U-shaped tube heat exchanger suitable for high-dust-content horizontal flue

Abstract

The utility model discloses a U-shaped pipe heat exchanger suitable for a high-dust-content horizontal flue. The U-shaped pipe heat exchanger comprises a shell, an outlet air pipe box, an inlet air pipe box and a heat exchange pipe set. The heat exchange tube set comprises a plurality of U-shaped heat exchange tubes which are vertically arranged and are of an asymmetric structure, a first tube plate is arranged at the top of the shell, the outlet air tube box is arranged above the shell in a covering mode, a second tube plate is arranged in the outlet air tube box, and the inlet air tube box extends into the outlet air tube box and is arranged above the second tube plate in a covering mode. By means of the unique structural design (the U-shaped heat exchange tube of an asymmetric structure), air is preheated before entering the vertical tube box and exchanging heat with high-temperature flue gas, the temperature of the outer wall of the heat exchange tube at the air inlet end in the shell is higher than the dew point temperature of the flue gas, and corrosion and condensation dust accumulation of the heat exchange tube are avoided. Meanwhile, the characteristic of the asymmetric structure of the U-shaped heat exchange pipe is utilized, the preheating cavity and the heat exchange cavity are ingeniously integrated together, and the overall structure of the heat exchanger is very compact.

Description

TECHNICAL FIELD

[0001] The utility model relates to heat exchange equipment technical field, concretely relates to a U -shaped tube heat exchanger suitable for high dust level flue. BACKGROUND

[0002] In order to make full use of high temperature flue gas, air heat exchanger is usually installed in the flue of smelting plant to exchange heat, and there is a kind of high dust flue gas waste heat recovery air heat exchanger placed in high dust flue, which comprises a flue box provided with flue gas inlet and flue gas outlet and a plurality of heat exchange tubes transversely arranged in the flue box, and the two ends of the plurality of heat exchange tubes are fixed on the wall of the flue box through tube plate respectively.This kind of air heat exchanger has the following problems in the process of using: the dust deposited on the outer surface of heat exchange tube is not easy to clean; the expansion stress generated after the heat expansion of heat exchange tube is easy to cause the cracking of tube plate, thereby reducing the service life of heat exchange tube. In order to solve the above technical problems, the air heat exchanger as recorded in reference 1 appears in the prior art:

[0003] Reference 1: Chinese patent document with publication number CN208458520U

[0004] Reference 1 records a kind of high dust flue gas waste heat recovery air heat exchanger, comprising a flue box provided with flue gas inlet and flue gas outlet, a plurality of vertical U-shaped heat exchange tubes are arranged in the flue box, and the gas inlet end and the gas outlet end of the U-shaped heat exchange tube are mounted on the top of the flue box through tube plate. Compared with the prior art, the air heat exchanger can solve the problems of dust accumulation and expansion stress generated after the heat expansion of heat exchange tube in the existing high dust flue gas waste heat recovery air heat exchanger.

[0005] The air heat exchanger in reference 1 can solve the problem that the expansion stress generated after the heat expansion of heat exchange tube is easy to cause the cracking of tube plate, but there are still problems of dew point corrosion of heat exchange tube and dust accumulation on the wall of heat exchange tube. UTILITY MODEL CONTENT

[0006] The utility model aims at solving the above technical problems, and provides a U-shaped tube heat exchanger suitable for high dust horizontal flue.

[0007] In order to solve the above technical problems, the utility model adopts the technical scheme of: a U-shaped tube heat exchanger suitable for high dust horizontal flue, comprising a shell, an outlet air pipe box, an inlet air pipe box and a heat exchange tube group;

[0008] The heat exchange tube group comprises a plurality of vertical U-shaped heat exchange tubes, the U-shaped heat exchange tube comprises a U-shaped bending part and a first straight pipe part and a second straight pipe part connected at both ends thereof, the first straight pipe part and the second straight pipe part are parallel to each other, and the length of the second straight pipe part is greater than that of the first straight pipe part.

[0009] The top of the shell is provided with a first tube plate, and a plurality of groups of tube holes are arranged on the first tube plate, each group of tube holes including a first tube hole for abutting the first straight tube portion of the U-shaped heat exchange tube and a second tube hole for the second straight tube portion to pass through;

[0010] The outlet air pipe box is arranged above the shell, and a second tube plate is arranged in the outlet air pipe box, and a plurality of third tube holes are arranged on the second tube plate in a number corresponding to the groups of heat exchange tubes;

[0011] The U-shaped bending portion of the U-shaped heat exchange tube is arranged in the shell, the first straight tube portion is abutted with the corresponding first tube hole on the first tube plate, and the second straight tube portion passes through the corresponding second tube hole on the first tube plate and is abutted with the third tube hole of the second tube plate;

[0012] The inlet air pipe box is arranged above the second tube plate and extends into the outlet air pipe box, and an air inlet collecting cavity is formed between the inlet air pipe box and the second tube plate, and the U-shaped heat exchange tube is communicated with the air inlet collecting cavity through the port of the second straight tube portion;

[0013] An air outlet collecting cavity is formed between the outlet air pipe box and the first tube plate, and the U-shaped heat exchange tube is communicated with the air outlet collecting cavity through the port of the first straight tube portion;

[0014] The side wall of the shell is respectively provided with a flue gas inlet and a flue gas outlet, the inlet air pipe box is provided with an air inlet, and the outlet air pipe box is provided with an air outlet.

[0015] As a further optimization of the U-shaped tube heat exchanger suitable for the high dust level flue, a dust collecting hopper is arranged below the shell and communicated with the interior of the shell.

[0016] As a further optimization of the U-shaped tube heat exchanger suitable for the high dust level flue, a soot blower is arranged below the groups of heat exchange tubes in the shell.

[0017] As a further optimization of the U-shaped tube heat exchanger suitable for the high dust level flue, the flue gas inlet is arranged on the upper side wall of the shell, and the flue gas outlet is arranged on the lower side wall of the shell.

[0018] As a further optimization of the U-shaped tube heat exchanger suitable for the high dust level flue, the plane where the U-shaped heat exchange tube is arranged is parallel to the axis direction of the flue gas inlet, the groups of heat exchange tubes include a plurality of rows of U-shaped heat exchange tubes distributed along the flue gas flow direction, and the adjacent two rows of U-shaped heat exchange tubes are arranged staggered.

[0019] As a further optimization of the utility model discloses a kind of U-shaped tube heat exchanger suitable for high dust level flue, the plane where U-shaped heat exchange pipe is located and the axis direction of flue gas import is perpendicular to each other, and heat exchange pipe group includes multiple rows of U-shaped heat exchange pipes distributed along the direction of flue gas flow, and the U-shaped heat exchange pipe of adjacent two rows is set with staggered position.

[0020] As a further optimization of the utility model discloses a kind of U-shaped tube heat exchanger suitable for high dust level flue, the plane where U-shaped heat exchange pipe is located and the axis direction of flue gas import is perpendicular to each other, and heat exchange pipe group includes multiple rows of U-shaped heat exchange pipes distributed along the direction of flue gas flow, and the U-shaped heat exchange pipe of adjacent two rows is set with staggered position.

[0021] As a further optimization of the utility model discloses a kind of U-shaped tube heat exchanger suitable for high dust level flue, the plane where U-shaped heat exchange pipe is located and the axis direction of flue gas import is perpendicular to each other, and heat exchange pipe group includes multiple rows of U-shaped heat exchange pipes distributed along the direction of flue gas flow, and the U-shaped heat exchange pipe of adjacent two rows is set with staggered position.

[0022] As a further optimization of the utility model discloses a kind of U-shaped tube heat exchanger suitable for high dust level flue, the plane where U-shaped heat exchange pipe is located and the axis direction of flue gas import is perpendicular to each other, and heat exchange pipe group includes multiple rows of U-shaped heat exchange pipes distributed along the direction of flue gas flow, and the U-shaped heat exchange pipe of adjacent two rows is set with staggered position.

[0023] As a further optimization of the utility model discloses a kind of U-shaped tube heat exchanger suitable for high dust level flue, the plane where U-shaped heat exchange pipe is located and the axis direction of flue gas import is perpendicular to each other, and heat exchange pipe group includes multiple rows of U-shaped heat exchange pipes distributed along the direction of flue gas flow, and the U-shaped heat exchange pipe of adjacent two rows is set with staggered position.

[0024] The utility model has the following beneficial effects: the utility model is through the structure design (the U-shaped heat exchange pipe of asymmetric structure) of uniqueness, air is preheated before entering vertical pipe box and high temperature flue gas heat exchange, makes the heat exchange pipe outer wall temperature of air import end in shell, avoids causing the corrosion and condensation dust of heat exchange pipe.Simultaneously, utilize the characteristic of U-shaped heat exchange pipe asymmetric structure, preheating cavity and heat exchange cavity are ingeniously integrated together, and the overall structure of heat exchanger is very compact. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the overall structure schematic diagram of U-shaped tube heat exchanger in example 1;

[0026] Figure 2 It is the structure schematic diagram of U-shaped heat exchange pipe;

[0027] Figure 3 It is Figure 1 It is the local enlarged schematic view of A in middle;

[0028] Figure 4 It is the schematic diagram of U-shaped tube heat exchanger arrangement mode (form one);

[0029] Figure 5 It is the schematic diagram of U-shaped tube heat exchanger arrangement mode (form two);

[0030] Figure 6 Figure 3 is a schematic diagram of the arrangement of U-tube heat exchangers (Form 3);

[0031] Figure 7 Figure 4 is a schematic diagram of the overall structure of the U-tube heat exchanger of Example 2;

[0032] Markings in the figure:

[0033] 1. Shell;

[0034] 2. Outlet air pipe box;

[0035] 3. Inlet air pipe box;

[0036] 4. U-shaped heat exchange pipe;

[0037] 401. First straight pipe section;

[0038] 402. Second straight pipe section;

[0039] 403. U-shaped curved section;

[0040] 5. First pipe plate;

[0041] 6. First pipe hole;

[0042] 7. Second pipe hole;

[0043] 8. Second pipe plate;

[0044] 9. Third pipe hole;

[0045] 10. Ash hopper;

[0046] 11. Ash blower. DETAILED DESCRIPTION

[0047] In order to better understand the present application, the content of the present application will be further illustrated below in combination with examples, but the content of the present application is not limited to the following examples.

[0048] <Example 1>

[0049] As shown in Figure 1 and 3 , a U-tube heat exchanger applied to a heat exchange system in the field of high-dust industrial flue gas waste heat recovery. The U-tube heat exchanger comprises a shell 1, an outlet air pipe box 2, an inlet air pipe box 3, and a heat exchange pipe group.

[0050] The heat exchange pipe group comprises a plurality of vertically arranged U-shaped heat exchange pipes 4. As shown in Figure 2As shown, the U-shaped heat exchange pipe 4 includes a U-shaped bending part 403 and a first straight pipe part 401 and a second straight pipe part 402 connected at both ends thereof, the first straight pipe part 401 and the second straight pipe part 402 are parallel to each other and the length of the second straight pipe part 402 is greater than that of the first straight pipe part 401, forming an asymmetric structure. Specifically, the second straight pipe part 402 and the first straight pipe part 401 have a port height difference ΔH≥1.0m (preferably ΔH=1.5m), it should be noted that the specific height difference is determined according to the actual working condition, and should have sufficient height difference to meet the requirement of air preheating.

[0051] The heat exchange pipe is manufactured by high-frequency welding process, and the material is 0Cr18Ni10Ti stainless steel which is resistant to high temperature corrosion. The shell 1, the outlet air pipe box 2 and the inlet air pipe box 3 are all made of Q345R low alloy high strength steel.

[0052] The top of the shell 1 is provided with a first tube plate 5. Specifically, the top of the shell 1 is provided with an opening, and the first tube plate 5 is arranged at the opening. The first tube plate 5 is provided with a plurality of groups of tube holes corresponding to the heat exchange pipe groups, each group of tube holes includes a first tube hole 6 for abutting the first straight pipe part 401 of the U-shaped heat exchange pipe 4 and a second tube hole 7 for the second straight pipe part 402 to pass through.

[0053] The outlet air pipe box 2 is a box with an open lower end, and the top thereof is a sloping top structure, that is, it has two side walls with different heights, and the air outlet is arranged on the higher side wall. The sloping top of the outlet air pipe box 2 is provided with a through hole for the inlet air pipe box 3 to extend into.

[0054] The outlet air pipe box 2 is arranged above the shell 1 and covers the first tube plate 5 completely. The second tube plate 8 is arranged in the outlet air pipe box 2, and the second tube plate 8 is provided with a plurality of third tube holes 9 corresponding to the heat exchange pipe groups.

[0055] The U-shaped bending part 403 of the U-shaped heat exchange pipe 4 is arranged in the shell 1, the port of the first straight pipe part 401 of the U-shaped heat exchange pipe 4 is abutted with the corresponding first tube hole 6 of the first tube plate 5, and the second straight pipe part 402 passes through the corresponding second tube hole 7 of the first tube plate 5 and is abutted with the third tube hole 9 of the second tube plate 8.

[0056] In order to better avoid the generation of dust, the arrangement form of the heat exchange pipe can be optimized in the following three forms:

[0057] The first form: as shown in the figure, Figure 4 The plane where the U-shaped heat exchange pipe 4 is located is parallel to the axis direction of the flue gas inlet, and the heat exchange pipe group includes a plurality of rows of U-shaped heat exchange pipes 4 distributed along the flue gas flow direction, and the adjacent two rows of U-shaped heat exchange pipes 4 are arranged staggered.

[0058] The second form: as shown in the figure, Figure 6As shown, the plane of the U-shaped heat exchange tube 4 is perpendicular to the axis direction of the flue gas inlet, and the heat exchange tube group includes multiple rows of U-shaped heat exchange tubes 4 distributed along the flue gas flow direction, and the adjacent two rows of U-shaped heat exchange tubes 4 are staggered.

[0059] The third form: as shown in Figure 5 As shown, the plane of the U-shaped heat exchange tube 4 has an angle with the axis direction of the flue gas inlet, and the heat exchange tube group includes multiple rows of U-shaped heat exchange tubes 4 distributed along the flue gas flow direction.

[0060] The adjacent two rows of U-shaped heat exchange tubes are staggered, forcing the flue gas to frequently change direction when flowing through the tube bundle, significantly increasing the turbulence intensity. The high disturbance characteristics of the turbulent flow destroy the formation of the laminar boundary layer, reducing the opportunity for particles to deposit on the tube wall. At the same time, the vortex in the turbulent flow can wash away the particles that have adhered to the surface. The complex flow path of the staggered arrangement increases the tortuosity of the particle migration path with the fluid. Larger particles may be detached from the flow line due to inertia, but the staggered structure reduces the probability of particles directly impacting the tube wall by dispersing the impact angle, thereby reducing the adhesion of flue gas particles.

[0061] The inlet air pipe box 3 is an open box at the lower end, and the top is a sloping top structure, that is, it has two side walls with different heights, and the air inlet is arranged on the higher side wall, and the lower side wall end is inserted into the outlet air pipe box 2 and covers the second tube plate 8.

[0062] The air entering horizontally from the side wall will gradually flow downward under the guidance of the sloping top, so that the airflow can be more evenly distributed above the heat exchange tube, avoiding the concentration of airflow in a certain area.

[0063] The air inlet collection cavity is formed between the inlet air pipe box 3 and the second tube plate 8, and the U-shaped heat exchange tube 4 is communicated with the air inlet collection cavity through the port of the second straight pipe part 402.

[0064] The air outlet collection cavity is formed between the outlet air pipe box 2 and the first tube plate 5, and the U-shaped heat exchange tube 4 is communicated with the air outlet collection cavity through the port of the first straight pipe part 401.

[0065] The side wall of the shell 1 is respectively provided with a flue gas inlet and a flue gas outlet. The flue gas inlet and the flue gas outlet are located at the same horizontal position, and the flue gas flows horizontally.

[0066] The preheating cavity is formed between the first tube plate 5 and the second tube plate 8, and in the preheating cavity, the air entering from the port of the second straight pipe part 402 exchanges heat with the air outside the tube (after heat exchange with the flue gas), which plays a preheating role. The preheated air exchanges heat with the high-temperature flue gas outside the tube in the shell 1, and then exchanges heat with the low-temperature air entering the second straight pipe part 402 of the heat exchange tube, and then is discharged from the heat exchanger.

[0067] Through the unique structure design (the U-shaped heat exchange pipe of asymmetric structure), the air is preheated before entering the vertical pipe box and the high-temperature flue gas heat exchange, so that the outer wall temperature of the heat exchange pipe at the air inlet end in the shell is higher than the dew point temperature of the flue gas, and the corrosion and condensation of the heat exchange pipe are avoided. At the same time, the preheating cavity and the heat exchange cavity are ingeniously integrated by using the asymmetric structure of the U-shaped heat exchange pipe, and the overall structure of the heat exchanger is very compact.

[0068] <Embodiment 2>

[0069] As shown in Figure 7 The overall structure of the present embodiment is the same as that of <Embodiment 1>, and the difference lies in that the flue gas inlet is arranged at the upper side wall of the shell 1, and the flue gas outlet is arranged at the lower side wall of the shell 1. In the present embodiment, the flue gas flows upward and downward. At the same time, a soot blower 11 is arranged below the heat exchange pipe group in the shell 1. Through the soot blower 11, the ash particles attached to the heat exchange pipe can be blown down and discharged from the heat exchanger through the ash collecting hopper 10. The soot blower 11 can adopt a sonic soot blower, which is usually composed of a gas source (compressed air or nitrogen), a sonic generator (diaphragm type or rotary whistle type), a control system and the like. The accumulated ash particles are loosened by the sonic vibration (the frequency is usually 100-2000 Hz), and then fall into the ash collecting hopper 10 and are discharged from the heat exchanger.

[0070] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application.

Claims

1. A U-tube heat exchanger suitable for use in flues having high dust levels, characterised in that: The heat exchanger comprises a shell (1), an outlet air pipe box (2), an inlet air pipe box (3) and a heat exchange pipe group; The heat exchange pipe group comprises a plurality of vertically arranged U-shaped heat exchange pipes (4), each of which comprises a U-shaped bending part (403) and first and second straight pipe parts (401, 402) connected at two ends of the U-shaped bending part (403), the first and second straight pipe parts (401, 402) are parallel to each other, and the length of the second straight pipe part (402) is greater than that of the first straight pipe part (401). A first pipe plate (5) is arranged at the top of the shell (1), and a plurality of groups of pipe holes are arranged on the first pipe plate (5), each group of pipe holes comprises a first pipe hole (6) for abutting against the first straight pipe part (401) of the U-shaped heat exchange pipe (4) and a second pipe hole (7) for the second straight pipe part (402) to pass through. The outlet air pipe box (2) is arranged above the shell (1), and a second pipe plate (8) is arranged in the outlet air pipe box (2), a plurality of third pipe holes (9) are arranged on the second pipe plate (8), and the number of the third pipe holes (9) is consistent with that of the heat exchange pipe group. The U-shaped bending part (403) of the U-shaped heat exchange pipe (4) is arranged in the shell (1), the first straight pipe part (401) of the U-shaped heat exchange pipe (4) is abutted against the corresponding first pipe hole (6) on the first pipe plate (5), and the second straight pipe part (402) passes through the corresponding second pipe hole (7) on the first pipe plate (5) and is abutted against the third pipe hole (9) of the second pipe plate (8). The inlet air pipe box (3) extends into the outlet air pipe box (2) and is arranged above the second pipe plate (8), an air inlet collection cavity is formed between the inlet air pipe box (3) and the second pipe plate (8), and the U-shaped heat exchange pipe (4) is communicated with the air inlet collection cavity through the port of the second straight pipe part (402). The outlet air pipe box (2) and the first pipe plate (5) form an air outlet collection cavity, and the U-shaped heat exchange pipe (4) is communicated with the air outlet collection cavity through the port of the first straight pipe part (401). The side wall of the shell (1) is respectively provided with a flue gas inlet and a flue gas outlet, the inlet air pipe box (3) is provided with an air inlet, and the outlet air pipe box (2) is provided with an air outlet.

2. A U-tube heat exchanger suitable for use in flues having high dust levels as claimed in claim 1 wherein: A dust collecting hopper (10) is arranged below the shell (1) and communicated with the interior of the shell (1).

3. A U-tube heat exchanger suitable for use in flues having high dust levels as claimed in claim 2 wherein: A soot blower (11) is arranged below the heat exchange pipe group in the shell (1).

4. The U-tube heat exchanger suitable for use in flue having high dust level according to claim 1, wherein: The flue gas inlet is arranged on the upper side wall of the shell (1), and the flue gas outlet is arranged on the lower side wall of the shell (1).

5. A U-tube heat exchanger suitable for use in flues having high dust levels as claimed in claim 4 wherein: The plane where the U-shaped heat exchange pipe (4) is arranged is parallel to the axis direction of the flue gas inlet, the heat exchange pipe group comprises a plurality of rows of U-shaped heat exchange pipes (4) arranged along the flue gas flow direction, and adjacent two rows of U-shaped heat exchange pipes (4) are arranged staggeredly.

6. The U-tube heat exchanger suitable for use in flues with high dust levels as claimed in claim 1 wherein: The plane where the U-shaped heat exchange pipe (4) is arranged is perpendicular to the axis direction of the flue gas inlet, the heat exchange pipe group comprises a plurality of rows of U-shaped heat exchange pipes (4) arranged along the flue gas flow direction, and adjacent two rows of U-shaped heat exchange pipes (4) are arranged staggeredly.

7. The U-tube heat exchanger suitable for use in flue having high dust level according to claim 1, wherein: The plane where the U-shaped heat exchange pipe (4) is arranged has an included angle with the axis direction of the flue gas inlet, and the heat exchange pipe group comprises a plurality of rows of U-shaped heat exchange pipes (4) arranged along the flue gas flow direction.

8. The U-tube heat exchanger suitable for use in flue having high dust level according to claim 1, wherein: The outlet air pipe box (2) is a sloping roof structure, the sloping roof of the outlet air pipe box (2) is provided with a through hole for the inlet air pipe box (3) to extend into, and the air outlet is arranged on the side wall of the outlet air pipe box (2).

9. A U-tube heat exchanger suitable for use in flues having high dust levels according to claim 8, characterised in that: The inlet air pipe box (3) is a sloping roof structure, and the air inlet is arranged on the side wall of the inlet air pipe box (3).

10. The U-tube heat exchanger suitable for use in flues with high dust levels as claimed in claim 1 wherein: The height difference between the port of the first straight pipe part (401) of the U-shaped heat exchange pipe (4) and the port of the second straight pipe part (402) is greater than 1m.

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