Desulfurization wastewater zero discharge system based on magnetic seed crystal induction and treatment method

Abstract

The invention discloses a desulfurization wastewater zero discharge system based on magnetic seed crystal induction and a treatment method, the desulfurization wastewater zero discharge system based on magnetic seed crystal induction comprises a premixing module, an atomization module, a magnetic separation module and a regeneration module, the premixing module is used for mixing and conveying slurry, the atomization module is connected with the premixing module and located at the downstream of the premixing module, the atomization module is used for atomizing slurry, the magnetic separation module is connected with the atomization module and located at the downstream of the atomization module, the magnetic separation module is used for capturing and separating magnetic particles, the regeneration module is connected between the premixing module and the regeneration module, and the regeneration module is used for recycling magnetic seed crystals. According to the desulfurization wastewater zero discharge system based on magnetic seed crystal induction disclosed by the invention, a cured product is physically isolated from boiler fly ash while wastewater salt is efficiently cured in flue gas, so that zero discharge of desulfurization wastewater is realized, additional evaporative crystallization equipment is not needed, the magnetic seed crystal can be recycled, and the operation cost is reduced.

Description

A zero-discharge system and treatment method for desulfurization wastewater induced by magnetic seed crystals Technical Field

[0001] This invention relates to the field of desulfurization wastewater and flue gas drying technology, and in particular to a zero-discharge system and treatment method for desulfurization wastewater based on magnetic seed induction. Background Technology

[0002] Related technologies indicate that in the zero-discharge technology route for desulfurization wastewater from coal-fired power plants, spray drying of desulfurization wastewater using high-temperature flue gas before the air preheater or bypass high-temperature flue gas is a mainstream and energy-saving process. The basic principle is to atomize the desulfurization wastewater and spray it into the flue gas duct, using the heat of the flue gas to rapidly evaporate the moisture. The salts and impurities in the wastewater form solid particles, which are then collected by the dust collector along with the flue gas.

[0003] However, existing technologies have a major drawback: the impurities (mainly chloride ions, sulfate ions, and heavy metals) in the dried wastewater mix with the fly ash already present in the flue gas. This leads to excessive chloride ion content in the fly ash, severely affecting its comprehensive utilization as a building material (such as cement additives and concrete admixtures), and even causing the fly ash to become hazardous waste that is difficult to treat.

[0004] Current improvement solutions mainly include: 1. Front-end pre-dust removal: Installing a cyclone dust collector before the main flue gas is sprayed. The disadvantage is increased system resistance and poor separation effect for fine fly ash, with a remaining risk of mixing. 2. Chemical agglomeration / inertial separation: Adding conventional polymeric agglomerants to increase salt particle size, utilizing inertial separation. The disadvantage is insufficient density difference between salt and fly ash particles, and secondary breakage or mixing easily occurs in strongly turbulent flue gas, resulting in low separation efficiency. Therefore, an innovative technical solution is urgently needed that can completely distinguish salt particles from fly ash from a physical mechanism, achieving efficient separation of the two. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a zero-discharge system for desulfurization wastewater induced by magnetic seed crystals. This system achieves zero discharge of desulfurization wastewater, eliminates the need for additional evaporation and crystallization equipment, allows for the recycling of magnetic seed crystals, reduces operating costs, and minimizes the generation of secondary waste.

[0006] This invention also proposes a method for drying flue gas from desulfurization wastewater.

[0007] According to a first aspect of the present invention, a zero-discharge system for desulfurization wastewater induced by magnetic seed crystals includes: a premixing module for mixing and conveying a slurry; an atomizing module connected to and located downstream of the premixing module for atomizing the slurry; a magnetic separation module connected to and located downstream of the atomizing module for capturing and separating magnetic particles; and a regeneration module connected between the premixing module and the regeneration module for recovering magnetic seed crystals.

[0008] According to the magnetic seed-induced zero-discharge system for desulfurization wastewater of the present invention, by introducing recyclable magnetic seeds into the desulfurization wastewater, the wastewater salts are efficiently solidified in the flue gas, while the solidified products are physically isolated from the boiler fly ash, thereby achieving zero discharge of desulfurization wastewater. No additional evaporation and crystallization equipment is required, the magnetic seeds can be recycled, reducing operating costs and reducing the generation of secondary waste.

[0009] In some feasible embodiments, the premixing module includes a stirring tank, a magnetic seed feeding device, and a delivery pump. The stirring tank and the delivery pump are connected in sequence. The stirring tank is used for stirring and mixing desulfurization wastewater with magnetic seeds. The magnetic seed feeding device is used for feeding magnetic seeds into the stirring tank. The delivery pump is used for delivering the mixed slurry to the atomization module.

[0010] In some feasible embodiments, the atomizing module includes a flue and an atomizing gun. The flue is connected to the mixing vessel and the regeneration module, and is also connected to a flue gas source. The atomizing gun is located inside the flue to atomize the mixed slurry.

[0011] In some feasible embodiments, the regeneration module includes: a discharge ash hopper, an ultrasonic cleaning tank, a wet magnetic drum separator, and a return pipeline. The ultrasonic cleaning tank is used to treat the salt on the surface of the magnetic seed crystals, the wet magnetic drum separator is used to extract the magnetic seed crystals, one end of the return pipeline is connected to the wet magnetic drum separator, and the other end of the return pipeline is connected to the premixing module.

[0012] In some feasible embodiments, the desulfurization wastewater zero-discharge system based on magnetic seed induction further includes: a detector and a control module. The detector is used to detect the chloride ion concentration in fly ash. The control module is electrically connected to the premixing module, the magnetic separation module, and the detector. The control module is used to control the premixing module, the magnetic separation module, and the detector.

[0013] According to the second aspect of the present invention, the desulfurization wastewater flue gas drying treatment method is applied to the desulfurization wastewater zero-discharge system based on magnetic seed induction according to the first aspect of the present invention. The desulfurization wastewater flue gas drying treatment method includes: step S1, adding magnetic seed crystals to the desulfurization wastewater to be treated and stirring and mixing to obtain a suspension slurry of magnetic seed crystals; step S2, atomizing and spraying the suspension slurry into the flue; step S3, the high-temperature flue gas in the flue causes the water in the slurry to evaporate, so as to induce the impurities and salts in the desulfurization wastewater to adhere to the magnetic seed crystals to form magnetic salt composite particles; step S4, using magnetic field force to capture and separate the magnetic salt composite particles from the flue gas; step S5, peeling the magnetic seed crystals off the magnetic salt composite particles and recycling them.

[0014] According to the desulfurization wastewater flue gas drying treatment method of the present invention, recyclable magnetic seed crystals are introduced into the desulfurization wastewater, and the waste heat of the high-temperature flue gas of the boiler is used to realize the evaporation and drying of the desulfurization wastewater. The pollutants (chloride salts, sulfates, heavy metals, etc.) are directionally separated from the flue gas in the form of magnetic salt composite particles by means of magnetic magnetic force, and finally the magnetic seed crystals are regenerated and reused, thereby realizing zero discharge of desulfurization wastewater. No additional evaporation and crystallization device is required, which saves energy and reduces consumption, has low operating cost, and concentrates pollutants, which is convenient for subsequent salt resource utilization or safe disposal.

[0015] In some feasible embodiments, the magnetic seed crystal is at least one of magnetite powder, γ-Fe2O3, ferrite powder, iron-based alloy powder, or porous ceramic microspheres containing magnetic cores.

[0016] In some feasible embodiments, the average grain size of the magnetic seeds is 5 μm-50 μm.

[0017] In some feasible embodiments, step S1 further includes adding an agglomeration aid to crosslink and agglomerate the fragments of the magnetic seed crystals with the salt microcrystals.

[0018] In some feasible embodiments, the magnetic field force in step S4 is 2000Gs-10000Gs.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] Figure 1 is a schematic diagram of a zero-discharge system for desulfurization wastewater based on magnetic seed induction according to a first aspect of the present invention; Figure 2 is a schematic diagram of a method for drying desulfurization wastewater flue gas according to a second aspect of the present invention.

[0021] Figure reference numerals: 100, Zero-discharge system for desulfurization wastewater induced by magnetic seed crystals; 1, Premixing module; 11, Stirring tank; 12, Transfer pump; 13, Magnetic seed crystal feeding device; 2, Atomization module; 21, Flue; 22, Atomizing gun; 3, Magnetic separation module; 4, Regeneration module; 41, Discharge ash hopper; 42, Ultrasonic cleaning tank; 43, Return pipeline; 44, Wet magnetic drum separator; 200, Flue gas source. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] The following description, with reference to FIG1, describes a zero-discharge system 100 for desulfurization wastewater based on magnetic seed induction according to a first aspect of the present invention.

[0024] As shown in Figure 1, the zero-discharge system 100 for desulfurization wastewater based on magnetic seed induction according to a first aspect of the present invention includes: a premixing module 1, an atomization module 2, a magnetic separation module 3, and a regeneration module 4.

[0025] Specifically, the premixing module 1 is used to mix and transport the slurry, the atomizing module 2 is connected to the premixing module 1 and located downstream of the premixing module 1 in the slurry flow direction, the atomizing module 2 is used to atomize the slurry, the magnetic separation module 3 is connected to the atomizing module 2 and located downstream of the atomizing module 2 in the slurry flow direction, the magnetic separation module 3 is used to capture and separate magnetic particles, and the regeneration module 4 is connected between the premixing module 1 and the regeneration module 4, the regeneration module 4 is used to recover magnetic seed crystals.

[0026] Understandably, the premixing module 1 is used to thoroughly mix desulfurization wastewater with magnetic seeds to form a uniform and stable slurry. The magnetic seeds act as a carrier, promoting the crystallization and precipitation of salts on their surface during subsequent operations, forming composite salt particles with magnetic particles as the core. This increases the density and particle size of the salt particles, facilitating subsequent magnetic separation. Uniform mixing avoids local oversaturation or clogging, improving the stability of the desulfurization wastewater zero-discharge system 100 induced by magnetic seeds. The atomization module 2, located downstream of the premixing module 1, receives the slurry containing magnetic seeds and atomizes it into micron-sized droplets. High-temperature flue gas (typically 300–400℃) rapidly evaporates the droplets, causing water to evaporate. The salts and magnetic seeds co-solidify into solid particles. This utilizes flue gas preheating to achieve wastewater evaporation, eliminating the need for an additional heat source and saving energy. The magnetic seeds guide the directional crystallization of salts, reducing the escape of fine particles.

[0027] The magnetic separation module 3 is located downstream of the atomization drying zone. It is used to selectively capture salt particles containing magnetic seeds from the flue gas flow, while conventional fly ash, which is non-magnetic, continues to enter the subsequent dust collector (such as electrostatic precipitator or bag filter) with the flue gas and is collected separately. Pollutants such as chloride salts and heavy metals are enriched in the magnetic particles, and the fly ash remains in a low-chlorine state. This achieves the physical separation of salt and fly ash, and the separation efficiency is high and is not affected by particle density or turbulence, overcoming the limitations of traditional methods.

[0028] The regeneration module 4 connects the magnetic separation module 3 and the premixing module 1. It is used to wash, desalinate and activate the captured magnetic salt particles, recover the pure magnetic seeds and return them to the premixing module 1 for recycling. In this way, the magnetic seeds can be recycled for a long time, reducing reagent consumption and operating costs, and realizing centralized salt recovery.

[0029] According to an embodiment of the present invention, the desulfurization wastewater zero discharge system 100 based on magnetic seed induction introduces recyclable magnetic seeds into the desulfurization wastewater, thereby achieving efficient solidification of wastewater salts in flue gas and physically isolating the solidified products from boiler fly ash, thus achieving zero discharge of desulfurization wastewater. No additional evaporation and crystallization equipment is required, the magnetic seeds can be recycled, reducing operating costs and reducing the generation of secondary waste.

[0030] In some embodiments of the present invention, as shown in FIG1, the premixing module 1 includes a stirring tank 11, a magnetic seed feeding device, and a delivery pump 12. The stirring tank 11 and the delivery pump 12 are connected in sequence. The stirring tank 11 is used for stirring and mixing desulfurization wastewater with magnetic seeds. The magnetic seed feeding device is used for adding magnetic seeds to the stirring tank 11. The delivery pump 12 is used for conveying the mixed slurry to the atomization module 2. It can be understood that the stirring tank 11 is used to contain desulfurization wastewater and complete the thorough mixing with magnetic seeds, preventing the magnetic seeds from settling or agglomerating, ensuring that each atomized droplet contains magnetic seeds, improving the nucleation consistency of salt particles after drying, and promoting the formation of ions (Cl) in the wastewater. - SO4² - Ca² + (etc.) adsorb or co-precipitate on the surface of magnetic seed crystals, which is beneficial to form composite salt particles with magnetic particles as the core; the magnetic seed crystal feeding device is used to quantitatively, continuously or intermittently add magnetic seed crystals to the stirring tank 11 according to a set ratio, so as to avoid excessive waste or insufficient addition leading to a decrease in separation efficiency; the delivery pump 12 is used to stably pressurize and deliver the uniformly mixed slurry to the downstream atomization module 2, ensuring the uniformity of the atomization process and the drying efficiency.

[0031] In some embodiments of the present invention, as shown in FIG1, the atomizing module 2 includes a flue 21 and an atomizing gun 22. The flue 21 is connected to the stirring tank 11 and the regeneration module 4, and is also connected to the flue gas source 200. The atomizing gun 22 is disposed in the flue 21 to atomize the mixed slurry. It can be understood that the flue 21 is a high-temperature gas channel connecting the flue gas source 200, and also a reaction space for slurry atomization and drying. In this way, the waste heat of the flue gas is utilized more energy-efficiently. The atomizing gun 22 is installed in the flue 21 to receive the mixed slurry from the premixing module 1 and atomize the mixed slurry. The droplet size is small and the distribution is uniform, which increases the contact surface, accelerates water evaporation, improves drying efficiency, and avoids droplet impact on the wall of the flue 21, causing scale or corrosion.

[0032] In some embodiments of the present invention, as shown in FIG1, the regeneration module 4 includes: a discharge ash hopper 41, an ultrasonic cleaning tank 42, a wet magnetic drum separator, and a return pipeline 43. The ultrasonic cleaning tank 42 is used to treat the salt on the surface of the magnetic seed crystals, the wet magnetic drum separator is used to extract the magnetic seed crystals, one end of the return pipeline 43 is connected to the wet magnetic drum separator, and the other end of the return pipeline 43 is connected to the premixing module 1. Understandably, the unloading ash hopper 41 is located below the magnetic separation module 3 and is used to collect and buffer the salt-containing magnetic particles captured by magnetic force, reducing dust spillage. The ultrasonic cleaning tank 42 receives the magnetic salt particles from the unloading ash hopper 41 and effectively removes soluble salts (such as NaCl and CaSO4) and some heavy metal precipitates attached to the surface of the magnetic crystals by injecting liquid (such as water, weak acid / complexing agent solution) and applying high-frequency ultrasound (such as 20–100 kHz) using cavitation effect and micro-jet impact. After cleaning, the slurry enters the wet magnetic drum separator, where the magnetic crystals are adsorbed onto the drum surface of the wet magnetic drum separator and carried out with the drum, while non-magnetic impurities (such as residual fly ash and non-magnetic crystals precipitated from dissolved salts) are discharged with the water flow, achieving high-purity extraction of magnetic crystals.

[0033] For example, wet magnetic drum separators can have magnetic rods with a gap of 20-50mm between them, which ensures magnetic field coverage and prevents fly ash blockage.

[0034] In some embodiments of the present invention, the zero-discharge system 100 for desulfurization wastewater induced by magnetic seed crystals further includes: a detector and a control module. The detector is used to detect the chloride ion concentration in fly ash, and the control module is electrically connected to the premixing module 1, the magnetic separation module 3, and the detector. It is understood that the detector is installed at the fly ash collection point and uses techniques such as online X-ray fluorescence spectroscopy (XRF), ion-selective electrode (ISE), or laser-induced breakdown spectroscopy (LIBS) to measure the chloride element or chloride ion content in fly ash in real time or near real time, and transmits the concentration signal to the control module in digital form.

[0035] For example, when an increase in chloride ion content is detected in fly ash, the control module automatically increases the proportion of magnetic seed crystals or increases the magnetic field strength.

[0036] A zero-discharge system 100 for desulfurization wastewater based on magnetic seed induction according to a specific embodiment of the present invention will now be described with reference to FIG1.

[0037] Specifically, the premixing module uses hydrophilic modified iron tetroxide (Fe3O4) powder with an average particle size of 15μm. In a stirred tank, magnetic seeds are mixed with desulfurization wastewater at a mass ratio of 1:10 (solid-liquid ratio) to form a magnetic suspension slurry. Simultaneously, 0.05% dispersant is added to prevent seed agglomeration. The atomization module extracts flue gas between the economizer outlet and the air preheater inlet, with an extraction volume of 45,000 Nm³ / h (approximately 2-3% of the total flue gas volume). Flue gas temperature: inlet temperature approximately 330℃. A dual-fluid high-efficiency wear-resistant spray gun is used, with the atomized droplet size controlled at 50-80μm. The reaction residence time is designed to be 1.2 seconds to ensure complete droplet evaporation. The magnetic separation module is installed at the end of the bypass flue, 2 meters downstream of the drying reaction zone. The magnetic field uses a rare-earth permanent magnet grid with a surface magnetic field strength of 4000 Gs and a grid gap of 35 mm, ensuring both a wide magnetic field capture range and allowing non-magnetic fly ash to pass through smoothly. A mechanical pneumatic scraper is used for cleaning, operating every 5 minutes. The regeneration module cleans and separates the mixture of magnetic seeds and desulfurization wastewater impurities using recycled industrial water from the plant, with an ultrasonic power of 2 kW and a frequency of 28 kHz. A wet magnetic separator is used to recover the magnetic seeds, with a magnetic field strength of 0.2 T and a seed recovery rate set at 98%.

[0038] According to a second aspect of the present invention, the desulfurization wastewater flue gas drying treatment method is applied to the desulfurization wastewater zero-discharge system 100 based on magnetic seed induction according to the first aspect of the present invention. As shown in FIG2, the desulfurization wastewater flue gas drying treatment method includes: step S1, adding magnetic seed crystals to the desulfurization wastewater to be treated and stirring and mixing to obtain a suspension slurry of magnetic seed crystals; step S2, atomizing and spraying the suspension slurry into the flue duct 21; step S3, the high-temperature flue gas in the flue duct 21 causes the water in the slurry to evaporate, so as to induce the impurities and salts in the desulfurization wastewater to adhere to the magnetic seed crystals to form magnetic salt composite particles; step S4, using magnetic field force to capture and separate the magnetic salt composite particles from the flue gas; step S5, peeling the magnetic seed crystals off the magnetic salt composite particles and recycling them.

[0039] Specifically, in step S1, magnetic seed crystals are added to the desulfurization wastewater to be treated and stirred to obtain a suspension of magnetic seed crystals. The desulfurization wastewater is introduced into the stirring tank 11, and magnetic seed crystals are added according to a set ratio. A uniform and stable suspension is formed by stirring. In step S2, the suspension is atomized and sprayed into the flue 21. The suspension is broken into fine droplets of 10–100 μm by the atomizing gun 22 and sprayed into the flue 21. In step S3, the high-temperature flue gas in the flue 21 causes the water in the slurry to evaporate, thereby inducing the impurities and salts in the desulfurization wastewater to adhere to the magnetic seed crystals to form magnetic salt composite particles. In the high-temperature flue gas environment, the droplets rapidly lose water, and the dissolved salts become supersaturated. The magnetic salt composite particles are crystallized, coated, or co-precipitated on the surface of the magnetic seed crystals, ultimately forming magnetic salt composite particles with magnetic particles as the core and inorganic salts and heavy metal hydroxides as the outer layer. Step S4: The magnetic salt composite particles are captured and separated from the flue gas using magnetic force. A strong magnetic field is applied to the flue gas flow to selectively capture the magnetic salt composite particles, while the non-magnetic boiler fly ash continues to enter the dust collector and is collected separately. Step S5: The magnetic seed crystals are peeled off from the magnetic salt composite particles and recycled. The captured magnetic salt composite particles are cleaned, the soluble salts are dissolved, and then the pure magnetic seed crystals are extracted by a wet magnetic drum separator. Finally, they are sent back to the premixing module 1 for reuse through the return pipeline 43.

[0040] According to the present invention, the desulfurization wastewater flue gas drying treatment method introduces recyclable magnetic seed crystals into the desulfurization wastewater, utilizes the waste heat of high-temperature flue gas from the boiler to achieve evaporation and drying of the desulfurization wastewater, and uses magnetic field force to directionally separate pollutants (chlorides, sulfates, heavy metals, etc.) from the flue gas in the form of magnetic salt composite particles, ultimately achieving the regeneration and reuse of magnetic seed crystals, thereby achieving zero discharge of desulfurization wastewater, eliminating the need for additional evaporation and crystallization devices, saving energy and reducing consumption, reducing operating costs, and concentrating and enriching pollutants, which facilitates subsequent salt resource utilization or safe disposal.

[0041] In some embodiments of the present invention, the magnetic seed crystal is at least one of magnetite powder (Fe3O4), γ-Fe2O3, ferrite powder, iron-based alloy powder, or porous ceramic microspheres containing magnetic cores. For example, the magnetic seed crystal can be one of magnetite powder (Fe3O4), γ-Fe2O3, ferrite powder, iron-based alloy powder, or porous ceramic microspheres containing a magnetic core; the magnetic seed crystal can also be two of the following: magnetite powder (Fe3O4), γ-Fe2O3, ferrite powder, iron-based alloy powder, or porous ceramic microspheres containing a magnetic core; the magnetic seed crystal can also be three of the following: magnetite powder (Fe3O4), γ-Fe2O3, ferrite powder, iron-based alloy powder, or porous ceramic microspheres containing a magnetic core; the magnetic seed crystal can also be four of the following: magnetite powder (Fe3O4), γ-Fe2O3, ferrite powder, iron-based alloy powder, or porous ceramic microspheres containing a magnetic core; or the magnetic seed crystal can also be five of the following: magnetite powder (Fe3O4), γ-Fe2O3, ferrite powder, iron-based alloy powder, or porous ceramic microspheres containing a magnetic core.

[0042] In some embodiments of the present invention, the average particle size of the magnetic seeds is 5 μm-50 μm. It is understood that if the magnetic seed particle size is less than 5 μm, although it has a large specific surface area and high nucleation activity, it is prone to agglomeration to form secondary particles with poor dispersibility. It is difficult to be effectively captured by the magnetic separation device in high-speed flue gas, and it is easy to penetrate the dust removal / magnetic separation equipment, mixing with fly ash and causing chlorine pollution. If the magnetic seed particle size exceeds 50 μm, although it has a strong magnetic response and is easy to separate, it has a fast settling speed in the slurry, high stirring energy consumption, and is prone to uneven concentration. It is difficult to be completely wrapped by the droplets during atomization, causing the exposed particles to directly enter the flue 21, which cannot effectively bind salts. In addition, the drying time of large particles is prolonged, and they may settle before being completely dehydrated, causing scale or corrosion in the flue 21.

[0043] For example, the average particle size of magnetic seeds can be 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, etc.

[0044] Furthermore, the mass ratio of magnetic seed crystals to the theoretical amount of crystallizable salt in desulfurization wastewater is 1:5-1:20.

[0045] In some embodiments of the present invention, step S1 further includes adding an agglomeration aid to crosslink and agglomerate the fragments of the magnetic seed crystals with the salt microcrystals. This achieves preliminary particle construction in a liquid phase environment, which is more uniform and controllable than dry agglomeration within the flue 21. It avoids the free nucleation of salt microcrystals to form non-magnetic fine particles, reduces the generation of non-magnetic pollutants at the source, inhibits the independent growth of salt microcrystals into free fine powder, and ensures that pollutants are always bound to the magnetic carrier, facilitating moisture evaporation and preventing particle breakage.

[0046] Furthermore, the magnetic force in step S4 is 2000Gs-10000Gs. For example, the magnetic force can be 2000Gs, 2500Gs, 3000Gs, 3500Gs, 4000Gs, 4500Gs, 5000Gs, 5500Gs, 6000Gs, 6500Gs, 7000Gs, 7500Gs, 8000Gs, 8500Gs, 9000Gs, 9500Gs, 10000Gs, etc.

[0047] Furthermore, the surface velocity of the flue gas flowing through the magnetic separation module is 5m / s-15m / s. For example, the surface velocity of the flue gas flowing through the magnetic separation module can be 5m / s, 6m / s, 7m / s, 8m / s, 9m / s, 10m / s, 11m / s, 12m / s, 13m / s, 14m / s, 15m / s, etc.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0052] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A zero-discharge system for desulfurization wastewater induced by magnetic seed crystals (100), characterized in that, include: A premixing module (1) is used to mix and deliver slurry; Atomizing module (2), which is connected to the premixing module (1) and located downstream of the premixing module (1), is used to atomize the slurry; magnetic separation module (3), which is connected to the atomizing module (2) and located downstream of the atomizing module (2), is used to capture and separate magnetic particles; regeneration module (4), which is connected between the premixing module (1) and the regeneration module (4), is used to recover magnetic seeds.

2. The zero-discharge system for desulfurization wastewater based on magnetic seed induction according to claim 1 (100), characterized in that, The premixing module (1) includes a stirring tank (11), a magnetic seed feeding device (13), and a delivery pump (12). The stirring tank (11) and the delivery pump (12) are connected in sequence. The stirring tank (11) is used to stir and mix desulfurization wastewater and magnetic seeds. The magnetic seed feeding device (13) is used to feed magnetic seeds into the stirring tank (11). The delivery pump (12) is used to deliver the mixed slurry to the atomization module (2).

3. The zero-discharge system for desulfurization wastewater based on magnetic seed induction according to claim 2 (100), characterized in that, The atomizing module (2) includes a flue (21) and an atomizing gun (22). The flue (21) is connected to the stirring vessel (11) and the regeneration module (4), and the flue (21) is connected to the flue gas source (200). The atomizing gun (22) is located in the flue (21) to atomize the mixed slurry.

4. The zero-discharge system for desulfurization wastewater based on magnetic seed induction according to claim 1 (100), characterized in that, The regeneration module (4) includes: a discharge ash hopper (41), an ultrasonic cleaning tank (42), a wet magnetic drum separator (44), and a return pipeline (43). The ultrasonic cleaning tank (42) is used to treat the salt on the surface of the magnetic seed crystals. The wet magnetic drum separator (44) is used to extract the magnetic seed crystals. One end of the return pipeline (43) is connected to the wet magnetic drum separator (44), and the other end of the return pipeline (43) is connected to the premixing module (1).

5. The zero-discharge system for desulfurization wastewater based on magnetic seed induction according to claim 1 (100), characterized in that, Also includes: The detector and control module are provided. The detector is used to detect the chloride ion concentration in fly ash. The control module is electrically connected to the premixing module (1), the magnetic separation module (3) and the detector. The control module is used to control the premixing module (1), the magnetic separation module (3) and the detector.

6. A method for drying flue gas from desulfurization wastewater, characterized in that, The desulfurization wastewater zero-discharge system (100) based on magnetic seed induction according to any one of claims 1-5, the desulfurization wastewater flue gas drying treatment method includes: step S1, adding magnetic seed to the desulfurization wastewater to be treated and stirring to obtain a suspension slurry of magnetic seed; step S2, atomizing and spraying the suspension slurry into the flue; step S3, the high-temperature flue gas in the flue causes the water in the slurry to evaporate, so as to induce the impurities and salts in the desulfurization wastewater to adhere to the magnetic seed to form magnetic salt composite particles; step S4, using magnetic field force to capture and separate the magnetic salt composite particles from the flue gas; step S5, peeling the magnetic seed from the magnetic salt composite particles and recycling them.

7. The method for drying desulfurization wastewater and flue gas according to claim 6, characterized in that, The magnetic seed crystal is at least one of magnetite powder, γ-Fe2O3, ferrite powder, iron-based alloy powder, or porous ceramic microspheres with magnetic cores.

8. The method for drying desulfurization wastewater and flue gas according to claim 6, characterized in that, The average particle size of the magnetic seeds is 5μm-50μm.

9. The method for drying desulfurization wastewater and flue gas according to claim 6, characterized in that, Step S1 further includes adding an agglomeration aid to crosslink and agglomerate the fragments of the magnetic seed crystals with the salt microcrystals.

10. The method for drying desulfurization wastewater and flue gas according to claim 6, characterized in that, The magnetic field force in step S4 is 2000Gs-10000Gs.

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