A wastewater crystallization granulation fluidized bed treatment device and treatment method thereof

Abstract

The present invention discloses a wastewater crystallization granulation fluidized bed treatment device and a treatment method thereof. The wastewater crystallization granulation fluidized bed treatment device comprises a crystal seed delivery system, an alkali solution dosing system, a coagulation system, a sludge discharge system, a coarse particle collection system and a fluidized bed reactor. The crystallization granulation fluidized bed treatment device of the present invention adopts a variable diameter design so that the rising water velocity is distributed with the height, which facilitates the suspension of crystal seeds of different particle sizes, improves the utilization rate of the crystal seeds and the hardness removal efficiency, and has the functions of removing hardness and turbidity.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, in particular to a wastewater crystallization granulation fluidized bed treatment device and a treatment method thereof. Background Art

[0002] Industrial production produces a lot of wastewater, such as reverse osmosis concentrated water. Its treatment and reuse require the removal of hardness and turbidity. In addition, when using a crystallization granulation fluidized bed to remove hardness, a large amount of turbidity substances will also be produced. Usually, a combination of "chemical crystallization granulation fluidized bed" and "solid-liquid separation fluidized bed" is used to complete the task of removing hardness and turbidity (Ma Lu, Application of chemical crystallization granulation fluidized bed softening technology in deep treatment of reclaimed water, Chemical Engineering Design Communications, 2021, 47 (11): 86-86). At present, for wastewater treatment, there is an urgent need for integrated equipment with both hardness removal and turbidity removal functions. Chemical crystallization granulation fluidized bed can be used to remove hardness, heavy metals, fluorine, etc. from wastewater. It mainly uses reagents and crystal seeds to induce sediments to adhere to the crystal seeds using the principle of chemical deposition. The crystal seeds usually use mineral particles with high density, small particle size and large specific surface area. The crystal seeds have a certain particle size range, which is usually 60-100 mesh in practice. Seed crystals have a certain particle size range. When the rising water flow in the chemical crystallization fluidized bed is constant, coarse seed crystals are prone to precipitation and fine seed crystals are lost. Therefore, how to optimize the structure of the chemical crystallization granulation fluidized bed to ensure that all seed crystals are suspended and not lost is an urgent problem to be solved.

[0003] Among the existing patent applications, the patent application "A high-efficiency crystallization fluidized bed equipment" (application number 202410191422.5) adds partitions inside the fluidized bed and uses a multi-point water inlet method to divide the fluidization area of large and small crystal seeds, so that the water inlet and particles are evenly distributed; the patent application "A crystallization fluidized bed treatment device for high-hardness wastewater" (application number 201510864696.7) adopts an inner and outer cylinder structure, and uses the circulating water flow of the outer cylinder to impact the coarse-grained crystal seeds near the water distribution area, but the circulating water volume of the outer cylinder is limited, and the effective area is very small, which cannot solve the fundamental problem. The application has a small section of variable diameter structure at the bottom, but it is located below the water distribution area. Its purpose is to be used for pipeline layout and connection, and it does not help to change the flow state of the reactor; the patent application "Nuclear crystal condensation induced granulation water treatment device for simultaneous removal of high-valent ions and organic matter" (application number 202010278446.6), the crystallization fluidized bed also adopts an internal and external double-cylinder structure, and a solid-liquid separation inclined plate is set on the top to remove turbidity, and organic matter is removed by adding ozone; the patent application "A crystallization fluidized bed treatment device for high-hardness wastewater" (application number 201510864696.7) adds an inclined plate and an ozone pipe on this basis, and does not involve solving the suspension problem of coarse-grained crystal seeds; in addition, a solid-liquid separation inclined plate is set on the top of the cylinder, and the lower The settled sludge will mix with the seed crystals and contaminate the seed crystal surface; the patent application "A combined fluidized bed multifunctional water treatment system" (application number 202120594164.7) combines a chemical crystallization circulating granulation fluidized bed with a solid-liquid separation circulating granulation fluidized bed to achieve hardness and turbidity removal. The technical concept is the same as that in the literature (Ma Lu, Application of chemical crystallization granulation fluidized bed softening technology in deep treatment of reclaimed water, Chemical Engineering Design Communications, 2021, 47 (11): 86-86); the patent application "A crystallization fluidized bed treatment device for high-hardness wastewater" (application number 202122857047.8) uses a fluidized bed, a stirring tank and a sedimentation tank in series to soften the wastewater and remove suspended solids. The high-hardness wastewater is treated by fluidized bed softening and chemical coagulation and sedimentation. The equipment occupies a large area and the operation is relatively cumbersome.

[0004] Therefore, existing literature indicates that there are at least the following problems in wastewater treatment: (1) the problem of adding seeds within a certain particle size range to prevent the precipitation of coarse seeds and the loss of fine seeds; (2) the problem of an integrated device that can remove both hardness and turbidity while avoiding interference between the two; and (3) the problem of high sludge moisture content. Therefore, in response to the above technical problems, the present invention proposes a wastewater crystallization and granulation fluidized bed treatment device. Summary of the Invention

[0005] The present invention provides a wastewater crystallization granulation fluidized bed treatment device and a treatment method thereof, aiming to partially or completely solve the above-mentioned technical problems. The present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a wastewater crystallization and granulation fluidized bed treatment device, comprising a crystal seed feeding system, an alkali solution dosing system, a coagulation system, a sludge discharge system, a coarse particle collection system, and a fluidized bed reactor;

[0007] The seed feeding system includes a water inlet pump, a seed feeding hopper, a seed mixing hopper, a seed dosing pump, and a seed dosing pipe. The seed feeding hopper feeds the seeds into the seed mixing hopper through the seed dosing pipe, and the water inlet pump pumps water into the seed mixing hopper. After the water and seeds are fully mixed, they are pumped into the fluidized bed through the dosing pump to avoid seed blockage.

[0008] The alkali dosing system includes an alkali storage tank, an alkali pump, an alkali dosing control valve, and a claw-shaped alkali dosing pipe. The alkali storage tank, alkali pump, alkali dosing control valve, and claw-shaped alkali dosing pipe are connected in sequence. The alkali dosing control valve detects the pH value using a real-time online pH detector and uses feedback to control the amount of alkali added. The claw-shaped alkali dosing pipe is located at the center of a porous fixed disk and is divided into three branches. Each branch has a hole with a diameter of 1 mm. Alkali is added through the small hole to achieve uniform alkali dosing.

[0009] The sludge discharge system includes an inclined plate, a sludge discharge barrel, a sludge pump, and a sludge collection tank. The inclined plate, the sludge discharge barrel, the sludge pump, and the sludge collection tank are arranged in sequence, and the upper end of the inclined plate is an outlet overflow weir; the fluidized bed reactor includes a cylindrical outer cylinder, a water inlet pump, a pressure gauge, a porous fixed disk, a pagoda-shaped water distribution cap, a real-time online pH detector, and an online turbidity detector; the cylindrical outer cylinder, the water inlet pump, and the pressure gauge are connected in sequence, and the real-time online pH detector and the online turbidity detector are connected; through holes are distributed on the porous fixed disk for fixing the pagoda-shaped water distribution cap; the porous fixed disk has reserved holes for fixing the claw-shaped alkali solution dosing tube; the gap of the pagoda-shaped water distribution cap is 0.5mm, and the outlet water is provided with a real-time online pH detector and an online turbidity detector to realize the automation of softening and turbidity removal.

[0010] Optionally, the coagulation system includes a dosing tank, a dosing pump, a chemical dosing control valve, a chemical dosing pipe, a pipeline mixer, a guide plate, and a water outlet trough; the dosing tank, the dosing pump, the chemical dosing control valve, the chemical dosing pipe, and the pipeline mixer are connected in sequence; the chemical dosing control valve detects turbidity through an online turbidity detector, and feedback is processed to control the dosage of the flocculant; the chemical dosing pipe is arranged at the front end of the pipeline mixer, located on the central axis of the pipeline; the pipeline mixer is provided with front and rear porous plates for mixing the inlet and outlet water, and three groups of blades are arranged between the two plates for mixing the water and the flocculant; the guide plate is connected to the pipe wall at an angle of 45°; the coarse particle collection system includes a particle discharge valve and a particle collection bucket, and the particle discharge valve and the particle collection bucket are connected.

[0011] Optionally, the crystallization granulation fluidized bed treatment device includes a first wastewater treatment control coefficient D1 and a second wastewater treatment control coefficient D2. The first wastewater treatment control coefficient D1 and the second wastewater treatment control coefficient D2 are respectively: D1 = A1 / dA - A3 / dC, D2 = A1 / dA + A3 / dC - 2A2 / dB, satisfying: 1.15 < D1 < 2.15, 1.51 < D2 < 2.55. Wherein, dA is the diameter of the mixing area A of the lye and the influent at the bottom of the reactor, A1 is the flow velocity magnitude of the lye and the influent in the mixing area A at the bottom of the reactor, dB is the diameter of the middle area B in the upper part of the mixing area A, A2 is the flow velocity magnitude of the middle area B in the upper part of the mixing area A, dC is the diameter of the upper area C of the middle area B, and A3 is the flow velocity magnitude of the upper area C of the middle area B.

[0012] Optionally, at the bottom of the reactor, there is a mixing area A for the lye and the influent, with a diameter dA of the mixing area A; the upper part of the mixing area A is the middle area B, with a diameter dB of the middle area B, and the upper part of the middle area B is the area C, with a diameter of the area C satisfying: dA < dB < dC.

[0013] Optionally, the crystallization granulation fluidized bed treatment device includes: a third wastewater treatment control coefficient D3, and the third wastewater treatment control coefficient D3 is: D3 = dA 2 / dC 2 +dA 2 / dB 2 +dC 2 / dB 2 , satisfying: 1.6 < D3 < 4.1.

[0014] Optionally, the seed crystal is a garnet seed crystal, and the force balance formula of the seed crystal is: (Q crystal - Q water)πd 2 g / 3 = C D Q water(A2) 2 πd 2 / 8, particle Reynolds number: Re = Q crystal dA2 / μ, Q crystal and Q water respectively represent the densities of the seed crystal and water, with the unit kg / m 3 , d represents the diameter of the seed crystal, with the unit m; A2 represents the flow velocity in the middle area B, with the unit m / h; μ represents the liquid viscosity coefficient; C D represents the resistance coefficient, and is取值 according to the value of the particle Reynolds number Re;

[0015] When Re < 1, C D = 24 / Re;

[0016] When 1 < Re < 1000, C D = 30 / Re 0.625 ;

[0017] When Re > 1000, C​D =0.44.

[0018] In a second aspect, the present invention provides a wastewater treatment method, which uses the crystallization granulation fluidized bed treatment device described in any one of the first aspects above, comprising the following steps:

[0019] Step S100: The total height of the fluidized bed equipment is 4.5m, and the height of the coagulation and settling end is 1.5m. The diameter of the alkali solution and influent mixing area A at the bottom of the reactor is dA, the diameter of the middle area B above it is dB, and the diameter of the upper area C is dC. The wastewater passes through the pagoda-shaped water distribution cap on the porous fixed disk. The water distribution cap is distributed with 0.5mm gaps to ensure that the influent water is evenly distributed into the fluidized bed tube. The influent water is adjusted so that the flow rate of area B is A2m / h, the flow rate of area A is A1m / h, and the flow rate of area C is A3m / h, which can ensure that 60-80 mesh particles will not overflow.

[0020] Step S200: NaOH is added to the fluidized bed via a dosing pump. The dosing pipe is independent of the fluidized bed and connected to the center of the porous fixed plate. A claw-shaped alkali solution dosing pipe is connected to the pipe. Holes with a diameter of 1 mm are provided on the three branch pipes for distributing the alkali solution, ensuring uniform contact between the alkali solution and the influent water. The pH value of the effluent water is controlled to be 10.5-10.9.

[0021] Step S300: Add 60-80 mesh garnet to a seed crystal feeding hopper, which is connected to a seed crystal mixing hopper via a conveyor belt; a water inlet pump pumps water into the seed crystal mixing hopper, and after the water and seed crystals are fully mixed, the water is pumped into the fluidized bed via a feeding pump to prevent seed crystal blockage; as the crystals grow larger as the crystals crystallize, a seed crystal discharge pipe is opened to discharge the coarse particles into a collection tank;

[0022] Step S400: The softened wastewater mixed with Mg(OH)2 flocs rises to the coagulation area, the flocculant control valve is opened, and the flocculant is added to the front end of the pipeline mixer through the agent dosing pipe, mixed with water and enters the pipeline mixer; the mixed water is dispersed through the guide plate; the flocs in the sedimentation area fall into the sludge collection bucket; the clean water overflows to the outlet trough for collection, thereby completing the wastewater treatment.

[0023] Optionally, for wastewater with a total hardness of 2000 mg / L CaCO3 and a total alkalinity of 900 mg / L, wherein the Mg content is 110 mg / L, after steps S100 to S400, the total hardness and CaCO3 of the effluent are 2+ Mg 2+ The concentrations are 315.98 mg / L, 78.43 mg / L and 28.23 mg / L respectively, and the effluent turbidity is 2 NTU, and the discharged sludge moisture content is 85%; or, for wastewater with a total hardness of 4000 mg / LCaCO3 and a total alkalinity of 120 mg / L, the Mg 2+The content is 300 mg / L. After steps S100 to S400, the total hardness of the effluent, the concentrations of Ca 2+ , Mg 2+ are 394.97 mg / L, 94.11 mg / L and 37.64 mg / L respectively, and the turbidity of the effluent is 3.6 NTU, and the moisture content of the discharged sludge is 85%. Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] (1) By designing reaction zones with different diameters, different upward flow velocities are obtained in the fluidized bed, so that different particle-size crystal seeds can be suspended. In the mixing zone A of the lye and influent water at the bottom of the reactor, a smaller diameter dA is adopted to increase the upward water velocity to avoid the accumulation of crystal seeds at the bottom, thereby improving the utilization rate of crystal seeds; in addition, with a large flow velocity and a high degree of turbulence, it is convenient for the mixing between water and lye. Above it is the middle zone B, with a slightly larger diameter dB and a slightly larger upward water velocity to suspend the crystal seeds of the middle particle size. The upper part is zone C, with the largest diameter dC and a further reduced flow velocity to avoid the overflow of small-particle crystal seeds resulting in insufficient crystal seeds. The relationship between the diameters of the three zones is dA < dB < dC. According to the particle-size range, density of the crystal seeds, and wastewater treatment, the values of dA, dB, and dC can be quantitatively determined; through the variable-diameter design, the upward water velocity is distributed along the height, which is convenient for the suspension of crystal seeds with different particle sizes, improving the utilization rate of crystal seeds and the hardness removal efficiency; an integrated device that has both the functions of removing hardness and turbidity and avoids their mutual interference reduces the floor area and is convenient for automatic control;

[0025] (2) The ranges of the first wastewater treatment control coefficient D1, the second wastewater treatment control coefficient D2, and the third wastewater treatment control coefficient D3 are used to avoid the situation where the flow velocity of the water flow is too small (even 0) in the transition zone AB between zone A and zone B and the transition zone BC between zone B and zone C due to too small dA and too large dC. At the same time, it can also avoid the decrease in the overall structural strength of the crystallization granulation fluidized bed treatment device. By controlling the diameters of zone A, zone B, and zone C, it is possible to prevent the sizes of zone A, zone B, and zone C from being too large or too small, and also appropriately control the cost of the crystallization granulation fluidized bed treatment device;

[0026] (3) An overflow weir is set at the top of the crystallization granulation fluidized bed, and a drainage pipe is set up. A pipeline mixer is placed in the pipe, and the flocculant dosing pipe is connected to the pipe, and then mixed with water through the pipeline mixer; the water flows downward, encounters the baffle, and then flows upward to enter the sludge sedimentation area. An inclined plate / pipe is set at the top of the sedimentation area to enhance solid-liquid separation; the clean water passes through the inclined plate / pipe and is discharged to the outside. The discharge pipe is equipped with an online pH value and turbidity detector, and the data is fed back to the PCL controller to control the amount of alkali solution and flocculant added; a high water column and small cone angle design scheme is adopted to enhance the compression of the sludge, thereby reducing the sludge water content, achieving a high turbidity removal rate and a low sludge water content, and realizing the integrated treatment of high turbidity and high hardness wastewater with both hardness removal and turbidity removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of a wastewater crystallization and granulation fluidized bed treatment device applied for by the present invention;

[0028] Figure 2 This is a partial structural diagram of the fluidized bed reactor of the alkali solution dosing system applied for in the present invention;

[0029] Figure 3 This is a partial structural diagram of a wastewater crystallization and granulation fluidized bed treatment device applied for by the present invention;

[0030] Figure 4 This is a partial structural diagram of the coagulation system applied for in the present invention;

[0031] Figure numerals: 11-water inlet pump, 12-seed feeding bucket, 13-seed mixing bucket, 14-seed dosing pump, 15-seed dosing pipe; 21-alkali storage tank, 22-alkali solution pump, 23-alkali solution dosing control valve, 24-claw-shaped alkali solution dosing pipe; 31-dosing tank, 32-dosing pump, 33-agent dosing control valve, 34-agent dosing pipe, 35-pipeline mixer, 36-guide plate, 37-water outlet trough; 41-inclined plate, 42-sludge discharge cylinder, 43-sludge pump, 44-sludge collection tank; 51-particle discharge valve, 52-particle collection bucket; 61-cylindrical outer cylinder, 62-water inlet pump, 63-pressure gauge, 64-porous fixed plate, 65-pagoda-shaped water distribution cap, 66-pH value real-time online detector, 67-online turbidity detector.

[0032] As shown in the figure, in order to clearly implement the structure of the embodiment of the present invention, specific structures and devices are marked in the figure, but this is only for illustrative purposes and is not intended to limit the present invention to the specific structure, device and environment. According to specific needs, ordinary technicians in this field can adjust or modify these devices and environments, and the adjustments or modifications made are still included in the scope of the appended claims. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It is also noted that, to provide a more detailed description, the following embodiments are best and preferred embodiments, and those skilled in the art may employ alternative implementations for certain known technologies. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.

[0034] First, as Figure 1-4 As shown, the present invention is a fluidized bed treatment device for crystallization and granulation of wastewater, comprising a seed feeding system, an alkali solution dosing system, a coagulation system, a sludge discharge system, a coarse particle collection system and a fluidized bed reactor;

[0035] The seed feeding system includes a water inlet pump 11, a seed feeding hopper 12, a seed mixing hopper 13, a seed dosing pump 14, and a seed dosing pipe 15. The seed feeding hopper 12 feeds the seed crystals into the seed mixing hopper 13 through the seed dosing pipe 15. The water inlet pump 11 pumps water into the seed mixing hopper 13. After the water and seed crystals are fully mixed, they are pumped into the fluidized bed through the dosing pump 14 to avoid seed crystal blockage.

[0036] The alkali solution dosing system includes an alkali solution storage tank 21, an alkali solution pump 22, an alkali solution dosing control valve 23, and a claw-shaped alkali solution dosing pipe 24, which are connected in sequence. The alkali solution dosing control valve 23 detects the pH value using a real-time online pH detector 66 and uses feedback processing to control the amount of alkali solution added. The claw-shaped alkali solution dosing pipe 24 is located at the center of a porous fixed disk 64 and has three branches. Each branch has a hole with a diameter of 1 mm. Alkali solution is added through the small hole to achieve uniform dosing of the alkali solution.

[0037] The coagulation system includes a dosing tank 31, a dosing pump 32, a drug dosing control valve 33, a drug dosing pipe 34, a pipeline mixer 35, a guide plate 36, and a water outlet trough 37. The dosing tank 31, the dosing pump 32, the drug dosing control valve 33, the drug dosing pipe 34, and the pipeline mixer 35 are connected in sequence; the drug dosing control valve 33 detects turbidity through an online turbidity detector 67, and controls the dosage of flocculant through feedback processing; the drug dosing pipe 34 is arranged at the front end of the pipeline mixer 35, located on the central axis of the pipeline; the pipeline mixer 35 is provided with front and rear porous plates for mixing inlet and outlet water, and three sets of blades are arranged between the two plates for mixing water and flocculant; the guide plate 36 is connected to the pipe wall at an angle of 45°. The function of the guide plate 36 is to guide the descending water flow to prevent the water flow from impacting the bottom sludge;

[0038] The sludge discharging system may include multiple groups, and only one group is schematically shown in the figure. The sludge discharging system includes an inclined plate 41, a sludge discharging cylinder 42, a sludge pump 43, and a sludge collection tank 44. The inclined plate 41, the sludge discharging cylinder 42, the sludge pump 43, and the sludge collection tank 44 are arranged correspondingly in sequence. The upper end of the inclined plate 41 is an effluent overflow weir; the coarse particle collection system includes a particle discharge valve 51 and a particle collection hopper 52, and the particle discharge valve 51 and the particle collection hopper 52 are connected; the fluidized bed reactor includes a cylindrical outer cylinder 61, a water inlet pump 62, a pressure gauge 63, a porous fixed plate 64, and a pagoda-shaped water distribution cap 65. The cylindrical outer cylinder 61, the water inlet pump 62, and the pressure gauge 63 are connected in sequence. The pH value real-time online detector 66 and the online turbidity detector 67 are connected; through holes are distributed on the porous fixed plate 64 for fixing the pagoda-shaped water distribution cap 65, and the pagoda-shaped water distribution cap 65 is used for uniform water distribution; a claw-shaped lye dosing pipe 24 is reserved and fixed in the hole of the porous fixed plate 64; the gap of the pagoda-shaped water distribution cap 65 is 0.5 mm, so as to make the inlet water distribution uniform and avoid the settlement of crystal seeds at the bottom of the fluidized bed; the effluent enters the sludge discharging system through the pipeline mixer 35 of the coagulation system, and the pH real-time online detector 66 and the online turbidity detector 67 are arranged for the effluent to realize the automation of softening and turbidity removal.

[0039] Optionally, in the alkali liquid and influent mixing region A at the bottom of the reactor, the diameter dA of the mixing region A; the upper part of the mixing region A is the intermediate region B, the diameter dB of the intermediate region B, and the upper part of the intermediate region B is the region C, the diameter of the region C is, satisfying: dA < dB < dC.

[0040] In the application of the present invention, in the alkali liquid and influent mixing region A at the bottom of the reactor, generally a smaller diameter dA is adopted to increase the upward water velocity, so as to avoid the accumulation of crystal seeds at the bottom, form a fixed layer and not participate in fluidization, thereby improving the utilization rate of crystal seeds; in addition, with a large flow velocity and a high degree of turbulence, it is convenient for the mixing between water and alkali liquid. Its upper part is the intermediate region B, with a slightly larger diameter dB. Generally speaking, the upward water velocity is slightly larger to make the intermediate-sized crystal seeds suspended. The upper part is the region C, with the largest diameter dC. Generally speaking, the flow velocity further becomes smaller to avoid the overflow of small-sized crystal seeds and cause insufficient crystal seeds. The relationship between the diameters of the three regions is dA < dB < dC. According to the crystal seed particle size range, density, and wastewater treatment, the values of dA, dB, and dC can be quantitatively determined; through the variable diameter design, the upward water velocity is distributed along the height, which is convenient for crystal seeds of different particle sizes to be suspended, improves the utilization rate of crystal seeds and the hardness removal efficiency, has the functions of removing hardness and turbidity, and avoids the mutual interference between the two. The integrated equipment reduces the floor area and is convenient for automatic control.

[0041] Based on the diameter dA of the lye and influent mixing area A (which can be simply referred to as area A) at the bottom of the above reactor, the diameter dB of the upper middle area B (which can be simply referred to as area B) of the mixing area A, and the diameter dC of the upper area C (which can be simply referred to as area C) of the middle area B, although the relationship between the diameters of the three areas satisfies: dA < dB < dC, different particle-size seeds can be suspended. However, specifically how to achieve the control of the suspension effect of different particle-size seeds, the applicant has conducted further technical research based on diameter, flow rate, flow velocity, etc. to meet different suspension requirements of the seeds.

[0042] Optionally, the crystallization granulation fluidized bed treatment device includes a first wastewater treatment control coefficient D1 and a second wastewater treatment control coefficient D2. The first wastewater treatment control coefficient D1 and the second wastewater treatment control coefficient D2 are respectively: D1 = A1 / dA - A3 / dC, D2 = A1 / dA + A3 / dC - 2A2 / dB, and satisfy: 1.15 < D1 < 2.15, 1.51 < D2 < 2.55, where dA is the diameter of the lye and influent mixing area A at the bottom of the reactor, A1 is the flow velocity magnitude of the lye and influent mixing area A at the bottom of the reactor, dB is the diameter of the upper middle area B of the mixing area A, A2 is the flow velocity magnitude of the upper middle area B of the mixing area A, dC is the diameter of the upper area C of the middle area B, and A3 is the flow velocity magnitude of the upper area C of the middle area B, with the unit of m / s.

[0043] In the present invention application, the crystallization granulation fluidized bed treatment device includes a first wastewater treatment control coefficient D1 and a second wastewater treatment control coefficient D2. The first wastewater treatment control coefficient D1 and the second wastewater treatment control coefficient D2 can correlate the flow velocity magnitude and the diameters of different areas, thereby meeting different suspension requirements of the seeds.

[0044] In the present invention application, the first wastewater treatment control coefficient D1 is usually kept within a reasonable range, which can ensure that the flow velocities of area A and area C differ significantly and appropriately, satisfying: 1.15 < D1 < 2.15. The flow velocity A1 of area A will differ significantly from the flow velocity A3 of area C, which can ensure a high degree of turbulence in area A, facilitating the mixing between water and lye, and preventing small-particle seeds from overflowing in area C. Of course, the first wastewater treatment control coefficient D1 cannot be too large or too small, so as to avoid making the flow velocity of area A infinitely large and the flow velocity of area C infinitely small. When the first wastewater treatment control coefficient D1 is too small, the flow velocity difference between area A and area C will be small. In area A, the flow velocity may not be sufficient to fully fluidize large particles, and in area C, the flow velocity may not be able to retain the rising small particles well. When the first wastewater treatment control coefficient D1 is too large, there is also a risk of reducing the particle treatment efficiency in the crystallization granulation fluidized bed treatment device, and the treated particles cannot settle, making particle discharge difficult.

[0045] In the application of the present invention, the second wastewater treatment control coefficient D2 is usually made to be within a reasonable range, so as to ensure that the flow velocities of regions A, B, and C are appropriately different. The flow velocity A1 of region A will be appropriately different from the flow velocity A2 of region B, and the flow velocity A1 of region B will be appropriately different from the flow velocity A2 of region C, which can ensure that the flow velocities of regions A, B, and C are overall matched and set, jointly ensuring the treatment efficiency and treatment results of wastewater. When the second wastewater treatment control coefficient D2 is too small, that is, the difference between the flow velocity difference between regions A and B and the flow velocity difference between regions B and C is small, which correspondingly may mean that the flow velocities of regions A, B, and C may be almost the same, and then it may be impossible to achieve the flow velocity difference between regions A, B, and C; when the second wastewater treatment control coefficient D2 is too large, the difference between the flow velocity difference between regions A and B and the flow velocity difference between regions B and C is large, which correspondingly may mean that the flow velocities of regions A and B may not be very different, or the flow velocities of regions B and C may not be very different, and it may be in the transition region AB between regions A and B or the transition region BC between regions B and C where the flow velocity of the water is too small (even 0), resulting in the accumulation of crystal seeds and being unable to participate in the reaction.

[0046] Therefore, in the application of the present invention, in the case of dA < dB < dC, by using the first wastewater treatment control coefficient D1 and the second wastewater treatment control coefficient D2, the flow velocities A1 of region A, A2 of region B, and A3 of region C can overall satisfy a reasonable relationship design, which can be to control the different suspensions of crystal seeds, thereby ensuring the wastewater treatment efficiency and wastewater treatment control results of the crystallization granulation fluidized bed treatment device.

[0047] Optionally, the crystallization granulation fluidized bed treatment device includes: a third wastewater treatment control coefficient D3, and the third wastewater treatment control coefficient D3 is: D3 = dA 2 / dC 2 +dA 2 / dB 2 +dC 2 / dB 2 , satisfying: 1.6 < D3 < 4.1.

[0048] In the application of the present invention, in the case of dA < dB < dC, the first wastewater treatment control coefficient D1 and the second wastewater treatment control coefficient D2, a third wastewater treatment control coefficient D3 can also be set to avoid the situation where dA is too small and dC is too large, and the flow velocity of the water flow in the transition region AB between region A and region B and the transition region BC between region B and region C is too small (even 0). At the same time, it can also avoid the decrease in the overall structural strength of the crystallization granulation fluidized bed treatment device. By controlling the diameters of region A, region B, and region C, it is possible to prevent the sizes of region A, region B, and region C from being too large or too small, and also appropriately control the cost of the crystallization granulation fluidized bed treatment device.

[0049] In the application of the present invention, for the different flow rates and flow velocities required in the lye and influent mixing region A at the bottom of the reactor, the upper middle region B of the mixing region A, and the upper region C of the middle region B, through the force analysis of the crystal seeds in the upper middle region B of the mixing region A, it is ensured that the crystal seeds in the upper middle region B of the mixing region A are in a suspended state, and the gravity buoyancy and motion resistance of the crystal seeds are balanced.

[0050] Optionally, the force balance formula for the crystal seeds is: (Q crystal - Q water)πd 2 g / 3 = C D Q water (A2) 2 πd 2 / 8, particle Reynolds number: Re = Q crystal dA2 / μ, where Q crystal and Q water respectively represent the densities of the crystal seeds and water, in kg / m 3 , d represents the diameter of the crystal seeds, in m; A2 represents the flow velocity in the middle region B, in m / h; μ represents the viscosity coefficient of the liquid; C D represents the resistance coefficient, which is taken according to the value of the particle Reynolds number Re;

[0051] When Re < 1, C D = 24 / Re;

[0052] When 1 < Re < 1000, C D = 30 / Re 0.625 ;

[0053] When Re > 1000, C D = 0.44.

[0054] In the application of the present invention, for garnet crystal seeds with a mesh size of 60 - 80, the flow velocity A2 in the middle region B can be selected as 60 - 100 m / h. Then, according to the treatment flow rate in region B, the diameter dB of the middle region B is determined. Then, according to the first wastewater treatment control coefficient D1, the second wastewater treatment control coefficient D2, and the third wastewater treatment control coefficient D3, appropriate diameters dA and dC can be selected according to D1, D2, and D3.

[0055] In some embodiments, the wastewater treatment flow rate of the crystallization and granulation fluidized bed treatment device can be selected as 9 cubic meters per hour, and the flow rate A2 of area B can be calculated or selected as 80 m / h (after a period of operation, the flow rate can be increased according to the growth of the seed crystal particle size). The diameter of the middle area B is obtained as dB=0.38 m, and the first wastewater treatment control coefficient D1=1.75 and the second wastewater treatment control coefficient D2=1.67 are selected to obtain:

[0056] A1 / dA-A3 / dC=D1

[0057] A1 / dA+A3 / dC-2A2 / dB=D2

[0058] dA 2 / dC 2 +dA 2 / dB 2 +dC 2 / dB 2 =D3

[0059] According to πA1dA 2 / 4=πA2dB 2 / 4=πA3dC 2 / 4, we can calculate:

[0060] dA=0.29m, dC=0.60m, A1=136m / h, A3=32m / h;

[0061] After calculation in the unit of flow velocity m / s, the corresponding results are: dA=0.12m, dB=0.38m, dC=0.60m, A1=764m / h, A2=80m / h, A3=32m / h, all of which are within the range of the first wastewater treatment control coefficient D1, the second wastewater treatment control coefficient D2 and the third wastewater treatment control coefficient D3.

[0062] In some embodiments, by substituting A1 and A3 into the force balance formula of the seed crystal, it can be obtained that A1 satisfies the suspension of the seed crystal with a diameter of 2 mm, and A3 can prevent the overflow of the particles with a diameter of 0.15 mm.

[0063] In a second aspect, the present invention also provides a wastewater treatment method, which uses any one of the wastewater crystallization and granulation fluidized bed treatment devices of the first aspect, and includes the following steps:

[0064] Step S100: The total height of the fluidized bed equipment is 4.5m, and the height of the coagulation and sedimentation end is 1.5m. The diameter of the alkali solution and influent mixing area A at the bottom of the reactor is dA, the diameter of the middle area B above it is dB, and the diameter of the upper area C is dC. The wastewater passes through the pagoda-shaped water distribution cap 65 on the porous fixed disk 64. The water distribution cap has 0.5mm gaps to evenly distribute the influent into the fluidized bed tube. The influent is adjusted so that the flow rate of area B is A2m / h, the flow rate of area A is A1m / h, and the flow rate of area C is A3m / h, which can ensure that 60-80 mesh particles will not overflow.

[0065] Step S200: NaOH is added to the fluidized bed via a dosing pump. The dosing pipe is independent of the fluidized bed and connected to the center of the porous fixed plate. A claw-shaped alkali solution dosing pipe is connected to the pipe. Holes with a diameter of 1 mm are provided on the three branch pipes for distributing the alkali solution, ensuring uniform contact between the alkali solution and the influent water. The pH value of the effluent water is controlled to be 10.5-10.9.

[0066] Step S300: Add 60-80 mesh garnet to a seed crystal feeding hopper, which is connected to a seed crystal mixing hopper via a conveyor belt; a water inlet pump pumps water into the seed crystal mixing hopper, and after the water and seed crystals are fully mixed, the water is pumped into the fluidized bed via a feeding pump to prevent seed crystal blockage; as the crystals grow larger as the crystals crystallize, a seed crystal discharge pipe is opened to discharge the coarse particles into a collection tank;

[0067] Step S400: The softened wastewater mixed with Mg(OH)2 flocs rises to the coagulation area, the flocculant control valve is opened, and the flocculant is added to the front end of the pipeline mixer through the agent dosing pipe, mixed with water and enters the pipeline mixer; the mixed water is dispersed through the guide plate; the flocs in the sedimentation area fall into the sludge collection bucket; the clean water overflows to the outlet trough for collection, thereby completing the wastewater treatment.

[0068] In some embodiments, for wastewater with a total hardness of 2000 mg / L CaCO3 and a total alkalinity of 900 mg / L, the Mg content is 110 mg / L. The specific implementation scheme is as follows:

[0069] The total height of the fluidized bed equipment is 4.5m, and the height of the coagulation and sedimentation end is 1.5m. By designing reaction areas of different diameters, different rising flow rates are achieved in the fluidized bed, thereby suspending crystal seeds of different particle sizes. The diameter of the alkali solution and water mixing area A at the bottom of the reactor is 120mm, and its upper part is the middle area. The diameter of the middle area B is 350mm. The upper part of the middle area B is area C, and the diameter of area C is 450mm. The wastewater passes through the pagoda-shaped water distribution cap 65 on the porous fixed disk 64. The water distribution cap is distributed with 0.5mm gaps, so that the water is evenly dispersed into the fluidized bed tube. The water is adjusted so that the flow rate of area B is 80m / h, the flow rate of area C is 48m / h, and the flow rate of area A is 680m / h, which can ensure that 60-80 mesh particles will not overflow.

[0070] The NaOH reagent is added to the fluidized bed via a dosing pump 22. The dosing pipe, independent of the fluidized bed, connects to the center of the porous fixed disk. This pipe is connected to a claw-shaped lye dosing pipe 23. Three branches are provided with 1mm diameter holes to distribute the lye, ensuring uniform contact between the lye and the influent. The effluent pH is controlled at 10.5-10.9.

[0071] Add 60-80 mesh garnet to the seed crystal feeding hopper 12, which is connected to the seed crystal mixing hopper 13 via a conveyor belt. A water inlet pump 11 pumps water into the seed crystal mixing hopper 13. After the water and seed crystals are thoroughly mixed, the water is pumped into the fluidized bed via a feeding pump 14 to prevent seed crystal clogging. As the crystals grow larger as the crystals crystallize, the seed crystal discharge pipe 51 is opened, and the coarse particles are discharged into a collection tank 52.

[0072] Softened water mixed with Mg(OH)2 flocs rises to the coagulation zone. The flocculant control valve 33 is opened, and the flocculant is added to the front end of the pipeline mixer through the agent injection pipe 34. It mixes with the water and enters the pipeline mixer 35. The mixed water is dispersed by the guide plate 36. The flocs in the sedimentation zone fall into the sludge collection hopper 42. The clean water overflows and is collected in the outlet trough 37; the total hardness and Ca content of the outlet water are calculated. 2+ Mg 2+ The concentrations were 315.98 mg / L, 78.43 mg / L and 28.23 mg / L respectively, the effluent turbidity was 2 NTU, and the moisture content of the discharged sludge was 85%.

[0073] In some embodiments, for wastewater with a total hardness of 4000 mg / LCaCO3 and a total alkalinity of 120 mg / L, Mg 2 + The content is 300mg / L. The specific implementation plan is as follows:

[0074] The total height of the fluidized bed equipment is 4.5m, with the coagulation and settling end at a height of 2.5m. The wastewater in this area has a high Mg2+ content, producing a large number of flocs. Extending the settling end helps reduce effluent turbidity. By designing reaction zones of varying diameters, the fluidized bed equipment achieves varying upward flow rates within the fluidized bed, thereby suspending seed crystals of varying particle sizes. The diameter of the alkali solution and influent mixing zone A at the bottom of the reactor is 160mm. Above this zone is the middle zone, with a diameter of 550mm. Above this zone is zone C, with a diameter of 750mm. Wastewater from zone C passes through a pagoda-shaped water distribution cap 65 on a porous fixed disk 64. The cap has 0.5mm gaps, ensuring uniform distribution of the influent water within the fluidized bed. The influent flow rate is adjusted to 80m / h in zone B, 43m / h in zone C, and 943m / h in zone A, ensuring that 60-80 mesh particles do not overflow.

[0075] According to the analysis of water hardness and alkalinity, NaOH and NaCO3 are selected as reagents to supplement carbonate to strengthen Ca 2+ The pH value of the effluent is controlled at 10.5-10.9.

[0076] 60-80 mesh garnet is added to the seed crystal feeding hopper 12, which is connected to the seed crystal mixing hopper 13 via a conveyor belt. A water inlet pump 11 pumps water into the seed crystal mixing hopper 13. After the water and seed crystals are thoroughly mixed, the water is pumped into the fluidized bed via a feeding pump 14 to prevent seed crystal clogging. As the crystals grow larger as the crystals crystallize, the seed crystal discharge pipe 51 is opened, and the coarse particles are discharged into a collection tank 52.

[0077] Softened water mixed with Mg(OH)2 flocs rises to the coagulation zone. The flocculant control valve 33 is opened and the flocculant is added to the front end of the pipeline mixer through the agent injection pipe 34. It mixes with water and enters the pipeline mixer 35. The mixed water is dispersed by the guide plate 36. The flocs in the sedimentation zone fall into the sludge collection hopper 42. The clean water overflows to the outlet trough 37 for collection. The total hardness and Ca content of the effluent are 2+ Mg 2+ The concentrations were 394.97 mg / L, 94.11 mg / L and 37.64 mg / L respectively, the effluent turbidity was 3.6 NTU, and the moisture content of the discharged sludge was 85%.

[0078] In the present application, by designing reaction areas of different diameters, different rising flow rates are achieved in the crystallization and granulation fluidized bed treatment device for wastewater, thereby suspending crystal seeds of different particle sizes, improving the utilization rate of the crystal seeds and the hardness removal efficiency; the integrated equipment has the functions of removing hardness and turbidity and avoids mutual interference between the two, reduces the floor space and facilitates automatic control; a water overflow weir is set on the top of the crystallization and granulation fluidized bed, a drainage pipe is set, a pipeline mixer is placed in the pipe, and a flocculant dosing pipe is connected to the pipe, and then mixed with water through the pipeline mixer; water flows downward, encounters a baffle, and then flows upward to enter the sludge sedimentation area. An inclined plate / pipe is set on the top of the sedimentation area to enhance solid-liquid separation; the clean water passes through the inclined plate / pipe and is discharged to the outside, and the external discharge pipe is equipped with a pH value and turbidity online detector, and the data is fed back to the PCL controller to control the dosage of alkali solution and flocculant, thereby realizing the integrated treatment of high turbidity and high hardness wastewater with both hardness and turbidity removal.

[0079] The present invention encompasses any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details.

[0080] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A wastewater crystallization and granulation fluidized bed treatment device, comprising a seed crystal feeding system, an alkali solution dosing system, a coagulation system, a sludge discharge system, a coarse particle collection system, and a fluidized bed reactor; The seeding system includes a water inlet pump, a seeding hopper, a seed mixing hopper, a seeding pump, and a seeding pipe; the fluidized bed reactor includes a connected cylindrical outer cylinder, a water inlet pump, a pressure gauge, a porous fixing plate, a pagoda-shaped water distribution cap, a real-time online pH value detector, and an online turbidity detector; the porous fixing plate is provided with through holes for fixing the pagoda-shaped water distribution cap; the coagulation system includes a dosing tank, a dosing pump, a reagent dosing control valve, a reagent dosing pipe, and a pipeline mixer, which are connected in sequence; The crystallization granulation fluidized bed treatment device includes a first wastewater treatment control coefficient D1, a second wastewater treatment control coefficient D2 and a third wastewater treatment control coefficient D3. The first wastewater treatment control coefficient D1, the second wastewater treatment control coefficient D2 and the third wastewater treatment control coefficient D3 are respectively: D1=A1 / dA-A3 / dC, D2=A1 / dA+A3 / dC-2A2 / dB, D3=dA 2 / dC 2 +dA 2 / dB 2 +dC 2 / dB 2 Satisfied: dA <dB<dC,1.15<D1<2.15,1.51<D2<2.55,1.6<D3<4.1; dA is the diameter of the alkali solution and influent mixing area A at the bottom of the reactor, A1 is the flow rate of the alkali solution and influent mixing area A at the bottom of the reactor, dB is the diameter of the upper middle area B of the mixing area A, A2 is the flow rate of the upper middle area B of the mixing area A, dC is the diameter of the upper area C of the middle area B, and A3 is the flow rate of the upper area C of the middle area B; The seed crystal is garnet seed crystal, and the force balance formula of the seed crystal is: (Q crystal - Q water)πd 2 g / 3=C D Q water (A2) 2 πd 2 / 8, particle Reynolds number: Re = Qcrystal dA2 / μ, Qcrystal, Qwater are the densities of seed crystal and water respectively, unit is kg / m 3 , d represents the diameter of the seed crystal, in m; A2 represents the flow rate in the middle region B, in m / h; μ represents the viscosity coefficient of the liquid; C D Represents the drag coefficient, which is determined according to the particle Reynolds number Re; When Re<1, C D =24 / Re; When 1 < Re < 1000, C D = 30 / Re 0.625 ; When Re>1000, C D =0.

44.

2. A wastewater crystallization granulation fluidized bed treatment device according to claim 1, characterized in that: The seed feeding bucket feeds the seed crystals into the seed mixing bucket through the seed crystal feeding pipe, and the water inlet pump pumps water into the seed crystal mixing bucket. After the water and seed crystals are fully mixed, they are pumped into the fluidized bed through the feeding pump to avoid seed crystal blockage; the alkali solution dosing system includes an alkali storage tank, an alkali solution pump, an alkali solution dosing control valve, and a claw-shaped alkali solution dosing pipe; the alkali storage tank, the alkali solution pump, the alkali solution dosing control valve, and the claw-shaped alkali solution dosing pipe are connected in sequence; the sludge discharge system includes an inclined plate, a sludge discharge cylinder, a sludge pump, and a sludge collection tank. The inclined plate, the sludge discharge cylinder, the sludge pump, and the sludge collection tank are arranged in sequence, and the upper end of the inclined plate is an outlet overflow weir; the alkali solution dosing control valve detects the pH value through a pH real-time online detector, and feedback is processed to control the amount of alkali solution added; the claw-shaped alkali solution dosing pipe is arranged in the center of the porous fixed disk, and the claw-shaped alkali solution dosing pipe is divided into three branches. A hole with a diameter of 1mm is set on it, and alkali solution is added through the small hole to achieve uniform addition of alkali solution; the chemical dosing control valve detects turbidity through an online turbidity detector, and feedback is processed to control the dosage of flocculant; the chemical dosing pipe is set at the front end of the pipeline mixer, located on the central axis of the pipeline; the pipeline mixer is provided with front and rear porous plates for mixing inlet and outlet water, and three sets of blades are set between the two plates for mixing water and flocculant; the guide plate is connected to the pipe wall with an angle of 45°; the coarse particle collection system includes a particle discharge valve and a particle collection bucket, and the particle discharge valve and the particle collection bucket are connected; the outlet water is provided with a real-time online pH detector and an online turbidity detector to realize the automation of softening and turbidity removal; the porous fixing plate has reserved holes to fix the claw-shaped alkali solution dosing pipe; the gap of the pagoda-shaped water distribution cap is 0.5mm.

3. A wastewater treatment method, which uses the crystallization granulation fluidized bed treatment device according to claim 2, characterized in that: The following steps are involved: Step S100: The total height of the fluidized bed equipment is 4.5m, and the height of the coagulation and settling end is 1.5m. The diameter of the alkali solution and influent mixing area A at the bottom of the reactor is dA, the diameter of the middle area B above it is dB, and the diameter of the upper area C is dC. The wastewater passes through the pagoda-shaped water distribution cap on the porous fixed disk. The water distribution cap is distributed with 0.5mm gaps to ensure that the influent water is evenly distributed into the fluidized bed tube. The influent water is adjusted so that the flow rate of area B is A2m / h, the flow rate of area A is A1m / h, and the flow rate of area C is A3m / h, which can ensure that 60-80 mesh particles will not overflow. Step S200: NaOH is added to the fluidized bed via a dosing pump. The dosing pipe is independent of the fluidized bed and connected to the center of the porous fixed plate. A claw-shaped alkali solution dosing pipe is connected to the pipe. Holes with a diameter of 1 mm are provided on the three branch pipes for distributing the alkali solution, ensuring uniform contact between the alkali solution and the influent water. The pH value of the effluent water is controlled to be 10.5-10.

9. Step S300: Add 60-80 mesh garnet to a seed crystal feeding hopper, which is connected to a seed crystal mixing hopper via a conveyor belt; a water inlet pump pumps water into the seed crystal mixing hopper, and after the water and seed crystals are fully mixed, the water is pumped into the fluidized bed via a feeding pump to prevent seed crystal blockage; as the crystals grow larger as the crystals crystallize, a seed crystal discharge pipe is opened to discharge the coarse particles into a collection tank; Step S400: The softened wastewater mixed with Mg(OH)2 flocs rises to the coagulation area, the flocculant control valve is opened, and the flocculant is added to the front end of the pipeline mixer through the agent dosing pipe, mixed with water and enters the pipeline mixer; the mixed water is dispersed through the guide plate; the flocs in the sedimentation area fall into the sludge collection bucket; the clean water overflows to the outlet trough for collection, thereby completing the wastewater treatment.

4. A wastewater treatment method according to claim 3, characterized in that: For wastewater with a total hardness of 2000mg / LCaCO3 and a total alkalinity of 900mg / L, where the Mg content is 110mg / L, after steps S100 to S400, the total hardness and Ca content of the effluent are 2+ Mg 2+ The concentrations were 315.98 mg / L, 78.43 mg / L and 28.23 mg / L respectively, and the effluent turbidity was 2 NTU, and the moisture content of the discharged sludge was 85%; Alternatively, for wastewater with a total hardness of 4000 mg / LCaCO3 and a total alkalinity of 120 mg / L, Mg 2+ The content is 300mg / L. After step S100 to step S400, the total hardness and Ca 2+ Mg 2+ The concentrations were 394.97 mg / L, 94.11 mg / L and 37.64 mg / L respectively, the effluent turbidity was 3.6 NTU, and the moisture content of the discharged sludge was 85%.

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