Bag type filter for tail gas of rotary kiln

Abstract

The invention discloses a bag filter for tail gas of a rotary kiln, the bag filter comprises a cylinder, a filter bag and a conical hopper, the bottom of the conical hopper is connected with a gas inlet and dust discharge assembly, the gas inlet and dust discharge assembly comprises a header pipe communicated with the conical hopper, the header pipe extends into a kiln cover, and one end of the header pipe positioned in the kiln cover is communicated with a diversion branch pipe; rectifying plates are obliquely arranged at the connecting parts of the header pipe and the diversion branch pipes. According to the bag type filter, the air inlet dust discharging assembly is arranged between the conical hopper and the kiln cover, the filter is directly communicated with the kiln cover under the combined action of the main pipe, the rectifying plate and the flow guide branch pipe, the distance between the bag type filter and a rotary kiln can be avoided, part of components in tail gas can be prevented from being condensed into liquid, and blockage of an inlet pipeline and a filter bag is avoided; the negative pressure occurs in the inlet pipeline and the filter, and the filter cleans dust to cause the abnormal phenomenon that the pressure pulsation amplitude in the kiln cover is large, so that the output rate, safety and reliability of equipment can be improved, and the life cycle cost of the equipment is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of filtration and relates to a bag filter for rotary kiln tail gas. Background Art

[0002] The rotary kiln is a thermal equipment widely used in building materials, metallurgy, chemical industry, environmental protection and other industries. During the operation of the rotary kiln, a large amount of dust will be generated due to the chemical reactions such as material crushing, friction, pyrolysis, combustion, air flow carrying and physical state changes. These dusts not only affect the working environment, but also may pollute the atmosphere. Therefore, it is necessary to effectively purify the exhaust gas discharged from the rotary kiln. Traditional dust removal technologies mainly include mechanical dust removal, filtration dust removal, electrostatic dust removal, spray dust removal, etc. Among them, filtration dust removal is more widely used in rotary kiln exhaust gas treatment.

[0003] In the prior art, the bag filter for rotary kiln exhaust gas purification is usually set separately from the rotary kiln, and a long connecting pipe is provided between the rotary kiln and the bag filter. In the process of exhaust gas flowing through the pipe, due to the difference between the exhaust gas temperature and the ambient temperature, the heat in the exhaust gas is continuously dissipated to the outside, resulting in a large decrease in the exhaust gas temperature. When the actual pressure of the exhaust gas exceeds the saturated vapor pressure of certain components, and / or the actual temperature of the exhaust gas drops to the dew point temperature of certain components, some components in the exhaust gas will begin to condense into liquid, and the dust and the condensate are mixed to form a viscous or paste-like substance and adhere to the surface of the pipe and the filter bag. It is difficult or even impossible for the exhaust gas to flow through the pipe and the filter, which seriously affects the production. At the same time, the induced draft fan connected to the outlet of the bag filter continuously draws air, which will cause a high negative pressure in the bag filter and its inlet pipe, and the air will leak in from the sealing defects of the inlet pipe or the bag filter. If the content of combustible components in the exhaust gas reaches the lower explosion limit, an explosion accident will occur. In addition, during pulse jet dust cleaning or reverse airflow dust cleaning, pressure pulsation will occur in the dust discharge pipe of the bag filter, and thus the pressure in the rotary kiln hood will also pulsate. In industrial production equipment, the operating frequency of the variable frequency motor of the exhaust fan (as well as the air volume and pressure of the exhaust fan) is linked to the pressure in the kiln hood. In some industrial equipment (such as oily sludge thermal cracking treatment equipment), some components in the rotary kiln tail gas need to be recycled (for example, the non-condensable gas in the oily sludge thermal cracking treatment tail gas is often used as fuel for hot blast furnaces or boilers). The pressure pulsation in the kiln hood will affect the operating stability and safety of subsequent tail gas recovery equipment (for example, hot blast furnaces or boilers are turned off, combustion is unstable, and heating is unstable, etc.). Therefore, how to effectively avoid abnormal phenomena such as condensation of some components in the tail gas into liquid, negative pressure in the inlet pipe and filter, and large pressure pulsation amplitude in the kiln hood caused by filter dust cleaning is of great significance to improving the operating stability, safety, and service life of the rotary kiln. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a bag filter for rotary kiln exhaust gas, which can avoid the bag filter being far away from the rotary kiln, prevent some components in the exhaust gas from condensing into liquid, reduce the blockage of the inlet pipe and filter bag, the negative pressure inside the inlet pipe and the filter, and the large pressure pulsation amplitude in the kiln cover caused by filter dust cleaning. It can improve the equipment output rate, safety, reliability, and reduce the equipment life cycle cost.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A bag filter for rotary kiln tail gas comprises a cylinder, a filter bag is arranged in the cylinder, a cone bucket is connected to the bottom of the cylinder, an air intake dust removal assembly is connected to the bottom of the cone bucket, the air intake dust removal assembly comprises a main pipe connected to the cone bucket, the main pipe passes through the cover body of the kiln cover and extends into the inside of the kiln cover, the end of the main pipe located in the kiln cover is connected to the guide branch pipe, and a rectifier plate is obliquely arranged at the connection position between the main pipe and the guide branch pipe, that is, the angle between the plane where the rectifier plate is located and the axis of the main pipe is an acute angle.

[0006] As a further improvement of the above technical solution: the main pipe extends vertically downward into the kiln hood, the main pipe is vertically connected with the guide branch pipe, the end of the main pipe located in the kiln hood is connected to the highest part of the rectifier plate, and the rectifier plate is connected to the guide branch pipe at the lowest part of the intersection line between the main pipe and the guide branch pipe, that is, the guide branch pipe and the rectifier plate are both located in the kiln hood, the guide branch pipe is vertically connected with the main pipe, and the rectifier plate is obliquely connected to the end of the main pipe located in the kiln hood.

[0007] As a further improvement of the above technical solution: the end of the main pipe located in the kiln cover is fixedly connected to the highest part of the rectifier plate, and the rectifier plate is fixedly connected to the diversion branch pipe at the lowest part of the intersection line between the main pipe and the diversion branch pipe.

[0008] As a further improvement of the above technical solution: the shape of the rectifier plate is a flat plate, and the angle between the plane where the rectifier plate is located and the axis of the main pipe is 45° to 75°, such as 45°, 55°, 60°, and 75°.

[0009] As a further improvement of the above technical solution: a plurality of holes are provided on the rectifier plate; the shape of the holes is at least one of a circular hole, an elliptical hole, a plum blossom-shaped hole, and a polygonal hole; the diameter or equivalent diameter of the holes is 10 mm to 15 mm.

[0010] As a further improvement of the above technical solution: the shape of the hole is a round hole.

[0011] As a further improvement of the above technical solution: the opening rate of the rectifier plate is 30% to 50%.

[0012] As a further improvement of the above technical solution: the diameter of the diversion branch pipe is 60% to 100% of the diameter of the main pipe.

[0013] As a further improvement of the above technical solution: the main pipe is sealed and connected to the kiln cover.

[0014] As a further improvement of the above technical solution: the main pipe is fixedly and sealedly connected to the kiln cover.

[0015] As a further improvement of the above technical solution: the main pipe is connected to the kiln cover by welding.

[0016] As a further improvement of the above technical solution: an expansion joint is further provided between the cone bucket and the main pipe.

[0017] As a further improvement of the above technical solution: the expansion joint is a metal expansion joint or a non-metal expansion joint.

[0018] As a further improvement of the above technical solution: a balance pipe is further provided between the cone bucket and the outlet end of the rectifier plate, and the cone bucket is connected to the outlet end of the rectifier plate through the balance pipe.

[0019] As a further improvement of the above technical solution: the pipe opening at the connection between the balance pipe and the cone bucket is tilted downward, and the pipe opening at the other end passes through the cover body of the kiln cover and extends into the inside of the kiln cover and faces the outlet end of the rectifier plate.

[0020] As a further improvement of the above technical solution: the balance pipe is sealed and connected to the kiln cover.

[0021] As a further improvement of the above technical solution: the balance pipe is fixedly and sealedly connected to the kiln cover.

[0022] As a further improvement of the above technical solution: the balance pipe is connected to the kiln cover by welding.

[0023] As a further improvement of the above technical solution: a dust-poking port is also provided on the balancing pipe; the dust-poking port is connected to a pipeline of the balancing pipe located outside the kiln cover.

[0024] As a further improvement of the above technical solution: a flower plate is further provided in the cylinder, and the flower plate is located at the upper end of the filter bag; the filter bag is detachably installed under the flower plate.

[0025] As a further improvement of the above technical solution: a plurality of pulse spray valves are further provided outside the cylinder, the outlets of the pulse spray valves are connected to spray pipes, the spray pipes extend into the cylinder and are located above the flower plate.

[0026] As a further improvement of the above technical solution: the blowing pipe is provided with a blowing hole opening toward the top of the filter bag, and the blowing hole is used for pulse blowing gas into the filter bag to remove dust on the outer surface of the filter bag.

[0027] As a further improvement of the above technical solution: the cylinder is also connected to a top cover; and an exhaust port is provided on the top cover.

[0028] As a further improvement of the above technical solution: the cylinder is fixed on a matching bracket; the bracket is matched with an inspection platform and stairs.

[0029] As a further improvement of the above technical solution: the kiln cover includes a kiln head cover and / or a kiln tail cover of a rotary kiln; and a slag discharge port is provided at the bottom of the kiln cover as appropriate.

[0030] Compared with the prior art, the advantages of the present invention are: (1) In the present invention, an air intake dust removal assembly is provided at the bottom of the cone bucket, and the air intake dust removal assembly extends into the kiln hood. Under the joint action of the main pipe, the rectifier plate and the guide branch pipe, the coupling effect of the mechanisms such as fluid resistance, energy loss, sound wave attenuation, flow field reconstruction, flow direction adjustment, energy dispersion, and buffering can be utilized to effectively reduce the amplitude of the pressure pulsation in the kiln hood caused by the filter spraying and dust cleaning, and reduce the adverse effects on the recycling process of some components of the rotary kiln tail gas. In addition, in the present invention, the air intake dust removal assembly is provided to make the filter and the kiln hood directly connected. Specifically, the air intake dust removal assembly extends into the kiln hood after passing the main pipe through the kiln hood of the rotary kiln, so that the main pipe, the rectifier plate and the guide branch pipe are all located inside the kiln hood. At this time, the air intake dust removal port is located in the kiln hood of the rotary kiln, and no conveying pipeline is provided between the bag filter and the kiln hood, so as to avoid cooling and energy consumption when the tail gas flows through the conveying pipeline, thereby greatly reducing the life cycle cost of the device.

[0031] (2) In the present invention, an expansion joint is provided between the cone bucket and the air intake dust removal assembly, and the expansion joint can be used to compensate for the thermal expansion and contraction of the cylinder, cone bucket, and kiln cover, and to reduce the temperature difference stress borne by the cylinder, cone bucket, air intake dust removal assembly, kiln cover and other components, which is beneficial to improving the safety and reliability of the equipment. In addition, compared with the air intake method of directly entering the cylinder from the side of the cone bucket, in the present invention, under the joint action of the air intake dust removal assembly, the expansion joint and the cone bucket, after the rotary kiln tail gas enters the cylinder, the air flow distribution in the cross section of the cylinder is more uniform, and the operating load of each filter bag is also more uniform, which is beneficial to improving the filtration efficiency and the life of the filter bag.

[0032] (3) In the present invention, a balance pipe is arranged between the cone hopper and the outlet end of the rectifier plate, which can reduce the gas pressure at the outlet of the rectifier plate, reduce the lifting force of the gas on the dust, ensure that the dust can fall smoothly into the kiln cover, prevent dust from being raised, and reduce the pressure pulsation in the kiln cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0034] Figure 1 This is a schematic diagram of the structure of the bag filter for rotary kiln tail gas in Example 1 of the present invention.

[0035] Legend: 1. Exhaust port; 2. Top cover; 3. Pulse jet valve; 4. Cylinder; 5. Filter bag; 6. Cone bucket; 7. Expansion joint; 8. Main pipe; 9. Diversion branch pipe; 10. Slag discharge port; 11. Rectifier plate; 12. Kiln cover; 13. Balance pipe; 14. Dust outlet; 15. Flower plate. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center", "up", "down", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0038] Example 1 like Figure 1 As shown, the bag filter of the rotary kiln exhaust gas in this embodiment includes a cylinder 4, a filter bag 5 is arranged in the cylinder 4, a cone hopper 6 is connected to the bottom of the cylinder 4, an air intake dust removal assembly is connected to the bottom of the cone hopper 6, the air intake dust removal assembly includes a main pipe 8 connected to the cone hopper 6, the main pipe 8 passes through the cover body of the kiln cover 12 and then extends into the interior of the kiln cover 12, the end of the main pipe 8 located in the kiln cover 12 is connected to the guide branch pipe 9, and a rectifier plate 11 is obliquely arranged at the connection position between the main pipe 8 and the guide branch pipe 9.

[0039] In this embodiment, the main pipe 8 extends vertically downward into the interior of the kiln hood 12, the main pipe 8 is vertically connected to the guide branch pipe 9, the end of the main pipe 8 located in the kiln hood 12 is connected to the highest part of the rectifier plate 11, and the rectifier plate 11 is connected to the guide branch pipe 9 at the lowest part of the intersection line between the guide branch pipe 9 and the main pipe 8, that is, an air intake and dust removal assembly is arranged at the bottom of the cone 6, and the air intake and dust removal assembly includes a vertically arranged main pipe 8, an inclined rectifier plate 11 and a horizontally arranged guide branch pipe 9, and the guide branch pipe 9 and the rectifier plate 11 are both located inside the kiln hood 12.

[0040] In this embodiment, the end of the main pipe 8 located in the kiln hood 12 is fixedly connected to the highest part of the rectifier plate 11, and the rectifier plate 11 is fixedly connected to the guide branch pipe 9 at the lowest part of the intersection line between the guide branch pipe 9 and the main pipe 8. The rectifier plate is tilted relative to the main pipe and the guide branch pipe, which helps to form a more reasonable airflow path, makes the gas flow relatively smooth, reduces eddy currents and dead corners, thereby reducing local pressure losses, and also helps to reduce pressure pulsation. It can also effectively prevent dust accumulation on the upper surface of the rectifier plate.

[0041] In this embodiment, the shape of the rectifier plate 11 is a flat plate, and the angle between the plane where the rectifier plate 11 is located and the axis of the main pipe 8 is 45°. In other embodiments, the angle between the plane where the rectifier plate 11 is located and the axis of the main pipe 8 can be 55°, 60°, or 75°.

[0042] In this embodiment, a plurality of holes are formed on the rectifying plate 11 , wherein the holes are circular holes with a diameter of 10 mm. In other embodiments, the diameter of the circular holes may be 12 mm or 15 mm.

[0043] In other embodiments, the shape of the hole may be an elliptical hole, a plum blossom-shaped hole, or a polygonal hole.

[0044] In this embodiment, the opening rate of the rectifier plate 11 is 30%. In other embodiments, the opening rate of the rectifier plate 11 may be 40% or 50%.

[0045] In this embodiment, the diameter of the diversion branch pipe 9 is 60% of the diameter of the main pipe 8. In other embodiments, the diameter of the diversion branch pipe 9 may be 80% or 100% of the diameter of the main pipe 8.

[0046] In this embodiment, the main pipe 8 is sealedly connected to the kiln cover 12, and specifically, the main pipe and the kiln cover are welded together.

[0047] In this embodiment, an air intake and dust removal assembly is arranged at the bottom of the cone bucket 6, and the air intake and dust removal assembly extends into the interior of the kiln cover. Under the joint action of the vertically arranged main pipe 8, the inclined rectifier plate 11 and the horizontally arranged guide branch pipe 9, it has the following advantages: (1) The rectifier plate is set inside the kiln hood. The damping effect of the rectifier plate on the airflow can be used to effectively reduce the pressure pulsation amplitude inside the kiln hood. The details are as follows: ① The small holes on the rectifier plate increase the resistance of the airflow. This resistance causes the velocity and pressure distribution of the airflow to change, thereby reducing the pressure pulsation of the airflow. ② When the gas passes through the small holes of the rectifier plate, a vortex area will be formed near the orifice. The interaction between the airflow, the rectifier plate and the orifice will cause part of the kinetic energy to be converted into heat energy, thereby reducing the energy of the airflow and weakening the pressure pulsation. ③ The rectifier plate can change the propagation path of the sound wave, so that some sound waves interfere with each other and cancel each other out. At the same time, the fluid movement near the orifice will also cause the loss of sound energy, thereby reducing the pressure pulsation. ④ The existence of the rectifier plate will force the airflow to redistribute when passing through the rectifier plate. The originally chaotic or irregular flow will become more uniform after passing through the rectifier plate, thereby reducing the pressure pulsation.

[0048] (2) Placing the diversion branch pipe horizontally inside the kiln hood can also effectively reduce the pressure pulsation inside the kiln hood, as follows: ① The diversion branch pipe redirects the pressure fluctuations that were originally in a vertical or random direction. After leaving the diversion branch pipe, the gas will continue to flow along its outlet direction, that is, diffuse toward the rotary kiln cylinder. This diffuse flow helps to disperse the gas into a larger space, thereby reducing the impact of the gas on the kiln hood area and the pressure pulsation. ② By changing the direction of the airflow, the diversion branch pipe can disperse the originally concentrated pressure pulsation energy over a larger area, thereby weakening the local pressure pulsation intensity. ③ When the gas is discharged from the diversion branch pipe and hits the wall and internal components of the rotary kiln cylinder, part of the kinetic energy will be absorbed or reflected by the cylinder wall and internal components, which also helps to reduce the amplitude of the pressure pulsation. ④ The design of the diversion branch pipe can also include appropriate cross-sectional area changes to adjust the gas flow rate and further stabilize the pressure.

[0049] It can be seen that in the present invention, an air intake and dust removal assembly is arranged at the bottom of the cone hopper, and the air intake and dust removal assembly extends into the interior of the kiln hood. Under the joint action of the main pipe, the rectifier plate and the guide branch pipe, the coupling effect of mechanisms such as fluid resistance, energy loss, sound wave attenuation, flow field reconstruction, flow direction adjustment, energy dispersion, and buffering effect can be utilized to effectively reduce the amplitude of pressure pulsation in the kiln hood caused by the filter blowing dust cleaning, thereby reducing the adverse effects on the recovery and utilization process of some components of the rotary kiln exhaust gas.

[0050] In addition, in the present invention, an air intake dust unloading assembly is arranged at the bottom of the cone hopper to directly connect the filter with the kiln hood. Specifically, the air intake dust unloading assembly extends into the interior of the kiln hood by passing the main pipe through the kiln hood of the rotary kiln, so that the main pipe, the rectifier plate and the guide branch pipe are all located inside the kiln hood. At this time, the air intake dust unloading port is located in the kiln hood of the rotary kiln, and no conveying pipeline is arranged between the bag filter and the kiln hood, so as to avoid cooling and energy consumption when the exhaust gas flows through the conveying pipeline, thereby greatly reducing the life cycle cost of the device.

[0051] In this embodiment, an expansion joint 7 is further provided between the cone bucket 6 and the main pipe 8. In this embodiment, the expansion joint 7 is a metal expansion joint. In other embodiments, the expansion joint 7 may also be a non-metal expansion joint.

[0052] In the present invention, an expansion joint is arranged between the cone bucket and the air intake dust removal assembly, and the expansion joint can be used to compensate for the thermal expansion and contraction of the cylinder, the cone bucket and the kiln hood, and to reduce the temperature difference stress borne by the cylinder, the cone bucket, the air intake dust removal assembly, the kiln hood and other components, which is beneficial to improving the safety and reliability of the equipment.

[0053] In the present invention, the tail gas of the rotary kiln enters the cone bucket and the cylinder through the air intake dust removal assembly and the expansion joint in sequence, and the dust dropped from the filter bag in the process of pulse spray dust cleaning or reverse airflow dust cleaning in sequence falls into the kiln cover through the cone bucket, the expansion joint and the air intake dust removal assembly, that is, the air intake dust removal assembly has both air intake and dust removal functions. The air intake dust removal assembly is connected to the bottom of the cone bucket, so that the air intake and dust removal ports of the cone bucket are combined into one, and the structure is simpler.

[0054] In addition, compared with the air intake method of directly entering the cylinder from the side of the cone bucket, in the present invention, under the joint action of the air intake dust removal assembly, the expansion joint and the cone bucket, after the rotary kiln tail gas enters the cylinder, the air flow distribution in the cross section of the cylinder is more uniform, and the operating load of each filter bag is also more uniform, which is beneficial to improving the filtration efficiency and the life of the filter bag.

[0055] In this embodiment, a balancing pipe 13 is further provided between the cone hopper 6 and the outlet end of the rectifier plate 11, wherein the pipe opening at the connection between the balancing pipe 13 and the cone hopper 6 is inclined downward, and the pipe opening at the other end passes through the cover body of the kiln hood 12 and extends into the interior of the kiln hood 12 and faces the outlet end of the rectifier plate 11.

[0056] In the present invention, a balance pipe is arranged between the cone hopper and the outlet end of the rectifier plate, which can reduce the gas pressure at the outlet of the rectifier plate, reduce the lifting force of the gas on the dust, ensure that the dust can fall smoothly into the kiln cover, reduce dust, and reduce the pressure pulsation in the kiln cover, as follows: ① When the dust falls from the rectifier plate, due to the presence of gas, a certain positive pressure area will be formed at the outlet of the rectifier plate, which will cause the dust to be subjected to an upward lifting force. Further, one end of the balance pipe is connected to the bottom of the rectifier plate in the air intake dust removal assembly, and the other end is connected to the cone hopper of the bag filter, so that a pressure release channel can be provided during the dust falling process. ② The balance pipe allows part of the gas at the outlet of the rectifier plate to flow back to the cone hopper through the balance pipe, thereby reducing the gas pressure at the outlet of the rectifier plate and reducing the pressure pulsation in the kiln cover. This pressure reduction and pulsation reduction help to reduce the upward lifting force of the gas on the dust, making the dust more susceptible to the effect of gravity and flow downward. ③ After reducing the gas lifting force, dust is easier to enter the kiln cover and then discharged from the slag discharge port in the kiln cover, reducing the possibility of dust being blown up and suspended by the air flow again, thereby reducing the occurrence of dust. In addition, the pipe opening of the balance pipe at the cone bucket is tilted downward, which makes it easier for dust from the balance pipe to fall into the expansion joint and the air intake dust removal component, which can reduce the load on the filter bag.

[0057] In this embodiment, the balance pipe 13 is fixedly and sealedly connected to the kiln cover 12, specifically, is welded.

[0058] In this embodiment, a dust-poking port 14 is further provided on the balancing pipe 13 , and the dust-poking port 14 is connected to a pipeline of the balancing pipe 13 located outside the kiln cover 12 .

[0059] In the present invention, when dust bridges appear in the cone bucket and are difficult to fall into the air intake dust removal component, the flange cover of the dust poking port is removed or the valve of the dust poking port is opened, and a tubular or rod-shaped device is inserted to make the device reciprocate and swing in the cone bucket to break the dust bridge phenomenon in the cone bucket.

[0060] In this embodiment, a flower plate 15 is further provided in the cylinder 4 , and the flower plate 15 is located at the upper end of the filter bag 5 ; the filter bag 5 is detachably installed below the flower plate 15 .

[0061] In this embodiment, a pulse spray valve 3 is further provided outside the cylinder 4, and the outlet of the pulse spray valve 3 is connected to a spray pipe (not shown in the figure), which extends into the cylinder 4 and is located above the flower plate 15. The spray pipe is provided with a spray hole opening toward the top of the filter bag 5, which is used to remove dust on the outer surface of the filter bag.

[0062] In this embodiment, a top cover 2 is connected to the top of the cylinder 4, and an exhaust port 1 is provided on the top cover 2, and the exhaust gas filtered by the filter bag is discharged through the exhaust port.

[0063] In this embodiment, the cylinder 4 is fixed on a supporting bracket, and the supporting bracket is provided with a maintenance platform and stairs.

[0064] In this embodiment, the kiln hood 12 is a kiln tail hood of a rotary kiln. In another embodiment, the kiln hood 12 is a kiln head hood of a rotary kiln. A slag discharge port 10 is provided at the bottom of the kiln hood 12 .

[0065] It can be seen from the above results that, compared with conventional bag filters, in the bag filters of the present invention, an air intake dust removal assembly is arranged at the bottom of the cone bucket. Under the joint action of the main pipe, the rectifier plate and the guide branch pipe, the filter is directly connected to the kiln hood, which can avoid the bag filter and the rotary kiln being far apart, and can prevent some components in the exhaust gas from condensing into liquids, reduce the blockage of the inlet pipe and the filter bag, the negative pressure in the inlet pipe and the filter, and the large pressure pulsation amplitude in the kiln hood caused by the filter dust cleaning. Abnormal phenomena can be avoided, such as improving the output rate, safety and reliability of the equipment and reducing the life cycle cost of the equipment.

[0066] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A bag filter for rotary kiln tail gas, characterized in that: The invention comprises a cylinder (4), wherein a filter bag (5) is arranged inside the cylinder (4), a cone hopper (6) is connected to the bottom of the cylinder (4), an air intake dust removal assembly is connected to the bottom of the cone hopper (6), the air intake dust removal assembly comprises a main pipe (8) connected to the cone hopper (6), the main pipe (8) passes through the cover of the kiln cover (12) and then extends vertically downward into the inside of the kiln cover (12), the end of the main pipe (8) located inside the kiln cover (12) is vertically connected to a guide branch pipe (9), and a rectifying plate (11) is obliquely arranged at the connection part between the main pipe (8) and the guide branch pipe (9); the end of the main pipe (8) located inside the kiln cover (12) is connected to the highest part of the rectifying plate (11), and the rectifying plate (11) is connected to the guide branch pipe (9) at the lowest part of the intersection line between the guide branch pipe (9) and the main pipe (8).

2. The bag filter according to claim 1, characterized in that: The angle between the plane where the rectifying plate (11) is located and the axis of the main pipe (8) is 45° to 75°.

3. The bag filter according to claim 2, characterized in that: The rectifying plate (11) is provided with a plurality of holes; the shape of the holes is at least one of a circular hole, an elliptical hole, a quincunx-shaped hole, and a polygonal hole, and the diameter or equivalent diameter of the holes is 10 mm to 15 mm; the opening rate of the rectifying plate (11) is 30% to 50%; the diameter of the diversion branch pipe (9) is 60% to 100% of the diameter of the main pipe (8).

4. The bag filter according to any one of claims 1 to 3, characterized in that: An expansion joint (7) is also provided between the cone bucket (6) and the main pipe (8); the expansion joint (7) is a metal expansion joint or a non-metal expansion joint.

5. The bag filter according to any one of claims 1 to 3, characterized in that: A balance pipe (13) is further provided between the cone hopper (6) and the outlet end of the rectifying plate (11); the pipe opening of the balance pipe (13) at the connection between the cone hopper (6) and the cone hopper (6) is inclined downward, and the pipe opening at the other end passes through the cover body of the kiln cover (12) and extends into the interior of the kiln cover (12) and faces the outlet end of the rectifying plate (11).

6. The bag filter according to claim 5, characterized in that: The balancing pipe (13) is also provided with a dust-poking port (14); the dust-poking port (14) is connected to a pipeline of the balancing pipe (13) located outside the kiln cover (12).

7. The bag filter according to any one of claims 1 to 3, characterized in that: A flower plate (15) is also provided in the cylinder (4), and the flower plate (15) is located at the upper end of the filter bag (5); the filter bag (5) is detachably mounted below the flower plate (15).

8. The bag filter according to claim 7, characterized in that: A pulse spray valve (3) is also provided outside the cylinder (4), and an outlet of the pulse spray valve (3) is connected to a spray pipe, which extends into the cylinder (4) and is located above the flower plate (15), and a spray hole opening toward the top of the filter bag (5) is provided on the spray pipe.

9. The bag filter according to any one of claims 1 to 3, characterized in that: A top cover (2) is also connected to the top of the cylinder (4); an exhaust port (1) is provided on the top cover (2).

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