A boiler flue direct-connected flue gas waste heat recovery heat exchanger

Abstract

The present invention relates to the technical field of heat exchangers, and particularly relates to a boiler flue directly-connected flue gas waste heat recovery heat exchanger, which includes a box body and a heat exchange device. The heat exchange device includes a frame body and a plurality of heat exchange plates. The plurality of heat exchange plates define a plurality of hot air cavities and a plurality of cold air cavities on the frame body. A plurality of heat exchange tubes are arranged on each heat exchange plate. The heat exchange tubes include tube bodies and sponge layers, and the sponge layers are wound around the tube bodies. The boiler flue directly-connected flue gas waste heat recovery heat exchanger of the present invention recovers the waste heat of the flue gas by arranging a heat exchange device and heat exchange tubes on the heat exchange plates. After the flue gas enters the hot air cavity, it will flow in the hot air cavity and pass through the sponge layers on the heat exchange tubes. At this time, the water vapor in the flue gas will come to the cold air cavity along the sponge layers and liquefy into condensed water in the cold air cavity, thereby recovering the waste heat of the flue gas. On the basis of heat exchange on the heat exchange plates, auxiliary heat exchange is carried out in combination with the heat exchange tubes.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and particularly relates to a boiler flue direct-connected flue gas waste heat recovery heat exchanger. Background Art

[0002] A plate heat exchanger is a commonly used waste heat recovery device. It forms numerous microchannels by stacking multiple thin stainless steel plates, thereby achieving heat exchange. This heat exchanger has the advantages of compact structure, high temperature resistance, corrosion resistance, etc., and is widely used in various industries. When recovering the waste heat of boiler flue gas, the waste heat recovery device is installed at the outlet of the boiler flue. The flue gas waste heat enters one side of the waste heat recovery device from the flue gas inlet, and is sent out from the flue gas outlet after absorbing heat and cooling down through the waste heat recovery device. Normal temperature air is blown into the air inlet of the recovery device by a blower, enters the heating surface of the waste heat recovery device, and is sent out from the air outlet after being heated up by the waste heat recovery device. The hot air sent out can be used to flame retard or dry materials, etc. However, in actual use, although the heat exchange amount of this heat exchanger is relatively large, its heat exchange efficiency needs to be improved. Summary of the Invention

[0003] The present invention provides a boiler flue direct-connected flue gas waste heat recovery heat exchanger to solve the problem that although the existing heat exchanger has a relatively large heat exchange amount, its heat exchange efficiency needs to be improved during use.

[0004] The boiler flue direct-connected flue gas waste heat recovery heat exchanger of the present invention adopts the following technical solution: A boiler flue direct-connected flue gas waste heat recovery heat exchanger includes a box body and a heat exchange device, and the heat exchange device is installed inside the box body; the heat exchange device includes a frame body and a plurality of heat exchange plates. The plurality of heat exchange plates are sequentially arranged on the frame body along a first direction, and the first direction is the horizontal direction. The plurality of heat exchange plates define a plurality of hot air cavities and a plurality of cold air cavities that are sequentially arranged along the first direction on the frame body, and the hot air cavities and the cold air cavities are alternately distributed in sequence along the first direction; the hot air cavities are communicated in a second direction, and the second direction is the vertical direction. Flue gas passes through the hot air cavities. The cold air cavities are communicated in a third direction, and the third direction is horizontal and perpendicular to the first direction. Normal temperature gas passes through the cold air cavities; a plurality of heat exchange tubes are arranged on each heat exchange plate, and the plurality of heat exchange tubes are sequentially arranged on the corresponding heat exchange plate along the second direction. The heat exchange tubes pass through the hot air cavities along the first direction and extend into the cold air cavities adjacent to the hot air cavities; each heat exchange tube includes a tube body and a sponge layer; the tube body is columnar, and a through hole is coaxially opened on the tube body. The two ends along the axial direction of the tube body are respectively called the head end and the tail end. One end of the sponge layer is installed at the head end of the tube body, and the other end passes through the through hole and is wound around the tail end of the tube body.

[0005] Further, the box body is provided with a cold end inlet, a cold end outlet, a hot end inlet, and a flue connection port; the hot end inlet and the flue connection port are arranged face to face on the box body along the second direction, the hot end inlet is communicated with the flue connection port through a hot air cavity, the cold end inlet and the cold end outlet are arranged face to face on the box body along the third direction, and the cold end inlet is communicated with the cold end outlet through a cold air cavity.

[0006] Further, the pipe body is inclined. The part of the pipe body located in the hot air cavity is called the first pipe section, and the part of the pipe body located in the cold air cavity is called the second pipe section; the two ends of the first pipe section along the axis direction of the pipe body are respectively called the first end and the second end. The first end is located on the side of the second end far from the second pipe section in the axis direction of the pipe body, the first end is located on the side of the second end close to the hot end inlet in the second direction, and the sponge layer on one side of the first pipe section abuts against the heat exchange plate. Two water collecting plates are arranged on the side of the hot end inlet. Both of the two water collecting plates are located in the hot air cavity, and the two water collecting plates are respectively arranged on the heat exchange plate where the pipe body is located and another heat exchange plate adjacent to the heat exchange plate in the first direction.

[0007] Further, a water collecting groove is formed in the water collecting plate, and a water pipe is connected to the lower end of the water collecting plate.

[0008] Further, the inside of the pipe body is hollow. The pipe body has a corrugated section, which is located on one side of the second pipe section and is in the cold air cavity. The inside of the pipe body is filled with an expansion liquid, and the expansion liquid can expand when heated.

[0009] Further, the inclination directions of the pipe bodies on every two adjacent heat exchange plates in the first direction are opposite.

[0010] Further, a sleeve is arranged inside the pipe body. The sleeve is located in the through hole and is coaxial with the through hole.

[0011] Further, protective films are arranged at both ends of the through hole.

[0012] Further, a heat insulation layer is arranged between the heat exchange device and the box body, and heat insulating cotton is arranged on the heat insulation layer.

[0013] Further, the heat exchange pipe is installed on the heat exchange plate through a mounting plate.

[0014] The beneficial effects of the present invention are as follows: A direct-connected flue gas waste heat recovery heat exchanger for a boiler of the present invention is provided with a heat exchange device, and heat exchange tubes are arranged on the heat exchange plates. When in use, flue gas is introduced into the hot air cavity. After entering the hot air cavity, the flue gas will flow in the hot air cavity and pass through the sponge layer on the heat exchange tubes. At this time, the water vapor in the flue gas will come along the sponge layer to the cold air cavity and liquefy into condensed water in the cold air cavity. Latent heat is released in this process, and part of the liquefied condensed water will be carried away by the air in the cold air cavity. In this process, the condensed water evaporates, taking away more heat, and recovering the waste heat of the flue gas. On the basis of heat exchange on the heat exchange plates, auxiliary heat exchange is carried out in combination with the heat exchange tubes, improving the heat exchange efficiency of the heat exchange device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 Schematic diagram of the overall structure of an embodiment of a direct-connected flue gas waste heat recovery heat exchanger for a boiler of the present invention;

[0017] Figure 2 Top view of the overall structure of an embodiment of a direct-connected flue gas waste heat recovery heat exchanger for a boiler of the present invention;

[0018] Figure 3 For Figure 2 Cross-sectional view along A-A in

[0019] Figure 4 Schematic diagram of the heat exchange device of an embodiment of a direct-connected flue gas waste heat recovery heat exchanger for a boiler of the present invention;

[0020] Figure 5 Front view of the heat exchange device of an embodiment of a direct-connected flue gas waste heat recovery heat exchanger for a boiler of the present invention;

[0021] Figure 6 For Figure 5 Cross-sectional view along B-B in

[0022] Figure 7 Schematic diagram of a partial structure of the heat exchange device of an embodiment of a direct-connected flue gas waste heat recovery heat exchanger for a boiler of the present invention;

[0023] Figure 8 For Figure 7 Enlarged view at C in

[0024] Figure 9 Distribution diagram of multiple heat exchange tubes on the heat exchange plate of an embodiment of a boiler flue directly connected flue gas waste heat recovery heat exchanger of the present invention;

[0025] Figure 10 Schematic diagram of the heat exchange tube and the mounting plate of an embodiment of a boiler flue directly connected flue gas waste heat recovery heat exchanger of the present invention;

[0026] Figure 11 Schematic diagram of the heat exchange tube of an embodiment of a boiler flue directly connected flue gas waste heat recovery heat exchanger of the present invention;

[0027] Figure 12 is Figure 11 Cross-sectional view along D-D in;

[0028] Figure 13 Cross-sectional view of the tube body of an embodiment of a boiler flue directly connected flue gas waste heat recovery heat exchanger of the present invention.

[0029] In the figure: 100, box body; 110, cold end inlet; 120, cold end outlet; 130, hot end inlet; 140, flue connection port; 150, insulation layer; 160, water collecting plate; 170, water pipe; 200, heat exchange device; 210, frame body; 220, heat exchange plate; 230, hot air cavity; 240, cold air cavity; 250, heat exchange tube; 251, tube body; 252, sponge layer; 253, corrugated section; 254, sleeve; 255, protective film; 260, mounting plate. Specific embodiments

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] An embodiment of a boiler flue directly connected flue gas waste heat recovery heat exchanger of the present invention, as Figures 1 to 13 shown.

[0032] A boiler flue directly connected flue gas waste heat recovery heat exchanger includes a box body 100 and a heat exchange device 200, and the heat exchange device 200 is installed in the box body 100.

[0033] The heat exchange device 200 includes a frame body 210 and a plurality of heat exchange plates 220. The plurality of heat exchange plates 220 are sequentially arranged on the frame body 210 along a first direction, and the first direction is the horizontal direction. The plurality of heat exchange plates 220 define a plurality of hot air chambers 230 and a plurality of cold air chambers 240 that are sequentially arranged along the first direction on the frame body 210, and the hot air chambers 230 and the cold air chambers 240 are alternately distributed in sequence in the first direction. The hot air chambers 230 communicate with each other in a second direction, and the second direction is the vertical direction. Flue gas passes through the hot air chambers 230. The cold air chambers 240 communicate with each other in a third direction, and the third direction is the horizontal direction perpendicular to the first direction. Normal temperature gas passes through the cold air chambers 240. The cold air chambers 240 and the hot air chambers 230 are independent of each other.

[0034] See the appendix Figure 1 As shown, the first direction is the direction shown by the X-axis in the appendix Figure 1 The second direction is the direction shown by the Y-axis in the appendix Figure 1 The third direction is the direction shown by the Z-axis in the appendix Figure 1

[0035] A plurality of heat exchange tubes 250 are arranged on each heat exchange plate 220. The plurality of heat exchange tubes 250 are sequentially arranged on the corresponding heat exchange plate 220 along the second direction. The heat exchange tubes 250 pass through the hot air chambers 230 along the first direction and extend into the cold air chambers 240 adjacent to the hot air chambers 230. The heat exchange tubes 250 include a tube body 251 and a sponge layer 252. The tube body 251 is columnar, and a through hole is coaxially provided on the tube body 251. The two ends along the axial direction of the tube body 251 are respectively called the head end and the tail end. One end of the sponge layer 252 is installed at the head end of the tube body 251, and the other end passes through the through hole and is wound around the tail end of the tube body 251.

[0036] Specifically, the heat exchange tubes 250 are installed on the heat exchange plates 220 through mounting plates 260.

[0037] In this embodiment, by providing the heat exchange device 200 and arranging the heat exchange tubes 250 on the heat exchange plates 220, during use, flue gas is introduced into the hot air chambers 230. After entering the hot air chambers 230, the flue gas will flow in the hot air chambers 230 and pass through the sponge layer 252 on the heat exchange tubes 250. The water vapor in the flue gas will follow the sponge layer 252 to the cold air chambers 240 and liquefy into condensed water in the cold air chambers 240. Latent heat is released in this process, and part of the liquefied condensed water will be carried away by the air in the cold air chambers 240. In this process, the condensed water evaporates, taking away more heat, recovering the waste heat of the flue gas. On the basis of heat exchange of the heat exchange plates 220, auxiliary heat exchange is combined with the heat exchange tubes 250, improving the heat exchange efficiency of the heat exchange device 200.

[0038] In this embodiment, the box body 100 is provided with a cold end inlet 110, a cold end outlet 120, a hot end inlet 130, and a flue connection port 140. The hot end inlet 130 and the flue connection port 140 are arranged face to face on the box body 100 along the second direction. The hot end inlet 130 is communicated with the flue connection port 140 through a hot air cavity 230. The hot end inlet 130 is connected to a boiler flue, and the boiler flue is used to introduce flue gas into the hot air cavity 230. A chimney is arranged at the flue connection port 140 to facilitate the discharge of the flue gas after heat exchange. The cold end inlet 110 and the cold end outlet 120 are arranged face to face on the box body 100 along the third direction. The cold end inlet 110 is communicated with the cold end outlet 120 through a cold air cavity 240. The cold end inlet 110 is connected to an external fan, and the fan is used to convey normal temperature gas to the cold end inlet 110. The normal temperature gas can enter the cold air cavity 240 from the cold end inlet 110 and be discharged from the cold end outlet 120 after passing through the cold air cavity 240.

[0039] Further, a economizer is connected to the cold end outlet 120. By connecting an economizer to the cold end outlet 120, water can be heated. If only an economizer is connected, only water heating can be performed, and the effect is relatively single. Alternatively, a boiler can also be connected to the cold end outlet 120 for heating or drying materials.

[0040] In this embodiment, a heat insulation layer 150 is provided between the heat exchange device 200 and the box body 100, and heat insulation cotton is provided on the heat insulation layer 150. By providing the heat insulation layer 150 and the heat insulation cotton, heat loss is prevented.

[0041] In this embodiment, the pipe body 251 is inclined. The part of the pipe body 251 located in the hot air cavity 230 is called the first pipe section, and the part of the pipe body 251 located in the cold air cavity 240 is called the second pipe section. The two ends of the first pipe section along the axial direction of the pipe body 251 are respectively called the first end and the second end. The first end is located on the side of the second end away from the second pipe section in the axial direction of the pipe body 251. The first end is located on the side of the second end close to the hot end inlet 130 in the second direction. And the sponge layer 252 on one side of the first pipe section abuts against the heat exchange plate 220. Two water collecting plates 160 are arranged on one side of the hot end inlet 130. Both of the two water collecting plates 160 are located in the hot air cavity 230. The two water collecting plates 160 are respectively arranged on the heat exchange plate 220 where the pipe body 251 is located and another heat exchange plate 220 adjacent to the heat exchange plate 220 in the first direction. A space allowing flue gas to flow is left between the two water collecting plates 160.

[0042] Specifically, the water collecting plate 160 is provided with a water collecting groove, and the lower end of the water collecting plate 160 is connected to a water pipe 170, and the water pipe 170 is communicated with the water collecting groove.

[0043] The heat exchange tube 250 is tilted and the first end of the first tube section is located on the side of the second end thereof close to the hot end inlet 130 in the second direction, that is, the first end is located below the second end. When in use, the condensed water after liquefaction through the cold air chamber 240 can flow back to the hot air chamber 230 through the sponge layer 252, flow downward along the surface of the heat exchange plate 220 in the hot air chamber 230, and finally enter the water collecting tank and be led out from the water pipe 170, so as to prevent the condensed water from flowing back to the boiler flue and causing corrosion. The structure is simple, and the transition flue and other structures connecting the device and the boiler flue are omitted, so as to reduce the equipment installation investment cost. Moreover, part of the carbon dioxide and nitrogen oxides in the flue gas flow away with the condensed water to avoid entering the atmosphere, thereby reducing the emission of polluting gases.

[0044] In this embodiment, the tube body 251 is hollow inside and has a corrugated section 253 . The corrugated section 253 is located on one side of the second tube section and in the cold air cavity 240 . The tube body 251 is filled with expansion fluid that can expand when heated.

[0045] Furthermore, the inclination directions of the tubes 251 on every two heat exchange plates 220 adjacently arranged in the first direction are opposite.

[0046] In a further embodiment, the multiple heat exchange tubes 250 on the same heat exchange plate 220 are divided into two groups, the number of heat exchange tubes 250 in each group is the same, the two groups of heat exchange tubes 250 are symmetrically arranged about the central axis of the heat exchange plate 220 in the second direction, and the inclination degrees of the multiple heat exchange tubes 250 in the same group are different.

[0047] By arranging the corrugated section 253 on the tube body 251, when in use, the expansion fluid inside the tube body 251 expands after being heated, so that the volume inside the tube body 251 increases, and then the corrugated section 253 stretches and lengthens. The stretching and lengthening of the corrugated section 253 will cause one side of the second tube section to extend in the cold air chamber 240, press against the side wall of the heat exchange plate 220, and cause the heat exchange plate 220 itself to deform, increase the volume of the cold air chamber 240, and allow more room temperature gas to enter the cold air chamber 240. The increase in air flow will enhance the gas flow during the heat exchange process, help the gas exchange during the heat exchange process, enhance the conduction and exchange of heat, and further improve the heat exchange efficiency. In addition, arranging the heat exchange tube 250 with different inclinations can adjust the timing of the extension of the second tube section of the heat exchange tube 250, control the degree of increase in the volume of the cold air chamber 240, and avoid a sudden increase in the volume of the cold air chamber 240.

[0048] Specifically, a sleeve 254 is disposed inside the tube body 251 , and the sleeve 254 is located in the through hole and is coaxial with the through hole.

[0049] By providing the sleeve 254, the tube body 251 is limited so that the tube body 251 can maintain a coaxial state when it is extended and against the inner wall of the heat exchange plate 220.

[0050] In this embodiment, both ends of the through hole are provided with a protective film 255. The protective film 255 is provided to prevent the condensed water after liquefaction from flowing directly through the through hole.

[0051] In combination with the above embodiments, the specific working process is as follows:

[0052] During use, the flue gas is passed into the hot air chamber 230 from the hot end inlet 130 side, and the normal temperature gas is sent into the cold air chamber 240 from the cold end inlet 110 side. The flue gas entering the hot air chamber 230 will exchange heat with the normal temperature gas entering the cold air chamber 240 through the heat exchange plate 220, and after entering the hot air chamber 230, the flue gas will flow in the hot air chamber 230 and pass through the sponge layer 252 on the heat exchange tube 250. The water vapor in the flue gas will follow the sponge layer 252 to the cold air chamber 240, and liquefy into condensed water in the cold air chamber 240. In this process, latent heat is released, and part of the liquefied condensed water will be carried away by the air in the cold air chamber 240. In this process, the condensed water evaporates and takes away more heat, so that the waste heat of the flue gas is recovered. On the basis of heat exchange of the heat exchange plate 220, auxiliary heat exchange is carried out in combination with the heat exchange tube 250. The condensed water liquefied by the cold air chamber 240 can flow back to the hot air chamber 230 through the sponge layer 252, flow downward along the surface of the heat exchange plate 220 in the hot air chamber 230, and finally enter the water collecting tank and be led out from the water pipe 170 to prevent the condensed water from flowing back to the boiler flue and causing corrosion. The expansion liquid inside the tube body 251 will also expand after being heated, so that the volume inside the tube body 251 increases, and then the corrugated section 253 stretches and lengthens. The stretching and lengthening of the corrugated section 253 will cause one side of the second tube section to extend in the cold air chamber 240, supporting the side wall of the heat exchange plate 220, causing the heat exchange plate 220 itself to deform, increasing the volume of the cold air chamber 240, so that more normal temperature gas can be introduced into the cold air chamber 240. The increase in air flow will enhance the gas flow in the heat exchange process, help the gas exchange in the heat exchange process, enhance the conduction and exchange of heat, and further improve the heat exchange efficiency.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A direct-connected flue gas waste heat recovery heat exchanger for a boiler flue, characterized in that: It includes a box body and a heat exchange device, and the heat exchange device is installed inside the box body; the heat exchange device includes a frame body and a plurality of heat exchange plates. The plurality of heat exchange plates are arranged in sequence on the frame body along a first direction, and the first direction is the horizontal direction. The plurality of heat exchange plates define a plurality of hot air cavities and a plurality of cold air cavities arranged in sequence along the first direction on the frame body, and the hot air cavities and the cold air cavities are alternately distributed in sequence in the first direction; the hot air cavity is communicated with flue gas from bottom to top in a second direction, and the second direction is the vertical direction. The cold air cavity is communicated in a third direction, and the third direction is the horizontal direction perpendicular to the first direction. Normal temperature gas is passed through the cold air cavity; a plurality of heat exchange tubes are arranged on each heat exchange plate, and the plurality of heat exchange tubes are arranged in sequence on the corresponding heat exchange plate along the second direction. The heat exchange tubes pass through the hot air cavity along the first direction and extend into the cold air cavity adjacent to the hot air cavity; the heat exchange tube includes a tube body and a sponge layer; the tube body is columnar, and a through hole is coaxially opened on the tube body. Protective films are arranged at both ends of the through hole. The two ends along the axis direction of the tube body are respectively called the head end and the tail end. One end of the sponge layer is installed at the head end of the tube body, and the other end passes through the through hole and is wound around the tail end of the tube body; the tube body is inclined. The part of the tube body in the hot air cavity is called the first tube section, and the part of the tube body in the cold air cavity is called the second tube section; the two ends of the first tube section along the axis direction of the tube body are respectively called the first end and the second end. The first end is located on the side of the second end away from the second tube section in the axis direction of the tube body, and the first end is located on the side of the second end close to the hot end inlet in the second direction. And the sponge layer on one side of the first tube section abuts against the heat exchange plate. There is a corrugated section on the tube body, and the corrugated section is located on one side of the second tube section and in the cold air cavity. The inside of the tube body is hollow and filled with expansion liquid. The expansion liquid can expand when heated to stretch and lengthen the corrugated section, so that the side of the second tube section extends in the cold air cavity and abuts against the side wall of the heat exchange plate, deforming the heat exchange plate to increase the volume of the cold air cavity; there are two water collecting plates on the side of the hot end inlet, and both water collecting plates are located in the hot air cavity. The two water collecting plates are respectively arranged on the heat exchange plate where the tube body is located and another heat exchange plate adjacent to the heat exchange plate in the first direction.

2. The direct-connected flue gas waste heat recovery heat exchanger for boiler flue according to claim 1, wherein: The box body is provided with a cold end inlet, a cold end outlet, a hot end inlet and a flue connection port; the hot end inlet and the flue connection port are arranged face to face on the box body along the second direction. The hot end inlet is communicated with the flue connection port through the hot air cavity. The cold end inlet and the cold end outlet are arranged face to face on the box body along the third direction. The cold end inlet is communicated with the cold end outlet through the cold air cavity.

3. A direct-connected flue gas waste heat recovery heat exchanger for a boiler flue according to claim 2, characterized in that: The water collecting plate is provided with a water collecting groove, and a water pipe is connected to the lower end of the water collecting plate.

4. A direct-connected flue gas waste heat recovery heat exchanger for a boiler flue according to claim 2, characterized in that: The inclination directions of the tube bodies on every two adjacent heat exchange plates arranged in the first direction are opposite.

5. The direct-connected flue gas waste heat recovery heat exchanger for a boiler flue according to claim 2, characterized in that: A sleeve is arranged inside the tube body, and the sleeve is located inside the through hole and coaxial with the through hole.

6. A direct-connected flue gas waste heat recovery heat exchanger for a boiler flue according to claim 1, characterized in that: A heat insulation layer is arranged between the heat exchange device and the box body, and heat insulation cotton is arranged on the heat insulation layer.

7. A direct-connected flue gas waste heat recovery heat exchanger for a boiler flue according to claim 1, characterized in that: The heat exchange tubes are installed on the heat exchange plates through mounting plates.

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