Method for cleaning and pre-coating a blast furnace water system by flushing

Abstract

The application discloses a method for flushing and cleaning pre-film of a blast furnace water system, and comprises the following steps: S1: adding a penetrating agent OG-702, an oil removing agent OG-603 and a defoaming agent into the water system, and inputting water flow into a blast furnace pipeline from the top of the blast furnace pipeline downward through a backflush bypass, so as to backflush and flush the blast furnace pipeline, and the flushing is circular and lasts for 3-5 hours; the turbidity is monitored, a turbidity curve is drawn, and the flushing is stopped when an inflection point appears on the turbidity curve; S2: after S1, adding a stripping agent OG-501, a cleaning corrosion inhibitor OG-206, a complex cleaning agent OG-602, an organic cleaning agent OG-601 and a defoaming agent into the water system, and circularly cleaning for 15-24 hours; water flow is input into the blast furnace pipeline from the top of the blast furnace pipeline downward through the backflush bypass, so as to backflush and flush the blast furnace pipeline, and the cleaning lasts for 15-24 hours; the iron ion index is monitored, an iron ion curve is drawn, and the cleaning is stopped when an inflection point appears on the iron ion curve. The backflushing from top to bottom can effectively discharge dirt such as water scale, and can conveniently flush the blast furnace pipeline.

Description

Technical Field

[0001] This invention relates to the field of steel production, and in particular to a method for pre-filming and cleaning a blast furnace water system. Background Technology

[0002] Existing blast furnace water systems mostly supply water from bottom to top, such as Figure 1 As shown, the water system is put into use directly after a single flush before use, and the flushing method, from bottom to top, still leaves foreign matter inside the cooling wall tubes. During production, no further flushing, cleaning, or pre-filming is performed. The cooling walls are used for extended periods without cleaning, resulting in scale buildup inside the tubes that reduces thermal performance. This leads to a shortened furnace lifespan, a decreased blast furnace utilization coefficient, and frequent future maintenance or replacement of the cooling walls. Summary of the Invention

[0003] The purpose of this invention is to provide a method for flushing, cleaning, and pre-filming a blast furnace water system. The method uses a top-down backflushing approach to effectively remove scale and other contaminants. By setting up a backflushing bypass, the blast furnace pipeline can be flushed conveniently, which is beneficial for regular cleaning of the blast furnace pipeline during production.

[0004] A method for flushing, cleaning, and pre-filming a blast furnace water system, wherein the blast furnace water system is equipped with a backflushing bypass, the inlet of which is connected to the outlet of the main supply pump, and the outlet of which is connected to the return water main. The method includes: S1: adding penetrant OG-702, degreasing agent OG-603, and defoamer to the water system; conveying water through the backflushing bypass from the top of the blast furnace pipeline downwards to backflush the blast furnace pipeline; circulating the flushing for 3-5 hours; monitoring the turbidity; and plotting a turbidity curve. S1: When the turbidity curve shows an inflection point, stop flushing; S2: After S1, add stripping agent OG-501, cleaning corrosion inhibitor OG-206, complexing cleaning agent OG-602, organic cleaning agent OG-601, and defoamer to the water system, and circulate for 15-24 hours. The conveyed water flows through the backflushing bypass and enters the blast furnace pipeline from the top downwards to backflush the blast furnace pipeline. Circulate for 15-24 hours, monitor the iron ion index, and draw the iron ion curve. Stop flushing when the iron ion curve shows an inflection point.

[0005] In one embodiment, in the blast furnace water system, a first shut-off device and a blowdown valve are provided between the backflushing bypass inlet and the bottom inlet of the blast furnace. The first shut-off device is located between the blowdown valve and the inlet of the backflushing bypass. The method for flushing, cleaning, and pre-filming the blast furnace water system further includes: providing a second shut-off device between the outlet of the backflushing bypass and the inlet of the water station; before S1, S0 is performed: the blowdown valve is opened, and water from the water station is used to backflush the pipelines inside the blast furnace, and the wastewater flowing from the bottom of the blast furnace pipelines is discharged from the blowdown valve.

[0006] In one embodiment, in the blast furnace water system, the outlet of the blowdown valve is connected to the return water main pipe, and the method for flushing and cleaning the blast furnace water system further includes: during S1 and S2, the water flowing out of the blast furnace pipeline flows from the blowdown valve into the return water main pipe for circulating flushing.

[0007] In one embodiment, the method for flushing, cleaning, and pre-filming the blast furnace water system further includes: in S1 or S2, performing pump switching operation cleaning on the pump intervals in the water system.

[0008] In one embodiment, the method for flushing and cleaning pre-filming the blast furnace water system further includes: in S1, replacing part of the water according to the turbidity of the flushed water.

[0009] In one embodiment, the method for flushing and cleaning the pre-filming of the blast furnace water system further includes: after S1 and before S2, draining the water in the blast furnace pipeline and refilling it with water.

[0010] In one embodiment, the method for flushing and cleaning the blast furnace water system for pre-filming further includes: performing pre-filming treatment S3 after backflushing and cleaning: adding pre-filming agent OG-308A, pre-filming aid OG-308B, and copper corrosion inhibitor OG-205 into the water system and performing circulating pre-filming for 48 to 60 hours.

[0011] In one embodiment, the method for flushing and cleaning pre-filming the blast furnace water system further includes: in S3, the water flow direction is the same as the water flow direction of the backwash cleaning.

[0012] In one embodiment, the method for flushing and cleaning the blast furnace water system for pre-filming further includes: after S3, performing S4: replacing with demineralized water, gradually replacing with demineralized water at a supply capacity of approximately 50 m^3 / h until the system water hardness is ≤15 mg / L and turbidity is ≤5 NTU, adding a protective film agent during the replacement process, and adjusting the pH to 8.0–10.0.

[0013] In one embodiment, the method for flushing and cleaning the pre-filming of the blast furnace water system further includes: using a backflushing bypass as a blast furnace bypass, and hanging carbon steel, stainless steel, or copper plates on the backflushing bypass to monitor the pre-filming effect of S3.

[0014] Compared with the prior art, the advantages of the blast furnace water system flushing, cleaning and pre-filming method of the present invention are as follows:

[0015] 1. Conventional water supply from the bottom of the blast furnace upwards, while beneficial for boiler heating, easily leads to scale buildup. This invention, by setting up a backflushing bypass, flushes from the top of the blast furnace downwards, flushing away scale and other contaminants from the blast furnace pipelines, thoroughly cleaning the blast furnace water pipes and preventing blockages. The backflushing bypass facilitates convenient flushing of the blast furnace pipelines, enabling regular cleaning during production. Furthermore, the cleaning process involves first adding penetrant OG-702, degreaser OG-603, and defoamer to the water system, followed by stripping agent OG-501, cleaning corrosion inhibitor OG-206, complexing cleaner OG-602, organic cleaner OG-601, and defoamer. This method provides better decontamination and rust removal, ensuring long-term cleanliness and rust prevention of the water system pipelines.

[0016] 2. During backflushing, the first and second shut-off devices are closed, and the drain valve is opened. Water and impurities flowing out of the blast furnace pipeline are discharged through the drain valve. The backflushing bypass is equipped with a backflushing valve, which is closed to shut off the backflushing pipeline when the blast furnace is operating normally. The backflushing bypass does not affect the normal operation of the blast furnace, and its opening and closing are flexible, facilitating backflushing and cleaning, and aiding in routine blast furnace descaling and maintenance.

[0017] 3. A backflushing bypass can be used as a blast furnace bypass. Carbon steel, stainless steel, or copper plates can be hung on the backflushing bypass to monitor the pre-filming effect, making it convenient to carry out pre-filming operations on-site and intuitively.

[0018] 4. After pre-membrane preparation, replace with demineralized water, gradually replacing at a demineralized water supply capacity of approximately 50 m³ / h until the system water hardness is ≤15 mg / L and turbidity is ≤5 NTU. During the replacement process, add a protective membrane agent and adjust the pH to 8.0–10.0 to protect the new membrane from damage.

[0019] The invention will become clearer from the following description, taken in conjunction with the accompanying drawings, which are used to explain embodiments of the invention. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the existing blast furnace water system;

[0022] Figure 2 This is a schematic diagram of the flushing bypass structure according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the blast furnace water system according to an embodiment of the present invention.

[0024] Among them, 1. Blast furnace, 11. Cooling wall, 12. Water-cooled pipe, 2. Water station, 21. Main pump, 22. High-pressure pump, 23. Medium-pressure pump, 24. Dosing device, 3. Backflush bypass, 31. First cut-off device, 32. Second cut-off device, 33. Sewage valve, 34. Backflush valve, 35. Return valve, 36. Filter device, 41. Main inlet pipe, 42. Main return pipe, 43. Return ring pipe, 44. Pump booster pipe, 51. Tuyere sleeve, 52. Tuyere middle sleeve, 53. Deoxidizer, 54. Expansion tank, 55. Air cooler. Detailed Implementation

[0025] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0026] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] This implementation example Figure 2 , 3The blast furnace water system is equipped with a backflushing bypass 3. The inlet of the backflushing bypass 3 is connected to the outlet of the main power supply pump 21, and the outlet of the backflushing bypass 3 is connected to the return water main pipe 42. A first shut-off device 31 and a blowdown valve 33 are installed between the inlet of the backflushing bypass 3 and the bottom inlet of blast furnace 1. The first shut-off device 31 is located between the blowdown valve 33 and the inlet of the backflushing bypass 3. A second shut-off device 32 is installed between the outlet of the backflushing bypass 3 and the inlet of the water station 2. The outlet of the blowdown valve 33 is connected to the return water main pipe 42. A return valve 35 and a filter device 36 are installed between the blowdown valve 33 and the return water main pipe 42. The blast furnace 1 piping includes parallel cooling walls 11, water-cooled pipes 12, and serpentine pipes, etc. The backflushing bypass 3 is equipped with a backflushing valve 34. When blast furnace 1 is operating normally, the backflushing valve 34 is closed to shut off the backflushing pipeline. A dosing device 24 is installed upstream of the main power supply pump 21, through which corresponding chemicals can be added to the water system. In this embodiment, the first cutting-off device 31 and the second stage device are blind plates.

[0029] The present invention provides a method for flushing, cleaning, and pre-filming a blast furnace water system, comprising the following steps:

[0030] S0: Before S1, close the first shut-off device 31 and the second shut-off device 32, open the drain valve 33, and close the return valve 35 to shut off the pipeline from the outlet of the drain valve 33 to the return water main 42. Use water from the water station 2 to backwash the pipeline inside the blast furnace 1, and discharge the wastewater flowing from the bottom of the pipeline of the blast furnace 1 through the drain valve 33;

[0031] S1: Close the first shut-off device 31 and the second shut-off device 32, open the drain valve 33, open the pipeline from the outlet of the drain valve 33 to the return water main pipe 42, and close the other outlet of the drain valve 33 with a blind flange. Water and impurities flowing out from the bottom of the blast furnace 1 pipeline flow back to the return water main pipe 42 through the drain valve 33 for circulation cleaning. Add penetrant OG-702, degreasing agent OG-603, and defoamer to the water system. These agents are amphoteric, change the interface between water and oil, and penetrate into the oil stains on the metal wall, causing them to gradually emulsify and dissolve in the water and be discharged with the water. The conveyed water flows through the backflushing bypass 3 from the top of the blast furnace 1 pipeline downwards into the blast furnace 1 pipeline to backflush and flush the blast furnace 1 pipeline. Circulate and flush for 3-5 hours, monitor the turbidity, and plot the turbidity curve. Turbidity monitoring is performed every two hours. Stop flushing when the turbidity curve shows an inflection point.

[0032] After S1 and before S2, drain the water from the blast furnace 1 pipeline and refill it with water;

[0033] S2: After S1, add stripping agent OG-501, cleaning corrosion inhibitor OG-206, complexing cleaning agent OG-602, organic cleaning agent OG-601, and defoamer to the water system. These components dissolve in the water through penetration, stripping, complexation, and loose dispersion, removing oxidized floating rust and scale generated during long-term operation. Water flows through backflushing bypass 3 from the top of blast furnace 1 pipeline downwards into blast furnace 1 pipeline for backflushing and rinsing. The process is repeated for 15–24 hours, monitoring iron ion levels and plotting an iron ion curve. In S2, pH is monitored hourly, and iron ion levels are monitored every two hours. Cleaning is stopped when the iron ion curve reaches an inflection point. During the cleaning process, the pH is controlled between 5.0 and 6.0.

[0034] S3: Following S2, pre-filming treatment is performed by adding pre-filming agent OG-308A, pre-filming aid OG-308B, and copper corrosion inhibitor OG-205 to the water system. This rapidly forms a dense and uniform protective film on the metal surface, isolating the water from the equipment and preventing corrosion. Pre-filming is circulated for 48–60 hours. pH and reagent concentration are controlled; pH is measured every 2 hours, and reagent concentration every 4 hours. During the pre-filming circulation, a reverse pump is used for circulation. In S3, the water flow direction for pre-filming is the same as that for backwashing. Backwashing of impurities can continue to further enhance the rinsing effect. Water flowing from drain valve 33 passes through filter device 36 and returns to water station 2 via return water main pipe 42, further strengthening the decontamination effect. However, it is not limited to this embodiment. Alternatively, the drain valve 33 can be closed and the first cut-off device 31 and the second cut-off device 32 can be opened to perform pre-filming in a forward cycle, or forward pre-filming and reverse pre-filming can be performed alternately. During and after the pre-filming process, empty pipes in the system should be avoided.

[0035] S4: After S3, replace with demineralized water. Gradually replace with demineralized water at a supply capacity of about 50 m³ / h until the system water hardness is ≤15 mg / L and turbidity is ≤5 NTU. During the replacement process, add a protective film agent and adjust the pH to 8.0-10.0 to protect the new membrane from damage.

[0036] In either S1 or S2, the pump intervals in the water system are switched and cleaned.

[0037] In step S1, a portion of the water is replaced based on the turbidity of the flushing water. This replacement refers to releasing some water through drain valve 33 and then replenishing the water system.

[0038] In this invention, the backflushing bypass 3 can be used as a bypass for the blast furnace 1. When performing S3 pre-filming, the drain valve 33 is closed, and the first shut-off device 31 and the second shut-off device 32 are opened. The main pump 21 delivers water from the water station 2, partly through the pipeline of the blast furnace 1 from bottom to top, and partly through the backflushing bypass back to the return water main pipe 42 (in the opposite direction to the flow of the square flushing). Carbon steel, stainless steel or copper plates are hung on the backflushing bypass 3 to monitor the pre-filming effect of S3.

[0039] Normally, water is supplied to blast furnace 1 from the bottom upwards. While this method is beneficial for boiler heating, it can easily lead to scale buildup. This invention addresses this by setting up a backflushing bypass 3 to flush blast furnace 1 from top to bottom, which can wash away scale and other dirt from the pipelines of blast furnace 1, thoroughly flushing the water pipes of blast furnace 1 and preventing blockages.

[0040] The present invention has been described above in conjunction with the preferred embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations made in accordance with the essence of the present invention.

Claims

1. A method of flushing a pre-film in a blast furnace water system, characterized by, The blast furnace water system is provided with a backflush bypass, an inlet of the backflush bypass is communicated with an outlet of a main supply pump, and an outlet of the backflush bypass is communicated with a return water main; S1: adding a penetrating agent OG-702, an oil removal agent OG-603, and a defoaming agent into the water system, and conveying water to flow through the backflush bypass to input into the blast furnace pipeline from the top of the blast furnace pipeline downward, to backflush and clean the blast furnace pipeline, and to monitor turbidity and draw a turbidity curve, and to stop cleaning when an inflection point appears on the turbidity curve; S2: after S1, adding a stripping agent OG-501, a cleaning corrosion inhibitor OG-206, a complex cleaning agent OG-602, an organic cleaning agent OG-601, and a defoaming agent into the water system, and circulating cleaning for 15-24 hours, and conveying water to flow through the backflush bypass to input into the blast furnace pipeline from the top of the blast furnace pipeline downward, to backflush and clean the blast furnace pipeline, and to monitor an iron ion index and draw an iron ion curve, and to stop cleaning when an inflection point appears on the iron ion curve; S3: after backflush cleaning, performing pre-membrane treatment by adding a pre-membrane agent OG-308A and a pre-membrane aid OG-308B, and a copper corrosion inhibitor OG-205 into the water system, and circulating pre-membrane for 48-60 hours; In S3, the water flow direction is the same as that in backflush cleaning. A first shutoff device and a blowdown valve are arranged between the backflush bypass inlet and the blast furnace bottom inlet, the first shutoff device is arranged between the blowdown valve and the backflush bypass inlet, and a second shutoff device is arranged between the backflush bypass outlet and the water station inlet; 2. A method of pre-filming a blast furnace water system flush according to claim 1, wherein, Before S1, performing S0: opening the blowdown valve, and backflushing the pipeline in the blast furnace with water from the water station, and discharging waste water from the bottom of the blast furnace pipeline through the blowdown valve. The outlet of the blowdown valve is communicated with the return water main, and when performing S1 and S2, water from the blast furnace pipeline flows into the return water main through the blowdown valve to perform circulating cleaning.

3. A method of pre-filming a blast furnace water system flush according to claim 2, wherein, In S1 or S2, the pump interval in the water system is cleaned by switching pumps.

4. The method of claim 1, wherein the method further comprises, In S1, part of the water is replaced according to the turbidity of the water after cleaning.

5. The method of claim 1, wherein the method further comprises, After S1 and before S2, the water in the blast furnace pipeline is emptied and then filled with water again.

6. The method of claim 1, wherein the method further comprises, After S3, performing S4: replacing with desalted water, gradually replacing the water in the system to a water hardness of ≤15 mg / L and a turbidity of ≤5 NTU at a desalted water supply capacity of about 50 m^3 / h, and adding a membrane protection agent during the replacement process, and adjusting the pH to 8.0-10.

0.

7. The method of claim 1, wherein the method further comprises, The backflush bypass is used as a blast furnace bypass, and a carbon steel or stainless steel or copper coupon is hung on the backflush bypass to monitor the pre-membrane effect of S3.

8. A method of pre-filming a blast furnace water system flush according to claim 7, wherein, ​

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