Special alkali liquid purification system

Abstract

The purpose of the present invention is to provide a dedicated purification system for alkali solution, comprising a circulation tank 3, wherein the circulation tank 3 is divided into a turbid liquid area A and a clear liquid area B by a partition; an iron removal module and an oil removal module, which can greatly reduce the iron concentration in the cleaning / alkali solution, not only improving the cleaning effect of the strip surface, but also greatly reducing the probability of iron entering the annealing furnace, greatly improving the furnace condition, preventing the occurrence of nodules, and further ensuring the surface quality of the strip; greatly reducing the oil concentration in the cleaning / alkali solution, minimizing the influence of the oil on the cleaning effect, and improving the cleaning effect of the alkali solution; effectively preserving the functional components in the cleaning / alkali solution, and improving the performance of the alkali solution; greatly reducing the discharge of alkali solution and COD, and greatly reducing the environmental load; greatly reducing the frequent active discharge caused by excessive iron or oil content, and greatly improving the utilization efficiency of the alkali solution.

Description

Technical Field

[0001] The invention relates to a special purification system for alkali liquor. Background Art

[0002] The cleaning liquid / alkali solution (hereinafter referred to as "alkali solution") in the circulation system of the cold rolling processing line of the steel plant is used to wash or assist the brush roller to clean the residual oil and iron left over from the previous process on the surface of the strip. If the iron and oil washed off remain in the cleaning liquid / alkali solution, they will still be harmful. Therefore, they need to be removed from the cleaning / alkali solution, and the concentration should be as low as possible.

[0003] At present, the existing production line treatment solutions only have relatively mature iron removal solutions, but no mature oil removal solutions; and:

[0004] 1. Existing iron removal solutions:

[0005] 1) Most of the iron removal equipment uses rod chain magnetic filters, which have low filtration accuracy, high equipment failure rate, and high moisture content of the separated iron powder, which is not conducive to the treatment of the next process;

[0006] 2) Most of the installations of magnetic filters other than rod chain magnetic filters or drum magnetic filters do not take into account the reasonable process arrangement of the pipeline system, which also makes the treatment effect of the system poor;

[0007] 2. Existing oil removal solutions / ultrafiltration solutions:

[0008] The original intention of this solution was to remove oil, which is a molecular-level filtration. However, the special properties of the alkali solution in the circulation system - "high iron content, high suspended matter, and high turbidity" - caused it to be "troubled" by iron powder and suspended matter, and it was unable to filter out the oil in a targeted manner, and could not operate stably for a long time. At the same time, this solution requires backwashing, which has the disadvantage of secondary pollution;

[0009] 3. Filter material filtration solutions:

[0010] This technical solution does not have a clear direction of "iron removal" or "oil removal". It only removes iron powder and suspended matter while taking away some oil wrapped on the surface of iron powder and in the sludge mixed with suspended matter. There is still a large amount of oil free in the alkali solution that has not been removed. Moreover, in the filter material filtration solution, the filtration accuracy of the filter material is mostly above 50 microns, which is basically higher than the main particle size range of iron powder of 5 to 35 microns, and the filtration accuracy of iron powder is not high. At the same time, this solution requires backwashing, which has the disadvantage of secondary pollution.

[0011] Therefore, the concentrations of iron and oil in the circulation tank of the current circulation system are very high, which not only ① leads to poor cleaning effect in the cleaning section and affects the process cleaning effect, but also causes iron to enter the subsequent process, endangering the surface quality of the strip and worsening the condition of the annealing furnace; ② the effective components in the alkali solution are consumed by the oil, resulting in low utilization efficiency and high energy consumption; ③ and the frequent discharge of alkali solution leads to a large alkali solution discharge load and COD discharge load. Summary of the invention

[0012] An object of the present invention is to provide a special purification system for alkali solution.

[0013] According to one aspect of the present invention, a dedicated purification system for alkali liquid is provided, the dedicated purification system for alkali liquid comprising:

[0014] A circulation tank 3, wherein the circulation tank 3 is divided into a turbid liquid area A and a clear liquid area B by a partition;

[0015] A main line reflux port b is arranged near the partition side of the turbid liquid area A, and the main line reflux port b is arranged in the middle and lower part of the turbid liquid area A. The main line reflux port b is connected with the basket filter 2 and the online tank 1 in sequence through a pipeline;

[0016] An oil removal suction port c is provided in the middle and lower part of the clear liquid area B, and the oil removal suction port c is connected with the delivery pump 4 and the inline tank 1 in sequence through a pipeline;

[0017] An iron removal module, the iron removal module comprising: a rotary drum magnetic filter 7, an iron removal return port j and an iron removal suction port e, wherein the iron removal return port j is arranged at the middle and lower part of the clear liquid area B, the iron removal suction port e is arranged at the middle and lower part of the turbid liquid area A, and the iron removal return port j and the iron removal suction port e are respectively connected to the rotary drum magnetic filter 7 through pipelines;

[0018] The oil removal module comprises: a high-speed centrifugal separation device 13, a floating suction port 8 and an oil removal return port n, wherein the floating suction port 8 is arranged below the top liquid level of the clear liquid area B, and the oil removal return port n is arranged below the liquid level of the clear liquid area B, and the floating suction port 8 and the oil removal return port n are respectively connected to the high-speed centrifugal separation device 13 through pipelines.

[0019] Furthermore, in the above-mentioned alkali liquid purification system, the main line reflux port b adopts a large-radius elbow, and the large-radius elbow of the main line reflux port b is directed to the groove wall direction of the circulation tank 3 on the side away from the lower partition 17 of the turbid liquid area A, and the outlet forms a horizontal shape and forms an angle of ≤20 with the groove side wall 18 of the circulation tank 3. 0 angle.

[0020] Furthermore, in the above-mentioned alkali solution purification system, the iron removal return port j adopts a large-radius elbow, and the large-radius elbow of the iron removal return port j is guided to the lower partition 17 on the side of the clear liquid area B, and forms a ≤20 0 Angle shape.

[0021] Furthermore, in the above-mentioned alkali liquid purification system, the oil removal return port n adopts a large-radius elbow, and the large-radius elbow of the oil removal return port n is directed to the groove wall of the circulation tank 3 away from the lower partition 17 side of the clear liquid area B, and forms a groove of ≤20 with the groove wall side. 0 Angle shape.

[0022] Furthermore, in the above-mentioned alkali solution purification system, the partition includes a lower partition 17 and an upper partition 16, wherein:

[0023] The lower partition 17 is arranged between the turbid liquid area A and the clear liquid area B, and the upper partition 16 is arranged on the upper side of the turbid liquid area A close to the lower partition 17. There is a gap between the upper partition 16 and the lower partition 17. The lower partition 17 is used to block the iron and suspended matter in the turbid liquid area A and allow the clear liquid to overflow to the clear liquid area B; the upper partition 16 is used to block the foam formed on the top of the turbid liquid area A in the turbid liquid area A so that it will not spread to the clear liquid area B.

[0024] Furthermore, in the above-mentioned alkali solution purification system, the iron removal module also includes a delivery pump 5, an iron removal outlet g and a regulating valve 6, wherein:

[0025] The iron removal outlet g is arranged at the bottom of the turbid liquid area A;

[0026] One end of the delivery pump 5 is connected to the iron removal suction port e through a pipeline, and the other end of the delivery pump 5 is connected to the iron removal outlet g through a pipeline;

[0027] One end of the regulating valve 6 is communicated with the common node of the delivery pump 5 and the iron removal outlet g, and the other end of the regulating valve 6 is communicated with the rotary drum magnetic filter 7 .

[0028] Furthermore, in the above-mentioned alkali solution dedicated purification system, the iron removal suction port e is arranged at the diagonal of the main line reflux port b, and the delivery pump 5 extracts dirty alkali solution from the turbid liquid area A of the circulation tank 3 with a delivery capacity of about 1.5 times the processing capacity of the rotary drum magnetic filter 7, wherein 2 / 3 of the flow rate is delivered to the rotary drum magnetic filter 7 for iron separation, and the remaining 1 / 3 of the flow rate is controlled by the regulating valve 6 and refluxed to the turbid liquid area A of the circulation tank 3 through the iron removal outlet g. The iron removal outlet g is arranged at a lower part about 200 mm away from the iron removal suction port e, so that the alkali solution at this position is fully impacted and stirred.

[0029] Furthermore, in the above-mentioned alkali solution purification system, the oil removal module also includes: a delivery pump 9, a primary filtration system 10, a buffer tank 11, a delivery pump 12, an oil storage tank 14 and a slag tank 15, wherein:

[0030] One end of the delivery pump 9 is connected to the floating suction port 8 through a pipeline, and the other end of the delivery pump 9 is connected to the primary filtration system 10 through a pipeline;

[0031] One end of the buffer tank 11 is connected to the primary filtration system 10 through a pipeline, and the other end of the buffer tank 11 is connected to the delivery pump 12 through a pipeline;

[0032] One end of the high-speed centrifugal separation device 13 is connected to the delivery pump 12 through a pipeline, and the other end of the high-speed centrifugal separation device 13 is connected to the oil removal return port n through a pipeline;

[0033] The oil storage tank 14 is connected to the high-speed centrifugal separation device 13 through a pipeline;

[0034] The slag tank 15 is connected to the primary filtration system 10 and the high-speed centrifugal separation equipment 13 through pipelines.

[0035] Furthermore, in the above-mentioned alkali solution dedicated purification system, the clean alkali solution output by the high-speed centrifugal separation device 13 is transported back to the clear liquid area B on the side of the circulation tank 3 away from the lower partition 17 through the oil removal return port n, and together with the clean alkali solution overflowing the lower partition 17 and the clean alkali solution filtered by the drum magnetic filter 7, after further precipitation and stable stratification in the clear liquid area B, the clearer alkali solution on the upper part will be transported by the delivery pump 4 through the pipeline to the online tank 1 for a new round of flushing / cleaning work;

[0036] The oil phase outputted from the high-speed centrifugal separation device 13 is transported to the oil storage tank 14 through a pipeline;

[0037] The slag phase outputted from the high-speed centrifugal separation device 13 is transported to the slag tank 15 of the oil removal module via a pipeline.

[0038] Furthermore, in the above-mentioned alkali solution purification system, the oil removal suction port c is arranged 100 mm below the minimum operating limit liquid level of the clear liquid area B.

[0039] Compared with the prior art, the present invention can greatly reduce the iron concentration in the cleaning / alkaline solution, which not only improves the cleaning effect of the strip surface, but also greatly reduces the probability of iron entering the annealing furnace, greatly improves the furnace condition, prevents the occurrence of nodules, and further ensures the surface quality of the strip; greatly reduces the oil concentration in the cleaning / alkaline solution, minimizes the influence of the oil on the cleaning effect, and improves the cleaning effect of the alkaline solution; effectively preserves the functional components in the cleaning / alkaline solution, and improves the performance of the alkaline solution; greatly reduces the discharge of alkaline solution and COD, and reduces the environmental load; greatly reduces the frequent active discharge caused by excessive iron or oil content, and greatly improves the utilization efficiency of the alkaline solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0041] Figure 1 A schematic diagram showing a process flow of a dedicated alkali solution purification system according to an embodiment of the present invention;

[0042] Figure 2 Show Figure 1 Top view of the circulation tank.

[0043] The same or similar reference numerals in the drawings represent the same or similar components. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0045] The purpose of the present invention is to: reduce the iron content in the alkali solution to a minimum under the premise that the amount of foam generated is as low as possible, so as to eliminate the influence of the iron content on the surface quality of the strip steel and reduce the influence of the iron content on the condition of the annealing furnace; reduce the oil content in the alkali solution to a minimum under the premise that the amount of foam generated is as low as possible, so as to reduce ① the probability of the effective components of the cleaning / alkali solution being destroyed (improving efficiency: improving the cleaning effect of the cleaning / alkali solution); ② reducing the isolation between the cleaning / alkali solution and the strip steel due to its existence, thereby negatively affecting the cleaning effect; ③ reducing the large-scale frequent active discharge of the alkali solution due to its high concentration and the large-scale discharge of COD caused by it (improving efficiency: improving the utilization efficiency of the cleaning / alkali solution; reducing emissions: reducing COD emissions).

[0046] In view of the current technological status and the technological goal of removing iron and oil and reducing their concentration to the lowest, various plans were analyzed and evaluated in a targeted manner. Finally, the most scientific, reasonable and most feasible plan - "alkaline solution special purification system" was selected and implemented.

[0047] like Figures 1-2As shown, a dedicated purification system for alkali liquid, wherein the dedicated purification system for alkali liquid comprises:

[0048] A circulation tank 3, wherein the circulation tank 3 is divided into a turbid liquid area A and a clear liquid area B by a partition;

[0049] A main line reflux port b is arranged near the partition side of the turbid liquid area A, and the main line reflux port b is arranged in the middle and lower part of the turbid liquid area A. The main line reflux port b is connected with the basket filter 2 and the online tank 1 in sequence through a pipeline;

[0050] An oil removal suction port c is provided in the middle and lower part of the clear liquid area B, and the oil removal suction port c is connected with the delivery pump 4 and the inline tank 1 in sequence through a pipeline;

[0051] An iron removal module, the iron removal module comprises: a rotary drum magnetic filter 7, an iron removal return port j and an iron removal suction port e, wherein the iron removal return port j is arranged at the middle and lower part of the clear liquid area B, the iron removal suction port e is arranged at the middle and lower part of the turbid liquid area A, and the iron removal return port j and the iron removal suction port e are respectively connected to the magnetic rotary drum magnetic filter 7 through pipelines;

[0052] The oil removal module comprises: a high-speed centrifugal separation device 13, a floating suction port 8 and an oil removal return port n, wherein the floating suction port 8 is arranged below the top liquid level of the clear liquid area B, and the oil removal return port n is arranged below the liquid level of the clear liquid area B, and the floating suction port 8 and the oil removal return port n are respectively connected to the high-speed centrifugal separation device 13 through pipelines.

[0053] In one embodiment of the alkali liquid purification system of the present invention, the main line reflux port b adopts a large-radius elbow, and the large-radius elbow of the main line reflux port b is directed to the groove wall direction of the circulation tank 3 away from the lower partition 17 side of the turbid liquid area A, and the outlet forms a horizontal shape and forms a groove side wall 18 of the circulation tank 3 of ≤20 0 angle.

[0054] In one embodiment of the alkali solution purification system of the present invention, the iron removal return port j adopts a large arc elbow, and the large arc elbow of the iron removal return port j is guided to the lower partition 17 on the side of the clear liquid area B, and forms a ≤20 0 Angle shape.

[0055] In one embodiment of the alkali liquid purification system of the present invention, the oil removal return port n adopts a large arc elbow, and the large arc elbow of the oil removal return port n is directed to the groove wall of the circulation tank 3 away from the lower partition 17 side of the clear liquid area B, and forms a groove of ≤20 with the groove wall side. 0 Angle shape.

[0056] In one embodiment of the alkali solution purification system of the present invention, the partition includes a lower partition 17 and an upper partition 16, wherein:

[0057] The lower partition 17 is arranged between the turbid liquid area A and the clear liquid area B, and the upper partition 16 is arranged on the upper side of the turbid liquid area A close to the lower partition 17. There is a gap between the upper partition 16 and the lower partition 17. The lower partition 17 is used to block the iron and suspended matter in the turbid liquid area A and allow the clear liquid to overflow to the clear liquid area B; the upper partition 16 is used to block the foam formed on the top of the turbid liquid area A in the turbid liquid area A so that it will not spread to the clear liquid area B.

[0058] In one embodiment of the alkali solution purification system of the present invention, the iron removal module further includes a delivery pump 5, an iron removal outlet g and a regulating valve 6, wherein:

[0059] The iron removal outlet g is arranged at the bottom of the turbid liquid area A;

[0060] One end of the delivery pump 5 is connected to the iron removal suction port e through a pipeline, and the other end of the pump 5 is connected to the iron removal outlet g through a pipeline;

[0061] One end of the regulating valve 6 is communicated with the common node of the delivery pump 5 and the iron removal outlet g, and the other end of the regulating valve 6 is communicated with the rotary drum magnetic filter 7 .

[0062] In one embodiment of the alkali liquid purification system of the present invention, the iron removal suction port e is arranged at the diagonal of the main line reflux port b, and the delivery pump 5 extracts dirty alkali liquid from the turbid liquid area A of the circulation tank 3 with a delivery capacity of about 1.5 times the processing capacity of the rotary drum magnetic filter 7, wherein 2 / 3 of the flow rate is delivered to the rotary drum magnetic filter 7 for iron separation, and the remaining 1 / 3 of the flow rate is controlled by the regulating valve 6 and refluxed to the turbid liquid area A of the circulation tank 3 through the iron removal outlet g. The iron removal outlet g is arranged at a lower part 200 mm away from the iron removal suction port e, so that the alkali liquid at this position is fully impacted and stirred.

[0063] In one embodiment of the alkali liquor purification system of the present invention, the oil storage tank 14 and the slag tank 15, wherein one end of the delivery pump 9 is connected to the floating suction port 8 through a pipeline, and the other end of the delivery pump 9 is connected to the primary filtration system 10 through a pipeline;

[0064] One end of the buffer tank 11 is connected to the primary filtration system 10 through a pipeline, and the other end of the buffer tank 11 is connected to the delivery pump 12 through a pipeline;

[0065] One end of the high-speed centrifugal separation device 13 is connected to the delivery pump 12 through a pipeline, and the other end of the high-speed centrifugal separation device 13 is connected to the oil removal return port n through a pipeline;

[0066] The oil storage tank 14 is connected to the high-speed centrifugal separation device 13 through a pipeline;

[0067] The slag tank 15 is connected to the primary filtration system 10 and the high-speed centrifugal separation equipment 13 through pipelines.

[0068] In one embodiment of the alkali liquor purification system of the present invention, the clean alkali liquor outputted from the high-speed centrifugal separation device 13 is transported back to the clear liquid area B on the side of the circulation tank 3 away from the lower partition 17 through the oil removal return port n, and together with the clean alkali liquor overflowing the lower partition 17 and the clean alkali liquor filtered by the rotary magnetic filter 7, after further precipitation and stable stratification in the clear liquid area B, the clearer alkali liquor on the upper part will be transported by the delivery pump 4 through the pipeline d to the online tank 1 for a new round of flushing / cleaning work;

[0069] The oil phase outputted from the high-speed centrifugal separation device 13 is transported to the oil storage tank 14 through a pipeline;

[0070] The slag phase outputted from the high-speed centrifugal separation device 13 is transported to the slag tank 15 of the oil removal module via a pipeline.

[0071] In one embodiment of the alkali solution purification system of the present invention, the oil removal suction port c is arranged 100 mm below the lowest limit liquid level of the clear liquid area B.

[0072] Specifically, in the above iron removal module:

[0073] 1) The rotary drum magnetic filter (hereinafter referred to as "magnetic filter") is used as the core equipment of the iron removal system. The high filtration accuracy and low failure rate of this equipment enable it to better complete the key task of iron powder removal;

[0074] 2) In the process layout of the alkali solution delivery pipeline, full consideration is given to the influence of the suction port, return port, elbow shape and pipeline direction on the cleaning / alkali solution state based on the principle of fluid mechanics, and reasonable and targeted design is carried out. Specifically, first, the iron removal suction port e should be set at the bottom of the turbid liquid area A close to the iron content concentration; second, the iron removal return port j should return to the clear liquid area B, and in the form of a large arc elbow, rush to the lower partition 17 at a close distance and a small angle to enter the liquid level of the clear liquid area B, so that it can achieve the best treatment effect of "optimal iron removal effect and minimum foam generation";

[0075] 3) The delivery pump 5 extracts dirty alkali solution from the turbid liquid area A of the circulation tank 3 with a delivery volume of about 1.5 times the processing volume of the drum magnetic filter 7 (the iron removal suction port e is set at the diagonal of the main line reflux port b, about 400mm away from the bottom of the tank), wherein 2 / 3 of the flow is delivered to the drum magnetic filter 7 through the pipeline h for iron separation, and the remaining 1 / 3 of the flow is controlled by the regulating valve 6 and refluxed to the turbid liquid area A of the circulation tank 3 through the reflux pipe f and the iron removal outlet g in turn. The iron removal outlet g is set at the bottom about 200mm away from the iron removal suction port e, and the alkali solution at this position is fully impacted and stirred, so that the iron deposited at this position floats, which is conducive to the delivery pump 5 to deliver it to the magnetic filter 7 for effective separation of iron;

[0076] 4) After high-precision filtration by the magnetic filter 7, the iron or iron wrapped in oil sludge is separated and distributed to the iron powder slag bucket, and the clean alkali solution after filtration naturally flows back to the side of the clear liquid area B near the lower partition 17 of the circulation tank 3 through the delivery pipe i connected to the bottom of the magnetic filter 7, so that the clean alkali solution is concentrated in the clear liquid area, and is flushed to the lower partition 17 through the large arc elbow and small angle side of the port j to enter the clear liquid area B. It will be together with the clean alkali solution overflowing the lower partition 17 and the clean alkali solution after oil separation by the oil removal module, and after further precipitation and stable stratification in the clear liquid area B, the clearer alkali solution on the upper part will be delivered by the delivery pump 4 through the main line reflux delivery pipe d to the online tank 1 for a new round of flushing / cleaning work.

[0077] In the above oil removal module:

[0078] 1) The direct separation method of high-speed centrifugal separation is used to effectively separate oil and alkali solution. This method effectively avoids the disadvantages of easy pore clogging and secondary pollution in the traditional pore filtration and backwashing method, and can work continuously with high separation efficiency and good effect;

[0079] 2) In the process layout of the alkali solution conveying pipeline, full consideration is given to: first, the function of the primary filtration system 10 is set so that most of the iron content can be processed in this link, and the high-speed centrifugal separation equipment 13 can "concentrate" on the degreasing work; second, based on the principle of fluid mechanics, the floating suction port 8, the degreasing return port n, the elbow shape of the degreasing return port n and the pipeline direction are reasonably and targetedly designed in terms of the influence of the state of the alkali solution. Specifically, the floating suction port 8 should be set below the liquid level of the top of the liquid level where the oil content is relatively concentrated in the clear liquid area B, and the extraction is carried out in the form of the floating suction port 8; the degreasing return port n should return to the clear liquid area B, away from the side of the lower partition 17, and in the form of a large arc elbow of the degreasing return port n, rush to the circulation tank wall of the clear liquid area B away from the lower partition 17 at a close distance and a small angle to enter below the liquid level, so that it can achieve the best treatment effect of "optimal oil removal effect and minimum foam generation";

[0080] 3) A floating suction port 8 is provided below the liquid level of the clear liquid area B by about 150 mm, which is connected to a pipe provided at the bottom of the tank wall through a hose at the bottom, and is connected to a delivery pump 9. The alkali solution rich in oil at the top of the liquid level of the clear liquid area B passes through the floating suction port 8 and is delivered to the oil removal module by the delivery pump 9 and first enters the primary filtration system 10. After being filtered by the primary filtration system 10, most of the iron in the alkali solution, especially the large particles of iron, are processed and separated into the slag tank 15 of the oil removal module;

[0081] 4) The alkali solution treated by the primary filtration system 10 enters the buffer tank 11, and after sedimentation in the buffer tank 11 and overflow of the partition, it is transported to the high-speed centrifugal separation module equipment 13 through the delivery pump 12 for oil separation;

[0082] 5) In the high-speed centrifugal separation device 13, the alkali solution is subjected to the centrifugal force at a speed of up to 8000-12000 rpm, and the oil, clear liquid and slag phase are separated and layered, and are transported to corresponding positions through the three-phase channel in the high-speed centrifugal separation device 13:

[0083] a) The clean alkali liquid outputted from the high-speed centrifugal separation device 13 is transported back to the clear liquid area B on the side of the circulation tank 3 away from the lower partition 17 through the pipeline m, and is flushed to the tank wall of the circulation tank 3 through the large arc elbow and small angle side of the oil removal return port n to enter the clear liquid area B. It will be together with the clean alkali liquid overflowing the lower partition 17 and the clean alkali liquid filtered by the rotary magnetic filter 7. After further precipitation and stable stratification in the clear liquid area B, the clearer alkali liquid on the upper part will be transported by the delivery pump 4 through the main line reflux delivery pipe d to the online tank 1 for a new round of flushing / cleaning work;

[0084] b) The oil phase output from the high-speed centrifugal separation device 13 is transported to the oil storage tank 14 through the pipeline o under the action of the centripetal pump;

[0085] c) The slag phase outputted from the high-speed centrifugal separation device 13 is first transported to the slag box of the oil removal module after the regular slag discharge operation, and then transported to the slag tank 15 of the oil removal module through the pipeline p under the action of the pneumatic diaphragm pump;

[0086] 6) The concentrated dirty liquid in the slag tank 15 contains a large amount of suspended matter, including a small amount of fine iron, a certain amount of oil and a large amount of suspended matter. After being filtered and precipitated in the slag tank 15, the filtered alkali liquid flows back to the buffer tank 11 and re-enters the circulation process.

[0087] In the circulation tank and main circulation:

[0088] A partition is arranged in the middle of the circulation tank 3, and the partition includes a lower partition 17 and an upper partition 16, wherein the lower partition 17 is arranged between the turbid liquid area A and the clear liquid area B, and the upper partition 16 is arranged on the upper side of the turbid liquid area A close to the lower partition 17, and there is a gap between the upper partition 16 and the lower partition 17, and the lower partition 17 is used to block a large amount of iron and suspended matter in the turbid liquid area A, allowing the clear liquid to overflow to the clear liquid area B; the upper partition 16 is used to block the foam formed on the top of the turbid liquid area A in the turbid liquid area A, so as not to spread to the clear liquid area B, so as to divide the tank body into the turbid liquid area A and the clear liquid area B;

[0089] 1) In the cycle abcd, the main line reflux pipe a passes through the large arc elbow (the outlet is horizontal) of the main line reflux port b of the pipeline from the turbid liquid area close to the lower partition 17, the upper partition 16 and the side wall 18, and returns the cleaning / alkali solution that has washed / cleaned the strip steel in the line tank 1 and carries a large amount of iron and oil to the turbid liquid area A. This flow direction can form a stable horizontal circulation flow in the turbid liquid area A, and this circulation flow can prevent the iron in the alkali solution from settling to the bottom of the circulation tank 3 and depositing to the greatest extent;

[0090] 2) In the turbid liquid area A, driven by the continuous and stable circulation flow formed by the main line reflux port b, the iron content, especially the large-particle iron content, tends to move to the bottom, while the oil content tends to move to the top. Generally speaking, the upper part is clearer and the bottom is more turbid; the relatively clear alkali liquid in the upper part overflows from the top of the lower partition 17 to the clear liquid area B, and together with the clean alkali liquid filtered by the magnetic filter 7 and the clean alkali liquid after oil separation by the oil removal module, after further precipitation and stable stratification in the clear liquid area B, the clearer alkali liquid in the upper part will be transported by the delivery pump 4 through the main line reflux delivery pipe d to the online tank 1 for a new round of flushing / cleaning work;

[0091] 3) On the tank wall of the clear liquid zone B away from the lower partition 17, 100 mm below the minimum operating limit liquid level of the clear liquid zone B, a main circulation oil removal suction port c is set. This position can not only ensure that the foam on the liquid surface is not sucked into the delivery pipeline, but also ensure that the cleanest alkali liquid in the clear liquid zone is delivered to the online tank 1 through the delivery pump 4 for work, wherein the said minimum limit liquid level means that if the clear liquid zone B is lower than this liquid level, the alkali liquid special purification system will not be able to work.

[0092] In one embodiment, the working process of the present invention is as follows: during operation, the iron removal module is started before the oil removal module, and the oil removal module is started after the iron removal module has been working normally for 12 hours.

[0093] In one embodiment, the main line reflux port b, the iron removal return port j, and the oil removal return port n use large-radius elbows. Here, the process turns of the conveying pipelines a, d, h, i, k, l, and m are connected with large-radius elbows as much as possible to avoid the vertical impact caused by the 90-degree elbow and increase the generation of foam; the large-radius elbows of the main line reflux port b, the iron removal return port j, and the oil removal return port n are used as reflux pipes to enter the circulation tank 3. Among them, firstly, the large-radius elbows of the main line reflux port b, the iron removal return port j, and the oil removal return port n should be inserted into the liquid surface and cannot be suspended above the liquid surface; secondly, the large-radius elbows of the main line reflux port b, the iron removal return port j, and the oil removal return port n are guided to the tank wall and form a small angle shape with the tank wall, ≤20 0 The main line reflux port b has a large arc elbow directed to the trough wall of the circulation tank 3 in the turbid liquid area A away from the lower partition 17, and the outlet forms a horizontal shape and forms a ≤20 0 The large arc elbow of the iron removal return port j is guided to the lower partition 17 on the side of the clear liquid zone B, and forms a ≤20 side facing the lower partition 17 0 Angle shape; the large arc elbow of the oil removal return port n is directed to the groove wall of the circulation tank 3 away from the lower partition 17 side of the clear liquid area B, and forms ≤20 on the side facing the groove wall 0 Angle shape.

[0094] The iron removal module of the present invention can fully separate the iron content under the premise of suppressing the generation of foam as much as possible, so as to reduce the iron content of the alkali solution in the circulation system to the minimum, thereby eliminating its influence on the surface quality of the strip; and reducing the influence on the furnace condition caused by the iron introduced into the annealing furnace; at the same time, reducing the probability of the existence of the iron in the furnace causing the furnace roller to form nodules and thus affecting the surface quality of the strip or falling on the surface of the strip and directly affecting the surface quality of the strip. At present, the operating effect can reach an iron content of about 300ppm (original value 1000-8000ppm) of the alkali solution in the circulation tank 3.

[0095] The present invention uses an oil removal module to fully separate the oil while suppressing the generation of foam as much as possible, which can: greatly reduce the probability of the effective components of the cleaning / alkali solution being destroyed; reduce the isolation between the cleaning / alkali solution and the strip steel due to its existence, thereby reducing the negative impact on the cleaning effect; reduce the large-scale discharge of alkali solution due to its high concentration and the large-scale discharge of COD caused by it. Thereby improving the cleaning effect of alkali solution (process effect); improving the utilization efficiency of alkali solution (energy saving and emission reduction); effectively controlling the discharge of alkali solution and COD (emission reduction / environmental protection). The operating effect can reach an alkali solution oil content of 400 to 500 ppm in the circulation tank 3 (original value 1000 to 30000 ppm).

[0096] In a specific embodiment, the process is implemented by a cleaning section circulation system of a continuous annealing production line in a cold-rolled tinplate plant:

[0097] Through the iron removal module of the present invention, i.e., the iron removal system of the alkali brush circulation tank: the dirty alkali solution containing iron and oil is transported from the bottom of the turbid liquid area A of the alkali brush circulation tank 3 to the drum magnetic filter 7 through the delivery pump 5 (part of it flows back to the bottom of the tank body for backwashing to suspend the iron powder, and then as much as possible is transported to the drum magnetic filter 7), after the operation of the drum magnetic filter 7, most of the iron is separated and scraped to the iron powder slag hopper, and the clean washing / alkali solution after separation passes through the large arc elbow of the pipeline i and the port j, and flows back to the clear liquid area B of the alkali brush circulation tank 3 through the partition plate 17 under the tank wall;

[0098] Through the iron removal module of the present invention, i.e., the iron removal system of the electrolytic circulation tank: the dirty alkali solution containing iron and oil is transported from the bottom of the turbid liquid area A of the electrolytic circulation tank 3 to the rotary drum magnetic filter 7 through the delivery pump 5 (part of it flows back to the bottom of the tank body for backwashing to suspend the iron powder, and then as much as possible is transported to the rotary drum magnetic filter 7), after the operation of the rotary drum magnetic filter 7, most of the iron is separated and scraped to the iron powder slag hopper, and the clean washing / alkali solution after separation passes through the pipeline i and the large arc elbow j at the terminal, and flows back to the clear liquid area B of the electrolytic circulation tank 3 through the lower partition plate 17 of the tank wall;

[0099] Through the oil removal module of the present invention, i.e., the oil removal system of the alkali brush circulation tank: through the floating suction port 8 at the top of the liquid level of the clear liquid area B and through the pipeline k, the dirty alkali liquid with rich oil and a small amount of iron on the liquid level surface is transported from the top of the clear liquid area B of the alkali brush circulation tank 3 to the primary filter 10 module through the delivery pump 9. After the operation of the primary filter 10 equipment, most of the iron is separated, and the separated iron is scraped off to the slag tank 15 of the oil removal module. The separated dirty alkali liquid with less iron and more oil enters the buffer tank 11 of the next link of the primary filter 10 module, and after overflowing and settling through the partition in the buffer tank 11, it is transported to the high-speed centrifugal separation through the delivery pump 12. Equipment 13, after high-speed (8000 ~ 12000rpm) centrifugal separation, the dirty alkali liquid is layered: oil, clean alkali liquid, slag (including a small amount of iron, suspended matter), of which the oil is transported to the oil storage tank 14 (entering the solid waste treatment process); the clean alkali liquid passes through the pipeline m and the large arc elbow n at the terminal, passes through the tank wall away from the side of the lower partition 17, and is transported back to the clean liquid area B of the alkali brush circulation tank 3; the slag is temporarily stored in the slag box through the pipeline q and the pneumatic diaphragm pump to the slag tank 15; after accumulation and sedimentation in the slag tank 15, the supernatant overflows back to the buffer tank 11, and the remaining solid phase gradually accumulates and finally enters the solid waste treatment process.

[0100] Through the oil removal module of the present invention, i.e., the electrolytic circulation tank oil removal system: through the floating suction port 8 at the top of the liquid level of the clear liquid area B and through the pipeline k, the dirty alkali liquid with rich oil and a small amount of iron on the liquid level surface is transported from the top of the clear liquid area B of the electrolytic circulation tank 3 to the primary filtration 10 module through the delivery pump 9. After the operation of the primary filtration 10 equipment, most of the iron is separated, and the separated iron is scraped off to the slag tank 15 of the oil removal module. The separated dirty alkali liquid with less iron and more oil enters the buffer tank 11 of the next link of the primary filtration 10 module, and after overflowing and settling through the partition in the buffer tank 11, it is transported to the high-speed centrifugal separation device through the delivery pump 12. Preparation 13, after high-speed (8000-12000rpm) centrifugal separation, the dirty alkali liquid is layered: oil, clean alkali liquid, slag (including a small amount of iron and suspended matter), of which the oil is transported to the oil storage tank 14 (entering the solid waste treatment process); the clean alkali liquid passes through the pipeline m and the large-arc elbow of the oil removal return port n, passes through the tank wall on the side away from the lower partition 17, and is transported back to the clean liquid area B of the electrolytic circulation tank 3; the slag is temporarily stored in the slag box through the pipeline q and the pneumatic diaphragm pump to the slag tank 15; after accumulation and sedimentation in the slag tank 15, the supernatant overflows back to the buffer tank 11, and the remaining solid phase gradually accumulates and finally enters the solid waste treatment process.

[0101] After a period of operation, the following effects can be achieved: iron concentration: about 300ppm (originally about 1000-8000ppm); oil concentration: about 450ppm (originally about 1000-30000ppm).

[0102] The present invention can greatly reduce the iron concentration in the cleaning / alkaline solution, which not only improves the cleaning effect of the strip steel surface, but also greatly reduces the probability of iron entering the annealing furnace, greatly improves the furnace condition, and thus prevents the occurrence of nodules, and further ensures the surface quality of the strip steel; greatly reduces the oil concentration in the cleaning / alkaline solution, minimizes the influence of the oil on the cleaning effect, and improves the cleaning effect of the alkaline solution; effectively preserves the functional components in the cleaning / alkaline solution, and improves the performance of the alkaline solution; greatly reduces the discharge of alkaline solution and COD, and reduces the environmental load; greatly reduces the frequent active discharge caused by excessive iron or oil content, and greatly improves the utilization efficiency of the alkaline solution.

[0103] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0104] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in the device claim can also be implemented by one unit or device through software or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.

Claims

1. A special purification system for alkali solution, wherein: The alkali solution purification system includes: A circulation tank (3), wherein the circulation tank (3) is divided into a turbid liquid area (A) and a clear liquid area (B) by a partition; A main line reflux port (b) is arranged at the turbid liquid area (A) near the partition side, the main line reflux port (b) is arranged at the middle and lower part of the turbid liquid area (A), and the main line reflux port (b) is connected with the basket filter (2) and the online tank (1) in sequence through a pipeline; An oil removal suction port (c) is arranged at the middle and lower part of the clear liquid area (B), and the oil removal suction port (c) is connected to the delivery pump (4) and the in-line tank (1) in sequence through a pipeline; An iron removal module, the iron removal module comprising: a rotary drum magnetic filter (7), an iron removal return port (j) and an iron removal suction port (e), wherein the iron removal return port (j) is arranged at the middle and lower part of the clear liquid area (B), the iron removal suction port (e) is arranged at the middle and lower part of the turbid liquid area (A), and the iron removal return port (j) and the iron removal suction port (e) are respectively connected to the rotary drum magnetic filter (7) through pipelines; An oil removal module, the oil removal module comprising: a high-speed centrifugal separation device (13), a floating suction port (8) and an oil removal return port (n), wherein the floating suction port (8) is arranged below the liquid level of the top of the liquid level of the clear liquid area (B), the oil removal return port (n) is arranged below the liquid level of the clear liquid area (B), the floating suction port (8) and the oil removal return port (n) are respectively connected to the high-speed centrifugal separation device (13) through pipelines, The iron removal module further comprises a delivery pump (5), an iron removal outlet (g) and a regulating valve (6), wherein: The iron removal outlet (g) is arranged at the bottom of the turbid liquid area (A); One end of the delivery pump (5) is connected to the iron removal suction port (e) through a pipeline, and the other end of the delivery pump (5) is connected to the iron removal outlet (g) through a pipeline; One end of the regulating valve (6) is connected to a common node of the delivery pump (5) and the iron removal outlet (g), and the other end of the regulating valve (6) is connected to the rotary drum magnetic filter (7).

2. The alkali solution purification system according to claim 1, wherein: The main line reflux port (b) adopts a large-radius elbow, and the large-radius elbow of the main line reflux port (b) is directed to the groove wall direction of the circulation tank (3) on the side away from the lower partition (17) of the turbid liquid area (A), and the outlet forms a horizontal shape and forms an angle of ≤20 with the groove side wall 18 of the circulation tank 3. 0 angle.

3. The alkali solution purification system according to claim 1, wherein: The iron removal return port (j) adopts a large-radius elbow, and the large-radius elbow of the iron removal return port (j) is directed to the lower partition (17) on the side of the clear liquid area B, and forms a ≤20 0 Angle shape.

4. The alkali solution purification system according to claim 1, wherein: The deoiling return port n adopts a large-radius elbow, and the large-radius elbow of the deoiling return port (n) is directed to the groove wall of the circulation tank (3) on the side away from the lower partition (17) of the clear liquid area (B), and forms a groove with an angle of ≤20 with the groove wall side. 0 Angle shape.

5. The alkali solution purification system according to claim 1, wherein: The partition includes a lower partition (17) and an upper partition (16), wherein: The lower baffle (17) is arranged between the turbid liquid area (A) and the clear liquid area (B); the upper baffle (16) is arranged on the upper side of the turbid liquid area (A) close to the lower baffle (17); a gap is provided between the upper baffle (16) and the lower baffle (17); the lower baffle (17) is used to block iron and suspended matter in the turbid liquid area (A) and allow the clear liquid to overflow to the clear liquid area (B); the upper baffle (16) is used to block foam formed on the top of the turbid liquid area (A) in the turbid liquid area (A) so as not to spread to the clear liquid area (B).

6. The alkali solution purification system according to claim 5, wherein: The iron removal suction port (e) is arranged at a diagonal position to the main line reflux port (b), and the delivery pump (5) extracts dirty alkali solution from the turbid liquid area (A) of the circulation tank (3) at a delivery rate of about 1.5 times the processing capacity of the rotary drum magnetic filter (7), wherein 2 / 3 of the flow rate is delivered to the rotary drum magnetic filter (7) for iron separation, and the remaining 1 / 3 of the flow rate is controlled by the regulating valve (6) and refluxed to the turbid liquid area (A) of the circulation tank 3 through the iron removal outlet (g). The iron removal outlet (g) is arranged at a lower part 200 mm away from the iron removal suction port (e) to impact and stir the alkali solution at this position.

7. The alkali solution purification system according to claim 5, wherein: The oil removal module further comprises: a delivery pump (9), a primary filtration system (10), a buffer tank (11), a delivery pump (12), an oil storage tank (14) and a slag tank (15), wherein: One end of the delivery pump (9) is connected to the floating suction port (8) through a pipeline, and the other end of the delivery pump (9) is connected to the primary filtration system (10) through a pipeline; One end of the buffer tank (11) is connected to the primary filtration system (10) through a pipeline, and the other end of the buffer tank (11) is connected to the delivery pump (12) through a pipeline; One end of the high-speed centrifugal separation device (13) is connected to the delivery pump 12 through a pipeline, and the other end of the high-speed centrifugal separation device (13) is connected to the oil removal return port (n) through a pipeline; The oil storage tank (14) is connected to the high-speed centrifugal separation device (13) through a pipeline; The slag tank (15) is connected to the primary filtration system (10) and the high-speed centrifugal separation equipment (13) through pipelines respectively.

8. The alkali solution purification system according to claim 7, wherein: The clean alkali liquid outputted from the high-speed centrifugal separation device (13) is transported back to the clear liquid area (B) on the side of the circulation tank (3) away from the lower partition (17) through the oil removal return port (n), and together with the clean alkali liquid overflowing over the lower partition (17) and the clean alkali liquid filtered by the drum magnetic filter (7), after further precipitation and stable stratification in the clear liquid area (B), the clearer alkali liquid on the upper part will be transported by the delivery pump (4) through the pipeline to the online tank 1 for a new round of flushing / cleaning work; The oil phase output from the high-speed centrifugal separation device (13) is transported to an oil storage tank (14) via a pipeline; The slag phase outputted from the high-speed centrifugal separation device (13) is transported to the slag tank (15) of the oil removal module via a pipeline.

9. The alkali solution purification system according to claim 7, wherein: The oil removal suction port (c) is arranged 100 mm below the lowest limit liquid level of the clear liquid zone (B).

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