A fluidized bed catalytic softening system with online seed crystal regeneration function

Abstract

This invention provides a fluidized bed catalytic softening system with online seed activity regeneration, belonging to the field of mine water treatment. It addresses the problem of seed activity gradually declining over time, requiring frequent replenishment of fresh seeds. The system includes a fluidized bed crystallization softening tower, an inlet module, a pH adjustment module, a grain classification bed, and a seed activity regeneration module. The fluidized bed crystallization softening tower has an inlet and a seed outlet at the bottom, and a softened water outlet and a seed replenishment port at the top. The inlet module includes an inlet pipe and a cyclone feeder. The grain classification bed is located inside the fluidized bed crystallization softening tower for seed size classification. The seed activity regeneration module monitors the surface activity of the seeds in real time and performs multi-frequency synergistic cleaning. This system achieves online recovery of seed surface activity, instantaneous uniform mixing of inlet water and reagents, and automatic grain classification and circulation, extending seed lifespan and improving system operational stability.

Description

Technical Field

[0001] This invention belongs to the field of mine water treatment, and in particular relates to a fluidized bed catalytic softening system with online seed crystal activity regeneration function. Background Technology

[0002] High-salinity mine water generated during coal mining typically contains high concentrations of calcium and magnesium ions, with a total hardness (calculated as CaCO3) often ranging from 400 to 1000 mg / L. This type of high-hardness wastewater readily forms calcium carbonate scale during subsequent membrane concentration or evaporation crystallization processes, leading to reduced heat exchange efficiency, equipment blockage, and frequent shutdowns for cleaning. This severely restricts the economic viability and operational stability of zero-discharge technology for high-salinity wastewater.

[0003] Currently, the most mature method for hardness removal in wastewater is chemical precipitation, which involves pretreatment with sodium hydroxide or lime to precipitate calcium ions as calcium carbonate. However, this method requires large amounts of alkaline reagents, and the resulting fine crystals have poor settling properties, affecting the pH and turbidity of the effluent. In contrast, catalytic softening crystallization, based on the addition of specific seed crystals, utilizes the surface characteristics of the seed crystals to induce heterogeneous nucleation and growth of CaCO3, generating larger, uniform, and easily settling calcium carbonate crystals. This method is simple and efficient, and the products have the potential for resource utilization. For example, patent CN117088481A discloses an induced crystallization granulation fluidized bed device, which uses a flow-collecting mixing hood and a reflective sedimentation agitator to achieve the reuse of crystal nuclei and improve the crystallization granulation effect; patents CN118047497A and CN118047498A respectively disclose an induced crystallization circulating crystallization granulation fluidized bed and its system, which realizes the hardness adjustment of seawater desalination water by coupling crystallization granulation and mineralization technologies; patent CN120794201A discloses an induced crystallization granulation fluidized bed softening water treatment module, which uses synchronous multi-dimensional excitation to enhance crystal fluidization and solves the problem of local reaction dead zones.

[0004] However, in existing modules and methods, the activity of the seed crystals gradually decreases with the extension of the running time, and fresh seed crystals need to be replenished frequently. Specifically, during long-term operation, the surface of the seed crystals is gradually covered by reaction products, the number of active sites decreases, the ability to induce crystallization decreases, and the softening efficiency is reduced. In order to ensure the treatment effect, it is necessary to continuously replenish fresh seed crystals, which increases the operating cost and operational complexity. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a fluidized bed catalytic softening system with online seed activity regeneration function, which solves the problem that the seed activity gradually decreases with the extension of the operating time in the prior art, requiring frequent replenishment of fresh seed crystals.

[0006] To achieve the above and other related objectives, this invention provides a fluidized bed catalytic softening system with online seed crystal activity regeneration function, comprising: a fluidized bed crystallization softening tower, wherein a raw water inlet and a seed crystal outlet are provided at the bottom of the fluidized bed crystallization softening tower, and a softened water outlet and a seed crystal replenishment outlet are provided at the top, with the seed crystal outlet located below the raw water inlet; a water inlet module, comprising a water inlet pipe and a cyclone feeder, wherein the first end of the water inlet pipe passes through the raw water inlet and is located inside the fluidized bed crystallization softening tower, and the cyclone feeder is connected to the water inlet pipe for mixing the raw water, reagents, and returned small-particle seed crystals entering the tower; and a pH adjustment module, connected to the water inlet pipe for adjusting the pH of the water entering the fluidized bed crystallization softening tower. The pH value is adjusted; a grain classification bed is set inside the fluidized bed crystallization softening tower, above the cyclone feeder and below the softened water outlet and seed inlet, for classifying the seed crystals by particle size; a seed activity regeneration module is set inside the fluidized bed crystallization softening tower for online cleaning of the seed crystals to restore their surface activity; the seed activity regeneration module includes an ultrasonic-microbubble synergistic cleaning module, a seed crystal surface state monitoring module, and a broadband excitation module; the seed crystal surface state monitoring module is used to monitor the surface activity state of the seed crystals in real time, and when a decrease in seed crystal activity is detected, the broadband excitation module and the ultrasonic-microbubble synergistic cleaning module perform multi-frequency synergistic cleaning of the seed crystals.

[0007] Optionally, the grain-grading bed includes a wedge-shaped wire mesh assembly, a support frame, and a collecting cone; the support frame includes an upper support ring and a lower support ring, which are connected to the inner wall of the fluidized bed crystallization softening tower; the wedge-shaped wire mesh assembly is disposed between the upper and lower support rings; the wedge-shaped wire mesh assembly includes multiple layers of wedge-shaped wire mesh, with the mesh openings of adjacent layers of wedge-shaped wire mesh staggered; the collecting cone is connected to the inner wall of the fluidized bed crystallization softening tower and is located between the lower support ring and the cyclone feeder; a reflux channel is formed between the collecting cone and the inner wall of the fluidized bed crystallization softening tower; the diameter of the collecting cone gradually increases from the end near the cyclone feeder to the end near the lower support ring.

[0008] Optionally, the ultrasonic-microbubble synergistic cleaning module includes a microbubble generator and multiple ultrasonic transducers, with the outlet of the microbubble generator located above the grain classification bed; and the multiple ultrasonic transducers arranged in an array below the grain classification bed.

[0009] Optionally, the seed crystal surface state monitoring module includes an electrochemical impedance sensor and / or a laser particle size analyzer, which are positioned above the grain classification bed; and / or, the broadband excitation module includes a mounting frame, multiple annular electromagnets, a piezoelectric ceramic stack, and an elastic support frame; both ends of the mounting frame are connected to the inner wall of the fluidized bed crystallization softening tower, and the multiple annular electromagnets are spaced apart on the mounting frame; the piezoelectric ceramic stack is positioned on the elastic support frame, which is positioned on the inner wall of the fluidized bed crystallization softening tower.

[0010] Optionally, it also includes an acid adjustment module. The fluidized bed crystallization softening tower also includes an acid adjustment outlet and an acid adjustment inlet. The acid adjustment inlet is located between the acid adjustment outlet and the softened water outlet. The acid adjustment outlet is located above the seed crystal activity regeneration module. The acid adjustment module is connected to the acid adjustment inlet, the acid adjustment outlet and the external system. The acid adjustment module is used to draw water out of the fluidized bed crystallization softening tower through the acid adjustment outlet and treat it with carbon dioxide in the industrial flue gas introduced into the external system before discharging it back into the fluidized bed crystallization softening tower through the acid adjustment inlet.

[0011] Optionally, the acid-adjusting module includes a first circulating pump, a first dissolved gas tank, a gas releaser, a first pipeline, a second pipeline, and an intermediate water tank; the first circulating pump is connected to the first dissolved gas tank and the acid-adjusting outlet, and the first dissolved gas tank is also connected to an external system; the gas releaser is installed in the intermediate water tank, and the gas releaser is connected to the first dissolved gas tank through the first pipeline, and the intermediate water tank is also connected to the acid-adjusting inlet through the second pipeline.

[0012] Optionally, the acid adjustment module also includes a first switching valve; the first switching valve is located on the second pipeline; the microbubble generator includes a second circulating pump, a second dissolved air tank, a second switching valve, and a third pipeline; the second circulating pump is connected to the softened water outlet and the second dissolved air tank, and the second dissolved air tank is connected to the external atmosphere; the second dissolved air tank is also connected to a gas release device through a pipeline, and the third pipeline is connected to the intermediate water tank and the fluidized bed crystallization softening tower; the second switching valve is located on the third pipeline.

[0013] Optionally, the cyclone feeder includes a venturi tube and a cyclone blade assembly; the venturi tube is connected to the second end of the inlet pipe, and the cyclone blade assembly is connected to the first end of the inlet pipe; the venturi tube has a constriction section, a throat, and a diffuser section, and the throat is provided with an alkali inlet; the pH adjustment module includes a second online pH meter, a metering pump, and an alkali storage tank; the second online pH meter is connected to the inlet pipe; one end of the metering pump is connected to the alkali inlet of the venturi tube, and the other end is connected to the alkali storage tank.

[0014] Optionally, it also includes a seed crystal recovery module, which is connected to the seed crystal discharge port and seed crystal inlet of the fluidized bed crystallization softening tower. The seed crystal recovery module is used to separate the seed crystal slurry discharged from the fluidized bed crystallization softening tower, so that the separated fine seed crystals are returned to the seed crystal replenishment port for reuse, and the separated large particle crystals are recovered as by-products.

[0015] Optionally, the seed crystal recovery module includes a hydrocyclone separator, a crystal particle collection tank, and a seed crystal reuse pipe. The hydrocyclone separator is connected to the seed crystal discharge outlet, its underflow outlet is connected to the crystal particle collection tank, and its overflow outlet is connected to the seed crystal inlet through the seed crystal reuse pipe.

[0016] As described above, the fluidized bed catalytic softening system of the present invention with online seed activity regeneration function has at least the following beneficial effects: by setting up a seed activity regeneration module, using a seed surface state monitoring module to monitor seed activity in real time, and triggering an ultrasonic-microbubble synergistic cleaning module and a broadband excitation module to perform multi-frequency synergistic cleaning, the inert layer covering the seed surface can be effectively stripped off, the surface activity of the seed can be restored, thereby extending the seed service life and reducing operating costs. Attached Figure Description

[0017] Figure 1 The diagram shown is a simplified structural schematic of a fluidized bed catalytic softening system with online seed activity regeneration function according to the present invention.

[0018] Figure 2 The diagram shown is a simplified schematic of a portion of the structure of a fluidized bed catalytic softening system with online seed activity regeneration function according to the present invention.

[0019] Figure 3 The diagram shown is a simplified structural schematic of another part of a fluidized bed catalytic softening system with online seed activity regeneration function according to the present invention.

[0020] Figure 4 The diagram shows a simplified structural schematic of a piezoelectric ceramic stack and elastic support frame of a fluidized bed catalytic softening system with online seed activity regeneration function according to the present invention.

[0021] Figure 5 The diagram shown is a simplified structural schematic of a portion of a fluidized bed catalytic softening system with online seed activity regeneration function according to the present invention.

[0022] Figure 6 The diagram shown is a simplified schematic of the nozzle structure of a fluidized bed catalytic softening system with online seed activity regeneration function according to the present invention.

[0023] Figure 7 The diagram shows a simplified structural schematic of the self-cleaning module of a fluidized bed catalytic softening system with online seed activity regeneration function according to the present invention.

[0024] Component designation explanation: 1. Fluidized bed crystallization softening tower; 11. Seed outlet; 12. Softened water outlet; 13. Seed replenishment outlet; 14. Softened water overflow weir; 15. Softened water collection tank; 16. Acidification outlet; 17. Acidification inlet; 18. First pH online detector; 19. Dissolved carbon dioxide online sensor. 2. Water inlet module, 21. Water inlet pipe, 22. Cyclone feeder, 221. Venturi tube, 222. Cyclone blade assembly, 23. Guide tube; 3. pH adjustment module; 31. Second online pH detector; 32. Metering pump; 33. Alkali storage tank; 4. Grain classification bed; 41. Wedge wire mesh assembly; 42. Support frame; 421. Upper support ring; 422. Lower support ring; 43. Collecting cone; 44. Return channel. 51. Ultrasonic-microbubble synergistic cleaning module; 511. Microbubble generator; 5111. Second circulation pump; 5112. Second dissolved gas tank; 5113. Second switching valve; 5114. Third pipeline; 5115. Second pressure detection element; 512. Ultrasonic transducer; 52. Seed surface condition monitoring module; 521. Electrochemical impedance sensor; 522. Laser particle size analyzer; 53. Wideband excitation module; 531. Mounting bracket; 532. Ring electromagnet; 533. Piezoelectric ceramic stack; 534. Elastic support frame. 6. Acidity adjustment module; 61. First circulation pump; 62. First dissolved gas tank; 621. Gas flow controller; 622. pH-dissolved carbon dioxide linkage controller; 63. Gas release device; 64. First pipeline; 65. Second pipeline; 651. First switch valve; 66. Intermediate water tank; 661. First pressure detection element; 67. Spray head; 671. Nozzle; 68. Agitator; 69. Turnover box; 71. Hydraulic turbine-brush roller cleaning module; 711. Hydraulic turbine; 712. Drive shaft; 713. Brush roller; 72. Pulse backflushing cleaning module; 721. Compressed air tank; 722. Pulse valve. Detailed Implementation

[0025] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0026] Please refer to all the accompanying drawings below. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0027] The following embodiments are for illustrative purposes only. These embodiments can be combined and are not limited to the content shown in any single embodiment below.

[0028] Please see Figures 1-3 This invention provides a fluidized bed catalytic softening system with online seed crystal activity regeneration. The system mainly includes a fluidized bed crystallization softening tower 1, an influent module 2, a pH adjustment module 3, a crystal classification bed 4, a seed crystal activity regeneration module, and a control module, among other core components. These modules work collaboratively through pipelines, lines, or mechanical connections to form a complete fluidized bed catalytic softening system.

[0029] The fluidized bed crystallization softening tower 1 is the core reaction vessel of the entire system. Its main structure is a vertical cylinder, and the material can be corrosion-resistant 316L stainless steel or carbon steel lined with rubber. The bottom of the fluidized bed crystallization softening tower 1 is equipped with a raw water inlet and a seed crystal outlet 11, while the top is equipped with a softened water outlet 12 and a seed crystal replenishment inlet 13. The top of the tower is equipped with a softened water overflow weir 14 and a softened water collection tank 15, which is connected to the softened water outlet 12. Both the softened water overflow weir 14 and the softened water collection tank 15 are located above the seed crystal outlet 11. It is particularly noteworthy that the seed crystal outlet 11 is located below the raw water inlet. This design utilizes the principle of gravity settling, facilitating the smooth discharge of large-particle crystals or aged seed crystals deposited at the bottom of the tower under gravity, preventing blockage of the raw water inlet or affecting the uniformity of water distribution at the bottom.

[0030] The water inlet module 2 includes an inlet pipe 21, a cyclone feeder 22, and a guide tube 23. The first end of the inlet pipe 21 passes through the raw water inlet and is located inside the fluidized bed crystallization softening tower 1. The cyclone feeder 22 is connected to the inlet pipe 21. The guide tube 23 is fixed to the inner wall of the fluidized bed crystallization softening tower 1, above the first end of the inlet pipe 21. The function of the cyclone feeder 22 is to initially mix the raw water, reagents, and refluxed small-particle seed crystals entering the tower, thereby enhancing mass transfer efficiency and eliminating the bottom reaction dead zone by generating a cyclone field.

[0031] pH adjustment module 3 is connected to water inlet pipe 21 and is used to adjust the pH value of the water entering fluidized bed crystallization softening tower 1.

[0032] A grain-grading bed 4 is disposed within the fluidized bed crystallization softening tower 1, located above the cyclone feeder 22 and below the softened water outlet 12 and the seed crystal replenishment port 13, for classifying the seed crystals by particle size. The grain-grading bed 4 functions as a built-in sieving device, intercepting larger seed crystals and allowing them to remain in the lower part of the bed for continued growth, while allowing smaller seed crystals to pass through and enter the upper reaction zone, thereby maintaining the stability of the seed crystal particle size distribution within the bed. It should be understood that, in this embodiment, the seed crystals fed into the fluidized bed crystallization softening tower 1 through the seed crystal replenishment port 13 are located above the grain-grading bed 4. The seed crystals fed through the seed crystal replenishment port 13 have a particle size of 0.1-0.3 mm and a specific surface area ≥70 cm². 2 The filling height of the calcite seed particles (g / g) is 1 / 3 to 1 / 2 of the effective height of the tower. The effective height of the tower refers to the height of the effective section for the fluidized bed crystallization reaction within the fluidized bed crystallization softening tower 1, from the bottom of the guide tube 23 to the bottom of the clear water overflow weir. Controlling the seed particle filling height within this range ensures that the seed bed is in the optimal fluidization state, providing sufficient crystallization sites, while avoiding excessive fluidization resistance due to overfilling and insufficient crystallization efficiency due to underfilling.

[0033] A seed crystal activity regeneration module is installed inside the fluidized bed crystallization softening tower 1 to perform online cleaning of the seed crystals to restore their surface activity. The seed crystal activity regeneration module includes an ultrasonic-microbubble synergistic cleaning module, a seed crystal surface state monitoring module 52, and a broadband excitation module 53. The seed crystal surface state monitoring module 52 is used to monitor the surface activity state of the seed crystals in real time. Specifically, the seed crystal surface state monitoring module 52 may include an electrochemical impedance sensor 521 and / or a laser particle size analyzer 522; the detection ends of the electrochemical impedance sensor 521 and the laser particle size analyzer 522 are positioned above the grain classification bed 4. The electrochemical impedance sensor 521 determines the degree of scaling or encapsulation on the seed surface by monitoring changes in the impedance value of the seed bed. The laser particle size analyzer 522 is used for online real-time detection of the seed particle size distribution and particle size. Combined with the monitoring of seed surface activity by the electrochemical impedance sensor 521, they together constitute a two-dimensional monitoring system for seed status, providing accurate data support for seed activity regeneration, graded reflux of grains, seed discharge and replenishment, and realizing fully automatic and stable operation of the system. When a decrease in seed activity is detected (e.g., the impedance value exceeds a set threshold), the system automatically triggers the broadband excitation module 53 and the ultrasonic-microbubble synergistic cleaning module to perform multi-frequency synergistic cleaning of the seed.

[0034] The control module can be a control module composed of a PLC control board, which is connected to the pH adjustment module, the seed crystal activity regeneration module, and the sensors or sensor signals mentioned below for detecting pressure, carbon dioxide concentration, etc., and controls the corresponding actuators to perform actions.

[0035] In terms of specific operational logic, this collaborative cleaning mechanism has a significant defensive effect: First, the seed surface condition monitoring module 52 senses the degree of "passivation" on the seed surface in real time; once the cleaning trigger condition is met, the broadband vibration module 53 is activated first, generating broadband vibrations of low and high frequencies to cause complex spatial movements of the seed particles within the fluidized bed, loosening the inert layer that has been hardened or has weak adhesion on the seed surface; then, or simultaneously, the ultrasonic-microbubble collaborative cleaning module is activated, utilizing the cavitation effect of ultrasound and the bursting impact force of microbubbles to deeply clean the seed surface and remove stubborn scale layers. This closed-loop logic of "monitoring trigger - vibration loosening - collaborative cleaning" enables online, on-demand regeneration of seed activity without the need for downtime to replace the seed, significantly extending the lifespan of the seed and reducing operating costs.

[0036] In one implementation, the grain classification bed 4 is set inside the fluidized bed crystallization softening tower 1. Its core function is to perform real-time, online particle size classification of the seed crystals in the fluidized bed in order to maintain the dynamic balance of the seed crystal particle size distribution in the bed.

[0037] Specifically, the grain-grading bed 4 includes a wedge-shaped wire mesh assembly 41, a support frame 42, and a collecting cone 43. The support frame 42, serving as the skeleton of the entire bed, includes an upper support ring 421 and a lower support ring 422. The upper and lower support rings 421 and 422 are fixedly connected to the inner wall of the fluidized bed crystallization softening tower 1, for example, by welding or bolting, ensuring the bed operates stably within the fluidized bed for a long period without displacement or deformation due to fluid impact. In this embodiment, the upper support ring 421 is welded to the inner wall of the fluidized bed crystallization softening tower 1, and the lower support ring 422 is fixedly connected to the upper support ring 421 via multiple spaced connecting rods, thus ensuring that both the upper and lower support rings 421 are also fixed within the fluidized bed crystallization softening tower 1.

[0038] The wedge-shaped wire mesh assembly 41, located between the upper support ring 421 and the lower support ring 422, is a key component for performing the classification function. The wedge-shaped wire mesh assembly 41 comprises multiple layers of wedge-shaped wire mesh, for example, it can be composed of 2 to 5 layers of 316L stainless steel wedge-shaped wire mesh stacked together, with a screen gap width of 0.2 mm and an opening ratio of 30%. The key innovation of this embodiment lies in the staggered arrangement of the mesh openings of adjacent layers of wedge-shaped wire mesh. Specifically, if the mesh openings are aligned, impurities or large particles in the fluid can easily become embedded in the mesh, causing direct blockage; however, through the staggered arrangement, the wires of adjacent layers of wire mesh obstruct each other, forming a tortuous "maze-like" flow channel. This maze effect effectively prevents large crystal particles from getting stuck in the mesh openings, and increases the shear force of the fluid flowing through the mesh surface, making it easier to wash away and remove small crystals adhering to the wire surface, thereby significantly improving the anti-clogging ability of the bed and ensuring the continuity and stability of the classification process. It should be understood that the offset angle of the screen opening can be adjusted according to the characteristics of suspended solids in the actual water being treated, such as offset by 45 or 55 degrees, as long as a non-straight-through screening channel can be formed.

[0039] The collecting cone 43 is connected to the inner wall of the fluidized bed crystallization softening tower 1 and is located between the lower support ring 422 and the cyclone feeder 22. The diameter of the collecting cone 43 gradually increases from the end near the cyclone feeder 22 to the end near the lower support ring 422, forming an inverted cone shape with a cone angle of 55°. This inverted cone shape design utilizes the principles of fluid dynamics. When the rising fluid carrying seed crystals passes through the wedge-shaped wire mesh assembly 41, small seed crystals with a diameter smaller than the sieve slot width continue to move upward through the mesh to participate in the reaction, while large seed crystals with a diameter larger than the sieve slot width are intercepted. The intercepted large seed crystals settle under gravity and slide down along the smooth inner wall of the collecting cone 43 (the inner wall can be polished to reduce frictional resistance).

[0040] A reflux channel 44 is formed between the collecting cone 43 and the inner wall of the fluidized bed crystallization softening tower 1. The reflux channel 44 can be 60 mm wide and have a slope of 50°. This reflux channel 44 is an important "bridge" connecting the classification zone and the bottom reaction zone. Large seed crystals that slide down return to the outlet area of ​​the bottom inlet pipe 21 through the reflux channel 44, where they are remixed with fresh inlet water and reagents to continue participating in the crystal growth reaction or discharged from the system through the seed outlet 11. This process constructs a "classification-reflux" defense depth: large seed crystals will not accumulate above the bed, causing a sharp increase in bed resistance, nor will they be lost with the effluent, resulting in resource waste. Instead, they are forcibly "repatriated" to the bottom for recycling. This in-situ reflux mechanism greatly improves the utilization rate of seed crystals and the operational stability of the system.

[0041] In one implementation, such as Figures 1-3 As shown, the ultrasonic-microbubble synergistic cleaning module includes a microbubble generator 511 and multiple ultrasonic transducers 512. The outlet of the microbubble generator 511 is located above the grain classification bed 4; the multiple ultrasonic transducers 512 are arranged in an array below the grain classification bed 4.

[0042] Specifically, the outlet of the microbubble generator 511 is located above the grain classification bed 4. This positioning is designed to utilize the upward force of the fluid within the fluidized bed. When the microbubble generator 511 operates, a large number of micro- and nano-sized bubbles (with diameters, for example, between 1 and 50 micrometers) are released from above the grain classification bed 4, covering the entire seed bed layer from top to bottom under the influence of the fluid. The microbubbles have a large specific surface area, enabling them to adhere to the dirt layer on the seed surface. Through the flotation effect of the bubbles and the impact of the micro-jet generated when they break, the deposits on the seed surface are initially loosened. As a specific implementation, the outlet of the microbubble generator 511 can adopt an annular pipe structure, arranged around the inner wall of the fluidized bed crystallization softening tower 1 or mounted on the upper support ring 421. Several nozzles are evenly distributed along the annular pipe to ensure the uniform distribution of bubbles across the cross-section and avoid cleaning blind spots with sparse local bubbles.

[0043] Meanwhile, multiple ultrasonic transducers 512 are arranged in an array below the grain classification bed 4. This arrangement allows ultrasonic energy to radiate from bottom to top, penetrating the grain classification bed 4 and acting on the entire seed bed. The ultrasonic transducers 512 can be arranged in a ring array, for example, multiple ultrasonic transducers 512 can be installed on the lower support ring 422 to form a ring-shaped sound field radiation surface. When ultrasonic waves propagate in a liquid, they generate a cavitation effect, where tiny bubbles in the liquid rapidly expand and collapse under the action of ultrasound. The moment of collapse generates extremely high local temperatures and pressures, as well as strong shock waves and microjets. This physical effect can effectively peel off stubborn crystalline scale layers from the seed surface.

[0044] More importantly, this embodiment constructs a synergistic cleaning field by placing the outlet of the microbubble generator 511 above and the ultrasonic transducer 512 below. This spatial layout is not a simple superposition, but produces a significant synergistic effect: on the one hand, the microbubbles released from above provide abundant cavitation nuclei for the ultrasonic waves below, significantly reducing the ultrasonic cavitation threshold and enhancing the cavitation intensity and cleaning efficiency of the ultrasonic waves; on the other hand, the ultrasonic energy radiated from below can promote the dispersion and collapse of microbubbles in the liquid, preventing microbubbles from coalescing into large bubbles and failing during the ascent. This three-dimensional cleaning field ensures that the seed crystals in both the central and peripheral regions of the fluidized bed receive uniform and intense cleaning, completely eliminating the cleaning dead zones present in traditional cleaning methods. In addition, this layout also avoids interference from the cleaning device on the structure of the grain classification bed 4, ensuring the continuity of the classification process.

[0045] like Figures 1-4 As shown, the broadband vibration module 53 includes a mounting frame 531, multiple annular electromagnets 532, a piezoelectric ceramic stack 533, and an elastic support frame 534. The two ends of the mounting frame 531 are fixedly connected to the inner wall of the fluidized bed crystallization softening tower 1, which can be achieved by welding or bolting, ensuring the stability and reliability of the mounting frame 531 during vibration. Multiple annular electromagnets 532 are fixedly arranged at intervals on the mounting frame 531. When energized, the annular electromagnets 532 generate an alternating magnetic field, producing low-frequency mechanical vibration with a frequency of 5-30 Hz. This low-frequency vibration has a strong wavelength and penetrating power, capable of causing a large number of seed crystals in the fluidized bed to undergo macroscopic tumbling and collision, effectively loosening the inert layer that has been hardened or has weak adhesion on the seed crystal surface, creating conditions for subsequent fine cleaning.

[0046] Meanwhile, the piezoelectric ceramic stack 533 is mounted on an elastic support frame 534, which is located on the inner wall of the fluidized bed crystallization softening tower 1. Specifically, it can be positioned between the upper support ring 421 and the lower support ring 422, and between the wedge-shaped wire mesh assembly 41 and the inner wall of the fluidized bed crystallization softening tower 1. The piezoelectric ceramic stack 533 utilizes the inverse piezoelectric effect to generate rapid micron-level expansion and contraction deformation when a high-frequency voltage signal is applied, thereby generating high-frequency vibration. Specifically, the piezoelectric ceramic stack 533 can generate high-frequency vibrations in the frequency range of 20-200Hz. Although the amplitude of this high-frequency vibration is small, the acceleration is extremely high, generating strong shear force at the microscopic level, effectively peeling off tiny scale particles attached to the surface of the seed crystals. The function of the elastic support frame 534 is twofold: firstly, to provide an installation base for the piezoelectric ceramic stack 533; and secondly, to utilize its elastic deformation characteristics to amplify the vibration output of the piezoelectric ceramic while reducing the energy loss transmitted to the tower body.

[0047] The core advantage of this embodiment lies in achieving a composite vibration of "low frequency + high frequency". In actual operation, the control system can coordinate the output of the ring electromagnet 532 and the piezoelectric ceramic stack 533, so that the vibrations generated by the two are superimposed in the fluidized bed. The low-frequency vibration is responsible for "loosening", and the high-frequency vibration is responsible for "peeling". The two work together to form a wide-frequency excitation field. This wide-frequency excitation can adapt to scale layers with different particle sizes and different adhesion strengths on the seed surface, significantly improving the efficiency of seed active regeneration. It should be understood that although this embodiment describes the preferred combination of low-frequency vibration generated by the ring electromagnet 532 and high-frequency vibration generated by the piezoelectric ceramic stack 533, in other embodiments, the frequency range of the two can be adjusted or other types of excitation generators can be used according to actual needs, as long as the technical effect of wide-frequency composite vibration can be achieved.

[0048] In one implementation, such as Figure 1 , Figure 5 As shown, this system also includes an acid adjustment module 6, and the fluidized bed crystallization softening tower 1 also includes an acid adjustment outlet 16 and an acid adjustment inlet 17. The acid adjustment inlet 17 is located between the acid adjustment outlet 16 and the softened water outlet 12; the acid adjustment outlet 16 is located above the seed crystal activity regeneration module. The placement of the acid adjustment outlet 16 above the seed crystal activity regeneration module ensures that the extracted liquid is the upper clear liquid after sufficient softening treatment, avoiding the intake of seed crystal particles from the bottom; while the location of the acid adjustment inlet 17 between the acid adjustment outlet 16 and the softened water outlet 12 allows the water after acid treatment to be mixed and buffered in the upper part of the tower when it flows back into the tower, and then flows out stably from the softened water outlet 12, avoiding direct impact of acidic water on the bottom crystallization reaction zone and ensuring the stability of the softening reaction environment.

[0049] The acid adjustment module 6 is connected to the acid adjustment inlet 17, the acid adjustment outlet 16, and the external system. The acid adjustment module 6 draws water from the fluidized bed crystallization softening tower through the acid adjustment outlet 16, treats it with carbon dioxide from the industrial flue gas introduced into the external system, and then discharges it back into the fluidized bed crystallization softening tower 1 through the acid adjustment inlet 17. This external system can be a factory boiler flue gas emission system containing a high concentration of carbon dioxide, or it can be a storage tank containing industrial flue gas. By introducing industrial flue gas, this embodiment achieves the dual purpose of "treating waste with waste": on the one hand, the carbon dioxide in the flue gas is used as an acidic regulator to neutralize the high pH value of the softened water (usually in the pH range of 10.0-10.5), adjusting it to a pH range that meets the standards for subsequent membrane treatment or discharge (e.g., pH 8.0-9.0), saving the cost of adding industrial hydrochloric acid or sulfuric acid in traditional processes; on the other hand, carbon dioxide is fixed in the water through a mineralization reaction and converted into bicarbonate ions (HCO3-), achieving carbon emission reduction and having significant environmental benefits.

[0050] Specifically, the acid-adjusting module 6 includes a first circulation pump 61, a first dissolved gas tank 62, a gas release device 63, a first pipeline 64, a second pipeline 65, a first pressure sensor 661, and an intermediate water tank 66. The first circulation pump 61 is connected to the first dissolved gas tank 62 and the acid-adjusting outlet 16. The first dissolved gas tank 62 is a closed pressure vessel and is also connected to an external system to deliver industrial flue gas containing carbon dioxide from the external system into the first dissolved gas tank 62. The first circulation pump 61 provides power to draw softened water from the acid-adjusting outlet 16 and pump it into the first dissolved gas tank 62. The first dissolved gas tank 62 is a key pressure vessel where industrial flue gas from the external system is injected and mixed with water. Under pressurized conditions (e.g., 0.4-1.0 MPa), the solubility of carbon dioxide gas in water increases significantly, forming supersaturated dissolved gas water. A gas flow controller 621 and a pH-dissolved carbon dioxide linkage controller 622 are installed on the pipeline connecting the first dissolved gas tank 62 to the external system. The gas flow controller 621 is used to precisely control the flow rate of carbon dioxide flue gas entering the first dissolved gas tank 62. It automatically adjusts the opening degree according to the control signal to ensure a stable and uniform carbon dioxide supply. The pH-dissolved carbon dioxide linkage controller 622 is also connected to a first online pH detector and a dissolved carbon dioxide online sensor 19 located at the softened water outlet 12. The first online pH detector transmits the real-time pH value to the pH-dissolved carbon dioxide linkage controller 622 as the main adjustment parameter for acidity control, ensuring that the pH of the effluent remains stable within the target range. The dissolved carbon dioxide online sensor 19 transmits the real-time dissolved carbon dioxide concentration to the pH-dissolved carbon dioxide linkage controller 622 as an auxiliary adjustment parameter for mineralization efficiency and gas dosage, preventing excessive carbon dioxide loss or insufficient dosage. The pH-dissolved carbon dioxide linkage controller 622 automatically outputs a control signal according to the set parameters, adjusting the opening degree of the gas flow controller 621 and the operating status of the first circulating pump 61, so that carbon dioxide is fully dissolved in the water and undergoes a carbonation reaction, stabilizing the pH of the softened effluent to the target range, while simultaneously achieving carbon dioxide mineralization and resource utilization. The first dissolved gas tank 62 is also equipped with a pressure detection sensor, which is used to detect the pressure inside the first dissolved gas tank 62.

[0051] A gas release device 63 is installed inside the intermediate water tank 66. The gas release device 63 is connected to the first dissolved air tank 62 via a first pipe 64. A first pressure detection element 661, which can be a pressure sensor, is installed inside the intermediate water tank 66 to monitor the pressure within the tank in real time, ensuring dissolved air efficiency. The intermediate water tank 66 is also connected to the acid-adjusting inlet 17 via a second pipe 65. When supersaturated dissolved air water flows through the gas release device 63, the pressure drops sharply, and the dissolved carbon dioxide is released in the form of micro-nano bubbles. These micro-nano bubbles have a huge specific surface area, greatly increasing the gas-liquid contact area and enhancing the mass transfer reaction rate between carbon dioxide and hydroxide and carbonate ions in the water. The intermediate water tank 66 acts as a reaction buffer container, providing sufficient residence time for the dissolution of carbon dioxide and acid-base neutralization reactions, ensuring that the pH of the effluent remains stable and meets the standards.

[0052] Please see Figure 1 , Figure 6 The acid-adjusting module 6 also includes multiple nozzles 67 and an agitator 68. The multiple nozzles 67 are arranged in a ring at intervals within the fluidized bed crystallization softening tower 1. Each nozzle 67 is connected to an intermediate water tank 66 via a second pipe. Each nozzle 67 is equipped with multiple nozzles 671, wherein the nozzles 671 at the circular point of the virtual circle created by the ring arrangement of the multiple nozzles 67 are horizontally arranged, while the remaining nozzles 67 are inclined towards the horizontal plane, specifically towards the top of the fluidized bed crystallization softening tower 1 at an angle of 20°. The agitator 68 is located at the top of the fluidized bed crystallization softening tower 1, with its stirring end passing through the softened water overflow weir 14 and positioned on the central axis of the virtual circle created by the ring arrangement of the multiple nozzles 671, and above this virtual circle, to agitate the water sprayed from the nozzles 67, thereby accelerating water mixing.

[0053] This implementation also provides a specific embodiment in which the microbubble generator 511 and the acid adjustment module 6 share the same piping. The acid adjustment module 6 also includes a first switching valve 651 disposed on the second piping 65. The microbubble generator 511 includes a second circulating pump 5111, a second dissolved air tank 5112, a second switching valve 5113, a third piping 5114, and a second pressure sensor 5115. The second circulating pump 5111 is connected to the softened water outlet 12 and the second dissolved air tank 5112. The second dissolved air tank 5112 is also a closed pressure vessel, which is connected to the gas release device 63 through a pipe, and the second dissolved air tank 5112 is also connected to the external atmosphere. The third piping 5114 is connected to the intermediate water tank 66 and the fluidized bed crystallization softening tower 1; the second switching valve 5113 and the second pressure sensor 5115 are disposed on the third piping 5114. The first switching valve 651 and the second switching valve 5113 can be solenoid valves, and the second pressure sensor 5115 can be a pressure sensor.

[0054] This pipeline reuse design reflects a high degree of integration: the gas releaser 63, as a core component, serves both the acid adjustment module 6 and the microbubble generator 511 of the seed crystal activity regeneration module. When the system needs to clean the seed crystals, the first switch valve 651 is closed, blocking the path between the intermediate water tank 66 and the acid adjustment inlet 17. The second circulation pump 5111 draws softened water from the softened water outlet 12 into the second dissolved air tank 5112. The second dissolved air tank 5112 is also connected to the external atmosphere, allowing air to mix with the softened water in the second containment pipe. Then, the second switch valve 5113 is opened, allowing the dissolved air water in the intermediate water tank 66 to flow directly into the fluidized bed crystallization softening tower 1 through the third pipeline 5114. At this time, the microbubbles released by the gas releaser 63 are used for cleaning the seed crystal surface. When the system needs to perform acid adjustment, the first switch valve 651 is opened and the second switch valve 5113 is closed, allowing the dissolved air water to enter the intermediate water tank 66 for reaction. Through the independent control logic of the first switching valve 651 and the second switching valve 5113, the system can flexibly switch between "acid adjustment mode" and "cleaning mode," greatly improving equipment utilization and reducing the complexity of pipeline layout. A flow controller can also be installed at the connection point between the second dissolved gas tank 5112 and the external atmosphere to control the amount of gas entering the second container. A pressure sensor can also be installed inside the second dissolved gas tank 5112 to detect its pressure.

[0055] In an optional embodiment, the acid adjustment module 6 further includes a transfer box 69, which is connected to the intermediate water tank 66 and the acid adjustment inlet 17. In this case, during the acid adjustment process, the water in the intermediate water tank 66 first enters the transfer box 69, and then enters the fluidized bed crystallization softening tower 1.

[0056] In one implementation, the cyclone feeder 22 includes a venturi tube 221 and a cyclone blade assembly 222. The venturi tube 221 is connected to the second end of the water inlet pipe 21, and the cyclone blade assembly 222 is connected to the second end of the water inlet pipe 21. The cyclone blade assembly 222 may consist of eight twisted blades with a twist angle of 35°, used to create a cyclone-jet composite motion between the water, reagent, and seed crystals.

[0057] The Venturi tube 221, a classic fluid transport and mixing component, features an internal flow channel design including a constriction section, a throat, and a diffuser section. When raw water flows through the constriction section of the Venturi tube 221 under pump pressure, the flow velocity increases. According to Bernoulli's principle, this increased velocity leads to a decrease in static pressure, creating a negative pressure zone at the throat. The Venturi tube 221 is equipped with an alkali inlet, specifically located at the throat. This design cleverly utilizes fluid dynamics principles, automatically drawing alkali into the tube under the negative pressure at the throat without requiring additional power equipment. The pH adjustment module 3 includes a second online pH meter, a metering pump 32, and an alkali storage tank 33. The second online pH meter is connected to the inlet pipe 21 to monitor the pH value of the incoming water in real time; one end of the metering pump 32 is connected to the alkali inlet of the Venturi tube 221, and the other end is connected to the alkali storage tank 33. Based on feedback signals from the second online pH meter, the control module controls the opening and closing of the metering pump 32 to precisely control the flow rate of alkali solution drawn from the alkali storage tank 33 and delivers it to the throat of the venturi tube 221. At the throat, the high-speed flowing raw water and the drawn-in alkali solution undergo intense turbulent mixing, achieving instantaneous and uniform mixing of the reagent and the water. This "negative pressure suction + turbulent mixing" method, compared to traditional direct pipeline dosing, significantly improves mixing efficiency and avoids localized pH imbalances caused by uneven mixing. This creates a more stable and uniform chemical environment for the subsequent crystallization reaction, contributing to the formation of uniformly sized crystal particles.

[0058] In one implementation, the system further includes a seed recovery module (not shown in the figure). This module is connected to the seed discharge port 11 and seed inlet of the fluidized bed crystallization softening tower 1. It separates the seed slurry discharged from the fluidized bed crystallization softening tower 1, returning the separated fine seed crystals to the seed replenishment port 13 for reuse, and recovering the separated large crystal particles as a byproduct. The introduction of the seed recovery module establishes a complete closed-loop "seed lifecycle management" system, solving the problem of disordered seed loss or the need for complete external discharge in traditional fluidized bed processes.

[0059] Specifically, the seed crystal recovery module includes a hydrocyclone separator (not shown in the figure), a crystal particle collection tank (not shown in the figure), and a seed crystal reuse pipe (not shown in the figure). The hydrocyclone separator, as the core separation device, has its inlet connected via a pipeline to the seed crystal discharge outlet 11 at the bottom of the fluidized bed crystallization softening tower 1. During operation, the seed crystal slurry (containing large crystal particles, small seed crystals, and some suspension) deposited at the bottom of the fluidized bed crystallization softening tower 1 is transported to the hydrocyclone separator under pressure within the tower or by an auxiliary pump.

[0060] Hydrocyclones utilize fluid dynamics principles for separation. When seed crystal slurry enters the hydrocyclone tangentially, a high-speed rotating flow field is formed inside. Under centrifugal force, denser, larger particles are thrown against the hydrocyclone wall and spiral downwards along the wall, eventually being discharged through the underflow outlet. Meanwhile, smaller, less dense seed crystals accumulate in the central region of the hydrocyclone, moving upwards with the internal swirling flow and being discharged through the overflow outlet. This physical separation method based on particle size differences requires no additional chemical reagents, resulting in high separation efficiency and low operating costs.

[0061] The key to this embodiment lies in the differentiated design of the separation path. The underflow outlet of the hydrocyclone separator is connected to the crystallization particle collection tank. The particles discharged from the underflow outlet are mainly large, mature crystallization particles (such as calcite particles). The surface activity of these particles has been significantly reduced, making them unsuitable as seed crystals to remain in the bed; otherwise, they would occupy effective reaction space and increase bed resistance. After these large crystallization particles enter the crystallization particle collection tank, they can undergo subsequent processing such as dehydration and drying, and be utilized as a high-purity calcium carbonate byproduct for resource recovery, such as in the production of building materials or industrial fillers. This achieves "turning waste into treasure" and reduces the overall operating cost of the system.

[0062] Meanwhile, the overflow port of the hydrocyclone separator is connected to the seed inlet via a seed return pipe. The discharge from the overflow port mainly consists of small-sized fine seed crystals and a portion of liquid. These fine seed crystals still possess high surface activity and are the core carriers for the crystallization reaction. Through the seed return pipe, these fine seed crystals are transported back to the seed replenishment port 13 at the top of the fluidized bed crystallization softening tower 1, re-entering the tower to participate in the crystallization reaction. This design constructs a closed-loop path of "fine seed return," significantly reducing the amount of fresh seed crystals needed, maintaining the dynamic balance of seed particle size distribution within the bed, and ensuring long-term stable operation of the system. It should be understood that although this embodiment describes a preferred scheme for solid-liquid separation and particle size classification using a hydrocyclone separator.

[0063] In one implementation, please refer to Figure 7The system also includes a self-cleaning module, which comprises a hydraulic turbine-brush roller cleaning module 71 and a pulse backflushing cleaning module 72. The hydraulic turbine-brush roller cleaning module 71 is mounted on the water inlet pipe 21 and includes a hydraulic turbine 711, a drive shaft 712, and a brush roller 713. The hydraulic turbine 711 is driven to rotate by the incoming water flow, which in turn drives the brush roller 713 to rotate via the drive shaft 712. The brush roller 713 has nylon bristles on its surface to clean the water inlet pipe 21. The pulse backflushing cleaning module 72 is connected to the seed crystal recycling pipe and includes a compressed air tank 721 and a pulse valve 722. The compressed air tank 721 and the pulse valve 722 are connected, and the pulse valve 722 is in turn connected to the seed crystal recycling pipe. During cleaning, the gas in the compressed air tank 721 is used to flush the inner wall of the seed crystal recycling pipe. All modules of the self-cleaning system are linked to the control module, automatically starting the cleaning program according to the operating status.

[0064] On the other hand, the present invention also provides a fluidized bed catalytic softening method with online seed activity regeneration function, including the above-mentioned fluidized bed catalytic softening system with online seed activity regeneration function, and further including the following steps: Step S100: System initialization and seed filling. Calcite seed particles are filled into the fluidized bed crystallization softening tower 1 to the set height. The control module is started, and the pH control parameters are set.

[0065] Step S200: Inlet Water and pH Adjustment. High-hardness mine water enters from the bottom of the tower. The second online pH meter monitors the inlet water pH in real time. The control module automatically adjusts the dosage of the alkali metering pump 32 according to the set value, so that the pH in the reaction zone inside the tower is stabilized between 10.0 and 10.5. Specifically, the alkali solution (such as 25% NaOH solution) is drawn in by the negative pressure of the Venturi tube 221 and instantaneously and uniformly mixed with the inlet water in the cyclone feeder 22, forming a cyclone-jet composite motion, which enhances the mixing effect of the reagent and the water and eliminates local reaction dead zones.

[0066] Step S300: Fluidized bed crystallization and softening. Under alkaline conditions, Ca2+ reacts with HCO3- to form CaCO3, which undergoes heterogeneous nucleation and growth on the surface of calcite seed crystals. The rising crystals flow through the grain-classifying bed 4. Fine seed crystals with a diameter smaller than the sieve slot width (e.g., 0.2 mm) pass through the multi-layer wedge-shaped wire mesh assembly 41 and enter the upper crystal bed to participate in the crystallization reaction. Larger seed crystals with a diameter larger than the sieve slot width are intercepted and slide down along the collecting cone 43, returning to the bottom of the guide cylinder 23 via the reflux channel 44 to continue growing. This "classification-reflux" process achieves in-situ classification and circulation of the grains, effectively maintaining the stability of the seed crystal size distribution within the bed.

[0067] Step S400: Online regeneration of seed crystal activity. During continuous system operation, the electrochemical impedance sensor 521 monitors the scaling state on the seed crystal surface in real time, and the laser particle size analyzer 522 detects the particle size distribution and particle size of the seed crystal online in real time. When a decrease in seed crystal activity is detected (e.g., the impedance value exceeds a set threshold), the control module triggers the broadband excitation module 53 and the ultrasonic-microbubble co-cleaning module. The annular electromagnet 532 generates low-frequency vibration of 5-30Hz, and the piezoelectric ceramic stack 533 generates high-frequency vibration of 20-200Hz. The two combine to form broadband excitation, loosening the inert layer on the seed crystal surface; at the same time, the microbubble generator 511 and the ultrasonic transducer 512 work together to peel off the deposits on the seed crystal surface.

[0068] Step S500: Seed separation and reuse. The seed slurry periodically discharged from the bottom of the tower enters a hydrocyclone separator. Fine seed crystals are returned to the tower from the overflow port for continued use, while large crystal particles enter the crystal particle collection tank. After dehydration, calcite crystal particles are obtained as a byproduct, thus realizing resource recycling.

[0069] Step S600: Carbon dioxide acidification and carbonation. Softened effluent enters the first dissolved air tank 62, while external industrial flue gas is introduced into the acidification module 6. Under the action of the first circulating pump 61, the softened effluent and flue gas are thoroughly mixed and dissolved in the first dissolved air tank 62 at a pressure of 0.4-1.0 MPa. Subsequently, the gas is abruptly depressurized and released through the gas release device 63, generating micro-nano bubbles with a diameter of 1-50 μm. These carbon dioxide micro-nano bubbles significantly increase the gas-liquid contact area, enhance mass transfer efficiency, and adjust the pH of the softened effluent from 10.0-10.5 to 8.0-9.0.

[0070] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0071] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A fluidized bed catalytic softening system with online seed crystal regeneration function, characterized in that, include: A fluidized bed crystallization softening tower, wherein the bottom of the fluidized bed crystallization softening tower is provided with a raw water inlet and a seed outlet, and the top is provided with a softened water outlet and a seed replenishment outlet, and the seed outlet is located below the raw water inlet; The water inlet module includes a water inlet pipe and a cyclone feeder. The first end of the water inlet pipe passes through the raw water inlet and is located inside the fluidized bed crystallization softening tower. The cyclone feeder is connected to the water inlet pipe and is used to mix the raw water, reagents and refluxed small-particle seed crystals entering the tower. A pH adjustment module, connected to the inlet pipe, is used to adjust the pH value of the water entering the fluidized bed crystallization softening tower. A grain classification bed is provided inside the fluidized bed crystallization softening tower, located above the cyclone feeder and below the softened water outlet and the seed crystal replenishment port, for classifying the seed crystals by particle size. A seed crystal activity regeneration module is provided inside the fluidized bed crystallization softening tower for online cleaning of the seed crystals to restore their surface activity. The seed crystal activity regeneration module includes an ultrasonic-microbubble synergistic cleaning module, a seed crystal surface state monitoring module, and a broadband excitation module. The seed crystal surface state monitoring module is used to monitor the seed crystal surface activity state in real time. When the seed crystal activity is detected to be decreasing, the broadband excitation module and the ultrasonic-microbubble synergistic cleaning module perform multi-frequency synergistic cleaning on the seed crystal.

2. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 1, characterized in that: The grain classification bed includes a wedge-shaped wire mesh assembly, a support frame, and a collection cone; The support frame includes an upper support ring and a lower support ring, which are connected to the inner wall of the fluidized bed crystallization softening tower. The wedge-shaped wire mesh assembly is disposed between the upper support ring and the lower support ring; the wedge-shaped wire mesh assembly includes multiple layers of wedge-shaped wire mesh, and the mesh openings of adjacent two layers of wedge-shaped wire mesh are staggered; The collecting cone is connected to the inner wall of the fluidized bed crystallization softening tower and is located between the lower support ring and the cyclone feeder; a reflux channel is formed between the collecting cone and the inner wall of the fluidized bed crystallization softening tower. The diameter of the collecting cone gradually increases from the end near the cyclone feeder to the end near the lower support ring.

3. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 1, characterized in that: The ultrasonic-microbubble synergistic cleaning module includes a microbubble generator and multiple ultrasonic transducers. The outlet of the microbubble generator is located above the grain classification bed; the multiple ultrasonic transducers are arranged in an array below the grain classification bed.

4. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 3, characterized in that: The seed crystal surface state monitoring module includes an electrochemical impedance sensor and / or a laser particle size analyzer, wherein the electrochemical impedance sensor and the laser particle size analyzer are arranged above the grain classification bed; And / or, the broadband excitation module includes a mounting frame, multiple annular electromagnets, a piezoelectric ceramic stack, and an elastic support frame; both ends of the mounting frame are connected to the inner wall of the fluidized bed crystallization softening tower, and the multiple annular electromagnets are spaced apart on the mounting frame; the piezoelectric ceramic stack is disposed on the elastic support frame, and the elastic support frame is disposed on the inner wall of the fluidized bed crystallization softening tower.

5. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 3, characterized in that: It also includes an acid adjustment module, and the fluidized bed crystallization softening tower further includes an acid adjustment outlet and an acid adjustment inlet; the acid adjustment inlet is located between the acid adjustment outlet and the softened water outlet; the acid adjustment outlet is located above the seed crystal activity regeneration module; The acid adjustment module is connected to the acid adjustment inlet, the acid adjustment outlet and the external system. The acid adjustment module is used to draw water out of the fluidized bed crystallization softening tower through the acid adjustment outlet, and after acid adjustment treatment by carbon dioxide in the industrial flue gas introduced into the external system, the water is discharged into the fluidized bed crystallization softening tower through the acid adjustment inlet.

6. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 5, characterized in that: The acid-adjusting module includes a first circulating pump, a first dissolved gas tank, a gas release device, a first pipeline, a second pipeline, and an intermediate water tank; The first circulating pump is connected to the first dissolved gas tank and the acid-adjusting outlet, and the first dissolved gas tank is also connected to the external system; The gas release device is installed in the intermediate water tank. The gas release device is connected to the first dissolved gas tank through a first pipeline. The intermediate water tank is also connected to the acid-adjusting water inlet through a second pipeline.

7. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 6, characterized in that: The acid adjustment module also includes a first switching valve; the first switching valve is disposed on the second pipeline; The microbubble generator includes a second circulating pump, a second dissolved air tank, a second switching valve, and a third pipeline; the second circulating pump is connected to the softened water outlet and the second dissolved air tank, and the second dissolved air tank is connected to the outside atmosphere; the second dissolved air tank is also connected to the gas release device through a pipeline, and the third pipeline is connected to the intermediate water tank and the fluidized bed crystallization softening tower; the second switching valve is located on the third pipeline.

8. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 1, characterized in that: The cyclone feeder includes a venturi tube and a cyclone blade assembly; the venturi tube is connected to the second end of the water inlet pipe, and the cyclone blade assembly is connected to the first end of the water inlet pipe; the venturi tube has a constriction section, a throat, and a diffuser section, and the throat is provided with an alkali inlet; the pH adjustment module includes a second online pH meter, a metering pump, and an alkali storage tank; the second online pH meter is connected to the water inlet pipe; one end of the metering pump is connected to the alkali inlet of the venturi tube, and the other end is connected to the alkali storage tank.

9. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 1, characterized in that: It also includes a seed crystal recovery module, which is connected to the seed crystal discharge port and the seed crystal inlet of the fluidized bed crystallization softening tower. The seed crystal recovery module is used to separate the seed crystal slurry discharged from the fluidized bed crystallization softening tower, so that the separated fine seed crystals are returned to the seed crystal replenishment port for reuse, and the separated large particle crystals are recovered as by-products.

10. The fluidized bed catalytic softening system with online seed crystal activity regeneration function according to claim 9, characterized in that: The seed crystal recovery module includes a hydrocyclone separator, a crystal particle collection tank, and a seed crystal recycling pipe. The hydrocyclone separator is connected to the seed crystal discharge outlet, its underflow outlet is connected to the crystal particle collection tank, and its overflow outlet is connected to the seed crystal inlet through the seed crystal recycling pipe.

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