A process and apparatus for treating industrial waste liquid from ethyl acetate production.

Abstract

This invention relates to the field of ethyl acetate wastewater treatment technology, specifically to a process and apparatus for treating industrial ethyl acetate wastewater, comprising the following steps: S1. Removing larger solid impurities from the wastewater using a grid; S2. Homogenizing and equalizing the wastewater obtained in S1 using an equalization tank; S3. Removing ethyl acetate, suspended solids, and some organic matter from the wastewater obtained in S2 through air flotation; S4. Performing biochemical treatment and aerobic biological treatment on the wastewater obtained in S3 sequentially using an anaerobic bioreactor and activated sludge process; S5. Performing flocculation treatment on the wastewater obtained in S4, followed by disinfection, and finally discharging. This invention, through steps S1-S5, sequentially intercepts larger impurities, homogenizes and equalizes the wastewater, performs air flotation treatment, reduces COD, reduces organic matter, removes flocs, and sterilizes, thereby removing ethyl acetate from the industrial wastewater and simultaneously purifying the wastewater for discharge or reuse.

Description

Technical Field

[0001] This invention relates to the field of ethyl acetate wastewater treatment technology, specifically to a process and apparatus for treating ethyl acetate industrial wastewater. Background Technology

[0002] Ethyl acetate is a commonly used organic solvent in industries such as coatings, inks, adhesives, and pharmaceuticals. Industrial waste mainly comes from cleaning, distillation residues, and product separation processes during production. For example, in the coatings industry, it contains impurities such as pigments and resins; in the ink industry, it may contain heavy metal additives; and in the pharmaceutical industry, it may be mixed with other organic solvents. Ethyl acetate is volatile, highly water-soluble (about 3%), and has low toxicity but is irritating.

[0003] Currently, for wastewater containing ethyl acetate, the air flotation method is used to remove ethyl acetate, suspended solids, and some organic matter from the wastewater. The equipment used is an air flotation machine. The air flotation machine is a water treatment device that uses an air flotation release device in a dissolved air system to generate a large number of microbubbles in the water. This causes the air to adhere to the suspended particles in the form of highly dispersed microbubbles, resulting in a density less than that of water. The buoyancy principle is used to make them float on the water surface, thereby achieving solid-liquid separation. Initially, when the air flotation machine was removing scum from the liquid surface, the liquid level was directly allowed to just cover the isolation plate of the tank, allowing the scum to flow directly into the scum tank along with some of the wastewater. However, this puts a lot of pressure on the wastewater filtration device in the scum tank.

[0004] The improved method involves installing a scum scraper on the surface of the flotation machine, as seen in the structures in invention patents CN118125543A and CN118877997A. This method uses a chain-driven scraper to scrape the scum from one end of the flotation machine to the scum tank at the other end, aiming to scrape as much scum as possible while minimizing the amount of waste liquid that enters the scum tank. Although this solves the problem of a large amount of waste liquid entering the scum tank along with the scum, the scum removal becomes intermittent scraping instead of continuous cleaning. As a result, more scum floats on the side of the tank near the flotation release device, and the buoyancy of the liquid can only support a certain thickness of scum. This necessitates either increasing the number of scrapers or increasing their operating speed. Therefore, we provide a new scum treatment device.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to design a process and apparatus for treating industrial wastewater from ethyl acetate, which continuously treats scum and reduces the amount of wastewater entering the scum tank, thereby addressing the aforementioned shortcomings in the technology.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an ethyl acetate industrial wastewater treatment device for separating scum from ethyl acetate industrial wastewater by air flotation treatment, comprising an upward-opening box, an air flotation release device installed at one end of the box, and an isolation plate fixedly installed inside the box, forming a scum trough between the isolation plate and the box, wherein multiple arrayed drive shafts are rotatably mounted between the isolation plate and the box, each drive shaft having a helical blade, wherein a section of the helical blade near the scum trough is not fixedly connected to the drive shaft, and a section of the helical blade away from the scum trough is fixedly connected to the drive shaft, wherein a positioning plate is fixedly installed on the drive shaft near the scum trough, and a spring is fixedly installed between the positioning plate and the helical blade, wherein a toggle element is installed inside the box, and the surface of the section of the helical blade not fixedly connected to the drive shaft mates with the surface of the toggle element;

[0008] The rotating helical blades push the floating scum inside the tank to the isolation plate. As the helical blades come into contact with the actuating element, they gradually compress and stretch the spring away from the scum trough. When the helical blades separate from the actuating element, the helical blades push the floating scum into the scum trough under the action of the spring.

[0009] Preferably, the actuating component includes a connecting plate fixedly connected to the housing, a plurality of vertical plates fixedly installed on the connecting plate, and actuating blocks fixedly installed on the vertical plates, wherein one actuating block corresponds to one of the spiral blades and is in contact with it.

[0010] Preferably, the spiral blade includes a fixed blade fixedly connected to the drive shaft and a pushing blade slidably connected to the drive shaft. The end of the pushing blade is fixedly connected to the end of the fixed blade, and the other end of the pushing blade is fixedly connected to the end of the spring. The pushing blade is in contact with the side of the actuating block. When the pushing blade rotates, it is restricted by the actuating block and the pitch is reduced along the drive shaft.

[0011] Preferably, the distance between the two drive shafts is less than the outer diameter of the helical blade and greater than 1 / 2 the outer diameter of the helical blade.

[0012] Preferably, when the pitch of the pushing blade decreases and the corresponding spring is stretched, neither the spring nor the pushing blade comes into contact with the vertical plate.

[0013] Preferably, a horizontally arranged baffle is fixedly installed on the side of the isolation plate near the pushing blade, and when the pitch of the pushing blade is not reduced, there is a gap between the pushing blade and the isolation baffle.

[0014] Preferably, a triangular plate is fixedly installed between the isolation plate and the connecting plate, and an unsealed receiving cavity is formed between the top of the triangular plate and the side wall of the connecting plate.

[0015] Preferably, the top surfaces of the actuating block and the vertical plate, as well as the central axis of the transmission shaft, are all in the same horizontal plane.

[0016] Preferably, the bottom of the inner cavity of the box has multiple sedimentation tanks, a partition plate is fixedly installed on the bottom surface of the inner cavity of the box, a water inlet pipe is fixedly installed on one side of the box, and a drain pipe is fixedly installed on the other side of the box.

[0017] Preferably, each end of the drive shaft passes through the housing and is fixedly mounted with a drive wheel, and a driven wheel that is rotatably connected to the side wall of the housing meshes between two adjacent drive wheels, and a pulley is also mounted on one of the drive shafts;

[0018] Secondly, the present invention also provides a processing method for operating the above-mentioned ethyl acetate industrial wastewater treatment device to treat the wastewater, comprising the following steps:

[0019] S1. A grid is used to remove larger solid impurities from the waste liquid;

[0020] S2. Homogenize and equalize the waste liquid obtained in S1 using an equalization tank;

[0021] S3. The waste liquid obtained in S2 is treated by air flotation to remove ethyl acetate, suspended solids and some organic matter to form scum;

[0022] S4. The waste liquid obtained in S3 is subjected to biochemical treatment and aerobic biological treatment in sequence using an anaerobic bioreactor and activated sludge process.

[0023] S5. The waste liquid in S4 is subjected to flocculation treatment, then disinfected, and finally discharged.

[0024] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0025] The present invention sequentially performs steps S1-S5 to intercept large impurities, homogenize and equalize quantities, perform air flotation treatment, reduce COD, reduce organic matter, remove flocs and sterilize the waste liquid, thereby removing ethyl acetate from the industrial waste liquid and purifying the wastewater for discharge or utilization.

[0026] This invention uses an array of spiral blades on the housing to automatically push the scum on one side of the air flotation release device to the side of the scum trough when the spiral blades rotate, preventing the scum from accumulating on one side of the air flotation release device and allowing for continuous cleaning of the scum.

[0027] Meanwhile, the present invention sets the spiral blades as fixed blades and pushing blades. Combined with the cooperation between the actuating component, spring and positioning plate, the transmission shaft drives the spiral blades to rotate once, pushing the scum on one side of the isolation plate into the scum tank, thus cleaning the scum. Compared with cleaning the scum with flowing waste liquid when the liquid level just overflows the isolation plate, this invention reduces the amount of waste liquid entering the scum tank.

[0028] Meanwhile, the invention installs a triangular plate and a baffle on one side of the isolation plate, so that when the spiral blade pushes scum and waste liquid towards the isolation plate, the waste liquid below hits the triangular plate and the isolation plate and then folds back under the baffle, colliding with the waste water pushed above the spiral blade, thereby briefly raising the liquid level. This makes it easier for the part of the spiral blade above the isolation plate to push more scum on the liquid surface into the scum tank. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0030] Figure 1 This is a flow chart of the ethyl acetate industrial wastewater treatment process of the present invention;

[0031] Figure 2 This is a simplified schematic diagram of the processing apparatus of the present invention containing scum;

[0032] Figure 3 This is a schematic diagram of the internal structure of the processing device of the present invention;

[0033] Figure 4 This is a top view of the processing device of the present invention;

[0034] Figure 5 This is a side sectional view of the processing device of the present invention;

[0035] Figure 6 This is a schematic diagram showing the distribution of the spiral blades and the actuating element of the present invention;

[0036] Figure 7 This is a side view of the spiral blade and the actuating element of the present invention;

[0037] Figure 8 This is a perspective view of the toggle element of the present invention.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1. Housing; 2. Air flotation release device; 3. Isolation plate; 4. Scum trough; 5. Drive shaft; 6. Spiral blade; 6a. Fixed blade; 6b. Pushing blade; 7. Positioning plate; 8. Spring; 9. Actuating element; 9a. Connecting plate; 9b. Vertical plate; 9c. Actuating block; 10. Baffle; 11. Triangular plate; 12. Receiving cavity; 13. Scum trough; 14. Divider plate; 15. Water inlet pipe; 16. Drain pipe; 17. Drive wheel; 18. Driven wheel; 19. Pulley. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0042] This invention provides, for example Figure 2-8 The device shown is for treating ethyl acetate industrial wastewater by air flotation. It includes an upward-opening box 1 of the air flotation machine itself. The bottom of the inner cavity of the box 1 has multiple sedimentation tanks 13 and a partition plate 14. Between the partition plate 14 and the inner wall of the box 1, there is an inlet pipe 15 and an air flotation release device 2 installed on the box 1. A partition plate 3 is installed to form a sedimentation tank 4. At the same time, a drain pipe 16 is installed on the side of the box 1 away from the inlet pipe 15. When the inlet pipe 15 discharges wastewater into the space between the partition plate 14 and the inner wall of the box 1, the air flotation release device 2 releases a large number of microbubbles. The air is attached to the suspended particles of the wastewater in the form of highly dispersed microbubbles, resulting in a state where the density is less than that of water. Using the principle of buoyancy, the particles float on the water surface. Some of the larger particles will settle into the sedimentation tanks 13. The water filtered in the middle layer is discharged through the drain pipe 16.

[0043] We rotatably install multiple arrayed drive shafts 5 between the isolation plate 3 and the housing 1. A helical blade 6 is mounted on each drive shaft 5. The section of the helical blade 6 closest to the isolation plate 3 is not welded to the drive shaft 5, but rather directly fitted onto it for sliding connection, forming a pushing blade 6b. A large section of the helical blade 6 furthest from the isolation plate 3 is welded to the drive shaft 5, forming a fixed blade 6a. A drive wheel 17 is fixedly mounted at the end of each drive shaft 5. A driven wheel 18, rotatably connected to the side wall of the housing 1, meshes between two adjacent drive wheels 17. A pulley 19 is also mounted on one of the drive shafts 5. By controlling the flow rate of the inlet pipe 15 and the outlet pipe 16, we can control the height of the liquid level, thereby controlling the height of the scum floating on the liquid level. The height of the liquid level is best to be on the same horizontal plane as the central axis of the drive shaft 5. When the pulley 19 drives the drive shaft 5 to rotate, the drive shaft 5 will rotate synchronously through the meshing of the drive wheel 17 and the driven wheel 18, thereby driving the spiral blade 6 to rotate synchronously. This will cause the scum from one side of the tank 1 to be gradually driven to the side of the tank 1 closer to the isolation plate 3. At this time, the amount of scum on the liquid surface of the tank 1 closer to the isolation plate 3 is greater than the amount on the other side of the tank 1.

[0044] At this point, we fix and install the connecting plate 9a inside the housing 1. Multiple vertical plates 9b, matching the drive shaft 5, are fixedly installed on the connecting plate 9a. A toggle block 9c is fixedly installed on each vertical plate 9b. These three components constitute the toggle element 9. The toggle block 9c contacts the surface of the push blade 6b, such as... Figure 3 As shown, when the pusher blade 6b rotates counterclockwise, the pusher blade 6b is limited by contact with the surface of the actuating block 9c. The pusher blade 6b will gradually be squeezed axially by the transmission shaft 5, which reduces the pitch. When the transmission shaft 5 rotates one revolution, the pusher blade 6b separates from the actuating block 9c. The pusher blade 6b will have a reset motion under its own elasticity, generating a thrust on the liquid surface. In order to assist the reset of the pusher blade 6b, a positioning plate 7 is fixedly installed on the transmission shaft 5, and a spring 8 is fixedly installed between the positioning plate 7 and the pusher blade 6b. Therefore, the spring 8 is stretched as the pitch of the pusher blade 6b decreases, generating elastic force. This elastic force assists the reset of the pusher blade 6b and pushes the scum on the liquid surface to the isolation plate 3. After the scum overflows the isolation plate 3, it will be transferred into the scum tank 4. At the same time, a small amount of waste liquid will also enter the scum tank 4. The scum tank 4 is equipped with a liquid filtration and recovery device commonly used in the prior art, which can filter the small amount of waste liquid. This will not be elaborated here.

[0045] We set the distance between the two drive shafts 5 to be smaller than the outer diameter of the spiral blade 6 and larger than 1 / 2 the outer diameter of the spiral blade 6. This allows the spiral blade 6 to push the scum on the liquid surface to move when it rotates, thus preventing the scum from remaining suspended on the liquid surface between the two spiral blades 6 and not contacting the spiral blade 6.

[0046] The top surfaces of the actuating block 9c and the vertical plate 9b, as well as the central axis of the transmission shaft 5, are all set in the same horizontal plane. This allows the spiral blade 6 to be positioned at the same time as the actuating block 9c, so that the pushing blade 6b on the liquid surface can push the scum a certain distance further, reducing the pushing amount of the pushing blade 6b below the liquid surface, reducing the pushing amount of waste liquid, increasing the pushing amount of scum, and further improving the scum cleaning efficiency.

[0047] Furthermore, a triangular plate 11 is fixedly installed between the isolation plate 3 and the connecting plate 9a. An unsealed receiving cavity 12 is formed between the top of the triangular plate 11 and the side wall of the connecting plate 9a. Simultaneously, a horizontally positioned baffle 10 is fixedly installed on the side of the isolation plate 3 near the pushing blade 6b. When the pitch of the pushing blade 6b is not reduced, there is a gap between the pushing blade 6b and the isolation baffle 10. This gap prevents collisions. The baffle 10 also allows the pushing blade 6b to push a small amount of waste liquid and most of the scum, ensuring that the waste liquid is contained within the baffle. When the waste liquid is pushed by the blade 6b without overflowing the baffle 10, it will hit the triangular plate 11 and bounce back after entering the receiving cavity 12. It will collide with the waste liquid pushed by the blade 6b, which will cause the liquid level between the blade 6b and the baffle 10 to rise briefly. This will allow the blade 6b to push the scum of a certain thickness on and below the liquid surface into the scum tank 4. When the pitch of the blade 6b is reduced and the corresponding spring 8 is stretched, neither the spring 8 nor the blade 6b will contact the vertical plate 9b.

[0048] The specific workflow is as follows: Waste liquid enters the tank 1 through the inlet pipe 15. The air flotation release device 2 releases a large number of micro bubbles, causing ethyl acetate, suspended solids and some organic matter in the wastewater to form scum. Then, the pulley 19 rotates to drive all the spiral blades 6 to rotate, pushing the scum to one side of the isolation plate 3. Most of the scum on the liquid surface is continuously removed. During the rotation of the pushing blade 6b, the pitch of the screw is reduced due to the compression of the actuating part 9. When the actuating part 9 and the pushing blade 6b separate, the pushing blade 6b is reset under the action of the spring 8, thereby pushing the scum on one side of the isolation plate 3 into the scum tank 4, realizing the step of intermittently concentrating the scum in the tank 1 into the scum tank 4.

[0049] Combined with an ethyl acetate industrial waste liquid treatment device, such as Figure 1 As shown, the present invention also provides a processing technology for operating the above-mentioned ethyl acetate industrial waste liquid treatment device to treat the waste liquid, including the following steps;

[0050] S1: Use a screen to intercept larger solid impurities in the waste liquid, such as packaging materials and raw material residues, to prevent them from entering subsequent treatment equipment;

[0051] S2: Homogenization in the equalization tank. Due to the large fluctuations in the quality and quantity of waste liquid, the equalization tank is used to homogenize and equalize the quantity, so that the quality and quantity of waste liquid are relatively stable, which is convenient for subsequent treatment.

[0052] S3: Air flotation treatment. For waste liquid containing ethyl acetate, air flotation is used to remove ethyl acetate, suspended solids and some organic matter from the waste liquid.

[0053] S4: An anaerobic bioreactor is used to decompose some of the organic matter in the waste liquid into gases such as methane and carbon dioxide by anaerobic microorganisms, thereby reducing the COD of the waste liquid. Then, activated sludge process, biofilm process and other methods are used to further remove pollutants such as organic matter and ammonia nitrogen.

[0054] S5: Flocculation treatment is used to form suspended solids and colloids in the water into flocs, which are then removed by sedimentation tanks. Then, filtration methods such as sand filtration and activated carbon filtration are used to further remove organic matter and pollutants such as color from the waste liquid. After that, ultraviolet disinfection and chlorine dioxide disinfection are used to kill pathogenic microorganisms in the waste liquid, and finally it is discharged or reused.

[0055] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape and proportion of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application.

Claims

1. An ethyl acetate industrial wastewater treatment device for separating scum from wastewater by air flotation treatment, comprising an upward-opening tank (1), an air flotation release device (2) installed at one end inside the tank (1), and a partition plate (3) fixedly installed inside the tank (1), wherein a scum trough (4) is formed between the partition plate (3) and the tank (1), characterized in that: Multiple arrayed drive shafts (5) are rotatably installed between the isolation plate (3) and the box (1). The drive shafts (5) have helical blades (6). The section of the helical blades (6) near the scum trough (4) is not fixedly connected to the drive shafts (5), and the section of the helical blades (6) away from the scum trough (4) is fixedly connected to the drive shafts (5). A positioning piece (7) is fixedly installed on one end of the drive shaft (5) near the scum trough (4). A spring (8) is fixedly installed between the positioning piece (7) and the helical blades (6). A toggle piece (9) is installed inside the box (1). The surface of the section of the helical blades (6) that is not fixedly connected to the drive shafts (5) mates with the surface of the toggle piece (9). The spiral blades (6) rotate to push the floating scum in the box (1) to the isolation plate (3). The spiral blades (6) will gradually compress and stretch the spring (8) away from the scum trough (4) because they are in contact with the actuating element (9). When the spiral blades (6) separate from the actuating element (9), the spiral blades (6) push the floating scum into the scum trough (4) under the action of the spring (8).

2. The ethyl acetate industrial wastewater treatment device according to claim 1, characterized in that: The actuating component (9) includes a connecting plate (9a) fixedly connected to the housing (1), a plurality of vertical plates (9b) fixedly installed on the connecting plate (9a), and a toggle block (9c) fixedly installed on the vertical plate (9b). Each toggle block (9c) corresponds to one of the spiral blades (6) and is in contact with it.

3. The ethyl acetate industrial wastewater treatment device according to claim 2, characterized in that: The spiral blade (6) includes a fixed blade (6a) fixedly connected to the transmission shaft (5) and a push blade (6b) slidably connected to the transmission shaft (5). The end of the push blade (6b) is fixedly connected to the end of the fixed blade (6a), and the other end of the push blade (6b) is fixedly connected to the end of the spring (8). The push blade (6b) is in contact with the side of the actuating block (9c). When the push blade (6b) rotates, it is restricted by the actuating block (9c) and the pitch decreases along the transmission shaft (5).

4. The ethyl acetate industrial wastewater treatment device according to claim 3, characterized in that: The distance between the two drive shafts (5) is less than the outer diameter of the helical blade (6) and greater than 1 / 2 the outer diameter of the helical blade (6).

5. The ethyl acetate industrial wastewater treatment device according to claim 3, characterized in that: When the pitch of the pusher blade (6b) decreases and the corresponding spring (8) is stretched, neither the spring (8) nor the pusher blade (6b) comes into contact with the vertical plate (9b).

6. The ethyl acetate industrial wastewater treatment device according to claim 3, characterized in that: A horizontally arranged baffle (10) is fixedly installed on the side of the isolation plate (3) near the push blade (6b). When the pitch of the push blade (6b) is not reduced, there is a gap between the push blade (6b) and the isolation baffle (10).

7. The ethyl acetate industrial wastewater treatment device according to claim 2, characterized in that: A triangular plate (11) is fixedly installed between the isolation plate (3) and the connecting plate (9a), and an unsealed receiving cavity (12) is formed between the top of the triangular plate (11) and the side wall of the connecting plate (9a).

8. The ethyl acetate industrial wastewater treatment device according to claim 2, characterized in that: The top surfaces of the actuating block (9c) and the vertical plate (9b), as well as the central axis of the transmission shaft (5), are all in the same horizontal plane.

9. The ethyl acetate industrial wastewater treatment device according to claim 1, characterized in that: The bottom of the inner cavity of the box (1) has multiple sedimentation tanks (13), and a partition plate (14) is fixedly installed on the bottom surface of the inner cavity of the box (1). A water inlet pipe (15) is fixedly installed on one side of the box (1), and a drain pipe (16) is fixedly installed on the other side of the box (1). The ends of the drive shafts (5) all pass through the box (1) and are fixedly installed with drive wheels (17). A driven wheel (18) that is rotatably connected to the side wall of the box (1) meshes between two adjacent drive wheels (17). A pulley (19) is also installed on one of the drive shafts (5).

10. A process for treating ethyl acetate industrial wastewater, used to operate the ethyl acetate industrial wastewater treatment device according to any one of claims 1-9, characterized in that: Includes the following steps: S1. A grid is used to remove larger solid impurities from the waste liquid; S2. Homogenize and equalize the waste liquid obtained in S1 using an equalization tank; S3. The waste liquid obtained in S2 is treated by air flotation to remove ethyl acetate, suspended solids and some organic matter; S4. The waste liquid obtained in S3 is subjected to biochemical treatment and aerobic biological treatment in sequence using an anaerobic bioreactor and activated sludge process. S5. The waste liquid in S4 is subjected to flocculation treatment, then disinfected, and finally discharged.

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