Third-generation converter gas dry dedusting system

Abstract

The present invention relates to a third-generation converter gas dry dedusting system, comprising a high-efficiency heat exchanger, a banana bend dust collector, a swirl heat recovery device, a water-cooled drum, a raw gas pipe, a high-temperature-resistant explosion-proof ultra-clean dust collector, a fine ash hopper, a clean gas pipe, a gas axial fan, and a gas cooler and dehydrator, wherein the banana bend dust collector is arranged between the high-efficiency heat exchanger and the swirl heat recovery device, and the swirl heat recovery device is connected to the high-temperature-resistant explosion-proof ultra-clean dust collector by means of the raw gas pipe. The clean gas pipe is arranged at an outlet of the high-temperature-resistant explosion-proof ultra-clean dust collector, and clean gas passes through the gas axial fan and is sent to a gas switching station. Compliant gas is scrubbed and cooled by means of the gas cooler and dehydrator and then sent to a gas holder; and non-compliant gas is sent to a flare stack for ignition and flaring. The present invention not only solves the problem of failure to recover high-quality heat, but also solves the problem of explosion vulnerability in dry dedusting systems, and has broad application prospects.

Description

A third-generation dry dust removal system for converter gas Technical Field

[0001] This invention discloses a third-generation dry dust removal system for converter gas, belonging to the technical field of environmental dust removal equipment. Background Technology

[0002] With the increasing demand for Class A emission standards and ultra-low emission requirements from steel enterprises, most newly built and renovated converters adopt dry dust removal systems. Currently, common dry dust removal systems mainly include the first-generation converter gas dry dust removal systems LT method and DDS method, as well as improved second-generation converter gas dry dust removal systems, including those with coal cooling pre-cooling, dual coal cooling, coal cooling + metal filter cartridges, and wet electrostatic precipitators installed after the electrostatic precipitator.

[0003] The existing dry dust removal systems for converter gas have the following main problems: First, the temperature is reduced directly from 900℃ to around 250℃ by spraying water mist through an evaporative cooler, resulting in a waste of this high-quality heat that is not recovered. Second, the use of electrostatic precipitators is problematic because the continuous discharge of the high-voltage power supply can easily cause an explosion if the mixed gas components inside the precipitator reach their explosive limits, damaging the equipment within the system and affecting the dust removal efficiency. In addition, the varying degrees of discharge from the high-voltage power supply can cause significant fluctuations in voltage and current between the electrodes and plates, affecting the dust removal efficiency of the electrostatic precipitator and leading to substantial fluctuations in the dust emission concentration at the chimney outlet. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a third-generation dry dust removal system for converter gas.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] A third-generation converter gas dry dust removal system includes a high-efficiency heat exchanger, a banana-bend dust collector, a cyclone heat recovery device, a water-cooled drum, raw gas pipes, a high-temperature explosion-proof ultra-clean dust collector, a fine ash bin, clean gas pipes, a gas axial flow fan, and a gas cooling dehydrator.

[0007] 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 drum is installed at the bottom of the banana-bend dust collector. The water-cooled drum is used to collect coarse ash and transport it out.

[0008] The cyclone heat recovery device is connected to the high-temperature explosion-proof ultra-clean dust collector through the raw coal gas pipe. The outlet of the high-temperature explosion-proof ultra-clean dust collector forms clean coal gas, and the ash outlet of the high-temperature explosion-proof ultra-clean dust collector uses a silo pump to forcefully transport fine ash into the fine ash silo.

[0009] 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 by the gas axial flow fan. The qualified gas is sent to the gas holder after being washed and cooled by the gas cooling dehydrator. The unqualified gas is sent to the venting chimney for ignition and venting.

[0010] 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, and 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°.

[0011] Furthermore, the water-cooled roller 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.

[0012] The water-cooled drum discharges ash 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.

[0013] The water-cooled roller discharges ash into 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.

[0014] Furthermore, the cyclone heat recovery device 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 can be enhanced. The outlet of the cyclone heat recovery device is connected to the raw coal gas pipe, and the side wall of the raw coal gas pipe is connected to the nitrogen dilution pipe. The nitrogen dilution pipe is equipped with a pneumatic shut-off valve.

[0015] 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. 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.

[0016] Furthermore, 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.

[0017] 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.

[0018] The third-generation dry dust removal system for converter gas of the present invention has the following beneficial effects:

[0019] 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;

[0020] 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.

[0021] 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 suitable for dry dust removal projects of primary flue gas in converters and has broad application prospects. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0023] Figure 1 is a schematic diagram of the structure of the third-generation converter gas dry dust removal system of the present invention.

[0024] Figure 2 is a magnified view of part A in Figure 1.

[0025] Figure 3 is a magnified view of part B in Figure 1, showing the connection between the fine ash silo and the cooling displacement fan.

[0026] Figure 4 is a magnified view of part C in Figure 1. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings:

[0028] Example: Please refer to Figures 1 to 4. The third-generation converter gas 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 drum 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, a raw coal gas pipe 17, a high-temperature resistant explosion-proof ultra-clean dust collector 18, and a vibrator 1. 9. Heating coil 20. Explosion relief valve 21. Insulation structure 22. Silo pump 23. Pneumatic conveying pipeline (i.e., ash collection pipe) 24. Fine ash silo 25. Cooling and displacement fan 26. Clean gas pipe 27. Gas axial flow fan 28. Silencer 29. Recovery cup valve 30. Gas cooling dehydrator 31. Venting cup valve 33. Venting chimney 34. Nitrogen ejector pipe 35. and purge pipe 36; The outlet of converter 1 is connected to vaporization cooling flue 2. The converter is defined as: decarburization converter or dephosphorization converter or vanadium extraction converter or lava homogenization furnace or stainless steel converter;

[0029] 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.

[0030] The banana-shaped dust collector 4 is equipped with multiple layers of baffles, which can increase the residence time of dust-laden converter gas in the banana-shaped dust collector 4 and improve the dust removal efficiency; the bottom of the banana-shaped dust collector 4 is equipped with a water-cooled drum 6 to transport the collected coarse ash out; the axial extension lines of the inlet and outlet of the banana-shaped dust collector have an angle that causes the airflow direction to turn 180°, and the above 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 banana-shaped dust collector 4 can be used in combination of two or more layers;

[0031] 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.

[0032] The water-cooled drum 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.

[0033] The water-cooled roller 6 discharges ash normally to the intermediate ash silo 11 via the pneumatic three-way unloading valve 7, the normal pneumatic double-layer flap valve 8 and the bucket elevator 10. The intermediate ash silo 11 then feeds material into the converter 1.

[0034] The water-cooled roller 6 discharges ash into 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 transported into the intermediate ash silo 11 by a silo pump.

[0035] The cyclone heat recovery device 5 and the high-temperature explosion-proof ultra-clean dust collector 18 are connected by the raw coal gas pipe 17.

[0036] 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 an insulation structure 22, which can be an insulation layer made of insulation material.

[0037] 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.

[0038] 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;

[0039] 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.

[0040] The nitrogen dilution pipe 15 is equipped with a pneumatic shut-off valve 16;

[0041] 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.

[0042] The process flow of the third-generation converter gas dry dust removal system in this invention is as follows:

[0043] Converter 1 → Gasification cooling flue 2 → High-efficiency heat exchanger 3 → Banana bend dust collector 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 → Recovery cup valve 30 / Venting cup valve 33 → Coal gas cooling dehydrator 31 / Venting chimney 34 → Gas holder 32.

[0044] 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.

[0045] 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 drum 6.

[0046] The water-cooled drum 6 is arranged horizontally and is interlocked with the converter 1 process, operating periodically during smelting.

[0047] Under normal circumstances, the coarse ash collected by the water-cooled drum 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.

[0048] When the bucket elevator 10 is under maintenance, the coarse ash collected by the water-cooled drum 6 is discharged into the coarse ash silo 14 via the emergency ash discharge pipe 13 through the pneumatic three-way discharge 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.

[0049] 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℃.

[0050] The qualified converter gas enters the gas cooling and dehydrating unit 31. 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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, with aramid fiber ≥20% and aramid fiber ≥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 dry dust removal system for converter gas of this invention is suitable for converters ranging from 50t to 400t.

[0055] 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 dry dust removal system for converter gas, characterized in that: This includes high-efficiency heat exchangers, banana-bend dust collectors, cyclone heat recovery devices, water-cooled drums, raw coal gas pipes, high-temperature explosion-proof ultra-clean dust collectors, fine ash bins, clean coal gas pipes, coal gas axial flow fans, and coal gas cooling dehydrators. 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 drum is installed at the bottom of the banana-bend dust collector. The water-cooled drum is used to collect coarse ash and transport it out. The cyclone heat recovery device is connected to the high-temperature explosion-proof ultra-clean dust collector through the raw coal gas pipe. The outlet of the high-temperature explosion-proof ultra-clean dust collector forms clean coal gas, and the ash outlet of the high-temperature explosion-proof ultra-clean dust collector uses a silo pump to forcefully transport fine ash into the fine ash silo. 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 by the gas axial flow fan. The qualified gas is sent to the gas holder after being washed and cooled by the gas cooling dehydrator. The unqualified gas is sent to the venting chimney for ignition and venting.

2. The third-generation converter gas 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 gas 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 gas dry dust removal system according to any one of claims 1 to 3, characterized in that: The water-cooled drum 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 drum discharges ash 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 roller discharges ash into 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 gas 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 gas 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 gas dry dust removal system according to claim 1, characterized in that: High-temperature explosion-proof ultra-clean dust collectors can be used in combination of two or more. 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 dry dust removal system for converter gas 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 gas 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 gas 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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