A low-temperature flue gas online heat extraction device and method

Abstract

The application discloses a low-temperature flue gas on-line heat taking device and method, relates to the technical field of flue gas waste heat recovery, and the device comprises flue gas pipelines before and after heat taking, a first variable diameter section, a working cabin, a second variable diameter section and flue gas pipelines after heat releasing which are sequentially connected, a maintenance cabin, an electric gate valve, a flue gas heat exchanger and a sealing assembly, the maintenance cabin is installed on one side of the working cabin, the maintenance cabin is communicated with the working cabin, the electric gate valve is installed at the connection of the working cabin and the maintenance cabin, the flue gas heat exchanger is movably arranged, the flue gas heat exchanger is arranged in the working cabin or the maintenance cabin, and the sealing assembly is used for sealing the gap between the flue gas heat exchanger and the inner wall of the working cabin under the condition that the flue gas heat exchanger is arranged in the working cabin. When maintenance and repair are carried out, a bypass flue and a cut-off valve are not needed, cost and land occupation are saved, air leakage hidden dangers existing in the cut-off valve are eliminated, the maintenance space is sufficient, high safety guarantee is provided, and the fan energy consumption of the flue gas system is reduced.

Description

Technical Field

[0001] This invention relates to the field of flue gas waste heat recovery technology, and in particular to a low-temperature flue gas online heat extraction device and method. Background Technology

[0002] Low-temperature flue gas heat exchangers have the technical advantage of recovering low-temperature heat energy, but they also have the characteristics of large heat exchange area and high flue gas resistance. If the flue gas is not clean, it is easy to cause ash accumulation, blockage or even corrosion inside the heat exchanger, resulting in a high failure rate. Therefore, the workload of inspection and maintenance during the use of low-temperature flue gas heat exchangers is relatively large.

[0003] To ensure that maintenance does not affect the operation of the main production system, the usual practice is to install a bypass flue gas pipeline. However, this inevitably increases the resistance of the flue gas system. Moreover, the flue gas pipeline has a large diameter, making it difficult to install a bypass flue gas pipeline when space is limited. Even if it is installed, the risk of leakage from the shut-off valve poses a significant threat to personnel during maintenance. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a low-temperature flue gas online heat extraction device and method.

[0005] This application provides a low-temperature flue gas online heat extraction device, including a pre-heat extraction flue gas duct, a first diameter-changing section, a working chamber, a second diameter-changing section, a post-heat release flue gas duct, a maintenance chamber, an electric gate valve, a flue gas heat exchanger, and a sealing assembly. The pre-heat extraction flue gas duct, the first diameter-changing section, the working chamber, the second diameter-changing section, and the post-heat release flue gas duct are connected in sequence. The maintenance chamber is installed on one side of the working chamber and is connected to the working chamber. The electric gate valve is installed at the connection between the working chamber and the maintenance chamber. The flue gas heat exchanger is movably installed and can be located in the working chamber or the maintenance chamber. The sealing assembly seals the gap between the flue gas heat exchanger and the inner wall of the working chamber when the flue gas heat exchanger is located in the working chamber.

[0006] In some embodiments, the sealing assembly includes four single-leaf sealing valves and a limiting block installed outside the flue gas heat exchanger. The four single-leaf sealing valves are respectively installed on four sides of a cross section perpendicular to the airflow direction inside the working chamber. Two of the four single-leaf sealing valves are arranged vertically and the other two are arranged horizontally. The limiting block is equipped with a flexible sealing strip. Under the condition that the valve plate of the single-leaf sealing valve abuts against the flexible sealing strip on the limiting block, the sealing assembly seals the gap between the flue gas heat exchanger and the inner wall of the working chamber.

[0007] In some embodiments, the bottom of the working compartment and the bottom of the maintenance compartment are provided with a track, and the bottom of the flue gas heat exchanger is equipped with a moving wheel, which is movably mounted on the track; the low-temperature flue gas online heat extraction device includes a drive mechanism to control the movement of the flue gas heat exchanger on the track.

[0008] In some implementations, a limiting mechanism is installed on the track to facilitate the smooth movement of the flue gas heat exchanger to a predetermined position within the working chamber.

[0009] In some embodiments, the bottom of the valve plate of the electric gate valve is provided with a groove, and the track passes through the groove when the electric gate valve cuts off the connection between the working chamber and the maintenance chamber.

[0010] In some implementations, the maintenance compartment is equipped with a movable maintenance door, which is fitted with an observation window.

[0011] In some implementations, a medium connection pipe is installed on one side of the flue gas heat exchanger, and a sleeve flange is installed on the side of the working chamber away from the maintenance chamber. When the flue gas heat exchanger is inside the working chamber, the medium connection pipe passes through the sleeve flange and connects to the medium pipeline network outside the working chamber.

[0012] In some implementations, the sleeve flange is equipped with a blind flange that seals the sleeve flange when the flue gas heat exchanger is removed from the working chamber.

[0013] In some implementations, the single-leaf sealing valve is configured to be electrically or manually controlled.

[0014] A method for online heat extraction from low-temperature flue gas, using the aforementioned online heat extraction device for low-temperature flue gas, includes the following steps: The flue gas heat exchanger is positioned within a working chamber; an electric gate valve is closed; a sealing assembly seals the gap between the flue gas heat exchanger and the inner wall of the working chamber, allowing the flue gas heat exchanger to exchange heat with the flue gas; when the flue gas heat exchanger requires inspection or maintenance, the sealing assembly is released from the gap between the flue gas heat exchanger and the inner wall of the working chamber, the electric gate valve is opened, and the flue gas heat exchanger is moved from the working chamber to the maintenance chamber; after the flue gas heat exchanger has been moved to the maintenance chamber, the electric gate valve is closed, the maintenance chamber is opened, and the flue gas heat exchanger is inspected or maintained.

[0015] The beneficial effects of this application are as follows: It provides a low-temperature flue gas online heat extraction device, comprising a pre-heat extraction flue gas duct, a first diameter-changing section, a working chamber, a second diameter-changing section, and a post-heat release flue gas duct connected in sequence. A maintenance chamber is connected to one side of the working chamber. An electric gate valve is installed at the connection between the working chamber and the maintenance chamber. A flue gas heat exchanger is movably installed in both the working chamber and the maintenance chamber. When the flue gas heat exchanger is in the working chamber for heat exchange, a sealing assembly seals the gap between the flue gas heat exchanger and the inner wall of the working chamber. When the flue gas heat exchanger needs maintenance or repair, the electric gate valve is opened, the sealing assembly is loosened, and the flue gas heat exchanger is transferred to the maintenance chamber. After maintenance or repair is completed, it returns to the working chamber. The low-temperature flue gas online heat extraction device provided above allows for convenient maintenance and repair. During maintenance, there is no need to install bypass flues and shut-off valves, saving costs and space, and eliminating the risk of leakage associated with shut-off valves. This device moves the flue gas heat exchanger to the maintenance chamber for inspection or maintenance. The maintenance chamber is completely separated from the flue gas, and the maintenance space is ample, providing a high level of safety. Furthermore, during the inspection or maintenance process, the flue gas heat exchanger leaves the working chamber, meaning it is completely separated from the flue gas passage, thereby reducing the resistance of the flue gas system and the energy consumption of the flue gas system's fans. On the other hand, it also reduces the accumulation of ash and wear on the flue gas heat exchanger. By setting up the first and second diameter-changing sections, the size matching requirements between the pipeline and the working chamber are solved, and the problem of flue gas leakage is avoided through the sealing components, forming a single flue gas path through the flue gas heat exchanger. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0017] Figure 1 A top view of a low-temperature flue gas online heat extraction device provided in this application;

[0018] Figure 2 A front view of a low-temperature flue gas online heat exchange device provided in this application;

[0019] Figure 3 A schematic diagram showing the working position of the flue gas heat exchanger in a low-temperature flue gas online heat extraction device provided in this application;

[0020] Figure 4 A schematic diagram showing the movement of the flue gas heat exchanger from the working chamber to the maintenance chamber in a low-temperature flue gas online heat extraction device provided in this application;

[0021] Figure 5 A schematic diagram showing the location of the flue gas heat exchanger under maintenance in a low-temperature flue gas online heat extraction device provided in this application;

[0022] Figure 6 for Figure 1 A magnified view of a section at point A in the middle;

[0023] Figure 7 for Figure 2 A magnified view of a section at point B in the middle;

[0024] Figure 8 for Figure 2 A magnified view of a section at point C.

[0025] Attached diagram labels: 1-Preheating flue gas duct, 2-First diameter change section, 3-Working chamber, 4-Flue gas heat exchanger, 5-Second diameter change section, 6-Postheating flue gas duct, 7-Electric gate valve, 8-Maintenance chamber, 9-Railway, 10-Gate valve actuator, 11-Maintenance door, 12-Media connection pipe, 13-Casing flange, 14-Moving wheel, 15-Single leaf sealing valve, 16-Observation window, 17-Limit block, 18-Flexible sealing strip. Detailed Implementation

[0026] Example 1

[0027] This embodiment discloses a low-temperature flue gas online heat extraction device. Please refer to... Figure 1 It includes a preheating flue gas duct 1, a first variable diameter section 2, a working chamber 3, a second variable diameter section 5, and a postheating flue gas duct 6 connected in sequence. When the flue gas heat exchanger 4 located in the working chamber 3 is in working condition, the flue gas comes from the preheating flue gas duct 1, passes through the first variable diameter section 2, the flue gas heat exchanger 4, and the second variable diameter section 5 in sequence, and is then transported to the rear by the postheating flue gas duct 6.

[0028] Please refer to Figure 1 , Figure 2 , Figures 6 to 8 The low-temperature flue gas online heat extraction device includes a sealing assembly. When the flue gas heat exchanger 4 in the working chamber 3 is in operation, the sealing assembly seals the gap between the flue gas heat exchanger 4 and the inner wall of the working chamber 3 to prevent flue gas from leaking from the gap between the flue gas heat exchanger 4 and the inner wall of the working chamber 3.

[0029] Please refer to Figure 1 and Figure 2The low-temperature flue gas online heat extraction device includes a maintenance compartment 8, an electric gate valve 7, and a flue gas heat exchanger 4. The maintenance compartment 8 is installed on one side of the working compartment 3 and is connected to the working compartment 3. The electric gate valve 7 is installed at the connection between the working compartment 3 and the maintenance compartment 8. By controlling the gate of the electric gate valve 7 to open, the connection channel between the working compartment 3 and the maintenance compartment 8 is opened; by controlling the gate of the electric gate valve 7 to close, the inner cavities of the working compartment 3 and the maintenance compartment 8 are separated. The electric gate valve 7 has good sealing performance, improving the leakage risk of the shut-off valve. The flue gas heat exchanger 4 is movably installed, and can be located inside the working compartment 3 or the maintenance compartment 8. Figures 3 to 5 The diagrams show the positions of the flue gas heat exchanger 4 in the working compartment 3, from the working compartment 3 to the maintenance compartment 8, and in the maintenance compartment 8.

[0030] In detail, when the flue gas heat exchanger 4 needs inspection or maintenance, the electric gate valve 7 is opened, the sealing assembly is loosened, and the flue gas heat exchanger 4 is transferred to the maintenance chamber 8. After the inspection or maintenance is completed, it is returned to the working chamber 3. The low-temperature flue gas online heat extraction device disclosed in this embodiment eliminates the need for bypass flues and shut-off valves during maintenance and inspection, saving costs and space, and eliminating the risk of leakage associated with shut-off valves. During the inspection or maintenance process, the flue gas heat exchanger 4 is removed from the working chamber 3, that is, completely disconnected from the flue gas passage, thereby reducing the resistance of the flue gas system, reducing the fan energy consumption of the flue gas system, and also reducing the defects of ash accumulation and wear on the flue gas heat exchanger 4.

[0031] The low-temperature flue gas online heat extraction device disclosed in this embodiment transfers the flue gas heat exchanger 4 to the maintenance chamber 8 for inspection or maintenance. The maintenance chamber 8 is completely separated from the flue gas, has ample maintenance space, and provides a high level of safety. Furthermore, by setting up a first diameter-changing section 2 and a second diameter-changing section 5, the size compatibility requirements between the pipeline and the working chamber 3 are resolved. The sealing assembly prevents flue gas leakage, forming a unique flue gas path through the flue gas heat exchanger 4 in the working chamber 3.

[0032] Regarding the sealing assembly, in some implementations, please refer to... Figure 1 , Figure 2 , Figure 6 , Figure 7 and Figure 8The sealing assembly includes four single-leaf sealing valves 15 and a limiting block 17 installed outside the flue gas heat exchanger 4. The four single-leaf sealing valves 15 are respectively installed on the four sides of the working chamber 3. Specifically, the four sides are the four sides of the cross-section obtained by cutting the working chamber 3 with a section perpendicular to the airflow direction, including two vertical sides and two horizontal sides. Thus, two of the four single-leaf sealing valves 15 are arranged vertically and the other two are arranged horizontally. A flexible sealing strip 18 is installed on the limiting block 17. When the valve plate of the single-leaf sealing valve 15 abuts against the flexible sealing strip 18 on the limiting block 17, the sealing assembly seals the gap between the flue gas heat exchanger 4 and the inner wall of the working chamber 3.

[0033] It should also be noted that, in this embodiment, motion interference that exists during the opening and closing process of the four single-leaf sealing valves 15 is avoided. For details, please refer to... Figure 6 , Figure 7 and Figure 8 , Figure 6 The diagram shows the sealing of a vertically arranged single-leaf sealing valve 15. Figure 7 The diagram shows the sealing of a single-leaf sealing valve 15 arranged horizontally and located at a low position. Figure 8 This illustration shows the sealing of a horizontally arranged, high-positioned single-leaf sealing valve 15. It can be seen that the rotation of the single-leaf sealing valve 15 during the adjustment from a non-sealing to a sealing state is described based on its rotational position. Figure 6 The middle part is a counter-clockwise rotating, inward-pushing type. Figure 7 The middle is clockwise and inward-pushing. Figure 8 The middle part is clockwise and externally pressurized.

[0034] It should be noted that in this embodiment, the sealing assembly seals the gap between the flue gas heat exchanger 4 and the inner wall of the working chamber 3. This seal is a circumferential gap, but some small gaps are allowed, which is considered an incomplete seal.

[0035] Please refer to Figure 7 and Figure 8 When the two single-leaf sealing valves 15 along the horizontal plane are in a sealed state, the gravity of the valve leaf of the single-leaf sealing valve 15 is utilized to enhance the stability of the single-leaf sealing valve 15 in the sealed state.

[0036] In some implementation methods, please refer to Figures 1 to 5 The bottom of the working compartment 3 and the bottom of the maintenance compartment 8 are both provided with a track 9. The bottom of the flue gas heat exchanger 4 is equipped with casters 14, which are movably mounted on the track 9. The low-temperature flue gas online heat extraction device includes a drive mechanism that provides the power for the movement of the flue gas heat exchanger 4 and controls its movement, allowing the flue gas heat exchanger 4 to move on the track 9 under controlled conditions. The number of tracks 9 and casters 14 can be adjusted according to the specifications of the flue gas heat exchanger 4.

[0037] In some implementation methods, please refer to Figures 2 to 5 The electric gate valve 7 is connected to a gate valve actuator 10, which controls the movement of the valve plate of the electric gate valve 7, such as... Figures 3 to 5 As shown, the valve plate moves vertically.

[0038] In some embodiments, a limiting mechanism (not shown in the figure) is also installed on the track 9. The purpose of the limiting mechanism is to work with the flue gas heat exchanger 4 so that the flue gas heat exchanger 4 can move smoothly to the preset position in the working chamber 3 and stay fixed in the preset position, thereby improving the positioning accuracy of the flue gas heat exchanger 4 in the working chamber 3.

[0039] In some embodiments, the bottom of the valve plate of the electric gate valve 7 is provided with a groove, the groove being... Figure 2 As illustrated, there are two grooves formed at the lower edge of the valve plate. When the electric gate valve 7 cuts off the connection between the working chamber 3 and the maintenance chamber 8, the track 9 passes through the groove, thereby avoiding interference between the track 9 and the valve plate.

[0040] In some implementation methods, please refer to Figure 3 The maintenance compartment 8 is equipped with a movable maintenance door 11, which has an observation window 16. During the movement of the flue gas heat exchanger 4, the maintenance door 11 is closed to prevent significant flue gas leakage. Its operating status is observed through the observation window 16, including confirming whether it has moved into position. After it has moved into position, the maintenance door 11 must be opened only after the electric gate valve 7 has been closed.

[0041] In some implementation methods, please refer to Figures 3 to 5 A medium connection pipe 12 is installed on one side of the flue gas heat exchanger 4. A sleeve flange port 13 is installed on the side of the working chamber 3 away from the maintenance chamber 8. When the flue gas heat exchanger 4 is inside the working chamber 3, the medium connection pipe 12 passing through the sleeve flange port 13 is connected to the medium pipeline outside the working chamber 3. After being connected to the medium pipeline, the flue gas heat exchanger 4 is in working condition.

[0042] In some embodiments, the sleeve flange 13 is equipped with a blind flange, which seals the sleeve flange 13 when the flue gas heat exchanger 4 is removed from the working chamber 3, thereby preventing flue gas from leaking from the sleeve flange 13.

[0043] The opening and closing of the valve plate of the single-leaf sealing valve 15 mentioned above can be manually controlled, specifically by rotating a handwheel, or electrically controlled.

[0044] Example 2

[0045] Based on the low-temperature flue gas online heat extraction device provided in Embodiment 1, this embodiment discloses a low-temperature flue gas online heat extraction method, including:

[0046] The flue gas heat exchanger 4 is located inside the working chamber 3. The electric gate valve 7 is closed, and the single-leaf sealing valve 15 of the sealing assembly is adjusted so that the valve leaf of the single-leaf sealing valve 15 is aligned with the airflow direction. The flexible sealing strip 18 on the limit block 17 is pressed tightly. After adjustment, the opening of the valve leaf is fixed to seal the gap between the flue gas heat exchanger 4 and the inner wall of the working chamber 3.

[0047] Pass the medium pipe 12 through the sleeve flange 13, connect the medium pipe 12 to the medium conveying pipeline, and the flue gas heat exchanger 4 enters the working state to realize heat exchange with the flue gas.

[0048] When the flue gas heat exchanger 4 needs to be inspected or maintained, adjust the single-leaf sealing valve 15 to rotate its valve leaf at a certain angle so as not to obstruct the movement of the flue gas heat exchanger 4. This releases the seal of the sealing assembly on the gap between the flue gas heat exchanger 4 and the inner wall of the working chamber 3, and disconnects the connection between the medium pipe 12 and the medium conveying pipeline. Then, open the electric gate valve 7, and the flue gas heat exchanger 4 passes under the valve plate of the electric gate valve 7 and moves from the working chamber 3 to the designated position of the maintenance chamber 8 under the action of the drive mechanism.

[0049] After the flue gas heat exchanger 4 is moved to the maintenance compartment 8 and positioned, the electric gate valve 7 is closed. After the valve plate of the electric gate valve 7 is in place, the maintenance door 11 of the maintenance compartment 8 is opened to perform maintenance or repair operations on the flue gas heat exchanger 4.

[0050] After the flue gas heat exchanger 4 moves to the maintenance compartment 8, a blind flange is used to seal the sleeve flange 13 to prevent flue gas leakage.

[0051] During the movement of the flue gas heat exchanger 4, especially when the electric gate valve 7 is open, it is essential to ensure that the inspection door 11 is closed. The movement can be monitored through the observation window 16. After the heat exchanger is in place, ensure that the electric gate valve 7 is closed before opening the inspection door 11. Personnel may only enter after ventilation has been completed.

[0052] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0053] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A low-temperature flue gas on-line heat extraction device, characterized in that, The low-temperature flue gas online heat extraction device comprises: a pre-heat extraction flue gas pipeline, a first variable-diameter section, a working cabin, a second variable-diameter section and a post-heat extraction flue gas pipeline, which are sequentially connected; a maintenance cabin installed on one side of the working cabin and in communication with the working cabin; an electrically-driven gate valve installed at the connection between the working cabin and the maintenance cabin; a flue gas heat exchanger movably arranged in the working cabin or the maintenance cabin; a sealing assembly for sealing the gap between the flue gas heat exchanger and the inner wall of the working cabin when the flue gas heat exchanger is in the working cabin; wherein the sealing assembly comprises four single-leaf sealing valves and a limiting block, the four single-leaf sealing valves are respectively installed on the four sides of the cross section perpendicular to the airflow direction in the working cabin, two of the four single-leaf sealing valves are arranged vertically and the other two are arranged horizontally, the limiting block is installed on the flue gas heat exchanger, the limiting block is provided with a flexible sealing strip, and the sealing assembly seals the gap between the flue gas heat exchanger and the inner wall of the working cabin when the valve plate of the single-leaf sealing valve abuts against the flexible sealing strip on the limiting block; in the process of adjusting from non-sealing to sealing, the single-leaf sealing valves arranged vertically are limited to counter-clockwise rotation and internally push against the corresponding limiting blocks, the single-leaf sealing valves arranged horizontally and located at the lower part are limited to clockwise rotation and internally push against the corresponding limiting blocks, and the single-leaf sealing valves arranged horizontally and located at the higher part are limited to clockwise rotation and externally push against the corresponding limiting blocks.

2. The low temperature smoke online heat extraction device of claim 1, wherein, The bottom of the working cabin and the bottom of the maintenance cabin are jointly provided with a track, the bottom of the flue gas heat exchanger is provided with a moving wheel, and the moving wheel is movably installed on the track; the low-temperature flue gas online heat extraction device comprises a driving mechanism for controlling the movement of the flue gas heat exchanger on the track.

3. The low temperature flue gas on-line heat extraction device of claim 2, wherein, a limiting mechanism is installed on the track to facilitate the smooth movement of the flue gas heat exchanger to the preset position in the working cabin.

4. The low temperature flue gas on-line heat extraction device of claim 2, wherein, a groove is formed in the bottom of the valve plate of the electrically-driven gate valve, and the track is arranged in the groove when the electrically-driven gate valve cuts off the connection channel between the working cabin and the maintenance cabin.

5. The low temperature flue gas on-line heat extraction device of claim 1, wherein, the maintenance cabin is provided with a movable maintenance door, and the maintenance door is provided with an observation window.

6. The cryogenic flue gas on-line heat extraction device of claim 1, wherein, one side of the flue gas heat exchanger is provided with a medium connection pipe, and the working cabin is provided with a sleeve flange opening on the side away from the maintenance cabin, the medium connection pipe passes through the sleeve flange opening and is connected with the medium pipe network outside the working cabin when the flue gas heat exchanger is in the working cabin.

7. The low temperature flue gas on-line heat extraction device of claim 6, wherein, the sleeve flange opening is provided with a blind plate, and the blind plate seals the sleeve flange opening when the flue gas heat exchanger is removed from the working cabin.

8. The low temperature flue gas on-line heat extraction device of claim 7, wherein, the single-leaf sealing valves are configured to be electrically or manually controlled.

9. A method of on-line heat extraction from low-temperature flue gases, characterized by application of the low-temperature flue gas online heat extraction device according to any one of claims 1-8, the method comprises: the flue gas heat exchanger is in the working cabin, the electrically-driven gate valve is closed, the sealing assembly seals the gap between the flue gas heat exchanger and the inner wall of the working cabin, and the flue gas heat exchanger realizes heat exchange with flue gas; When the flue gas heat exchanger needs to be overhauled or maintained, the sealing assembly is disengaged from the gap between the flue gas heat exchanger and the inner wall of the working cabin, the electrically-driven gate valve is opened, and the flue gas heat exchanger is moved from the working cabin to the overhauling cabin; After the flue gas heat exchanger is moved to the overhauling cabin, the electrically-driven gate valve is closed, the overhauling cabin is opened, and the flue gas heat exchanger is overhauled or maintained.

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