Anti-blocking device for methanol to olefins

Abstract

This utility model discloses an anti-clogging device for methanol-to-olefins (MTO) systems, relating to the field of water washing anti-clogging devices. It includes a water washing tower, a water washing pump, and a C5 refueling assembly. The C5 refueling assembly comprises, in sequence, a C5 self-separation unit pipeline, a fuel oil / C5 flow meter, a fuel oil tank inlet pipeline regulating valve, a C5 inlet pipeline, a fuel oil pump, a fuel oil pump outlet pressure control valve, and a C5 to water washing pump inlet pipeline, thus forming a continuous refueling path. This utility model, by setting up the C5 refueling assembly and injecting C5, a byproduct of the C5 self-separation unit, utilizes the principle of "like dissolves like" to alter the surface tension of the medium, forming an oil-water two-phase flow that reduces the deposition rate of solid particles. The C5 thus dissolves and removes scale buildup in the system. By utilizing the chemical dissolving effect of C5, the clogging problem in the water washing system of a MTO unit is effectively prevented.

Description

Technical Field

[0001] This utility model relates to the technical field of water washing anti-clogging devices, and in particular to an anti-clogging device for methanol-to-olefins. Background Technology

[0002] In a methanol-to-olefins (MTO) unit, the feedstock methanol reacts in a fluidized bed reactor. The product gas, after being decomposed by a multi-stage cyclone separator to remove catalyst particles, is sent to a quench tower for washing and cooling. Due to limitations in the separation precision of the upstream cyclone separator, most catalyst particles enter the quench water, while a small amount of fine catalyst particles enter the water washing tower with the reactor. Simultaneously, the heavy components in the methanol feedstock and the MTO reaction produce some aromatic byproducts (mainly polymethylbenzene). Because the quench water system operates at a relatively high temperature (109°C), most of these byproducts have high melting and boiling points and do not solidify in the quench water system. Therefore, they enter the water washing tower with the product gas for washing and cooling. However, the temperature inside the water washing tower is low, causing the polymethylbenzene to condense and form oily wax in the washing water system. Therefore, the washing water is characterized by containing a small amount of fine catalyst particles and oily waxy substances.

[0003] However, the oily and waxy organic matter in the water washing system, along with the entrained fine catalyst particles, can easily cause blockage in the water washing tower, leading to tower overflow accidents and posing a challenge to the safe and stable operation of the equipment. In view of this, this application proposes an anti-blocking device for methanol-to-olefins based on the above-mentioned technical problems. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing an anti-clogging device for methanol-to-olefins.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An anti-clogging device for methanol-to-olefins includes a water washing tower, a water washing pump, and a C5 filling assembly. The C5 filling assembly includes a C5 self-separation unit pipeline, a fuel oil / C5 flow meter, a fuel oil tank inlet pipeline regulating valve, a C5 to inlet pipeline, a fuel oil pump, a fuel oil pump outlet pressure control valve, and a C5 to water washing pump inlet pipeline, which are connected in sequence to form a continuous filling passage. The washing tower is equipped with a rotary wax scraping assembly, which includes a filter cylinder and an inclined scraper that contacts the inner wall of the filter cylinder. The top of the washing tower is connected to a water inlet pipe, the bottom of the washing tower is connected to a water outlet pipe, the bottom of the washing tower is provided with a bottom cover, and a cover opening assembly is provided between the bottom cover and the washing tower. The top of the washing tower is fixedly installed with a top cover by bolts.

[0007] Furthermore, the rotary scraper assembly also includes a motor fixedly mounted on the upper surface of the top cover. A rotating rod is fixedly mounted on the output end of the motor. Several bushings are fixedly mounted on the rotating rod. A sleeve is fixedly mounted on one side of the bushing. A sliding rod is slidably mounted inside the sleeve. A spring is fixedly mounted between the sliding rod and the sleeve. The inclined scraper is fixedly mounted on the sliding rod.

[0008] Furthermore, the inclined scrapers are distributed in a spiral pattern along the axis of the rotating rod.

[0009] Furthermore, the inner wall of the sleeve is provided with a sliding groove, and a slider is slidably installed in the sliding groove, the slider being fixedly connected to the sliding rod.

[0010] Furthermore, a number of fixed blocks arranged in a ring array are fixedly installed inside the water washing tower near the bottom. Fixed rings are fixedly installed between the fixed blocks, and a fixed groove matching the filter cartridge is provided above the fixed ring.

[0011] Furthermore, the lowest point of the water outlet pipe is higher than the lowest point of the filter cartridge.

[0012] Furthermore, the opening assembly includes a connecting seat fixedly installed on the outer wall of the water washing tower. The connecting seat includes an upper seat and a lower seat with an included angle of 90 degrees. A first opening is provided on one side of the upper seat, and a cylinder is rotatably installed at the first opening via a rotating shaft. A second opening is provided on one side of the lower seat, and a connecting plate is rotatably installed at the second opening via a rotating shaft. A U-shaped plate is fixedly installed on one side of the connecting plate. The included angle between the connecting plate and the U-shaped plate is an obtuse angle. The output end of the cylinder is rotatably connected to the U-shaped plate.

[0013] Furthermore, a sealing strip is fixedly installed on the bottom cover, and the sealing strip is in contact with the inner wall of the water washing tower.

[0014] The beneficial effects of this utility model are as follows: 1. This utility model incorporates a C5 filling assembly, an inclined scraper, and a filter cartridge. The C5 in the C5 self-separation unit pipeline is connected to the C5 inlet pipeline via a fuel oil / C5 flow meter and a fuel oil tank inlet pipeline regulating valve. After being pressurized by the fuel oil pump, it is then sent to the inlet of the water washing pump via the fuel oil pump outlet pressure control valve. By adding C5, a byproduct of the C5 self-separation unit, based on the principle of "like dissolves like," the non-polar C5 alters the surface tension of the medium, forming an oil-water two-phase flow that reduces the deposition rate of solid particles. The C5 dissolves and peels away scale buildup in the system. Utilizing the chemical dissolving effect of C5, the clogging problem in the water washing system in the methanol-to-olefins unit is effectively prevented. Incompletely dissolved oil and wax scale flows into the water washing tower, where the filter cartridge separates solid particles from the liquid, further purifying the water flow. The rotating inclined scraper removes the deposits on the filter cartridge, preventing clogging.

[0015] 2. This utility model, by setting up a rotary wax scraping assembly, allows for the further removal of residual oil and wax scale in the water washing tower. Liquid enters the water washing tower through the inlet pipe, while solid particles are blocked by the filter cartridge in the channel between the filter cartridge and the water washing tower and settle at the bottom of the water washing tower. Meanwhile, the washing water flows out through the outlet pipe, achieving solid-liquid separation. Simultaneously, the motor is started, driving the rotating rod to rotate. The rotating rod also drives multiple inclined scrapers to rotate. The inclined scrapers move in a spiral path, scraping the inner wall of the filter cartridge, effectively removing stubborn oil and wax scale adhering to the filter cartridge, preventing filter cartridge blockage, and improving solid-liquid separation efficiency. In addition, the spiral movement path design of the inclined scrapers ensures that they can evenly cover the inner wall of the filter cartridge during scraping, ensuring thorough cleaning. This design not only solves the blockage problem of the water washing system but also improves the operating efficiency and stability of the equipment.

[0016] 3. This utility model, by setting up a cover opening component, after the equipment has been running for a period of time, stops the water inlet pipe, drains the water in the water washing tower through the outlet pipe, starts the cylinder, retracts the cylinder output end, and drives the U-shaped plate and connecting plate to rotate, ultimately causing the bottom cover to flip over, so that excess oil and wax scale can be removed from the water washing tower, thus achieving centralized treatment of oil and wax scale.

[0017] 4. This utility model, by setting up a sliding rod, sleeve, and spring, ensures that the inclined scraper does not interfere with the inner wall of the filter cartridge during rotation. When the inclined scraper rotates and contacts the inner wall of the filter cartridge, the sliding rod is pressured and moves into the sleeve, and the spring is compressed. In order to further ensure that the angle of the inclined scraper does not deflect, the sliding rod is restricted by the sliding groove during movement, thereby ensuring that the inclined scraper maintains a stable angle during scraping. This effectively removes oil and wax deposits on the filter cartridge without damaging the inner wall of the filter cartridge. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a process for an anti-clogging device for methanol-to-olefins proposed in this utility model. Figure 2 This is a schematic diagram of a water washing tower for an anti-clogging device in methanol-to-olefins proposed in this utility model. Figure 3 This is a cross-sectional schematic diagram of a water washing tower for an anti-clogging device in methanol-to-olefins proposed in this utility model. Figure 4 This is a schematic diagram of a rotary wax scraper assembly for an anti-clogging device in methanol-to-olefins proposed in this utility model. Figure 5 This is a cross-sectional schematic diagram of a filter cartridge for an anti-clogging device for methanol-to-olefins proposed in this utility model. Figure 6This is a cross-sectional schematic diagram of the sleeve of an anti-clogging device for methanol-to-olefins proposed in this utility model; Figure 7 This is a schematic diagram of the opening assembly of an anti-clogging device for methanol-to-olefins proposed in this utility model. Figure 8 This is a schematic diagram of a connection seat for an anti-clogging device for methanol-to-olefins proposed in this utility model; Figure 9 This is a schematic diagram of the bottom cover flipping of an anti-clogging device for methanol-to-olefins proposed in this utility model.

[0019] In the diagram: 1. C5 self-separation unit pipeline; 2. Fuel oil / C5 flow meter; 3. Fuel oil tank inlet pipeline regulating valve; 4. C5 to inlet pipeline; 5. Fuel oil pump; 6. Fuel oil pump outlet pressure control valve; 7. C5 to water washing pump inlet pipeline; 8. Water washing pump; 9. Water washing tower; 10. Filter cartridge; 11. Inclined scraper; 12. Water inlet pipe; 13. Water outlet pipe; 14. Bottom cover; 15. Top cover; 16. Motor; 17. Rotating rod; 18. Bushing; 19. Sleeve; 20. Sliding rod; 21. Spring; 22. Slide groove; 23. Sliding block; 24. Fixing block; 25. Fixing ring; 26. Fixing groove; 27. Connecting seat; 28. Upper seat; 29. ​​Lower seat; 30. First opening; 31. Cylinder; 32. Second opening; 33. Connecting plate; 34. U-shaped plate; 35. Sealing strip. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0021] Reference Figure 1-4 An anti-clogging device for methanol-to-olefins includes a water washing tower 9, a water washing pump 8, and a C5 filling assembly. The C5 filling assembly includes a C5 self-separation unit pipeline 1, a fuel oil / C5 flow meter 2, a fuel oil tank inlet pipeline regulating valve 3, a C5 to inlet pipeline 4, a fuel oil pump 5, a fuel oil pump outlet pressure control valve 6, and a C5 to water washing pump inlet pipeline 7, which are connected in sequence to form a continuous filling passage. The washing tower 9 is equipped with a rotary wax scraping assembly inside. The rotary wax scraping assembly includes a filter cylinder 10 disposed inside the washing tower 9 and an inclined scraper 11 that contacts the inner wall of the filter cylinder 10. The top of the washing tower 9 is connected to a water inlet pipe 12, the bottom of the washing tower 9 is connected to a water outlet pipe 13, the bottom of the washing tower 9 is provided with a bottom cover 14, and a cover opening assembly is provided between the bottom cover 14 and the washing tower 9. The top of the washing tower 9 is fixedly installed with a top cover 15 by bolts. The C5 in the C5 self-separation unit pipeline 1 is connected to the C5 inlet pipeline 4 via the fuel oil / C5 flow meter 2 and the fuel oil tank inlet pipeline regulating valve 3. After being pressurized by the fuel oil pump 5, it is sent to the inlet of the water washing pump 8 via the fuel oil pump outlet pressure control valve 6. By adding the self-produced by-product C5 of the C5 self-separation unit, based on the principle of like dissolves like, the non-polar C5 changes the surface tension of the medium, forming an oil-water two-phase flow and reducing the deposition rate of solid particles. The C5 thus dissolves and peels off the scale in the system. The chemical dissolving effect of C5 effectively prevents the clogging problem of the water washing system in the methanol-to-olefins unit. The incompletely dissolved oil and wax scale flows into the water washing tower 9, where the filter cartridge 10 is used to separate solid particles from liquid, further purifying the water flow. The rotating inclined scraper 11 can scrape off the deposits on the filter cartridge 10 to prevent clogging.

[0022] Reference Figure 1 , Figure 4 , Figure 6 Specifically: the rotary scraper assembly also includes a motor 16 fixedly installed on the upper surface of the top cover 15. A rotating rod 17 is fixedly installed at the output end of the motor 16. Several bushings 18 are fixedly installed on the rotating rod 17. A sleeve 19 is fixedly installed on one side of the bushing 18. A sliding rod 20 is slidably installed inside the sleeve 19. A spring 21 is fixedly installed between the sliding rod 20 and the sleeve 19. The inclined scraper 11 is fixedly installed on the sliding rod 20.

[0023] Reference Figure 3-4 Specifically: the inclined scraper 11 is distributed in a spiral along the axis of the rotating rod 17; When further removal of remaining oil and wax scale inside the water washing tower 9 is required, liquid is introduced into the water washing tower 9 through the inlet pipe 12. Solid particles are blocked by the filter cartridge 10 in the channel between the filter cartridge 10 and the water washing tower 9 and settle at the bottom of the water washing tower 9, while the washing water flows out from the outlet pipe 13, achieving the effect of solid-liquid separation. At the same time, the motor 16 is started, and the motor 16 drives the rotating rod 17 to rotate. The rotating rod 17 drives multiple inclined scrapers 11 to rotate. The inclined scrapers 11 move in a spiral path and scrape the inner wall of the filter cartridge 10, effectively removing the stubborn oil and wax scale attached to the filter cartridge 10, avoiding the filter cartridge 10 from clogging, and improving the solid-liquid separation efficiency. In addition, the spiral movement path design of the inclined scrapers 11 allows them to evenly cover the inner wall of the filter cartridge 10 during the scraping process, ensuring that there are no dead corners in the cleaning. Through this setting, not only is the clogging problem of the water washing system solved, but the operating efficiency and stability of the equipment are also improved.

[0024] Reference Figure 6Specifically: the inner wall of the sleeve 19 is provided with a groove 22, and a slider 23 is slidably installed in the groove 22. The slider 23 is fixedly connected to the slider rod 20. In order to ensure that the inclined scraper 11 does not interfere with the inner wall of the filter cartridge 10 during rotation, when the inclined scraper 11 rotates and contacts the inner wall of the filter cartridge 10, the slider rod 20 is pressured and moves into the sleeve 19, and the spring 21 is compressed. In order to further ensure that the angle of the inclined scraper 11 does not deflect, the slider rod 20 is restricted by the groove 22 during movement, thereby ensuring that the inclined scraper 11 maintains a stable angle during scraping, which can effectively remove oil and wax scale on the filter cartridge 10 without damaging the inner wall of the filter cartridge 10.

[0025] Reference Figure 3 , Figure 5 Specifically: Several fixing blocks 24 arranged in a ring array are fixedly installed inside the water washing tower 9 near the bottom. Fixing rings 25 are fixedly installed between the fixing blocks 24. A fixing groove 26 matching the filter cartridge 10 is provided above the fixing ring 25. When the filter cartridge 10 is installed inside the water washing tower 9, it can be inserted into the fixing groove 26 to complete the quick installation.

[0026] Reference Figure 3 Specifically, the lowest point of the water outlet pipe 13 is higher than the lowest point of the filter cartridge 10.

[0027] Reference Figure 3 , Figure 8-9 Specifically: the opening assembly includes a connecting seat 27 fixedly installed on the outer wall of the washing tower 9. The connecting seat 27 includes an upper seat 28 and a lower seat 29 with an included angle of 90 degrees. A first opening 30 is provided on one side of the upper seat 28. A cylinder 31 is rotatably installed at the first opening 30 via a rotating shaft. A second opening 32 is provided on one side of the lower seat 29. A connecting plate 33 is rotatably installed at the second opening 32 via a rotating shaft. A U-shaped plate 34 is fixedly installed on one side of the connecting plate 33. The included angle between the connecting plate 33 and the U-shaped plate 34 is an obtuse angle. The output end of the cylinder 31 is rotatably connected to the U-shaped plate 34. After the equipment has been running for a period of time, the water inlet pipe 12 is stopped, the water outlet pipe 13 drains the water in the water washing tower 9, the cylinder 31 is started, the output end of the cylinder 31 is retracted, the cylinder 31 drives the U-shaped plate 34 and the connecting plate 33 to rotate, and finally drives the bottom cover 14 to flip over, so that the excess oil and wax scale is removed from the water washing tower 9, realizing the centralized treatment of oil and wax scale.

[0028] Reference Figure 7 Specifically: a sealing strip 35 is fixedly installed on the bottom cover 14, and the sealing strip 35 is in contact with the inner wall of the water washing tower 9.

[0029] Working principle: The C5 in the C5 self-separation unit pipeline 1 is connected to the C5 inlet pipeline 4 via the fuel oil / C5 flow meter 2 and the fuel oil tank inlet pipeline regulating valve 3. After being pressurized by the fuel oil pump 5, it is sent to the inlet of the water washing pump 8 through the fuel oil pump outlet pressure control valve 6. By adding the self-produced by-product C5 of the C5 self-separation unit, according to the principle of like dissolves like, the non-polar C5 changes the surface tension of the medium, forming an oil-water two-phase flow and reducing the deposition rate of solid particles. The C5 thus dissolves and peels off the scale in the system. The chemical dissolving effect of C5 effectively prevents the clogging problem of the water washing system in the methanol-to-olefins unit. The incompletely dissolved oil and wax scale flows into the water washing tower 9, where the filter cartridge 10 is used to separate solid particles from liquid, further purifying the water flow. The rotating inclined scraper 11 can scrape off the deposits on the filter cartridge 10 to prevent clogging. When further removal of remaining oil and wax scale in the water washing tower 9 is required, liquid is introduced into the water washing tower 9 through the inlet pipe 12. Solid particles are blocked by the filter cartridge 10 in the channel between the filter cartridge 10 and the water washing tower 9 and settle at the bottom of the water washing tower 9, while the washing water flows out from the outlet pipe 13, achieving the effect of solid-liquid separation. At the same time, the motor 16 is started, and the motor 16 drives the rotating rod 17 to rotate. The rotating rod 17 drives multiple inclined scrapers 11 to rotate. The inclined scrapers 11 move in a spiral path and scrape the inner wall of the filter cartridge 10, effectively removing the stubborn oil and wax scale attached to the filter cartridge 10, avoiding the filter cartridge 10 from clogging, and improving the solid-liquid separation efficiency. In addition, the spiral movement path design of the inclined scrapers 11 allows them to evenly cover the inner wall of the filter cartridge 10 during the scraping process, ensuring that there are no dead corners in the cleaning. Through this setting, not only is the clogging problem of the water washing system solved, but the operating efficiency and stability of the equipment are also improved. After the equipment has been running for a period of time, the water inlet pipe 12 is stopped, the water outlet pipe 13 drains the water in the water washing tower 9, the cylinder 31 is started, the output end of the cylinder 31 is retracted, the cylinder 31 drives the U-shaped plate 34 and the connecting plate 33 to rotate, and finally drives the bottom cover 14 to flip over, so that the excess oil and wax scale can be removed from the water washing tower 9, and the oil and wax scale can be centrally treated. To ensure that the inclined scraper 11 does not interfere with the inner wall of the filter cartridge 10 during rotation, when the inclined scraper 11 rotates and contacts the inner wall of the filter cartridge 10, the slide rod 20 is pressured and moves into the sleeve 19, and the spring 21 is compressed. In order to further ensure that the angle of the inclined scraper 11 does not deflect, the slide rod 20 is restricted by the slide groove 22 during movement, thereby ensuring that the inclined scraper 11 maintains a stable angle during scraping, which can effectively remove oil and wax scale on the filter cartridge 10 without damaging the inner wall of the filter cartridge 10. When the filter cartridge 10 is installed inside the water washing tower 9, it can be inserted into the fixing groove 26 for quick installation.

[0030] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

[0031] In the description of this patent, it should be understood that the terms “center,” “upper,” “lower,” “front,” “back,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this patent and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this patent.

Claims

1. An anti-clogging device for methanol-to-olefins production, characterized in that, The system includes a water washing tower (9), a water washing pump (8), and a C5 refueling assembly, characterized in that: The C5 refueling assembly includes a C5 self-separation unit pipeline (1), a fuel oil / C5 flow meter (2), a fuel oil tank inlet pipeline regulating valve (3), a C5 to inlet pipeline (4), a fuel oil pump (5), a fuel oil pump outlet pressure control valve (6), and a C5 to water wash pump inlet pipeline (7) connected in sequence, thereby forming a continuous refueling path; The washing tower (9) is equipped with a rotary wax scraping assembly. The rotary wax scraping assembly includes a filter cylinder (10) installed inside the washing tower (9) and an inclined scraper (11) that contacts the inner wall of the filter cylinder (10). The top of the washing tower (9) is connected to a water inlet pipe (12), and the bottom of the washing tower (9) is connected to a water outlet pipe (13). The bottom of the washing tower (9) is provided with a bottom cover (14). An opening assembly is provided between the bottom cover (14) and the washing tower (9). The top of the washing tower (9) is fixedly installed with a top cover (15) by bolts.

2. The anti-clogging device for methanol-to-olefins according to claim 1, characterized in that, The rotary scraper assembly also includes a motor (16) fixedly installed on the upper surface of the top cover (15). A rotating rod (17) is fixedly installed at the output end of the motor (16). Several bushings (18) are fixedly installed on the rotating rod (17). A sleeve (19) is fixedly installed on one side of the bushing (18). A sliding rod (20) is slidably installed inside the sleeve (19). A spring (21) is fixedly installed between the sliding rod (20) and the sleeve (19). The inclined scraper (11) is fixedly installed on the sliding rod (20).

3. The anti-clogging device for methanol-to-olefins according to claim 1, characterized in that, The inclined scraper (11) is distributed in a spiral along the axis of the rotating rod (17).

4. The anti-clogging device for methanol-to-olefins according to claim 2, characterized in that, The inner wall of the sleeve (19) is provided with a groove (22), and a slider (23) is slidably installed in the groove (22). The slider (23) is fixedly connected to the slide rod (20).

5. The anti-clogging device for methanol-to-olefins according to claim 1, characterized in that, Inside the water washing tower (9), near the bottom, there are several fixed blocks (24) arranged in a ring array. Fixed rings (25) are fixedly installed between the fixed blocks (24). A fixed groove (26) matching the filter cartridge (10) is provided above the fixed rings (25).

6. The anti-clogging device for methanol-to-olefins according to claim 1, characterized in that, The lowest point of the outlet pipe (13) is higher than the lowest point of the filter cartridge (10).

7. The anti-clogging device for methanol-to-olefins according to claim 1, characterized in that, The opening assembly includes a connecting seat (27) fixedly installed on the outer wall of the water washing tower (9). The connecting seat (27) includes an upper seat (28) and a lower seat (29) with an included angle of 90 degrees. A first opening (30) is provided on one side of the upper seat (28). A cylinder (31) is rotatably installed at the first opening (30) via a rotating shaft. A second opening (32) is provided on one side of the lower seat (29). A connecting plate (33) is rotatably installed at the second opening (32) via a rotating shaft. A U-shaped plate (34) is fixedly installed on one side of the connecting plate (33). The included angle between the connecting plate (33) and the U-shaped plate (34) is an obtuse angle. The output end of the cylinder (31) is rotatably connected to the U-shaped plate (34).

8. The anti-clogging device for methanol-to-olefins according to claim 1, characterized in that, A sealing strip (35) is fixedly installed on the bottom cover (14), and the sealing strip (35) is in contact with the inner wall of the water washing tower (9).

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