Controllable flow guide device for wet desulfurization and mist eliminator flushing water

Abstract

The application discloses a wet desulfurization and mist eliminator flushing water controllable flow guide device, which comprises a water collecting tank arranged between a mist eliminator layer and a desulfurization spraying layer and used for receiving the mist eliminator flushing water, a water outlet pipe in communication with a low side end of the water collecting tank, and a shunt pipeline comprising a drainage pipeline and a backflow pipeline. The application automatically switches the flushing water flow direction by a floating member with the liquid level rising and falling, i.e. automatically discharges when the liquid level is high and automatically backflows when the liquid level is low, so that the water inflow in the tower is controlled from the source, the liquid level overrun caused by the flushing water continuously flowing in under the low load working condition is avoided, the mist eliminator is ensured to be continuously flushed without operation according to the normal period, the mist elimination effect is ensured, a pure mechanical type buoyancy self-driven structure is adopted, an external power supply and a control system are not needed, the failure rate is low, the counterweight in the buoyancy cavity can be flexibly increased or decreased, different predetermined liquid level setting requirements are adapted, and on-site adjustment is convenient. Meanwhile, the double-layer staggered arrangement of the water collecting tank is high in collection efficiency and does not affect the normal circulation of flue gas.

Description

Technical Field

[0001] This invention relates to the field of flow control device technology, and in particular to a controllable flow control device for flushing water in a wet desulfurization demister. Background Technology

[0002] The wet limestone-gypsum flue gas desulfurization system is a core environmental protection device for ultra-low emissions of flue gas pollutants from coal-fired power plants. The desulfurization absorption tower is the core equipment of the system. A demister is arranged in the upper part of the tower. The demister is used to remove desulfurization slurry and droplets. The demister is equipped with a flushing water system, which periodically sprays clean water to flush the gypsum slurry and flue dust impurities adhering to the demister blades, preventing demister blockage and ensuring the stable operation of the desulfurization system.

[0003] The existing conventional desulfurization tower demister flushing water pipeline design is as follows: all wastewater after demister flushing falls directly into the slurry pool of the lower absorption tower by gravity, becoming one of the water sources for the desulfurization tower system. Under high-load conditions, the boiler has a large coal consumption, and the raw flue gas carries a large amount of flue gas condensate into the absorption tower. At the same time, the consumption of limestone slurry makeup water and process makeup water in the desulfurization system is high, resulting in a large overall water consumption of the absorption tower. The fact that all the flushing water from the demister enters the slurry pool will not cause the liquid level in the tower to exceed the limit. However, during the deep peak shaving and low-load operation of the unit, the boiler flue gas volume decreases significantly, the amount of condensate carried into the tower by the flue gas decreases sharply, and the system slurry evaporation water consumption decreases significantly. However, the demister needs to be continuously and quantitatively flushed according to a predetermined cycle, and a large amount of flushing water continuously flows into the absorption tower slurry pool, directly causing the liquid level in the absorption tower to rise rapidly.

[0004] To control the excessive liquid level in the desulfurization tower and prevent slurry overflow, on-site operators were forced to reduce or suspend the frequency and duration of demister flushing. Without timely flushing, the demister blades accumulated ash and scale, leading to a series of malfunctions such as liquid droplets carried by the outlet flue gas, abnormal gypsum dehydration, and ash accumulation and corrosion of the induced draft fan. Existing desulfurization towers lack a structure that can flexibly divert demister flushing water, making it impossible to dynamically switch the flushing water flow according to unit load and absorber liquid level. The challenge of low-load water balance management is a common technical pain point in existing wet desulfurization units. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings by providing a controllable flow guiding device for flushing water in wet desulfurization and demister processes.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a controllable flow guiding device for flushing water in a wet desulfurization demister, comprising: A water collection tank is installed between the demister layer and the desulfurization spray layer to collect the demister flushing water. The water outlet pipe is connected to the lower end of the water collection tank; Diversion pipeline, connected to the outlet pipe, includes a drainage pipeline and a return pipeline; An automatic switching mechanism is provided in the diversion pipeline to automatically switch the connection between the outlet pipe and the drainage pipeline or the return pipeline according to the change of the liquid level in the absorption tower. The automatic switching mechanism includes a connecting pipe connected to the liquid storage area of ​​the absorption tower, a floating component disposed in the connecting pipe, and a switching valve core disposed on the floating component. The floating component moves up and down with the rise and fall of the liquid level in the absorption tower, thereby driving the switching valve core to switch the connection between the outlet pipe and the drainage pipe or the return pipe.

[0007] Furthermore, the height of the drainage pipe is greater than the height of the return pipe; When the liquid level in the absorption tower is higher than the preset value, the floating component rises under the action of buoyancy, which drives the switching valve core to move upward, so that the water outlet pipe is connected to the drainage pipe, and the flushing water is discharged out of the tower through the drainage pipe. When the liquid level in the absorption tower is lower than the preset value, the floating component descends, causing the switching valve core to move downward, so that the outlet pipe is connected to the return pipe, and the flushing water flows back to the slurry tank of the absorption tower through the return pipe.

[0008] Furthermore, the switching valve core has a reflux port on the side near the reflux pipe and a drain port on the side near the drain pipe. When the liquid level in the absorption tower is lower than the preset value, the reflux port and the reflux pipeline are directly connected. When the liquid level in the absorption tower is higher than the preset value, the drain outlet and the drain pipe are directly connected.

[0009] Furthermore, the water collection tank is provided with two layers, namely a first water collection layer and a second water collection layer. Each water collection layer includes multiple water collection tanks arranged at equal intervals. The water collection tanks on the first water collection layer and the second water collection layer are staggered in the horizontal projection direction.

[0010] Furthermore, the width of a single water collection trough is greater than the distance between two adjacent water collection troughs; Both the first water collection layer and the second water collection layer are inclined toward the side of the water outlet pipe.

[0011] Furthermore, the bottom of the water collection tank is provided with a conical guide surface, with the tip of the conical guide surface facing downwards, in order to guide the flue gas around the bottom of the water collection tank and reduce the direct impact of the flue gas on the bottom of the water collection tank.

[0012] Furthermore, the connecting pipeline is L-shaped, with its horizontal section connected to the side wall of the absorption tower and its vertical section extending along the height of the absorption tower. The floating element is installed in the vertical section of the connecting pipeline, and the lowest point of the horizontal section of the connecting pipeline is located below the design liquid level in the liquid storage area of ​​the absorption tower.

[0013] Furthermore, the floating component has a sealed buoyancy cavity inside, a limiting protrusion is provided on the outer wall of the floating component, and a limiting groove extending in the vertical direction is provided on the inner wall of the connecting pipe. The limiting protrusion is slidably engaged in the limiting groove to restrict the circumferential rotation of the switching valve core.

[0014] The beneficial effects of this invention are reflected in: This invention utilizes a floating component to automatically switch the flow direction of flushing water as the liquid level rises and falls—automatically discharging when the liquid level is high and automatically recirculating when the liquid level is low, requiring no manual intervention. This controls the water inflow into the tower from the source, preventing the liquid level from exceeding limits due to continuous flushing water inflow under low-load conditions. Simultaneously, it ensures the demister operates continuously according to its normal flushing cycle, guaranteeing the demisting effect. It employs a purely mechanical buoyancy self-driven structure, requiring no external power supply or control system, resulting in a low failure rate. The counterweights within the buoyancy chamber can be flexibly added or removed to adapt to different predetermined liquid level settings, facilitating on-site adjustment. Furthermore, the double-layered staggered arrangement of the water collection tank ensures high collection efficiency without affecting the normal flow of flue gas. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the cross-sectional structure of the present invention; Figure 2 This is a three-dimensional structural cross-sectional view of the present invention; Figure 3 This is a side perspective cross-sectional view of the present invention; Figure 4 This is a top view of the water collection tank structure of the present invention; Figure 5 For the present invention Figure 1 Enlarged schematic diagram of the structure at point A in the middle; Figure 6 For the present invention Figure 1 A schematic diagram of another implementation of the structure at point A.

[0016] In the picture: 1. Demister layer; 2. First water collection layer; 21. Water collection tank; 22. Water outlet pipe; 3. Second aquifer; 4. Desulfurization spray layer; 5. Diversion pipes; 51. Drainage pipes; 52. Return pipes; 53. Connecting pipes; 6. Automatic switching mechanism; 61. Floating component; 62. Switching valve core; 621. Return port; 622. Drain port. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figures 1 to 6 As shown, this embodiment provides a controllable flow guiding device for the flushing water of a wet desulfurization demister, which is installed inside the desulfurization absorption tower, between the demister layer 1 and the desulfurization spray layer 4.

[0019] like Figure 1 As shown, a demister layer 1 is arranged in the upper part of the desulfurization absorption tower, and a desulfurization spray layer 4 is arranged below the demister layer 1. A water collection tank 21 is arranged between the demister layer 1 and the desulfurization spray layer 4 to collect the wastewater after demister flushing. The water collection tank 21 has a groove-shaped structure with a conical guide surface at the bottom, with the tip of the conical guide surface facing downwards, to guide the flue gas around the bottom of the water collection tank, reduce the direct impact of the flue gas on the bottom of the water collection tank, and prevent the water collection tank from being worn by long-term flue gas flushing. One side of the water collection tank 21 is higher than the other side. A water outlet pipe 22 is arranged on the lower side, and the water outlet pipe 22 is connected to the lower end of the water collection tank 21, so that the flushing water collected in the water collection tank 21 flows naturally to the water outlet pipe 22 under the action of gravity.

[0020] like Figure 2 and 4 As shown, the water collection tank 21 has two layers: a first water collection layer 2 and a second water collection layer 3. Each water collection layer includes multiple water collection tanks 21 arranged at equal intervals. The water collection tanks 21 on the first water collection layer 2 and the second water collection layer 3 are staggered in the horizontal projection direction, ensuring that the gaps between the upper water collection tanks are covered by the lower water collection tanks. This ensures that the demister flushing water can be collected by at least one water collection tank regardless of where it falls, effectively improving the collection efficiency of the flushing water. The width of a single water collection tank 21 is greater than the distance between two adjacent water collection tanks 21, so that the water collection area coverage of each water collection layer is greater than 50%, ensuring sufficient flushing water collection. Both the first water collection layer 2 and the second water collection layer 3 are inclined towards the outlet pipe 22, that is, the water collection tank 21 has a slope along its length, ensuring that the flushing water can quickly gather at the outlet pipe 22 and avoid the flushing water from stagnating in the water collection tank for a long time.

[0021] like Figure 1 and Figure 3As shown, the outlet pipe 22 is connected to a branch pipe 5. The branch pipe 5 includes a drainage pipe 51 and a return pipe 52. The drainage pipe 51 extends to the outside of the absorption tower and connects to the downstream wastewater treatment unit (such as a collection tank) to discharge the flushing water outside the tower for treatment. The return pipe 52 extends downward and connects to the slurry pool at the bottom of the absorption tower to return the flushing water to the absorption tower slurry pool as a makeup water source for the desulfurization system.

[0022] The diversion pipeline 5 is also equipped with an automatic switching mechanism 6, which is used to automatically switch the connection between the outlet pipe 22 and the drainage pipeline 51 or the return pipeline 52 according to the change of the liquid level in the absorption tower. Figure 2 As shown, the automatic switching mechanism 6 includes a connecting pipe 53, a floating component 61, and a switching valve core 62.

[0023] The connecting pipe 53 is L-shaped, with its horizontal section connected to the side wall of the absorption tower and its vertical section extending along the height of the absorption tower. The lowest point of the horizontal section of the connecting pipe 53 is located below the design liquid level in the liquid storage area of ​​the absorption tower, allowing the slurry in the absorption tower to enter the horizontal section of the connecting pipe 53. A floating element 61 is installed in the vertical section of the connecting pipe 53, and the floating element 61 has a sealed buoyancy chamber inside, allowing it to float up and down with the liquid level. A switching valve core 62 is installed on the floating element 61 and rises and falls together with the floating element 61.

[0024] The switching valve core 62 has a return port 621 on the side near the return pipe 52, and a drain port 622 on the side near the drain pipe 51. The height of the drain pipe 51 is greater than the height of the return pipe 52. For example... Figure 5 As shown, when the absorber level is lower than the preset value, the floating element 61 descends, causing the switching valve core 62 to move downwards, connecting the return port 621 with the return pipeline 52. The outlet pipe 22 connects to the return pipeline 52 through the internal channel of the switching valve core 62, and the flushing water returns to the absorber slurry tank through the return pipeline 52. Figure 6 As shown, when the liquid level in the absorption tower is higher than the preset value, the floating component 61 rises under the action of buoyancy, which drives the switching valve core 62 to move upward, so that the return port 621 and the return pipeline 52 are misaligned and closed. At the same time, the drain port 622 is directly connected to the drain pipeline 51. The water outlet pipe 22 is connected to the drain pipeline 51 through the internal channel of the switching valve core 62, and the flushing water is discharged outside the tower through the drain pipeline 51.

[0025] It should be noted that the buoyancy of the floating component 61 can be flexibly adjusted according to actual usage needs to adapt to different preset liquid level values. Specifically, the sealed buoyancy chamber of the floating component 61 is equipped with a detachable counterweight mounting position. By increasing or decreasing the number or mass of the counterweights, the overall weight of the floating component 61 is changed, thereby adjusting the liquid level height required for the floating component 61 to begin rising. When a lower preset liquid level is required to trigger the switching, reducing the counterweights lightens the total weight of the floating component 61, allowing it to obtain sufficient buoyancy to rise at a lower liquid level. When a higher preset liquid level is required to trigger the switching, increasing the counterweights increases the total weight of the floating component 61, requiring it to rise at a higher liquid level to overcome gravity.

[0026] As another way to adjust the buoyancy of the floating component, the volume of the buoyancy cavity of the floating component 61 can also be configured to be adjustable. For example, an adjusting sleeve that can move axially can be provided on the floating component 61. By rotating the adjusting sleeve, the effective volume of the buoyancy cavity can be changed, thereby changing the displacement volume and maximum buoyancy of the floating component 61. A sealing ring is provided between the adjusting sleeve and the body of the floating component 61 to ensure the airtightness of the buoyancy cavity. When the adjusting sleeve is rotated to move outward, the effective volume of the buoyancy cavity increases and the maximum buoyancy increases, allowing the floating component 61 to float at a lower liquid level; when the adjusting sleeve is rotated to move inward, the effective volume of the buoyancy cavity decreases and the maximum buoyancy decreases, requiring the floating component 61 to float at a higher liquid level.

[0027] As another way to adjust the buoyancy of floating components, buoyancy can be adjusted by replacing floating components 61 with different volumes or materials. Various specifications of floating components 61 are prepared for different desulfurization absorption tower design liquid level operating ranges. Each floating component 61 has different buoyancy characteristics. During on-site installation, the appropriate specification of floating component 61 is selected according to the actual predetermined liquid level requirements.

[0028] It should be noted that, in order to adapt to the adjustment of the floating component 61, the corresponding switching valve core 62 can also be adjusted accordingly to ensure that the return port 621 and the drain port 622 correspond to the return pipe 52 and the drain pipe 51 after the buoyancy changes.

[0029] It should be further explained that the buoyancy setting range of the floating component 61 also needs to overcome the impact force of the water flow discharged from the inside of the outlet pipe 22.

[0030] The outer wall of the floating component 61 is provided with a limiting protrusion, and the inner wall of the connecting pipe 53 is provided with a limiting groove extending in the vertical direction. The limiting protrusion slides in the limiting groove to limit the circumferential rotation of the switching valve core 62, ensuring that the return port 621 and the drain port 622 always maintain the correct alignment with the corresponding return pipe 52 and drain pipe 51 during the lifting and lowering process of the switching valve core 62.

[0031] The working process of this embodiment is as follows: Under high unit load and normal absorber tower liquid level conditions, the slurry consumption and water replenishment demand in the absorber tower are high, while the tower liquid level remains within the normal range. At this time, the liquid level in the connecting pipe 53 is low, the floating element 61 is in the descending position, and the switching valve core 62 moves down accordingly, with the return port 621 directly connected to the return pipe 52. The demister flushing water is collected in the water collection tank 21 and enters the diversion pipe 5 through the outlet pipe 22. It then enters the return pipe 52 through the internal channel of the switching valve core 62 and the return port 621, ultimately returning to the absorber tower slurry pool as a water source for the desulfurization system, meeting the system's water replenishment needs under high load conditions.

[0032] Under conditions of low unit load and high absorber tower liquid level, the boiler flue gas volume decreases significantly, the amount of condensate carried into the tower by the flue gas is drastically reduced, and the system slurry evaporation water consumption is significantly reduced. However, the demister still needs to be continuously flushed according to the predetermined cycle, and a large amount of flushing water continuously flows into the absorber tower slurry pool, causing the absorber tower liquid level to rise rapidly. When the absorber tower liquid level rises to the preset value, the liquid level in the connecting pipe 53 rises accordingly, and the floating component 61 rises under the action of buoyancy, driving the switching valve core 62 to move upward. After the switching valve core 62 moves upward, the return port 621 is misaligned and closed with the return pipe 52, while the drain port 622 is directly connected to the drain pipe 51. After being collected in the water collection tank 21, the demister flushing water enters the diversion pipeline 5 through the outlet pipe 22, then flows through the internal channel of the switching valve core 62 and the drain outlet 622 into the drainage pipeline 51, and is finally discharged outside the tower and sent to the downstream wastewater treatment unit for treatment. It no longer enters the absorption tower slurry pool, thus reducing the amount of water entering the tower at the source, quickly controlling the absorption tower liquid level, and preventing slurry overflow. During this process, the demister flushing operation continues as usual, without needing to reduce or suspend the flushing frequency, ensuring the normal operation of the demister.

[0033] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0034] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0035] Additionally, "multiple" refers to two or more.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A controllable flow guiding device for flushing water in a wet desulfurization demister, characterized in that, include: A water collection tank (21) is set between the demister layer (1) and the desulfurization spray layer (4) to receive demister flushing water; The water outlet pipe (22) is connected to the lower end of the water collection tank (21); The diversion pipe (5) is connected to the outlet pipe (22) and includes a drainage pipe (51) and a return pipe (52). And an automatic switching mechanism (6) is provided in the diversion pipeline (5) for automatically switching the connection between the outlet pipe (22) and the drainage pipeline (51) or the return pipeline (52) according to the change of the liquid level in the absorption tower; The automatic switching mechanism (6) includes a connecting pipe (53) connected to the liquid storage area of ​​the absorption tower, a floating element (61) disposed in the connecting pipe (53), and a switching valve core (62) disposed on the floating element (61). The floating element (61) moves up and down with the rise and fall of the liquid level in the absorption tower, thereby driving the switching valve core (62) to switch the connection between the outlet pipe (22) and the drainage pipe (51) or the return pipe (52).

2. The controllable flow guiding device for flushing water in a wet desulfurization demister according to claim 1, characterized in that: The height of the drainage pipe (51) is greater than the height of the return pipe (52); When the liquid level in the absorption tower is higher than the preset value, the floating component (61) rises under the action of buoyancy, which drives the switching valve core (62) to move upward, so that the water outlet pipe (22) is connected to the drainage pipe (51), and the flushing water is discharged out of the tower through the drainage pipe (51). When the liquid level in the absorption tower is lower than the preset value, the floating component (61) descends, causing the switching valve core (62) to move downward, so that the outlet pipe (22) is connected to the return pipe (52), and the flushing water flows back to the slurry pool of the absorption tower through the return pipe (52).

3. The controllable flow guiding device for flushing water in a wet desulfurization demister according to claim 1, characterized in that: The switching valve core (62) has a return port (621) on the side near the return pipe (52), and a drain port (622) on the side near the drain pipe (51). When the liquid level in the absorption tower is lower than the preset value, the reflux port (621) and the reflux pipeline (52) are directly connected. When the liquid level in the absorption tower is higher than the preset value, the drain outlet (622) and the drain pipe (51) are directly connected.

4. The controllable flow guiding device for flushing water in a wet desulfurization demister according to claim 1, characterized in that: The water collection tank (21) is provided with two layers, namely the first water collection layer (2) and the second water collection layer (3). Each water collection layer includes multiple water collection tanks (21) arranged at equal intervals. The water collection tanks (21) on the first water collection layer (2) and the second water collection layer (3) are staggered in the horizontal projection direction.

5. The controllable flow guiding device for flushing water in a wet desulfurization demister according to claim 4, characterized in that: The width of a single water collection tank (21) is greater than the distance between two adjacent water collection tanks (21); The first water collection layer (2) and the second water collection layer (3) are both inclined toward the side of the water outlet pipe (22).

6. The controllable flow guiding device for flushing water in a wet desulfurization demister according to claim 4, characterized in that: The bottom of the water collection tank (21) is provided with a conical guide surface, with the tip of the conical guide surface facing downward, in order to guide the flue gas around the bottom of the water collection tank and reduce the direct impact of the flue gas on the bottom of the water collection tank.

7. The controllable flow guiding device for flushing water in a wet desulfurization demister according to claim 1, characterized in that: The connecting pipe (53) is L-shaped, with its horizontal section connected to the side wall of the absorption tower and its vertical section extending along the height of the absorption tower. The floating element (61) is installed in the vertical section of the connecting pipe (53), and the lowest point of the horizontal section of the connecting pipe (53) is located below the design liquid level of the liquid storage area of ​​the absorption tower.

8. The controllable flow guiding device for flushing water in a wet desulfurization demister according to claim 7, characterized in that: The floating component (61) has a sealed buoyancy cavity inside. The outer wall of the floating component (61) has a limiting protrusion. The inner wall of the connecting pipe (53) has a limiting groove extending in the vertical direction. The limiting protrusion slides in the limiting groove to limit the circumferential rotation of the switching valve core (62).

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