Low-temperature flue gas heat exchange device

Abstract

The utility model discloses a low-temperature flue gas heat exchange device which comprises a first-stage preheater and a second-stage preheater, and the first-stage preheater comprises a second inlet device, a second heat exchange pipe and a second outlet device; the secondary preheater comprises a first inlet device, a first heat exchange tube and a first outlet device; the first outlet device communicates with the second inlet device through a connecting pipe, the first inlet device feeds a working medium in a heat exchange system pipeline into the first outlet device through the first heat exchange pipe, and the first outlet device feeds the heated working medium into the second inlet device through the connecting pipe. The heat exchanger has the beneficial effects that flue gas enters from the flue gas inlet in the left end of the first-stage preheater and is exhausted from the flue gas outlet in the right end of the second-stage preheater after heat exchange is completed, the heat exchanger can be conveniently used in a pressed heat exchanger system in a set mode, the heat exchange efficiency is improved through countercurrent flow heat exchange, the heat exchange efficiency is improved, and the heat exchange efficiency is improved. And the long-term operation stability of the equipment is good.

Description

Technical Field

[0001] The utility model relates to the field of waste heat recovery, and in particular to a low-temperature flue gas heat exchange device. Background Art

[0002] In order to make full use of the waste heat in the flue gas, reduce energy consumption and improve energy efficiency, low-temperature flue gas heat exchange devices came into being.

[0003] Traditional low-temperature flue gas heat exchange devices usually use shell and tube heat exchangers, which have low heat transfer efficiency and are easily affected by corrosion and dust accumulation. In addition, traditional low-temperature flue gas heat exchange devices also have problems such as large floor space and high maintenance costs.

[0004] However, the existing low-temperature flue gas heat exchange device also has the following problems:

[0005] It is inconvenient to use as a complete set in a pressurized heat exchanger system, the heat exchange efficiency is low, and the long-term operating stability of the equipment is poor. Utility Model Content

[0006] The utility model aims to provide a low-temperature flue gas heat exchange device to solve the problems that the above-mentioned heat exchange device is inconvenient to be used as a complete set in a pressurized heat exchanger system, the heat exchange efficiency is low, and the long-term operation stability of the equipment is poor.

[0007] In order to solve the above technical problems, the utility model provides a low-temperature flue gas heat exchange device, which includes a primary preheater and a secondary preheater, the left end of the primary preheater is a flue gas inlet, the right end of the secondary preheater is a flue gas outlet, the primary preheater includes a second inlet device, a second heat exchange pipe and a second outlet device; the secondary preheater includes a first inlet device, a first heat exchange pipe and a first outlet device; the primary preheater is connected with the secondary preheater through a connecting flue, the first outlet device is connected with the second inlet device through a connecting pipe, the first inlet device sends the working fluid in the heat exchange system pipeline into the first outlet device through the first heat exchange pipe, the first outlet device sends the heated working fluid into the second inlet device through the connecting pipe, the second inlet device sends the working fluid into the second outlet device through the second heat exchange pipe, and the second outlet device sends the working fluid into the process system pipeline.

[0008] Further, the second inlet device includes a second inlet distribution header and a second inlet header, the second outlet device includes a second outlet distribution header and an outlet manifold, the first inlet device includes a first distribution header and a first inlet distribution header, and the first outlet device includes a first outlet header and a first outlet distribution header.

[0009] Furthermore, the second heat exchange tube and the first heat exchange tube are both industrial high-efficiency tubes, and a plurality of pits are radially punched on the outside of the tube body of the industrial high-efficiency tube. The pits on any cross section of the industrial high-efficiency tube are evenly arranged, and adjacent pits in the axial direction of the industrial high-efficiency tube are staggered; the tube wall of the industrial high-efficiency tube has uniform thickness.

[0010] Furthermore, a plurality of supporting baffles are vertically arranged between a plurality of the second heat exchange tubes, and a plurality of supporting baffles are vertically arranged between a plurality of the first heat exchange tubes.

[0011] Furthermore, a support guard plate is provided on the side of the first-stage preheater, and a support guard plate is provided on the side of the second-stage preheater.

[0012] Furthermore, a soot blowing device is arranged in the connecting flue.

[0013] Furthermore, a header support frame is provided below the outlet header.

[0014] Furthermore, a transverse pitch between the first heat exchange tube and the second heat exchange tube is 76 mm, and a longitudinal pitch between the first heat exchange tube and the second heat exchange tube is 72 mm.

[0015] The beneficial effects of the utility model are as follows: compared with the prior art, a low-temperature flue gas heat exchange device, a working medium from a system pipeline enters a first inlet header via a first distribution header, enters a first outlet distribution header from a first outlet header after being heated by a first heat exchange tube, and sends the heated working medium to a connecting pipe, on which a vent and a safety valve are provided to ensure safe and stable operation of the equipment, and the working medium is introduced into a second inlet distribution header from the connecting pipe, the second inlet distribution header is connected with the second inlet header, and is led out from the second outlet distribution header after heat exchange by the second heat exchange tube, and finally sent into the process system pipeline by the outlet header, the flue gas enters from the flue gas inlet at the left end of the first-stage preheater, and is discharged from the flue gas outlet at the right end of the second-stage preheater after the heat exchange is completed, which is convenient for complete use in a pressurized heat exchanger system, and the heat exchange efficiency is improved by countercurrent heat exchange, and the long-term operation stability of the equipment is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the main structure of a low-temperature flue gas heat exchange device.

[0017] Figure 2 The figure is a schematic diagram of the top view of the structure of a low-temperature flue gas heat exchange device.

[0018] Figure 3 It is a left-side structural schematic diagram of a low-temperature flue gas heat exchange device.

[0019] Wherein: 1. primary preheater; 11. second inlet distribution header; 12. second inlet header; 13. second heat exchange tube; 14. second outlet distribution header; 15. outlet header; 2. secondary preheater; 21. first distribution header; 22. first inlet header; 23. first heat exchange tube; 24. first outlet header; 25. first outlet distribution header; 3. supporting partition; 4. supporting guard plate; 5. connecting pipe; 6. connecting flue; 7. flue gas inlet; 8. flue gas outlet; 16. second outlet device; 17. first inlet device; 18. first outlet device; 19. industrial high-efficiency tube; 201. support; 202. header support frame; 204. soot blowing device; 205. second inlet device. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiment is only one embodiment of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the utility model.

[0021] In order to make the objectives, technical solutions and advantages of the present application more clear, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0022] In the following description, references to "one embodiment", "an embodiment", "an example", "an example", etc. indicate that the embodiment or example described in this way may include specific features, structures, characteristics, properties, elements or limitations, but not every embodiment or example necessarily includes the specific features, structures, characteristics, properties, elements or limitations. In addition, repeated use of the phrase "according to one embodiment of the present application" may refer to the same embodiment, but does not necessarily refer to the same embodiment.

[0023] like Figure 1As shown, a low-temperature flue gas heat exchange device includes a primary preheater 1 and a secondary preheater 2. The left end of the primary preheater 1 is a flue gas inlet 7, and the right end of the secondary preheater 2 is a flue gas outlet 8. The primary preheater 1 includes a second inlet device 205, a second heat exchange pipe 13, and a second outlet device 16; the secondary preheater 2 includes a first inlet device 17, a first heat exchange pipe 23, and a first outlet device 18; the primary preheater 1 is connected to the secondary preheater 2 through a connecting flue 6, and the first outlet device 18 is connected to the second inlet device 205. The first inlet device 17 is connected through the connecting pipe 5, and the working medium in the heat exchange system pipeline is sent to the first outlet device 18 through the first heat exchange pipe 23. The first outlet device 18 sends the heated working medium to the second inlet device 205 through the connecting pipe 5. The second inlet device 205 sends the working medium to the second outlet device 16 through the second heat exchange pipe 13. The second outlet device 16 sends the working medium into the process system pipeline. The countercurrent of the low-temperature flue gas and the working medium can ensure that the temperature of the low-temperature flue gas is close to the temperature of the working medium, which makes the average temperature difference larger, thereby improving the heat transfer efficiency.

[0024] The second inlet device 205 includes a second inlet distribution header 11 and a second inlet header 12, the second outlet device 16 includes a second outlet distribution header 14 and an outlet manifold 15, the first inlet device 17 includes a first distribution header 21 and a first inlet distribution header, the first outlet device 18 includes a first outlet header 24 and a first outlet distribution header 25, the working fluid from the system pipeline enters the first inlet header 22 via the first distribution header 21, enters the first outlet distribution header 25 from the first outlet header 24 after being heated by the first heat exchange tube 23, and the heated working fluid is sent to the connecting pipe 5, which is provided with a vent and a safety valve to ensure safe and stable operation of the equipment, and the working fluid is introduced into the second inlet distribution header 11 from the connecting pipe 5, the second inlet distribution header 11 is connected to the second inlet header 12, and is led out from the second outlet distribution header 14 after heat exchange in the second heat exchange tube 13, and finally sent to the process system pipeline by the outlet manifold 15 to ensure uniform and reasonable distribution of the working fluid.

[0025] The second heat exchange tube 13 and the first heat exchange tube 23 both use industrial high-efficiency tubes 19. Several pits are radially punched on the outside of the tube body of the industrial high-efficiency tube 19. The pits on any cross section of the industrial high-efficiency tube 19 are evenly arranged, and adjacent pits in the axial direction of the industrial high-efficiency tube 19 are staggered. The tube wall of the industrial high-efficiency tube 19 has uniform thickness. On the basis of not changing the heat exchange space of the device, the heat exchange area is increased, the scaling rate is reduced, and the heat exchange efficiency is increased. The shape of the inner cavity wall causes the heat exchange fluid to form turbulence in the pipeline, which has a significant flushing effect on the tube wall, and the inner wall is difficult to scale, which avoids the situation where scaling reduces the heat transfer efficiency as the use time increases. At the same time, the industrial high-efficiency tube 19 is made of duplex stainless steel to prevent the industrial high-efficiency tube 19 from tube bundle corrosion in the low-temperature flue gas of the chemical industry.

[0026] A sootblower 204 bracket 13 is provided in the connecting flue 6, and a sootblower 204 is provided on the sootblower 204 bracket 13. This device is mainly used for waste heat recovery of low-temperature flue gas in the chemical industry. During the heat exchange process, because of the dusty and corrosive low-temperature flue gas, ash is easily deposited on the industrial high-efficiency pipe 19 due to the low-temperature flue gas being at the dew point temperature. It is necessary to provide a sootblower 204 in the connecting flue 6 for cleaning to ensure the heat exchange efficiency of the device and prevent the corrosive low-temperature flue gas from further corroding the industrial high-efficiency pipe 19.

[0027] A header support frame 202 is disposed below the outlet header 15 to provide support for the outlet header 15 and facilitate the docking and installation of the outlet header 15 and the system process system pipeline.

[0028] A support guard plate 4 is provided on the side of the first-stage preheater 1, a support 201 is provided at the lower end of the first-stage preheater 1, a support guard plate 4 is provided on the side of the second-stage preheater 2, and a support 201 is provided under the second-stage preheater 2 to ensure the strength of the device, improve the pressure-bearing capacity of the device, and ensure the continuous and stable operation of the entire device.

[0029] The transverse pitch between the first heat exchange tube 23 and the second heat exchange tube 13 is 76 mm, and the longitudinal pitch between the first heat exchange tube 23 and the second heat exchange tube 13 is 72 mm. For the industrial high-efficiency tube 19, this pitch setting can improve the flow state of the fluid in the device, reduce fluid resistance, and improve heat exchange efficiency. Three supporting partitions 3 are vertically arranged at equal intervals between the first heat exchange tubes 23, and three supporting partitions 3 are vertically arranged at equal intervals between the second heat exchange tubes 13. The first heat exchange tube 23 and the second heat exchange tube 13 are separated and supported by the supporting partitions 3 to reduce the overall vibration of the module, making the module structure more reasonable and higher in heat exchange efficiency.

[0030] The heat exchange device is modularized and shipped from the factory. The modules are connected on site with connecting pipes 5, which is more suitable for complete use in a pressurized heat exchanger system to achieve gas-water heat exchange and continuous and stable operation under the condition of low-temperature flue gas waste heat recovery in the chemical industry.

[0031] Working process: the working medium from the system pipeline enters the first inlet header 22 through the first distribution header 21, enters the first outlet distribution header 25 from the first outlet header 24 after being heated by the first heat exchange tube 23, and sends the heated working medium to the connecting pipe 5. The connecting pipe 5 is provided with a vent and a safety valve to ensure the safe and stable operation of the equipment. The working medium is introduced into the second inlet distribution header 11 from the connecting pipe 5. The second inlet distribution header 11 is connected with the second inlet header 12. After heat exchange in the second heat exchange tube 13, it is led out from the second outlet distribution header 14 and finally sent into the process system pipeline by the outlet header 15. The flue gas enters from the flue gas inlet 7 at the left end of the first preheater 1, and is discharged from the flue gas outlet 8 at the right end of the second preheater 2 after the heat exchange is completed. The soot blowing device 204 is used in the connecting flue 6 to clean the ash accumulated on the industrial high-efficiency tube 19.

[0032] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-temperature flue gas heat exchange device, characterized in that: It includes a primary preheater and a secondary preheater, the left end of the primary preheater is a flue gas inlet, the right end of the secondary preheater is a flue gas outlet, the primary preheater includes a second inlet device, a second heat exchange pipe and a second outlet device; the secondary preheater includes a first inlet device, a first heat exchange pipe and a first outlet device; the primary preheater is connected with the secondary preheater through a connecting flue, the first outlet device is connected with the second inlet device through a connecting pipe, the first inlet device sends the working fluid in the heat exchange system pipeline into the first outlet device through the first heat exchange pipe, the first outlet device sends the heated working fluid into the second inlet device through the connecting pipe, the second inlet device sends the working fluid into the second outlet device through the second heat exchange pipe, and the second outlet device sends the working fluid into the process system pipeline.

2. A low-temperature flue gas heat exchange device according to claim 1, characterized in that: The second inlet device includes a second inlet distribution header and a second inlet header, the second outlet device includes a second outlet distribution header and an outlet header, the first inlet device includes a first distribution header and a first inlet distribution header, and the first outlet device includes a first outlet header and a first outlet distribution header.

3. A low-temperature flue gas heat exchange device according to claim 1, characterized in that: The second heat exchange tube and the first heat exchange tube are both industrial high-efficiency tubes, and a plurality of pits are radially punched on the outside of the tube body of the industrial high-efficiency tube. The pits on any cross section of the industrial high-efficiency tube are evenly arranged, and adjacent pits in the axial direction of the industrial high-efficiency tube are staggered; the tube wall of the industrial high-efficiency tube has uniform thickness.

4. A low-temperature flue gas heat exchange device according to claim 1, characterized in that: A plurality of supporting baffles are vertically arranged between a plurality of the second heat exchange tubes, and a plurality of supporting baffles are vertically arranged between a plurality of the first heat exchange tubes.

5. The low-temperature flue gas heat exchange device according to claim 1, characterized in that: A supporting guard plate is provided on the side of the first-stage preheater, and a supporting guard plate is provided on the side of the second-stage preheater.

6. A low-temperature flue gas heat exchange device according to claim 1, characterized in that: A soot blowing device is arranged in the connecting flue.

7. A low-temperature flue gas heat exchange device according to claim 2, characterized in that: A header support frame is arranged below the outlet header.

8. The low-temperature flue gas heat exchange device according to claim 1, characterized in that: The transverse pitch between the first heat exchange tube and the second heat exchange tube is 76 mm, and the longitudinal pitch between the first heat exchange tube and the second heat exchange tube is 72 mm.

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