Backwashing device applied to coal water slurry gasification clarifying tank
By introducing backwashing pipelines and flushing devices into the clarifier, the problem of blockage at the bottom of the clarifier caused by the failure of the electric rake was solved, and self-circulation flushing was achieved, ensuring the stable operation and efficient operation of the coal-water slurry gasification system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 新疆心连心能源化工有限公司
- Filing Date
- 2025-06-05
- Publication Date
- 2026-05-12
AI Technical Summary
In existing coal-water slurry gasification systems, malfunctions of the electric rake feeder cause blockages at the bottom of the clarification tank, slurry accumulation, and deterioration of the ash water quality, preventing the system from operating normally. Furthermore, the lack of effective flushing measures leads to economic losses and high labor intensity.
A backwashing system for a clarifier tank, comprising backwashing pipelines and flushing devices, was designed. The system utilizes the grey water collected by the overflow weir for backwashing, and cleans the bottom of the clarifier tank through the first backwashing pipeline, the second backwashing pipeline, and the flushing devices to prevent sediment buildup and ensure stable operation of the system.
It achieves self-circulating flushing in case of electric rake machine failure, reduces labor intensity, avoids equipment shutdown losses, and ensures stable and efficient operation of the system.
Smart Images
Figure CN224220827U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of coal-water slurry gasification clarification tanks, and is a backwashing device for coal-water slurry gasification clarification tanks. Background Technology
[0002] The slag water treatment unit of the coal-water slurry gasification system mainly takes the black water containing coal ash and slag from the bottom of the gasifier, cyclone separator, and water washing tower. After three-stage flash evaporation concentration, the black water is mixed with flocculant in the first static mixer and then enters the clarification tank. The added flocculant in the clarification tank is used to enhance the settling velocity of solid particles in the concentrated black water. The settled slurry is pumped to a filter press for solid-liquid separation by the bottom material pump of the clarification tank. The filter cake is transported out of the boundary, and the clearer filtrate at the top of the clarification tank flows by gravity into the ash water tank. A low-speed electric rake is installed in the clarification tank to push the settled slurry along the bottom cone of the clarification tank into the slurry discharge outlet at the center of the bottom of the clarification tank.
[0003] The defects of the existing coal-water slurry gasification system slag water device are as follows: (1) The slag water device contains two flash tanks, one in operation and one on standby, and only one clarification tank and electric rake machine are set up. There is no backup measure after the electric rake machine fails. If the electric rake machine fails due to blockage at the bottom of the clarification tank, the slurry cannot be discharged in time and can only accumulate at the bottom of the clarification tank, resulting in no settling space for black water, which leads to a deterioration of the quality of the ash water in the upper part of the clarification tank. The device cannot operate normally and the entire system must be shut down, resulting in economic losses; (2) There is no flushing water system. If flushing is required, fire water must be connected to the observation port at the top of the clarification tank for flushing, which not only wastes fresh water but also has poor flushing effect; (3) If the electric rake machine fails, it is necessary to manually dig mud and clean the inside of the clarification tank before the electric rake machine can be repaired, which is labor-intensive. Summary of the Invention
[0004] This utility model provides a backwashing device for a coal-water slurry gasification clarification tank, which overcomes the shortcomings of the prior art. It can effectively solve the problem that the bottom of the clarification tank is blocked, slurry accumulates, and cannot be discharged due to the failure of the electric rake machine in the existing slag water device, resulting in poor ash water quality and the inability of the device to operate normally.
[0005] The technical solution of this utility model is achieved through the following measures: A backwashing device for a coal-water slurry gasification clarifier includes a first vacuum flash tank, a clarifier, a first static mixer, and a first substrate pump. A first processing pipeline is fixedly connected between the bottom outlet of the first vacuum flash tank and the inlet of the first static mixer. A first dosing pipeline is fixedly connected between the inlet of the first static mixer and the top inlet of the clarifier. A second processing pipeline is fixedly connected between the outlet of the first static mixer and the top inlet of the clarifier. A third processing pipeline is fixedly connected between the first outlet on the left side of the bottom of the clarifier and the inlet of the first substrate pump. The pump outlet is fixedly connected to a fourth treatment pipeline. A flow stabilizer is provided on the inner side of the upper part of the clarification tank. An overflow weir is fixedly installed on the upper side wall of the clarification tank. A grey water overflow pipeline is fixedly connected to the outer side of the upper part of the clarification tank corresponding to the overflow weir position. A first backwash pipeline is fixedly connected between the outer side of the upper part of the clarification tank corresponding to the overflow weir position and the third treatment pipeline. An electric rake is provided on the lower side of the interior of the clarification tank. A second backwash pipeline is fixedly connected to the fourth treatment pipeline. A flushing device is fixedly installed at the outlet end of the second backwash pipeline. The flushing device is located on the outer side of the lower part of the clarification tank. The outlet end of the second treatment pipeline extends to the inner side of the flow stabilizer.
[0006] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution:
[0007] The aforementioned flushing device includes an annular main pipe and flushing branch pipes. The outlet end of the second backwashing pipeline is fixedly connected to the annular main pipe located on the lower outer side of the clarification tank. Several flushing holes are provided at intervals along the circumference on the inner side of the annular main pipe. Each flushing hole is fixedly connected to a flushing branch pipe at a corresponding position on the lower part of the clarification tank. Each flushing branch pipe is equipped with a valve.
[0008] The aforementioned overflow weir includes an annular plate and an overflow cylinder. An annular plate is fixedly installed on the upper side wall of the clarification tank, and an overflow cylinder is fixedly installed on the inner side of the annular plate.
[0009] The above also includes a second vacuum flash tank and a second static mixer. A fifth treatment pipeline is fixedly connected between the bottom outlet of the second vacuum flash tank and the inlet of the second static mixer. A second dosing pipeline is fixedly connected to the inlet of the second static mixer. A sixth treatment pipeline is fixedly connected between the outlet of the second static mixer and the upper inlet of the clarifier. The outlet end of the sixth treatment pipeline extends to the inside of the flow stabilizer.
[0010] The above also includes a second substrate pump, a seventh treatment pipeline is fixedly connected between the second outlet on the right side of the bottom of the clarification tank and the inlet of the second substrate pump, and an eighth treatment pipeline is fixedly connected between the fourth treatment pipeline on the right side of the second backwash pipeline and the outlet of the second substrate pump.
[0011] The upper inlet of the aforementioned clarification tank is also fixedly connected to an external wastewater pipeline, the outlet end of which extends into the inner side of the flow tube, and the bottom outlet of the clarification tank is fixedly connected to a waste liquid discharge pipeline.
[0012] This utility model has a reasonable and compact structure and is easy to use. It innovatively adds a first backwash pipeline, a second backwash pipeline, and a flushing device. When the bottom of the clarification tank is blocked, there is too much mud, or the electric rake cannot operate normally due to a malfunction, the relatively clean ash water collected by the overflow weir is used for backwashing. The ash water collected in the overflow weir is passed through the first backwash pipeline, the fourth treatment pipeline, the second backwash pipeline, and the flushing device to backwash the blocked area at the bottom of the clarification tank, avoiding sediment accumulation that would affect the normal and stable operation of the device. It is simple to put into use, easy to operate, and requires low labor intensity. It achieves self-circulation of flushing and has the characteristics of high efficiency and convenience. Attached Figure Description
[0013] Appendix Figure 1 This is a schematic diagram of the process flow of this utility model.
[0014] Appendix Figure 2 For the appendix Figure 1 A bottom view of the flushing device.
[0015] Appendix Figure 1 The codes in the diagram are as follows: 1 for the first vacuum flash tank, 2 for the second vacuum flash tank, 3 for the first static mixer, 4 for the second static mixer, 5 for the first substrate pump, 6 for the second substrate pump, 7 for the first treatment pipeline, 8 for the second treatment pipeline, 9 for the first dosing pipeline, 10 for the second dosing pipeline, 11 for the third treatment pipeline, 12 for the fourth treatment pipeline, 13 for the clarifier, 14 for the annular plate, 15 for the overflow cylinder, 16 for the electric rake, 17 for the ash water overflow pipeline, 18 for the first backwash pipeline, 19 for the second backwash pipeline, 20 for the annular main pipe, 21 for the flushing branch pipe, 22 for the fifth treatment pipeline, 23 for the sixth treatment pipeline, 24 for the seventh treatment pipeline, 25 for the eighth treatment pipeline, 26 for the external wastewater pipeline, 27 for the waste liquid discharge pipeline, and 28 for the flow stabilizer. Detailed Implementation
[0016] This utility model is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this utility model and the actual situation.
[0017] Unless otherwise specified, all equipment and devices used in this invention are existing and commonly known in the art. For example, the electric rake feeder, the first static mixer, the second static mixer, the first vacuum flash tank, and the second vacuum flash tank are existing and commonly known equipment.
[0018] In this utility model, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1The orientation of the layout is determined by the direction of the map.
[0019] The present invention will be further described below with reference to the embodiments and accompanying drawings:
[0020] Example 1: As shown in the attached document Figure 1 , 2 As shown, the backwashing device applied to the clarifier of the coal-water slurry gasification includes a first vacuum flash tank 1, a clarifier 13, a first static mixer 3, and a first substrate pump 5. A first processing pipeline 7 is fixedly connected between the bottom outlet of the first vacuum flash tank 1 and the inlet of the first static mixer 3. A first dosing pipeline 9 is fixedly connected between the inlet of the first static mixer 3 and the top inlet of the clarifier 13. A second processing pipeline 8 is fixedly connected between the first outlet on the left side of the bottom of the clarifier 13 and the inlet of the first substrate pump 5. A third processing pipeline 11 is fixedly connected between the first outlet on the left side of the bottom of the clarifier 13 and the inlet of the first substrate pump 5. A fourth processing pipeline 12 is fixedly connected to the outlet of the first substrate pump 5. A flow stabilizer 28 is provided on the inner side of the upper part of the clarification tank 13. An overflow weir is fixedly installed on the upper side wall of the clarification tank 13. A grey water overflow pipeline 17 is fixedly connected to the outer side of the upper part of the clarification tank 13 corresponding to the overflow weir position. A first backwash pipeline 18 is fixedly connected between the outer side of the upper part of the clarification tank 13 corresponding to the overflow weir position and the third treatment pipeline 11. An electric rake machine 16 is provided on the lower side inside the clarification tank 13. A second backwash pipeline 19 is fixedly connected to the fourth treatment pipeline 12. A flushing device is fixedly installed at the outlet end of the second backwash pipeline 19. The flushing device is located on the outer side of the lower part of the clarification tank 13. The outlet end of the second treatment pipeline 8 extends to the inner side of the flow stabilizer 28.
[0021] This invention involves mixing black water from the bottom of the first vacuum flash tank 1 with flocculant from the first dosing line 9 in the first static mixer 3, and then sending the mixture to the clarification tank 13. Under the action of the flocculant, the fine solid particles in the black water aggregate to form larger flocs. The cleaner ash water at the top of the clarification tank 13 flows into the overflow weir. The ash water collected in the overflow weir is sent out for further treatment by the ash water overflow line 17. The settled sludge is pushed to the bottom of the clarification tank by the continuously moving electric rake 16. The sludge at the bottom is sent to the subsequent filter press for further treatment by the third treatment line 11 and the fourth treatment line 12.
[0022] This utility model innovatively adds a first backwashing pipeline 18, a second backwashing pipeline 19, and a flushing device. When the bottom of the clarification tank 13 is blocked, there is too much mud, or the electric rake machine 16 cannot operate normally due to a malfunction, the relatively clean ash water collected in the overflow weir is used for backwashing. The relatively clean ash water in the overflow weir is passed through the first backwashing pipeline 18, the third treatment pipeline 11, the fourth treatment pipeline 12, the second backwashing pipeline 19, and the flushing device. The flushing device backwashes the blocked area at the bottom of the clarification tank 13, avoiding sediment accumulation that affects the normal and stable operation of the device. It is simple to put into use, convenient to operate, has low labor intensity, realizes self-circulation of flushing, and has the characteristics of high efficiency and convenience.
[0023] The above-mentioned backwashing device for coal-water slurry gasification clarifiers can be further optimized and / or improved according to actual needs:
[0024] Example 2: Its difference from Example 1 is as follows: (See attached) Figure 1 , 2 As shown, the flushing device includes an annular main pipe 20 and flushing branch pipes 21. The outlet end of the second backwash line 19 is fixedly connected to the annular main pipe 20 located on the lower outer side of the clarification tank 13. Several flushing holes are provided at intervals along the circumference on the inner side of the annular main pipe 20. Each flushing hole is fixedly connected to a corresponding position on the lower part of the clarification tank 13 by a flushing branch pipe 21. Each flushing branch pipe 21 is equipped with a valve.
[0025] According to actual needs, in this device, twelve flushing holes are arranged circumferentially on the inner side of the annular main pipe 20. These twelve flushing holes are fixedly connected to corresponding positions at the bottom of the clarification tank 13 by twelve flushing branch pipes 21. During use, when the bottom of the clarification tank 13 is blocked, there is excessive mud, or the electric rake 16 malfunctions and cannot operate normally, the relatively clean ash water collected in the overflow weir is used for backwashing. Specifically, the backwashing process is as follows: the ash water in the overflow weir flows through the first backwashing pipeline 18, the third treatment pipeline 11, the fourth treatment pipeline 12, the second backwashing pipeline 19, the annular main pipe 20, and the flushing branch pipes 21 to backwash the blocked area at the bottom of the clarification tank 13. Four of the flushing branch pipes 21 are opened alternately each time, and the system is switched after each 4-hour flushing cycle. Each flushing branch pipe 21 is labeled as branch pipe one to branch pipe twelve. The valves on branch pipes one, four, seven, and ten are opened first, while the valves on the remaining branch pipes are closed. The lower part of the clarifier 13 is flushed for 4 hours. Then, the valves on branch pipes 2, 5, 8, and 11 are opened, and the valves on the remaining branch pipes are closed. The lower part of the clarifier 13 is flushed for 4 hours. Next, the valves on branch pipes 3, 6, 9, and 12 are opened, and the valves on the remaining branch pipes are closed. The lower part of the clarifier 13 is flushed for 4 hours. The flushing water flow is maintained by periodically switching through the twelve flushing branch pipes 21. If all twelve flushing branch pipes 21 are opened, the flushing effect will be worse due to the low flushing water flow.
[0026] Example 3: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1 As shown, the overflow weir includes an annular plate 14 and an overflow cylinder 15. The annular plate 14 is fixedly installed on the upper side wall of the clarification tank 13, and the overflow cylinder 15 is fixedly installed on the inner side of the annular plate 14.
[0027] With this setup, after the black water in the clarifier 13 is separated by sedimentation, the cleaner grey water at the top of the clarifier 13 flows into the overflow weir.
[0028] Example 4: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1 , 2 As shown, it also includes a second vacuum flash tank 2 and a second static mixer 4. A fifth treatment pipeline 22 is fixedly connected between the bottom outlet of the second vacuum flash tank 2 and the inlet of the second static mixer 4. A second dosing pipeline 10 is fixedly connected to the inlet of the second static mixer 4. A sixth treatment pipeline 23 is fixedly connected between the outlet of the second static mixer 4 and the upper inlet of the clarifier 13. The outlet end of the sixth treatment pipeline 23 extends to the inside of the flow stabilizer 28.
[0029] During use, the second vacuum flash tank 2 and the second static mixer 4 are used in a one-to-one standby configuration with the first vacuum flash tank 1 and the first static mixer 3. They are switched periodically according to the system maintenance cycle to ensure the normal operation of the device.
[0030] Example 5: It differs from Examples 1 to 3 in that, as shown in the appendix... Figure 1 , 2 As shown, it also includes a second substrate pump 6, a seventh treatment pipeline 24 is fixedly connected between the second outlet on the right side of the bottom of the clarification tank 13 and the inlet of the second substrate pump 6, and an eighth treatment pipeline 25 is fixedly connected between the fourth treatment pipeline 12 on the right side of the second backwash pipeline 19 and the outlet of the second substrate pump 6.
[0031] During use, the second substrate pump 6 is also in standby mode. When the first substrate pump 5 malfunctions and needs to be repaired, the second substrate pump 6 is used to pump out the slurry from the bottom of the clarifier 13. The slurry at the bottom of the clarifier 13 is then sent to the subsequent filter press for further processing via the seventh treatment pipeline 24, the eighth treatment pipeline 25, and the fourth treatment pipeline 12.
[0032] Example 6: Its difference from Examples 1 to 4 is as follows: (See attached) Figure 1 , 2 As shown, the upper inlet of the clarification tank 13 is also fixedly connected to an external wastewater pipeline 26, the outlet end of the external wastewater pipeline 26 extends into the inner side of the flow stabilizer 28, and the bottom outlet of the clarification tank 13 is fixedly connected to a waste liquid discharge pipeline 27.
[0033] During operation, wastewater from other process wastewater pipelines is sent to the settling tank 13 for sedimentation treatment; when the unit is shut down, the water in the settling tank 13 can be drained through the waste liquid discharge pipeline 27.
[0034] Depending on the needs, the pipelines and equipment of the backwashing device for the coal-water slurry gasification clarifier may also be equipped with conventional valves, thermometers and pressure gauges known in the art, as required by production.
[0035] The above technical features constitute the embodiments of this utility model, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.
[0036] The usage process of this utility model embodiment:
[0037] First, the black water containing coal ash in the first vacuum flash tank 1 is concentrated and then sent to the first static mixer 3. At the same time, flocculant is also sent to the first static mixer 3 through the first dosing line 9. The black water containing coal ash and flocculant are mixed in the first static mixer 3 and then sent to the clarification tank 13 through the second treatment line 8. The addition of flocculant can promote the aggregation of fine solid particles in the black water containing coal ash into larger flocs. The settled slurry is pushed into the bottom of the clarification tank 13 by the continuously moving electric rake 16. The slurry at the bottom is pumped out by the first bottom pump 5 and sent to the subsequent filter press for post-processing through the third treatment line 11 and the fourth treatment line 12.
[0038] Next, after sedimentation and separation, the cleaner ash water in the upper part of the clarification tank 13 flows into the overflow weir, and the ash water collected in the overflow weir is sent out by the ash water overflow pipeline 17 for further treatment.
[0039] Finally, when the bottom of the clarification tank 13 is blocked, there is too much mud, or the electric rake machine 16 fails to operate normally, the cleaner ash water in the overflow weir is used for backwashing. Backwashing specifically uses grey water from the overflow weir, which flows through the first backwashing pipeline 18, the third treatment pipeline 11, the fourth treatment pipeline 12, the second backwashing pipeline 19, the ring main pipe 20, and the flushing branch pipes 21 to backwash the blocked area at the bottom of the clarifier 13. Each flushing branch pipe 21 is opened in pairs, with four pipelines in each pair. After flushing for 4 hours, the branches are switched. The flushing branch pipes 21 are labeled as branch pipe one to branch pipe twelve. First, the valves on branch pipe one, branch pipe four, branch pipe seven, and branch pipe ten are opened, and the valves on the remaining branch pipes are closed. The lower part of the clarifier 13 is flushed for 4 hours. Then, the valves on branch pipe two, branch pipe five, branch pipe eight, and branch pipe eleven are opened, and the valves on the remaining branch pipes are closed. The lower part of the clarifier 13 is flushed for 4 hours. Next, the valves on branch pipe three, branch pipe six, branch pipe nine, and branch pipe twelve are opened, and the valves on the remaining branch pipes are closed. The lower part of the clarifier 13 is flushed for 4 hours. This process continues until all twelve flushing branch pipes 21 have completed one round of flushing.
[0040] Because the bottom of the clarifier 13 is blocked and there is a lot of mud, after one round of flushing through the twelve flushing branch pipes 21, close the valves on the first backwash line 18 and the second backwash line 19, and the device can operate normally. If the electric rake 16 malfunctions and requires continuous backwashing to ensure that the mud at the bottom of the clarifier 13 is discharged smoothly and sent to the subsequent filter press for further processing, until the entire system is overhauled (generally once a year), close the valves on the first backwash line 18 and the second backwash line 19, drain the water in the clarifier through the waste liquid drain line 27, and inspect the electric rake 16.
Claims
1. A backwashing device for a coal-water slurry gasification clarification tank, characterized in that... The system includes a first vacuum flash tank, a clarifier, a first static mixer, and a first substrate pump. A first treatment pipeline is fixedly connected between the bottom outlet of the first vacuum flash tank and the inlet of the first static mixer. A first dosing pipeline is fixedly connected to the inlet of the first static mixer. A second treatment pipeline is fixedly connected between the outlet of the first static mixer and the top inlet of the clarifier. A third treatment pipeline is fixedly connected between the first outlet on the left side of the bottom of the clarifier and the inlet of the first substrate pump. A fourth treatment pipeline is fixedly connected to the outlet of the first substrate pump. A flow stabilizer is provided on the inner side of the upper part of the clarifier. An overflow weir is fixedly installed on the upper side wall of the clarifier. A grey water overflow pipeline is fixedly connected to the outer side of the upper part of the clarifier corresponding to the overflow weir. A first backwashing pipeline is fixedly connected to the outer side of the upper part of the clarifier corresponding to the overflow weir and the third treatment pipeline. An electric rake is provided on the lower side of the clarifier. A second backwashing pipeline is fixedly connected to the fourth treatment pipeline. A flushing device is fixedly installed at the outlet of the second backwashing pipeline. The flushing device is located on the outer side of the lower part of the clarifier. The outlet of the second treatment pipeline extends to the inner side of the flow stabilizer.
2. The backwashing device for a coal-water slurry gasification clarifier according to claim 1, characterized in that... The flushing device includes a ring main pipe and flushing branch pipes. The outlet end of the second backwashing pipeline is fixedly connected to the ring main pipe located on the outer side of the lower part of the clarification tank. Several flushing holes are provided at intervals along the circumference on the inner side of the ring main pipe. Each flushing hole is fixedly connected to a flushing branch pipe at a corresponding position in the lower part of the clarification tank. Each flushing branch pipe is equipped with a valve.
3. The backwashing device for a coal-water slurry gasification clarifier according to claim 1 or 2, characterized in that... The overflow weir includes an annular plate and an overflow cylinder. An annular plate is fixedly installed on the upper side wall of the clarifier, and an overflow cylinder is fixedly installed on the inner side of the annular plate. Or / and, it also includes a second vacuum flash tank and a second static mixer. A fifth treatment pipeline is fixedly connected between the bottom outlet of the second vacuum flash tank and the inlet of the second static mixer. A second dosing pipeline is fixedly connected to the inlet of the second static mixer. A sixth treatment pipeline is fixedly connected between the outlet of the second static mixer and the upper inlet of the clarifier. The outlet end of the sixth treatment pipeline extends to the inner side of the flow stabilizer cylinder.
4. The backwashing device for a coal-water slurry gasification clarifier according to claim 1 or 2, characterized in that... It also includes a second substrate pump, a seventh treatment pipeline is fixedly connected between the second outlet on the right side of the bottom of the clarification tank and the inlet of the second substrate pump, and an eighth treatment pipeline is fixedly connected between the fourth treatment pipeline on the right side of the second backwash pipeline and the outlet of the second substrate pump.
5. The backwashing device for a coal-water slurry gasification clarifier according to claim 3, characterized in that... It also includes a second substrate pump, a seventh treatment pipeline is fixedly connected between the second outlet on the right side of the bottom of the clarification tank and the inlet of the second substrate pump, and an eighth treatment pipeline is fixedly connected between the fourth treatment pipeline on the right side of the second backwash pipeline and the outlet of the second substrate pump.
6. The backwashing device for a coal-water slurry gasification clarifier according to claim 1, 2, or 5, characterized in that... The upper inlet of the clarification tank is also fixedly connected to an external wastewater pipeline, the outlet end of which extends into the inner side of the flow tube, and the bottom outlet of the clarification tank is fixedly connected to a waste liquid discharge pipeline.
7. The backwashing device for a coal-water slurry gasification clarifier according to claim 3, characterized in that... The upper inlet of the clarification tank is also fixedly connected to an external wastewater pipeline, the outlet end of which extends into the inner side of the flow tube, and the bottom outlet of the clarification tank is fixedly connected to a waste liquid discharge pipeline.
8. The backwashing device for a coal-water slurry gasification clarifier according to claim 4, characterized in that... The upper inlet of the clarification tank is also fixedly connected to an external wastewater pipeline, the outlet end of which extends into the inner side of the flow tube, and the bottom outlet of the clarification tank is fixedly connected to a waste liquid discharge pipeline.