Energy recovery system and method

Abstract

The invention discloses an energy recovery system and method, and relates to the technical field of seawater desalination energy recovery, the energy recovery system comprises a rotary energy recovery device unit, a reciprocating switching type energy recovery device unit, a water hydraulic control unit and a testing and monitoring unit; the rotary energy recovery device unit and the reciprocating switching type energy recovery device unit are connected in parallel through a high-pressure pipeline and a low-pressure pipeline to form a pressure energy transmission loop, the water hydraulic control unit is arranged at a key node of the loop, and the fluid distribution proportion between the two device units is dynamically adjusted through a cartridge valve group; the testing and monitoring unit collects system pressure, flow and rotating speed parameters and controls the water hydraulic control unit to act through feedback signals, and cooperative operation of the rotary type energy recovery device unit and the reciprocating switching type energy recovery device unit is achieved. The efficient energy recovery device has the effect of efficient energy recovery under different flow working conditions.

Description

Technical Field

[0001] This invention relates to the technical field of energy recovery in seawater desalination, and in particular to an energy recovery system and method. Background Technology

[0002] Energy is a core resource for human survival and social development. With population growth, economic expansion, and improved living standards, global energy consumption continues to rise. my country's energy utilization rate is only around 40%, far below international advanced levels. Energy waste not only increases production costs but also exacerbates environmental pollution. In industrial production, large amounts of high-pressure fluids are depressurized through pressure reducing valves or directly discharged, resulting in the ineffective utilization of their inherent pressure energy and causing serious energy losses.

[0003] With the increasing scarcity of global freshwater resources, seawater desalination has become one of the important means to solve the water supply problem in coastal areas. The mainstream seawater desalination technology at present is reverse osmosis. Its basic principle is to apply a pressure higher than the osmotic pressure of seawater (usually 5.5 to 6.9 MPa) to allow freshwater molecules in seawater to pass through a semi-permeable membrane into the product water side, while salt and other impurities are retained on the concentrate side and discharged.

[0004] However, during this process, approximately 40% to 50% of the feed seawater is discharged as high-pressure concentrated brine. This liquid still retains pressure close to that at the inlet. If it is released directly through a pressure reducing valve, it will result in a significant waste of energy. It is estimated that over 50% of the energy consumed in producing each ton of freshwater is used by high-pressure pumps. Therefore, efficiently recovering this pressure is crucial for improving system energy efficiency.

[0005] Current energy recovery technologies in the seawater desalination field traditionally rely on mechanical equipment such as turbines and hydraulic motors. In recent years, rotary pressure exchangers have become mainstream due to their compact structure and high recovery efficiency. The core idea of ​​these technologies is to achieve pressure transfer between high-pressure and low-pressure fluids through a single type of energy recovery device. Some imported rotary devices can achieve energy recovery efficiencies of over 94%.

[0006] However, existing technologies have significant drawbacks. Most directly, single rotary devices are poorly adaptable to fluctuations in system flow, and are prone to a sharp drop in energy recovery efficiency. Traditional mechanical equipment is large in size and complex to maintain, while imported rotary devices suffer from high noise, rotor jamming, high maintenance costs, and reliance on imported core technologies. At the same time, the lack of a precise fluid distribution and regulation mechanism and a real-time monitoring and feedback system results in poor device coordination, making it difficult to further improve the overall energy recovery efficiency. Mixing rate and leakage are poorly controlled, and it is impossible to achieve efficient energy recovery under different flow conditions. Summary of the Invention

[0007] This application provides an energy recovery system and method, which achieves efficient energy recovery under different flow conditions.

[0008] This application provides an energy recovery system and method, which adopts the following technical solution:

[0009] An energy recovery system and method are disclosed, comprising a rotary energy recovery unit, a reciprocating switching energy recovery unit, a hydraulic control unit, and a testing and monitoring unit. The rotary energy recovery unit and the reciprocating switching energy recovery unit are connected in parallel via high-pressure and low-pressure pipelines to form a pressure energy transmission loop. The hydraulic control unit is located at a key node of the loop and dynamically adjusts the fluid distribution ratio between the two units through a cartridge valve assembly. The testing and monitoring unit collects system pressure, flow rate, and rotation speed parameters and controls the hydraulic control unit via feedback signals to achieve coordinated operation of the rotary energy recovery unit and the reciprocating switching energy recovery unit.

[0010] Preferably, the rotary energy recovery device unit includes a rotor, an end cover, a sleeve, and a sealing assembly. The rotor is disposed in the closed space formed by the end cover and the sleeve. An inclined flow channel is provided inside the end cover, and an axial flow channel is provided on the outer wall of the rotor. The sealing assembly is distributed at the mating position between the rotor, the end cover, and the sleeve.

[0011] Preferably, the end cap is made of corrosion-resistant metal material, the inclination angle of the inclined flow channel inside the end cap is adjustable and has at least two different working angles, and the rotor adopts an integral molding structure of high-hardness ceramic material.

[0012] Preferably, the sealing assembly includes a static sealing structure and a dynamic sealing structure. The static sealing structure uses a rubber sealing ring, and the dynamic sealing structure uses a combination sealing structure of a composite material friction ring and an elastomer.

[0013] Preferably, the reciprocating switching energy recovery device unit includes a hydraulic cylinder, a reciprocating switcher, and a check valve. The hydraulic cylinder has a high-pressure chamber and a low-pressure chamber at its two ends, respectively. The reciprocating switcher drives the valve plate to reciprocate between the two ends of the hydraulic cylinder through a power actuator to achieve switching of the working fluid flow direction.

[0014] Preferably, the reciprocating switch includes a valve body and a hydraulic actuator. The valve body is provided with mutually isolated high-pressure flow channels and low-pressure flow channels. The hydraulic actuator synchronously controls the opening and closing states of multiple sealing valve plates in the valve body through a linkage mechanism.

[0015] Preferably, the hydraulic control unit includes a pilot control valve assembly, which adopts a cartridge structure with a conical valve core and a flexible seal. The valve assembly adjusts the valve opening by balancing the pressure difference and the spring force.

[0016] Preferably, the testing and monitoring unit includes a multi-parameter sensor network and a distributed data processing module. The sensor network includes a pressure sensor, a flow sensor, and a speed sensor. The data processing module uses a programmable logic controller to realize real-time parameter acquisition and control command output.

[0017] Preferably, the system also includes a raw seawater pretreatment module and a concentrated brine buffer module. The pretreatment module is connected in series in the low-pressure seawater inlet pipeline, and the buffer module is connected in parallel in the high-pressure concentrated brine outlet pipeline. Both modules are equipped with pressure stabilizing and regulating devices.

[0018] Preferably, a seawater desalination energy recovery method, based on the above-mentioned recovery system, includes the following steps: high-pressure concentrated brine and low-pressure raw seawater are alternately input into a rotary energy recovery unit for direct pressure transmission; when the system flow fluctuation exceeds a threshold, a reciprocating switching energy recovery unit is activated for pressure increase and decrease cycles; a hydraulic control unit dynamically adjusts the load distribution ratio of each device according to real-time pressure parameters; and a testing and monitoring unit continuously monitors the mixing rate and leakage indicators and triggers parameter adaptive correction.

[0019] In summary, this application has the following beneficial effects:

[0020] 1. To address the issues of poor adaptability to flow fluctuations and unstable energy recovery efficiency of single devices, and to further optimize the system's adaptability to different operating conditions, this invention also incorporates a dual-unit structure with rotary and reciprocating switching energy recovery devices connected in parallel. A pressure energy transmission loop is formed through high-pressure and low-pressure pipelines, enabling efficient energy recovery under varying flow conditions. During normal flow conditions, the high basic efficiency of the rotary device is relied upon; when flow fluctuations exceed a threshold, the reciprocating switching device activates to supplement energy, significantly improving the overall energy efficiency and stability of the system.

[0021] 2. In order to solve the problems of the inability to dynamically adjust the fluid distribution ratio and the poor effect of device coordination, and to further optimize the load distribution accuracy, this invention also sets up a water-hydraulic control unit located at the key node of the loop. It adopts a cartridge valve group structure to achieve the effect of accurately adjusting the fluid distribution ratio between the two device units according to the real-time operating conditions of the system, avoiding overload or inefficient operation of a single device, and ensuring that the energy recovery process is always in the optimal state.

[0022] 3. To address the lack of real-time monitoring and adaptive correction, and the uncontrolled operation of parameters, and to further optimize the system's control precision, this invention also includes a test and monitoring unit comprising a multi-parameter sensor network and a distributed data processing module. This unit enables real-time acquisition of core parameters such as pressure, flow rate, and rotational speed, drives the hydraulic control unit through feedback signals, and simultaneously monitors the mixing rate and leakage, triggering adaptive correction to ensure stable and reliable system operation.

[0023] 4. To address the issues of impurities in raw seawater affecting equipment lifespan and pressure fluctuations in concentrated brine interfering with energy recovery, and to further optimize the system's operating environment, this invention also includes a raw seawater pretreatment module and a concentrated brine buffer module. These are connected in series in the low-pressure inlet pipeline and in parallel in the high-pressure outlet pipeline, respectively, and both are equipped with pressure stabilizing devices. This achieves the effects of purifying the incoming water quality, stabilizing the concentrated brine pressure, reducing equipment scaling and leakage risks, and extending maintenance cycles. Attached Figure Description

[0024] Figure 1 This is an overall flowchart of the energy recovery system in this embodiment;

[0025] Figure 2 This is a flowchart of the rotary energy recovery device unit in this embodiment;

[0026] Figure 3 This is a flowchart of the reciprocating switching energy recovery device unit in this embodiment;

[0027] Figure 4 This is a flowchart of the water hydraulic control unit in this embodiment; Detailed Implementation

[0028] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0029] Example

[0030] This invention discloses an energy recovery system and method, such as Figure 1 As shown, it includes a rotary energy recovery unit, a reciprocating switching energy recovery unit, a hydraulic control unit, a testing and monitoring unit, and an auxiliary unit. The units work together to achieve efficient recovery and utilization of pressure energy.

[0031] like Figure 1 and Figure 2As shown, specifically, the rotary energy recovery unit is the core energy conversion component of the system, used to achieve direct pressure energy transfer between high-pressure concentrated brine and low-pressure raw seawater. Its structure includes a rotor, end caps, sleeves, and sealing components. The rotor, located in the enclosed space formed by the sleeves and end caps, obtains driving torque and rotates due to the impact of water in the inclined flow channel of the end caps, without the need for other external driving forces.

[0032] Specifically, the rotor is made of corundum ceramic material, with an outer diameter of 190mm, an axial length of 190mm, an outer wall thickness of 10mm, and a flow channel wall thickness of 5mm. The rotor has multiple axial flow channels with optimized end-face shapes to improve internal flow patterns and reduce mixing. The rotor material possesses excellent corrosion resistance, wear resistance, and mechanical strength, enabling it to withstand the high-pressure and highly corrosive environment of seawater desalination.

[0033] The end caps used to house the rotor include high-pressure and low-pressure end caps, made of 316L stainless steel. The end caps feature internal inclined flow channels with an adjustable angle between 6° and 32°. By optimizing the flow channel angle, a stable driving torque can be provided to the rotor, enabling self-driven rotation without additional power input. The end face clearance between the end caps and the rotor is controlled at 30μm, and the radial clearance at 35μm, ensuring sealing performance while reducing frictional losses.

[0034] The sleeve is made of 316L stainless steel and is located on the outside of the rotor. It is used to wrap the rotor and form a closed working cavity. The inner wall of the sleeve is precision machined to ensure the fit accuracy with the rotor and reduce leakage.

[0035] The sealing assembly includes O-rings and a combination seal. The O-rings are made of nitrile rubber (NBR) and are used for static sealing. The combination seal consists of a PE friction ring and a nitrile rubber elastomer and is used for dynamic sealing between the valve sleeve and the valve core. It can effectively prevent seawater leakage and reduce frictional resistance.

[0036] The working principle of this rotary energy recovery device is as follows: After the high-pressure concentrated brine enters the high-pressure side of the device, it is guided by the inclined flow channel of the end cap, forming a fluid impact force along the flow channel direction. This impact force generates a driving torque on the rotor, causing the rotor to rotate at high speed around its own axis. Simultaneously, the high-pressure concentrated brine and the low-pressure raw seawater come into direct contact in the axial flow channel of the rotor. Due to the pressure difference and momentum transfer of the fluids, the pressure energy of the high-pressure concentrated brine is converted into the pressure energy of the low-pressure raw seawater, thus increasing the pressure of the raw seawater. The rotation of the rotor enables continuous input and output of high-pressure concentrated brine and low-pressure raw seawater, avoiding energy loss caused by fluid mixing. By optimizing the rotor flow channel shape and the end cap inclination angle, the energy recovery efficiency can reach over 94%, with the mixing rate controlled at 3%-5%.

[0037] like Figure 1 and Figure 3 As shown, the reciprocating switching energy recovery unit serves as a supplementary energy recovery module to further improve the system's energy recovery efficiency and operational stability. It includes a hydraulic cylinder, a reciprocating switch, and a check valve. During the pressurization stroke of ERD #1: High-pressure brine enters ERD #1 through the switch, pressurizing the low-pressure seawater already filling the hydraulic cylinder, thus completing the pressure energy exchange. The pressurized seawater, after compensating for the pressure drop of the high-pressure brine during the membrane module and energy exchange process via a booster pump, mixes with the high-pressure seawater pressurized by the high-pressure pump and enters the theoretically defined membrane module. Simultaneously, ERD #2 undergoes a depressurization stroke: the low-pressure seawater pushes the depressurized brine, which has completed pressure energy exchange, through the switch into the depressurization pipeline for discharge. When ERD #1 completes its pressurization stroke and ERD #2 completes its depressurization stroke, the switch's operating position changes, and the pressurization and depressurization strokes in the two hydraulic cylinders alternate.

[0038] Specifically, the hydraulic cylinder is made of stainless steel that is resistant to seawater corrosion. It is used to achieve indirect pressure transmission between high-pressure concentrated brine and low-pressure seawater. The hydraulic cylinder is designed to withstand a maximum working pressure of 6.9 MPa, ensuring safe operation.

[0039] The active actuator and core component of the reciprocating switch energy recovery device, its structure and operating characteristics directly determine the system stability of the energy recovery device.

[0040] The reciprocating switch consists of a hydraulic actuator and a valve body. The valve body comprises separate high-pressure and low-pressure chambers, four metal-sealed valve plates, and three connection ports. The hydraulic actuator is the power component of the switch, driving the valve plates inside the valve body to perform regular reciprocating motion, thus switching the switch's operating position and achieving sealing. The valve body is equipped with a high-pressure brine inlet, a pressure-relief brine outlet, and a hydraulic cylinder connection port. The high-pressure chamber inside the switch serves as the flow channel for high-pressure brine and is connected to the high-pressure brine inlet; the low-pressure chamber serves as the flow channel for pressure-relief brine and is connected to the pressure-relief brine outlet. The opening and closing of the high and low-pressure fluid flow channels inside the switch are achieved by the hydraulic actuator driving the reciprocating motion of the high and low-pressure valve plates.

[0041] The switcher is PLC controlled and can alternate between the pressurization and depressurization strokes. The switching frequency can be adjusted according to actual working conditions. The rated throughput of the switcher is ≥30m³ / h, the static internal leakage is <0.5m³ / h, and the maximum withstand pressure is 6.9MPa.

[0042] Check valves are installed in the pressurized seawater outlet and low-pressure seawater inlet pipelines to prevent fluid backflow and ensure the continuity and stability of system operation.

[0043] The working principle of this reciprocating switching energy recovery device unit is as follows: The device employs a piston structure, using a reciprocating switch to control the alternating flow of high-pressure concentrated brine and low-pressure seawater. When the high-pressure concentrated brine enters the high-pressure chamber of the hydraulic cylinder, it pushes the piston to compress the raw seawater in the low-pressure chamber, thus transferring pressure energy. When the piston reaches its end, the switch changes position, depressurizing the high-pressure chamber and allowing the low-pressure chamber to draw in new raw seawater, completing one working cycle. The coordinated operation of the reciprocating switch ensures the continuity of pressure energy recovery, achieving an energy recovery efficiency of over 97%, effectively compensating for the performance limitations of rotary energy recovery devices under low-flow conditions.

[0044] like Figure 1 and Figure 4 As shown, the water-hydraulic control unit is used to control the fluid flow direction, pressure and flow rate of the energy recovery system, including a water-hydraulic two-way cartridge valve, valve group and pilot control module.

[0045] The water-hydraulic two-way cartridge valve adopts a "cone valve core + soft seal" structure. It includes a valve core, valve seat, valve cover, valve spool, spring, and sealing ring. The valve spool is made of polyoxymethylene (POM), while the valve sleeve and cover are made of 316L stainless steel. The spring is made of constant elastic modulus alloy 3J1. The nominal diameter of the cartridge valve includes 25mm, 50mm, and 100mm, corresponding to rated flow rates of 4m³ / h, 16m³ / h, and 64m³ / h, respectively. The opening pressure is 0.3MPa, the pressure resistance is 10MPa, and the pressure loss is 0.35-0.95bar (at a flow velocity of 2-4m / s at the valve orifice).

[0046] The valve assembly consists of four hydraulic two-way cartridge valves, designed according to the functional requirements of the reverse osmosis seawater desalination energy recovery device for the concentrated brine switching valve, to realize the switching control between high-pressure concentrated brine and low-pressure seawater.

[0047] The working principle of this water-hydraulic control unit is as follows: The water-hydraulic two-way cartridge valve adopts a "cone valve core + soft seal" structure, utilizing the balance between the pilot control pressure and the pressure difference between the upper and lower chambers of the valve core to achieve valve opening and closing. When pressurized water flows through the pilot control port, the valve core closes under the action of pressure difference and spring force, cutting off the fluid passage; when the pilot control port is depressurized, the valve core opens under the action of pressure difference between the upper and lower chambers, allowing fluid to pass through. By adjusting the opening and closing state and degree of opening of the cartridge valve, precise control of system flow and pressure can be achieved, ensuring the coordinated operation of each energy recovery unit.

[0048] The pilot control module includes components such as an electromagnetic directional valve, a pressure sensor, and a flow sensor. It is used to control the opening and closing of the hydraulic two-way cartridge valve, regulate the system pressure and flow, and ensure that all units work together.

[0049] The testing and monitoring unit is used to monitor the system's operating parameters in real time. Its structure includes sensor components, a data acquisition and processing module, and a monitoring terminal. Specifically, it monitors parameters such as pressure, flow rate, temperature, rotational speed, leakage, and mixing rate, providing data support for system optimization and fault diagnosis.

[0050] The sensor assembly includes a pressure transmitter, an electromagnetic flow meter, a temperature sensor, and a speed sensor. The pressure transmitter has a measurement range of 0-8 MPa and an accuracy of ±0.1%; the electromagnetic flow meter has a measurement range of 30-90 m³ / h and an accuracy of ±0.5%; the speed sensor adopts a non-contact design, is suitable for speed measurement in aquatic environments, has a measurement range of 0-1500 r / min, and an accuracy of ±1 r / min.

[0051] The data acquisition and processing module uses a PLC as the core controller, with a data acquisition frequency of 12Hz. It can acquire measurement data from various sensors in real time and transmit it to the monitoring terminal via industrial Ethernet. The data processing module can filter, analyze, and store the acquired data, generating pressure-flow characteristic curves, efficiency characteristic curves, etc.

[0052] The monitoring terminal includes an industrial computer, a touch screen, and an alarm device. It can display the system's operating status and parameters in real time, issue an alarm signal when the parameters exceed the set range, and can switch between manual and automatic control modes.

[0053] The auxiliary units include a raw seawater pretreatment module, a concentrated brine buffer module, and a cooling module, which ensure the stable operation of the energy recovery system.

[0054] Specifically, the raw seawater pretreatment module includes components such as filters and softeners, which are used to remove suspended solids, impurities and some ions from the raw seawater, prevent scaling and clogging inside the system, and extend the service life of the equipment.

[0055] The concentrated brine buffer module includes components such as a concentrated brine storage tank and a pressure regulating valve, which are used to stabilize the pressure and flow rate of high-pressure concentrated brine and reduce the impact of pressure fluctuations on energy recovery efficiency.

[0056] The cooling module includes components such as cooling fans and cooling pipes, which are used to reduce the temperature of the fluid during system operation and prevent equipment performance degradation or damage due to excessive temperature.

[0057] The method based on the above energy recovery system, which is implemented using the above energy recovery system, includes the following steps:

[0058] S1. System Startup and Warm-up:

[0059] Check the connection status, sealing performance, and power supply of each component of the system to ensure that there are no leaks or loose parts in the equipment and that the electrical system is functioning properly.

[0060] Start the raw seawater pretreatment module to filter and soften the raw seawater to ensure that the influent water quality meets the system requirements (suspended solids content ≤10mg / L, hardness ≤50mg / L as CaCO3).

[0061] Start the low-pressure pump to inject the pretreated raw seawater into the system pipeline and expel the air in the pipeline; at the same time, start the cooling module to put the cooling system into working condition.

[0062] Gradually adjust the pressure regulating valve to slowly increase the system pressure to 1.0 MPa, maintain this pressure for 30 minutes to complete system preheating, and check the operating status of each component.

[0063] S2. Rotary energy recovery unit in operation:

[0064] Start the high-pressure pump to pressurize the pretreated raw seawater to 0.2MPa, and then transport it to the low-pressure side of the rotary energy recovery device through the low-pressure seawater inlet pipeline.

[0065] The high-pressure concentrated brine (pressure 5.5-6.0MPa) generated by the reverse osmosis seawater desalination system enters the high-pressure side of the rotary energy recovery device through the high-pressure brine inlet pipe. Under the action of the inclined flow channel of the end cap, the high-pressure concentrated brine drives the rotor to rotate, and at the same time transfers the pressure energy to the low-pressure raw seawater.

[0066] The rotor is driven by high-pressure concentrated brine to achieve self-rotation. The rotation speed is automatically adjusted according to the flow rate and pressure of the high-pressure concentrated brine. When the pressure of the high-pressure concentrated brine is 5MPa and the flow rate is 70m³ / h, the rotor speed is about 1200r / min.

[0067] The pressurized seawater (pressure increased to 5.4-5.9 MPa) is transported to the reverse osmosis membrane module through the pressurized seawater outlet pipeline for seawater desalination; the depressurized brine (pressure reduced to 0.19-0.21 MPa) is discharged through the depressurized brine outlet pipeline and enters the brine buffer module.

[0068] S3. Cooperative operation of reciprocating switching energy recovery device:

[0069] When the processing capacity of the rotary energy recovery device is insufficient or the system pressure fluctuates greatly, the reciprocating switching energy recovery device unit is started. The hydraulic drive of the reciprocating switch is controlled by the PLC to realize the reciprocating motion of the high-pressure valve plate and the low-pressure valve plate.

[0070] High-pressure concentrated brine enters the high-pressure chamber of the hydraulic cylinder through the high-pressure brine inlet of the reciprocating switch, pushing the piston of the hydraulic cylinder to move and pressurize the raw seawater in the low-pressure seawater chamber. The pressurized raw seawater then flows into the pressurized seawater outlet pipeline through the check valve.

[0071] When the piston of the hydraulic cylinder reaches the end of its stroke, the reciprocating switch automatically switches the working position, the high-pressure chamber is depressurized, and the low-pressure seawater chamber is re-injected with raw seawater, realizing the cyclical alternation of the pressurization stroke and the depressurization stroke, ensuring the continuous recovery of pressure energy.

[0072] Adjust the switching frequency of the reciprocating switcher (10-20 times / minute) to match the output pressure and flow rate of the reciprocating switching energy recovery device with that of the rotary energy recovery device, ensuring the stability of system operation.

[0073] S4. Water hydraulic control unit adjustment:

[0074] The hydraulic two-way cartridge valve automatically opens and closes under the action of the pilot control module based on the pressure and flow data collected by the testing and monitoring unit, thereby regulating the flow distribution of high-pressure concentrated brine and low-pressure seawater.

[0075] When the system pressure exceeds the set value (6.9MPa), the pressure sensor sends a signal, and the pilot control module controls the hydraulic two-way cartridge valve to partially open to relieve pressure. When the system pressure is lower than the set value, the cartridge valve opens fully to increase the fluid flow and increase the pressure.

[0076] By adjusting the opening degree of each cartridge valve in the valve group, the load distribution of the rotary energy recovery device and the reciprocating switching energy recovery device is controlled, ensuring the optimal overall energy recovery efficiency of the system.

[0077] S5. Monitoring and Optimization of Operating Parameters:

[0078] The testing and monitoring unit collects parameters such as high pressure inlet pressure, high pressure outlet pressure, low pressure inlet pressure, low pressure outlet pressure, high pressure flow rate, low pressure flow rate, rotor speed, mixing rate, and leakage in real time, and transmits them to the monitoring terminal.

[0079] The data processing module analyzes the collected parameters and calculates key indicators such as energy recovery efficiency and pressure loss rate. When the energy recovery efficiency is lower than 94% or the mixing rate is higher than 5%, it automatically adjusts parameters such as the end cap flow channel tilt angle and the reciprocating switch switching frequency to optimize the system operation.

[0080] Regularly perform statistical analysis on system operation data and generate operation reports to provide a basis for equipment maintenance and process optimization.

[0081] S6. System shutdown:

[0082] When a seawater desalination project is completed or requires maintenance, first shut down the high-pressure pump and stop the input of high-pressure concentrated brine.

[0083] Keep the low-pressure pump running and continue to introduce low-pressure seawater to flush the system pipelines and the inside of the energy recovery device, removing residual salt scale and impurities. The flushing time should be no less than 15 minutes.

[0084] Shut down the low-pressure pump and cooling module, disconnect the system power, inspect and maintain the equipment, and ensure normal startup next time.

[0085] It is worth noting that the calculation principle of energy recovery efficiency is as follows: The formula for calculating energy recovery efficiency η is:

[0086] η=(Qso×Pso-Qsi×Psi) / (Qbi×Pbi-Qbo×Pbo)×100%;

[0087] Where Qbi is the inlet flow rate of high-pressure concentrated brine, Pbi is the inlet pressure of high-pressure concentrated brine, Qbo is the outlet flow rate of high-pressure concentrated brine, Pbo is the outlet pressure of high-pressure concentrated brine, Qsi is the inlet flow rate of low-pressure feed seawater, Psi is the inlet pressure of low-pressure feed seawater, Qso is the outlet flow rate of pressurized seawater, and Pso is the outlet pressure of pressurized seawater. This formula reflects the energy recovery effect of the system by calculating the ratio of the effective energy recovered to the total energy input of high-pressure concentrated brine.

[0088] Working principle: The energy recovery system of this invention is based on the principle of direct pressure energy transmission. Through the coordinated operation of a rotary energy recovery device and a reciprocating switching energy recovery device, energy exchange between high-pressure concentrated brine and low-pressure raw seawater is realized.

[0089] Specifically, firstly, pretreatment preparation is completed before system startup. The raw seawater is filtered and softened by the pretreatment module to remove suspended solids and excess ions, ensuring that the influent water quality meets the equipment's operating requirements. At the same time, the concentrated brine buffer module enters standby mode to ensure stable pressure later. Subsequently, the system is officially started. Low-pressure raw seawater is transported to the low-pressure side of the rotary energy recovery unit through low-pressure pipelines, while high-pressure concentrated brine produced by reverse osmosis seawater desalination enters the high-pressure side of the unit through high-pressure pipelines. The two are in direct contact in the axial flow channel of the rotor, and the initial transfer of pressure energy is achieved through pressure difference and momentum transfer. The rotor rotates self-driven under the impact of high-pressure fluid without the need for additional power, ensuring the basic efficiency of energy recovery.

[0090] Next, the testing and monitoring unit collects system operating parameters in real time using pressure, flow, and speed sensors, and transmits the data to the distributed data processing module for analysis and processing by the programmable logic controller. When the system flow fluctuation is detected to be within the set threshold, the hydraulic control unit maintains the current fluid distribution ratio, and the rotary device unit continues to dominate energy recovery. When the flow fluctuation exceeds the threshold, the data processing module immediately sends a feedback signal, triggering the reciprocating switching energy recovery device unit to start. Subsequently, the reciprocating switching device controls the valve plate to reciprocate through a hydraulically driven actuator, realizing the alternating switching between the high-pressure chamber and the low-pressure chamber at both ends of the hydraulic cylinder. High-pressure concentrated brine enters the high-pressure chamber, pushing the piston to pressurize the low-pressure seawater, completing the pressure increase and decrease cycle, and compensating for the performance deficiencies of the rotary device under fluctuating conditions.

[0091] Meanwhile, the hydraulic control unit dynamically adjusts the fluid distribution ratio between the two units through cartridge valve assemblies based on real-time pressure parameters fed back by the testing and monitoring unit. Utilizing the cooperation of the cone valve core and flexible seals, it precisely controls the valve opening through the balance between pressure difference and spring force, ensuring reasonable load distribution between the two units and maximizing their synergistic efficiency. During this process, the testing and monitoring unit continuously monitors key indicators such as mixing rate and leakage. If any parameters deviate from the optimal range, it immediately triggers an adaptive correction command, adjusting parameters such as the end cap flow channel inclination angle and the switching frequency of the reciprocating switch to keep the mixing rate low and reduce energy loss.

[0092] Finally, the raw seawater, pressurized by energy recovery, is mixed with seawater pressurized by a high-pressure pump and then enters the reverse osmosis membrane module for desalination. The concentrated brine, after pressure relief, is discharged through a pressure relief pipeline and treated and discharged after pressure stabilization by a concentrated brine buffer module. Throughout the process, the pretreatment and buffer modules continuously function, the pressure stabilization device ensures stable inlet and outlet water pressures, and the sealing components prevent seawater leakage through a combination of static and dynamic seals. All units operate collaboratively under the overall control of the testing and monitoring unit, ultimately achieving efficient, stable, and low-loss energy recovery for seawater desalination.

[0093] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An energy recovery system, characterized in that, The system includes a rotary energy recovery unit, a reciprocating switching energy recovery unit, a hydraulic control unit, and a testing and monitoring unit. The rotary energy recovery unit and the reciprocating switching energy recovery unit are connected in parallel through high-pressure and low-pressure pipelines to form a pressure energy transmission loop. The hydraulic control unit is located at a key node of the loop and dynamically adjusts the fluid distribution ratio between the two units through cartridge valve groups. The testing and monitoring unit collects system pressure, flow rate, and speed parameters and controls the hydraulic control unit through feedback signals to achieve coordinated operation of the rotary energy recovery unit and the reciprocating switching energy recovery unit.

2. The energy recovery system according to claim 1, characterized in that, The rotary energy recovery device unit includes a rotor, an end cover, a sleeve, and a sealing assembly. The rotor is disposed in the closed space formed by the end cover and the sleeve. An inclined flow channel is provided inside the end cover, and an axial flow channel is provided on the outer wall of the rotor. The sealing assembly is distributed at the mating positions between the rotor, the end cover, and the sleeve.

3. The energy recovery system according to claim 2, characterized in that, The end cap is made of corrosion-resistant metal material, the inclination angle of the inclined flow channel inside the end cap is adjustable and has at least two different working angles, and the rotor adopts an integral molding structure of high-hardness ceramic material.

4. The energy recovery system according to claim 3, characterized in that, The sealing assembly includes a static sealing structure and a dynamic sealing structure. The static sealing structure uses a rubber sealing ring, and the dynamic sealing structure uses a combination sealing structure of a composite material friction ring and an elastomer.

5. The energy recovery system according to claim 1, characterized in that, The reciprocating switching energy recovery device unit includes a hydraulic cylinder, a reciprocating switcher, and a check valve. The hydraulic cylinder has a high-pressure chamber and a low-pressure chamber at its two ends, respectively. The reciprocating switcher drives the valve plate to reciprocate between the two ends of the hydraulic cylinder through a power actuator to achieve the switching of the working fluid flow direction.

6. The energy recovery system according to claim 5, characterized in that, The reciprocating switch includes a valve body and a hydraulic actuator. The valve body is provided with a high-pressure flow channel and a low-pressure flow channel that are isolated from each other. The hydraulic actuator synchronously controls the opening and closing state of multiple sealing valve plates in the valve body through a linkage mechanism.

7. The energy recovery system according to claim 1, characterized in that, The hydraulic control unit includes a pilot control valve assembly, which adopts a cartridge structure with a conical valve core and a flexible seal. The valve assembly adjusts the valve opening by balancing the pressure difference and the spring force.

8. The energy recovery system according to claim 1, characterized in that, The testing and monitoring unit includes a multi-parameter sensor network and a distributed data processing module. The sensor network includes a pressure sensor, a flow sensor, and a speed sensor. The data processing module uses a programmable logic controller to realize real-time parameter acquisition and control command output.

9. The energy recovery system according to claim 1, characterized in that, It also includes a raw seawater pretreatment module and a concentrated brine buffer module. The pretreatment module is connected in series in the low-pressure seawater inlet pipeline, and the buffer module is connected in parallel in the high-pressure concentrated brine outlet pipeline. Both are equipped with pressure stabilizing and regulating devices.

10. A method for energy recovery from seawater desalination, based on the recovery system described in any one of claims 1-9, characterized in that, Includes the following steps: High-pressure concentrated brine and low-pressure raw seawater are alternately fed into the rotary energy recovery unit for direct pressure transmission. When the system flow fluctuation exceeds the threshold, the reciprocating switching energy recovery unit is activated to perform pressure increase and decrease cycles. The hydraulic control unit dynamically adjusts the load distribution ratio of each device based on real-time pressure parameters; the testing and monitoring unit continuously monitors the mixing rate and leakage rate and triggers adaptive parameter correction.

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