A geothermal water source non-chemical scale inhibition and removal system

Abstract

The application discloses a geothermal water source non-chemical scale inhibition and removal system and belongs to the technical field of geothermal energy utilization and water treatment. The system comprises, in sequence along the flow direction of geothermal water, a temperature control induced crystallization unit, a flow state shearing scale inhibition unit, a cyclone separation scale removal unit and a bypass online cleaning unit. The temperature control induced crystallization unit makes calcium and magnesium ions preferentially pre-crystallize on the surface of suspended seed crystals through gradient temperature spoiler and suspended seed crystal layer; the flow state shearing scale inhibition unit generates high wall shear force by using a spiral turbulent flow generator and an elastic polymer lining to inhibit crystal adhesion; the cyclone separation scale removal unit centrifugally separates and discharges suspended scale crystals, and low supersaturation geothermal water is obtained and sent into a heat exchanger; and the bypass online cleaning unit removes trace adhered scale through pressure alternating cavitation online cleaning. The application realizes efficient scale inhibition and continuous scale removal through integrated and synergistic control of pre-crystallization, wall inhibition, suspended removal and online cleaning without chemical agents, and is environment-friendly, highly adaptable and low in operation and maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of geothermal energy utilization and water treatment technology, specifically to a non-chemical scale inhibition and removal system for geothermal water sources. Background Technology

[0002] Geothermal resources, as a clean and renewable green energy source, are increasingly widely used in heating, power generation, and industrial and agricultural applications. However, geothermal water typically has high mineralization, total hardness, and alkalinity, and contains large amounts of calcium, magnesium, silicon, iron, and other ions. During the extraction, transportation, and heat exchange of geothermal water, dissolved ions easily precipitate and form dense scale layers due to changes in temperature, pressure, and pH. Common scale types include calcium carbonate, calcium sulfate, silicates, and iron scale.

[0003] Scaling problems pose a serious threat to geothermal energy systems, mainly in the following aspects:

[0004] (1) The heat exchange efficiency drops significantly: the thermal conductivity of the scale layer is much lower than that of the metal pipe wall (the thermal conductivity of calcium carbonate scale is about 2.2 W / (m·K), while that of steel is about 45 W / (m·K)). A scale layer of only 1 mm thick can cause the heat exchange efficiency to drop by 10%~30%. As the operating time increases, the energy consumption increases sharply.

[0005] (2) Increased flow resistance and equipment blockage: Scale gradually deposits on the inner wall of pipes, valves, pumps and heat exchange plates, resulting in a reduction of flow cross-section and an increase in flow resistance. In severe cases, it can cause pipeline blockage and prevent the system from operating normally.

[0006] (3) Accelerated equipment corrosion: Oxygen concentration cells or acidic microenvironments often form under the scale layer, leading to local corrosion under the scale, and even perforation and leakage, which shortens the service life of the equipment.

[0007] (4) High operation and maintenance costs: Traditional descaling methods require shutdown for mechanical cleaning or chemical acid washing, which not only affects the continuity of heating or power generation, but also causes multiple costs such as labor, equipment and wastewater treatment.

[0008] To address the scaling problem in geothermal water, existing technologies are mainly divided into two categories: chemical methods and physical methods.

[0009] Chemical scale inhibition and removal technology is currently the most widely used method, mainly involving the addition of scale inhibitors, dispersants, chelating agents, or periodic acid washing. However, chemical methods have significant limitations in geothermal utilization: First, geothermal water usually needs to be reinjected underground to maintain thermal storage pressure and protect the environment, and the addition of chemical agents may pollute groundwater sources and geological structures; second, the effectiveness of scale inhibitors is greatly affected by water quality, temperature, and flow rate, and their effect is unstable for high-temperature, high-hardness geothermal water; third, the waste liquid generated by chemical cleaning needs to be treated to meet standards before discharge, increasing the environmental burden and operating costs.

[0010] Physical scale inhibition and removal technologies have seen some development in recent years, mainly including:

[0011] (1) Electromagnetic or permanent magnet treatment: The magnetic field changes the ion hydration state or affects the crystal nucleus formation process, but its effect is highly controversial and is greatly affected by parameters such as water quality, flow rate, and magnetic field strength. It has poor stability and is basically ineffective for hard scale that has already formed.

[0012] (2) Ultrasonic or pulse treatment: High-frequency vibration is used to break or peel off the scale layer on the wall, but the equipment has high energy consumption and limited range of action. It is not ideal for long-distance pipelines or complex heat exchanger structures.

[0013] (3) Crystallization bed or fluidized bed technology: Solid particles are filled into the reactor to induce calcium and magnesium ions to crystallize preferentially on their surface, thereby reducing scaling on the wall. This type of method does not use chemical agents and has certain advantages, but there are still prominent problems: First, after the particle surface is saturated with crystals, it needs to be replaced or regenerated frequently; second, secondary scaling may still occur inside the reactor and in subsequent pipelines; third, there is a lack of effective means to separate the already formed suspended crystals, which leads to continued scaling after the geothermal water with high supersaturation enters the heat exchanger.

[0014] (4) Spiral flow or turbulence enhancement technology: By changing the flow channel structure, the degree of fluid turbulence is enhanced, the wall shear force is increased, and the scale adhesion is delayed. This technology can be used as an auxiliary means, but when used alone, the scale inhibition effect is limited and it cannot fundamentally reduce the saturation of scale-forming ions in the water.

[0015] In summary, existing non-chemical scale inhibition and removal technologies mostly employ single physical methods, which have limitations such as either only inhibiting or only removing scale without inhibiting it, and lack integrated and coordinated control over the entire process of pre-crystallization, wall adhesion inhibition, and suspended scale removal. In particular, the core problem of scale precipitation in geothermal water systems lies in the local supersaturation and crystallization of scale-forming ions near the heat exchange wall. Existing technologies have failed to effectively address the two key aspects of transferring scale formation from the heat exchange wall to the fluid bulk and continuously removing scale crystals from the system.

[0016] Therefore, developing a geothermal water source scale inhibition and removal system that does not require the addition of chemical agents, can simultaneously achieve efficient scale inhibition and continuous scale removal, is adaptable to different geothermal water qualities, and has online self-maintenance capabilities is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0017] This invention provides a non-chemical scale inhibition and removal system for geothermal water sources. Through integrated and coordinated control, it achieves efficient scale inhibition and continuous scale removal in geothermal water systems. It has the advantages of being environmentally friendly, highly adaptable, and having low operation and maintenance costs, and is suitable for geothermal heating, power generation, and industrial and agricultural applications.

[0018] To achieve the above objectives, the present invention provides the following technical solution: a non-chemical scale inhibition and removal system for geothermal water sources, comprising, in sequence along the geothermal water flow direction: a temperature-controlled induced crystallization unit, which is internally equipped with a gradient cooling baffle assembly and a suspended induced crystal seed layer, used to induce a controlled pre-crystallization reaction in the geothermal water before it enters the heat exchanger, preferentially precipitating calcium and magnesium ions on the surface of the suspended crystal seed layer; and a flow-mode shear scale inhibition unit, whose inlet is connected to the outlet of the temperature-controlled induced crystallization unit, and internally equipped with a spiral turbulence generator, with its inner wall surface covered with an elastic polymer liner to generate Taylor vortices. The system utilizes wall shear force to inhibit crystal adhesion to the wall surface and maintain scale crystal suspension. A cyclone separation descaling unit, with its inlet connected to the outlet of the fluidized shear scale inhibition unit, centrifugally separates suspended crystalline particles from the geothermal water and discharges them from the system, obtaining clean geothermal water with low supersaturation for delivery to the heat exchanger. A bypass online cleaning unit, with its inlet connected to the heavy phase outlet of the cyclone separation descaling unit, returns its outlet via a cleaning pipeline to the inlet of the fluidized shear scale inhibition unit or the inlet of the temperature-controlled induced crystallization unit. It is equipped with an internal pressure alternating cavitation generator for online removal of trace amounts of scale adhering to the system.

[0019] Preferably, the gradient cooling baffle assembly in the temperature-controlled induced crystallization unit is arranged in multiple stages along the water flow direction, with each stage having a different opening ratio and tilt angle, and the temperature drop rate of the geothermal water flowing through it is controlled within the range of 0.3~2.0℃ / m.

[0020] Preferably, the suspended seed layer is composed of inert solid particles with a particle size of 0.2 to 1.0 mm, wherein the solid particles are selected from one or more of natural calcite, zeolite, quartz sand or artificial ceramic particles, and the suspension density is 30 to 300 g / L.

[0021] Preferably, in the suspended seed layer, the solid particles have a particle size of 0.3~0.8 mm, a suspension density of 80~150 g / L, and a temperature drop rate of 0.5~1.5℃ / m.

[0022] Preferably, the surface of the elastic polymer liner has a micron-level groove structure with a groove depth of 20~200 μm and a spacing of 50~500 μm; the material of the elastic polymer liner is polyurethane or fluororubber.

[0023] Preferably, the Reynolds number of the geothermal water in the fluidized shear scale inhibition unit is controlled within the range of 5000 to 50000, and the wall shear stress is ≥5 Pa.

[0024] Preferably, the cyclone separation and descaling unit is a hydrocyclone, and its separation particle size d50 is controlled within the range of 5~50 μm.

[0025] Preferably, the pressure alternating cavitation generator in the bypass online cleaning unit operates at a frequency of 10~100kHz and has an alternating operating pressure amplitude of 0.2~1.0 MPa; when the system detects that the differential pressure rises above the set threshold, the bypass cleaning mode is automatically activated.

[0026] Preferably, it also includes an automatic control unit, which is electrically connected to the temperature sensor of the temperature-controlled induced crystallization unit, the pressure sensor of the fluid shear scale inhibition unit, the differential pressure sensor of the cyclone separation descaling unit, and the electric valve of the bypass online cleaning unit, respectively, and is used to automatically adjust the gradient cooling amplitude, bypass cleaning start / stop, and cleaning cycle according to the real-time detection signal.

[0027] The beneficial effects of this invention are as follows: The non-chemical scale inhibition and removal system for geothermal water sources provided by this invention has the following beneficial effects:

[0028] (1) Integrated and Synergistic Scale Inhibition and Removal: This invention is the first to organically connect four functional units—temperature-controlled induced pre-crystallization, fluid shear wall inhibition, cyclone separation and suspension removal, and bypass cavitation online cleaning—to form a closed-loop control chain encompassing pre-crystallization, wall adhesion inhibition, suspended scale removal, and online removal of trace scale layers. Compared with existing single physical methods that only inhibit or remove scale, this invention fundamentally solves the core contradiction of geothermal water scaling, shifting the scaling location from the heat exchange wall to the fluid body and continuously discharging scale crystals from the system, achieving continuous and efficient scale inhibition and removal without shutdown.

[0029] (2) Completely non-chemical and environmentally friendly: The entire system does not add any scale inhibitors, dispersants, chelating agents or pickling solutions, avoiding chemical pollution to groundwater sources and geological structures, and is especially suitable for environmentally strict areas that require 100% geothermal water reinjection. The scale crystals discharged by the system are dry or semi-dry solids that can be centrally disposed of or utilized as resources, with no wastewater discharge, significantly reducing the environmental burden.

[0030] (3) High adaptability and high scale inhibition efficiency: Through the multi-stage gradient cooling baffle and adjustable suspended seed crystal layer of the temperature-controlled induced crystallization unit, the pre-crystallization intensity can be flexibly adjusted according to different geothermal water quality; the elastic polymer liner of the flow-state shear scale inhibition unit combined with the spiral turbulence generator can maintain high shear stress on the wall surface within a wide Reynolds number range, effectively inhibiting crystal adhesion; the cyclone separation descaling unit can select different separation particle sizes according to the width of the heat exchanger channel to ensure that the geothermal water fed into the heat exchanger has low supersaturation. According to the test, the calcium carbonate pre-crystallization rate reaches 40%~65%, the suspended particle removal rate is ≥85%, the scale layer thickness inside the heat exchanger can be controlled below 0.1 mm, and the heat exchange efficiency decay is less than 5%.

[0031] (4) Possesses online self-maintenance capability, significantly reducing operation and maintenance costs: The bypass online cleaning unit, in conjunction with the automatic control unit, automatically activates the pressure alternating cavitation cleaning mode when the system pressure differential increases. It can remove trace amounts of deposited scale that may exist in the system without stopping the machine for disassembly, avoiding the downtime, manual scale removal, and waste liquid treatment costs required by traditional mechanical cleaning or chemical acid washing. The system can achieve long-term continuous and stable operation, significantly extending the equipment maintenance cycle and service life.

[0032] (5) Energy saving and consumption reduction, improving the economic efficiency of geothermal utilization: Since the heat exchanger always maintains high heat transfer efficiency, the energy consumption of geothermal heating or power generation system is significantly reduced; at the same time, the system itself only consumes a small amount of pumping power and ultrasonic / cavitation energy, and the energy consumption per unit of treated water is less than 0.2 kWh / m³. 3 It exhibits outstanding energy-saving benefits. Comprehensive calculations show that this invention can reduce the overall operating cost of geothermal utilization systems by 30% to 50%. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0035] In the diagram: 1. Temperature-controlled induced crystallization unit; 2. Gradient cooling baffle plate; 3. Suspended induced crystal seed layer; 4. Flow-based shear scale inhibition unit; 5. Elastic polymer liner; 6. Spiral turbulence generator; 7. Swirl separation descaling unit; 8. Heat exchanger; 9. Bypass online cleaning unit; 10. Temperature sensor; 11. Pressure sensor; 12. Differential pressure sensor; 13. Electric valve. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] according to Figure 1 As shown, this embodiment provides a non-chemical scale inhibition and removal system for geothermal water sources, which includes, in sequence along the geothermal water flow direction: a temperature-controlled induced crystallization unit 1, a flow-shear scale inhibition unit 4, a cyclone separation scale removal unit 7, a bypass online cleaning unit 9, and an automatic control unit. The geothermal water treatment units are connected in series via corrosion-resistant pipes.

[0039] The temperature-controlled induced crystallization unit 1 is a vertical cylindrical reactor, which contains a gradient cooling baffle plate assembly 2 and a suspended induced crystal seed layer 3. Geothermal water enters from the bottom, is treated, and flows out from the top.

[0040] The gradient cooling baffle assembly 2 is arranged in multiple stages along the water flow direction. The first stage baffle has an opening ratio of 40% and an inclination angle of 15°; the second stage baffle has an opening ratio of 30% and an inclination angle of 30°; and the third stage baffle has an opening ratio of 20% and an inclination angle of 45°. Through this progressively increasing baffle intensity and progressively decreasing flow cross-section, the temperature drop rate of the geothermal water is controlled at 0.5℃ / m. In actual operation, the inlet geothermal water temperature is 75℃, and the outlet temperature after passing through the temperature-controlled induced crystallization unit 1 is 65℃. The effective height of the unit is 20m, and the average temperature drop rate is 0.5℃ / m. The suspended induced crystal seed layer 3 is composed of natural calcite particles with a particle size of 0.3~0.8mm and a suspension density of 120g / L. Under the action of the rising water flow caused by the baffle, the calcite particles are in a fluidized suspended state, forming a huge induced crystallization specific surface area. Calcium and magnesium ions in geothermal water preferentially precipitate on the surface of these suspended seed crystals, rather than forming scale on the metal walls of subsequent equipment. Tests showed that the pre-crystallization rate of calcium carbonate in this unit can reach 40%–60%.

[0041] The inlet of the fluidized shear scale inhibition unit 4 is connected to the outlet of the temperature-controlled induced crystallization unit 1. Its main body is a horizontally positioned circular tube, inside which is a spiral turbulence generator 6, such as a spiral twisted blade or spiral guide vane, and the inner wall surface is covered with an elastic polymer liner 5. The elastic polymer liner 5 is made of polyurethane, and its surface is laser-engraved to form a micron-level groove structure: the groove depth is 100μm, the spacing is 200μm, and the groove direction is arranged in a small-angle spiral along the fluid flow direction. This structure reduces the actual contact area between scale crystals and the wall surface, while facilitating the detachment of bubbles and microcrystals. The spiral turbulence generator 6 induces strong tangential flow in the geothermal water, forming Taylor vortices. The Reynolds number of the geothermal water in this unit is controlled within the range of 15000~25000, and the wall shear stress is ≥8Pa. Under these high shear conditions, suspended scale crystals are difficult to deposit on the wall surface. Meanwhile, the tiny crystals that have already adhered to the surface of the elastic liner are peeled off by the combined action of shear force and elastic deformation of the liner and return to the bulk fluid, thus keeping the wall surface clean.

[0042] The hydrocyclone separation and descaling unit 7 is a single-stage hydrocyclone, with its inlet connected to the outlet of the flow-shear scale inhibition unit 4. The separation particle size d50 of the hydrocyclone is controlled at 20μm. Geothermal water enters the hydrocyclone tangentially. In the centrifugal force field, denser crystalline particles are thrown against the wall and move downwards, exiting from the heavy phase outlet; while the clarified, low-supersaturated geothermal water flows out from the light phase outlet and is sent to the subsequent heat exchanger 8 for thermal energy utilization. Actual testing shows that after hydrocyclone separation, the removal rate of suspended particles in the geothermal water is ≥85%, and the calcium carbonate saturation index drops from 1.5 to below 0.8, effectively preventing a large amount of secondary scaling in the heat exchanger 8.

[0043] The inlet of the bypass online cleaning unit 9 is connected to the heavy phase outlet of the cyclone separation descaling unit 7, and the outlet returns to the inlet of the fluid shear scale inhibition unit 4 or the inlet of the temperature-controlled induced crystallization unit 1 via a cleaning pipeline. A pressure alternating cavitation generator is installed on this bypass pipeline. The pressure alternating cavitation generator adopts a combination structure of an ultrasonic transducer and a pulsating pressure valve, with a working frequency of 40kHz and a working pressure alternating amplitude of 0.5MPa, periodically and rapidly changing between 0.2 and 0.7MPa. When the system's automatic control unit detects that the pressure difference of the fluid shear scale inhibition unit 4 or the temperature-controlled induced crystallization unit 1 exceeds a set threshold, such as 0.05MPa, the bypass cleaning mode is automatically activated. At this time, the circulating water containing a small amount of tiny scale crystals discharged from the underflow of the cyclone separator enters the bypass, generating a strong cavitation bubble collapse effect in the pressure alternating cavitation generator, producing local micro-jet and shock waves, which peel off and break up any trace amounts of scale that may exist in the system, and then re-enter the main circulation system, where it is removed again by the cyclone separation unit.

[0044] The automatic control unit is electrically connected to the temperature sensor 10 of the temperature-controlled induced crystallization unit 1, the pressure sensor 11 of the fluid shear scale inhibition unit 4, the differential pressure sensor 12 of the cyclone separation descaling unit 7, the electric valve 13 of the bypass online cleaning unit 9, and the flow regulating valves of each unit. The automatic control unit uses a PLC controller to automatically adjust the gradient cooling amplitude, bypass cleaning start / stop, and cleaning cycle based on real-time detection signals. For example, when the hardness of the local hot water suddenly increases, the controller will automatically reduce the outlet temperature setpoint of the temperature-controlled induced crystallization unit 1 and increase the bypass cleaning frequency.

[0045] Example 2:

[0046] This embodiment is basically the same as Embodiment 1, except that the parameters of the temperature-controlled induced crystallization unit 1 are different. In this embodiment, the geothermal water inlet temperature is 85℃, the outlet temperature is 55℃, the effective height of the temperature-controlled induced crystallization unit 1 is 20m, and the temperature drop rate is 1.5℃ / m. The gradient cooling baffle plate 2 assembly is arranged in four stages, with opening ratios of 45%, 35%, 25%, and 15% respectively, and inclination angles of 10°, 20°, 35°, and 50° respectively. The suspended induced crystal seed layer 3 is composed of zeolite and quartz sand mixed particles with a particle size of 0.5~1.0mm, with a mass ratio of 1:1 and a suspension density of 200g / L. This configuration is suitable for geothermal water with high hardness and high mineralization, such as total hardness >500mg / L CaCO3, which can further improve the pre-crystallization efficiency, that is, the calcium carbonate pre-crystallization rate can reach more than 65%, but the system flow resistance increases slightly.

[0047] Example 3:

[0048] This embodiment is basically the same as Embodiment 1, except that the materials and structures of the fluidized shear scale inhibition unit 4 and the elastic polymer liner 5 are different. The elastic polymer liner 5 is made of fluororubber, which has better high-temperature resistance and corrosion resistance. Its surface micron-level groove structure is as follows: groove depth 50μm, spacing 100μm, and groove direction is circumferential annular groove. The Reynolds number is controlled in the range of 5000~10000, and the wall shear stress is ≥5Pa. This configuration is suitable for geothermal water with higher temperature or strong sulfur and chlorine content, and can operate stably for a long time without lining aging or corrosion.

[0049] Example 4: This example is basically the same as Example 1, except for the control of the separation particle size of the hydrocyclone separation descaling unit 7. In this example, the separation particle size d50 of the hydrocyclone is 10μm, which is suitable for occasions with extremely high requirements for effluent water quality and very narrow heat exchanger 8 channels. Although the pressure drop is slightly increased, the suspended scale removal rate can be further improved to over 95%.

[0050] The system described in Embodiment 1 of this invention was applied to a real geothermal heating project. The geothermal water quality parameters were: total hardness 420 mg / L, total alkalinity 280 mg / L, water temperature 75℃, and flow rate 50 m³ / L. 3 The system ran continuously for 180 days. The test results are as follows:

[0051] Scale inhibition effect: The average scale thickness on the inner wall of heat exchanger 8 is <0.1mm, while under the same water quality conditions without any treatment, the scale thickness reaches 1.8~2.5mm in the same operating cycle.

[0052] Heat exchange efficiency: The overall heat transfer coefficient of heat exchanger 8 decreased by only about 3%, while the control group decreased by 28%.

[0053] Descaling capacity: The cyclone separation descaling unit 7 discharges approximately 3.5~5.2 kg of wet scale per day, which, according to XRD analysis, is mainly calcium carbonate and a small amount of silicate.

[0054] System differential pressure: The total system differential pressure increased from the initial 0.12MPa to 0.15MPa, which is far below the alarm threshold, so there is no need to shut down the system for cleaning.

[0055] Non-chemical characteristics: No chemical scale inhibitors or acid washing solutions were added throughout the process, the quality of the reinjected water was basically the same as that of the original hot water, and no external pollutants were introduced.

[0056] Comparative experiment:

[0057] Set up three comparison systems:

[0058] Comparative Example 1: Only temperature-controlled induced crystallization unit 1 is used, i.e., no flow shearing and cyclone separation;

[0059] Comparative Example 2: Hydrocyclone only, i.e. no pre-crystallization and shear scale inhibition;

[0060] Comparative Example 3: Commercially available permanent magnet scale inhibitor.

[0061] After 30 days of operation, Comparative Example 1 showed a significant scale layer of approximately 0.6 mm inside heat exchanger 8, with a large amount of suspended crystals deposited within it. Comparative Example 2, lacking pre-induced crystallization, allowed fine scale crystals to continue growing within heat exchanger 8, resulting in significant scale formation of approximately 0.8 mm. Comparative Example 3 was essentially ineffective, with a scale layer thickness reaching 1.5 mm. These comparisons demonstrate that the present invention, through integrated and synergistic control of pre-crystallization, wall adhesion inhibition, and suspended scale crystal removal, is significantly superior to single physical treatment technologies.

[0062] As other alternative implementations, those skilled in the art should understand that the above embodiments are only some preferred embodiments of the present invention and are not exhaustive. Under the premise of meeting actual engineering needs, the specific structure, size, material, and operating parameters of each unit can be reasonably adjusted according to the geothermal water quality, flow rate, temperature, and heat exchange equipment requirements. For example, the cooling method of the temperature-controlled induced crystallization unit 1 can also be indirectly cooled by an external cooling water jacket or plate heat exchanger 8, rather than relying entirely on natural heat dissipation from the baffle plate. The spiral turbulence generator 6 in the flow-shear scale inhibition unit 4 can be designed as a detachable or variable pitch structure to adapt to different flow velocities and scale types. The cyclone separation descaling unit 7 can adopt a multi-stage series or parallel hydrocyclone group to further improve treatment accuracy or throughput. The pressure alternating cavitation generator of the bypass online cleaning unit 9 can also adopt a combination of a high-frequency pulse valve and a venturi tube, eliminating the need for an ultrasonic transducer. All the above modifications do not depart from the core concept of the present invention and should be considered to fall within the scope of protection claimed by the present invention.

[0063] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A non-chemical scale inhibition and removal system for geothermal water sources, characterized in that, Along the direction of geothermal water flow, the following are included in sequence: The temperature-controlled induced crystallization unit (1) is equipped with a gradient cooling baffle plate (2) assembly and a suspended induced crystal seed layer (3) to enable the geothermal water to undergo a controlled pre-crystallization reaction before entering the heat exchanger (8), so that calcium and magnesium ions are preferentially precipitated on the surface of the suspended crystal seed. The flow-state shear scale inhibition unit (4) has its inlet connected to the outlet of the temperature-controlled induced crystallization unit (1), and is equipped with a spiral turbulence generator (6) inside. The inner wall surface is covered with an elastic polymer liner (5) to generate Taylor eddies and wall shear forces, inhibit crystals from adhering to the wall surface and maintain scale crystal suspension. The cyclone separation descaling unit (7) has its inlet connected to the outlet of the flow shear scale inhibition unit (4), which is used to centrifuge the suspended crystal particles from the geothermal water and discharge them from the system, so as to obtain clean geothermal water with low supersaturation and send it into the heat exchanger (8). The bypass online cleaning unit (9) has its inlet connected to the heavy phase outlet of the cyclone separation descaling unit (7), and its outlet returns to the inlet of the fluid shear scale inhibition unit (4) or the inlet of the temperature-controlled induced crystallization unit (1) via the cleaning pipeline. It is equipped with a pressure alternating cavitation generator for online removal of trace amounts of scale attached to the system.

2. The geothermal water source non-chemical scale inhibition and removal system according to claim 1, characterized in that, The gradient cooling baffle (2) component in the temperature-controlled induced crystallization unit (1) is arranged in multiple stages along the water flow direction. Each stage of the baffle has a different opening ratio and tilt angle. The temperature drop rate of the geothermal water flowing through is controlled within the range of 0.3~2.0℃ / m.

3. The geothermal water source non-chemical scale inhibition and removal system according to claim 1, characterized in that, The suspended seed layer (3) is composed of inert solid particles with a particle size of 0.2~1.0 mm. The solid particles are selected from one or more of natural calcite, zeolite, quartz sand or artificial ceramic particles, and their suspension density is 30~300 g / L.

4. The geothermal water source non-chemical scale inhibition and removal system according to claim 3, characterized in that, In the suspended seed layer (3), the particle size of the solid particles is 0.3~0.8 mm, the suspension density is 80~150 g / L, and the temperature drop rate is 0.5~1.5℃ / m.

5. The geothermal water source non-chemical scale inhibition and removal system according to claim 1, characterized in that, The surface of the elastic polymer liner (5) has a micron-level groove structure with a groove depth of 20~200 μm and a spacing of 50~500 μm; the material of the elastic polymer liner (5) is polyurethane or fluororubber.

6. The geothermal water source non-chemical scale inhibition and removal system according to claim 1, characterized in that, The Reynolds number of the geothermal water in the fluidized shear scale inhibition unit (4) is controlled within the range of 5000~50000, and the wall shear stress is ≥5 Pa.

7. The geothermal water source non-chemical scale inhibition and removal system according to claim 1, characterized in that, The hydrocyclone separation and descaling unit (7) is a hydrocyclone, and its separation particle size d50 is controlled within the range of 5~50 μm.

8. The geothermal water source non-chemical scale inhibition and removal system according to claim 1, characterized in that, The working frequency of the pressure alternating cavitation generator in the bypass online cleaning unit (9) is 10~100 kHz, and the working pressure alternating amplitude is 0.2~1.0 MPa; when the system detects that the pressure difference increases beyond the set threshold, the bypass cleaning mode is automatically activated.

9. The geothermal water source non-chemical scale inhibition and removal system according to claim 1, characterized in that, It also includes an automatic control unit, which is electrically connected to the temperature sensor (10) of the temperature-controlled induced crystallization unit (1), the pressure sensor (11) of the fluid shear scale inhibition unit (4), the differential pressure sensor (12) of the cyclone separation descaling unit (7), and the electric valve (13) of the bypass online cleaning unit (9), and is used to automatically adjust the gradient cooling amplitude, bypass cleaning start and stop and cleaning cycle according to the real-time detection signal.

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