Desulfurized brine separation and purification apparatus and method

Abstract

This invention discloses a desulfurization brine separation and purification device and method, including a hydrocyclone, a foam cylinder, and a pump body. The foam cylinder is coaxially mounted on the flared end of the upper part of the hydrocyclone. A discharge pipe is provided at the bottom of the hydrocyclone, and an air inlet pipe and a feed pipe are provided in the middle of the hydrocyclone. The air inlet pipe passes through the hydrocyclone and extends into its interior, while the feed pipe is horizontally tangential to the hydrocyclone. A drain pipe is provided inside the hydrocyclone, with one end connected to the liquid inlet of the pump body and the other end passing through the foam cylinder and extending vertically to the center of the hydrocyclone's interior. This invention adds phosphate to desulfurization wastewater to react and generate magnesium ammonium phosphate precipitate, forming a mixed liquid. A collector is added to the mixed liquid and discharged into the separation and purification device. The upper part containing magnesium ammonium phosphate foam and the lower part precipitated gypsum are collected and separated. This not only reduces the chloride ion content in the gypsum, a byproduct of desulfurization wastewater treatment, but also simultaneously recovers high-value magnesium ammonium phosphate, reducing the enterprise's wastewater treatment costs.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a desulfurized brine separation and purification device and method. Background Technology

[0002] The application of wet desulfurization technology for sintering flue gas is a primary means for power plants and the steel industry to control sulfide emissions and an important pathway to control sulfur dioxide (SO2) emissions. Wastewater generated by wet desulfurization does not meet environmental protection requirements and must be treated to meet standards before discharge. How to effectively recover and utilize the salts in the desulfurization wastewater to generate maximum economic benefits is a goal pursued by enterprises. In addition to calcium sulfate gypsum, the wastewater generated by wet desulfurization also contains impurities such as chloride ions, magnesium ions, and ammonia nitrogen compounds. During subsequent filtration and concentration, insoluble magnesium ammonium chloride is generated, resulting in a large amount of chloride ions in the recovered gypsum, reducing the purity and quality of the gypsum.

[0003] Patent 202111293158.9 discloses a method for improving the purity of by-products from wet desulfurization wastewater. This method involves adding ferrous salts to the wastewater to be concentrated, causing the ferrous salts to preferentially react with magnesium ions and ammonia nitrogen compounds to form stable ferrous ammonium sulfite. This effectively prevents ammonia nitrogen from precipitating as magnesium ammonium chloride, allowing subsequent filtration to separate chloride ions from the gypsum. While this method reduces the chloride ion content in gypsum, ferrous ammonium sulfite remains. Since ferrous ammonium sulfite itself has limited utilization value, it is not further separated, resulting in no effective improvement in gypsum purity. Simultaneously, the authors proposed a magnesium ammonium phosphate method to reduce chloride ion content, but this also lacks subsequent separation. Magnesium ammonium phosphate has higher utilization value than ferrous ammonium sulfite, as it can be used as a feed additive, fertilizer additive, and pharmaceutical feed. Therefore, further research is needed to achieve harmless treatment of desulfurization wastewater and the separation and recovery of high-purity gypsum. This not only has high economic value but also aligns with environmental protection requirements. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a desulfurization brine separation and purification device and method to solve the problem of low purity in the gypsum recovered from desulfurization wastewater.

[0005] The objective of this invention is achieved through the following technical solution: a desulfurized brine separation and purification device, comprising a hydrocyclone, a foam cylinder, and a pump body. The hydrocyclone has a conical structure, and the foam cylinder has a tubular structure. The foam cylinder is coaxially mounted on the flared end of the upper part of the hydrocyclone. A discharge pipe is provided at the bottom of the hydrocyclone. An air inlet pipe and a feed pipe are provided in the middle of the hydrocyclone. The air inlet pipe passes through the hydrocyclone and extends into its interior. The feed pipe is horizontally tangential to the hydrocyclone. A liquid drain pipe is provided inside the hydrocyclone. One end of the liquid drain pipe is connected to the liquid inlet end of the pump body, and the other end of the liquid drain pipe passes through the foam cylinder and extends vertically to the interior center of the hydrocyclone.

[0006] Preferably, the drain pipe has an inverted U-shaped structure, and a separation pipe is provided on the drain pipe. Both ends of the separation pipe are connected to the drain pipe, and an air extraction pipe is connected to the drain pipe section located between the two ends of the separation pipe.

[0007] Preferably, the foam cylinder is provided with an annular sealed material collection bin and a liquid collection bin arranged sequentially from the inside to the outside. The side wall of the material collection bin is provided with multiple filter holes communicating with the liquid collection bin. The drain pipe is provided with a bearing, a connecting frame, a scraper, and a pusher plate. The pusher plate is a rectangular plate structure, and the plate surface of the pusher plate is parallel to the axis of the cyclone cylinder. The bearing is fitted outside the drain pipe. The scraper is located at the bottom of the material collection bin, and the side of the scraper abuts against the inner wall of the material collection bin. One part of the connecting frame is fixedly connected to the outer ring of the bearing, and the other part of the connecting frame is fixedly connected to the pusher plate and the scraper respectively. The bottom of the liquid collection bin is provided with a liquid outlet pipe. A Venturi injector is provided outside the cyclone cylinder. The feed end of the Venturi injector is connected to the liquid outlet pipe, and the discharge end of the Venturi injector is connected to the air inlet pipe.

[0008] Preferably, the scraper is provided with a defoaming mechanism, which includes a rolling column, a connecting rod, and a spring. The rolling column is horizontally rolled on the bottom surface of the collection bin. One end of the connecting rod is hinged to the rotating shaft of the rolling column, and the other end of the connecting rod is hinged to the scraper. One end of the spring is fixedly connected to the middle of the connecting rod, and the other end of the spring is fixedly connected to the scraper. The spring contracts and presses down to make the rolling column fit tightly against the bottom surface of the collection bin. The defoaming mechanism is installed in front of the scraper in the direction of rotation.

[0009] Preferably, the bottom of the collection bin is provided with a jacket, and the jacket is used to introduce hot fluid to heat the bottom surface of the collection bin.

[0010] Preferably, the scraper has an L-shaped structure, the scraper abuts against the bottom surface of the collection bin, and the bottom surface of the collection bin is provided with a discharge port.

[0011] Preferably, a filter screen is provided on the drain pipe, the filter screen is installed at the port of the drain pipe, and the upper edge of the push plate is in close contact with the surface of the filter screen.

[0012] The present invention also discloses a method for separating and purifying desulfurized brine, comprising the following steps:

[0013] S1. Adjust the pH of the desulfurization wastewater to 8-10;

[0014] S2. Adding phosphate reacts to generate magnesium ammonium phosphate precipitate and forms a mixed solution;

[0015] S3. Add a collector to the mixture and discharge it into a separation and purification device. Pass gas through the mixture and collect and separate the foam containing magnesium ammonium phosphate in the upper part and the precipitated gypsum in the lower part.

[0016] Preferably, the collector is sodium oleate and dodecylamine.

[0017] Preferably, the phosphate is one or more of sodium phosphate and ammonium phosphate.

[0018] The present invention has the following advantages:

[0019] 1. By forming magnesium ammonium phosphate precipitate, the synthesis of magnesium ammonium chloride is inhibited, thereby reducing the chloride ion content in gypsum and improving the quality of gypsum.

[0020] 2. By adding a collector and using flotation to separate magnesium ammonium phosphate from gypsum, not only is the purity of gypsum improved, but high-value products can also be recovered, which has high economic value and reduces wastewater treatment costs.

[0021] 3. By designing specialized separation and purification equipment, gypsum and magnesium ammonium phosphate can be separated rapidly at the same time, shortening the processing steps and improving production efficiency. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Schematic diagram of the half-section structure;

[0024] Figure 3 yes Figure 2 Front view of the structural diagram;

[0025] Figure 4 yes Figure 2 A magnified structural diagram at point A in the middle.

[0026] In the diagram, 1. Cyclone drum; 2. Foam cylinder; 3. Discharge pipe; 4. Feed pipe; 5. Air inlet pipe; 6. Liquid discharge pipe; 7. Pump body; 8. Separation pipe; 9. Suction pipe; 10. Collection bin; 11. Liquid collection bin; 12. Filter hole; 13. Discharge port; 14. Liquid outlet pipe; 15. Venturi ejector; 16. Push plate; 17. Bearing; 18. Connecting frame; 19. Scraper; 20. Jacket; 21. Filter screen; 22. Accumulation section; 23. Spiral separation section; 24. Foam section; 25. Re-separation section; 26. Foam accumulation section; 27. Roller column; 28. Connecting rod; 29. ​​Spring. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] A method for separating and purifying desulfurized wastewater includes the following steps: adding quicklime to the desulfurized wastewater to adjust the pH to 8-10, adjusting the temperature to 50-65℃, adding sodium phosphate to react and generate magnesium ammonium phosphate precipitate and form a mixed solution, adding a mixed collector of sodium oleate and dodecylamine to the mixed solution and stirring to mix evenly, then discharging into a dedicated separation and purification device, introducing gas, collecting and separating the upper part containing magnesium ammonium phosphate foam and the lower part precipitated gypsum.

[0030] The above method relies on a desulfurized brine separation and purification device of the present invention, which can simultaneously separate magnesium ammonium phosphate, gypsum, and wastewater. The specific structure is as follows: Figure 1As shown, the system includes a cyclone separator 1, a foam cylinder 2, and a pump body 7. The cyclone separator 1 has a conical structure, and the foam cylinder 2 has a tubular structure. The top diameter of the foam cylinder 2 is the same as that of the cyclone separator 1. The foam cylinder 2 is coaxially and sealed on the upper part of the cyclone separator 1. A discharge pipe 3 is installed at the center of the bottom of the cyclone separator 1. An air inlet pipe 5 and a feed pipe 4 are installed in the middle of the cyclone separator 1. The air inlet pipe 5 passes through the cyclone separator 1 and extends into its interior. The air inlet pipe 5 is used to blow air into the cyclone separator 1 to form a large number of bubbles. The feed pipe 4 is installed on... Above the air inlet pipe 5, the feed pipe 4 is horizontally tangential to the cyclone cylinder 1. The feed pipe 4 is filled with a mixture containing a collector. The feed pipe 4 causes the discharged mixture to rotate and centrifuge. Under the action of centrifugal force, the gypsum is thrown towards the inner wall of the cyclone cylinder 1 and continuously deposited at the bottom under the action of gravity. A large number of bubbles generated by the air inlet pipe 5 will carry the collector and magnesium ammonium phosphate upward in the form of foam to the foam cylinder 2 and accumulate. When it exceeds the edge of the foam cylinder 2, it will overflow outward.

[0031] like Figure 2 As shown, an annular sealed collection bin 10 and a liquid collection bin 11 are installed sequentially from the inside to the outside of the foam cylinder 2. Multiple filter holes 12 communicating with the liquid collection bin 11 are opened on the side wall of the collection bin 10. A drain pipe 6 is installed inside the cyclone cylinder 1. The drain pipe 6 has an inverted U-shaped structure. The inlet port of the drain pipe 6 vertically passes through the collection bin 10 and the foam cylinder 2 and extends into the cyclone cylinder 1. The drain pipe 6 is equipped with a bearing 17, a connecting frame 18, a scraper 19, and a pusher plate 16. The pusher plate 16 has a rectangular plate structure, and its surface is parallel to the axis of the cyclone cylinder 1, so that the vertical surface of the pusher plate 16 can push the mixture under the horizontal rotational motion of the mixture. The bearing 17 is mounted outside the drain pipe 6 and is installed above the top of the foam cylinder 2 to prevent the foam from obstructing the normal rotation of the bearing 17. The scraper 19 has an L-shaped structure and is located at the bottom of the collection bin 10. The sides of the scraper 19 abut against the inner wall and bottom surface of the collection bin 10, so that the scraper 19 can scrape off the accumulated material on the inner wall and bottom surface of the collection bin 10. The bottom surface of the collection bin 10 has a discharge port 13. The discharge port 13 is not limited to a circular tubular structure. One part of the connecting frame 18 is fixedly connected to the outer ring of the bearing 17, and the other part of the connecting frame 18 is fixedly connected to the push plate 16 and the scraper 19. The liquid outlet pipe 14 is installed at the bottom of the liquid collection bin 11.

[0032] like Figure 4As shown, a defoaming mechanism is installed on the scraper 19. The defoaming mechanism includes a rolling column 27, a connecting rod 28, and a spring 29. The rolling column 27 is horizontally rolled on the bottom surface of the collection bin 10. One end of the connecting rod 28 is hinged to the rotating shaft of the rolling column 27, and the other end of the connecting rod 28 is hinged to the scraper 19. The spring 29 is installed below the connecting rod 28. One end of the spring 29 is fixedly connected to the middle of the connecting rod 28, and the other end of the spring 29 is fixedly connected to the scraper 19. The spring 29 is normally in a stretched state. When the spring 29 contracts and presses down, it makes the rolling column 27 fit tightly against the bottom surface of the collection bin 10. The defoaming mechanism is installed in front of the scraper 19 in the direction of rotation, that is, the rolling column 27 rotates around the drain pipe 6 as the center during continuous rolling, so that the rolling column 27 quickly squeezes and breaks the foam in front of it during rolling.

[0033] The bottom of the collection bin 10 is provided with a jacket 20, and hot fluid is introduced into the jacket 20 to heat the bottom surface of the collection bin 10. A venturi ejector 15 is provided outside the cyclone cylinder. The feed end of the venturi ejector 15 is connected to the liquid outlet pipe 14, and the discharge end of the venturi ejector 15 is connected to the air inlet pipe 5.

[0034] like Figure 3 As shown, the cyclone separator 1 is divided into a material accumulation section 22 and a spiral separation section 23. The foam cylinder 2 is the foam section 24. The mixed liquid introduced tangentially through the feed pipe 4 causes the liquid in the spiral separation section 23 to undergo a centrifugal rotation. The heavier gypsum is centrifuged and separated to the outside and eventually settles in the material accumulation section 22. The clear liquid in the middle of the cyclone separator 1 is pumped into the drain pipe 6 by the pump body 7. The air bubbles generated by the air discharged through the air inlet pipe 5 cause the magnesium ammonium phosphate in the spiral separation section 23 to be carried by the collector to the foam section 24. After the magnesium ammonium phosphate foam accumulates, it overflows and falls into the collection bin 10. The swirling liquid in the spiral separation section 23 pushes the pusher plate 16 to rotate. The pusher plate 16 drives the scraper plate 19 to rotate through the bearing 17 and the connecting frame 18. The scraper plate 19 drives the installed roller column 27 to rotate. 27 During the rolling process, the foam is squeezed and broken. The bottom surface of the collection bin 10 is heated by the jacket 20. After the broken foam comes into contact with the bottom surface of the collection bin 10, it will further liquefy and form liquid capture agent and magnesium ammonium phosphate solid. The negative pressure feed end of the Venturi injector 15 forms a negative pressure in the collection bin 11 through the liquid outlet pipe 14. Under the action of negative pressure, the liquid capture agent passes through the filter hole 12, the collection bin 11, and the liquid outlet pipe 14 in sequence into the Venturi injector 15, and finally mixes with the high pressure gas and is passed into the spiral separation section 23 for recycling. The generated magnesium ammonium phosphate solid will block the filter hole 12. The scraper 19 can not only clean off the blocked solid, but also scrape the flattened magnesium ammonium phosphate solid on the bottom surface of the collection bin 10 into the discharge port 13 for discharge.

[0035] like Figure 2As shown, a separation pipe 8 is installed in the middle of the drain pipe 6. The separation pipe 8 is horizontally set and both ends of the separation pipe 8 are connected to the drain pipe 6. An air extraction pipe 9 is connected to the section of the drain pipe 6 between the two ends of the separation pipe 8. One end of the drain pipe 6 is connected to the liquid inlet of the pump body 7. The other end of the drain pipe 6 passes through the foam cylinder 2 and extends vertically to the center of the vortex cylinder 1. A filter screen 21 is installed at the liquid inlet of the drain pipe 6.

[0036] like Figure 3 As shown, the drain pipe 6 is installed inside the spiral separation section 23. The supernatant and some magnesium ammonium phosphate foam containing the collector in the spiral separation section 23 are drawn into the drain pipe 6 by the pump body 7. Under the action of the inverted U-shaped drain pipe 6, the magnesium ammonium phosphate foam will continuously accumulate at the top to form a layer like... Figure 3 The foam accumulation section 26 shown has a re-separation section 26 formed at the front and rear ends of the drain pipe 6 to facilitate foam deflection and separation. In order to ensure continuous operation, the foam in the foam accumulation section 26 will be periodically discharged through the suction pipe 9. The separation pipe 8 can ensure the normal flow of liquid in the drain pipe 6 when the foam accumulation section 26 continues to accumulate foam.

[0037] To reduce the amount of magnesium ammonium phosphate foam in the drain pipe 6, a filter screen 21 is installed at the port of the drain pipe 6. At the same time, the upper edge of the push plate 16 is in close contact with the surface of the filter screen 21. Under the rotational push of the water flow, the push plate 16 will continuously scrape off the solids accumulated and blocked on the surface of the filter screen 21, ensuring the stable flow of liquid in the drain pipe 6.

[0038] Working principle: Pump 7 is started, and simultaneously, a mixture and air are discharged into the cyclone separator 1 through the feed pipe 4 and the Venturi injector 15. The mixture flows downwards in a swirling state within the cyclone separator 1. The centrifugal force generated by the swirling flow throws the gypsum against the inner wall, where it settles and accumulates downwards under gravity, forming a state where the center is supernatant and the edges are gypsum mixture. The supernatant is discharged through the drain pipe 6 under the negative pressure suction of pump 7. The air bubbles formed by the air discharged through the air inlet pipe 5 adsorb magnesium ammonium phosphate and carry it into the foam cylinder 2. The foam continuously accumulates and overflows into the collection bin 10. Simultaneously, the rotation of the mixture pushes the pusher plate 16 to rotate, which in turn drives the scraper 19 and the roller 27 to move. The roller 27 then pushes the falling... The foam in front is crushed and squeezed, while the scraper 19 at the rear simultaneously scrapes off the magnesium ammonium phosphate solids on the bottom surface of the filter holes 12 and the collection bin 10. The jacket 20 heats the bottom surface of the collection bin 10 and further improves the fluidity of the collector. Under the action of the negative pressure port of the Venturi injector 15, the collector is sucked into the liquid outlet pipe 14 and finally mixed with the gas before being discharged back into the cyclone 1 for flotation of magnesium ammonium phosphate. The supernatant sucked in by the drain pipe 6 is mixed with a certain amount of collector and air bubbles. By setting the shape of the drain pipe 6 to an inverted U-shape, the foam can be collected in the foam accumulation section 26 before entering the pump body 7 and discharged through the suction pipe 9, maximizing the collection and separation of magnesium ammonium phosphate and collector, and also reducing the corrosion of the pump body 7.

[0039] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A desulfurized brine separation and purification device, characterized in that: The system includes a cyclone separator (1), a foam cylinder (2), and a pump body (7). The cyclone separator (1) has a conical structure, and the foam cylinder (2) has a tubular structure. The foam cylinder (2) is coaxially mounted on the flared end of the upper part of the cyclone separator (1). A discharge pipe (3) is provided at the bottom of the cyclone separator (1). An air inlet pipe (5) and a feed pipe (4) are provided in the middle of the cyclone separator (1). The air inlet pipe (5) passes through the cyclone separator (1) and extends into its interior. The feed pipe (4) is connected to the... The cyclone separator (1) is horizontally tangentially arranged, and a drain pipe (6) is provided inside the cyclone separator (1). One end of the drain pipe (6) is connected to the inlet end of the pump body (7), and the other end of the drain pipe (6) passes through the foam cylinder (2) and extends vertically to the center of the cyclone separator (1). An annular sealed collection bin (10) and a liquid collection bin (11) are arranged sequentially from the inside to the outside on the foam cylinder (2). Multiple [unclear] structures are provided on the side wall of the collection bin (10) that are connected to the liquid collection bin (11). Each filter hole (12) is provided with a bearing (17), a connecting frame (18), a scraper (19), and a pusher plate (16) on the drain pipe (6). The pusher plate (16) is a rectangular plate structure, and the plate surface of the pusher plate (16) is parallel to the axis of the cyclone separator (1). The bearing (17) is fitted outside the drain pipe (6). The scraper (19) is located at the bottom of the collection bin (10), and the side of the scraper (19) abuts against the inner wall of the collection bin (10). A portion of the connecting frame (18) is fixedly connected to the outer ring of the bearing (17), and the other portion of the connecting frame (18) is fixedly connected to the push plate (16) and the scraper (19). A liquid outlet pipe (14) is provided at the bottom of the liquid collection chamber (11), and a Venturi injector (15) is provided outside the vortex cylinder (1). The feed end of the Venturi injector (15) is connected to the liquid outlet pipe (14), and the discharge end of the Venturi injector (15) is connected to the air inlet pipe (5).

2. The desulfurized brine separation and purification equipment according to claim 1, characterized in that: The drain pipe (6) has an inverted U-shaped structure. A separation pipe (8) is provided on the drain pipe (6). Both ends of the separation pipe (8) are connected to the drain pipe (6). An air extraction pipe (9) is connected to the drain pipe (6) on the section between the two ends of the separation pipe (8).

3. The desulfurized brine separation and purification equipment according to claim 1, characterized in that: The scraper (19) is provided with a defoaming mechanism, which includes a rolling column (27), a connecting rod (28), and a spring (29). The rolling column (27) is horizontally rolled on the bottom surface of the collection bin (10). One end of the connecting rod (28) is hinged to the rotating shaft of the rolling column (27), and the other end of the connecting rod (28) is hinged to the scraper (19). One end of the spring (29) is fixedly connected to the middle part of the connecting rod (28), and the other end of the spring (29) is fixedly connected to the scraper (19). The spring (29) contracts and presses down to make the rolling column (27) fit tightly against the bottom surface of the collection bin (10). The defoaming mechanism is installed in front of the scraper (19) in the direction of rotation.

4. The desulfurized brine separation and purification equipment according to claim 3, characterized in that: The bottom of the collection bin (10) is provided with a jacket (20), and the jacket (20) is used to introduce hot fluid to heat the bottom surface of the collection bin (10).

5. The desulfurized brine separation and purification equipment according to claim 4, characterized in that: The scraper (19) has an L-shaped structure and abuts against the bottom surface of the collection bin (10). The bottom surface of the collection bin (10) is provided with a discharge port (13).

6. The desulfurized brine separation and purification equipment according to claim 5, characterized in that: A filter screen (21) is provided on the drain pipe (6). The filter screen (21) is installed at the port of the drain pipe (6). The upper edge of the push plate (16) is in close contact with the surface of the filter screen (21).

Images