Pickling treatment system and method of use thereof

Abstract

The present application relates to a pickling treatment system, comprising at least three pickling treatment units arranged in series, each pickling treatment unit being respectively provided with a circulating acid tank, each circulating acid tank being connected in series through a ladder flow pipe, the last circulating acid tank being provided with a new acid pipe, and the rest of the circulating acid tanks being at least partially offline acid tanks, the offline acid tank being provided with an override pipe, both ends of the override pipe being connected to the ladder flow pipe segments on the inlet and outlet sides of the offline acid tank, respectively, and control valves being respectively arranged on the override pipe and the ladder flow pipe segments on the inlet and outlet sides. The present application also relates to a method for using the pickling treatment system. In the present application, the circulating acid tanks are connected in series through a ladder flow pipe, and a plurality of offline acid tanks are arranged, so that the number and combination of pickling treatment units put into pickling work can be flexibly controlled, thereby meeting the pickling requirements of different production conditions, without the need to set up multiple production lines or stop production to prepare pickling liquid again, and the equipment investment and production cost can be significantly reduced.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical production technology, specifically relating to an acid pickling system and a method of using the acid pickling system. Background Technology

[0002] In the process of pickling non-oriented high-grade silicon steel sheets and strips using hydrochloric acid as pickling solution, there are many grades of non-oriented high-grade silicon steel products, and the requirements for pickling time and pickling solution concentration are different for different grades of silicon steel raw materials. This leads to the need to equip different production lines, which greatly increases the equipment investment cost and floor space. Alternatively, when switching steel grades, it is necessary to stop the machine to prepare pickling solution again, resulting in high production costs and low production efficiency. Summary of the Invention

[0003] This invention relates to a pickling system and a method of using the pickling system, which can at least solve some of the defects of the prior art.

[0004] This invention relates to a pickling system, comprising at least three pickling units arranged in series, each pickling unit being equipped with a circulating acid tank, and the circulating acid tanks being connected in series via a flow ladder.

[0005] The circulating acid tank of the primary pickling unit is equipped with an acid discharge pipe.

[0006] The circulating acid tank in the final pickling unit is equipped with a new acid pipe.

[0007] At least some of the remaining circulating acid tanks are offline acid tanks. The offline acid tanks are equipped with bypass pipes and offline control valve groups. The two ends of the bypass pipes are respectively connected to the cascade pipe sections on the inlet and outlet sides of the offline acid tanks. The offline control valve group includes a first control valve provided on the bypass pipe and two second control valves respectively provided on the cascade pipe sections on the inlet and outlet sides. The second control valves are located between the offline acid tanks and the bypass pipe connection points on the corresponding sides.

[0008] The circulating acid tank is connected to the corresponding pickling unit through an acid supply pipe and a return pipe, and a heater is provided on the acid supply pipe.

[0009] The circulating acid tank is also equipped with a bypass pipe, which is connected in parallel to the acid supply pipe section on the outlet side of the heater.

[0010] Downstream of the final pickling unit are a cleaning unit and a strip surface drying unit connected in series.

[0011] The cleaning unit adopts a multi-stage countercurrent cascade cleaning unit.

[0012] The present invention has at least the following beneficial effects:

[0013] In this invention, each circulating acid tank is connected in series and several offline acid tanks are set up, which can flexibly control the number and combination of acid pickling units put into acid pickling work, thereby meeting the acid pickling requirements of different production conditions. For example, it can meet the different requirements of acid pickling time / acid concentration for the production of different high-grade silicon steels. There is no need to set up multiple production lines or stop the machine to re-prepare the acid pickling solution, which can significantly reduce equipment investment and production costs. Attached Figure Description

[0014] 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.

[0015] Figure 1 This is a schematic diagram of the pickling system provided in an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the structure of the acid pickling tank with inducible hydrogen control provided in an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the inducer provided in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1

[0020] like Figure 1 This invention provides a pickling system comprising at least three pickling units 1 arranged in series, each pickling unit 1 being equipped with a circulating acid tank 2, and the circulating acid tanks 2 being connected in series via a flow ladder pipe 42.

[0021] The circulating acid tank 2 of the primary pickling treatment unit 1 is equipped with an acid discharge pipe 43.

[0022] The circulating acid tank 2 of the final pickling unit 1 is equipped with a new acid pipe 41.

[0023] The remaining circulating acid tank 2 is at least partially an offline acid tank. The offline acid tank is equipped with a bypass pipe 21 and an offline control valve assembly. The two ends of the bypass pipe 21 are respectively connected to the stepped flow pipe 42 section on the inlet and outlet sides of the offline acid tank. The offline control valve assembly includes a first control valve 211 provided on the bypass pipe 21 and two second control valves 22 respectively provided on the stepped flow pipe 42 section on the inlet and outlet sides. The second control valves 22 are located between the offline acid tank and the bypass point of the corresponding side bypass pipe 21.

[0024] The aforementioned pickling unit 1 can adopt a tank-type structure, i.e., constitute a pickling tank. In one embodiment, the pickling tank includes a tank body and a tank cover. The tank body is preferably a long and narrow steel structure tank body, and the tank cover preferably includes multiple top cover segments, which are arranged sequentially along the length of the tank body. The top cover segments can be automatically opened and closed by an opening and closing drive device, which includes, but is not limited to, a hydraulic drive method. In one embodiment, the inner surface of the tank body uses corrosion-resistant vulcanized rubber as the first lining, and the second lining uses acid-resistant stone lining. The first lining is attached to the outer surface of the second lining. Preferably, the bottom of the tank body is V-shaped, and an exhaust port can be set at the lowest point. Wear-resistant strip-shaped stone for supporting the strip is preferably set at certain intervals on the V-shaped slope. Preferably, a side spray unit is set on the tank wall for spraying acid into the tank.

[0025] The circulating acid tank 2 is connected to the pickling unit 1 via an acid supply pipe 31 and a return pipe 32. Further, a bypass pipe 36 can be connected to the acid supply pipe 31, which is connected to the circulating acid tank 2. Both the bypass pipe 36 and the acid supply pipe 31 are equipped with control valves, wherein the control valve on the acid supply pipe 31 is preferably located downstream of the bypass point of the bypass pipe 36. Additionally, the vent pipe 33 provided on the pickling unit 1 can also be connected to the circulating acid tank 2, and a vent valve is provided on the vent pipe 33.

[0026] Among them, such as Figure 1 Preferably, a heater 34 is provided on the acid supply pipe 31; when a bypass pipe 36 is connected to the acid supply pipe 31, the bypass point of the bypass pipe 36 is preferably located on the outlet side of the heater 34.

[0027] In one embodiment, a cleaning unit and a strip surface drying unit are connected in series downstream of the final pickling unit 1, which can perform surface cleaning and drying on the pickled strip. The cleaning unit is preferably a multi-stage countercurrent cascade cleaning unit, and the strip surface drying unit includes, but is not limited to, a hot air drying device.

[0028] Except for the first and last circulating acid tanks 2, it is preferable that the other circulating acid tanks 2 are all offline acid tanks.

[0029] From the final pickling unit 1 towards the first pickling unit 1, the acid concentration decreases sequentially.

[0030] In one embodiment, the pickling system described above uses hydrochloric acid as the acid solution.

[0031] Example 2

[0032] This invention provides a method for using the above-described pickling system, including:

[0033] Based on the pickling conditions, select an offline pickling tank to be used in the pickling operation to meet the corresponding pickling requirements.

[0034] The number of offline acid tanks used for pickling can be zero, or all offline acid tanks can be used for pickling, meaning all offline acid tanks are offline, or at least some offline acid tanks are online. Since the acid concentrations in each circulating acid tank 2 are different, different pickling effects can be achieved by selecting the location of the offline acid tanks, that is, controlling the combination of circulating acid tanks 2 used for pickling.

[0035] For the circulating acid tank 2 that needs to be taken offline, open the first control valve 211 on its corresponding overpass pipe 21 and close the corresponding second control valve 22.

[0036] For the offline circulating acid tank 2, its corresponding pickling unit 1 is also offline, that is, temporarily isolated from strip production; when the pickling unit 1 is offline, the acid can be drained, or the liquid level in the acid can be lowered, or the acid in the acid can be made non-flowing, depending on the sensitivity of the strip to the acid.

[0037] In one embodiment, for the offline circulating acid tank 2, the acid solution in the tank is still pumped to the heater 34 through the acid supply pump 35 on its acid supply pipe 31. The heated acid solution flows back to the circulating acid tank 2 through the bypass pipe 36. This ensures that the temperature of the acid solution in the tank can be maintained, so that it can be put into production immediately when it is online later. In addition, for the previous circulating acid tank 2 of the offline circulating acid tank 2 (for example, when the third circulating acid tank 2 is offline, the previous circulating acid tank is the second circulating acid tank 2), according to the sensitivity of the strip to the acid concentration, acid or water can be added to the previous circulating acid tank 2 to control the acid concentration in the previous circulating acid tank 2.

[0038] by Figure 1 The pickling system shown is an example, including the following operating conditions:

[0039] (1) All pickling units 1 from NO.1 to NO.4 are put into pickling operation. The first control valve 211 on each bypass pipe 21 is closed and the second control valve 22 is opened. At this time, fresh acid is supplied to NO.4 circulating acid tank 2 and flows through NO.3 circulating acid tank 2, NO.2 circulating acid tank 2 and NO.1 circulating acid tank 2 in sequence.

[0040] (2) Close the second control valve 22 configured in NO.2 circulating acid tank 2, and open the first control valve 211 on the bypass pipe 21 configured in NO.2 circulating acid tank 2; close all the first control valves 211 on the other bypass pipes 21, and open all the second control valves 22 configured in NO.3 circulating acid tank 2, so that NO.2 pickling unit 1 can be temporarily isolated from strip production, and NO.1 circulating acid tank 2, NO.3 circulating acid tank 2 and NO.4 pickling unit 1 can all be put into pickling operation. The acid supply pump 35 configured in NO.2 circulating acid tank 2 can be turned on or off.

[0041] (3) Close the second control valve 22 configured in NO.3 circulating acid tank 2, and open the first control valve 211 on the bypass pipe 21 configured in NO.3 circulating acid tank 2; close all the first control valves 211 on the other bypass pipes 21, and open all the second control valves 22 configured in NO.2 circulating acid tank 2, so that NO.3 pickling unit 1 can be temporarily isolated from strip production, and NO.1 circulating acid tank 2, NO.2 circulating acid tank 2 and NO.4 pickling unit 1 can all be put into pickling work. The acid supply pump 35 configured in NO.3 circulating acid tank 2 can be turned on or off.

[0042] (4) Close the second control valve 22 configured in NO.2 circulating acid tank 2 and NO.3 circulating acid tank 2, and open the first control valve 211 on the bypass pipe 21 configured in NO.2 circulating acid tank 2 and NO.3 circulating acid tank 2; this allows NO.2 pickling unit 1 and NO.3 pickling unit 1 to be temporarily isolated from strip production, while NO.1 circulating acid tank 2 and NO.4 pickling unit 1 are put into pickling operation. The acid supply pump 35 configured in NO.2 circulating acid tank 2 and NO.3 circulating acid tank 2 can be turned on or off.

[0043] (5) If production needs to be stopped urgently, taking the sudden stop of operation 1 as an example, the vent valves on each vent pipe 33 will be automatically opened to quickly vent each pickling unit 1 and prevent the strip material stopped in the pickling unit 1 from being over-corroded. The control valves on the bypass pipes 36 configured on each circulating acid tank 2 will be automatically opened and the control valves on the acid supply pipes 31 will be closed. The acid in the circulating acid tank 2 will be pumped to the heater 34 through each acid supply pump 35 and the heated acid will flow back to the circulating acid tank 2 through the bypass pipes 36.

[0044] Example 3

[0045] This embodiment further optimizes the above-described Embodiment 1 / Embodiment 2.

[0046] In each pickling unit 1, at least some pickling units 1 adopt pickling tanks 1 with induced hydrogen control.

[0047] like Figure 2 and Figure 3 For the pickling tank 1 with induced hydrogen control, the pickling tank 1 is equipped with at least one inducer 6. The inducer 6 has an air inlet, an air supply outlet and an air return outlet. The air inlet is connected to a gas supply pipe 61. The air supply outlet and the air return outlet are both connected to the tank cavity of the pickling tank 1. At least some of the air return outlets of the inducers 6 are set to correspond to the hydrogen enrichment zone of the pickling tank 1.

[0048] Preferably, the inducer 6 is arranged at the top of the pickling tank 1.

[0049] The inducers 6 are preferably arranged in multiples, which can improve the control effect and efficiency of hydrogen concentration in the tank. Preferably, at least some of the inducers 6 are arranged in the hydrogen enrichment area of ​​the pickling tank 1, for example, by opening at the top of the hydrogen enrichment area and connecting to the return air inlet of the inducer 6, or by connecting through a return air pipe.

[0050] Preferably, the pickling tank 1 is provided with an exhaust vent, which is connected to an acid mist extraction mechanism 7. Optionally, the exhaust vent is located on the side of the pickling tank 1. In one embodiment, such as Figure 2 The acid mist extraction mechanism 7 mentioned above includes an acid mist collection pipe, a scrubbing tower 71 and a centrifugal fan arranged on the acid mist collection pipe. The mist is removed by the spray mechanism in the scrubbing tower 71, and acid liquid can be recovered at the same time.

[0051] In this embodiment, by setting an inducer 6, the gas in the pickling tank 1 is extracted and then sent back into the tank. On the one hand, this can change the gas distribution in the tank, improve the gas flow in the tank, and prevent hydrogen enrichment. On the other hand, it can also dilute the atmosphere in the tank, thereby reducing the possibility of hydrogen combustion and explosion in the tank and effectively improving production safety.

[0052] In one embodiment, the gas supply pipe 61 supplies an inert gas to dilute the atmosphere in the tank while preventing hydrogen explosion. The inert gas includes, but is not limited to, nitrogen.

[0053] In one embodiment, the air jet output from the air outlet takes at least one of the following forms:

[0054] (1) The air jet is directed toward the hydrogen enrichment area to drive the hydrogen in the tank to the exhaust port of pickling tank 1, which can increase the flow of hydrogen and make it easier for hydrogen to be discharged from the tank.

[0055] (2) The air jet is directed toward the area around the hydrogen enrichment zone to create a negative pressure suction effect on the hydrogen enrichment zone. The negative pressure effect generated by the jet can draw hydrogen from the hydrogen enrichment zone and increase the fluidity of hydrogen.

[0056] As can be seen, in this embodiment, the air supply power of the inducer 6 can further control hydrogen, and at the same time save the exhaust energy consumption of the pickling tank 1.

[0057] Preferably, the air supply outlet and the exhaust outlet should be staggered to avoid airflow short-circuiting. The air supply jet is preferably staggered with the return air outlet.

[0058] In one embodiment, such as Figure 3 A first adsorbent layer 64 is provided in the return air channel 62 of the inducer 6. Preferably, the first adsorbent layer 64 is mainly used to absorb acid mist in the return air. For example, the first adsorbent layer 64 is made of SDG adsorbent or activated carbon adsorbent.

[0059] Among them, the return air inlet / return air channel 62 in the inducer 6 can be multiple, which can increase the processing capacity.

[0060] In one embodiment, such as Figure 3 A second adsorbent layer 65 is also provided in the return air channel 62 of the inducer 6. The second adsorbent layer 65 is located downstream of the first adsorbent layer 64, that is, the second adsorbent layer 65 is located on the side of the first adsorbent layer 64 away from the return air inlet. The return air is processed sequentially through the first adsorbent layer 64 and the second adsorbent layer 65.

[0061] In one embodiment, the second adsorbent layer 65 uses an adsorbent capable of adsorbing hydrogen, including but not limited to activated carbon with a high specific surface area or carbon nanotubes.

[0062] Based on the above scheme, hydrogen adsorption can be achieved in the inducer 6. The hydrogen concentration in the air jet is low, which can effectively reduce the hydrogen concentration in the tank and achieve significant hydrogen control. The return air first passes through the first adsorbent layer 64 to adsorb acid mist, and then enters the second adsorbent layer 65 for hydrogen adsorption treatment. The process is highly reasonable, which can ensure the hydrogen adsorption effect and reduce the load on the second adsorbent layer 65.

[0063] In one embodiment, such as Figure 3 A third adsorbent layer 66 is provided in the air supply channel 63 of the inducer 6. Preferably, the third adsorbent layer 66 is an adsorbent capable of adsorbing hydrogen, including but not limited to high specific surface area activated carbon or carbon nanotubes. Hydrogen adsorption can also be achieved through this third adsorbent layer 66. In particular, when the inducer 6 is simultaneously provided with a second adsorbent layer 65 and a third adsorbent layer 66, the hydrogen adsorption effect can be further improved.

[0064] In one embodiment, such as Figure 3 The aforementioned inducer 6 includes a static pressure box 67 and an induction box 68. The aforementioned air supply pipe 61 is connected to the static pressure box 67. The outlet side of the static pressure box 67 is provided with an air inlet nozzle, which faces into the induction box 68, for introducing an air jet into the induction box 68 to form a negative pressure. Both the return air port and the supply air port are provided on the induction box 68; the outlet side of the induction box 68 is provided with an air supply nozzle, which faces into the pickling tank 1, for introducing a supply air jet into the pickling tank 1.

[0065] Preferably, the spray angle of the air supply nozzle is adjustable, which can improve process flexibility.

[0066] In one embodiment, such as Figure 2 The pickling tank 1 is equipped with a hydrogen concentration detection unit 8 for detecting the hydrogen concentration in the tank. An induction control valve 611 is provided on the gas supply pipeline 61, and the hydrogen concentration detection unit 8 is preferably interlocked with the induction control valve 611 to facilitate automatic hydrogen control.

[0067] When used, it specifically includes:

[0068] The hydrogen concentration in the pickling tank 1 is detected. When the hydrogen concentration in the tank reaches a set threshold, the inducer 6 is activated to reduce the hydrogen concentration in the tank.

[0069] In one embodiment, when the hydrogen concentration in the tank reaches a first set threshold, the inducer 6 is activated to perform preliminary hydrogen control.

[0070] When the hydrogen concentration in the tank reaches the second set threshold, acid mist is extracted through the exhaust port, which can quickly reduce the hydrogen concentration in the tank. During this process, the inducer 6 can work synchronously.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pickling system, characterized in that, The system includes at least three pickling units arranged in series, each pickling unit being equipped with a circulating acid tank, and the circulating acid tanks being connected in series via a flow ladder. The circulating acid tank of the primary pickling unit is equipped with an acid discharge pipe. The circulating acid tank in the final pickling unit is equipped with a new acid pipe. At least some of the remaining circulating acid tanks are offline acid tanks. The offline acid tanks are equipped with bypass pipes and offline control valve groups. The two ends of the bypass pipes are respectively connected to the cascade pipe sections on the inlet and outlet sides of the offline acid tanks. The offline control valve group includes a first control valve provided on the bypass pipe and two second control valves respectively provided on the cascade pipe sections on the inlet and outlet sides. The second control valves are located between the offline acid tanks and the bypass pipe connection points on the corresponding sides. In each pickling unit, at least some pickling units adopt pickling tanks with inducible hydrogen control. The pickling tank is equipped with at least one inducer. The inducer has an air inlet, an air supply outlet and an air return outlet. The air inlet is connected to a gas supply pipe. The air supply outlet and the air return outlet are both connected to the tank cavity of the pickling tank. The air return outlet of at least some inducers is set to correspond to the hydrogen enrichment zone of the pickling tank. The air jet output from the air outlet is directed toward the hydrogen enrichment area to drive the hydrogen in the tank to the exhaust port of the pickling tank; and / or, the air jet output from the air outlet is directed toward the surrounding area of ​​the hydrogen enrichment area to create a negative pressure suction effect on the hydrogen enrichment area. The gas supply pipeline supplies inert gas; The pickling tank is equipped with an exhaust vent, which is connected to an acid mist extraction mechanism. The acid mist extraction mechanism includes an acid mist collection pipe and a washing tower and a centrifugal fan arranged on the acid mist collection pipe. The exhaust vent is located on the side of the pickling tank, and the air supply vent and the exhaust vent are staggered to avoid airflow short circuit.

2. The pickling system as described in claim 1, characterized in that: The circulating acid tank is connected to the corresponding pickling unit through an acid supply pipe and a return pipe, and a heater is provided on the acid supply pipe.

3. The pickling system as described in claim 2, characterized in that: The circulating acid tank is also equipped with a bypass pipe, which is connected in parallel to the acid supply pipe section on the outlet side of the heater.

4. The pickling system as described in claim 1, characterized in that: Downstream of the final pickling unit are a cleaning unit and a strip surface drying unit connected in series.

5. The pickling system as described in claim 4, characterized in that: The cleaning unit adopts a multi-stage countercurrent cascade cleaning unit.

6. The method of using the pickling system as described in any one of claims 1 to 5, characterized in that, The method of use includes: Based on the pickling conditions, select an offline pickling tank to be put into pickling operation to meet the corresponding pickling requirements; for the circulating pickling tank to be offline, open the first control valve on its overpass pipe and close the corresponding second control valve.

7. The method of use as described in claim 6, characterized in that, For offline circulating acid tanks, the acid in the tank is still pumped to the heater through the acid supply pump on its acid supply pipe. The heated acid is then returned to the circulating acid tank through the bypass pipe to ensure the temperature of the acid in the tank.

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