Gas-liquid-solid three-phase mixing system for carbonation reaction of fly ash

Abstract

The invention discloses a gas-liquid-solid three-phase mixing system for a fly ash carbonation reaction. The gas-liquid-solid three-phase mixing system comprises a mixing tank and a driving mechanism, a feeding pipe is arranged at the top of the mixing tank, an air inlet pipe is arranged at the bottom of the mixing tank, an air outlet is further formed in the top, and cutting blades are further arranged at the bottom; the driving mechanism comprises a driving motor, and the driving motor is arranged on the mixing tank and is connected with the cutting blades through a rotating shaft. By using the gas-liquid-solid three-phase mixing system for the carbonation reaction of the fly ash, after flue gas is aerated, the cutting blades can cut large bubbles into small bubbles, and the small bubbles not only float slowly in slurry, but also can fully react with the slurry.

Description

A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction Technical Field

[0001] This invention relates to the field of waste incineration technology, specifically to a gas-liquid-solid three-phase mixing system for fly ash carbonation reaction. Background Technology

[0002] The flue gas generated from waste incineration is usually treated using a combination of technologies including SNCR denitrification, semi-dry reaction tower (lime slurry solution), dry deacidification (NaHCO3), activated carbon adsorption, and bag filter. This process generates fly ash containing a large amount of dust and reaction products, which needs to be collected and stabilized before being landfilled. However, the fly ash contains a high concentration of heavy metals that leach out, and direct landfilling would pollute the soil and groundwater.

[0003] Fly ash carbonation is a cutting-edge technology developed in recent years. It utilizes the reaction between CO2 in flue gas and calcium ions in fly ash to generate stable carbonates that adsorb heavy metal ions, significantly reducing the risk of heavy metal leaching and making landfill safer. In existing technologies, fly ash and wastewater are typically mixed to form a slurry. Flue gas is then released from the slurry, generating bubbles. As these bubbles rise, CO2 in the flue gas fixes the heavy metals in the fly ash. The residence time of the bubbles in the solid-liquid mixture directly determines the efficiency of fly ash carbonation in fixing heavy metals and calcium ions. However, existing mixing tanks typically allow bubbles to rise directly from the bottom to the top, resulting in a short residence time and insufficient reaction with the solid-liquid mixture. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a gas-liquid-solid three-phase mixing system for fly ash carbonation reaction, which can improve the reaction sufficiency of flue gas and solid-liquid mixture.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a gas-liquid-solid three-phase mixing system for fly ash carbonation reaction, comprising a mixing tank and a driving mechanism; the mixing tank is provided with a feed pipe at the top, an air inlet pipe at the bottom, an air outlet at the top, and a cutting blade at the bottom; the driving mechanism includes a driving motor, which is mounted on the mixing tank and connected to the cutting blade via a rotating shaft.

[0006] Fly ash and wastewater can be fed into the mixing tank through the feed pipe at the top, forming a solid-liquid mixture. Flue gas is fed into the mixing tank from the bottom through the air inlet pipe, and bubbles are aerated in the slurry. As the large bubbles formed by aeration rise, they are cut into smaller bubbles by the cutting blades driven by the motor. The bubbles gradually rise and are eventually discharged through the air outlet at the top.

[0007] The beneficial effects of the above-mentioned gas-liquid-solid three-phase mixing system for fly ash carbonation reaction are: after the flue gas is introduced, the cutting blades can cut large bubbles into small bubbles. The small bubbles not only float more slowly in the slurry, but also react more fully with the slurry.

[0008] Furthermore, the mixing tank is also provided with baffles. Multiple baffles are arranged sequentially and alternately on the inner walls of both sides of the mixing tank in a vertical direction. The end of the baffle away from the inner wall of the mixing tank is inclined downward, and the end is located below the upper baffle.

[0009] Multiple baffles allow bubbles to pass through channels formed by each baffle in sequence during their ascent, increasing the distance of the ascent path and thus further increasing the residence time of the bubbles in the slurry.

[0010] Furthermore, the bottom surface of the baffle is provided with sharp teeth arranged in a rectangular array.

[0011] As the bubbles rise, they come into contact with the bottom of each baffle and the spikes in sequence, thus being punctured and forming smaller bubbles.

[0012] Furthermore, the baffle is hinged to the inner wall of the mixing tank, and the baffles on both sides can rotate upward alternately.

[0013] Because the baffle is tilted downwards, rotating it upwards can prevent air bubbles from getting stuck at the angle between the baffle and the inner wall of the mixing tank.

[0014] Furthermore, the drive mechanism also includes gears, racks, and transmission components. Gears are provided at the hinges of the baffle and the mixing tank. The two racks are vertically and movably disposed on both sides of the mixing tank and mesh with multiple gears on both sides respectively. The drive motor is connected to the two racks through the transmission components and can drive the two racks to move alternately and reciprocally.

[0015] When the drive motor drives the cutting blade to rotate, it can also drive two racks to move back and forth alternately through the transmission components. When the racks move up and down, they can drive the gears to rotate, thereby driving the baffle to rotate inside the mixing tank, lifting it up or rotating it down.

[0016] Furthermore, the transmission component includes a rotating disk, which is rotatably disposed at the bottom of the mixing tank and connected to a rotating shaft. The rotating disk has a circumferential groove, and the bottom of the rack has a slider that is slidably connected to the groove. The groove has a downwardly convex arc section that can drive the rack to move upward.

[0017] As the rotating disk rotates, the slider of the rack also slides within the groove. When it rotates to the arc-shaped section where the groove bulges upward, it can drive the rack to move downward, and then upward again, thus causing the rack to drive the baffle to rotate upward and then downward.

[0018] Furthermore, the mixing tank is also equipped with multiple helical blade assemblies, which are respectively arranged in the gaps between multiple baffles and the inner wall of the mixing tank, and the propulsion direction of the helical blade assemblies is downward.

[0019] The spiral blade assembly is propelled downwards, which can generate a counter-thrust force on the bubbles, thereby slowing down the rising speed of the bubbles and increasing the residence time of the bubbles in the slurry.

[0020] Furthermore, the helical blade assembly includes a mounting bracket, helical blades, a second rotating shaft, and an insert rod. The mounting bracket is disposed on the inner wall of the mixing tank. The second rotating shaft is rotatably mounted on the mounting bracket. The helical blades are disposed on the second rotating shaft. An insertion hole is formed at the top of the second rotating shaft. A vertical groove and a helical groove are formed in the insertion hole. The top and bottom ends of the helical groove are respectively connected to the two ends of the vertical groove. A second sliding groove is formed at the bottom of the baffle. One end of the insert rod is slidably inserted into the insertion hole, and the end is provided with a second sliding block that can slidably connect with the helical groove and the vertical groove. The other end of the insert rod is slidably and rotatably disposed in the second sliding groove.

[0021] When the baffle rotates, it causes the insert rod to move up and down. One end of the insert rod slides and rotates relative to the groove two, while the other end slides into the insertion hole of the rotating shaft two. As the insert rod moves up and down, the slider two at the end also moves within the spiral groove and the vertical groove. The spiral groove drives the rotating shaft two to rotate on the mounting bracket, thereby causing the spiral blades to rotate and generating a downward thrust to slow the rise of the bubble. The vertical groove is used to allow the slider to slide back to the starting point of the spiral groove and prevents the rotating shaft two from rotating, thus avoiding the spiral blades reversing and generating suction.

[0022] Furthermore, the bottom of the mixing tank is also provided with a discharge pipe, and both the inlet pipe and the discharge pipe are provided with branch pipes, which are connected to the suction pump through the branch pipes.

[0023] The discharge pipe is used to discharge the slurry after use. The feed pipe and discharge pipe are connected to the suction pump through a branch pipe, which can circulate the slurry during use, which can not only improve the fluidity of the slurry, but also improve the uniformity of the slurry. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0025] Figure 1 is a front view of a gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to an embodiment of the present invention; Figure 2 is a schematic diagram of the spiral blade assembly of the gas-liquid-solid three-phase mixing system for fly ash carbonation reaction shown in Figure 1; Figure 3 is a schematic diagram of the insertion hole of the gas-liquid-solid three-phase mixing system for fly ash carbonation reaction shown in Figure 2; Reference numerals: 10-mixing tank, 11-feed pipe, 12-air inlet pipe, 13-air outlet, 14-cutting 15-blade, 15-baffle, 151-slide groove II, 16-discharge pipe, 17-suction pump; 20-drive mechanism, 21-drive motor, 211-rotating shaft, 22-gear, 23-rack, 231-slider, 24-rotating disk, 241-slide groove; 30-spiral blade assembly, 31-mounting bracket, 32-spiral blade, 33-rotating shaft II, 331-insertion hole, 332-spiral groove, 333-vertical groove, 34-insertion rod, 341-slider II. Detailed Implementation

[0026] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0027] Please refer to Figures 1 to 3. The present invention provides a gas-liquid-solid three-phase mixing system for fly ash carbonation reaction, including a mixing tank 10 and a driving mechanism 20. The mixing tank 10 is used for mixing fly ash, wastewater and flue gas, and the driving mechanism 20 can drive the internal components of the tank to work.

[0028] Specifically, the mixing tank 10 is provided with a feed pipe 11 at the top, an air inlet pipe 12 at the bottom, an air outlet 13 at the top, and a cutting blade 14 at the bottom. The drive mechanism 20 includes a drive motor 21, which is mounted on the mixing tank 10 and connected to the cutting blade 14 via a rotating shaft 211.

[0029] Fly ash and wastewater are fed into the mixing tank 10 through the feed pipe 11 at the top, forming a solid-liquid slurry. Flue gas is fed into the mixing tank 10 from the bottom through the air inlet pipe 12, aerating bubbles in the slurry. The drive motor 21 drives the cutting blades 14 to rotate. The aeration initially forms larger bubbles, which are then cut into smaller bubbles by the cutting blades 14 as they rise, eventually gradually rising and being discharged through the air outlet 13 at the top. By cutting large bubbles into smaller bubbles, not only is the rising speed of the bubbles in the slurry reduced, but they also react more fully with the slurry.

[0030] Specifically, the mixing tank 10 is also equipped with baffles 15. Multiple baffles 15 are arranged vertically and alternately on the inner walls of both sides of the mixing tank 10. The end of each baffle 15 away from the inner wall is inclined downwards, and its end is located below the upper baffle 15. The tortuous channel formed by the multiple baffles 15 increases the path distance for bubbles to rise within the mixing tank 10, thereby further increasing the residence time of the bubbles in the slurry. In this embodiment, the bottom surface of the baffles 15 is provided with multiple sharp teeth arranged in a rectangular array. When a bubble rises to the bottom surface of the baffle 15 and contacts the sharp teeth, it can be punctured to form a smaller bubble.

[0031] Specifically, the drive mechanism 20 also includes gears 22, racks 23 and transmission components. The end of the baffle 15 is hinged to the inner wall of the mixing tank 10, and gears 22 are provided at the hinge. Two racks 23 are respectively arranged on both sides of the mixing tank 10 in a vertical direction and can move up and down, and respectively mesh with multiple gears 22 on both sides. The drive motor 21 is connected to the two racks 23 through the transmission components, and can drive the two racks 23 to move alternately and reciprocally.

[0032] When the drive motor 21 drives the cutting blade 14 to rotate, it can also drive the two racks 23 to move back and forth alternately through the transmission component. When the racks 23 move up and down, they can drive the gear 22 to rotate, thereby driving the baffle 15 to rotate inside the mixing tank 10, lifting it up or rotating it down. The baffle 15 can be lifted up intermittently to prevent air bubbles from getting stuck at the angle between the baffle 15 and the inner wall of the mixing tank 10.

[0033] In this embodiment, the transmission component is a rotating disk 24, which is rotatably mounted at the bottom of the mixing tank 10 and connected to the rotating shaft 211. A groove 241 is circumferentially formed on the outer wall of the rotating disk 24. A slider 231, slidably connected to the groove 241, is provided at the bottom of the rack 23. Most of the groove 241 is horizontally oriented, with a small portion being a downwardly convex arc-shaped section that can drive the rack 23 to move upward. When the rotating disk 24 rotates, the slider 231 of the rack 23 also slides within the groove 241. When the rack rotates to the upwardly convex arc-shaped section of the groove 241, it drives the rack 23 to move downward, and then upward again, thereby causing the rack 23 to drive the baffle 15 to rotate upward and then downward.

[0034] Specifically, the mixing tank 10 is also equipped with multiple spiral blade assemblies 30, which are respectively set at the intervals between multiple baffles 15 and the inner wall of the mixing tank 10. The spiral blade assembly 30 is pushed downward, which can generate a downward thrust on the bubbles, thereby slowing down the rising speed of the bubbles and increasing the residence time of the bubbles in the slurry.

[0035] The helical blade assembly 30 includes a mounting bracket 31, a helical blade 32, a second rotating shaft 33, and an insert rod 34. The mounting bracket 31 is mounted on the inner wall of the mixing tank 10. The second rotating shaft 33 is rotatably mounted on the mounting bracket 31. The lower end of the second rotating shaft 33 is connected to the helical blade 32, and the top end has an insertion hole 331. The inner wall of the insertion hole 331 has a vertical groove 333 and a helical groove 332 circumferentially arranged. The top and bottom ends of the helical groove 332 are respectively connected to the two ends of the vertical groove 333. The bottom of the baffle 15 has a sliding groove 151. One end of the insert rod 34 is slidably inserted into the insertion hole 331, and the end is provided with a slider 341 that can slidably connect with the helical groove 332 and the vertical groove 333. The other end of the insert rod 34 is slidably and rotatably mounted in the sliding groove 151.

[0036] When the baffle 15 rotates, the insert rod 34 is slidably inserted into the insertion hole 331 of the rotating shaft 33. Therefore, the insert rod 34 can only move and rotate axially along the insertion hole 331. The upper end of the insert rod 34 slides and rotates relative to the groove 151, while the lower end moves up and down in the insertion hole 331. The slider 341 at the end also moves in the spiral groove 332 and the vertical groove 333. The spiral groove 332 drives the rotating shaft 33 to rotate on the mounting bracket 31, thereby driving the spiral blade 32 to rotate, generating a downward thrust to slow down the rise of the bubble. The vertical groove 333 allows the slider 341 to slide to the end point of the spiral groove 332 and then slide back to the starting point, thus preventing the rotating shaft 33 from rotating and avoiding the spiral blade 32 from reversing and generating suction.

[0037] In this embodiment, to ensure that slider 2 341 does not move back within the spiral groove 332, grooved steps can be provided at the connection points of the spiral groove and the vertical groove at both ends, and slider 2 is made of elastic material. When slider 2 slides to the end of the spiral groove, it falls into the step at point A, preventing it from moving back. Subsequently, the depth of the vertical groove gradually decreases until it reaches the beginning of the spiral groove, where slider 2 falls into the step at point B again. Similarly, the depth of the spiral groove gradually decreases from top to bottom.

[0038] In addition, the bottom of the mixing tank 10 is equipped with a discharge pipe 16, and both the feed pipe 11 and the discharge pipe 16 are equipped with branch pipes, which are connected to the suction pump 17. The discharge pipe 16 is used to discharge the slurry after the device is used up. The feed pipe 11 and the discharge pipe 16 are connected to the suction pump 17 through the branch pipes, which can circulate the slurry during use, which can not only improve the fluidity of the slurry, but also improve the uniformity of the slurry.

[0039] The working principle of the above-mentioned gas-liquid-solid three-phase mixing system for fly ash carbonation reaction is as follows: Fly ash and wastewater are input through the feed pipe 11 at the top of the mixing tank 10 to form a solid-liquid slurry. Flue gas is input from the bottom of the mixing tank 10 through the air inlet pipe 12, and bubbles are aerated in the slurry. The drive motor 21 drives the cutting blades 14 and the rotating disk 24 to rotate. The cutting blades 14 can cut large bubbles into smaller bubbles. The rotating disk 24 drives the rack 23 to move up and down reciprocally through the cooperation of the sliding groove 241 and the slider 231, driving the baffles 15 on both sides to rotate alternately upwards, so that the bubbles gradually rise in the tortuous channel. While the baffles 15 are rotating, they can also drive the spiral blades 32 to rotate, generating a downward thrust on the bubbles, thereby slowing down the rise of the bubbles. The bubbles finally rise to the exhaust port at the top and are discharged.

[0040] Using the aforementioned gas-liquid-solid three-phase mixing system for fly ash carbonation reaction, the rising velocity of bubbles is reduced by cutting and puncturing them into smaller bubbles, allowing for more complete reaction with the slurry. Furthermore, the folded channels formed by the baffles increase the rising path and residence time of the bubbles, further enhancing the reaction time between CO2 and fly ash.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction, characterized in that: It includes a mixing tank and a drive mechanism; the mixing tank is provided with a feed pipe at the top, an air inlet pipe at the bottom, an air outlet at the top, and a cutting blade at the bottom; the drive mechanism includes a drive motor, which is mounted on the mixing tank and connected to the cutting blade via a rotating shaft.

2. The gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to claim 1, characterized in that: The mixing tank is also equipped with baffles. Multiple baffles are arranged sequentially and alternately on the inner walls of both sides of the mixing tank in a vertical direction. The end of the baffle away from the inner wall of the mixing tank is inclined downward and the end is located below the upper baffle.

3. A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to claim 2, characterized in that: The bottom surface of the baffle is provided with sharp teeth arranged in a rectangular array.

4. A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to claim 2, characterized in that: The baffle is hinged to the inner wall of the mixing tank, and the baffles on both sides can rotate upward alternately.

5. A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to claim 4, characterized in that: The drive mechanism also includes gears, racks and transmission components. Gears are provided at the hinge of the baffle and the mixing tank. The two racks are vertically and movably arranged on both sides of the mixing tank and mesh with multiple gears on both sides respectively. The drive motor is connected to the two racks through the transmission components and can drive the two racks to move alternately and reciprocally.

6. A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to claim 5, characterized in that: The transmission component includes a rotating disk, which is rotatably disposed at the bottom of the mixing tank and connected to a rotating shaft. The rotating disk has a circumferential groove, and the bottom of the rack has a slider that is slidably connected to the groove. The groove has a downwardly convex arc section that can drive the rack to move upward.

7. A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to claim 5, characterized in that: The mixing tank is also equipped with multiple helical blade assemblies, which are respectively arranged in the gaps between multiple baffles and the inner wall of the mixing tank, and the propulsion direction of the helical blade assemblies is downward.

8. A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to claim 7, characterized in that: The spiral blade assembly includes a mounting bracket, spiral blades, a second rotating shaft, and an insert rod. The mounting bracket is disposed on the inner wall of the mixing tank. The second rotating shaft is rotatably mounted on the mounting bracket. The spiral blades are disposed on the second rotating shaft. The top end of the second rotating shaft has an insertion hole. The insertion hole has a vertical groove and a spiral groove. The top and bottom ends of the spiral groove are respectively connected to the two ends of the vertical groove. The bottom of the baffle has a second sliding groove. One end of the insert rod is slidably inserted into the insertion hole, and the end of the rod has a second sliding block that can slidably connect with the spiral groove and the vertical groove. The other end of the insert rod is slidably and rotatably disposed in the second sliding groove.

9. A gas-liquid-solid three-phase mixing system for fly ash carbonation reaction according to claim 1, characterized in that: The bottom of the mixing tank is also provided with a discharge pipe, and both the inlet pipe and the discharge pipe are provided with branch pipes, which are connected to the suction pump through the branch pipes.

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