A method for scale inhibition using microbubbles in the production process of wet-process phosphoric acid

Abstract

The present invention provides a method for preventing scale formation by using microbubbles in the production process of wet-process phosphoric acid. By introducing microbubbles during the slurry transportation process, a layer of microbubble "protective film" is adsorbed and aggregated on the surface of the pipe wall or the scale deposits, preventing the deposition of scale-forming substances on the pipe wall or continuous scale formation. At the same time, the surface of the microbubbles is negatively charged, which can enrich impurity ions in the liquid phase on the surface of the microbubbles, avoiding the formation of poorly soluble precipitates and resulting in scale formation. In addition, the multiphase fluid formed by the uniform mixing of the slurry and the microbubbles can peel off the solids deposited on the pipe wall, pipe elbows or pipe diameter changes, realizing pipe descaling in the production process of wet-process phosphoric acid and avoiding pipe blockage.

Description

Technical Field

[0001] The present invention belongs to the technical field of wet-process phosphoric acid, and particularly relates to a method for preventing scale by using microbubbles in the production process of wet-process phosphoric acid. Background Art

[0002] In the production process of wet-process phosphoric acid, apatite reacts with sulfuric acid to generate phosphoric acid and phosphogypsum continuously. The phosphogypsum crystals grow continuously, and are prone to crystallize, grow and scale on the pipe wall, pipe elbow or pipe diameter change, affecting the normal fluid transportation of the pipeline; in addition, a large amount of impurities such as carbon, silicon, aluminum, iron, and magnesium are contained in apatite, which are dissolved and released into phosphoric acid during the acidolysis process, and are prone to combine with calcium ions, potassium ions, sodium ions or fluoride ions, etc., and may co-precipitate with phosphogypsum to form insoluble solids, thereby scaling inside the pipeline or reactor, affecting the normal transportation of the pipeline or the normal operation of the reactor.

[0003] CN106882776A discloses a wet-process phosphoric acid production system and a wet-process phosphoric acid production method. The wet-process phosphoric acid production system includes a mineral material conveying device, a slurry storage tank, a slurry thickening tank, a slurry high-level tank, an extraction tank, a slurry thickening tank, a phosphoric acid clarification tank, and a phosphoric acid storage tank which are connected in sequence. By connecting the thick slurry discharge port of the slurry thickening tank to the feed port of the thick slurry dilution tank, the filtration and cleaning equipment does not participate in the filtration of the original phosphoric acid solution, and only filters the diluted slurry separated by the slurry thickener, to solve the problem of scaling and blockage of the filter and related pipelines. The above wet-process phosphoric acid production system has a poor effect on treating pipeline scaling, the filter needs to be repaired frequently, and the production cost is relatively high.

[0004] CN210973888U discloses a wet-process phosphoric acid production system, which uses the recycled phosphoric acid as the washing water in the three-washing area, and uses clean and high-temperature condensed water as the filter cloth regeneration water in the filter cloth regeneration area. By adding concentrated sulfuric acid to the three-washing liquid storage tank, the scale-forming substances can be settled and then quickly washed down in the three-washing area. Adding sulfuric acid can improve the washing effect. The above production system has a complex structure and a relatively high production cost of phosphoric acid.

[0005] Therefore, it is necessary to provide a method for preventing scale by using microbubbles in the production process of wet-process phosphoric acid, which has a simple method, a relatively low production cost of phosphoric acid, and can effectively avoid the crystallization and growth of phosphogypsum and scale-forming substances in the wet-process phosphoric acid process, and avoid pipeline descaling and blockage. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preventing scale by using microbubbles in the production process of wet-process phosphoric acid. By introducing microbubbles during the slurry transportation process, it is possible to avoid the deposition or continuous scaling of scale-forming substances on the pipe wall, and at the same time, utilize the negative charge carried on the surface of the microbubbles to enrich the impurity ions in the liquid phase, avoid the formation of insoluble precipitates and cause scaling, realize pipeline descaling, and avoid pipeline blockage.

[0007] To achieve the object of the present invention, the following technical solutions are adopted in the present invention:

[0008] The object of the present invention is to provide a method for scale inhibition by microbubbles in the production process of wet-process phosphoric acid. The method includes: introducing microbubbles into the pipeline for transporting pulp used in the production of wet-process phosphoric acid to obtain pulp containing microbubbles, thereby achieving scale inhibition.

[0009] In the method for scale inhibition by microbubbles in the production process of wet-process phosphoric acid provided by the present invention, the microbubbles are introduced into the pulp transportation process. The microbubbles can adsorb and aggregate on the pipe wall or the surface of the scale deposits, thereby forming a "protective film" to prevent the scale-forming substances from depositing on the pipe wall or continuously forming scale; at the same time, the surface of the microbubbles is negatively charged, which can adsorb impurity ions such as calcium, potassium, sodium, aluminum, iron, and magnesium in the liquid phase, enriching them on the surface of the microbubbles and reducing their concentration in the liquid phase, thereby avoiding the formation of insoluble precipitates and causing scale; in addition, the uniform mixing of the pulp and the microbubbles can form a multiphase fluid with strong shear force, which is beneficial to the peeling of solids deposited on the pipe wall, pipe elbows or pipe diameter changes, realizing pipe descaling and avoiding pipe blockage. The method of the present invention is simple to operate, has good pipe descaling effect, and is suitable for large-scale popularization and application.

[0010] The present invention cannot use millimeter-sized large bubbles for pipe descaling because the millimeter-sized large bubbles are extremely easy to polymerize in the pipeline to form a large-scale gas mass, that is, a continuous phase of gas is formed in the pulp, which is difficult to form a multiphase fluid with strong shear force, is not conducive to the stable transportation of the fluid, and will cause serious cavitation to the delivery pump.

[0011] Preferably, the method of introducing microbubbles is to insert a bubble gun into the pipeline for transporting pulp, and the microbubbles are ejected by the bubble gun.

[0012] Preferably, the bubble gun includes a high-pressure gas microporous bubble gun or a high-pressure gas membrane bubble gun.

[0013] Preferably, the pressure of the high-pressure gas microporous bubble gun and the high-pressure gas membrane bubble gun is 0.4 - 0.8 MPa, for example, it can be 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa or 0.8 MPa, etc.

[0014] Preferably, the time for the microbubbles to travel from the position where the bubble gun is inserted to the scale-prone pipe section of the pipeline for transporting pulp is 0.5 s - 15 s, for example, it can be 0.5 s, 1 s, 3 s, 5 s, 10 s, 13 s or 15 s, etc.

[0015] Preferably, the position where the bubble gun releases microbubbles is at the top of the bubble gun.

[0016] Preferably, the nozzles of the bubble gun are evenly distributed in a ring shape in the pulp conveying pipeline. This can not only enable microbubbles to adsorb and accumulate on the pipe wall, avoiding the deposition or continuous scaling of scale-forming substances on the pipe wall, but also effectively adsorb impurity ions in the liquid phase inside the pipeline. Moreover, the microbubbles sprayed by the nozzles evenly distributed in a ring shape are more evenly mixed with the pulp, which is beneficial to the peeling off of solids deposited on the pipe wall, pipe elbows or pipe diameter changes, achieving efficient pipe descaling.

[0017] Preferably, the distance between the nozzles distributed on the outer ring and the center point of the pulp conveying pipeline is 3 / 4 to 2 / 3 of the radius of the pulp conveying pipeline. For example, it can be 3 / 4, 37 / 50, 7 / 10, 17 / 25 or 2 / 3, etc.

[0018] The present invention preferably sets the distance between the nozzles distributed on the outer ring and the center point of the pulp conveying pipeline to be 3 / 4 to 2 / 3 of the radius of the pulp conveying pipeline. This can not only reduce the deposition of scale-forming substances on the pipe wall, but also effectively adsorb impurity ions in the liquid phase inside the pipeline, thereby reducing the thickness of the solids finally deposited on the wall of the pulp conveying pipeline.

[0019] Preferably, the distance between the nozzles distributed on the inner ring and the center point of the pulp conveying pipeline is 1 / 3 to 1 / 2 of the radius of the pulp conveying pipeline. For example, it can be 1 / 3, 7 / 20, 19 / 50, 2 / 5 or 3 / 4, etc.

[0020] Preferably, the nozzles on the outer ring and the nozzles on the inner ring are staggered, which is beneficial to the more uniform mixing of microbubbles and pulp.

[0021] Preferably, the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp is 1:(12 - 80). For example, it can be 1:12, 1:20, 1:30, 1:50, 1:70 or 1:80, etc.

[0022] The present invention preferably sets the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp to be 1:(12 - 80), which can greatly reduce the thickness of the solids finally deposited on the wall of the pulp conveying pipeline. When the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp is small, that is, the amount of microbubbles is small, it is not possible to form a microbubble "protective film" on the pipe wall or the surface of the scale well, and a multiphase fluid with strong shear force cannot be formed after the microbubbles are mixed with the pulp, so the solids deposited on the pipe wall, pipe elbows or pipe diameter changes cannot be effectively peeled off; when the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp is large, that is, the amount of microbubbles is large, a multiphase fluid with strong shear force cannot be formed after the microbubbles are mixed with the pulp either, and the effect of removing solids deposited on the pipe wall, pipe elbows or pipe diameter changes is poor.

[0023] Preferably, the diameter of the microbubbles is 1 to 500 μm, for example, it can be 1 μm, 10 μm, 50 μm, 100 μm, 300 μm, 400 μm, 500 μm, etc.

[0024] Preferably, the gas in the microbubbles includes any one or a combination of at least two of air, nitrogen, helium or argon. Among them, typical but non-limiting combinations include the combination of air and nitrogen, the combination of helium and argon, or the combination of nitrogen and helium.

[0025] The numerical ranges described in the present invention not only include the point values exemplified above, but also include any point values between the above numerical ranges not exemplified. Due to space limitations and for the sake of brevity, the specific point values included in the ranges of the present invention are not exhaustively listed herein.

[0026] As a preferred technical solution of the present invention, the method includes: during the production process of wet-process phosphoric acid, inserting a high-pressure gas microporous bubbling gun or a high-pressure gas membrane bubbling gun with a pressure of 0.4 to 0.8 MPa into the slurry conveying pipeline, introducing microbubbles with a diameter of 1 to 500 μm, obtaining slurry containing microbubbles, and achieving scale inhibition;

[0027] The time for the microbubbles to travel from the position where the bubbling gun is inserted to the easily fouling pipe section of the slurry conveying pipeline is 0.5 s to 15 s; the position where the bubbling gun releases microbubbles is at the top, and the gun heads of the bubbling gun are evenly distributed in a ring shape in the slurry conveying pipeline; the distance between the gun heads distributed on the outer ring and the center point of the slurry conveying pipeline is 3 / 4 to 2 / 3 of the radius of the slurry conveying pipeline; the distance between the gun heads distributed on the inner ring and the center point of the slurry conveying pipeline is 1 / 3 to 1 / 2 of the radius of the slurry conveying pipeline; the gun heads of the outer ring and the inner ring are staggered; the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the slurry is 1:(12 - 80); the gas in the microbubbles includes any one or a combination of at least two of air, nitrogen, helium or argon.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention uses microbubbles to strengthen the scale removal of the slurry conveying pipeline in the wet-process phosphoric acid production process. By introducing microbubbles during the slurry transportation process, the deposition or scaling on the pipe wall is avoided, and the solids deposited on the pipe wall, pipe elbows or pipe diameter changes are strengthened and peeled off, realizing pipeline scale removal and scale inhibition, and avoiding pipeline blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a cross-sectional schematic view of the slurry conveying pipeline with a bubbling gun inserted therein according to the present invention.

[0031] In the figure: 1 - slurry conveying pipeline; 2 - bubbling gun; 3 - gun head of the inner ring bubbling gun; 4 - gun head of the outer ring bubbling gun. Specific Embodiments

[0032] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] The present invention will be further described in detail below. However, the following examples are merely simple examples of the present invention and do not represent or limit the scope of the claimed protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0034] As Figure 1 shown, the present invention provides a method for scale inhibition by microbubbles in the production process of wet-process phosphoric acid. Specifically, the method includes: during the production process of wet-process phosphoric acid, inserting a high-pressure gas microporous bubbling gun or a high-pressure gas membrane bubbling gun with a pressure of 0.4 - 0.8 MPa into the slurry conveying pipeline, introducing microbubbles with a diameter of 1 - 500 μm, obtaining slurry containing microbubbles, and achieving scale inhibition;

[0035] The time for the microbubbles to travel from the position where the bubbling gun is inserted to the easily fouled pipe section of the slurry conveying pipeline is 0.5 s - 15 s; the position where the bubbling gun releases microbubbles is at the top, and the gun heads of the bubbling gun are evenly distributed in a ring shape in the slurry conveying pipeline; the distance from the gun heads distributed in the outer ring to the center point of the slurry conveying pipeline is 3 / 4 - 2 / 3 of the radius of the slurry conveying pipeline; the distance from the gun heads distributed in the inner ring to the center point of the slurry conveying pipeline is 1 / 3 - 1 / 2 of the radius of the slurry conveying pipeline; the gun heads of the outer ring and the inner ring are staggered; the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the slurry is 1:(12 - 80); the gas in the microbubbles includes any one or a combination of at least two of air, nitrogen, helium, or argon.

[0036] Example 1

[0037] This example provides a method for scale inhibition by microbubbles in the production process of wet-process phosphoric acid. The method includes: during the production process of wet-process phosphoric acid, inserting a high-pressure gas microporous bubbling gun or a high-pressure gas membrane bubbling gun with a pressure of 0.4 MPa into the slurry conveying pipeline, introducing microbubbles with a diameter of 1 - 200 μm, obtaining slurry containing microbubbles, and achieving scale inhibition;

[0038] The time for the microbubbles to travel from the position where the bubbling gun is inserted to the fouling-prone pipe section of the pulp conveying pipeline is 6 s; the position where the bubbling gun releases the microbubbles is at the top, and the gun heads of the bubbling gun are evenly distributed in a ring shape in the pulp conveying pipeline; the distance from the gun heads distributed in the outer ring to the center point of the pulp conveying pipeline is 3 / 4 of the radius of the pulp conveying pipeline; the distance from the gun heads distributed in the inner ring to the center point of the pulp conveying pipeline is 1 / 2 of the radius of the pulp conveying pipeline; the gun heads in the outer ring and the inner ring are staggered; the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp is 1:30; the gas in the microbubbles is air.

[0039] Example 2

[0040] This example provides a method for preventing fouling by using microbubbles during the production of wet-process phosphoric acid. The method includes: during the production of wet-process phosphoric acid, inserting a high-pressure gas microporous bubbling gun or a high-pressure gas membrane bubbling gun with a pressure of 0.8 MPa into the pulp conveying pipeline, introducing microbubbles with a diameter of 1 - 500 μm, obtaining pulp containing microbubbles, and achieving fouling prevention.

[0041] The time for the microbubbles to travel from the position where the bubbling gun is inserted to the fouling-prone pipe section of the pulp conveying pipeline is 0.5 s; the position where the bubbling gun releases the microbubbles is at the top, and the gun heads of the bubbling gun are evenly distributed in a ring shape in the pulp conveying pipeline; the distance from the gun heads distributed in the outer ring to the center point of the pulp conveying pipeline is 2 / 3 of the radius of the pulp conveying pipeline; the distance from the gun heads distributed in the inner ring to the center point of the pulp conveying pipeline is 1 / 3 of the radius of the pulp conveying pipeline; the gun heads in the outer ring and the inner ring are staggered; the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp is 1:12; the gas in the microbubbles is nitrogen.

[0042] Example 3

[0043] This example provides a method for preventing fouling by using microbubbles during the production of wet-process phosphoric acid. The method includes: during the production of wet-process phosphoric acid, inserting a high-pressure gas microporous bubbling gun or a high-pressure gas membrane bubbling gun with a pressure of 0.5 MPa into the pulp conveying pipeline, introducing microbubbles with a diameter of 1 - 300 μm, obtaining pulp containing microbubbles, and achieving fouling prevention.

[0044] The time for the microbubbles to travel from the position where the bubbling gun is inserted to the fouling-prone pipe section of the pulp conveying pipeline is 15 s; the position where the bubbling gun releases the microbubbles is at the top, and the gun heads of the bubbling gun are evenly distributed in a ring shape in the pulp conveying pipeline; the distance from the gun heads distributed in the outer ring to the center point of the pulp conveying pipeline is 3 / 4 of the radius of the pulp conveying pipeline; the distance from the gun heads distributed in the inner ring to the center point of the pulp conveying pipeline is 1 / 3 of the radius of the pulp conveying pipeline; the gun heads in the outer ring and the inner ring are staggered; the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp is 1:80; the gas in the microbubbles is a mixture of 50% helium and 50% argon.

[0045] Example 4

[0046] This example provides a method for preventing fouling by microbubbles during the production of wet-process phosphoric acid. Except that the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp is 1:5, other conditions are the same as those in Example 1.

[0047] Example 5

[0048] This example provides a method for preventing fouling by microbubbles during the production of wet-process phosphoric acid. Except that the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the pulp is 1:120, other conditions are the same as those in Example 1.

[0049] Example 6

[0050] This example provides a method for preventing fouling by microbubbles during the production of wet-process phosphoric acid. Except that the gun heads distributed in the outer ring are deleted, and only the gun heads distributed in the inner ring are evenly distributed in a circle in the pulp conveying pipeline, other conditions are the same as those in Example 1.

[0051] Example 7

[0052] This example provides a method for preventing fouling by microbubbles during the production of wet-process phosphoric acid. Except that the distance from the gun heads distributed in the outer ring to the center point of the pulp conveying pipeline is 3 / 5 of the radius of the pulp conveying pipeline, other conditions are the same as those in Example 1.

[0053] Example 8

[0054] This example provides a method for preventing fouling by microbubbles during the production of wet-process phosphoric acid. Except that the distance from the gun heads distributed in the outer ring to the center point of the pulp conveying pipeline is 9 / 10 of the radius of the pulp conveying pipeline, other conditions are the same as those in Example 1.

[0055] Comparative Example 1

[0056] This comparative example provides a method for preventing scale in the production process of wet-process phosphoric acid. Except for introducing bubbles with a diameter of 1 - 50 mm with the same gas volume, other conditions are the same as those in Example 1.

[0057] The results of the solid thickness deposited on the wall of the slurry conveying pipeline in the above-mentioned examples and comparative examples are listed in Table 1.

[0058] Table 1

[0059]

[0060]

[0061] It can be seen from Table 1 as follows:

[0062] (1) From Examples 1 - 3, it can be seen that the method for preventing scale by using microbubbles in the production process of wet-process phosphoric acid provided by the present invention can effectively avoid the deposition or scaling on the pipe wall, strengthen the peeling of solids deposited on the pipe wall, pipe elbows or pipe diameter changes, and finally the solid thickness deposited on the wall of the slurry conveying pipeline is small.

[0063] (2) From Examples 1 and 4 - 5, it can be seen that in Example 4, the ratio of the total gas flow rate required for microbubbles to the volume flow rate of the slurry is 1:5, and the amount of microbubbles is large. After the microbubbles are mixed with the slurry, a multiphase fluid with strong shear force cannot be formed, and the effect of removing solids deposited on the pipe wall, pipe elbows or pipe diameter changes is poor. Finally, the solid thickness deposited on the wall of the slurry conveying pipeline is 1.55 cm. In Example 5, the ratio of the total gas flow rate required for microbubbles to the volume flow rate of the slurry is 1:120, and the amount of microbubbles is small. A microbubble "protective film" cannot be well formed on the pipe wall or the surface of the scale deposit, and a multiphase fluid with strong shear force cannot be formed after the microbubbles are mixed with the slurry. Finally, the solid thickness deposited on the wall of the slurry conveying pipeline is 1.46 cm.

[0064] (3) From Examples 1 and 6 - 8, it can be seen that in Example 6, only the lance heads distributed in the inner ring are evenly distributed in a circle in the slurry conveying pipeline. In Example 7, the distance between the lance heads distributed in the outer ring and the center point of the slurry conveying pipeline is 3 / 5 of the radius of the slurry conveying pipeline. In Example 8, the distance between the lance heads distributed in the outer ring and the center point of the slurry conveying pipeline is 9 / 10 of the radius of the slurry conveying pipeline. The scale prevention effect on the slurry conveying pipeline is poor, and the solid thickness finally deposited on the wall of the slurry conveying pipeline is large.

[0065] (5) It can be seen from the comprehensive implementation example 1 and comparative example 1 that in comparative example 1, bubbles with a diameter of 1-50 mm and the same gas volume were introduced. Since the large millimeter-sized bubbles are extremely easy to aggregate in the pipeline to form a large-scale gas mass, that is, a continuous phase of gas is formed in the pulp, it is difficult to form a multiphase fluid with strong shear force. Finally, the solid thickness deposited on the wall of the pulp conveying pipeline is 5.66 cm. Moreover, the introduction of large millimeter-sized bubbles is not conducive to the stable transportation of the fluid, and it will cause serious cavitation to the conveying pump.

[0066] In summary, the method for preventing scale by using microbubbles in the wet-process phosphoric acid production process provided by the present invention introduces microbubbles during the pulp transportation process, avoids the deposition or scaling on the pipe wall, strengthens the peeling of solids deposited on the pipe wall, pipe elbows or variable diameters, realizes pipe descaling and scale prevention, and avoids pipe blockage, and is suitable for large-scale popularization and application.

[0067] The applicant declares that the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for scale inhibition using microbubbles in the wet-process phosphoric acid production process, characterized in that The method includes: introducing microbubbles into the slurry pipeline for wet-process phosphoric acid production to obtain slurry containing microbubbles and achieve scale inhibition; the way of introducing microbubbles is to insert a bubbling gun into the slurry pipeline, and the microbubbles are ejected by the bubbling gun. The tips of the bubbling gun are evenly distributed in a ring in the slurry pipeline. The distance from the tips of the outer ring to the center point of the slurry pipeline is 3 / 4 to 2 / 3 of the radius of the slurry pipeline. The distance from the tips of the inner ring to the center point of the slurry pipeline is 1 / 3 to 1 / 2 of the radius of the slurry pipeline. The ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the slurry is 1:(12 - 80). The diameter of the microbubbles is 1 to 500 μm.

2. The method according to claim 1, characterized in that The bubbling gun includes a high-pressure gas microporous bubbling gun or a high-pressure gas membrane bubbling gun.

3. The method according to claim 2, characterized in that, The pressure of the high-pressure gas microporous bubbling gun and the high-pressure gas membrane bubbling gun is 0.4 to 0.8 MPa.

4. The method according to claim 1, wherein The time for the microbubbles to reach the easily fouled pipe section of the slurry pipeline from the position where the bubbling gun is inserted is 0.5 s to 15 s.

5. The method according to claim 1, wherein The position where the bubbling gun releases microbubbles is at the top of the bubbling gun.

6. The method according to claim 1, characterized in that, The tips of the outer ring and the inner ring are staggered.

7. The method according to claim 1, characterized in that, The gas in the microbubbles includes any one or a combination of at least two of air, nitrogen, helium or argon.

8. The method according to claim 1, characterized in that, The method includes: during the wet-process phosphoric acid production process, inserting a high-pressure gas microporous bubbling gun or a high-pressure gas membrane bubbling gun with a pressure of 0.4 to 0.8 MPa into the slurry pipeline, introducing microbubbles with a diameter of 1 to 500 μm to obtain slurry containing microbubbles and achieve scale inhibition. The time for the microbubbles to reach the easily fouled pipe section of the slurry pipeline from the position where the bubbling gun is inserted is 0.5 s to 15 s; the position where the bubbling gun releases microbubbles is at the top, and the tips of the bubbling gun are evenly distributed in a ring in the slurry pipeline; the distance from the tips of the outer ring to the center point of the slurry pipeline is 3 / 4 to 2 / 3 of the radius of the slurry pipeline; the distance from the tips of the inner ring to the center point of the slurry pipeline is 1 / 3 to 1 / 2 of the radius of the slurry pipeline; the tips of the outer ring and the inner ring are staggered; the ratio of the total gas flow rate required for the microbubbles to the volume flow rate of the slurry is 1:(12 - 80); the gas in the microbubbles includes any one or a combination of at least two of air, nitrogen, helium or argon.

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