Heat exchange unit, flue gas waste heat recovery exchanger and process

Abstract

The present invention discloses a heat exchange unit, a flue gas waste heat recovery exchanger and a process. The flue gas waste heat recovery heat exchanger has at least one heat exchange unit. The box of the heat exchange unit is provided with a smoke inlet, a smoke exhaust port, an air inlet, an air outlet and a liquid discharge port. A plurality of heat exchange tubes are arranged in parallel in the box and connect the air inlet and the air outlet. The cross section of the heat exchange tube is rectangular or long runway-shaped, and its long central axis is perpendicular to the bottom surface of the box. The ends of the heat exchange tube are fixed on the through holes of the end plate. A spray device is arranged on the top of the inner cavity of the box. The upper smoke exhaust port and the lower smoke inlet of two adjacent heat exchange units are connected by a connecting pipe. The flue gas waste heat recovery exchanger is fully automatically cleaned. The water or cleaning liquid is sprayed by the spray device to clean the dirt in the box and on the outer wall of the heat exchange tube. Since each heat exchange unit is independent, it can realize the simultaneous heat exchange, cleaning and liquid discharge functions, and perform full efficiency work.

Description

Technical Field

[0001] The invention relates to the field of energy recovery equipment in textile industry production, in particular to a heat exchange unit, a flue gas waste heat recovery exchanger and a process. Background Art

[0002] The textile printing and dyeing industry consumes a lot of energy in the production process. Enterprises spend a lot of money on energy consumption every year. They mainly use electricity, fuel oil, gas, steam and other energy sources for desizing, scouring, rinsing, pad dyeing, high temperature and high pressure overflow dyeing, drying and shaping and other processes. Especially during the drying and shaping process, the equipment will emit a large amount of high temperature and harmful flue gas, causing pollution to the environment. The exhaust temperature is as high as 190℃-300℃, and the heat energy is wasted. Therefore, the heat energy recovery equipment of waste flue gas is needed by the textile printing and dyeing industry for energy saving and consumption reduction.

[0003] Existing flue gas waste heat recovery exchangers mostly use finned heat exchangers or tube-sheet heat exchangers. Finned heat exchangers achieve the purpose of enhancing heat transfer by adding fins to the heat exchange tubes. Due to its densely arranged fin structure, it is easy to accumulate dust and is not easy to clean. Tube-sheet heat exchangers are multiple heat exchange tubes welded or expanded on the end plates welded on the shell, and baffles are arranged on the heat exchange tubes to achieve the purpose of enhancing heat transfer. Since the heat exchange tubes are usually arranged in a honeycomb shape and the flue gas flows up and down in the shell, there is also a problem of difficulty in cleaning. Therefore, the heat exchange effect will be affected after the heat exchanger runs for a long time, and the heat energy recovery efficiency will be reduced. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned existing flue gas heat recovery exchangers that are easy to accumulate dirt and difficult to clean, the present invention provides a flue gas waste heat recovery exchanger with a simple and reasonable structure, easy operation and installation, and capable of completing heat exchange and cleaning at the same time, thereby preventing blockage from affecting the heat exchange effect, and having both economic and social benefits.

[0005] In order to achieve the above technical objectives, the present invention provides the following technical solutions and produces the following beneficial effects:

[0006] A heat exchange unit, comprising:

[0007] --Box: The box is provided with a smoke inlet and a smoke exhaust port, an air inlet and an air outlet at both ends, and a liquid discharge port at the bottom;

[0008] --Heat exchange tubes: Several heat exchange tubes are arranged in parallel in the box and connected with the air inlet and the air outlet. The cross section of the heat exchange tubes is rectangular or long runway-shaped, and the long central axis is perpendicular to the bottom surface of the box;

[0009] --End plate: It is arranged at the air inlet and outlet. The end plate is provided with a number of through holes corresponding to the pipe openings of the heat exchange tubes. The pipe openings at both ends of the heat exchange tubes are fixed on the through holes of the end plate;

[0010] --Spraying device: The spraying device is arranged at the top of the inner cavity of the box;

[0011] --The cold medium flows in the heat exchange tube, and the hot medium flows in the space inside the box and outside the heat exchange tube. The two exchange heat through the wall of the heat exchange tube.

[0012] The present invention is a rectangular tube heat exchanger, and the heat exchange unit is an independent unit. The number of heat exchange units can be increased or decreased to flexibly adapt to the working conditions of different smoke exhaust volumes, and it is also easy to install and transport. In view of the problem that the flue gas usually contains harmful impurities, long-term use of the flue gas waste heat recovery exchanger will cause blockage between the heat exchange tubes. The present invention adds a spray device to the box body to perform online cleaning during production. The cross-section of the heat exchange tube is rectangular or long runway-shaped and is arranged vertically. Compared with the existing tube-sheet heat exchanger, the heat exchange tubes are arranged in a honeycomb pattern, and the distance between the heat pipes is larger, which is conducive to thorough flushing and cleaning.

[0013] As a further improvement of the above technical solution:

[0014] The outer side surface of the end plate is indented from the end surfaces on both sides of the box body.

[0015] The outer side surface of the end plate can prevent the protrusion of the end plate from affecting the installation connection of the heat exchange unit. During installation, there is no need to strictly connect the heat exchange tubes of the previous heat exchange unit with the heat exchange tubes of the next heat exchange unit. It is only necessary to seal the two boxes at both ends and perform a sealing test to avoid air leakage and water leakage affecting the heat exchange effect, making installation easier.

[0016] Flange plates are extended on the outer periphery of the end faces on both sides of the box body, and a liquid level meter is installed on the box body.

[0017] When installing and connecting multiple heat exchange units, you only need to connect the flange plates of adjacent heat exchange units, which is easy to operate. The liquid level meter can be used to monitor the liquid level in the box to prevent the water level from being too high and affecting the ventilation effect.

[0018] A flue gas waste heat recovery exchanger assembled with the heat exchange unit according to claim 1,

[0019] --It has at least one heat exchange unit, the upper air outlet of two adjacent heat exchange units is connected to the lower air inlet, the upper smoke exhaust port is connected to the lower smoke inlet through a connecting pipe, and the liquid discharge port of each heat exchange unit is connected to the water tank;

[0020] --The air inlet of the front heat exchange unit is connected to the fan through the air supply cover, and the air outlet of the rear heat exchange unit is connected to the air outlet cover;

[0021] --The heat medium enters the inner cavity of the box from the smoke inlet of the rear heat exchange unit, flows along the connecting pipe into the next heat exchange unit, and is discharged from the smoke exhaust port of the front heat exchange unit; the cool medium is sent into the air inlet of the front heat exchange unit by the fan, flows along the heat exchange pipe to the rear heat exchange unit, and is discharged from its air outlet.

[0022] As a further improvement of the above technical solution:

[0023] The connecting pipe is semicircular.

[0024] In order to achieve a good heat exchange effect, it is necessary to increase the length of the flue gas flow trajectory. The present invention increases the number of heat exchange units and sets a connecting pipe between the upper smoke exhaust port and the next smoke inlet, forcing the flue gas to flow in a certain direction, thereby making the heat exchange more sufficient and improving the heat exchange effect. At the same time, the flue gas flows up and down on the water surface in the box, which can stir the water surface to further rinse, soak and peel off the dirt on the box and the outer wall of the heat exchange tube.

[0025] A flue gas waste heat recovery process using the exchanger according to claim 4, comprising the following steps:

[0026] --Step I: The refrigerant flows in the heat exchange tube and exchanges heat with the heat medium outside the tube through the tube wall;

[0027] --Step II: After working for a period of time, spray and soak in one of the heat exchange units to clean the dirt outside the tube wall online; after cleaning, discharge the cleaning liquid through the drain port;

[0028] --Step III: Continue online cleaning in the next heat exchange unit as in step II.

[0029] As a further improvement of the above technical solution:

[0030] The liquid level of the cleaning liquid is 1 / 2 to 2 / 3 of the height of the box body.

[0031] The spraying takes water from the water tank to achieve water recycling.

[0032] High-temperature harmful flue gas is discharged from the upper-level equipment and enters the flue gas waste heat recovery exchanger. The flue gas flows in the box outside the heat exchange tube and transfers the heat energy to the heat exchange tube. The cold air is transported in the heat exchange tube, and the heat exchange tube transfers the heat energy to the cold air to realize heat exchange. Finally, the hot air is output from the air outlet hood to complete the heat exchange and is transported to the next-level equipment. The use of the flue gas waste heat recovery exchanger can effectively recycle and utilize the high-temperature harmful flue gas discharged by the drying and shaping equipment, which has both economic and social benefits.

[0033] The flue gas waste heat recovery exchanger is fully automatically cleaned. A small amount of water or cleaning liquid is filled in the box to soak and clean stubborn dirt. Since each heat exchange unit is independent, heat exchange, cleaning and drainage functions can be achieved simultaneously. After the flue gas enters the next unit from the previous heat exchange unit, the spray pipe of the previous heat exchange unit draws clean water or cleaning liquid from the water tank to spray and flush the heat exchange tube. After cleaning, the waste liquid is discharged into the water tank from the drain port. The remaining heat exchange units continue to exchange heat. After 15-20 minutes of cleaning, the previous heat exchange unit can be immediately put into heat exchange work and work at full efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the flue gas waste heat recovery exchanger of the present invention.

[0035] Figure 2 It is a schematic structural diagram of the heat exchange unit of the present invention.

[0036] Figure 3 for Figure 2 Enlarged view of part A in the middle.

[0037] Figure 4 A top view of the heat exchange unit.

[0038] Figure 5 for Figure 4 Cross-section of BB.

[0039] In the figure: 1. heat exchange unit; 11. box body; 111. smoke inlet; 112. smoke exhaust outlet; 113. liquid drain outlet; 114. air inlet; 115. air outlet; 12. support; 13. end plate; 14. heat exchange tube; 15. spray device; 16. liquid level gauge; 17. flange plate; 2. fan; 3. air supply hood; 4. air outlet hood; 5. connecting pipe; 6. water tank. DETAILED DESCRIPTION

[0040] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0041] like Figure 1 As shown, a support 12 is installed at the bottom of the heat exchange unit 1 of the flue gas waste heat recovery exchanger to support the heat exchange unit 1 and place it on the ground. The front and rear ends of the box body 11 of the heat exchange unit 1 are open to form an air inlet 114 and an air outlet 115 respectively. The fan 2 is connected to the air inlet 114 through the air supply hood 3, so that the fan 2 inputs fresh cold air into the heat exchange unit 1, and the rear end air outlet 115 is connected to the air outlet hood 4, so as to discharge the hot air in the heat exchange unit 1 after heat exchange.

[0042] like Figures 1 to 5As shown, the flue gas waste heat recovery exchanger of the present invention is formed by connecting at least one section of heat exchange unit 1. It can be flexibly adapted to equipment with different smoke exhaust volumes by increasing or reducing the number of heat exchange units 1, and it is also convenient for transportation. In this embodiment, three heat exchange units 1 are set, and flange plates 17 are extended on the outer periphery of the two sides of the box body 11. The two adjacent heat exchange units 1 are connected and fixed by welding between two adjacent flange plates 17, and the installation is very convenient. The air inlet 114 and the air outlet 115 of the box body 11 are welded and fixed with end plates 13. The outer side surface of the end plate 13 is indented by 3-5mm from the edge of the box body 11 to prevent the protrusion of the end plate 13 from affecting the installation and connection of the heat exchange unit 1. During installation, there is no need to dock the heat exchange tube 14 of the upper heat exchange unit 1 with the heat exchange tube 14 of the next heat exchange unit 1. It is only necessary to seal the two adjacent boxes 11. The installation is simpler and can avoid air leakage and water leakage.

[0043] like Figure 1 , Figure 4 , Figure 5 As shown, a plurality of heat exchange tubes 14 are arranged horizontally in the box 11. The cross section of the heat exchange tubes 14 is rectangular or long runway-shaped, and the long central axis thereof is perpendicular to the bottom surface of the box 11. Compared with the honeycomb arrangement of the heat exchange tubes of the existing tube-sheet heat exchanger, it is more convenient to spray cleaning liquid from the top for flushing. Through holes corresponding to the heat exchange tubes 14 are opened on the end plate 13. The pipe openings of the heat exchange tubes 14 are connected to the through holes of the end plate 13 so that the heat exchange tubes 14 are connected to the air inlet 114 and the air outlet 115. The cold air blown out by the fan 2 can be blown from the previous heat exchange unit 1 into the next heat exchange unit 1. A smoke inlet 111 and a smoke exhaust port 112 are provided on the top of the box body 11. The upper smoke exhaust port 112 of two adjacent heat exchange units 1 is connected to the lower smoke inlet 111 by an arc-shaped connecting pipe 5. The smoke enters the box body 11 of the upper heat exchange unit 1 from the upper smoke inlet 111, then rises and enters the connecting pipe 5 from the upper smoke exhaust port 112 and is input into the lower smoke inlet 111 along the pipe wall, so that the smoke enters the box body 11 of the lower heat exchange unit 1. The above-mentioned transport trajectory is circulated until the smoke is discharged from the smoke exhaust port 112 of the last heat exchange unit 1. Adding the connecting pipe 5 can direct the transmission direction of the smoke, so that the heat exchange is more sufficient and the heat exchange effect is improved.

[0044] In actual use, high-temperature harmful flue gas is discharged from the upper-level equipment into the flue gas waste heat recovery exchanger, the flue gas flows in the box 11 outside the heat exchange tube 14, and transfers the heat energy to the heat exchange tube 14, the cold air delivered by the fan 2 is transported in the heat exchange tube 14, the heat exchange tube 14 transfers the heat energy to the cold air to realize heat exchange, and finally the hot air is output from the air outlet hood 4 and transported to the next-level equipment.

[0045] like Figure 1 , Figure 2 , Figure 4 , Figure 5As shown, a spray device 15 is provided at the top of the inner cavity of the box 11 of the heat exchange unit 1, and a drain port 113 is provided at the bottom. The drain port 113 and the spray device 15 are externally connected to the water tank 6. Usually, a small amount of water or cleaning liquid can be filled in the box 11, which can be used to soak and clean the stubborn dirt in the box 11 and the outer wall of the heat exchange tube 12. The flue gas flowing above the liquid surface can stir the water or cleaning liquid to further peel off the dirt. The spray device 15 extracts clean water or cleaning liquid from the water tank 6 and sprays it out, which can wash away the dirt and impurities left on the surface by the flue gas. A liquid level meter 16 is provided in the box 11 for monitoring the liquid level. When the liquid level in the box 11 accumulates to 1 / 2~2 / 3 of the box height, the drain port 113 is opened to discharge the waste water into the water tank 6 to achieve waste water recycling.

[0046] In actual use, the flue gas waste heat recovery exchanger is fully automatically cleaned online without suspending the flue gas waste heat recovery work. Since each heat exchange unit 1 is independent, it can realize simultaneous heat exchange, cleaning and drainage functions. For example, after the flue gas enters the next one from the previous heat exchange unit 1, the previous heat exchange unit 1 can be sprayed, flushed and drained, and the remaining heat exchange units 1 continue to perform heat exchange. After 15-20 minutes of cleaning, the previous heat exchange unit 1 can be immediately put into heat exchange work, thereby improving work efficiency.

[0047] The above description is an explanation of the present invention, not a limitation of the present invention. The present invention may be modified in any form without violating the spirit of the present invention.

Claims

1. A flue gas waste heat recovery process using a flue gas waste heat recovery exchanger, the flue gas waste heat recovery exchanger comprising: - at least one heat exchange unit (1), the upper air outlet (115) and the lower air inlet (114) of two adjacent heat exchange units (1) are connected, the upper smoke exhaust port (112) and the lower smoke inlet (111) are connected via a connecting pipe (5), and the liquid discharge port (113) of each heat exchange unit (1) is connected to the water tank (6); --The air inlet (114) of the frontmost heat exchange unit (1) is connected to the fan (2) through the air supply cover (3), and the air outlet (115) of the rearmost heat exchange unit (1) is connected to the air outlet cover (4); --The heat medium enters the inner cavity of the box (11) from the smoke inlet (111) of the rear heat exchange unit (1), flows along the connecting pipe (5) into the next heat exchange unit (1), and is discharged from the smoke outlet (112) of the front heat exchange unit (1); the cold medium is sent by the fan (2) into the air inlet (114) of the front heat exchange unit (1), flows along the heat exchange pipe (14) to the rear heat exchange unit (1), and is discharged from its air outlet (115); The heat exchange unit (1) comprises: --Box body (11): The box body (11) is provided with a smoke inlet (111) and a smoke outlet (112), an air inlet (114) and an air outlet (115) at both ends, and a liquid discharge outlet (113) at the bottom; --Heat exchange tubes (14): a plurality of heat exchange tubes (14) are arranged in parallel in the box (11) and connect the air inlet (114) and the air outlet (115). The cross section of the heat exchange tubes (14) is rectangular or long runway shaped, and the long central axis thereof is perpendicular to the bottom surface of the box (11); -- End plate (13): arranged at the air inlet (114) and the air outlet (115), the end plate (13) being provided with a plurality of through holes corresponding to the tube openings of the heat exchange tube (14), and the tube openings at both ends of the heat exchange tube (14) being fixed on the through holes of the end plate (13); --Spraying device (15): the spraying device (15) is arranged at the top of the inner cavity of the box body (11); --The cold medium flows in the heat exchange tube (14), and the hot medium flows in the space inside the box (11) and outside the heat exchange tube (14), and the two exchange heat through the tube wall of the heat exchange tube (14); It is characterized by comprising the following steps: --Step I: The refrigerant flows in the heat exchange tube (14) and exchanges heat with the heat medium outside the tube through the tube wall; --Step II: After a period of operation, spraying and soaking are performed in one of the heat exchange units (1) to clean dirt outside the tube wall online; after cleaning, the cleaning liquid is discharged through the drain port (113); --Step III: Continue to perform online cleaning in the next heat exchange unit (1) as in step II. Since each heat exchange unit is independent, it is possible to achieve simultaneous heat exchange, cleaning and drainage functions. After the flue gas enters the next unit from the previous heat exchange unit, the spray pipe of the previous heat exchange unit draws clean water or cleaning liquid from the water tank to spray and flush the heat exchange pipe. After the cleaning is completed, the waste liquid is discharged into the water tank from the drain port, and the remaining heat exchange units continue to perform heat exchange.

2. The flue gas waste heat recovery process according to claim 1, characterized in that: The outer side surface of the end plate (13) is indented from the end surfaces on both sides of the box body (11).

3. The flue gas waste heat recovery process according to claim 1, characterized in that: Flange plates (17) are extended and arranged on the outer periphery of the end surfaces on both sides of the box body (11), and a liquid level meter (16) is installed on the box body (11).

4. The flue gas waste heat recovery process according to claim 1, characterized in that: The connecting pipe (5) is semicircular in shape.

5. The flue gas waste heat recovery process according to claim 1, characterized in that: The liquid level of the cleaning liquid is 1 / 2 to 2 / 3 of the height of the box.

6. The flue gas waste heat recovery process according to claim 1, characterized in that: The spraying takes water from the water tank (6) to achieve water recycling.

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