Heating furnace tail gas heat recycling device

Abstract

The present application relates to the technical field of flue gas waste heat recovery of flue gas heat treatment furnaces, and in particular to a heat recycling device for exhaust gas of a heating furnace, which includes a flue connecting pipe, a water tank, a steam generator, a duct device, and a waste heat utilization device, wherein the steam generator is installed on the flue connecting pipe, the duct device is installed on the end of the steam generator away from the flue connector, the waste heat utilization device is installed on the duct device, and the water tank is on one side, and the water tank is respectively connected to the steam generator, the duct device, and the waste heat utilization device, and the waste heat utilization device and the duct device preheat the cold water in the water tank for the steam generator to quickly generate steam. In the present application, since a water tank and a steam generator are provided, cold water enters the sealing cover through a water inlet pipe A, and the cold water dripping onto the thin flue will instantly evaporate into steam, which can reduce the probability of scaling on the thin flue, and the cold water will not be heated all at once, the efficiency of steam generation is high, and most of the heat is used in the program.

Description

Technical Field

[0001] The present application relates to the technical field of waste heat recovery of flue gas from a steel wire heat treatment furnace, and in particular to a device for recycling heat from exhaust gas from a heating furnace. Background Art

[0002] Steel wire is one of the four major types of steel: plate, tube, profile and wire. It is a reprocessed product made from hot-rolled wire rods by cold drawing. The main processes of steel wire production include raw material selection, removal of iron oxide scale, drying, coating treatment, heat treatment, wire drawing, plating treatment, etc. The steel wire open flame heating furnace is a device for heat treatment of steel wire. There are preheating section, heating section and soaking section in the furnace. The temperature and air-fuel ratio of each section are different. The running direction of the steel wire is opposite to the running direction of the flue gas. The heating furnace, as a large energy consumer, directly affects the production cost of the enterprise. Generally, the thermal efficiency of the heating furnace as a heating equipment is generally around 30%, with high energy consumption and low energy utilization level, resulting in a large amount of energy waste. Therefore, recycling the waste heat of the heating furnace has both good economic benefits and certain environmental benefits. At present, the high-temperature flue gas of about 400 degrees discharged from the tail of the heating furnace is directly discharged through the chimney without recycling, resulting in a waste of resources.

[0003] Through searching, Chinese patent: CN210689245U discloses a waste heat recovery steam generator for a steel wire heat treatment furnace, including a heat exchange device, a water cooling box and an air induced device. The heat exchange device includes a disconnected front tail gas channel and a hot water channel. The air inlet of the front tail gas channel is fed with high-temperature flue gas. The water cooling box is provided with a disconnected cooling water channel and a rear tail gas channel. The water inlet of the cooling water channel is fed with cooling water. The water outlet of the cooling water channel is connected to the inlet of the hot water channel. The air outlet of the front tail gas channel is connected to the air inlet of the rear tail gas channel. The top of the hot water channel is connected with a steam pipe. The water in the hot water channel is heated by the high-temperature flue gas to generate water vapor. The air induced device includes an air cooling pipe and a fan. The air cooling pipe is connected to the air outlet of the rear tail gas channel of the water cooling box, and the air outlet of the fan is in the air cooling pipe. It can make the flue gas unaffected by the outside world, always stable, and will not affect the treatment of the steel wire. The high-temperature flue gas is cooled step by step, and the cooling water becomes water vapor for use in the entire steel wire production line.

[0004] Regarding the above-mentioned related technologies, the inventors believe that the following defects exist: in this solution, the utilization rate of high-temperature flue gas is still relatively low, the efficiency of steam generation in the early stage is very low, and after steam is generated, only a small part of the heat of the flue gas is utilized, and scale is very easy to generate. Summary of the invention

[0005] In order to overcome the above problems, the present application provides a device for recycling heat from exhaust gas from a heating furnace.

[0006] The heating furnace exhaust gas heat recovery device provided in the present application adopts the following technical scheme: the heating furnace exhaust gas heat recovery device includes a flue connecting pipe, a water tank, a steam generator, a duct equipment and a residual heat utilization device, the steam generator is installed on the flue connecting pipe, the duct equipment is installed on the end of the steam generator away from the flue connector, the residual heat utilization device is installed on the duct equipment, the water tank is on one side, the water tank is respectively connected to the steam generator, the duct equipment and the residual temperature utilization device, the residual temperature utilization device and the duct equipment preheat the cold water in the water tank for the steam generator to quickly generate steam.

[0007] Optionally, the steam generator includes a thin flue, of which a plurality is provided;

[0008] There are two connecting rings, which are fixed at both ends of the thin flue respectively and fix multiple thin flues at the same time;

[0009] The movable ring is located between the two connecting rings and is sleeved on the plurality of thin flues, with a gap being provided between the movable ring and the thin flues;

[0010] The sealing cover is integrally sleeved on the connecting ring and the thin flue, and its upper and lower ends are respectively sealed and fixed with the two connecting rings;

[0011] There are multiple steam pipes, all fixed at the upper end of the sealing cover, connecting the inside and outside of the sealing cover;

[0012] Insulation sleeve, the above structure is entirely in the insulation sleeve, the lower end of the insulation sleeve is connected to the flue connecting pipe, and the connection is sealed.

[0013] There are two exhaust pipes, both of which are fixed on the sealing cover and communicated with the sealing cover, and the other end passes through the insulation cover;

[0014] The water inlet pipe A is located on the movable ring. One end of the water inlet pipe A is communicated with the inside of the sealing cover, and the other end of the water inlet pipe A passes through the insulation sleeve and is communicated with the inside of the water tank.

[0015] Optionally, a circular hole is opened on the movable ring corresponding to any thin flue, the circular hole is larger than the diameter of the thin flue, the outer ring of the movable ring contacts the inner wall of the sealing cover, and a sealing ring is installed.

[0016] Optionally, the exhaust pipes are distributed up and down and are located on the upper and lower sides of the movable ring respectively.

[0017] Optionally, a cavity is provided in the inner wall of the thermal insulation sleeve, and the cavity is filled with thermal insulation cotton.

[0018] Optionally, one end of the water inlet pipe A inside the water tank is an arc-shaped structure and is tangent to the arc of the inner wall of the water tank.

[0019] Optionally, the duct equipment includes an inner duct corresponding to the upper connecting ring;

[0020] The outer duct is placed outside the inner duct, and the steam pipe corresponds to the position between the inner duct and the outer duct;

[0021] The blades are provided in plurality, are distributed at equal distances and are arranged obliquely, and are located between the inner duct and the outer duct, and are fixedly connected to the two;

[0022] The preheating cover A is sleeved outside the outer duct, and its upper and lower ends are respectively fixed to the upper and lower ends of the outer duct, and a cavity is formed between the middle and the outer duct;

[0023] A water inlet pipe B, one end of which is inserted into the water tank and extends to the bottom of the water tank, and the other end of which is fixed on the preheating cover A and communicated with the inner bottom of the preheating cover A;

[0024] One end of the drain pipe A is inserted into the water tank and extends to the upper end of the water tank, and the other end is fixed on the preheating cover A and communicated with the inner top of the preheating cover A.

[0025] Optionally, the shapes of the inner duct, the outer duct and the preheating cover A are matched to be a structure that is thin in the middle and thick at both ends, and the middle position smoothly extends and expands toward both ends.

[0026] Optionally, the residual heat utilization device includes a cold smoke pipe, which is fixed on the outer duct and is connected to the inner duct and the outer duct;

[0027] The preheating cover B is fixedly sleeved outside the cold smoke pipe, with the upper and lower ends sealed and a cavity formed in the middle;

[0028] The spiral tube is located in the cavity and is sleeved outside the cold smoke tube;

[0029] The water inlet pipe C has one end inserted into the water tank and extending to the bottom of the water tank, and the other end is fixed to the bottom of the spiral tube and communicated with the inside thereof;

[0030] One end of the drain pipe B is inserted into the water tank and extends to the upper end of the water tank, and the other end is fixed to the top of the spiral pipe and communicated with the interior thereof.

[0031] Optionally, a sealing cover is fixed to the upper end of the water tank, and a pump pipe is installed at the bottom end of the water tank.

[0032] In summary, this application includes the following beneficial technical effects:

[0033] 1. The exhaust gas heat recycling device of the heating furnace is provided with a water tank and a steam generator. The cold water in the water tank enters the sealing cover through the water inlet pipe A, and will first accumulate on the movable ring and then slowly leak down. Since the high-temperature flue gas has heated the thin flue, the cold water dripping on the thin flue will instantly evaporate into steam, and the cold water accumulated above the movable ring will gradually be preheated and then form steam, which is discharged from the two exhaust pipes for utilization. When the cold water above the movable ring boils, the position of the movable ring will be unstable due to the pressure difference between the upper and lower ends of the movable ring, thereby reducing the probability of scale formation on the thin flue, and the cold water will not be heated all at once, the efficiency of steam generation is high, and most of the heat is used in the program.

[0034] 2. The device for recycling heat from exhaust gas of the heating furnace is provided with a duct device. After the high-temperature flue gas passes through the thin flue, it is discharged from the inner duct and between the outer duct and the inner duct. Since steam is generated in the sealing cover, part of the steam forms a high-speed airflow and is ejected through the steam pipe, and corresponds to the inner duct and the outer duct, thereby increasing the flow rate of the flue gas. Due to the shapes of the inner duct and the outer duct, the high-temperature flue gas flows faster in the outer duct, and the low-temperature flue gas is discharged from the inner duct, so that the cold water inside the preheating cover A is heated and can be circulated in the water tank after heating to increase the temperature of the cold water on the upper part of the water tank, which is convenient for the use of the steam generator and the heat of the flue gas is utilized again.

[0035] 3. The exhaust heat recycling device of the heating furnace is provided with residual heat utilization equipment. When the flue gas is discharged into the cold smoke pipe, a certain temperature exists in the preheating cover B, thereby heating the cold water inside the spiral tube, and realizing the effect of circulating the cold water in the water tank again, and further preheating the cold water on the upper part of the water tank, thereby realizing the effect of high-efficiency steam generation with low waiting time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure in the embodiment of the present application;

[0037] Figure 2 is a structural cross-sectional view of an embodiment of the present application;

[0038] Figure 3 It is a structural separation diagram in an embodiment of the present application;

[0039] Figure 4 is a structural diagram of a steam generator in an embodiment of the present application;

[0040] Figure 5 is a structural diagram of a ducted device in an embodiment of the present application;

[0041] Figure 6 is a corresponding diagram of a steam generator and a ducted device in an embodiment of the present application;

[0042] Figure 7 is an internal structure diagram of a water tank in an embodiment of the present application;

[0043] Figure 8 In the embodiment of this application Figure 4 A magnified view of the structure at center A;

[0044] Fig. 9 In the embodiment of this application Figure 4 A magnified view of the structure at point B.

[0045] Figure numerals: 1. Flue connecting pipe; 2. Water tank; 3. Steam generator; 301. Thin flue; 302. Connecting ring; 303. Movable ring; 304. Sealing cover; 305. Steam pipe; 306. Insulation sleeve; 307. Exhaust pipe; 308. Water inlet pipe A; 309. Round hole; 310. Sealing ring; 4. Duct equipment; 401. Inner duct; 402. Outer duct; 403. Blade; 404. Preheating cover A; 405. Water inlet pipe B; 406. Drain pipe A; 5. Residual heat utilization equipment; 501. Cold smoke pipe; 502. Preheating cover B; 503. Spiral pipe; 504. Water inlet pipe C; 505. Drain pipe B; 6. Pump water pipe. DETAILED DESCRIPTION

[0046] The following is combined with Figure 1-9 This application is described in further detail.

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] It should be noted that all directional indications in the embodiments of the present application are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0049] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0050] In addition, in this application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0051] The present application discloses a device for recycling heat from exhaust gas from a heating furnace. Figure 1-9 As shown, it includes a flue connecting pipe 1, a water tank 2, a steam generator 3, a duct device 4 and a residual heat utilization device 5. The steam generator 3 is installed on the flue connecting pipe 1, the duct device 4 is installed on the end of the steam generator 3 away from the flue connector, the residual heat utilization device 5 is installed on the duct device 4, and the water tank 2 is on one side. The water tank 2 is respectively connected to the steam generator 3, the duct device 4 and the residual heat utilization device 5. The residual temperature utilization device 5 and the duct device 4 preheat the cold water in the water tank 2 for the steam generator 3 to quickly generate steam.

[0052] The flue connecting pipe 1 needs to be installed on the existing smoke exhaust pipe of the steel wire furnace.

[0053] The steam generator 3 includes a plurality of thin flues 301 .

[0054] There are two connecting rings 302 , which are fixed at both ends of the thin flue 301 respectively, and fix a plurality of thin flues 301 at the same time.

[0055] The movable ring 303 is located between the two connecting rings 302 and is sleeved on the plurality of thin flues 301 , with a gap being provided between the movable ring 303 and the thin flues 301 .

[0056] The sealing cover 304 is integrally sleeved on the connecting ring 302 and the thin flue 301 , and its upper and lower ends are sealed and fixed to the two connecting rings 302 respectively.

[0057] There are multiple steam pipes 305 , all of which are fixed at the upper end of the sealing cover 304 and connect the inside and outside of the sealing cover 304 .

[0058] The insulation sleeve 306, the above structure is entirely in the insulation sleeve 306, the lower end of the insulation sleeve 306 is connected to the flue connecting pipe 1, and the connection is sealed.

[0059] There are two exhaust pipes 307 , both of which are fixed on the sealing cover 304 and communicated with the sealing cover 304 , and the other end passes through the insulation sleeve 306 .

[0060] The water inlet pipe A308 is located on the movable ring 303 , one end of which is connected to the sealing cover 304 , and the other end of which passes through the insulation sleeve 306 and is connected to the water tank 2 .

[0061] The temperature utilization rate of high-temperature flue gas can be increased by providing multiple thin flues 301. Flue gas can flow in the thin flues 301, and the exhaust pipe 307 is connected to the downstream equipment to utilize the generated steam. The high-temperature steam can also be used for steel wire production.

[0062] A circular hole 309 is provided on the movable ring 303 corresponding to any thin flue 301 . The circular hole 309 is larger than the diameter of the thin flue 301 . The outer ring of the movable ring 303 contacts the inner wall of the sealing cover 304 and is provided with a sealing ring 310 .

[0063] When the cold water is above the movable ring 303, it can drip through the circular hole 309 to below the movable ring 303. The movable ring 303 can also prevent the smoking pipe from scaling.

[0064] The exhaust pipes 307 are distributed up and down and are located at the upper and lower sides of the movable ring 303 respectively.

[0065] It is used to discharge the steam generated above and below the movable ring 303, and can also achieve a pressure difference between the upper and lower parts of the movable ring 303.

[0066] The inner wall of the thermal insulation sleeve 306 is provided with a cavity, and the interior of the cavity is filled with thermal insulation cotton.

[0067] The heat-insulating sleeve 306 can prevent the heat inside the thin flue 301 from being lost.

[0068] One end of the water inlet pipe A308 inside the water tank 2 is an arc-shaped structure and is tangent to the arc of the inner wall of the water tank 2.

[0069] A water pump is installed inside the water inlet pipe A308, and the water pump is remotely driven and controlled by a control device.

[0070] The duct device 4 includes an inner duct 401 corresponding to the upper connecting ring 302 .

[0071] The outer duct 402 is sleeved outside the inner duct 401 , and the steam pipe 305 corresponds to a position between the inner duct 401 and the outer duct 402 .

[0072] There are multiple blades 403 , which are equidistantly distributed and tilted. The blades 403 are located between the inner duct 401 and the outer duct 402 , and are fixedly connected to the two.

[0073] The preheating cover A404 is sleeved outside the outer duct 402 , and its upper and lower ends are respectively fixed to the upper and lower ends of the outer duct 402 , and a cavity is formed between the middle and the outer duct 402 .

[0074] One end of the water inlet pipe B405 is inserted into the water tank 2 and extends to the bottom end of the water tank 2, and the other end is fixed on the preheating cover A404 and communicated with the inner bottom end of the preheating cover A404.

[0075] One end of the drain pipe A406 is inserted into the water tank 2 and extends to the upper end of the water tank 2, and the other end is fixed on the preheating cover A404 and communicated with the inner top of the preheating cover A404.

[0076] High-temperature flue gas mainly flows through the inner duct 401 and the outer duct 402, and the preheating cover A404 can ensure that heat is not lost. The high-speed steam discharged from the steam pipe 305 can rotate upward between the blades 403 and drive the flue gas to flow at high speed, so that the flue gas is divided into high-pressure and low-pressure parts.

[0077] The shapes of the inner duct 401, the outer duct 402 and the preheating cover A404 are coordinated to form a structure that is thin in the middle and thick at both ends, and the middle position smoothly extends and expands toward both ends.

[0078] This shape can increase the flow rate of the smoke and prevent clogging in the thin smoke channel 301.

[0079] The residual heat utilization device 5 includes a cold smoke pipe 501 , which is fixed on the outer duct 402 and is in communication with the inner duct 401 and the outer duct 402 .

[0080] The preheating cover B502 is fixedly sleeved outside the cold smoke pipe 501, with the upper and lower ends sealed to form a cavity in the middle.

[0081] The spiral tube 503 is located in the cavity and is sleeved outside the cold smoke tube 501 .

[0082] One end of the water inlet pipe C504 is inserted into the water tank 2 and extends to the bottom end of the water tank 2, and the other end is fixed to the bottom end of the spiral tube 503 and communicated with the interior thereof.

[0083] One end of the drain pipe B505 is inserted into the water tank 2 and extends to the upper end of the water tank 2, and the other end is fixed to the top of the spiral tube 503 and communicated with the interior thereof.

[0084] When the flue gas passes through the cold smoke pipe 501, its temperature is not high, so the temperature inside the preheating cover B502 can be slowly increased, and the increased heat can be transferred to the spiral tube 503, which is made of copper tube.

[0085] A sealing cover is fixed to the upper end of the water tank 2, and a pump pipe 6 is installed at the bottom end of the water tank 2.

[0086] The water pump pipe 6 needs to ensure the water volume inside the water tank 2 , and the newly pumped cold water needs to be at the bottom of the water tank 2 .

[0087] The implementation principle of the heat recycling device for exhaust gas from a heating furnace in the embodiment of the present application is as follows: the flue connecting pipe 1 is connected to the exhaust pipe of the existing steel wire preheating furnace, and the cold water in the water tank 2 is pumped into the sealing cover 304 through the water inlet pipe A308, and will first accumulate on the movable ring 303, and then slowly leak down. Since the high-temperature flue gas has heated the thin flue 301, the cold water dripping onto the thin flue 301 will instantly evaporate into steam, and the cold water accumulated above the movable ring 303 will gradually be preheated and then form steam, which is discharged from the two exhaust pipes 307 for utilization. When the cold water above the movable ring 303 boils, the position of the movable ring 303 will be unstable due to the pressure difference between the upper and lower ends of the movable ring 303, thereby reducing the probability of scale formation on the thin flue 301, and the cold water will not be heated all at once, and the efficiency of steam generation is relatively high. The high-temperature flue gas passes through the thin flue 30 1, and then discharged from the inner channel 401 and between the outer channel 402 and the inner channel 401. Since steam is generated in the sealing cover 304, part of the steam forms a high-speed airflow and is ejected through the steam pipe 305, and corresponds to the inner channel 401 and the outer channel 402, thereby increasing the flow rate of the flue gas. Due to the shapes of the inner channel 401 and the outer channel 402, the high-temperature flue gas flows faster in the outer channel 402, and the low-temperature flue gas is discharged from the inner channel 401, thereby the cold water inside the preheating cover A404 is heated, and after heating, it can be circulated in the water tank 2 to increase the temperature of the cold water on the top of the water tank 2, which is convenient for the use of the steam generator 3. When the gas is discharged into the cold smoke pipe 501, a certain temperature exists in the preheating cover B502, thereby heating the cold water inside the spiral tube 503, and once again realizing the effect of circulating the cold water in the water tank 2, further preheating the cold water on the top of the water tank 2.

[0088] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0089] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0090] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for recycling heat from exhaust gas from a heating furnace, characterized in that: The invention comprises a flue connecting pipe (1), a water tank (2), a steam generator (3), a duct device (4) and a residual heat utilization device (5), wherein the steam generator (3) is mounted on the flue connecting pipe (1), the duct device (4) is mounted on an end of the steam generator (3) away from the flue connector, the residual heat utilization device (5) is mounted on the duct device (4), the water tank (2) is located on one side, the water tank (2) is connected to the steam generator (3), the duct device (4) and the residual heat utilization device (5) respectively, and the residual heat utilization device (5) and the duct device (4) preheat the cold water in the water tank (2) for the steam generator (3) to quickly generate steam; The steam generator (3) comprises a plurality of thin flues (301); There are two connecting rings (302), which are respectively fixed at two ends of the plurality of thin flues (301); The movable ring (303) is located between the two connecting rings (302) and is sleeved on the plurality of thin flues (301), with a gap being provided between the movable ring (303) and the thin flues (301); The sealing cover (304) is integrally sleeved on the connecting ring (302) and the thin flue (301), and its upper and lower ends are respectively sealed and fixed to the two connecting rings (302); A plurality of steam pipes (305) are provided, all of which are fixed to the upper end of the sealing cover (304) and communicate with the inside and outside of the sealing cover (304); The insulation sleeve (306) is arranged outside the sealing cover (304) and the steam pipe (305), and the lower end of the insulation sleeve (306) is connected to the flue connecting pipe (1), and the connection is sealed; There are two exhaust pipes (307), both of which are fixed on the sealing cover (304) and communicate with the sealing cover (304), and the other end of which passes through the insulation sleeve (306); A water inlet pipe A (308) is located on the movable ring (303), one end of the water inlet pipe A (308) is connected to the sealing cover (304), and the other end of the water inlet pipe A (308) passes through the insulation sleeve (306) and is connected to the water tank (2); The duct equipment (4) includes an inner duct (401) corresponding to the upper connecting ring (302); The outer duct (402) is sleeved outside the inner duct (401), and the steam pipe (305) corresponds to the position between the inner duct (401) and the outer duct (402); A plurality of blades (403) are provided, which are equidistantly distributed and inclined, and the blades (403) are located between the inner duct (401) and the outer duct (402), and are fixedly connected to the two. A preheating cover A (404) is sleeved outside the outer duct (402), with its upper and lower ends respectively fixed to the upper and lower ends of the outer duct (402), and a cavity is formed between the middle and the outer duct (402); A water inlet pipe B (405), one end of which is inserted into the water tank (2) and extends to the bottom end of the water tank (2), and the other end of which is fixed on the preheating cover A (404) and communicates with the inner bottom end of the preheating cover A (404); A drainage pipe A (406), one end of which is inserted into the water tank (2) and extends to the upper end of the water tank (2), and the other end of which is fixed on the preheating cover A (404) and communicates with the inner top end of the preheating cover A (404); The shapes of the inner duct (401), the outer duct (402) and the preheating cover A (404) are coordinated to form a structure that is thin in the middle and thick at both ends, and the middle position smoothly extends and expands toward both ends; The residual heat utilization device (5) comprises a cold smoke pipe (501), which is fixed on the outer duct (402) and is in communication with the inner duct (401) and the outer duct (402); The preheating cover B (502) is fixedly sleeved outside the cold smoke pipe (501), with upper and lower ends sealed and a cavity formed in the middle; The spiral tube (503) is located in the cavity and is sleeved outside the cold smoke tube (501); A water inlet pipe C (504), one end of which is inserted into the water tank (2) and extends to the bottom end of the water tank (2), and the other end of which is fixed to the bottom end of the spiral tube (503) and communicated with the interior thereof; One end of the drainage pipe B (505) is inserted into the water tank (2) and extends to the upper end of the water tank (2), and the other end is fixed to the top end of the spiral tube (503) and communicated with the interior thereof.

2. The heating furnace tail gas heat recycling device according to claim 1, characterized in that: A circular hole (309) is provided on the movable ring (303) corresponding to any thin flue (301). The circular hole (309) is larger than the diameter of the thin flue (301). The outer ring of the movable ring (303) contacts the inner wall of the sealing cover (304) and is provided with a sealing ring (310).

3. The heating furnace tail gas heat recycling device according to claim 2, characterized in that: The exhaust pipes (307) are distributed up and down and are respectively located on the upper and lower sides of the movable ring (303).

4. The heating furnace tail gas heat recycling device according to claim 3, characterized in that: The inner wall of the thermal insulation sleeve (306) is provided with a cavity, and the interior of the cavity is filled with thermal insulation cotton.

5. The heating furnace tail gas heat recycling device according to claim 4, characterized in that: One end of the water inlet pipe A (308) located inside the water tank (2) is an arc-shaped structure and is tangent to the arc of the inner wall of the water tank (2).

6. The heating furnace tail gas heat recycling device according to claim 5, characterized in that: A sealing cover is fixed to the upper end of the water tank (2), and a pump pipe (6) is installed at the bottom end of the water tank (2).

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