A spiral double preheating heat exchanger suitable for pure oxygen combustion system

Abstract

The present application relates to a kind of spiral double preheating heat exchanger suitable for pure oxygen combustion system, including heat exchanger shell and the cleaning mechanism for cleaning the inside component of heat exchanger shell;Four layers of spiral heat exchange tubes are arranged in the inside of heat exchanger shell, and each layer of spiral heat exchange tube is uniformly distributed on a circumference from inside to outside;Multiple maintenance flushing reserved holes are opened on the outside wall of heat exchanger shell, and the position of the outside wall of heat exchanger shell is close to two ends respectively opened with high-temperature flue gas inlet and low-temperature flue gas outlet, high-temperature flue gas inlet is connected with smoke pipe, low-temperature flue gas outlet is connected by pipeline, maintenance flushing reserved hole is connected with cleaning mechanism by water pipe one, and ash removal mechanism is arranged on smoke pipe, and cleaning mechanism can drive ash removal mechanism to filter the flue gas entering the inside of heat exchanger shell and remove soot.This kind of spiral double preheating heat exchanger suitable for pure oxygen combustion system makes the flame type and combustion condition of subsequent combustion more stable.

Description

Technical Field

[0001] This invention patent relates to a spiral double preheating heat exchanger suitable for pure oxygen combustion systems, mainly used for flue gas heat exchange and waste heat recovery in pure oxygen combustion systems in the petrochemical and metallurgical industries. It can also be used for flue gas heat exchange and waste heat recovery in ordinary combustion systems. Background Technology

[0002] Currently, combustion systems are widely used in industries such as petrochemicals and metallurgy. After fuel is burned in a boiler, the resulting flue gas contains a large amount of unused waste heat. Using a heat exchanger can recover the waste heat from the flue gas, achieving higher energy conversion efficiency and realizing the goal of energy conservation and emission reduction.

[0003] With the continuous advancement of combustion technology, pure oxygen combustion, with its cleaner characteristics, will gradually become more widespread. Compared to conventional combustion, pure oxygen combustion produces almost no nitrogen oxides and sulfur oxides, and the amount of flue gas generated is also significantly reduced. Pure oxygen combustion can achieve more efficient and environmentally friendly combustion.

[0004] The theoretical maximum flame temperature of pure oxygen combustion can reach 2700 degrees Celsius, and the flue gas temperature can reach 950 degrees Celsius without refractory lining the furnace walls. Compared to traditional heat exchangers, the problem of flue gas recovery from pure oxygen combustion places higher demands on its heat exchange efficiency.

[0005] Most current flue gas heat exchangers can only exchange heat between two gases, that is, heat the gas. However, heating the gas and oxygen at the same time will make the combustion more stable and complete.

[0006] The undepleted oxygen in the flue gas will scour and oxidize the internal pipes of the heat exchanger, affecting the performance and lifespan of the heat exchanger. Currently, most spiral wound heat exchangers do not have a solution for internal cleaning.

[0007] In a pure oxygen combustion system, the combustion process requires real-time monitoring and dynamic adjustment. This necessitates changes and fluctuations in pressure and flow in the main oxygen and gas pipelines. These fluctuations, along with system startup and shutdown, cause fluid impact on the 3-spiral heat exchange tubes. Failure to control this hazard over time can lead to metal fatigue in the internal structure, shortening the equipment's lifespan.

[0008] To address the above problems, a spiral double preheating heat exchanger suitable for pure oxygen combustion systems has been invented. Summary of the Invention

[0009] The purpose of this invention is to provide a spiral double preheating heat exchanger suitable for pure oxygen combustion systems, thereby solving the problems mentioned in the background art. To achieve the above objective, this invention provides the following technical solution: a spiral double preheating heat exchanger suitable for pure oxygen combustion systems, comprising a heat exchanger outer shell, and further comprising:

[0010] Cleaning mechanism for cleaning internal components of heat exchanger housing;

[0011] The heat exchanger shell is provided with four layers of spiral heat exchange tubes inside, and each layer of spiral heat exchange tubes is evenly distributed on a circumference from the inside to the outside.

[0012] The outer wall of the heat exchanger shell is provided with multiple maintenance and flushing holes. The outer wall of the heat exchanger shell is provided with a high-temperature flue gas inlet and a low-temperature flue gas outlet near both ends. The high-temperature flue gas inlet is connected to the flue gas inlet pipe, and the low-temperature flue gas outlet is connected through a pipeline. The maintenance and flushing holes are connected to the cleaning mechanism through a water pipe. The flue gas inlet pipe is equipped with an ash removal mechanism, and the cleaning mechanism can drive the ash removal mechanism to filter and remove dust from the flue gas entering the heat exchanger shell.

[0013] Preferably, the four-layer spiral heat exchange tubes are arranged from the inside out as follows: the first layer has four tubes, the second layer has six tubes, the third layer has six tubes, and the fourth layer has eight tubes. The spiral length of the tubes increases sequentially from the inside out, so that the four-layer spiral heat exchange tubes form a vortex structure in the cavity, so that the flue gas can pass through the gaps between the tubes. Furthermore, from the inside out, the spiral lines of the first and third layers are arranged counterclockwise, as are the spiral lines of the second and fourth layers.

[0014] Preferably, both ends of the heat exchanger shell are fixed with spiral tube fixing plates, and the two ends of the spiral heat exchange tube pass through and are welded to the corresponding spiral tube fixing plates.

[0015] Preferably, a gas separation shell is provided on the side of the spiral tube fixing clamp away from the heat exchanger outer shell, and the end of the spiral heat exchange tube is connected to the corresponding gas separation shell. The gas separation shell is fixedly connected to the corresponding spiral tube fixing clamp and the heat exchanger outer shell port through flanges and multiple bolt assemblies. Sealing rings are provided on the end faces of the bolt assembly connections to prevent gas leakage, ensure economic efficiency and prevent safety accidents.

[0016] Preferably, a baffle plate is fixed inside the gas separation shell, and the baffle plate divides the gas separation shell into an oxygen fluid domain and a gas combustion fluid domain. A low-temperature oxygen inlet duct and a low-temperature gas combustion inlet duct are fixedly connected to the gas separation shell near the low-temperature flue gas outlet, and the low-temperature oxygen inlet duct is connected to the oxygen fluid domain and the low-temperature gas combustion inlet duct is connected to the gas combustion fluid domain. A high-temperature oxygen outlet duct and a high-temperature gas combustion outlet duct are fixedly connected to the gas separation shell near the high-temperature flue gas inlet, and the high-temperature oxygen outlet duct is connected to the oxygen fluid domain and the high-temperature gas combustion outlet duct is connected to the gas combustion fluid domain.

[0017] Preferably, both the low-temperature oxygen intake duct and the low-temperature gas intake duct are equipped with spring-type energy storage devices, which can reduce the vibration of the spiral heat exchange tube caused by fluid impact due to pressure and flow adjustment.

[0018] Preferably, the plurality of maintenance flushing reserved holes are evenly distributed on the outer side wall of the heat exchanger shell. The cleaning mechanism includes a clean water tank, on which a pump impeller and a frame plate are fixed. A water pipe is fixed to and connected to the side wall of the pump impeller. A slide rail is fixed on the frame plate, and a slide block is slidably connected to the slide rail. A motor is fixed on the slide block. A gear two is coaxially fixed to the output shaft of the motor. A gear three is coaxially fixed to the impeller shaft of the pump impeller, and gear two can mesh with gear three.

[0019] Preferably, the low-temperature flue gas outlet is connected to the inlet end of the tee connector, and the two outlet ends of the tee connector are respectively connected to the flue pipe and the sewage pipe. The end of the tee connector near the flue pipe is connected to solenoid valve one, and the end of the tee connector near the sewage pipe is connected to solenoid valve two. A filter cylinder is fixed inside the clean water tank, and the sewage pipe is connected to the inside of the filter cylinder. A water pipe two is connected to the bottom plate of the clean water tank. The end of the impeller shaft of the pump water wheel away from gear three passes through the top wall of the clean water tank and is located inside the filter cylinder. A scraper is fixed to the end of the impeller shaft located inside the filter cylinder.

[0020] Preferably, a second bracket is fixed on the frame plate, and a cylinder is fixed on the second bracket. The piston rod end of the cylinder is fixedly connected to a connecting rod, and the upper and lower ends of the connecting rod are respectively fixedly connected to a rack and a slide block. The rack and the slide rail are arranged parallel to each other. A butterfly valve is connected to the smoke inlet pipe, and the valve stem of the butterfly valve is coaxially fixedly connected to a gear, which meshes with the rack.

[0021] Preferably, the ash removal mechanism includes a filter screen fixed on the inner wall of the flue, the filter screen being inclined and the impact surface of the filter screen with the flue gas facing downwards, an ash discharge cylinder fixed on the outer wall of the flue, the ash discharge cylinder being connected to the side of the filter screen inside the flue that impacts the flue gas, a plug fixed at the end of the rack, and the plug being able to seal the outlet end of the ash discharge cylinder, a bracket fixed on the frame plate, and a gear plate rotatably connected to the bracket plate, a gear two being able to mesh with the gear plate, a pin fixed on the gear plate at a position away from the center, a sliding sleeve penetrating and fixedly connected to the side wall of the ash discharge cylinder, a sliding rod inserted and slidably connected inside the sliding sleeve, a hammer head and a sliding frame respectively connected to the upper and lower ends of the sliding rod, the hammer head being used to hammer the side of the filter screen that impacts the flue gas, shaking off the dust adhering to it, and the pin being inserted and slidably connected to the sliding frame.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1) The fuel and oxygen are preheated in two ways, which makes the flame pattern and combustion conditions of the subsequent combustion more stable. In addition, the dust in the flue gas is filtered in real time when the high-temperature flue gas is transported for heat exchange, thereby reducing the deposits on the spiral heat exchange tube wall and improving its heat exchange efficiency and service life.

[0024] 2) It is equipped with a maintenance flushing hole. During the later maintenance and repair process, the deposits and oxides on the surface of the internal spiral heat exchange tube can be flushed through the maintenance flushing hole. If flushing is not performed regularly, the deposits and oxides on the spiral tube wall will affect its heat exchange performance. It reduces the difficulty of maintenance and cleaning. In addition, it can purify the water while cleaning the spiral heat exchange tube, so that the water can be purified and recycled, saving water.

[0025] 3) In view of the characteristics of pure oxygen combustion, low flue gas volume and high temperature, a spiral double preheating heat exchanger suitable for pure oxygen combustion system adopts a coiled tube structure, which can adapt to high load gas heat transfer.

[0026] 4) Install spring-type energy storage devices in the low-temperature oxygen intake duct and the low-temperature gas intake duct. The spring-type energy storage devices can effectively reduce the peak value of hydraulic shock, reduce the vibration of the spiral heat exchange tube caused by fluid shock due to pressure and flow adjustment, and can also serve as a buffer device for sudden pressure drop, so that the pressure drops smoothly. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall assembly cross-section of the present invention;

[0028] Figure 2 This is a schematic diagram of the heat exchanger outer shell structure in this invention;

[0029] Figure 3 for Figure 1Enlarged structural diagram at point A in the diagram;

[0030] Figure 4 for Figure 1 Enlarged structural diagram at point B in the diagram;

[0031] Figure 5 This is a schematic diagram of the air inlet structure of the heat exchanger housing in this invention;

[0032] Figure 6 This is a schematic cross-sectional view of the gas separation shell structure in this invention.

[0033] In the diagram: 1. Heat exchanger outer shell; 2. Inspection and flushing pre-drilled hole; 3. Spiral heat exchange tube; 4. Spiral tube fixing clamp; 5. Baffle plate; 6. Gas separation shell; 7. Spring-type accumulator; 8. Low-temperature oxygen inlet duct; 9. Low-temperature gas inlet duct; 10. High-temperature oxygen outlet duct; 11. High-temperature gas outlet duct; 12. High-temperature flue gas inlet; 13. Low-temperature flue gas outlet; 14. Sealing ring; 15. T-joint; 16. Solenoid valve one; 17. Solenoid valve two; 18. Exhaust pipe; 19. Sewage pipe; 20. Water pipe one 21. Smoke inlet pipe; 22. Butterfly valve; 23. Filter screen; 24. Ash discharge cylinder; 25. Slide rod; 26. Support 1; 27. Support 2; 28. Cylinder; 29. ​​Gear 1; 30. Rack; 31. Pump impeller; 32. Clean water tank; 33. Filter cartridge; 34. Scraper; 35. Water pipe 2; 36. Hammer; 37. Sliding sleeve; 38. Slide frame; 39. Pin; 40. Gear disc; 41. Connecting rod; 42. Frame plate; 43. Slide rail; 44. Slide seat; 45. Gear 2; 46. Motor; 47. Gear 3; 48. Plug. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figures 1 to 6 The present invention provides a technical solution: a spiral double preheating heat exchanger suitable for a pure oxygen combustion system, comprising a heat exchanger outer shell 1, and further comprising:

[0036] A cleaning mechanism for cleaning the internal components of the heat exchanger housing 1;

[0037] The heat exchanger outer shell 1 is equipped with four layers of spiral heat exchange tubes 3, and each layer of spiral heat exchange tubes 3 is evenly distributed on a circumference from the inside to the outside. The four layers of spiral heat exchange tubes 3 have four tubes in the first layer, six tubes in the second layer, six tubes in the third layer, and eight tubes in the fourth layer. The spiral length of the tubes increases from the inside to the outside, so that the four layers of spiral heat exchange tubes 3 form a vortex structure in the cavity, so that the flue gas can pass through the gaps between the tubes. Furthermore, the spiral lines of the first and third layers of spiral heat exchange tubes 3 are arranged counterclockwise from the inside to the outside, and the spiral lines of the second and fourth layers are arranged counterclockwise. The spiral directions of adjacent layers are opposite, which helps the flue gas flow.

[0038] Multiple maintenance and flushing pre-reserved holes 2 are provided on the outer side wall of the heat exchanger shell 1. These holes 2 are evenly distributed on the outer side wall of the heat exchanger shell 1. High-temperature flue gas inlet 12 and low-temperature flue gas outlet 13 are respectively provided near both ends of the outer side wall of the heat exchanger shell 1. The high-temperature flue gas inlet 12 is connected to the flue gas inlet pipe 21, and the low-temperature flue gas outlet 13 is connected by a pipeline. The maintenance and flushing pre-reserved holes 2 are connected to the cleaning mechanism through water pipe 20. The flue gas inlet pipe 21 is equipped with an ash removal mechanism, and the cleaning mechanism can drive the ash removal mechanism to filter and remove dust from the flue gas entering the heat exchanger shell 1. During shutdown maintenance or subsequent maintenance, the attachments and oxides on the surface of the spiral heat exchange tube 3 can be flushed through the maintenance and flushing pre-reserved holes 2. If flushing is not performed regularly, the attachments and oxides on the tube wall of the spiral heat exchange tube 3 will affect its heat exchange performance.

[0039] In this embodiment, spiral tube fixing plates 4 are fixed to both ends of the heat exchanger outer shell 1, and the two ends of the spiral heat exchange tube 3 are respectively passed through and welded to the corresponding spiral tube fixing plates 4. A gas separation shell 6 is provided on the side of the spiral tube fixing plate 4 away from the heat exchanger outer shell 1, and the end of the spiral heat exchange tube 3 is connected to the interior of the corresponding gas separation shell 6. The gas separation shell 6 is fixedly connected to the corresponding spiral tube fixing plate 4 and the ends of the heat exchanger outer shell 1 through flanges and multiple bolt assemblies. Sealing rings 14 are provided on the end faces of the bolt assembly connections to prevent gas leakage, ensure economic efficiency and prevent safety accidents.

[0040] In this embodiment, a baffle plate 5 is fixed inside the gas separation shell 6, and the baffle plate 5 divides the gas separation shell 6 into an oxygen fluid domain and a gas combustion fluid domain. A low-temperature oxygen inlet duct 8 and a low-temperature gas combustion inlet duct 9 are fixedly connected to the gas separation shell 6 near the low-temperature flue gas outlet 13, and the low-temperature oxygen inlet duct 8 is connected to the oxygen fluid domain, and the low-temperature gas combustion inlet duct 9 is connected to the gas combustion fluid domain. A high-temperature oxygen outlet duct 10 and a high-temperature gas combustion outlet duct 11 are fixedly connected to the gas separation shell 6 near the high-temperature flue gas inlet 12, and the high-temperature oxygen outlet duct 10 is connected to the oxygen fluid domain, and the high-temperature gas combustion outlet duct 11 is connected to the gas combustion fluid domain.

[0041] In this embodiment, spring-type energy storage devices 7 are provided on both the low-temperature oxygen intake duct 8 and the low-temperature gas intake duct 9. These devices can reduce the vibration of the spiral heat exchange tube 3 caused by fluid impact due to pressure and flow rate adjustments. The spring-type energy storage devices 7 are installed on the low-temperature oxygen intake duct 8 and the low-temperature gas intake duct 9 with their heads facing downwards and installed vertically.

[0042] In this embodiment, the cleaning mechanism includes a clean water tank 32, on which a water pump impeller 31 and a frame plate 42 are fixed. A water pipe 20 is fixed to and connected to the side wall of the water pump impeller 31. A slide rail 43 is fixed to the frame plate 42, and a slide seat 44 is slidably connected to the slide rail 43. A motor 46 is fixed to the slide seat 44. A gear 45 is coaxially fixed to the output shaft of the motor 46. A gear 47 is coaxially fixed to the impeller shaft of the water pump impeller 31, and the gear 45 can mesh with the gear 47. The low-temperature flue gas outlet 13 is connected to the inlet end of a three-way connector 15, and the two outlet ends of the three-way connector 15 are respectively connected to the exhaust pipe 18 and the sewage pipe 19. The end of the three-way connector 15 near the exhaust pipe 18 is connected to a solenoid valve 16, and the end of the three-way connector 15 near the sewage pipe 19 is connected to... A solenoid valve 17 is connected to a filter cylinder 33 fixed inside the water tank 32. The drain pipe 19 is connected to the inside of the filter cylinder 33. The bottom plate of the water tank 32 is connected to a water pipe 35. The end of the impeller shaft of the pump wheel 31 away from the gear 47 passes through the top wall of the water tank 32 and is located inside the filter cylinder 33. The end of the impeller shaft located inside the filter cylinder 33 is fixed to a scraper 34. A bracket 27 is fixed on the frame plate 42, and a cylinder 28 is fixed on the bracket 27. The piston rod end of the cylinder 28 is fixedly connected to the connecting rod 41. The upper and lower ends of the connecting rod 41 are respectively fixedly connected to the rack 30 and the slide 44. The rack 30 and the slide rail 43 are arranged parallel to each other. A butterfly valve 22 is connected to the flue pipe 21. The valve stem of the butterfly valve 22 is coaxially fixedly connected to the gear 29. The gear 29 meshes with the rack 30.

[0043] In this embodiment, the ash removal mechanism includes a fine filter screen 23 fixed on the inner wall of the flue pipe 21. The fine filter screen 23 is inclined and the impact surface of the fine filter screen 23 with the flue gas is downward. An ash discharge cylinder 24 is fixed on the outer wall of the flue pipe 21. The ash discharge cylinder 24 is connected to the side of the fine filter screen 23 inside the flue pipe 21 that impacts the flue gas. A plug 48 is fixed to the end of the rack 30, and the plug 48 can seal the outlet end of the ash discharge cylinder 24. A bracket 26 is fixed on the frame plate 42. A gear 40 is rotatably connected to the upper fixed shaft, and a gear 45 can mesh with the gear 40. A pin 39 is fixed on the gear 40 away from the center. A sliding sleeve 37 is connected through and fixed to the side wall of the ash discharge cylinder 24. A sliding rod 25 is inserted into and slidably connected to the sliding sleeve 37. The upper and lower ends of the sliding rod 25 are respectively connected to a hammer 36 and a slide frame 38. The hammer 36 is used to hammer the side of the filter mesh 23 that impacts the flue gas, shaking off the dust adhering to it. The pin 39 is inserted into and slidably connected to the slide frame 38.

[0044] Working principle and advantages of this invention: The spiral double preheating heat exchanger suitable for pure oxygen combustion systems operates as follows:

[0045] When the pure oxygen combustion system is running, cylinder 28 pushes slide 44 and rack 30 via connecting rod 41. Figure 1 The middle moves to the left, causing the plug 48 to block the ash discharge cylinder 24. At the same time, the rack 30 drives the butterfly valve 22 to open through the gear 29. At this time, the solenoid valve 16 is in the open state, and the solenoid valve 27 is in the closed state. The high-temperature flue gas will enter the heat exchanger shell 1 from the flue pipe 21 and the high-temperature flue gas inlet. After passing through the gap between the outer wall of the spiral heat exchange tube 3 and the inner wall of the heat exchanger shell 1, it will finally enter the three-way connector 15 from the low-temperature flue gas outlet 13, and then flow out from the exhaust pipe 18 for carbon dioxide enrichment or storage. The high-temperature flue gas transfers heat to the spiral heat exchange tube 3 through convection heat exchange in the heat exchanger shell 1. The spiral heat exchange tube 3 has a large heat exchange area and high heat exchange efficiency. The unheated oxygen and fuel enter from the low-temperature oxygen inlet duct 8 and the low-temperature fuel inlet duct 9, respectively. The oxygen first passes through the gas separation shell 6. Figure 6 The gas first passes through the oxygen fluid domain in the gas separation shell 6, then through the interior of the partial spiral heat exchange tube 3, and then through the oxygen fluid domain in the gas separation shell 6 at the other end, finally exiting from the high-temperature oxygen outlet duct 10. The gas first passes through the gas separation shell 6. Figure 6 The gas flows through the gas fluid domain in the spiral heat exchange tube 3, and then through the gas fluid domain in the gas separation shell 6 at the other end, and finally is discharged from the high-temperature gas outlet duct 11. This achieves double preheating of gas and oxygen, and the fuel and oxidant are at the same temperature, which greatly helps the shape of the subsequent combustion flame and the combustion situation.

[0046] When a pure oxygen combustion system is working, in order to achieve precise combustion control and realize economic and environmental goals, it is necessary to adjust the pressure and flow rate in the main oxygen and gas pipelines in real time. Even if these adjustments are minute and smooth, the resulting fluid impact will damage the spiral heat exchanger tube 3 and greatly shorten its service life. Moreover, these fluid impacts with uncertain frequencies may be the same as the natural frequency of the mechanical vibration of the spiral heat exchanger tube 3, causing resonance. Therefore, spring-type energy storage devices 7 are installed at the inlet of the low-temperature oxygen intake duct 8 and the low-temperature gas intake duct 9. When the pressure rises, the internal pressure of the spring-type energy storage device 7 increases, the spring is compressed, and the internal volume increases. When the pressure drops, the internal pressure of the spring-type energy storage device decreases, the spring extends, and the internal volume decreases. With each action of the spring-type energy storage device 7, the pressure in the spiral heat exchanger tube 3 will change more smoothly. When the system is started, it can also ensure that the sudden pressure rise will not impact the spiral heat exchanger tube 3.

[0047] As described above, while the plug 48 is sealing the ash discharge cylinder 24, the gear 45 meshes with the gear disc 40, and the motor 46 operates synchronously with the system. The gear 45 drives the gear disc 40 to rotate, causing the gear disc 40 to move the slide 38 back and forth via the pin 39. This causes the slide 38 to drive the hammer 36 to strike the filter mesh 23 via the slide rod 25, causing it to vibrate. When the high-temperature flue gas passes through the filter mesh 23, it filters out the dust, thereby reducing the deposits on the spiral heat exchange tube 3, improving its heat exchange efficiency and service life. Furthermore, the dust adhering to the filter mesh 23 is shaken off by the hammering action of the hammer 36 and collected in the ash discharge cylinder 24 for centralized cleaning during maintenance. This achieves real-time filtration of dust in the flue gas during high-temperature flue gas heat exchange.

[0048] When the surface of the spiral heat exchanger tube 3 needs to be cleaned, the piston rod of the cylinder 28 is retracted, causing the connecting rod 41 to drive the slide 44 and the rack 30. Figure 4The slide block 44 moves to the right, causing the motor 46 to move to the right. When gear 2 45 meshes with gear 3 47, the rack 30 drives the butterfly valve 22 to close via gear 1 29, and the plug 48 moves away from the ash discharge cylinder 24 to clean out the dust in the ash discharge cylinder 24. At the same time, solenoid valve 1 16 is closed, and solenoid valve 2 17 is open. The motor 46 drives the pump impeller 31 to work via gear 2 45 and gear 3 47, so that the pump impeller 31 delivers high-speed water flow to each maintenance flushing reserved hole 2 through water pipe 1 20, and uses the water flow to clean the surface of the spiral heat exchange tube 3, removing the deposits and oxides on the tube wall. After removing impurities, the water flows through the low-temperature flue gas outlet 13 into the three-way connector 15 and then into the filter cylinder 33 through the drain pipe 19. The filter cylinder 33 traps impurities in the water, thus purifying and recycling the water, saving water. The purified water is discharged through the second water pipe 35. When the pump impeller 31 is working, its impeller shaft drives the scraper 34 to scrape and clean the dirt adhering to the inner wall of the filter cylinder 33 in real time, thereby maintaining the high-efficiency filtration effect of the filter cylinder 33 and purifying the water while cleaning the spiral heat exchange tube 3.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0050] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A spiral double preheating heat exchanger suitable for pure oxygen combustion systems, comprising a heat exchanger outer shell (1), characterized in that: Also includes: A cleaning mechanism for cleaning the internal components of the heat exchanger housing (1); The heat exchanger outer shell (1) is provided with four layers of spiral heat exchange tubes (3), and each layer of spiral heat exchange tubes (3) is evenly distributed on a circumference from the inside to the outside; The outer wall of the heat exchanger housing (1) is provided with multiple maintenance and flushing reserved holes (2), and the outer wall of the heat exchanger housing (1) is provided with a high-temperature flue gas inlet (12) and a low-temperature flue gas outlet (13) near both ends. The high-temperature flue gas inlet (12) is connected to the flue gas inlet pipe (21), and the low-temperature flue gas outlet (13) is connected through a pipeline. The maintenance and flushing reserved holes (2) are connected to the cleaning mechanism through a water pipe (20). The flue gas inlet pipe (21) is provided with an ash removal mechanism, and the cleaning mechanism can drive the ash removal mechanism to filter and remove dust from the flue gas entering the heat exchanger housing (1). Multiple maintenance flushing reserved holes (2) are evenly distributed on the outer side wall of the heat exchanger shell (1). The cleaning mechanism includes a clean water tank (32), a pump impeller (31) and a frame plate (42) are fixed on the clean water tank (32), a water pipe (20) is fixed and connected to the side wall of the pump impeller (31), a slide rail (43) is fixed on the frame plate (42), and a slide seat (44) is slidably connected on the slide rail (43). A motor (46) is fixed on the slide seat (44), a gear two (45) is coaxially fixedly connected on the output shaft of the motor (46), and a gear three (47) is coaxially fixedly connected on the impeller shaft of the pump impeller (31), and the gear two (45) can mesh with the gear three (47). The low-temperature flue gas outlet (13) is connected to the inlet end of the three-way connector (15), and the two outlet ends of the three-way connector (15) are respectively connected to the exhaust pipe (18) and the sewage pipe (19). The end of the three-way connector (15) near the exhaust pipe (18) is connected to the first solenoid valve (16), and the end of the three-way connector (15) near the sewage pipe (19) is connected to the second solenoid valve (17). The water tank (32) has a filter cylinder (33) fixed inside. The sewage pipe (19) is connected to the inside of the filter cylinder (33). The bottom plate of the water tank (32) is connected to the second water pipe (35). The impeller shaft of the pump wheel (31) away from the gear three (47) passes through the water tank. The top wall of (32) is located inside the filter cylinder (33). The impeller shaft is fixed with a scraper (34) at one end inside the filter cylinder (33). A bracket (27) is fixed on the frame plate (42), and a cylinder (28) is fixed on the bracket (27). The piston rod end of the cylinder (28) is fixedly connected to the connecting rod (41). The upper and lower ends of the connecting rod (41) are respectively fixedly connected to the rack (30) and the slide (44). The rack (30) and the slide rail (43) are arranged parallel to each other. A butterfly valve (22) is connected to the smoke inlet pipe (21). The valve stem of the butterfly valve (22) is coaxially fixedly connected to the gear (29). The gear (29) meshes with the rack (30). The ash removal mechanism includes a filter screen (23) fixed on the inner wall of the flue (21). The filter screen (23) is inclined and the impact surface of the filter screen (23) with the flue gas is downward. An ash discharge cylinder (24) is fixed on the outer wall of the flue (21). The ash discharge cylinder (24) is connected to the side of the filter screen (23) inside the flue (21) that impacts the flue gas. A plug (48) is fixed at the end of the rack (30), and the plug (48) can seal the outlet end of the ash discharge cylinder (24). A bracket (26) is fixed on the frame plate (42), and a fixed axis rotates on the bracket (26). A gear plate (40) is dynamically connected, and the gear two (45) can mesh with the gear plate (40). A pin (39) is fixed on the gear plate (40) away from the center. A sliding sleeve (37) is connected through and fixed to the side wall of the ash discharge cylinder (24). A sliding rod (25) is inserted and slidably connected inside the sliding sleeve (37). The upper and lower ends of the sliding rod (25) are respectively connected to a hammer (36) and a slide frame (38). The hammer (36) is used to hammer the side of the filter mesh (23) that impacts the flue gas, shaking off the dust adhering to it. The pin (39) is inserted and slidably connected to the slide frame (38).

2. The spiral double preheating heat exchanger suitable for a pure oxygen combustion system according to claim 1, characterized in that: The four-layer spiral heat exchange tubes (3) have four tubes arranged in the first layer, six tubes in the second layer, six tubes in the third layer, and eight tubes in the fourth layer from the inside out. The spiral length of the tubes increases from the inside out, so that the four-layer spiral heat exchange tubes (3) form a vortex structure in the cavity, so that the flue gas can pass through the gaps between the tubes. Furthermore, the spiral lines of the first and third layers of the four-layer spiral heat exchange tubes (3) are arranged counterclockwise from the inside out, and the spiral lines of the second and fourth layers are arranged counterclockwise.

3. A spiral double preheating heat exchanger suitable for a pure oxygen combustion system according to claim 1, characterized in that: Both ends of the heat exchanger outer shell (1) are fixed with spiral tube fixing plates (4), and the two ends of the spiral heat exchange tube (3) are respectively passed through and welded to the corresponding spiral tube fixing plates (4).

4. A spiral double preheating heat exchanger suitable for a pure oxygen combustion system according to claim 3, characterized in that: A gas separation shell (6) is provided on the side of the spiral tube fixing clamp (4) away from the heat exchanger outer shell (1), and the end of the spiral heat exchange tube (3) is connected to the interior of the corresponding gas separation shell (6). The gas separation shell (6) is fixedly connected to the corresponding spiral tube fixing clamp (4) and the port of the heat exchanger outer shell (1) through flanges and multiple bolt assemblies. A sealing ring (14) is provided on the end face of the bolt assembly connection to prevent gas leakage, ensure economic efficiency and prevent safety accidents.

5. A spiral double preheating heat exchanger suitable for a pure oxygen combustion system according to claim 4, characterized in that: The gas separation shell (6) is fixed with a baffle plate (5), which divides the gas separation shell (6) into an oxygen fluid domain and a gas fluid domain. The gas separation shell (6) near the low-temperature flue gas outlet (13) is fixedly connected with a low-temperature oxygen inlet duct (8) and a low-temperature gas inlet duct (9), and the low-temperature oxygen inlet duct (8) is connected to the oxygen fluid domain, and the low-temperature gas inlet duct (9) is connected to the gas fluid domain. The gas separation shell (6) near the high-temperature flue gas inlet (12) is fixedly connected with a high-temperature oxygen outlet duct (10) and a high-temperature gas outlet duct (11), and the high-temperature oxygen outlet duct (10) is connected to the oxygen fluid domain, and the high-temperature gas outlet duct (11) is connected to the gas fluid domain.

6. A spiral double preheating heat exchanger suitable for a pure oxygen combustion system according to claim 5, characterized in that: Both the low-temperature oxygen intake duct (8) and the low-temperature gas intake duct (9) are equipped with spring-type energy storage devices (7), which can reduce the vibration of the spiral heat exchange tube (3) caused by fluid impact due to pressure and flow adjustment.

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