A continuous and safe system and method for treating converter flue gas

Abstract

This invention provides a continuous and safe system and method for treating converter flue gas. The system includes a converter body, a vaporization cooling flue, a flue gas pretreatment device, and a waste heat recovery device. The flue gas pretreatment device includes a closed cavity with a flue gas inlet, a flue gas outlet, a dust discharge port, and an air inlet. A movable partition is installed inside the cavity. The converter body outlet is connected to the flue gas inlet via the vaporization cooling flue, and the flue gas outlet is connected to the waste heat recovery device. This invention uses a flue gas pretreatment device to ensure a stable and continuous output of intermittently generated flue gas, avoiding the impact of flue gas fluctuations on the operational stability of the waste heat recovery device. This results in higher quality steam, effectively extends the service life of the waste heat recovery device, and reduces maintenance costs. Simultaneously, it allows high-temperature combustible flue gas to mix and react with air above its auto-ignition point, avoiding the temperature conditions for combustible gas explosions and preventing safety issues during gas recovery.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking technology, specifically relating to a continuous and safe treatment system and method for converter flue gas. Background Technology

[0002] Converter steelmaking is currently the most important steelmaking method, accounting for more than 85% in China. Its process is a complex high-temperature oxidation reaction mainly involving carbon and oxygen, which produces a large amount of high-temperature dusty flue gas.

[0003] The converter produces a large amount of flue gas, the main components of which are CO (approximately 66%), CO2 (approximately 16%), and N2 (approximately 17%), with small amounts of O2 and Ar. Because of the high CO content, converter flue gas is also called converter gas. The initial temperature of converter gas is around 1600℃, and it contains a large amount of dust generated during steelmaking, with a dust content of approximately 80–150 g / m³. 3 The main components of the dust are FeO, Fe, CaO, MnO, SiO2 and C, etc. Converter gas has flammable and explosive characteristics. The conditions for its explosion are: 1) CO content is within the explosion limit range; 2) CO is mixed with O2 below the auto-ignition point (650℃); 3) it comes into contact with an open flame (reaching the minimum ignition energy).

[0004] Currently, there are two common methods for treating converter flue gas: The first is the OG method, also known as wet dust removal. Its main process involves passing converter flue gas at around 1600°C through a vaporization flue for waste heat recovery. When the flue gas temperature drops to around 900°C, a large amount of water is sprayed for cooling, which also serves as coarse dust removal and explosion prevention. After further fine dust removal using venturi tube water spraying, high-calorific-value, low-oxygen-content gas is recovered, while low-calorific-value or high-oxygen-content gas is ignited and discharged into the atmosphere. The second is dry dust removal, mainly the LT method and the DDS method. Its main process involves passing converter flue gas at around 1600°C through a vaporization flue for waste heat recovery. When the flue gas temperature drops to around 900°C, water mist is sprayed for cooling, followed by fine dust removal using an electrostatic precipitator. High-quality gas is then recovered, while low-quality gas is ignited and discharged into the atmosphere.

[0005] The aforementioned converter flue gas dust removal methods are not truly dry dust removal systems. To prevent explosions of converter gas below its auto-ignition point, water spraying is used after recovering the waste heat from the high-temperature section (1600℃~900℃) of the converter flue gas. This results in the complete waste of the waste heat (900℃~200℃) in the converter flue gas, along with a large amount of water. Furthermore, since converter smelting is an intermittent operation, the generation and treatment of converter flue gas are also intermittent. The alternating presence of high-temperature combustible flue gas and air in the flue gas treatment system introduces two drawbacks: first, the intermittent flue gas heat causes the steam generated in the vaporization cooling flue to flue, making it impossible to produce high-quality superheated steam; second, the alternating flow of high-temperature combustible flue gas and air into the flue gas treatment system creates more safety hazards, especially the risk of explosion. Existing patent literature discloses many methods for recovering low-temperature waste heat from converter flue gas, but none solves the problem of the intermittent transmission of high-temperature combustible flue gas. Summary of the Invention

[0006] The purpose of this invention is to provide a continuous and safe treatment system and method for converter flue gas, which can at least solve some of the defects existing in the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A continuous and safe converter flue gas treatment system includes a converter body, a vaporization cooling flue, a flue gas pretreatment device, and a waste heat recovery device. The flue gas pretreatment device includes a closed cavity with a flue gas inlet and a flue gas outlet at the top. A movable partition is provided inside the cavity, and a dust discharge port is provided at the bottom. An air inlet is provided on the cavity near the flue gas outlet. The outlet of the converter body is connected to the flue gas inlet of the cavity through the vaporization cooling flue, and the flue gas outlet of the cavity is connected to the waste heat recovery device.

[0009] Furthermore, the flue gas inlet and the flue gas outlet are located on the same side of the movable partition, and the distance between the flue gas inlet and the movable partition is less than the distance between the flue gas outlet and the movable partition.

[0010] Furthermore, at least one dust removal baffle is provided between the flue gas inlet and the flue gas outlet.

[0011] Furthermore, the flue gas outlet of the cavity is connected to the waste heat recovery device via an insulated flue.

[0012] Furthermore, a coarse ash bin is provided at the bottom of the insulated flue.

[0013] Furthermore, the waste heat recovery device includes a split-type waste heat boiler and a fine dust removal mechanism. The split-type waste heat boiler has a medium-high temperature section and a low temperature section. The fine dust removal mechanism is connected between the medium-high temperature section and the low temperature section of the split-type waste heat boiler. The flue gas outlet is connected to the inlet of the medium-high temperature section of the split-type waste heat boiler.

[0014] Furthermore, the medium- and high-temperature section of the split-type waste heat boiler is arranged vertically, with an air inlet at the bottom and an air outlet at the top, and multiple horizontally spaced smooth heat exchange tube bundles inside; the low-temperature section of the split-type waste heat boiler has multiple finned serpentine water-cooled tubes inside; the medium- and high-temperature section and the low-temperature section of the split-type waste heat boiler share a steam drum.

[0015] Furthermore, the fine dust removal mechanism includes a dust collection box and a ceramic fiber filter cartridge disposed inside the dust collection box.

[0016] Furthermore, the aforementioned continuous and safe converter flue gas treatment system also includes a blower, which is connected to the outlet of the waste heat recovery device, and the outlet of the blower is connected to a venting chimney.

[0017] In addition, the present invention also provides a method for continuous and safe treatment of converter flue gas, which uses the above-mentioned treatment system and includes the following steps:

[0018] S1. The flue gas generated by the converter body undergoes radiative heat exchange through the vaporization cooling flue, reducing the flue gas temperature from 1450-1650℃ to 900℃.

[0019] S2. The flue gas from the outlet of the vaporization cooling flue enters the flue gas pretreatment device. When the flue gas flow rate is large, the movable baffle inside the flue gas pretreatment device moves away from the flue gas inlet to store and transport the excess high-temperature flue gas. When the flue gas flow rate is small or during the smelting interval, the movable baffle inside the flue gas pretreatment device moves towards the flue gas inlet to slowly release the stored high-temperature flue gas, so that the flue gas at the outlet always flows out with a stable flow rate and velocity.

[0020] S3. The high-temperature flue gas in the flue gas pretreatment device mixes with the air flowing in from the air inlet at the flue gas outlet and combusts.

[0021] S4. The flue gas processed in step S3 enters the waste heat recovery device for convective heat exchange.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) The converter flue gas continuous and safe treatment system provided by the present invention adopts a flue gas pretreatment device, which can make the intermittently generated flue gas output stably and continuously, avoiding the impact of flue gas fluctuations on the operational stability of the waste heat recovery device. It can generate higher quality steam and effectively extend the service life of the waste heat recovery device and reduce maintenance costs. At the same time, the flue gas pretreatment device mixes the high-temperature combustible flue gas with air above the auto-ignition point and produces a reaction, which not only effectively avoids the temperature conditions for combustible gas explosion, but also avoids various safety problems in the conventional coal gas recovery process.

[0024] (2) The converter flue gas continuous and safe treatment system provided by the present invention adopts the structure of a split waste heat boiler for waste heat recovery. At the same time, the fine dust removal mechanism is arranged between the medium and high temperature section and the low temperature section of the split waste heat boiler, so that the low temperature section is used for heat exchange with clean flue gas. This can avoid the problems of ash accumulation, bridging, blockage or severe wear and leakage that exist when existing waste heat boilers recover dusty waste gas.

[0025] (3) The continuous and safe treatment system for converter flue gas provided by the present invention can effectively recover most of the chemical heat and sensible heat in the converter flue gas, which is conducive to improving the energy efficiency of converter production; by adopting the filtration dust removal method, the dust content in the emitted flue gas can be less than 10mg / m³, which meets the requirements of ultra-low emission.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the converter flue gas continuous and safe treatment system of the present invention;

[0028] Figure 2 This is a schematic diagram of the flue gas pretreatment device in the continuous and safe treatment system for converter flue gas of the present invention.

[0029] Explanation of reference numerals in the attached drawings: 1. Converter body; 2. Fume hood; 3. Vaporization cooling flue; 4. Flue gas pretreatment device; 5. Insulated flue; 6. Coarse ash bin; 7. Medium and high temperature section; 8. Fine dust removal mechanism; 9. Fine ash bin; 10. Low temperature section; 11. Steam drum; 12. Fan; 13. Venting chimney; 41. Cavity; 42. Movable partition; 43. Flue gas inlet; 44. Dust removal baffle; 45. Flue gas outlet; 46. Air inlet; 47. Dust discharge port. Detailed Implementation

[0030] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an abutting connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0033] like Figure 1 and Figure 2As shown, this embodiment provides a continuous and safe treatment system for converter flue gas, including a converter body 1, a vaporization cooling flue 3, a flue gas pretreatment device 4, and a waste heat recovery device. The flue gas pretreatment device 4 includes a closed cavity 41. The top of the cavity 41 is provided with a flue gas inlet 43 and a flue gas outlet 45. The cavity 41 is provided with a movable partition 42 inside. The bottom of the cavity 41 is provided with a dust discharge port 47. An air inlet 46 is provided on the cavity 41 near the flue gas outlet 45. The outlet of the converter body 1 is connected to the flue gas inlet 43 of the cavity 41 through the vaporization cooling flue 3. The flue gas outlet 45 of the cavity 41 is connected to the waste heat recovery device. During operation, the flue gas generated by the converter body 1 is cooled by the vaporization cooling flue 3 and then enters the flue gas pretreatment device 4. In the flue gas pretreatment device 4, the movable baffle 42 inside moves accordingly according to the flue gas flow rate to adjust the volume of flue gas contained in the cavity 41, thereby ensuring that the flue gas flow rate and velocity at the flue gas outlet 45 remain constant. At the same time, at the flue gas outlet 45, combustible gases (such as CO) in the high-temperature flue gas mix and burn with the air flowing in from the air inlet 46. The flue gas treated by the flue gas pretreatment device 4 enters the waste heat recovery device to recover the sensible heat in the flue gas. The converter flue gas continuous and safe treatment system provided in this embodiment adopts a flue gas pretreatment device 4, which can ensure a stable and continuous output of intermittently generated flue gas, avoiding the impact of flue gas fluctuations on the operational stability of the waste heat recovery device. This not only produces higher quality steam but also effectively extends the service life of the waste heat recovery device and reduces maintenance costs. At the same time, the flue gas pretreatment device 4 mixes and reacts the high-temperature combustible flue gas with air above its auto-ignition point, effectively avoiding the temperature conditions for combustible gas explosions and various safety issues in conventional coal gas recovery processes.

[0034] A fume hood 2 is installed between the converter body 1 and the vaporization cooling flue 3. One end of the fume hood 2 covers the converter body 1 to capture the flue gas generated in the converter body 1, and the other end is connected to the inlet of the vaporization cooling flue 3 so that the captured flue gas can enter the vaporization cooling flue 3. The vaporization cooling flue 3 can reduce the flue gas temperature from 1450-1650℃ to about 900℃ through radiative heat exchange.

[0035] As a specific implementation method, such as Figure 2As shown, the cavity 41 of the flue gas pretreatment device 4 is usually designed as a cuboid, but it can also be designed as a cylinder or other shapes. The side walls of the cavity 41 can be made of refractory bricks, or they can be set as water-cooled walls or vaporization cooling walls, which can withstand high-temperature flue gas. The movable baffle 42 inside the cavity 41 is constructed of refractory material, has the same cross-section as the cavity 41, and is in close contact with the surrounding walls. It can move horizontally along the interior of the flue gas pretreatment device 4 to adjust the flue gas storage and transportation space. The movement of the movable baffle 42 is adjusted by the control system according to the flue gas flow rate, pressure, or velocity. It can store a large amount of flue gas generated during the peak smelting period and release the flue gas during the smelting trough or smelting interval, so that the flue gas flow rate or velocity in the flue gas outlet 45 remains basically constant. The movable baffle 42 is positioned such that the flue gas inlet 43 and the flue gas outlet 45 are located on the same side of the movable baffle 42, and the distance between the flue gas inlet 43 and the movable baffle 42 is less than the distance between the flue gas outlet 45 and the movable baffle 42. The air inlet 46 is located near the flue gas outlet 45. The amount of air flowing in can be controlled by a valve to ensure that all CO in the flue gas is burned and that there is no excess air. The dust outlet 47 is mainly used to discharge the dust deposited in the flue gas pretreatment device 4. To ensure that the bottom of the flue gas pretreatment device 4 does not accumulate too much dust, the dust is cleaned from the dust outlet 47 every once in a while to reduce the accumulation of dust in subsequent pipes and devices.

[0036] Preferably, a dust removal baffle 44 is provided between the flue gas inlet 43 and the flue gas outlet 45. The dust removal baffle 44 is fixed on the inner wall surface of the top of the cavity 41 and is mainly used to change the flow direction of the flue gas so that the particulate matter in the flue gas can settle better. The dust removal baffle 44 can be provided as one piece or multiple pieces arranged side by side at intervals.

[0037] In some embodiments, the flue gas outlet 45 of the cavity 41 is connected to the waste heat recovery device through an insulated flue 5. The outside of the insulated flue 5 is a metal pipe, and the inside is a sprayed refractory material, which can withstand the high temperature of the flue gas.

[0038] As an optimized technical solution, the waste heat recovery device includes a split-type waste heat boiler and a fine dust removal mechanism 8. The split-type waste heat boiler has a medium-high temperature section 7 and a low temperature section 10. The fine dust removal mechanism 8 is connected between the medium-high temperature section 7 and the low temperature section 10 of the split-type waste heat boiler. The flue gas outlet 45 is connected to the inlet of the medium-high temperature section 7 of the split-type waste heat boiler. The flue gas treated by the flue gas pretreatment device 4 enters the medium-high temperature section 7 of the split-type waste heat boiler for heat exchange, recovering the sensible heat of the medium-high temperature section in the flue gas. After cooling, the flue gas enters the fine dust removal mechanism 8 for purification, and then enters the low temperature section 10 of the split-type waste heat boiler for heat exchange, recovering the sensible heat of the low temperature section in the flue gas. In this embodiment, a split-type waste heat boiler is used for waste heat recovery. At the same time, the fine dust removal mechanism 8 is arranged between the medium-high temperature section 7 and the low temperature section 10 of the split-type waste heat boiler, so that the low temperature section 10 is used for heat exchange with clean flue gas. This can avoid the problems of ash accumulation, bridging, blockage or severe wear and leakage that exist when existing waste heat boilers recover dusty waste gas.

[0039] Specifically, the medium-high temperature section 7 of the split-type waste heat boiler is vertically arranged, with the air inlet at the bottom and the air outlet at the top. It contains multiple horizontally spaced smooth heat exchange tube bundles. The flow direction of the flue gas within the medium-high temperature section 7 is perpendicular to the arrangement direction of the heat exchange tube bundles, which is more conducive to the absorption of waste heat and the deposition of dust. Specifically, the medium-high temperature section 7 of the split-type waste heat boiler has a metal pressure vessel shell on the outside and 2 to 5 evaporation cooling sections inside. These evaporation cooling sections consist of horizontally arranged heat exchange tube bundles. The heat exchange area and the number of heat exchange tube bundles in the evaporation section can usually be calculated based on the flue gas volume and temperature. Since the medium-high temperature section 7 of the split-type waste heat boiler is mainly used to recover the sensible heat of the flue gas at approximately 350°C or higher, horizontally arranged smooth heat exchange tube bundles can be used, and a certain spacing can be maintained between the heat exchange tube bundles. This avoids the dust bridging and blockage problems in the economizer section that occur in conventional integrated waste heat boilers.

[0040] The optimized design includes a dust removal device inside the medium-high temperature section 7 of the split-type waste heat boiler, which can periodically clean the dust adhering to the heat exchange wall surface; the medium-high temperature section 7 of the split-type waste heat boiler is also equipped with 4 to 8 explosion-proof valves, which can play an emergency explosion relief role when the pressure is too high.

[0041] Furthermore, a coarse ash bin 6 is installed on the insulated flue 5 at the bottom of the medium-high temperature section 7 of the split-type waste heat boiler for dust collection and discharge. To prevent air from entering the system during ash discharge, a safety valve and an airlock device are installed on the coarse ash bin 6. To ensure that the medium-high temperature section 7 of the split-type waste heat boiler maintains a high heat exchange efficiency, the ash cleaning device installed inside it cleans the dust every 2 to 20 hours, causing the dust adhering to the heat exchange wall surface to fall into the lower pipes and coarse ash bin 6.

[0042] Specifically, the fine dust removal mechanism 8 is arranged after the medium-high temperature section 7 of the split-type waste heat boiler. It includes a dust collection box and a ceramic fiber filter cartridge installed inside the dust collection box. The ceramic fiber filter cartridge uses a filter material made of aluminum silicate fiber, which has the characteristics of high porosity, high filtration accuracy, and resistance to acid and alkali corrosion. This fine dust removal mechanism 8 can typically withstand temperatures above 400℃ and is suitable for flue gas temperatures discharged from the medium-high temperature section 7 of the split-type waste heat boiler. Its filtration effect can be controlled according to the filtration area and flue gas velocity. The dust content in the flue gas after filtration can be stably lower than 10mg / m³, or even lower than 5mg / m³, fully meeting the requirements of ultra-low emissions. Preferably, a fine ash bin 9 is provided at the bottom of the dust collection box to collect the dust filtered by the fine dust removal mechanism 8. To prevent air from entering the system pipeline during ash discharge, the fine ash bin 9 is equipped with a valve and an airlock device. To ensure the filtration effect of the ceramic fiber filter cartridge and avoid excessive filtration resistance, the ceramic fiber filter cartridge is backflushed at regular intervals based on the filtration pressure test results. This allows the dust adhering to the filter surface to fall into the pipe or the fine ash bin 9 at the bottom, thus ensuring that the system maintains high dust removal efficiency and low resistance.

[0043] Specifically, the low-temperature section 10 of the split-type waste heat boiler is arranged after the fine dust removal mechanism 8. The exterior of the low-temperature section 10 is a metal pressure vessel shell, and the interior consists of multiple finned serpentine water-cooled tubes. Since the flue gas temperature entering the low-temperature section 10 of the split-type waste heat boiler is relatively low, typically around 350°C, finned serpentine tubes can be used in the low-temperature section 10 to improve heat exchange efficiency. Because the flue gas at this point is clean flue gas after being finely filtered by the fine dust removal mechanism 8, the serpentine tubes can be arranged more densely, and problems such as dust adhesion, bridging, and blockage will not occur. The temperature of the flue gas at the outlet of the low-temperature section 10 of the split-type waste heat boiler can typically be cooled to below 150°C.

[0044] In this embodiment, the medium-high temperature section 7 and the low temperature section 10 of the split waste heat boiler are different parts of a boiler and can be connected by a set of water and steam systems, sharing a steam drum 11.

[0045] Furthermore, the converter flue gas continuous and safe treatment system of this embodiment also includes a blower 12, which is connected to the outlet of the low temperature section 10 of the waste heat recovery device. As an optimized option, the blower 12 is usually a variable frequency speed-controlled induced draft fan used to draw flue gas from the pipeline. The flue gas drawn by the blower 12 enters the venting chimney 13 through the pipeline.

[0046] This embodiment also provides a method for the continuous and safe treatment of converter flue gas, which specifically includes the following process:

[0047] First, based on the tonnage and production scale of converter body 1, a continuous and safe converter flue gas treatment system as described in the above embodiment is constructed.

[0048] Then, when molten iron is added to the converter body 1 and oxygen blowing begins, the blower 12 is kept on. The suction force of the blower 12 draws the flue gas in the converter body 1 into the fume hood 2. The flue gas enters the vaporization cooling flue 3 through the fume hood 2 and undergoes radiative heat exchange. The flue gas temperature drops from 1450-1650℃ to about 900℃. During the initial blowing period of about 30-120 seconds, the fume hood 2 is raised appropriately to allow more air to enter the upper part of the converter body 1 and undergo a combustion reaction to generate carbon dioxide. The flue gas containing a large amount of carbon dioxide enters the pipe and can purge the air in the pipe.

[0049] Subsequently, flue gas at approximately 900°C from the outlet of the vaporization cooling flue 3 flows into the flue gas inlet of the flue gas pretreatment device 4. When the smelting intensity is high and the flue gas flow rate is large, the movable baffle 42 inside the flue gas pretreatment device 4 moves away from the flue gas inlet 43 to store the excess high-temperature flue gas, while ensuring that the flue gas at the flue gas outlet 45 flows out at a stable flow rate and velocity. When the smelting intensity is low or during the smelting interval, the movable baffle 42 inside the flue gas pretreatment device 4 moves towards the flue gas inlet 43 to slowly release the stored high-temperature flue gas, while ensuring that the flue gas at the flue gas outlet 45 flows out at a stable flow rate and velocity.

[0050] Meanwhile, the high-temperature combustible flue gas in the flue gas pretreatment device 4 mixes with the air flowing in from the air inlet 46 at the flue gas outlet 45 and combusts. The air inflow is controlled by a valve to ensure that all combustible gases in the high-temperature flue gas react. At the same time, particulate matter in the flue gas settles to the bottom of the flue gas pretreatment device 4 during the flow process.

[0051] Then, the high-temperature flue gas after passing through the flue gas pretreatment device 4 enters the medium-high temperature section 7 of the split waste heat boiler. At this time, the high-temperature flue gas enters from the lower part of the medium-high temperature section 7 of the split waste heat boiler and conducts convective heat exchange with the horizontal smooth heat exchange tube bundle inside the boiler. The flue gas temperature can be reduced to about 350℃. At the same time, some of the dust in the flue gas settles into the coarse ash bin 6 set at the bottom.

[0052] The flue gas, at approximately 350°C, discharged from the medium-high temperature section 7 of the split-type waste heat boiler enters the fine dust removal mechanism 8 for fine dust removal. By controlling the filtration area of ​​the ceramic fiber filter cartridge and the residence time of the flue gas, the dust content in the outlet flue gas can be reduced to below 10mg / m³, meeting ultra-low emission requirements. The clean flue gas after filtration by the ceramic fiber filter cartridge enters the low temperature section 10 of the split-type waste heat boiler, where it undergoes sufficient heat exchange with the finned serpentine water-cooled tubes installed inside the low temperature section 10, thereby reducing the flue gas temperature to below 150°C.

[0053] Finally, the low-temperature flue gas, after sufficient heat exchange in each section of the waste heat recovery device, enters the venting chimney 13 through the fan 12 and is then discharged into the atmosphere.

[0054] In summary, the continuous and safe converter flue gas treatment system provided by this invention can effectively recover most of the chemical heat and sensible heat in the converter flue gas, which is beneficial to improving the energy efficiency of converter production; by adopting a filtration-type dust removal method, the dust content in the emitted flue gas can be less than 10mg / m³, meeting the requirements of ultra-low emissions.

[0055] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A continuous and safe treatment system for converter flue gas, characterized in that: The system includes a converter body, a vaporization cooling flue, a flue gas pretreatment device, and a waste heat recovery device. The flue gas pretreatment device includes a closed cavity with a flue gas inlet and outlet at the top. A movable partition is provided inside the cavity, with the flue gas inlet and outlet located on the same side of the partition, and the distance between the flue gas inlet and the partition being less than the distance between the flue gas outlet and the partition. A dust discharge port is provided at the bottom of the cavity, and an air inlet is provided on the cavity near the flue gas outlet. The outlet of the converter body is connected to the flue gas inlet of the cavity through the vaporization cooling flue, and the flue gas outlet of the cavity is connected to the waste heat recovery device.

2. The continuous and safe converter flue gas treatment system as described in claim 1, characterized in that: At least one dust removal baffle is provided between the flue gas inlet and the flue gas outlet.

3. The continuous and safe converter flue gas treatment system as described in claim 1, characterized in that: The flue gas outlet of the cavity is connected to the waste heat recovery device via an insulated flue.

4. The continuous and safe converter flue gas treatment system as described in claim 3, characterized in that: The bottom of the insulated flue is equipped with a coarse ash bin.

5. The continuous and safe converter flue gas treatment system as described in claim 1, characterized in that: The waste heat recovery device includes a split-type waste heat boiler and a fine dust removal mechanism. The split-type waste heat boiler has a medium-high temperature section and a low temperature section. The fine dust removal mechanism is connected between the medium-high temperature section and the low temperature section of the split-type waste heat boiler. The flue gas outlet is connected to the inlet of the medium-high temperature section of the split-type waste heat boiler.

6. The continuous and safe converter flue gas treatment system as described in claim 5, characterized in that: The medium- and high-temperature section of the split-type waste heat boiler is arranged vertically, with an air inlet at the bottom and an air outlet at the top, and multiple horizontally spaced smooth heat exchange tube bundles inside; the low-temperature section of the split-type waste heat boiler has multiple finned serpentine water-cooled tubes inside; the medium- and high-temperature section and the low-temperature section of the split-type waste heat boiler share a steam drum.

7. The continuous and safe converter flue gas treatment system as described in claim 5, characterized in that: The fine dust removal mechanism includes a dust collection box and a ceramic fiber filter cartridge disposed inside the dust collection box.

8. The continuous and safe converter flue gas treatment system as described in claim 1, characterized in that: It also includes a fan, which is connected to the outlet of the waste heat recovery device, and the air outlet of the fan is connected to a venting chimney.

9. A method for continuous and safe treatment of converter flue gas, characterized in that: The processing system according to any one of claims 1 to 8 includes the following steps: S1. The flue gas generated by the converter body undergoes radiative heat exchange through the vaporization cooling flue, reducing the flue gas temperature from 1450-1650℃ to 900℃. S2. The flue gas from the outlet of the vaporization cooling flue enters the flue gas pretreatment device. When the flue gas flow rate is large, the movable baffle inside the flue gas pretreatment device moves away from the flue gas inlet to store and transport the excess high-temperature flue gas. When the flue gas flow rate is small or during the smelting interval, the movable baffle inside the flue gas pretreatment device moves towards the flue gas inlet to slowly release the stored high-temperature flue gas, so that the flue gas at the outlet always flows out with a stable flow rate and velocity. S3. The high-temperature flue gas in the flue gas pretreatment device mixes with the air flowing in from the air inlet at the flue gas outlet and combusts. S4. The flue gas processed in step S3 enters the waste heat recovery device for convective heat exchange.

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