Reverse osmosis treatment system

Abstract

The utility model relates to the technical field of mine water concentration treatment, and provides a reverse osmosis treatment system which comprises a control system, a raw water booster pump, a precision filter, a plunger pump, a circulating pump, a plurality of groups of STRO membrane groups arranged in parallel, an internal circulation pressure reducing valve, an energy recovery device and a concentrated liquid external exhaust pneumatic valve, the raw water booster pump, the precision filter, the plunger pump, the circulating pump and the STRO membrane group are connected in sequence; effluent of each STRO membrane group is divided into a concentrated solution and a permeate, the permeate is discharged through a water production pneumatic valve, one part of the concentrated solution returns to an inlet of the circulating pump, and the other part of the concentrated solution is discharged after passing through the energy recovery device. According to the utility model, by designing the internal circulation system, the circulation flow can be increased, the membrane flux can be reduced, the stable and lasting operation of the system is ensured, meanwhile, the energy recovery efficiency can reach more than 97% by adding the energy recovery design, and the energy consumption is greatly reduced.

Description

Technical Field

[0001] This utility model relates to the field of mine water concentration and treatment technology, specifically to a reverse osmosis treatment system. Background Technology

[0002] Currently, mine wastewater resource utilization is the best option for solving the problems of water shortage in coal mines and environmental pollution caused by mine wastewater, achieving a balance of social, environmental, and economic benefits. With scientific advancements and increased public awareness of environmental protection, mine water resource utilization has gained widespread attention from coal mining enterprises. To effectively purify mine wastewater, it is generally necessary to select a suitable purification process based on the type of wastewater and the composition of pollutants. Deep treatment membrane concentration is an essential component, typically employing a "stepwise synergistic pretreatment + multi-stage coupled membrane concentration" process. Among these, three-stage membrane concentration is less commonly used due to its less mature technology. A three-stage membrane concentration system can significantly reduce concentrate production, possessing significant theoretical and practical value for improving scientific management, reducing production costs, and achieving efficient operation.

[0003] Three-stage membrane concentration systems, as a crucial unit in the resource recovery of mine wastewater, are technologically advanced, offer high desalination rates, and significantly reduce concentrate production, making them a potential final treatment method for mine wastewater resource recovery. However, they also suffer from high system design complexity, high operating costs, and complex maintenance. The TDS of the influent to a three-stage membrane concentration system is approximately 60,000 mg / L, while the TDS of the final concentrated brine can reach over 110,000 mg / L, with a maximum osmotic pressure as high as 12 MPa. This demonstrates that the three-stage reverse osmosis system operates in extremely poor water quality conditions and consumes a very high amount of energy.

[0004] Three-stage membrane concentration systems generally employ ultra-high pressure reverse osmosis systems with energy recovery devices, primarily spiral wound RO and DTRO systems. Spiral wound RO systems are generally more commonly used in the secondary concentration stage. These systems utilize turbine-type energy recovery devices and offer relatively good feed water quality at lower pressures. However, their process design and performance in the tertiary concentration stage are insufficient to meet production requirements in terms of operating pressure and desalination rate. Ultra-high pressure DTRO systems can meet the requirements in terms of operating pressure and desalination rate, but they suffer from drawbacks such as complex structure, high failure rate, high operating and maintenance costs, and susceptibility to fouling that is difficult to chemically clean.

[0005] Originally designed for treating landfill leachate, the network-type reverse osmosis (STRO) membrane, as an upgrade to DTRO, offers several key advantages beyond those of DTRO membranes: stronger resistance to fouling due to its open flow channels; approximately three times the filtration area of ​​a single membrane element compared to DTRO elements, reducing the number of elements by two-thirds for the same treatment capacity; lower pressure loss and energy consumption; and more convenient and simpler maintenance. Currently, there are no design schemes or application cases for 12MPa STRO membrane systems in China for the field of mine water resource recovery.

[0006] Currently, the most common ultra-high pressure reverse osmosis system is the DTRO / STRO system, which is mainly used in landfill leachate treatment and rarely involved in the zero-discharge resource recovery of coal mine wastewater. Although the operating pressure of this system can reach 120 Bar, the two processes are completely different, requiring a redesign of the relevant structure based on the mine wastewater. For example, patent documents CN113173661B and CN110294551A disclose related processes, but the above designs are not applicable to the three-stage concentration of mine wastewater in zero discharge, and the existing system design lacks energy recovery and reuse, resulting in high energy consumption. Utility Model Content

[0007] In view of the deficiencies in the existing technology, the purpose of this utility model is to provide a reverse osmosis treatment system.

[0008] The reverse osmosis treatment system provided by this utility model includes a raw water booster pump, a precision filter, a plunger pump, a circulation pump, multiple sets of parallel-arranged STRO membrane modules, an internal circulation pressure reducing valve, an energy recovery device, and a concentrate external exhaust valve.

[0009] The raw water booster pump, precision filter, plunger pump, circulation pump, and STRO membrane module are connected in sequence.

[0010] The effluent from each STRO membrane module is divided into concentrate and permeate. The permeate is discharged sequentially through the fourth and fifth pipelines via the permeate pneumatic valve. Part of the concentrate from the STRO membrane module returns to the inlet of the circulation pump via the internal circulation pressure reducing valve, and the other part of the concentrate is discharged through the energy recovery device via the low-pressure concentrate discharge pipeline and the concentrate exhaust pneumatic valve.

[0011] Preferably, the concentrate exiting the STRO membrane module first enters the concentrate outlet pipeline, which is connected to the internal circulation pressure reducing valve via an internal circulation pipeline. The concentrate outlet pipeline is also connected to the first inlet of the energy recovery device via a high-pressure concentrate inlet pipeline, and the first outlet of the energy recovery device is connected to the low-pressure concentrate outlet pipeline. The concentrate outlet pipeline is also connected to the low-pressure concentrate outlet pipeline via a pressure regulating valve.

[0012] Preferably, it also includes a chemical cleaning pipeline, wherein the plunger pump and the circulation pump are connected through a third pipeline, and the chemical cleaning pipeline is connected to the third pipeline through a high-pressure cleaning pneumatic valve;

[0013] A small portion of the cleaning solution from the STRO membrane module enters the cleaning tank through the fifth pipeline and the cleaning solution return pneumatic valve at the product water end.

[0014] Most of the cleaning solution from the STRO membrane module enters the cleaning tank via the concentrate outlet pipeline, pressure regulating valve, and concentrate end cleaning solution return pneumatic valve.

[0015] Preferably, it also includes a flushing pneumatic valve, which is installed on the sixth pipeline. The raw water booster pump is connected to the precision filter through the first pipeline, and the sixth pipeline is connected to the first pipeline.

[0016] After the flushing water enters from the sixth pipeline, it flushes the STRO membrane module. A small portion of the flushing water then enters the wastewater tank through the fourth pipeline, the fifth pipeline, and the wastewater exhaust valve at the product water end.

[0017] Most of the flushing water is discharged into the wastewater tank through the concentrate outlet pipeline, the high-pressure concentrate inlet pipeline, the pressure regulating valve, and the wastewater exhaust valve at the concentrate end.

[0018] Preferably, the precision filter is connected to the plunger pump through a second pipeline. A portion of the low-pressure raw liquid in the second pipeline enters the second inlet of the energy recovery device after being pressurized through the low-pressure raw liquid inlet pipeline, and then exits from the second outlet of the energy recovery device. After passing through the high-pressure raw liquid outlet pipeline, it enters the inlet of the circulation pump.

[0019] Preferably, the raw water booster pump is connected to the precision filter through a first pipeline, and the dosing equipment is connected to the first pipeline through a dosing pipeline. The first pipeline is also equipped with an instrument assembly after the inlet pump, which includes at least one of the following detection components:

[0020] Flow meter;

[0021] Conductivity meter;

[0022] Pressure transmitter;

[0023] Pressure gauge;

[0024] Temperature sensor;

[0025] The fifth pipeline is equipped with a water production instrument assembly, which includes at least one of the following detection components:

[0026] Flow meter;

[0027] Pressure transmitter;

[0028] Pressure gauge;

[0029] Temperature sensor.

[0030] Preferably, each group of STRO membrane modules is equipped with a product water float flow meter on its outlet pipe.

[0031] Preferably, the motors of the plunger pump and the circulating pump are equipped with frequency converters.

[0032] Preferably, a scale inhibitor dosing point is provided on the first pipeline.

[0033] Preferably, a safety valve is provided on the outlet pipe of the plunger pump.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] This invention increases circulation flow and reduces membrane flux through an internal circulation system design, ensuring stable and continuous system operation. Simultaneously, it incorporates an energy recovery design, achieving an energy recovery efficiency of over 97%, significantly reducing energy consumption. This invention is suitable for higher TDS filtration and higher operating pressures, further concentrating the secondary concentrate to a TDS concentration exceeding 110,000 mg / L. The concentrate production is reduced by half compared to the secondary concentrate, saving substantial amounts of usable water resources and reducing the processing scale of downstream evaporation and crystallization equipment. This plays a crucial role in the resource recovery and zero-discharge of mine wastewater. Furthermore, this invention can operate stably and continuously under ultra-high pressure environments, protecting the membrane element's durability and lifespan. Attached Figure Description

[0036] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0037] Figure 1 This is a schematic diagram of the process flow of this utility model.

[0038] The diagram shows:

[0039] Raw water booster pump 1;

[0040] Instrument assembly 2 after the water inlet pump;

[0041] Precision filter 3;

[0042] Instrumentation assembly 4 after filter;

[0043] 5. Plunger pump;

[0044] Safety valve 6;

[0045] High-pressure pump post-instrument assembly 7;

[0046] Circulating pump 8;

[0047] Instrumentation assembly 9 after the circulating pump;

[0048] STRO membrane module 10;

[0049] 11. Water production float flow meter;

[0050] Water production instrument assembly 12;

[0051] Product water sampling port 13;

[0052] Water production pneumatic valve 14;

[0053] Concentrate outlet membrane line 15;

[0054] Internal circulation pipeline 16;

[0055] Internal circulation pressure reducing valve 17;

[0056] High-pressure concentrate inlet pipeline 18;

[0057] Energy recovery device 19;

[0058] High-pressure raw material outlet pipeline 20;

[0059] Low-pressure raw material inlet pipe 21;

[0060] Low-pressure concentrate discharge pipeline 22;

[0061] Pressure regulating valve 23;

[0062] Concentrate Instrumentation Components 24;

[0063] Concentrate external vent valve 25;

[0064] Chemical cleaning of pipeline 26;

[0065] Pneumatic valve 27 for backflow of cleaning fluid at the product water end;

[0066] Pneumatic valve 28 for return of concentrated liquid cleaning fluid;

[0067] Flushing pneumatic valve 29;

[0068] 30 exhaust valve for wastewater at the product water end;

[0069] Wastewater exhaust valve 31 at the concentrated liquid end;

[0070] Dosing line 32;

[0071] Clean the high-pressure pneumatic valve 33;

[0072] Concentrate Membrane Discharge Instrument Component 34;

[0073] Scale inhibitor dosing point 35;

[0074] First pipeline 101;

[0075] Second pipeline 102;

[0076] Third pipeline 103;

[0077] Fourth pipe 104;

[0078] Fifth pipeline 105;

[0079] Sixth pipeline 106;

[0080] A diagram illustrating the various symbols in the instrument assembly:

[0081] FI float flowmeter, FIT electromagnetic flowmeter, PI pressure gauge, PT pressure transmitter, TIT temperature sensor, NIT conductivity meter, pH meter. Detailed Implementation

[0082] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0083] This invention relates to the field of zero-discharge mine water resource utilization, particularly in the three-stage membrane concentration treatment stage. Specifically, it provides a reverse osmosis treatment system designed for three-stage concentration processes. Figure 1 As shown, the system includes a control system, a raw water booster pump 1, a precision filter 3, a plunger pump 5, a circulation pump 8, multiple sets of parallel-arranged STRO membrane modules 10, an internal circulation pressure reducing valve 17, an energy recovery device 19, and a concentrate external exhaust valve 25. The raw water booster pump 1, precision filter 3, plunger pump 5, circulation pump 8, and STRO membrane modules 10 are connected in sequence to realize the raw liquid filtration process. Specifically, the raw water booster pump 1 is connected to the precision filter 3, and the plunger pump is connected after the precision filter 3. Pump 5, after which the plunger pump 5 is connected to the circulation pump 8, the circulation pump 8 absorbs the booster water from the plunger pump 5, the energy recovery device 19 and the internal circulation pipeline 16 and pumps it to the STRO membrane module 10 for filtration. Multiple STRO membrane modules 10 are used in parallel. The water output of each STRO membrane module 10 is divided into concentrate and permeate. The permeate is discharged through the fourth pipeline 104 and the fifth pipeline 105 in sequence through the product water pneumatic valve 14. The fifth pipeline 105 is equipped with a product water sampling port 13, which can be used for sampling and testing.

[0084] Specifically, a portion of the concentrate from the STRO membrane module 10 returns to the inlet of the circulation pump 8 via the internal circulation pressure reducing valve 17, thus realizing the internal circulation process. The internal circulation is designed to adapt to the water quality environment, achieve the concentration ratio, and meet the system's operating parameters. The equipment involved in the internal circulation process includes the circulation pump 8, the instrumentation assembly 9 after the circulation pump, the STRO membrane module 10, the concentrate outlet pipeline 15, the internal circulation pipeline 16, and the internal circulation pressure reducing valve 17. The circulation pump 8 sends circulating water into the STRO membrane module 10. After circulation filtration, most of the concentrate returns to the circulation pump 8 via the concentrate outlet pipeline 15, the internal circulation pipeline 16, and the internal circulation pressure reducing valve 17 to continue participating in production.

[0085] Furthermore, another portion of the concentrate undergoes energy recovery via the energy recovery device 19 and is then discharged through the low-pressure concentrate discharge pipeline 22 and the concentrate exhaust valve 25. The pipelines or equipment involved in the energy recovery process include the high-pressure concentrate inlet pipeline 18, the energy recovery device 19, the high-pressure raw material outlet pipeline 20, the low-pressure raw material inlet pipeline 21, and the low-pressure concentrate discharge pipeline 22. A portion of the concentrate passing through the concentrate outlet pipeline 15 enters the high-pressure concentrate inlet pipeline 18. After passing through the energy recovery device 19, the high-pressure concentrate undergoes energy conversion. The converted low-pressure concentrate is then discharged through the low-pressure concentrate discharge pipeline 22 and the concentrate exhaust valve 25. During the energy conversion process, the low-pressure raw material enters the circulation pump 8 via the low-pressure raw material inlet pipeline 21, is pressurized, and then enters the circulation pump 8 via the high-pressure raw material outlet pipeline 20.

[0086] It should be noted that the concentrate from the STRO membrane module 10 first enters the concentrate outlet pipeline 15. The concentrate outlet pipeline 15 is connected to the internal circulation pressure reducing valve 17 via the internal circulation pipeline 16. The concentrate outlet pipeline 15 is connected to the first inlet of the energy recovery device 19 via the high-pressure concentrate inlet pipeline 18. The first outlet of the energy recovery device 19 is connected to the low-pressure concentrate outlet pipeline 22. The concentrate outlet pipeline 15 is also connected to the low-pressure concentrate outlet pipeline 22 via the pressure regulating valve 23.

[0087] The control system is connected to the raw water booster pump 1, plunger pump 5, circulation pump 8, product water pneumatic valve 14, internal circulation pressure reducing valve 17, concentrated liquid external venting pneumatic valve 25, product water end cleaning liquid return pneumatic valve 27, concentrated liquid end cleaning liquid return pneumatic valve 28, flushing pneumatic valve 29, product water end wastewater external venting pneumatic valve 30, concentrated liquid end wastewater external venting pneumatic valve 31, and cleaning high-pressure pneumatic valve 33. The control system can control the start and stop of each pump and the opening and closing of each valve to meet the system requirements.

[0088] This utility model also includes a chemical cleaning pipeline 26. The plunger pump 5 and the circulation pump 8 are connected via a third pipeline 103. The chemical cleaning pipeline 26 is connected to the third pipeline 103 via a high-pressure cleaning pneumatic valve 33. A small portion of the cleaning solution from the STRO membrane module 10 enters the cleaning tank via a fifth pipeline 105 and a cleaning solution return pneumatic valve 27 at the permeate end. Most of the cleaning solution from the STRO membrane module 10 enters the cleaning tank via a concentrate outlet pipeline 15, a pressure regulating valve 23, and a concentrate end cleaning solution return pneumatic valve 28. The above configuration can complete the chemical cleaning process. The chemical cleaning process and the raw liquid filtration process share some pipelines and equipment. The chemical cleaning pipeline 26 is equipped with a high-pressure cleaning pneumatic valve 33, which is connected to the raw liquid filtration pipeline. After passing through the circulation pump 8, the STRO membrane module 10, and the internal circulation pipeline 16, the product water end returns to the cleaning tank through the cleaning liquid return pneumatic valve 27. The concentrate end returns to the cleaning tank through the concentrate outlet membrane pipeline 15, the high-pressure concentrate inlet pipeline 18, the energy recovery device 19, the low-pressure concentrate outlet pipeline 22, and the concentrate end cleaning liquid return pneumatic valve 28.

[0089] This utility model also includes a flushing pneumatic valve 29, used to complete the shutdown flushing process. The flushing process shares some pipelines and equipment with the raw liquid filtration process. The flushing pneumatic valve 29 is installed on the sixth pipeline 106. The raw water booster pump 1 is connected to the precision filter 3 through the first pipeline 101, and the sixth pipeline 106 is connected to the first pipeline 101. After the flushing water enters from the sixth pipeline 106, it flushes the STRO membrane module 10. A small portion of the flushing water enters the wastewater tank through the fourth pipeline 104, the fifth pipeline 105, and the wastewater exhaust pneumatic valve 30 at the product water end. Most of the flushing water is discharged into the wastewater tank through the concentrate outlet pipeline 15, the high-pressure concentrate inlet pipeline 18, the pressure regulating valve 23, and the wastewater exhaust pneumatic valve 31 at the concentrate end.

[0090] Specifically, the precision filter 3 is connected to the plunger pump 5 through the second pipeline 102. Part of the low-pressure raw liquid in the second pipeline 102 enters the second inlet of the energy recovery device 19 after being pressurized through the low-pressure raw liquid inlet pipeline 21. It then exits from the second outlet of the energy recovery device 19 and enters the inlet of the circulation pump 8 after passing through the high-pressure raw liquid outlet pipeline 20, thereby realizing the recovery and utilization of energy.

[0091] The raw water booster pump 1 is connected to the precision filter 3 via the first pipeline 101. The dosing equipment is connected to the first pipeline 101 via the dosing pipeline 32. The first pipeline 101 is also equipped with an inlet pump post-instrument assembly 2, and the fifth pipeline 105 is equipped with a product water instrument assembly 12. The inlet pump post-instrument assembly 2 includes multiple detection components, such as a flow meter, conductivity meter, pressure transmitter, pressure gauge, and temperature sensor. The product water instrument assembly 12 also includes multiple detection components, such as a flow meter, pressure transmitter, pressure gauge, and temperature sensor.

[0092] This utility model also provides a chemical cleaning method for a reverse osmosis treatment system, which includes the following steps:

[0093] Step 1: Open the cleaning high-pressure pneumatic valve 33, the internal circulation pressure reducing valve 17, the cleaning fluid return pneumatic valve 27 at the product water end, the pressure regulating valve 23, and the cleaning fluid return pneumatic valve 28 at the concentrate end.

[0094] Step 2: The chemical cleaning solution enters the STRO membrane module 10 through the chemical cleaning pipeline 26 and then enters through the circulation pump 8. The cleaning solution coming out of the STRO membrane module 10 first returns to the inlet of the circulation pump 8 through the internal circulation pipeline 16 and then re-enters the STRO membrane module 10 to achieve internal circulation cleaning.

[0095] Step 3: After the cleaning time is reached, a small portion of the cleaning solution from the STRO membrane module 10 returns to the cleaning tank through the cleaning solution return pneumatic valve 27, while the majority of the cleaning solution from the STRO membrane module 10 returns to the cleaning tank through the concentrate outlet pipeline 15, the pressure regulating valve 23, and the concentrate end cleaning solution return pneumatic valve 28.

[0096] This utility model also provides a shutdown flushing method for a reverse osmosis treatment system, which includes the following steps:

[0097] S1: Open the flushing pneumatic valve 29, the internal circulation pressure reducing valve 17, the wastewater external venting pneumatic valve 30 at the product water end, the pressure regulating valve 23, the wastewater external venting pneumatic valve 31 at the concentrate end;

[0098] S2: The flushing water enters the STRO membrane module 10 through the flushing pneumatic valve 29, precision filter 3, plunger pump 5, and circulation pump 8 for flushing. The flushing liquid coming out of the STRO membrane module 10 first returns to the inlet of the circulation pump 8 through the internal circulation pipeline 16 and then re-enters the STRO membrane module 10 to achieve internal circulation flushing.

[0099] S3: After the cleaning reaches the set time, a small portion of the flushing water from the STRO membrane module 10 is discharged into the wastewater tank through the wastewater exhaust valve 30 at the product water end; most of the flushing water from the STRO membrane module 10 is discharged into the wastewater tank through the concentrate outlet pipeline 15, the pressure regulating valve 23, and the concentrate end wastewater exhaust valve 31.

[0100] This utility model also provides an energy recovery method for a reverse osmosis treatment system. The energy recovery method using a reverse osmosis treatment system is as follows:

[0101] Part of the concentrate from the concentrate outlet pipe 15 enters the energy recovery device 19 through the high-pressure concentrate inlet pipe 18 for energy conversion. The high-pressure concentrate drives the turbine at one end of the energy recovery device 19 to rotate, converting high-pressure water energy into mechanical energy. The rotating mechanical energy then drives the turbine at the other end of the energy recovery device 19 to rotate and draw in the raw liquid. The raw liquid enters the second inlet of the energy recovery device 19 through the low-pressure raw liquid inlet pipe 21, is pressurized, and then exits from the second outlet of the energy recovery device 19, thus completing the energy conversion.

[0102] This utility model also provides a method for filtering the feed solution in a reverse osmosis treatment system, which includes the following steps:

[0103] M1: Open the pneumatic valve 14 for product water, the internal circulation pressure reducing valve 17, the pressure regulating valve 23, and the concentrated liquid external exhaust pneumatic valve 25;

[0104] M2: Start the raw water booster pump 1 to send the raw water through the precision filter 3, the plunger pump 5 and the circulation pump 8 to the STRO membrane module 10. The water required by the STRO membrane module 10 includes a portion of the concentrate that flows back to the inlet of the circulation pump 8 at the outlet of the STRO membrane module 10.

[0105] M3: The STRO membrane module 10 separates the raw water under high pressure. The effluent from the STRO membrane module 10 is divided into two parts: concentrate and permeate. The permeate after the permeate from each STRO membrane module 10 is collected is discharged through the fifth pipeline 105 and the permeate pneumatic valve 14. The concentrate from each STRO membrane module 10 is collected and discharged through the concentrate outlet pipeline 15. Part of the discharged concentrate enters the internal circulation process and returns to the STRO membrane module 10 to participate in production, while the other part enters the energy recovery device 19 to participate in energy conversion before being discharged.

[0106] In addition to the above-mentioned process flow and main components, this utility model also includes numerous instrumentation components, including instrumentation component 2 after the inlet pump, instrumentation component 4 after the filter, instrumentation component 7 after the high-pressure pump, instrumentation component 9 after the circulation pump, product water float flowmeter 11, product water instrumentation component 12, concentrate instrumentation component 24, concentrate membrane outlet instrumentation component 34, and scale inhibitor dosing point 35. The plunger pump 5 and circulation pump 8 are preferably variable frequency pumps. In practical applications, the number of plunger pump 5 and STRO membrane module 10 can be increased or decreased according to design requirements.

[0107] like Figure 1 As shown, the process principle of the ultra-high pressure reverse osmosis treatment system in this utility model is as follows:

[0108] Raw water filtration process: When the reverse osmosis system starts operating, the permeate pneumatic valve 14, internal circulation pressure reducing valve 17, pressure regulating valve 23, and concentrate external venting pneumatic valve 25 are open, while other valves are closed. The raw water booster pump 1 delivers raw water to the precision filter 3. The raw water booster pump 1 can provide the designed flow rate and a pressure of 3-5 bar. This pressure, in addition to overcoming pressure loss in the pipeline and precision filter 3, also provides a certain pressure for the downstream plunger pump 5. The precision filter 3 removes fine solid particles from the raw water to prevent mechanical damage to the downstream plunger pump 5 and membrane modules. A scale inhibitor dosing point 35 is also provided between the raw water booster pump 1 and the precision filter 3 to prevent scaling on the membrane modules. A set of plunger pumps 5 is connected after the precision filter 3. Plunger pumps 5 have three functions: first, to provide a stable feed water flow rate to the system; second, to provide the required osmotic pressure for the system's permeate; and third, each plunger pump 5 is followed by a safety valve 6 with a set pressure value, for example, 110 bar. Safety valves 6 are used to release pressure in time when the system pressure is too high to protect the system. The number of plunger pumps 5 is determined according to the system design parameters. The plunger pumps 5 are controlled by variable frequency motors, which can flexibly control the feed water flow rate and operating pressure according to the actual operating conditions of the system, thereby controlling the permeate rate. The raw water after passing through plunger pumps 5 enters circulation pump 8. The main function of circulation pump 8 is to directly send the high-pressure, high-flow-rate raw water into the STRO membrane module 10. Since the flow rate provided by plunger pumps 5 does not meet the water volume required by the membrane module, a portion of the concentrate from the membrane module outlet is returned to the inlet of circulation pump 8 through circulation pump 8 to ensure sufficient flow and velocity on the membrane surface, achieving the reasonable design flux and avoiding membrane fouling. Simultaneously, by controlling the flow rate of the circulating pump 8 via a frequency converter, the system can be kept in optimal operating conditions, avoiding damage to the membrane caused by excessive pressure and flow rate. STRO membrane modules 10 preferably use 5-6 modules connected in series, with multiple modules connected in parallel depending on the processing capacity. The membrane elements separate the raw water under high pressure. The effluent from the STRO membrane module 10 is divided into concentrate and permeate. The permeate from each membrane module is collected and discharged through the fifth pipeline 105 and the permeate pneumatic valve 14. The permeate float flowmeter 11 monitors the permeate from each membrane module, facilitating observation of permeate volume and color difference. The concentrate from each membrane module is collected and discharged through the concentrate outlet pipeline 15. Part of the discharged concentrate enters the internal circulation process for production, and the other part enters the energy recovery process for energy conversion.

[0109] Internal circulation process: The internal circulation process is added because the water quality is very poor, and the concentration ratio can only be achieved by increasing the number of membrane elements and reducing the design flux. This requires a larger permeate flow rate to meet the design parameters. Therefore, most of the concentrate discharged from the membrane outlet pipeline 15 is sucked back into the STRO membrane module 10 through the internal circulation pipeline 16 and the internal circulation pressure reducing valve 17 to continue participating in production. The main function of the internal circulation pressure reducing valve 17 is to automatically adjust the opening to control the pressure before and after the valve, ensuring that the pressure before the internal circulation pressure reducing valve 17 is slightly higher than the pressure after the internal circulation pressure reducing valve 17. That is, the pressure in the high-pressure concentrate inlet pipeline 18 is higher than the pressure in the high-pressure feed liquid outlet pipeline 20. This pressure is generally in the range of 0-0.6 bar. This pressure difference is crucial to ensure the normal operation of the energy recovery system. When the circulation pump 8 also starts, the pressure regulating valve 23 is gradually closed to pressurize the system, causing the pressure to rise and drive the energy recovery device to operate.

[0110] Energy recovery process: The energy recovery process includes a high-pressure concentrate inlet pipe 18, an energy recovery device 19, a high-pressure raw liquid outlet pipe 20, a low-pressure raw liquid inlet pipe 21, and a low-pressure concentrate outlet pipe 22. Another part of the concentrate that has passed through the concentrate outlet pipe 15 enters the energy recovery device 19 through the high-pressure concentrate inlet pipe 18 for energy conversion. The amount of this concentrate is equal to the raw water inlet flow rate minus the designed product water flow rate. The high-pressure concentrate drives the energy recovery device 19 to rotate, and the high-pressure water energy is converted into mechanical energy. The rotating mechanical energy then drives the turbine at the other end to draw in the raw liquid. The raw liquid enters the energy recovery device 19 through the low-pressure raw liquid inlet pipe 21, continuously increasing the pressure of the raw liquid until the designed inlet water pressure. This pressure value is basically equivalent to the pressure after the plunger pump 5, and the energy conversion is also completed. The converted high-pressure raw liquid is drawn back into the STRO membrane module 10 by the circulation pump 8 to participate in production. It can be seen that there are three groups of water in the circulation pump 8 and the STRO membrane module 10: the water from the high-pressure plunger pump 5, the water after energy conversion, and a portion of the concentrated liquid after filtration.

[0111] One of the innovations of the ultra-high pressure reverse osmosis treatment system is energy saving, and its specific energy-saving effects are significant. The concentration ratio of the three-stage concentration process for mine water is generally 2 times, meaning a water production rate of around 50%. Assuming the system's influent (after plunger pump 5) is 2 parts, the product water is 1 part, and the concentrate is 1 part, since the energy recovery device has a conversion efficiency of over 97%, and considering process losses, the conversion efficiency of the 1 part concentrate is approximately 95%. This means that of the 2 parts of influent, 0.95 parts are saved through energy conversion, and 1.05 parts represent the actual work required by plunger pump 5. Therefore, this energy-saving process saves 47.5% of energy compared to a non-energy-saving design, resulting in considerable annual energy savings.

[0112] An inlet pump post-instrument assembly 2 is installed on the pipeline between the raw water booster pump 1 and the precision filter 3. A flow sensor monitors the inlet water flow rate, a conductivity meter monitors the inlet water conductivity, a pressure sensor monitors the pressure after the inlet pump, and a temperature sensor monitors the inlet water temperature in real time. A filter post-instrument assembly 4 is installed between the precision filter 3 and the plunger pump 5: a pressure sensor monitors the pressure before the plunger pump 5 to ensure the pressure meets operating requirements; simultaneously, it works with the pressure sensor in the inlet pump post-instrument assembly 2 to monitor the pressure difference of the precision filter 3. Excessive pressure difference prompts for filter element replacement. High-pressure pump post-instrument assemblies 7 and 9 are installed after the plunger pump 5 and circulation pump 8, respectively: these monitor the pressure values ​​at the pump terminals. The difference between the two is the membrane pressure difference, used to determine if the membrane is clogged or requires chemical cleaning, effectively protecting the normal operation of the system. A concentrate outlet membrane instrumentation assembly 34 is installed before the energy recovery device 19. This assembly monitors the concentrate outlet membrane pressure, and the pressure difference between it and the pressure of the instrumentation assembly 7 after the high-pressure pump is controlled between 0-0.6 bar to ensure stable operation of the energy recovery process. A product water instrumentation assembly 12 is installed at the product water end. The flow sensor in the product water instrumentation assembly 12 monitors the product water flow rate, the conductivity meter monitors the product water conductivity, and the pressure sensor monitors the product water pressure. A concentrate outlet instrumentation assembly 24 is installed on the low-pressure concentrate discharge pipeline 22. The float flow meter on the concentrate outlet instrumentation assembly 24 observes the concentrate flow rate, the conductivity meter monitors the concentrate conductivity, the pressure sensor monitors the concentrate discharge pressure, and the temperature sensor monitors the concentrate temperature in real time. This temperature is used for temperature protection during chemical cleaning, and the pH sensor is used for pH control during chemical cleaning.

[0113] Shutdown flushing process: When the system stops running, the internal system needs to be flushed clean. Industrial water or the system's product water can be used for flushing. The flushing process shares some pipelines and equipment with the feed filtration process. During shutdown flushing, the flushing pneumatic valve 29, internal circulation pressure reducing valve 17, product water wastewater venting pneumatic valve 30, pressure regulating valve 23, and concentrate wastewater venting pneumatic valve 31 are opened, while other valves are closed. The flushing water enters the STRO membrane module 10 for flushing through the flushing pneumatic valve 29, precision filter 3, plunger pump 5, and circulation pump 8. Since there is no increase in osmotic pressure, only a small amount of product water is discharged through the product water wastewater venting pneumatic valve 30, and most of the flushing water is discharged through the concentrate outlet pipeline 15, pressure regulating valve 23, and concentrate wastewater venting pneumatic valve 31.

[0114] Chemical Cleaning Process: Reverse osmosis systems require regular chemical cleaning. The purpose of cleaning is to remove organic matter and inorganic salts from the system, ensuring long-term stable operation and reducing malfunctions and damage. During chemical cleaning, the high-pressure pneumatic valve 33, internal circulation pressure reducing valve 17, product water end cleaning solution return pneumatic valve 27, pressure regulating valve 23, and concentrate end cleaning solution return pneumatic valve 28 are opened, while other valves are closed. The chemical cleaning process shares some piping and equipment with the feed filtration process. The chemical cleaning solution enters the STRO membrane module 10 through the chemical cleaning pipeline 26 and circulation pump 8, then returns to the circulation pump 8 through the internal circulation pipeline 16 and re-enters the STRO membrane module 10, continuously flushing the membrane surface for cleaning. A small portion of the product water returns to the cleaning tank through the cleaning solution return pneumatic valve 27, while most of the cleaning solution returns to the cleaning tank through the concentrate outlet membrane pipeline 15, pressure regulating valve 23, and concentrate end cleaning solution return pneumatic valve 28.

[0115] This invention presents a novel mine water treatment technology, primarily applied in the field of zero-discharge mine water resource utilization. Particularly in the tertiary membrane concentration stage, this technology can further halve the amount of coal mine concentrate, significantly reducing the subsequent treatment volume and scale. Correspondingly, the required treatment equipment and economic investment, such as evaporation and crystallization equipment, are also reduced considerably. This process system is designed for tertiary concentration processes, overcoming the challenges of higher TDS water quality and higher operating pressure. It further concentrates the secondary concentrate, achieving a TDS concentration exceeding 110,000 mg / L. The concentrate production is reduced by more than half compared to the secondary concentrate, saving a significant amount of usable water resources. This plays a crucial role in the resource utilization and zero-discharge of mine wastewater.

[0116] This invention is suitable for filtration of higher TDS and higher operating pressures, further concentrating the secondary concentrate. Simultaneously, it can operate stably and continuously under ultra-high pressure environments. The added internal circulation design ensures the system's filtration flux remains within the scientifically designed range, protecting the membrane element's durability and lifespan. The added energy recovery design achieves an energy recovery efficiency of over 97%, significantly reducing energy consumption. This invention uses a mesh-tube reverse osmosis membrane, resulting in a larger membrane area, smaller footprint, increased system anti-fouling capability, reduced energy consumption, and more convenient and simpler maintenance and repair.

[0117] The system in this invention is suitable for operating in environments with extremely poor water quality. The overall system flux needs to be controlled at around 10 LMH. A single pass of the feed solution through the membrane will severely exceed the system flux, potentially leading to system collapse. The internal circulation system design increases the circulation flow rate and reduces the membrane flux, ensuring stable and long-term system operation. Simultaneously, the single-stage process design ensures consistent water quality through the membrane, protecting the system's tolerance and lifespan. This invention utilizes an ultra-high pressure treatment process, which has relatively high energy consumption. Simply sacrificing energy for a halved concentrate yield does not demonstrate the economic advantages of the new process. Therefore, an energy recovery design is incorporated, achieving an energy recovery efficiency of over 97%, significantly reducing energy consumption. Furthermore, the use of a mesh-type reverse osmosis membrane increases the system's resistance to fouling, provides a larger membrane area, reduces the footprint, consumes less energy than DTRO membrane elements, and makes maintenance and repair more convenient and simple.

[0118] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application.

[0119] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this utility model. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A reverse osmosis treatment system, characterized by, The system comprises a raw water booster pump (1), a precision filter (3), a plunger pump (5), a circulating pump (8), a plurality of STRO membrane groups (10) arranged in parallel, an internal circulation pressure reducing valve (17), an energy recovery device (19), and a concentrated liquid discharge pneumatic valve (25). The raw water booster pump (1), the precision filter (3), the plunger pump (5), the circulating pump (8), and the STRO membrane groups (10) are sequentially connected. The water discharged from each STRO membrane group (10) is divided into concentrated liquid and permeate liquid. The permeate liquid sequentially passes through a fourth pipeline (104) and a fifth pipeline (105) and is discharged through a water production pneumatic valve (14). Part of the concentrated liquid discharged from the STRO membrane group (10) returns to the inlet of the circulating pump (8) through the internal circulation pressure reducing valve (17). Another part of the concentrated liquid is discharged through a low-pressure concentrated liquid discharge pipeline (22) and a concentrated liquid discharge pneumatic valve (25) after passing through the energy recovery device (19).

2. The reverse osmosis treatment system of claim 1, wherein, The concentrated liquid discharged from the STRO membrane group (10) first enters a concentrated liquid discharge membrane pipeline (15). The concentrated liquid discharge membrane pipeline (15) is connected to the internal circulation pressure reducing valve (17) through an internal circulation pipeline (16). The concentrated liquid discharge membrane pipeline (15) is connected to the first inlet of the energy recovery device (19) through a high-pressure concentrated liquid inlet pipeline (18). The first outlet of the energy recovery device (19) is connected to the low-pressure concentrated liquid discharge pipeline (22). The concentrated liquid discharge membrane pipeline (15) is also connected to the low-pressure concentrated liquid discharge pipeline (22) through a pressure regulating valve (23).

3. The reverse osmosis treatment system of claim 2, wherein, A chemical cleaning pipeline (26) is further included. The plunger pump (5) and the circulating pump (8) are connected through a third pipeline (103). The chemical cleaning pipeline (26) is connected to the third pipeline (103) through a cleaning high-pressure pneumatic valve (33). A small part of the cleaning liquid discharged from the STRO membrane group (10) enters a cleaning tank through the fifth pipeline (105) and a water production end cleaning liquid backflow pneumatic valve (27). Most of the cleaning liquid discharged from the STRO membrane group (10) enters the cleaning tank through the concentrated liquid discharge membrane pipeline (15), the pressure regulating valve (23), and a concentrated liquid end cleaning liquid backflow pneumatic valve (28).

4. The reverse osmosis treatment system of claim 2, wherein, A flushing pneumatic valve (29) is further included. The flushing pneumatic valve (29) is installed on a sixth pipeline (106). The raw water booster pump (1) is connected to the precision filter (3) through a first pipeline (101). The sixth pipeline (106) is connected to the first pipeline (101). Flushing water enters the sixth pipeline (106) to flush the STRO membrane group (10). A small part of the flushing water after flushing enters a waste water tank through the fourth pipeline (104), the fifth pipeline (105), and a water production end waste water discharge pneumatic valve (30). Most of the flushing water after flushing is discharged into the waste water tank through the concentrated liquid discharge membrane pipeline (15), the high-pressure concentrated liquid inlet pipeline (18), the pressure regulating valve (23), and a concentrated liquid end waste water discharge pneumatic valve (31).

5. The reverse osmosis treatment system of claim 2, wherein, The precision filter (3) is connected with the plunger pump (5) through a second pipeline (102), part of the low-pressure raw liquid in the second pipeline (102) enters the second inlet of the energy recovery device (19) after passing through a low-pressure raw liquid inlet pipeline (21), is pressurized, and then is discharged from the second outlet of the energy recovery device (19) and enters the inlet of the circulating pump (8) after passing through a high-pressure raw liquid outlet pipeline (20).

6. The reverse osmosis treatment system of claim 1, wherein, The raw water pressurizing pump (1) is connected with the precision filter (3) through a first pipeline (101), a dosing device is connected with the first pipeline (101) through a dosing pipeline (32), and a water inlet pump post-instrument assembly (2) is further arranged on the first pipeline (101), wherein the water inlet pump post-instrument assembly (2) comprises at least one detection component: a flow meter; a conductivity meter; a pressure transmitter; a pressure gauge; a temperature sensor. A water production instrument assembly (12) is arranged on the fifth pipeline (105), and the water production instrument assembly (12) comprises at least one detection component: a flow meter; a pressure transmitter; a pressure gauge; a temperature sensor.

7. The reverse osmosis treatment system of claim 1, wherein, A water production float flow meter (11) is arranged on the outlet pipeline of each group of STRO membrane groups (10).

8. The reverse osmosis treatment system of claim 1, wherein, Frequency converters are arranged on the motors of the plunger pump (5) and the circulating pump (8).

9. The reverse osmosis treatment system of claim 4, wherein, A scale inhibitor dosing point (35) is arranged on the first pipeline (101).

10. The reverse osmosis treatment system of claim 1, wherein, A safety valve (6) is arranged on the outlet pipeline of the plunger pump (5).

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