Converter flue gas dry dedusting system and method with spare fan switching mechanism

Abstract

The present application belongs to the technical field of metallurgical environmental protection equipment, and particularly relates to a converter flue gas dry dedusting system and method with a standby fan switching mechanism. The present application is composed of a standby fan switching mechanism and two parallel and identically-structured converter flue gas primary dedusting systems. Each converter flue gas primary dedusting system comprises, in sequence, a coal gas deduster, a variable frequency motor, a fan and a silencer; each fan is connected with a fan thin oil lubrication system, a fan bearing nitrogen sealing system and a fan thin oil station circulating cooling water system; and the standby fan switching mechanism is connected in parallel between the outlet of the coal gas deduster and the outlet of the silencer of each converter flue gas primary dedusting system. The present application effectively shortens the recovery time after the failure of the dedusting fan or the variable frequency motor (frequency converter), avoids the safety hazard of coal gas overflow in front of the converter in the abnormal operation state of the fan and the waste of converter coal gas resources, improves the on-site environment and improves the production efficiency of the steel enterprise.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical environmental protection equipment technology, specifically relating to a dry dust removal system and method for converter flue gas with a backup fan switching mechanism. Background Technology

[0002] The dry primary dust removal system for converter flue gas typically employs an axial flow fan with variable frequency speed control. This fan serves as the power source for the primary dust removal system, and its proper operation directly impacts the safety and dust removal efficiency of the entire system. Poor ventilation in the dust removal system can lead to flue gas overflowing from the furnace. Since the primary flue gas contains large amounts of flammable, explosive, and toxic gases such as CO, it poses a significant safety hazard to the furnace. Furthermore, when flue gas cannot be properly introduced into the dust removal system through the fan, the dust removal efficiency will be greatly reduced. A large amount of reusable converter gas will be emitted into the atmosphere through the vent chimney, causing air pollution and wasting valuable converter gas resources.

[0003] Currently, most steel companies in China do not have backup fan systems in their primary dry dust removal systems for converter flue gas. As the pace of smelting accelerates, higher demands are placed on the reliability of fans and variable frequency motors. If a fan or variable frequency motor (inverter) fails, the entire dust removal system will be unable to operate, forcing a shutdown of smelting. Because the airflow and pressure loss of each dust removal system vary across steel plants, axial flow fans are mostly custom-made products, resulting in long replacement cycles for parts. The maintenance and installation of fans and motors are also difficult, all of which seriously affect the resumption of smelting production. Summary of the Invention

[0004] This invention provides a dry dust removal system and method for converter flue gas with a backup fan switching mechanism. The purpose is to effectively shorten the recovery time after a failure of the dust removal fan or variable frequency motor (frequency converter), avoid the safety hazards of gas overflow in front of the furnace and the waste of converter gas resources caused by the fan in an abnormal operating state, thereby improving the on-site environment and increasing the production efficiency of steel enterprises.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A dry dust removal system for converter flue gas with a backup fan switching mechanism includes at least two parallel primary dust removal systems for converter flue gas, numbered 1 and 2. Each primary dust removal system has the same configuration, including a gas dust collector, a variable frequency motor, a fan, and a silencer. The variable frequency motor and the fan are connected sequentially between the gas dust collector and the silencer. Each fan is connected to a fan thin oil lubrication system, a fan bearing nitrogen sealing system, and a fan thin oil station circulating cooling water system. The system also includes a backup fan switching mechanism, which is connected in parallel between the outlet of the gas dust collector and the outlet of the silencer in each primary dust removal system for converter flue gas.

[0007] The backup fan switching mechanism includes a first transfer unit, a second transfer unit, a backup dust collector fan, a backup variable frequency motor, a backup silencer, a backup fan thin oil lubrication system, a backup fan bearing nitrogen sealing system, and a backup fan thin oil station circulating cooling water system. The first transfer unit is connected to the backup dust collector fan and the outlet of the gas dust collector in the two primary dust removal systems for converter flue gas. The second transfer unit is connected to the backup silencer and the outlet of the silencer in the two primary dust removal systems for converter flue gas. The backup dust collector fan is connected between the backup variable frequency motor and the backup silencer. The backup fan thin oil lubrication system, the backup fan bearing nitrogen sealing system, and the backup fan thin oil station circulating cooling water system are all connected to the backup dust collector fan.

[0008] It also includes a fan frequency converter; the fan frequency converter is connected to a standby frequency converter motor.

[0009] The first transfer unit includes a backup gas pipeline, four first transverse electric eye valves, four first metal expansion joints, and an eye valve platform. Two of the first metal expansion joints are connected to the outlet of each gas dust collector. Two of the first transverse electric eye valves are connected to the inlet side of the blower in each converter flue gas primary dust removal system. The other two first transverse electric eye valves are connected in series, and a T-junction is connected between them, which is connected to the backup dust removal blower. The other end of each of the two first transverse electric eye valves is connected to a first metal expansion joint, and the two first metal expansion joints are connected to the outlet of the gas dust collector in each converter flue gas primary dust removal system via the backup gas pipeline. The backup gas pipeline, the four first transverse electric eye valves, and the four first metal expansion joints are all connected to the eye valve platform.

[0010] It also includes a first maintenance manhole and an operating platform; the first maintenance manhole and operating platform are located next to the standby gas pipeline; the first maintenance manhole and operating platform are fixedly connected to the spectacle valve platform.

[0011] A set of steel inclined ladders is provided on each side of the aforementioned spectacle valve platform.

[0012] The second transfer unit includes four second transverse electric eye valves and two second metal expansion joints; two of the second transverse electric eye valves are respectively connected to the outlet of each silencer; the other two second transverse electric eye valves are connected in series, and a three-way pipe is connected between the two second transverse electric eye valves, which is connected to a spare silencer. The other end of each of the two second transverse electric eye valves is connected to a second metal expansion joint, and the two second metal expansion joints are respectively connected to the outlet of the second transverse electric eye valve on the silencer outlet pipe of each converter flue gas primary dust removal system.

[0013] It also includes a second maintenance manhole and an operating platform; the second maintenance manhole and operating platform are connected to the pipeline where the tee pipe is located.

[0014] The operating method of a converter flue gas dry dust removal system with a backup fan switching mechanism includes the following steps:

[0015] Step 1: Under normal smelting conditions, the standby fan switching mechanism is closed, and the first transverse electric eye valve at the fan inlet and the second transverse electric eye valve at the silencer outlet in the two parallel converter flue gas primary dust removal systems are both in the open and clamped state; the first transverse electric eye valve at both ends of the tee on the first transfer unit in the standby fan switching mechanism and the second transverse electric eye valve at both ends of the tee on the second transfer unit are both in the closed and clamped state.

[0016] Step Two: When the blower in the primary dust removal system of converter 1 or 2 malfunctions, the primary dust removal system of converter 1 or 2 will be interlocked and the furnace front lance will be raised, smelting will be interrupted, and at the same time, it will be urgently switched to the venting state. Nitrogen gas will be injected through the chimney to extract the primary flue gas from the pipelines and equipment of the dry dust removal system of converter flue gas, which is equipped with a backup blower switching mechanism. After the injection and replacement are completed, if the primary dust removal system of converter 1 malfunctions, proceed to Step Three; if the primary dust removal system of converter 2 malfunctions, proceed to Step Six.

[0017] Step 3: Close and clamp the first horizontal sliding electric eye valve at the inlet of the blower and the second horizontal sliding electric eye valve at the outlet of the silencer in the primary dust removal system of the No. 1 converter flue gas. At this time, the primary dust removal system of the No. 1 converter flue gas is isolated. Then, open and clamp the first horizontal sliding electric eye valve in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 1 converter flue gas and the tee, and open and clamp the second horizontal sliding electric eye valve in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 1 converter flue gas and the tee. Other equipment remains in its original state.

[0018] Step 4: After all the spectacle valves are in position and clamped, open the standby fan thin oil station circulating cooling water system, standby fan thin oil lubrication system and standby fan bearing nitrogen sealing system in the standby fan switching mechanism;

[0019] Step 5: After the standby fan thin oil station circulating cooling water system, standby fan thin oil lubrication system and standby fan bearing nitrogen sealing system are running stably, start the fan frequency converter in the standby fan switching mechanism to start the standby dust removal fan and put the standby dust removal fan in a low-speed operation state of 300 rpm, wait for the furnace front smelting resumption signal, and resume production after the furnace front preparation is completed.

[0020] Step Six: Close and clamp the first horizontal sliding electric eye valve at the inlet of the blower and the second horizontal sliding electric eye valve at the outlet of the silencer in the primary dust removal system of the No. 2 converter flue gas. At this time, the primary dust removal system of the No. 2 converter flue gas is isolated. Subsequently, open and clamp one of the first horizontal sliding electric eye valves in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 2 converter flue gas and the tee, and open and clamp one of the second horizontal sliding electric eye valves in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 2 converter flue gas and the tee. Other equipment remains in its original state.

[0021] Step 7: After all the spectacle valves are in position and clamped, open the standby fan thin oil station circulating cooling water system, standby fan thin oil lubrication system and standby fan bearing nitrogen sealing system in the standby fan switching mechanism;

[0022] Step 8: After the standby fan thin oil station circulating cooling water system, standby fan thin oil lubrication system and standby fan bearing nitrogen sealing system are running stably, start the fan frequency converter in the standby fan switching mechanism to start the standby dust removal fan and put the standby dust removal fan in a low-speed operation state of 300 rpm, wait for the furnace front smelting resumption signal, and resume production after the furnace front preparation is completed.

[0023] In step two, the completion of ejection and replacement means that there is no smoke or dust in front of the furnace and the CO concentration is less than 24 ppm as detected.

[0024] Beneficial effects:

[0025] (1) This invention is organically composed of a standby fan switching mechanism and two parallel and identical converter flue gas primary dust removal systems. When any main fan in either of the two converter flue gas primary dust removal systems fails or needs maintenance, production can be resumed shortly after shutdown by switching to the standby fan switching mechanism. This invention can effectively shorten the restart time after a failure of the dust removal fan or variable frequency motor (frequency converter), avoid the safety hazard of gas overflow in front of the furnace and the waste of converter gas resources caused by the fan operating under abnormal conditions, improve the on-site environment, and increase the production efficiency of steel enterprises.

[0026] (2) The metal expansion joint in this invention effectively compensates for the pipe elongation caused by hot flue gas.

[0027] (3) The present invention is equipped with a fan frequency converter for starting, stopping and speed regulation of the fan frequency converter motor, so that the present invention can adapt to the state of the primary flue gas of the converter changing with the smelting rhythm, thus saving electricity.

[0028] (4) The first inspection manhole and operating platform and the second inspection manhole and operating platform in this invention make the inspection and maintenance of this invention more convenient.

[0029] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the construction process of the present invention.

[0032] Figure 2 This is a top view of the structure of the present invention.

[0033] Figure 3 This is a front view of the present invention.

[0034] Figure 4 This is a side view of the present invention.

[0035] Figure 5 yes Figure 2 A schematic diagram of the AA section.

[0036] Figure 6 This is a schematic diagram of the normal state of the present invention.

[0037] Figure 7 This is a schematic diagram of the primary dust removal system for the No. 1 converter flue gas during maintenance in this invention.

[0038] Figure 8 This is a schematic diagram of the primary dust removal system for converter No. 2 under maintenance in this invention.

[0039] In the diagram: 1. Backup gas pipeline; 2. Backup dust collector fan; 3. Backup variable frequency motor; 4. Backup silencer; 5. First horizontal sliding electric eye valve; 6. First metal expansion joint; 7. Eye valve platform; 8. First maintenance manhole and operating platform; 9. Fan variable frequency drive; 10. Backup fan thin oil lubrication system; 11. Backup fan bearing nitrogen sealing system; 12. Backup fan thin oil station circulating cooling water system; 13. Gas dust collector; 14. Variable frequency motor; 15. Fan; 16. Silencer; 17. Second horizontal sliding electric eye valve; 18. Second metal expansion joint; 19. Second maintenance manhole and operating platform. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1:

[0042] according to Figures 1-8 The converter flue gas dry dust removal system shown includes at least two parallel converter flue gas primary dust removal systems, numbered 1 and 2. Each primary dust removal system has the same configuration, including a gas dust collector 13, a variable frequency motor 14, a fan 15, and a silencer 16. The variable frequency motor 14 and the fan 15 are connected sequentially between the gas dust collector 13 and the silencer 16. Each fan 15 is connected to a fan thin oil lubrication system, a fan bearing nitrogen sealing system, and a fan thin oil station circulating cooling water system. The system also includes a backup fan switching mechanism, which is connected in parallel between the outlet of the gas dust collector 13 and the outlet of the silencer 16 in each primary dust removal system.

[0043] In actual use, when smelting is under normal conditions, the standby fan switching mechanism is closed, and the primary flue gas from the two converters operates independently through two parallel primary dust removal systems. When fan 15 in either converter 1 or 2's primary dust removal system malfunctions, the system interlocks, shutting off the smelting process and simultaneously switching to venting mode. Nitrogen gas is injected through the chimney to extract the primary flue gas from the pipelines and equipment of the dry dust removal system equipped with the standby fan switching mechanism. Once injection and replacement are complete, i.e., after the CO concentration is detected to be less than 24 ppm, the standby fan switching mechanism blocks the fan in the malfunctioning converter 1 or 2 primary dust removal system. The flue gas that was originally transported through the fan in the malfunctioning converter 1 or 2 primary dust removal system is now transported through the standby fan switching mechanism.

[0044] By adopting the technical solution of this invention, the time to resume production after the failure of dust removal fan or variable frequency motor (frequency converter) is effectively shortened, the safety hazards of gas overflow in front of the furnace and the waste of converter gas resources caused by the fan in abnormal operation are avoided, the on-site environment is improved, and the production efficiency of steel enterprises is increased.

[0045] Example 2:

[0046] according to Figures 1-8The dry dust removal system for converter flue gas shown, with a backup fan switching mechanism, differs from Embodiment 1 in that: the backup fan switching mechanism includes a first switching unit, a second switching unit, a backup dust removal fan 2, a backup variable frequency motor 3, a backup silencer 4, a backup fan thin oil lubrication system 10, a backup fan bearing nitrogen sealing system 11, and a backup fan thin oil station circulating cooling water system 12; the first switching unit is connected to the backup dust removal fan 2 and the outlet of the gas dust collector 13 in the two primary dust removal systems for converter flue gas; the second switching unit is connected to the backup silencer 4 and the outlet of the silencer 16 in the two primary dust removal systems for converter flue gas; the backup dust removal fan 2 is connected between the backup variable frequency motor 3 and the backup silencer 4; the backup fan thin oil lubrication system 10, the backup fan bearing nitrogen sealing system 11, and the backup fan thin oil station circulating cooling water system 12 are all connected to the backup dust removal fan 2.

[0047] In actual use, when smelting is under normal conditions, the standby fan switching mechanism is closed, and the primary flue gas from the two converters operates independently through two parallel primary dust removal systems. When fan 15 in the primary dust removal system of converter 1 or 2 malfunctions, the primary dust removal system of converter 1 or 2 is interlocked, the furnace front nozzle is raised, smelting is interrupted, and an emergency switch to venting mode is initiated. Nitrogen gas is injected through the chimney to extract the primary flue gas from the pipelines and equipment of the dry dust removal system of converter flue gas equipped with the standby fan switching mechanism. When the injection and replacement are completed, i.e., there is no dust in front of the furnace and the CO concentration is less than 24 ppm, the standby fan switching mechanism blocks fan 15 in the malfunctioning primary dust removal system of converter 1 or 2. The flue gas that originally needed to be transported through the malfunctioning fan of the primary dust removal system of converter 1 or 2 is discharged after passing through the first transfer unit, the standby variable frequency motor 3, the standby dust removal fan 2, the standby silencer 4, and the second transfer unit.

[0048] In practical applications, since most dust collector fans are axial flow fans, their front and rear shafts are equipped with rolling bearings. Due to the high fan speed (typically 300-1800 rpm), the bearing temperature rises significantly, requiring a dedicated lubrication system. The standby fan thin oil lubrication system 10 is used for the lubrication and cooling of the front and rear bearings of the standby dust collector fan 2. The standby fan bearing nitrogen sealing system 11 creates a slight positive pressure in the bearing housing by introducing low-pressure nitrogen. Since the flue gas contains flammable and explosive components, the nitrogen sealing gas plays a safety protection role in preventing flue gas from leaking out of the shaft clearance, while also cooling the cooling wheel at the fan shaft end. The standby fan thin oil station circulating cooling water system 12 connects the circulating cooling water to the plate heat exchanger integrated with the standby fan thin oil lubrication system 10 to cool the thin oil (46# turbine oil).

[0049] The low-pressure nitrogen and circulating cooling water used in the standby fan bearing nitrogen sealing system 11 and the standby fan thin oil station circulating cooling water system 12 in the standby fan switching system are connected in parallel with the fan bearing nitrogen sealing system and the fan thin oil station circulating cooling water system of the two converter flue gas primary dust removal systems, and share the same energy medium main pipe. This not only saves costs, but also reduces the space occupied by the system.

[0050] The standby fan thin oil lubrication system 10, the standby fan bearing nitrogen sealing system 11, and the standby fan thin oil station circulating cooling water system 12 used in this embodiment are existing technologies and have the same structure as the fan thin oil lubrication system, fan bearing nitrogen sealing system, and fan thin oil station circulating cooling water system in the two converter flue gas primary dust removal systems.

[0051] Example 3:

[0052] according to Figure 1 The converter flue gas dry dust removal system with a backup fan switching mechanism shown differs from Embodiment 2 in that it also includes a fan frequency converter 9; the fan frequency converter 9 is connected to the backup frequency converter motor 3.

[0053] In actual use, the fan frequency converter 9 is connected to the standby variable frequency motor 3 via a cable. Since the primary flue gas of the converter changes continuously with the smelting rhythm, in order to adapt to this working condition and to save electricity, the present invention uses the fan frequency converter 9 to control the start, stop and speed of the standby variable frequency motor 3 installed at the drive end of the standby dust removal fan, thereby realizing variable frequency control of the standby dust removal fan 2.

[0054] Example 4:

[0055] according to Figures 1-8 The converter flue gas dry dust removal system with a backup fan switching mechanism shown differs from Embodiment 2 in that: the first switching unit includes a backup gas pipeline 1, four first transverse electric eye valves 5, four first metal expansion joints 6, and an eye valve platform 7; two of the first metal expansion joints 6 are respectively connected to the outlet of each gas dust collector 13; two of the first transverse electric eye valves 5 are respectively connected to the inlet side of the fan 15 in each converter flue gas primary dust removal system; the other two first transverse electric eye valves 5 are connected in series, and a three-way pipe is connected between these two first transverse electric eye valves 5, which is connected to the backup dust removal fan 2; the other end of each of the two first transverse electric eye valves 5 is connected to a first metal expansion joint 6, and the two first metal expansion joints 6 are respectively connected to the outlet of the gas dust collector 13 in each converter flue gas primary dust removal system through the backup gas pipeline 1; the backup gas pipeline 1, the four first transverse electric eye valves 5, and the four first metal expansion joints 6 are all connected to the eye valve platform 7.

[0056] In actual use, when smelting is under normal conditions, the first horizontal sliding electric eye valve 5 at the inlet side of the blower 15 in each converter flue gas primary dust removal system and the second horizontal sliding electric eye valve 17 at the outlet of the silencer 16 in each converter flue gas primary dust removal system are opened and clamped, while the remaining first horizontal sliding electric eye valves 5 and second horizontal sliding electric eye valves 17 are closed and clamped. The primary flue gas from the two converters runs through two parallel converter flue gas primary dust removal systems and is purified by their respective gas dust collectors 13 before being discharged. When the blower 15 in the No. 1 converter flue gas primary dust removal system fails, the No. 1 converter primary dust removal system interlocks and the furnace front gun is brought forward, smelting is interrupted, and at the same time, it is urgently switched to the venting state. Nitrogen gas is injected through the chimney to extract the primary flue gas from the converter flue gas dry dust removal system pipelines and equipment equipped with a backup blower switching mechanism. Once the injection and replacement processes are complete, i.e., there is no smoke or dust in front of the furnace and the CO concentration is less than 24 ppm, the standby fan switching mechanism shuts off the primary dust removal system of converter 1 by closing the first horizontal-moving electric eye valve 5 located at the inlet side of fan 15 in the primary dust removal system of converter 1. This allows the flue gas from the gas dust collector 13 in the primary dust removal system of converter 1 to pass through the standby gas pipeline 1, the standby dust removal fan 2, the standby silencer 4, and the second transfer unit before being discharged from the outlet of the primary dust removal system of converter 1. When the primary dust removal system of converter 2 malfunctions, the primary dust removal system of converter 2 is interlocked, the furnace front lance is brought forward, smelting is interrupted, and an emergency switch to venting mode is initiated. Nitrogen gas is injected through the chimney to extract the primary flue gas from the pipelines and equipment of the dry dust removal system of converter flue gas equipped with the standby fan switching mechanism. Once the ejection and replacement are completed, i.e. there is no smoke or dust in front of the furnace and the CO concentration is less than 24 ppm, the standby fan switching mechanism shuts off the fan 15 in the primary dust removal system of converter 2 by closing the first horizontal electric eye valve 5 at the inlet side of the fan 15. This allows the flue gas from the gas dust collector 13 in the primary dust removal system of converter 2 to pass through the standby gas pipeline 1, the standby dust removal fan 2, the standby silencer 4, and the second transfer unit before being discharged from the outlet of the primary dust removal system of converter 2.

[0057] In this embodiment, four first metal expansion joints 6 are provided. The purpose of providing one first metal expansion joint 6 at the outlet of each gas dust collector 13 is to eliminate the pipe expansion caused by hot flue gas and the axial thrust generated by the pipe expansion. This prevents the thrust from directly acting on the valve plate of the first transverse electric eye valve 5, causing deformation and damage to the valve plate, thus avoiding affecting the operation and reliability of the eye valve due to valve plate deformation or damage. The other two first metal expansion joints 6 are also provided to prevent the axial force of the pipe from directly acting on the valve plate of the first transverse electric eye valve 5, and to release the thermal expansion and contraction of the gas dust collector after cooling, preventing the weld seam at the dust collector outlet from cracking and ensuring system safety.

[0058] In this embodiment, the installation positions of the four first transverse electric eye valves 5 are at the same elevation as the center line of the gas dust collector 13. The length of the eye valve platform 7 runs through the inlet pipes of three fans: the fan 15 in the two converter flue gas primary dust removal systems and the standby dust removal fan 2 in the standby fan switching mechanism. It is independently supported.

[0059] Example 5:

[0060] according to Figure 1 , Figure 2 and Figure 5 The converter flue gas dry dust removal system with a backup fan switching mechanism shown differs from Embodiment 4 in that it also includes a first maintenance manhole and an operating platform 8; the first maintenance manhole and operating platform 8 are located next to the backup gas pipeline 1; the first maintenance manhole and operating platform 8 are fixedly connected to the spectacle valve platform 7.

[0061] In actual use, the installation of the first maintenance manhole and operating platform 8 facilitates maintenance and ensures the safety of operators.

[0062] Example 6:

[0063] according to Figures 1-5 The converter flue gas dry dust removal system with a backup fan switching mechanism shown differs from Embodiment 4 or Embodiment 5 in that a set of steel inclined ladders is provided on both sides of the spectacle valve platform 7.

[0064] In practical use, the inclined ladder makes it easier for operators to go up and down, and also ensures their safety.

[0065] Example 7:

[0066] according to Figures 1-3 , Figures 5-8 The converter flue gas dry dust removal system with a backup fan switching mechanism shown differs from Embodiment 2 in that: the second transfer unit includes four second transverse electric eye valves 17 and two second metal expansion joints 18; two of the second transverse electric eye valves 17 are respectively connected to the outlet of each silencer 16; the other two second transverse electric eye valves 17 are connected in series, and a three-way pipe is connected between the two second transverse electric eye valves 17, which is connected to the backup silencer 4 through the three-way pipe. The other end of the two second transverse electric eye valves 17 is respectively connected to a second metal expansion joint 18, and the two second metal expansion joints 18 are respectively connected to the outlet of the gas dust collector 13 in each converter flue gas primary dust removal system.

[0067] In actual use, when smelting is under normal conditions, the second transfer unit is not working, and each converter flue gas primary dust removal system normally discharges the flue gas. When the No. 1 converter flue gas primary dust removal system malfunctions, the No. 1 converter primary dust removal system interlocks and the furnace front gun is brought forward, smelting is interrupted, and at the same time, it is urgently switched to the venting state. Nitrogen gas is injected through the chimney to extract the converter primary flue gas from the pipelines and equipment of the converter flue gas dry dust removal system equipped with a backup fan switching mechanism. Once the injection and replacement processes are complete, i.e., there is no smoke or dust in front of the furnace and the CO concentration is less than 24 ppm, the standby fan switching mechanism shuts off the primary dust removal system of converter 1 by closing the first horizontal-moving electric eye valve 5 located at the inlet side of fan 15 in the primary dust removal system of converter 1. This allows the flue gas from the gas dust collector 13 in the primary dust removal system of converter 1 to pass through the standby gas pipeline 1, the standby dust removal fan 2, the standby silencer 4, the second horizontal-moving electric eye valve 17 connected to the primary dust removal system of converter 1 in the second transfer unit, and the second metal expansion joint 18, before being discharged from the outlet of the primary dust removal system of converter 1. When the primary dust removal system of converter 2 malfunctions, the primary dust removal system of converter 2 is interlocked, the furnace front lance is brought forward, smelting is interrupted, and an emergency switch to venting mode is initiated. Nitrogen gas is injected through the chimney to extract the primary flue gas from the converter primary flue gas in the pipelines and equipment of the dry dust removal system of converter flue gas equipped with the standby fan switching mechanism. Once the ejection and replacement are completed, i.e. there is no smoke or dust in front of the furnace and the CO concentration is less than 24 ppm, the standby fan switching mechanism closes the first horizontal sliding electric eye valve 5 located on the inlet side of the variable frequency motor 14 in the primary dust removal system of converter 2, thus blocking the primary dust removal system of converter 2. This allows the flue gas from the gas dust collector 13 in the primary dust removal system of converter 2 to pass through the standby gas pipeline 1, the standby dust removal fan 2, the standby silencer 4, the second horizontal sliding electric eye valve 17 connected to the primary dust removal system of converter 2 in the second transfer unit, and the second metal expansion joint 18, before being discharged from the outlet of the primary dust removal system of converter 2.

[0068] Example 8:

[0069] according to Figures 1-8 The converter flue gas dry dust removal system with a backup fan switching mechanism shown differs from Embodiment 7 in that it also includes a second maintenance manhole and operating platform 19; the second maintenance manhole and operating platform 19 are connected to the pipeline where the tee pipe is located.

[0070] In actual use, the second maintenance manhole and operating platform 19 facilitate maintenance and ensure the safety of operators.

[0071] Example 9:

[0072] Reference Figures 1-8The working method of a converter flue gas dry dust removal system with a backup fan switching mechanism includes the following steps:

[0073] Step 1: Under normal smelting conditions, the standby fan switching mechanism is closed. The first transverse electric eye valve 5 at the inlet of the fan 15 and the second transverse electric eye valve 17 at the outlet of the silencer 16 in the two parallel converter flue gas primary dust removal systems are both in the open and clamped state; the first transverse electric eye valve 5 at both ends of the tee on the first transfer unit in the standby fan switching mechanism and the second transverse electric eye valve 17 at both ends of the tee on the second transfer unit are both in the closed and clamped state.

[0074] Step Two: When fan 15 in the primary dust removal system of converter 1 or 2 malfunctions, the primary dust removal system of converter 1 or 2 will be interlocked, the furnace front lance will be raised, smelting will be interrupted, and at the same time, it will be urgently switched to the venting state. Nitrogen gas will be injected through the chimney to extract the primary flue gas from the pipelines and equipment of the dry dust removal system of converter flue gas, which is equipped with a backup fan switching mechanism. After the injection and replacement are completed, if the fan in the primary dust removal system of converter 1 malfunctions, proceed to Step Three; if the fan in the primary dust removal system of converter 2 malfunctions, proceed to Step Six.

[0075] Step 3: Close and clamp the first horizontal sliding electric valve 5 at the inlet of fan 15 and the second horizontal sliding electric valve 17 at the outlet of silencer 16 in the primary dust removal system of converter 1. At this time, the primary dust removal system of converter 1 is isolated. Then, open and clamp one of the first horizontal sliding electric valves 5 in the standby fan switching mechanism that is connected to the primary dust removal system of converter 1 and the tee, and open and clamp one of the second horizontal sliding electric valves 17 in the standby fan switching mechanism that is connected to the primary dust removal system of converter 1 and the tee. Other equipment remains in its original state.

[0076] Step 4: After all the spectacle valves are in position and clamped, open the standby fan thin oil station circulating cooling water system 12, the standby fan thin oil lubrication system 10 and the standby fan bearing nitrogen sealing system 11 in the standby fan switching mechanism;

[0077] Step 5: After the standby fan thin oil station circulating cooling water system 12, the standby fan thin oil lubrication system 10 and the standby fan bearing nitrogen sealing system 11 are running stably, start the fan frequency converter 9 in the standby fan switching mechanism, thereby starting the standby dust removal fan 2, so that the standby dust removal fan 2 is running at a low speed of 300 rpm, and wait for the furnace front smelting to resume signal. After the furnace front preparation is completed, production can be resumed.

[0078] Step Six: Close and clamp the first horizontal sliding electric eye valve 5 at the inlet of the blower 15 and the second horizontal sliding electric eye valve 17 at the outlet of the silencer 16 in the primary dust removal system of the No. 2 converter flue gas. At this time, the primary dust removal system of the No. 2 converter flue gas is isolated. Subsequently, open and clamp the first horizontal sliding electric eye valve 5 in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 2 converter flue gas and the tee, and open and clamp the second horizontal sliding electric eye valve 17 in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 2 converter flue gas and the tee. Other equipment remains in its original state.

[0079] Step 7: After all the spectacle valves are in position and clamped, open the standby fan thin oil station circulating cooling water system 12, the standby fan thin oil lubrication system 10 and the standby fan bearing nitrogen sealing system 11 in the standby fan switching mechanism;

[0080] Step 8: After the standby fan thin oil station circulating cooling water system 12, the standby fan thin oil lubrication system 10, and the standby fan bearing nitrogen sealing system 11 are running stably, start the fan frequency converter 9 in the standby fan switching mechanism, thereby starting the standby dust removal fan 2, so that the standby dust removal fan 2 is running at a low speed of 300 rpm, waiting for the furnace front smelting to resume signal. Production can be resumed after the furnace front preparation is completed.

[0081] Furthermore, in step two, the completion of ejection and replacement means that there is no smoke or dust in front of the furnace and the CO concentration is less than 24 ppm as detected.

[0082] This invention effectively shortens the recovery time after a dust removal fan or variable frequency motor (frequency converter) failure, avoids the safety hazard of gas overflow in front of the furnace and the waste of converter gas resources caused by the fan operating under abnormal conditions, improves the on-site environment, and increases the production efficiency of steel enterprises.

[0083] In this implementation, the selection and arrangement of the backup dust removal fan 2, backup variable frequency motor 3, and backup silencer 4 in the backup fan switching mechanism are completely consistent with the fans, motors, and silencers of the two parallel converter flue gas primary dust removal systems No. 1 and No. 2, and the distance from the path of the two converter flue gas primary dust removal systems is consistent. This ensures that the two converter flue gas primary dust removal systems have consistent air pressure after switching the backup fan switching mechanism, and will not compete for air when the two systems finally enter the clean gas main pipe.

[0084] In practical applications, each sliding electric spectacle valve has different pressure-bearing capacities on both sides of its valve plate, with separate high-pressure and low-pressure sides. In this embodiment, since the dust collector fan is an induced draft fan, the negative pressure is greater closer to the fan inlet and the positive pressure is greater closer to the fan outlet. When one of the three fans is under maintenance, the sliding electric spectacle valves on both sides are closed. Therefore, the sides facing away from the inlet and outlet of that fan are the high-pressure sides of the electric spectacle valves. Figures 6-8 As shown.

[0085] Where there is no conflict, those skilled in the art can combine the relevant technical features in the above examples according to the actual situation to achieve the corresponding technical effects. Specific details of the various combinations will not be elaborated here.

[0086] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0087] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0088] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Any simple modifications, equivalent variations, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the present invention.

Claims

1. A dry dust removal system for converter flue gas with a backup fan switching mechanism, comprising at least two parallel primary dust removal systems for converter flue gas, number 1 and number 2, each having the same configuration, including a gas dust collector (13), a variable frequency motor (14), a fan (15), and a silencer (16); the variable frequency motor (14) and the fan (15) are sequentially connected between the gas dust collector (13) and the silencer (16); each fan (15) is connected to a fan thin oil lubrication system, a fan bearing nitrogen sealing system, and a fan thin oil station circulating cooling water system; characterized in that: It also includes a backup fan switching mechanism; the backup fan switching mechanism is connected in parallel between the outlet of the gas dust collector (13) and the outlet of the silencer (16) of each converter flue gas primary dust removal system, and is used to replace the faulty fan by switching the pipeline when the fan of any dust removal system fails. The standby fan switching mechanism includes a first switching unit, a second switching unit, a standby dust removal fan (2), a standby variable frequency motor (3), a standby silencer (4), a standby fan thin oil lubrication system (10), a standby fan bearing nitrogen sealing system (11), and a standby fan thin oil station circulating cooling water system (12). The first switching unit is connected to the outlet of the standby dust removal fan (2) and the gas dust collector (13) in the two primary dust removal systems of converter flue gas. The second switching unit is connected to the outlet of the standby silencer (4) and the silencer (16) in the two primary dust removal systems of converter flue gas. The standby dust removal fan (2) is connected between the standby variable frequency motor (3) and the standby silencer (4). The standby fan thin oil lubrication system (10), the standby fan bearing nitrogen sealing system (11), and the standby fan thin oil station circulating cooling water system (12) are connected to the standby dust removal fan (2). The first transfer unit includes a spare gas pipeline (1), four first transverse electric eye valves (5), four first metal expansion joints (6), and an eye valve platform (7); two of the first metal expansion joints (6) are respectively connected to the outlet of each gas dust collector (13); two of the first transverse electric eye valves (5) are respectively connected to the inlet side of the blower (15) in each converter flue gas primary dust removal system; the other two first transverse electric eye valves (5) are connected in series, and these two first transverse electric eye valves (5) A three-way pipe is connected between the two first transverse electric eye valves (5) and the second one is connected to the standby dust removal fan (2). The other end of each of the two first transverse electric eye valves (5) is connected to a first metal expansion joint (6). The two first metal expansion joints (6) are connected to the outlet of the gas dust collector (13) of each converter flue gas primary dust removal system through the standby gas pipeline (1). The standby gas pipeline (1), the four first transverse electric eye valves (5) and the four first metal expansion joints (6) are all connected to the eye valve platform (7). The second transfer unit includes four second transverse electric eye valves (17) and two second metal expansion joints (18); two of the second transverse electric eye valves (17) are respectively connected to the outlet of each silencer (16); the other two second transverse electric eye valves (17) are connected in series, and a three-way pipe is connected between the two second transverse electric eye valves (17), which is connected to the spare silencer (4). The other end of the two second transverse electric eye valves (17) is respectively connected to a second metal expansion joint (18), and the two second metal expansion joints (18) are respectively connected to the outlet of the second transverse electric eye valve (17) on the outlet pipe of the silencer (16) in each converter flue gas primary dust removal system.

2. The dry scrubber system with a backup fan switching mechanism for a converter as claimed in claim 1, wherein: It also includes a fan frequency converter (9); the fan frequency converter (9) is connected to a standby frequency converter motor (3).

3. The dry scrubber system with a backup fan switching mechanism for a converter as claimed in claim 1, wherein: It also includes a first maintenance manhole and operating platform (8); the first maintenance manhole and operating platform (8) is located next to the standby gas pipeline (1); the first maintenance manhole and operating platform (8) is fixedly connected to the spectacle valve platform (7).

4. The dry scrubber system with a backup fan switching mechanism for a converter as claimed in claim 1 or 3, wherein: A set of steel inclined ladders is provided on both sides of the eyeglass valve platform (7).

5. The dry scrubber system with a backup fan switching mechanism for a converter as claimed in claim 1, wherein: It also includes a second maintenance manhole and operating platform (19); the second maintenance manhole and operating platform (19) are connected to the pipeline where the tee pipe is located.

6. A method of operating a converter off-gas dry dust collection system with a back-up fan switching mechanism, characterized by: The converter flue gas dry dust removal system with a backup fan switching mechanism as described in any one of claims 1-5 includes the following steps: Step 1: Under normal smelting conditions, the standby fan switching mechanism is closed. The first horizontal sliding electric eye valve (5) at the inlet of the fan (15) and the second horizontal sliding electric eye valve (17) at the outlet of the silencer (16) in the two parallel converter flue gas primary dust removal systems are both in the open and clamped state; the first horizontal sliding electric eye valve (5) at both ends of the tee on the first transfer unit in the standby fan switching mechanism and the second horizontal sliding electric eye valve (17) at both ends of the tee on the second transfer unit are both in the closed and clamped state. Step 2: When the blower (15) in the primary dust removal system of converter 1 or 2 malfunctions, the primary dust removal system of converter 1 or 2 will be interlocked with the furnace front gun, the smelting will be interrupted, and at the same time, it will be urgently switched to the venting state. The chimney will inject nitrogen to extract the primary flue gas from the pipeline and equipment of the dry dust removal system of converter flue gas with the backup blower switching mechanism. After the injection and replacement are completed, if the primary dust removal system of converter 1 malfunctions, proceed to step 3; if the primary dust removal system of converter 2 malfunctions, proceed to step 6. Step 3: Close and clamp the first horizontal sliding electric eye valve (5) at the inlet of the blower (15) and the second horizontal sliding electric eye valve (17) at the outlet of the silencer (16) in the primary dust removal system of the No. 1 converter flue gas. At this time, the primary dust removal system of the No. 1 converter flue gas is isolated. Then, open and clamp the first horizontal sliding electric eye valve (5) in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 1 converter flue gas and the tee, and open and clamp the second horizontal sliding electric eye valve (17) in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 1 converter flue gas and the tee. Other equipment remains in its original state. Step 4: After all the spectacle valves are in position and clamped, open the standby fan thin oil station circulating cooling water system (12), standby fan thin oil lubrication system (10) and standby fan bearing nitrogen sealing system (11) in the standby fan switching mechanism. Step 5: After the standby fan thin oil station circulating cooling water system (12), standby fan thin oil lubrication system (10) and standby fan bearing nitrogen sealing system (11) are running stably, start the standby fan frequency converter (9) in the standby fan switching mechanism, thereby starting the standby dust removal fan (2) and putting the standby dust removal fan (2) in a low-speed running state of 300 rpm, waiting for the furnace front smelting recovery signal. After the furnace front preparation is completed, production can be resumed. Step 6: Close and clamp the first horizontal sliding electric eye valve (5) at the inlet of the blower (15) and the second horizontal sliding electric eye valve (17) at the outlet of the silencer (16) in the primary dust removal system of the No. 2 converter flue gas. At this time, the primary dust removal system of the No. 2 converter flue gas is isolated. Then, open and clamp the first horizontal sliding electric eye valve (5) in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 2 converter flue gas and the tee, and open and clamp the second horizontal sliding electric eye valve (17) in the standby blower switching mechanism that is connected to the primary dust removal system of the No. 2 converter flue gas and the tee. Other equipment remains in its original state. Step 7: After all the spectacle valves are in position and clamped, open the standby fan thin oil station circulating cooling water system (12), standby fan thin oil lubrication system (10) and standby fan bearing nitrogen sealing system (11) in the standby fan switching mechanism. Step 8: After the standby fan thin oil station circulating cooling water system (12), standby fan thin oil lubrication system (10) and standby fan bearing nitrogen sealing system (11) are running stably, start the fan frequency converter (9) in the standby fan switching mechanism, thereby starting the standby dust removal fan (2) and putting the standby dust removal fan (2) in a low-speed running state of 300 rpm, waiting for the furnace front smelting recovery signal. Production can be resumed after the furnace front preparation is completed.

7. A method of operating a basic oxygen furnace flue gas dry cleaning system with a back-up fan switching mechanism as claimed in claim 6, characterised in that: In step two, the completion of ejection and replacement means that there is no smoke or dust in front of the furnace and the CO concentration is less than 24 ppm as detected.

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