A process for treating wastewater from benzohydroxamic acid oximation production

Abstract

The invention relates to a benzohydroxamic acid oximation production wastewater treatment process, which is applied to the technical field related to wastewater treatment. The wastewater is treated by combining extraction and flotation, effectively achieving low emission and a high recovery rate of methyl benzoate, thereby reducing the amount of methyl benzoate used in a reaction process and reducing the difficulty and cost of wastewater treatment. In addition, during the flotation process, a floating bubble releaser is provided. When blockage occurs and affects the release of bubbles, the bubble release outer ring thereon can be automatically controlled to present an undirected floating state, so that the water pressure increased due to the blockage can be biased to a fixed point for centralized blockage clearing. Compared with comprehensive and indiscriminate simultaneous blockage clearing, the required water pressure is relatively small, so that there is no need to wait for a long time for the water pressure to accumulate after the blockage, thereby greatly accelerating the recovery of the floating bubble releaser, thereby effectively ensuring the removal effect and efficiency of organic matter in the wastewater by flotation treatment.

Description

Technical Field

[0001] The present invention relates to a wastewater treatment process, and in particular to a benzohydroxamic acid oximation production wastewater treatment process applied to the technical field related to wastewater treatment. Background Art

[0002] The synthesis of benzohydroxamic acid generally involves reacting methyl benzoate and hydroxylamine under alkaline conditions to produce sodium benzohydroxamic acid salt, which is then acidified with an inorganic acid to produce benzohydroxamic acid. A major challenge in the benzohydroxamic acid production process is the treatment of the chemical wastewater generated by the synthesis. Due to its high water solubility, benzohydroxamic acid is lost in the wastewater at high levels, which not only affects the yield of the target product but also increases the burden on subsequent wastewater treatment. The benzohydroxamic acid feed solution is filtered through a plate and frame filter press to produce the target product, benzohydroxamic acid, and a filtrate. The main organic components in the filtrate are benzohydroxamic acid and benzoic acid, with the benzohydroxamic acid content being less than 1.5% and the benzoic acid content being less than 0.1%. These organic components pose a significant hazard to subsequent water treatment and their content must be reduced to below 50 ppm.

[0003] Based on the above problems, extraction and flotation processes will be introduced to treat wastewater, so as to achieve the effect of low emissions and high yield. However, in the flotation treatment process, the release port of the flotation releaser is easily blocked due to the adhesion of organic matter, the growth of microorganisms, the accumulation of impurities, etc. For wastewater treatment, although flotation has a good impurity removal effect, frequent clearing work will seriously affect the treatment efficiency.

[0004] To solve this problem, the Chinese patent specification with the publication number CN211035313U discloses a dissolved air releaser, which realizes self-clearing of blockages by adding a backwash-related structure, thereby reducing the need to stop flotation and drain the wastewater in the flotation tank to clear the blockage. However, the provision of the backwash-related structure will lead to increased use costs, and the backwash structure is also faced with the problem of blockage due to its location in the flotation tank. Therefore, the Chinese patent specification with the publication number CN218058523U discloses a self-cleaning dissolved air releaser without auxiliary power, which uses the pressure of the water pressure passively increased when blocked to change the distance between the bubble release plates, thereby flushing away the blocked impurities and achieving self-clearing of blockages.

[0005] However, the bubble release plate of this dissolved air releaser moves downward as a whole, that is, the blockage is cleared synchronously as a whole, resulting in a higher pressure required and a longer time required for clearing the blockage, which also poses a certain obstacle to improving the wastewater treatment efficiency. Summary of the Invention

[0006] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that the wastewater generated after the oximation reaction contains a large amount of organic matter, which makes the wastewater treatment more difficult.

[0007] To solve the above problems, the present invention provides a benzohydroxamic acid oximation production wastewater treatment process, comprising the following steps:

[0008] S1, filtering the reaction liquid of the oximation reaction through a plate and frame filter press to obtain a filtrate;

[0009] S2, using methyl benzoate as an extractant and fully mixing and stirring the filtrate to perform extraction, so that the organic matter (benzohydroxamic acid, benzoic acid) is transferred to the organic phase, and the organic phase and wastewater are separated to obtain the loaded ester;

[0010] S3. The extracted wastewater is then passed into a flotation tank for flotation treatment, thereby separating the organic phase (entrained methyl benzoate) in the wastewater. A floating bubble releaser and a laser scattering sensor are provided at the bottom of the flotation tank.

[0011] S31, releasing dissolved air water carrying high-density microbubbles into the flotation tank through a floating bubble releaser;

[0012] S32, detecting bubbles in the flotation tank through a laser scattering sensor and regulating the bubbles to maintain the amount within the expected range;

[0013] S33. When the bubble volume becomes low and it is still difficult to adjust after adjustment, it indicates that the floating bubble releaser may be blocked. The outer ring of the floating bubble releaser is controlled to float in an undirected manner to achieve biased self-cleaning, so that the floating bubble releaser returns to normal and the flotation process is maintained stable.

[0014] S41. After the flotation treatment, the pH of the water is adjusted to neutral and then passed into the multi-effect evaporation system for salt distillation and concentration, thereby recovering industrial salt and achieving low emissions;

[0015] S42, a portion of the organic phase (loaded ester) obtained after flotation and extraction is directly returned to the oximation reaction stage as a raw material, and a portion of the organic phase is purified by a back extraction operation to obtain purified methyl benzoate. This portion of the purified methyl benzoate can be recycled as the extraction agent in step S1, thereby reducing the consumption of new methyl benzoate and achieving 100% recovery;

[0016] The floating bubble releaser includes a fixed bubble sheet, a floating bubble sheet opposite to the fixed bubble sheet, and a plurality of deflection clips respectively installed between the edges of the fixed bubble sheet and the floating bubble sheet, and the deflection clips are slidably connected to the fixed bubble sheet and the floating bubble sheet through an electric slide rail installed on the fixed bubble sheet. The upper end of the fixed bubble sheet is fixedly connected to a water inlet pipe, and a water inlet is opened in the middle of the upper end of the fixed bubble sheet. The water inlet is coaxially arranged with the water inlet pipe. The ends of the fixed bubble sheet and the floating bubble sheet close to each other are also fixedly connected with an upper retaining ring and a lower retaining ring, and both are coaxial with the water inlet.

[0017] In the above-mentioned benzohydroxamic acid oximation production wastewater treatment process, the wastewater is treated by combining extraction and flotation, effectively achieving low emissions and a high recovery rate of methyl benzoate, thereby effectively reducing the difficulty and cost investment of wastewater treatment. Moreover, under the action of the floating bubble releaser, biased self-cleaning can be achieved, which effectively speeds up the unblocking speed and reduces the impact on wastewater treatment efficiency compared to the overall synchronous cleaning in the existing technology.

[0018] As a further improvement of the present application, the sizes of the lower retaining ring and the upper retaining ring are different, and the outer diameter of the upper retaining ring is smaller than the inner diameter of the lower retaining ring, and the ends of the lower retaining ring and the upper retaining ring do not contact the corresponding fixed bubble sheet and floating bubble sheet.

[0019] As a further improvement of the present application, a plurality of fixed and floating ropes are fixedly connected between the fixed bubble sheet and the floating bubble sheet. When the plurality of deflection clips are in a vertical state, the plurality of fixed and floating ropes are in a relaxed state, and the fixed and floating ropes are made of corrosion-resistant non-elastic material.

[0020] As a further improvement of the present application, the deflection clip is E-shaped, and the deflection clip includes two L-shaped clamp arms and a floating section fixedly connected between the two L-shaped clamp arms. The L-shaped clamp arms include two positioning layers fixedly connected to the two L-shaped clamp arms respectively and a floating layer fixedly connected between the two positioning layers. A pressure monitoring unit is provided inside the floating layer, and the spacing between the floating section and the L-shaped clamp arms matches the fixed bubble sheet.

[0021] As a further improvement of the present application, an electromagnetic sheet is fixedly embedded inside the positioning layer, and the two electromagnetic sheets generate magnetic repulsion between each other after being energized. The positioning layer is a hard elastic structure, and the floating layer is a highly elastic structure.

[0022] As a further improvement of the present application, the pressure monitoring unit includes a tension sensor installed at the lower end of the upper positioning layer and a trigger rope fixedly connected between the test end of the tension sensor and the lower positioning layer. The trigger rope is made of elastic material, and when the bias clip is in a vertical and unstressed state, the trigger rope is just in a straightened state.

[0023] As another improvement of the present application, the floating bubble sheet includes a positioning plate, a pre-floating layer fixedly connected to the outer ring of the positioning plate, and multiple bubble outer rings fixedly connected to the outer ring of the pre-floating layer respectively, and multiple limiting rods are connected between the positioning plate and the fixed bubble sheet, the middle parts of the multiple bubble outer rings respectively correspond to multiple deflection clips, the pre-floating layer is an elastic structure, the bubble outer ring is a hard elastic structure, and the connection between the lower retaining ring and the floating bubble sheet is located on the positioning plate.

[0024] As another improved supplement to the present application, a deflection control unit is installed at the bottom of the floating bubble sheet, and the deflection control unit includes an eccentric concave wheel installed at the lower end of the positioning plate through an electric rotating shaft and a plurality of reciprocating hard strips distributed in a circular array attached to the lower end of the positioning plate. A plurality of slide grooves corresponding to the plurality of reciprocating hard strips are opened at the lower end of the positioning plate, and an elastic telescopic rod is installed on the inner wall of the slide groove away from the eccentric concave wheel. The extended end of the elastic telescopic rod faces one side of the eccentric concave wheel and is fixedly connected to a connecting block, and the connecting block is fixedly connected to the reciprocating hard strip.

[0025] As another improved supplement of the present application, one end of the eccentric concave wheel is a cylindrical structure, and the other end of the eccentric concave wheel is an arc-shaped concave structure with an arc transition;

[0026] When the end of the reciprocating hard strip collides with the cylindrical surface of the eccentric concave wheel, the other end of the reciprocating hard strip crosses the pre-floating layer and contacts the lower surface of the bubble-releasing outer ring, and the cross section of the two is not less than 1 / 3 of the radial span of the bubble-releasing outer ring;

[0027] When the end of the reciprocating hard strip contacts the arc surface of the eccentric concave wheel, the other end of the reciprocating hard strip corresponds to the edge of the pre-floating layer close to the eccentric concave wheel.

[0028] In summary, wastewater is treated by combining extraction and flotation, which effectively achieves low emissions and a high recovery rate of methyl benzoate, and can effectively reduce the amount of methyl benzoate used in the oximation reaction, thereby effectively reducing the difficulty and cost of wastewater treatment; in addition, during the flotation process, the setting of the floating bubble releaser can effectively monitor the situation of bubbles in the dissolved water, which is convenient for timely regulation, and when the floating bubble releaser is blocked, it can automatically control the bubble release outer ring on it to present an undirected floating state, so that the increased water pressure due to the blockage can be biased towards the fixed point for concentrated clearing. Compared with the comprehensive and indiscriminate simultaneous clearing of blockages, the required water pressure is relatively small, thereby greatly accelerating the recovery of the floating bubble releaser, thereby effectively ensuring the removal effect and efficiency of organic matter in the wastewater during the flotation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flowchart of the first embodiment of the present application;

[0030] Figure 2 A perspective view of a floating bubble releaser according to a first embodiment of the present application;

[0031] Figure 3 This is an exploded view of a floating bubble releaser according to the first embodiment of the present application;

[0032] Figure 4 A half-section schematic diagram of a floating bubble releaser according to a first embodiment of the present application;

[0033] Figure 5 This is a cross-sectional view of the deflection clip according to the first embodiment of the present application;

[0034] Figure 6 This is a cross-sectional view of the biased clip during biased blockage clearing in the first embodiment of the present application;

[0035] Figure 7 This is a comparison diagram of the changes of the floating bubble releaser before and after biased blockage clearing in the first embodiment of this application;

[0036] Figure 8 This is a three-dimensional diagram of the floating bubble releaser during biased blockage clearing in the first embodiment of the present application;

[0037] Figure 9 This is a front view of the floating bubble releaser during biased blockage clearing in the first embodiment of the present application;

[0038] Figure 10 A top view of a floating bubble-releasing sheet according to a second embodiment of the present application;

[0039] Figure 11 This is a partial schematic diagram of a floating bubble-releasing sheet according to a second embodiment of the present application;

[0040] Figure 12 This is a front view of the floating bubble releaser in the second embodiment of the present application during biased blockage clearing;

[0041] Figure 13 This is a front view of a floating bubble-releasing sheet according to a second embodiment of the present application;

[0042] Figure 14 This is a schematic diagram of the bottom surface of the floating bubble sheet according to the second embodiment of the present application.

[0043] Description of the numbers in the figure:

[0044] 1 fixed bubble sheet, 101 water inlet, 102 lower baffle ring, 103 upper baffle ring, 104 fixed floating rope, 2 floating bubble sheet, 21 positioning plate, 22 pre-floating layer, 23 bubble outer ring, 3 water inlet pipe, 4 deflection clamp, 41 L-shaped clamp arm, 421 positioning layer, 422 floating layer, 401 electromagnetic sheet, 51 tension sensor, 52 trigger rope, 61 eccentric concave wheel, 62 reciprocating hard strip, 63 elastic telescopic rod, 601 connecting block. DETAILED DESCRIPTION

[0045] Two implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0046] The first implementation method:

[0047] Figure 1 A benzohydroxamic acid oximation production wastewater treatment process is shown, comprising the following steps:

[0048] S1, filtering the reaction liquid of the oximation reaction through a plate and frame filter press to obtain a filtrate;

[0049] S2. Using methyl benzoate as an extractant and fully mixing and stirring with the filtrate to perform extraction, so that the organic matter (benzohydroxamic acid, benzoic acid) is transferred to the organic phase, and the organic phase and wastewater are separated;

[0050] S3. The extracted wastewater is then passed into a flotation tank for flotation treatment, thereby separating the organic phase (entrained methyl benzoate) in the wastewater. A floating bubble releaser and a laser scattering sensor are provided at the bottom of the flotation tank.

[0051] S31, releasing dissolved air water carrying high-density microbubbles into the flotation tank through a floating bubble releaser;

[0052] S32, detecting bubbles in the flotation tank through a laser scattering sensor and regulating the bubbles to maintain the amount within the expected range;

[0053] S33. When the bubble volume becomes low and it is still difficult to adjust after adjustment, it indicates that the floating bubble releaser may be blocked. The outer ring of the floating bubble releaser is controlled to float in an undirected manner to achieve biased self-cleaning, so that the floating bubble releaser returns to normal and the flotation process is maintained stable.

[0054] S41. After the flotation treatment, the pH of the water is adjusted to neutral and then passed into the multi-effect evaporation system for salt distillation and concentration, thereby recovering industrial salt and achieving low emissions;

[0055] S42, a portion of the organic phase (loaded ester) obtained after flotation and extraction is directly returned to the oximation reaction stage as a raw material, and a portion of the organic phase is purified by a back extraction operation to obtain purified methyl benzoate. This portion of the purified methyl benzoate can be recycled as the extraction agent in step S1, thereby reducing the consumption of new methyl benzoate and achieving 100% recovery;

[0056] During the entire process described above, organic matter, industrial salt, water, etc. in the wastewater are reasonably reused or recycled, achieving overall low emissions and 100% recycling and reuse of useful substances. Compared with the existing technology, this process not only effectively reduces the difficulty of wastewater treatment, but also improves resource utilization, reduces the consumption of new methyl benzoate, that is, reduces the consumption of reactants, thereby effectively reducing the cost input of benzohydroxamic acid oximation production, and has high practicality and economic value.

[0057] like Figure 2-3 The floating bubble releaser includes a fixed bubble sheet 1, a floating bubble sheet 2 opposite to the fixed bubble sheet 1, and a plurality of deflection clips 4 respectively installed between the edges of the fixed bubble sheet 1 and the floating bubble sheet 2, and the deflection clips 4 are slidably connected to the fixed bubble sheet 1 and the floating bubble sheet 2 through an electric slide rail installed on the fixed bubble sheet 1. The upper end of the fixed bubble sheet 1 is fixedly connected to the water inlet pipe 3, and a water inlet 101 is cut in the middle of the upper end of the fixed bubble sheet 1. The water inlet 101 is coaxially arranged with the water inlet pipe 3. The ends of the fixed bubble sheet 1 and the floating bubble sheet 2 close to each other are also fixedly connected with an upper retaining ring 103 and a lower retaining ring 102, and both are coaxial with the water inlet 101. Figure 4 The lower retaining ring 102 and the upper retaining ring 103 have different sizes, and the outer diameter of the upper retaining ring 103 is smaller than the inner diameter of the lower retaining ring 102. The ends of the lower retaining ring 102 and the upper retaining ring 103 do not contact the corresponding fixed bubble sheet 1 and the floating bubble sheet 2. The lower retaining ring 102 and the upper retaining ring 103 can make the dissolved air water entering between the fixed bubble sheet 1 and the floating bubble sheet 2 obtain a certain pressure-holding effect, which is convenient for better release of bubbles and makes the adhering organic matter float better. When in use, the dissolved air water enters between the fixed bubble sheet 1 and the floating bubble sheet 2 along the water inlet pipe 3 and the water inlet 101, is pressurized between the two, and then crosses the gap between the lower retaining ring 102 and the upper retaining ring 103 to enter the outer layer of the fixed bubble sheet 1 and the floating bubble sheet 2, and then releases the dissolved air water into the flotation tank to provide microbubbles.

[0058] like Figure 4 A plurality of fixed and floating ropes 104 are fixedly connected between the fixed bubble sheet 1 and the floating bubble sheet 2. When the plurality of deflection clips 4 are in a vertical state, the plurality of fixed and floating ropes 104 are in a relaxed state, and the fixed and floating ropes 104 are made of corrosion-resistant non-elastic material. The fixed and floating ropes 104 are mainly used for limiting the position, so that when the floating bubble sheet 2 moves downward under the action of water pressure, the gap between the fixed bubble sheet 1 and the floating bubble sheet 2 is not easy to be too large, thereby effectively maintaining the stability between the fixed bubble sheet 1 and the floating bubble sheet 2, so that the floating bubble sheet 2 is not easy to accidentally separate from the fixed bubble sheet 1.

[0059] like Figure 5The deflection clip 4 is E-shaped, and the deflection clip 4 includes two L-shaped clamping arms 41 and a floating section fixedly connected between the two L-shaped clamping arms 41. The L-shaped clamping arm 41 includes two positioning layers 421 respectively fixedly connected to the two L-shaped clamping arms 41 and a floating layer 422 fixedly connected between the two positioning layers 421. A pressure monitoring unit is arranged inside the floating layer 422. The interval between the floating section and the L-shaped clamping arm 41 matches the fixed bubble sheet 1. The gaps formed between the upper and lower L-shaped clamping arms 41 and the floating section of the deflection clip 4 are just clamped on the corresponding fixed bubble sheet 1 or floating bubble sheet 2, thereby limiting the floating bubble sheet 2 below, so that the floating bubble sheet 2 is not easily separated from the fixed bubble sheet 1 under the squeeze of water pressure when releasing dissolved air and water.

[0060] The positioning layer 421 is fixedly embedded with an electromagnetic sheet 401. When energized, the two electromagnetic sheets 401 generate a magnetic repulsion between them. The positioning layer 421 is a rigid elastic structure, while the floating layer 422 is a highly elastic structure. When energized, the two electromagnetic sheets 401 repel each other, pushing the fixed and floating bubble sheets 1 and 2 longitudinally, enhancing the connection stability between them and the corresponding L-shaped clamping arms 41. This setting is optional and can be selected based on actual needs during implementation.

[0061] The pressure monitoring unit includes a tension sensor 51 installed at the lower end of the upper positioning layer 421 and a trigger rope 52 fixedly connected between the test end of the tension sensor 51 and the lower positioning layer 421. The trigger rope 52 is made of elastic material, and when the deflection clip 4 is in a vertical and unstressed state, the trigger rope 52 is just in a straight state. When a blockage occurs, less dissolved air and water flow through the blocked area. At this time, the corresponding deflection clip 4 is subjected to a relatively small force, while the unblocked area is subjected to a relatively large force due to the water pressure. Figure 6 At this time, the corresponding floating layer 422 will be deformed toward the side away from the water inlet pipe 3, which will cause the trigger rope 52 to be pulled, causing the data of the tension sensor 51 to change. When the amplitude of the data change on the tension sensor 51 is too large or too small, it indicates that the floating bubble releaser is blocked. Figure 7-8 , multiple deflection clips 4 can be controlled to gather toward the side where the data of the tension sensor 51 becomes larger, and their distribution range is controlled not to exceed 120°, so that the clamping force of the fixed bubble sheet 1 and the floating bubble sheet 2 is biased, that is, the two are in an unbalanced state, such as Figure 9At this time, under the action of water pressure, the floating bubble release sheet 2 will be tilted downward away from one side of the multiple deflection clips 4, causing the distance between the fixed bubble release sheet 1 and the floating bubble release sheet 2 to change unevenly, causing one side to expand. At this time, under the action of the increased water pressure due to blockage, the impurities deposited at the place where the spacing is significantly increased can be effectively washed away, and then according to the data on the multiple tension sensors 51, the gathering positions of the multiple deflection clips 4 are changed multiple times, and the above process is repeated to achieve deflected self-cleaning. Compared with the method of moving the floating bubble release sheet 2 downward as a whole to expand the gap to clear the blockage in the prior art, the required water pressure is relatively small, the impurities are less difficult to be washed away, and the speed is faster, so that the blocked floating bubble releaser can return to normal faster to maintain the stability of the flotation process, thereby effectively ensuring the efficiency of wastewater treatment.

[0062] In the above-mentioned benzohydroxamic acid oximation production wastewater treatment process, the wastewater is treated by combining extraction and flotation, effectively achieving low emissions and a high recovery rate of methyl benzoate, thereby effectively reducing the difficulty and cost investment of wastewater treatment. Moreover, under the action of the floating bubble releaser, biased self-cleaning can be achieved, which effectively speeds up the unblocking speed and reduces the impact on wastewater treatment efficiency compared to the overall synchronous cleaning in the existing technology.

[0063] The second implementation method:

[0064] This embodiment further improves the floating bubble-releasing sheet 2 on the basis of the first embodiment, and the rest of the parts remain the same as the first embodiment.

[0065] Figure 10 As shown, the floating bubble sheet 2 includes a positioning plate 21, a pre-floating layer 22 fixedly connected to the outer ring of the positioning plate 21, and a plurality of bubble outer rings 23 respectively fixedly connected to the outer rings of the pre-floating layer 22, and a plurality of limiting rods are connected between the positioning plate 21 and the fixed bubble sheet 1, and the middle parts of the plurality of bubble outer rings 23 respectively correspond to the plurality of deflection clips 4, the pre-floating layer 22 is an elastic structure, the bubble outer rings 23 are a hard elastic structure, and the connection between the lower retaining ring 102 and the floating bubble sheet 2 is located on the positioning plate 21. By setting the pre-floating layer 22 and the bubble outer rings 23, the outer ring of the floating bubble sheet 2 can be subdivided, as shown in FIG. Figure 12 , so that each bubble-releasing outer ring 23 can be tilted and deformed downward, thereby changing the interval between it and the fixed bubble-releasing sheet 1, so as to achieve targeted local variable gap unblocking. Compared with the first embodiment, it is more targeted, has a better unblocking effect on the floating bubble releaser, is faster, and can achieve unblocking when the pressure is relatively small.

[0066] like Figure 13-14A deflection control unit is installed at the bottom of the floating bubble sheet 2, and the deflection control unit includes an eccentric concave wheel 61 installed at the lower end of the positioning plate 21 through an electric rotating shaft and a plurality of reciprocating hard strips 62 distributed in a ring array attached to the lower end of the positioning plate 21. A plurality of slide grooves corresponding to the plurality of reciprocating hard strips 62 are opened at the lower end of the positioning plate 21. An elastic telescopic rod 63 is installed on the inner wall of the slide away from the eccentric concave wheel 61. The extended end of the elastic telescopic rod 63 faces one side of the eccentric concave wheel 61 and is fixedly connected to a connecting block 601. The connecting block 601 is fixedly connected to the reciprocating hard strip 62.

[0067] One end of the eccentric concave wheel 61 is a cylindrical structure, and the other end of the eccentric concave wheel 61 is an arc-shaped concave structure with an arc transition; when the end of the reciprocating hard strip 62 conflicts with the cylindrical surface of the eccentric concave wheel 61, the other end of the reciprocating hard strip 62 crosses the pre-floating layer 22 and contacts the lower surface of the bubble-releasing outer ring 23, and the cross-section of the two is not less than 1 / 3 of the radial span of the bubble-releasing outer ring 23; when the end of the reciprocating hard strip 62 conflicts with the concave arc surface of the eccentric concave wheel 61, the other end of the reciprocating hard strip 62 corresponds to the edge of the pre-floating layer 22 close to the eccentric concave wheel 61.

[0068] During the process of releasing bubbles, the eccentric concave wheel 61 can be controlled to rotate by the electric rotating shaft, so that the contact points of the multiple reciprocating hard strips 62 and the eccentric concave wheel 61 show periodic changes, and the contact points continuously change between the cylindrical surface and the concave arc surface, thereby driving the bubble-releasing outer ring 23 to continuously reciprocate and translate along the lower surface of the floating bubble-releasing sheet 2. When it contacts the cylindrical surface, it can support the corresponding bubble-releasing outer ring 23 to make it horizontal. When it contacts the concave arc surface, the bubble-releasing outer ring 23 is reset. At this time, the pre-floating layer 22 is not restricted, so that the corresponding bubble-releasing outer ring 23 tilts downward, thereby causing the multiple bubble-releasing outer rings 23 to sequentially show a process of downward movement-horizontal movement-downward movement. Compared with the prior art, the outer ring of the floating bubble-releasing sheet 2 is continuously floating. On the one hand, the gap can be continuously changed, so that impurities are less likely to adhere excessively during the release of dissolved air and water, which can greatly reduce the probability of blockage. On the other hand, its dynamic state also makes it easier for some deposited impurities to be washed away when tilted, thereby extending the probability of two blockages.

[0069] In addition, it is worth noting that in this embodiment, when the blockage is more serious and difficult to clear, multiple deflection clips 4 can also be controlled to gather toward one side of the cylindrical surface of the eccentric concave wheel 61. At this time, multiple bubble-releasing outer rings 23 that have been released from the restrictions can be tilted downward to a relatively larger extent, so that the gap between the bubble-releasing outer ring 23 and the fixed bubble-releasing sheet 1 changes more widely, accelerating the clearing of the blockage, so that the flotation process is not easily affected too much, and the efficiency of wastewater treatment is guaranteed.

[0070] In summary, wastewater is treated by combining extraction and flotation, which effectively achieves low emissions and a high recovery rate of methyl benzoate, and can effectively reduce the amount of methyl benzoate used in the oximation reaction, thereby effectively reducing the difficulty and cost of wastewater treatment; in addition, during the flotation process, the setting of the floating bubble releaser can effectively monitor the situation of bubbles in the dissolved water, which is convenient for timely regulation, and when the floating bubble releaser is blocked, it can automatically control the bubble release outer ring on it to present an undirected floating state, so that the increased water pressure due to the blockage can be biased towards the fixed point for concentrated clearing. Compared with the comprehensive and indiscriminate simultaneous clearing of blockages, the required water pressure is relatively small, thereby greatly accelerating the recovery of the floating bubble releaser, thereby effectively ensuring the removal effect and efficiency of organic matter in the wastewater during the flotation process.

[0071] In view of current actual needs, the protection scope of the above-mentioned implementation mode adopted in this application is not limited to this. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. A process for treating wastewater from the oximation of benzohydroxamic acid, characterized in that: The following steps are involved: S1, filtering the reaction liquid of the oximation reaction through a plate and frame filter press to obtain a filtrate; S2, using methyl benzoate as an extractant and fully mixing and stirring the filtrate to perform extraction, so that the organic substances benzohydroxamic acid and benzoic acid are transferred to the organic phase, and then the organic phase and the wastewater are separated to obtain the loaded ester; S3, passing the extracted wastewater into a flotation tank for flotation treatment, thereby separating the organic phase entrained in the wastewater, wherein the organic phase is the entrained methyl benzoate, and a floating bubble releaser and a laser scattering sensor are provided at the bottom of the flotation tank; S31, releasing dissolved air water carrying high-density microbubbles into the flotation tank through a floating bubble releaser, and the bubbles capture organic particles adhering to the wastewater and float them together, thus achieving flotation; S32, detecting bubbles in the flotation tank through a laser scattering sensor and regulating the bubbles to maintain the amount within the expected range; S33. When the bubble volume becomes low and it is still difficult to adjust after adjustment, it indicates that the floating bubble releaser may be blocked. The outer ring of the floating bubble releaser is controlled to float in an undirected manner to achieve biased self-cleaning, so that the floating bubble releaser returns to normal and the flotation process is maintained stable. S41. After the flotation treatment, the pH of the water is adjusted to neutral and then passed into the multi-effect evaporation system for salt distillation and concentration, thereby recovering industrial salt and achieving low emissions; S42, the organic phase obtained after flotation and extraction is directly returned to the oximation reaction stage as a raw material, and the organic phase is purified by a back extraction operation to obtain purified methyl benzoate, which can be recycled as the extraction agent in step S1, thereby reducing the consumption of new methyl benzoate and achieving 100% recovery; The floating bubble releaser comprises a fixed bubble sheet (1), a floating bubble sheet (2) facing the fixed bubble sheet (1), and a plurality of deflection clips (4) respectively installed between the edges of the fixed bubble sheet (1) and the floating bubble sheet (2), and the deflection clips (4) are slidably connected to the fixed bubble sheet (1) and the floating bubble sheet (2) via an electric slide rail installed on the fixed bubble sheet (1). The upper end of the fixed bubble sheet (1) is fixedly connected to a water inlet pipe (3), and a water inlet (101) is cut in the middle of the upper end of the fixed bubble sheet (1). The water inlet (101) is coaxially arranged with the water inlet pipe (3). The ends of the fixed bubble sheet (1) and the floating bubble sheet (2) close to each other are also fixedly connected to an upper retaining ring (103) and a lower retaining ring (102), and both are coaxial with the water inlet (101).

2. The process for treating wastewater from benzohydroxamic acid oximation according to claim 1, wherein: The lower retaining ring (102) and the upper retaining ring (103) have different sizes, and the outer diameter of the upper retaining ring (103) is smaller than the inner diameter of the lower retaining ring (102). The ends of the lower retaining ring (102) and the upper retaining ring (103) do not contact the corresponding fixed bubble sheet (1) and floating bubble sheet (2).

3. The process for treating wastewater from benzohydroxamic acid oximation according to claim 2, wherein: A plurality of fixed and floating ropes (104) are fixedly connected between the fixed and floating bubble sheets (1) and the floating and floating bubble sheets (2). When the plurality of deflection clips (4) are in a vertical state, the plurality of fixed and floating ropes (104) are in a relaxed state, and the fixed and floating ropes (104) are made of a corrosion-resistant non-elastic material.

4. The process for treating wastewater from benzohydroxamic acid oximation according to claim 1, wherein: The deflection clip (4) is E-shaped, comprising two L-shaped clip arms (41) and a floating section fixedly connected between the two L-shaped clip arms (41), the L-shaped clip arms (41) comprising two positioning layers (421) respectively fixedly connected to the two L-shaped clip arms (41) and a floating layer (422) fixedly connected between the two positioning layers (421), a pressure monitoring unit being provided inside the floating layer (422), and a spacing between the floating section and the L-shaped clip arms (41) matching the fixed bubble sheet (1).

5. The process for treating wastewater from benzohydroxamic acid oximation according to claim 4, wherein: An electromagnetic sheet (401) is fixedly embedded in the positioning layer (421), and the two electromagnetic sheets (401) generate a magnetic repulsion force between each other after being energized. The positioning layer (421) is a hard elastic structure, and the floating layer (422) is a highly elastic structure.

6. The process for treating wastewater from benzohydroxamic acid oximation production according to claim 5, wherein: The pressure monitoring unit comprises a tension sensor (51) installed at the lower end of the upper positioning layer (421) and a trigger rope (52) fixedly connected between the test end of the tension sensor (51) and the lower positioning layer (421). The trigger rope (52) is made of elastic material, and when the deflection clip (4) is in a vertical and unstressed state, the trigger rope (52) is just in a straightened state.

7. The process for treating wastewater from benzohydroxamic acid oximation production according to claim 6, wherein: The floating bubble-releasing sheet (2) comprises a positioning plate (21), a pre-floating layer (22) fixedly connected to the outer ring of the positioning plate (21), and a plurality of bubble-releasing outer rings (23) respectively fixedly connected to the outer rings of the pre-floating layer (22), and a plurality of limiting rods are connected between the positioning plate (21) and the fixed bubble-releasing sheet (1), the middle portions of the plurality of bubble-releasing outer rings (23) respectively correspond to a plurality of deflection clips (4), the pre-floating layer (22) is an elastic structure, the bubble-releasing outer rings (23) are a hard elastic structure, and the connection between the lower retaining ring (102) and the floating bubble-releasing sheet (2) is located on the positioning plate (21).

8. The process for treating wastewater from benzohydroxamic acid oximation production according to claim 7, wherein: A deflection control unit is installed at the bottom of the floating bubble release sheet (2), and the deflection control unit includes an eccentric concave wheel (61) installed on the lower end of the positioning plate (21) through an electric rotating shaft and a plurality of reciprocating hard strips (62) attached to the lower end of the positioning plate (21) and distributed in a ring array. The lower end of the positioning plate (21) is cut with a plurality of sliding grooves corresponding to the plurality of reciprocating hard strips (62), and an elastic telescopic rod (63) is installed on the inner wall of the sliding groove away from the eccentric concave wheel (61). The extended end of the elastic telescopic rod (63) faces one side of the eccentric concave wheel (61) and is fixedly connected to a connecting block (601). The connecting block (601) is fixedly connected to the reciprocating hard strip (62).

9. The process for treating wastewater from benzohydroxamic acid oximation production according to claim 8, wherein: One end of the eccentric concave wheel (61) is a cylindrical structure, and the other end of the eccentric concave wheel (61) is an arc-shaped concave structure with an arc transition; When the end of the reciprocating hard strip (62) contacts the cylindrical surface of the eccentric concave wheel (61), the other end of the reciprocating hard strip (62) crosses the pre-floating layer (22) and contacts the lower surface of the bubble-releasing outer ring (23), and the cross section of the two is not less than 1 / 3 of the radial span of the bubble-releasing outer ring (23); When the end of the reciprocating hard strip (62) contacts the concave arc surface of the eccentric concave wheel (61), the other end of the reciprocating hard strip (62) corresponds to the edge of the pre-floating layer (22) on the side close to the eccentric concave wheel (61).

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