A short-process metal filter bag dust collector and flue gas dust removal method

Abstract

The application provides a short-process metal filter bag dust collector and a flue gas dust removal method. The dust collector comprises a box body, an airflow distribution device, a dust hopper and a plurality of filter bags. The dust hopper is connected with the lower part of the box body and the two are communicated. The airflow distribution device is arranged in the middle part of the box body. The height of the airflow distribution device is equal to that of the filter bag. The filter bags are arranged in the box body and are uniformly distributed around the periphery of the airflow distribution device. The center of the top of the box body is provided with an air inlet pipe. The top of the box body is provided with a clean gas chamber. The clean gas chamber is arranged in one circle around the air inlet pipe. An air outlet is formed in one side of the clean gas chamber. The filter bag is used for filtering flue gas. The top of the filter bag is open and is communicated with the clean gas chamber. The airflow distribution device is arranged in the middle part of the box body. The air inlet pipe is arranged at the top of the box body. The flue gas enters the dust collector from the top, passes through the airflow distribution device, 50% of the flue gas flows through the upper part of the filter bag from the upper part of the airflow distribution device to complete the filtration and enters the clean gas chamber. The flow path of the flue gas is reduced, the efficiency is improved and the operation resistance is reduced.

Description

Technical Field

[0001] This invention belongs to the field of flue gas dust removal technology, specifically relating to a short-process metal filter bag dust collector and a flue gas dust removal method. Background Technology

[0002] To address climate change, my country has made solemn commitments to "strive to peak carbon dioxide emissions before 2030 and endeavor to achieve carbon neutrality before 2060." Two key measures for carbon neutrality are afforestation and energy conservation and emission reduction, with energy conservation and emission reduction being of paramount importance. Energy conservation and emission reduction in the steel industry, especially ultra-low emissions from converter steelmaking, have become one of the important indicators for steel mills. Since 2019, with the adjustment of the steel industry's industrial structure and the increasing requirements for energy conservation and emission reduction, five ministries, including the Ministry of Ecology and Environment, jointly issued the "Opinions on Promoting the Implementation of Ultra-Low Emissions in the Steel Industry," setting the particulate matter emission concentration from converter flue gas at 10 mg / Nm³. 3 Therefore, the dry dust removal systems for converters built before 2019 do not meet the ultra-low emission requirements. In addition, converter expansion and the old dust removal systems have become dilapidated, causing many steel plants' primary flue gas dry dust removal systems to be unable to meet the increasingly stringent ultra-low emission requirements, and urgently need to be upgraded and retrofitted for ultra-low emission.

[0003] Baghouse dust collectors are widely used in various industrial fields due to their high dust removal efficiency and stable operation. Through the extensive use of baghouse dust collectors, it has been found that reducing airflow resistance, extending filter bag lifespan, and reducing vibration and noise are urgent problems that need to be solved. The airflow distribution within the baghouse is a key factor determining the dust collector's performance and lifespan. Uneven airflow can easily cause filter bag damage in certain locations within the baghouse, while filter bags in other locations play a less significant role in dust removal. Most damaged filter bags in baghouse dust collectors are concentrated downstream, which is closely related to the airflow conditions inside the housing. Under the current dust collector structure, the airflow entering the collector flows along the sidewall of the ash hopper, resulting in poor uniformity throughout the entire dust collector space. Therefore, properly adjusting the airflow flow and distribution can reduce operating resistance, extend filter bag lifespan, and reduce vibration and noise. Summary of the Invention

[0004] The purpose of this invention is to provide a short-process metal filter bag dust collector that overcomes the aforementioned technical problems in the prior art.

[0005] Another objective of this invention is to provide a flue gas dust removal method that, while ensuring that the flue gas from the converter primary dust removal process can stably meet the requirements for ultra-low emissions, effectively reduces the flue gas flow path, reduces system resistance loss, lowers system energy consumption, and effectively reduces equipment construction investment and operation and maintenance.

[0006] Therefore, the technical solution provided by the present invention is as follows: A short-process metal bag dust collector includes a housing, an airflow distribution device, a dust hopper, and multiple filter bags. The dust hopper is connected to the lower part of the housing and the two are in communication. The airflow distribution device is located in the middle of the housing and its height is equal to that of the filter bags. The filter bags are located inside the housing and are evenly distributed around the outer periphery of the airflow distribution device. An air inlet pipe is located at the center of the top of the housing. A clean air chamber is provided at the top of the housing and is arranged around the circumference of the air inlet pipe. An air outlet is provided on one side of the clean air chamber. The filter bags are used to filter flue gas, and the top of the filter bags is open and communicates with the clean air chamber.

[0007] The airflow distribution device has multiple guide holes evenly distributed from top to bottom, and the airflow distribution device is a frustum shape with a larger top and a smaller bottom.

[0008] The clean air chamber is equipped with an annular nitrogen jet cleaning device, which is used for cleaning the filter bags. The annular nitrogen jet cleaning device and the filter bags are connected by a tube sheet.

[0009] The bottom end of the airflow distribution device is connected to an arc-shaped airflow distribution disk, the bottom surface of which is spherical and has multiple exhaust holes.

[0010] The annular nitrogen blowing device includes a blowing manifold, a pulse valve, a blowing pipe, and a nozzle, with at least one nozzle corresponding to each filter bag.

[0011] The annular nitrogen blowing device is divided into perforated plates, and adjacent perforated plates can be detachably connected.

[0012] The box body is cylindrical, and the filter bag is a stainless steel metal filter bag.

[0013] An explosion relief valve is installed on the lower side of the enclosure.

[0014] A flue gas dust removal method uses a short-process metal filter bag dust collector. Flue gas enters the dust collector from the top inlet pipe, passes through the airflow distribution device, and is discharged from the guide holes at various heights of the airflow distribution device. After being filtered by the filter bags, the flue gas enters the clean air chamber and is finally discharged through the outlet. The filtered flue gas dust falls into the ash hopper for collection.

[0015] During the gas recovery stage of the blowing process, when no flue gas enters the dust collector, the annular nitrogen jet cleaning device is turned on to perform offline cleaning of all filter bags in the dust collector.

[0016] The beneficial effects of this invention are: The short-process metal filter bag dust collector provided by this invention uses an airflow distribution device in the middle of the housing and an air inlet pipe at the top of the housing to allow flue gas to enter the dust collector from the top. After passing through the airflow distribution device, 50% of the flue gas flows from the upper part of the annular porous airflow distribution device through the upper part of the filter bag to complete filtration and enter the clean air chamber. This reduces the flow path of this part of the flue gas and also reduces the problem of excessively high local air velocity at the tank opening when using traditional bottom or side air inlet, thereby improving efficiency and reducing operating resistance.

[0017] The device of the present invention prevents flue gas from directly hitting the ash hopper and generating secondary dust by setting an arc-shaped airflow distribution plate at the end of the air inlet pipe. At the same time, it can effectively prevent ash accumulation in the pipe and promote the uniform radial distribution of the end flue gas to the lower end of the filter bag.

[0018] The dust collector housing is an explosion-proof circular design and is equipped with a safety relief valve, which solves the problem of periodic explosion of converter flue gas and effectively protects the safety of the equipment. The cylindrical shape effectively eliminates dead corners in the equipment, and makes the periodically circulating gas and air flow in a plunger shape, so that they no longer mix easily, reducing the possibility of system explosion.

[0019] The annular nitrogen jet cleaning device of the dust collector is installed around the clean air chamber and arranged in a circular shape around the air inlet pipe at the center of the top of the box. Each 90-degree unit is a standard unit, and the entire dust collector is divided into four standard units. The cleaning process is controlled by an independent jet cleaning program to ensure that the cleaning process is completed in sequence within 6 minutes for all four units, that is, all filter bags in the entire dust collector. This also facilitates installation and maintenance. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of one embodiment of the present invention; Figure 2 This is a top view of one embodiment of the circular perforated plate of the present invention; Figure 3 This is a schematic diagram of the airflow direction in a traditional baghouse dust collector.

[0021] In the diagram: 1. Ash hopper; 2. Arc-shaped airflow distribution plate; 3. Box body; 4. Filter bag; 5. Explosion relief valve; 6. Airflow distribution device; 7. Tube plate; 8. Annular nitrogen pulse jet system; 9. Clean air chamber; 10. Air outlet; 11. Air inlet pipe. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0023] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0024] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0025] Example 1 This embodiment provides a short-process metal filter bag dust collector, such as Figure 1 As shown, the device includes a housing 3, an airflow distribution device 6, an ash hopper 1, and multiple filter bags 4. The ash hopper 1 is connected to the lower part of the housing 3 and the two are in communication. The airflow distribution device 6 is located in the middle of the housing 3, and the height of the airflow distribution device 6 is equal to that of the filter bags 4. The filter bags 4 are located inside the housing 3 and are evenly distributed around the outer periphery of the airflow distribution device 6. The top center of the housing 3 is an air inlet pipe 11. The top of the housing 3 is provided with a clean air chamber 9, which is arranged in a circle around the air inlet pipe 11. An air outlet 10 is opened on one side of the clean air chamber 9. The filter bags 4 are used to filter the flue gas, and the top of the filter bags 4 is open and communicates with the clean air chamber 9.

[0026] The air inlet of this invention is located at the top of the dust collector. The flue gas enters the airflow distribution device 6 located in the middle of the housing 3 through the air inlet pipe 11, so that the flue gas is evenly distributed in the vertical direction and enters the filter bag 4. The airflow distribution is reasonably adjusted, thereby reducing the operating resistance and shortening the flow path of some flue gas. This overcomes the technical problem that most of the damaged filter bags 4 in the existing bag dust collectors are concentrated at the downstream of the dust collector, thus extending the service life of the filter bags 4 and reducing vibration and noise.

[0027] The schematic diagram of the airflow direction of a traditional bag filter is shown below. Figure 3 As shown, flue gas enters the dust collector from the bottom inlet. Due to inertia, the flue gas rushes straight to the opposite cylinder wall. Part of the flue gas is deflected and moves upward through the gaps in the filter bags 4, gradually passing from the bottom to the top of the filter bags 4. Another part of the flue gas, after being deflected by the cylinder wall, forms a vortex at the top of the ash hopper 1. This not only results in a long flue gas flow path and high resistance, but also generates local vortices, leading to problems such as poor dust removal and secondary dust generation. Because the entire flue gas flow path is long, the pressure loss during equipment operation is also relatively large.

[0028] Example 2 Based on Example 1, this example provides a short-process metal filter bag dust collector. The airflow distribution device 6 has multiple guide holes evenly distributed from top to bottom. The airflow distribution device 6 is a frustum shape with a larger top and a smaller bottom.

[0029] The airflow distribution device 6 has the function of uniformly distributing the flue gas and the airflow. When the flue gas flows through the flue gas, a portion of the flue gas can directly enter the upper part of the dust collector through the uniformly distributed guide holes on the inlet pipe 11. More than 50% of the flue gas passes through the guide holes on the upper part of the inlet pipe 11 instead of passing through the entire height of the housing 3, which effectively reduces the flow path of the flue gas, realizes the short flow path of the flue gas, and at the same time reduces the wind speed at the canister opening in the dust collector, thereby reducing the operating resistance and energy consumption of the equipment. Example 3 Based on Example 1, this example provides a short-process metal filter bag dust collector. The clean air chamber 9 is equipped with an annular nitrogen jet cleaning device, which is used for cleaning the filter bag 4. The annular nitrogen jet cleaning device and the filter bag are connected through a tube sheet 7.

[0030] The tube sheet 7 is placed above the metal filter bag, and the annular nitrogen jetting device is placed above the tube sheet 7. The tube sheet 7 has many through holes. The nitrogen gas sprayed by the annular nitrogen jetting device enters the filter bag through the through holes, realizing the dust removal function and preventing explosion.

[0031] Example 4 Based on Example 1, this example provides a short-process metal filter bag dust collector. The bottom end of the airflow distribution device 6 is connected to an arc-shaped airflow distribution disk 2. The bottom surface of the arc-shaped airflow distribution disk 2 is spherical, and multiple exhaust holes are opened on the sphere.

[0032] In this embodiment, by setting an arc-shaped airflow distribution plate 2, the flue gas is dispersed in all directions, thereby avoiding the flue gas from directly rushing into the ash hopper 1 and generating secondary dust. At the same time, through reasonable gaps and shape structure, ash accumulation inside the pipe can be effectively prevented, and the end flue gas can be evenly distributed radially to the lower end of the filter bag 4.

[0033] Example 5 Based on Example 1, this example provides a short-process metal filter bag dust collector. The annular nitrogen jetting device includes a jetting distribution manifold, a pulse valve, jetting pipes, and nozzles. Each filter bag 4 corresponds to at least one nozzle. The jetting distribution manifold is connected to multiple jetting pipes, which are connected to nozzles. The pulse valve is installed on the jetting pipe.

[0034] like Figure 1 As shown, the annular nitrogen jetting device is installed in the annular space between the clean air chamber 9 and the air inlet pipe 11, hence its annular shape. Air is intermittently supplied to the nozzles via a pulse valve to clean the filter bag 4.

[0035] Example 6 Based on Example 1, this example provides a short-process metal filter bag dust collector, wherein the annular nitrogen blowing device is divided into multiple standard units, and two adjacent standard units can be detachably connected.

[0036] In this embodiment, to achieve modularity and standardization, the annular nitrogen injection device is arranged circumferentially around the air inlet pipe at the center of the top of the housing 3, with 90 degrees as a standard unit. The perforated plate 7 also consists of 4 standard units (e.g., Figure 2 As shown in the figure, the entire dust collector is divided into four standard units, which facilitates installation and maintenance.

[0037] The cleaning process is controlled by an independent pulse-jet cleaning program, ensuring that all filter bags 4 in the four sector units (i.e., the entire dust collector) are cleaned sequentially within a specified time. Simultaneous cleaning of all four sector units is also possible.

[0038] Example 7 Based on Example 1, this example provides a short-process metal filter bag dust collector, wherein the housing 3 is cylindrical and the filter bag 4 is a stainless steel metal filter bag. An explosion relief valve 5 is provided on the lower side of the housing 3.

[0039] The cylindrical housing 3 effectively eliminates dead zones in the equipment, allowing the periodically circulating gas and air to flow in a plunger-like manner, preventing them from easily mixing and reducing the possibility of system explosion. In addition, a safety explosion relief valve 5 is installed, which completely solves the problem of periodic explosion of converter flue gas and effectively protects the safety of the equipment.

[0040] Example 8 This embodiment provides a flue gas dust removal method using a short-flow metal filter bag dust collector. Flue gas enters the dust collector from the top inlet pipe 11, passes through the airflow distribution device 6, and is discharged from the guide holes at various heights of the airflow distribution device 6. After being filtered by the filter bag 4, the flue gas enters the clean air chamber 9 and is finally discharged through the air outlet 10. The filtered soot falls into the ash hopper 1 for collection.

[0041] During the gas recovery stage of the blowing process, when no flue gas enters the dust collector, the annular nitrogen jet cleaning device is turned on to clean all filter bags 4 in the dust collector offline.

[0042] In this invention, flue gas enters the dust collector through the top inlet, passes through the airflow distribution device 6 vertically arranged in the center of the dust collector cylinder, and is evenly distributed vertically within the dust collector housing 3. The gas then passes through the filter bags 4 at various heights within the dust collector housing 3 before entering the clean air chamber 9. Due to the regular cyclical nature of converter production, which generally consists of stages such as adding scrap steel, adding iron, blowing, tapping, and slag splashing for furnace protection, the blowing stage includes two phases: converter gas release and recovery. The gas recovery phase typically lasts about 7 to 10 minutes. The stage with the highest dust concentration and flue gas volume is the release phase during the blowing stage. During other times, the flue gas volume and dust concentration are relatively low, especially during the gas recovery phase of the blowing stage, where no flue gas passes through the dust collection equipment. Therefore, this invention utilizes this 7 to 10-minute phase to perform offline cleaning of all filter bags 4 within the dust collector.

[0043] This invention employs a reliable fixed pulse jet cleaning device, which ensures effective cleaning force and effect. It can be carried out simultaneously in four fan-shaped areas, ensuring that all filter bags 4 of the entire dust collector are cleaned once within 6 minutes (gas recovery stage). In case of special circumstances such as interruption of recovery, the dust collector can also complete the entire cleaning process. The program will automatically identify that the offline cleaning has not been effectively completed for that furnace. At this time, the dust collector will select the non-blowing and venting stage with less converter flue gas to carry out online cleaning, so as to reduce the interference factors such as secondary dust caused by flue gas volume.

[0044] This invention targets a dry dust removal system for primary flue gas from converters, and can also be used in flue gas dust removal systems for other industrial kilns paired with dry electrostatic precipitators to meet increasingly stringent ultra-low emission requirements. This invention ensures equipment safety, effectively prevents gas leaks and explosions, and solves the problem that dry dust removal systems cannot meet ultra-low emission standards; it reduces the flue gas flow path, lowers system resistance, and reduces overall energy consumption; it incorporates centrifugal cleaning and online cleaning functions based on the converter process, resulting in better cleaning performance than ordinary bag filters; it reduces construction investment and equipment maintenance during production, and significantly reduces the production failure rate; and it extends the service life of the equipment.

[0045] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A short-process metal filter bag dust collector, characterized in that: The device includes a housing, an airflow distribution device, an ash hopper, and multiple filter bags. The ash hopper is connected to the lower part of the housing and the two are in communication. The airflow distribution device is located in the middle of the housing and its height is equal to that of the filter bags. The filter bags are located inside the housing and are evenly distributed around the outer periphery of the airflow distribution device. The top center of the housing has an air inlet pipe, and the top of the housing has a clean air chamber arranged around the air inlet pipe. An air outlet is opened on one side of the clean air chamber. The filter bags are used to filter the flue gas, and the top of the filter bags is open and communicates with the clean air chamber. The airflow distribution device has multiple guide holes evenly distributed from top to bottom. The airflow distribution device is a frustum shape with a larger top and a smaller bottom. The upper guide holes are used to allow more than 50% of the flue gas to enter the upper part of the dust collector, thereby achieving a short flue gas flow path. The bottom end of the airflow distribution device is connected to an arc-shaped airflow distribution disk, the bottom surface of which is spherical and has multiple exhaust holes. The housing is cylindrical, the filter bag is a stainless steel metal filter bag, and a pressure relief valve is provided on the lower side of the housing.

2. The short-process metal filter bag dust collector according to claim 1, characterized in that: The clean air chamber is equipped with an annular nitrogen jet cleaning device, which is used for cleaning the filter bags. The annular nitrogen jet cleaning device and the filter bags are connected by a tube sheet.

3. A short-process metal filter bag dust collector according to claim 2, characterized in that: The annular nitrogen blowing device includes a blowing manifold, a pulse valve, a blowing pipe, and a nozzle, with at least one nozzle corresponding to each filter bag.

4. A short-process metal filter bag dust collector according to claim 2, characterized in that: The annular nitrogen blowing device is divided into perforated plates, and adjacent perforated plates can be detachably connected.

5. A method for flue gas dust removal, using a short-process metal filter bag dust collector as described in any one of claims 1-4, characterized in that: Flue gas enters the dust collector through the top inlet pipe, passes through the airflow distribution device, and is discharged through the guide holes at various heights of the airflow distribution device. After being filtered by the filter bags, the flue gas enters the clean air chamber and is finally discharged through the outlet. The filtered flue gas falls into the ash hopper for collection.

6. The flue gas dust removal method according to claim 5, characterized in that: During the gas recovery stage of the blowing process, when no flue gas enters the dust collector, the annular nitrogen jet cleaning device is turned on to perform offline cleaning of all filter bags in the dust collector.

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