A seawater desalination impurity pretreatment system and process

Abstract

The present invention relates to the technical field of seawater desalination impurity treatment, and specifically discloses a seawater desalination impurity pretreatment system and process, wherein the pretreatment process includes coarse filtration, flocculation sedimentation, filter filtration and ultrafiltration, and the flocculation sedimentation steps are as follows: S100, detecting the temperature of the seawater after coarse filtration. When it is lower than a set temperature range that is conducive to the flocculation reaction, the waste heat recovered from evaporating the seawater is used to heat the seawater after coarse filtration; S200, transporting the heated seawater to a mixing tank and detecting its temperature, and adding a flocculant according to the dosage corresponding to the temperature; S300, transporting the seawater mixed with the flocculant to a flocculation reaction tank; S400, transporting the seawater after the flocculation reaction to a flocculation sedimentation tank, measuring concentration data at different depths in the flocculation sedimentation tank, and correcting the front-end reaction control parameters according to each measurement data. The present invention has targeted control of temperature effects and establishes a dynamic feedback adjustment mechanism based on the flocculation sedimentation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of seawater desalination impurity treatment, in particular to a seawater desalination impurity pretreatment system and process. Background Art

[0002] In the seawater desalination process, impurity pretreatment is a very important link, and its treatment effect directly affects the efficiency, energy consumption and quality of the subsequent desalination process.

[0003] Currently, common desalination impurity pretreatment processes typically include coarse filtration, flocculation and sedimentation, multi-media filtration, safety filter filtration, and ultrafiltration. Flocculation and sedimentation are the most challenging and critical steps influencing overall treatment effectiveness. Due to significant variations in temperature, turbidity, organic matter content, and salinity across different sea areas and at different times, the relatively fixed flocculant dosage, agitation intensity, and water flow rate used in traditional processes can easily lead to unstable flocculation results.

[0004] If flocculation and sedimentation are inadequate, large amounts of suspended solids, colloids, and other impurities can enter the multi-media filter, accelerating clogging of the filter media and requiring frequent backwashing, increasing energy consumption and shortening filter life. This can also easily lead to a significant amount of suspended solids, colloids, and other impurities penetrating the multi-media filter's interceptor system and entering subsequent processing steps, placing a significant strain on the safety filter and ultrafiltration membrane. These impurities can quickly clog the safety filter element, dramatically increasing its filtration resistance, shortening replacement cycles, and increasing consumable costs. Even after being intercepted by the safety filter, some fine impurities can still enter the ultrafiltration process, accelerating membrane surface contamination and causing rapid flux degradation. This can lead to frequent air-water backwashing and even chemical cleaning, significantly reducing the efficiency of the ultrafiltration system.

[0005] If the ultrafiltration membrane is damaged due to excessive contamination, the unretained impurities will directly enter the heating and evaporation process, forming stubborn scale on the surface of the evaporation equipment's heating tubes, seriously affecting heat transfer efficiency and causing a surge in energy consumption. Furthermore, the corrosive components in these impurities will accelerate the corrosion process of the equipment, shortening the service life of the evaporation equipment, significantly increasing the overall operating cost of seawater desalination, and hindering the efficient and stable application of seawater desalination technology.

[0006] Among existing patent technologies, the invention patent with application number CN202411987506.6 discloses an automatic dosing adjustment device and method for a flocculation sedimentation tank in a seawater desalination system. The automatic dosing adjustment device for a flocculation sedimentation tank in a seawater desalination system includes a reagent concentration module, a flocculation tank inlet seawater flow rate setting module, a metering pump on-site range input module, a flocculation sedimentation tank selection module, a dosing metering pump selection module, a dosing calculation module, a dosing module, and a seawater desalination pretreatment module. The dosing calculation module is connected to the reagent concentration module and the flocculation tank inlet seawater flow rate setting module. The seawater desalination pretreatment module is connected to the flocculation tank inlet seawater flow rate setting module, the flocculation sedimentation tank selection module, the dosing metering pump selection module, and the dosing calculation module. The dosing module is connected to the dosing calculation module and the metering pump on-site range input module.

[0007] The above-mentioned patented solution achieves automatic adjustment of dosing by setting up corresponding modules on the distributed control system, thereby solving the problems of high human error and complex operation caused by manual dosing by manually changing the frequency. At the same time, the stability of the flocculation reaction is improved to a certain extent through the automatic adjustment of the flocculant. However, this patented technology still has limitations. It only focuses on the automatic adjustment of the flocculant and lacks targeted treatment of the key influencing factor, seawater temperature. Seawater temperature directly affects the dissolution rate and activity of the flocculant. Low temperature environments can easily lead to delayed flocculation reaction and slow floc formation, which in severe cases can reduce the flocculation effect. At the same time, this patented solution lacks a means to detect the flocculation and sedimentation effects, and cannot dynamically correct the front-end reaction control parameters based on the test results. When the flocculation reaction encounters problems such as fine floc fragmentation and incomplete sedimentation, it is impossible to correct them in time by optimizing the front-end reaction control parameters. This will result in a large amount of impurities that are not fully flocculated entering the subsequent treatment unit. Summary of the Invention

[0008] The purpose of the present invention is to provide a seawater desalination impurity pretreatment system and process, aiming to improve the problem that the existing seawater desalination impurity pretreatment process lacks targeted regulation of temperature effects and has not established a dynamic feedback adjustment mechanism based on flocculation and sedimentation effects, which easily leads to excessive load on subsequent treatment units.

[0009] The present invention is achieved in that:

[0010] According to a first aspect of the present invention, the present invention provides a seawater desalination impurity pretreatment process, comprising coarse filtration, flocculation sedimentation, filter filtration and ultrafiltration, wherein the flocculation sedimentation has the following specific steps:

[0011] S100, detecting the temperature of the seawater after coarse filtration. When the seawater temperature is lower than a set temperature range conducive to flocculation reaction, using waste heat recovered from evaporating the seawater to heat the coarsely filtered seawater. When the waste heat energy is sufficient, the seawater temperature is stabilized in a temperature range conducive to flocculation reaction.

[0012] S200, transporting the heated seawater to a mixing tank, detecting the temperature of the heated seawater, adding a flocculant according to a dosage corresponding to the temperature, and mixing the flocculant with the seawater;

[0013] S300, transporting the seawater mixed with the flocculant to a flocculation reaction tank for flocculation reaction;

[0014] S400, transporting the seawater after the flocculation reaction to a flocculation sedimentation tank, measuring the concentration data at different depths of the flocculation sedimentation tank, and correcting the flocculant dosage, the flow rate of the seawater entering the flocculation sedimentation tank, the stirring intensity of the mixing tank, the residence time of the seawater in the flocculation reaction tank, and the stirring intensity in the flocculation reaction tank based on the measured data.

[0015] Furthermore, a rapid mixing zone and a slow flocculation zone are sequentially arranged in the flocculation reaction tank along the flow direction of seawater, and both the rapid mixing zone and the slow flocculation zone are provided with stirring devices. The stirring intensity in the flocculation reaction tank includes the stirring intensity of the rapid mixing zone and the stirring intensity of the slow flocculation zone.

[0016] Furthermore, in step S400, concentration sensors are set at different depths of the flocculation sedimentation tank, including an upper water concentration sensor, a middle water concentration sensor, and a lower water concentration sensor. The upper water concentration sensor is set at 0.5-1 meters below the water surface, and the middle water concentration sensor is set at a depth of 0.5-1 meters from the bottom of the tank. within the range of is the depth of the thickening tank, and The lower water concentration sensor is arranged within a range of 0.3-0.8 meters from the bottom of the pool.

[0017] Furthermore, the measurement data of the upper layer water concentration sensor, the middle layer water concentration sensor and the lower layer water concentration sensor are C1, C2 and C3 respectively, and the corresponding preset concentration thresholds are T1, T2 and T3 respectively, and T1<T2<T3;

[0018] If C1<T1 and C2<T2, no correction is performed;

[0019] If C3 ≥ T3, immediately open the mud discharge device at the bottom of the flocculation sedimentation tank;

[0020] If C1 < T1 and C2 ≥ T2, then reduce the stirring intensity of the slow flocculation zone, and simultaneously select to perform one or more of the following adjustment operations: increase the stirring intensity of the mixing tank, increase the stirring intensity of the fast mixing zone in the flocculation reaction tank, increase the dosage of the flocculant, reduce the flow rate of seawater entering the flocculation sedimentation tank, and extend the residence time of seawater in the flocculation reaction tank;

[0021] If C1 ≥ T1 and C2 < T2, then increase the stirring intensity of the mixing tank and the stirring intensity of the rapid mixing zone in the flocculation reaction tank, and simultaneously select to perform one or more of the following adjustment operations: increase the dosage of flocculant, reduce the flow rate of seawater entering the flocculation sedimentation tank, and extend the residence time of seawater in the flocculation reaction tank;

[0022] If C1 ≥ T1 and C2 ≥ T2, then:

[0023] When C3 < T3, increase the stirring intensity of the mixing tank, increase the stirring intensity of the fast mixing zone in the flocculation reaction tank, increase the dosage of flocculant, reduce the stirring intensity of the slow flocculation zone, and simultaneously select to perform one or more of the following adjustment operations: reduce the flow rate of seawater entering the flocculation sedimentation tank, and extend the residence time of seawater in the flocculation reaction tank;

[0024] When C3≥T3, increase the stirring intensity of the mixing tank, increase the stirring intensity of the fast mixing zone in the flocculation reaction tank, increase the dosage of flocculant, reduce the stirring intensity of the slow flocculation zone, reduce the flow rate of seawater entering the flocculation sedimentation tank, extend the residence time of seawater in the flocculation reaction tank, and immediately open the sludge discharge device at the bottom of the flocculation sedimentation tank and increase the sludge discharge speed.

[0025] Furthermore, based on different concentration data combinations, the specific quantitative correction methods for each process parameter are as follows:

[0026] If C1<T1 and C2≥T2:

[0027] When reducing the stirring intensity in the slow flocculation zone, the stirring speed is reduced by 10%-15%;

[0028] When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 10%-15%;

[0029] When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed is increased by 10%-15%; when increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5;

[0030] When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 80%-90% of the original flow rate;

[0031] When the residence time of seawater in the flocculation reaction tank is extended, the inlet flow rate is reduced by 10%-20%;

[0032] If C1 ≥ T1 and C2 < T2:

[0033] When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 15%-25%;

[0034] When increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5;

[0035] When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 80%-90% of the original flow rate;

[0036] When the residence time of seawater in the flocculation reaction tank is extended, the inlet flow rate is reduced by 10%-20%;

[0037] If C1≥T1, C2≥T2 and C3<T3:

[0038] When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 20%-30%;

[0039] When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed increases by 20%-25%;

[0040] When reducing the stirring intensity in the slow flocculation zone, the stirring speed is reduced by 15%-25%;

[0041] When increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: , where k is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5; among them, , ;

[0042] When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 70%-80% of the original flow rate;

[0043] When the residence time of seawater in the flocculation reaction tank is extended, the inlet flow rate is reduced by 15%-25%;

[0044] If C1 ≥ T1, C2 ≥ T2 and C3 ≥ T3:

[0045] When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 30%-35%;

[0046] When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed increases by 25%-30%;

[0047] When reducing the stirring intensity of the slow flocculation zone, the stirring speed is reduced by 15%-25%; when increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.1-0.2; when hour, Take 0.2-0.3; when hour, Take 0.3-0.4; when hour, Take 0.5-0.6; among them, , , ;

[0048] When reducing the stirring intensity in the slow flocculation zone, the stirring speed is reduced by 20%-30%;

[0049] When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 60%-70% of the original flow rate;

[0050] When the residence time of seawater in the flocculation reaction tank is extended, the inlet flow rate is reduced by 20%-30%;

[0051] When opening the mud discharge device at the bottom of the flocculation sedimentation tank, increase the speed of the mud discharge pump by 50% and increase the operating frequency of the scraper motor at the same time.

[0052] Furthermore, the temperature range conducive to the flocculation reaction is 27-32 degrees Celsius; the ultrafiltration step uses a hollow fiber ultrafiltration membrane with a membrane pore size of 0.01-0.1 μm and an operating pressure of 0.1-0.3 MPa. During the ultrafiltration process, air-water backwashing is performed every 30-60 minutes, and the backwashing time is 3-5 minutes; when the membrane flux drops to 70%-80% of the initial value, the chemical cleaning program is started, and a citric acid solution with a mass fraction of 2%-3% or a sodium hydroxide solution with a mass fraction of 0.5%-1% is used for circulating cleaning, and the cleaning time is 60-90 minutes.

[0053] According to the second aspect of the present invention, the present invention provides a seawater desalination impurity pretreatment system, comprising a coarse filtration module, a flocculation sedimentation module, a filter module, an ultrafiltration module, a control system module, and a pipeline and valve system module; the flocculation sedimentation module comprises a seawater temperature detection unit, a heating unit, a mixing tank unit, a flocculation reaction tank unit, and a flocculation sedimentation tank unit, the seawater temperature detection unit comprises an inlet water temperature detection sensor and an outlet water temperature detection sensor, the heating unit is used to heat the seawater discharged from the coarse filtration module, the inlet water temperature detection sensor is used to detect the temperature of the seawater discharged from the coarse filtration module, and the outlet water temperature detection sensor is used to detect the temperature of the seawater after heating by the heating unit; the mixing tank unit comprises a mixing tank and a flocculant addition system, ... A stirring device is provided in the mixing tank, and the flocculant addition system is used to add flocculant to the mixing tank; the flocculation reaction tank unit includes a rapid mixing zone and a slow flocculation zone arranged in sequence along the direction of coastal water flow, a guide plate is provided between the rapid mixing zone and the slow flocculation zone, and a stirring device is provided in both the rapid mixing zone and the slow flocculation zone; the flocculation sedimentation tank unit includes a flocculation sedimentation tank, and a plurality of concentration sensors are provided in the flocculation sedimentation tank, and each concentration sensor is respectively provided at a different depth in the flocculation sedimentation tank; the control system module is used to be electrically connected to the coarse filtration module, the flocculation sedimentation module, the filter module, the ultrafiltration module and the pipeline and valve system module, to collect data transmitted from each module in real time, and to perform corresponding regulation based on the preset algorithm and threshold judgment.

[0054] Furthermore, the concentration sensor in the flocculation sedimentation tank includes an upper water concentration sensor, a middle water concentration sensor and a lower water concentration sensor. The upper water concentration sensor is set at 0.5-1 meters below the water surface, and the middle water concentration sensor is set at a distance of 1 meter from the bottom of the tank. within the range of is the depth of the thickening tank, and The lower water concentration sensor is arranged within a range of 0.3-0.8 meters from the bottom of the pool.

[0055] Furthermore, the pipeline and valve system module is used to connect the coarse filtration module, the flocculation and sedimentation module, the filter module, and the ultrafiltration module to form a complete seawater transportation path; the pipeline and valve system module is provided with an electrically controlled regulating valve on the connecting pipeline between the coarse filtration module and the flocculation and sedimentation module, which is used to regulate the flow rate of seawater entering the flocculation and sedimentation module under the control of the control system module; and an electrically controlled regulating valve is provided on the pipeline between the flocculation reaction tank unit and the flocculation sedimentation tank unit, which is used to regulate the flow rate of seawater entering the flocculation sedimentation tank under the control of the control system module.

[0056] Furthermore, the filter module includes a multi-media filter and a security filter, the multi-media filter includes a tank body, a lifting assembly and a water pump, the tank body is provided with a sewage suction pipe and an ultrasonic generator, and the water suction end of the water pump is connected to the sewage suction pipe; the lifting assembly is installed on the tank body, and the output end of the lifting assembly is inserted into the tank body, the sewage suction pipe is plugged and connected to a directional suction pipe, and the directional suction pipe is connected to the output end of the lifting assembly, and the lifting assembly is used to drive the directional suction pipe to move up and down; a multi-media filter element is provided in the tank body, and there are multiple multi-media filter elements, and they are located in the tank body, and guide plates are provided at the top and bottom ends of the multi-media filter element and between two adjacent filter media, and guide holes are evenly opened on the guide plates, and the aperture size of the guide holes on each guide plate is different, and the aperture size of the guide holes of multiple guide plates gradually decreases from top to bottom.

[0057] Compared with existing technologies, the present invention offers the following advantages: The desalination impurity pretreatment process addresses the significant impact of seawater temperature on the flocculation reaction by utilizing the residual heat from evaporation to heat the coarsely filtered seawater. This stabilizes the temperature of the seawater entering the flocculation and sedimentation process within or closer to a temperature range favorable for the flocculation reaction. This effectively improves the hydrolysis efficiency and activity of the flocculant, thereby enhancing its effectiveness. Furthermore, the flocculant dosage is precisely matched to the real-time water temperature, avoiding waste or insufficient flocculant due to temperature fluctuations. Furthermore, by installing concentration sensors at different depths in the flocculation sedimentation tank, a stratified monitoring system for different depths of the flocculation sedimentation tank is established. A dynamic feedback adjustment mechanism based on the seawater concentration at different depths of the flocculation sedimentation tank is also established. When the detection data indicates that the flocculation and sedimentation effect deviates from expectations, key parameters such as the flocculant dosage, the flow rate of seawater entering the flocculation sedimentation tank, the stirring intensity in each reaction zone, and the seawater residence time are automatically optimized and corrected. This effectively ensures the stability and efficiency of the flocculation and sedimentation effect, provides water inlet conditions with stable water quality and low impurity content for subsequent treatment processes, and effectively reduces the load on subsequent treatment processes. Other advantages of the present invention are described in the subsequent specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a process flow chart of the seawater desalination impurity pretreatment process provided by the present invention;

[0059] Figure 2 This is the specific process of flocculation and sedimentation in the seawater desalination impurity pretreatment process provided by the present invention;

[0060] Figure 3 This is a module block diagram of the seawater desalination impurity pretreatment system provided by the present invention;

[0061] Figure 4 This is a schematic structural diagram of the multi-media filter provided by the present invention at an oblique top-down perspective;

[0062] Figure 5 This is a schematic structural diagram of the multi-media filter provided by the present invention when separated at an oblique upward viewing angle;

[0063] Figure 6 It is a structural diagram of the lower splicing part of the multi-media filter;

[0064] Figure 7 It is a structural diagram of the middle splicing part of the multi-media filter;

[0065] Figure 8 This is a block diagram of the structure inside the control box of the multi-media filter;

[0066] Figure 9 It is a structural diagram of the upper splicing part of the multi-media filter;

[0067] Figure 10 It is a structural diagram of the lifting assembly of the multi-media filter;

[0068] Figure 11 It is a schematic diagram of the structure of the water pump of the multi-media filter;

[0069] Figure 12 It is a schematic diagram of the structure of the air compressor of the multi-media filter;

[0070] Figure 13 It is a schematic diagram of the structure of the directional suction pipe of the multi-media filter;

[0071] Figure 14 It is a schematic diagram of the external structure of the multi-media filter element of the multi-media filter;

[0072] Figure 15 It is a schematic diagram of the cross-sectional structure of a multi-media filter element of a multi-media filter.

[0073] In the figure: 01, tank body; 1, lower splicing part; 11, support leg; 12, first bolt hole; 13, nozzle; 131, connecting cap; 132, ring pipe; 133, nozzle; 14, connecting plate; 141, connecting hole; 15, bottom pipe; 151, first water quality monitoring sensor; 152, first electric control valve; 2, middle splicing part; 21, control box; 22, mounting plate; 23, mounting hole; 3, upper splicing part; 31, ultrasonic generator; 32, wire; 33, ultrasonic generating terminal; 34, supporting plate; 35, perforation; 36, water inlet pipe; 361, second water quality monitoring sensor; 37, mounting platform; 371, through hole; 38, sewage suction pipe; 4, lifting assembly; 41, drive cylinder; 411, fixing plate; 412, fixing hole; 413, telescopic rod; 414, Pressure plate; 415, pressure cap; 42, connecting plate; 421, first socket hole; 422, second socket hole; 423, first assembly hole; 5, water pump; 51, external pipe; 52, adapter cap; 53, connecting stud; 54, nut; 6, air compressor; 61, fixing foot; 62, second bolt hole; 63, pressure gauge; 64, exhaust pipe; 65, second electric control valve; 7, directional suction pipe; 71, branch pipe; 72, directional suction head; 73, plug ring; 74, assembly plate; 75, second assembly hole; 76, telescopic plug; 77, sealing ring; 8, multi-media filter element; 81, adapter; 82, threaded connection; 83, sealing gasket; 84, guide plate; 85, modified anthracite; 86, fused quartz sand; 87, rare earth permanent magnetic filter material; 88, corrosion-resistant ceramic gravel. DETAILED DESCRIPTION

[0074] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed or detachable connections, mechanical or electrical connections, and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0075] The following is a further description with reference to the accompanying drawings and specific embodiments:

[0076] Example 1

[0077] like Figure 1 and Figure 2 As shown, this embodiment provides a seawater desalination impurity pretreatment process, including coarse filtration, flocculation sedimentation, filter filtration and ultrafiltration, and the filter filtration includes multi-media filter filtration and security filter filtration. Coarse filtration uses a two-stage coarse filtration system composed of a grid filter and a self-cleaning filter. A mechanical grid with a grid pitch of 5-10mm is set at the front end where the seawater enters the pretreatment system. It mainly intercepts large floating objects in the seawater, such as seaweed, shells, plastic fragments, etc., to prevent them from entering subsequent equipment and causing blockage. The seawater after grid filtration enters the self-cleaning filter with a filtration accuracy of 50-100μm, and smaller particulate impurities, such as fine sand and plankton debris, are intercepted by a stainless steel filter or a wedge-shaped filter. The specific steps of flocculation and sedimentation are as follows:

[0078] S100, detect the temperature of the seawater after coarse filtration. When the temperature of the seawater after coarse filtration reaches the set temperature range that is conducive to the flocculation reaction, no heating is required. When the seawater temperature is lower than the set temperature range that is conducive to the flocculation reaction, the waste heat recovered from the evaporated seawater is used to heat the seawater after coarse filtration. Among them, the temperature range that is conducive to the flocculation reaction is 27-32 degrees Celsius. If the temperature is too low, the thermal motion of water molecules will weaken, the hydrolysis rate of the flocculant will slow down, and the flocs formed will be small and loose, with poor sedimentation performance. The dosage needs to be increased to ensure the effect. When it is within the range of 27-32 degrees Celsius, the hydrolysis of the flocculant can be accelerated, and the collision and coagulation of colloidal particles can be promoted. The flocs are formed quickly and have a dense structure, which can effectively improve the sedimentation efficiency. At the same time, the temperature should not be too high. When the temperature is too high, the stability of the flocculant will decrease, or the floc structure will be destroyed due to the excessive movement of water molecules, which will reduce the effect. When the waste heat energy is sufficient, the seawater temperature should be stabilized in a temperature range that is conducive to the flocculation reaction. When the temperature of the seawater after coarse filtration is low and the recovered waste heat is not enough to heat the seawater to a temperature range that is conducive to the flocculation reaction, there are two treatment options: one is to set up another heating structure for heating, and the other is not to set up another heating structure for heating. The choice can be made based on the current seawater quality and comprehensive cost of the sea area.

[0079] S200: Transport the heated seawater to the mixing tank, detect the temperature of the heated seawater, add flocculants according to the dosage corresponding to the temperature, and mix the flocculants with the seawater. The precise addition of flocculants according to the specific temperature of the seawater is based on the significant effect of temperature on the activity of the flocculants: at different temperatures, the hydrolysis rate, molecular diffusion capacity and binding efficiency of the flocculants with colloidal particles vary. If a fixed dosage is added, problems such as insufficient agent at low temperatures and waste of agent at high temperatures are likely to occur. To achieve precise control, the seawater desalination impurity pretreatment system has a built-in temperature-dose comparison table. This table is fitted with a large amount of preliminary experimental data and clearly marks the optimal flocculant dosage corresponding to different temperature ranges.

[0080] S300: The seawater mixed with the flocculant is transported to a flocculation reaction tank for flocculation. The flocculation reaction tank is sequentially arranged with a rapid mixing zone and a slow flocculation zone along the flow direction of the seawater. Both the rapid mixing zone and the slow flocculation zone are equipped with a stirring device. The stirring intensity in the flocculation reaction tank includes the stirring intensity in the rapid mixing zone and the stirring intensity in the slow flocculation zone.

[0081] S400: The seawater after flocculation reaction is transported to the flocculation sedimentation tank for flocculation sedimentation, and the concentration data at different depths of the flocculation sedimentation tank are measured at the same time. Specifically, concentration sensors are set at different depths of the flocculation sedimentation tank, including upper water concentration sensor, middle water concentration sensor and lower water concentration sensor. The upper water concentration sensor is set at 0.5-1 meters below the water surface, and the middle water concentration sensor is set at a depth of 1 meter from the bottom of the tank. within the range of is the depth of the thickening tank, and The lower water concentration sensor is arranged within a range of 0.3-0.8 meters from the bottom of the pool.

[0082] S500: Based on the measurement data and preset rules, one or more of the following parameters are corrected: the flocculant dosage, the flow rate of seawater entering the flocculation sedimentation tank, the agitation intensity of the mixing tank, the residence time of seawater in the flocculation reaction tank, and the agitation intensity within the flocculation reaction tank. The measurement data of the upper water concentration sensor, the middle water concentration sensor, and the lower water concentration sensor are C1, C2, and C3, respectively. The corresponding preset concentration thresholds are upper water concentration threshold T1, middle water concentration threshold T2, and lower water concentration threshold T3. The upper water layer needs to be as clear as possible and have the lowest impurity concentration to reduce the load on subsequent filtration. Therefore, T1 is set as the lowest threshold. The middle water layer lies between the upper clear liquid and the lower sludge layer. A certain concentration of fine flocs or unsettled impurities is permitted, but must be lower than that of the lower layer. Therefore, T2 must be higher than T1. The lower water layer, which holds the majority of settled flocs and sludge, has the highest concentration. However, this concentration must be controlled within a reasonable range to prevent excessive sludge accumulation, which can lead to back-mixing and affect the quality of the supernatant. Therefore, T3 is set as the highest threshold and must be higher than T2. ​​Therefore, T1 < T2 < T3. The upper water concentration thresholds T1, middle water concentration thresholds T2, and lower water concentration thresholds T3 are determined based on the principles of the flocculation and sedimentation process and the target treatment effect, and are fitted using extensive preliminary experimental data.

[0083] When making corrections based on the measurement data and preset rules, the specific correction rules are as follows:

[0084] If C1<T1 and C2<T2, no correction is performed.

[0085] If C3≥T3, immediately open the mud discharge device at the bottom of the flocculation sedimentation tank.

[0086] If C1 < T1 and C2 ≥ T2, the impurity concentration in the upper water layer of the flocculation sedimentation tank is lower than the preset threshold, indicating that relatively clear water has formed in the upper layer and the overall flocculation reaction has not failed globally. However, the impurity concentration in the middle water layer exceeds the standard, which means that the flocs in the middle layer are not fully formed or the structure is loose, causing the formed flocs to be sheared and broken, unable to effectively settle to the lower layer, but suspended in the middle layer. The core contradiction of this stratification phenomenon lies in the mismatch of the stirring intensity in the slow flocculation zone: the core function of slow flocculation is to allow small flocs to gradually collide and merge into large and dense flocs through low-intensity stirring. If the stirring is too strong, it will destroy the polymerization process of the flocs, resulting in the inability of the middle-layer flocs to effectively settle. Therefore, reducing the stirring intensity in the slow flocculation zone is a "symptomatic measure" to directly solve the problem of excessive concentration in the middle layer, and it must be implemented as a priority.

[0087] Therefore, it is necessary to reduce the stirring intensity in the slow flocculation zone by 10%-15%. In order to assist in optimizing the pre-flocculation reaction, one or more of the following adjustment operations can be performed at the same time:

[0088] Increase the stirring intensity of the mixing tank and the stirring speed by 10%-15% to enhance the initial mixing effect of the flocculant and seawater and ensure uniform dispersion of the agent.

[0089] Increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank and increasing the stirring speed by 10%-15% is also to enhance the initial mixing effect of the flocculant and seawater.

[0090] When increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5.

[0091] Reduce the flow rate of seawater entering the flocculation sedimentation tank to 80%-90% of the original flow rate, and promote floc sedimentation by increasing the water's standing or reaction time.

[0092] Prolonging the residence time of seawater in the flocculation reaction tank can be achieved by reducing the water flow rate by 10%-20%. Similarly, increasing the water standing or reaction time can promote floc sedimentation.

[0093] If C1 ≥ T1 and C2 < T2, this phenomenon is relatively rare, but if it occurs, it indicates a special operating condition in which defects occurred in the initial mixing link but the subsequent flocculation growth link is effective. The mixing tank and the rapid mixing zone are the core links of "drug dispersion → colloid destabilization → microflocculation formation" and need to be strengthened at the same time. Therefore, at this time, the stirring intensity of the mixing tank and the stirring intensity of the rapid mixing zone in the flocculation reaction tank should be increased. When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 15%-25%; when the stirring intensity of the rapid mixing zone in the flocculation reaction tank is increased, the stirring speed is increased by 15%-20%. You can also choose to perform one or more of the following adjustment operations at the same time:

[0094] When increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5.

[0095] Reduce the flow rate of seawater entering the flocculation sedimentation tank to 80%-90% of the original flow rate.

[0096] Prolong the residence time of seawater in the flocculation reaction tank and reduce the water flow rate by 10%-20%.

[0097] If C1≥T1, C2≥T2 and C3<T3, it means that the "initial reagent dispersion and colloid destabilization" in the mixing tank and the rapid mixing zone is insufficient, and the "micro-floc aggregation into large flocs" process in the slow flocculation zone is hindered, but the "large floc separation" function of the final sedimentation link is normal (once a large enough floc is formed, it can effectively settle without interference). In short, the front-end mixing is not done well, and the mid-term flocculation has not kept up, but as long as the flocs can grow, the terminal sedimentation will not be greatly affected. At this time, it is necessary to increase the stirring intensity of the mixing tank, increase the stirring intensity of the rapid mixing zone in the flocculation reaction tank, increase the dosage of flocculant, and reduce the stirring intensity of the slow flocculation zone. When increasing the stirring intensity of the mixing tank, the stirring speed is increased by 20%-30%. When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed is increased by 20%-25%. When reducing the stirring intensity of the slow flocculation zone, the stirring speed is reduced by 15%-25%. When increasing the dosage of flocculant, the addition amount is reduced from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: , where k is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5; among them, , .

[0098] Additionally, you can choose to perform one or more of the following adjustments simultaneously:

[0099] Reduce the flow rate of seawater entering the flocculation sedimentation tank to 70%-80% of the original flow rate.

[0100] Prolong the residence time of seawater in the flocculation reaction tank; reduce the water flow rate by 15%-25%.

[0101] If C1≥T1, C2≥T2 and C3≥T3, the entire "mixing-flocculation-sedimentation" process of the flocculation sedimentation process in the manual fails, and "systematic emergency intervention" needs to be initiated. At this time, the core of the processing logic is to simultaneously repair the defects in each link and prevent the system from crashing. At this time, the stirring intensity of the mixing tank should be increased, the stirring intensity of the rapid mixing zone in the flocculation reaction tank should be increased, the dosage of the flocculant should be increased, the stirring intensity of the slow flocculation zone should be reduced, the flow rate of seawater entering the flocculation sedimentation tank should be reduced, the residence time of seawater in the flocculation reaction tank should be extended, and the sludge discharge device at the bottom of the flocculation sedimentation tank should be immediately opened, and the sludge discharge speed should be increased. When increasing the stirring intensity of the mixing tank, the stirring speed is increased by 30%-35%. When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed is increased by 25%-30%. When increasing the dosage of flocculant, the addition amount is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.1-0.2; when hour, Take 0.2-0.3; when hour, Take 0.3-0.4; when hour, Take 0.5-0.6; among them, , , When reducing the agitation intensity in the slow flocculation zone, reduce the agitation speed by 20%-30%. When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 60%-70% of the original flow rate. When extending the residence time of seawater in the flocculation reaction tank, reduce the water flow rate by 20%-30%. When opening the mud discharge device at the bottom of the flocculation sedimentation tank, increase the speed of the mud discharge pump by 50% and increase the operating frequency of the scraper motor by 10%-15%.

[0102] Filter filtration includes multi-media filter filtration and security filter filtration, which use media filters and security filters respectively. The security filter is the last barrier before ultrafiltration and uses PP cotton or pleated filter elements with a precision of 5-20μm to intercept trace particles that have not been removed by the previous process to prevent them from entering the ultrafiltration membrane and causing scratches or blockages.

[0103] The ultrafiltration step uses a hollow fiber ultrafiltration membrane with a pore size of 0.01-0.1μm and an operating pressure of 0.1-0.3MPa. During the ultrafiltration process, air-water backwashing is performed every 30-60 minutes, and the backwashing time is 3-5 minutes; when the membrane flux drops to 70%-80% of the initial value, the chemical cleaning program is started, and a citric acid solution with a mass fraction of 2%-3% or a sodium hydroxide solution with a mass fraction of 0.5%-1% is used for circulating cleaning, and the cleaning time is 60-90 minutes.

[0104] In summary, the desalination impurity pretreatment process provided by the present invention addresses the significant impact of seawater temperature on the flocculation reaction. By utilizing the residual heat from evaporation of desalinated seawater to heat the coarsely filtered seawater, the temperature of the seawater entering the flocculation and sedimentation process is stabilized within a temperature range favorable for the flocculation reaction, or closer to a temperature range favorable for the flocculation reaction. This effectively improves the hydrolysis efficiency and activity of the flocculant, thereby enhancing the flocculant's effectiveness. Furthermore, the flocculant dosage is precisely matched to the real-time water temperature, avoiding waste or insufficient flocculant due to temperature fluctuations. In addition, by setting concentration sensors at different depths in the flocculation sedimentation tank, a stratified monitoring system for different depths of the flocculation sedimentation tank is constructed, and a dynamic feedback adjustment mechanism based on the seawater concentration at different depths of the flocculation sedimentation tank is established. When the detection data shows that the flocculation sedimentation effect deviates from expectations, key parameters such as the flocculant dosage, the flow rate of seawater entering the flocculation sedimentation tank, the stirring intensity of each reaction area and the seawater residence time are automatically optimized and corrected, effectively ensuring the stability and efficiency of the flocculation sedimentation effect, and providing water inlet conditions with stable water quality and low impurity content for subsequent treatment processes, effectively reducing the load of subsequent treatment processes.

[0105] Example 2

[0106] like Figure 3As shown, this embodiment provides a seawater desalination impurity pretreatment system for implementing the seawater desalination impurity pretreatment process provided in Example 1. The seawater desalination impurity pretreatment system includes a coarse filtration module, a flocculation and sedimentation module, a filter module, an ultrafiltration module, a control system module, and a pipeline and valve system module. The coarse filtration module includes a grid filter and a self-cleaning filter. A mechanical grid with a grid pitch of 5-10mm is set at the front end of the seawater entering the pretreatment system. It mainly intercepts large floating objects in the seawater, such as seaweed, shells, and plastic fragments, to prevent them from entering subsequent equipment and causing blockage. The seawater after grid filtration enters the self-cleaning filter with a filtration accuracy of 50-100μm. Smaller particulate impurities, such as fine sand and plankton debris, are intercepted by a stainless steel filter or a wedge-shaped filter. At the same time, the self-cleaning filter has a timed or fixed pressure differential automatic cleaning function. When the filter screen intercepts too many impurities and the pressure differential reaches the set value, or the operating time reaches the preset cleaning cycle, the backwash program will automatically start, and the trapped impurities will be flushed out by reverse water flow to ensure filtration efficiency and continuity.

[0107] The filter module consists of a multi-media filter and a safety filter. The safety filter, serving as a backup for the multi-media filter, utilizes a higher-precision filter element to effectively intercept fine particles leaking from the multi-media filter, preventing them from entering the ultrafiltration module and damaging the ultrafiltration membrane. The ultrafiltration module includes an ultrafiltration membrane assembly, which utilizes an ultrafiltration membrane with an appropriate molecular weight cutoff. The membrane material possesses excellent chemical stability and mechanical strength, enabling deep filtration of previously treated seawater. Its operating principle is based on the membrane's sieving effect. As seawater flows under pressure through the membrane, impurities such as fine colloids, microorganisms, and large organic molecules are trapped, unable to pass through the membrane pores. The remaining impurities that pass through the membrane are the higher-quality filtrate, further enhancing the seawater's purity and providing high-quality feed water for subsequent desalination processes such as reverse osmosis. The ultrafiltration module performs deep filtration on previously treated seawater, intercepting impurities such as fine colloids and microorganisms, further improving water quality.

[0108] The flocculation and sedimentation module includes a seawater temperature detection unit, a heating unit, a mixing tank unit, a flocculation reaction tank unit, and a flocculation sedimentation tank unit. The seawater temperature detection unit includes an inlet temperature sensor and an outlet temperature sensor. These sensors utilize thermistors or thermocouples to accurately detect seawater temperature in real time. The inlet temperature sensor is installed in the pipe between the coarse filter module outlet and the heating unit inlet to detect the temperature of the seawater discharged from the coarse filter module. The outlet temperature sensor, installed in the heating unit outlet pipe, detects the temperature of the seawater after heating in the heating unit, providing accurate temperature data for the control system module to control the heating unit.

[0109] The heating unit is used to heat the seawater discharged from the coarse filtration module. The heating unit includes multiple plate heat exchangers. According to the seawater temperature data fed back by the inlet water temperature detection sensor and the preset temperature range that is conducive to the flocculation reaction, the control system module regulates the hot water temperature and heat exchange area to heat the seawater to a suitable temperature, creating good temperature conditions for the subsequent flocculation reaction. The mixing tank module includes a mixing tank and a flocculant addition system. The mixing tank is provided with a stirring device. The flocculant addition system is equipped with a precise metering pump, a flocculant storage tank and a stirring device for adding flocculants to the mixing tank. The flocculation reaction tank unit includes a rapid mixing zone and a slow flocculation zone arranged in sequence along the direction of coastal water flow. A stirring device is provided in both the rapid mixing zone and the slow flocculation zone. A guide plate is set between the fast mixing zone and the slow flocculation zone. The guide plate adopts a broken line structure design with a bending angle range of 120°-150°. It can not only effectively change the direction of water flow to form turbulence to promote the full mixing of the agent and seawater, but also avoid the flocs from being broken due to violent collisions, and ensure a smooth transition from the fast mixing zone to the slow flocculation zone. The flocculation sedimentation tank unit includes a flocculation sedimentation tank. There are multiple concentration sensors in the flocculation sedimentation tank, including an upper water concentration sensor, a middle water concentration sensor and a lower water concentration sensor. The upper water concentration sensor is set at 0.5-1 meters below the water surface, and the middle water concentration sensor is set at a distance from the bottom of the tank. within the range of is the depth of the thickening tank, and The lower water concentration sensor is set within 0.3-0.8 meters from the bottom of the tank. In addition, the flocculation sedimentation tank is also equipped with a sludge scraping and sludge removal system including a sludge discharge pump, sludge discharge pipe, sludge discharge valve, and a sludge scraper. The drive motors of the sludge discharge pump and sludge scraper use variable frequency motors.

[0110] like Figure 3 As shown, the control system module is used to be electrically connected to the coarse filtration module, the flocculation and sedimentation module, the filter module, the ultrafiltration module, and the pipeline and valve system module. The control system module uses a PLC controller or a microprocessor as the control core, collects data transmitted from each module in real time, and performs corresponding adjustments based on preset algorithms and threshold judgments to achieve full-process closed-loop control such as temperature adaptation, precise addition of flocculants, dynamic adjustment of stirring intensity, and stratified concentration feedback optimization correction in the seawater desalination impurity pretreatment process provided in Example 1, thereby ensuring efficient impurity removal and stable operation of subsequent treatment units.

[0111] like Figure 3As shown, the pipeline and valve system module is used to connect the coarse filtration module, flocculation and sedimentation module, filter module, and ultrafiltration module to form a complete seawater transportation path. The pipeline and valve system module is equipped with an electronically controlled regulating valve on the connecting pipeline between the coarse filtration module and the flocculation and sedimentation module. This valve is used to regulate the flow of seawater entering the flocculation and sedimentation module under the control of the control system module. An electronically controlled regulating valve is installed on the pipeline between the flocculation reaction tank unit and the flocculation sedimentation tank unit. This valve is used to adjust the flow rate of seawater entering the flocculation sedimentation tank under the control of the control system module. The electronically controlled regulating valve can use an electric regulating ball valve or butterfly valve, equipped with a high-precision electric actuator, which can accurately adjust the opening under the control of the control system module.

[0112] like Figure 4 、 Figure 5 、 Figure 9 and Figure 15 As shown, the multi-media filter includes a tank body 01, a lifting assembly 4, a water pump 5, a directional suction pipe 7 and a multi-media filter element 8. The tank body 01 includes a lower splicing part 1, a middle splicing part 2 and an upper splicing part 3. The lower splicing part 1, the middle splicing part 2 and the upper splicing part 3 are spliced ​​and connected in sequence from bottom to top. This structure of the tank body 01 facilitates the assembly of the tank body 01 and also facilitates the inspection or replacement of the various components inside the tank body 01. A sewage suction pipe 38 is provided in the middle of the top of the upper splicing part 3. The sewage suction pipe 38 is convenient for use with the water pump 5. During backwashing, the water pump 5 and the directional suction pipe 7 can generate suction on the multi-media filter element 8 to better absorb the dirt inside the multi-media filter element 8. An ultrasonic generator 31 is installed at the edge of the upper joint 3. This generator facilitates the emission of ultrasonic waves into the multi-media filter element 8 during backwashing. When emitted downward from the top, the ultrasonic waves propagate perpendicularly to the stacking direction of the filter media layers (such as quartz sand and anthracite), penetrating the gaps between the multiple layers. During backwashing, water flows upward from the bottom, coupling in opposite directions with the ultrasonic waves directed downward from the top. This synergistic effect of "upward water flow + downward ultrasonic waves" more effectively removes contaminants adhering to the media surface. However, ultrasonic waves mounted on the side, directed perpendicularly to the water flow, make it difficult to achieve an efficient energy superposition effect.

[0113] Lifting assembly 4 is mounted on the top of upper joint 3, with the output end of lifting assembly 4 inserted into tank body 01. The water suction end of water pump 5 is connected to suction pipe 38, while the bottom end of water pump 5 is connected to upper joint 3. A directional suction pipe 7 is plugged into suction pipe 38, and its side is connected to the output end of lifting assembly 4. Lifting assembly 4 is used to move directional suction pipe 7 up and down. This structure facilitates the use of water pump 5, allowing it to cooperate with suction pipe 38 to absorb dirt from the filter element, thereby improving the cleaning effect of the filter element. Furthermore, directional suction pipe 7 can directionally absorb the multi-media filter element 8, avoiding waste of suction force, which further improves the filtration efficiency of the multi-media filter element 8.

[0114] Multiple multi-media filter elements 8 are evenly arranged inside the middle joint 2. Deflectors 84 are installed at the top and bottom of the multi-media filter elements 8, as well as between adjacent filter media. These deflector plates 84 are uniformly provided with diversion holes. Each hole has a different diameter, and the diameters of the holes in these deflector plates 84 decrease from top to bottom. When water enters the filter from the water inlet, if the deflector plates 84 have the same diameter, the water will be concentrated in the center of the tank 01 due to inertia, forming a "bunching effect" (similar to the flow pattern of a fountain). The upper large-aperture deflector plates 84 initially disperse the water flow, while the lower small-aperture deflector plates 84 further constrain the water flow path, ensuring that the water evenly covers the entire filter cross-section. As the water flows downward, the amount of impurities retained by the filter media layer gradually increases, resulting in increased resistance. By reducing the aperture of the guide holes along the water flow direction, the upper guide plate 84 can distribute more flow (large aperture reduces local resistance), and the lower guide plate 84 compensates for the resistance difference through the small aperture, ultimately achieving balanced utilization of the entire layer of filter media.

[0115] For example, when the upper medium intercepts impurities and causes the resistance to increase by 15%, the small aperture of the lower guide plate 84 can reduce the local flow rate by 8%, maintaining the overall flow stability. And the upper large-aperture guide plate 84 allows larger particle impurities to pass through, avoiding the formation of "filter cake" blockage on the surface. The lower small-aperture guide plate 84 intercepts fine particles to achieve graded filtration. If the aperture of the bottom guide plate 84 is too large, the high-speed water flow during backwashing may lift the upper fine particle medium, causing the medium to mix or lose. A stable water flow support layer can be formed by the bottom small-aperture guide plate 84 to ensure the stability of the medium layer during backwashing. The aperture d of the guide hole satisfies the following formula: in, is the initial aperture of the top guide plate, is the aperture attenuation coefficient, It is the height of the guide plate from the top of the filter medium layer.

[0116] The guide plate 84 is made of corrosion-resistant high-strength plastic or metal alloy; the thickness of the guide plate 84 is Determined according to the following formula: in, is the maximum pressure the guide plate can withstand, is the span of the deflector, is the allowable stress of the material, is the width of the deflector.

[0117] like Figure 6As shown, a plurality of legs 11 are evenly arranged on the bottom edge of the lower joint 1, and a first bolt hole 12 is provided at the bottom end of the legs 11; the legs 11 are used to support the entire filter, and the first bolt hole 12 is used to fix the entire filter with bolts. A bottom pipe 15 is provided at the bottom end of the lower joint 1. The end of the bottom pipe 15 is in a T-shaped structure, and two openings are provided at the end of the bottom pipe 15, serving as the clean water outlet and the backwash water inlet respectively; a first water quality monitoring sensor 151 is provided on the bottom pipe 15, and the first water quality monitoring sensor 151 is used to monitor the water quality at the outlet. Both openings at the end of the bottom pipe 15 are connected to a first electrically controlled valve 152. The bottom pipe 15 is responsible for discharging the purified water, and is also used to facilitate the introduction of backwash water during backwashing. The first electrically controlled valve 152 is used to control the two openings of the bottom pipe 15 separately, making it convenient to close the backwash water inlet when discharging the clean water, and to close the clean water outlet during backwashing.

[0118] like Figure 5 、 Figure 7 and Figure 9 As shown, a mounting plate 22 is provided on the inner side of the middle joint 2 near the top and bottom ends. Multiple mounting holes 23 are evenly arranged on the mounting plate 22, and the inner side of the mounting hole 23 at the top of the inner side of the middle joint 2 is provided with an internal thread. The mounting holes 23 are convenient for installing the multi-media filter element 8. This structure ensures that seawater can only flow from the top of the middle joint 2 to the bottom through the multi-media filter element 8, facilitating effective filtration of seawater. At the same time, this structure also facilitates the individual replacement of each multi-media filter element 8, avoiding the problem of difficult replacement of the media in traditional multi-media filters and greatly improving the flexibility of the multi-media filter. A control box 21 is provided on the side of the middle joint 2. The control box 21 is used to connect to various electronic control components to control the entire filter, facilitating the operation and use of the entire filter. Connecting plates 14 are provided at both ends of the middle splicing part 2, the top of the lower splicing part 1 and the bottom of the upper splicing part 3. A plurality of connecting holes 141 are evenly provided on the connecting plates 14. Adjacent connecting plates 14 are connected by bolts. This structure facilitates the stable connection between the entire tank body 01, and the two ends of the middle splicing part 2, the top of the lower splicing part 1 and the upper splicing part 3 are sealed to avoid water leakage.

[0119] like Figure 9As shown, ultrasonic generating terminals 33 are provided on both sides of the sewage suction pipe 38, and the ultrasonic generator 31 and the ultrasonic generating terminals 33 are connected by wires 32; this structure is convenient for cooperating with the ultrasonic generator 31 to emit ultrasonic waves, so as to facilitate better cleaning of dirt in the multi-media filter element 8 during backwashing. A support plate 34 is provided on one side of the top of the upper splicing part 3, and a perforation 35 is provided on the support plate 34. The cooperation between the support plate 34 and the perforation 35 is convenient for installing the water pump 5 and facilitating the operation of the water pump 5. A water inlet pipe 36 is provided on the other side of the upper splicing part 3, and a second water quality monitoring sensor 361 is provided on the water inlet pipe 36. The second water quality monitoring sensor 361 is convenient for monitoring the water quality of seawater at the water inlet pipe 36. A first electrically controlled valve 152 is provided at the end of the water inlet pipe 36; the first electrically controlled valve 152 is convenient for controlling the opening and closing of the water inlet pipe 36. The upper joint 3 is provided with a mounting platform 37 along one side of the sewage suction pipe 38. A through hole 371 is provided in the middle of the mounting platform 37 for the output end of the lifting assembly 4 to pass through the upper joint 3, facilitating the stable use of the lifting assembly 4 and the sealing connection between the lifting assembly 4 and the upper joint 3. An ultrasonic generator is installed on the top of the tank body. The ultrasonic generator emits high-frequency ultrasonic waves during the backwash process; the power of the ultrasonic wave emitted by the ultrasonic generator 31 is Determined according to the following formula:

[0120] in, is the power coefficient, is the density of seawater, is the effective volume of the filter tank, is the change in impurity concentration in seawater before and after backwashing, is the backwash time.

[0121] like Figure 10As shown, the lifting assembly 4 includes a drive cylinder 41 and a connecting plate 42. The drive cylinder 41 can be an electric cylinder, a pneumatic cylinder, or a hydraulic cylinder. It facilitates the up and down movement of the directional suction pipe 7 by the drive cylinder 41. Fixed plates 411 are provided on both sides of the drive cylinder 41. The fixed plates 411 are provided with multiple fixing holes 412. The two fixing plates 411 engage with both sides of the mounting platform 37. The drive cylinder 41 is fixed to the mounting platform 37 by bolts passing through the fixing holes 412. This structure ensures that the drive cylinder 41 is stably connected to the mounting platform 37, facilitating stable use of the drive cylinder 41. A telescopic rod 413 is provided at the output end of the driving cylinder 41, and the telescopic rod 413 passes through the through hole 371, and a pressure plate 414 is provided at the bottom end of the telescopic rod 413, and a stud is provided at the bottom end of the pressure plate 414, and a pressure cap 415 is provided on the stud. A first socket hole 421 is provided at one end of the connecting plate 42, and the stud passes through the first socket hole 421. The pressure cap 415 is arranged at the end of the stud passing through the first socket hole 421, and the pressure cap 415 is pressed tightly on the connecting plate 42; this structure facilitates the stable connection of the driving cylinder 41 with the connecting plate 42, and facilitates the installation and use of the connecting plate 42. A second sleeve hole 422 is provided at the other end of the connecting plate 42, and the second sleeve hole 422 is sleeved on the directional suction pipe 7. A plurality of first assembly holes 423 are evenly provided along the edge of the second sleeve hole 422 of the connecting plate 42, which are used to connect the connecting plate 42 with the directional suction pipe 7, thereby facilitating the upward and downward movement of the directional suction pipe 7 by the extension and contraction of the driving cylinder 41, and facilitating the raising of the directional suction pipe 7 when backwashing is not performed, and driving the downward suction pipe to be pressed downward when backwashing is performed, so that the directional suction pipe 7 is connected to the multi-media filter element 8.

[0122] like Figure 11 As shown, the output end of the water pump 5 is provided with two external pipes 51, each with an adapter cap 52 at the end. The two external pipes 51 serve as the water suction end and the discharge end of the water pump 5, respectively, facilitating connection of the water pump 5 to the sewage suction pipe 38 and the external sewage discharge pipe. A connecting stud 53 is provided at the bottom end of the water pump 5. The connecting stud 53 is installed through the through-hole 35, and a nut 54 is provided at one end of the connecting stud 53 that passes through the through-hole 35. The nut 54 is pressed against the support plate 34, facilitating the stable installation of the water pump 5 on the support plate 34.

[0123] like Figure 13As shown, the directional suction pipe 7 is provided with multiple branch pipes 71, and the bottom end of each branch pipe 71 is provided with a directional suction head 72 aligned with the multi-media filter element 8. The bottom end of the directional suction head 72 is provided with an insert ring 73, and the directional suction head 72 can be inserted into the top of the multi-media filter element 8 when it moves downward. This structure ensures that each directional suction head 72 is inserted into the top of the multi-media filter element 8, so that the multi-media filter element 8 can be directly adsorbed. In combination with the backwashing water flow, the backwashing effect of the multi-media filter element 8 can be accelerated, greatly facilitating the cleaning of the multi-media filter element 8. The top of the directional suction pipe 7 is provided with a telescopic insert 76, and the top of the side of the telescopic insert 76 is provided with multiple sealing rings 77. The top of the telescopic insert 76 is inserted into the bottom inner side of the sewage suction pipe 38 to facilitate the up and down movement of the directional suction pipe 7. An assembly plate 74 is provided at the top side of the directional straw 7, and a plurality of second assembly holes 75 are provided on the assembly plate 74. The second assembly holes 75 are aligned with the first assembly holes 423, and the assembly plate 74 and the connecting plate 42 are connected by bolts, which facilitates the connection of the directional straw 7 to the lifting component 4 and facilitates the lifting component 4 to drive the directional straw 7 to move up and down and be used.

[0124] like Figure 14 and Figure 15 As shown, a connector 81 is provided at the top of the multi-media filter element 8, and a threaded connection portion 82 is provided on the side of the multi-media filter element 8 below the connector 81. The threaded connection portion 82 is threadedly connected to the mounting hole 23 at the top of the intermediate joint 2. This structure facilitates the flexible disassembly and assembly of the multi-media filter element 8 and facilitates the replacement of the multi-media filter element 8. A sealing gasket 83 is provided at the bottom of the side of the multi-media filter element 8. The sealing gasket 83 is squeezed inside the mounting hole 23 at the bottom of the intermediate joint 2 to achieve the purpose of sealing between the multi-media filter element 8 and the intermediate joint 2. The media inside the multi-media filter element 8 are provided, from top to bottom, with modified anthracite 85, fused quartz sand 86, rare earth permanent magnetic filter material 87, and corrosion-resistant ceramic gravel 88. The filter media of this structure can filter seawater more efficiently. The specific parameters of each filter media are shown in Table 1.

[0125] Table 1

[0126] dielectric layer Material Particle size Layer thickness Operating parameters upper layer Modified anthracite 1.5-2.0mm 350mm Backwash intensity 15L / (m²・s), frequency 8h Middle level Fused quartz sand 0.6-1.0mm 600mm Filtration flow rate 8-10m / h Lower level Rare earth permanent magnetic filter media 0.3-0.5mm 250mm Magnetic field strength 0.3T Support layer Corrosion-resistant ceramic gravel 2-16mm 250mm Water distribution uniformity error <5%

[0127] like Figure 4 and Figure 6As shown, it also includes an air compressor 6, a nozzle 13 is provided on the side of the lower splicing part 1, and a connecting cap 131 is provided at the end of the nozzle 13 facing outward. The connecting cap 131 is connected to the exhaust end of the air compressor 6, which facilitates the air compressor 6 to eject gas through the nozzle 13, thereby achieving the purpose of gas-water mixing backwashing. The synergistic effect of compressed air and backwashing water shows significant advantages in improving cleaning efficiency, reducing energy consumption, and protecting filter media. An annular tube 132 is connected to the end of the nozzle 13 facing the inner side of the lower splicing part 1, and a nozzle 133 is provided on the annular tube 132 and the nozzle 13 at the position aligned with the multi-media filter element 8. A one-way valve is provided at the bottom of the nozzle 133 to ensure that the intelligent gas is ejected from the nozzle 133 and water cannot flow back into the annular tube 132 and the inner side of the nozzle 13 through the nozzle 133.

[0128] like Figure 12 As shown, the bottom of the air compressor 6 is equipped with multiple fixing legs 61, each of which is provided with a second bolt hole 62, which facilitates the fixing of the air compressor 6 with bolts, thus facilitating its use. A pressure gauge 63 is provided at the outlet of the air compressor 6 to conveniently measure the air pressure within the tank 01 of the air compressor 6. Furthermore, the outlet of the air compressor 6 is connected to an exhaust pipe 64, which is equipped with a second electrically controlled valve 65 for controlling the opening and closing of the exhaust pipe 64, facilitating airflow during backwashing.

[0129] like Figure 8As shown, the control box 21 has a microprocessor integrated inside, and the microprocessor is connected to a data acquisition module, a backwash control module, a communication module, a power supply module, and an ultrasonic control module; the control box 21 is electrically connected to the first solenoid valve, the second solenoid valve, the first water quality monitoring sensor 151, the second water quality monitoring sensor 361, the water pump 5, and the drive cylinder 41; the microprocessor facilitates the processing of data from the entire filter, and the data acquisition module is used to cooperate with the first water quality monitoring sensor 151 and the second water quality monitoring sensor 361 to monitor the water quality of the water inlet and outlet, and to monitor the turbidity, suspended matter content, and other water quality parameters of the seawater in real time. The control box 21 automatically adjusts the filtration and backwash procedures according to the preset water quality standards and parameter ranges. For example, when the water quality at the outlet does not meet the standards, the control box 21 automatically starts the backwash procedure; when the inlet water quality is good, the filtration cycle is appropriately extended to improve the operating efficiency of the equipment. The backwash control module is used to control the opening of the backwash water inlet and close the clean water outlet at the same time to facilitate the backwash procedure. The communication module is used to connect to the terminal device to facilitate the real-time feedback of the filter operation data to the terminal device. The power module is used to connect to the power supply, thereby facilitating the power supply to each component. The ultrasonic control module is used to control the operation of the ultrasonic generator 31, so that the ultrasonic generator 31 can be started during backwashing to facilitate better cleaning of the multi-media filter element 8. The first water quality monitoring sensor 151 and the second water quality monitoring sensor 361 monitor the water quality at the water inlet and outlet of the tank body 01 respectively. The control box 21 automatically adjusts the filtration and backwash procedures according to the preset water quality standards and parameter ranges; the filtration cycle Calculated according to the following formula:

[0130] in, is the baseline filtration cycle, is the water quality parameter value of the water inlet, is the preset water quality standard value, is the decay constant.

[0131] like Figure 4 and Figure 5 As shown, the sidewalls of the lower joint 1, the middle joint 2, and the upper joint 3 are all hollow, and the hollow space is provided as a thermal insulation interlayer filled with thermal insulation material. This not only reduces heat loss and maintains a stable water temperature during filtration, which is beneficial for improving filtration efficiency, but also enhances the structural strength of the tank body 01 to a certain extent.

[0132] Working Principle: During use, the entire filter is assembled and secured in the designated position, connecting it to the various pipes. When filtering seawater, the lifting assembly 4 raises the directional suction pipe 7, opening the top opening of the multi-media filter element 8. Seawater is then injected into the tank 01 through the water inlet pipe 36. The seawater then flows through the multi-media filter element 8 and through the intermediate joint 2. The purified seawater then flows out of the tank 01 through the clean water outlet of the bottom pipe 15. Multiple guide plates 84 are positioned from top to bottom within the multi-media filter element 8, ensuring uniform water flow through each layer of the media, improving the filtration efficiency and facilitating even filtration of the seawater. After the multi-media filter element 8 has been used for a period of time, when the first water quality monitoring sensor 151 detects that the water quality at the water outlet is not up to standard, the control box will control the first solenoid valve at the clean water outlet of the bottom pipe 15 to close, and open the first solenoid valve at the backwash water inlet, so that the backwash water enters the tank body 01 through the bottom pipe 15. At the same time, the lifting component 4 will drive the directional suction pipe 7 to press down, so that the directional suction head 72 is inserted into the opening at the top of the multi-media filter element 8, and then the water pump 5 and the ultrasonic generator 31 will operate. After the water pump 5 operates, it will generate suction on the multi-media filter element 8, which can force the dirt inside the multi-media filter element 8 and the backwash water to flow quickly out of the multi-media filter element 8, thereby achieving the purpose of cleaning the inside of the multi-media filter element 8, and the ultrasonic wave emitted by the ultrasonic generator 31 can make the dirt attached to the multi-media filter element 8 quickly separate from the medium, which can further improve the cleaning effect of the multi-media filter element 8. The wastewater generated by backwashing is directed by multiple directional suction heads 72 to the directional suction pipe 7 for confluence. Once confluence is complete, it is discharged from the outlet of the water pump 5 into the sewage pipe, effectively cleaning the multi-media filter element 8. During the backwash process, the second solenoid valve can be opened, allowing the air compressor 6 to supply air to the nozzle 13, achieving an air-water mixed backwash. This releases compressed air into the water, forming countless tiny bubbles. These bubbles, carried by the water flow, burst near the filter media surface, generating localized high pressure and intense shock waves that instantly strip away stubborn contaminants (such as colloids and microbial membranes) trapped within the media pores. This cavitation effect, combined with the shear force of the water flow, increases contaminant removal efficiency by 40%-60% (compared to traditional water backwashing, which relies solely on shear). Furthermore, the turbulent flow generated by the rising bubbles disrupts the two-dimensional laminar flow of the water backwash, forming complex turbulent vortices. This turbulent motion allows the backwash media flow to penetrate deep into the filter layer pores, cleaning corners that are difficult to reach with traditional water backwashing.

[0133] In summary, the multi-media filter provided by the present application utilizes multiple removable multi-media filter elements 8 within the tank body 01 to effectively filter impurities from seawater. Guide plates 84 are provided at both ends of the multi-media filter element 8 and between adjacent layers of media. Guide plates 84 are uniformly provided with guide holes of varying diameters, with the diameters gradually decreasing along the direction of water flow. This structure allows water to flow evenly through each layer of media, improving the seawater purification effect. Furthermore, a water pump 5 is provided at the top of the tank body 01 for use with a directional suction pipe 7. During backwashing, the directional suction pipe 7 is inserted into the top of the filter element to achieve negative pressure suction on the filter element. This increases the speed with which backwash water flows through the multi-media filter element 8, facilitating faster and more effective impurity removal from the multi-media filter element 8. An ultrasonic generator 31 is provided at the top of the upper joint 3 to emit ultrasonic waves in the opposite direction of the backwash water flow. During backwashing, the water flows upward from the bottom, forming a counter-coupling with the ultrasonic waves directed downward from the top. This synergistic effect of "upper water flow + lower ultrasound" can more effectively remove contaminants attached to the surface of the media. By providing a nozzle 13 inside the lower splicing portion 1, a jet connector at the top of the nozzle 13, and an air compressor 6 connected to the outside of the nozzle 13, the jet connectors are aligned with each multimedia filter element 8. This creates a water-air mixed backwashing method, which improves the effective cleaning of the multimedia filter element 8 and extends the service life of the multimedia filter element 8.

[0134] The above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A seawater desalination impurity pretreatment process, comprising coarse filtration, flocculation sedimentation, filter filtration and ultrafiltration, characterized in that: The specific steps of flocculation and sedimentation are as follows: S100, detecting the temperature of the seawater after coarse filtration. When the seawater temperature is lower than a set temperature range conducive to flocculation reaction, using waste heat recovered from evaporating the seawater to heat the coarsely filtered seawater. When the waste heat energy is sufficient, the seawater temperature is stabilized in a temperature range conducive to flocculation reaction. S200, transporting the heated seawater to a mixing tank, detecting the temperature of the heated seawater, adding a flocculant according to a dosage corresponding to the temperature, and mixing the flocculant with the seawater; S300, transporting the seawater mixed with the flocculant to a flocculation reaction tank for flocculation reaction; S400, transporting the seawater after the flocculation reaction to a flocculation sedimentation tank for flocculation sedimentation, and simultaneously measuring concentration data at different depths of the flocculation sedimentation tank; S500, correcting one or more of the following based on the measurement data and preset rules: the dosage of the flocculant, the flow rate of the seawater entering the flocculation sedimentation tank, the stirring intensity of the mixing tank, the residence time of the seawater in the flocculation reaction tank, and the stirring intensity in the flocculation reaction tank; The flocculation reaction tank is provided with a rapid mixing zone and a slow flocculation zone in sequence along the flow direction of seawater. A stirring device is provided in both the rapid mixing zone and the slow flocculation zone. The stirring intensity in the flocculation reaction tank includes the stirring intensity of the rapid mixing zone and the stirring intensity of the slow flocculation zone. Concentration sensors are set at different depths of the flocculation sedimentation tank, including an upper layer water concentration sensor, a middle layer water concentration sensor, and a lower layer water concentration sensor; the measurement data of the upper layer water concentration sensor, the middle layer water concentration sensor, and the lower layer water concentration sensor are C1, C2, and C3, respectively, and the corresponding preset concentration thresholds are T1, T2, and T3, respectively, and T1 < T2 < T3; If C1<T1 and C2<T2, no correction is performed; If C3 ≥ T3, immediately open the mud discharge device at the bottom of the flocculation sedimentation tank; If C1 < T1 and C2 ≥ T2, then reduce the stirring intensity of the slow flocculation zone, and simultaneously select to perform one or more of the following adjustment operations: increase the stirring intensity of the mixing tank, increase the stirring intensity of the fast mixing zone in the flocculation reaction tank, increase the dosage of the flocculant, reduce the flow rate of seawater entering the flocculation sedimentation tank, and extend the residence time of seawater in the flocculation reaction tank; If C1 ≥ T1 and C2 < T2, then increase the stirring intensity of the mixing tank and the stirring intensity of the rapid mixing zone in the flocculation reaction tank, and simultaneously select to perform one or more of the following adjustment operations: increase the dosage of flocculant, reduce the flow rate of seawater entering the flocculation sedimentation tank, and extend the residence time of seawater in the flocculation reaction tank; If C1 ≥ T1 and C2 ≥ T2, then: When C3 < T3, increase the stirring intensity of the mixing tank, increase the stirring intensity of the fast mixing zone in the flocculation reaction tank, increase the dosage of flocculant, reduce the stirring intensity of the slow flocculation zone, and simultaneously select to perform one or more of the following adjustment operations: reduce the flow rate of seawater entering the flocculation sedimentation tank, and extend the residence time of seawater in the flocculation reaction tank; When C3≥T3, increase the stirring intensity of the mixing tank, increase the stirring intensity of the fast mixing zone in the flocculation reaction tank, increase the dosage of flocculant, reduce the stirring intensity of the slow flocculation zone, reduce the flow rate of seawater entering the flocculation sedimentation tank, extend the residence time of seawater in the flocculation reaction tank, and immediately open the sludge discharge device at the bottom of the flocculation sedimentation tank and increase the sludge discharge speed.

2. A seawater desalination impurity pretreatment process according to claim 1, characterized in that: The upper water concentration sensor is set at 0.5-1 meters below the water surface, and the middle water concentration sensor is set at a distance from the bottom of the pool. - within the range of is the depth of the thickening tank, and ≥3 meters, the lower water concentration sensor is set within the range of 0.3-0.8 meters from the bottom of the pool.

3. A seawater desalination impurity pretreatment process according to claim 1, characterized in that: Based on different concentration data combinations, the specific quantitative correction methods for each process parameter are as follows: If C1<T1 and C2≥T2: When reducing the stirring intensity in the slow flocculation zone, the stirring speed is reduced by 10%-15%; When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 10%-15%; When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed increases by 10%-15%; When increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5; When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 80%-90% of the original flow rate; When the residence time of seawater in the flocculation reaction tank is extended, the inlet flow rate is reduced by 10%-20%; If C1 ≥ T1 and C2 < T2: When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 15%-25%; When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed increases by 15%-20%; When increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5; When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 80%-90% of the original flow rate; When the residence time of seawater in the flocculation reaction tank is extended, the inlet flow rate is reduced by 10%-20%; If C1≥T1, C2≥T2 and C3<T3: When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 20%-30%; When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed increases by 20%-25%; When reducing the stirring intensity in the slow flocculation zone, the stirring speed is reduced by 15%-25%; When increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.05-0.1; when hour, Take 0.1-0.15; when hour, Take 0.2-0.3; when hour, Take 0.4-0.5; among them, , ; When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 70%-80% of the original flow rate; When the residence time of seawater in the flocculation reaction tank is extended, the inlet flow rate is reduced by 15%-25%; If C1 ≥ T1, C2 ≥ T2 and C3 ≥ T3: When the stirring intensity of the mixing tank is increased, the stirring speed is increased by 30%-35%; When increasing the stirring intensity of the rapid mixing zone in the flocculation reaction tank, the stirring speed increases by 25%-30%; When increasing the dosage of flocculant, the dosage is increased from Adjust to ,in is the current flocculant dosage, is the adjusted flocculant dosage, and Satisfies the formula: ,in is the adjustment coefficient, when hour, Take 0.1-0.2; when hour, Take 0.2-0.3; when hour, Take 0.3-0.4; when hour, Take 0.5-0.6; among them, , , ; When reducing the stirring intensity in the slow flocculation zone, the stirring speed is reduced by 20%-30%; When reducing the flow rate of seawater entering the flocculation sedimentation tank, reduce the flow rate to 60%-70% of the original flow rate; When the residence time of seawater in the flocculation reaction tank is extended, the inlet flow rate is reduced by 20%-30%; When opening the mud discharge device at the bottom of the flocculation sedimentation tank, increase the speed of the mud discharge pump by 50% and increase the operating frequency of the scraper motor at the same time.

4. The seawater desalination impurity pretreatment process according to claim 1, characterized in that: The temperature range that is conducive to the flocculation reaction is 27-32 degrees Celsius; the ultrafiltration uses a hollow fiber ultrafiltration membrane with a membrane pore size of 0.01-0.1 μm and an operating pressure of 0.1-0.3 MPa. During the ultrafiltration process, air-water backwashing is performed every 30-60 minutes, and the backwashing time is 3-5 minutes; when the membrane flux drops to 70%-80% of the initial value, the chemical cleaning program is started, and a citric acid solution with a mass fraction of 2%-3% or a sodium hydroxide solution with a mass fraction of 0.5%-1% is used for circulating cleaning, and the cleaning time is 60-90 minutes.

5. A seawater desalination impurity pretreatment system, which performs the seawater desalination impurity pretreatment process according to claim 1, characterized in that: It includes a coarse filtration module, a flocculation sedimentation module, a filter module, an ultrafiltration module, a control system module and a pipeline and valve system module; the flocculation sedimentation module includes a seawater temperature detection unit, a heating unit, a mixing tank unit, a flocculation reaction tank unit, and a flocculation sedimentation tank unit, the seawater temperature detection unit includes an inlet temperature detection sensor and an outlet temperature detection sensor, the heating unit is used to heat the seawater discharged from the coarse filtration module, the inlet temperature detection sensor is used to detect the temperature of the seawater discharged from the coarse filtration module, and the outlet temperature detection sensor is used to detect the temperature of the seawater after heating by the heating unit; the mixing tank unit includes a mixing tank and a flocculant addition system, the mixing tank is provided with a stirring device, the flocculation reaction tank is provided with a stirring device, and the flocculation reaction tank is provided with a stirring device. The agent addition system is used to add flocculant to the mixing tank; the flocculation reaction tank unit includes a rapid mixing zone and a slow flocculation zone arranged in sequence along the direction of coastal water flow, a guide plate is provided between the rapid mixing zone and the slow flocculation zone, and a stirring device is provided in each of the rapid mixing zone and the slow flocculation zone; the flocculation sedimentation tank unit includes a flocculation sedimentation tank, a plurality of concentration sensors are provided in the flocculation sedimentation tank, and each concentration sensor is respectively provided at a different depth in the flocculation sedimentation tank; the control system module is used to be electrically connected to the coarse filtration module, the flocculation sedimentation module, the filter module, the ultrafiltration module and the pipeline and valve system module, to collect data transmitted from each module in real time, and to perform corresponding regulation based on a preset algorithm and threshold judgment; The filter module includes a multi-media filter and a security filter. The multi-media filter includes a tank body, a lifting assembly and a water pump. The tank body is provided with a sewage suction pipe and an ultrasonic generator, and the water suction end of the water pump is connected to the sewage suction pipe; the lifting assembly is installed on the tank body, and the output end of the lifting assembly is inserted into the tank body. The sewage suction pipe is plugged and connected with a directional suction pipe, and the directional suction pipe is connected to the output end of the lifting assembly, and the lifting assembly is used to drive the directional suction pipe to move up and down; a multi-media filter element is provided in the tank body, and there are multiple multi-media filter elements, which are located in the tank body. Guide plates are provided at the top and bottom ends of the multi-media filter element and between two adjacent filter media. Guide holes are evenly opened on the guide plates. The aperture size of the guide holes on each guide plate is different, and the aperture size of the guide holes of multiple guide plates gradually decreases from top to bottom.

6. The seawater desalination impurity pretreatment system according to claim 5, characterized in that: The concentration sensors in the flocculation sedimentation tank include an upper water concentration sensor, a middle water concentration sensor and a lower water concentration sensor. The upper water concentration sensor is set at 0.5-1 meters below the water surface, and the middle water concentration sensor is set at a distance of 1 meter from the bottom of the tank. - within the range of is the depth of the thickening tank, and ≥3 meters, the lower water concentration sensor is set within the range of 0.3-0.8 meters from the bottom of the pool.

7. The seawater desalination impurity pretreatment system according to claim 6, characterized in that: The pipeline and valve system module is used to connect the coarse filtration module, the flocculation and sedimentation module, the filter module, and the ultrafiltration module to form a complete seawater transportation path; the pipeline and valve system module is provided with an electrically controlled regulating valve on the connecting pipeline between the coarse filtration module and the flocculation and sedimentation module, which is used to regulate the flow rate of seawater entering the flocculation and sedimentation module under the control of the control system module; the electrically controlled regulating valve is provided on the pipeline between the flocculation reaction tank unit and the flocculation sedimentation tank unit, which is used to regulate the flow rate of seawater entering the flocculation sedimentation tank under the control of the control system module.

Images