WO2021223441A1

WO2021223441A1 - Strip-steel mixed-acid pickling system

Info

Publication number: WO2021223441A1
Application number: PCT/CN2020/136488
Authority: WO
Inventors: 贾鸿雷; 乔军; 李春明; 周志辉
Original assignee: 中冶南方工程技术有限公司
Priority date: 2020-05-05
Filing date: 2020-12-15
Publication date: 2021-11-11
Also published as: CN212640621U

Abstract

Provided is a strip-steel mixed-acid pickling system, comprising a multi-stage rinsing and scrubbing tank (3), a plurality of mixed-acid pickling tanks (1, 2), and a hot air dryer (17) used for drying the strip steel after cleaning; each of the mixed-acid pickling tanks (1, 2) and the plurality of rinsing and scrubbing tanks (3) in the multi-stage rinsing and scrubbing tank (3) are arranged in sequence along the direction of conveyance of the strip steel; the mixed-acid pickling tank (2) located at the end of each of the mixed-acid pickling tanks (1, 2) is docked with the rinsing and scrubbing tank (3) at the first position of the multi-stage rinsing and scrubbing tank (3); the hot air dryer (17) is arranged on the side of the rinsing and scrubbing tank (3) at the end of the multi-stage rinsing and scrubbing tank (3) away from the mixed-acid pickling tank (1, 2). The strip-steel mixed-acid pickling system uses a multi-stage rinsing and scrubbing tank (3) and a plurality of mixed-acid pickling tanks (1, 2) to treat strip steel, to obtain clean strip steel, which is then dried by means of a hot air dryer (17), such that the strip steel can be applied to the subsequent process more quickly, improving operating efficiency.

Description

Strip steel mixed acid pickling system

Technical field

The utility model relates to the technical field of surface treatment of metallurgical plates and strips, in particular to a strip steel mixed acid pickling system.

Background technique

A layer of oxide scale is formed on the surface of stainless steel during rolling or annealing. The oxide scale is composed of chromium iron oxide, iron oxide and other alloying element oxides. These oxides usually contain Cr ₂ O ₃ and spinel FeO·Cr ₂ O ₃ (ie FeCr ₂ O ₄ ) structures, which are black or blue-green, octahedral equiaxed crystals, and do not dissolve in 80 ℃ temperature. Inorganic acids such as H ₂ SO ₄ , HCL or HNO _3. It is difficult to remove the oxide scale with only a single acid, so mixed acid pickling is usually used.

However, the existing mixed acid pickling has the following defects:

1. The existing mixed acid pickling process is not clean, and the strip steel is not dried after the cleaning, and the wet strip cannot be directly carried out to the next process.

2. In the process of mixed acid pickling, some metal oxides and metal-containing deposits will be produced. When a certain production accumulation is reached, the deposits will accumulate into acid mud. If the acid sludge is not removed in time, it will not only accumulate in tanks, tanks, valves, pipelines, low-lying and dead areas, causing equipment and pipeline blockages, affecting production, but also attaching to the surface of the heat exchanger, causing uneven heating Even partial overheating of the heat exchanger accelerates the damage of the heat exchanger.

3. Since the temperature required for the mixed acid pickling process is generally 40～65℃, the ion activity in the acid solution is higher at this temperature, the pickling efficiency is higher, and the metal salt is not easy to crystallize, which requires a large amount of heat source for heating, which increases Production energy costs.

4. As the temperature increases, the volatility of the mixed acid increases, and the mixed acid and the corresponding water are consumed; in addition, due to the accumulation of sediment in the conventional pickling process, it is necessary to drain the liquid from the bottom of the online tank and the bottom of the mixed acid circulation tank to the waste water pit regularly. The mixed acid and corresponding water are consumed; the rinsing and scrubbing process of the mixed acid pickling tail will affect the cleaning effect if the ion concentration in the medium exceeds the standard after a certain amount of strip steel is processed, and new water needs to be supplemented regularly; the mixed acid mist contains a certain amount of nitrogen oxides , The mist of mixed acid needs to be absorbed and treated by the acid mist purification system in order to meet the emission requirements in the national standard, and it also needs to be supplemented with new water regularly.

5. The rinsing and brushing process of the mixed acid pickling tail needs to use desalinated water, because if the chloride ion content in the surface residue of the strip is high, it can penetrate the oxide film and work with the steel matrix to generate soluble corrosion products, thus Pitting corrosion occurs locally on the steel surface.

Utility model content

The purpose of the utility model is to provide a strip steel mixed acid pickling system, which can at least solve part of the defects in the prior art.

In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions: a strip steel mixed acid pickling system, including multi-stage rinsing and scrubbing tanks, multiple mixed acid pickling tanks, and hot air drying for drying the strip steel after cleaning. Each of the mixed acid pickling tanks and the multiple rinsing and scrubbing tanks in the multi-stage rinsing and scrubbing tanks are arranged in sequence along the conveying direction of the strip steel; The tank is docked with the rinsing and scrubbing tank at the first position of the multi-stage rinsing and scrubbing tank; the hot-air dryer is arranged at the end of the multi-stage rinsing and scrubbing tank, and the rinsing and scrubbing tank is far away from the mixed acid and pickling tank. One side.

Furthermore, the bottom of each of the mixed acid pickling tanks and the bottom of each of the rinsing and scrubbing tanks are both tapered in a tapered structure, and each of the mixed acid pickling tanks is provided with a spray pipe at the bottom of the tank. road.

Further, each of the mixed acid pickling tanks is a shallow jet turbulent flow pickling tank.

Further, it also includes a multi-stage rinsing and scrubbing system circulation tank for receiving the cleaning liquid discharged from the multi-stage rinsing and scrubbing tanks, and a plurality of mixed acid circulation tanks for receiving the cleaning liquid discharged from each of the mixed acid pickling tanks. The mixed acid circulation tank is configured in a one-to-one correspondence with each of the mixed acid pickling tanks, and the multi-stage rinsing and scrubbing system circulation tank is cyclically connected to the multi-stage rinsing and scrubbing tank through a multi-stage rinsing and scrubbing circulation pump, and each of the mixed acid cycles is The tank is in cyclic communication with the corresponding mixed acid pickling tank through a mixed acid circulating pump.

Further, it also includes a mixed acid purification device for purifying the cleaning liquid discharged from the multi-stage rinsing and scrubbing tank and the mixed acid and acid washing tank, the discharge port of the circulation tank of the multi-stage rinsing and scrubbing system, and each of the mixed acid cycles The liquid discharge ports of the tank are all connected with the liquid inlet of the mixed acid purification device, and the liquid inlet of each mixed acid circulation tank is connected with the liquid discharge port of the mixed acid purification device.

Further, each of the pipelines connecting the mixed acid circulation pump to the mixed acid pickling tank is provided with a mixed acid heat exchanger.

Further, it also includes an exhaust gas waste heat boiler in the furnace zone of the unit that provides heat sources for the hot air dryer, the multi-stage rinsing and scrubbing tank, and each of the mixed acid heat exchangers.

Further, it also includes an acid mist washing tower for treating the multi-stage rinsing and scrubbing tanks and the acid mist generated by each of the mixed acid pickling tanks during operation, and the purified wastewater from the acid mist washing tower is sent to the Multi-stage rinsing and scrubbing tank.

Furthermore, it also includes a mist separator, which is in communication with the exhaust port of the acid mist washing tower, and the mist separator returns the liquid produced by the mist separation to the acid mist washing tower middle.

Further, the rinsing and scrubbing tank at the end of the multi-stage rinsing and scrubbing tank is a condensed water rinsing and scrubbing tank that uses condensed water generated by heat exchange of waste heat steam for cleaning.

Compared with the prior art, the beneficial effects of this utility model are:

1. Multi-stage rinsing and scrubbing tanks and multiple mixed acid pickling tanks are used to process strip steel, and clean strip steel can be obtained, and then dried by hot air dryer, which can make the strip steel more quickly used in the next Process, improve work efficiency.

2. By designing each of the mixed acid pickling tanks and the bottom of each of the rinsing and scrubbing tanks into a conical structure, so that the acid can be drained during shutdown; in addition, the mixed acid pickling tank adopts a shallow type Jet turbulent acid pickling tank, during operation, strong turbulence prevents acid sludge produced by the reaction of acid and strip steel from depositing on the bottom of the tank. It is also possible to set up a jet pipeline at the bottom of the mixed acid pickling tank to pass the jet stream It can also avoid the clogging caused by the deposition of acid mud.

3. The use of multi-stage rinsing and scrubbing system circulation tanks, mixed acid circulation tanks, multi-stage rinsing and scrubbing circulation pumps and mixed acid circulation pumps can realize the recycling of cleaning liquid, and then recycle their respective media.

4. The mixed acid purification device can be used to purify the treated cleaning liquid, and the purified liquid will be gravity returned to the corresponding circulation tank, avoiding the accumulation of sediment into acid mud, and the pipeline and equipment will not be damaged due to blockage. Or affect production, especially if there are no deposits in the heat exchanger, the heat exchange efficiency is improved, and the life of the mixed acid heat exchanger is greatly prolonged; in addition, combined with the above cycle, the mixed acid pickling, multi-stage rinsing and scrubbing are no longer needed. After the waste liquid is discharged according to the production situation, the original acid and new water are added to prepare to avoid the loss of process media and energy media.

5. The heat source used in the hot air dryer, multi-stage rinsing and scrubbing tank and each mixed acid heat exchanger comes from the steam produced by the waste heat boiler, because the heating of the furnace area generally starts before production, when the exhaust gas of the furnace area reaches a certain temperature, it is enough to use The waste heat boiler produces steam, and the entire steam unit can be self-produced and used without the need for an external heat source.

6. In order to meet the requirement of absorbing the soluble acid in the acid mist, an acid mist washing tower is used for treatment. The washing tower can be a multi-stage countercurrent absorption tower structure. The acid mist purification system uses desalinated water or waste heat steam to exchange heat for condensation. Water or industrial water that meets the requirements, the new water flow rate is 0.5-2m ³ /h, and the condensate accumulated in the acid mist pipes, mist separators, etc. are all returned to the acid mist purification tower, so that the acid mist purification wastewater has a stable process It can be transported to the multi-stage rinsing and scrubbing system as make-up water. In the multi-stage rinsing and scrubbing system, the make-up water overflows step by step against the running direction of the strip. When the saturated concentration is reached, it can be transported to the mixed acid circulation tank to make up for the loss caused by the evaporation of the cleaning liquid.

7. Set the rinsing and scrubbing tank at the end of the multi-stage rinsing and scrubbing tank as a condensed water rinsing and scrubbing tank that uses the condensed water generated by the heat exchange of waste heat steam to clean, which can meet the requirements for the cleanliness of the strip surface. The condensed water comes from If the condensate water generated by the heat exchange of the waste heat steam is insufficient, the demineralized water is used, which saves the consumption of demineralized water.

Description of the drawings

Figure 1 is a schematic diagram of a strip steel mixed acid pickling system provided by an embodiment of the utility model.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, not all implementations. example. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the scope of protection of the present utility model.

Please refer to Fig. 1, an embodiment of the utility model provides a strip steel mixed acid pickling system, which includes a multi-stage rinsing and scrubbing tank, a plurality of mixed acid pickling tanks, and a hot air dryer for drying the strip steel after cleaning. The mixed acid pickling tank and the multiple rinsing and scrubbing tanks in the multi-stage rinsing and scrubbing tanks are all arranged in sequence along the conveying direction of the strip steel; The first rinsing and scrubbing tank of the multi-stage rinsing and scrubbing tank is docked; the hot-air dryer is arranged at the end of the multi-stage rinsing and scrubbing tank on the side away from the mixed acid and pickling tank. In this embodiment, after the multi-stage rinsing and scrubbing tank 3 finishes the cleaning process of the strip steel, the hot air dryer 17 then performs the drying process on the strip steel. Multi-stage rinsing and scrubbing tanks and multiple mixed acid pickling tanks are used to process the strip steel to obtain a clean strip, which can then be dried by a hot air dryer, so that the strip can be used more quickly in the next process. Improved work efficiency. Preferably, direct heating or indirect heating can be used. The condensed water generated after the indirect heat exchange of the steam is collected in a condensed water tank, and the condensed water is recycled for use.

As an optimized scheme of the embodiment of the present utility model, please refer to Fig. 1. The bottom of each of the mixed acid pickling tank and the bottom of each of the rinsing and washing tanks are tapered structures, and both are tapered structures, preferably , The bottom of each of the mixed acid pickling tanks is provided with an injection pipeline. By designing the bottom of each of the mixed acid pickling tank and each of the rinsing and scrubbing tanks into a tapered structure, it is convenient for the acid liquid to be emptied when the machine is shut down. As for the number of mixed acid pickling tanks and the number of stages used in the multi-stage rinsing and scrubbing tank 3 can be set according to actual conditions, this embodiment does not limit this, preferably, as shown in Figure 1, this embodiment adopts Two mixed acid pickling tanks and five-stage rinsing and scrubbing tanks. In order to facilitate the distinction, the two mixed acid pickling tanks are defined as the first mixed acid pickling tank 1 and the second mixed acid pickling tank 2, which are transported along the strip The directions are arranged in sequence, and the same five-stage rinsing and scrubbing tanks are arranged in sequence along the transportation direction of the strip. Preferably, the mixed acid pickling tank can adopt a shallow jet turbulent flow pickling tank. During operation, the strong turbulence prevents the acid sludge produced by the reaction of the acid solution and the strip steel from depositing on the bottom of the tank. In addition, it can also be used in the mixed acid pickling. The bottom of the tank is provided with an injection pipe d, which can also avoid clogging caused by the deposition of acid sludge through the injection of liquid flow, thereby better solving the existing defects.

As an optimized scheme of the embodiment of the present utility model, please refer to FIG. 1. The system also includes a multi-stage rinsing and scrubbing system circulation tank 6 for receiving the cleaning liquid discharged from the multi-stage rinsing and scrubbing tank 3, and a circulation tank 6 for receiving each of the A plurality of mixed acid circulation tanks for the cleaning liquid discharged from the mixed acid pickling tank, each of the mixed acid circulation tanks is arranged in a one-to-one correspondence with each of the mixed acid pickling tanks, and the multi-stage rinsing and scrubbing system circulation tank 6 passes through a multi-stage rinsing and scrubbing cycle The pump 10 is in cyclic communication with the multi-stage rinsing and scrubbing tank 3, and each of the mixed acid circulation tanks is in cyclic communication with the corresponding mixed acid and acid washing tank through a mixed acid circulation pump. In this embodiment, there are also two mixed acid circulation pumps, which are defined as the first mixed acid circulation pump 8 and the second mixed acid circulation pump 9 respectively, which are connected to the first mixed acid acid pickling tank 1 and the second mixed acid acid pickling tank mentioned above. 2 Corresponding configuration. The multi-stage rinsing and scrubbing system circulation tank 6 and the mixed acid circulation tank can realize the recycling of the cleaning liquid to make full use of the performance of the cleaning liquid. Specifically, the medium in the mixed acid pickling tank and the multi-stage rinsing and scrubbing tank 3 after operation Respectively, they are combined to the multi-stage rinsing and scrubbing system circulation tank 6 and the mixed acid circulation tank, and then combined with their corresponding circulating pumps to guide the medium to the mixed acid acid washing tank and the multi-stage rinsing and scrubbing tank 3 again, and then recycle the respective media. Preferably, the piping h to the first mixed acid circulation tank 4 and the second mixed acid circulation tank 5 is arranged at the outlet of the multi-stage rinsing and scrubbing circulation pump 10, so that the medium containing a certain amount of free acid can be transported to the first mixed acid circulation tank 4 and the second acid mixed circulation tank. The two-mix acid circulation tank 5 is recycled again.

To further optimize the above solution, please refer to FIG. 1, which also includes a mixed acid purification device 12 for purifying the multi-stage rinsing and scrubbing tank 3 and the cleaning liquid discharged from the mixed acid and acid cleaning tank, and the multi-stage rinsing and scrubbing system circulation tank 6 The liquid discharge port and the liquid discharge port of each of the mixed acid circulation tanks are connected with the liquid inlet of the mixed acid purification device 12, and the liquid inlet of each acid mixed circulation tank is connected with the liquid inlet of the mixed acid purification device 12 The drain port is connected. In this embodiment, the mixed acid purification device 12 can be used to purify the treated cleaning liquid. Among them, the medium in the multi-stage rinsing and scrubbing system circulation tank 6 and the mixed acid circulation tank is also pumped to the mixed acid purification device 12, and The position of the mixed acid purification device 12 is higher than that of the multi-stage rinsing and scrubbing system circulation tank 6 and the mixed acid circulation tank. Therefore, the purified liquid after purification can be returned to the corresponding circulation tank by gravity, thus avoiding the accumulation of sediment into acid mud. Pipes and equipment will not be damaged or affect production due to clogging. In particular, there are no deposits in the heat exchanger, the heat exchange efficiency is improved, and the life of the mixed acid heat exchanger is greatly extended. Preferably, the discharge ports of the first mixed acid circulation tank 4, the second mixed acid circulation tank 5, and the multi-stage rinsing and scrubbing system circulation tank 6 are connected to the liquid inlet of the mixed acid purification device 12 through pipeline a, and each of the mixed acid circulation tanks The liquid inlet is communicated with the liquid outlet of the mixed acid purification device 12 through the pipeline b. In addition, combined with the above cycle, the mixed acid pickling, multi-stage rinsing and scrubbing do not need to discharge the waste liquid according to the production situation, and then re-add the original acid and new water to prepare, so as to avoid the loss of process media and energy media. Preferably, the mixed acid purification device 12 may be a filtering method such as pressure filtration, suction filtration, or centrifugal filtration, which is not limited in this embodiment.

To further optimize the above scheme, please refer to Fig. 1. The pipeline connecting each of the mixed acid circulation pumps to the mixed acid pickling tank is equipped with a mixed acid heat exchanger. In this embodiment, two parallel embodiments are described, that is, the mixed acid heat exchanger can directly exchange heat. This embodiment is similar to the conventional method, and after quoting the above-mentioned mixed acid purification device 12, the heat exchange can be made There are no deposits inside the heat exchanger, the heat exchange efficiency is improved, and the life of the heat exchanger is greatly extended. There are also two mixed acid heat exchangers, which are respectively defined as the first mixed acid heat exchanger 13 and the second mixed acid heat exchanger 14, which are configured in a one-to-one correspondence with the first mixed acid heat exchange pump 8 and the second mixed acid heat exchange pump 9 respectively.

To further optimize the above scheme, please refer to Fig. 1. The system also includes a heat source for the hot air dryer 17, the multi-stage rinsing and scrubbing tank 3, and each of the mixed acid heat exchangers to provide a heat source for the exhaust gas waste heat boiler in the furnace zone of the unit. In this embodiment, the heat source used by the hot air dryer 17, the multi-stage rinsing and scrubbing tank 3, and each mixed acid heat exchanger can all come from the steam produced by the waste heat boiler X, because the heating of the furnace area generally starts before production. When the exhaust gas reaches a certain temperature, it is enough to use the waste heat boiler to generate steam, and the entire steam unit can be produced and used by itself without the need for an external heat source. As for the waste heat boiler X, which is a commonly used waste heat utilization equipment in this field, its specific working principle will not be detailed here.

As an optimized scheme of the embodiment of the present utility model, please refer to Figure 1. The system also includes an acid mist washing tower for processing the multi-stage rinsing and scrubbing tank 3 and the acid mist generated by each of the mixed acid pickling tanks during operation 7. The purified wastewater from the acid mist washing tower 7 is sent to the multi-stage rinsing and scrubbing tank 3 through a pipeline. In this embodiment, in order to meet the requirement of absorbing the soluble acid in the acid mist, the acid mist washing tower 7 is used for treatment. The washing tower is preferably a multi-stage countercurrent absorption tower structure, and the water in the acid mist purification adopts desalted water or waste heat. Condensate water generated by steam heat exchange or industrial water that meets the requirements (the water can be added to the acid mist scrubber 7 through the new water pipe f), the new water flow rate is 0.5-2m ³ /h, and the mist discharge pipe e, mist The condensate accumulated in the drip separator 16 is all returned to the acid mist purification tower, so that the acid mist purification wastewater with a stable process can be transported to the multi-stage rinsing and scrubbing system as supplementary water, and the supplementary water is gradually reversed in the multi-stage rinsing and scrubbing system. Overflow in the direction of operation, when reaching the saturation concentration, it can be transported to the mixed acid circulation tank to make up for the loss caused by the evaporation of the mixed acid liquid. In addition, the purified wastewater is first returned to the multi-stage rinsing and scrubbing system circulation tank 6 (specifically, it can be conducted through the pipeline g), and then sent from the circulation tank to the mixed acid pickling tank and the multi-stage rinsing and scrubbing tank 3. Preferably, the acid mist washing tower 7 is provided with an acid mist purification circulating pump 11 to realize its own circulation. Preferably, a mist exhaust fan 15 is also provided between the mist separator 16 and the acid mist washing tower 7.

To further optimize the above solution, please refer to FIG. 1. The system also includes a mist separator 16, which communicates with the exhaust port of the acid mist scrubber 7, and the mist separator 16 also There is a liquid discharge pipe c for returning the liquid produced by the separation of mist droplets to the acid mist washing tower 7. In this embodiment, the droplet separator 16 can separate liquid, and the liquid can be returned to the acid mist washing tower 7 through the drain pipe c as supplemental water. In addition, there is a drain pipe c connecting the acid mist scrubber 7 and another mist separator.

As an optimized solution of the embodiment of the present utility model, please refer to FIG. In this embodiment, the rinsing and scrubbing tank at the end of the multi-stage rinsing and scrubbing tank 3 is set as a condensed water rinsing and scrubbing tank that uses condensed water generated by the heat exchange of waste heat steam for cleaning, which can meet the requirements for the cleanliness of the strip surface. The condensed water comes from the condensed water produced by the heat exchange of the waste heat steam. If the condensed water is insufficient, then desalinated water is used, which saves the consumption of desalinated water.

At this point, this system avoids the waste of process media and energy media caused by the waste of single processes such as mixed acid pickling, multi-stage rinsing and scrubbing, and acid mist purification. There is no need to send heat sources outside during normal production, and the consumption of new water is also large. The range is reduced, the process medium is recycled, and the production cost is greatly reduced. In addition, the system is open source and throttling, which saves the amount of energy medium and reduces the system's emissions or even no emissions.

Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it will be understood that various changes and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. , Substitutions and modifications, the scope of the present invention is defined by the appended claims and their equivalents.

Claims

A strip steel mixed acid pickling system, which is characterized in that it comprises a multi-stage rinsing and scrubbing tank, a plurality of mixed acid pickling tanks, and a hot air dryer for drying strip steel after cleaning, each of the mixed acid pickling tanks and the The multiple rinsing and scrubbing tanks in the multi-stage rinsing and scrubbing tanks are all arranged in sequence along the conveying direction of the strip steel; The first rinsing and scrubbing tank is docked; the hot air dryer is arranged at the end of the multi-stage rinsing and scrubbing tank on the side of the rinsing and scrubbing tank away from the mixed acid and pickling tank.
The strip steel mixed acid pickling system according to claim 1, characterized in that: the bottom of each of the mixed acid pickling tank and the bottom of each of the rinsing and scrubbing tanks are both cone-shaped. Shaped structure, each of the mixed acid pickling tanks is provided with injection pipes at the bottom of the tank.
The strip steel mixed acid pickling system according to claim 1, wherein each of the mixed acid pickling tanks is a shallow jet turbulent flow pickling tank.
The strip steel mixed acid pickling system according to claim 1, characterized in that it further comprises a multi-stage rinsing and scrubbing system circulation tank for receiving the cleaning liquid discharged from the multi-stage rinsing and scrubbing tank, and a circulation tank for receiving each plant A plurality of mixed acid circulation tanks for the cleaning liquid discharged from the mixed acid pickling tank, each of the mixed acid circulation tanks is arranged in a one-to-one correspondence with each of the mixed acid pickling tanks, and the multi-stage rinsing and scrubbing system circulation tank passes through a multi-stage rinsing and scrubbing cycle The pump is in cyclic communication with the multi-stage rinsing and scrubbing tanks, and each of the mixed acid circulation tanks is cyclically connected with the corresponding mixed acid and acid washing tank through a mixed acid circulation pump.
A strip steel mixed acid pickling system according to claim 4, characterized in that it further comprises a mixed acid purification device for purifying said multi-stage rinsing and scrubbing tank and the cleaning liquid discharged from said mixed acid pickling tank, said The discharge port of the multi-stage rinsing and scrubbing system circulation tank and the discharge port of each of the mixed acid circulation tanks are connected with the liquid inlet of the mixed acid purification device, and the liquid inlet of each mixed acid circulation tank is connected to the The liquid discharge port of the mixed acid purification device is connected.
A strip steel mixed acid pickling system according to claim 4 or 5, characterized in that: a mixed acid heat exchanger is provided on the pipeline connecting each of the mixed acid circulating pumps to the mixed acid pickling tank.
The strip steel mixed acid pickling system according to claim 6, characterized in that it further comprises an internal furnace for providing heat sources for the hot air dryer, the multi-stage rinsing and scrubbing tank, and each of the mixed acid heat exchangers. District exhaust gas waste heat boiler.
The strip steel mixed acid pickling system according to claim 1, characterized in that it further comprises acid mist for processing the acid mist generated by the multi-stage rinsing and scrubbing tanks and each of the mixed acid pickling tanks during operation. The washing tower, the purified wastewater of the acid mist washing tower is sent to the multi-stage rinsing and scrubbing tank through a pipeline.
The strip steel mixed acid pickling system according to claim 8, characterized in that it further comprises a mist separator, the mist separator is in communication with the exhaust port of the acid mist washing tower, and the mist The droplet separator returns the liquid produced by the separation of the mist droplets to the acid mist washing tower.
The strip steel mixed acid pickling system according to claim 1, wherein the rinsing and scrubbing tank at the end of the multi-stage rinsing and scrubbing tank is condensed water for cleaning using condensed water generated by heat exchange of waste heat steam. Rinse the scrubbing tank.