Low-temperature evaporation and concentration recycling system and method for medium-high temperature geothermal thermal spring water

Abstract

The invention provides a low-temperature evaporation and concentration recycling system for medium-high-temperature geothermal thermal spring water, which comprises a raw heat energy adaptation and raw water conveying unit, a pure physical pretreatment unit, a low-temperature high-power concentration unit, a solid-liquid concentrated liquor treatment and mineral recovery unit, a condensate water full-recycling unit and an intelligent monitoring unit, the invention further provides a medium-high temperature geothermal thermal spring water low-temperature evaporation and concentration recycling method adopting the medium-high temperature geothermal thermal spring water low-temperature evaporation and concentration recycling system. According to the invention, the technical problems of primary heat energy waste, high-hardness scaling and chemical pollution of medium-high temperature geothermal hot spring water, health component attenuation, high energy consumption of tail end byproduct treatment and single resource utilization of geothermal hot spring water in the existing geothermal hot spring water concentration recycling technology are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of medium- and high-temperature geothermal hot spring water treatment and high-value utilization technology, specifically to a low-temperature evaporation and concentration system and method for the resource utilization of medium- and high-temperature geothermal hot spring water. Background Technology

[0002] China boasts abundant geothermal hot spring resources, with medium-to-high temperature geothermal hot spring water (50-70℃) accounting for over 40%. This water generally has high hardness (mostly ≥300mg / L) and is rich in trace minerals with high health and wellness value, such as metasilicic acid, lithium, and strontium. Currently, this geothermal hot spring water is mainly used for direct consumption scenarios such as bathing and showering, and is mostly discharged directly after use. Resource utilization is less than 10%, and its high-value potential has not been fully explored. The concentrated high-value utilization of geothermal hot spring water has become a new opportunity for the industry's transformation and development.

[0003] For the resource utilization of geothermal hot spring water, existing technologies are mainly divided into two categories: membrane separation concentration and evaporation concentration. Among them, existing membrane separation concentration (such as reverse osmosis) cannot directly treat medium- and high-temperature geothermal hot spring water above 50°C. It is necessary to equip a pre-cooling system for circulating raw water to cool the hot spring water to below 40°C. This not only causes water resource evaporation loss (≥5%) and the risk of secondary pollution, but also increases the investment and energy consumption of the cooling system, completely wasting the free original heat energy of medium- and high-temperature geothermal hot spring water above 50°C. Furthermore, it has low tolerance to characteristic pollutants such as high hardness calcium and magnesium ions and colloids in geothermal hot spring water, the membrane replacement cycle is only 6 to 12 months, the operation and maintenance cost is high, and the single-stage membrane concentration ratio is difficult to exceed 10 times. More importantly, in their practice of treating geothermal hot spring water using membrane separation concentration technology, the inventors of this application discovered that when the concentration ratio is increased to more than 5 times, the retention rate of core health-promoting elements such as metasilicic acid in the geothermal hot spring water concentrate drops sharply (e.g., the metasilicic acid retention rate is ≤85% when concentrated 8 times). Analysis suggests that this phenomenon is caused by a combination of factors, including the reverse osmosis membrane's retention characteristics (poor selective retention of soluble silica), concentration polarization effect (polymerization of silica at excessively high concentration on the membrane surface), and membrane surface reaction (adsorption of silica onto the membrane material). This results in a decrease in the content of elements such as metasilicic acid, severely weakening the core health-promoting value of the geothermal hot spring concentrate. This is the core bottleneck that existing membrane separation concentration technology cannot meet for the high-value concentration and utilization of geothermal hot spring water.

[0004] Most evaporation and concentration processes employ traditional multi-effect evaporation technology used in wastewater treatment. To improve evaporation capacity and energy efficiency, the system operating temperature is typically ≥80℃, which can easily lead to the decomposition of heat-sensitive health-promoting components (such as metasilicic acid) in geothermal hot spring water, resulting in a retention rate of ≤80% for these components. Simultaneously, the high hardness of geothermal hot spring water (≥300mg / L), coupled with the high temperature, exacerbates scaling during evaporation. Calcium and magnesium salts readily form a dense scale layer on the heat exchanger tube walls. The equipment's continuous operating cycle is only 7–15 days, requiring frequent cleaning, which is insufficient to meet the concentration requirements of high-hardness geothermal hot spring water. Furthermore, traditional multi-effect evaporation typically consumes ≥40kWh per ton of water, resulting in poor economic efficiency. It also struggles to utilize the inherent 50–70℃ temperature of the geothermal hot spring water, necessitating additional heating and resulting in double energy waste and insufficient thermal energy utilization. Furthermore, traditional evaporation processes rely on the addition of chemical scale inhibitors (such as phosphates and polycarboxylic acids), which can damage the naturalness and health-preserving safety of geothermal hot spring water, introducing exogenous chemical substances (scale inhibitor residue ≥0.5mg / L), which does not meet the raw material requirements for natural health-preserving products. Ordinary falling film evaporators lack active anti-scaling structures, and the flow of liquid in the boundary layer is slow (flow velocity ≤0.5m / s), which easily leads to local scaling, resulting in a decrease in heat transfer coefficient of more than 30%, further increasing energy consumption. When nanofiltration desalination technology is used for end-stage mineral recovery, it cannot adapt to the solid-liquid mixture generated by the pre-evaporation stage (membrane flux decreases by 50% when solid content ≥5%), which easily causes membrane clogging. Moreover, additional crystallization, centrifugation, and drying steps are required after separation (energy consumption for drying one ton of minerals ≥8kWh), resulting in cumulative energy consumption. It is impossible to directly produce dried mineral raw materials that can be used in hot spring mud and other scenarios with low energy consumption. At the same time, the mother liquor becomes wastewater, which does not meet the requirements for high-value utilization of resources and zero discharge.

[0005] The invention patent with authorized application number 202110825494.7, entitled "A Natural Hot Spring Water Concentration and Filling System", mainly focuses on membrane three-stage fixed pressure concentration and filling integration. It does not involve technologies such as the utilization of the original heat energy of medium and high temperature geothermal hot spring water, low temperature evaporation, pure physical scale prevention, active ingredient protection, and concentrated water drying and recovery. Furthermore, it does not adopt the coupling scheme of "front-stage scraped film evaporation concentration + terminal low temperature drying evaporation crystallization recovery of mineral by-products". It cannot solve the core pain points of high-value concentration and drying mineral recovery of high-hardness geothermal hot spring water, and does not conform to the trend of high-value resource utilization. Summary of the Invention

[0006] To address the technical problems of existing geothermal hot spring water concentration and resource utilization technologies, such as waste of primary heat energy of medium and high temperature geothermal hot spring water, high hardness scaling and chemical pollution, decay of health and health components, high energy consumption for end-of-pipe by-product treatment, and limited utilization of geothermal hot spring resources, this invention provides a low-temperature evaporation concentration and resource utilization system for medium and high temperature geothermal hot spring water.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A low-temperature evaporation and concentration resource utilization system for medium- and high-temperature geothermal hot spring water includes a primary thermal energy adaptation and raw water transportation unit, a purely physical pretreatment unit, a low-temperature high-concentration unit, a solid-liquid-concentrate treatment and mineral recovery unit, a condensate full reuse unit, and an intelligent monitoring unit; wherein...

[0009] The original thermal energy adaptation and raw water delivery unit includes a medium-high temperature geothermal hot spring raw water pipeline, an insulated raw water tank, a raw water pump, and a high temperature heat exchanger. The high temperature geothermal hot spring raw water pipeline, the insulated raw water tank, and the raw water pump are connected in sequence through pipelines. A raw water temperature sensor and a main switch valve are connected in sequence to the outlet pipeline of the raw water pump. The inlet and outlet of the high temperature heat exchanger are connected in parallel to the pipelines at the inlet and outlet of the main switch valve through pipelines. A heat exchange switch valve is connected to the inlet and outlet pipelines of the high temperature heat exchanger. The cold medium inlet of the high temperature heat exchanger is connected to the condensate output from the low temperature high concentration unit through a pipeline.

[0010] The pure physical pretreatment unit includes a high-frequency pulse physical scale inhibitor, a multi-channel cyclone separator, and a high-temperature precision filter connected in sequence through pipelines. The inlet of the high-frequency pulse physical scale inhibitor is connected to the outlet pipeline of the raw water pump.

[0011] The low-temperature high-concentration unit includes a scraped-film evaporator, an MVR steam compressor, a hot spring concentrate outlet pump, a low-concentration concentrate buffer tank, a low-concentration concentrate filling pump, a low-concentration concentrate filling pipeline, a high-concentration concentrate buffer tank, a high-concentration concentrate filling pump, and a high-concentration concentrate filling pipeline. The inlet of the scraped-film evaporator is connected to the outlet of a high-temperature precision filter via a pipeline. A feed flow control valve and a feed metasilicic acid analyzer are fixedly installed at the inlet of the scraped-film evaporator. The secondary steam outlet of the scraped-film evaporator is connected to the steam inlet of the MVR steam compressor. The steam outlet of the MVR steam compressor is connected to the steam inlet of the scraped-film evaporator and the solid-liquid concentrate treatment and mineral recovery unit. The condensate outlet of the scraped-film evaporator is connected to the cold medium inlet of a high-temperature heat exchanger via a pipeline. The scraped-film evaporator is equipped with an evaporation temperature sensor, a feed liquid viscosity sensor, a feed liquid TDS sensor, and a discharge metasilicic acid analyzer at its concentrate outlet. The concentrate outlet of the scraped-film evaporator is connected to the inlet of a hot spring concentrate outlet pump via a pipeline. The outlet of the hot spring concentrate outlet pump is connected to the inlets of a low-concentration concentrate buffer tank and a high-concentration concentrate buffer tank via pipelines. A low-concentration concentrate inlet switch valve is connected to the inlet pipeline of the low-concentration concentrate buffer tank, and a high-concentration concentrate inlet switch valve is connected to the inlet pipeline of the high-concentration concentrate buffer tank. The outlet of the low-concentration concentrate buffer tank is connected to a low-concentration concentrate filling pump and a low-concentration concentrate filling pipeline in sequence via pipelines, and the outlet of the high-concentration concentrate buffer tank is connected to a high-concentration concentrate filling pump and a high-concentration concentrate filling pipeline in sequence via pipelines.

[0012] The solid-liquid concentrate treatment and mineral recovery unit includes a solid-liquid concentrate discharge pump, a low-temperature scraped-plate drying evaporator, a mineral by-product collection box, and a mineral by-product packaging system. The inlet of the solid-liquid concentrate discharge pump is connected to the solid-liquid concentrate outlet of the scraped-plate thin-film evaporator and the multi-channel cyclone separator via a pipeline. The outlet of the solid-liquid concentrate discharge pump is connected to the pre-stage solid-liquid concentrate inlet of the low-temperature scraped-plate drying evaporator via a pipeline. The steam inlet of the low-temperature scraped-plate drying evaporator is connected to the steam outlet of the MVR steam compressor via a pipeline. The secondary steam outlet of the low-temperature scraped-plate drying evaporator is connected to the steam inlet of the MVR steam compressor. The inlet of the mineral by-product collection box is connected to the dried mineral by-product outlet of the low-temperature scraped-plate drying evaporator. The outlet of the mineral by-product collection box is connected to the mineral by-product packaging system. A moisture sensor is also installed at the dried mineral by-product outlet of the low-temperature scraped-plate drying evaporator.

[0013] The condensate recycling unit includes a condensate buffer tank, a condensate delivery pump, and a condensate recycling system. A conductivity meter is fixedly installed on the condensate buffer tank. The inlet of the condensate buffer tank is connected to the cold medium outlet of the high-temperature heat exchanger and the condensate outlet of the low-temperature scraper drying evaporator. The outlet of the condensate buffer tank is connected to the condensate delivery pump and the condensate recycling system in sequence through pipelines. The condensate recycling system is divided into a pool water replenishment branch and a landscape irrigation branch.

[0014] The intelligent monitoring unit is electrically connected to the raw water pump, scraped film evaporator, MVR steam compressor, low-temperature scraped drying evaporator, metasilicic acid analyzer, various pumps, valves and sensors.

[0015] Furthermore, the inner wall of the insulated raw water tank is provided with a polyurethane insulation layer with a thickness of ≥50mm and a heat loss of ≤1.8% / h.

[0016] Furthermore, the scraped-film evaporator includes a shell, with a water inlet and a secondary steam outlet opposite each other at the top of the shell. A film-forming heat exchange tube shell is integrally formed at the lower end of the shell, and a heating jacket is fixed to the outer wall of the film-forming heat exchange tube shell. A steam inlet is provided on the upper part of one side of the heating jacket, and a condensate outlet is provided on the lower part of the other side of the heating jacket. A concentrate outlet is provided at the lower part of the shell below the condensate outlet, and a solid-liquid concentrate outlet is provided at the bottom of the shell. A scraper drive motor electrically connected to an intelligent monitoring unit is fixedly installed at the top of the shell. The motor shaft of the scraper drive motor extends into the shell and its end is fixedly connected to a scraper support frame extending to the lower part of the heating jacket. A liquid distribution plate is fixedly connected to the scraper support frame located inside the shell. A demister is fixed to the inner wall of the shell below the liquid distribution plate. Multiple sets of scrapers with gaps between them and the inner wall of the tube shell are fixedly connected to the scraper support frame located inside the film-forming heat exchange tube shell.

[0017] Furthermore, the scraper is made of 316L material, and the gap between it and the inner wall of the tube shell is 0.5~1mm.

[0018] Furthermore, the low-temperature scraped-plate drying evaporator includes a main body, inside which is an evaporator cylinder. A pressurized heating steam inlet is provided through the top of the main body of the evaporator cylinder. A secondary steam outlet is provided through the upper part of the main body of the evaporator cylinder. A pre-stage solid-liquid concentrate inlet and a drying mineral by-product outlet are provided through the lower part of the main body of the evaporator cylinder. An evaporator heating chamber is provided on the main body below the evaporator cylinder. A condensate outlet is provided on the heating chamber. A drive motor electrically connected to an intelligent monitoring unit is fixedly installed on the side wall of the main body below the heating chamber. A reducer is fixedly installed on the side wall of the evaporator cylinder and driven by the output shaft of the drive motor. A scraper support main shaft is fixedly connected to the end of the output shaft of the reducer. The end of the scraper support main shaft away from the output shaft of the reducer is rotatably mounted on the side wall of the evaporator cylinder. Multiple evaporator built-in scrapers are fixedly connected to the scraper support main shaft.

[0019] Furthermore, a liquid level sensor is fixedly installed on the inner wall of the condensate buffer tank, and the condensate delivery pump and the liquid level sensor are electrically connected to the intelligent monitoring unit.

[0020] This invention also provides a method for the low-temperature evaporation and concentration of medium- and high-temperature geothermal hot spring water for resource utilization, characterized in that the method employs the aforementioned low-temperature evaporation and concentration system for medium- and high-temperature geothermal hot spring water, and the method includes the following steps:

[0021] S1. Raw water insulation and transportation: Medium-high temperature and high hardness geothermal hot spring raw water with a water temperature of 50-70℃ and a hardness of 300-400mg / L enters the insulation raw water tank for buffering. When the water temperature is ≥60℃, the condensate is heated and recovered through a high-temperature heat exchanger and the temperature is finely adjusted to 50-55℃ by heat exchange with an evaporator. When the water temperature is greater than or equal to 50℃ and less than 60℃, the geothermal hot spring raw water directly enters the subsequent step S2 pure physical pretreatment.

[0022] S2. Pure physical pretreatment: The raw water is sequentially treated by 18kHz high-frequency pulse scale inhibition, multi-channel cyclone separation and 5μm precision filtration, and the hardness of the effluent is ≤50mg / L.

[0023] S3. Low-temperature high-concentration: After pretreatment, the water enters a scraped-film evaporator and is heated and evaporated by secondary steam supplied by an MVR steam compressor at 60-70℃ and 0.15-0.25 MPa. At an evaporation temperature of 45-55℃, the pretreated water with a feed flow rate of 5-10 L / min is forced to form a film and concentrate to 10-30 times. The metasilicic acid retention rate of the feed liquid, i.e., geothermal hot spring water, is ≥95%. Subsequently, the concentrate concentration is divided into low-concentration concentrate with a concentration greater than or equal to 10 times and less than 20 times, and high-concentration concentrate with a concentration greater than or equal to 20 times and less than 30 times, and then bottled separately.

[0024] S4. Solid-liquid concentrate treatment: The solid-liquid concentrate generated in the pre-stage enters the low-temperature scraped plate drying evaporator, where it is heated and crystallized by secondary steam supplied by the MVR steam compressor at 60-70℃ and 0.15-0.25Mpa, producing dried mineral by-products.

[0025] S5. Condensate Reuse: The condensate generated from evaporation by the scraped film evaporator and crystallization by the low-temperature scraped drying evaporator is reused in the pool or landscape according to its conductivity, achieving zero discharge.

[0026] Furthermore, in step S3, when the evaporation temperature of the scraped film evaporator is >55℃, the steam pressure of the MVR steam compressor is reduced; when the evaporation temperature of the scraped film evaporator is <45℃, the steam pressure of the MVR steam compressor is increased; when the viscosity of the liquid in the scraped film evaporator is >5mPa·s, the scraper speed is adjusted to 25~30r / min; when the viscosity of the liquid in the scraped film evaporator is ≤5mPa·s, the scraper speed is adjusted to 15r / min; when the concentration ratio is <10 times, the feed flow rate at the inlet of the scraped film evaporator is reduced; when the concentration ratio is >30 times, the feed flow rate at the inlet of the scraped film evaporator is increased; when the metasilicic acid retention rate in the geothermal hot spring water is <95%, the evaporation temperature is immediately reduced by 5℃ and maintained for 30min.

[0027] Furthermore, in step S4, when the moisture content of the dried minerals produced by crystallization in the low-temperature scraper drying evaporator is >5%, the scraper speed is increased to 18~20 r / min to extend the drying time; when the moisture content of the dried minerals is ≤5%, the low-temperature scraper drying evaporator automatically discharges the material into the mineral by-product collection box.

[0028] Furthermore, in step S5, when the conductivity of the condensate is <5μS / cm, it is reused for replenishing the soaking pool; when the conductivity of the condensate is 5~10μS / cm, it is reused for landscape irrigation.

[0029] Compared with existing technologies, the low-temperature evaporation and concentration resource utilization system and method for medium- and high-temperature geothermal hot spring water provided by this invention have the following advantages:

[0030] 1. Utilization of native heat energy: Efficiently utilizes the native heat energy of medium- and high-temperature geothermal hot spring water at 50-70℃. The raw water from the medium- and high-temperature geothermal hot spring at the wellhead is directly connected to this system. Through the buffering of the insulated raw water tank and the fine adjustment of the high-temperature heat exchanger, the loss of native heat energy is reduced (≤2% / h). No pre-cooling / reheating is required, and it is directly adapted to the low-temperature evaporation conditions of 45-55℃. This significantly reduces the energy consumption of evaporation and concentration, and the native heat energy utilization rate is ≥92%. It solves the pain point of "waste of native heat energy", achieves a significant reduction in system energy consumption, and energy-saving operation.

[0031] 2. Pure physical three-stage scale prevention: It adopts a pure physical process of "18kHz high-frequency pulse distortion calcium and magnesium crystallization + cyclone separation microcrystals + 5μm precision filtration" and is equipped with a scraped film evaporator with a scraper scraping speed of 15~30r / min. After treating high hardness raw water of 300~400mg / L, the hardness of the effluent is ≤50mg / L. There are no chemical additives or residues, which protects the naturalness and health and safety of geothermal hot spring water and solves the pain points of "high hardness scale formation + chemical scale pollution".

[0032] 3. Low-temperature high-concentration of health-preserving elements: Through low-temperature evaporation at 45-55℃ + forced film formation by scraped-film evaporator (residence time <30s, liquid film thickness of 0.5-1mm), 10-30 times concentration is achieved, while ensuring that the retention rate of health-preserving components such as metasilicic acid is ≥95%, solving the pain point of "the decay of health-preserving elements in traditional membrane concentration".

[0033] 4. MVR Energy Recycling and Energy Saving: Fully utilize the natural heat energy of raw water, and use one set of MVR steam compressors in parallel to compress the secondary steam output from the front scraped film evaporator and the terminal low-temperature scraped drying evaporator to 60-70℃ and 0.15-0.25MPa for recycling. The latent heat utilization rate is ≥95%, and only a small amount of electricity is needed to supplement it, which greatly reduces energy consumption and solves the problem of "high energy consumption of traditional processes".

[0034] 5. Direct Drying and Recovery of Solid-Liquid Concentrates: A low-temperature scraped-plate dryer is used to directly treat the solid-liquid mixture discharged from the pre-evaporation stage. A parallel secondary steam circulation heating process is used with an MVR steam compressor. Low-temperature drying and crystallization at 50-60℃ + scraper stirring at 10-20 r / min produces dried mineral by-products with a moisture content of ≤5%, replacing the traditional nanofiltration desalination + centrifugation + drying process. The energy consumption for processing one ton of dried mineral by-products is reduced by 85%, solving the problem of "high energy consumption in end-of-pipe solid-liquid treatment".

[0035] 6. Full recovery and zero discharge: Construct a closed loop of "raw water → low-concentration / high-concentration concentrate → dried minerals → full recycling of condensate", with a condensate recycling rate of ≥99%, graded utilization of low-concentration (10-20 times) / high-concentration (20-30 times) concentrate, and direct recovery of dried mineral by-products, to realize the full value chain utilization and zero discharge of geothermal hot spring resources, and solve the problem of "single resource utilization". Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the process structure of the low-temperature evaporation and concentration resource utilization system for medium- and high-temperature geothermal hot spring water provided by the present invention.

[0037] Figure 2 This is a schematic diagram of the energy cycle of the MVR steam compressor parallel evaporation energy-saving system provided by the present invention.

[0038] Figure 3This is a schematic diagram of the scraped thin-film evaporator structure provided by the present invention.

[0039] Figure 4 This is a schematic diagram of the low-temperature scraper drying evaporator provided by the present invention.

[0040] In the diagram, 11. Medium- and high-temperature geothermal hot spring raw water pipeline; 12. Insulated raw water tank; 13. Raw water pump; 14. High-temperature heat exchanger; 15. Main circuit switch valve; 16. Heat exchange switch valve; 21. High-frequency pulse physical scale inhibitor; 22. Multi-channel cyclone separator; 23. High-temperature precision filter; 31. Scraped film evaporator; 311. Shell; 3111. Inlet; 3112. Secondary steam outlet; 3113. Concentrate outlet. 3114. Solid-liquid concentrate outlet; 312. Film-forming heat exchanger tube shell; 313. Heating jacket; 3131. Steam inlet; 3132. Condensate outlet; 314. Scraper drive motor; 315. Scraper support frame; 316. Liquid distribution tray; 317. Demister; 318. Scraper; 32. MVR steam compressor; 33. Hot spring concentrate outlet pump; 34. Low-concentration concentrate buffer tank; 341. Low-concentration concentrate inlet switch 35. Low-concentration concentrate filling pump; 36. Low-concentration concentrate filling pipeline; 37. High-concentration concentrate buffer tank; 371. High-concentration concentrate inlet switch valve; 38. High-concentration concentrate filling pump; 39. High-concentration concentrate filling pipeline; 41. Solid-liquid concentrate external discharge pump; 42. Low-temperature scraper drying evaporator; 421. Main body; 4211. Pressurized heating steam inlet; 4212. Secondary steam outlet; 4213. Solid-liquid concentrate inlet... 4214. Dried mineral by-product discharge port; 422. Evaporator barrel; 423. Evaporator heating chamber; 4231. Condensate discharge port; 424. Drive motor; 425. Reducer; 426. Scraper support shaft; 427. Evaporator built-in scraper; 43. Mineral by-product collection box; 44. Mineral by-product packaging system; 51. Condensate buffer tank; 52. Condensate transfer pump; 53. Condensate reuse system. Detailed Implementation

[0041] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0042] In the description of this invention, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] Please refer to Figure 1 and Figure 2 As shown, this invention provides a low-temperature evaporation and concentration resource recovery system for medium- and high-temperature geothermal hot spring water, comprising a primary thermal energy adaptation and raw water transportation unit, a purely physical pretreatment unit, a low-temperature high-concentration unit, a solid-liquid-concentrate treatment and mineral recovery unit, a condensate full reuse unit, and an intelligent monitoring unit; wherein,

[0045] The original thermal energy adaptation and raw water transportation unit includes a medium-high temperature geothermal hot spring raw water pipeline 11, an insulated raw water tank 12, a raw water pump 13, and a high temperature heat exchanger 14. The high temperature geothermal hot spring raw water pipeline 11, the insulated raw water tank 12, and the raw water pump 13 are connected sequentially through pipelines. The high temperature geothermal hot spring raw water pipeline 11 is adapted to transport geothermal hot spring raw water with a temperature of 50-70℃ and a hardness of 300-400 mg / L. The insulated raw water tank 12 is used to buffer high-hardness geothermal hot spring raw water. The raw water pump 13 has a flow rate of 10 m³ / L. 3 / h, temperature resistance ≤80℃; the outlet pipe of the raw water pump 13 is connected in sequence with a raw water temperature sensor and a main switch valve 15; the inlet and outlet of the high-temperature heat exchanger 14 are connected in parallel to the inlet and outlet pipes of the main switch valve 15; the inlet and outlet pipes of the high-temperature heat exchanger 14 are connected with heat exchange switch valves 16; the inlet of the high-temperature heat exchanger 14 is connected to the condensate output from the low-temperature high-concentration unit through a pipe; the heat exchange area of ​​the high-temperature heat exchanger 14 is 2m². 2Made of 316L steel, when the raw water temperature sensor detects that the temperature of the high-hardness geothermal hot spring raw water is ≥60℃, the intelligent monitoring unit will control the main switch valve 15 to close and the heat exchange switch valve 16 to open. At this time, the high-hardness geothermal hot spring raw water will be finely adjusted to 50-55℃ by using condensate heat exchange through the high-temperature heat exchanger 14. When the water temperature is greater than or equal to 50℃ and less than 60℃, the geothermal hot spring raw water directly enters the subsequent pure physical pretreatment unit for treatment. No pre-cooling is required throughout the process, 100% of the original heat energy is utilized, the original heat energy utilization rate is 92.5%, the energy consumption for temperature adjustment per ton of water is only 0.1kWh, and there is no raw water evaporation loss.

[0046] The pure physical pretreatment unit includes a high-frequency pulse physical scale inhibitor 21, a multi-channel cyclone separator 22, and a high-temperature precision filter 23 connected sequentially by pipelines. The inlet of the high-frequency pulse physical scale inhibitor 21 is connected to the outlet pipeline of the raw water pump 13. The high-frequency pulse physical scale inhibitor 21 has a power of 5kW and generates 18kHz high-frequency pulses that act on the high-hardness geothermal hot spring raw water, causing distortion of the hydration layer of calcium and magnesium ions, disrupting the thermodynamic conditions for their crystallization and nucleation, and forming loose, irregular microcrystals (rather than a dense scale layer). The flow velocity inside the multi-channel cyclone separator 22 is 2-3m / s, generating a centrifugal force of ≥1500g, which disperses the calcium and magnesium microcrystals (particle size) in the high-hardness geothermal hot spring raw water. The water (≥1μm) is separated from the water and discharged through the bottom outlet by gravity into the terminal evaporation and drying equipment (low-temperature scraped evaporator). The high-temperature precision filter 23 uses a 5μm ceramic filter element with a temperature resistance of ≤80℃. The high-temperature ceramic filter element traps residual microcrystals, ensuring that the hardness of the raw water entering the scraped film evaporator is ≤50mg / L, eliminating the risk of scaling in high-hardness geothermal hot spring raw water from the source. Operating parameters: Raw water hardness 300~400mg / L, after three-stage pure physical scale inhibition and descaling treatment, the calcium and magnesium microcrystal removal rate is 87%, the effluent hardness is 42~45mg / L, no chemical agents are added, and the pretreated water quality SDI≤3, which is fully compatible with the subsequent low-temperature evaporation scale prevention requirements.

[0047] The low-temperature high-concentration unit includes a scraped-film evaporator 31, an MVR steam compressor 32, a hot spring concentrate outlet pump 33, a low-concentration concentrate buffer tank 34, a low-concentration concentrate filling pump 35, a low-concentration concentrate filling pipeline 36, a high-concentration concentrate buffer tank 37, a high-concentration concentrate filling pump 38, and a high-concentration concentrate filling pipeline 39. The inlet of the scraped-film evaporator 31 is connected to the outlet of a high-temperature precision filter 23 via a pipeline. A feed flow control valve and a feed metasilicic acid analyzer are fixedly installed at the inlet of the scraped-film evaporator 31. The secondary evaporation of the scraped-film evaporator 31... The steam outlet is connected to the steam inlet of the MVR steam compressor 32. The steam outlet of the MVR steam compressor 32 is connected to the steam inlet of the scraped film evaporator 31 and the solid-liquid concentrate treatment and mineral recovery unit. The condensate outlet of the scraped film evaporator 31 is connected to the cold medium inlet of the high-temperature heat exchanger 14 via a pipeline. An evaporation temperature sensor, a feed liquid viscosity sensor, a feed liquid TDS sensor, and a discharge metasilicic acid analyzer are fixedly installed at the concentrate outlet of the scraped film evaporator 31. The concentrate outlet of the scraped film evaporator 31 is connected to the inlet of the hot spring concentrate outlet pump 33 via a pipeline. The outlet of the hot spring concentrate outlet pump 33 is connected via pipelines to the inlets of the low-concentration concentrate buffer tank 34 and the high-concentration concentrate buffer tank 37, respectively. A low-concentration concentrate inlet switch valve 341 is connected to the inlet pipeline of the low-concentration concentrate buffer tank 34, and a high-concentration concentrate inlet switch valve 371 is connected to the inlet pipeline of the high-concentration concentrate buffer tank 37. The outlet of the low-concentration concentrate buffer tank 34 is connected via pipelines to the low-concentration concentrate filling pump 35 and the low-concentration concentrate filling pipeline 36, respectively. The outlet of the high-concentration concentrate buffer tank 37 is connected via pipelines to the high-concentration concentrate filling pump 38 and the high-concentration concentrate filling pump 39, respectively. The high-concentration liquid filling pipeline 39; the scraped-film evaporator 31 is used for forced film formation and concentration, where the liquid forms a 0.5-1mm thick liquid film on the evaporator tube wall with a residence time of <30s, reducing the contact reaction between silica and the tube wall and preserving its activity; the MVR steam compressor 32 has a power of 37kW and is used to adiabatically compress (pressurize) the low-temperature secondary steam (temperature 45-50℃, pressure 0.09-0.12MPa) generated by the front-stage scraped-film evaporator 31 and the terminal low-temperature scraped drying evaporator 42 in the solid-liquid concentrate treatment and mineral recovery unit to 0.15-0.At 25 MPa (corresponding to a temperature of 60-70℃), the steam is used as the heating source for the two-stage evaporator. After the pressurized steam releases its latent heat, it condenses into water with a latent heat utilization rate of ≥95%. No additional steam input is required, which greatly reduces the system's energy consumption. The condensate is recycled to the utilization system. The scraped film evaporator 31 forces film formation and concentration to a low concentration of 10-20 times (TDS=50000-75000mg / L) and a high concentration of 20-30 times (TDS=100000-150000mg / L). When the feed liquid TDS sensor detects that the concentration of the concentrate has reached the threshold, the intelligent monitoring unit will control the low concentration inlet valve or the high concentration inlet valve to open, so that the concentrate can be automatically switched to the corresponding buffer tank. The feed flow control valve is used to reduce the feed flow rate at the inlet of the scraped-film evaporator when the concentration ratio is <10 times and to increase the feed flow rate at the inlet of the scraped-film evaporator when the concentration ratio is >30 times. The feed metasilicic acid analyzer is suitable for detecting the metasilicic acid retention rate in the feed liquid (geothermal hot spring water). The discharge metasilicic acid analyzer is suitable for detecting the metasilicic acid retention rate in the discharge liquid (geothermal hot spring water). The evaporation temperature sensor is suitable for detecting the evaporation temperature of the scraped-film evaporator 31 to adjust the steam pressure of the MVR steam compressor 32. The feed viscosity sensor is suitable for detecting the viscosity of the feed liquid in the scraped-film evaporator 31 to adjust the evaporator scraper rotation speed.

[0048] The solid-liquid concentrate treatment and mineral recovery unit includes a solid-liquid concentrate discharge pump 41, a low-temperature scraped-plate drying evaporator 42, a mineral by-product collection box 43, and a mineral by-product packaging system 44. The inlet of the solid-liquid concentrate discharge pump 41 is connected to the solid-liquid concentrate outlets of the scraped-plate thin-film evaporator 31 and the multi-channel cyclone separator 22 via pipelines. The outlet of the solid-liquid concentrate discharge pump 41 is connected to the pre-stage solid-liquid concentrate inlet of the low-temperature scraped-plate drying evaporator 42 via pipelines. The steam inlet of the low-temperature scraped-plate drying evaporator 42 is connected to the steam of the MVR steam compressor 32 via pipelines. The outlet connection is as follows: the secondary steam outlet of the low-temperature scraped-plate drying evaporator 42 is connected to the steam inlet of the MVR steam compressor 32; the inlet of the movable mineral by-product collection box 43 is connected to the dried mineral by-product outlet of the low-temperature scraped-plate drying evaporator 42; and the outlet of the mineral by-product collection box 43 is connected to the mineral by-product packaging system 44. The specific configuration of the mineral by-product packaging system 44 is prior art well known to those skilled in the art. A moisture sensor is also provided at the dried mineral by-product outlet of the low-temperature scraped-plate drying evaporator 42. The flow rate of the solid-liquid concentrated liquid discharge pump 41 is 0.5 m³ / s. 3 / h, temperature resistance ≤80℃; the solid-liquid mixed concentrate (solid content 5%~10%) discharged from the pre-stage scraped film evaporator 31 and multi-channel cyclone separator 22 enters the low-temperature scraped drying evaporator 42, where it is heated by secondary steam pressurized and heated by the MVR steam compressor 32 at 50~60℃ to evaporate water, causing the mineral salts in the high-hardness geothermal hot spring raw water to reach a supersaturated state for crystallization. The scrapers inside the low-temperature scraped drying evaporator 42 stir at a speed of 10~20r / min to avoid crystal agglomeration, and finally produce dried mineral by-products with a moisture content ≤5%, which can be sent to the downstream mineral by-product packaging system 44 without additional drying steps; the moisture sensor monitors the moisture content of the dried minerals produced by crystallization in the low-temperature scraped drying evaporator 42 in real time (online monitoring accuracy ±0.5%), and when the moisture content >5% At that time, the intelligent monitoring unit will control the low-temperature scraper drying evaporator 42 to increase its scraper speed to 18-20 r / min and extend the drying time. When the moisture content is ≤5%, it will automatically discharge the material into the mineral by-product collection box 43. The mineral recovery rate is 92.5% and the purity is 98.8%, which can be directly used for the packaging production of raw materials such as hot spring mud.

[0049] The condensate recycling unit includes a condensate buffer tank 51, a condensate transfer pump 52, and a condensate recycling system 53. A conductivity meter is fixedly installed on the condensate buffer tank 51. The inlet of the condensate buffer tank 51 is connected to the cold medium outlet of the high-temperature heat exchanger 14 and the condensate outlet of the low-temperature scraper drying evaporator 42. The outlet of the condensate buffer tank 51 is connected to the condensate transfer pump 52 and the condensate recycling system 53 via pipelines. The condensate recycling system 53 is divided into a soaking pool water replenishment branch and a landscape irrigation branch. When the conductivity meter detects that the condensate conductivity is <5μS / cm, it is recycled for soaking pool water replenishment through the soaking pool water replenishment branch. When the detected condensate conductivity is 5~10μS / cm, it is recycled for landscape irrigation through the landscape irrigation branch. The condensate recycling rate is 99.3%, and the water quality meets the GB / T18921-2022 "Standards for Drinking Water Quality", achieving zero discharge.

[0050] The intelligent monitoring unit is electrically connected to the raw water pump 13, the scraped thin film evaporator 31, the MVR steam compressor 32, the low-temperature scraped drying evaporator 42, the metasilicic acid analyzer (including the feed metasilicic acid analyzer and the discharge metasilicic acid analyzer), each pump valve and sensor, so as to control the relevant equipment and pump valves. The intelligent monitoring unit can be implemented using an existing PLC controller. The stability control accuracy during operation is ≥94%, and the operation and maintenance cost is reduced by ≥30% compared with manual operation.

[0051] As a specific embodiment, the volume of the insulated raw water tank 12 is 4m³. 3Its inner wall is equipped with a polyurethane insulation layer with a thickness of ≥50mm and a heat loss of ≤1.8% / h, which can effectively keep the high-hardness geothermal hot spring raw water in the buffer.

[0052] For a specific embodiment, please refer to Figure 3 As shown, the scraped-film evaporator 31 includes a shell 311. The top of the shell 311 has a water inlet 3111 and a secondary steam outlet 3112. A film-forming heat exchange tube shell (316L material) 312 is integrally formed at the lower end of the shell 311. A heating jacket 313 is fixed to the outer wall of the film-forming heat exchange tube shell 312. The heating jacket 313 provides space for heat transfer of heating steam. A steam inlet 3131 is located on the upper part of one side of the heating jacket 313, and a condensate outlet 3132 is located on the lower part of the other side of the heating jacket 313. A concentrate outlet 3113 is located below the condensate outlet 3132 on the lower part of the shell 311. A solid-liquid concentrate outlet 3114 is located at the bottom of the shell 311. A scraper drive motor 314, electrically connected to an intelligent monitoring unit, is fixedly installed at the top of the shell 311. The scraper... A drive motor 314 provides power to the scraper assembly. The motor shaft of the scraper drive motor 314 extends into the housing 311, and its end is fixedly connected to a scraper support frame 315 extending below the heating jacket 313. A liquid distribution plate 316 is fixedly connected to the scraper support frame 315 located inside the housing 311. The liquid distribution plate 316 is used for slow-flow liquid distribution. A demister 317 is fixedly connected to the inner wall of the housing 311 below the liquid distribution plate 316. The demister 317 is used for steam and water demisting. Multiple sets of scrapers 318 are fixedly connected to the scraper support frame 315 located inside the film-forming heat exchange tube shell 312, with gaps between them and the inner wall of the tube shell. The scrapers rotate at an adjustable speed of 15-30 r / min, adhering to the film-forming heat exchange tube wall 312, scraping away slightly attached floating scale in real time, maintaining tube wall cleanliness, and ensuring a stable heat transfer coefficient ≥3200 W / (m²). 2 •℃), enabling long-term continuous maintenance-free operation of the system. Since the thermal stability threshold of metasilicic acid is 60℃ (when it exceeds 60℃, silicic acid polymerizes and its activity decreases), the evaporation temperature of the scraped thin-film evaporator 31 in this invention is controlled at 45-55℃ to avoid the thermal decomposition range. Accordingly, the metasilicic acid retention rate in geothermal hot spring water reaches 95.8%-96.1%, and the concentration factor is stable at 22-25 times, which is more than 175% higher than that of single-stage membrane concentration.

[0053] As a specific embodiment, the scraper 318 is made of 316L material, and four sets can be set. The gap between the scraper and the inner wall of the tube shell is 0.5~1mm, which can effectively scrape off the slightly attached floating dirt and keep the tube wall clean.

[0054] For a specific embodiment, please refer to Figure 4As shown, the low-temperature scraped-plate drying evaporator 42 includes a main body 421, inside which is an evaporator cylinder 422. The evaporator cylinder provides space for the evaporation and crystallization of the evaporating liquid. A pressurized heating steam inlet 4211 penetrates the top of the main body 421 of the evaporator cylinder 422. A secondary steam outlet 4212 penetrates the upper part of the main body 421 of the evaporator cylinder 422. A pre-stage solid-liquid concentrate inlet 4213 and a drying mineral by-product outlet 4214 are respectively connected to the lower part of the main body 421 of the evaporator cylinder 422. An evaporator heating chamber 423 is provided on the lower part of the main body 421 of the evaporator cylinder 422. The evaporator heating chamber 423 provides space for heating steam and condensate outside the cylinder. A cooling system is provided on the evaporator heating chamber 423. A condensate outlet 4231 is provided. A drive motor 424 electrically connected to an intelligent monitoring unit is fixedly installed on the side wall of the main body 421 below the evaporator heating chamber 423. A reducer 425, which is driven by the output shaft of the drive motor 424 (e.g., via a belt), is fixedly installed on the side wall of the evaporator cylinder 422. A scraper support shaft 426 is fixedly connected to the end of the output shaft of the reducer 425. The reducer 425 is used to reduce the power of the drive motor 424 and transmit it to the scraper support shaft 426. The end of the scraper support shaft 426 away from the output shaft of the reducer is rotatably mounted on the side wall of the evaporator cylinder 422. Multiple evaporator built-in scrapers 427 are fixedly connected to the scraper support shaft 426. The evaporator built-in scrapers 427 are used to stir the liquid and scrape off the dried mineral by-products in the cylinder in real time. In this embodiment, by stirring with a scraper at a speed of 10-20 r / min and evaporating water at 50-60°C using secondary steam heating with an MVR steam compressor 32, the mineral salts in the high-hardness geothermal hot spring raw water can reach a supersaturated state for crystallization, and finally produce dried mineral by-products with a water content of ≤5%.

[0055] As a specific embodiment, a liquid level sensor is fixedly installed on the inner wall of the condensate buffer tank 51. The condensate delivery pump 52 and the liquid level sensor are electrically connected to the intelligent monitoring unit. The liquid level sensor detects the condensate level in the condensate buffer tank 51 in real time. The intelligent monitoring unit controls the start and stop of the condensate delivery pump 52 according to the detected condensate level. Specifically, the condensate delivery pump 52 is started when the liquid level in the condensate buffer tank 51 is ≥80%, and stops delivery when it is ≤20%.

[0056] This invention also provides a method for the low-temperature evaporation and concentration of medium- and high-temperature geothermal hot spring water for resource utilization. This method utilizes the aforementioned low-temperature evaporation and concentration system for medium- and high-temperature geothermal hot spring water, and includes the following steps:

[0057] S1. Raw water insulation and transportation: Medium-high temperature and high hardness geothermal hot spring raw water with a water temperature of 50-70℃ and a hardness of 300-400mg / L enters the insulation raw water tank for buffering. When the water temperature is ≥60℃, the condensate is heated and recovered through a high-temperature heat exchanger and the temperature is finely adjusted to 50-55℃ by heat exchange with an evaporator. When the water temperature is greater than or equal to 50℃ and less than 60℃, the geothermal hot spring raw water directly enters the subsequent step S2 pure physical pretreatment.

[0058] S2. Pure physical pretreatment: The raw water is sequentially treated by 18kHz high-frequency pulse scale inhibition, multi-channel cyclone separation and 5μm precision filtration, and the hardness of the effluent is ≤50mg / L.

[0059] S3. Low-temperature high-concentration: After pretreatment, the water enters a scraped-film evaporator and is heated and evaporated by secondary steam supplied by an MVR steam compressor at 60-70℃ and 0.15-0.25 MPa. At an evaporation temperature of 45-55℃, the pretreated water with a feed flow rate of 5-10 L / min is forced to form a film and concentrate to 10-30 times. The metasilicic acid retention rate of the feed liquid, i.e., geothermal hot spring water, is ≥95%. Subsequently, the concentrate concentration is divided into low-concentration concentrate with a concentration greater than or equal to 10 times and less than 20 times, and high-concentration concentrate with a concentration greater than or equal to 20 times and less than 30 times, and then bottled separately.

[0060] S4. Solid-liquid concentrate treatment: The solid-liquid concentrate generated in the previous stage enters the low-temperature scraped plate drying evaporator, where it is heated and crystallized using secondary steam supplied by the MVR steam compressor at 60-70°C and 0.15-0.25 MPa to produce dried mineral by-products. It should be noted that the MVR steam compressor described in steps S3 and S4 above, which heats and pressurizes the secondary steam to provide the heat source for evaporation, is under normal continuous operation. When starting up for the first time, it is necessary to rely on the secondary steam generated by the continuous evaporation of the medium and low temperature solution in the scraped film evaporator and the low-temperature scraped plate drying evaporator to establish the steam-material balance from the secondary steam to the medium and high temperature steam. In short, the MVR steam compressor cannot continuously generate a sufficient amount of stable heating steam from the beginning.

[0061] S5. Condensate Reuse: The condensate generated from evaporation by the scraped film evaporator and crystallization by the low-temperature scraped drying evaporator is reused in the pool or landscape according to its conductivity, achieving zero discharge.

[0062] In a specific embodiment, in step S3, when the evaporation temperature of the scraped film evaporator is >55℃, the steam pressure of the MVR steam compressor is reduced; when the evaporation temperature of the scraped film evaporator is <45℃, the steam pressure of the MVR steam compressor is increased. This steam pressure adjustment is achieved by controlling the MVR steam compressor through an intelligent monitoring unit. When the viscosity of the liquid in the scraped film evaporator is >5 mPa·s, the scraper speed is adjusted to 25~30 r / min; when the viscosity of the liquid in the scraped film evaporator is ≤5 mPa·s, the scraper speed is adjusted to 15 r / min. The scraper speed adjustment is achieved by controlling the scraper drive motor 314 through the intelligent monitoring unit; when the concentration ratio is <10 times, the feed flow rate at the inlet of the scraper-type thin film evaporator is reduced; when the concentration ratio is >30 times, the feed flow rate at the inlet of the scraper-type thin film evaporator is increased. The feed flow rate adjustment at the inlet of the scraper-type thin film evaporator here is achieved by controlling the feed flow control valve through the intelligent monitoring unit; when the metasilicic acid retention rate in the geothermal hot spring water is <95%, the evaporation temperature is immediately reduced by 5°C and maintained for 30 minutes. The evaporation temperature adjustment here is achieved by controlling the scraper-type thin film evaporator through the intelligent monitoring unit.

[0063] In a specific embodiment, in step S4, when the moisture content of the dried minerals produced by crystallization in the low-temperature scraper drying evaporator is >5%, the scraper speed is increased to 18~20 r / min to extend the drying time. The scraper speed adjustment here is achieved by controlling the drive motor 424 through the intelligent monitoring unit. When the moisture content of the dried minerals is ≤5%, the low-temperature scraper drying evaporator automatically discharges the material into the mineral by-product collection box.

[0064] In a specific embodiment, in step S5, when the conductivity of the condensate is <5μS / cm, it is reused for replenishing the soaking pool; when the conductivity of the condensate is 5~10μS / cm, it is reused for landscape irrigation.

[0065] To better demonstrate the technical effects of this invention, the applicant conducted a concentration and resource recovery experiment on existing high-hardness geothermal hot spring water (300mg / L~400mg / L) using this system and method. The specific experimental test data are as follows:

[0066] Table 1 Core performance data under high-hardness geothermal wet spring water conditions

[0067] Raw water conditions Water temperature (°C) Raw water hardness (mg / L) Hardness after pretreatment (mg / L) Concentration factor Metasilicic acid retention rate Typical high hardness working conditions 55 350 42 22 95.80% Ultra-high hardness working conditions 58 400 45 20 95.20% Low temperature and high hardness working conditions 50 300 38 25 96.10%

[0068] Table 2. Experimental data on the retention of health and wellness components (focusing on overcoming the pain points of membrane concentration)

[0069] Raw water health and wellness component content Metasilicic acid (mg / L) Lithium (μg / L) Strontium (μg / L) Concentration factor Metasilicic acid content in the concentrate (mg / L) Metasilicic acid retention rate of the present invention Membrane Concentration (8x) Metasilicic Acid Retention Rate High hardness raw water value 1 38.6 52.8 126.5 22 times 812.3 95.80% 68.20% High hardness raw water value 2 42.3 58.5 135.2 25 times 986.7 96.10% 68.20%

[0070] Table 3. Energy-saving and economic experimental data (daily processing of 10 tons of high-hardness geothermal hot spring water)

[0071] index Effects of the invention Membrane concentration + nanofiltration desalination + centrifugation + drying Traditional multi-effect evaporation + centrifugation + drying Annual savings / value enhancement (based on daily treatment of 10 tons of raw water) Main energy-consuming equipment Circulating pumps, MVR units Cooling equipment, multi-stage high-pressure pumps, centrifuges, drying equipment Heater (external steam supply), circulating pump, vacuum pump, centrifuge, drying equipment Different processes require different configurations of energy-consuming equipment. Energy consumption per ton of water (kWh) 10.8 22.5+15=37.5 40+8=48 Annual electricity savings compared to membrane concentration: 10 × 365 × (37.5 - 10.8) × 0.6 = 58,473 yuan. Annual electricity savings compared to traditional multi-effect evaporation: 10 × 365 × (48 - 10.8) × 0.6 = 81,468 yuan. Annual maintenance cost (ten thousand yuan) 1.2 8.5 (including membrane replacement) 6.8 (including cleaning) Annual maintenance cost savings compared to membrane concentration: 85,000 - 12,000 = 73,000 yuan; annual maintenance cost savings compared to traditional multi-effect evaporation: 68,000 - 12,000 = 56,000 yuan. Annual output value of resource utilization and recycling (ten thousand yuan / year) 140.2 (Concentrate and mineral byproducts) 86.4 (Single concentrate only) 68.2 (Concentrate only) Annual value increase compared to membrane concentration: 140.2 - 86.4 = 53.8 million yuan; Annual value increase compared to traditional multi-effect evaporation: 140.2 - 68.2 = 72 million yuan.

[0072] Compared with existing technologies, the low-temperature evaporation and concentration resource utilization system and method for medium- and high-temperature geothermal hot spring water provided by this invention have the following advantages:

[0073] 1. Utilization of native heat energy: Efficiently utilizes the native heat energy of medium- and high-temperature geothermal hot spring water at 50-70℃. The raw water from the medium- and high-temperature geothermal hot spring at the wellhead is directly connected to this system. Through the buffering of the insulated raw water tank and the fine adjustment of the high-temperature heat exchanger, the loss of native heat energy is reduced (≤2% / h). No pre-cooling / reheating is required, and it is directly adapted to the low-temperature evaporation conditions of 45-55℃. This significantly reduces the energy consumption of evaporation and concentration, and the native heat energy utilization rate is ≥92%. It solves the pain point of "waste of native heat energy", achieves a significant reduction in system energy consumption, and energy-saving operation.

[0074] 2. Pure physical three-stage scale prevention: It adopts a pure physical process of "18kHz high-frequency pulse distortion calcium and magnesium crystallization + cyclone separation microcrystals + 5μm precision filtration" and is equipped with a scraped film evaporator with a scraper scraping speed of 15~30r / min. After treating high hardness raw water of 300~400mg / L, the hardness of the effluent is ≤50mg / L. There are no chemical additives or residues, which protects the naturalness and health and safety of geothermal hot spring water and solves the pain points of "high hardness scale formation + chemical scale pollution".

[0075] 3. Low-temperature high-concentration of health-preserving elements: Through low-temperature evaporation at 45-55℃ + forced film formation by scraped-film evaporator (residence time <30s, liquid film thickness of 0.5-1mm), 10-30 times concentration is achieved, while ensuring that the retention rate of health-preserving components such as metasilicic acid is ≥95%, solving the pain point of "the decay of health-preserving elements in traditional membrane concentration".

[0076] 4. MVR Energy Recycling and Energy Saving: Fully utilize the natural heat energy of raw water, and use one set of MVR steam compressors in parallel to compress the secondary steam output from the front scraped film evaporator and the terminal low-temperature scraped drying evaporator to 60-70℃ and 0.15-0.25MPa for recycling. The latent heat utilization rate is ≥95%, and only a small amount of electricity is needed to supplement it, which greatly reduces energy consumption and solves the problem of "high energy consumption of traditional processes".

[0077] 5. Direct Drying and Recovery of Solid-Liquid Concentrates: A low-temperature scraped-plate dryer is used to directly treat the solid-liquid mixture discharged from the pre-evaporation stage. A parallel secondary steam circulation heating process is used with an MVR steam compressor. Low-temperature drying and crystallization at 50-60℃ + scraper stirring at 10-20 r / min produces dried mineral by-products with a moisture content of ≤5%, replacing the traditional nanofiltration desalination + centrifugation + drying process. The energy consumption for processing one ton of dried mineral by-products is reduced by 85%, solving the problem of "high energy consumption in end-of-pipe solid-liquid treatment".

[0078] 6. Full recovery and zero discharge: Construct a closed loop of "raw water → low-concentration / high-concentration concentrate → dried minerals → full recycling of condensate", with a condensate recycling rate of ≥99%, graded utilization of low-concentration (10-20 times) / high-concentration (20-30 times) concentrate, and direct recovery of dried mineral by-products, to realize the full value chain utilization and zero discharge of geothermal hot spring resources, and solve the problem of "single resource utilization".

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A low-temperature evaporation and concentration resource utilization system for medium- and high-temperature geothermal hot spring water, characterized in that, It includes a primary heat energy adaptation and raw water delivery unit, a purely physical pretreatment unit, a low-temperature high-concentration unit, a solid-liquid-concentrate treatment and mineral recovery unit, a condensate full reuse unit, and an intelligent monitoring unit; among which, The original thermal energy adaptation and raw water delivery unit includes a medium-high temperature geothermal hot spring raw water pipeline, an insulated raw water tank, a raw water pump, and a high temperature heat exchanger. The high temperature geothermal hot spring raw water pipeline, the insulated raw water tank, and the raw water pump are connected in sequence through pipelines. A raw water temperature sensor and a main switch valve are connected in sequence to the outlet pipeline of the raw water pump. The inlet and outlet of the high temperature heat exchanger are connected in parallel to the pipelines at the inlet and outlet of the main switch valve through pipelines. A heat exchange switch valve is connected to the inlet and outlet pipelines of the high temperature heat exchanger. The cold medium inlet of the high temperature heat exchanger is connected to the condensate output from the low temperature high concentration unit through a pipeline. The pure physical pretreatment unit includes a high-frequency pulse physical scale inhibitor, a multi-channel cyclone separator, and a high-temperature precision filter connected in sequence through pipelines. The inlet of the high-frequency pulse physical scale inhibitor is connected to the outlet pipeline of the raw water pump. The low-temperature high-concentration unit includes a scraped-film evaporator, an MVR steam compressor, a hot spring concentrate outlet pump, a low-concentration concentrate buffer tank, a low-concentration concentrate filling pump, a low-concentration concentrate filling pipeline, a high-concentration concentrate buffer tank, a high-concentration concentrate filling pump, and a high-concentration concentrate filling pipeline. The inlet of the scraped-film evaporator is connected to the outlet of a high-temperature precision filter via a pipeline. A feed flow control valve and a feed metasilicic acid analyzer are fixedly installed at the inlet of the scraped-film evaporator. The secondary steam outlet of the scraped-film evaporator is connected to the steam inlet of the MVR steam compressor. The steam outlet of the MVR steam compressor is connected to the steam inlet of the scraped-film evaporator and the solid-liquid concentrate treatment and mineral recovery unit. The condensate outlet of the scraped-film evaporator is connected to the cold medium inlet of a high-temperature heat exchanger via a pipeline. The scraped-film evaporator is equipped with an evaporation temperature sensor, a feed liquid viscosity sensor, a feed liquid TDS sensor, and a discharge metasilicic acid analyzer at its concentrate outlet. The concentrate outlet of the scraped-film evaporator is connected to the inlet of a hot spring concentrate outlet pump via a pipeline. The outlet of the hot spring concentrate outlet pump is connected to the inlets of a low-concentration concentrate buffer tank and a high-concentration concentrate buffer tank via pipelines. A low-concentration concentrate inlet switch valve is connected to the inlet pipeline of the low-concentration concentrate buffer tank, and a high-concentration concentrate inlet switch valve is connected to the inlet pipeline of the high-concentration concentrate buffer tank. The outlet of the low-concentration concentrate buffer tank is connected to a low-concentration concentrate filling pump and a low-concentration concentrate filling pipeline in sequence via pipelines, and the outlet of the high-concentration concentrate buffer tank is connected to a high-concentration concentrate filling pump and a high-concentration concentrate filling pipeline in sequence via pipelines. The solid-liquid concentrate treatment and mineral recovery unit includes a solid-liquid concentrate discharge pump, a low-temperature scraped-plate drying evaporator, a mineral by-product collection box, and a mineral by-product packaging system. The inlet of the solid-liquid concentrate discharge pump is connected to the solid-liquid concentrate outlet of the scraped-plate thin-film evaporator and the multi-channel cyclone separator via a pipeline. The outlet of the solid-liquid concentrate discharge pump is connected to the pre-stage solid-liquid concentrate inlet of the low-temperature scraped-plate drying evaporator via a pipeline. The steam inlet of the low-temperature scraped-plate drying evaporator is connected to the steam outlet of the MVR steam compressor via a pipeline. The secondary steam outlet of the low-temperature scraped-plate drying evaporator is connected to the steam inlet of the MVR steam compressor. The inlet of the mineral by-product collection box is connected to the dried mineral by-product outlet of the low-temperature scraped-plate drying evaporator. The outlet of the mineral by-product collection box is connected to the mineral by-product packaging system. A moisture sensor is also installed at the dried mineral by-product outlet of the low-temperature scraped-plate drying evaporator. The condensate recycling unit includes a condensate buffer tank, a condensate delivery pump, and a condensate recycling system. A conductivity meter is fixedly installed on the condensate buffer tank. The inlet of the condensate buffer tank is connected to the cold medium outlet of the high-temperature heat exchanger and the condensate outlet of the low-temperature scraper drying evaporator. The outlet of the condensate buffer tank is connected to the condensate delivery pump and the condensate recycling system in sequence through pipelines. The condensate recycling system is divided into a pool water replenishment branch and a landscape irrigation branch. The intelligent monitoring unit is electrically connected to the raw water pump, scraped film evaporator, MVR steam compressor, low-temperature scraped drying evaporator, metasilicic acid analyzer, various pumps, valves and sensors.

2. The low-temperature evaporation and concentration resource utilization system for medium- and high-temperature geothermal hot spring water according to claim 1, characterized in that, The inner wall of the insulated raw water tank is provided with a polyurethane insulation layer with a thickness of ≥50mm and a heat loss of ≤1.8% / h.

3. The low-temperature evaporation and concentration resource utilization system for medium- and high-temperature geothermal hot spring water according to claim 1, characterized in that, The scraped-film evaporator includes a shell with a water inlet and a secondary steam outlet at the top. A film-forming heat exchange tube shell is integrally formed at the lower end of the shell. A heating jacket is fixed to the outer wall of the film-forming heat exchange tube shell. A steam inlet is provided on the upper part of one side of the heating jacket, and a condensate outlet is provided on the lower part of the other side of the heating jacket. A concentrate outlet is provided at the lower part of the shell below the condensate outlet. A solid-liquid concentrate outlet is provided at the bottom of the shell. A scraper drive motor electrically connected to an intelligent monitoring unit is fixedly installed at the top of the shell. The motor shaft of the scraper drive motor extends into the shell and its end is fixedly connected to a scraper support frame extending to the lower part of the heating jacket. A liquid distribution plate is fixedly connected to the scraper support frame located inside the shell. A demister is fixed to the inner wall of the shell below the liquid distribution plate. Multiple sets of scrapers with gaps between them and the inner wall of the tube shell are fixedly connected to the scraper support frame located inside the film-forming heat exchange tube shell.

4. The low-temperature evaporation and concentration resource utilization system for medium- and high-temperature geothermal hot spring water according to claim 3, characterized in that, The scraper is made of 316L material, and the gap between it and the inner wall of the tube is 0.5~1mm.

5. The low-temperature evaporation and concentration resource utilization system for medium- and high-temperature geothermal hot spring water according to claim 1, characterized in that, The low-temperature scraper drying evaporator includes a main body, inside which is an evaporator cylinder. A pressurized heating steam inlet is provided through the top of the main body of the evaporator cylinder. A secondary steam outlet is provided through the upper part of the main body of the evaporator cylinder. A pre-stage solid-liquid concentrate inlet and a drying mineral by-product outlet are provided through the lower part of the main body of the evaporator cylinder. An evaporator heating chamber is provided on the main body below the evaporator cylinder, and a condensate outlet is provided on the heating chamber. A drive motor electrically connected to an intelligent monitoring unit is fixedly installed on the side wall of the main body below the heating chamber. A reducer, driven by the output shaft of the drive motor, is fixedly installed on the side wall of the evaporator cylinder. A scraper support main shaft is fixedly connected to the end of the reducer's output shaft. The end of the scraper support main shaft away from the reducer's output shaft is rotatably mounted on the side wall of the evaporator cylinder. Multiple internal scrapers of the evaporator are fixedly connected to the scraper support main shaft.

6. The low-temperature evaporation and concentration resource utilization system for medium- and high-temperature geothermal hot spring water according to claim 1, characterized in that, A liquid level sensor is fixedly installed on the inner wall of the condensate buffer tank, and the condensate delivery pump and the liquid level sensor are electrically connected to the intelligent monitoring unit.

7. A method for the low-temperature evaporation and concentration of medium- and high-temperature geothermal hot spring water for resource utilization, characterized in that, This method employs the low-temperature evaporation and concentration resource recovery system for medium- and high-temperature geothermal hot spring water as described in any one of claims 1-6, and the method includes the following steps: S1. Raw water insulation and transportation: Medium-high temperature and high hardness geothermal hot spring raw water with a water temperature of 50-70℃ and a hardness of 300-400mg / L enters the insulation raw water tank for buffering. When the water temperature is ≥60℃, the condensate is heated and recovered through a high-temperature heat exchanger and the temperature is finely adjusted to 50-55℃ by heat exchange with an evaporator. When the water temperature is greater than or equal to 50℃ and less than 60℃, the geothermal hot spring raw water directly enters the subsequent step S2 pure physical pretreatment. S2. Pure physical pretreatment: The raw water is sequentially treated by 18kHz high-frequency pulse scale inhibition, multi-channel cyclone separation and 5μm precision filtration, and the hardness of the effluent is ≤50mg / L. S3. Low-temperature high-concentration: After pretreatment, the water enters a scraped-film evaporator and is heated and evaporated by secondary steam supplied by an MVR steam compressor at 60-70℃ and 0.15-0.25 MPa. At an evaporation temperature of 45-55℃, the pretreated water with a feed flow rate of 5-10 L / min is forced to form a film and concentrate to 10-30 times. The metasilicic acid retention rate of the feed liquid, i.e., geothermal hot spring water, is ≥95%. Subsequently, the concentrate concentration is divided into low-concentration concentrate with a concentration greater than or equal to 10 times and less than 20 times, and high-concentration concentrate with a concentration greater than or equal to 20 times and less than 30 times, and then bottled separately. S4. Solid-liquid concentrate treatment: The solid-liquid concentrate generated in the pre-stage enters the low-temperature scraped plate drying evaporator, where it is heated and crystallized by secondary steam supplied by the MVR steam compressor at 60-70℃ and 0.15-0.25Mpa, producing dried mineral by-products. S5. Condensate Reuse: The condensate generated from evaporation by the scraped film evaporator and crystallization by the low-temperature scraped drying evaporator is reused in the pool or landscape according to its conductivity, achieving zero discharge.

8. The method for low-temperature evaporation and concentration of medium- and high-temperature geothermal hot spring water for resource utilization according to claim 7, characterized in that, In step S3, when the evaporation temperature of the scraped film evaporator is >55℃, the steam pressure of the MVR steam compressor is reduced; when the evaporation temperature of the scraped film evaporator is <45℃, the steam pressure of the MVR steam compressor is increased. When the viscosity of the liquid in the scraped film evaporator is >5mPa·s, the scraper speed is adjusted to 25~30r / min; when the viscosity of the liquid in the scraped film evaporator is ≤5mPa·s, the scraper speed is adjusted to 15r / min. When the concentration ratio is <10 times, the feed flow rate at the inlet of the scraped film evaporator is reduced; when the concentration ratio is >30 times, the feed flow rate at the inlet of the scraped film evaporator is increased. When the metasilicic acid retention rate in the geothermal hot spring water is <95%, the evaporation temperature is immediately reduced by 5℃ and maintained for 30min.

9. The method for low-temperature evaporation and concentration of medium- and high-temperature geothermal hot spring water for resource utilization according to claim 7, characterized in that, In step S4, when the moisture content of the dried minerals produced by crystallization in the low-temperature scraper drying evaporator is >5%, the scraper speed is adjusted to 18~20 r / min to extend the drying time; when the moisture content of the dried minerals is ≤5%, the low-temperature scraper drying evaporator automatically discharges the material into the mineral by-product collection box.

10. The method for low-temperature evaporation and concentration of medium- and high-temperature geothermal hot spring water for resource utilization according to claim 7, characterized in that, In step S5, when the conductivity of the condensate is <5μS / cm, it is reused for replenishing the soaking pool; when the conductivity of the condensate is 5~10μS / cm, it is reused for landscape irrigation.

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