A dust capturing and purifying device for cement kiln head exhaust gas

Abstract

The application relates to a dust capturing and purifying device for cement kiln head waste gas, and belongs to the technical field of industrial flue gas dust removal and environmental protection. The device comprises a shell, a discharge electrode assembly and a dust collecting electrode assembly arranged in the shell, and a vibration and dust removal assembly. The dust collecting electrode system comprises a plurality of parallel arranged dust collecting electrode plates. The surface of the dust collecting electrode plate is provided with a plurality of longitudinal through flow guide grooves at intervals along the airflow direction. An array of micro pits is arranged on the plate surface between the adjacent two flow guide grooves. The array of micro pits is used for capturing dust. The depth of the flow guide groove is greater than the depth of the micro pit. When the dust in the micro pit is separated by the vibration force, the dust can flow into the flow guide groove on the downstream side of the electrode plate surface along the airflow direction and settle. The application can avoid the occurrence of secondary dust raising as much as possible, and improves the dust removal efficiency and benefit of the device.

Description

Technical Field

[0001] This application relates to the field of industrial flue gas dust removal and environmental protection technology, and in particular to a dust collection and purification device for cement kiln head exhaust gas. Background Technology

[0002] In the cement production process, the exhaust gas discharged from the rotary kiln head (grate cooler) has a huge volume and high temperature, and contains a large amount of high-hardness clinker dust. In order to meet the increasingly stringent air pollutant emission standards, electrostatic precipitators have always been the mainstream or important pretreatment equipment for cement kiln head dust removal due to their large air volume handling capacity, high temperature resistance, low resistance and relatively low operation and maintenance costs.

[0003] Traditional dry plate electrostatic precipitators mainly consist of discharge electrodes (cathode wires) and collecting electrodes (anode plates). Their working principle involves using a high-voltage electric field to ionize the gas. After the dust particles become charged, they move towards the collecting electrode and deposit under the influence of the electric field. To remove the dust layer accumulated on the anode plate surface, current technology generally employs a mechanical rapping device. When the dust accumulates to a certain thickness, a rapping hammer strikes the anvil of the anode array. The resulting mechanical shock wave and acceleration cause the electrode plates to vibrate at high frequency, thereby breaking the adhesion between the dust and the electrode plates, causing the dust layer to peel off and fall into the ash hopper below.

[0004] However, in actual operation, especially for specific working conditions such as clinker dust at the cement kiln head, the traditional mechanical vibration dust removal method still causes secondary dust generation. Summary of the Invention

[0005] The purpose of this application is to provide a dust collection and purification device for cement kiln head exhaust gas, which can minimize the occurrence of secondary dust generation and improve the dust removal efficiency and effect of the device.

[0006] The dust collection and purification device for cement kiln head exhaust gas provided in this application adopts the following technical solution: The invention includes a housing, a discharge electrode assembly and a dust collection electrode assembly disposed within the housing, and a rapping dust removal assembly. The dust collection electrode system comprises several parallel-arranged dust collection electrode plates. The surface of each dust collection electrode plate is provided with several longitudinally penetrating guide grooves spaced apart along the airflow direction. A micro-pit array is provided on the plate surface between two adjacent guide grooves. The micro-pit array is used to capture dust. The depth of the guide grooves is greater than the depth of the micro-pits. When dust in the micro-pits is detached by the rapping force, it can flow along the electrode plate surface in the direction of airflow into the guide groove located downstream of it and settle.

[0007] Optionally, the micro-pit is an asymmetrical spoon-shaped structure, which includes a blocking edge on the upstream side of the airflow and a guide slope on the downstream side of the airflow. The blocking edge is used to force the horizontal airflow to separate and pass over the opening of the micro-pit, and the guide slope extends downward along the surface of the electrode plate and points to an adjacent guide groove on the downstream side of the airflow in the micro-pit.

[0008] Optionally, the width of the guide groove is smaller than the opening diameter of the micro-pit.

[0009] Optionally, the cross-section of the flow channel is Ω-shaped, and the bottom of the flow channel is provided with a fluttering film assembly for improving the flowability of dust.

[0010] Optionally, the flutter film assembly includes a high-temperature resistant metal film strip, which is suspended at the bottom opening of the guide channel.

[0011] Optionally, the inner surface of the micro-pits is provided with a hydrophobic and oleophobic coating.

[0012] Optionally, the rapping cleaning assembly is configured to generate lateral shear vibrations perpendicular to the extension direction of the guide channel to facilitate the lateral sliding of dust from the micro-dimples into the guide channel.

[0013] In summary, this application includes at least one of the following beneficial technical effects: 1. This invention sets up a micro-pit array and a flow channel on the surface of the dust collecting electrode plate. When dust passes over the surface of the dust collecting electrode plate, the surface of the dust collecting electrode plate will adsorb dust, and at the same time, dust will also be attached to the micro-pits. The micro-pits utilize the vortex effect of the fluid boundary layer to lock the dust under the scouring of strong airflow, while the relatively deep flow channel provides a relatively stable environment. It completely isolates the dust collection area and the settling area from the physical structure. When the dust is rapped and cleaned, the dust is quickly drawn into the flow channel after being peeled off from the micro-pits. Since the environment inside the flow channel is relatively stable and there is less gas flow inside, the dust can settle in the flow channel with a relatively stable ambient temperature, thereby effectively avoiding the secondary dust phenomenon caused by the airflow scouring during the rapping moment of traditional flat electrode. 2. By adopting a spoon-shaped micro-pit structure and an Ω-shaped guide channel, the obstruction above the spoon-shaped micro-pit uses the inertia of the high-speed airflow to force boundary layer separation. The high-speed airflow jumps over the opening of the micro-pit, thus forming a stable low-speed zone within the micro-pit, effectively locking in dust and minimizing the probability of the airflow carrying dust out of the micro-pit. The guide slope located downstream and below the airflow facilitates the flow of dust from the micro-pit into the guide channel. After leaving the micro-pit, the dust does not fall vertically over a long distance, but slides laterally along the relatively shortest path into the adjacent guide channel. This structure minimizes the exposure time of dust on the open surface, reducing the risk of re-entry into the airflow and further reducing the probability of secondary dust generation. 3. After prolonged operation, dust accumulating inside the flow channel is prone to occur. This invention suspends a metal film strip at the bottom of the channel. Under the same low-frequency mechanical vibration excitation, due to the small mass and rigidity of the metal film strip, it can generate high-frequency, low-amplitude vibration. This high-frequency vibration breaks the accumulated dust into small pieces or particles, thereby enabling the dust to settle smoothly in the flow channel. 4. The lateral shearing vibration mode configured in this invention provides shear vibration perpendicular to the extension direction of the guide channel to the dust removal plate. It can provide the dust in the spoon-shaped micro-pit with the maximum lateral inertial component pointing towards the guide channel. The lateral force and the guiding slope of the pit work together to relatively efficiently throw the dust directly into the guide channel, thereby further accelerating the speed at which the dust enters the guide channel and further improving the dust removal efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 This is a schematic diagram of the internal structure of the shell in an embodiment of this application; Figure 3 yes Figure 2 Enlarged structural diagram at point A; Figure 4 This is a schematic diagram of the structure of the dust collection electrode assembly in the embodiments of this application; Figure 5 yes Figure 4 Enlarged structural diagram at point B; Figure 6 yes Figure 5 Enlarged structural diagram at point D; Figure 7 yes Figure 4 Enlarged structural diagram at point C; In the diagram, 1 is the casing; 11 is the smoke inlet; 12 is the air outlet; 13 is the collection funnel; 2 is the discharge electrode assembly; 3 is the dust collection electrode assembly; 31 is the dust collection electrode plate; 311 is the micro-pit; 312 is the blocking edge; 313 is the guide slope; 314 is the guide groove; 4 is the fluttering film assembly; 41 is the metal film strip; 5 is the rapping cleaning assembly; 51 is the connecting rod; 52 is the drive rod; 53 is the connecting block; 54 is the rapping block; and 55 is the drive motor. Detailed Implementation

[0015] The following is in conjunction with the appendix Figure 1-7 This application will be described in further detail below.

[0016] A dust collection and purification device for cement kiln head exhaust gas, referring to Figures 1-7 It includes a housing 1, a discharge electrode assembly 2 and a dust collection electrode assembly 3 disposed within the housing 1, and a rapping dust removal assembly 5.

[0017] In this embodiment, a support is provided below the housing 1 to support the entire device. A smoke inlet 11 is provided on one side of the housing 1, and an air outlet 12 is provided on the side of the housing 1 opposite to the smoke inlet 11. Multiple dust collection funnels 13 are arranged below the housing 1 for discharging dust.

[0018] Reference Figure 1 , Figure 2 and Figure 3In this embodiment, the dust collection electrode assembly 3 includes several parallel-arranged dust collection electrode plates 31. All dust collection electrode plates 31 are located inside the housing 1 and are arranged in an array perpendicular to the flue gas flow direction. A channel for flue gas flow is provided between adjacent dust collection electrode plates 31. All dust collection electrode plates 31 are suspended on the inner wall of the top of the housing 1 and are located directly above the collection funnel 13. In this embodiment, the discharge electrode assembly 2 is a spiral electrode column. Multiple electrode columns are also provided in this embodiment, arranged in an array between adjacent dust collection electrode plates 31. The electrode columns do not contact the dust collection electrode plates 31. The multiple electrode columns are arranged vertically and are fixedly installed on the inner wall of the top of the housing 1. A power supply assembly (not shown in the figure) is also provided inside the housing 1. The positive electrode is electrically connected to multiple dust collecting plates 31, and the negative electrode of the power supply component is electrically connected to multiple electrode posts. Thus, the dust collecting plates 31 are positively charged, and the electrode posts are also positively charged. A rapping and cleaning component 5 for tapping the dust collecting plates 31 is also provided on one side of the dust collecting plates 31. When the flue gas flows through the channel between two adjacent dust collecting plates 31, the dust in the flue gas also becomes negatively charged due to absorbing the negative charge on the electrode posts. The positive and negative charges attract each other, so the negatively charged dust will be adsorbed on the dust collecting plates 31. Then, when the rapping and cleaning component 5 taps the dust collecting plates 31, the dust collecting plates 31 will vibrate, thereby shaking off some of the dust adsorbed on the dust collecting plates 31. Then, the shaken-off dust falls into the mobile phone funnel due to gravity, thus realizing the dust collection and purification treatment in the flue gas (this is existing technology and will not be described in detail here).

[0019] Reference Figure 4 , Figure 5 and Figure 6 In this embodiment, the dust collecting electrode plate 31 has an array of micro-pits 311 for collecting dust on the end face of the electrode post, and the end face of the dust collecting electrode plate 31 also has longitudinally arranged guide grooves 314.

[0020] In this embodiment, the guide groove 314 penetrates the bottom of the dust collecting plate 31. The depth of the guide groove 314 is much greater than the depth of the micro-pits 311. In this embodiment, multiple guide grooves 314 are provided, and the multiple guide grooves 314 are evenly spaced along the length direction of the dust collecting plate 31. Several micro-pits 311 are arrayed between two adjacent guide grooves 314. In this embodiment, the micro-pits 311 are configured as a spoon-shaped structure from the upstream side of the airflow to the downstream side of the airflow. In this embodiment, the spoon-shaped structure includes a blocking edge 312 located on the upstream side of the airflow and a guide slope 313 located on the downstream side of the airflow. In this embodiment, the guide slope 313 extends along the surface of the dust collecting plate 31, and in this embodiment, the guide slope 313 is inclined downward along the direction closest to the guide groove 314 located on the downstream side of the airflow.

[0021] When it is necessary to collect and purify the dust in the exhaust gas generated by the cement kiln head, the exhaust gas generated by the cement kiln head is introduced into the flue gas inlet 11 of the shell 1 through an external pipe. Then, when the flue gas flows through the channel between two adjacent dust collecting plates 31, the dust particles in the flue gas absorb the negative charge released by the electrode column, so the dust particles also carry a negative charge. Since the dust collecting plates 31 contain positive charges, the dust with negative charges will move in the direction close to the dust collecting plates 31 until the dust particles are adsorbed on the surface of the dust collecting plates 31. In this embodiment, the surface of the dust collecting plates 31 is provided with several micro-pits 311, which greatly increases the adsorption area of ​​the dust collecting plates 31, thereby greatly improving the dust removal effect of this device in the flue gas.

[0022] Furthermore, the surface of a traditional dust collecting plate 31 lacks pits. Therefore, when flue gas blows across the flat surface of the dust collecting plate 31, the dust already adhering to its surface is easily blown away and detached. This detached dust then re-enters the flowing flue gas, causing secondary dust re-entrainment. In contrast, the dust collecting plate 31 in this embodiment has an array of micro-pits 311 on its surface. When flue gas blows across the surface of the dust collecting plate 31 in this embodiment, because the inner wall of the obstruction edge 312 near the micro-pits 311 is almost perpendicular to the surface of the dust collecting plate 31, when the high-speed flue gas flows along the surface of the dust collecting plate 31, the micro-pits 311 are almost 90 degrees downward relative to the flue gas due to the obstruction edge 312. Since the flue gas has forward inertial momentum, the flue gas... The airflow does not enter the micro-pit 311, but flies directly over it. This airflow passing directly over the micro-pit 311 is called the free shear layer. When the free shear layer passes over the micro-pit 311, it causes the air inside the micro-pit 311 to rotate due to friction between gas molecules. Therefore, a continuously rotating micro-cyclone is formed inside the micro-pit 311, which we call a vortex. This vortex is locked inside the micro-pit 311 and cannot escape. Although the gas inside the pit is rotating, the airflow velocity at the bottom of the pit is relatively slow, or even non-existent. Therefore, when dust particles enter the micro-pit 311, they are drawn to the bottom of the micro-pit 311 by the vortex. Thus, the external flue gas has difficulty carrying the dust from the bottom of the micro-pit 311 out, thereby avoiding secondary dust generation.

[0023] When the rapping and dust removal assembly 5 taps the dust collecting plate 31, the dust in the micro-pits 311 on the dust collecting plate 31 will move out of the micro-pits 311 due to vibration. Due to the effect of the free shear layer, the dust in the micro-pits 311 is still difficult to slide out. Then, in this embodiment, the micro-pits 311 also includes a guide slope 313 located on the downstream side of the airflow. The guide slope 313 can be regarded as a notch in the micro-pits 311. When the dust in the micro-pits 311 slides to the guide slope 313 due to shaking, the guide slope 313 is close to the airflow. The downstream guide channel 314 is inclined downwards, so the dust located in the guide slope 313 will slide into the guide channel 314 under the action of gravity, and then settle into the collection funnel 13 through the guide channel 314. In this embodiment, the depth of the guide channel 314 is much greater than the depth of the micro-pit 311, so the gas inside the guide channel 314 is relatively still. When the dust flows from the guide slope 313 into the guide channel 314, the dust can settle stably into the collection funnel 13 under the action of gravity. 3. In traditional technology, dust falls freely along the smooth outer wall of the electrode plate and settles, but the dust is still exposed to flue gas with a relatively high flow rate. The dust is easily swept away, causing secondary dust. However, the guide channel 314 in this embodiment provides a gas relative temperature environment for dust settling, which greatly reduces the probability that the dust in the settling process will be re-raised by the flue gas, thereby greatly reducing the probability of secondary dust in this device. At the same time, the guide slope in this embodiment is inclined downward along the direction closest to the guide channel 314 on the downstream side of the airflow. Therefore, the dust in the guide slope 313 is not only affected by the gravity vector, but also by the thrust vector of the gas flow due to the angle between the guide slope 313 and the flow direction of the flue gas, which is in the downstream direction. Under the dual action of gravity and wind force, the dust in the guide slope 313 can fall into the guide channel 314 relatively quickly, thereby reducing the time that the dust in the settling state is exposed to the high-speed airflow environment, and further reducing the probability of secondary dust.

[0024] Among them, reference Figure 5In this embodiment, the cross-section of the guide channel 314 is Ω-shaped, and the opening width of the guide channel 314 is smaller than the opening diameter of the micro-pit 311. The Ω-shaped design of the guide channel 314 results in a smaller opening area, making it difficult for high-speed airflow to enter the interior of the guide channel 314 through the opening. This further ensures the stability of the gas inside the guide channel 314, thereby ensuring stable dust settling within the guide channel 314 and further preventing secondary dust generation. Furthermore, the Ω-shaped design of the guide channel 314 maximizes the internal space of the guide channel 314. The larger the internal space, the less likely dust is to accumulate and clog inside the guide channel 314, thus ensuring normal dust settling within the guide channel 314.

[0025] Additionally, refer to Figure 7 In this embodiment, the bottom of the flow channel 314 is provided with a fluttering film assembly 4 for improving dust flowability. The fluttering film assembly 4 in this embodiment includes a high-temperature resistant metal film strip 41. The metal film strip 41 in this embodiment is made of S310 stainless steel, which has good elasticity. The length of the metal film strip 41 in this embodiment is longer than the longest diameter of the cross-section of the flow channel 314. The two ends of the metal film strip 41 are respectively fixedly installed in the channel wall of the flow channel 314, and the middle part of the metal film strip 41 is too long and hangs naturally under the action of gravity.

[0026] After prolonged operation, dust may clump inside the flow channel 314. In this embodiment, a metal film strip 41 is suspended at the bottom of the flow channel 314. Therefore, when the rapping dust removal component 5 strikes the dust collecting plate 31, the vibration wave inside the dust collecting plate 31 is also transmitted to the metal film strip 41. Since the metal film strip 41 has a small mass and rigidity, it can generate high-frequency, low-amplitude vibration. This high-frequency vibration breaks the clump of dust inside the flow channel 314 into small pieces or particles, thereby allowing the dust to settle smoothly inside the flow channel 314.

[0027] In addition, in this embodiment, the inner surface of the micro-pit 311 and the wall of the guide channel 314 are provided with a hydrophobic and oleophobic coating. The coating in this embodiment is polytetrafluoroethylene, which has strong hydrophobicity and oleophobicity. Therefore, even if the dust particles are adhered with water or oil, the dust can slide normally from the micro-pit 311 into the guide channel 314 and settle normally in the guide channel 314.

[0028] Reference Figure 4 and Figure 7 In this embodiment, the rapping and dust removal assembly 5 includes a connecting rod 51, a driving rod 52, a connecting block 53, a rapping block 54, and a driving motor 55.

[0029] In this embodiment, the connecting rod 51 is located on the side of multiple dust collecting plates 31. The connecting rod 51 is arranged in a direction perpendicular to the dust collecting plates 31, and the connecting rod 51 is fixedly connected to the side wall of all dust collecting plates 31. The driving rod 52 is arranged parallel to the connecting rod 51. Both ends of the driving rod 52 are rotatably connected to the inner wall of the housing 1. The driving motor 55 is fixedly installed on the housing 1, and the output shaft of the driving motor 55 is coaxially fixedly connected to the driving rod 52. In this embodiment, multiple connecting blocks 53 and multiple vibrating blocks 54 are provided. The multiple connecting blocks 53 and multiple vibrating blocks 54 correspond one-to-one. One end of the connecting block 53 is fixedly connected to the outer peripheral wall of the driving rod 52, and the vibrating block 54 is hinged to the end of the connecting block 53 away from the driving rod 52.

[0030] When the equipment is started, the drive motor 55 also starts, driving the drive rod 52 to rotate. When the drive rod 52 drives the connecting block 53 and the vibrating block 54 to move upward, the vibrating block 54 does not contact the connecting rod 51. When the vibrating block 54 moves to the highest point, as the drive rod 52 continues to rotate, the vibrating block rapidly descends due to gravity and rotates relative to the connecting block 53. During the rapid descent, the vibrating block will collide with the connecting rod 51. Since the connecting rod 51 is connected to all the dust collecting plates 31, the collision of the vibrating block will cause all the dust collecting plates 31 to vibrate. Then, as the drive rod 52 continues to rotate, the vibrating block 54 rotates and folds with the connecting block 53, so that the vibrating block 54 slides over the connecting rod 51. This cycle is repeated, thereby realizing the periodic tapping of the dust collecting plates 31, and thus realizing the periodic vibration of the dust collecting plates 31.

[0031] In this embodiment, the connecting rod 51 is set on the side wall of the dust collecting plate 31. Therefore, when the vibrating block 54 strikes the connecting rod 51, the vibration direction of all the dust collecting plates 31 is the same as the flue gas flow direction. Thus, this vibration direction can provide the dust in the spoon-shaped micro-pit 311 with the maximum lateral inertial component pointing towards the guide groove 314. Moreover, this lateral force is highly coincident with the extension direction of the guide slope 313 degrees of the pit, which can relatively efficiently throw the dust directly into the guide groove 314, thereby further accelerating the speed at which the dust enters the guide groove 314 and further improving the dust removal efficiency.

[0032] The implementation principle of a dust collection and purification device for cement kiln head exhaust gas in this embodiment is as follows: When dust-laden exhaust gas enters the interior of the shell 1 from the flue gas inlet 11 and passes through two adjacent dust collection plates 31, the obstruction edge 312 upstream of the gas flow in the spoon-shaped micro-pit 311 forces the airflow boundary layer to separate and jump over the opening of the micro-pit 311, forming a closed low-speed vortex within the micro-pit 311, which firmly locks the dust inside the pit bottom; during dust removal, lateral shearing vibration imparts lateral inertial force to the dust, causing it to move along the micro-pit 311. The dust particles slide out from the guide slope 313 located downstream of the airflow and, under the combined external force of gravity and airflow thrust, slide into the Ω-shaped guide trough 314 located closest to the downstream of the airflow in a relatively short time. After entering the guide trough 314, the dust falls onto the suspended metal film strip 41 at the bottom of the trough. The film is excited by low-frequency vibration to generate high-frequency vibration, which causes the dust to be quickly discharged into the collection funnel 13. The whole process avoids the dust returning to the high-speed flowing flue gas, thereby improving the dust capture and collection effect of this device in the flue gas.

[0033] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A dust collection and purification device for cement kiln head exhaust gas, comprising a housing (1), a discharge electrode assembly (2) and a dust collection electrode assembly (3) disposed within the housing (1), and a rapping cleaning assembly (5), characterized in that, The dust collection electrode assembly (3) includes several parallel dust collection electrode plates (31). The surface of the dust collection electrode plate (31) is provided with several longitudinally penetrating guide grooves (314) at intervals along the airflow direction. A micro-pit array (311) is provided on the plate surface between two adjacent guide grooves (314). The micro-pit array (311) is used to capture dust. The depth of the guide groove (314) is greater than the depth of the micro-pit (311). When the dust in the micro-pit (311) is detached by the vibration force, it can flow along the surface of the electrode plate and into the guide groove (314) located downstream of it and settle. The micro-pit (311) is an asymmetrical spoon-shaped structure, which includes a blocking edge (312) on the upstream side of the airflow and a guide slope (313) on the downstream side of the airflow. The blocking edge (312) is used to force the horizontal airflow to separate and pass over the opening of the micro-pit (311). The guide slope (313) extends downward along the surface of the electrode plate and points to the adjacent guide groove (314) on the downstream side of the airflow of the micro-pit (311). The rapping cleaning assembly (5) is configured to generate lateral shear vibrations perpendicular to the extension direction of the guide channel (314) to facilitate the lateral sliding of dust from the micro-pits (311) to the guide channel (314).

2. The dust collection and purification device for cement kiln head exhaust gas according to claim 1, characterized in that, The width of the guide groove (314) is smaller than the opening diameter of the micro-dimple (311).

3. The dust collection and purification device for cement kiln head exhaust gas according to claim 1, characterized in that, The cross-section of the guide channel (314) is Ω-shaped, and the bottom of the guide channel (314) is provided with a flutter film assembly (4) for improving the flowability of dust.

4. The dust collection and purification device for cement kiln head exhaust gas according to claim 3, characterized in that, The flutter film assembly (4) includes a high-temperature resistant metal film strip (41), which is suspended at the bottom opening of the guide channel (314).

5. The dust collection and purification device for cement kiln head exhaust gas according to claim 1, characterized in that, The inner surface of the micro-pit (311) is provided with a hydrophobic and oleophobic coating; The rapping cleaning assembly (5) is configured to generate lateral shear vibrations perpendicular to the extension direction of the guide channel (314) to facilitate the lateral sliding of dust from the micro-pits (311) to the guide channel (314).

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