A high-efficiency crystallization fluidized bed equipment

Abstract

This invention provides a high-efficiency crystallization fluidized bed device. By setting up baffles, the crystallization reaction section inside the device is divided into a fluidized reaction zone, a large crystal settling zone, and a small crystal settling zone. The fluidized reaction zone includes a circulating reaction zone and a fluidized rising zone. Multi-point water inlet is used, with wastewater inlet pipes installed in the circulating reaction zone, large crystal settling zone, and small crystal settling zone respectively. The wastewater inlet provides circulating kinetic energy to the crystals in the circulating reaction zone, causing them to rise with the wastewater to the fluidized rising zone. Subsequently, some crystals continue to rise to the sedimentation effluent section, while the larger and smaller crystals fall into the large crystal settling zone and the small crystal settling zone respectively. Under the action of the wastewater inlet, they crystallize and increase in volume, falling back to the circulating reaction zone to continue purifying the wastewater, forming a good fluidized state. Multi-point water inlet ensures a uniform distribution of pollutant concentration within the crystallization reaction zone, avoiding excessively high local pollutant concentrations.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more particularly to a high-efficiency crystallization fluidized bed device. Background Technology

[0002] Chemical precipitation is a method of removing pollutants from wastewater by adding appropriate reagents to react with the pollutants and form insoluble precipitates. Currently, chemical precipitation is widely used in common water treatment projects such as water softening (hardness removal), phosphate removal, heavy metal ion removal, and fluoride removal due to its maturity, stability, and ease of operation. However, after decades of application, chemical precipitation has also revealed the following drawbacks:

[0003] (1) Chemical precipitation process needs to be used in conjunction with coagulation precipitation process. The process route is longer and there are more equipment. The power consumption is larger and the maintenance cost is also higher.

[0004] (2) The utilization rate of the reagents added in the chemical precipitation process is not high, and a large proportion of the reagents need to be added in excess, which easily leads to waste;

[0005] (3) The combination of chemical precipitation process and coagulation sedimentation process requires a large tank volume to meet the high retention time, resulting in a large footprint.

[0006] (4) The sludge produced by chemical precipitation needs to be filtered. After filtration, the sludge still has a moisture content of about 60%, and the higher moisture content will increase the sludge disposal cost.

[0007] Theoretically, all pollutants that can be treated by chemical precipitation can also be removed by crystallization. Therefore, in recent years, numerous fluidized bed crystallization reactors have been used to remove chemically precipitable pollutants such as hardness, fluoride ions, phosphate ions, ammonium ions, and some metal ions. A fluidized bed crystallization reactor is a physicochemical technology that continuously and efficiently induces crystallization by controlling the reaction supersaturation and the flow state of the liquid and solid phases. In the fluidized bed crystallization reactor, wastewater containing the target pollutant, reagents, and seed crystals move in the reactor according to a certain pattern. The target pollutant and reagents in the wastewater undergo a chemical reaction on the surface of the seed crystals, causing the seed crystals to grow larger and simultaneously achieving the effect of pollutant removal.

[0008] The fluidized bed crystallization process has the following advantages over chemical precipitation:

[0009] (1) The stay time is short (5-30 minutes), so the area occupied is small and the investment cost is low;

[0010] (2) The number of equipment is small, and operation and maintenance are simple;

[0011] (3) The power consumption and dosage are relatively low, resulting in lower operating costs;

[0012] (4) After the pollutants crystallize and precipitate, normal draining can reduce the moisture content to less than 15%, greatly reducing the volume of solid waste.

[0013] However, the current fluidized bed crystallization process also faces the following problems:

[0014] (1) The existing water distribution and chemical dosing structure of the crystallization fluidized bed is complex and easily damaged, requiring maintenance and replacement every 1-2 years.

[0015] (2) The upward flow velocity of existing crystallization fluidized beds is generally controlled between 50 m / h and 150 m / h, which limits the influent flow rate per unit cross-sectional area of ​​the reactor. When the influent flow rate is too large, the upward flow velocity exceeds 150 m / h, which will cause small crystals to be washed out.

[0016] (3) Existing crystallization fluidized beds generally use bottom water inlet and chemical dosing. The pollutant concentration is highest at the bottom of the crystallization fluidized bed and decreases sharply with increasing height. The removal of pollutants can be basically completed at a height of 1-3m. However, in order to form a better flow pattern, the height-to-diameter ratio of existing crystallization fluidized bed reactors is usually greater than 3.3 and the height is generally higher than 5.0m. Therefore, there is a large waste of internal space in the fluidized bed.

[0017] (4) The height of existing crystallization fluidized beds is generally between 5m and 30m. A larger fluidized bed height requires higher foundation bearing capacity and installation space, and also generates greater energy consumption for water intake.

[0018] (5) Bottom water intake and chemical addition result in the highest concentration of pollutants and the highest supersaturation at the bottom, which easily leads to primary nucleation and turbidity of the effluent. This disadvantage is particularly obvious when the concentration of pollutants in the influent is high.

[0019] (6) When the concentration of pollutants at the bottom is the highest, the crystallization load at the bottom is the largest, which easily leads to loose crystals at the bottom that are easy to disintegrate. This disadvantage is particularly obvious when the concentration of pollutants in the influent is high.

[0020] (7) When the pollutant concentration is highest at the bottom, the crystallization rate of the crystals at the bottom is the highest. At the same time, due to the quality of the crystals, the largest particles also remain at the bottom of the fluidized bed. This results in the largest crystal having the highest crystallization rate, making the size difference between the bottom and top crystals increasingly larger. As a result, the rising flow rate of the crystallization fluidized bed is difficult to meet the technical requirements of both the suspension and fluidization of large particles at the bottom and the prevention of small particles at the top from being washed away.

[0021] (8) Due to the uneven distribution of water in the existing crystallization fluidized bed, there are local areas with excessively fast upward flow velocity and insufficient upward flow velocity. Excessive upward flow velocity will cause the crystals to flow upward quickly, while insufficient upward flow velocity will cause the crystals to be unable to be lifted by the water flow and accumulate and settle. The sedimentation zone with higher crystal density will exist disorderly in any part of the reactor. The crystals in the sedimentation zone cannot participate in the reaction in time, reducing the efficiency of tank capacity utilization.

[0022] Patent CN116177762A discloses an internally pressurized self-circulating heterogeneous crystallization fluidized bed water treatment device. This device has a typical structure of existing fluidized beds, with the interior divided from bottom to top into an inlet zone, a reagent mixing zone, a reaction reflux zone, and a sedimentation separation zone. The inlet zone is equipped with a seed discharge port and a reagent inlet. This crystallization fluidized bed has a complex water distribution and dosing structure and does not partition the internal areas. It also has all the disadvantages of bottom inlet and dosing. It has poor volume utilization when treating high and low concentration wastewater, and the effluent is prone to turbidity when treating high concentration wastewater. The crystal structure is loose and easily disintegrates, and the space utilization efficiency can be improved.

[0023] Patent CN110395824A discloses a device and method for deep phosphorus removal and recovery of secondary effluent from wastewater treatment plants. It utilizes an upward flow of water in a fluidized bed to fluidize a large number of fine HAP seed crystals, forming an induced crystallization zone. Water is fed in from the bottom, and chemicals are added. Mixing and crystallization occur in the induced crystallization zone, thereby removing phosphorus. However, this fluidized bed crystallization system has a complex water distribution and chemical addition structure and lacks internal zoning. It also suffers from all the disadvantages of bottom-feed and bottom-addressed systems, resulting in poor space utilization when treating low-concentration phosphorus-containing wastewater.

[0024] In summary, while current fluidized bed crystallization processes have made significant progress compared to chemical precipitation in terms of removal efficiency, investment cost, land area, and operating cost, problems such as crystal breakage and turbid effluent still exist. Furthermore, there is still room for improvement in enhancing crystallization efficiency and space utilization. Therefore, it is necessary to develop a high-efficiency fluidized bed crystallization system that offers high space utilization, high crystallization efficiency, and stable effluent quality. Summary of the Invention

[0025] To address the problems of low crystallization efficiency, easy crystal disintegration, turbid effluent when treating high-concentration wastewater, and poor space utilization in existing fluidized bed crystallization technologies, this invention aims to provide a high-efficiency fluidized bed crystallization device. Internally, it is divided into a crystallization reaction section and a sedimentation effluent section from bottom to top. A partition further divides the crystallization reaction section into a fluidized reaction zone, a large crystal settling zone, and a small crystal settling zone. The fluidized reaction zone includes a circulating reaction zone and a fluidized rising zone. Furthermore, this application employs multi-point water inlet, with wastewater inlet pipes installed in the circulating reaction zone, the large crystal settling zone, and the small crystal settling zone, ensuring uniform pollutant concentration within the crystallization reaction section. The uniform distribution of wastewater in the circulating reaction zone provides kinetic energy to the crystals, causing them to rise with the wastewater to the fluidized rising zone. Subsequently, some crystals continue to rise to the sedimentation effluent section, while larger and smaller crystals fall into the large crystal settling zone and small crystal settling zone, respectively. Simultaneously, under the influence of the wastewater inflow, they rapidly crystallize and increase in volume, falling back to the circulating reaction zone to continue purifying the wastewater. The rising and falling processes of the wastewater and crystals do not interfere with each other, ensuring a good fluidization state inside the high-efficiency crystallization fluidized bed equipment. Multiple water inflow points prevent excessively high local pollutant concentrations and ensure stable crystallization rates in each zone.

[0026] To achieve the above objectives, the present invention provides the following technical solution:

[0027] A high-efficiency crystallization fluidized bed device includes: a reactor body and a base. The reactor body has a crystallization reaction section and a sedimentation effluent section arranged sequentially from bottom to top inside. The crystallization reaction section is equipped with multiple baffles, and the space within the crystallization reaction section is radially divided by the baffles into a fluidized reaction zone, a large crystal settling zone, and a small crystal settling zone. The fluidized reaction zone includes a circulating reaction zone and a fluidized rising zone, with the cross-sectional area of ​​the fluidized rising zone being less than or equal to the cross-sectional area of ​​the circulating reaction zone. The circulating reaction zone is equipped with a first wastewater inlet pipe and a return water inlet dosing pipe. The bottoms of the large crystal settling zone and the small crystal settling zone are both connected to the circulating reaction zone. The sedimentation effluent section is equipped with a purified water effluent pipe and a return water effluent pipe.

[0028] In some embodiments, both the large crystal precipitation zone and the small crystal precipitation zone are provided with a second sewage inlet pipe, the inlet flow velocity of the second sewage inlet pipe is greater than 0.2 m / s; the outlet of the second sewage inlet pipe is inclined downwards, and the angle with the horizontal direction is 45°–90°.

[0029] In some embodiments, the cross-sectional area of ​​the circulating reaction zone accounts for 50%-95% of the cross-sectional area of ​​the crystallization reaction section; the cross-sectional area of ​​the fluidization rising zone accounts for 50%-90% of the cross-sectional area of ​​the crystallization reaction section.

[0030] In some embodiments, the cross-sectional area of ​​the circulating reaction zone accounts for 80%-90% of the cross-sectional area of ​​the crystallization reaction section; and / or, the cross-sectional area of ​​the fluidization rising zone accounts for 70%-80% of the cross-sectional area of ​​the crystallization reaction section.

[0031] In some embodiments, the distance between the inlet of the small crystal settling zone and the sedimentation outlet section is less than the distance between the inlet of the large crystal settling zone and the sedimentation outlet section; the distance between the inlet of the small crystal settling zone and the inlet of the large crystal settling zone is greater than 0.1m.

[0032] In some embodiments, preferably, the distance between the inlet of the small crystal settling zone and the inlet of the large crystal settling zone is 0.4-2.5m.

[0033] In some embodiments, the inlet flow velocity of the first sewage inlet pipe, the return water inlet dosing pipe, and the second sewage inlet pipe is 5m / s-10m / s; and / or, the angle between the inlet of the second sewage inlet pipe and the horizontal direction is 75°-90°.

[0034] In some embodiments, the angle between the wastewater inlet pipe and the horizontal direction and the angle between the return water dosing pipe and the horizontal direction are 0°–90°; and / or, the cross-sectional shape of the circulating reaction zone, the fluidized rising zone, the large crystal settling zone and the small crystal settling zone is one of the following geometric shapes: rectangular, circular, or irregular.

[0035] In some embodiments, the height of the high-efficiency crystallization fluidized bed equipment is 2-8m.

[0036] In some embodiments, the circulating reaction zone is further provided with a crystal discharge port for discharging crystals; and / or, the sedimentation effluent section includes a crystal sedimentation zone and an effluent zone connected in sequence, the crystal sedimentation zone being used to separate purified water and crystals; the effluent zone is provided with a purified water effluent weir and a return water effluent weir, the purified water effluent weir being connected to the purified water effluent pipe, and the return water effluent weir being connected to the return water effluent pipe.

[0037] Compared with the prior art, the high-efficiency crystallization fluidized bed equipment provided by the present invention has the following beneficial effects:

[0038] 1. The high-efficiency crystallization fluidized bed equipment provided by the present invention is divided into a fluidization rising zone, a circulating reaction zone, a large crystal settling zone and a small crystal settling zone by a partition. The rising and falling processes of wastewater and crystals do not interfere with each other, which is conducive to forming an excellent fluidization state.

[0039] 2. The present invention has sewage inlet pipes in the circulating reaction zone, the large crystal precipitation zone and the small crystal precipitation zone respectively, and adopts multi-point water inlet to make the pollutant concentration in the crystallization reaction section uniformly distributed, so as to avoid the problem of excessive local supersaturation.

[0040] 3. The second wastewater inlet pipe set in the large crystal sedimentation zone and the small crystal sedimentation zone of this invention allows the falling crystals to crystallize rapidly and increase in volume in the high supersaturation zone. This avoids the widening of the crystal size difference between the bottom and top of the high-efficiency crystallization fluidized bed equipment, which would make it difficult to maintain the upward flow velocity. This ensures that the small particles of the required particle size are not washed away, while also ensuring that the large crystal particles at the bottom remain fluidized and do not settle.

[0041] 4. The multi-point water inlet provided by this invention can avoid the problem of excessively high pollutant concentration at the bottom of the high-efficiency crystallization fluidized bed equipment, which leads to an increase in the crystallization load of the bottom crystals and prevents the crystals from becoming loose and disintegrating.

[0042] 5. The high-efficiency crystallization fluidized bed equipment provided by the present invention has a height of less than 8m, which completes the crystallization reaction of pollutants within the most efficient height range, reducing the waste of space and height, and also reducing the requirements for foundation bearing capacity and installation space.

[0043] 6. The high-efficiency crystallization fluidized bed equipment provided in this application has a simple water distribution structure that is not easily damaged and requires no maintenance or replacement. Attached Figure Description

[0044] The preferred embodiments will now be described in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of the present invention.

[0045] Figure 1 This is a schematic diagram of the structure of the high-efficiency crystallization fluidized bed equipment provided by the present invention;

[0046] Figure 2 A cross-sectional view of the crystallization reaction section provided by the present invention;

[0047] Figure 3 A cross-sectional view of the crystallization reaction section in another embodiment of the present invention is provided;

[0048] Figure 4 A cross-sectional view of the crystallization reaction section in another embodiment of the present invention is provided.

[0049] Explanation of icon numbers:

[0050] 1—Reactor body; 2—Base; 3—Circulating reaction zone; 4—Fluidized rising zone; 5—Large crystal settling zone; 6—Small crystal settling zone; 8—First wastewater inlet pipe; 9—Recirculating water inlet dosing pipe; 10—Second wastewater inlet pipe; 11—Crystal settling zone; 12—Effluent zone; 13—Purified water effluent pipe; 14—Purified water effluent weir; 15—Recirculating water effluent pipe; 16—Recirculating water effluent weir; 17—Crystal discharge port. Detailed Implementation

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0052] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0053] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0054] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0056] This invention provides a high-efficiency crystallization fluidized bed device, such as... Figure 1 As shown, it includes a reactor body 1 and a base 2. The reactor body 1 is mounted on the base 2 and is fixedly connected to the base 2.

[0057] The reactor body 1 is arranged from bottom to top as a crystallization reaction section and a sedimentation effluent section.

[0058] The crystallization reaction section is equipped with multiple baffles 7. The space within the crystallization reaction section 7 is divided radially into a fluidized reaction zone, a large crystal settling zone 5, and a small crystal settling zone 6 by the baffles 7.

[0059] Furthermore, the fluidized reaction zone includes, from bottom to top, a circulating reaction zone 3 and a fluidized rising zone 4, with the cross-sectional area of ​​the fluidized rising zone 4 being less than or equal to the cross-sectional area of ​​the circulating reaction zone 3.

[0060] The bottom of both the large crystal settling zone 5 and the small crystal settling zone 6 are connected to the circulating reaction zone 3.

[0061] The circulating reaction zone 3 is equipped with a first sewage inlet pipe 8 and a return water inlet dosing pipe 9, and the sedimentation outlet section is equipped with a purified water outlet pipe 13 and a return water outlet pipe 15.

[0062] Within the crystallization reaction section, Figure 1 The dashed arrows indicate the flow direction of the crystals, while the solid arrows indicate the flow direction of the water. Wastewater to be treated, recycled water, or recycled water mixed with chemicals is introduced into the circulating reaction zone 3 to provide the crystals with the kinetic energy for circulation. The crystals move upwards with the water and enter the fluidized rising zone 4. The baffle 7 separates the areas with faster upward flow velocity (circulating reaction zone 3 and fluidized rising zone 4) from the descending areas (large crystal settling zone 5 and small crystal settling zone 6), ensuring that the rising and descending areas of wastewater / crystals do not interfere with each other. Some crystals continue to rise with the water to the sedimentation outlet section, while other crystals move laterally under the action of circulating kinetic energy. Due to the different crystal masses, larger crystals flow into the large crystal settling zone 5, while smaller crystals flow into the small crystal settling zone 6. Since the bottom of both the large crystal settling zone 5 and the small crystal settling zone 6 are connected to the circulating reaction zone 3, when sewage or return water is introduced into the circulating reaction zone 3 again, the crystals settled in the large crystal settling zone 5 and the small crystal settling zone 6 rise again with the water under the action of circulating kinetic energy.

[0063] In some embodiments, the angle between the sewage inlet pipe 8 and the horizontal direction and the angle between the return water inlet dosing pipe 9 and the horizontal direction are 0°–90°, that is, the angle between the flow direction of the water discharged from the sewage inlet pipe 8 and the return water inlet dosing pipe 9 and the horizontal direction is 0°–90°. Preferably, the angle is 30°–60°. The inlet flow velocity of the first sewage inlet pipe 8 and the return water inlet dosing pipe 9 is controlled to be greater than 0.2 m / s, preferably 5 m / s–10 m / s.

[0064] The special structure and inlet flow rate of the aforementioned sewage inlet pipe 8 and return water dosing pipe 9 can provide sufficient circulating kinetic energy for the crystals in the circulating reaction zone 3.

[0065] It should be noted that the kinetic energy of the circulation within the aforementioned circulation reaction zone 3 is generally provided by the kinetic energy of the sewage (or return water) discharged from the first sewage inlet pipe 8 (or return water dosing pipe 9). If the kinetic energy of the sewage (or return water) is insufficient to provide the kinetic energy of the circulation, any method with a propulsion effect, such as built-in propulsion and stirring, can be adopted.

[0066] In some embodiments, the cross-sectional area of ​​the circulating reaction zone 3 accounts for 50%-95% of the cross-sectional area of ​​the crystallization reaction section.

[0067] Preferably, the cross-sectional area of ​​the circulating reaction zone 3 accounts for 80%-90% of the cross-sectional area of ​​the crystallization reaction section.

[0068] The cross-sectional area of ​​fluidization rising zone 4 accounts for 50%–90% of the cross-sectional area of ​​the crystallization reaction zone.

[0069] Preferably, the cross-sectional area of ​​the fluidization rising zone 4 accounts for 70%-80% of the cross-sectional area of ​​the crystallization reaction zone.

[0070] In this embodiment, the cross-sectional area of ​​the circulating reaction zone 3 and the cross-sectional area of ​​the fluidization rising zone 4 are defined, thereby defining the cross-sectional area of ​​the large crystal precipitation zone 5 and the cross-sectional area of ​​the small crystal precipitation zone 6. The water flow rate in each zone is controlled by changing the cross-sectional area of ​​each zone.

[0071] Considering that in actual operation, if the concentration of pollutants in the influent is high, the pollutant concentration distribution in different sections of the fluidized bed will be uneven, with the highest pollutant concentration at the bottom. This can easily increase the local crystallization load at the bottom, causing the crystals to loosen and disintegrate, and the crystallization rate at the bottom differs too much from that at the top. Therefore, the inventors proposed a multi-point influent design scheme:

[0072] A second sewage inlet pipe 10 is installed in both the large crystal sedimentation zone 5 and the small crystal sedimentation zone 6.

[0073] Taking the small crystal sedimentation zone 6 as an example, the inlet of the second sewage inlet pipe 10 extends into the small crystal sedimentation zone 6 through the outer wall of the reactor body 1 and is inclined downwards. The angle between the inlet and the horizontal direction is 45°-90°. Preferably, the angle between the inlet and the horizontal direction is 75°-90°.

[0074] The inflow velocity of the second sewage inlet pipe 10 is controlled to be greater than 0.2 m / s, preferably 5 m / s to 10 m / s.

[0075] This invention first separates the circulating reaction zone 3, the large crystal sedimentation zone 5, and the small crystal sedimentation zone 6 by using a partition. Then, wastewater inlet pipes are installed in each zone. The multi-point water inlet design balances the pollutant concentration in the crystallization reaction zone and controls the supersaturation distribution in the crystallization reaction zone. This avoids the highest point of crystallization supersaturation remaining at the bottom of the high-efficiency crystallization fluidized bed equipment, reduces the probability and number of primary nucleation in the crystallization reaction zone, avoids turbid effluent, and also improves the efficiency of pool volume utilization.

[0076] Assuming the influent flow rate of this high-efficiency crystallization fluidized bed equipment is set to 4X, 2X of 4X can be allocated to the first wastewater inlet pipe 8, and the remaining 2X can be allocated to the second wastewater inlet pipes 10 in the large crystal sedimentation zone 5 and the small crystal sedimentation zone 6, respectively. The wastewater is then fed into the high-efficiency crystallization fluidized bed equipment through the two second wastewater inlet pipes 10, reducing the pollutant concentration at the bottom of the equipment and evenly distributing the pollutant-containing influent within the crystallization reaction section. Similarly, after the high-efficiency crystallization fluidized bed equipment has been running for a period of time, a portion of the return water can be allocated to the second wastewater inlet pipe 10 as needed, and fed into the crystallization reaction section through the second wastewater inlet pipe 10. This is especially important in the initial stage of wastewater purification by the high-efficiency crystallization fluidized bed equipment, when the pollutant concentration in both the influent and return water is relatively high.

[0077] Multiple water inlets maintain a certain range of pollutant concentrations within the circulating reaction zone 3, large crystal sedimentation zone 5, and small crystal sedimentation zone 6, preventing complete overlap with the circulating reaction zone 3 where large-diameter crystals are more concentrated. This allows small-diameter crystals in the upper and middle parts of the crystallization reaction section (falling back to the large crystal sedimentation zone 5 and small crystal sedimentation zone 6) to rapidly crystallize and increase their volume in the highly supersaturated pollutant area. This avoids the crystal size difference between the bottom and top of the crystallization reaction section from widening, which would make it difficult to control the upward flow velocity. It ensures that small-diameter crystal particles are not washed away, while also ensuring that large-diameter crystals at the bottom remain fluidized and do not settle.

[0078] Meanwhile, multiple water inlets also bring excellent water distribution effect: the setting of the second sewage inlet pipe 10 can provide the crystals settling and falling in the large crystal sedimentation zone 5 and the small crystal sedimentation zone 6 with the kinetic energy to participate in the circulation. Combined with the kinetic energy provided by the sewage (or return water) discharged from the first sewage inlet pipe 8 (or return water dosing pipe 9), it is conducive to the full diffusion of the reaction substrate in the crystallization reaction section, avoiding the excessive saturation concentration at the bottom of the crystallization reaction section, which would cause the crystal crystallization load to be too high, and ultimately avoiding the problem of loose crystals at the bottom of the high-efficiency crystallization fluidized bed equipment that are easy to disintegrate.

[0079] The beneficial effects of multi-point water inlet are particularly evident when the concentration of pollutants in the influent is high.

[0080] It should be noted that, in order to ensure the stability of the purified water effluent quality, no return water inlet and sewage inlet pipes are installed in the sewage upward flow area between the middle height of the fluidization rising zone 4 and the effluent weir 14, so as to ensure that the sewage has sufficient mass transfer and reaction space in the sulfidation reaction bed.

[0081] The multi-point water distribution structure (first sewage inlet pipe, return water inlet dosing pipe and second sewage inlet pipe) provided by this invention is not easily damaged and does not require frequent maintenance and replacement.

[0082] In some embodiments, the above-mentioned sedimentation and effluent section includes a crystal sedimentation zone 11 and an effluent zone 12 connected in sequence. The crystal sedimentation zone 11 is used to separate purified water and crystals. The effluent zone 12 is provided with a purified water effluent weir 14 and a return water effluent weir 16. The purified water effluent weir 14 is connected to the purified water effluent pipe 13, and the return water effluent weir 16 is connected to the return water effluent pipe 15.

[0083] Solid-liquid separation is achieved in the crystal precipitation zone 11. The crystals that rise with the water descend here and fall back into the circulating settling zone 3. The purified water enters the effluent zone 12. Part of it flows into the purified water effluent weir 14 and is then discharged through the purified water effluent pipe 15. The other part of the purified water flows into the return water effluent weir 16 and is then discharged through the return water effluent pipe 15. It can then enter the circulating reaction zone 3 for circulating purification through the return water inlet dosing pipe 9.

[0084] In some embodiments, the circulating reaction zone 3 is also provided with a crystal discharge port 17 for discharging crystals. After the high-efficiency crystallization fluidized bed equipment has been running for a period of time, the internal crystals can be discharged through the crystal discharge port 17 and the seed crystals can be reintroduced.

[0085] In some implementations, the inlet of the small crystal settling zone 6 is higher than the inlet of the large crystal settling zone 5.

[0086] That is, Figure 1 As shown, the distance between the inlet of the small crystal settling zone 6 and the sedimentation outlet section is smaller than the distance between the inlet of the large crystal settling zone 5 and the sedimentation outlet section.

[0087] The distance between the entrance to the small crystal settling zone 6 and the entrance to the large crystal settling zone 5 is greater than 0.1m.

[0088] Preferably, the distance between the inlet of the small crystal settling zone 6 and the inlet of the large crystal settling zone 5 is 0.4-2.5m.

[0089] In some embodiments, the cross-sectional shape of the circulating reaction zone 3, the fluidization rising zone 4, the large crystal settling zone 5, and the small crystal settling zone 6 is one of a rectangular, circular, or irregular geometric shape, and the shape and area of ​​each zone may be inconsistent.

[0090] Figure 2-4Several implementations of cross-sectional views of the crystallization reaction section are shown. Figure 2 The diagram shows an implementation where the cross-sections of the circulating reaction zone 3, the fluidization rising zone 4, the large crystal settling zone 5, and the small crystal settling zone 6 are all irregular geometric shapes.

[0091] Figure 3 The embodiment shown is when the cross-sections of the circulating reaction zone 3, the fluidization rising zone 4, the large crystal settling zone 5, and the small crystal settling zone 6 are all circular.

[0092] Figure 4 The embodiment shown is when the cross-sections of the circulating reaction zone 3, the fluidization rising zone 4, the large crystal settling zone 5, and the small crystal settling zone 6 are all rectangular.

[0093] In some embodiments, the height of the high-efficiency crystallization fluidized bed equipment provided by the present invention is 1-12m, and more preferably, the height of the high-efficiency crystallization fluidized bed equipment is 2-8m, which reduces the requirements for foundation bearing capacity and installation space.

[0094] High-efficiency crystallization fluidized bed equipment can be operated independently or multiple high-efficiency crystallization fluidized bed equipment can be operated in parallel.

[0095] The present invention provides an efficient crystallization fluidized bed equipment with an influent flow velocity between 100 m / h and 1000 m / h, a wider influent flow range, and a greater water volume that can be processed per unit cross-sectional area.

[0096] The tank material (reactor body) of the high-efficiency crystallization fluidized bed equipment can be metal or non-metal, such as stainless steel, carbon steel, PP material, etc., but not limited to the materials listed above.

[0097] The feed pump and reflux pump components in high-efficiency crystallization fluidized bed equipment have small heads, which can save energy.

[0098] In summary, the operation process of the high-efficiency crystallization fluidized bed equipment provided by this invention is briefly described as follows:

[0099] A portion of the wastewater is fed into the circulating reaction zone 3 at a certain flow rate through the first wastewater inlet pipe 8, bringing in kinetic energy. The crystals are fully mixed with the wastewater through the circulation, undergoing a preliminary crystallization reaction. Subsequently, the wastewater moves upward into the fluidized rising zone 4 for further crystallization. A portion of the crystals enters the crystal settling zone 11, while another portion moves laterally into the large crystal settling zone 5 and the small crystal settling zone 6. At the same time, another portion of the wastewater enters the large crystal settling zone 5 and the small crystal settling zone 6 through the second wastewater inlet pipe 10, respectively, and undergoes a crystallization reaction with the falling large and small crystals. The crystals in the large crystal settling zone 5 and the small crystal settling zone 6 re-enter the circulating reaction zone 3 with the water, repeating the above crystallization process.

[0100] The crystals separated from the solid in the crystal settling zone 11 fall into the fluidized rising zone 4, the large crystal settling zone 5, or the small crystal settling zone 6. Part of the purified water flows into the return water outlet weir 16 and enters the high-efficiency crystallization fluidized bed equipment through the return water outlet pipe 15 and the return water inlet dosing pipe 9. The other part of the purified water flows into the purified water outlet pipe 13 through the purified water outlet weir 14 and is discharged from the high-efficiency crystallization fluidized bed equipment.

[0101] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-efficiency crystallization fluidized bed device, characterized in that, include: Reactor body and base, The reactor body is arranged from bottom to top as a crystallization reaction section and a sedimentation effluent section; The crystallization reaction section is equipped with multiple baffles, and the space within the crystallization reaction section is divided radially into a fluidized reaction zone, a large crystal settling zone, and a small crystal settling zone by the baffles. The fluidized reaction zone comprises, from bottom to top, a circulating reaction zone and a fluidized rising zone, wherein the cross-sectional area of ​​the fluidized rising zone is less than or equal to the cross-sectional area of ​​the circulating reaction zone; The circulating reaction zone is equipped with a first sewage inlet pipe and a return water inlet dosing pipe, and both the large crystal sedimentation zone and the small crystal sedimentation zone are equipped with second sewage inlet pipes to form multiple water inlets within the crystallization reaction section; The bottom of the large crystal settling zone and the bottom of the small crystal settling zone are both connected to the circulating reaction zone; The sedimentation and effluent section includes a crystal sedimentation zone and an effluent zone. The effluent zone is equipped with a purified water effluent weir and a return water effluent weir, which are respectively connected to the purified water effluent pipe and the return water effluent pipe. The inlet of the small crystal settling zone is higher than the inlet of the large crystal settling zone so that the distance between the inlet of the small crystal settling zone and the sedimentation effluent section is smaller than the distance between the inlet of the large crystal settling zone and the sedimentation effluent section.

2. The high-efficiency crystallization fluidized bed equipment according to claim 1, characterized in that, The inflow velocity of the second sewage inlet pipe is greater than 0.2 m / s; The inlet of the second sewage inlet pipe is inclined downwards, and the angle between it and the horizontal direction is 45°–90°.

3. The high-efficiency crystallization fluidized bed equipment according to claim 1, characterized in that, The cross-sectional area of ​​the circulating reaction zone accounts for 50%–95% of the cross-sectional area of ​​the crystallization reaction section; The cross-sectional area of ​​the fluidization rising zone accounts for 50%–90% of the cross-sectional area of ​​the crystallization reaction section.

4. The high-efficiency crystallization fluidized bed equipment according to claim 3, characterized in that, The cross-sectional area of ​​the circulating reaction zone accounts for 80%-90% of the cross-sectional area of ​​the crystallization reaction section; and / or, The cross-sectional area of ​​the fluidization rising zone accounts for 70%-80% of the cross-sectional area of ​​the crystallization reaction section.

5. The high-efficiency crystallization fluidized bed equipment according to claim 1, characterized in that, The distance between the entrance to the small crystal settling zone and the entrance to the large crystal settling zone is greater than 0.1m.

6. The high-efficiency crystallization fluidized bed equipment according to claim 5, characterized in that, The distance between the entrance to the small crystal settling zone and the entrance to the large crystal settling zone is 0.4–1.5 m.

7. The high-efficiency crystallization fluidized bed equipment according to claim 2, characterized in that, The inlet flow velocities of the first sewage inlet pipe, the return water inlet dosing pipe, and the second sewage inlet pipe are all 5 m / s to 10 m / s; and / or, The angle between the inlet of the second sewage inlet pipe and the horizontal direction is 75°–90°.

8. The high-efficiency crystallization fluidized bed equipment according to claim 1, characterized in that, The angle between the wastewater inlet pipe and the horizontal direction and the angle between the return water inlet dosing pipe and the horizontal direction are 0°–90°; and / or, The cross-sectional shape of the circulating reaction zone, the fluidization rising zone, the large crystal settling zone, and the small crystal settling zone is one of the following geometric shapes: rectangular, circular, or irregular.

9. The high-efficiency crystallization fluidized bed equipment according to claim 1, characterized in that, The height of the high-efficiency crystallization fluidized bed equipment is 2-8m.

10. The high-efficiency crystallization fluidized bed equipment according to claim 1, characterized in that, The circulating reaction zone is also provided with a crystal discharge port for discharging crystals.

Images