water inlet assembly and the circulating water outlet assembly are connected to the waste boiler, and the circulating water inlet assembly and the circulating water outlet assembly are both connected to the sandwich. The circulating water inlet assembly is arranged at the low point of the sandwich, and the circulating water outlet assembly is arranged at the high point of the sandwich.

[0008] Furthermore, an upwardly disposed annular groove is provided between the flexible tube plate and the inner wall of the waste boiler.

[0009] Still further, the sandwich structure further comprises at least one pair of baffles;

[0010] Each pair of baffles is symmetrically arranged in the interlayer and fixed on the inner wall of the waste pot.

[0011] Further, the sealing partition includes a partition, a plurality of ring plates and a plurality of bolts;

[0012] A plurality of ring plates are fixed on the inner wall of the waste pot, a partition plate is placed above the plurality of ring plates, and the partition plate is fixed to each ring plate by a bolt.

[0013] Furthermore, the plurality of ring plates are evenly distributed along the circumferential direction.

[0014] Further, the circulating water inlet assembly includes an inlet pipe and a distribution pipe;

[0015] The distribution pipe is an arc-shaped curved pipe, which is arranged in the interlayer and has a plurality of water outlet holes evenly distributed on the distribution pipe; the inlet pipe passes through the side wall of the waste boiler and is connected with the distribution pipe.

[0016] Furthermore, the inlet pipe is communicated with the middle part of the distribution pipe.

[0017] Furthermore, the circulating water outlet assembly includes an outlet pipe, a main confluence pipe and a plurality of branch pipes;

[0018] The inlet ends of the multiple branch pipes are communicated with the interlayer, the outlet ends of the multiple branch pipes are communicated with a main confluence pipe arranged outside the waste boiler, and the inlet end of the outlet pipe is communicated with the outlet end of the main confluence pipe.

[0019] Further, a boiler system based on a waste boiler flexible tube sheet passive cooling sandwich structure comprises a waste boiler, a steam drum, a downcomer, an upcomer and a sandwich structure;

[0020] The waste boiler is arranged vertically and tilted, the axis of the waste boiler forms an angle α with the vertical direction, and the steam drum is placed above the waste boiler;

[0021] The outlet end of the drum is connected to the inlet end of the downcomer, the outlet end of the downcomer is connected to the downcomer main line and the downcomer branch line, and the downcomer branch line is connected to the inlet pipe;

[0022] The inlet end of the drum is connected to the outlet end of the riser, and the inlet end of the riser is connected to the main riser and the branch riser; the branch riser is connected to the outlet pipe;

[0023] The main downcomer and the main upcomer are both arranged on the waste boiler side wall between the flexible tube sheets connected on both sides of the heat exchange tube bundle in the waste boiler and connected. The main downcomer is located above the flexible tube sheet below, and the main upcomer is located below the sealing partition.

[0024] Beneficial effects:

[0025] This solution solves the problem of cooling the flexible tube sheet of a natural circulation vertical fire tube waste boiler. The cooling interlayer not only has a reliable sealing structure, an inclined setting that is conducive to the natural flow of steam, an evenly distributed inlet and outlet structure, and a baffle that improves the utilization rate of circulating water, but also adopts a passive form in the system layout to allow the interlayer water circulation to have the maximum natural circulation driving force, thereby achieving independent cooling of the flexible tube sheet in an efficient, stable and energy-saving manner, ensuring the safe, reliable and energy-saving operation of the vertical fire tube waste boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the waste boiler flexible tube sheet passive cooling sandwich structure and the boiler system based thereon of the present invention;

[0027] Figure 2 yes Figure 1 AA view;

[0028] Figure 3 yes Figure 1 Enlarged view of point I. DETAILED DESCRIPTION

[0029] Specific implementation method 1: a passive cooling sandwich structure of a waste boiler flexible tube sheet, the sandwich structure is used to be arranged in a vertical waste boiler 1, the sandwich structure is located at the upper part of the heat exchange tube bundle in the waste boiler 1, and the sandwich structure includes a flexible tube sheet 1-1, a circulating water inlet assembly 1-2, a circulating water outlet assembly 1-3 and a sealing baffle 1-4;

[0030] The flexible tube sheet 1-1 is connected to the top of the heat exchange tube bundle in the waste boiler 1 to fix the heat exchange tube bundle. The flexible tube sheet 1-1 and the sealing baffle 1-4 are fixed in the waste boiler 1 from top to bottom in sequence. A sandwich is formed between the flexible tube sheet 1-1 and the sealing baffle 1-4. The circulating water inlet assembly 1-2 and the circulating water outlet assembly 1-3 are connected to the waste boiler 1, and the circulating water inlet assembly 1-2 and the circulating water outlet assembly 1-3 are both connected to the sandwich. The circulating water inlet assembly 1-2 is set at the low point of the sandwich, and the circulating water outlet assembly 1-3 is set at the high point of the sandwich.

[0031] Specific implementation method 2: A waste boiler flexible tube sheet passive cooling sandwich structure, wherein an upwardly disposed annular groove is provided between the flexible tube sheet 1 - 1 and the inner wall of the waste boiler 1 .

[0032] In this embodiment, the protrusion of the flexible tube sheet is set downward, and an upward groove is formed around the inner wall of the waste boiler. The steam generated in the interlayer will be collected at the groove after flowing out of the tube bundle, and then flow into the circulating water inlet assembly 1-2 along the groove, and the flow channel will be smoother, which can reduce the risk of steam accumulation on the lower surface of the tube sheet and improve the cooling effect.

[0033] Other implementations are the same as the first specific implementation.

[0034] Specific implementation method three: a passive cooling sandwich structure of a waste boiler flexible tube sheet, wherein the sandwich structure further comprises at least one pair of baffles 1-5;

[0035] Each pair of baffles 1 - 5 are symmetrically arranged in the interlayer and fixed on the inner wall of the waste pot 1 .

[0036] In this embodiment: the circulating water inlet assembly is composed of an inlet pipe and a distribution pipe. The distribution pipe is arranged in the gap between the tube bundle and the shell, and is symmetrically arranged with a certain angle to both sides. Holes are opened on the distribution pipe at a certain distance toward the center of the tube bundle. The circulating water flowing from the inlet pipe will be evenly distributed in the interlayer through the distribution pipe, improving the uniformity of the flow field and reducing the risk of flow dead zones (also known as cooling dead zones), thereby ensuring the cooling effect. The circulating water inlet assembly needs to be arranged at the lowest point of the interlayer to match the flow direction of the gas.

[0037] Other implementations are the same as the first specific implementation.

[0038] Specific implementation method four: waste boiler flexible tube sheet passive cooling sandwich structure, the sealing partition 1-4 includes a partition 1-4-1, a plurality of ring plates 1-4-2 and a plurality of bolts 1-4-3;

[0039] A plurality of ring plates 1-4-2 are fixed on the inner wall of the waste pot 1, a partition plate 1-4-1 is placed above the plurality of ring plates 1-4-2, and the partition plate 1-4-1 is fixed to each ring plate 1-4-2 by a bolt 1-4-3.

[0040] In this embodiment: the ring plate is firstly welded to the cylinder wall, then bolts are welded, and then the partition plate is fastened, and finally nuts are tightened. The partition plate is a whole circular plate, and the bolt group is evenly arranged in the overlapping area of ​​the partition plate and the ring plate. By tightening the nuts, the partition plate and the ring plate are ensured to be close to each other, that is, a separate sandwich structure is isolated at the top of the waste shell.

[0041] Other implementations are the same as the first specific implementation.

[0042] Specific implementation method five: a waste boiler flexible tube sheet passive cooling sandwich structure, a plurality of ring plates 1-4-2 are evenly distributed along the circumferential direction.

[0043] Other implementations are the same as the first specific implementation.

[0044] Specific implementation method six: waste boiler flexible tube sheet passive cooling sandwich structure, the circulating water inlet assembly 1-2 includes an inlet pipe 1-2-1 and a distribution pipe 1-2-2;

[0045] The distribution pipe 1-2-2 is an arc-shaped curved pipe, which is arranged in the interlayer and has a plurality of water outlet holes evenly distributed on the distribution pipe 1-2-2; the inlet pipe 1-2-1 passes through the side wall of the waste boiler 1 and is connected with the distribution pipe 1-2-2.

[0046] In this embodiment: the circulating water inlet assembly consists of an inlet pipe and a distribution pipe. The distribution pipe is arranged in the gap between the tube bundle and the shell, and is symmetrically arranged with a certain angle to both sides. Holes are opened on the distribution pipe at a certain distance toward the center of the tube bundle. The circulating water flowing from the inlet pipe will be evenly distributed in the interlayer through the distribution pipe, improving the uniformity of the flow field and reducing the risk of flow dead zones (also known as cooling dead zones), thereby ensuring the cooling effect. The circulating water inlet assembly needs to be arranged at the lowest point of the interlayer to match the flow direction of the gas.

[0047] Other implementations are the same as the fourth specific implementation.

[0048] Specific implementation method seven: The passive cooling sandwich structure of the waste boiler flexible tube sheet, the inlet pipe 1-2-1 is connected with the middle part of the distribution pipe 1-2-2.

[0049] In this embodiment: other embodiments are the same as the first embodiment.

[0050] Specific implementation eight: waste boiler flexible tube sheet passive cooling sandwich structure, the circulating water outlet assembly 1-3 includes an outlet pipe 1-3-1, a main confluence pipe 1-3-2 and a plurality of branch pipes 1-3-3;

[0051] The inlet ends of the multiple branch pipes 1-3-3 are connected to the interlayer, the outlet ends of the multiple branch pipes 1-3-3 are connected to the main confluence pipe 1-3-2 arranged outside the waste boiler 1, and the inlet end of the outlet connecting pipe 1-3-1 is connected to the outlet end of the main confluence pipe 1-3-2.

[0052] In this embodiment: the circulating water outlet assembly is composed of an outlet pipe, a main confluence pipe, and a branch pipe. The circulating water outlet assembly needs to be arranged at the highest point of the interlayer to match the flow direction of the steam. Multiple branch pipes are provided, which are symmetrically arranged on both sides of the highest point of the interlayer. The circulating water (saturated steam-water state) drawn out from the branch pipes is collected in the main confluence pipe, and then flows out from the outlet pipe. Arranging multiple branch pipes at the outlet can improve the uniformity of the circulating water outflow and avoid the accumulation of a large amount of steam in one place, thereby ensuring the cooling effect. The steam flowing out of the tube bundle will converge in the groove of the flexible tube sheet. In order to improve the efficiency of discharging the steam, the center line of the branch pipe needs to be higher than the lower surface of the flexible tube sheet to further improve the cooling effect.

[0053] Other implementations are the same as the sixth specific implementation.

[0054] Specific implementation method 9: A boiler system based on a waste boiler flexible tube sheet passive cooling sandwich structure, which includes a waste boiler 1, a steam drum 2, a downcomer 3, an upcomer 4 and a sandwich structure;

[0055] The waste boiler 1 is arranged vertically and tilted, the axis of the waste boiler 1 forms an angle α with the vertical direction, and the steam drum 2 is placed above the waste boiler 1;

[0056] The outlet end of the drum 2 is connected to the inlet end of the downcomer 3, the outlet end of the downcomer 3 is connected to the downcomer main line 3-1 and the downcomer branch line 3-2, and the downcomer branch line 3-2 is connected to the inlet pipe 1-2-1;

[0057] The inlet end of the drum 2 is connected to the outlet end of the riser 4, and the inlet end of the riser 4 is connected to the riser main line 4-1 and the riser branch line 4-2; the riser branch line 4-2 is connected to the outlet pipe 1-3-1;

[0058] The downcomer main line 3-1 and the upcomer main line 4-1 are both arranged on the side wall of the waste boiler 1 between the flexible tube sheets 1-1 connected on both sides of the heat exchange tube bundle in the waste boiler 1 and are connected. The downcomer main line 3-1 is located above the flexible tube sheet 1-1 below, and the upcomer main line 4-1 is located below the sealing partition 1-4.

[0059] In this embodiment: the waste boiler is arranged as a whole at an angle, and the axis of the equipment forms an angle α with the vertical direction. The circulating water entering the interlayer will also be partially vaporized in the interlayer due to heat absorption (but due to the small heat transfer area of ​​the interlayer, the steam production will be much smaller than the mainstream, and the volume steam content is less than 5%). After the waste boiler is arranged at an angle, the steam generated in the interlayer will naturally flow upward along the lower surface of the flexible tube sheet, which can reduce the risk of remaining on the lower surface of the tube sheet and improve the cooling effect.

[0060] The circulating water in the drum enters the bottom of the shell side of the waste boiler from the downcomer, and continuously bends upward in the shell side and exchanges heat with the tube bundle. Since the circulating water in the downcomer is nearly saturated, it will evaporate due to heat absorption and become saturated steam and water. Obviously, the more saturated water evaporates upward, the greater the saturated steam content will be, and the saturated steam volume steam content will be ~50% at the outlet. The circulating water (saturated steam and water state) that has exchanged heat enters the riser from the outlet at the top of the waste boiler and finally returns to the drum. Since the circulating water in the downcomer is nearly saturated, its density is the density of water, while the circulating water in the shell side of the waste boiler and the riser is saturated steam and water, so its density is smaller. The density difference between the media in the downward process and the upward process will form a pressure difference, which will cause the natural flow of the media, that is, natural circulation, which is also passive.

[0061] The circulation power of the natural circulation waste boiler is due to the density difference of the medium in the downward process and the upward process, which in turn forms a pressure difference and causes flow. Obviously, the pressure difference is related to the density difference and the height difference. The greater the density difference and the height difference, the greater the total pressure difference, the faster the flow, and the better the cooling effect. The circulating water from the downcomer does not participate in the heat exchange, so the density in the downcomer main line and the downcomer branch is the same. The circulating water that flows into the riser, as mentioned above, has a volume vapor content of ~50% in the main riser, and a volume vapor content of only ~5% in the branch riser. Therefore, the circulating water in the main riser has a lower density.

[0062] In order to ensure that the circulating water in the downcomer branch has a small flow resistance, the downcomer branch is required to be connected from the nearest part of the downcomer. In order to ensure that the riser branch has a small flow resistance, the riser needs to be connected at a closer location; but at the same time, in order to ensure that the upward process has a lower density, the riser needs to be connected at a level close to the circulating water outlet component, so that the outlet circulating water of the entire interlayer within the height difference range (i.e. the distance between the interlayer and the steam drum) is the medium density of the riser main line. Not only does it achieve passiveness, but it also further ensures the cooling effect.

[0063] Working principle: This scheme adopts a sandwich structure that cools down its flexible tube sheet in a passive form. Its main components include: downcomers, upcomers, flexible tube sheets, circulating water inlet components, circulating water outlet components, sealing baffles, baffles, etc. The flexible tube sheet and the sealing baffle form a closed sandwich structure. A circulating water inlet component is arranged near the bottom, and a circulating water outlet component is arranged near the top. The circulating water inlet component introduces circulating water from the downcomer. The circulating water flows in the sandwich to cool the flexible tube sheet and then flows into the circulating water outlet component, and finally returns to the upcomer. Anti-short-circuit baffles are arranged in the non-pipe areas on both sides of the sandwich. The cooling sandwich structure adopts natural circulation as the driving force, which is a passive form. The flexible tube sheet is cooled down separately in the smaller sandwich, which improves the cooling stability of the flexible tube sheet and ensures that the flexible tube sheet does not fail due to overheating.

Claims

1. The passive cooling sandwich structure of the waste boiler flexible tube sheet is characterized by: The sandwich structure is used to be arranged in a vertical waste boiler (1), the sandwich structure is located at the upper part of the heat exchange tube bundle in the waste boiler (1), and the sandwich structure comprises a flexible tube sheet (1-1), a circulating water inlet assembly (1-2), a circulating water outlet assembly (1-3) and a sealing baffle (1-4); The flexible tube sheet (1-1) is connected to the top of the heat exchange tube bundle in the waste boiler (1) to fix the heat exchange tube bundle. The flexible tube sheet (1-1) and the sealing baffle (1-4) are fixed in the waste boiler (1) in sequence from top to bottom. An interlayer is formed between the flexible tube sheet (1-1) and the sealing baffle (1-4). The circulating water inlet assembly (1-2) and the circulating water outlet assembly (1-3) are connected to the waste boiler (1), and the circulating water inlet assembly (1-2) and the circulating water outlet assembly (1-3) are both connected to the interlayer. The circulating water inlet assembly (1-2) is arranged at a low point of the interlayer, and the circulating water outlet assembly (1-3) is arranged at a high point of the interlayer.

2. The waste boiler flexible tube sheet passive cooling sandwich structure according to claim 1 is characterized in that: An upwardly disposed annular groove is provided between the flexible tube plate (1-1) and the inner wall of the waste pot (1).

3. The waste boiler flexible tube sheet passive cooling sandwich structure according to claim 1, characterized in that: The sandwich structure also includes at least one pair of baffles (1-5); Each pair of baffles (1-5) are symmetrically arranged in the interlayer and fixed on the inner wall of the waste pot (1).

4. The waste boiler flexible tube sheet passive cooling sandwich structure according to claim 1, characterized in that: The sealing partition (1-4) comprises a partition (1-4-1), a plurality of ring plates (1-4-2) and a plurality of bolts (1-4-3); A plurality of ring plates (1-4-2) are fixed on the inner wall of the waste pot (1), a partition plate (1-4-1) is placed above the plurality of ring plates (1-4-2), and the partition plate (1-4-1) and each ring plate (1-4-2) are fixed by a bolt (1-4-3).

5. The passive cooling sandwich structure of the waste boiler flexible tube sheet according to claim 4 is characterized in that: A plurality of ring plates (1-4-2) are evenly distributed along the circumferential direction.

6. The waste boiler flexible tube sheet passive cooling sandwich structure according to claim 1, characterized in that: The circulating water inlet assembly (1-2) comprises an inlet pipe (1-2-1) and a distribution pipe (1-2-2); The distribution pipe (1-2-2) is an arc-shaped curved pipe, which is arranged in the interlayer and has a plurality of water outlet holes evenly distributed on the distribution pipe (1-2-2); the inlet pipe (1-2-1) passes through the side wall of the waste boiler (1) and is connected to the distribution pipe (1-2-2).

7. The waste boiler flexible tube sheet passive cooling sandwich structure according to claim 6, characterized in that: The inlet pipe (1-2-1) is connected to the middle part of the distribution pipe (1-2-2).

8. The waste boiler flexible tube sheet passive cooling sandwich structure according to claim 1, characterized in that: The circulating water outlet assembly (1-3) comprises an outlet pipe (1-3-1), a main confluence pipe (1-3-2) and a plurality of branch pipes (1-3-3); The inlet ends of the multiple branch pipes (1-3-3) are connected to the interlayer, the outlet ends of the multiple branch pipes (1-3-3) are connected to a main confluence pipe (1-3-2) arranged outside the waste boiler (1), and the inlet end of the outlet pipe (1-3-1) is connected to the outlet end of the main confluence pipe (1-3-2).

9. A boiler system based on the sandwich structure according to any one of claims 1 to 8, characterized in that: It comprises a waste boiler (1), a steam drum (2), a downcomer (3), an ascending pipe (4) and a sandwich structure; The waste boiler (1) is arranged vertically and tilted, the axis of the waste boiler (1) forms an angle α with the vertical direction, and the steam drum (2) is placed above the waste boiler (1); The outlet end of the steam drum (2) is connected to the inlet end of the downcomer (3), the outlet end of the downcomer (3) is connected to the downcomer main line (3-1) and the downcomer branch line (3-2), and the downcomer branch line (3-2) is connected to the inlet pipe (1-2-1); The inlet end of the steam drum (2) is connected to the outlet end of the riser (4); the inlet end of the riser (4) is connected to the riser main line (4-1) and the riser branch line (4-2); the riser branch line (4-2) is connected to the outlet pipe (1-3-1); The downpipe main path (3-1) and the uppipe main path (4-1) are both arranged on the side wall of the waste boiler (1) between the flexible tube sheets (1-1) connected on both sides of the heat exchange tube bundle in the waste boiler (1) and are connected. The downpipe main path (3-1) is located above the lower flexible tube sheet (1-1), and the uppipe main path (4-1) is located below the sealing partition (1-4).

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