Treatment device for flushing water in stainless steel pickling process

Abstract

The utility model discloses a treatment device for washing water in a stainless steel pickling process, which comprises a pretreatment unit, a first-stage membrane unit, a second-stage membrane unit and a third-stage membrane unit, the pretreatment unit is used for precipitating solid impurities in the washing water, the first-stage membrane unit is used for filtering suspended particles in the washing water, the second-stage membrane unit comprises a first circulating tank and a first membrane system, and the third-stage membrane system comprises a second circulating tank and a third circulating tank. The first-stage membrane unit comprises a first circulating tank and a first membrane system, the first circulating tank is communicated with the first-stage membrane tank, the first membrane system is communicated with the first circulating tank, the first membrane system is used for discharging regenerated reuse water, the third-stage membrane unit comprises a second circulating tank and a second membrane system, the second circulating tank is communicated with the first concentrated water discharge branch, the second membrane system is communicated with the second circulating tank, and the second membrane system is used for discharging regenerated acid. The first membrane system generates regenerated reuse water, and the second membrane system generates regenerated acid, so that the washing water does not need to be additionally subjected to chemical adding treatment, the problem of mud cake generation due to chemical adding is avoided, and the technical effect of water resource treatment of the washing water is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of stainless steel pickling, in particular to a treatment device for flushing water in the process of stainless steel pickling. Background Art

[0002] During the production and processing of stainless steel, especially in the surface treatment stage, such as electroplating and before spraying, a layer of black iron oxide is easily formed on the surface. Usually, it needs to be pickled to remove the oxides and impurities on the surface. In order to ensure the pickling and dephosphorization effect, mixed acid is usually used for continuous pickling, such as 8%-20% HNO3 and 1%-5% HF. After pickling, a large amount of water is needed to rinse the workpiece to remove the residual acid on the surface and the oxides, metal ions, etc. generated during the pickling process.

[0003] A large amount of flushing water is generated during the flushing process. The main component of the flushing water is the same as the waste acid, but the difference is that the concentration is relatively low. The flushing water still has a certain acidity and toxicity (containing toxic pollutants such as nickel, chromium, and fluorine).

[0004] Common methods for treating flushing water include neutralization precipitation, which requires adding chemicals to adjust the pH value of the flushing water. This process will produce heavy metal sludge, and the disposal cost of the sludge is high. Salt and NO3- exist in the water after neutralization, which requires further desalination treatment. The acid, water, Fe, Cr, Ni, Cu and other metals in the waste liquid cannot be utilized, resulting in great waste. Therefore, it is necessary to design a flushing water treatment device. Utility Model Content

[0005] The embodiment of the present application provides a treatment device for rinse water in a stainless steel pickling process, which is used to solve the problem that the existing rinse water needs to add chemicals, produces mud cakes, or produces waste liquid that is difficult to recycle.

[0006] The embodiment of the present application provides a device for treating flushing water in a stainless steel pickling process, comprising: a pretreatment unit, a primary membrane unit, a secondary membrane unit, and a tertiary membrane unit;

[0007] The pre-processing unit comprises:

[0008] Sedimentation tank, used to receive and settle solid impurities in the flushing water;

[0009] A first sewage discharge device, connected to the sedimentation tank, for discharging impurities;

[0010] The primary membrane unit comprises:

[0011] A primary membrane tank connected to the sedimentation tank and used to filter suspended particles in the flushing water;

[0012] A second sewage discharge device, connected to the primary membrane pool, for discharging impurities;

[0013] The secondary membrane unit comprises:

[0014] A first circulation tank is connected to the primary membrane pool;

[0015] A first membrane system is connected to the first circulation tank, and the first membrane system comprises: a first produced water discharge branch and a first concentrated water discharge branch, wherein the first produced water discharge branch is used to discharge the regenerated reuse water;

[0016] The three-stage membrane unit comprises:

[0017] a second circulation tank, connected to the first concentrated water discharge branch, and used for receiving concentrated water discharged from the first concentrated water discharge branch;

[0018] The second membrane system is communicated with the second circulation tank, and the second membrane system comprises: a second produced water discharge branch, and the second produced water discharge branch is used to discharge the regenerated acid.

[0019] The beneficial effects of the above embodiment are: regeneration reuse water is generated through the first membrane system, and metal ions in the flushing water are filtered through the second membrane system to produce regeneration acid. There is no need for additional treatment of the flushing water with chemicals, thus avoiding the problem of mud cake produced by adding chemicals, and achieving the technical effect of resource treatment of flushing water.

[0020] Based on the above embodiments, the embodiments of the present application may also be improved as follows:

[0021] In one embodiment of the present application: the first sewage discharge device includes: a first mud pump, the first mud pump connects the sedimentation tank with the filter press; the second sewage discharge device includes: a second mud pump, the second mud pump connects the primary membrane tank with the above-mentioned filter press, and the discharge port of the filter press is connected to the primary membrane tank. The beneficial effect of this step: the solid impurities are compressed by the filter press, and the filtrate is returned to the primary membrane unit, thereby improving the recovery rate of the waste liquid.

[0022] In one embodiment of the present application: the primary membrane unit further comprises: an aeration pipe, the aeration pipe is connected to the primary membrane pool, and the aeration pipe is used to aerate and flush the filter membrane in the primary membrane pool. The beneficial effect of this step: flushing the filter membrane through the aeration pipe prevents the filter membrane from being blocked.

[0023] In one embodiment of the present application: the secondary membrane unit further comprises: a first liquid level gauge, a first lifting pump, a first pressure sensor assembly, a first filter, and a first high-pressure pump, wherein the first liquid level gauge is installed in the first circulation tank, and the first circulation tank is connected to the first membrane system through the first lifting pump, the first filter, and the first high-pressure pump, and the first pressure sensor assembly is connected to the pipeline of the secondary membrane unit. The beneficial effects of this step are: the action of the first lifting pump is controlled by the first liquid level gauge, and whether the first filter and the first membrane system are blocked is determined by the first pressure sensor assembly, and low-pressure protection and high-pressure protection are performed on the first high-pressure pump at the same time.

[0024] In one embodiment of the present application: the three-stage membrane unit also includes: a second liquid level gauge, a second lifting pump, a second pressure sensor assembly, a second filter, and a second high-pressure pump. The second liquid level gauge is installed in the second circulation tank. The second circulation tank is connected to the second membrane system through the second lifting pump, the second filter, and the second high-pressure pump. The second pressure sensor assembly is connected to the pipeline of the three-stage membrane unit. The beneficial effects of this step are: the action of the second lifting pump is controlled by the second liquid level gauge, the second filter and the second membrane system are judged to be blocked by the second pressure sensor assembly, and the second high-pressure pump is protected by low pressure and high pressure.

[0025] In one embodiment of the present application: the secondary membrane unit further includes: a first concentrated water return branch, connecting the concentrated water outlet of the first membrane system with the first circulation tank, for returning the concentrated water to the first circulation tank; a first concentrated water quick discharge branch, connecting the concentrated water outlet of the first membrane system with the first circulation tank, for quickly discharging the concentrated water to the first circulation tank. The beneficial effects of this step: the recovery rate of flushing water is improved through the first concentrated water return branch, the system is quickly discharged through the first concentrated water quick discharge branch, the flow rate is increased by pressure relief, and the pollutants accumulated on the membrane surface are taken away, so as to achieve the purpose of flushing the membrane.

[0026] In one of the embodiments of the present application: the three-stage membrane unit also includes: a second brine return branch, connecting the brine outlet of the second membrane system with the second circulation tank, for returning the brine to the second circulation tank; a second brine quick discharge branch, connecting the brine outlet of the second membrane system with the second circulation tank, for quickly discharging the brine to the second circulation tank; a second brine external discharge branch, connecting the brine outlet of the second membrane system with the waste acid regeneration system, for discharging the brine to the waste acid regeneration system. Beneficial effects of this step: the recovery rate of flushing water is improved through the second brine return branch, the system is quickly depressurized through the second brine quick discharge branch, the flow rate is increased by pressure relief, the pollutants accumulated on the membrane surface are taken away, the purpose of flushing the membrane is achieved, and the brine is sent out for harmless treatment through the second brine external discharge branch. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0028] Figure 1 It is a schematic diagram of the structure of a treatment device for flushing water in the stainless steel pickling process;

[0029] Figure 2 It is a schematic diagram of the structure of the pre-processing unit;

[0030] Figure 3 It is a schematic diagram of the structure of the primary membrane unit;

[0031] Figure 4 It is a schematic diagram of the structure of the secondary membrane unit;

[0032] Figure 5 Schematic diagram of the three-stage membrane unit structure.

[0033] Among them, 1 pretreatment unit, 101 sedimentation tank, 102 first sewage discharge device, 103 water inlet electromagnetic flow meter;

[0034] 2 primary membrane unit, 201 primary membrane tank, 202 second sewage discharge device, 203 filter membrane, 204 aeration pipe, 205 membrane tank liquid level gauge;

[0035] 3 secondary membrane unit, 301 first circulation tank, 302 first membrane system, 303 first produced water discharge branch, 304 first concentrated water discharge branch, 305 first liquid level meter, 306 first lift pump, 307 first filter, 308 first high-pressure pump, 309 first pressure sensor a, 310 first pressure sensor b, 311 first pressure sensor c, 312 first pressure sensor d, 313 first concentrated water reflux branch, 314 first concentrated water quick discharge branch, 315 first stop valve, 316 first rotor flowmeter, 317 first produced water electromagnetic flowmeter, 318 first electric valve;

[0036] 4 tertiary membrane unit, 401 second circulation tank, 402 second membrane system, 403 second liquid level meter, 404 second lift pump, 405 second filter, 406 second high-pressure pump, 407 second concentrate reflux branch, 408 second concentrate quick discharge branch, 409 second concentrate external discharge branch, 410 second stop valve, 411 second concentrate electromagnetic flowmeter, 412 second rotor flowmeter, 413 second produced water electromagnetic flowmeter, 414 second electric valve. DETAILED DESCRIPTION

[0037] In this application, unless otherwise clearly specified and limited, the terms in this application should be understood in a broad sense, such as connection can be fixed connection, detachable connection or integration, direct connection or indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of different terms in this utility model can be understood according to specific circumstances, and the scope of the specific meaning should be limited to realizing the functions of this application.

[0038] Embodiment 1

[0039] like Figure 1-5 As shown, a device for treating flushing water in a stainless steel pickling process comprises: a pretreatment unit 1, a primary membrane unit 2, a secondary membrane unit 3, and a tertiary membrane unit 4. The pretreatment unit 1 comprises: a sedimentation tank 101, a first blowdown device 102, the sedimentation tank 101 is used to receive and precipitate solid impurities in the flushing water, the first blowdown device 102 is connected to the sedimentation tank 101, and is used to discharge impurities; the primary membrane unit 2 comprises: a primary membrane pool 201, a second blowdown device 202, the primary membrane pool 201 is connected to the sedimentation tank 101, and is used to filter suspended particles in the flushing water, the second blowdown device 202 is connected to the primary membrane pool 201, and is used to discharge impurities; the secondary membrane unit 3 comprises: a first circulation tank 301, a first membrane system 302, the first circulation tank 301 is connected to the primary membrane pool 201, and the second blowdown device 202 is connected to the primary membrane pool 201, and is used to discharge impurities. A membrane system 302 is connected to the first circulation tank 301, and the first membrane system 302 includes: a first water production discharge branch 303, a first concentrated water discharge branch 304, and the first water production discharge branch 303 is used to discharge regenerated reuse water; the tertiary membrane unit 4 includes: a second circulation tank 401, a second membrane system 402, the second circulation tank 401 is connected to the first concentrated water discharge branch 304, the second circulation tank 401 is used to receive concentrated water discharged from the first concentrated water discharge branch 304, and the second membrane system 402 is connected to the second circulation tank 401, and the second membrane system 402 includes: a second water production discharge branch, and the second water production discharge branch is used to discharge regenerated acid.

[0040] Specifically, the first membrane system 302 uses a desalinated membrane to produce regenerated reused water, which can be reused for producing flushing water; the second membrane system 402 uses a nanofiltration membrane, which is the concentrate of the first membrane system 302 and uses a nanofiltration membrane with a large pore size to produce regenerated acid. That is, the water in the flushing water is first extracted with a desalinated membrane, and the produced reused water basically does not contain metal ions but contains a small amount of acid. Then the concentrate is nanofiltered through the second module system 402. Nanofiltration does not intercept acid, but only intercepts metal ions, and the produced water is clean regenerated acid. Specifically, Figure 2 As shown, the sedimentation tank 101 is equipped with an inlet electromagnetic flowmeter 103, and the inlet electromagnetic flowmeter 103 is used to measure the total inlet water volume.

[0041] Specifically, the purpose of setting up a sedimentation tank is to remove the scale shed during the pickling process, generally called acid sludge, which is iron oxide and easily precipitates, from the flushing wastewater by sedimentation.

[0042] Specifically, Figure 2 , 3 As shown, the first sewage discharge device 102 includes: a first sludge pump and a filter press, the first sludge pump connects the sedimentation tank 101 with the filter press; the second sewage discharge device 202 includes: a second sludge pump, the second sludge pump connects the primary membrane tank 201 with the filter press, the discharge port of the filter press is connected with the primary membrane tank 201, the first sludge pump and the second sludge pump are used to regularly extract impurities from the bottom of the tank and transport them to the filter press for filtration, recover the filter residue, and return the filtrate to the primary membrane tank 201. The solid impurities are compressed by the filter press, and the filtrate is returned to the primary membrane unit 2, so as to improve the recovery rate of the waste liquid.

[0043] Specifically, Figure 2 As shown, a filter membrane 203 is disposed in the primary membrane pool 201. In this embodiment, the filter membrane 203 adopts an acid-resistant MBR membrane component, but is not limited to the acid-resistant MBR membrane component. Tubular microfiltration membranes, tubular ultrafiltration membranes, etc. can also be used. The MBR membrane component is connected to the primary membrane pool 201 through a UPVC bracket.

[0044] Specifically, Figure 3 As shown, the primary membrane unit 2 further includes: an aeration pipe 204, the aeration pipe 204 is connected to the primary membrane pool 201, one end of the aeration pipe 204 is communicated with the inner side of the MBR membrane assembly, the aeration pipe 204 is externally connected to an aeration device, and the aeration pipe 204 is used to aerate and flush the filter membrane 203 in the primary membrane pool 201. Compressed air is introduced into the aeration pipe 204 to form stirring, and at the same time, the surface of the MBR membrane assembly is flushed to prevent mud residue from accumulating on the membrane surface and clogging the membrane.

[0045] Specifically, Figure 3 As shown, the first-level membrane pool 201 is equipped with a membrane pool level meter 205 for measuring the liquid level in the first-level membrane pool 201. The water production end of the MBR membrane assembly is connected to a suction pump through a pipeline. A pressure sensor is installed on the inlet of the suction pump. The membrane pool level meter 205 controls the start and stop of the suction pump.

[0046] Specifically, Figure 4As shown, the secondary membrane unit 3 further includes: a first liquid level gauge 305, a first lifting pump 306, a first pressure sensor assembly, a first filter 307, and a first high-pressure pump 308. The first liquid level gauge 305 is installed in the first circulation tank 301. The first circulation tank 301 is connected to the first membrane system 302 through the first lifting pump 306, the first filter 307, and the first high-pressure pump 308. The first pressure sensor assembly is connected to the pipeline of the secondary membrane unit 3. The start and stop of the first lifting pump 306 is controlled by the first liquid level gauge 305. The first liquid level gauge 305 also controls the action of the suction pump together with the membrane pool liquid level gauge 205, that is, the suction pump can only be started when the set conditions of the first liquid level gauge 305 and the membrane pool liquid level gauge 205 are met. The first pressure sensor assembly is used to determine whether the first filter 307 and the first membrane system 302 are blocked, and the first high-pressure pump 308 is protected by low pressure and high pressure.

[0047] Specifically, Figure 4 As shown, the first pressure sensor assembly includes: a first pressure sensor a309, a first pressure sensor b310, a first pressure sensor c311, and a first pressure sensor d312. The first pressure sensor a309 is located at the liquid inlet of the first filter 307, the first pressure sensor b310 is located between the liquid outlet of the first filter 307 and the liquid inlet of the first high-pressure pump 308, the first pressure sensor c311 is located between the liquid outlet of the first high-pressure pump 308 and the liquid inlet of the first membrane system 302, and the first pressure sensor d312 is located at the liquid outlet of the first membrane system 302.

[0048] Specifically, Figure 4 As shown, the first high-pressure pump 308 adopts a high-pressure plunger pump. The first high-pressure pump 308 needs to meet the conditions of the first pressure sensor b310 and the first pressure sensor c311 when it is started; the first pressure sensor a309 and the first pressure sensor b310 monitor the changes in the inlet and outlet pressures of the first filter 307, and judge the fouling condition of the first filter 307 so as to replace the filter element in time; at the same time, the first pressure sensor b310 serves as a low-pressure protection for the first high-pressure pump 308, and the pressure of the first pressure sensor b310 needs to reach a certain range to allow the first high-pressure pump 308 to start; the first pressure sensor c311 and the first pressure sensor d312 monitor the inlet and outlet pressures of the first membrane system, and judge the fouling condition of the membrane so as to find problems in time and clean or replace it in time; at the same time, the first pressure sensor c311 serves as a high-pressure protection for the first high-pressure pump 308, and the first high-pressure pump 308 stops when the pressure of the first pressure sensor d312 is higher than the set range.

[0049] Specifically, Figure 5As shown, the three-stage membrane unit 4 also includes: a second liquid level gauge 403, a second lifting pump 404, a second pressure sensor assembly, a second filter 405, and a second high-pressure pump 406. The second liquid level gauge 403 is installed in the second circulation tank 401. The second circulation tank 401 is connected to the second membrane system 402 through the second lifting pump 404, the second filter 405, and the second high-pressure pump 406. The second pressure sensor assembly is connected to the pipeline of the three-stage membrane unit 4. The action of the second lifting pump 404 is controlled by the second liquid level gauge 403, and the second filter 405 and the second membrane system 402 are judged to be blocked by the second pressure sensor assembly, and the second high-pressure pump 406 is protected by low pressure and high pressure.

[0050] Specifically, Figure 5 As shown, the arrangement of the second pressure sensor assembly in the tertiary membrane unit 4 is the same as the arrangement of the first pressure sensor assembly in the secondary membrane unit 3, and the functions are also the same.

[0051] Specifically, Figure 4 As shown, the secondary membrane unit 3 further includes: a first concentrated water return branch 313 and a first concentrated water quick discharge branch 314. The first concentrated water return branch 313 connects the concentrated water outlet of the first membrane system 302 with the first circulation tank 301, and is used to return the concentrated water to the first circulation tank 301. The first concentrated water quick discharge branch 314 connects the concentrated water outlet of the first membrane system 302 with the first circulation tank 301, and is used to quickly discharge the concentrated water to the first circulation tank 301. The first concentrated water return branch 313 improves the recovery rate of the flushing water, and the first concentrated water quick discharge branch 314 realizes the quick discharge pressure relief of the system.

[0052] Specifically, Figure 4 As shown, the first concentrated water return branch 313 and the first concentrated water discharge branch 304 adjust the system pressure through the first stop valve 315 to control the operating pressure of the first membrane system 302. The first concentrated water return branch 313 and the first concentrated water quick discharge branch 314 are both equipped with a first rotor flowmeter 316. The first produced water discharge branch 303 is equipped with a first produced water electromagnetic flowmeter 317 for counting the produced water. The first concentrated water quick discharge branch 314 is controlled to start and stop through the first electric valve 318. The first electric valve 318 is opened and closed at a fixed time. When the first electric valve 318 is opened, the system quickly discharges the pressure. At the same time, the first high-pressure pump 308 is reduced in frequency to achieve the purpose of regularly flushing the membrane, prevent the accumulation of metal ions on the membrane surface to form fouling, and ensure the membrane water production.

[0053] Specifically, Figure 5As shown, the three-stage membrane unit 4 also includes: a second concentrate return branch 407, a second concentrate quick discharge branch 408, and a second concentrate external discharge branch 409. The second concentrate return branch 407 connects the concentrate outlet of the second membrane system 402 with the second circulation tank 401, and the second concentrate return branch 407 is used to return the concentrate to the second circulation tank 401. The second concentrate quick discharge branch 408 connects the concentrate outlet of the second membrane system 402 with the second circulation tank 401, and the second concentrate quick discharge branch 408 is used to quickly discharge the concentrate to the second circulation tank 401. The second concentrate external discharge branch 409 connects the concentrate outlet of the second membrane system 402 with the waste acid regeneration system (APU mixed acid regeneration system), and the second concentrate external discharge branch 409 is used to discharge the concentrate to the waste acid regeneration system. The second concentrate return branch 407 is used to improve the recovery rate of flushing water, and the second concentrate quick discharge branch 408 is used to achieve quick discharge pressure relief of the system. By increasing the flow rate through pressure relief, the pollutants accumulated on the membrane surface are taken away to achieve the purpose of flushing the membrane. The concentrate is sent out for harmless treatment through the second concentrate discharge branch 409.

[0054] Specifically, Figure 5 As shown, the second concentrated water return branch 407 and the second concentrated water discharge branch 409 adjust the system pressure through the second stop valve 410 to control the operating pressure of the second membrane system 402. The second concentrated water discharge branch 409 is also equipped with a second concentrated water electromagnetic flowmeter 411 for counting the amount of discharged concentrated water. The second concentrated water return branch 407 and the second concentrated water quick discharge branch 408 are both equipped with a second rotor flowmeter 412. The second produced water discharge branch is equipped with a second produced water electromagnetic flowmeter 413 for counting the amount of produced water. The second concentrated water quick discharge branch 408 is controlled to start and stop through the second electric valve 414. The second electric valve 414 is opened and closed at a fixed time. When the second electric valve 414 is opened, the system quickly discharges the pressure. At the same time, the second high-pressure pump 406 is reduced in frequency to achieve the purpose of regularly flushing the nanofiltration membrane, prevent the accumulation of metal ions on the membrane surface to form fouling, and ensure the membrane water production.

[0055] The working process of the rinse water treatment device in the stainless steel pickling process is as follows:

[0056] The flushing wastewater discharged from the workshop enters the sedimentation tank 101, where it stays for a certain period of time. Impurities and large particles of oxide scale in the waste acid are precipitated to the bottom of the tank and are pumped to the filter press by the first mud pump for filtration. The filter residue is collected and recovered, and the filtrate enters the primary membrane system; the supernatant in the sedimentation tank 101 flows into the primary membrane system by gravity. In the primary membrane system, the waste acid is filtered through the MBR membrane assembly to produce water to the secondary membrane system through the action of the suction pump, and insoluble substances such as SS in the waste acid are retained in the primary membrane tank 201. After a certain period of time, it is pumped to the filter press by the second mud pump for filtration treatment; the waste acid in the first circulation tank 301 is transported to the first large flow filter by the first lifting pump 306 for fine filtration again (filter pore size 5um), and enters the first high-pressure pump 308. After being pressurized at 308, it enters the first membrane system 302; the produced water (clean water) produced after being filtered through the seawater desalination membrane is measured by the first produced water electromagnetic flowmeter 317 and then collected for reuse; part of the concentrated water flows back to the first circulation tank 301, and part of it is discharged to the second circulation tank 401; the material in the second circulation tank 401 is transported by the second booster pump 404 to the second filter 405 for precision filtration (filtration pore size 5um), and enters the second high-pressure pump 406, and is pressurized by the second high-pressure pump 406 to enter the second membrane system 402, the produced water produced by the second membrane system 402 is measured by the second produced water electromagnetic flowmeter 413 and then collected for reuse, and part of the concentrated water enters the second circulation tank 401 for circulation after being distributed, and part of it is discharged and collected by the second concentrated water electromagnetic flowmeter 411 and then enters the APU mixed acid regeneration system.

[0057] This solution is to use physical processes to concentrate the flushing water and filter it using the characteristics of various membranes. The metal ions are enriched and concentrated, the free acid in the flushing water is selectively permeated, and the resources in the flushing water are recovered. No reagents are added during the treatment process, and no secondary sludge is generated. The treatment process is purely physical and does not cause the volume of the material to expand. The treatment device can be used as a supporting system for the APU mixed acid regeneration system. The system has low operating costs, simple operation, high degree of automation, small footprint, high metal ion removal rate, and high acid recovery rate.

[0058] The above are only embodiments of the utility model. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field to which the utility model belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement the scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for the ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the utility model, several deformations and improvements can be made, which should also be regarded as the protection scope of the utility model, and these will not affect the effect of the implementation of the utility model and the practicality of the patent.

Claims

1. A device for treating flushing water in a stainless steel pickling process, characterized in that: include: Pretreatment unit, primary membrane unit, secondary membrane unit, tertiary membrane unit; The pre-processing unit comprises: Sedimentation tank, used to receive and settle solid impurities in the flushing water; A first sewage discharge device, connected to the sedimentation tank, for discharging impurities; The primary membrane unit comprises: A primary membrane tank connected to the sedimentation tank and used to filter suspended particles in the flushing water; A second sewage discharge device, connected to the primary membrane pool, for discharging impurities; The secondary membrane unit comprises: A first circulation tank is connected to the primary membrane pool; The first membrane system is connected to the first circulation tank, and the first membrane system includes: a first produced water discharge branch and a first concentrated water discharge branch, and the first produced water discharge branch is used to discharge the regenerated reuse water; the three-stage membrane unit includes: a second circulation tank, connected to the first concentrated water discharge branch, and used for receiving concentrated water discharged from the first concentrated water discharge branch; The second membrane system is communicated with the second circulation tank, and the second membrane system comprises: a second produced water discharge branch, and the second produced water discharge branch is used to discharge the regenerated acid.

2. The device for treating flushing water in the stainless steel pickling process according to claim 1, characterized in that: The first sewage discharge device comprises: a first sludge pump, the first sludge pump connects the sedimentation tank with the filter press; The second sewage discharge device includes: a second sludge pump, the second sludge pump connects the primary membrane pool with the above-mentioned filter press, and the discharge port of the filter press is connected with the primary membrane pool.

3. The device for treating flushing water in the stainless steel pickling process according to claim 1, characterized in that: The primary membrane unit further comprises: an aeration pipe, which is connected to the primary membrane pool and is used for aeration and flushing of the filter membrane in the primary membrane pool.

4. The device for treating flushing water in the stainless steel pickling process according to claim 1, characterized in that: The secondary membrane unit also includes: a first liquid level gauge, a first lifting pump, a first pressure sensor assembly, a first filter, and a first high-pressure pump. The first liquid level gauge is installed in the first circulation tank. The first circulation tank is connected to the first membrane system through the first lifting pump, the first filter, and the first high-pressure pump. The first pressure sensor assembly is connected to the pipeline of the secondary membrane unit.

5. The device for treating flushing water in the stainless steel pickling process according to claim 1, characterized in that: The three-stage membrane unit also includes: a second liquid level gauge, a second lifting pump, a second pressure sensor assembly, a second filter, and a second high-pressure pump. The second liquid level gauge is installed in the second circulation tank. The second circulation tank is connected to the second membrane system through the second lifting pump, the second filter, and the second high-pressure pump. The second pressure sensor assembly is connected to the pipeline of the three-stage membrane unit.

6. The device for treating flushing water in the stainless steel pickling process according to claim 1, characterized in that: The secondary membrane unit also includes: a first concentrated water return branch, connecting the concentrated water outlet of the first membrane system with the first circulation tank, and used for returning the concentrated water to the first circulation tank; The first concentrated water quick discharge branch connects the concentrated water outlet of the first membrane system with the first circulation tank, and is used for quickly discharging the concentrated water to the first circulation tank.

7. The device for treating flushing water in the stainless steel pickling process according to claim 6, characterized in that: The three-stage membrane unit also includes: A second concentrated water return branch, connecting the concentrated water outlet of the second membrane system with the second circulation tank, for returning the concentrated water to the second circulation tank; A second concentrated water quick discharge branch, connecting the concentrated water outlet of the second membrane system with the second circulation tank, for quickly discharging the concentrated water to the second circulation tank; The second concentrated water discharge branch connects the concentrated water outlet of the second membrane system to the spent acid regeneration system, and is used to discharge the concentrated water to the spent acid regeneration system.

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