Benzohydroxamic acid oximation production wastewater treatment process

Abstract

The invention relates to a benzohydroxamic acid oximation production wastewater treatment process which is applied to the related technical field of wastewater treatment, wastewater is treated in a manner of combining extraction and air floatation, and low emission and high recovery rate of methyl benzoate are effectively realized, so that the use amount of methyl benzoate in the reaction process is reduced, and the production cost is reduced. The wastewater treatment difficulty and the cost investment are reduced; in addition, in the air floatation process, through the arrangement of the floating type bubble releaser, when blockage affects throwing of the bubble amount, the bubble releasing outer ring on the floating type bubble releaser can be automatically controlled to be in a non-directional floating state, water pressure increased due to blockage can deviate to a fixed point for centralized blockage removal, compared with comprehensive undifferentiated synchronous blockage removal, the needed water pressure is relatively small, and the blockage removal efficiency is improved. Therefore, long-time waiting for water pressure accumulation is not needed after blockage, the recovery of the floating type bubble releaser is greatly accelerated, and the removal effect and efficiency of air floatation treatment on organic matters in wastewater are effectively guaranteed.

Description

Technical Field

[0001] A wastewater treatment process involved in the present invention, particularly a wastewater treatment process for benzohydroxamic acid oximation production wastewater applied to the related technical field of wastewater treatment. Background Art

[0002] The synthesis process of benzohydroxamic acid generally produces sodium benzohydroxamate by reacting methyl benzoate with hydroxylamine under alkaline conditions, and then benzohydroxamic acid is obtained by acidifying with inorganic acid; the main problem existing in the benzohydroxamic acid production process is the treatment of chemical wastewater generated during synthesis. Due to the good water solubility of benzohydroxamic acid, it has a large loss in wastewater, which on the one hand affects the yield of the target product, and on the other hand increases the load of subsequent wastewater treatment. The benzohydroxamic acid feed liquid in production is filtered by a plate and frame filter press to obtain the target product benzohydroxamic acid and filtrate. The main organic components in the filtrate are benzohydroxamic acid and benzoic acid, among which the content of benzohydroxamic acid is less than 1.5% and the content of benzoic acid is less than 0.1%. These organic components are important hazards affecting subsequent water treatment and need to reduce their content to below 50 ppm.

[0003] Based on the above problems, extraction and air flotation processes will be introduced for wastewater treatment to achieve the effects of low emissions and high yields. However, in the air flotation treatment process, the release ports of the air flotation release device are easily blocked due to the attachment of organic substances, the growth of microorganisms, the accumulation of impurities, etc. For wastewater treatment, although the impurity removal effect of air flotation is very good, the frequent clogging cleaning 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 release device, which realizes self-unblocking by adding relevant backwashing structures to reduce the situation of stopping air flotation and draining the wastewater in the air flotation tank for unblocking. However, the setting of the backwashing relevant structures will lead to an increase in use costs, and the backwashing structure also faces the problem of being blocked since it is also located in the air flotation tank. Therefore, the Chinese patent specification with the publication number CN218058523U discloses a self-cleaning dissolved air release device without auxiliary power, which uses the pressure increased passively by the water pressure during clogging to change the distance between the bubble release plates, thereby washing away the blocked impurities and realizing self-unblocking.

[0005] However, the overall downward movement of the bubble release plates of this dissolved air release device, that is, synchronous unblocking of the whole, results in a relatively large required pressure and a long unblocking time, which also poses a certain obstacle to the improvement of wastewater treatment efficiency. Summary of the Invention

[0006] Aiming at 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 more organic substances, resulting in greater difficulty in wastewater treatment.

[0007] To solve the above problems, the present invention provides a treatment process for the wastewater produced in the oximation of benzohydroxamic acid, which includes the following steps: S1. Filter the reaction solution of the oximation reaction through a plate and frame filter press to obtain a filtrate; S2. Use methyl benzoate as an extractant to fully mix and stir with the filtrate for extraction, so that the organic substances (benzohydroxamic acid, benzoic acid) are transferred to the organic phase, separate the organic phase from the wastewater, and obtain a loaded ester; S3. Pass the extracted wastewater into a flotation tank for flotation treatment to separate the organic phase (entrained methyl benzoate) entrained in the wastewater. A floating bubble release device and a laser scattering sensor are arranged at the bottom of the flotation tank; S31. Release the dissolved air water carrying microbubbles with high density into the flotation tank through the floating bubble release device; S32. Detect the bubble condition in the flotation tank through the laser scattering sensor and adjust it to maintain the bubble volume within the expected range; S33. When the bubble volume becomes low and it is still difficult to callback after adjustment, it indicates that the floating bubble release device may be blocked. Control the outer ring of the bubble release of the floating bubble release device to present an indefinite floating state to achieve biased self-cleaning, so that the floating bubble release device returns to normal and maintains the stable progress of the flotation process; S41. After adjusting the pH of the water after flotation treatment to neutral, it can be passed into a multi-effect evaporation system for salt evaporation and concentration to recover industrial salt, thereby achieving low emissions; S42. Part of the organic phase (loaded ester) obtained after flotation and extraction is directly returned to the oximation reaction stage as a raw material, and part of the organic phase is purified through back-extraction operation to obtain purified methyl benzoate. This part of the purified methyl benzoate can be used as the extractant in step S1 for recycling, thereby reducing the consumption of new methyl benzoate and achieving 100% recovery; The floating bubble release device includes a fixed bubble release plate, a floating bubble release plate opposite to the fixed bubble release plate, and a plurality of biasing clips respectively installed between the edges of the fixed bubble release plate and the floating bubble release plate. The biasing clips are slidably connected to the fixed bubble release plate and the floating bubble release plate through an electric slide rail installed on the fixed bubble release plate. The upper end of the fixed bubble release plate is fixedly connected with a water inlet pipe. A water inlet is drilled in the middle of the upper end of the fixed bubble release plate, and the water inlet is coaxially arranged with the water inlet pipe. Upper retaining rings and lower retaining rings are respectively fixedly connected to the ends of the fixed bubble release plate and the floating bubble release plate close to each other, and both are coaxially arranged with the water inlet.

[0008] In the above-mentioned treatment process for the wastewater produced in the oximation of benzohydroxamic acid, the wastewater is treated by combining extraction and air flotation, effectively achieving low emissions and a high recovery rate of methyl benzoate. Furthermore, it effectively reduces the difficulty and cost input of wastewater treatment. And under the action of the floating bubble release device, it can achieve partial self-cleaning. Compared with the overall synchronous cleaning in the prior art, it effectively speeds up the blockage removal speed and reduces the impact on the wastewater treatment efficiency.

[0009] As a further improvement of this 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. The ends of the lower retaining ring and the upper retaining ring do not contact the corresponding fixed bubble releasing sheet and floating bubble releasing sheet.

[0010] As a further improvement of this application, a plurality of fixed floating ropes are fixedly connected between the fixed bubble releasing sheet and the floating bubble releasing sheet. When all the plurality of biasing clip pieces are in the vertical state, all the fixed floating ropes are in a relaxed state, and the fixed floating ropes are made of corrosion-resistant non-elastic materials.

[0011] As a further improvement of this application, the biasing clip piece is in an E shape. The biasing clip piece includes two L-shaped clip arms and a floating section fixedly connected between the two L-shaped clip arms. The L-shaped clip arm includes two positioning layers respectively fixedly connected to the two L-shaped clip arms and a floating layer fixedly connected between the two positioning layers. A pressure monitoring unit is arranged inside the floating layer. The interval between the floating section and the L-shaped clip arm matches the fixed bubble releasing sheet.

[0012] As a further improvement of this application, electromagnetic sheets are fixedly inlaid inside the positioning layers. After the two electromagnetic sheets are energized, magnetic repulsion is generated between them. The positioning layer is a rigid elastic structure, and the floating layer is a highly elastic structure.

[0013] As a further improvement of this 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 an elastic material, and when the biasing clip piece is in the vertical and unloaded state, the trigger rope is just in a straightened state.

[0014] As another improvement of this application, the floating bubble releasing sheet includes a positioning plate, a pre-floating layer fixedly connected to the outer circle of the positioning plate, and a plurality of bubble releasing outer rings respectively fixedly connected to the outer circle of the pre-floating layer. And a plurality of limiting rods are connected between the positioning plate and the fixed bubble releasing sheet. The middle parts of the plurality of bubble releasing outer rings correspond to the plurality of biasing clip pieces respectively. The pre-floating layer is an elastic structure, and the bubble releasing outer ring is a rigid elastic structure. And the connection part between the lower retaining ring and the floating bubble releasing sheet is located on the positioning plate.

[0015] As another improvement and supplement to the present application, a control unit is installed at the bottom of the floating bubble release sheet, and the 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 and 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.

[0016] As another improvement 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; When the end of the reciprocating hard strip contacts 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; 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.

[0017] In summary, wastewater is treated by combining extraction and flotation, which can effectively achieve low emissions and 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, through the setting of a floating bubble releaser, the situation of bubbles in the dissolved water can be effectively monitored, which is convenient for timely regulation, and after the floating bubble releaser is blocked, the outer ring of the bubble release can be automatically controlled to present a non-directional floating state, so that the increased water pressure caused by the blockage can be biased towards the fixed point for concentrated clearing. Compared with comprehensive and indiscriminate simultaneous clearing, 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

[0018] Figure 1 This is a flowchart of the first implementation method of this application; Figure 2 A three-dimensional diagram of a floating bubble releaser according to a first embodiment of the present application; Figure 3 An exploded view of a floating bubble releaser according to a first embodiment of the present application; Figure 4 A half-section schematic diagram of a floating bubble releaser according to a first embodiment of the present application; Figure 5 A cross-sectional view of a deflection clip according to a first embodiment of the present application; Figure 6 This is a cross-sectional view of the biased clip during biased blockage clearing in the first embodiment of the present application; Figure 7 This is a comparison chart of the changes in the floating bubble release device before and after deviation and blockage clearing for the first implementation mode of this application; Figure 8 This is a three-dimensional view of the floating bubble release device during deviation and blockage clearing for the first implementation mode of this application; Figure 9 This is a front view of the floating bubble release device during deviation and blockage clearing for the first implementation mode of this application; Figure 10 This is a top view of the floating bubble releasing sheet for the second implementation mode of this application; Figure 11 This is a partial schematic diagram of the floating bubble releasing sheet for the second implementation mode of this application; Figure 12 This is a front view of the floating bubble release device during deviation and blockage clearing for the second implementation mode of this application; Figure 13 This is a front view of the floating bubble releasing sheet for the second implementation mode of this application; Figure 14 This is a schematic diagram of the bottom surface of the floating bubble releasing sheet for the second implementation mode of this application.

[0019] Explanation of reference numerals in the figure: 1 fixed bubble releasing sheet, 101 water inlet, 102 lower retaining ring, 103 upper retaining ring, 104 fixed floating rope, 2 floating bubble releasing sheet, 21 positioning plate, 22 pre-floating layer, 23 bubble releasing outer ring, 3 water inlet pipe, 4 deviation clip, 41 L-shaped clip arm, 421 positioning layer, 422 floating layer, 401 electromagnetic sheet, 51 tension sensor, 52 trigger rope, 61 eccentric cam, 62 reciprocating hard bar, 63 elastic telescopic rod, 601 connecting block. Specific implementation mode

[0020] The following will make a detailed description of the two implementation modes of this application with reference to the accompanying drawings.

[0021] The first implementation mode: Figure 1 It is shown that a process for treating the production wastewater of benzohydroxamic acid oximation includes the following steps: S1. Filter the reaction liquid of the oximation reaction through a plate and frame filter press to obtain a filtrate; S2. Use methyl benzoate as an extractant to fully mix and stir with the filtrate for extraction, so that the organic substances (benzohydroxamic acid, benzoic acid) are transferred to the organic phase, and the organic phase and the wastewater are separated; S3. Then introduce the extracted wastewater into a flotation tank for flotation treatment, so as to separate the organic phase (entrained methyl benzoate) entrained in the wastewater. A floating bubble release device and a laser scattering sensor are arranged at the bottom of the flotation tank; S31. Release the dissolved air water carrying high-density microbubbles into the air flotation tank through a floating bubble release device; S32. Detect the bubble condition in the air flotation tank through a laser scattering sensor, and adjust it to maintain the bubble volume within the expected range; S33. When the bubble volume becomes low and it is still difficult to callback after adjustment, it indicates that the floating bubble release device may be blocked. Control the bubble release outer ring of the floating bubble release device to present an undirectional floating state, realize biased self-cleaning, make the floating bubble release device return to normal, and maintain the stable progress of the air flotation process; S41. After the water treated by air flotation is adjusted to neutral pH, it can be introduced into a multi-effect evaporation system for salt evaporation and concentration, so as to recover industrial salt and then achieve low emissions; S42. Part of the organic phase (loaded ester) obtained after air flotation and extraction is directly returned to the oximation reaction stage as raw material. Part of the organic phase is purified through back-extraction operation to obtain purified methyl benzoate. This part of the purified methyl benzoate can be used as the extractant in step S1 for recycling, thereby reducing the consumption of new methyl benzoate, and at the same time achieving 100% recovery; In the above entire process, organic matters, industrial salts, water, etc. in the wastewater are all reasonably reused or recycled again. Overall, low emissions and 100% recycling and reuse of useful substances are achieved. Compared with the prior art, it not only effectively reduces the difficulty of wastewater treatment, but also improves the utilization rate of resources, 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 practicability and economic value.

[0022] Such as Figures 2 - 3 , the floating bubble release device includes a fixed bubble release sheet 1, a floating bubble release sheet 2 opposite to the fixed bubble release sheet 1, and a plurality of biasing clips 4 respectively installed between the edges of the fixed bubble release sheet 1 and the floating bubble release sheet 2. And the biasing clips 4 are slidably connected to the fixed bubble release sheet 1 and the floating bubble release sheet 2 through an electric slide rail installed on the fixed bubble release sheet 1. The upper end of the fixed bubble release sheet 1 is fixedly connected with a water inlet pipe 3. A water inlet 101 is drilled in the middle of the upper end of the fixed bubble release sheet 1. The water inlet 101 is coaxially arranged with the water inlet pipe 3. The mutually close ends of the fixed bubble release sheet 1 and the floating bubble release sheet 2 are respectively fixedly connected with an upper retaining ring 103 and a lower retaining ring 102, and both of them are coaxially arranged with the water inlet 101. Such as Figure 4The sizes of the lower baffle ring 102 and the upper baffle ring 103 are different, and the outer diameter of the upper baffle ring 103 is smaller than the inner diameter of the lower baffle ring 102. The ends of the lower baffle ring 102 and the upper baffle ring 103 do not contact the corresponding fixed bubble sheet 1 and the floating bubble sheet 2. The lower baffle ring 102 and the upper baffle 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 effect of floating of adhered organic matter 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 pressed between the two, and then climbs over the gap between the lower baffle ring 102 and the upper baffle 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.

[0023] like Figure 4 A plurality of fixing 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 fixing and floating ropes 104 are in a relaxed state, and the fixing and floating ropes 104 are made of corrosion-resistant non-elastic material. The fixing 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 interval between the floating bubble sheet 2 and the fixed bubble sheet 1 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.

[0024] like Figure 5 The deflection clip 4 is E-shaped, and the deflection clip 4 includes two L-shaped clamp arms 41 and a floating section fixedly connected between the two L-shaped clamp arms 41. The L-shaped clamp arm 41 includes two positioning layers 421 respectively fixedly connected to the two L-shaped clamp 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 clamp arm 41 matches the fixed bubble sheet 1. The gaps formed between the upper and lower L-shaped clamp 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 squeezing of water pressure when releasing dissolved air water.

[0025] The positioning layer 421 is fixedly embedded with an electromagnetic sheet 401. The two electromagnetic sheets 401 generate magnetic repulsion 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. When the two electromagnetic sheets 401 are energized, the two repel each other, thereby pushing the fixed bubble sheet 1 and the floating bubble sheet 2 in the longitudinal direction, so that the connection stability between the two and the corresponding L-shaped clamp arm 41 is higher. Among them, this setting is optional, and it can be selected according to actual needs during specific implementation.

[0026] 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 an elastic material, and when the deflecting clip 4 is in a vertical and unloaded state, the trigger rope 52 is just in a straightened state. When a blockage occurs, less dissolved air water flows through the blocked area. At this time, the force on the corresponding deflecting clip 4 is relatively small, while at the unblocked area, due to the water pressure, the force is relatively large. As Figure 6 , this will cause the corresponding floating layer 422 to deform towards the side away from the water inlet pipe 3, and then cause the trigger rope 52 to be pulled, causing a change in the data of the tension sensor 51. When the amplitude of the data change on the tension sensor 51 is too large or too small, it indicates that there is a blockage phenomenon in this floating bubble release device. At this time, as Figures 7 - 8 , multiple deflecting clips 4 can be controlled to first gather towards the side where the data of the tension sensor 51 increases, and the controlled distribution range does not exceed 120°, so that there is a bias in the clamping force between the fixed bubble release sheet 1 and the floating bubble release sheet 2, that is, the two are in an unbalanced state. As Figure 9 , at this time, under the action of the water pressure, the side of the floating bubble release sheet 2 away from the multiple deflecting clips 4 will tilt downward, causing the distance between the fixed bubble release sheet 1 and the floating bubble release sheet 2 to change unevenly, making one side expand. At this time, combined with the increased water pressure caused by the blockage, the impurities deposited at the significantly increased gap can be effectively washed away. Then, according to the data conditions of multiple tension sensors 51, the gathering positions of multiple deflecting clips 4 are changed multiple times, and the above process is repeated to achieve self-cleaning by bias. Compared with the method of the floating bubble release sheet 2 moving downward as a whole to expand the gap for unclogging in the prior art, the required water pressure is relatively small, the difficulty of flushing the impurities away is smaller, and the speed is faster. Thus, the blocked floating bubble release device can return to normal faster to maintain the stable progress of the air flotation process, and effectively ensure the efficiency of wastewater treatment.

[0027] In the above-mentioned process for treating benzohydroxamic acid oximation production wastewater, the wastewater is treated by combining extraction and air flotation, effectively achieving low emissions and a high recovery rate of methyl benzoate, thereby effectively reducing the difficulty and cost input of wastewater treatment. And under the action of the floating bubble release device, self-cleaning by bias can be achieved. Compared with the overall synchronous cleaning in the prior art, the speed of unclogging is effectively increased, and the impact on the efficiency of wastewater treatment is reduced.

[0028] The second implementation mode: Based on the first implementation mode, this implementation mode further improves the floating bubble release sheet 2, and the rest is the same as the first implementation mode.

[0029] Figure 10It is shown that the floating bubble releasing sheet 2 includes a positioning plate 21, a pre-floating layer 22 fixedly connected to the outer circle of the positioning plate 21, and a plurality of bubble releasing outer rings 23 respectively fixedly connected to the outer circle of the pre-floating layer 22. A plurality of limiting rods are connected between the positioning plate 21 and the fixed bubble releasing sheet 1. The middle parts 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, and the bubble releasing outer ring 23 is a rigid elastic structure. The connection position between the lower retaining ring 102 and the floating bubble releasing sheet 2 is on the positioning plate 21. Through the settings of the pre-floating layer 22 and the bubble releasing outer ring 23, the outer circle of the floating bubble releasing sheet 2 can be subdivided, such as Figure 12 , so that each bubble releasing outer ring 23 can be inclined downward and deformed, thereby changing the interval between the bubble releasing outer ring and the fixed bubble releasing sheet 1, so that targeted local variable-gap opening and blocking can be realized. Compared with the first embodiment, the targeting is stronger, the opening and blocking effect on the floating bubble release device is better, and the speed is faster. The opening and blocking can be realized when the pressure is relatively small.

[0030] Such as Figures 13 - 14 , a deviation control unit is installed at the bottom of the floating bubble releasing sheet 2. The deviation 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 attached to the lower end of the positioning plate 21 and distributed in an annular array. A plurality of chutes corresponding to the plurality of reciprocating hard strips 62 are dug at the lower end of the positioning plate 21. An elastic telescopic rod 63 is installed on the inner wall of the chute away from the eccentric concave wheel 61. The extending end of the elastic telescopic rod 63 faces the side of the eccentric concave wheel 61 and is fixedly connected with a connecting block 601. The connecting block 601 is fixedly connected with the reciprocating hard strip 62.

[0031] One end of the eccentric concave wheel 61 is a cylindrical surface 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 abuts against 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 at 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 abuts against 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.

[0032] During the process of releasing bubbles, the rotation of the eccentric cam 61 can be controlled by the electric rotating shaft, so that the contact points between the multiple reciprocating hard strips 62 and the eccentric cam 61 change periodically. 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 horizontally along the lower surface of the floating bubble-releasing sheet 2. When contacting the cylindrical surface, it can support the corresponding bubble-releasing outer ring 23 to make it horizontal. When contacting the concave arc surface, the bubble-releasing outer ring 23 resets. At this time, the pre-floating layer 22 is not restricted, causing the corresponding bubble-releasing outer ring 23 to tilt downward, so that the multiple bubble-releasing outer rings 23 sequentially present a process of moving downward - horizontal - moving downward. Compared with the prior art, the outer ring of the floating bubble-releasing sheet 2 continuously floats. On the one hand, the gap can be continuously changed, making it difficult for impurities to overly adhere during the release process of the dissolved air water, and the probability of blockage can be greatly reduced. On the other hand, its dynamic state also makes the deposited part of the impurities easier to be washed away when tilted, thus prolonging the probability between two blockages.

[0033] In addition, it is worth noting that in this embodiment, when the blockage situation is relatively serious and it is difficult to clear the blockage, the multiple biasing clips 4 can also be controlled to gather towards the cylindrical surface side of the eccentric cam 61. At this time, the multiple unrestricted bubble-releasing outer rings 23 can tilt downward relatively more greatly, making the change range of the gap between the bubble-releasing outer ring 23 and the fixed bubble-releasing sheet 1 larger, accelerating the clearing of the blockage, so that the current air flotation process is not easily affected too much, ensuring the efficiency of wastewater treatment.

[0034] In summary, by combining extraction and air flotation to treat wastewater, it effectively realizes low emissions and high recovery rate of methyl benzoate, and can effectively reduce the usage amount of methyl benzoate in the oximation reaction process, thereby effectively reducing the difficulty and cost input of wastewater treatment. In addition, during the air flotation process, through the setting of the floating bubble release device, the situation of bubbles in the dissolved air water can be effectively monitored for timely regulation. And after the floating bubble release device is blocked, it can automatically control the bubble-releasing outer ring on it to present an indefinite floating state, so that the increased water pressure due to blockage can be concentrated on a fixed point for clearing the blockage. Compared with comprehensive and non-discriminatory synchronous blockage clearing, the required water pressure is relatively small, thereby greatly accelerating the recovery of the floating bubble release device, effectively ensuring the removal effect and efficiency of organic matter in the wastewater during the air flotation process.

[0035] Combined with the current actual needs, the above-mentioned implementation method adopted in this application, the protection scope is not limited to this. Within the scope of knowledge possessed by those skilled in the art, various changes made without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. A treatment process for the wastewater from the production of benzohydroxamic acid by oximation, characterized in that: It includes the following steps: S1. Filter press the reaction solution of the oximation reaction through a plate and frame filter press to obtain a filtrate; S2. Use methyl benzoate as an extractant to fully mix and stir with the filtrate for 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 a loaded ester; S3. The wastewater after extraction is further introduced into a flotation tank for flotation treatment to separate the entrained organic phase in the wastewater. The organic phase is the entrained methyl benzoate. A floating bubble release device and a laser scattering sensor are arranged at the bottom of the flotation tank; S31. Release the dissolved air water carrying high-density microbubbles into the flotation tank through the floating bubble release device, and capture and adhere to the organic matter particles in the wastewater through the bubbles to float upward to achieve flotation; S32. Detect the bubble condition in the flotation tank through the laser scattering sensor and adjust it to maintain the bubble volume within the expected range; S33. When the bubble volume becomes low and it is still difficult to callback after adjustment, it indicates that the floating bubble release device may be blocked. Control the outer ring of the bubble release of the floating bubble release device to present an indefinite floating state to achieve biased self-cleaning, so that the floating bubble release device returns to normal and maintains the stable progress of the flotation process; S41. After the water after flotation treatment is adjusted to neutral pH, it can be introduced into a multi-effect evaporation system for salt evaporation and concentration to recover industrial salt, and then achieve low emissions; S42. Part of the organic phase obtained after flotation and extraction is directly returned to the oximation reaction stage as a raw material, and part of the organic phase is purified through back extraction operation to obtain purified methyl benzoate. This part of the purified methyl benzoate can be recycled as the extractant in step S1, thereby reducing the consumption of new methyl benzoate and achieving 100% recovery; The floating bubble release device includes a fixed bubble release plate (1), a floating bubble release plate (2) opposite to the fixed bubble release plate (1), and a plurality of biasing clips (4) respectively installed between the edges of the fixed bubble release plate (1) and the floating bubble release plate (2). The biasing clips (4) are slidably connected to the fixed bubble release plate (1) and the floating bubble release plate (2) through an electric slide rail installed on the fixed bubble release plate (1). A water inlet pipe (3) is fixedly connected to the upper end of the fixed bubble release plate (1). A water inlet (101) is drilled in the middle of the upper end of the fixed bubble release plate (1). The water inlet (101) is coaxially arranged with the water inlet pipe (3). Upper retaining rings (103) and lower retaining rings (102) are respectively fixedly connected to the ends of the fixed bubble release plate (1) and the floating bubble release plate (2) close to each other, and both are coaxially arranged with the water inlet (101).

2. The hydroxylation production wastewater treatment process of benzohydroxamic acid according to claim 1, wherein: The sizes of the lower retaining ring (102) and the upper retaining ring (103) are different, 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 release plate (1) and floating bubble release plate (2).

3. A process for treating wastewater from the production of benzohydroxamic acid by oximation according to claim 2, characterized in that: A plurality of fixed floating ropes (104) are fixedly connected between the fixed bubble releasing sheet (1) and the floating bubble releasing sheet (2). When the plurality of deflecting clips (4) are all in the vertical state, the plurality of fixed floating ropes (104) are all in a relaxed state, and the fixed floating ropes (104) are made of a corrosion-resistant inelastic material.

4. A process for treating the wastewater from the production of benzohydroxamic acid by oximation according to claim 1, characterized in that: The deflecting clip (4) is in an E shape. The deflecting clip (4) includes two L-shaped clip arms (41) and a floating section fixedly connected between the two L-shaped clip arms (41). The L-shaped clip arm (41) includes 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 is arranged inside the floating layer (422). The interval between the floating section and the L-shaped clip arm (41) matches the fixed bubble releasing sheet (1).

5. A process for treating the wastewater from the production of benzohydroxamic acid by oximation according to claim 4, characterized in that: An electromagnetic sheet (401) is fixedly embedded inside the positioning layer (421). After the two electromagnetic sheets (401) are electrified, magnetic repulsion is generated between them. The positioning layer (421) is a rigid elastic structure, and the floating layer (422) is a highly elastic structure.

6. The wastewater treatment process for the production of benzohydroxamic acid by oximation according to claim 5, characterized in that: 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 an elastic material. When the deflecting clip (4) is in the vertical and unloaded state, the trigger rope (52) is just in a straightened state.

7. A process for treating the wastewater from the hydroxylation production of benzohydroxamic acid according to claim 6, characterized in that: The floating bubble releasing sheet (2) includes a positioning plate (21), a pre-floating layer (22) fixedly connected to the outer circle of the positioning plate (21), and a plurality of bubble releasing outer rings (23) respectively fixedly connected to the outer circle of the pre-floating layer (22). A plurality of limiting rods are connected between the positioning plate (21) and the fixed bubble releasing sheet (1). The middle parts of the plurality of bubble releasing outer rings (23) correspond to the plurality of deflecting clips (4) respectively. The pre-floating layer (22) is an elastic structure, and the bubble releasing outer ring (23) is a rigid elastic structure. The connection part between the lower retaining ring (102) and the floating bubble releasing sheet (2) is located on the positioning plate (21).

8. A process for treating the wastewater from the production of benzohydroxamic acid by oximation according to claim 7, characterized in that: A deviation control unit is installed at the bottom of the floating bubble releasing sheet (2). The deviation control unit includes an eccentric cam (61) installed at the lower end of the positioning plate (21) through an electric rotating shaft and a plurality of reciprocating hard strips (62) arranged in an annular array and attached to the lower end of the positioning plate (21). A plurality of chutes corresponding to the plurality of reciprocating hard strips (62) are dug at the lower end of the positioning plate (21). An elastic telescopic rod (63) is installed on the inner wall of the chute far from the eccentric cam (61). The extending end of the elastic telescopic rod (63) faces the side of the eccentric cam (61) and is fixedly connected with a connecting block (601). The connecting block (601) is fixedly connected with the reciprocating hard strip (62).

9. The treatment process for the wastewater produced in the oximation of benzohydroxamic acid according to claim 8, characterized in that: One end of the eccentric cam (61) is a cylindrical structure, and the other end of the eccentric cam (61) is an arc-shaped concave structure with an arc transition; When the end of the reciprocating rigid bar (62) abuts against the cylindrical surface of the eccentric cam (61), the other end of the reciprocating rigid bar (62) crosses over the pre-floating layer (22) and contacts the lower surface of the bubble-releasing outer ring (23), and the cross-section at this position is not less than 1 / 3 of the radial span of the bubble-releasing outer ring (23); When the end of the reciprocating rigid bar (62) abuts against the concave arc surface of the eccentric cam (61), the other end of the reciprocating rigid bar (62) corresponds to the edge of the pre-floating layer (22) on the side close to the eccentric cam (61).

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