A dry dedusting system for converter gas

Abstract

The utility model discloses a kind of dry dedusting systems for converter gas, belong to converter gas purification and recovery technical field.This system includes dust-containing gas pipeline, clean gas pipeline, nitrogen backflushing ash removal device, nitrogen seal ash storehouse and several parallelly connected dust collector units;Dust collector unit includes bag filter, first ash valve, intermediate ash bin, second ash valve and nitrogen ash conveying device;Bag filter includes conical hopper, cylindrical shell and head structure from bottom to top in order, and the middle part of cylindrical shell is provided with several stainless steel metal filter bags arranged along axial and longitudinal direction, can adapt to converter gas operating condition, so that converter gas is dedusted by stainless steel metal filter bag to reach emission standard;Nitrogen backflushing ash removal device realizes safe ash removal by gas distribution box and backflushing pipe, avoids ferrous oxide dust meeting oxygen exothermic, reduces explosion risk, solves the problem that traditional LT method exists explosion risk and cannot meet emission requirement when carrying out dust removal to converter gas.

Description

Technical Field

[0001] This utility model relates to the field of converter gas purification and recovery technology, specifically to a dry dust removal system for converter gas. Background Technology

[0002] Converter gas is produced in the steelmaking process in a converter. It mainly consists of 60-80% carbon monoxide, 15-20% carbon dioxide, small amounts of nitrogen, hydrogen, and trace amounts of oxygen. When the converter gas is ejected from the furnace mouth, the temperature reaches as high as 1450-1500℃, and it carries a large amount of ferrous oxide dust and ferric oxide dust. It needs to be cooled and dust removed before it can be recovered and used.

[0003] Currently, mature methods for treating converter gas include the OG (Oxygen Converter Gas Recovery) method and the LT (Low Temperature) method. The OG method uses a micro-pressure differential at the furnace inlet to control the flue gas volume. The hood and skirt employ a high-temperature hot water closed-loop cooling system, and the flue uses vaporization cooling. Water spraying is used throughout the entire dust removal system to achieve flue gas cooling and dust removal. The OG method is the most widely used and mature technology in the field of converter gas recovery. After continuous improvement, it has now reached its fourth generation, possessing characteristics such as safety, reliability, low maintenance, and low system equipment cost. However, the biggest drawbacks of this method are high energy consumption, huge water consumption, complex wastewater treatment, and high operating costs.

[0004] The LT method (Lurgi Thyssen Technology, dry dust removal converter gas recovery technology) mainly consists of an evaporative cooler, an electrostatic precipitator, a gas cooler, and a switching station. An evaporative cooler is installed after the gasification cooling flue, where sprayed water cools and conditions the flue gas. The flue gas temperature exiting the evaporative cooling tower is approximately 180°C. It then enters the electrostatic precipitator, where dust is removed and the gas is recovered, yielding dry dust. The advantage of the LT method is its lower water consumption compared to the OG method and the elimination of the need for wastewater treatment facilities. However, this technology carries the risk of explosion caused by sparks from the electrostatic precipitator discharge, which could severely impact normal converter production. Furthermore, with increasingly stringent environmental standards in the steel industry (requiring particulate matter emissions ≤10mg / L), further risks are emerging. ), LT method 20~50mg / The dust concentration at the outlet is insufficient to meet emission requirements.

[0005] Baghouse dust collectors are a type of high-efficiency dust removal equipment (outlet dust concentration <10mg / L). While widely used in industrial applications, traditional filter materials have long been limited in their application in converter gas purification due to insufficient high-temperature resistance (300-500℃). In recent years, with breakthroughs in new high-temperature resistant filter material technology, a few steel plants have attempted to transplant blast furnace gas baghouse dust collection technology to converter gas purification systems. However, simply copying existing technologies is insufficient to fully adapt to the special operating conditions of converter gas. Specifically, the main component of converter gas dust is ferrous oxide, which is unstable and easily oxidized, releasing heat during oxidation. When using baghouse dust collection, the filter bag surface should not be covered with excessive dust to prevent the heat released during oxidation from accumulating and rapidly heating up, burning the filter bag. Since the converter smelting cycle is divided into oxygen blowing and non-oxygen blowing periods, the CO content in the flue gas is high during the oxygen blowing period. Low content, considered as converter gas; during non-oxygen blowing period, it mainly contains The air in the converter is considered the converter flue gas; in one cycle of converter steelmaking, the oxygen blowing period and the non-oxygen blowing period alternate, and the flue gas entering the dust removal system is also the converter gas containing oxygen. The switching between converter flue gas and other gases poses a certain degree of explosion risk, requiring strict control over the simultaneous presence of the three explosive elements in the dust removal system.

[0006] Therefore, how to design a dry dust removal system that meets emission standards and is safe and stable has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a dry dust removal system for converter gas, so as to overcome the problems of explosion risk and failure to meet emission requirements when using the LT method to remove dust from converter gas in the prior art.

[0008] The present invention solves the above-mentioned technical problems through the following technical solution:

[0009] A dry dust removal system for converter gas includes a dust-laden gas pipeline, a clean gas pipeline, a nitrogen backflushing cleaning device, a nitrogen-sealed ash silo, and several parallel-connected dust collector units. Each dust collector unit includes a bag filter, a first ash discharge valve, an intermediate ash silo, a second ash discharge valve, and a nitrogen ash conveying device. The bag filter, from bottom to top, includes a conical ash hopper, a cylindrical shell, and a head structure. Several stainless steel metal filter bags are arranged in an array along the axial and longitudinal directions in the middle of the cylindrical shell.

[0010] The nitrogen backflushing cleaning device includes a gas distribution box and several backflushing pipes arranged axially along the stainless steel metal filter bags. The gas distribution box is located outside the bag filter. One end of each backflushing pipe is connected to the gas distribution box, and the other end passes through the cylindrical shell and is positioned above the stainless steel metal filter bags. Several nozzles are installed on the backflushing pipes, and each nozzle corresponds to a stainless steel metal filter bag. The output port of the conical ash hopper is sequentially connected to the first ash discharge valve, the intermediate ash silo, the second ash discharge valve, and the input port of the nitrogen ash conveying device. The output port of the nitrogen ash conveying device is connected to the top inlet of the nitrogen-sealed ash silo. The upper part of the cylindrical shell is the clean air chamber, and the lower part of the cylindrical shell is the dusty gas chamber. The dusty gas chamber is connected to the outlet of the dusty coal gas pipeline, and the clean air chamber is connected to the inlet of the clean coal gas pipeline.

[0011] During dust removal, the dry dust removal system is connected to the converter system, which includes a converter gas waste heat recovery device and a gas cooler connected in sequence; the inlet of the dusty gas pipeline is connected to the converter gas waste heat recovery device, and the outlet of the clean gas pipeline is connected to the gas cooler.

[0012] A further improvement of this utility model is that it also includes a first isolation device and a second isolation device, wherein the dust gas chamber is connected to the outlet of the dust-containing gas pipeline via the first isolation device, and the clean gas chamber is connected to the inlet of the clean gas pipeline via the second isolation device.

[0013] A further improvement of this utility model is that it also includes a venting bypass pipe and a third isolation device, wherein the dust-containing gas pipe is connected to the clean gas pipe in sequence via the venting bypass pipe and the third isolation device.

[0014] A further improvement of this utility model is that the dust collector unit also includes a metal compensator, and the first ash discharge valve includes an electric ash discharge valve and a pneumatic ash discharge valve. The output port of the conical ash hopper is connected in sequence to the electric ash discharge valve, the metal compensator and the first pneumatic ash discharge valve.

[0015] A further improvement of this utility model is that the first ash discharge valve also includes a manual slide gate valve, and the output port of the conical ash hopper is sequentially connected to the manual slide gate valve, the electric ash discharge valve, the metal compensator, and the first pneumatic ash discharge valve.

[0016] A further improvement of this utility model is that the second ash discharge valve is a second pneumatic ash discharge valve.

[0017] A further improvement of this utility model is that the nitrogen ash conveying device includes a first hopper pump and a second hopper pump arranged in parallel. The inlets of the first hopper pump and the second hopper pump are respectively connected to the outlet of the conical ash hopper via a second ash discharge valve, an intermediate ash hopper, and a first ash discharge valve. The outlets of the first hopper pump and the second hopper pump are respectively connected to the top inlet of the nitrogen-sealed ash silo.

[0018] A further improvement of this utility model is that: the gas distribution box includes a first gas distribution box and a second gas distribution box, which are symmetrically arranged outside the bag filter. The backflush pipes connected to the first gas distribution box and the second gas distribution box are arranged at intervals, and the nitrogen supply pipes of the first gas distribution box and the second gas distribution box are independently arranged.

[0019] A further improvement of this utility model is that the conical ash hopper has a conical inclination of at least 60°.

[0020] A further improvement of this utility model is that the diameter of the stainless steel metal filter bag is 130mm~160mm, the length of the stainless steel metal filter bag is ≤8m, and the distance between adjacent stainless steel metal filter bags is >220mm.

[0021] Compared with the prior art, the positive and progressive effects of this utility model are as follows:

[0022] This utility model provides a dry dust removal system for converter gas, employing high-temperature resistant stainless steel metal filter bags. These bags adapt to the operating conditions of converter gas, ensuring that the gas meets emission standards after dust removal. A nitrogen backflushing cleaning device, through a gas distribution box and backflushing pipe, safely cleans the stainless steel metal filter bags, preventing ferrous oxide dust from releasing heat upon contact with oxygen and reducing the risk of bag burning. The stainless steel metal filter bags have excellent conductivity, preventing static electricity generation. Furthermore, there are no ignition sources inside the dust collector, effectively preventing explosions. The nitrogen backflushing begins immediately after the oxygen blowing period, and the large amount of nitrogen backflushed into the dust collector also has a certain explosion-suppressing effect. An intermediate ash silo, combined with intermittent nitrogen ash conveying, completes the sealed transport of dust to the nitrogen-sealed ash silo during non-blowing periods, reducing nitrogen consumption. The entire system operates dry throughout, requiring no water conditioning. The inlet converter gas, after dust removal, achieves a dust concentration of <10mg / L. The emission concentration not only solves the problems of explosion risk, high energy consumption and inability to meet emission requirements when using the traditional LT method to remove dust from converter gas, but also has energy-saving benefits.

[0023] Furthermore, the dry dust removal system for converter gas also includes a first isolation device and a second isolation device, which can effectively isolate several parallel-connected dust collector units from other parts of the system, realize offline dust removal, improve safety performance, and facilitate rapid dust settling.

[0024] Furthermore, the dry dust removal system for converter gas also includes a venting bypass pipeline and a third isolation device. When the converter gas output from the converter system is substandard, the stainless steel metal filter bags can be protected by opening the third isolation device and closing the first and second isolation devices.

[0025] Furthermore, the adoption of a dual valve structure consisting of an electric ash discharge valve and a first pneumatic ash discharge valve increases the flexibility and reliability of ash discharge operations, allowing operators to adjust the ash discharge speed and volume according to actual conditions; the use of metal compensators can reduce maintenance costs caused by damage to pipelines and equipment due to high-temperature expansion.

[0026] Furthermore, the manual slide gate valve, electric ash discharge valve, and first pneumatic ash discharge valve form multiple isolation barriers. When maintenance is required, the manual slide gate valve, electric ash discharge valve, and first pneumatic ash discharge valve can be closed in sequence to ensure that the ash discharge system is effectively isolated from the maintenance area, preventing converter gas, dust, etc. from leaking into the maintenance area, providing a safe working environment for maintenance personnel, and avoiding safety accidents.

[0027] Furthermore, the second ash discharge valve adopts a pneumatic ash discharge valve, which has the characteristics of fast response speed and reliable operation. In an emergency, it can be quickly closed to prevent gas leakage or dust overflow.

[0028] Furthermore, the first and second silo pumps are connected in parallel, which can achieve alternating operation or maintenance standby. When operating alternately, the continuity of the ash conveying process can be guaranteed, thereby improving the ash conveying efficiency and meeting the needs of the converter gas dry dust removal system for rapid processing of large amounts of dust. When used as maintenance standby, when maintenance or repair of the silo pumps is required, the malfunctioning silo pump can be operated separately without stopping the entire ash conveying system.

[0029] Furthermore, the symmetrically arranged first and second gas distribution boxes, along with the backflush pipes spaced apart on them, enable the nitrogen backflush airflow to be distributed more evenly onto each stainless steel filter bag. During the cleaning process, this uniform distribution ensures that each filter bag receives a relatively consistent cleaning force, effectively removing dust adhering to the filter bag surface and preventing premature clogging or damage to some filter bags due to uneven cleaning. This improves the overall cleaning effect of the bag filter and ensures dust removal efficiency. Additionally, the first and second gas distribution boxes each have independent nitrogen supply pipes, allowing them to operate simultaneously during backflush. This enables rapid backflush removal of dust from the filter bag surface after the oxygen blowing period, preventing the heat released from the continued oxidation of ferrous oxide with oxygen during non-oxygen blowing periods from accumulating on the filter bag surface, which could burn the filter bags or shorten their lifespan. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the present invention and constitute a part of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0031] Figure 1 This is a front view of a dry dust removal system for converter gas according to the present invention.

[0032] Figure 2 This is a top view of the nitrogen backflushing cleaning device of this utility model;

[0033] Figure 3 This is an enlarged schematic diagram of the intermediate ash hopper of this utility model;

[0034] Figure 4 This is an enlarged schematic diagram of the nitrogen backflushing cleaning device of this utility model;

[0035] Figure 5 This is a schematic diagram of the overall structure of a dry dust removal system for converter gas according to the present invention.

[0036] Among them, 1 is a bag filter; 2 is a stainless steel metal filter bag; 3 is a nitrogen back-flushing cleaning device; 3-1 is a gas distribution box; 3-2 is a back-flushing pipe; 3-3 is a nozzle; 4 is an intermediate ash silo; 5 is a nitrogen ash conveying device; 6 is a dust-laden gas pipeline; 7 is a venting bypass pipeline; 8 is a clean gas pipeline; 9 is a nitrogen-sealed ash silo; 10 is a conical ash hopper; 11 is an electric ash discharge valve; 12 is a metal compensator; 13 is a first pneumatic ash discharge valve; 14 is a second ash discharge valve; 15 is a first isolation device; 16 is a second isolation device; and 17 is a third isolation device. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can typically be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of the embodiments of this utility model, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use, they are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the utility model. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This is an explanation of the present invention and not a limitation thereof.

[0043] See Figure 1 A dry dust removal system for converter gas includes a dust-laden gas pipeline 6, a clean gas pipeline 8, a nitrogen backflushing cleaning device 3, a nitrogen-sealed ash silo 9, and several parallel-connected dust collector units. Each dust collector unit includes a bag filter 1, a first ash discharge valve, an intermediate ash silo 4, a second ash discharge valve 14, and a nitrogen ash conveying device 5. The bag filter 1 includes, from bottom to top, a conical ash hopper 10, a cylindrical shell, and a head structure. Several stainless steel metal filter bags 2 are arranged in an array along the axial and longitudinal directions in the middle of the cylindrical shell.

[0044] See Figure 2 and Figure 4The nitrogen backflushing cleaning device 3 includes a gas distribution box 3-1 and several backflushing pipes 3-2 arranged axially along the stainless steel metal filter bags 2. The gas distribution box 3-1 is located outside the bag filter 1. One end of the backflushing pipe 3-2 is connected to the gas distribution box 3-1, and the other end passes through the columnar shell and is located above the stainless steel metal filter bags 2. Several nozzles 3-3 are provided on the backflushing pipe 3-2, and each nozzle 3-3 corresponds to a stainless steel metal filter bag 2. The output port of the conical ash hopper 10 is sequentially connected to the first ash discharge valve, the intermediate ash silo 4, the second ash discharge valve 14, and the input port of the nitrogen ash conveying device 5. The output port of the nitrogen ash conveying device 5 is connected to the top inlet of the nitrogen-sealed ash silo 9. The upper part of the columnar shell is the clean air chamber, and the lower part of the columnar shell is the dust gas chamber. The dust gas chamber is connected to the outlet of the dust-containing coal gas pipeline 6, and the clean air chamber is connected to the inlet of the clean coal gas pipeline 8.

[0045] During dust removal, the dry dust removal system is connected to the converter system, which includes a converter gas waste heat recovery device and a gas cooler connected in sequence; the inlet of the dust-laden gas pipeline 6 is connected to the converter gas waste heat recovery device, and the outlet of the clean gas pipeline 8 is connected to the gas cooler.

[0046] When the dry dust removal system is in dust collection mode: the dust-laden converter gas enters the dust chamber of the bag filter 1 through the dust-laden gas pipeline 6, and the dust in the converter gas is filtered by the stainless steel metal filter bags 2. The filtered clean gas enters the clean gas pipeline 8 from the clean gas chamber of the bag filter 1, and is stored in the gas holder after being cooled by the gas cooler. When the dry dust removal system is in reverse air cleaning mode: the gas distribution box 3-1 on the nitrogen reverse air cleaning device 3 uses the compressed nitrogen stored inside, and passes through the reverse air pipe 3-2 and nozzle 3-3. Dust adhering to the surface of the stainless steel metal filter bag 2 is blown off into the conical ash hopper 10 of the bag filter 1. When the dry dust removal system is unloading dust: when the dust in the conical ash hopper 10 accumulates to a preset height, the first ash discharge valve is opened and the second ash discharge valve 14 is closed, so that the dust falls into the intermediate ash silo 4. After the dust is unloaded, the first ash discharge valve is closed and the second ash discharge valve 14 is opened. The dust in the intermediate ash silo 4 enters the nitrogen ash conveying device 5 and is transported to the nitrogen-sealed ash silo 9 for storage under the action of compressed nitrogen.

[0047] This system uses high-temperature resistant stainless steel filter bags, adaptable to the operating conditions of converter gas, ensuring that the converter gas meets emission standards after dust removal via the stainless steel filter bags. The nitrogen backflushing cleaning device achieves safe cleaning of the stainless steel filter bags through a gas distribution box and backflushing pipe, preventing ferrous oxide dust from releasing heat upon contact with oxygen and reducing the risk of bag burning. The stainless steel filter bags have excellent conductivity and do not generate static electricity; furthermore, there are no ignition sources inside the dust collector, effectively preventing explosions. The nitrogen backflushing is initiated immediately after the oxygen blowing period, and the large amount of nitrogen backflushed into the dust collector also has a certain explosion-suppressing effect. The intermediate ash silo, combined with intermittent nitrogen ash conveying, completes the sealed dust transport to the nitrogen-sealed ash silo during non-blowing periods, reducing nitrogen consumption. The entire system operates dry, requiring no water conditioning, and the inlet converter gas achieves a dust level of <10mg / L after dust removal. The emission concentration not only solves the problems of explosion risk, high energy consumption and inability to meet emission requirements when using the traditional LT method to remove dust from converter gas, but also has energy-saving benefits.

[0048] Specifically, it also includes a first isolation device 15 and a second isolation device 16. The dust-laden gas chamber is connected to the outlet of the dust-laden gas pipeline 6 via the first isolation device 15, and the clean gas chamber is connected to the inlet of the clean gas pipeline 8 via the second isolation device 16. This effectively isolates several parallel-connected dust collector units from other parts of the system, enabling offline dust removal, improving safety performance, and facilitating rapid dust settling.

[0049] Specifically, it also includes a venting bypass pipe 7 and a third isolation device 17. The dust-laden gas pipe 6 is connected to the clean gas pipe 8 in sequence via the venting bypass pipe 7 and the third isolation device 17. When the converter gas output from the converter system is substandard, the stainless steel metal filter bag 2 can be protected by opening the third isolation device 17 and closing the first isolation device 15 and the second isolation device 16.

[0050] See Figure 3 Specifically, the dust collector unit also includes a metal compensator 12. The first ash discharge valve includes an electric ash discharge valve 11 and a pneumatic ash discharge valve. The output port of the conical ash hopper 10 is sequentially connected to the electric ash discharge valve 11, the metal compensator 12, and the first pneumatic ash discharge valve 13. The dual valve structure consisting of the electric ash discharge valve 11 and the first pneumatic ash discharge valve 13 increases the flexibility and reliability of the ash discharge operation, allowing operators to adjust the ash discharge speed and volume according to actual conditions. The use of the metal compensator 12 can reduce maintenance costs caused by damage to pipelines and equipment due to high-temperature expansion.

[0051] Specifically, the first ash discharge valve also includes a manual slide gate valve. The output port of the conical ash hopper 10 is sequentially connected to the manual slide gate valve, the electric ash discharge valve 11, the metal compensator 12, and the first pneumatic ash discharge valve 13. The manual slide gate valve, the electric ash discharge valve 11, and the first pneumatic ash discharge valve 13 form multiple isolation barriers. When maintenance is required, the manual slide gate valve, the electric ash discharge valve 11, and the first pneumatic ash discharge valve 13 can be closed sequentially to ensure effective isolation of the ash discharge system from the maintenance area, preventing converter gas, dust, etc. from leaking into the maintenance area, providing a safe working environment for maintenance personnel, and avoiding safety accidents.

[0052] Specifically, the second ash discharge valve 14 is a second pneumatic ash discharge valve. The pneumatic ash discharge valve has the characteristics of fast response and reliable operation. In an emergency, it can be quickly closed to prevent gas leakage or dust overflow.

[0053] Specifically, the nitrogen ash conveying device 5 includes a first hopper pump and a second hopper pump connected in parallel. The inlets of the first hopper pump and the second hopper pump are connected to the outlet of the conical ash hopper 10 via the second ash discharge valve 14, the intermediate ash hopper 4, and the first ash discharge valve, respectively. The outlets of the first hopper pump and the second hopper pump are connected to the top inlet of the nitrogen-sealed ash silo 9, respectively. The parallel connection of the first hopper pump and the second hopper pump allows for alternating operation or maintenance standby. When operating alternately, the continuity of the ash conveying process is ensured, thereby improving ash conveying efficiency and meeting the needs of the converter gas dry dust removal system for rapid processing of large amounts of dust. When used as a maintenance standby, if maintenance or repair of the hopper pump is required, the malfunctioning hopper pump can be operated individually without stopping the entire ash conveying system.

[0054] Specifically, the gas distribution box 3-1 includes a first gas distribution box and a second gas distribution box, symmetrically arranged outside the bag filter 1. Backflush pipes 3-2 connected to the first and second gas distribution boxes are spaced apart, and the nitrogen supply pipes for the first and second gas distribution boxes are independently configured. The symmetrical arrangement of the first and second gas distribution boxes, and the spaced-apart backflush pipes 3-2, allows for a more even distribution of the nitrogen backflush airflow onto each stainless steel filter bag 2. During the cleaning process, this uniform distribution ensures that each filter bag receives a relatively consistent cleaning force, effectively removing dust adhering to the filter bag surface and preventing premature clogging or damage to some filter bags due to uneven cleaning. This improves the overall cleaning effect of the bag filter 1 and ensures dust removal efficiency.

[0055] Specifically, the conical ash hopper 10 has a conical inclination of at least 60°; the stainless steel metal filter bag 2 has a diameter of 130mm to 160mm, a length of ≤8m, and a spacing of >220mm between adjacent stainless steel metal filter bags 2.

[0056] Example 1

[0057] See Figure 5 A dry dust removal system for converter gas includes a dust-laden gas pipeline 6, a clean gas pipeline 8, a nitrogen backflushing cleaning device 3, a nitrogen-sealed ash silo 9, and several parallel-connected dust collector units; the dust collector unit includes a bag filter 1, a first ash discharge valve, an intermediate ash silo 4, a second ash discharge valve 14, and a nitrogen ash conveying device 5.

[0058] The inlet of the dust-laden gas pipeline 6 of the dry dust removal system is connected to the converter gas waste heat recovery device. The outlet of the purified gas pipeline 8 is connected to the gas cooler. Temperature and gas moisture content detection instruments are installed at the inlet of the dust-laden gas pipeline 6. Qualified converter gas enters the bag filter 1 for filtration. After dust removal, it is sent to the gas cooler through the purified gas pipeline 8. Unqualified converter gas directly enters the vent bypass pipeline 7 and is sent to the gas vent pipeline of the converter system, and finally enters the plant area gas vent system.

[0059] The baghouse dust collector 1 has a circular tubular shell in the middle and a conical ash hopper at the bottom. The conical inclination must be greater than 60°. Stainless steel metal filter bags 2 are installed. A perforated plate divides the middle shell into a dust chamber and a clean air chamber. The area above the perforated plate is the clean air chamber, and the area below is the dust chamber. Dust-laden converter gas enters the baghouse dust collector 1 from above the ash hopper, is filtered by the stainless steel metal filter bags 2, and then enters the clean air chamber through the filter bag openings. The top of the clean air chamber is sealed with a conical or butterfly-shaped end cap structure, with an outlet pipe in the center. The end cap structure is connected to the tubular shell via a flange. Installing / removing the stainless steel metal filter bags requires removing the end cap structure. The ash hopper is equipped with... Equipped with a level gauge, and to ensure smooth ash discharge from the ash hopper, the outer shell of the ash hopper is also equipped with a vibrating motor, a dust fluidization device, an air cannon, and an anti-clogging air disc; the ash hopper outlet of the bag filter 1 is sequentially equipped with a manual slide gate valve, an electric ash discharge valve 11, a metal compensator 12, a first pneumatic ash discharge valve 13, an intermediate ash hopper 4, and a second pneumatic ash discharge valve. The volume of the intermediate ash hopper 4 is twice the amount of ash discharged in one backflushing cycle. The shell has a vent pipe. The manual slide gate valve, electric ash discharge valve 11, first pneumatic ash discharge valve 13, and second pneumatic ash discharge valve are all required to have zero leakage to ensure the airtightness of the entire dust removal system when discharging ash under negative pressure. An air inlet is provided above the ash hopper of the bag filter 1. A wear-resistant layer is provided on the cylinder opposite the air inlet. The air outlet is located at the top of the bag filter 1. An airflow distribution grid is installed 0.5 to 1m above the air inlet so that the dust-laden coal gas entering the bag filter 1 is evenly distributed on the surface of each stainless steel metal filter bag 2. Self-closing multi-stage explosion relief valves are installed in both the clean air chamber and the dust-laden gas chamber. The dust-laden converter gas enters from the dust-laden gas chamber, is filtered by the high-temperature resistant stainless steel metal filter bags 2, and the clean converter gas is discharged from the clean air chamber.

[0060] Stainless steel metal filter bags 2 are stainless steel metal filter bags arranged at fixed intervals and installed on the perforated plate. The number of stainless steel metal filter bags 2 in each bag dust collector 1 is adjusted according to the amount of dust-laden gas to be treated by the bag dust collector 1 and the size of the installation site. Stainless steel metal filter bags 2 are made of stainless steel metal powder or stainless steel metal wire mesh by pressing and sintering. It is a mature filter material available on the market. Its internal bag cage, bag mouth seal and bag bottom seal are all made of stainless steel, such as 304, 316 and 310S. It can withstand temperatures of 450℃~600℃ for a long time, which is sufficient to cope with the special working conditions of the converter gas temperature rising in a short time due to the failure of the upstream cooling waste heat recovery equipment. It can be selected according to the temperature and flue gas properties. The stainless steel metal filter bag 2 has a diameter between 130mm and 160mm and a maximum length of 8m. The longitudinal spacing of each stainless steel metal filter bag 2 is 200mm to 235mm, and the axial spacing is 200mm. Special sealing components are used to fix the stainless steel metal filter bag 2 to each mounting hole. When the length is greater than 6m, the bottom needs to be fixed to prevent the stainless steel metal filter bag 2 from shaking and causing wear between the filter bags. Since the stainless steel metal filter bag 2 is a rigid filter material, in order to avoid the mounting holes scratching the surface of the filter bag, when the diameter of the stainless steel metal filter bag 2 is 130mm, the diameter of the mounting hole is 140mm, and when the diameter of the metal membrane filter cartridge is 160mm, the diameter of the mounting hole is 170mm.

[0061] Since the main component of dust in converter gas is FeO, it is easily oxidized and releases heat when exposed to oxygen during non-blowing processes. Therefore, inert gas must be used to quickly backflush and clean the surface of the metal filter bags. The nitrogen backflushing cleaning device 3 is installed outside the bag filter 1. The backflushing pipe 3-2 from the gas distribution box 3-1 passes through the outer shell of the dust collection chamber and extends into the cylinder. The center of the nozzle 3-3 on the backflushing pipe 3-2 must be aligned with the center of the metal membrane filter cartridge. A manual ball valve is installed between the gas distribution box 3-1 and the backflushing pipe 3-2. During maintenance, the manual ball valve is closed to completely cut off the dust collection chamber from the outside and inside, ensuring safety. The nitrogen backflushing cleaning device 3 is equipped with 10 The large compressed nitrogen storage tanks and nitrogen delivery pipelines described above are designed to simultaneously backflush two bag filters 1, improving the cleaning speed and preventing the accumulation of ferrous oxide powder in the stainless steel filter bags 2, which could cause bag burning during non-blowing periods. The nitrogen backflushing cleaning device 3 is equipped with dual gas distribution boxes 3-1, located on both sides of a circular tubular shell. The matching backflushing pipes 3-2 enter the circular tubular shell from both sides. Each gas distribution box 3-1 operates independently and has its own independent air supply pipeline, enabling simultaneous backflushing. This doubles the efficiency of traditional backflushing cleaning devices and halves the backflushing time. The nitrogen ash conveying device 5 is installed at the bottom of the intermediate ash silo 4. The ash hopper of the bag filter 1 is equipped with dual silo pumps to improve the reliability of the ash conveying device. The ash inlet is equipped with a metal compensator 12 and an ash inlet swing valve. The silo pumps are used for ash conveying, and the ash outlet pipeline of the silo pump must be connected in parallel with the main conveying pipeline to ensure that maintenance of any silo pump will not affect the ash conveying of other silo pumps. The conveying gas source is oil-free and water-free compressed nitrogen.

[0062] Nitrogen-sealed ash silo 9 is a circular ash silo with a volume of 100. The nitrogen-sealed ash silo 9 is located at the lower part of the intermediate ash silo 4 and is equipped with a dual-fan configuration. A nitrogen blowing device is installed in the conical section of the nitrogen-sealed ash silo 9 to blow atmospheric pressure nitrogen into the nitrogen-sealed ash silo 9 through a low-pressure blower, so that the nitrogen-sealed ash silo 9 is filled with nitrogen and prevents the presence of oxygen in the nitrogen-sealed ash silo 9, which would cause the ferrous oxide to oxidize and release heat. The setup of the nitrogen-sealed ash silo 9 is crucial. The silo must be sealed with a slightly positive pressure nitrogen atmosphere to prevent air from entering. Room temperature nitrogen enters from the bottom of the silo and exits through the dust collector at the top. A pressure gauge is installed on the silo 9, and the gauge signal is interlocked with the nitrogen valve. When the pressure inside the silo is below +200 Pa, the valve is opened to allow room temperature nitrogen to enter; when the pressure exceeds +500 Pa, the valve is closed to reduce nitrogen consumption. The nitrogen-sealed ash silo 9 stores converter gas dust, which contains approximately 67% FeO. FeO readily oxidizes with air, releasing heat and raising the dust temperature. This temperature increase further exacerbates the oxidation of FeO. Since the silo cannot dissipate heat, the dust will spontaneously combust when the temperature reaches its ignition point. The nitrogen gas introduced into the nitrogen-sealed ash silo 9 is room temperature nitrogen gas. While sealing with nitrogen gas, it can also cool down the ash stored in the nitrogen-sealed ash silo 9. The ash outlet can be equipped with an electric ash discharge valve 11 and a humidifying and stirring ash discharge machine. The ash discharge is further cooled by spraying water. At room temperature, ferrous oxide reacts slowly with oxygen and will not release a large amount of heat.

[0063] The nitrogen ash conveying device 5 uses a silo pump for ash conveying. The gas source is nitrogen. Each bag filter 1 is equipped with a set of silo pumps. The dual-silo pump design allows for switching between them and serves as a backup for each other. Each device is equipped with an independent nitrogen storage tank.

[0064] It also includes a first isolation device 15 and a second isolation device 16. The dusty gas chamber is connected to the outlet of the dusty gas pipeline 6 via the first isolation device 15, and the clean gas chamber is connected to the inlet of the clean gas pipeline 8 via the second isolation device 16. Both the first isolation device 15 and the second isolation device 16 are gas isolation devices composed of an open blind flange valve and a triple-eccentric pneumatic butterfly valve, in accordance with the requirements of the "Safety Technical Specification for Gas Isolation Devices" AQ2048-2012. The valve types can be electric, pneumatic, electro-hydraulic, or hydraulic. The blind flange valve is normally open during operation and closed when disconnection from the system is required; the hard-seal butterfly valve opens during dust removal and closes during ash cleaning, enabling offline ash cleaning.

[0065] The dry dust removal system for converter gas also includes a venting bypass pipe 7 and a third isolation device 17. The dust-laden gas pipe 6 is connected to the clean gas pipe 8 via the venting bypass pipe 7 and the third isolation device 17. The opening and closing of the venting bypass pipe 7 is completed by the third isolation device 17. The venting bypass pipe 7 is interlocked with the front-end instruments of the dry dust removal system. The instruments are mainly flue gas moisture content detection instruments and temperature detection instruments. When the detection data exceeds the standard, the third isolation device 17 on the venting bypass pipe 7 opens, while the first isolation device 15 and the second isolation device 16 close. The converter gas that exceeds the standard no longer enters the dust collector unit, but is directly sent to the clean gas pipe 8 through the venting bypass pipe 7, and then enters the venting pipe of the main system for discharge. This can effectively protect the expensive stainless steel metal filter bag 2 from damage due to overheating or a large amount of water vapor (water vapor will cause the surface of the metal filter bag to clump and make it impossible to clean).

[0066] In steelmaking, converters are mainly divided into oxygen-blowing and non-oxygen-blowing periods. The oxygen-blowing period involves blowing oxygen into the molten iron in the converter, triggering a violent chemical reaction. The main chemical reactions include the oxidation of silicon, manganese, carbon, and phosphorus. For example, silicon reacts with oxygen to produce silicon dioxide (…). This process is highly exothermic and can significantly increase the temperature of the molten pool. Manganese oxidation produces manganese oxide (MnO), which, although releasing less heat, still contributes to the temperature rise. Carbon reacts with oxygen to produce carbon monoxide (CO), a reaction that is also exothermic and causes the molten steel to boil violently. Phosphorus is removed under high temperature and high alkalinity conditions, forming calcium phosphate and calcium sulfide, which become part of the slag. The carbon monoxide (CO) and flue gas from the oxygen blowing process are collected by the dust collection hood at the furnace mouth and, under the action of the induced draft fan, sequentially undergo coarse dust removal, high-temperature waste heat recovery, dry fine dust removal, and low-temperature waste heat recovery before being sent to the gas holder for storage.

[0067] The non-oxygen blowing period mainly refers to the process of adding molten iron and scrap steel to the converter, followed by tapping molten steel and cleaning slag. During this period, the converter opening will be away from the fume hood. The fume hood mainly collects ambient flue gas containing air. At this time, the amount of flue gas generated is small, the induced draft fan operates at low frequency, and the flue gas passes through coarse dust removal, high-temperature waste heat recovery, and dry fine dust removal in sequence. The purified flue gas is directly sent to the vent chimney for discharge through a three-way valve.

[0068] During operation, dust-laden converter gas or ambient flue gas, under the action of an induced draft fan, passes through a coarse dust removal gas-solid separator and a waste heat recovery fire-tube boiler before entering the dry dust removal system. It first enters the dust-laden gas chamber inside the bag filter 1 through the dust-laden gas pipeline 6 and the first isolation device 15. The dust is filtered out by stainless steel metal filter bags 2. The clean gas then enters the clean gas pipeline 8 from the clean gas chamber at the top of the bag filter 1 through the second isolation device 16. Finally, under the suction of the induced draft fan, it is cooled by the gas cooler and sent to the gas holder for storage. Ambient flue gas, after being filtered by the stainless steel metal filter bags 2 and meeting emission standards, is finally discharged into the atmosphere through the vent chimney.

[0069] When the converter oxygen blowing ends, the induced draft fan starts operating at a low frequency. At this time, the dust removal system receives a backflushing command and begins backflushing and cleaning the stainless steel metal filter bags 2. The nitrogen backflushing cleaning device 3 uses internally stored compressed nitrogen in the gas distribution box 3-1. By opening the electromagnetic pulse valve, the compressed nitrogen is quickly injected into the stainless steel metal filter bags 2 through the backflushing pipe 3-2 and nozzle 3-3, blowing the dust adhering to the surface of the stainless steel metal filter bags 2 into the conical ash hopper 10 at the bottom of the bag filter 1. The gas distribution box 3-1 adopts a first gas distribution box and a second gas distribution box symmetrically arranged outside the bag filter 1. Each has an independent nitrogen pipeline to supply compressed nitrogen, and the backflushing cleaning work can be started simultaneously. The efficiency is twice that of conventional cleaning devices, and the dust on the surface of the stainless steel metal filter bags 2 can be blown off quickly. During backflushing, in order to ensure that the blown-off dust falls smoothly into the conical dust hopper 10 at the bottom of the bag filter 1, the dust removal unit of the backflushing needs to be operated offline. Specifically, by closing the pneumatic butterfly valves on the first isolation device 15 and the second isolation device 16 of the unit, the bag filter 1 of the unit is disconnected from the entire dust removal system. The induced draft fan cannot generate suction force inside the dust removal unit, so the dust blown off will not be adsorbed back onto the surface of the stainless steel metal filter bag 2, which can effectively improve the efficiency of backflushing cleaning.

[0070] During ash discharge, when the dust accumulates to a certain height in the conical ash hopper 10, the first ash discharge valve is opened, and the electric ash discharge valve 11 is activated, allowing the dust to fall into the intermediate ash hopper 4. At this time, the second ash discharge valve 14 located at the bottom of the intermediate ash hopper 4 is closed. The electric ash discharge valve 11 controls the amount of dust entering the intermediate ash hopper 4 by the duration of its operation. After the first ash discharge valve closes, the electric ash discharge valve 11 stops operating simultaneously, and the second ash discharge valve 14 opens, allowing the dust to enter the nitrogen conveying device 5. Its outlet is connected to the first and second hopper pumps respectively through a three-way pipe. The inlets of the first and second hopper pumps are equipped with feed valves. After entering the first or second hopper pump, the dust is transported to the nitrogen-sealed ash silo 9 under the action of compressed nitrogen for storage, and periodically transported out by a suction and discharge vehicle. The nitrogen-sealed ash silo 9 is equipped with a pressure sensor, which controls the opening and closing of the nitrogen valve to maintain a slight positive pressure inside the nitrogen-sealed ash silo 9 at all times. The ash discharge operation is carried out after offline backflushing cleaning.

[0071] During fault venting: When the instrument detects that the temperature or moisture content of the dust-laden converter gas exceeds the set value, the automatic control system quickly opens the third isolation device 17 on the venting bypass pipe 7, and simultaneously closes the first isolation device 15 on the dust-laden gas pipe 6 and the second isolation device 16 on the clean gas pipe 8. This allows the gas with excessive temperature or moisture to pass directly through the clean gas pipe 8 and be discharged through the venting flare under the action of the fan, thereby preventing the overheated gas from damaging the stainless steel metal filter bag 2. The moisture-laden gas will combine with the dust on the surface of the stainless steel metal filter bag 2 and clump together, causing the dust to be unable to be blown off and clogging the filter bag.

[0072] Finally, it should be noted that the embodiments listed above are merely one or more specific manifestations of the technical solution of this utility model. Their purpose is to clearly illustrate the concept, principle, and application of this utility model through specific examples, and is by no means intended to limit the scope of protection of this utility model to these specific embodiments. In fact, the true value of this utility model lies in its proposed technical ideas and innovations, rather than its manifestations or implementation methods.

[0073] For those skilled in the art, after thoroughly reading and understanding the technical solution of this utility model, they are fully capable of making various changes, modifications, or equivalent substitutions to the specific embodiments of the utility model based on their own professional knowledge and skills. These changes may include, but are not limited to: adjusting the range of technical parameters, optimizing the algorithm flow to improve efficiency, and replacing some technical components to achieve better compatibility or reduce costs. As long as these modified technical solutions substantially retain the technical features claimed by the original utility model, that is, they can still achieve the core functions and effects of this utility model, then these changes should be considered to fall within the scope of protection of the pending claims of this utility model.

[0074] Furthermore, with the continuous progress and development of technology, new technical means and methods are constantly emerging, which provides ample space for the further improvement and perfection of this utility model. Therefore, the scope of protection of this utility model should also include reasonable and foresightful improvements and extensions based on existing technology. As long as these improvements and extensions do not deviate from the basic principles and core concept of this utility model, they should be regarded as equivalents of this utility model and are equally protected by patent rights.

Claims

1. A dry dedusting system for converter gas, characterized in that, It includes a dust-laden gas pipeline (6), a clean gas pipeline (8), a nitrogen backflushing cleaning device (3), a nitrogen-sealed ash silo (9), and several parallel dust collector units; the dust collector unit includes a bag filter (1), a first ash discharge valve, an intermediate ash silo (4), a second ash discharge valve (14), and a nitrogen ash conveying device (5); the bag filter (1) includes, from bottom to top, a conical ash hopper (10), a columnar shell and a head structure, and a number of stainless steel metal filter bags (2) arranged in an array along the axial and longitudinal directions in the middle of the columnar shell. The nitrogen backflushing cleaning device (3) includes a gas distribution box (3-1) and several backflushing pipes (3-2) arranged axially along the stainless steel metal filter bags (2). The gas distribution box (3-1) is located outside the bag filter (1). One end of the backflushing pipe (3-2) is connected to the gas distribution box (3-1), and the other end passes through the columnar shell and is located above the stainless steel metal filter bags (2). Several nozzles (3-3) are provided on the backflushing pipe (3-2). The nozzles (3-3) are connected to the stainless steel filter bags (2). Steel metal filter bags (2) are matched one-to-one; the output port of the conical ash hopper (10) is connected in sequence to the first ash discharge valve, the intermediate ash silo (4), the second ash discharge valve (14) and the input port of the nitrogen ash conveying device (5), and the output port of the nitrogen ash conveying device (5) is connected to the top inlet of the nitrogen-sealed ash silo (9); the upper part of the columnar shell is the clean air chamber and the lower part of the columnar shell is the dust gas chamber; the dust gas chamber is connected to the outlet of the dust-containing coal gas pipeline (6) and the clean air chamber is connected to the inlet of the clean coal gas pipeline (8); During dust removal, the dry dust removal system is connected to the converter system, which includes a converter gas waste heat recovery device and a gas cooler connected in sequence; the inlet of the dust-laden gas pipeline (6) is connected to the converter gas waste heat recovery device, and the outlet of the clean gas pipeline (8) is connected to the gas cooler.

2. A dry dust removal system for converter gas as claimed in claim 1, wherein, It also includes a first isolation device (15) and a second isolation device (16). The dust gas chamber is connected to the outlet of the dust-containing gas pipeline (6) via the first isolation device (15), and the clean gas chamber is connected to the inlet of the clean gas pipeline (8) via the second isolation device (16).

3. A dry dust removal system for converter gas as claimed in claim 2, wherein, It also includes a venting bypass pipe (7) and a third isolation device (17), and the dust-containing gas pipe (6) is connected to the clean gas pipe (8) in sequence via the venting bypass pipe (7) and the third isolation device (17).

4. A dry dust removal system for converter gas as claimed in claim 1, wherein The dust collector unit also includes a metal compensator (12), and the first ash discharge valve includes an electric ash discharge valve (11) and a pneumatic ash discharge valve. The outlet of the conical ash hopper (10) is connected in sequence to the electric ash discharge valve (11), the metal compensator (12) and the first pneumatic ash discharge valve (13).

5. A dry dust removal system for converter gas as claimed in claim 4, wherein, The first ash discharge valve also includes a manual slide gate valve. The output port of the conical ash hopper (10) is connected in sequence to the manual slide gate valve, the electric ash discharge valve (11), the metal compensator (12) and the first pneumatic ash discharge valve.

6. A dry dust removal system for converter gas as claimed in claim 1, wherein, The second ash discharge valve (14) is a second pneumatic ash discharge valve.

7. A dry dust removal system for converter gas according to claim 1, characterized in that, The nitrogen ash conveying device (5) includes a first hopper pump and a second hopper pump arranged in parallel. The inlets of the first hopper pump and the second hopper pump are respectively connected to the outlet of the conical ash hopper (10) via the second ash discharge valve (14), the intermediate ash hopper (4) and the first ash discharge valve. The outlets of the first hopper pump and the second hopper pump are respectively connected to the top inlet of the nitrogen-sealed ash silo (9).

8. A dry dust removal system for converter gas according to claim 1, characterized in that, The gas distribution box (3-1) includes a first gas distribution box (3-1) and a second gas distribution box (3-1), which are symmetrically arranged outside the bag filter (1). The backflush pipes (3-2) connected to the first gas distribution box (3-1) and the second gas distribution box (3-1) are spaced apart, and the nitrogen supply pipes of the first gas distribution box (3-1) and the second gas distribution box (3-1) are independently arranged.

9. A dry dust removal system for converter gas according to claim 1, characterized in that, The conical ash hopper (10) has a conical slope of at least 60°.

10. A dry dust removal system for converter gas according to claim 1, characterized in that, The stainless steel metal filter bag (2) has a diameter of 130mm~160mm, a length of ≤8m, an axial spacing of 200~220mm between adjacent stainless steel metal filter bags (2), and a longitudinal spacing of 200mm~235mm.

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