A method and device for removing fine particles from overflow slurry of a gypsum cyclone of a desulfurization system
By installing a densitometer and flocculant at the overflow outlet of the gypsum hydrocyclone, bypass flocculation and solid-liquid separation of the overflow slurry of the gypsum hydrocyclone were achieved, solving the problem of difficult removal of fine particles and improving the operating efficiency and stability of the desulfurization system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN THERMAL POWER RES INST CO LTD
- Filing Date
- 2026-05-06
- Publication Date
- 2026-07-31
AI Technical Summary
In existing limestone-gypsum wet desulfurization systems, fine particles are difficult to remove effectively, leading to blockage of dewatering equipment, high slurry density in the absorption tower, increased operating energy consumption, and low removal efficiency due to reliance on wastewater discharge, making it difficult to meet environmental protection requirements.
By installing a densitometer at the overflow outlet of the gypsum hydrocyclone, the slurry density is monitored, and bypass flocculation and solid-liquid separation are performed when the density exceeds a set threshold. Large flocs are formed using flocculants and then separated in a plate and frame filter press to form filter cakes for discharge.
It improves the efficiency of fine particle discharge, reduces the density of the absorber slurry, improves the gypsum dewatering performance, reduces the frequency of equipment start-ups and shutdowns, and is suitable for retrofitting existing systems.
Smart Images
Figure CN122479481A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flue gas desulfurization and solid-liquid separation technology, specifically relating to a method and apparatus for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system. Background Technology
[0002] With increasingly stringent requirements for flue gas treatment in coal-fired power plants, the limestone-gypsum wet desulfurization process has become the primary technical route for sulfur dioxide control in coal-fired power plant flue gas due to its high desulfurization efficiency, mature operation, and wide applicability. In this process, the absorption tower slurry circulation, gypsum crystallization, slurry classification, and gypsum dehydration and transportation are all interconnected. Slurry quality not only affects the effectiveness of the desulfurization reaction but also the dehydration performance of gypsum byproducts, their utilization, and the safety and economy of the entire desulfurization system. Therefore, maintaining a reasonable particle size distribution, solids content, and density level in the desulfurization slurry remains a crucial technical issue for the stable operation of limestone-gypsum wet desulfurization systems.
[0003] During the long-term operation of a limestone-gypsum wet desulfurization system, a certain proportion of fine particles, especially those with a diameter of less than 10 μm, gradually accumulate in the desulfurization slurry. These fine particles mainly include gypsum crystals that have stopped growing, gypsum crystal particles formed by breakage under the action of stirring, collision, pumping, and nozzle pressure, and a small amount of coal dust particles. Due to their small particle size and the difficulty in settling and separating them, these particles are often difficult to remove effectively during gypsum hydrocyclone classification and subsequent dewatering processes. They tend to return to the absorption tower with the overflow slurry from the gypsum hydrocyclone and continue to accumulate within the system.
[0004] In existing technologies, the aforementioned fine particle enrichment has at least two adverse effects: First, fine particles easily clog dewatering equipment during gypsum dewatering, affecting the air permeability of the filter cloth and leading to an increase in the moisture content of the gypsum filter cake, which in turn affects the transportation and comprehensive utilization of gypsum. Second, fine particles are difficult to separate effectively by conventional primary centrifugal dewatering equipment. After being returned to the desulfurization system, they cause the absorber slurry density to remain high for a long time, which not only affects the desulfurization reaction but also increases the system's energy consumption. When fine particles are not effectively discharged for a long time, the underflow particle size and solids content are low, and the gypsum moisture content may even exceed 20%, while the absorber slurry density will continue to increase, thus affecting the safe and reliable operation of the system. However, existing limestone-gypsum wet desulfurization systems usually do not have a dedicated independent removal device for fine particles in the slurry. Instead, they rely more on the discharge of desulfurization wastewater to carry some fine particles out of the system, which are then discharged as sludge after sedimentation and plate and frame filtration. On the one hand, desulfurization wastewater itself has a low solids content, limiting its ability to remove fine particles and making it difficult to reverse the continuous accumulation of fine particles in the absorber slurry in a timely manner. On the other hand, with increasingly stringent environmental emission standards and management requirements, the discharge volume of desulfurization wastewater is restricted, and relying solely on wastewater discharge is no longer sufficient to meet the actual demand for rapid removal of fine particles. Furthermore, the wastewater treatment process typically requires the addition of chemicals to precipitate heavy metals, leading to the mixing of fine particles with heavy metal sludge and further increasing the complexity of subsequent sludge disposal. For some thermal power plants, relying solely on the desulfurization wastewater route to remove fine particles not only results in low treatment efficiency but also easily leads to persistently high absorber slurry density and continuous deterioration of gypsum dewatering performance, which in severe cases may even affect the continuous operation of the unit.
[0005] Therefore, there is an urgent need to provide a technical solution that can target the removal of fine particles from the overflow slurry of gypsum hydrocyclones, so as to improve the discharge efficiency of fine particles and improve the operating status of the desulfurization system. Summary of the Invention
[0006] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a method and apparatus for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system.
[0007] This invention provides a method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system, comprising the following steps: S1: Monitor the density of the overflow slurry in the overflow outlet pipe of the gypsum hydrocyclone, and when the density of the overflow slurry is higher than the first set threshold, introduce the overflow slurry into the buffer tank; S2: Add flocculant to the overflow slurry in the buffer tank and stir and flocculate the overflow slurry; S3: The slurry after flocculation is transported to a solid-liquid separation device for solid-liquid separation, so that the solid particles in the slurry form a filter cake in the solid-liquid separation device and are discharged through the unloading end. The separated liquid phase is discharged through the filtrate outlet and transported to the wastewater treatment system. S4: When the density of the overflow slurry is detected to be lower than the second set threshold, stop introducing the overflow slurry into the buffer tank, and stop adding flocculant, stirring and solid-liquid separation.
[0008] Furthermore, the overflow slurry is returned to the absorption tower through the overflow outlet pipeline of the gypsum hydrocyclone, and the overflow slurry contains fine solid particles; the fine solid particles are particles with a particle size of less than 10 μm, and the fine solid particles include at least gypsum crystal particles and coal dust particles.
[0009] Specifically, the first set threshold is 1080 kg / m³. 3 The second set threshold is 1050 kg / m³. 3 .
[0010] Specifically, in step S2, the overflow slurry is stirred by a stirring pump located at the buffer tank.
[0011] Preferably, in step S2, the flocculant is polyacrylamide.
[0012] Specifically, the volume of the buffer tank is 80m³. 3 ~100m 3 The solid-liquid separation device is a plate and frame filter press, and the filtration area of the solid-liquid separation device is 200m². 2 .
[0013] Further, before step S4, steps S1 to S3 are executed repeatedly until the overflow slurry density is lower than the second set threshold, at which point step S4 is executed.
[0014] Furthermore, in step S3, the liquid phase first enters the filtrate tank, and then is transported to the wastewater treatment system by the filtrate pump located at the outlet of the filtrate tank.
[0015] Another aspect of the present invention provides a device for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system. This device is suitable for implementing the above-described method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system, comprising: A gypsum hydrocyclone, wherein an overflow outlet pipe is connected to the gypsum hydrocyclone; A density meter is installed on the overflow outlet pipe of the gypsum hydrocyclone; A branch pipe is connected to the overflow outlet pipe of the gypsum hydrocyclone. The buffer tank is connected to the branch pipeline; The dosing and mixing assembly includes a mixing pump, a flocculant dosing device, and a feed pump, all located at the buffer tank. A solid-liquid separation device is connected to the feed pump; The filtrate treatment assembly includes a filtrate tank connected to the filtrate outlet of the solid-liquid separation device and a filtrate pump connected to the filtrate tank. A control unit, connected to the densitometer, the dosing and stirring assembly, and the solid-liquid separation device, is used to control the start and stop of overflow slurry introduction, flocculation treatment, and solid-liquid separation based on the overflow slurry density detected by the densitometer; and A control valve is installed on the branch pipeline, and the control unit is connected to the control valve to control the overflow slurry to be introduced into the buffer tank through the branch pipeline or to stop the introduction.
[0016] Specifically, the control unit controls the system based on the density of the gypsum hydrocyclone overflow slurry detected by the densitometer, and uses the overflow slurry density being higher than a first set threshold as the control basis for starting the system operation, and uses the overflow slurry density being lower than a second set threshold as the control basis for stopping the system operation.
[0017] The beneficial effects of this invention are as follows: This invention monitors the density of the overflow slurry from a gypsum hydrocyclone and performs bypass flocculation and pressure filtration solid-liquid separation when the overflow slurry density exceeds a preset threshold. This allows for the preferential removal of fine particles that return to the absorption tower with the overflow, improving the efficiency of fine particle discharge, slowing down the continuous enrichment of fine particles in the desulfurization system, reducing the density of the absorption tower slurry, improving the gypsum dewatering conditions, and demonstrating good engineering feasibility and application value. Attached Figure Description
[0018] Figure 1 This is a flowchart illustrating the steps of a method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system, according to a specific embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a desulfurization system gypsum hydrocyclone overflow slurry fine particle removal device according to a specific embodiment of the present invention; Figure 3 This is a particle size distribution diagram of the gypsum hydrocyclone feed for a desulfurization system gypsum hydrocyclone overflow slurry fine particle removal device according to a specific embodiment of the present invention. Figure 4 This is a particle size distribution diagram of the gypsum hydrocyclone overflow slurry fine particle removal device of a desulfurization system according to a specific embodiment of the present invention. Figure 5This is a particle size distribution diagram of the underflow of gypsum hydrocyclone in a desulfurization system, which is a specific embodiment of the present invention.
[0019] The components include: 1. gypsum hydrocyclone; 2. densitometer; 3. buffer tank; 4. mixing pump; 5. feed pump; 6. solid-liquid separation device; 7. unloading end; and 8. hydraulic station. Detailed Implementation
[0020] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0021] like Figure 1 As shown in the figure, a method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system, provided by a specific embodiment of the present invention, includes the following steps: S1: Monitor the density of overflow slurry in the overflow outlet pipe of gypsum hydrocyclone 1, and when the overflow slurry density is higher than the first set threshold, introduce the overflow slurry into the buffer tank 3; S2: Add flocculant to the overflow slurry in buffer tank 3 and stir and flocculate the overflow slurry; S3: The slurry after flocculation is transported to the solid-liquid separation device 6 for solid-liquid separation, so that the solid particles in the slurry form a filter cake in the solid-liquid separation device 6 and are discharged through the discharge end 7. The separated liquid phase is discharged through the filtrate outlet and transported to the wastewater treatment system. S4: When the density of the overflow slurry is detected to be lower than the second set threshold, stop introducing the overflow slurry into the buffer tank 3, and stop adding flocculant, stirring and solid-liquid separation.
[0022] In one embodiment, the first and second set thresholds are set according to the density change of the overflow slurry of the gypsum hydrocyclone 1 and the degree of fine particle enrichment, so that when the fine particles are overflowed and returned to the absorption tower and show a tendency to enrich, the fine particle removal process is started in time; after the density of the overflow slurry recovers to a low level, the fine particle removal process is stopped, and the fine particles are the small solid particles mentioned in the steps.
[0023] Preferably, the first set threshold is greater than the second set threshold, so that the system is put into operation and stopped to correspond to different density ranges, thereby reducing the possibility of frequent equipment start-up and shutdown.
[0024] Furthermore, the overflow slurry monitored in step S1 is the slurry that returns to the absorption tower after being classified by the gypsum hydrocyclone 1. Selecting this overflow branch as the treatment target can preferentially remove the fine particles returning to the absorption tower.
[0025] Based on the above basic implementation method, the overflow slurry returns to the absorption tower through the overflow outlet pipeline of the gypsum hydrocyclone 1, and the overflow slurry contains fine solid particles; the fine solid particles are particles with a particle size of less than 10 μm, and the fine solid particles include at least gypsum crystal particles and coal dust particles; the first set threshold is 1080 kg / m³. 3 The second set threshold is 1050 kg / m³. 3 .
[0026] Furthermore, when the gypsum hydrocyclone 1 classifies the slurry, smaller particles are more likely to be carried out with the overflow slurry and return to the absorption tower, while larger particles are more likely to enter the underflow. Therefore, by bypassing the overflow slurry, the return path of fine particles can be cut off first.
[0027] Furthermore, by combining density monitoring with bypass removal, fine particles can be selectively removed without fully treating the main circulating slurry of the absorber, thus slowing down or reversing the continuous enrichment trend of fine particles in the absorber slurry.
[0028] In one specific embodiment, in step S2, the overflow slurry is stirred by a stirring pump 4 located at the buffer tank 3; the flocculant is polyacrylamide.
[0029] In this embodiment, after the polyacrylamide is added to the buffer tank 3, it comes into contact with the fine solid particles in the overflow slurry and forms larger flocs, so that the solid phase can be retained by the subsequent solid-liquid separation device 6. The polyacrylamide is added to the buffer tank in the form of a prepared flocculant solution and comes into full contact with the overflow slurry under stirring conditions, so as to promote the formation of larger flocs from the fine solid particles in the overflow slurry, which facilitates the subsequent solid-liquid separation.
[0030] Furthermore, the stirring pump continuously circulates and stirs the slurry in the buffer tank 3, so that the overflow slurry comes into full contact with the flocculant and keeps the slurry in the buffer tank 3 in a uniform state. Then, it is transported to the solid-liquid separation device 6 by the feed pump 5.
[0031] In another specific embodiment, the volume of the buffer box 3 is 80m³. 3 ~100m 3 The solid-liquid separation device 6 is a plate and frame filter press, and the filtration area of the solid-liquid separation device 6 is 200m². 2 .
[0032] In this embodiment, the buffer tank 3 is used to receive the gypsum hydrocyclone overflow slurry introduced through the branch pipeline, and to provide buffer space for flocculant addition, slurry mixing and subsequent continuous feeding.
[0033] Specifically, in one application, the plate and frame filter press serves as a solid-liquid separation device 6 to filter and dewater the slurry after flocculation treatment, so that the solid phase in the slurry forms a filter cake inside the plate and frame filter press and is discharged from the discharge end.
[0034] Furthermore, in a specific application, the filtration area is 200m². 2 The plate and frame filter press can produce up to 12 t / h of filter cake with a solid content of about 50%, corresponding to a solid discharge rate of about 6 t / h, thereby increasing the fine particle discharge rate.
[0035] In another specific embodiment, before step S4, steps S1 to S3 are executed repeatedly until the overflow slurry density is lower than the second set threshold and then step S4 is executed.
[0036] Furthermore, when the density meter 2 detects that the density of the overflow slurry is higher than the first set threshold, the control unit opens the control valve and starts the flocculant addition, stirring and solid-liquid separation.
[0037] Specifically, as fine particles are continuously removed from the system, the density of the overflow slurry gradually decreases; when the density meter 2 detects that the density of the overflow slurry is lower than the second set threshold, the control unit closes the control valve and stops the flocculant addition, stirring and solid-liquid separation.
[0038] In another specific embodiment, in step S3, the liquid phase first enters the filtrate tank, and then is transported to the wastewater treatment system by the filtrate pump located at the outlet of the filtrate tank.
[0039] Furthermore, the filtrate tank is used to receive the liquid phase separated by the solid-liquid separation device and to temporarily store and buffer the liquid phase. The power of the solid-liquid separation device 6 is provided by the hydraulic station 8 connected to the solid-liquid separation device 6.
[0040] Specifically, the filtrate pump transports the liquid phase in the filtrate tank to the wastewater treatment system to achieve integration with the existing wastewater treatment process within the plant.
[0041] In another specific embodiment, such as Figure 2 As shown, a device for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system is provided. This device is suitable for implementing the above-mentioned method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system, including: The system includes: a gypsum hydrocyclone 1 with an overflow outlet pipe; a densitometer 2 installed on the overflow outlet pipe of the gypsum hydrocyclone 1; a branch pipe connected to the overflow outlet pipe of the gypsum hydrocyclone 1; a buffer tank 3 connected to the branch pipe; a dosing and stirring assembly including a stirring pump 4, a flocculant dosing device, and a feed pump 5 installed at the buffer tank 3; a solid-liquid separation device 6 connected to the feed pump 5; a filtrate treatment assembly including a filtrate water tank connected to the filtrate outlet of the solid-liquid separation device 6 and a filtrate water pump connected to the filtrate water tank; a control unit connected to the densitometer 2, the dosing and stirring assembly, and the solid-liquid separation device 6, used to control the start and stop of overflow slurry introduction, flocculation treatment, and solid-liquid separation based on the overflow slurry density detected by the densitometer 2; and a control valve installed on the branch pipe, connected to the control unit, used to control the overflow slurry to be introduced into the buffer tank 3 through the branch pipe or to stop the introduction.
[0042] Furthermore, a density meter 2 is installed on the overflow outlet pipe of the gypsum hydrocyclone 1 to obtain the density signal of the overflow slurry; a control valve is set on the branch pipe to control whether the overflow slurry enters the buffer tank 3; the dosing and stirring assembly and the solid-liquid separation device work together to form a bypass removal unit.
[0043] Furthermore, the filtrate treatment component is connected to the filtrate outlet of the solid-liquid separation device 6, so that the liquid phase is transported to the wastewater treatment system via the filtrate tank and filtrate pump, while the solid phase is discharged in the form of filter cake and can be transported off-site together with gypsum.
[0044] In one specific implementation, the control unit controls the system based on the density of the overflow slurry detected by the densitometer 2 from the gypsum hydrocyclone 1, and uses the overflow slurry density being higher than a first set threshold as the control basis for starting the system operation, and uses the overflow slurry density being lower than a second set threshold as the control basis for stopping the system operation.
[0045] In this embodiment, when the density meter 2 detects that the overflow slurry density of the gypsum hydrocyclone 1 is higher than the first set threshold, the control unit outputs a start signal to control the control valve to open and to control the dosing and stirring assembly and the solid-liquid separation device 6 to start operation; when the density meter 2 detects that the overflow slurry density of the gypsum hydrocyclone 1 is lower than the second set threshold, the control unit outputs a stop signal to control the control valve to close and to control the dosing and stirring assembly and the solid-liquid separation device 6 to stop operation.
[0046] Specifically, when the first set threshold is 1080 kg / m 3 The second threshold is set at 1050 kg / m³. 3 At that time, the newly added fine particle removal system can restore the overflow slurry density to 1060 kg / m³ after approximately 24 hours of continuous operation. 3 The following steps are taken to reduce the density of the absorber slurry and the moisture content of the gypsum.
[0047] In one specific implementation, such as Figure 3 , Figure 4 , Figure 5 The following example illustrates the limestone-gypsum wet desulfurization system of a coal-fired power plant. During operation, the absorber slurry density was higher than normal. Tests were conducted on the feed, overflow, and underflow of gypsum hydrocyclone 1. The median particle size of the feed slurry to gypsum hydrocyclone 1 was 7.06 μm, the solid content was 28.94%, and the density was approximately 1215 kg / m³. 3 The median particle size of the overflow slurry from gypsum hydrocyclone 1 was 6.53 μm, the solid content was 24.03%, and the density was approximately 1160 kg / m³. 3 The median particle size of the underflow slurry from gypsum hydrocyclone 1 was 22.72 μm, and the solid content was 44.59%. The test results showed that a large number of small solid particles returned to the absorption tower with the overflow slurry from gypsum hydrocyclone 1, resulting in a higher slurry density in the absorption tower and affecting subsequent gypsum dewatering.
[0048] In this embodiment, based on the above situation, the following removal method is adopted: First, a density meter 2 is installed on the overflow outlet pipe of the gypsum hydrocyclone 1 to monitor the density of the overflow slurry online. A branch pipe is then led out from the overflow outlet pipe of the gypsum hydrocyclone 1, and this branch pipe is connected to a buffer tank 3. The buffer tank 3 has a volume of 90 m³. 3 A stirring pump (4), a plate and frame filter press feed pump, and a polyacrylamide dosing device are installed at buffer tank 3. The solid-liquid separation device 6 uses a plate and frame filter press with a filtration area of 200 m². 2 The filtrate outlet is connected to the filtrate tank, which is then connected to the wastewater treatment system via a filtrate pump. During operation, the density of the overflow slurry from the gypsum hydrocyclone 1 is continuously monitored. When the density meter 2 detects that the overflow slurry density is higher than 1080 kg / m³... 3 At this time, the control valve on the branch pipeline is opened, allowing the overflow slurry from the gypsum hydrocyclone 1 to be introduced into the buffer tank 3. After entering the buffer tank 3, the overflow slurry is kept flowing and mixed under the action of the stirring pump. Simultaneously, polyacrylamide flocculant is added to the buffer tank 3, causing the fine particles in the overflow slurry to flocculate and form larger flocs. Subsequently, the flocculated slurry is transported to the plate and frame filter press by the plate and frame filter press feed pump for filtration separation. In the plate and frame filter press, the flocculated solid particles are retained and form a filter cake, which is discharged and transported off-site along with the gypsum. The separated liquid phase enters the filtrate tank through the filtrate outlet of the plate and frame filter press, and is then transported to the wastewater treatment system by the filtrate pump. Because this path treats the fine particles enriched in the overflow slurry of the gypsum hydrocyclone 1, it allows for the priority removal of fine particles returning to the absorption tower from the system without treating the entire volume of slurry in the main system.
[0049] Specifically, the plate and frame filter press operates continuously, with a filter cake output of 12 t / h and a solid content of approximately 50%, corresponding to a solid discharge of approximately 6 t / h. Simultaneously, the density of the overflow slurry from gypsum hydrocyclone 1 is continuously monitored online, and the process of "monitoring—introducing into the buffer tank—flocculation—filtration separation" is cyclically executed. When the density meter 2 detects that the overflow slurry density from gypsum hydrocyclone 1 is below 1050 kg / m³... 3 At this time, the flow of overflow slurry into buffer tank 3 was stopped, and the addition of flocculant, stirring, and pressure filtration were also stopped; after continuous operation for about 24 hours, the density of the overflow slurry from gypsum hydrocyclone 1 recovered to 1060 kg / m³. 3 Below, the density of the absorber slurry is reduced, and the increasing trend of gypsum moisture content is alleviated, thereby achieving rapid removal of fine particles from the desulfurization system. Compared to using only 5m... 3 In this embodiment, approximately 0.5 t / h of solid particles are carried out with the desulfurization wastewater discharge. By bypassing the overflow slurry of the gypsum hydrocyclone 1 through pressure filtration separation, the discharge rate of fine particles is significantly improved.
[0050] In summary, this embodiment has at least the following technical effects: This invention provides a bypass removal treatment for the overflow slurry of gypsum hydrocyclone 1, which can preferentially remove fine particles that return to the absorption tower with the overflow, thereby cutting off the return path of fine particles and slowing down the continuous enrichment of fine particles in the desulfurization system. This invention installs a density meter on the overflow outlet pipe of the gypsum hydrocyclone 1, and uses a density of 1080 kg / m³. 3 and 1050kg / m 3 As a control basis for starting and stopping operation, the start-up and shutdown of the fine particle removal system have clear judgment conditions, thus avoiding long-term indiscriminate operation. After the overflow slurry enters the buffer tank, flocculant is added and stirred for flocculation treatment, so that the fine particles in the slurry form larger flocs. Then, solid-liquid separation is carried out by solid-liquid separation device 6, which helps to remove the fine particles that are originally difficult to separate directly from the system in the form of filter cake. After the addition of the fine particle removal system, continuous operation for approximately 24 hours can restore the density of the overflow slurry from gypsum hydrocyclone 1 to 1060 kg / m³. 3 The following measures help reduce the density of the absorber slurry and the moisture content of the gypsum, thereby alleviating the problem of poor gypsum dehydration caused by the enrichment of fine particles. In the existing methods, only 5m 3 The desulfurization wastewater discharge carries away some fine particles from the system, with a solids carry-out amount of about 0.5 t / h. However, when the plate and frame filter press is used to bypass the overflow slurry of the gypsum hydrocyclone 1, the filter cake output can reach 12 t / h, the filter cake solids content is about 50%, and the corresponding solids discharge is about 6 t / h. Therefore, it can reverse the accumulation trend of fine particles in the slurry more quickly. By adding branch pipes, buffer tank 3, flocculation and filter press units to the overflow outlet pipe of gypsum hydrocyclone 1, a relatively independent bypass treatment process is formed. This process can be connected to the existing wastewater treatment system without requiring extensive modifications to the entire absorption tower slurry system, making it easy to implement in the existing desulfurization system.
[0051] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.
Claims
1. A method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system, characterized in that, Includes the following steps: S1: Monitor the density of the overflow slurry in the overflow outlet pipe of the gypsum hydrocyclone, and when the density of the overflow slurry is higher than the first set threshold, introduce the overflow slurry into the buffer tank; S2: Add flocculant to the overflow slurry in the buffer tank and stir and flocculate the overflow slurry; S3: The slurry after flocculation is transported to a solid-liquid separation device for solid-liquid separation, so that the solid particles in the slurry form a filter cake in the solid-liquid separation device and are discharged through the unloading end. The separated liquid phase is discharged through the filtrate outlet and transported to the wastewater treatment system. S4: When the density of the overflow slurry is detected to be lower than the second set threshold, stop introducing the overflow slurry into the buffer tank, and stop adding flocculant, stirring and solid-liquid separation.
2. The method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to claim 1, characterized in that, The overflow slurry returns to the absorption tower through the overflow outlet pipeline of the gypsum hydrocyclone, and the overflow slurry contains fine solid particles; the fine solid particles are particles with a particle size of less than 10 μm, and the fine solid particles include at least gypsum crystal particles and coal dust particles.
3. The method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to claim 1, characterized in that, The first set threshold is 1080 kg / m 3 The second set threshold is 1050 kg / m 3 .
4. The method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to claim 1, characterized in that, In step S2, the overflow slurry is stirred by a stirring pump located at the buffer tank.
5. The method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to claim 1, characterized in that, In step S2, the flocculant is polyacrylamide.
6. The method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to claim 1, characterized in that, The buffer tank has a volume range of 80m³. 3 ~100m 3 The solid-liquid separation device is a plate and frame filter press, and the filtration area of the solid-liquid separation device is 200m². 2 .
7. The method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to claim 1, characterized in that, In step S3, the liquid phase first enters the filtrate tank, and then is transported to the wastewater treatment system by the filtrate pump located at the outlet of the filtrate tank.
8. The method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to any one of claims 1 to 7, characterized in that, Before step S4, steps S1 to S3 are executed repeatedly until the overflow slurry density is lower than the second set threshold, at which point step S4 is executed.
9. A device for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system, characterized in that, The apparatus is suitable for implementing a method for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to any one of claims 1 to 8, comprising: A gypsum hydrocyclone, wherein an overflow outlet pipe is connected to the gypsum hydrocyclone; A density meter is installed on the overflow outlet pipe of the gypsum hydrocyclone; A branch pipe is connected to the overflow outlet pipe of the gypsum hydrocyclone. The buffer tank is connected to the branch pipeline; The dosing and mixing assembly includes a mixing pump, a flocculant dosing device, and a feed pump, all located at the buffer tank. A solid-liquid separation device is connected to the feed pump; The filtrate treatment assembly includes a filtrate tank connected to the filtrate outlet of the solid-liquid separation device and a filtrate pump connected to the filtrate tank. A control unit, connected to the densitometer, the dosing and stirring assembly, and the solid-liquid separation device, is used to control the start and stop of overflow slurry introduction, flocculation treatment, and solid-liquid separation based on the overflow slurry density detected by the densitometer; and A control valve is installed on the branch pipeline and is connected to the control unit. The control valve is used to control the overflow slurry to be introduced into the buffer tank through the branch pipeline or to stop the introduction.
10. The device for removing fine particles from the overflow slurry of a gypsum hydrocyclone in a desulfurization system according to claim 9, characterized in that, The control unit controls the system based on the density of the overflow slurry detected by the densitometer, and uses the overflow slurry density being higher than a first set threshold as the basis for system operation, and the overflow slurry density being lower than a second set threshold as the basis for system shutdown.