A multi-stage wet dust and mist removal system and method

Abstract

This application relates to a multi-stage wet dust removal and demisting system and method, comprising: a primary dust removal module performing wet impact dust removal on flue gas; a secondary dust removal module performing water bath dust removal on flue gas; and a tertiary dust removal module performing wire mesh dust removal on flue gas. The primary dust removal module includes a primary dust removal tower with a primary concentration tank at its bottom; a venturi flue extends from the primary dust removal tower and connects to the main inlet pipe, with its lower end submerged in the liquid surface of the primary concentration tank; the secondary dust removal module includes a secondary dust removal tower and a secondary concentration tank, with a spray water bath section within the secondary dust removal tower; the tertiary dust removal module includes a tertiary dust removal tower and a circulating water tank, with a wire mesh dust collector within the tertiary dust removal tower; the supernatant from the primary concentration tank flows into the secondary concentration tank, and the supernatant from the secondary concentration tank flows into the circulating water tank. This system effectively purifies high-temperature, high-humidity, and sticky dust through multiple stages, achieving high dust treatment efficiency and meeting environmental emission requirements.

Description

Technical Field

[0001] This application belongs to the field of industrial waste gas purification technology, and in particular relates to a multi-stage wet dust removal and demisting system and dust removal method. Background Technology

[0002] The dust-laden flue gas generated in the ironmaking process of steel plants, including the chain grate cooling section, drying section, pulverized coal injection workshop, batching room, and mixer, has significant unique characteristics: 1) The dust composition is complex, containing a large amount of alkaline substances such as calcium hydroxide, which easily absorbs moisture, corrodes equipment, and forms scale; 2) It has a high moisture content, accompanied by a large amount of water vapor, which carries extremely fine particulate matter (such as PM2.5); 3) The flue gas is characterized by high temperature, high humidity, and viscosity. These characteristics pose a significant challenge to traditional dust removal technologies. Electrostatic precipitators are sensitive to changes in flue gas conditions (temperature and humidity), and the resistivity of dust is difficult to control, resulting in large fluctuations and instability in dust removal efficiency.

[0003] Although bag filters have high dust removal efficiency, in high humidity environments, the filter bags are prone to "clogging", condensation, and corrosion, which leads to a sharp increase in operating resistance, a significant reduction in filter bag life, and extremely high maintenance costs and replacement frequency.

[0004] Dry dust removal methods are completely incapable of handling flue gas containing sticky dust and saturated water vapor; the equipment is prone to clogging and has extremely low availability.

[0005] Therefore, there is an urgent need to develop a dust removal technology that can operate stably and efficiently with low maintenance costs, targeting the characteristics of high temperature, high humidity, and sticky dust. Summary of the Invention

[0006] The purpose of this application is to provide a multi-stage wet dust removal and demisting system and method. This system and method are specially designed for the treatment of high-temperature, high-humidity, and sticky dust. Through multi-stage purification and layer-by-layer treatment, it can achieve high dust treatment efficiency and meet environmental emission requirements.

[0007] This application provides a multi-stage wet dust and mist removal system, comprising: an inlet main duct for guiding flue gas in; a primary dust removal module connected to the inlet main duct for wet impact dust removal of the flue gas; a secondary dust removal module connected to the primary dust removal module for water bath dust removal of the flue gas after primary dust removal; and a tertiary dust removal module connected to the secondary dust removal module for wire mesh dust removal of the flue gas after secondary dust removal; wherein, an inlet spray section is provided inside the inlet main duct for initial spraying of the flue gas inside the inlet main duct; the primary dust removal module includes a primary dust removal tower and a Venturi flue, and a primary concentration tank is provided inside the bottom of the primary dust removal tower. A Venturi flue is installed inside the primary dust collector tower. The upper end of the Venturi flue extends out of the primary dust collector tower and connects to the main inlet pipe. The lower end of the Venturi flue is submerged in the liquid surface of the primary thickener. The secondary dust collector module includes a secondary dust collector tower and a secondary thickener. The secondary dust collector tower is located above the secondary thickener and is equipped with a spray water bath section. The tertiary dust collector module includes a tertiary dust collector tower and a circulating water tank. The tertiary dust collector tower is located above the circulating water tank and is equipped with a wire mesh dust collector. The supernatant from the primary thickener tank flows into the secondary thickener tank, and the supernatant from the secondary thickener tank flows into the circulating water tank.

[0008] Preferably, the bottom of the secondary dust removal tower is provided with a secondary water collection tank, which is connected to the secondary concentration tank via a pipe; the bottom of the tertiary dust removal tower is provided with a tertiary water collection tank, which is connected to the secondary concentration tank via a pipe; or, a connecting port is provided between the top side of the secondary concentration tank and the top side of the circulating water tank; the top of the secondary concentration tank is provided with a sawtooth-shaped weir, which is set higher than the connecting port, so that the supernatant flows to the circulating water tank through the connecting port.

[0009] Preferably, the diameter of the flue inlet at the upper end of the Venturi flue is the same as the diameter of the main inlet pipe; the edge of the flue gas outlet at the lower end of the Venturi flue is set with uniform serrations.

[0010] Preferably, the top sidewall of the primary thickener is provided with an overflow port, which is higher than the horizontal plane of the flue gas outlet at the lower end of the Venturi flue, so that the flue gas outlet at the lower end of the Venturi flue is always submerged below the liquid surface of the primary thickener; the primary thickener is set higher than the secondary thickener, and the overflow port is connected to the secondary thickener through a pipe.

[0011] Preferably, the primary dust removal module further includes: an inclined plate demister, wherein the inclined plate demister is configured in several groups, and the several groups of inclined plate demisters are distributed at intervals from top to bottom; each group of inclined plate demisters includes several inclined plate demister blades arranged around the circumference of the Venturi flue, one end of each inclined plate demister blade is connected to the outer wall of the Venturi flue, and the other end is connected to the inner wall of the primary dust removal tower, and the inclined plate demister blades are inclined downwards.

[0012] Preferably, the spray water bath section is configured as several layers, which are distributed at intervals from top to bottom; each layer of the spray water bath section includes a secondary spray layer and a trough-type water bath layer, with the trough-type water bath layer correspondingly spaced below the secondary spray layer; the trough-type water bath layer includes upper U-shaped components and lower U-shaped components, the upper U-shaped components are distributed at intervals on the cross-section of the secondary dust removal tower, and the U-shaped openings of the upper U-shaped components face downwards, forming a gas descending channel between two adjacent upper U-shaped components; the lower U-shaped components... The lower U-shaped components are spaced apart on the cross-section of the secondary dust collector, with their U-shaped openings facing upwards. The lower U-shaped components are arranged intersecting with the upper U-shaped components, such that the first gas descending channel is located within the U-shaped opening of the lower U-shaped component, which forms a water tank with a height of 100mm-200mm. A second gas descending channel is formed between two adjacent lower U-shaped components and is located within the U-shaped opening of the upper U-shaped component. The liquid level of the slurry in the water tank of the lower U-shaped component is flush with the top of the lower U-shaped component.

[0013] Preferably, the upper U-shaped component includes an inverted "V"-shaped upper top section, an upper vertical section connecting the two ends of the upper top section and extending vertically downwards, and an upper inclined section connecting the two upper vertical sections and tilting in a direction away from each other; the upper inclined sections of two adjacent upper U-shaped components that are close to each other are arranged in the U-shaped opening of the same lower U-shaped component and are arranged in a direction closer to each other, and the upper inclined section is provided with a plurality of vent holes; the lower U-shaped component includes a "V"-shaped lower top section and a lower vertical section connecting the two ends of the lower top section and extending vertically upwards; the two lower vertical sections of the lower U-shaped component are respectively located in the U-shaped openings of two adjacent upper U-shaped components.

[0014] Preferably, the wire mesh dust collectors are configured in several groups, and the several groups of wire mesh dust collectors are distributed at intervals on the cross-section of the three-stage dust collection tower; each group of wire mesh dust collectors includes a cylindrical body, the inner and outer walls of the body are configured with a perforated plate structure and have a sandwich layer, the sandwich layer being filled with wire mesh packing; the interior of the body is provided with a vertically extending flushing pipe, and the outer wall of the flushing pipe is provided with flushing nozzles facing the wire mesh packing from top to bottom.

[0015] Preferably, the width of the interlayer is set between 50mm and 100mm; the wire diameter of the wire mesh filler is between 0.23mm and 0.28mm; and the mesh size of the wire mesh filler is between 3×2.5×4mm.

[0016] This application also provides a dust removal method using the aforementioned multi-stage wet dust and mist removal system, including the following steps: S1: Dust-laden flue gas is collected and enters the main inlet pipe, where it collides with the mist droplets sprayed from the inlet spray section to achieve initial dust capture; S2: The flue gas carrying droplets is accelerated through the Venturi flue and impacts the slurry surface at the bottom of the primary dust removal tower. Coarse dust particles are captured by the slurry under inertia. The flue gas then flows upward through the inclined plate demister, where the droplets in the flue gas are intercepted and collected into the primary concentration tank. S3: The flue gas after primary treatment enters the secondary dust removal tower, where it collides with and is captured by the mist droplets sprayed from the secondary spray layer. It then enters the trough-type water bath layer for water bath washing. The slurry that captures dust overflows to the secondary water collection tank at the bottom and flows into the secondary thickening tank. S4: The flue gas after secondary treatment enters the tertiary dust removal tower. Through the wire mesh dust collector, the fine dust and water mist in the flue gas are captured by the wire mesh packing and intermittently flushed through the flushing pipe, so that the captured dust is flushed into the tertiary water collection tank at the bottom and flows into the secondary concentration tank. S5: The high-solids slurry in the primary and secondary thickening tanks is pumped to the plate and frame filter press for solid-liquid separation by a slurry pump; the supernatant of the secondary thickening tank overflows into the circulating water tank, and after being pressurized by the circulating pump, it is sent back to the inlet spray section, the secondary spray layer and the flushing pipe for recycling.

[0017] Beneficial effects The multi-stage wet dust and mist removal system provided in this application consists of three dust removal stages: Primary dust removal (wet impact dust collector): This is the initial dust removal stage. Coarse dust particles in the flue gas are adsorbed by spray droplets, and after being accelerated through the Venturi flue, they impact the slurry surface inside the primary dust removal tower. The dust is captured by inertial force, achieving preliminary dust removal and reducing the load on the secondary fine dust removal.

[0018] Secondary dust removal (precision water bath dust removal): This is the core section for improving dust removal efficiency. The flue gas after primary treatment enters this section, where it first passes through a secondary spray layer to atomize and capture remaining dust, and then undergoes forced washing through a trough-type water bath layer. This process section can achieve a washing efficiency of over 90% for fine dust, while ensuring that the subsequent tertiary dust removal section is not easily clogged.

[0019] Tertiary dust removal (ultra-low emission dust removal section): This is the final control section. The core component is a wire mesh dust collector. A dynamic water film is formed on the surface of the wire mesh packing through the flushing pipe, and the captured dust is carried by the water flow into the three-stage water collection tank below. This section ensures that the outlet dust concentration is below 5mg / m³.3 To achieve ultra-low emissions.

[0020] The aforementioned multi-stage wet dust and mist removal system organically combines multiple mechanisms such as spray washing, impact dust removal, water bath dust removal, and wire mesh demisting to achieve multi-stage synergy and high-efficiency purification. Through a three-stage progressive treatment process of "coarse-fine-ultra-low," it achieves extremely high collection efficiency for high-temperature, high-humidity, and sticky dust, ensuring that the final emission consistently reaches ≤5mg / m³. 3 The ultra-low emission standard effectively solves the problems of scaling and clogging in traditional dust collectors, ensuring long-term stable operation of the system and low maintenance costs. Attached Figure Description

[0021] Figure 1 This diagram shows a structural schematic of a multi-stage wet dust removal and demisting system in this embodiment; Figure 2 This diagram shows the structure of the primary dust removal module in this embodiment; Figure 3 This embodiment shows a schematic diagram of the structure of the secondary dust removal module and the tertiary dust removal module; Figure 4 This diagram shows a partial schematic of an inlet spray section installed inside the main inlet pipe in this embodiment. Figure 5 This embodiment shows a schematic diagram of a ring of inclined plate demister blades arranged around the outer periphery of the venturi flue. Figure 6 This diagram shows the structure of the inclined plate demister blade in this embodiment; Figure 7 A schematic diagram of the vertical cross-section of the inclined plate demister blade in this embodiment is shown; Figure 8 This diagram shows the structural schematic of the combination of the upper U-shaped component and the lower U-shaped component in this embodiment; Figure 9 This diagram shows the structure of the upper U-shaped component in this embodiment; Figure 10 This diagram shows the structure of the wire mesh dust collector in this embodiment; Figure 11 This figure shows a top view of the wire mesh dust collector in this embodiment; Figure 12 A schematic diagram of the internal cross-section of the wire mesh dust collector in this embodiment is shown.

[0022] Figure Labels 10. Main inlet pipe; 11. Inlet spray section; 111. Inlet spray pipe; 112. Inlet atomizing nozzle; 20. Primary dust removal module; 21. Primary dust removal tower; 211. Primary flue gas outlet; 22. Venturi flue; 221. Serrated; 23. Primary concentrator; 231. Overflow outlet; 24. Inclined plate demister; 241. Inclined plate demister blades; 25. Outlet flue; 30. Secondary dust removal module; 31. Secondary dust removal tower; 311. 312 Secondary flue gas inlet; 32 Secondary flue gas outlet; 32 Secondary thickener; 321 Connecting port; 322 Sawtooth cofferdam; 323 Center-driven sludge scraper; 324 Step support; 33 Secondary spray layer; 331 Secondary spray pipe; 332 Secondary atomizing nozzle; 34 Trough-type water bath; 341 Upper U-shaped component; 3411 Upper top section; 3412 Upper vertical section; 3413 Upper inclined section; 34131 Vent hole; 34 2. Lower U-shaped component; 3421. Lower top section; 3422. Lower vertical section; 35. Gas descending channel one; 36. Gas descending channel two; 37. Secondary water collection tank; 40. Tertiary dust removal module; 41. Tertiary dust removal tower; 411. Tertiary flue gas inlet; 412. Tertiary flue gas outlet; 42. Circulating water tank; 43. Wire mesh dust collector; 431. Cylinder; 4311. Inner cylinder; 4312. Outer cylinder; 4313. Top mounting plate; 431 31. Circle; 431; 32. Rib plate; 432. Wire mesh packing; 433. Flushing pipe; 434. Flushing nozzle; 435. Swirl blade; 44. Three-stage water collection tank; 45. Guide flue; 46. Air distribution grid plate; 50. Guide plate; 60. Clean water circulation module; 61. Circulation pump; 62. Filter; 70. Solid-liquid separation module; 71. Slurry pump; 72. Plate and frame filter press; 80. Main outlet pipe; 90. Exhaust fan; 100. Chimney. Detailed Implementation

[0023] The technical solutions of this application are further illustrated below through specific embodiments. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0024] Please refer to Figures 1-3As shown in the figure, this embodiment provides a multi-stage wet dust removal and demisting system, the process route of which is: dust collection hood at dust release point (not shown in the figure) → branch pipe → inlet main pipe 10 → primary dust removal module 20 → secondary dust removal module 30 → tertiary dust removal module 40 → outlet main pipe 80 → induced draft fan 90 → chimney 100. The specific system includes: an inlet main duct 10, a primary dust removal module 20, a secondary dust removal module 30, and a tertiary dust removal module 40 connected sequentially along the flue gas flow direction. The inlet main duct 10 is used to collect flue gas and guide it into the subsequent tertiary dust removal stage. An inlet spray section 11 is installed inside the inlet main duct 10 to spray the flue gas inside the inlet main duct 10. The primary dust removal module 20 is connected to the inlet main duct 10 and is used for wet impact dust removal of the flue gas. The secondary dust removal module 30 is connected to the primary dust removal module 20 and is used for water bath dust removal of the flue gas after primary dust removal. The tertiary dust removal module 40 is connected to the secondary dust removal module 30 and is used for wire mesh dust removal of the flue gas after secondary dust removal. The primary dust removal module 20 includes a primary dust removal tower 21 and a Venturi flue 22. The primary dust removal tower 21 has a primary thickening tank 23 inside its bottom for collecting dust-laden slurry, and a primary flue gas outlet 211 on its top side. The Venturi flue 22 is located inside the primary dust removal tower 21, with its upper end extending out of the tower and connecting to the main inlet pipe 10. The lower end of the Venturi flue 22 is submerged in the liquid surface of the primary thickening tank 23. The secondary dust removal module 30 includes a secondary dust removal tower 31, which has a secondary thickening tank 32 for collecting dust-laden slurry. A secondary flue gas outlet 211 is located on its top side. The secondary dust collector 31 has an inlet 311 connected to the primary flue gas outlet 211 of the primary dust collector 21. The secondary dust collector 31 has a secondary flue gas outlet 312 on its bottom side, and a spray water bath section is provided between the secondary flue gas inlet 311 and the secondary flue gas outlet 312. The tertiary dust collector module 40 includes a tertiary dust collector 41, which has a circulating water tank 42. The tertiary dust collector 41 has a tertiary flue gas inlet 411 on its bottom side, connected to the secondary flue gas outlet 312 of the secondary dust collector 31, and a tertiary flue gas outlet 412 on its top side. A wire mesh dust collector 43 is provided between the tertiary flue gas inlet 411 and the tertiary flue gas outlet 412. The supernatant from the primary thickener 23 flows into the secondary thickener 32, and the supernatant from the secondary thickener 32 flows into the circulating water tank 42.

[0025] In this embodiment, the multi-stage wet dust removal and demisting system integrates multiple dust removal methods such as dust agglomeration, step-by-step dust removal, and dust spraying. Through multi-stage purification and layer-by-layer processing, it can achieve high-efficiency dust treatment and meet environmental emission requirements. Specifically, it is divided into three dust removal stages. The first-stage dust removal module 20 is a wet impact dust collector. This stage is the primary dust removal stage. The droplets sprayed from the inlet spray section 11 adsorb the coarse dust particles in the flue gas and then accelerate through the Venturi flue 22 to impact the slurry layer surface of the first-stage thickener 23 at the bottom of the tower, thereby capturing the dust and achieving the effect of preliminary dust removal and reducing the fine dust removal load of the second-stage dust removal module 30. The second-stage dust removal module 30 is a fine water bath dust collector. After the flue gas passes through the first-stage dust removal, it enters the second-stage dust removal tower 31 and is then adsorbed and washed by the droplets sprayed from the water bath section. The fine dust in the flue gas will be washed with a washing efficiency of 90% in this stage, while ensuring that the third-stage dust removal stage does not become clogged. The third-stage dust removal module 40 is the ultra-low dust removal section. The core dust removal component in this section is the wire mesh dust collector 43, which captures fine dust and intermittently washes the wire mesh of the dust collector 43. The water film on the wire mesh flows out after reaching a certain weight. The efficiency of this dust removal section is 5 mg / m³. 3 The following multi-stage wet dust and mist removal system achieves ultra-low emissions. This system organically combines various mechanisms, including primary spray washing, wet impact dust removal, water bath dust removal, and wire mesh demisting, in a specific sequence to achieve multi-stage synergy and high-efficiency purification. Through a three-stage progressive treatment process—coarse, fine, and ultra-low—it achieves extremely high collection efficiency for high-temperature, high-humidity, and sticky dust, ensuring that the final emissions consistently reach ≤5mg / m³. 3 Ultra-low emission standards.

[0026] Please refer to Figure 2 and Figure 4As shown in this embodiment, it should be noted that several inlet spray sections 11 are arranged from top to bottom within the main inlet pipe 10, such as three to four inlet spray sections 11. The specific number of layers can be determined according to the dust content, composition, and system resistance parameters of the flue gas. This embodiment does not impose specific limitations and only shows two inlet spray sections 11 as an example for illustration. Each inlet spray section 11 includes an inlet spray pipe 111 and an inlet atomizing nozzle 112. The inlet spray pipe 111 is arranged horizontally within the main inlet pipe 10, and the inlet atomizing nozzles 112 are spaced apart along the length of the inlet spray pipe 111. The inlet atomizing nozzles 112 are evenly arranged on the cross-section of the main inlet pipe 10. The materials of the inlet spray pipe 111 and the inlet atomizing nozzles 112 are both made of 2205 alloy, which can extend the service life. The working pressure of the inlet atomizing nozzle 112 is set to 1.2-1.5 MPa. Under this pressure, the liquid sprayed from the inlet atomizing nozzle 112 can be fully atomized, with an atomized particle size of about 20-50 μm. The capture efficiency is highest when the atomized particle size is about 10 times the dust particle size. When the atomized particle size is too large, the capture efficiency will decrease due to surface tension. It should be noted that each inlet spray pipe 111 is equipped with a high-efficiency inlet atomizing nozzle 112. When the dust in the flue gas passes through the inlet spray pipe 111, it is captured by the atomized droplets and enters the subsequent primary dust removal module 20. The liquid used here is transported by the circulation pump 61 corresponding to the inlet spray pipe 111, and the installation position of the inlet spray pipe 111 is set inside the inlet main pipe 10. This design facilitates the flow of the sprayed liquid into the primary dust removal tower 21 along the inlet main pipe 10.

[0027] Please refer to Figure 1 and Figure 2As shown in this embodiment, it should be noted that the primary dust removal module 20 consists of a primary dust removal tower 21, a Venturi flue 22, a primary thickener 23, an inclined plate demister 24, and an outlet flue 25. The internal bottom of the primary dust removal tower 21 is set as a cone structure and is set as the primary thickener 23, which is used to collect dust-containing slurry. The Venturi flue 22 here serves as the inlet flue of the primary dust collector 21. The Venturi flue 22 is vertically arranged with a narrow throat, the diameter of which is smaller than its inlet and outlet diameters, used to accelerate the flue gas. The Venturi flue 22 is located inside the primary dust collector 21, with its upper end extending beyond the top of the primary dust collector 21. The diameter of the flue inlet at the upper end is the same as the diameter of the main inlet pipe 10, and the two are connected to each other. The lower end of the Venturi flue 22 is submerged below the slurry layer of the primary thickener 23, and the edge of the flue gas outlet at the lower end is uniformly serrated 221. Of course, the depth to which the lower end of the Venturi flue 22 is submerged in the slurry layer of the primary thickener 23 is limited. If it is too deep, the resistance to the flue gas will be too great, and it will not be able to escape effectively. It should be noted that the Venturi flue 22 serves two purposes: first, it increases the flue gas velocity by 1.5 times, enabling dust particles in the flue gas to accelerate their impact with the slurry layer surface of the primary thickener 23, thus allowing the dust to be submerged in the liquid and captured under the influence of inertial force; second, it forcibly reduces the volume of the flue gas coming from upstream, increasing the probability of collision between droplets and dust in the flue gas, making it easier for dust to be captured by droplets, thus facilitating capture when the flue gas impacts the slurry layer surface. Utilizing the Venturi flue 22 as the inlet flue of the primary dust removal tower 21 naturally accelerates the flue gas velocity to meet process requirements, and by submerging the lower end of the Venturi flue 22 below the slurry layer surface of the primary thickener 23, it prevents the flue gas from directly flowing out from the gap between the lower end of the Venturi flue 22 and the slurry layer surface of the primary thickener 23. In this embodiment, the edge of the flue gas outlet at the lower end of the Venturi flue 22 is set with uniform serrations 221. The purpose is to prevent the flue gas after impact from flowing in the opposite direction and rising along the tower wall of the primary dust removal tower 21, and then passing through the inclined plate demister 24.

[0028] In one example, the top sidewall of the primary thickener 23 is provided with an overflow port 231, which is slightly higher than the horizontal level of the flue gas outlet at the lower end of the Venturi flue 22, so that the flue gas outlet at the lower end of the Venturi flue 22 is always submerged in a shallow position below the slurry layer surface of the primary thickener 23; in addition, the primary thickener 23 is positioned higher than the secondary thickener 32 (e.g., Figure 1As shown in the diagram, the overflow port 231 is connected to the secondary thickener 32 via a pipe. With the above configuration, if the slurry level in the primary thickener 23 rises, when the level exceeds the overflow port 231, the slurry in the primary thickener 23 can flow into the secondary thickener 32 through the pipe. This ensures that the flue gas outlet at the lower end of the Venturi flue 22 is always submerged in a shallow position below the slurry level in the primary thickener 23, guaranteeing that the flue gas can effectively escape while the dust in the flue gas can be effectively captured.

[0029] Please refer to Figure 2 and Figure 5 As shown, it should also be noted that the inclined plate demister 24 is configured in several groups, and the several groups of inclined plate demister 24 are distributed at intervals from top to bottom. Each group of inclined plate demister 24 includes several inclined plate demister blades 241 arranged in a circle around the Venturi flue 22. One end of each inclined plate demister blade 241 is connected to the outer wall of the Venturi flue 22, and the other end is connected to the inner wall of the primary dust removal tower 21. The inclined plate demister blades 241 are set inclined downwards. One end of the inclined plate demister blade 241 is connected to the Venturi flue 22, and the other end is connected to the tower wall of the primary dust removal tower 21. It is set with a certain angle of slope so that the droplets flow down the inclined plate demister blade 241 into the primary concentration tank 23 below. Thus, the inclined plate demister 24 is set to better intercept the dust in the flue gas. Specifically, the flue gas after impact flows in the opposite direction and rises along the tower wall of the primary dust removal tower 21, passing through several layers of inclined plate demisters 24. After the flue gas enters the inclined plate demister 24, the droplets are captured on the surface of the inclined plate demister blade 241 and form a droplet flow. The droplet flow flows down the inclined plate demister blade 241 into the primary concentration tank 23 at the bottom for concentration. Therefore, the dust that is impacted by the liquid surface and captured by the inclined plate demister blade 241 settles in the primary concentration tank 23.

[0030] Please refer to Figure 2 , Figure 5 as well as Figure 6 As shown, in one example, the bending angle of the inclined plate demister blade 241 is 90° (e.g. Figure 7As shown in the diagram, similar to an angle steel setting, the inclined plate demister blades 241 have downward-facing openings. When installed, the inclined plate demister blades 241 are tilted at approximately 20°. They are made of 2205 stainless steel, and each layer is staggered at a certain angle to ensure that the flue gas passes through the staggered gaps while better intercepting the mist droplets in the flue gas. When the flue gas flows backward into the inclined plate demister blades 241, the mist droplets in the flue gas continuously collide with the blades due to inertia, forming a liquid film. When the liquid film accumulates to a certain thickness, it flows into the primary concentration tank 23 at the bottom of the primary dust removal tower 21 along with the tilt angle of the inclined plate demister blades 241, achieving the dust capture effect of the inclined plate demister 24. Here, the inclined plate demister 24 meets the process requirements under low-resistance conditions.

[0031] Please refer to Figure 2 and Figure 3 As shown, it should also be noted that one end of the outlet flue 25 is connected to the primary flue gas outlet 211 on the top side of the primary dust removal tower 21, and the other end of the outlet flue 25 is connected to the secondary flue gas inlet 311 on the top side of the secondary dust removal tower 31. The use of the outlet flue 25 facilitates the introduction of flue gas in the primary dust removal tower 21 into the secondary dust removal tower 31 for water bath dust removal.

[0032] Please refer to Figure 1 and Figure 3 As shown in this embodiment, it should be noted that the secondary dust removal module 30 includes a secondary dust removal tower 31, a secondary thickening tank 32, a spray water bath section, and a secondary water collection tank 37. The secondary thickening tank 32 is a concrete structure and is equipped with a centrally driven sludge scraper 323, which scrapes the dust and sludge settled at the bottom of the secondary thickening tank 32 into the central sludge collection hopper. Its advantages include compact structure, uniform hydraulic load, stable operation, and convenient maintenance. The scraper linear speed of the centrally driven sludge scraper 323 is 1-3 m / min, avoiding disturbance to the settled sludge. The gap between the scraper and the tank bottom is controlled at 5-10 mm, achieving a sludge removal rate of over 98%. The bottom end of the secondary dust removal tower 31 is fixedly mounted on top of the secondary thickening tank 32 via support legs and other structures. This design makes the secondary dust removal tower 31 compact, saving building area. The bottom of the secondary dust collector 31 is configured with two conical structures, and the interior of the two conical structures is a secondary water collection tank 37. The bottom of the secondary water collection tank 37 is connected to the secondary thickening tank 32 through pipes. The spray water bath section is set above the secondary water collection tank 37 and is set in several layers. The several layers of spray water bath sections are distributed at intervals from top to bottom. In this embodiment, only two layers are used as an example for explanation. Each spray water bath section includes a secondary spray layer 33 and a trough-type water bath layer 34. The trough-type water bath layer 34 is set at intervals below the secondary spray layer 33. The purpose of setting the trough-type water bath layer 34 in the secondary dust collector 31 is to wash the flue gas under low resistance conditions.

[0033] Please refer to Figure 3 As shown, in one example, the secondary spray layer 33 includes a secondary spray pipe 331 and secondary atomizing nozzles 332. Multiple secondary atomizing nozzles 332 are arranged at intervals on the secondary spray pipe 331. The secondary spray layer 33 captures dust in the flue gas by colliding the atomized droplets from the secondary atomizing nozzles 332 with the dust particles. Simultaneously, it replenishes water to the corresponding trough-type water bath layer 34 below. Both the secondary spray pipe 331 and the secondary atomizing nozzles 332 are made of 2205 alloy to ensure wear resistance. The spray pressure of the secondary atomizing nozzles 332 is 1.2-1.5 MPa, and the atomized particle size is approximately 20-50 μm, maximizing the capture efficiency.

[0034] Please refer to Figure 3 and Figure 8As shown, in one example, the trough-type water bath layer 34 includes an upper U-shaped component 341 and a lower U-shaped component 342 fixed inside the secondary dust removal tower 31. The upper U-shaped components 341 are spaced apart on the cross-section of the secondary dust removal tower 31, and the U-shaped openings of the upper U-shaped components 341 face downwards. A gas descending channel 35 is formed between two adjacent upper U-shaped components 341. The flue gas flows from top to bottom through the gas descending channel 35 into the lower U-shaped component 342 below. The function of the upper U-shaped component 341 here is to uniformly distribute the flue gas and increase the flue gas pressure, so that the flue gas passes evenly through the water trough formed by the U-shaped opening of the lower U-shaped component 342 below. The lower U-shaped components 342 are spaced apart on the cross-section of the secondary dust collector 31, with their U-shaped openings facing upwards. The lower U-shaped components 342 and the upper U-shaped components 341 are arranged intersectingly to form a water trough with a height of 100mm-200mm. Simultaneously, the gas descending channel 35 is located within the U-shaped opening of the lower U-shaped component 342. Furthermore, a second gas descending channel 36 is formed between two adjacent lower U-shaped components 342 and is located within the U-shaped opening of the upper U-shaped component 341. The liquid level of the slurry within the U-shaped opening of the lower U-shaped component 342 is kept flush with the top of the lower U-shaped component 342. The flue gas flows downwards through the water trough formed by the U-shaped openings of the lower U-shaped components 342, then escapes downwards from the water trough, and finally flows downwards through the second gas descending channel 36 within the U-shaped opening of the upper U-shaped component 341. It can be understood here that the U-shaped opening of the lower U-shaped component 342 can store the circulating water sprayed into the tower through the secondary spray layer 33, forming a water tank. When the flue gas passes through the water tank, it achieves the purpose of washing the flue gas and removing dust. For example, the height of the water tank is about 150mm, and its resistance is 150Pa. In other words, the U-shaped opening of the lower U-shaped component 342 can store spray water to form a water tank 150mm deep. After the flue gas enters the secondary dust removal tower 31, the dust in the flue gas is captured by the droplets sprayed from the secondary spray layer 33 and stabilized in the trough-type water bath layer 34. That is to say, the flue gas is forcibly washed when it passes through the water tank evenly. The dust is further captured in the tank and overflows to the secondary water collection tank 37 at the bottom. The secondary water collection tank 37 then transports the collected dust-containing slurry to the secondary thickening tank 32 at the bottom through pipelines.

[0035] Please refer to Figure 8 and Figure 9As shown, in another example, the upper U-shaped member 341 includes an upper top section 3411 arranged in an inverted "V" shape, an upper vertical section 3412 that connects to both ends of the upper top section 3411 and extends vertically downwards, and an upper inclined section 3413 that connects to the two upper vertical sections 3412 and is inclined in a direction away from each other. The upper inclined sections 3413 of two adjacent upper U-shaped members 341 are arranged in the same lower U-shaped member 342 and are both inserted into the water tank formed by the lower U-shaped member 342. The two upper inclined sections 3413 inserted into the water tank of the same lower U-shaped member 342 are arranged in a direction closer to each other. The upper inclined section 3413 is provided with a number of vent holes 34131. The lower U-shaped component 342 includes a lower top section 3421 arranged in a "V" shape and a lower vertical section 3422 that connects to both ends of the lower top section 3421 and extends vertically upwards. The two lower vertical sections 3422 of the lower U-shaped component 342 extend into the U-shaped openings of two adjacent upper U-shaped components 341 respectively. In other words, the lower vertical sections 3422 of two adjacent lower U-shaped components 342 are arranged close to each other in the U-shaped opening of the same upper U-shaped component 341. It should be noted that within the U-shaped opening of the same lower U-shaped component 342, the upwardly inclined sections 3413 of two adjacent upper U-shaped components 341 are arranged in a converging direction, and the upwardly inclined sections 3413 are provided with vent holes 34131. A gas descending channel 35 is formed between the upper vertical section 3412 and the upwardly inclined section 3413 of the two adjacent upper U-shaped components 341. When the flue gas descends, it must first enter the water tank formed by the lower U-shaped component 342 through the gas descending channel 35. The upwardly inclined section 3413 is inclined. Within the water tank of the lower U-shaped component 342, compared to a single vertical section 3412, the upper inclined section 3413 and the vent 34131 alter the flow direction of the flue gas. While the flue gas flows vertically downwards in the vertical channel (gas descending channel 35), its linear movement is forcibly altered when it encounters the inclined upper section 3413. The inclined structure provides a longer physical path than the vertical structure, forcing the flue gas to follow the slope to enter the water tank or the next stage channel. Simultaneously, the two upper inclined sections 3413 are positioned towards each other; this "V"-shaped constriction design compresses the flue gas from both sides towards the center (the water tank area of ​​the lower U-shaped component 342), increasing the probability of contact between the flue gas and the liquid (the liquid in the water tank). If the upper inclined section 3413 were a completely sealed plate, the flue gas would only be able to bypass the bottom of the plate (the water tank opening), leading to a sudden increase in local resistance. After the ventilation hole 34131 is opened, some of the flue gas can directly penetrate the upper inclined section 3413 (e.g. Figure 9As shown in the diagram, a "bypass" is formed, effectively reducing the resistance to flue gas passage. It should also be noted that although the upper inclined section 3413 has ventilation holes 34131, the holes are typically small and dense, meaning not all flue gas can flow through them (due to the limited total cross-sectional area). Therefore, a portion will pass through the bottom water tank as originally planned. This design achieves stratified airflow, preventing most of the flue gas from concentrating at the bottom outlet. When the flue gas passes through the ventilation holes 34131, it forms a high-speed jet, disturbing the surrounding fluid and enhancing the contact between gas and liquid, and gas and solid, thus improving dust removal efficiency.

[0036] Please refer to Figure 1 and Figure 3 As shown, it should also be noted that a guide plate 50 is installed between the top spray water bath section and the secondary flue gas inlet 311 of the secondary dust removal tower 31. The guide plate 50 is inclined downwards inside the secondary dust removal tower 31, for example, inclined from left to right, that is, the left end of the guide plate 50 is higher than the right end. Guide holes are evenly distributed on the guide plate 50. Through the arrangement of the guide plate 50, the flue gas enters the secondary dust removal tower 31 through the secondary flue gas inlet 311, and then flows evenly downwards through the guiding effect of the guide plate 50.

[0037] The secondary flue gas outlet 312 is located between the secondary water collection tank 37 at the bottom and the spray water bath section. After the flue gas is treated by the spray water bath section from top to bottom, it is introduced into the tertiary dust removal module 40 through the secondary flue gas outlet 312.

[0038] Please refer to Figure 1 and Figure 3As shown in this embodiment, it should be noted that the three-stage dust removal module 40 includes a three-stage dust removal tower 41, a circulating water tank 42, a wire mesh dust collector 43, a three-stage water collection tank 44, a diversion flue 45, and an air distribution grid plate 46. The circulating water tank 42 is a concrete structure. The bottom end of the three-stage dust removal tower 41 is fixedly installed on the top of the circulating water tank 42 by supporting legs and other structures. This design makes the three-stage dust removal tower 41 compact and saves building area. In addition, a connecting port 321 connects the top and side of the secondary thickener 32 and the top and side of the circulating water tank 42. A stepped support 324 is provided near the top edge of the secondary thickener 32, and a sawtooth-shaped weir 322 is installed in the middle of the stepped support 324. The sawtooth-shaped weir 322 is positioned higher than the connecting port 321. The supernatant from the secondary thickener 32 overflows through the sawtooth-shaped weir 322 and flows into the circulating water tank 42 for reuse. The circulating water tank 42 is designed as an open system, which facilitates cooling. This design achieves water resource reuse and saves operating costs. The sawtooth-shaped weir 322 ensures a stable flow of the supernatant, preventing turbulent flow that could cause unsettled dust to enter the circulating water tank 42 with the supernatant. The bottom of the tertiary dust collector 41 is designed with two conical structures, and the interior of these two conical structures is a tertiary water collection tank 44. The bottom of the tertiary water collection tank 44 is connected to the secondary thickener 32 via pipes.

[0039] Please continue to refer to Figure 1 and Figure 3As shown, the bottom side of the three-stage dust removal tower 41 is set as a three-stage flue gas inlet 411. The three-stage flue gas inlet 411 of the three-stage dust removal tower 41 corresponds to the two-stage flue gas outlet 312 of the two-stage dust removal tower 31. A guide flue 45 is connected at the position of the three-stage flue gas inlet 411. The guide flue 45 extends downward at an incline into the interior of the three-stage dust removal tower 41. The flue gas in the two-stage dust removal tower 31 is introduced into the three-stage dust removal tower 41 through the use of the guide flue 45. The wire mesh dust collector 43 and the uniform air grid plate 46 are arranged vertically. The uniform air grid plate 46 is located above the flue gas guide duct 45, and a guide plate 50 is also arranged below the uniform air grid plate 46. The two opposite ends of the guide plate 50 in one direction are fixedly connected to the tower wall of the three-stage dust removal tower 41, and the two opposite ends of the guide plate 50 in the other direction are connected to the tower wall of the three-stage dust removal tower 41 with reinforcing ribs to improve the stability and strength of the guide plate 50. The guide plate 50 is inclined, and the guide holes are evenly arranged on the guide plate 50 to form a grid, which is conducive to the smooth and uniform flow of flue gas. Flue gas enters the tertiary dust collector 41 from the secondary dust collector 31 through the guide flue 45, and then, during its ascent, is guided by the guide plate 50 into the upper uniform gas distribution grid plate 46. The function of the uniform gas distribution grid plate 46 is to evenly distribute the flue gas across the cross-section of the tertiary dust collector 41, preventing uneven flow that would reduce dust removal efficiency. After passing through the uniform gas distribution grid plate 46, the flue gas enters the upper wire mesh dust collector 43. In one example, the uniform gas distribution grid plate 46 is made of stainless steel, approximately 300 mm high, with grid openings of 250 × 250 mm.

[0040] Please refer to Figure 3 and Figure 10As shown, it should also be noted that the wire mesh dust collector 43 is configured in several groups, and the several groups of wire mesh dust collectors 43 are distributed at intervals on the cross-section of the three-stage dust collection tower 41. Each group of wire mesh dust collectors 43 includes a cylindrical body 431, which includes an inner cylindrical body 4311, an outer cylindrical body 4312, and a top mounting plate 4313. The tops of the inner cylindrical body 4311 and the outer cylindrical body 4312 are both open and connected by the top mounting plate 4313. Both the inner cylindrical body 4311 and the outer cylindrical body 4312 are perforated plate structures, for example, both are made of stainless steel Johnson plates. This design has good flue gas penetration, low operating resistance, and the captured droplets fall more smoothly down the Johnson plates into the lower three-stage water collection tank 44. The inner cylinder 4311 is fitted inside the outer cylinder 4312, forming a sandwich between them. The sandwich is filled with wire mesh filler 432, with a width between 50mm and 100mm. The wire diameter of the wire mesh filler 432 is between 0.23mm and 0.28mm, and the mesh size is between 3×2.5×4mm. The wire mesh is made of 316L material, which is less prone to clogging and can operate stably at high temperatures with an operating resistance of less than 250Pa compared to plastic wire mesh. A vertically extending flushing pipe 433 is located at the center of the inner cylinder 4311. The lower end of the flushing pipe 433 is fixed to the bottom of the inner cylinder 4311, and the upper end extends out from the top of the inner cylinder 4311 and passes through the top mounting plate 4313. An external pipe connects to the flushing pipe 433 to provide it with spray water. The outer wall of the flushing pipe 433 is equipped with flushing nozzles 434 facing the wire mesh packing 432 from top to bottom. Both the flushing nozzles 434 and the flushing pipe 433 are made of 316L alloy. The flushing nozzles 434 intermittently flush the internal wire mesh packing 432, washing the captured dust into the lower three-stage water collection tank 44. The wire mesh dust collector 43 achieves a collection efficiency of over 99% for droplets with a particle size ≥3~5μm, ensuring that flue gas dust emissions meet standards. It should be noted that when flue gas passes through the wire mesh packing 432, the extremely fine dust and droplets are intercepted and condensed by the water film on the wire mesh packing 432. The flushing pipe 433 periodically flushes the wire mesh packing 432 through the flushing nozzles 434, flushing the captured dust into the bottom three-stage water collection tank 44, and then leading it to the secondary concentration tank 32. This stage of dust removal efficiency can reach over 99%, ensuring that the outlet dust concentration is below 5mg / m³. 3 .

[0041] In one example, please refer to Figure 10 and Figure 11As shown, a flushing pipe 433, made of 2205 or 316L material, is provided in the middle of the top mounting plate 4313, penetrating the entire component. A circular hole penetrating the upper and lower surfaces is provided in the middle of the top mounting plate 4313. A circle 43131 is fixedly connected inside the circular hole. The outer peripheral wall of the circle 43131 is fitted and fixed to the inner peripheral wall of the circular hole. The height of the circle 43131 is 30mm. The upper end of the circle 43131 is flush with the upper surface of the top mounting plate 4313, and the lower end of the circle 43131 extends beyond the lower surface of the top mounting plate 4313. The upper end of the inner cylinder 4311 is fitted onto the lower end of the circle 43131 and fixedly connected. The upper end of the flushing pipe 433 extends from the center of the circle 43131, and the circle 43131 and the flushing pipe 433 are connected and fixed by several, for example, six, stiffening plates 43132. The stiffening plates 43132 and the circle 43131 are at the same height. One end of the stiffening plate 43132 is connected to the inner wall of the circle 43131, and the other end is connected to the outer wall of the flushing pipe 433. The six stiffening plates 43132 form six fan-shaped grid holes, and the flue gas flows out from the fan-shaped grid holes formed by the stiffening plates 43132. In addition, the bottom structure of the cylinder 431 is the same as the upper structure, except that the fan-shaped grid holes formed by the stiffening plates 43132 are sealed with wire mesh, and the flue gas enters the interior through the wire mesh.

[0042] It should also be noted that, please refer to Figure 10 and Figure 12As shown, the wire mesh dust collector 43 also includes swirl blades 435. To improve gas-liquid separation efficiency and space utilization, the swirl blades 435 are configured with a multi-layer structure along the axial direction (i.e., the airflow direction, i.e., the outward swirling form), such as two or more layers. Each layer consists of several swirl blades 435, which are arranged in a uniform circumferential array between the outer peripheral wall of the flushing pipe 433 and the inner wall of the inner cylinder 4311. Each swirl blade 435 is a guide plate with a certain curvature or planar structure, and its installation is at a certain tilt angle relative to the horizontal plane or axis, preferably in the range of 25° to 45°. This angle is set to balance the airflow resistance and the swirling intensity. The two ends of the swirl blades 435 are fixedly connected to the outer wall of the flushing pipe 433 and the inner wall of the inner cylinder 4311, respectively (e.g., by welding or integral molding). This connection method allows the swirl blades 435 to not only serve as flow guiding elements but also as reinforcing ribs or supporting frames between the flushing pipe 433 and the inner cylinder 4311, significantly enhancing the stability of the central flushing pipe 433 and preventing it from vibrating or shifting under airflow impact. Secondly, specific tapering or twisted gaps naturally form between adjacent swirl blades 435, which constitute the sole or main outlet channel for the dust-laden flue gas. Furthermore, the outward-swirling swirl blades 435 generate an outward inertial force on the liquid droplets contained in the flue gas, throwing the droplets into the wire mesh packing 432 for further dust removal while reducing the moisture content at the system outlet.

[0043] During operation, dust-laden flue gas enters from the sides and bottom of the inner cylinder 4311, flowing upwards. When the flue gas passes through the multi-layered swirl blades 435, the airflow is forced to change its original vertical direction. Due to the tilting and guiding effect of the blades, the airflow is divided and forced to generate strong rotational motion, forming a high-speed swirling field (vortex) inside the inner cylinder 4311. Under the action of centrifugal force, the mist droplets and dust particles (with relatively large mass) entrained in the flue gas are thrown outwards at high speed, deviating from the main airflow line, colliding with and adhering to the wire mesh packing 432 located on the outer side of the blades, and finally converging and falling under the action of gravity or being carried away by the flushing medium; while the purified gas continues to be discharged upwards through the channels between the swirl blades 435.

[0044] Please refer to Figure 3As shown, it should also be noted that a guide plate 50 is fixedly installed above the wire mesh dust collector 43 in the tertiary dust collector tower 41. The guide plate 50 is inclined, for example, the guide plate 50 is inclined from right to left, that is, the right end of the guide plate 50 is higher than the left end, and guide holes are evenly distributed on the guide plate 50. After the flue gas is treated by the wire mesh dust collector 43, it flows evenly through the top guide plate 50 and is discharged from the tertiary flue gas outlet 412. The guide plate 50 in the tertiary dust collector tower 41 and the guide plate 50 in the secondary dust collector tower 31 are set at the same height, and the two form an inverted "V" shape. It can be understood that the flue gas inlet from the primary dust collector tower 21 to the secondary dust collector tower 31 and the flue gas inlet from the secondary dust collector tower 31 to the tertiary dust collector tower 41 are both equipped with guide plates 50 to ensure smooth, uniform and stable flue gas flow.

[0045] Please refer to Figure 1 As shown, the multi-stage wet dust and mist removal system also includes a clean water circulation module 60. The clean water circulation module 60 includes a circulation pump 61 and a filter 62. Water in the circulating water tank 42 can be pumped by the circulation pump 61 to the inlet spray section 11, the secondary spray layer 33, and the wire mesh dust collector 43, forming a closed-loop operation. A filter 62 is installed at the inlet of the circulation pump 61 to intercept a small amount of dust in the circulating water tank 42. The filter 62 has a filtration accuracy of 1.5–4 mm (approximately 5–20 mesh), its function being to prevent dust from abrading the pump body and to prevent dust from being re-introduced into the dust removal system. In one example, two independent circulation pumps 61 are installed. One circulation pump 61 pumps water from the circulating water tank 42 to the flushing pipe 433 of the wire mesh dust collector 43 via a pipeline. The other circulation pump 61 pumps water from the circulating water tank 42 in two separate pipelines to the inlet spray section 11 and the secondary spray layer 33, respectively. By designing a water circulation system, a closed-loop recycling system for production wastewater was achieved, greatly reducing the consumption of fresh water and the discharge of wastewater.

[0046] Please refer to Figure 1 As shown, the multi-stage wet dust and mist removal system also includes a solid-liquid separation module 70. The solid-liquid separation module 70 includes a slurry pump 71 and a plate and frame filter press 72. The dust slurry concentrated at the bottom of the primary thickener 23 and the secondary thickener 32 is pumped by the slurry pump 71 to the plate and frame filter press 72 for solid-liquid separation. The resulting dust cake enters the dust silo for further processing. The plate and frame filter press 72 is hydraulic, with a pressing pressure of 0.6–1.4 MPa, and a high degree of automation. The filter plates are made of stainless steel, offering advantages such as strong corrosion resistance and long service life.

[0047] Please refer to Figure 1 As shown, the multi-stage wet dust and mist removal system also includes an outlet main duct 80, an induced draft fan 90, and a chimney 100. The outlet main duct 80 is connected to the third-stage flue gas outlet 412 on the top side of the third-stage dust removal tower 41 (e.g., Figure 3As shown in the figure, the induced draft fan 90 is installed at the other end of the outlet main pipe 80 and guides the flue gas into the chimney 100 for final discharge.

[0048] The principle of this application: Dust from the discharge points of the chain grate machine's cooling section, the pulverized coal injection workshop, the mixing chamber's feed inlet and discharge outlet, the conveyor belt's receiving and discharge points, and the lime powder silo and dust removal ash silo, etc., enters the branch flue through the dust collection hood. The branch flue merges into the inlet main pipe 10, which then transports the flue gas to the multi-stage wet dust removal and demisting system of this embodiment. The terminal induced draft fan 90 overcomes the pressure difference generated in the collection point dust collection hood, dust flue, and multi-stage dust removal and demisting device, sending the flue gas into the chimney 100 for emission in compliance with standards.

[0049] Specifically, the flue gas is first scrubbed and washed by the inlet spray section 11 in the main inlet pipe 10. After scrubbing and capturing, the flue gas enters the Venturi flue 22 at the inlet of the primary dust collector 21. The Venturi flue 22 accelerates the flue gas to 1.5 times its original flow velocity, which causes the dust in the flue gas to accelerate and collide with the liquid surface of the primary concentration tank 23 at the bottom of the tower. As a result, the dust is captured by the inertial force and then escapes and rises in the opposite direction along the tower wall of the primary dust collector 21. After passing through the inclined plate demister 24, it enters the secondary dust collector 31. The dust removal efficiency of the primary dust collector 21 can reach about 60-70%. After entering the secondary dust collector 31, the flue gas passes through the secondary spray layer 33 and the trough-type water bath layer 34. The dust removal efficiency of the secondary dust collector 31 is about 20-25%. The flue gas enters the tertiary dust collector 41 through the guide flue 45 of the secondary dust collector 31. After being treated by the wire mesh dust collector 43 in the tertiary dust collector 41, it meets the emission standards.

[0050] The above-mentioned system combines wet impact dust removal in the primary dust removal tower 21 with the Venturi flue 22, fine water bath dust removal in the secondary dust removal tower 31 with the secondary spray layer 33 and the trough water bath layer 34, and ultra-low emission dust removal in the tertiary dust removal tower 41 with the wire mesh dust collector 43. This system effectively combines multiple low-resistance dust removal methods to form an integrated multi-stage dust removal device, achieving stable emissions while maintaining low energy consumption.

[0051] The aforementioned primary thickener 23 directly receives the high-solids slurry impacting the liquid surface, serving as a pre-concentration agent through gravity settling. The design of overflowing the supernatant from the secondary thickener 32 into the circulating water tank 42 ensures that the spray layers (inlet spray section 11 and secondary spray layer 33) always use the liquid with the lowest solids content, greatly improving the efficiency of dust capture by the spray droplets (because clear liquid droplets are more easily charged and have better encapsulation than turbid liquid droplets), while also significantly reducing the risk of nozzle clogging.

[0052] This embodiment also provides a dust removal method using a multi-stage wet dust and mist removal system, including the following steps: S1: Dust-laden flue gas is collected and enters the main inlet pipe 10, where it collides with the mist droplets sprayed from the inlet spray section 11 to achieve initial dust capture. S2: The flue gas carrying droplets is accelerated through the Venturi flue 22 and impacts the slurry surface at the bottom of the primary dust removal tower 21. Coarse dust particles are captured by the slurry under inertia. The flue gas then flows upward through the inclined plate demister 24, where the droplets in the flue gas are intercepted and collected into the primary concentration tank 23. S3: The flue gas after primary treatment enters the secondary dust removal tower 31, where it collides with and is captured by the mist droplets sprayed from the secondary spray layer 33. Then it enters the trough-type water bath layer 34 for water bath washing. The slurry that captures dust overflows to the secondary water collection tank 37 at the bottom and flows into the secondary thickening tank 32. S4: The flue gas after secondary treatment enters the tertiary dust removal tower 41. It passes through the wire mesh dust collector 43, where fine dust and water mist in the flue gas are captured by the wire mesh packing 432 and intermittently flushed through the flushing pipe 433. The captured dust is flushed into the tertiary water collection tank 44 at the bottom and flows into the secondary concentration tank 32. S5: The high-solids slurry in the primary thickener 23 and the secondary thickener 32 is transported by the slurry pump 71 to the plate and frame filter press 72 for solid-liquid separation; the supernatant of the secondary thickener 32 overflows to the circulating water tank 42, and after being pressurized by the circulating pump 61, it is sent back to the inlet spray section 11, the secondary spray layer 33 and the flushing pipe 433 for recycling.

[0053] Traditional multi-stage dust removal is often a simple series connection, while the dust removal method of this application utilizes the different physical states (velocity, saturation) of flue gas at different stages to achieve "intelligent" classification of dust.

[0054] S1 stage (inlet spray): utilizes inertial collision to mainly capture relatively large particles.

[0055] S2 stage (Venturi + impact surface): The acceleration of the Venturi flue 22 creates strong turbulence, while the impact surface operation not only utilizes inertia, but also utilizes the bursting of bubbles and splashing of droplets generated when the flue gas impacts the liquid surface to form a secondary capture, which is extremely efficient for medium-sized particles.

[0056] S3 stage (water bath washing): The trough-type water bath layer 34 is actually a forced bubbling process, which forces the flue gas to pass through the liquid layer. It has an excellent interception effect on particles that escaped in the previous stage and hydrophilic particles that have absorbed water.

[0057] Stage S4 (Wire Mesh Dust Removal): Finally, wire mesh filler 432 is used specifically to target submicron particles and aerosols. This physical logic, from large to small, prevents coarse particles from clogging precision components prematurely, minimizing overall energy consumption.

[0058] It is understood that this application has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this application. Furthermore, based on the teachings of this application, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this application. Therefore, this application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this application.

Claims

1. A multi-stage wet dust and mist removal system, characterized in that, include: The main inlet pipe (10) is used to guide the flue gas in; A primary dust removal module (20) is connected to the inlet main pipe (10) and is used to perform wet impact dust removal on the flue gas; The secondary dust removal module (30) is connected to the primary dust removal module (20) and is used to perform water bath dust removal on the flue gas after primary dust removal. The third-stage dust removal module (40) is connected to the second-stage dust removal module (30) and is used to perform wire mesh dust removal on the flue gas after the second-stage dust removal. The inlet main pipe (10) is provided with an inlet spray section (11), which is used to spray the flue gas in the inlet main pipe (10) for the first time. The primary dust removal module (20) includes a primary dust removal tower (21) and a Venturi flue (22). The primary dust removal tower (21) has a primary concentration tank (23) inside its bottom. The Venturi flue (22) is located inside the primary dust removal tower (21). The upper end of the Venturi flue (22) extends out of the primary dust removal tower (21) and connects to the inlet main pipe (10). The lower end of the Venturi flue (22) is submerged in the liquid surface of the primary concentration tank (23). The secondary dust removal module (30) includes a secondary dust removal tower (31) and a secondary concentration tank (32). The secondary dust removal tower (31) is located above the secondary concentration tank (32), and a spray water bath section is provided inside the secondary dust removal tower (31). The three-stage dust removal module (40) includes a three-stage dust removal tower (41) and a circulating water tank (42). The three-stage dust removal tower (41) is located above the circulating water tank (42), and a wire mesh dust collector (43) is installed inside the three-stage dust removal tower (41). The supernatant from the primary thickener (23) flows into the secondary thickener (32), and the supernatant from the secondary thickener (32) flows into the circulating water tank (42).

2. The multi-stage wet dust and mist removal system as described in claim 1, characterized in that, The bottom of the secondary dust removal tower (31) is provided with a secondary water collection tank (37), which is connected to the secondary concentration tank (32) through a pipe; The bottom of the three-stage dust removal tower (41) is provided with a three-stage water collection tank (44), which is connected to the two-stage thickening tank (32) through a pipe. Alternatively, a connecting port (321) is provided between the top side of the secondary thickening tank (32) and the top side of the circulating water tank (42); The top of the secondary thickening tank (32) is provided with a sawtooth-shaped weir (322), which is set higher than the connecting port (321), so that the supernatant flows to the circulating water tank (42) through the connecting port (321).

3. The multi-stage wet dust and mist removal system as described in claim 1, characterized in that, The diameter of the flue inlet at the upper end of the Venturi flue (22) is the same as the diameter of the main inlet pipe (10); The edge of the flue gas outlet at the lower end of the Venturi flue (22) is set with uniform serrations (221).

4. The multi-stage wet dust and mist removal system as described in claim 3, characterized in that, An overflow port (231) is provided on the top side wall of the primary thickener (23). The overflow port (231) is higher than the horizontal plane of the flue gas outlet at the lower end of the Venturi flue (22), so that the flue gas outlet at the lower end of the Venturi flue (22) is always submerged below the liquid surface of the primary thickener (23). The primary thickener (23) is positioned higher than the secondary thickener (32), and the overflow port (231) is connected to the secondary thickener (32) via a pipe.

5. The multi-stage wet dust and mist removal system as described in claim 1, characterized in that, The primary dust removal module (20) also includes: Inclined plate demister (24), wherein the inclined plate demister (24) is configured in several groups, and the several groups of the inclined plate demister (24) are distributed at intervals from top to bottom; Each of the inclined plate demisters (24) includes several inclined plate demister blades (241) arranged around the circumference of the Venturi flue (22). One end of each inclined plate demister blade (241) is connected to the outer wall of the Venturi flue (22), and the other end is connected to the inner wall of the primary dust removal tower (21). The inclined plate demister blades (241) are inclined downwards.

6. The multi-stage wet dust and mist removal system as described in claim 1, characterized in that, The spray water bath section is configured in several layers, and the several layers of the spray water bath section are distributed at intervals from top to bottom; Each of the spray water bath sections includes a secondary spray layer (33) and a trough-type water bath layer (34), with the trough-type water bath layer (34) being arranged at intervals below the secondary spray layer (33); The trough-type water bath layer (34) includes an upper U-shaped component (341) and a lower U-shaped component (342). The upper U-shaped components (341) are spaced apart on the cross-section of the secondary dust removal tower (31), and the U-shaped opening of the upper U-shaped component (341) faces downward. A gas descending channel (35) is formed between two adjacent upper U-shaped components (341). The lower U-shaped components (342) are spaced apart on the cross-section of the secondary dust removal tower (31). The U-shaped openings of the lower U-shaped components (342) face upwards, and the lower U-shaped components (342) and the upper U-shaped components (341) are arranged crosswise so that the first gas descending channel (35) is located inside the U-shaped opening of the lower U-shaped component (342). The U-shaped opening of the lower U-shaped component (342) forms a water tank with a height of 100mm-200mm. A second gas descending channel (36) is formed between two adjacent lower U-shaped components (342) and is located inside the U-shaped opening of the upper U-shaped component (341). The liquid level of the slurry in the water tank of the lower U-shaped part (342) is flush with the top of the lower U-shaped part (342).

7. The multi-stage wet dust and mist removal system as described in claim 6, characterized in that, The upper U-shaped component (341) includes an upper top section (3411) arranged in an inverted "V" shape, an upper vertical section (3412) that connects the two ends of the upper top section (3411) and is arranged vertically downwards, and an upper inclined section (3413) that connects the two upper vertical sections (3412) and is inclined in a direction away from each other; the upper inclined sections (3413) that are close to each other in two adjacent upper U-shaped components (341) are arranged in the U-shaped opening of the same lower U-shaped component (342) and are arranged in a direction closer to each other, and the upper inclined section (3413) is provided with a plurality of vent holes (34131); The lower U-shaped component (342) includes a lower top section (3421) arranged in a "V" shape and a lower vertical section (3422) that connects the two ends of the lower top section (3421) and is arranged vertically upwards; the two lower vertical sections (3422) of the lower U-shaped component (342) are respectively located in the U-shaped openings of two adjacent upper U-shaped components (341).

8. The multi-stage wet dust and mist removal system as described in claim 1, characterized in that, The wire mesh dust collector (43) is configured in several groups, and the several groups of wire mesh dust collectors (43) are distributed at intervals on the cross-section of the three-stage dust removal tower (41); Each of the wire mesh dust collectors (43) includes a cylindrical body (431), the inner and outer walls of which are configured as perforated plate structures and have a sandwich layer, the sandwich layer being filled with wire mesh filler (432). The interior of the cylinder (431) is provided with a vertically extending flushing pipe (433), and the outer wall of the flushing pipe (433) is provided with flushing nozzles (434) facing the wire mesh packing (432) from top to bottom.

9. The multi-stage wet dust and mist removal system as described in claim 8, characterized in that, The width of the interlayer is set between 50mm and 100mm; The wire diameter of the wire mesh filler (432) is between 0.23 mm and 0.28 mm; The mesh size of the wire mesh filler (432) is between 3×2.5×4mm.

10. A dust removal method using a multi-stage wet dust and mist removal system as described in any one of claims 1-9, characterized in that, Includes the following steps S1: After being collected, the dust-laden flue gas enters the main inlet pipe (10) and collides with the mist droplets sprayed from the inlet spray section (11) to achieve preliminary dust capture; S2: The flue gas carrying droplets is accelerated through the Venturi flue (22) and impacts the slurry surface at the bottom of the primary dust removal tower (21). Coarse dust particles are captured by the slurry under inertial action. The flue gas then flows upward through the inclined plate demister (24), where the droplets in the flue gas are intercepted and collected into the primary concentration tank (23). S3: The flue gas after primary treatment enters the secondary dust removal tower (31), where it collides with and is captured by the droplets sprayed from the secondary spray layer (33). It then enters the trough-type water bath layer (34) for water bath washing. The slurry that captures dust overflows to the secondary water collection tank (37) at the bottom and flows into the secondary thickening tank (32). S4: The flue gas after secondary treatment enters the tertiary dust removal tower (41). Through the wire mesh dust collector (43), the fine dust and water mist in the flue gas are captured by the wire mesh packing (432) and intermittently flushed through the flushing pipe (433). The captured dust is flushed into the tertiary water collection tank (44) at the bottom and flows into the secondary concentration tank (32). S5: The high solid content slurry in the primary thickener (23) and the secondary thickener (32) is transported by the slurry pump (71) to the plate and frame filter press (72) for solid-liquid separation; the supernatant of the secondary thickener (32) overflows to the circulating water tank (42), and after being pressurized by the circulating pump (61), it is sent back to the inlet spray section (11), the secondary spray layer (33) and the flushing pipe (433) for recycling.

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