Energy-saving electrolytic cell flue gas collection system

Abstract

This invention discloses an energy-saving electrolytic cell flue gas collection system, comprising main air ducts with different cross-sections and varying airflow designs, airflow regulating valves, pressure measuring ports, and differential pressure transmitters. The airflow regulating valves are installed in the exhaust duct of each exhaust hood. The pressure measuring ports are located at the air intake of each exhaust hood. Each pressure measuring port is connected to the differential pressure transmitter via a corresponding pressure measuring pipe. When the pressure difference of a certain exhaust hood exceeds the preset value of the differential pressure transmitter, the airflow regulating valve of that exhaust hood is adjusted accordingly to maintain a uniform negative pressure at all points within the exhaust hood. In this invention, pressure values ​​can be detected at each pressure measuring port, allowing for timely detection of excessively large gaps or improperly closed covers. An alarm can then prompt operators to make timely repairs. This ensures consistent negative pressure values ​​under each exhaust hood, thereby preventing the escape of harmful gases such as carbon dioxide and carbon tetrafluoride.

Description

Technical Field

[0001] This invention relates to energy-saving technology, specifically to an energy-saving electrolytic cell flue gas collection system. Background Technology

[0002] Electrolytic aluminum production is an energy-intensive industry. During production, the electrolyte operates at temperatures around 950℃-970℃. Harmful gases such as carbon dioxide and carbon tetrafluoride are generated during the production of elemental aluminum. To ensure a safe working environment, the exhaust system of the electrolytic cells collects these gases and directs them to a flue gas treatment system. To prevent these gases from escaping into the workshop, the exhaust system operates at a high negative pressure. While removing these gases, a large amount of air is also drawn away, resulting in exhaust temperatures not exceeding 200℃ and a significant loss of heat. This reduces the overall thermal efficiency of the electrolytic cells. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art, such as large exhaust volume, and to provide an energy-saving electrolytic cell flue gas collection system.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] An energy-saving electrolytic cell flue gas collection system includes main air ducts with different cross-sections designed for different air volumes, air volume regulating valves, pressure measuring ports, and differential pressure transmitters; wherein...

[0006] The main air ducts with different cross-sections designed for different air volumes are located at the top of the smoke exhaust system. The pipe diameter is different according to the different smoke volume at different locations of the duct, so as to ensure that the pressure at each smoke exhaust point is basically equal.

[0007] The air volume regulating valve is installed in the flue gas collection channel of each exhaust hood and is driven by compressed air;

[0008] The pressure measuring port is set at the air intake of each smoke hood; each pressure measuring port is connected to the differential pressure transmitter through a corresponding pressure measuring pipe; when the pressure difference of a certain smoke hood exceeds the value preset by the differential pressure transmitter, the air volume regulating valve of the smoke hood is adjusted accordingly to keep the negative pressure at all points in the smoke hood the same.

[0009] Furthermore, the energy-saving electrolytic cell flue gas collection system also includes an alarm. When the pressure difference of a certain exhaust hood exceeds the value preset by the differential pressure transmitter, the alarm will sound an alarm.

[0010] Furthermore, the exhaust hood includes a cover plate, which is installed on the upper edge of the electrolytic cell. The upper edge of the electrolytic cell is installed on the electrolytic cell support. An adjusting bolt is provided on the upper edge of the electrolytic cell support. The installation position of the upper edge of the electrolytic cell on the electrolytic cell support is adjusted by adjusting the bolt, thereby adjusting the flatness of the upper edge of the electrolytic cell.

[0011] Furthermore, the adjusting bolt includes a screw, an upper locking nut, and a lower locking nut, and the upper edge of the electrolytic cell is installed in the screw and located between the upper locking nut and the lower locking nut; a soft connection layer is provided on the upper surface of the upper edge of the electrolytic cell.

[0012] Furthermore, the width of the cover plate is based on the premise that the weight of the cover plate does not increase. Due to the addition of the insulation layer, the cover plate is slightly narrower than the currently used cover plate with a width of 730 mm, which makes it easier for workers to operate.

[0013] Furthermore, the cover plate has different areas where temperature and pressure displays are arranged on the cover plate to display the pressure and temperature inside the fume hood in real time.

[0014] Furthermore, different cover plate fixing points are marked with colors or serial numbers.

[0015] Furthermore, the upper and lower edges of the cover plate are flexibly connected; a hinge spring is provided on the upper edge of the cover plate to ensure that one side can always be in close contact with the upper edge of the electrolytic cell.

[0016] Furthermore, when the temperature on the main duct exceeds the set range, the alarm will sound; the main duct refers to the pipe from the various exhaust hoods of the electrolytic cell to the flue gas treatment system.

[0017] Furthermore, a pressure measuring point switch valve is installed in the pressure measuring pipeline connected to each pressure measuring port and the differential pressure transmitter.

[0018] Compared with the prior art, the advantages of this invention are as follows:

[0019] In this invention, pressure values ​​can be detected at each pressure measuring port, allowing for timely detection of excessively large gaps or improperly closed covers. An alarm can then alert operators to make timely repairs. This ensures consistent negative pressure values ​​under each exhaust hood, preventing the escape of harmful gases such as carbon dioxide and carbon tetrafluoride. Furthermore, by setting pressure measuring points at different exhaust ports, problems can be detected promptly, or pressure balance can be achieved by adjusting the airflow valve, thus avoiding the need to reduce pressure on the main pipe to achieve excessively low local negative pressure. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the pressure measurement point distribution of the energy-saving electrolytic cell flue gas collection system provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the cover plate frame sealing mechanism;

[0022] Figure 3 This is a schematic diagram of the sealing mechanism along the upper edge of the electrolytic cell;

[0023] Figure 4 A schematic diagram of a cover plate spring hinge mechanism;

[0024] In the diagram: 1. Air volume regulating valve; 2. Pressure measuring port; 3. Differential pressure transmitter; 4. Smoke hood; 5. Main air duct; 6. Pressure measuring point switch valve; 7. Cover plate; 8. Upper edge of electrolytic cell; 9. Screw; 10. Upper locking nut; 11. Lower locking nut; 12. Flexible connection layer; 13. Hinge spring; 14. Handle; 15. Sealing head; 16. Guide rod; 17. Spring; 18. Guide rail; 19. Electrolytic cell support. Detailed Implementation

[0025] Example:

[0026] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] See Figure 1 As shown, the energy-saving electrolytic cell flue gas collection system provided in this embodiment mainly includes a main air duct 5 with different cross-sections designed according to different air volumes, an air volume regulating valve 1, a pressure measuring port 2, and a differential pressure transmitter 3.

[0028] The main ducts 5, with different cross-sections and varying airflow designs, are located at the top of the smoke exhaust system. The duct diameter varies depending on the location of the smoke volume, ensuring that the pressure at each exhaust point is essentially equal. An airflow regulating valve 1 is installed in the exhaust channel of each smoke hood 4. A pressure measuring port 2 is located at the air intake of each smoke hood 4. Each pressure measuring port 2 is connected to a differential pressure transmitter 3 via a corresponding pressure measuring pipe. When the pressure difference of a smoke hood 4 exceeds the preset value of the differential pressure transmitter 3, the airflow regulating valve of that smoke hood is adjusted accordingly to maintain the same negative pressure at all points within the smoke hood 4, ensuring that the total negative pressure of the system is achieved and not lowered. Within the smoke hood 4, the escape of harmful gases such as carbon dioxide and carbon tetrafluoride occurs when the pressure is higher than the ambient air pressure. Due to the long length of the electrolytic cell, the cover plates 7 of traditional flue gas emission systems are placed piece by piece. If some cover plates are deformed or not properly placed, gaps will appear. To maintain the negative pressure value at this point, the suction volume needs to be increased, thereby increasing the system's smoke exhaust volume. For long electrolytic cells, to ensure that harmful gases do not escape from any gaps and that the pressure at any gaps remains negative, the exhaust volume of the main duct must be increased. In this invention, pressure values ​​can be detected at each pressure measuring port. If the pressure value at a measuring port changes excessively, an alarm will alert the operator to promptly identify an excessively large gap or an improperly closed cover, ensuring timely repair. This maintains consistent negative pressure values ​​under each exhaust hood, preventing the escape of harmful gases such as carbon dioxide and carbon tetrafluoride, while also preventing the removal of large amounts of workshop air, reducing flue gas emissions, and avoiding the loss of significant heat. This invention patent, by setting pressure measuring points at different exhaust ports, allows for timely detection of problems or pressure balancing by adjusting the airflow valve, thus avoiding the need to reduce the pressure on the main duct to achieve excessively low local negative pressure. Furthermore, the alarm will also sound when the temperature on the main duct 5 exceeds the set range.

[0029] As a preferred embodiment of this energy-saving electrolytic cell flue gas collection system, a pressure measuring point switch valve 6 is installed in the pressure measuring pipeline connected to each pressure measuring port and the differential pressure transmitter. Since there may be some dust in the flue gas, the pressure measuring point switch valve 6 is normally in the closed state. When it is necessary to know the pressure at this point, the pressure measuring point switch valve 6 is opened, which ensures the accuracy of the measured pressure.

[0030] Furthermore, the exhaust hood 4 includes a cover plate 7, the upper edge of which is mounted on the upper edge 8 of the electrolytic cell, which is in turn mounted on the electrolytic cell support 19. During production, ensuring a good seal between the cover plate 7 and the upper edge 8 of the electrolytic cell requires maintaining a certain degree of flatness on the upper edge 8, which is a prerequisite for a good seal between the different cover plates 7. During normal production, when changing the anode, the electrolytic cell support 19 is inevitably touched, causing changes in the flatness of the upper edge 8 and affecting the sealing effect of the cover plate 7. Therefore, this patent provides an adjusting bolt on the upper edge of the electrolytic cell support 19. Adjusting the bolt allows for adjustment of the installation position of the upper edge 8 on the electrolytic cell support 19, ensuring the flatness of the upper edge 7 to a certain extent, thus guaranteeing the sealing effect of the cover plate 7. Additionally, a flexible connecting layer is provided on the upper edge, which also contributes to ensuring a good seal.

[0031] like Figure 3 As shown, during the manufacturing and installation process, the electrolytic cell support 19 may not be on the same horizontal plane. Therefore, gaps may appear when placing the cover plate 7. This invention addresses this by adding an adjusting bolt to the original electrolytic cell support 19. This adjusting bolt includes a screw 9, an upper locking nut 10, and a lower locking nut 11. The upper edge 8 of the electrolytic cell is installed in the screw 9 and located between the upper locking nut 10 and the lower locking nut 11. Thus, by adjusting the upper locking nut 10 and the lower locking nut 11, the upper part of the electrolytic cell exhaust hood cover plate 7 can be ensured to be on the same horizontal plane. If slight deformation occurs during operation due to minor collisions, the upper part of the exhaust hood cover plate 7 can be adjusted to be on the same horizontal plane using the upper locking nut 10 and the lower locking nut 11. A flexible connecting layer 12 is provided on the upper surface of the upper edge 8 of the electrolytic cell to ensure a good seal with the cover plate 7.

[0032] Because anodes in the workshop constantly need to be replaced, the labor intensity for operators is high. If cover plate 7 is too heavy, it will affect the operation of replacing the cover plate. Compared with the existing cover plate, the weight should not be greater than that of the existing cover plate 7. Since the existing cover plate has added sealing accessories and insulation layer, in order to ensure that the weight of the cover plate remains unchanged or is reduced, the width of the cover plate needs to be appropriately reduced. Therefore, in this application, the reduction of the cover plate width should be based on the premise that the weight of the cover plate does not increase. Due to the addition of the insulation layer, the cover plate is slightly narrower than the currently used cover plate with a width of 730 mm, which is convenient for workers to operate. At the same time, the cover plate frame is made of lightweight and high-strength aluminum alloy, and a crossbeam is set on the upper surface of the cover plate to facilitate workers' operation.

[0033] In addition, the upper and lower edges of the cover plate 7 are sealed, and the upper and lower edges of the cover plate are flexibly connected to ensure a sealing effect. Meanwhile, as... Figure 4As shown, a hinged spring 13 is provided on the upper edge of the cover plate to ensure that one side can always be in close contact with the upper edge 8 of the electrolytic cell. The elastic control provides compensation for the flexible connection and ensures the sealing performance. The system is easy to remove and put in. A handle 14 is provided on the cover plate 7 to make it easy to remove or put in the cover plate, ensuring convenient operation.

[0034] In addition, different cover plates are marked with colors or serial numbers at their seven fixed points to ensure that the cover plates are not placed incorrectly and to ensure the sealing effect; temperature and pressure displays are arranged on the cover plates to know the pressure and temperature distribution of the cover plates in real time.

[0035] Optionally, sealing fittings are provided on the left and right sides of the aforementioned cover plate, such as... Figure 2 As shown, the sealing fitting consists of four parts: first, a sealing head 15 with a groove at the top; second, a sealing head 15 fixed in the middle by a guide rod 16 and a spring 17, which can move back and forth along a guide rail 18; third, the guide rail 18 allows the sealing head 15 to move back and forth; fourth, the guide rod 16 is used to fix the spring 17 and the sealing head 15; and fifth, the spring 17 ensures that the sealing head 15 maintains a good seal. A high-temperature resistant soft sealing material is arranged in the groove of the sealing head 15, which can withstand temperatures above 150°C. This part of the seal is... Figure 1 The seal is applied to a portion of the frame. This semi-circular retractable block moves back and forth. The outer edge of the retractable part is in a guide groove, ensuring that the retractable part moves within a certain range. The retractable range is approximately 10mm, and the soft sealing material can be compressed by about 2mm. Therefore, the sealing adjustment range for each frame is 12mm on one side, with a maximum adjustment range of 24mm on both sides. The retractable parts of adjacent cover plates are connected with convex and concave joints, forming a labyrinthine sealing effect locally, such as... Figure 2 As shown, after the two cover plates are placed, the springs 17 of the sealing head 15 will be appropriately compressed, resulting in a soft seal at the front end. Because the sealing head is arc-shaped, it facilitates easy movement or placement of the cover plates. Simultaneously, the cover plates can be easily removed or assembled, and the sealing effect is controlled internally by a spring system. A 10mm layer of ceramic fiber cotton is added to the middle of the cover plates, compressed to 5mm, and then fixed to enhance the insulation effect.

[0036] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An energy-saving electrolytic cell flue gas collection system, characterized in that, This includes main air ducts with different cross-sections designed for different air volumes, air volume regulating valves, pressure measuring ports, and differential pressure transmitters; among which, The main air ducts with different cross-sections designed for different air volumes are located at the top of the smoke exhaust system. The pipe diameter is different according to the different smoke volume at different locations of the duct, so as to ensure that the pressure at each smoke exhaust point is basically equal. The air volume regulating valve is installed in the flue gas collection channel of each exhaust hood and is driven by compressed air; The pressure measuring port is set at the air intake of each smoke hood; each pressure measuring port is connected to the differential pressure transmitter through a corresponding pressure measuring pipe; when the pressure difference of a certain smoke hood exceeds the value preset by the differential pressure transmitter, the air volume regulating valve of the smoke hood is adjusted accordingly to keep the negative pressure at all points in the smoke hood the same. It also includes an alarm. When the pressure difference between a certain exhaust hood and the set value exceeds the value preset by the differential pressure transmitter, the alarm will sound to remind the operator to perform maintenance. The exhaust hood includes a cover plate, the upper edge of which rests on the upper edge of the electrolytic cell. The upper edge of the electrolytic cell is mounted on an electrolytic cell support. An adjusting bolt is provided on the upper edge of the electrolytic cell support. The installation position of the upper edge of the electrolytic cell on the electrolytic cell support is adjusted by adjusting the bolt, thereby adjusting the flatness of the upper edge of the electrolytic cell. Sealing accessories are provided on both sides of the cover plate. Each sealing accessory consists of four parts: first, a sealing head with a groove at the top, which is fixed in the middle by a guide rod and a spring and moves back and forth along the guide rail; second, the guide rail part, which allows the sealing head to move back and forth; and third, the guide rod, which is used to fix the spring and the sealing head. The spring ensures that the sealing head always maintains good sealing performance. High-temperature resistant soft sealing material is arranged in the groove of the sealing head. The high-temperature resistant soft sealing material can withstand temperatures above 150°C. The retractable parts of adjacent cover plates are connected by convex and concave joints, forming a labyrinthine sealing effect in some areas.

2. The energy-saving electrolytic cell flue gas collection system as described in claim 1, characterized in that, The adjusting bolt includes a screw, an upper locking nut, and a lower locking nut. The upper edge of the electrolytic cell is installed in the screw and located between the upper locking nut and the lower locking nut. A soft connection layer is provided on the upper surface of the upper edge of the electrolytic cell.

3. The energy-saving electrolytic cell flue gas collection system as described in claim 1 or 2, characterized in that, The width of the cover plate is designed so as not to increase the weight of the cover plate. The cover plate is provided with an insulation layer and the width of the cover plate is less than 730 mm.

4. The energy-saving electrolytic cell flue gas collection system as described in claim 1, characterized in that, Some of the display covers are equipped with temperature and pressure displays to show the pressure and temperature inside the fume hood in real time.

5. The energy-saving electrolytic cell flue gas collection system as described in claim 1, characterized in that, Different cover plate fixing points are marked with colors or serial numbers.

6. The energy-saving electrolytic cell flue gas collection system as described in claim 1, characterized in that, The upper and lower edges of the cover plate are flexibly connected; a hinge spring is provided on the upper edge of the cover plate to ensure that one side can always be in close contact with the upper edge of the electrolytic cell.

7. The energy-saving electrolytic cell flue gas collection system as described in claim 1, characterized in that, When the temperature on the main air duct exceeds the set range, the alarm will sound.

8. The energy-saving electrolytic cell flue gas collection system as described in claim 1, characterized in that, A pressure measuring point switch valve is installed in the pressure measuring pipeline connected to each pressure measuring port and the differential pressure transmitter.

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