Micro-cyclonic flue gas waste heat utilization device

Abstract

The present invention provides a micro-vortex flue gas waste heat utilization device, the device includes a heat exchanger, the heat exchanger includes a heat absorption section and a heat release section, the heat absorption section is installed at the tail end of the flue, the flue gas passes through the heat absorption section and heats the medium in the heat absorption section before being discharged; the heat release section is installed in the air duct, the air entering the boiler through the air duct passes through the heat release section; the medium enters the heat release section after being heated by the flue gas and heats the air, the medium that has completed heat release in the heat release section flows back to the heat absorption section; the medium can form a micro-vortex when flowing in the tube cavity of the heat absorption section and the heat release section. The waste heat of the flue gas is recovered by using the micro-vortex flue gas waste heat utilization technology, the outlet exhaust temperature of the boiler flue is reduced, and the recovered waste heat is used to heat the air, the fuel consumption per unit output is reduced, and the safe and economical operation of the heating surface at the tail end of the boiler is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of energy conservation and environmental protection, and in particular to a micro-cyclonic flue gas waste heat utilization device. Background Art

[0002] Since the flue gas discharged during the operation of the boiler contains sulfur components to varying degrees, sulfur and other components in the flue gas will form sulfuric acid, which will cause low-temperature acid corrosion on the air preheater or heat exchanger heating surface of the boiler, causing corrosion, leakage, ash accumulation and blockage of the heating surface of the boiler air preheater or heat exchanger, directly affecting the thermal efficiency of the boiler and the safe operation of the boiler. Direct discharge of flue gas into the atmosphere will lead to high outlet flue gas temperature, heavy load on the heating surface at the rear of the boiler, and the inability to utilize the waste heat of the flue gas. In the context of the country's strong promotion of pollution control and the development of energy-saving and environmental protection industries, energy conservation and emission reduction are also the primary task of every enterprise, which requires a device that can efficiently and safely utilize the waste heat of boiler flue gas. Summary of the invention

[0003] The purpose of the present invention is to provide a micro-cyclone flue gas waste heat utilization device, which adopts the micro-cyclone flue gas waste heat utilization technology to recover the waste heat of the flue gas, reduce the outlet exhaust temperature of the tail heat exchanger, and use the recovered waste heat to heat the air entering the boiler, thereby reducing the fuel consumption per unit output and further improving the safe and economical operation of the boiler tail heating surface. Due to the use of micro-cyclone technology, the heat exchange equipment is more efficient and the heat exchange area of ​​the equipment is also reduced.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A micro-vortex flue gas waste heat utilization device, the device can utilize the waste heat of the flue gas in the boiler flue to heat the air entering the boiler, the device comprises a heat exchanger, the heat exchanger comprises a heat absorption section and a heat release section, the height of the heat release section is higher than the height of the heat absorption section, and the outer peripheries of the tube cavities of the heat absorption section and the heat release section are both provided with annular fins; the heat absorption section is installed at the tail end of the flue, and the flue gas passes through the heat absorption section and heats the medium in the heat absorption section before being discharged; the heat release section is installed in the air duct, and the air entering the boiler through the air duct passes through the heat release section; the medium enters the heat release section after being heated by the flue gas and heats the air, and the medium that has completed heat release in the heat release section flows back to the heat absorption section; the medium can form a micro-vortex when flowing in the tube cavities of the heat absorption section and the heat release section.

[0006] Furthermore, in the above-mentioned device, the device also includes a saturated steam connecting pipe and a condensed water self-return pipe, the medium after being heated by the flue gas enters the heat release section through the saturated steam connecting pipe, and the medium that has completed heat release in the heat release section returns to the heat absorption section through the condensed water self-return pipe; a first gate valve is arranged on the saturated steam connecting pipe, and a safety valve is connected to the first gate valve; the medium is water.

[0007] Furthermore, in the above-mentioned device, the heat absorption section and the heat release section are both composed of a plurality of vertically parallel and spaced heat exchange units, the heat exchange units in the heat absorption section are arranged perpendicularly to the direction of flue gas flow, and the heat exchange units in the heat release section are arranged perpendicularly to the direction of air flow.

[0008] Further, in the above device, the heat exchange unit includes an upper main pipe bundle, a lower main pipe bundle and a plurality of branch pipe bundles connecting the upper main pipe bundle and the lower main pipe bundle, the upper main pipe bundles of the plurality of heat exchange units in the heat absorption section are connected to one end of the saturated steam connecting pipe through a first header pipe, and the upper main pipe bundles of the plurality of heat exchange units in the heat release section are connected to the other end of the saturated steam connecting pipe through a second header pipe;

[0009] The lower main pipe bundles of the plurality of heat exchange units in the heat absorption section are all connected to one end of the condensed water self-return pipe through the third header pipe, and the lower main pipe bundles of the plurality of heat exchange units in the heat release section are all connected to the other end of the condensed water self-return pipe through the fourth header pipe;

[0010] In the tube cavities of the heat absorption section and the heat release section, the branch tube bundle is sleeved with a liner perforated tube, the two ends of the liner perforated tube are welded to the two ends of the branch tube bundle, and the tube wall of the liner perforated tube is covered with through holes, which are arranged in a rotational manner;

[0011] A plurality of annular fins are sleeved in sequence on the outer periphery of each branch tube bundle along the length direction of the branch tube bundle, and a plurality of grooves extending from the outer surface are arranged on the annular fin.

[0012] Furthermore, in the above-mentioned device, the outer diameter of the branch pipe bundle is 38 mm; the outer diameter of the lining perforated pipe is 32 mm, the diameter of the through hole is 14 mm or 16 mm, and the through holes are arranged in a spiral.

[0013] Furthermore, in the above-mentioned device, the condensate return pipe includes a horizontal section and a vertical section, the upper end of the vertical section is connected to the heat release section, the lower end of the vertical section is connected to one end of the horizontal section, and the other end of the horizontal section is connected to the heat absorption section.

[0014] Furthermore, in the above-mentioned device, the device also includes a medium inlet pipe, the medium inlet pipe is connected to the condensate return pipe, a water injection meter is arranged on the medium inlet pipe, and a second gate valve is respectively arranged on both sides of the water injection meter.

[0015] Furthermore, in the above-mentioned device, the vertical section includes two branch pipes and a main pipe, the upper ends of the two branch pipes are connected to the heat release section, the lower ends of the two branch pipes are combined and connected to the upper end of the main pipe, the lower end of the main pipe is connected to one end of the horizontal section, and the other end of the horizontal section is connected to the heat absorption section, each of the branch pipes is provided with a third gate valve, and the two third gate valves constitute a valve group; the valve group is used to adjust the flow rate of the condensed water from the medium in the reflux pipe into the heat absorption section, so as to control the wall temperature of the heating surface of the heat absorption section to be above the acid dew point temperature of the boiler fuel.

[0016] Furthermore, in the above-mentioned device, the device also includes a flue inlet diffusion section and a flue outlet contraction section, the flue inlet diffusion section is arranged on the flue gas inlet side of the heat absorption section, and the flue outlet contraction section is arranged on the flue gas discharge side of the heat absorption section; the device also includes an air duct inlet diffusion section and an air duct outlet contraction section, the air duct inlet diffusion section is arranged on the air inlet side of the heat release section, and the air duct outlet contraction section is arranged on the air discharge side of the heat release section.

[0017] Furthermore, in the above-mentioned device, the heat absorption section includes a high-temperature heat absorption section and a low-temperature heat absorption section, and the flue gas passes through the high-temperature heat absorption section and the low-temperature heat absorption section in sequence; the heat release section includes a high-temperature heat release section and a low-temperature heat release section, and the air passes through the low-temperature heat release section and the high-temperature heat release section in sequence; two saturated steam connecting pipes are provided, and two condensate self-return pipes are provided; the medium in the high-temperature heat absorption section after the flue gas is heated enters the high-temperature heat release section through one of the saturated steam connecting pipes, and the medium that has completed heat release in the high-temperature heat release section flows back to the high-temperature heat absorption section through one of the condensate self-return pipes; the medium in the low-temperature heat absorption section after the flue gas is heated enters the low-temperature heat release section through another of the saturated steam connecting pipes, and the medium that has completed heat release in the low-temperature heat release section flows back to the low-temperature heat absorption section through another of the condensate self-return pipes.

[0018] Analysis shows that the present invention discloses a micro-cyclone flue gas waste heat utilization device, which adopts micro-cyclone flue gas waste heat utilization technology to recover the waste heat of the flue gas, reduces the outlet flue gas temperature of the boiler flue, and uses the recovered waste heat to heat the air, thereby reducing the fuel consumption per unit output and further improving the safe and economical operation of the boiler rear heating surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0020] Figure 1 It is a structural schematic diagram of an embodiment of the present invention.

[0021] Figure 2 It is a schematic structural diagram of a heat exchange unit according to an embodiment of the present invention.

[0022] Figure 3 It is a three-dimensional schematic diagram of a lined perforated pipe according to an embodiment of the present invention.

[0023] Explanation of reference numerals: 1 flue; 2 heat absorption section; 3 air duct; 4 heat release section; 5 saturated steam connecting pipe; 6 condensate self-return pipe; 7 first gate valve; 8 second gate valve; 9 liner perforated pipe; 10 through hole; 11 safety valve; 12 medium inlet pipe; 13 water injection water meter; 14 third gate valve; 15 flue inlet diffusion section; 16 flue outlet contraction section; 17 heat absorption high temperature section; 18 heat absorption low temperature section; 19 heat release high temperature section; 20 heat release low temperature section; 21 air duct inlet diffusion section; 22 air duct outlet contraction section; 23 upper main pipe bundle; 24 lower main pipe bundle; 25 branch pipe bundle; 26 first header pipe; 27 second header pipe; 28 third header pipe; 29 fourth header pipe. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present invention and does not limit the present invention. In fact, it will be clear to those skilled in the art that modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as a part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desired that the present invention encompasses such modifications and variations within the scope of the appended claims and their equivalents.

[0025] In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. The terms "connected", "connected" and "set" used in the present invention should be understood in a broad sense. For example, they can be fixedly connected or detachably connected; they can be directly connected or indirectly connected through intermediate components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0026] like Figures 1 to 3 As shown, according to an embodiment of the present invention, a micro-vortex flue gas waste heat utilization device is provided, which can utilize the waste heat of the flue gas in the boiler flue 1 to heat the air. The device includes a heat exchanger, which includes a heat absorption section 2 and a heat release section 4. The height of the heat release section 4 is higher than the height of the heat absorption section 2. Preferably, the distance between the heat release section 4 and the heat absorption section 2 is greater than or equal to 1 meter. The outer periphery of the tube cavity of the heat absorption section 2 and the heat release section 4 are both provided with annular fins. The heat absorption section 2 is installed at the tail of the flue 1. The flue gas passes through the heat absorption section 2 and heats the medium in the heat absorption section 2 before being discharged. The heat release section 4 is installed in the air duct 3. The air entering the boiler through the air duct 3 passes through the heat release section 4. The medium enters the heat release section 4 after being heated by the flue gas and heats the air. The medium that has completed heat release in the heat release section 4 flows back to the heat absorption section 2. The medium can form a micro-vortex when flowing in the heat absorption section 2 and the heat release section 4.

[0027] Furthermore, the device also includes a saturated steam connecting pipe 5 and a condensed water self-return pipe 6. The medium heated by flue gas enters the heat release section 4 through the saturated steam connecting pipe 5, and the medium that has completed heat release in the heat release section 4 returns to the heat absorption section 2 through the condensed water self-return pipe 6; a first gate valve 7 is provided on the saturated steam connecting pipe 5, and a safety valve 11 is connected to the first gate valve 7. The first gate valve 7 is in a normally open state, and closing the first gate valve 7 can conveniently repair or replace the safety valve 11. When the pressure of the saturated steam connecting pipe 5 increases to a predetermined value, the safety valve 11 automatically opens to release the pressure, and the saturated steam in the saturated steam connecting pipe 5 is exhausted, thereby preventing the pressure of the saturated steam connecting pipe 5 from continuing to increase. When the pressure in the saturated steam connecting pipe 5 drops to a specified value, the safety valve 11 is automatically closed in time, thereby preventing a large amount of medium in the saturated steam connecting pipe 5 from being lost. Preferably, the medium circulating in the closed loop formed by the heat absorption section 2, the saturated steam connecting pipe 5, the heat release section 4 and the condensed water self-return pipe 6 is desalted water.

[0028] Specifically, when the flue gas in the flue 1 passes through the heat absorbing section 2, the water in the heat absorbing section 2 is heated and converted into saturated steam. The saturated steam enters the heat releasing section 4 through the saturated steam connecting pipe 5. In the heat releasing section 4, the saturated steam exchanges heat with the air passing through the heat releasing section 4 to heat the air. After releasing heat, the saturated steam is converted into saturated water. Under the action of gravity, the saturated water flows back to the heat absorbing section 2 through the condensed water self-reflux pipe 6, completing the superconducting heat absorption and heat release process.

[0029] Furthermore, the heat absorbing section 2 and the heat releasing section 4 are both composed of a plurality of heat exchanging units arranged in sequence and overlapped with each other. The heat exchanging units in the heat absorbing section 2 are arranged perpendicularly to the direction of flue gas flow, and the heat exchanging units in the heat releasing section 4 are arranged perpendicularly to the direction of air flow. Figure 2As shown, the heat exchange unit includes an upper main pipe bundle 23, a lower main pipe bundle 24 and a plurality of branch pipe bundles 25 connecting the upper main pipe bundle 23 and the lower main pipe bundle 24, the branch pipe bundle 25 is perpendicular to the upper main pipe bundle 23 and the lower main pipe bundle 24, the upper main pipe bundles 23 of the several heat exchange units of the heat absorption section 2 are connected to one end of the saturated steam connecting pipe 5 through the first header pipe 26, the upper main pipe bundles 23 of the several heat exchange units of the heat release section 4 are connected to the other end of the saturated steam connecting pipe 5 through the second header pipe 27, the lower main pipe bundles 24 of the several heat exchange units of the heat absorption section 2 are connected to one end of the condensate self-return pipe 6 through the third header pipe 28, and the lower main pipe bundles 24 of the several heat exchange units of the heat release section 4 are connected to the other end of the condensate self-return pipe 6 through the fourth header pipe 29. In the tube cavity of the heat absorption section 2 and the heat release section 4, the branch tube bundle 25 is sleeved with a liner perforated tube 9, the outer wall of the liner perforated tube 9 is attached to the inner wall of the branch tube bundle 25, and the two ends of the liner perforated tube 9 are fixed to the two ends of the branch tube bundle 25 by welding. Figure 3 As shown, the tube wall of the liner perforated tube 9 is covered with through holes 10, and the through holes 10 are arranged in a spiral. The spiral arrangement means that the through holes 10 in the adjacent left and right columns are staggered up and down. Specifically, a plurality of parallel and spaced through hole groups are arranged on the liner perforated tube 9 along the axial direction of the liner perforated tube 9, and each through hole group includes a plurality of through holes 10 uniformly distributed on the liner perforated tube 9 along the circumference of the liner perforated tube 9, that is, in the side wall expansion diagram of the liner perforated tube 9, a plurality of through holes 10 are arranged in an array. The centers of all through holes 10 are located on the spiral line, so that the medium can form a micro-vortex when flowing in the branch tube bundle 25. Such a setting can increase the heat exchange area between the medium and the inner tube wall, effectively increase the heat exchange efficiency, and greatly increase the heat transfer effect. Preferably, the condensate self-return pipe 6 passes through the first collecting tube 26. At the position where the condensate self-return pipe 6 passes through the first collecting tube 26, the diameter of the condensate self-return pipe 6 is smaller than the diameter of the first collecting tube 26. The first collecting tube 26 can preheat the medium in the condensate self-return pipe 6.

[0030] Furthermore, the outer diameter of the branch tube bundle 25 is 38 mm, and the wall thickness is generally 3.5 mm, the outer diameter of the inner lining perforated tube 9 is 32 mm, and the wall thickness is about 3 mm, the diameter of the through hole 10 is 14 mm, 15 mm or 16 mm, and the arrangement of the plurality of through holes 10 is staggered, for example, the plurality of through holes are divided into a plurality of rows along the circumference of the inner lining perforated tube 9, and the through holes 10 of two adjacent rows are not on the cross section of the same inner lining perforated tube 9. Such an arrangement can generate micro-swirl when the medium flows in the branch tube bundle 25, thereby making the branch tube bundle 25 have a better enhanced heat transfer effect.

[0031] During the flow of the medium in the branch tube bundle 25, under the action of the inner lining perforated tube 9, the medium forms a number of vortices of different sizes in the inner lining perforated tube 9, thereby forming a micro-vortex, which is more turbulent and can effectively increase the heat exchange efficiency and greatly increase the heat transfer effect.

[0032] In order to increase the heat transfer effect, a plurality of convex teeth are arranged on the inner tube wall of the lining perforated tube 9, each convex tooth includes a plurality of convex parts, and a through hole 10 is formed between two adjacent convex parts. The convex teeth are spirally distributed along the tube wall, and a groove is formed between two adjacent convex teeth. The convex teeth and the groove together form a thread on the inner tube wall of the lining perforated tube 9, so that the medium can also form a micro-vortex when flowing in the lining perforated tube 9. Such a setting can increase the heat exchange area between the medium and the inner tube wall, effectively increase the heat exchange efficiency, and greatly increase the heat transfer effect.

[0033] The outer circumference of each branch tube bundle 25 is sleeved with a plurality of annular fins in sequence along the length direction of the branch tube bundle 25. The annular fins are provided with a plurality of grooves extending from the top of the annular fins to the outer surface of the branch tube bundle 25. The grooves promote the flow of flue gas between the annular fins and enable the flue gas to form micro-vortices, thereby improving the heat exchange effect. Therefore, under the condition of transferring the same amount of heat, the heat transfer area can be saved and the metal consumption can be reduced. Since the grooves promote the flow of flue gas between the annular fins, dust and scaling are not easily accumulated between the annular fins.

[0034] Furthermore, two saturated steam connecting pipes 5 are provided, two condensed water self-return pipes 6 are provided, the heat absorption section 2 includes a heat absorption high temperature section 17 and a heat absorption low temperature section 18, and the flue gas sequentially passes through the heat absorption high temperature section 17 and the heat absorption low temperature section 18. The heat release section 4 includes a heat release high temperature section 19 and a heat release low temperature section 20, and the air sequentially passes through the heat release low temperature section 20 and the heat release high temperature section 19, that is, the heat absorption high temperature section 17, a saturated steam connecting pipe 5, a heat release high temperature section 19, a condensed water self-return pipe 6 and the heat absorption high temperature section 17 are sequentially connected to form a closed loop for medium circulation, and the heat absorption low temperature section 18, another saturated steam connecting pipe 5, a heat release low temperature section 20, another condensed water self-return pipe 6 and the heat absorption low temperature section 18 are sequentially connected to form another closed loop for medium circulation. After being heated by the flue gas, the medium in the heat absorbing high temperature section 17 enters the heat releasing high temperature section 19 through a saturated steam connecting pipe 5, and the medium that has completed heat release in the heat releasing high temperature section 19 flows back to the heat absorbing high temperature section 17 through a condensed water self-return pipe 6; the medium in the heat absorbing low temperature section 18 after being heated by the flue gas enters the heat releasing low temperature section 20 through another saturated steam connecting pipe 5, and the medium that has completed heat release in the heat releasing low temperature section 20 flows back to the heat absorbing low temperature section 18 through another condensed water self-return pipe 6.

[0035] Furthermore, the condensed water self-return pipe 6 includes a horizontal section and a vertical section, the upper end of the vertical section is connected to the heat release section 4, the lower end of the vertical section is connected to one end of the horizontal section, and the other end of the horizontal section is connected to the heat absorption section 2.

[0036] Furthermore, the device also includes a medium inlet pipe 12, which is connected to the condensed water self-return pipe 6, and a water injection meter 13 is arranged on the medium inlet pipe 12, and a second gate valve 8 is arranged on both sides of the water injection meter 13. When it is necessary to add medium to the heat exchanger, the two second gate valves 8 are opened, and the medium can be added to the heat exchanger through the medium inlet pipe 12, and the water injection meter 13 can measure the amount of the added medium. After closing the two second gate valves 8, the water injection meter 13 can be easily repaired or replaced.

[0037] Furthermore, the vertical section includes two branch pipes and one main pipe, the upper ends of the two branch pipes are connected to the heat release section 4, the lower ends of the two branch pipes are connected to the upper end of the main pipe after being collected, and the lower end of the main pipe is connected to one end of the horizontal section, and each branch pipe is provided with a third gate valve 14. The two branch pipes, one main pipe and two third gate valves 14 form a valve group for controlling the flow of the medium in the condensed water self-return pipe 6. The device also includes a wall temperature tester, and the wall temperature monitoring points are provided on the heated surface walls of the heat absorbing high temperature section 17 and the heat absorbing low temperature section 18. The wall temperature tester is arranged on the wall temperature monitoring point, and the two wall temperature testers are used to measure the temperature of the pipe wall of the heat absorbing high temperature section 17 and the heat absorbing low temperature section 18 respectively. The valve group is used to adjust the flow of condensed water from the medium in the return pipe 6 into the heat absorption section 2, and then adjust the pressure in the heat exchanger to adjust the temperature of the tube wall of the heat absorption high temperature section 17 and the heat absorption low temperature section 18, so as to control the wall temperature of the heating surface of the heat absorption high temperature section 17 and the heat absorption low temperature section 18 above the acid dew point temperature of the boiler fuel, ensuring that the heat exchanger does not condense and corrode. While making full use of the waste heat of the flue gas, it also ensures the long-term safe operation of the device.

[0038] Furthermore, the device also includes a flue inlet diffusion section 15 and a flue outlet contraction section 16, the flue inlet diffusion section 15 is arranged on the flue gas inlet side of the heat absorption section 2, and the flue outlet contraction section 16 is arranged on the flue gas discharge side of the heat absorption section 2; the device also includes an air duct inlet diffusion section 21 and an air duct outlet contraction section 22, the air duct inlet diffusion section 21 is arranged on the air inlet side of the heat release section 4, and the air duct outlet contraction section 22 is arranged on the air discharge side of the heat release section 4.

[0039] In one embodiment, the high-temperature flue gas heats the water in the heat absorbing high-temperature section 17 and the heat absorbing low-temperature section 18 respectively, and the water in the heat absorbing high-temperature section 17 is heated to 150°C, and the water in the heat absorbing low-temperature section 18 is heated to 110°C, thereby greatly reducing the exhaust temperature, allowing the heating surface to operate at a safe temperature, and improving the thermal efficiency. The pressure in the closed loop formed by the heat absorbing high-temperature section 17 and the heat releasing high-temperature section 19 is 0.476MPa, and the pressure in another closed loop formed by the heat absorbing low-temperature section 18 and the heat releasing low-temperature section 20 is 0.143MPa.

[0040] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0041] 1. The micro-cyclonic flue gas waste heat utilization device is a static device that does not require external power and circulates naturally with the help of gravity;

[0042] 2. The valve group is used to control the reflux rate of saturated water to increase or decrease the internal pressure of the heat absorption section 2 (increase or decrease the temperature), so as to control the wall temperature of the heat absorption high temperature section 17 and the heat absorption low temperature section 18 to be higher than the fuel acid dew point; while the device can reduce the exhaust gas temperature to the greatest extent, it can also make the device operate safely for a long period of time;

[0043] 3. The heat absorption section 2 and the heat release section 4 are designed separately and arranged in a zero-activity manner;

[0044] 4. The heat absorption section 2 and the heat release section 4 are matched in high and low positions, which is convenient for inspection and maintenance.

[0045] The present invention discloses a micro-cyclone flue gas waste heat utilization device, which adopts micro-cyclone flue gas waste heat utilization technology to recover the waste heat of the flue gas, thereby reducing the outlet exhaust temperature of the boiler flue 1, and utilizing the recovered waste heat to heat the air in the air duct 4, thereby reducing the fuel consumption per unit output and further improving the safe and economical operation of the heating surface at the rear of the boiler.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A micro-cyclonic flue gas waste heat utilization device, which can utilize the waste heat of flue gas in the boiler flue to heat the air entering the boiler, characterized in that: The device comprises a heat exchanger, the heat exchanger comprises a heat absorbing section and a heat releasing section, the height of the heat releasing section is higher than the height of the heat absorbing section, and the outer peripheries of the tube cavities of the heat absorbing section and the heat releasing section are both provided with annular fins; The heat absorbing section is installed at the tail end of the flue, and the flue gas passes through the heat absorbing section and heats the medium in the heat absorbing section before being discharged; The heat release section is installed in the air duct, and the air entering the boiler through the air duct passes through the heat release section; The medium is heated by the flue gas and enters the heat release section to heat the air. The medium that has released heat in the heat release section flows back to the heat absorption section. The medium can form micro-swirls when flowing in the tube cavities of the heat absorbing section and the heat releasing section. The heat absorption section and the heat release section are both composed of a plurality of vertically parallel and spaced heat exchange units. The heat exchange units in the heat absorption section are arranged perpendicularly to the direction of flue gas flow, and the heat exchange units in the heat release section are arranged perpendicularly to the direction of air flow. The heat exchange unit includes an upper main pipe bundle, a lower main pipe bundle, and a plurality of branch pipe bundles connecting the upper main pipe bundle and the lower main pipe bundle. In the tube cavities of the heat absorption section and the heat release section, the branch tube bundle is sleeved with a liner perforated tube, the two ends of the liner perforated tube are welded to the two ends of the branch tube bundle, and the tube wall of the liner perforated tube is covered with through holes, which are arranged in a rotational manner; The centers of all through holes are located on the spiral line, so that the medium can form a micro-vortex when flowing in the branch pipe bundle.

2. The device according to claim 1, characterized in that The device also includes a saturated steam connecting pipe and a condensed water self-return pipe, the medium heated by flue gas enters the heat release section through the saturated steam connecting pipe, and the medium that has released heat in the heat release section flows back to the heat absorption section through the condensed water self-return pipe; The saturated steam connecting pipe is provided with a first gate valve, and a safety valve is connected to the first gate valve; The medium is water.

3. The device according to claim 2, characterized in that The upper main pipe bundles of the plurality of heat exchange units in the heat absorption section are all connected to one end of the saturated steam connecting pipe through a first header pipe, and the upper main pipe bundles of the plurality of heat exchange units in the heat release section are all connected to the other end of the saturated steam connecting pipe through a second header pipe; The lower main pipe bundles of the plurality of heat exchange units in the heat absorption section are all connected to one end of the condensed water self-return pipe through the third header pipe, and the lower main pipe bundles of the plurality of heat exchange units in the heat release section are all connected to the other end of the condensed water self-return pipe through the fourth header pipe; A plurality of annular fins are sleeved in sequence on the outer periphery of each branch tube bundle along the length direction of the branch tube bundle, and a plurality of grooves extending from the outer surface are arranged on the annular fin.

4. The device according to claim 1, characterized in that The outer diameter of the branch pipe bundle is 38 mm; The outer diameter of the lining perforated tube is 32 mm, the diameter of the through holes is 14 mm or 16 mm, and the through holes are arranged in a spiral.

5. The device according to claim 2, characterized in that The condensed water self-return pipe includes a horizontal section and a vertical section, the upper end of the vertical section is connected to the heat release section, the lower end of the vertical section is connected to one end of the horizontal section, and the other end of the horizontal section is connected to the heat absorption section.

6. The device according to claim 2, characterized in that The device also includes a medium inlet pipe, which is connected to the condensed water self-return pipe. A water injection meter is arranged on the medium inlet pipe, and a second gate valve is respectively arranged on both sides of the water injection meter.

7. The device according to claim 5, characterized in that The vertical section includes two branch pipes and a main pipe, the upper ends of the two branch pipes are connected to the heat release section, the lower ends of the two branch pipes are connected to the upper end of the main pipe after being collected, the lower end of the main pipe is connected to one end of the horizontal section, and the other end of the horizontal section is connected to the heat absorption section, each branch pipe is provided with a third gate valve, and the two third gate valves constitute a valve group; The valve group is used to adjust the flow rate of the condensed water from the medium in the reflux pipe into the heat absorption section, so as to control the wall temperature of the heating surface of the heat absorption section to be above the acid dew point temperature of the boiler fuel.

8. The device according to claim 1, characterized in that The device also includes a flue inlet diffusion section and a flue outlet contraction section, wherein the flue inlet diffusion section is arranged at the flue gas inlet side of the heat absorption section, and the flue outlet contraction section is arranged at the flue gas discharge side of the heat absorption section; The device also includes an air duct inlet diffusion section and an air duct outlet contraction section. The air duct inlet diffusion section is arranged on the air inlet side of the heat release section, and the air duct outlet contraction section is arranged on the air discharge side of the heat release section.

9. The device according to claim 2, characterized in that The heat absorption section includes a heat absorption high temperature section and a heat absorption low temperature section, and the flue gas passes through the heat absorption high temperature section and the heat absorption low temperature section in sequence; The heat release section includes a heat release high temperature section and a heat release low temperature section, and air passes through the heat release low temperature section and the heat release high temperature section in sequence; The saturated steam connecting pipes are provided with two, and the condensed water self-return pipes are provided with two; The medium in the heat absorbing high temperature section after being heated by flue gas enters the heat releasing high temperature section through the saturated steam connecting pipe, and the medium that has released heat in the heat releasing high temperature section flows back to the heat absorbing high temperature section through the condensed water reflux pipe; After the flue gas is heated, the medium in the heat absorbing low temperature section enters the heat releasing low temperature section through another saturated steam connecting pipe, and the medium that has released heat in the heat releasing low temperature section flows back to the heat absorbing low temperature section through another condensed water reflux pipe.

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