A full-condition adjustable flue gas uniform distribution device suitable for desulfurization wastewater drying

Abstract

The application discloses a full-condition adjustable flue gas uniform distribution device suitable for desulfurization wastewater drying, and belongs to the technical field of wastewater zero discharge and flue gas treatment equipment. The distributor comprises a volute and a guide cone. A plurality of independent adjustable top plates in the volute are suspended on the inner side of the top of the volute through a plurality of liftable pull rods, and liftable guide vanes capable of being adjusted in angle are suspended in the guide cone through a conical inner guide vane liftable pull rod, and the pull rod is driven by an external guide vane adjusting and driving mechanism. The height of the top plate and the guide vane is adjusted through linkage, the cross section of the whole flow channel from the flue gas inlet to the outlet is changed, the optimal cyclone flow field in the tower is maintained in the full-condition range, the problem of wall sticking and ash hanging of the drying tower under low load is effectively solved, and the desulfurization wastewater spray drying system can adapt to the deep peak shaving demand of the power plant.

Description

Technical Field

[0001] This invention relates to the field of flue gas treatment equipment technology, specifically to a fully adjustable flue gas distribution device suitable for drying desulfurization wastewater. Background Technology

[0002] The flue gas distributor is a core component of the drying spray tower, commonly used in semi-dry flue gas desulfurization and flue gas deacidification processes in industries such as thermal power, steel, and chemicals. In recent years, it has also been widely applied in zero-discharge processes for desulfurization wastewater in power plants. The flue gas distributor provides a uniform swirling flow field for the drying spray tower, ensuring efficient and uniform contact and mixing between the hot flue gas and the liquid medium.

[0003] Currently, the most commonly used type of flue gas distributor in drying spray towers across various industries is the fixed type. The selection and design of its flow equalization plate, guide vanes, and channel layout are all based on full-load processing capacity. However, this results in poor flow field within the tower during later adjustments to operating conditions, making it unsuitable for lower operating levels. Some adjustable flue gas distributors also exist, but whether automatic or manual, the adjustment strategy involves adjusting the cross-sectional size of the hot air outlet. Some manually adjust the height of the guide vanes at the outlet to regulate the cross-sectional size of the hot air outlet, thereby adjusting the flow velocity of the flue gas at the distributor outlet; others electrically adjust the angle of the guide vanes at the outlet to regulate the cross-sectional size of the hot air outlet, thus regulating the flow velocity of the flue gas at the distributor outlet.

[0004] Fixed flue gas distributors, with their flow equalization plates, guide vanes, and channel layout designed for full-load processing, exhibit poor flow field within the tower when operating conditions are lowered, making them unsuitable for these conditions. In zero-discharge desulfurization wastewater processes, this manifests as poor flue gas flow field within the tower under lower operating conditions, leading to easy ash adhesion and buildup on the tower walls, posing a safety hazard. Therefore, they cannot be used under low-load unit conditions, requiring a complete system shutdown and rendering desulfurization wastewater untreated.

[0005] Currently available patents for adjustable flue gas distributors all employ adjustment strategies based on the cross-sectional size of the hot air outlet. Whether this is achieved by manually adjusting the height of the guide vanes at the outlet or electrically adjusting the angle of the guide vanes, the cross-sectional size of the hot air outlet is adjusted. In later stages of operation, when operating conditions are reduced, the cross-sectional area of ​​the hot air outlet is decreased, increasing the outlet velocity of the flue gas distributor to adapt to low-load conditions.

[0006] However, the principle of a flue gas distributor is that flue gas enters through the inlet (generally, an inlet velocity of 9-13 m / s can maintain a good flow field inside the tower). The flue gas flows in a volute-shaped channel, where the cross-sectional area gradually narrows and the flue gas velocity increases. During the contraction of the volute channel, the flue gas is forced to acquire a rotational component along the tangential direction of the channel due to the gradual change in the cross-section, gradually forming a preliminary swirling flow pattern. This is further accelerated and guided within the guide cone, and after exiting the flue gas distributor, the centrifugal force generated by the rotating airflow maintains a rotating flow field inside the tower that is compatible with the atomized droplets. The principle of this flow field formation cannot be fully guaranteed simply by ensuring the outlet velocity of the flue gas distributor.

[0007] In other words, the adjustable flue gas distributors currently available in patents can play a certain role by reducing the cross-section of the hot air outlet and increasing the outlet velocity of the flue gas distributor, but they are not effective for situations where the load is below 50% or even below 30% in power plant desulfurization wastewater zero discharge processes.

[0008] Meanwhile, to adapt to the power system's regulation needs following the large-scale integration of new energy sources, the government has introduced corresponding deep peak-shaving policies aimed at enhancing the flexible regulation capabilities of power plants, especially coal-fired power units, ensuring the safe and stable operation of the power system, and promoting the consumption of new energy. Many power plants are actively cooperating with these policies. Currently, daytime unit generating loads are low (often as low as 20-30%), preventing the use of the aforementioned flue gas distributor drying towers, resulting in drying system shutdowns. On the other hand, for power plants that already have zero discharge of desulfurization wastewater, environmental approvals generally only include a single circulating water discharge outlet. Other power plants are also gradually advancing their zero-discharge desulfurization wastewater projects. When the drying system shuts down, the desulfurization wastewater has nowhere to be disposed of, leading to the slow accumulation of chloride ions in the desulfurization system, far exceeding the original system's capacity. This raises safety concerns regarding the desulfurization tower system. Summary of the Invention

[0009] To address the aforementioned issues, this invention discloses a fully adjustable flue gas distribution device suitable for drying desulfurization wastewater. By dynamically adjusting the cross-sectional area of ​​the flue gas from the inlet to the outlet of the flue gas distributor, the contraction process of the volute channel can adapt to various loads in the power plant, ensuring its flow velocity and flow field in the flue gas distributor. Ultimately, after the flue gas is ejected from the flue gas distributor, the centrifugal force generated by the rotating airflow maintains a rotating flow field inside the tower that is compatible with the atomized droplets.

[0010] An adjustable flue gas distribution device suitable for drying desulfurization wastewater under all operating conditions includes a volute and a guide cone disposed below the volute. A flue gas inlet is formed on the side wall of the volute, and a flue gas outlet is formed at the bottom of the guide cone. An adjustable top plate is disposed on the inner side of the top of the volute, and a liftable rod is connected above the adjustable top plate. The liftable rod extends upward through the top wall of the volute and is drivenly connected to an electric winch for adjusting the top plate disposed outside the volute. Each electric winch can adjust the length of the rod connected to it, thereby adjusting the height and angle of each top plate. The adjustable rod length of each electric winch also adjusts the height of the inner and outer guide vanes of the guide cone, further changing the flow area of ​​the inner and outer channels of the guide cone.

[0011] The outer air passage inside the guide cone is provided with an outer conical guide vane, and the inner air passage is provided with an inner conical guide vane. Above the outer and inner conical guide vanes, there is a height-adjustable tie rod for the inner conical guide vane. The height-adjustable tie rod for the inner conical guide vane extends upward through the top wall of the guide cone and is connected to the electric winch of the inner conical guide vane located at the top of the guide cone.

[0012] Furthermore, the flue gas passage of the volute has a spiral tapering structure, with its spiral direction consistent with the flue gas flow direction, which is used to guide and enhance the swirling flow.

[0013] Furthermore, the adjustable top plate inside the volute is composed of multiple independent top plate sections spliced ​​together.

[0014] Furthermore, the adjustable top plate inside the volute includes, in sequence from near the flue gas inlet, a first adjustable top plate section, a second adjustable top plate section, a third adjustable top plate section, and a fourth adjustable top plate section.

[0015] Furthermore, the first and second adjustable top plates inside the volute are each suspended by four liftable rods; the third adjustable top plate inside the volute is suspended by three liftable rods; and the fourth adjustable top plate inside the volute is suspended by one liftable rod.

[0016] Furthermore, a metal sealing sheet is provided on the side of the adjustable top plate inside the volute, and a metal braided soft sealing sheet is also provided on the side of the top plate located at the flue gas inlet. The metal braided soft sealing sheet is connected to the inner wall of the volute to ensure the flue gas sealing of the top plate during the adjustment process.

[0017] Furthermore, both the outer and inner conical guide vanes are downwardly curved arc-shaped plates, and are evenly distributed along the circumference of the guide cone.

[0018] A drying tower system includes a drying tower body and a rotary atomizer disposed on the drying tower body. The flue gas distributor is installed at the top of the drying tower body, the flue gas outlet faces inward into the tower, and the rotary atomizer is located below the center of the flue gas outlet.

[0019] The operation control method for an adjustable flue gas distributor includes the following steps: Step 1: Monitor the flow rate or velocity of the flue gas entering the flue gas distributor; Step 2: When the flue gas flow rate drops to the corresponding inlet velocity being lower than a preset threshold, the height and angle of the adjustable top plate inside the volute are adjusted by the top plate adjusting electric winch to reduce the flue gas flow area inside the volute and change its convergence angle. Step 3: Simultaneously increase the height of the outer and inner conical guide vanes by synchronously adjusting the electric winch of the inner guide vane.

[0020] Furthermore, the preset threshold flow rate in step 2 is 9 m / s.

[0021] The beneficial effects of this invention are: 1. This solution adjusts the flow area and convergence angle within the flue gas distributor volute by adding four adjustable top plates and corresponding electric adjusting winches inside the volute. Simultaneously, it adjusts the height of the guide vanes and the flow area of ​​the guide channel by adding corresponding electric adjusting winches to the guide vane tie rods inside the guide cone. This adapts to various unit load conditions, further ensuring the flow velocity and flow field of the flue gas within the volute and guide cone. It ensures efficient gas-liquid mixing during the atomization of desulfurization wastewater and optimizes the flow field throughout the drying tower. This guarantees the drying tower's adaptability to various unit loads, meeting the drying requirements for desulfurization wastewater at any time, and ultimately perfectly adapting to the power plant industry's "deep peak shaving" policy.

[0022] 2. Furthermore, this solution can modify the flue gas distributors of existing projects, transforming fixed flue gas distributors into new adjustable flue gas distributors with moving blades. This solves the dilemma that when the boiler unit temperature is too low, the existing drying system can only be shut down and cannot continue to treat desulfurization wastewater; it also reduces the pressure of continuously rising chloride ions in the desulfurization tower that cannot be discharged, ensuring the safe operation of the desulfurization system. Attached Figure Description

[0023] Figure 1 The diagram below shows the overall structure of the adjustable flue gas distributor of the present invention.

[0024] Figure 2 The diagram below shows the layout and structure of the adjustable top plate inside the volute in this invention.

[0025] Figure 3 A is a perspective view of the present invention; List of reference numerals in the attached diagram: 1. Flue gas inlet; 2. Volute; 3. Adjustable top plate inside the volute; 4. Metal sealing sheet; 5. Metal braided soft sealing sheet; 6. Adjustable pull rod for the top plate inside the volute; 7. Electric winch for adjusting the top plate; 8. Guide cone; 9. Outer cone guide vane; 10. Inner cone guide vane; 11. Adjustable pull rod for the inner cone guide vane; 12. Electric winch for the inner cone guide vane; 13. Flue gas outlet; 14. Rotary atomizer; 15. Drying tower body; 16. First part of the adjustable top plate inside the volute; 17. Second part of the adjustable top plate inside the volute; 18. Third part of the adjustable top plate inside the volute; 19. Fourth part of the adjustable top plate inside the volute. Detailed Implementation

[0026] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0027] like Figure 1-3 As shown, the device in this embodiment mainly consists of a volute 2, an adjustable top plate inside the volute 3, a metal sealing sheet 4, a metal braided soft sealing sheet 5, a liftable rod for the top plate inside the volute 6, an electric winch for adjusting the top plate 7, a guide cone 8, an outer cone guide vane 9, an inner cone guide vane 10, a liftable rod for the inner cone guide vane 11, and an electric winch for the inner cone guide vane 12.

[0028] The volute 3 also contains an adjustable top plate 3, which is composed of four independent top plates, namely... Figure 2 The adjustable top plate consists of four parts: a first part 16, a second part 17, a third part 18, and a fourth part 19. The first part 16 has metal sealing plates 4 on both sides, which are welded to a metal braided soft sealing plate 5 at the inlet. The second part 17, the third part 18, and the fourth part 19 also have metal sealing plates 4 on both sides. Both the sealing plates 4 and the metal braided soft sealing plates 5 are used to maintain a sealed flue gas environment during top plate adjustment.

[0029] The first and second adjustable top panels 16 and 17 inside the volute are both suspended inside the volute by four lifting rods 6, each rod having an electric winch 7 for adjusting the top panel. The third adjustable top panel 18 inside the volute is suspended inside the volute by three lifting rods 6, each rod having an electric winch 6 for adjusting the top panel. The fourth adjustable top panel 19 inside the volute is suspended inside the volute by one lifting rod 6, with an electric winch 6 for adjusting the top panel. Each electric winch can adjust the length of the rod connected to it, thereby adjusting the height and angle of each top panel.

[0030] The outer cone guide vane 9 and the inner cone guide vane 10 inside the guide cone are suspended inside the guide cone by four cone inner guide vane lifting rods 11. Each rod has an inner cone guide vane electric winch 12. Each electric winch can adjust the length of the rod connected to it, thereby adjusting the height of the inner and outer cone guide vanes and the inner cone guide vane, further changing the flow area of ​​the inner channel and the outer channel of the guide cone.

[0031] The volute 3 and the guide cone shell 8 are designed according to the working conditions under full load. When the unit is at full load, the flue gas enters from the flue gas inlet 1 of the flue gas distributor. The flow cross section in the volute 2 channel continuously contracts and finally exits from the flue gas outlet 13 of the flue gas distributor. At this time, the cross-sectional area of ​​the flue gas inlet 1, the channel in the volute 2 and the flue gas outlet 13 are the largest, which can accommodate the most flue gas and ensure that the inlet flow velocity is 9~13m / s, forming a high-quality flow field in the tower.

[0032] When the unit load decreases and the flow velocity at the flue gas distributor inlet drops below 9 m / s, the height and angle of each top plate are adjusted by regulating the electric winch 7 of each top plate. This reduces the flue gas flow area and increases the convergence angle of the volute. This ensures that the flue gas velocity in the flue gas distributor is within the optimal velocity range, and that the convergence angle of the volute adapts to the current operating conditions, guaranteeing the flow field and velocity within the volute. Simultaneously, the height of the outer cone guide vane 9 and the inner cone guide vane 10 are increased by synchronously adjusting the electric winch 12 of the inner cone guide vane, reducing the flow area within the guide cone channel. This ensures that the flue gas velocity in the inner channel and at the flue gas outlet is within the optimal velocity range, maintaining the flow field of the flue gas within the tower without reducing the velocity of the flue gas ejected from the inner channel. This ensures that the flue gas curtain maintains good coverage of the droplets ejected from the rotating atomizer, ensuring that the atomized droplets are concentrated in a fixed area within the drying tower, and allowing for better contact and drying between the flue gas and the droplets. After this adjustment, the flue gas flow field inside the drying tower can be better concentrated in a certain range near the center of the tower, and will not spread out rapidly due to the decrease in flue gas volume, causing the tower walls to stick and ash to accumulate.

[0033] Through the above operation and adjustment methods, the drying tower equipped with this new type of adjustable flue gas distributor can adapt to the full operating load of the power plant and perfectly adapt to various flue gas volumes and corresponding wastewater drying volumes.

[0034] Specific implementation methods are described below. like Figure 1 and Figure 2 As shown, the adjustable flue gas distributor of the present invention mainly consists of a volute 2, a guide cone 8, and an adjustment mechanism. The outer shells of the volute 2 and the guide cone 8 are designed for full-load operation. The flue gas passage of the volute 2 is spirally tapered. The guide cone 8 is an inverted cone shape, and its interior is divided into an outer air passage and an inner air passage by a structural partition. An outer cone guide vane 9 is arranged in the outer air passage, and an inner cone guide vane 10 is arranged in the inner air passage. These guide vanes are all downwardly curved arc plates, evenly distributed circumferentially, and their spiral direction is consistent with the flue gas flow direction, used to guide and enhance the swirling flow.

[0035] To ensure sealing, metal sealing plates 4 are installed on both sides of each top plate. A metal braided soft sealing plate 5 is also welded to the side of the first part 16 of the adjustable top plate inside the volute at the flue gas inlet 1 to accommodate displacement during top plate adjustment and prevent flue gas leakage. Inside the guide cone 8, the outer cone guide vane 9 and the inner cone guide vane 10 are suspended by four shared cone guide vane lifting rods 11, with the upper ends of the rods connected to the cone guide vane electric winches 12. By driving the electric winches 12, the height of all guide vanes can be adjusted synchronously, thereby changing the flow area of ​​the inner and outer air passages of the guide cone.

[0036] When the unit load decreases, causing the flow velocity at flue gas inlet 1 to drop below 9 m / s, the control system initiates an adjustment program. By adjusting the electric winch 7 on the top plate, the height and angle of the adjustable top plates 3 within each volute are reduced to varying degrees, reducing the flow area and increasing the taper angle of the volute channel, thus ensuring the flue gas velocity and flow field morphology within the volute. Simultaneously, by adjusting the electric winch 12 on the inner guide vanes, the height of the outer cone guide vanes 9 and the inner cone guide vanes 10 are raised, reducing the channel area within the guide cone. This ensures that the flue gas maintains a sufficient flow velocity at outlet 13, forming a tight flue gas curtain that effectively encapsulates the droplets ejected by the rotating atomizer 14, concentrating them in the central area of ​​the tower for thorough drying, preventing diffusion to the tower wall due to reduced flue gas volume and causing wall adhesion and ash buildup. Through these methods, the flue gas distributor of this invention ensures stable and efficient operation of the drying tower across a full operating range from 100% to 20%, completely solving the problem of untreated desulfurization wastewater during deep peak shaving of the unit.

[0037] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A fully adjustable flue gas distribution device suitable for drying desulfurization wastewater, comprising a volute (2) and a guide cone (8) disposed below the volute (2), wherein a flue gas inlet (1) is provided on the side wall of the volute (2), and a flue gas outlet (13) is formed at the bottom of the guide cone (8); characterized in that: An adjustable top plate (3) is provided on the inner side of the top of the volute (2). A liftable rod (6) is connected above the adjustable top plate (3). The liftable rod (6) extends upward through the top wall of the volute (2) and is connected to the electric winch (7) for adjusting the top plate located outside the volute (2). An outer conical guide vane (9) is provided in the outer air passage of the guide cone (8), and an inner conical guide vane (10) is provided in the inner air passage. A liftable rod (11) for the inner conical guide vane is connected above both the outer conical guide vane (9) and the inner conical guide vane (10).

2. The adjustable flue gas distribution device suitable for desulfurization wastewater drying under all operating conditions as described in claim 1, characterized in that: The adjustable pull rod (11) of the inner guide vane extends upward through the top wall of the guide cone (8) and is connected to the electric winch (12) of the inner guide vane located at the top of the guide cone (8).

3. The adjustable flue gas distribution device suitable for drying desulfurization wastewater under all operating conditions according to claim 1, characterized in that: The adjustable top plate (3) inside the volute is composed of multiple independent top plate sections spliced ​​together.

4. The adjustable flue gas distribution device suitable for drying desulfurization wastewater under all operating conditions according to claim 3, characterized in that: The adjustable top plate (3) inside the volute includes, in sequence from the flue gas inlet (1), a first part (16), a second part (17), a third part (18), and a fourth part (19).

5. The adjustable flue gas distribution device suitable for desulfurization wastewater drying under all operating conditions as described in claim 3, characterized in that: The first part (16) and the second part (17) of the adjustable top plate inside the volute are each suspended by four lifting rods (6).

6. The adjustable flue gas distribution device suitable for drying desulfurization wastewater under all operating conditions according to claim 3, characterized in that: The third part (18) of the adjustable top plate inside the volute is suspended by three lifting rods (6); the fourth part (19) of the adjustable top plate inside the volute is suspended by one lifting rod (6).

7. The adjustable flue gas distribution device suitable for drying desulfurization wastewater under all operating conditions according to claim 1, characterized in that: A metal sealing plate (4) is provided on the side of the adjustable top plate (3) inside the volute.

8. The adjustable flue gas distribution device suitable for drying desulfurization wastewater under all operating conditions according to claim 1, characterized in that: A metal braided soft sealing sheet (5) is also provided on the side of the top plate at the flue gas inlet (1), and the metal braided soft sealing sheet (5) is connected to the inner wall of the volute (2).

9. The adjustable flue gas distribution device suitable for drying desulfurization wastewater under all operating conditions according to claim 1, characterized in that, Both the outer conical guide vane (9) and the inner conical guide vane (10) are downwardly curved arc plates.

10. The adjustable flue gas distribution device suitable for drying desulfurization wastewater under all operating conditions according to claim 1, characterized in that, The outer cone guide vane (9) and the inner cone guide vane (10) are evenly distributed along the circumference of the guide cone (8).

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