Dust removal unit, dust removal module, dust removal device and flue gas purification method

Abstract

The present application relates to the field of energy saving and environmental protection, and discloses a dust removal unit, a dust removal module, a dust removal device and a flue gas purification method, wherein the dust removal unit comprises a bending part with a vertically extending bending line, which can make the horizontal airflow change direction and make the dust particles in the horizontal airflow fall vertically. Through the above technical solution, the flue gas flows to the dust removal unit under the action of pressure, the dust removal unit can make the flow direction of the gas change abruptly, and then separate the flue gas and the contained dust particles by using the momentum difference between the dust particles and the gas. The dust particles separated from the gas body no longer fall along the vertical direction under the influence of the gas flow, flue gas dust removal is achieved, and the dust particles can be collected and treated.

Description

Technical Field

[0001] This invention relates to the field of energy conservation and environmental protection, specifically to a dust removal unit, a dust removal module, a dust removal device, and a flue gas purification method. Background Technology

[0002] The purification of coal-fired flue gas mainly employs selective catalytic reduction (SCR) denitrification. The denitrified flue gas undergoes dust removal via an electrostatic precipitator, followed by wet desulfurization before being discharged. However, the large amount of dust in the coal-fired flue gas can cause frictional damage to the denitrification catalyst and obscure active sites, affecting catalytic lifespan and efficiency. Furthermore, to strictly control NO... X Excessive ammonia injection during emissions is common, and unreacted ammonia gas escapes into downstream processes or the atmosphere along with the denitrification flue gas. This is compounded by water vapor and SO2 emissions. X Under certain conditions, escaped ammonia readily forms ammonium salt byproducts NH4HSO4 and (NH4)2SO4, which then adhere to particulate matter such as fly ash, increasing the generation of small-diameter particulate matter (PM1.0) and forming floating pollutants. This not only leads to excessive emissions of purified gas but also increases the fugitive emissions of gaseous ammonium salts.

[0003] Dust removal devices in coal-fired power plants mainly consist of electrostatic precipitators and bag filters. Excessive ammonia escape leads to the formation of large amounts of ammonium bisulfate. Ammonium bisulfate adheres to fly ash, increasing its stickiness and causing it to adhere to the cathode wires, reducing secondary current and even causing back corona discharge. The acidic ammonium bisulfate also corrodes the needle wires, causing permanent damage to the needle tips. Highly sticky dust also adheres to the filter bags in large quantities, making cleaning difficult and significantly increasing operating resistance. Prolonged cleaning difficulties allow sticky dust to penetrate into the filter bags, causing irreversible blockage. Filter bag blockage increases the filtration velocity, exceeding design limits, potentially causing the filter bags to rupture and fail, making it impossible to meet ultra-low emission standards for flue gas. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of low dust removal efficiency and poor effect in the existing technology, and to provide a dust removal unit, a dust removal module, a dust removal device and a flue gas purification method. The device has high dust removal efficiency.

[0005] To achieve the above objectives, a first aspect of the present invention provides a dust removal unit, including a bent portion having a vertically extending bend line, the bent portion being capable of turning a horizontal airflow and causing dust particles in the horizontal airflow to detach and fall vertically.

[0006] Optionally, it includes an inlet guide plate, an outlet guide plate, and a first dust collection trough, which are arranged at an angle to the inlet guide plate. The first dust collection trough is provided with a dust collection port, and the inlet guide plate and the outlet guide plate are respectively connected to the two sides of the dust collection port in the horizontal direction.

[0007] Optionally, the first dust collection trough has a triangular cross-section and includes a bottom plate and two side plates. The inlet guide plate is smoothly connected to one of the side plates, and the outlet guide plate is connected to the other side plate at an angle.

[0008] Optionally, the included angle between the inlet guide plate and the outlet guide plate is 60 degrees to 120 degrees.

[0009] Optionally, the inlet guide plate and the outlet guide plate are configured as straight plates; or, the inlet guide plate and the outlet guide plate are configured as arc-shaped plates; and / or the first dust collection trough is configured as a triangular trough with a horizontal width that gradually decreases along the direction of the dust collection port; or, the first dust collection trough is configured as a straight trough with a horizontal width that remains unchanged along the direction of the dust collection port.

[0010] A second aspect of the present invention provides a dust removal module, comprising a plurality of dust removal channel layers arranged vertically at intervals, each of the dust removal channel layers comprising dust removal channel sections arranged horizontally at intervals, wherein the dust removal channel section comprises one or an array of any of the dust removal units described above.

[0011] Optionally, multiple dust removal channel layers are arranged at intervals along the height direction to form dust removal channels.

[0012] A third aspect of the present invention provides a dust removal device, comprising a dust collector housing and a dust removal module disposed inside the dust collector housing as described in any one of the above descriptions, wherein the dust collector housing has a flue gas inlet and a flue gas outlet at both ends, and a dust collection outlet is provided at the bottom of the dust collector housing.

[0013] Optionally, it also includes a dust removal mechanism disposed on the top of the dust collector housing, the dust removal mechanism being configured to apply vibration to the dust removal channel section, and / or the dust removal mechanism being configured to inject clean water into the dust removal channel from the top.

[0014] The fourth aspect of the present invention provides a flue gas purification method, which first removes dust from the flue gas through a functional channel dust removal process, then denitrates the flue gas through a selective catalytic reduction denitrification process, and finally desulfurizes the flue gas through a wet desulfurization process. The functional channel dust removal process is implemented by any one of the dust removal devices described above.

[0015] Through the above technical solution, the flue gas flows to the dust removal unit under pressure. The dust removal unit can change the direction of gas flow abruptly, thereby using the momentum difference between dust particles and gas to separate the flue gas from the dust particles it contains. After being separated from the main gas mass, the dust particles no longer fall vertically due to the influence of gas flow, thus achieving dust removal from the flue gas and enabling the agglomeration of dust particles. Attached Figure Description

[0016] Figure 1 This is a top view of one embodiment of the dust removal unit in this invention;

[0017] Figure 2 This is a front view of one embodiment of the dust removal unit in this invention;

[0018] Figure 3 This is a top view of another embodiment of the dust removal unit in this invention;

[0019] Figure 4 This is a schematic diagram of one embodiment of the dust removal device in this invention;

[0020] Figure 5 This is a flowchart illustrating one embodiment of the flue gas purification method of the present invention.

[0021] Explanation of reference numerals in the attached figures

[0022] 1-Inlet guide plate, 2-Outlet guide plate, 3-First dust collection trough, 4-First arc guide plate, 5-Second arc guide plate, 6-Second dust collection trough, 7-Dust removal channel section, 8-Dust collector shell, 9-Dust removal channel, 10-Flue gas inlet, 11-Flue gas outlet, 12-Dust collection outlet, 13-Dust removal mechanism, 14-Functional channel dust removal process, 15-Selective catalytic reduction denitrification process, 16-Wet desulfurization process, 17-Air preheater, 18-First flue gas inflow direction, 19-First flue gas outflow direction, 20-Dust particle discharge outlet, 21-Second flue gas inflow direction, 22-Second flue gas outflow direction, 23-Vertical direction. Detailed Implementation

[0023] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0024] The first aspect of the present invention provides a dust removal unit, including a bent portion having a vertically extending bend line, the bent portion being able to turn the horizontal airflow and cause dust particles in the horizontal airflow to detach and fall vertically.

[0025] like Figure 2As shown, the dust removal unit has three bends, which are connected to form a bend. The flue gas enters the dust removal unit along the extension direction of the inlet guide plate 1, i.e., the first flue gas inflow direction 18. After the flue gas collides with the bend, the gas flow direction changes abruptly. The dust particles in the flue gas rely on their own velocity and weight to form momentum, and collide with the abrupt path, causing them to fall off. The dust particles that have separated from the gas are no longer affected by the gas flow and can move independently. This effectively solves the problem in the traditional method of separating flue gas from its dust particles by using the momentum difference between dust particles and gas. The gas still has a strong influence on the flow of the main gas even after the dust particles have separated from the main gas. This improves the dust removal effect. Furthermore, the dust particles fall and accumulate. The accumulated dust particles are then uniformly processed to avoid the situation in traditional dust removal devices where dust particles adhere to the inside and cause blockage.

[0026] In one embodiment, the dust removal unit includes an inlet guide plate 1, an outlet guide plate 2, and a first dust collection trough 3, which are arranged at an angle. The inlet guide plate 1 and the outlet guide plate 2 are provided with a dust collection port. The inlet guide plate 1 and the outlet guide plate 2 are respectively connected to the two sides of the dust collection port in the horizontal direction.

[0027] Combination Figure 2 and Figure 3 As shown, the first dust collection trough 3 is the bend. The flue gas enters the dust removal unit along the extension direction of the inlet guide plate 1, which is the first flue gas inflow direction 18. When the flue gas flows to the end of the inlet guide plate 1, it will collide with the first dust collection trough 3. Then the flue gas leaves the dust removal unit along the extension direction of the outlet guide plate 2, which is the first flue gas outflow direction 19. When the flue gas enters the first dust collection trough 3, the dust particles in the flue gas have a certain gravity and will collide with the inner wall of the first dust collection trough 3 and lose speed. Then, under the action of gravity, they fall vertically along the inner wall of the first dust collection trough 3 in the direction 23. The bottom of the first dust collection trough 3 is provided with a gradually narrowing dust particle discharge outlet 20, which facilitates the collection and discharge of dust particles.

[0028] Meanwhile, since the internal space of the first dust collection tank 3 is too small compared to the flow space in the dust removal unit, the gas in the flue gas has very little weight and kinetic energy. Since there is gas in the first dust collection tank 3, the flue gas cannot enter the first dust collection tank 3. However, the dust particles can enter the first dust collection tank 3 by relying on their own speed and weight to generate kinetic energy, and then collide and lose speed. Since no gas enters the first dust collection tank 3, the dust particles can fall and accumulate without being disturbed by the gas flow.

[0029] Furthermore, the first dust collection tank 3 includes a bottom plate and two side plates, with the inlet guide plate 1 smoothly connected to one of the side plates and the outlet guide plate 2 connected at an angle to the other side plate.

[0030] like Figure 2 As shown, the inlet guide plate 1 is smoothly connected to the side plate, allowing the flue gas and dust particles in the flue gas to flow smoothly into the first dust collection tank 3. The bottom plate is connected to the two side plates at an angle. The flue gas will flow out along the direction of the side plate, the bottom plate, the side plate, and the outlet guide plate 2. The dust particles in the flue gas lose most of their kinetic energy after colliding with the bottom plate in the first dust collection tank 3, and then collide with the other side plate. After multiple collisions in the first dust collection tank 3, they will completely lose speed and fall vertically under their own gravity, thus capturing the dust particles in the flue gas.

[0031] Furthermore, the included angle between the inlet guide plate 1 and the outlet guide plate 2 is 60 degrees to 120 degrees.

[0032] like Figure 2 As shown, the angle between the inlet guide plate 1 and the outlet guide plate 2 causes a sudden change in gas flow. If the angle is too large, it will not have the effect of causing a sudden change in gas flow; if the angle is too small, the space formed between the inlet guide plate 1 and the outlet guide plate 2 will be too small, resulting in insufficient flue gas flow and thus reduced dust removal efficiency. Therefore, an angle between 60 degrees and 120 degrees is more suitable. In this invention, the angle between the inlet guide plate 1 and the outlet guide plate 2 is set to 90 degrees.

[0033] In one implementation, the inlet guide plate 1 and the outlet guide plate 2 are configured as straight plates; or, the inlet guide plate 1 and the outlet guide plate 2 are configured as arc-shaped plates; and / or the first dust collection groove 3 is configured as a triangular groove with a horizontal width that gradually decreases along the direction of the dust collection port; or, the first dust collection groove 3 is configured as a straight groove with a horizontal width that remains unchanged along the direction of the dust collection port.

[0034] Combination Figure 2 and Figure 3 As shown, the inlet guide plate 1 and the outlet guide plate 2 can be set to any shape, such as a straight plate, an arc plate, a corrugated plate, etc.; the dust collection trough can be set as a triangular trough with a gradually decreasing horizontal width or a straight trough with a constant width. In this application, the inlet guide plate 1 and the outlet guide plate 2 are set as straight plates, and the first dust collection trough 3 is set as a triangular trough with a gradually decreasing horizontal width along the direction of the dust collection port. That is to say, the dust collection port of the first dust collection trough 3 is smaller than its internal cavity, which can effectively block air from entering the first dust collection trough 3. In other words, the first dust collection trough 3 can capture and collect dust particles without affecting the gas in the flue gas. The resistance to the overall flow of the flue gas is very low, which greatly improves the flow speed in the flue gas dust removal process, thereby improving the dust removal efficiency.

[0035] In another embodiment, the dust removal unit includes a first arc guide plate 4, a second arc guide plate 5, and a second dust collection trough 6, all of which are vertically arranged. The first arc guide plate 4 and the second arc guide plate 5 are respectively connected to the two sides of the second dust collection trough 6 in the horizontal direction.

[0036] like Figure 4 As shown, the second dust collection tank 6 is configured as a straight tank structure. The first arc guide plate 4 and the second arc guide plate 5 enable the gas to flow along the arc. The flue gas enters the dust removal unit along the extension direction of the first arc guide plate 4, i.e., the second flue gas inflow direction 21. The dust particles in the flue gas will enter the second dust collection tank 6, collide, and fall off the gas. The gas in the flue gas will flow out of the dust removal unit along the extension direction of the second arc guide plate 5, i.e., the second flue gas outflow direction 22. The second dust collection tank 6 has the same function as the first dust collection tank 3, which can capture dust particles without causing resistance to the gas. The dust particles in the second dust collection tank 6 can fall and accumulate without being disturbed by the gas flow.

[0037] A second aspect of the present invention provides a dust removal module, comprising a plurality of dust removal channel layers arranged vertically at intervals, each dust removal channel layer comprising dust removal channel sections 7 arranged at intervals, each dust removal channel section 7 comprising one or a plurality of dust removal units of the above content arranged in an array.

[0038] like Figure 1 As shown, the dust removal channel section 7 is spliced ​​together at intervals along the first horizontal direction and the second horizontal direction to form a dust removal channel layer (the first horizontal direction is...). Figure 1 The left and right directions, and the second horizontal direction is the direction perpendicular to the paper (the size and number of dust removal channel layers can be set according to actual needs).

[0039] Furthermore, multiple dust removal channel layers are arranged at intervals along the height direction to form dust removal channels 9.

[0040] like Figure 1 As shown, the flue gas enters the dust removal unit through the dust removal channel 9 for dust removal. The dust removal channel 9 is evenly distributed across the cross-section of the flue gas flow and is composed of multiple dust removal units connected in series in the flue gas flow direction. This not only effectively solves the equipment manufacturing problems in large-section uniform dust removal and cascade dust removal, but also significantly reduces the cross-sectional area of ​​the gas entering the same dust removal channel, reduces the interference of gas layers, and greatly improves the dust removal effect.

[0041] A third aspect of the present invention provides a dust removal device, including a dust collector housing 8 and a dust removal module as described above disposed inside the dust collector housing 8. The dust collector housing 8 has a flue gas inlet 10 and a flue gas outlet 11 at both ends, and a dust collection outlet 12 at the bottom.

[0042] like Figure 1 As shown, the dust removal modules are evenly distributed inside the dust collector housing 8 and occupy most of its space, so that the flue gas must be removed by the dust removal modules before flowing to the next position to ensure sufficient dust removal of the flue gas. The dust collector housing 8 is set vertically, and the flue gas inlet 10 and the flue gas outlet 11 extend along the first horizontal direction. The flue gas flows into the dust collector through the flue gas inlet 10 and is removed by the dust removal modules. Then it flows to the next process through the flue gas outlet 11. The dust particles in the first dust collection tank 3 and the second dust collection tank 6 will fall to the bottom of the dust collector housing 8 under the action of gravity. The lower part of the dust collector housing 8 is set in a tapered shape, and a dust collection outlet 12 is set at its bottom, which can uniformly process the filtered dust particles.

[0043] In one embodiment, the dust removal device also includes a dust removal mechanism 13 disposed on the top of the dust collector housing 8. The dust removal mechanism 13 is configured to apply vibration to the dust removal channel section 7, and / or the dust removal mechanism 13 is configured to inject clean water into the dust removal channel 9 from the top.

[0044] like Figure 1 As shown, the dust removal mechanism 13 can be connected to the dust removal module. In the first embodiment, the dust removal mechanism 13 can be cleaned by vibration. By vibrating the dust removal module, the dust particles attached to the inner wall of the dust removal unit are shaken off to achieve the dust removal effect. In the second embodiment, the dust removal mechanism 13 can be cleaned by water injection. By setting multiple nozzles above the dust removal module, water is injected into the dust removal channel 9, so that the dust particles on the inner wall of the dust removal channel flow with the water to the bottom and are discharged.

[0045] The fourth aspect of the present invention provides a flue gas purification method, which first removes dust from the flue gas through a functional channel dust removal process 14, then removes nitrogen from the flue gas through a selective catalytic reduction denitrification process 15, and finally desulfurizes the flue gas through a wet desulfurization process 16. The functional channel dust removal process 14 is implemented by the dust removal device mentioned above.

[0046] like Figure 5 As shown, the flue gas first enters the functional channel dust removal process 14 for dust removal. After removing most of the dust, it enters the selective catalytic reduction denitrification process 15, where it undergoes denitrification with the supplied ammonia under the action of a denitrification catalyst (not shown in the figure). After removing the nitrogen oxides contained in the flue gas, the flue gas enters the air preheater 17 to exchange heat with the air and cool down before being sent to the wet desulfurization process 16. After removing SO2, it is discharged into the atmosphere as emission flue gas, thus completing the purification of coal-fired flue gas.

[0047] The coal-fired flue gas is uniformly distributed across the cross-section of the flue gas flow by the functional channel dust removal process 14 and dust removal channel 9 set before the selective catalytic reduction denitrification process 15. The dust removal device, which is composed of multiple dust removal functional channel sections connected in series in the flue gas flow direction, achieves 96% dust removal within a gas resistance pressure drop of less than 250Pa. This significantly reduces the erosion and wear of the denitrification catalyst, improves the utilization rate of catalyst active sites, and thus improves the denitrification efficiency.

[0048] As an alternative implementation, the flue gas can first undergo selective catalytic reduction (SCR) denitrification process 15 for denitrification, then undergo wet desulfurization process 16 for desulfurization, and finally enter the functional channel dust removal process 14 for dust removal before being discharged into the atmosphere. When the functional channel dust removal process is set after wet desulfurization, the dust removal efficiency is greater than 99%, and the airflow resistance of the functional channel dust removal process is less than 150 Pa.

[0049] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0050] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0051] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A dust removal unit, characterized in that, The device includes an upright inlet guide plate (1), an upright outlet guide plate (2), and an upright first dust collection trough (3). The inlet guide plate (1) and the outlet guide plate (2) are arranged at an angle. The first dust collection trough (3) is a bent section with a vertically extending bend line. The bend section can turn the horizontal airflow and cause the dust particles in the horizontal airflow to detach and fall vertically. The first dust collection trough (3) is provided with a dust collection port. The inlet guide plate (1) and the outlet guide plate (2) are respectively connected to the two sides of the horizontal direction of the dust collection port. The first dust collection trough (3) includes a bottom plate and two side plates. The inlet guide plate (1) is smoothly connected to one of the side plates, and the outlet guide plate (2) is connected at an angle to the other side plate.

2. The dust removal unit according to claim 1, characterized in that, The included angle between the inlet guide plate (1) and the outlet guide plate (2) is 60 degrees to 120 degrees.

3. The dust removal unit according to claim 1, characterized in that, The inlet guide plate (1) and the outlet guide plate (2) are configured as straight plates; or, the inlet guide plate (1) and the outlet guide plate (2) are configured as curved plates; and / or The first dust collection groove (3) is configured as a triangular groove with a horizontal width that gradually decreases along the direction of the dust collection port; or, the first dust collection groove (3) is configured as a straight groove with a horizontal width that remains unchanged along the direction of the dust collection port.

4. A dust removal module, characterized in that, It includes a plurality of vertically spaced dust removal channel layers, each of the dust removal channel layers including horizontally spaced dust removal channel sections (7), each dust removal channel section (7) including one or a plurality of dust removal units as described in any one of claims 1-3 arranged in an array.

5. The dust removal module according to claim 4, characterized in that, Multiple dust removal channel layers are arranged at intervals along the height direction to form dust removal channels (9).

6. A dust removal device, characterized in that, The dust collector includes a dust collector housing (8) and a dust collection module as described in any one of claims 4-5 disposed inside the dust collector housing (8). The dust collector housing (8) has a flue gas inlet (10) and a flue gas outlet (11) at its two ends in the horizontal direction, and a dust collection outlet (12) at the bottom of the dust collector housing (8).

7. The dust removal device according to claim 6, characterized in that, It also includes a dust removal mechanism (13) disposed on the top of the dust collector housing (8), the dust removal mechanism (13) being configured to apply vibration to the dust removal channel section (7), and / or the dust removal mechanism (13) being configured to inject clean water into the dust removal channel (9) from the top.

8. A method for purifying flue gas, characterized in that, First, the flue gas is dusted through a functional channel dust removal process (14), then the flue gas is denitrated through a selective catalytic reduction denitrification process (15), and finally the flue gas is desulfurized through a wet desulfurization process (16). The functional channel dust removal process (14) is implemented by the dust removal device described in any one of claims 6-7.

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