Primary dry dust removal system for third-generation converter

Abstract

Disclosed in the present invention is a primary dry dust removal system for a third-generation converter. The primary dry dust removal system comprises a high-efficiency heat exchanger, a banana bend dust collector, a swirl heat recovery device, and high-temperature-resistant explosion-proof ultra-clean dust collectors. Raw coke oven gas from a converter enters the high-efficiency heat exchanger for heat exchange recovery. The banana bend dust collector is arranged between the high-efficiency heat exchanger and the swirl heat recovery device. The swirl heat recovery device is connected to at least one high-temperature-resistant explosion-proof ultra-clean dust collector. A clean coal gas is formed at a gas outlet of the high-temperature-resistant explosion-proof ultra-clean dust collector. The clean coal gas passes through a coal gas axial flow fan and a coal gas scrubber dehydrator and is then delivered to a coal gas switching station. Coal gas passed inspection is delivered to a coal gas holder. In the present invention, a traditional evaporative cold water spraying and electrostatic dust collector process is eliminated, and a high-efficiency heat exchanger and explosion-proof ultra-clean dust collector process is used, thereby achieving a high converter coal gas waste heat recovery efficiency and a safe and environmentally friendly dust removal system.

Description

Third generation converter primary dry dedusting system TECHNICAL FIELD

[0001] The application discloses a third generation converter primary dry dedusting system and belongs to the technical field of environmental protection dedusting equipment. BACKGROUND

[0002] Most of the converters in the Chinese steel industry adopt dry dedusting systems. At present, common dry dedusting systems mainly include the first generation converter primary dry dedusting system (LT method and DDS method) and the improved second generation converter primary dry dedusting system (an electrostatic precipitator is provided behind the coal cooling preposition, double coal cooling, coal cooling + metal filter cartridge, wet electrostatic precipitator and the like).

[0003] The existing converter coal gas dry dedusting system mainly has the following problems: 1. Water mist cooling is performed through an evaporative cooler, and the temperature is directly reduced from 900 DEG C to about 250 DEG C, and the high-quality heat is wasted without being recycled; 2. An electrostatic precipitator is adopted, and since a high-voltage power supply continuously discharges, once the mixed gas components in the electrostatic precipitator reach the explosion limit, explosion is easily generated, the equipment in the system is damaged, and the dedusting effect is affected; in addition, the discharge degree of the high-voltage power supply is different, and the voltage and current between the polar line and the polar plate greatly fluctuate, so that the dedusting efficiency of the electrostatic precipitator is affected, and the dust emission concentration at the outlet of the diffusion chimney greatly fluctuates.

[0004] The Chinese document CN111575435A discloses a third generation converter primary dry dedusting system for super-clean coal gas recovery, which comprises a converter, an evaporative cooler and a dust collector; the dust removal system further comprises a high-temperature phase change heat accumulator for smoke gas temperature stabilization; a gas outlet of the converter is connected to a gas inlet of the high-temperature phase change heat accumulator through a vaporization cooling flue; a gas outlet of the high-temperature phase change heat accumulator is connected to a gas inlet of the evaporative cooler; a gas outlet of the evaporative cooler is connected to a gas inlet of the dust collector; the dust collector adopts a pulse spraying high-temperature-resistant ceramic fiber filter pipe type dust collector to replace the original electrostatic precipitator in the dust removal system, but the heat loss is caused by the use of the evaporative cooler. SUMMARY

[0005] In view of the defects in the prior art, the application provides a third generation converter primary dry dedusting system.

[0006] To achieve the above object, the application is implemented by the following technical scheme:

[0007] The third generation converter primary dry dedusting system comprises a high-efficiency heat exchanger, a banana bend dust collector, a cyclone heat recovery device, a water-cooled chain conveyor, a raw coal gas pipe, a high-temperature-resistant explosion-proof super-clean dust collector, a fine ash bin, a clean coal gas pipe, a coal gas axial flow fan and a coal gas washing dehydrator.

[0008] The inlet of the high-efficiency heat exchanger is connected to the converter through a vaporization cooling flue. The raw coal gas from the converter enters the high-efficiency heat exchanger for heat exchange and recovery. A banana-bend dust collector is installed between the high-efficiency heat exchanger and the cyclone heat recovery device. A water-cooled chain conveyor is installed at the bottom of the banana-bend dust collector. The water-cooled chain conveyor is used to collect coarse ash and output it.

[0009] The cyclone heat recovery device is connected to at least one high-temperature explosion-proof ultra-clean dust collector through a raw coal gas pipe, and the outlet of the high-temperature explosion-proof ultra-clean dust collector forms clean coal gas.

[0010] The outlet of the high-temperature explosion-proof ultra-clean dust collector is connected to the clean gas pipe. The clean gas is sent to the gas switching station after passing through the gas axial flow fan and the gas washing and dehydrating device. The qualified gas is sent to the gas holder.

[0011] Furthermore, the outlet temperature of the vaporization cooling flue is 750℃~850℃. After the raw coal gas passes through the high-efficiency heat exchanger, the high-quality heat in the raw coal gas is efficiently recovered, and the temperature drops to 600℃ before entering the banana-bend dust collector. The banana-bend dust collector is equipped with multiple layers of baffles. The axial extension lines of the inlet and outlet of the banana-bend dust collector have an angle that causes the airflow direction to turn 180°, which facilitates the collection of coarse dust particles.

[0012] Furthermore, the water-cooled chain conveyor is connected to the ash discharge pipe, which is equipped with a pneumatic three-way discharge valve, a normal pneumatic double-layer flap valve, and an emergency pneumatic double-layer flap valve.

[0013] The water-cooled chain conveyor discharges ash normally to the intermediate ash silo via a pneumatic three-way unloading valve, a normal pneumatic double-layer flap valve, and a bucket elevator. The intermediate ash silo then feeds material into the converter.

[0014] The water-cooled chain conveyor discharges ash to the coarse ash silo via a pneumatic three-way unloading valve and an emergency pneumatic double-layer flap valve. The coarse ash silo is then transported out by a vacuum suction truck or pneumatically conveyed to the intermediate ash silo by a silo pump.

[0015] Furthermore, the cyclone heat recovery device includes a cyclone device and a heat recovery device. After passing through the cyclone, the raw coal gas can effectively separate coarse dust particles and enhance heat exchange. The outlet of the cyclone heat recovery device is connected to the raw coal gas pipe. The side wall of the raw coal gas pipe is connected to a nitrogen dilution pipe, which is equipped with a pneumatic shut-off valve. Nitrogen is blown in at certain points during converter operation to improve safety.

[0016] Furthermore, two or more high-temperature explosion-proof ultra-clean dust collectors can be used in combination. The inlet of each dust collector is connected to the raw coal gas pipe, the outlet of each dust collector is connected to the clean coal gas pipe, and the ash outlet of each dust collector is transported to the fine ash bin through the ash collection pipe and the bin pump. Each dust collector is equipped with an explosion relief valve, a vibrator, a heating coil and a heat preservation structure. Each high-temperature explosion-proof ultra-clean dust collector is connected to a cooling and displacement fan through a pipeline.

[0017] Furthermore, a silencer is installed on the pipeline between the gas axial flow fan and the gas scrubber / dehydrator. The gas washed and cooled by the gas scrubber / dehydrator enters the gas switching station. The qualified gas output from the gas switching station is equipped with a recovery cup valve, and the unqualified gas output from the gas switching station is equipped with a venting cup valve. The unqualified gas is sent to the venting chimney for ignition and venting.

[0018] Furthermore, a nitrogen ejector pipe and a purge pipe are provided on one side of the venting chimney. The nitrogen ejector pipe delivers medium-pressure nitrogen at a pressure ≥1.2MPa, and the purge pipe delivers low-pressure nitrogen or saturated steam at a pressure ≥0.6MPa.

[0019] The third-generation converter primary dry dust removal system of the present invention has the following beneficial effects:

[0020] 1. This invention eliminates the traditional evaporative cold water spray, solving the stubborn problem of easy scaling in evaporative cold water spray; it fully recovers the waste heat of converter gas, increasing the steam recovery amount per ton of steel by more than 50kg, making the system more energy-efficient;

[0021] 2. This invention eliminates the traditional electrostatic precipitator process and adopts a high-temperature resistant, explosion-proof, ultra-clean dust collector process, solving the system explosion venting problem caused by frequent equipment discharge, making the system safer; the outlet concentration of the high-temperature resistant, explosion-proof, ultra-clean dust collector can maintain a stable 5mg / Nm³. 3 The following system is more environmentally friendly.

[0022] 3. This invention not only solves the problem of high-quality heat not being recovered, but also the problem of easy explosion leakage in dry dust removal systems, and the problem of large fluctuations in emission concentration at the outlet of the venting chimney. It is especially suitable for dry dust removal projects of primary flue gas in converters and has broad application prospects. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0024] Figure 1 is a schematic diagram of the structure of the third-generation converter primary dry dust removal system of the present invention.

[0025] Figure 2 is a magnified view of part A in Figure 1.

[0026] Figure 3 is an enlarged view of section B in Figure 1 and a schematic diagram of the connection between the corresponding pipelines and the fine ash silo and the cooling replacement fan.

[0027] Figure 4 is a magnified view of part C in Figure 1. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings:

[0029] Example: Please refer to Figures 1 to 4. The third-generation converter primary dry dust removal system of the present invention includes a high-efficiency heat exchanger 3, a banana-bend dust collector 4, a cyclone heat recovery device 5, a water-cooled chain conveyor 6, a pneumatic three-way unloading valve 7, a normal pneumatic double-layer flap valve 8, a normal ash discharge pipe 9, a bucket elevator 10, an intermediate ash silo 11, an emergency pneumatic double-layer flap valve 12, an emergency ash discharge pipe 13, a coarse ash silo 14, a nitrogen dilution pipe 15, a pneumatic switching valve 16, and a raw coal gas pipe 17. 18. High-temperature explosion-proof ultra-clean dust collector; 19. Vibrator; 20. Heating coil; 21. Explosion relief valve; 22. Insulation structure; 23. Silo pump; 24. Pneumatic conveying pipeline (i.e., ash collection pipe); 25. Fine ash silo; 26. Cooling and displacement fan; 27. Clean gas pipe; 28. Gas axial flow fan; 29. ​​Silencer; 30. Gas scrubber and dehydrator; 31. Recovery cup valve; 33. Venting cup valve; 34. Venting chimney; 35. Nitrogen ejector pipe; and 36. Purge pipe; The outlet of converter 1 is connected to vaporization cooling flue 2.

[0030] Converter 1 and high-efficiency heat exchanger 3 are connected by vaporization cooling flue 2. Banana bend dust collector 4 is installed between high-efficiency heat exchanger 3 and cyclone heat recovery device 5. High-efficiency heat exchanger 3 is equipped with heat exchange dense tubes to remove high-quality heat from converter gas through heat exchange, thereby reducing the temperature of converter gas.

[0031] The banana-shaped dust collector 4 is equipped with multiple layers of baffles, which can increase the residence time of dust-laden converter gas within the collector and improve dust removal efficiency. A water-cooled chain conveyor 6 is installed at the bottom of the collector to transport the collected coarse ash out. The axial extension lines of the inlet and outlet of the collector have an angle that causes the airflow direction to change by 180°, and this angle is less than 60 degrees. The material of the banana-shaped dust collector 4 is stainless steel, boiler steel, or Q345R. The baffles of the collector 4 can be used in combination of two or more layers.

[0032] The cyclone heat recovery device 5 is equipped with a cyclone device and a heat recovery device; after the raw coal gas passes through the cyclone, coarse dust particles can be effectively separated and heat exchange is enhanced, which is beneficial to heat recovery.

[0033] The water-cooled chain conveyor 6 is equipped with a pneumatic three-way unloading valve 7, a normal pneumatic double-layer flap valve 8, and an emergency pneumatic double-layer flap valve 12 on the ash discharge pipe;

[0034] The water-cooled chain conveyor 6 discharges ash normally to the intermediate ash silo 11 through the pipeline, pneumatic three-way unloading valve 7, normal pneumatic double-layer flap valve 8 and bucket elevator 10. The intermediate ash silo 11 feeds material into the converter 1.

[0035] The water-cooled chain conveyor 6 discharges ash to the coarse ash silo 14 via the pneumatic three-way unloading valve 7 and the emergency pneumatic double-layer flap valve 12. The coarse ash silo 14 is transported out by a vacuum suction and discharge vehicle or pneumatically conveyed to the intermediate ash silo 11 by a silo pump.

[0036] The cyclone heat recovery device 5 and the high-temperature explosion-proof ultra-clean dust collector 18 are connected through the raw coal gas pipe 17; the cyclone heat recovery device 5 is connected to 2, 3, 4 or more high-temperature explosion-proof ultra-clean dust collectors 18, and the actual number is set according to the installation requirements. The gas outlet of each ultra-clean dust collector collects and outputs clean coal gas.

[0037] The high-temperature explosion-proof ultra-clean dust collector 18 is equipped with an explosion relief valve 21, a vibrator 19, a heating coil 20, and a heat preservation structure 22. The heat preservation structure can be a heat preservation layer made of heat preservation material.

[0038] The high-temperature explosion-proof ultra-clean dust collector 18 is equipped with a cooling and replacement fan 26. Once the dust collector is under maintenance, after the coal gas is replaced with nitrogen, the cooling and replacement fan 26 is started to blow air into the dust collector cylinder to cool down and ventilate.

[0039] The high-temperature explosion-proof ultra-clean dust collector 18 uses a silo pump 23 to pneumatically transport the collected fine ash to the fine ash silo 25; the fine ash silo 25 is equipped with a vacuum suction and discharge tanker interface;

[0040] The high-temperature explosion-proof ultra-clean dust collector 18 is equipped with a clean gas pipe 27 at its outlet. Clean gas is sent to the gas switching station after passing through the gas axial flow fan 28 and the silencer 29. Gas that passes the test passes through the recovery cup valve 30 and is washed and cooled by the gas cooling dehydrator 31 before being sent to the gas holder 32. Gas that does not pass the test passes through the venting cup valve 33 and is sent to the venting chimney 34 for ignition and venting.

[0041] The nitrogen dilution pipe 15 is equipped with a pneumatic shut-off valve 16;

[0042] The venting chimney 34 is equipped with a nitrogen ejector pipe 35 and a purge pipe 36. The nitrogen ejector pipe 35 delivers medium-pressure nitrogen with a pressure ≥1.2MPa, and the purge pipe 36 delivers low-pressure nitrogen or saturated steam with a pressure ≥0.6MPa.

[0043] The process flow of the third-generation converter primary dry dust removal system in this invention is as follows:

[0044] Converter 1 → Gasification cooling flue 2 → High-efficiency heat exchanger 3 → Banana bend separator 4 → Cyclone heat recovery device 5 → Raw coal gas pipe 17 → High temperature resistant explosion-proof ultra-clean dust collector 18 → Clean coal gas pipe 27 → Coal gas axial flow fan 28 → Silencer 29 → Coal gas scrubbing dehydrator 30 → Recovery cup valve 31 / Venting cup valve 33 → Gas holder 32 / Venting chimney 34.

[0045] In one embodiment of the present invention, the outlet temperature of the enhanced vaporization cooling flue 2 is 750℃~850℃ (generally 800℃). After the raw coal gas passes through the high-efficiency heat exchanger 3 for gas-water high-efficiency heat exchange, the high-quality heat in the raw coal gas is efficiently recovered, and the temperature drops to 600℃ before entering the banana bend dust collector 4.

[0046] When the dust-laden coal gas passes through the banana-bend dust collector 4, it first undergoes collision with multiple layers of baffles. Due to the 180° change in flow direction, under the action of gravity and centrifugal force, 35% to 45% (generally 40%) of the coarse dust particles are captured in the banana-bend dust collector 4 and fall into the water-cooled chain conveyor 6.

[0047] The water-cooled chain conveyor 6 is arranged horizontally and is interlocked with the converter 1 process, operating periodically during the smelting process.

[0048] Under normal circumstances, the coarse ash collected by the water-cooled chain conveyor 6 in this invention enters the bucket elevator 10 through the pneumatic three-way unloading valve 7 and the normal pneumatic double-layer flap valve 8 via the normal ash unloading pipe 9, and is unloaded by the bucket elevator 10 to the intermediate ash silo 11; the intermediate ash silo 11 feeds each batch of material into the converter 1, and can store coarse ash from up to two batches.

[0049] When the bucket elevator 10 is under maintenance, the coarse ash collected by the water-cooled chain conveyor 6 is discharged into the coarse ash silo 14 via the emergency ash discharge pipe 13 through the pneumatic three-way unloading valve 7 and the emergency pneumatic double-layer flap valve 12. The coarse ash silo 14 is then transported out by a vacuum suction truck or pneumatically transported into the intermediate ash silo 11 by a silo pump.

[0050] The explosion relief valve 21 on the high-temperature explosion-proof ultra-clean dust collector 18 is equipped with three-stage explosion relief. Once the pressure inside the high-temperature explosion-proof ultra-clean dust collector 18 exceeds 6500Pa, the explosion relief valve 21 will open to release pressure and protect the equipment and system safety. Once the temperature inside the dust collector is lower than 100℃, the heating coil 20 will work and stop working when it reaches 120℃.

[0051] The qualified converter gas enters the gas scrubber 30. After being cooled by saturated water spray, the temperature drops from 150°C to below 70°C, so that the gas holder 32 can store more converter gas.

[0052] In one embodiment of the present invention, during the initial stage of converter blowing and after the second lance insertion, the pneumatic shut-off valve 16 is opened and nitrogen is injected through the nitrogen dilution pipe 15 for 30 seconds to dilute the converter gas in the raw coal gas pipe 17 and prevent the content of converter gas and oxygen from reaching the explosion limit.

[0053] In this embodiment of the invention, if the system loses power or the gas axial flow fan 28 malfunctions, the pneumatic shut-off valve on the nitrogen ejector pipe 35 is opened, and nitrogen is ejected for 15 seconds to ensure system safety.

[0054] When using this invention, when the converter gas is switched from venting to recovery, the pneumatic shut-off valve on the purging pipe 36 is opened, and nitrogen or steam is purged for 30 seconds to prevent backfire in the venting chimney 34.

[0055] In one embodiment of the present invention, the cylinder diameter of the high-temperature explosion-proof ultra-clean dust collector 18 is 1.0-10m, and two or more can be used in parallel. Each dust collector inlet is connected to a raw coal gas pipe, and each dust collector outlet is connected to a clean coal gas pipe. The ash outlet of each dust collector is transported to a fine ash bin through an ash collection pipe. The filter media of the high-temperature explosion-proof ultra-clean dust collector 18 is stainless steel, fluoropolymer, or P84. The filter media of the ultra-clean dust collector can also be aramid ≥20% and aramid ≥20% or antistatic glass fiber membrane filter media, and the stainless steel conductive fiber content is ≥6%. The dust concentration at the outlet of the high-temperature explosion-proof ultra-clean dust collector 18 is ≤5mg / Nm³. 3 The third-generation converter primary dry dust removal system of this invention is applicable to converters of 50t to 400t. The converter is defined as: decarburization converter, dephosphorization converter, vanadium extraction converter, lava homogenization furnace, or stainless steel converter.

[0056] The above description is merely an embodiment of the invention's technical content. Any modifications or variations made by those skilled in the art using this invention are within the scope of the invention's claims, and are not limited to those disclosed in the embodiments.

Claims

1. A third-generation converter primary dry dust removal system, characterized in that: This includes high-efficiency heat exchangers, banana-bend dust collectors, cyclone heat recovery devices, water-cooled chain conveyors, raw coal gas pipes, high-temperature explosion-proof ultra-clean dust collectors, fine ash silos, clean coal gas pipes, coal gas axial flow fans, and coal gas scrubbing and dehydrating devices. The inlet of the high-efficiency heat exchanger is connected to the converter through a vaporization cooling flue. The raw coal gas from the converter enters the high-efficiency heat exchanger for heat exchange and recovery. A banana-bend dust collector is installed between the high-efficiency heat exchanger and the cyclone heat recovery device. A water-cooled chain conveyor is installed at the bottom of the banana-bend dust collector. The water-cooled chain conveyor is used to collect coarse ash and output it. The cyclone heat recovery device is connected to at least one high-temperature explosion-proof ultra-clean dust collector through a raw coal gas pipe, and the outlet of the high-temperature explosion-proof ultra-clean dust collector outputs clean coal gas. The outlet of the high-temperature explosion-proof ultra-clean dust collector is connected to the clean gas pipe. The clean gas is sent to the gas switching station after passing through the gas axial flow fan and the gas washing and dehydrating device. The qualified gas is sent to the gas holder.

2. The third-generation converter primary dry dust removal system according to claim 1, characterized in that: The outlet temperature of the vaporization cooling flue is 750℃~850℃. After the raw coal gas passes through the high-efficiency heat exchanger, the high-quality heat in the raw coal gas is efficiently recovered, and the temperature drops to 600℃ before entering the banana bend dust collector. The banana bend dust collector is equipped with multiple layers of baffles.

3. The third-generation converter primary dry dust removal system according to claim 1, characterized in that: The banana-shaped dust collector has an angle between the inlet and outlet axial extension lines, causing the airflow direction to turn 180°.

4. The third-generation converter primary dry dust removal system according to any one of claims 1 to 3, characterized in that: The water-cooled chain conveyor is connected to the ash discharge pipe, which is equipped with a pneumatic three-way discharge valve, a normal pneumatic double-layer flap valve, and an emergency pneumatic double-layer flap valve. The water-cooled chain conveyor discharges ash normally to the intermediate ash silo via a pneumatic three-way unloading valve, a normal pneumatic double-layer flap valve, and a bucket elevator. The intermediate ash silo then feeds material into the converter. The water-cooled chain conveyor discharges ash to the coarse ash silo via a pneumatic three-way unloading valve and an emergency pneumatic double-layer flap valve. The coarse ash silo is then transported out by a vacuum suction truck or pneumatically conveyed to the intermediate ash silo by a silo pump.

5. The third-generation converter primary dry dust removal system according to claim 1, characterized in that: The cyclone heat recovery device is equipped with a cyclone device and a heat recovery device. After passing through the cyclone, the raw coal gas can effectively separate coarse dust particles and enhance heat exchange. The outlet of the cyclone heat recovery device is connected to the raw coal gas pipe.

6. The third-generation converter primary dry dust removal system according to claim 1 or 5, characterized in that: The side wall of the raw coal gas pipe is connected to a nitrogen dilution pipe, which is equipped with a pneumatic shut-off valve.

7. The third-generation converter primary dry dust removal system according to claim 1, characterized in that: The high-temperature explosion-proof ultra-clean dust collector is equipped with two or more units for combined use. The inlet of each dust collector is connected to the raw coal gas pipe, the outlet of each dust collector is connected to the clean coal gas pipe, the ash outlet of each dust collector is transported to the fine ash bin through the ash collection pipe, each dust collector is equipped with an explosion relief valve, and each high-temperature explosion-proof ultra-clean dust collector is connected to a cooling and replacement fan through a pipeline.

8. The third-generation converter primary dry dust removal system according to claim 1 or 7, characterized in that: The high-temperature resistant explosion-proof ultra-clean dust collector is equipped with a vibrator on one side, and a heating coil is installed inside the dust collector.

9. The third-generation converter primary dry dust removal system according to claim 1, characterized in that: A silencer is installed on the pipeline between the gas axial flow fan and the gas switching station. A recovery cup valve is installed on the qualified gas pipeline output from the gas switching station, and a venting cup valve is installed on the unqualified gas pipeline output from the gas switching station.

10. The third-generation converter primary dry dust removal system according to claim 1, 2, 3, 5, 7, or 9, characterized in that: A nitrogen ejector pipe and a purge pipe are installed on one side of the venting chimney. The nitrogen ejector pipe delivers medium-pressure nitrogen at a pressure ≥1.2MPa, while the purge pipe delivers low-pressure nitrogen or saturated steam at a pressure ≥0.6MPa.

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