Blast furnace vent gas treatment system and treatment methods

Abstract

This invention proposes a blast furnace vent gas treatment system and method. The treatment system includes: a blast furnace having a shutdown gas outlet for discharging shutdown gas and an equalizing gas outlet for discharging equalizing gas; a dry dust removal device connected to the shutdown gas outlet on the blast furnace; and a spray purification and recovery device that can be switched between the shutdown gas outlet and the equalizing gas outlet on the blast furnace. The blast furnace vent gas treatment system and method of this invention can purify and recover equalizing gas and / or shutdown gas, improve the blast furnace gas recovery rate, and reduce the emission of gas and dust into the air.

Description

Technical Field

[0001] This invention relates to the technical field of blast furnace gas purification and treatment equipment, and in particular to a blast furnace vent gas treatment system and treatment method. Background Technology

[0002] During the blast furnace smelting process, after the top charge hopper is loaded, it must first be pressure-equalized to ensure the pressure inside the hopper matches that inside the furnace before charging can begin. Once charging is complete, the hopper is depressurized, thus completing one charging cycle. This is repeated approximately 300 times per day, and the gas released during this depressurization is called equalization venting gas. However, due to equipment replacement or furnace shutdown for maintenance, production needs to be halted for a shutdown operation, occurring 3-4 times per year. This process is hazardous and poses certain safety risks; therefore, the gas inside the blast furnace is usually released first, and this gas is called shutdown venting gas.

[0003] Both the pressure equalization vent gas in the furnace top charge tank and the shutdown vent gas during maintenance contain large amounts of soot, CO, and CO2. Direct release into the atmosphere would pollute the surrounding environment and waste energy. Currently, steel companies primarily focus on pressure equalization vent gas management, but with increasingly stringent environmental requirements, more and more steel companies are also paying attention to the management of shutdown vent gas.

[0004] The technology for recovering vented gas under equal pressure is relatively mature, and dry dust removal processes are commonly used, with independent equal pressure gas recovery systems configured. However, for the recovery of shut-in blast gas, due to the large volume of gas to be recovered, the existing gravity dust collector and bag filter in the blast furnace are typically used for dust removal, and a fan or ejector provides power for gas recovery. The purified gas is then buffered before being returned to the clean gas pipeline. However, this process suffers from significant resistance, affecting the recovery rate. Especially towards the end of the shut-in blast gas recovery process, to maintain positive pressure within the blast furnace, the remaining gas is naturally released without being recovered: if the gas is discharged through the blast furnace gravity dust collector and bag filter, the release time will be greatly extended; if the gas is directly discharged into the atmosphere from the blast furnace top gas vent valve, it will cause environmental pollution. In this case, a dust removal device needs to be installed at the blast furnace top vent valve for this portion of the flue gas, making the system complex.

[0005] Furthermore, in existing technologies, the two systems for equalizing venting gas recovery and shut-down venting gas recovery are mostly set up independently, resulting in relatively large investment costs and land area requirements. In addition, due to the raw materials and other factors of blast furnaces, the gas carries acidic media (sulfate ions and chloride ions), which easily combine with water vapor to corrode pipelines or equipment. Dry dust removal methods cannot solve this problem, and wet processes need to be considered to eliminate it. Summary of the Invention

[0006] The purpose of this invention is to provide a blast furnace vent gas treatment system and method to purify and recover pressure equalization gas and / or shutdown gas, improve the blast furnace gas recovery rate, and reduce the emission of gas and dust into the air.

[0007] On one hand, the present invention provides a blast furnace vent gas treatment system, which includes:

[0008] The blast furnace has a shutdown gas outlet for discharging shutdown gas and a pressure equalization gas outlet for discharging pressure equalization gas.

[0009] The dry dust removal device is connected to the shutdown gas outlet on the blast furnace.

[0010] The spray purification and recovery device can be switched to be connected to the shutdown gas outlet and the equalizing gas outlet on the blast furnace.

[0011] In a preferred embodiment of the present invention, the blast furnace is further provided with a pressure gauge for monitoring the pressure of the shut-in gas and the pressure of the equalizing gas.

[0012] In a preferred embodiment of the present invention, the blast furnace is equipped with an analyzer for monitoring the composition of the shut-in gas and the composition of the equalizing gas.

[0013] In a preferred embodiment of the present invention, the dry dust removal device is connected to the gas pipeline network through a first recovery pipeline, and the spray purification and recovery device is connected to the gas pipeline network through a second recovery pipeline.

[0014] In a preferred embodiment of the present invention, the dry dust removal device is connected to a first venting pipe, and the spray purification and recovery device is connected to a second venting pipe.

[0015] On the other hand, the present invention also provides a method for treating blast furnace vent gas using the blast furnace vent gas treatment system described above, comprising:

[0016] Pressure monitoring of the blast furnace vent gas during shutdown;

[0017] In the initial stage of the shutdown gas release, the shutdown gas is treated by a dry dust removal device and then released or recovered.

[0018] When the pressure of the idle gas is detected to drop to the first threshold, the system switches to a spray purification and recovery device to treat the idle gas and then release or recover the treated idle gas.

[0019] When the pressure of the idle gas is detected to drop to the second threshold, the idle gas that has passed through the spray purification and recovery device will be released.

[0020] In a preferred embodiment of the present invention, the method further includes:

[0021] Pressure monitoring is performed on the equalizing gas in the blast furnace vent gas.

[0022] The pressure-equalizing gas is processed by the spray purification and recovery device, and the processed pressure-equalizing gas is either released or recovered.

[0023] In a preferred embodiment of the present invention, an ejector mechanism is provided at the inlet of the spray purification and recovery device. When the pressure of the shut-off gas is detected to drop to the first threshold, high-pressure gas is introduced into the ejector mechanism. When the pressure of the shut-off gas drops to the second threshold, the introduction of high-pressure gas into the ejector mechanism is stopped.

[0024] In a preferred embodiment of the present invention, when the pressure of the equalizing gas is detected to drop to a third threshold, high-pressure gas is introduced into the ejector mechanism.

[0025] In a preferred embodiment of the present invention, the method further includes:

[0026] The pressure of the idle gas is monitored, and the composition of the idle gas is also monitored.

[0027] When the composition of the idle gas is detected to meet the recovery conditions, the idle gas that has passed through the dry dust removal device or the spray purification and recovery device is introduced into the gas pipeline network for recovery.

[0028] When the composition of the monitored idle gas does not meet the recovery conditions, the idle gas that has passed through the dry dust removal device or the spray purification and recovery device will be released.

[0029] In a preferred embodiment of the present invention, the method further includes:

[0030] The pressure of the equalizing gas is monitored, and its composition is monitored simultaneously.

[0031] When the composition of the pressure-equalizing gas is detected to meet the recovery conditions, the pressure-equalizing gas that has passed through the spray purification and recovery device is introduced into the gas pipeline network for recovery.

[0032] When the composition of the pressure-equalizing gas monitored does not meet the recovery conditions, the pressure-equalizing gas that has passed through the spray purification and recovery device will be released.

[0033] In a preferred embodiment of the present invention, the spray purification and recovery device has a spray purification mechanism and a dehydration mechanism. The idle gas or the pressure equalization gas entering the spray purification and recovery device is purified and dehydrated sequentially through the spray purification mechanism and the dehydration mechanism.

[0034] In a preferred embodiment of the present invention, the first threshold is 30 kPa to 40 kPa.

[0035] In a preferred embodiment of the present invention, the second threshold is 3 kPa to 5 kPa.

[0036] In a preferred embodiment of the present invention, the third threshold is 40 kPa to 50 kPa.

[0037] Compared with the prior art, the technical solution of the present invention has the following characteristics and advantages:

[0038] 1. The blast furnace vent gas treatment system of the present invention can simultaneously purify and recover blast furnace shutdown gas and pressure equalization gas. This avoids the emission of smoke and gas into the atmosphere, reduces environmental pollution, and brings considerable economic benefits.

[0039] 2. The blast furnace vent gas treatment method of the present invention adopts a combination of dry dust removal and wet dust removal, and a combination of natural recovery and forced recovery. It not only makes effective use of existing facilities, but also reduces blockage and greatly improves recovery efficiency.

[0040] 3. The blast furnace vent gas treatment system of the present invention can use a variety of high-pressure ejector media. Different plant areas can choose steam, nitrogen or primary pressure equalization gas according to local conditions, making it more applicable.

[0041] 4. The spray water used in this invention can be recycled, saving resources and avoiding waste of water resources; alkaline reagents can be added to the spray water to remove acidic media in the gas, reducing corrosion of gas pipelines or gas user equipment, as well as SO2 emissions. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0043] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0044] Figure 1 This is a schematic diagram of the blast furnace vented gas treatment system described in this invention;

[0045] Figure 2 This is a schematic diagram of the ejector mechanism described in this invention;

[0046] Figure 3 This is a schematic diagram of the dehydration mechanism described in this invention;

[0047] Figure 4 This is a flowchart of the blast furnace vented gas treatment method according to the present invention.

[0048] Explanation of icon numbers:

[0049] 10. Blast furnace; 11. Gas riser pipeline; 12. Shutdown gas outlet; 13. Furnace top charge tank; 14. Pressure equalizing gas outlet; 15. Gas downcomer pipeline;

[0050] 20. Dry dust collection device; 21. Gravity dust collector; 211. Shut-off valve; 22. Bag filter dust collector;

[0051] 30. Spray purification and recovery device; 31. Spray tower; 32. Ejector mechanism; 321. Ejector pipe; 322. Gas inlet; 323. Ejector gas inlet; 324. Gas outlet; 325. Nozzle; 326. Inlet section; 327. Contraction section; 328. Mixing section; 329. Expansion section; 33. Spray purification mechanism; 331. Spray head; 332. Spray circulation pipeline; 34. Dehydration mechanism; 341. Drawer-type wire mesh demister; 342. Fan-shaped demister element;

[0052] 40. First recovery pipeline; 41. Second recovery pipeline; 42. First venting pipeline; 43. Second venting pipeline; 44. First spraying pipeline; 45. Second spraying pipeline; 46. High-pressure gas pipeline; 47. Water supply pipeline;

[0053] 50. Analyzer; 51. Pressure gauge; 52. High-pressure gas source; 53. Gas pipeline network.

[0054] 60. First check valve; 61. Second check valve; 62. Clean gas recovery valve; 63. First vent valve; 64. Second vent valve; 65. Shutdown gas recovery valve; 66. Pressure equalizing gas recovery valve; 67. Shut-off valve; 68. Ash discharge valve;

[0055] 70. Drain valve; 71. Water pump; 72. Water storage tank; 73. Water supply valve; 74. Water supply tank; 75. First liquid level detector; 76. Second liquid level detector; 77. Composition detector. Detailed Implementation

[0056] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0057] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0059] Implementation Method 1:

[0060] like Figure 1 As shown, the present invention provides a blast furnace vent gas treatment system, which includes: a blast furnace 10 having a shutdown gas outlet 12 for discharging shutdown gas and an equalizing gas outlet 14 for discharging equalizing gas; a dry dust removal device 20 connected to the shutdown gas outlet 12 on the blast furnace 10; and a spray purification and recovery device 30 switchably connected to the shutdown gas outlet 12 and the equalizing gas outlet 14 on the blast furnace 10.

[0061] The blast furnace vent gas treatment system described in this invention can simultaneously purify and recover both the shutdown gas and the pressure equalization gas within the blast furnace 10. This avoids the emission of smoke and gas into the atmosphere, reduces environmental pollution, and brings considerable economic benefits.

[0062] The blast furnace vent gas treatment system described in this invention combines dry and wet dust removal methods with natural and forced recovery, which effectively utilizes existing facilities while reducing blockage and greatly improving recovery efficiency.

[0063] Specifically, such as Figure 1 As shown, the blast furnace 10 has a shutdown gas outlet 12. When the blast furnace 10 is in a shutdown period, the shutdown gas generated inside the blast furnace 10 can be discharged through the shutdown gas outlet 12. The shutdown gas outlet 12 is connected to a dry dust removal device 20 (a device that uses bag filters or other methods for dust removal) and a spray purification and recovery device 30 through pipelines, and the connection status with the two can be switched. That is, the shutdown gas outlet 12 can switch from being connected to the dry dust removal device 20 to being connected to the spray purification and recovery device 30, and vice versa.

[0064] The connection between the idle gas outlet 12 and the dry dust removal device 20 and the spray purification and recovery device 30 can be switched, so that different treatment methods can be used to treat the idle gas according to actual needs.

[0065] The blast furnace 10 also has a pressure equalization gas outlet 14. When the blast furnace 10 is in the pressure equalization venting period, the pressure equalization gas generated in the blast furnace 10 can be discharged through the pressure equalization gas outlet 14. The pressure equalization gas outlet 14 is connected to the spray purification and recovery device 30 through a pipeline, that is, the pressure equalization gas is directly treated by wet dust removal.

[0066] According to one embodiment of the present invention, such as Figure 1 As shown, the dry dust removal device 20 is connected to the gas pipeline network 53 via the first recovery pipeline 40, and the spray purification and recovery device 30 is connected to the gas pipeline network 53 via the second recovery pipeline 41. The clean gas produced after treatment by the dry dust removal device 20 or the spray purification and recovery device 30 can be recovered and reused. It is returned to the gas pipeline network 53 via the first recovery pipeline 40 and the second recovery pipeline 41 for use by gas users, thereby improving energy utilization efficiency.

[0067] Preferably, a first check valve 60 is provided on the first recovery pipeline 40, and a second check valve 61 and a clean gas recovery valve 62 are provided on the second recovery pipeline 41. The first check valve 60 and the second check valve 61 prevent clean gas from flowing back into the first recovery pipeline 40 and the second recovery pipeline 41, and the clean gas recovery valve 62 controls the opening and closing of the second recovery pipeline 41.

[0068] According to one embodiment of the present invention, such as Figure 1 As shown, the dry dust removal device 20 is connected to a first vent pipe 42, and the spray purification and recovery device 30 is connected to a second vent pipe 43. In actual dust removal operations, because the composition of the idle gas and the pressure equalization gas is unstable, even the clean gas produced after treatment by the dry dust removal device 20 or the spray purification and recovery device 30 may not meet the requirements of the gas pipeline network 53 (requiring the CO / O2 ratio in the gas to be within a certain range). Therefore, when the composition of the treated gas does not meet the requirements of the gas pipeline network 53, the clean gas is directly discharged into the atmosphere through the first vent pipe 42 and the second vent pipe 43.

[0069] Preferably, a first venting valve 63 is provided on the first venting pipe 42, and a second venting valve 64 is provided on the second venting pipe 43. The first venting valve 63 controls the opening and closing of the first venting pipe 42; the second venting valve 64 controls the opening and closing of the second venting pipe 43.

[0070] The following will provide a detailed description of the specific structures of the blast furnace 10, the dry dust removal device 20, and the spray purification and recovery device 30 in the blast furnace vent gas treatment system of the present invention, and further explain the connection relationship between the three.

[0071] First, such as Figure 1 As shown, the blast furnace 10 has a gas riser pipe 11, a shutdown gas outlet 12 is formed on the gas riser pipe 11, the blast furnace 10 has a furnace top charge tank 13, the furnace top charge tank 13 is used to add raw materials into the blast furnace 10, and a pressure equalization gas outlet 14 is formed on the side wall of the furnace top charge tank 13.

[0072] Furthermore, the idle gas outlet 12 on the gas riser 11 is connected to the dry dust removal device 20 via the gas downcomer 15; simultaneously, the idle gas outlet 12 is connected to the spray purification and recovery device 30 via the first spray pipe 44. In this embodiment, the gas downcomer 15 and the first spray pipe 44 share a section of pipe.

[0073] Better, such as Figure 1 As shown, a shutdown gas recovery valve 65 is installed on the first spray pipe 44. The shutdown gas recovery valve 65 controls the opening and closing of the first spray pipe 44.

[0074] The pressure equalization gas outlet 14 on the furnace top material tank 13 is connected to the spray purification and recovery device 30 through the second spray pipeline 45. Since the first spray pipeline 44 and the second spray pipeline 45 are connected to the spray purification and recovery device 30 at the same time, in this embodiment, the first spray pipeline 44 and the second spray pipeline 45 share a section of pipe.

[0075] Better, such as Figure 1 As shown, a pressure equalization gas recovery valve 66 is installed on the second spray pipeline 45. The opening and closing of the second spray pipeline 45 are controlled by the pressure equalization gas recovery valve 66.

[0076] According to one embodiment of the present invention, such as Figure 1 As shown, the blast furnace 10 is equipped with an analyzer 50 for monitoring the composition of the shutdown gas and the pressure equalization gas. The monitoring results of the analyzer 50 are used to determine whether the shutdown gas or the pressure equalization gas meets the conditions for being recycled into the gas pipeline 53.

[0077] Specifically, such as Figure 1 As shown, an analyzer 50 is installed in the gas riser pipeline 11 to monitor the composition of the shut-in gas; an analyzer 50 is also installed in the furnace top material tank 13 to monitor the composition of the equalizing gas. In this embodiment, the analyzer 50 is mainly used to monitor the CO / O2 ratio in the shut-in gas and the equalizing gas. When the CO / O2 ratio is found to meet the recovery conditions of the gas pipeline network 53, the clean gas recovery valve 62 is opened, the first vent valve 63 and the second vent valve 64 are closed, and the clean gas is recovered through the first recovery pipeline 40 and the second recovery pipeline 41; when the CO / O2 ratio is found to be unsuitable for the recovery conditions of the gas pipeline network 53, the first vent valve 63 and the second vent valve 64 are opened, the clean gas recovery valve 62 is closed, and the clean gas is released through the first vent pipeline 42 and the second vent pipeline 43.

[0078] According to one embodiment of the present invention, such as Figure 1 As shown, a pressure gauge 51 is installed inside the blast furnace 10 to monitor the pressure of the shut-off gas. The pressure of the shut-off gas is determined by the monitoring results of the pressure gauge 51 to determine whether the pressure meets the requirements for switching from the state connected to the dry dust removal device 20 to the state connected to the spray purification and recovery device 30.

[0079] Specifically, such as Figure 1As shown, a pressure gauge 51 is installed in the gas riser pipeline 11 to monitor the pressure of the shut-off gas. During the initial stage of shut-off gas venting, the pressure of the shut-off gas is relatively high. At this time, the shut-off gas recovery valve 65 is closed, and the first spray pipeline 44 is disconnected, connecting the gas riser pipeline 11 to the dry dust removal device 20. Dust removal is then performed on the shut-off gas using dry dust removal technology. When the shut-off gas pressure is high, using the dry dust removal device 20 to treat the shut-off gas can achieve better dust removal results and relatively higher dust removal efficiency.

[0080] As the pressure of the idle gas decreases, the efficiency of the dry dust removal device 20 is significantly reduced. Therefore, when the pressure gauge 51 detects that the pressure of the idle gas has dropped to a certain level, the idle gas recovery valve 65 is opened to open the first spray pipeline 44, and at the same time the gas downcomer pipeline 15 is cut off, switching the treatment method of the idle gas from dry dust removal to spray purification.

[0081] Preferably, when the pressure gauge 51 detects that the pressure of the shut-off gas has dropped to a first threshold, the processing method of the shut-off gas is switched. In this embodiment, the range of the first threshold is 30 kPa to 40 kPa.

[0082] According to one embodiment of the present invention, such as Figure 1 As shown, the dry dust removal device 20 has a gravity dust collector 21 and a bag filter 22 connected together. The gravity dust collector 21 is connected to the shut-off gas outlet 12 through the gas downcomer 15.

[0083] Specifically, such as Figure 1 As shown, the idle gas outlet 12 on the gas riser 11 is connected to the inlet of gravity dust collector 21 via gas downcomer 15. The outlet of gravity dust collector 21 is connected to the inlet of bag filter 22, and the outlet of bag filter 22 is connected to the first recovery pipeline 40 and the first venting pipeline 42. The idle gas passes through gravity dust collector 21 and bag filter 22 in sequence to produce clean gas. Both gravity dust collector 21 and bag filter 22 are common dust removal devices in the field and will not be described in detail here.

[0084] Furthermore, a shut-off valve 211 is provided at the inlet of the gravity dust collector 21. The gas downcomer 15 is connected to the inlet of the gravity dust collector 21 through the shut-off valve 211. The shut-off valve 211 can control the opening and closing of the gas downcomer 15.

[0085] According to one embodiment of the present invention, such as Figure 1As shown, the spray purification and recovery device 30 has an ejector mechanism 32 installed at the top of the spray tower 31, a spray purification mechanism 33 installed inside the spray tower 31, and a dehydration mechanism 34. The ejector mechanism 32 is connected to the rest gas outlet 12 through the first spray pipe 44, and the ejector mechanism 32 is connected to the pressure equalization gas outlet 14 through the second spray pipe 45.

[0086] Specifically, such as Figure 1 As shown, the main body of the spray purification and recovery device 30 is a cylindrical spray tower 31. An ejector mechanism 32 is installed at the top of the spray tower 31. The ejector mechanism 32 is connected to the first spray pipe 44 and the second spray pipe 45, respectively. The idle gas or pressure equalizing gas can enter the spray tower 31 through the ejector mechanism 32. The spray tower 31 also contains a spray purification mechanism 33 and a dehydration mechanism 34. The idle gas or pressure equalizing gas flowing out from the outlet of the ejector mechanism 32 first enters the spray purification mechanism 33 for spray purification and dust removal. After the spray purification and dust removal operation, the idle gas or pressure equalizing gas enters the dehydration mechanism 34, where small droplets entrained in the gas are removed.

[0087] Furthermore, the spray tower 31 is provided with outlets on its top and upper sidewalls. The top outlet is connected to the second venting pipe 43, and the gas after spray purification and dehydration treatment can enter the second venting pipe 43 for venting through the outlet on the top of the spray tower 31. The outlet on the sidewall is connected to the second recovery pipe 41, and the gas after spray purification and dehydration treatment can enter the second recovery pipe 41 for recovery through the outlet on the sidewall of the spray tower 31.

[0088] The detailed structures of the ejector mechanism 32, the spray purification mechanism 33, and the dehydration mechanism 34 on the spray purification device of the present invention will be further described below.

[0089] First, such as Figure 1 and Figure 2 As shown, the ejector mechanism 32 of the present invention is actually an ejector tube 321 that passes through the top of the spray tower 31. The ejector tube 321 is coaxially arranged with the spray tower 31 and is located at the center of the top of the spray tower 31.

[0090] The ejector tube 321 includes an inlet section 326, a contraction section 327, a mixing section 328, and an expansion section 329 connected in sequence; the inlet section 326, the contraction section 327, the mixing section 328, and the expansion section 329 are coaxially arranged. The free end of the inlet section 326 forms a gas inlet 322, which is connected to the first spray pipe 44. The free end of the expansion section 329 forms a gas outlet 324, which faces the spray purification mechanism 33. The idle gas from the first spray pipe 44 enters the ejector tube 321 from the gas inlet 322, passes through the inlet section 326, the contraction section 327, the mixing section 328, and the expansion section 329 in sequence, and then enters the interior of the spray tower 31 through the gas outlet 324.

[0091] Furthermore, such as Figure 1 and Figure 2 As shown, a right-angle bend nozzle is installed on the side wall of the inlet section 326 of the ejector tube 321. The end of the right-angle bend nozzle located outside the ejector tube 321 forms an ejector gas inlet 323. The ejector gas inlet 323 is connected to the high-pressure gas pipeline 46 and is used to introduce high-pressure gas into the ejector tube 321. The end of the right-angle bend nozzle located inside the ejector tube 321 forms a nozzle 325. The outlet of the nozzle 325 is located inside the constriction section 327 of the ejector tube 321, and the outlet direction of the nozzle 325 is parallel to the axial direction of the ejector tube 321.

[0092] The high-pressure gas pipeline 46 is connected to the high-pressure gas source 52, which can provide high-pressure gas to the ejector tube 321. The high-pressure gas guides the relatively low-pressure idle gas or equalizing gas into the spray tower 31.

[0093] Furthermore, a shut-off valve 67 is provided on the high-pressure gas pipeline 46, which controls the opening and closing of the high-pressure gas pipeline 46.

[0094] As described above, a pressure gauge 51 is installed in the riser pipe of blast furnace 10. The pressure gauge 51 is used to monitor the pressure of the shut-off gas and can also control the opening and closing of the high-pressure gas pipeline 46 based on the monitoring results of the pressure gauge 51.

[0095] As mentioned earlier, during the initial stage of blast furnace gas recovery, the blast furnace gas pressure is high, the gas volume is large, and the dust content is high. The pressure inside the blast furnace 10 exceeds 200 kPa, which is much higher than the pressure of the gas pipeline network 53 (10 kPa to 18 kPa). Therefore, the pressure difference between the blast furnace 10 and the gas pipeline network 53 is used to recover the blast furnace gas (that is, it is recovered through the dry dust removal device 20). The blast furnace gas recovery valve 65 is kept closed, and the shut-off valve 211 is kept open. The blast furnace gas is recovered to the gas pipeline network 53 or vented after being filtered by the gravity dust collector 21 and the bag filter 22 through the gas downcomer 15.

[0096] When the pressure monitoring in the gas riser pipeline 11 detects that the pressure of the idle gas has dropped to 30-40 kPa, the shut-off valve 211 is closed and the idle gas recovery valve 65 is opened. The idle gas is then purified in the next stage through the spray purification and recovery device 30. Simultaneously, high-pressure gas is introduced into the ejector pipe 321 through the high-pressure gas pipeline 46. The high-speed gas jet from the nozzle 325 at the contraction section 327 of the ejector pipe 321 can induce the idle gas, causing it to flow rapidly into the spray tower 31. The dust-laden idle gas rises after being washed by spray water, and after being dehydrated by the dehydration mechanism 34, it is either recovered into the gas pipeline network 53 or vented.

[0097] When the pressure monitoring in the gas riser pipeline 11 detects that the pressure of the shut-off gas has dropped to 3KPa~5KPa, the shut-off gas is in the final stage of recovery. In order to ensure that the positive pressure is maintained in the blast furnace 10, the remaining shut-off gas will not be recovered. At this time, the shut-off valve 67 is closed to stop the high-pressure gas from entering the phase ejector pipe 321. At the same time, the second vent valve 64 is opened and the clean gas recovery valve 62 is closed. After being sprayed and purified by the spray tower 31, the shut-off gas is naturally released into the air at a high point.

[0098] According to one embodiment of the present invention, such as Figure 1 As shown, a pressure gauge 51 for monitoring the pressure of the equalizing gas is also installed in the furnace top charge tank 13 connected to the blast furnace 10. The pressure of the equalizing gas is monitored by the pressure gauge 51, and the opening and closing of the high-pressure gas pipeline 46 is controlled according to the monitoring results of the pressure gauge 51.

[0099] As mentioned above, for the recovery of pressure equalization gas, the gas recovery time should be shortened as much as possible, and the recovery time should be guaranteed to be within 12 seconds. Otherwise, it will affect the entire process of charging and equalizing pressure in the furnace top tank 13. Since the amount of pressure equalization gas is relatively small, the purification and recovery method of spray tower 31 is directly adopted.

[0100] In the initial stage of recovery, the pressure of the equalizing gas is much higher than that of the gas pipeline 53. Therefore, natural recovery is adopted. The equalizing gas recovery valve 66 and the clean gas recovery valve 62 are opened, and the spray purification and recovery device 30 also starts to work at the same time. At this time, it is not necessary to introduce high-pressure gas into the ejector tube 321 through the high-pressure gas pipeline 46.

[0101] When the pressure gauge 51 in the furnace top material tank 13 detects that the pressure of the equalizing gas has dropped to 40KPa~50KPa, the shut-off valve 67 is opened, and high-pressure gas is introduced into the ejector tube 321 through the high-pressure gas pipeline 46. The high-speed airflow ejected by the nozzle 325 in the contraction section 327 of the ejector tube 321 can induce the equalizing gas, which will quickly enter the equalizing gas flow. The equalizing gas is forced to be recovered and enters the spray tower 31. After spray purification and dehydration treatment, it enters the gas pipeline network 53 or is released.

[0102] When the pressure gauge 51 in the furnace top material tank 13 detects that the pressure of the equalizing gas has dropped to 3KPa~5KPa, one equalizing gas recovery action is completed. At this time, all valves associated with the equalizing gas recovery are closed, and the process waits for the next equalizing gas recovery process.

[0103] Secondly, such as Figure 1 As shown, the spray purification mechanism 33 has multiple spray heads 331 installed on the side wall of the spray tower 31, and the multiple spray heads 331 are connected to the spray circulation pipeline 332.

[0104] Specifically, multiple spray heads 331 are installed on the side wall of the spray tower 31 and surround the gas outlet 324 of the ejector pipe 321. The idle gas or pressure equalization gas flowing out through the gas outlet 324 of the ejector pipe 321 can directly enter the spray purification area formed by a large number of spray heads 331.

[0105] A water pump 71 and a water storage tank 72 are provided on the spray circulation pipeline 332 connected to the spray head 331. The water storage tank 72 serves as the water source for spray purification, and the water pump 71 provides power to the spray circulation pipeline 332.

[0106] Furthermore, a water outlet is provided on the side wall at the bottom of the spray tower 31. This water outlet is connected to the water storage tank 72 through a pipe, and the cleaning liquid accumulated in the spray tower 31 can flow back into the water storage tank 72 through this pipe.

[0107] Preferably, a drain valve 70 is installed on the pipeline between the spray tower 31 and the water storage tank 72, and a first level detector 75 for monitoring the water level of the cleaning fluid is installed at the bottom of the spray tower 31. When the first level detector 75 detects that the water level has reached the set high point, the drain valve 70 is opened, and the cleaning fluid flows back into the water storage tank 72. After secondary sedimentation and pressurization by the water pump 71, it enters the spray head 331 for spray purification operation and is used for spray purification again. When the first level detector 75 detects that the water level has reached the set low point, the drain valve 70 is closed to prevent gas leakage.

[0108] According to one embodiment of the present invention, such as Figure 1 As shown, the water storage tank 72 is equipped with a component analyzer 77 for monitoring the composition of the water. and Cl-1 If necessary, alkaline reagents are added to the water storage tank 72 to neutralize and condition the cleaning solution. This reduces acidic corrosion to the equipment and allows the spraying process to desulfurize and dechlorinate the coal gas, meeting environmental protection requirements.

[0109] According to one embodiment of the present invention, such as Figure 1 As shown, the water storage tank 72 is also equipped with a second liquid level detector 76, which is used to monitor the water level of the cleaning fluid in the water storage tank 72. At the same time, the water storage tank is also connected to a water replenishment pipeline 47, which is equipped with a water replenishment valve 73 and a water replenishment tank 74. When the second liquid level detector 76 detects that the liquid level of the cleaning fluid in the water storage tank 72 has dropped to a set low point, the water replenishment valve 73 is opened, and the cleaning fluid is replenished into the water storage tank 72 through the water replenishment tank 74.

[0110] According to one embodiment of the present invention, the water pump 71 is an acid and alkali resistant corrosion-resistant water pump 71, and should also have wear-resistant characteristics to ensure service life.

[0111] Finally, as Figure 1 and Figure 3 As shown, the dehydration mechanism 34 is a drawer-type wire mesh demister 341 made of metal wire mesh. The drawer-type wire mesh demister 341 consists of multiple fan-shaped demister elements 342, each of which is made of metal wire mesh. When gas carrying mist droplets passes through the metal wire mesh, the droplets come into contact with the mesh and adhere to its surface. Due to the wettability of the filaments, the surface tension of the liquid, and the capillary action of the filaments, the droplets grow larger and larger, eventually falling off due to gravity, thus effectively removing the mist droplets entrained in the gas.

[0112] According to one embodiment of the present invention, such as Figure 1 As shown, the bottom of the spray tower 31 is equipped with an ash discharge valve 68. Dust in the shut-off gas or equalizing gas combines with the sprayed water mist and falls to the bottom of the spray tower 31 under gravity, where it settles. The ash discharge valve 68 needs to be opened periodically to discharge the dust settled at the bottom of the spray tower 31.

[0113] Implementation Method Two:

[0114] like Figure 1 and Figure 4As shown, the present invention also provides a method for treating blast furnace vent gas using the blast furnace vent gas treatment system described in Embodiment 1, comprising: monitoring the pressure of the shut-in blast gas in the blast furnace vent gas; in the initial stage of shut-in vent gas treatment, treating the shut-in blast gas with a dry dust removal device 20 and releasing or recovering the treated shut-in blast gas; when the pressure of the shut-in blast gas is detected to drop to a first threshold, switching to a spray purification and recovery device 30 to treat the shut-in blast gas and releasing or recovering the treated shut-in blast gas; when the pressure of the shut-in blast gas is detected to drop to a second threshold, releasing the shut-in blast gas that has passed through the spray purification and recovery device 30.

[0115] Specifically, the pressure of the shut-off gas is monitored by a pressure gauge 51 installed in the gas riser pipeline 11. In the initial stage of shut-off venting, the shut-off gas pressure is high, the volume is large, and the dust content is high. The pressure inside the blast furnace 10 exceeds 200 kPa, which is much higher than the pressure in the gas pipeline network 53 (10 kPa to 18 kPa). Therefore, the shut-off gas is recovered using the pressure difference between the blast furnace 10 and the gas pipeline network 53 (i.e., recovered through the dry dust removal device 20). The shut-off gas recovery valve 65 remains closed, and the shut-off valve 211 on the gravity dust collector 21 remains open. The shut-off gas is recovered to the gas pipeline network 53 or vented after being dedusted by the gravity dust collector 21 and the bag filter 22 via the gas downcomer pipeline 15.

[0116] When the pressure monitoring in the gas riser pipeline 11 detects that the pressure of the idle gas has dropped to 30-40 kPa, the efficiency of processing it using the pressure difference through the dry dust collector 20 is significantly reduced due to the relatively low pressure. Therefore, the process is switched to the spray purification and recovery device 30. The shut-off valve 211 on the gravity dust collector 21 is closed, and the idle gas recovery valve 65 is opened, allowing the idle gas to undergo the next stage of purification treatment through the spray purification and recovery device 30.

[0117] Preferably, the first threshold is 30 kPa to 40 kPa; the second threshold is 3 kPa to 5 kPa.

[0118] Furthermore, the spray purification and recovery device 30 has a spray purification mechanism 33 and a dehydration mechanism 34. The idle gas entering the spray purification and recovery device 30 is purified and dehydrated by passing through the spray purification mechanism 33 and the dehydration mechanism 34 in sequence. The clean gas generated after purification and dehydration is recovered to the gas pipeline network 53 or released.

[0119] According to one embodiment of the present invention, the spray purification and recovery device 30 is provided with an ejector mechanism 32 at the inlet. When the pressure of the shut-off gas is detected to drop to a first threshold, high-pressure gas is introduced into the ejector mechanism 32. When the pressure of the shut-off gas drops to a second threshold, the introduction of high-pressure gas into the ejector mechanism 32 is stopped.

[0120] When recovering idle gas through the spray purification and recovery equipment, the pressure of the idle gas is low at this time. Therefore, high-pressure gas needs to be introduced into the ejector mechanism 32 to induce an ejection effect on the idle gas. Therefore, when the idle gas pressure drops to 30KPa~40KPa (first threshold), the shut-off valve 67 on the high-pressure gas pipeline 46 is opened while switching the dust removal mode. The high-pressure gas source 52 introduces high-pressure gas into the right-angle bend nozzle. The high-speed airflow ejected from the nozzle 325 of the right-angle bend nozzle at the contraction section 327 of the ejector pipe 321 can induce an ejection effect on the idle gas, causing the idle gas to flow in quickly. The idle gas is forcibly recovered into the spray tower 31. The dust-laden idle gas rises after being washed by spray water, and after being dehydrated by the dehydration mechanism 34, it is recovered into the gas pipeline network 53 or vented.

[0121] Furthermore, when the pressure monitoring in the gas riser pipeline 11 detects that the pressure of the shut-off gas has dropped to 3KPa~5KPa (second threshold), the shut-off gas is in the final stage of recovery. In order to ensure that the positive pressure is maintained in the blast furnace 10, the remaining shut-off gas is not recovered. At this time, the shut-off valve 67 is closed to stop the introduction of high-pressure gas into the ejector pipe 321, and the second vent valve 64 is opened at the same time. The clean gas recovery valve 62 is closed. After being sprayed and purified by the spray tower 31, the shut-off gas is naturally released into the air at a high point.

[0122] According to one embodiment of the present invention, such as Figure 1 and Figure 4 As shown, the blast furnace vented gas treatment method also includes: monitoring the pressure of the vented gas and monitoring its composition; when the composition of the vented gas meets the recovery conditions, the vented gas that has passed through the dry dust removal device 20 or the spray purification and recovery device 30 is introduced into the gas pipeline network 53 for recovery; when the composition of the vented gas does not meet the recovery conditions, the vented gas that has passed through the dry dust removal device 20 or the spray purification and recovery device 30 is vented.

[0123] Specifically, the composition of the idle gas is monitored by an analyzer 50 installed in the gas riser pipeline 11. The analyzer 50 is mainly used to monitor the CO / O2 ratio in the idle gas. When the CO / O2 ratio meets the recovery conditions of the gas pipeline network 53, the first vent valve 63 is closed, and the clean gas is recovered through the first recovery pipeline 40; when the CO / O2 ratio does not meet the recovery conditions of the gas pipeline network 53, the first vent valve 63 is opened, and the clean gas is released through the first vent pipeline 42.

[0124] According to one embodiment of the present invention, such as Figure 1 and Figure 4As shown, the method for treating blast furnace vented gas further includes: monitoring the pressure of the pressure equalizing gas in the blast furnace vented gas; treating the pressure equalizing gas through a spray purification and recovery device 30 and releasing or recovering the treated pressure equalizing gas.

[0125] Specifically, the pressure of the equalizing gas is monitored by a pressure gauge 51 installed in the furnace top material tank 13. For the recovery of the equalizing gas, the gas recovery time should be shortened as much as possible, and the recovery time should be guaranteed to be within 12 seconds. Otherwise, it will affect the entire process of charging and equalizing the pressure in the furnace top material tank 13. Moreover, the amount of equalizing gas is relatively small, so the purification and recovery method of the spray tower 31 is directly adopted.

[0126] Furthermore, the spray purification and recovery device 30 has a spray purification mechanism 33 and a dehydration mechanism 34. The pressure-equalizing coal gas entering the spray purification and recovery device 30 is purified and dehydrated sequentially through the spray purification mechanism 33 and the dehydration mechanism 34. The clean coal gas generated after purification and dehydration is recovered to the coal gas pipeline network 53 or released.

[0127] According to one embodiment of the present invention, such as Figure 1 and Figure 4 As shown, when the pressure of the equalizing gas drops to the third threshold, high-pressure gas is introduced into the ejector mechanism 32.

[0128] When recovering the equalizing gas through the spray purification device, although the venting process is relatively short, the pressure of the equalizing gas still undergoes a change. When the pressure is low, high-pressure gas needs to be introduced into the ejector mechanism 32 to induce the equalizing gas. Therefore, when the pressure gauge 51 in the furnace top material tank 13 detects that the pressure of the equalizing gas has dropped to the third threshold, the shut-off valve 67 on the high-pressure gas pipeline 46 is opened, and high-pressure gas is introduced into the ejector pipe 321 through the high-pressure gas source 52. The high-speed airflow ejected by the nozzle 325 in the contraction section 327 of the ejector pipe 321 can induce the equalizing gas, causing the equalizing gas flow to enter rapidly. The equalizing gas is forcibly recovered into the spray tower 31, and after spray purification and dehydration treatment, it enters the gas pipeline network 53 or is vented.

[0129] Ideally, the third threshold is 40 kPa to 50 kPa.

[0130] According to one embodiment of the present invention, such as Figure 1 and Figure 4 As shown, the blast furnace vented gas treatment method also includes: monitoring the pressure of the equalizing gas while monitoring its composition; when the composition of the equalizing gas meets the recovery conditions, the equalizing gas that has passed through the spray purification and recovery device 30 is introduced into the gas pipeline network 53 for recovery; when the composition of the equalizing gas does not meet the recovery conditions, the equalizing gas that has passed through the spray purification and recovery device 30 is vented.

[0131] Specifically, the composition of the pressure-equalizing gas is monitored by an analyzer 50 installed in the furnace top hopper 13. The analyzer 50 is mainly used to monitor the CO / O2 ratio in the pressure-equalizing gas. When the CO / O2 ratio is found to meet the recovery conditions of the gas pipeline 53, the clean gas recovery valve 62 is opened and the second vent valve 64 is closed, and the clean gas is recovered through the second recovery pipeline 41. When the CO / O2 ratio is found to be unsuitable for the recovery conditions of the gas pipeline 53, the second vent valve 64 is opened and the clean gas recovery valve 62 is closed, and the clean gas is released through the second vent pipeline 43.

[0132] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for treating blast furnace vented gas using a blast furnace vented gas treatment system, characterized in that, The blast furnace vent gas treatment system includes: The blast furnace has a shut-off gas outlet for discharging shut-off gas and an equalizing gas outlet for discharging equalizing gas; the blast furnace is also equipped with a pressure gauge for monitoring the pressure of the shut-off gas and the pressure of the equalizing gas. The dry dust removal device is connected to the shutdown gas outlet on the blast furnace. The spray purification and recovery device can be switched to be connected to the shutdown gas outlet and the equalizing gas outlet on the blast furnace; the inlet of the spray purification and recovery device is equipped with an ejector mechanism; The blast furnace vent gas treatment system described above includes the following steps: Pressure monitoring of the blast furnace vent gas during shutdown; In the initial stage of the shutdown gas release, the shutdown gas is treated by the dry dust removal device and the treated shutdown gas is released or recovered. When the pressure of the idle gas is detected to drop to the first threshold, high-pressure gas is introduced into the ejector mechanism, and the spray purification and recovery device is switched to process the idle gas and release or recover the processed idle gas. When the pressure of the idle gas is detected to drop to the second threshold, the high-pressure gas is stopped from being introduced into the ejector mechanism, and the idle gas that has passed through the spray purification and recovery device is released. The first threshold is 30 kPa to 40 kPa; The second threshold is 3kPa to 5kPa.

2. The method for treating blast furnace vented gas according to claim 1, characterized in that, The blast furnace is equipped with an analyzer for monitoring the composition of the shut-in gas and the composition of the equalizing gas.

3. The method for treating blast furnace vented gas according to claim 1, characterized in that, The dry dust removal device is connected to the gas pipeline network through a first recovery pipeline, and the spray purification and recovery device is connected to the gas pipeline network through a second recovery pipeline.

4. The method for treating blast furnace vented gas according to claim 1 or 3, characterized in that, The dry dust removal device is connected to a first venting pipe, and the spray purification and recovery device is connected to a second venting pipe.

5. The method for treating blast furnace vented gas according to claim 1, characterized in that, The method further includes: Pressure monitoring is performed on the equalizing gas in the blast furnace vent gas. The pressure-equalizing gas is processed by the spray purification and recovery device, and the processed pressure-equalizing gas is either released or recovered.

6. The method for treating blast furnace vented gas according to claim 5, characterized in that, When the pressure of the equalizing gas drops to the third threshold, high-pressure gas is introduced into the ejector mechanism.

7. The method for treating blast furnace vented gas according to claim 1, 5, or 6, characterized in that, The method further includes: The pressure of the idle gas is monitored, and the composition of the idle gas is also monitored. When the composition of the idle gas is detected to meet the recovery conditions, the idle gas that has passed through the dry dust removal device or the spray purification and recovery device is introduced into the gas pipeline network for recovery. When the composition of the monitored idle gas does not meet the recovery conditions, the idle gas that has passed through the dry dust removal device or the spray purification and recovery device will be released.

8. The method for treating blast furnace vented gas according to claim 6, characterized in that, The method further includes: The pressure of the equalizing gas is monitored, and its composition is monitored simultaneously. When the composition of the pressure-equalizing gas is detected to meet the recovery conditions, the pressure-equalizing gas that has passed through the spray purification and recovery device is introduced into the gas pipeline network for recovery. When the composition of the pressure-equalizing gas monitored does not meet the recovery conditions, the pressure-equalizing gas that has passed through the spray purification and recovery device will be released.

9. The method for treating blast furnace vented gas according to claim 1 or 6, characterized in that, The spray purification and recovery device has a spray purification mechanism and a dehydration mechanism. The idle gas or the pressure equalization gas entering the spray purification and recovery device is purified and dehydrated sequentially through the spray purification mechanism and the dehydration mechanism.

10. The method for treating blast furnace vented gas according to claim 6, characterized in that, The third threshold is 40 kPa to 50 kPa.

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