Vacuum breaking flue gas treatment process for VD furnace

Abstract

The invention provides a VD furnace vacuum breaking flue gas treatment process, and relates to the technical field of VD furnace vacuum breaking flue gas treatment, and the VD furnace vacuum breaking flue gas treatment process comprises the following steps: S1, vacuum negative pressure establishment: starting a multi-stage vacuum pump through a control system, monitoring pressure sensor data between a bag-type dust collector and the vacuum pump in real time, and when the negative pressure of the system is stably reduced to be less than 500Pa, starting the vacuum pump; and starting the pulse dust cleaning system of the bag-type dust collector. According to the VD furnace vacuum breaking flue gas treatment process, a PLC automatic control system is utilized, full-process linkage of negative pressure monitoring, ash removal triggering, ash discharging operation and pump set starting and stopping is achieved, the resistance of a bag-type dust collector is accurately monitored in cooperation with a differential pressure measurement method, a graded ash removal strategy is triggered, high-resistance strong injection is achieved, and low-intensity ash removal is achieved during ash discharging; the dust extraction efficiency is prevented from being influenced by filter bag blockage, the service life of the filter bag is prolonged, the equipment fault occurrence rate can be reduced through the starting and stopping sequence of the multi-stage vacuum pump, and the manual intervention cost and spare part loss are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of VD furnace broken vacuum flue gas treatment, in particular to a VD furnace broken vacuum flue gas treatment process. BACKGROUND

[0002] In the field of steel smelting, VD furnace is the key equipment to realize deep denitrogenation and dehydrogenation of molten steel and improve the purity of steel. In the operation process, after vacuum refining, the "broken vacuum" operation needs to be performed, that is, atmospheric air is introduced into the closed furnace body to restore normal pressure. This process will be accompanied by a large amount of high-temperature dust-containing flue gas escaping instantaneously. The flue gas contains iron oxide dust, volatile organic compounds (VOCs) and trace toxic gases (such as NOx and SO2). If not properly treated, it will not only cause the dust concentration in the workshop to exceed the standard (usually 50-100 mg / m 3 , but also aggravate air pollution.

[0003] The existing treatment method mainly adopts rough exhaust and simple filtration, so there is low precision in negative pressure control. The molten steel splashes or dust escapes due to sudden pressure change, the filter bag is easily blocked and damaged due to high temperature and oil pollution, the filtration efficiency decays quickly, and there is a lack of intelligent monitoring and emergency protection, which easily causes secondary pollution when the equipment fails. At the same time, the traditional process does not develop a standardized maintenance scheme for key components such as fire-resistant filter and vacuum pump, which shortens the service life of the equipment and increases the operation and maintenance cost. Therefore, it is an urgent need for the steel industry to develop a VD furnace broken vacuum flue gas treatment process with high-precision negative pressure control, high-efficiency purification, intelligent protection and standardized operation and maintenance. SUMMARY

[0004] The present application is made in view of the above problems, and aims to provide a VD furnace broken vacuum flue gas treatment process to solve the problems raised in the background To achieve the above-mentioned purpose, the present application provides the following technical scheme: a VD furnace broken vacuum flue gas treatment process, comprising the following steps: S1, vacuum negative pressure establishment: Start the multi-stage vacuum pump through the control system, monitor the pressure sensor data between the bag filter and the vacuum pump in real time, start the pulse dust cleaning system of the bag filter, and confirm that the fire-resistant filter is normal and not blocked. At this time, a stable negative pressure field is formed in the flow path between the furnace body broken vacuum port, the fire-resistant filter, the bag filter and the vacuum pump; S2, broken vacuum dust capture: After the VD furnace completes the denitrogenation and dehydrogenation of molten steel and the vacuum ends, the water-cooled furnace cover is kept closed, and the multi-stage vacuum pump is not stopped. The broken vacuum program and the dust suppression system are linked through the control system, the broken vacuum time and the negative pressure maintenance range are set, and the broken vacuum process adopts staged pressure relief control to avoid the splashing of molten steel or the escape of dust due to sudden pressure change in the furnace. S3. Flue gas purification treatment: The dust-laden airflow, after being initially filtered by the flame arrestor filter, enters the bag filter. Under the continuous suction of the multi-stage vacuum pump, the airflow passes through the PPS / PTFE filter bag, and fine particles are adsorbed on the surface of the filter bag. The purified airflow then enters the multi-stage vacuum pump. S4. Flue gas purification and self-cleaning stage: The resistance of the bag filter is monitored in real time, and the pulse cleaning system is automatically started to avoid filter bag blockage affecting dust extraction efficiency. The bag filter hopper is equipped with a material level monitoring device and an automatic ash discharge valve. S5. Post-breakout processing: After 2-3 minutes of venting, monitor the pressure inside the furnace to rise to atmospheric pressure. Confirm that the negative pressure of the system is still stable and the smoke and dust are basically removed by the pressure sensor. Close the venting valve of the furnace body, maintain the operation of the multi-stage vacuum pump, and remove the remaining smoke and dust a second time. Then, turn off the multi-stage vacuum pump, and then turn off the pulse cleaning system of the bag filter. Finally, lift the water-cooled furnace cover to ensure that all the smoke and dust from venting is collected and to prevent the smoke and dust from overflowing when the cover is opened.

[0005] S6. Maintenance procedures: Disassemble the quick-release interface of the flame arrestor filter, check the dust accumulation on the surface of the metal filter screen, and clean it by backflushing with compressed air.

[0006] Furthermore, in step S1, the control system adopts a PLC control system and a bag filter pulse cleaning system, with an initial cleaning time of 10 seconds and an interval of 5 minutes.

[0007] Furthermore, in step S1, the multi-stage vacuum pump consists of a 3-4# stage pump and a secondary pump 1+2#. The multi-stage vacuum pump is activated in the following order: the 3-4# stage pump is activated first, followed by the secondary pump 1+2# after 10 seconds. The pulse cleaning system of the bag filter is activated when the negative pressure value drops to <500Pa.

[0008] Furthermore, in step S1, the flame arrestor filter is in a normal, unclogging state when the pressure difference before and after it is <3 kPa.

[0009] Furthermore, in step S2, the vacuum degree of the VD furnace during the denitrification and dehydrogenation of molten steel is ≤67Pa, the vacuum breaking time is 2-3 minutes, the negative pressure is maintained in the range of 100-300Pa, and the vacuum breaking process adopts staged pressure relief control. The negative pressure is maintained at 100-150Pa in the first minute, and then gradually adjusted to 200-300Pa in the subsequent 1-2 minutes.

[0010] Further, in the step S4, the bag dust collector resistance is monitored by using the differential pressure measurement method, the pressure difference between the inlet and outlet of the bag dust collector is measured, the overall resistance is directly reflected, the automatic ash removal instruction is triggered by the control system, the ash removal valve is opened for 30 seconds, the pulse cleaning system is maintained at low intensity during the ash removal process, the blowing pressure is 0.3 MPa, and the interval is 30 seconds, when the bag dust collector resistance is greater than 1200 Pa, the pulse cleaning system is automatically started.

[0011] Further, the formula of the differential pressure measurement method is: the total resistance of the bag dust collector ΔP = the outlet pressure P2 - the inlet pressure P1, and because the system is operated under negative pressure, P1 and P2 are negative values, and ΔP is a positive value, representing the pressure loss.

[0012] Further, in the step S4, the pulse cleaning system, when the resistance data received by the PLC control system is less than the preset threshold value, automatically sends an instruction to the pulse cleaning system of the bag dust collector, opens the compressed air blowing pressure 0.5 MPa, and the time is 15 seconds, and stops cleaning after the resistance is reduced to below 800 Pa.

[0013] Further, in the step S5, the multi-stage vacuum pump closing sequence is to stop the second stage pump 1+2# first, stop the 3-4# stage pump after 30 seconds, maintain the multi-stage vacuum pump running for 30 seconds, and secondly extract the residual smoke dust.

[0014] Further, the fire resistance filter adopts 316L stainless steel filter screen with a pore size of ≤0.5 mm, the number of filter screen layers is ≥3, and the surface of the filter screen is treated with anti-sticking coating, and the anti-sticking coating treatment adopts polytetrafluoroethylene.

[0015] Compared with the prior art, the present application has the following beneficial effects: by using the staged pressure relief control, the sudden change of the furnace pressure is avoided, the full-flow negative pressure dust collection under the closed state of the water-cooled furnace cover is matched, the staged pressure relief control effectively avoids the splashing of molten steel caused by the sudden change of the furnace pressure, ensures the safety of the operators and production equipment, and realizes the full collection of the VD furnace breaking smoke dust, completely eliminates the smoke overflow problem during the opening of the cover, through the double treatment of the preliminary filtration by the fire resistance filter and the high-efficiency purification by the PPS / PTFE filter bag, the fine particle dust adsorption rate is greatly improved, the dust emission concentration meets the environmental protection emission standard, and the atmospheric pollution is effectively reduced. By using the PLC automatic control system, the full-flow linkage of the negative pressure monitoring, the cleaning triggering, the ash removal operation, and the pump group starting and stopping is realized, the bag dust collector resistance is accurately monitored by using the differential pressure measurement method, the staged cleaning strategy is triggered, the high-resistance strong blowing and the low-intensity cleaning during the ash removal are realized, the filter bag service life is prolonged, the equipment failure rate is reduced by the multi-stage vacuum pump starting and stopping sequence, and the labor intervention cost and spare part loss are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments or the prior art, the drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the drawings, and other drawings can be obtained by those skilled in the art without creative effort.

[0017] Figure 1 It is a schematic diagram of the vacuum path system structure of the VD furnace broken space flue gas treatment process.

[0018] The purposes, functional features and advantages of the drawings will be further described with reference to the drawings. DETAILED DESCRIPTION

[0019] In order to make the purposes, technical solutions and advantages of the present application more clear, the present application will be described and explained in the following embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of the present application.

[0020] Obviously, the following description is only some examples or embodiments of the present application, and those skilled in the art can apply the present application to other similar situations without creative effort. In addition, it can be understood that although the efforts made in this development process may be complex and lengthy, some design, manufacture or production changes based on the technical content disclosed in the present application are only routine technical means for those skilled in the art related to the content disclosed in the present application, and should not be understood as insufficient disclosure of the content disclosed in the present application.

[0021] If not specifically stated, "including" and "containing" mentioned in the present application means open or closed. For example, "including" and "containing" can mean that other components not listed can also be included or contained, or only the listed components can be included or contained.

[0022] If not specifically stated, in the present application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or A and B are both true (or exist).

[0023] Term explanation: such as Figure 1As shown, a VD furnace broken empty flue gas treatment process comprises the following steps: S1, vacuum negative pressure establishment: Start the multi-stage vacuum pump through the control system, monitor the pressure sensor data between the bag filter and the vacuum pump in real time, open the pulse dust cleaning system of the bag filter when the system negative pressure is stable and drops to <500 Pa, the initial dust cleaning time is 10 seconds, the interval is 5 minutes, and the fire barrier filter is confirmed to be in a normal and non-clogging state. At this time, a stable negative pressure field is formed between the furnace body broken empty port, the fire barrier filter, the bag filter and the vacuum pump. In the step S1, the control system adopts a PLC control system. In the step S1, the multi-stage vacuum pump is a 3-4# stage pump and a two-stage pump 1+2#, and the multi-stage vacuum pump is started in the order of first starting the 3-4# stage pump and then starting the two-stage pump 1+2# after 10 seconds. In the step S1, the normal and non-clogging state of the fire barrier filter is that the pressure difference before and after is <3 kPa. The fire barrier filter adopts a 316L stainless steel filter screen with a pore size ≤0.5 mm and a filter screen layer number ≥3 layers. The surface of the filter screen is treated by an anti-sticking coating, and the anti-sticking coating treatment adopts polytetrafluoroethylene. The staged pressure relief control avoids sudden changes in the furnace pressure, and the full-process negative pressure dust collection under the closed state of the water-cooled furnace cover is matched. The staged pressure relief control effectively avoids the splashing of molten steel caused by sudden changes in the furnace pressure, ensures the safety of operators and production equipment, realizes the full collection of VD furnace broken empty dust through the design of secondary extraction of residual smoke dust 30 seconds after breaking empty, completely eliminates the problem of smoke overflow during opening, and greatly improves the fine particle dust adsorption rate through the double treatment of preliminary filtration by the fire barrier filter and high-efficiency purification by the PPS / PTFE filter bag. The dust emission concentration meets the environmental protection emission standard, effectively reduces air pollution, realizes the full-process linkage of negative pressure monitoring, dust cleaning triggering, dust removal operation and pump group starting and stopping through the PLC automatic control system, accurately monitors the resistance of the bag filter through the differential pressure measurement method, triggers the staged dust cleaning strategy, and cleans the dust at a high resistance and a low intensity during dust removal. This not only avoids the influence of filter bag clogging on dust extraction efficiency, but also prolongs the service life of the filter bag. The starting and stopping sequence of the multi-stage vacuum pump can reduce the equipment failure rate, reduce the cost of manual intervention and the loss of spare parts; S2, broken empty dust capture: After the VD furnace completes the denitrogenation and dehydrogenation of molten steel and the vacuum ends, the water-cooled furnace cover is kept closed, and the multi-stage vacuum pump is not stopped. The control system links the broken empty program with the smoke dust suppression system, sets the broken empty time and the negative pressure maintenance range, and adopts staged pressure relief control during the broken empty process. The negative pressure is maintained at 100-150 Pa within the first minute, and is gradually adjusted to 200-300 Pa in the subsequent 1-2 minutes to avoid the splashing of molten steel or the escape of smoke dust caused by sudden changes in the furnace pressure. In the step S2, the vacuum degree in the VD furnace during the denitrogenation and dehydrogenation of molten steel is ≤67 Pa, the broken empty time is 2-3 minutes, and the negative pressure maintenance range is 100-300 Pa. S3, smoke gas purification treatment: The dust-containing gas flow preliminarily filtered by the fire-resistant filter enters the bag-type dust collector, under the continuous suction of the multi-stage vacuum pump, the gas flow passes through the PPS / PTFE filter bag, fine particles are adsorbed on the surface of the filter bag, and the purified gas flow enters the multi-stage vacuum pump; S4, flue gas purification self-cleaning stage: Real-time monitoring of the bag-type dust collector resistance, when the resistance > 1200Pa, the pulse dust cleaning system is automatically started to avoid filter bag blockage affecting dust extraction efficiency, the bag-type dust collector ash bucket is provided with a material level monitoring device and an automatic ash unloading valve, when the material level reaches 60% of the ash bucket volume, the control system triggers an automatic ash unloading instruction, the ash unloading valve is opened for 30 seconds, and the pulse dust cleaning system is maintained at low intensity during the ash unloading process, with a blowing pressure of 0.3MPa, and an interval of 30 seconds, in the step S4, the bag-type dust collector resistance is monitored by using a differential pressure measurement method, by measuring the pressure difference between the inlet and outlet of the bag-type dust collector, the overall resistance is directly reflected, the formula of the differential pressure measurement method is: the total resistance of the bag-type dust collector ΔP = outlet pressure P2 - inlet pressure P1, and because the system is operated under negative pressure, P1 and P2 are negative values, and ΔP is a positive value, representing pressure loss, in the step S4, the pulse dust cleaning system, when the resistance data received by the PLC control system is less than the preset threshold value, automatically sends an instruction to the bag-type dust collector pulse dust cleaning system, opens the compressed air blowing pressure to 0.5MPa, and the time is 15 seconds, and the dust cleaning is automatically stopped after the resistance is reduced to below 800Pa; S5, post-breaking follow-up treatment: After breaking the vacuum for 2-3 minutes, the furnace pressure is monitored to rise to normal pressure, the system negative pressure is confirmed to be stable through the pressure sensor, the smoke dust is basically extracted, the furnace breaking vacuum valve is closed, the multi-stage vacuum pump is maintained to operate for 30 seconds, the residual smoke dust is extracted again, then the multi-stage vacuum pump is closed, the bag-type dust collector pulse dust cleaning system is closed, and finally the water-cooled furnace cover is lifted to ensure that the breaking smoke dust is fully collected, and to avoid smoke dust overflow when the cover is opened, in the step S5, the multi-stage vacuum pump is closed in the order of stopping the second pump 1+2# first, and then stopping the third and fourth pumps 3-4# after 30 seconds.

[0024] S6, maintenance treatment: The quick-release interface of the fire-resistant filter is disassembled, the dust accumulation on the surface of the metal filter screen is checked, if the blocked area > 30%, compressed air backwashing cleaning (pressure 0.4MPa, distance from the filter screen 20cm) is performed, the side door of the bag-type dust collector is opened, the dust adhesion on the surface of the filter bag is checked, if there is local damage, the filter bag is replaced, the dust collected in the ash bucket is emptied, the detachable filter screen at the inlet of the vacuum pump is disassembled, the possible residual trace dust is cleaned, and the turbidity of the oil in the vacuum pump is checked, and if it is turbid, it is replaced. Based on the above description, the VD furnace emptying flue gas treatment process realizes zero escape of emptying smoke dust through the closed loop design of staged pressure relief, negative pressure continuous maintenance and secondary residual suction. In the process, 100-300 Pa precise negative pressure regulation is adopted to avoid the splashing of molten steel and the overflow of smoke dust caused by sudden change of pressure in the furnace. In combination with the steps of secondary dust suction 30 seconds after emptying, negative pressure confirmation before uncovering and the like, the total amount of smoke dust is ensured to enter the treatment system. The three-layer 316L anti-sticking filter screen and the double filtration structure of PPS / PTFE filter bag of the fire barrier filter greatly improve the adsorption efficiency of fine particle smoke dust. At the same time, the pulse dust cleaning system is automatically stopped (800 Pa or below) according to the resistance, which avoids the blockage of the filter bag affecting the dust suction rate, meets the environmental protection emission requirements, and eliminates the production delay caused by the adhesion of smoke dust to the furnace body or equipment. The multi-stage vacuum pump is controlled in sequence of starting first and stopping later. The 3-4# stage pump is started first, and the 1+2# secondary pump is started later. The pump stopping sequence is reversed. In combination with the differential pressure real-time monitoring mechanism, the damage of equipment caused by system pressure impact is avoided. The fire barrier filter is designed for quick disassembly, the filter bag damage detection and the ash bucket automatic unloading function reduce the frequency of manual maintenance. The vacuum pump oil inspection and inlet filter screen cleaning maintenance process can avoid equipment failure in advance. In combination with the differential pressure regulation of the pulse dust cleaning system, the service life of the filter bag and the vacuum pump is guaranteed, and the comprehensive cost of material replacement and maintenance is reduced.

[0025] The following examples are implemented on the premise of the technical scheme of the present application, and detailed implementation modes and specific operation processes are given. However, the protection scope of the present application is not limited to the following examples.

[0026] Example Table 1 is a comparison between the existing VD furnace emptying flue gas treatment process and the VD furnace emptying flue gas treatment process of the present application.

[0027] Table 1 As can be seen, compared with the prior art, the VD furnace emptying flue gas treatment process of the present application avoids pressure mutation through staged pressure relief precise control, effectively eliminates molten steel splashing and smoke dust escape, the filter material is adapted to high-temperature dust conditions through targeted selection, is not easily affected by high temperature and oil stains, the blockage and damage rate is significantly reduced, the filtration efficiency is long-term stable, the intelligent monitoring and emergency protection system is equipped, the equipment operation abnormality can be quickly responded and treated, the secondary pollution is avoided from the root, at the same time, the standardized maintenance scheme is formulated for the key components such as the fire barrier filter and the vacuum pump, the maintenance threshold and the operation process are clear, and the service life of the equipment is effectively prolonged.

[0028] Note that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration, function, and effect as the technical idea of the present application are included in the technical scope of the present application. Furthermore, other modes constructed by applying various modifications to the embodiments, or by combining part of the configurations of the embodiments, which can be conceived by those skilled in the art, without departing from the spirit of the present application, are also included in the scope of the present application.

Claims

1. A process for treating flue gas from a VD furnace, characterized in that: Includes the following steps: S1. Vacuum negative pressure establishment: The control system starts the multi-stage vacuum pump, monitors the pressure sensor data between the bag filter and the vacuum pump in real time, starts the pulse cleaning system of the bag filter, and confirms that the flame arrestor filter is in normal and unblocked condition. At this time, a stable negative pressure field is formed in the flow path between the furnace body vent, the flame arrestor filter, the bag filter and the vacuum pump. S2, Smoke and Dust Capture: After the VD furnace completes the denitrification and dehydrogenation of the molten steel and the vacuum maintenance is completed, the water-cooled furnace cover is kept closed and the multi-stage vacuum pump is not stopped. The vacuum breaking program is linked with the dust suppression system through the control system. The vacuum breaking time and negative pressure maintenance range are set. The vacuum breaking process adopts graded pressure relief control to avoid sudden pressure changes in the furnace that could cause molten steel to splash or dust to escape. S3. Flue gas purification treatment: The dust-laden airflow, after being initially filtered by the flame arrestor filter, enters the bag filter. Under the continuous suction of the multi-stage vacuum pump, the airflow passes through the PPS / PTFE filter bag, and fine particles are adsorbed on the surface of the filter bag. The purified airflow then enters the multi-stage vacuum pump. S4. Flue gas purification and self-cleaning stage: The resistance of the bag filter is monitored in real time, and the pulse cleaning system is automatically started to avoid filter bag blockage affecting dust extraction efficiency. The bag filter hopper is equipped with a material level monitoring device and an automatic ash discharge valve. S5. Post-breakout processing: After 2-3 minutes of venting, monitor the pressure inside the furnace to rise to atmospheric pressure. Confirm that the negative pressure of the system is still stable and the smoke and dust are basically removed by the pressure sensor. Close the venting valve of the furnace body, maintain the operation of the multi-stage vacuum pump, and remove the remaining smoke and dust a second time. Then, turn off the multi-stage vacuum pump, and then turn off the pulse cleaning system of the bag filter. Finally, lift the water-cooled furnace cover to ensure that all the smoke and dust from venting is collected and to prevent the smoke and dust from overflowing when the cover is opened. S6. Maintenance procedures: Disassemble the quick-release interface of the flame arrestor filter, check the dust accumulation on the surface of the metal filter screen, and clean it by backflushing with compressed air.

2. The VD furnace flue gas treatment process according to claim 1, characterized in that: In step S1, the control system adopts a PLC control system and a bag filter pulse cleaning system, with an initial cleaning time of 10 seconds and an interval of 5 minutes.

3. The process for treating vented flue gas from a VD furnace according to claim 1, characterized in that: In step S1, the multi-stage vacuum pump consists of stage 3-4 and stage 1+2. The activation sequence of the multi-stage vacuum pump is to start stage 3-4 first, and then stage 1+2 after 10 seconds. The pulse cleaning system of the bag filter is activated when the negative pressure value drops to <500Pa.

4. The process for treating vented flue gas from a VD furnace according to claim 1, characterized in that: In step S1, the flame arrestor filter is in a normal, unclogging state when the pressure difference before and after it is <3 kPa.

5. The process for treating vented flue gas from a VD furnace according to claim 1, characterized in that: In step S2, the vacuum degree of the VD furnace is ≤67Pa during the denitrification and dehydrogenation of molten steel. The vacuum breaking time is 2-3 minutes, and the negative pressure is maintained in the range of 100-300Pa. The vacuum breaking process adopts staged pressure relief control. The negative pressure is maintained at 100-150Pa in the first minute, and then gradually adjusted to 200-300Pa in the following 1-2 minutes.

6. The VD furnace flue gas treatment process according to claim 1, characterized in that: In step S4, the resistance of the bag filter is monitored using differential pressure measurement. By measuring the pressure difference between the inlet and outlet of the bag filter, the overall resistance is directly reflected. The control system triggers an automatic ash discharge command, and the ash discharge valve is open for 30 seconds. During the ash discharge process, the pulse cleaning system is maintained at a low intensity with a blowing pressure of 0.3 MPa and an interval of 30 seconds. When the resistance of the bag filter is >1200 Pa, the pulse cleaning system is automatically started.

7. The VD furnace flue gas treatment process according to claim 6, characterized in that: The differential pressure measurement formula is: Total resistance of bag filter ΔP = outlet pressure P2 - inlet pressure P1. Since the system operates under negative pressure, P1 and P2 are both negative values, and ΔP is a positive value, representing pressure loss.

8. The process for treating vented flue gas from a VD furnace according to claim 1, characterized in that: In step S4, when the resistance data received by the PLC control system is less than the preset threshold, the pulse cleaning system automatically sends a command to the bag filter pulse cleaning system to start the compressed air jetting pressure of 0.5MPa for 15 seconds, and automatically stops cleaning after the resistance drops below 800Pa.

9. The VD furnace flue gas treatment process according to claim 1, characterized in that: In step S5, the multi-stage vacuum pump is shut down in the following order: first, stop the second-stage pump 1+2#, then stop the third-stage pump 3-4# after 30 seconds, and maintain the multi-stage vacuum pump running for 30 seconds to remove residual smoke and dust a second time.

10. The process for treating vented flue gas from a VD furnace according to claim 1, characterized in that, The flame arrestor filter uses 316L stainless steel filter screen with a pore size ≤0.5mm, ≥3 filter screen layers, and the filter screen surface is treated with an anti-stick coating made of polytetrafluoroethylene.

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