Seawater desalination system and seawater desalination method

Abstract

The application belongs to the technical field of seawater treatment, and discloses a seawater desalination system and a seawater desalination method. The seawater desalination system comprises a first channel, a second channel, a plunger pump device, a pressure stabilizing device and a reverse osmosis device. The first channel is communicated with the second channel. The plunger pump device is movably arranged in the first channel. The pressure stabilizing device and the reverse osmosis device are both arranged in the second channel. The pressure stabilizing device comprises a piston, a stopper and an adjusting mechanism. The piston is elastically arranged in the second channel. The stopper is arranged in the second channel and located in the movement stroke interval of the piston. The adjusting mechanism acts on the piston and adjusts the distance between the piston and the stopper. The maximum compression stroke is reached when the piston moves to abut against the stopper. The seawater desalination system can ensure that the seawater pressure entering the reverse osmosis device is in a good stable state. The pressure range is controlled between the pressure that can be applied by the plunger pump device and the pressure that can be borne by the reverse osmosis device, thereby effectively avoiding damage to the reverse osmosis device.

Description

Technical Field

[0001] This invention belongs to the technical field of seawater treatment equipment, specifically relating to a seawater desalination system and a seawater desalination method. Background Technology

[0002] With the increasing population and environmental degradation, freshwater resources sufficient to meet human needs are dwindling. Seawater desalination technology is one way to address the freshwater crisis. However, high energy consumption, water production costs, and the need to treat concentrated brine as a byproduct severely restrict the large-scale industrial development of seawater desalination. Although the cost of seawater desalination in my country has shown a downward trend in recent years, the overall cost remains relatively high. Compared to other seawater desalination technologies, reverse osmosis has lower production costs and is therefore more widely used.

[0003] Reverse osmosis seawater desalination requires a high-pressure plunger pump to pressurize seawater to 6-7 MPa to overcome its osmotic pressure. Currently, the most ideal seawater pressurization equipment is the plunger-type booster device. This device mainly consists of a piston, piston rod, pump cylinder, pump valve, and crank connecting rod. Its working principle is that the piston reciprocates under external force, changing the volume and pressure within the working chamber. This creates a negative pressure within the working chamber, drawing liquid from the storage tank into the working chamber through the suction valve. As the plunger reciprocates, opening and closing the suction and discharge valves, the liquid in the working chamber is compressed, increasing its pressure, and is then discharged through the discharge valve, achieving the purpose of liquid delivery.

[0004] Because the piston of the plunger-type booster device changes speed constantly during movement, the water pressure at the outlet of the plunger-type booster device is pulsating. The pulsation of seawater pressure seriously affects the performance of the reverse osmosis membrane module and the stability of the entire seawater desalination system, bringing alternating loads to the reverse osmosis membrane module, damaging the membrane module, and reducing its performance and service life. Therefore, it is better to stabilize the pressure of the pulsating seawater before it enters the membrane module.

[0005] To avoid damaging the reverse osmosis membrane module, the material must be pressure-stabilized before entering the reverse osmosis membrane module. Existing technology proposes a method and device for integrated seawater desalination and salt production. The method is as follows: seawater drawn from the ocean is converted into pulsating high-pressure seawater through a plunger-type pressurization device. The pulsating high-pressure seawater and a stable hot gas flow exchange energy in a pulsating energy exchange device, converting into stable high-pressure seawater and pulsating hot gas flow. The pressure-stabilized high-pressure seawater is then used to produce fresh water through the reverse osmosis membrane module. The high-pressure concentrated seawater discharged from the reverse osmosis membrane module is sprayed into the pulsating hot gas flow for evaporation and crystallization to produce salt.

[0006] Another voltage stabilization method is to use an elastic pressure-switching bladder structure and a counterweight structure. The purpose of both is to temporarily store the pulsating energy elsewhere and play a role in temporary voltage stabilization.

[0007] The aforementioned technology absorbs pulsating energy after it is generated. While this can recover some of the pulsating energy and improve energy utilization efficiency, and to some extent prevent damage to the reverse osmosis membrane module, this method absorbs or eliminates the pulsating energy after it is generated, providing only temporary pressure stabilization. However, due to limited energy exchange efficiency or the limited ability of the elastic pressure-reducing bladder or counterweight to absorb pulsating energy, it cannot completely absorb or transfer the generated pulsating energy. This poses a potential risk to the stable operation of the system. Summary of the Invention

[0008] The purpose of this invention is to provide a seawater desalination system that can stabilize the pressure in a timely manner when the seawater pressure fluctuates.

[0009] The following technical solutions are used to achieve the above objectives.

[0010] The first aspect of the present invention provides a seawater desalination system, the seawater desalination system comprising a first channel, a second channel, a plunger pump device, a pressure stabilizing device, and a reverse osmosis device;

[0011] The first channel is connected to the second channel. The plunger pump is movably disposed within the first channel. The pressure stabilizing device and the reverse osmosis device are both disposed within the second channel. The pressure stabilizing device includes a piston, a stop, and an adjusting mechanism. The piston is elastically disposed within the second channel, and the stop is disposed within the second channel and located within the piston's stroke range. The adjusting mechanism acts on the piston and adjusts the distance between the piston and the stop. The piston reaches its maximum compression stroke when it abuts against the stop. When the seawater pressure entering the second channel is too high, the piston is squeezed to form elastic compression. After the seawater pressure in the second channel decreases, the piston releases the pressure to further pressurize the seawater in the second channel, so that the pressure of the seawater in the second channel is stabilized.

[0012] In some embodiments, the adjusting mechanism includes a fixed plate, an elastic element, a fixed column, and an adjusting element; the fixed plate and the piston are connected through the elastic element, the fixed column is disposed in the second channel, and the fixed plate and the piston are movably disposed through the fixed column, the adjusting element is disposed on the side of the fixed plate away from the elastic element, and the adjusting element is movably connected to the fixed column, and when the adjusting element moves relative to the fixed column, it can move the piston closer to or away from the stop through the fixed plate.

[0013] In some embodiments, the fixed column is provided with a threaded section, and the adjusting element is an adjusting nut, which is threadedly connected to the threaded section.

[0014] In some embodiments, multiple elastic elements are provided, and each elastic element cooperates to support the piston on the fixed plate.

[0015] In some embodiments, two stops are provided, with the two stops disposed on the sidewalls of opposite sides of the second channel along the direction of piston movement; and / or,

[0016] The second channel is arranged horizontally, and the pressure stabilizing device and the reverse osmosis device are arranged at opposite ends in the horizontal direction of the second channel. The first channel is arranged vertically and intersects and connects with the middle position of the second channel, and the second channel is located above the first channel.

[0017] In some embodiments, the first channel has an inlet and an outlet, the outlet of the first channel is connected to the second channel, a first flow direction limiting device is provided at the inlet of the first channel, and a second flow direction limiting device is provided at the outlet of the first channel. When the plunger pump device moves in the first channel away from the outlet, the first flow direction limiting device controls the inlet to open, allowing external seawater to flow into the first channel. When the plunger pump device moves in the first channel towards the outlet, the second flow direction limiting device controls the outlet to open, allowing seawater to enter the second channel from the first channel.

[0018] In some embodiments, the first flow direction limiting device and the second flow direction limiting device are one-way valves.

[0019] In some embodiments, the outlet is disposed opposite to the plunger pump device, and the inlet is opened on the side of the first channel corresponding to the direction of movement of the plunger pump device.

[0020] In some embodiments, the reverse osmosis device is a reverse osmosis membrane device.

[0021] A second aspect of the present invention provides a seawater desalination method using the seawater desalination system described above, comprising a pressurization step and a pressure stabilization step:

[0022] The pressurization step includes: controlling the plunger pump device to move within the first channel, so that external seawater flows into the first channel;

[0023] Subsequently, the plunger pump device moves in the reverse direction within the first channel, causing the seawater inside the first channel to enter the second channel in the form of pulsating energy from the first channel.

[0024] The pressure stabilization step includes: after the seawater enters the second channel, the pulsating potential energy of the seawater causes the seawater pressure in the second channel to change relative to the initial pressure, which pushes the piston to move in the second channel to pressurize or depressurize the seawater in the second channel. When the pressure of the seawater entering the second channel is too high, the piston is squeezed to form elastic compression to perform a pressure relief operation. After the pressure of the seawater in the second channel drops, the piston releases the pressure to pressurize the seawater in the second channel, so that the pressure of the seawater in the second channel is in a stable state.

[0025] The technical solution provided by this invention has the following advantages and effects:

[0026] This seawater desalination system, driven by a plunger pump, propels seawater with pulsating energy from the first channel into the second channel. Upon entering the second channel, the pulsating potential energy causes a change in pressure relative to the initial value. When the pressure is too high, the piston is compressed, acting as a buffer. As the high-pressure seawater pressure decreases, the piston releases the pressure, further pressurizing the seawater and stabilizing it. This ensures a stable pressure for the seawater entering the reverse osmosis unit, effectively preventing damage from excessive pulsating energy and extending the unit's lifespan. The system also incorporates an adjustment mechanism that regulates the distance between the piston and the stop, allowing for adjustment of the maximum compression stroke based on the pressure range applied by the plunger pump and the required pressure range of the reverse osmosis unit. This ensures the pressure within the second channel is controllable, preventing it from becoming too high or too low and thus minimizing impacts on the unit's lifespan and the quality of the desalinated water. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the seawater desalination system according to an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100. Seawater desalination system;

[0030] 1. First channel; 11. Inlet; 12. Outlet; 2. Second channel; 3. Plunger pump device; 4. Pressure stabilizing device; 41. Piston component; 42. Baffle component; 43. Adjusting mechanism; 431. Fixing plate; 432. Elastic component; 433. Fixing column; 434. Adjusting component; 5. Reverse osmosis device; 6. First flow direction restriction device; 7. Second flow direction restriction device. Detailed Implementation

[0031] To facilitate understanding of the present invention, specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0032] Unless otherwise specified or defined, the terms "first," "second," etc., used in this document are for distinguishing names only and do not represent a specific number or order.

[0033] Unless otherwise specified or defined, the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0034] It should be noted that in this article, "fixed to" or "connected to" can mean directly fixed to or connected to a component, or indirectly fixed to or connected to a component.

[0035] This invention provides a seawater desalination system 100, such as... Figure 1 As shown, the seawater desalination system 100 includes a first channel 1, a second channel 2, a plunger pump device 3, a pressure stabilizing device 4, and a reverse osmosis device 5.

[0036] The first channel 1 is connected to the second channel 2. The plunger pump device 3 is movably disposed in the first channel 1. The pressure stabilizing device 4 and the reverse osmosis device 5 are both disposed in the second channel 2. The pressure stabilizing device 4 includes a piston 41, a stop 42 and an adjusting mechanism 43. The piston 41 is elastically disposed in the second channel 2, and the stop 42 is disposed in the second channel 2 and located within the movement stroke range of the piston 41. The adjusting mechanism 43 acts on the piston 41 and adjusts the distance between the piston 41 and the stop 42. The piston 41 moves to the maximum compression stroke when it abuts against the stop 42. The adjusting mechanism 43 can act on the piston 41 to adjust the distance between the normally uncompressed piston 41 and the stop 42. Alternatively, in other embodiments, the adjusting mechanism 43 can also act on the stop 42 to adjust the distance between the normally uncompressed piston 41 and the stop 42. This allows the maximum compression stroke of the piston 41 to be adjusted according to the pressure range that the plunger pump device 3 can apply and the pressure range required by the reverse osmosis device 5. When the pressure of the seawater entering the second channel 2 is too high, the piston 41 is squeezed to form elastic compression. After the pressure of the seawater in the second channel 2 drops, the piston 41 releases the pressure to further pressurize the seawater in the second channel 2 so that the pressure of the seawater in the second channel 2 is stabilized.

[0037] Understandably, when seawater needs to be desalinated via reverse osmosis, the plunger pump device 3 is pulled backward within the first channel 1, increasing the space inside the first channel 1. This creates a negative pressure inside the first channel 1 compared to the external seawater environment outside the inlet 11 of the first channel 1, allowing external seawater to flow into the first channel 1. Subsequently, the plunger pump device 3 is pushed in the opposite direction within the first channel 1, reducing the space inside the first channel 1. This creates a positive pressure inside the first channel 1 compared to the second channel 2, pushing seawater into the second channel 2 in the form of pulsating energy. After the seawater enters the second channel 2, the pulsating potential energy causes the seawater pressure in the second channel 2 to change relative to the initial pressure value, thus pushing the piston 41 to move within the second channel 2 to pressurize or depressurize the seawater in the second channel 2. When the seawater pressure entering the second channel 2 is too high, the piston 41 is squeezed and elastically compressed, which acts as a buffer. After the high-pressure seawater pressure in the second channel 2 drops, the piston 41 releases the pressure, further pressurizing the seawater in the second channel 2 to stabilize the pressure and ensure a stable seawater pressure entering the reverse osmosis unit 5. This effectively prevents excessive seawater pulsation energy from damaging the reverse osmosis unit 5, thereby improving its service life. Combined with the action of the regulating mechanism 43 on the piston 41, before seawater enters the second channel, the distance between the normally uncompressed piston 41 and the stop 42 is adjusted. This allows the maximum compression stroke of the piston 41 to be adjusted according to the pressure range that the plunger pump device 3 can apply and the pressure range required by the reverse osmosis unit 5. This ensures that the pressure range of the seawater inside the second channel 2 is controllable, maintaining a stable pressure within a certain range, neither too high nor too low, effectively avoiding affecting the service life of the reverse osmosis unit 5 and the quality of the freshwater. The pressure range is typically set between the pressure that the plunger pump device 3 can apply and the pressure that the reverse osmosis device 5 can withstand, so that the seawater pressure in the second channel 2 fluctuates within a controllable range.

[0038] In some embodiments, such as Figure 1As shown, the adjustment mechanism 43 includes a fixed plate 431, an elastic element 432, a fixed column 433, and an adjusting element 434. The fixed plate 431 and the piston 41 are connected by the elastic element 432. The fixed column 433 is disposed in the second channel 2, and the fixed plate 431 and the piston 41 are movably inserted through the fixed column 433. The adjusting element 434 is disposed on the side of the fixed plate 431 away from the elastic element 432, and the adjusting element 434 is movably connected to the fixed column 433. When the adjusting element 434 moves relative to the fixed column 433, it can move the piston 41 closer to or away from the stop 42 through the fixed plate 431. Understandably, by fixing the stop 42 to a preset position in the second channel 2, an external force is applied to the adjusting member 434, causing the adjusting member 434 to move relative to the fixed column 433. This movement of the adjusting member 434 then guides the piston 41 to move closer to or further away from the stop 42, adjusting the distance between the piston 41 and the stop 42 in its uncompressed, normal state. Both the piston 41 and the fixed plate 431 have through holes. The fixed column 433 movably passes through these through holes, and the two are sealed together. The piston 41 slides in the second channel 2 and is also sealed to the inner wall of the second channel 2, preventing seawater from entering the pressure stabilizing device 4 and thus avoiding interference with its movement.

[0039] In some embodiments, a limiting member may be provided at the end of the fixing post 433 to prevent the piston 41 from sliding out further, thereby preventing the piston 41 from detaching from the fixing post 433.

[0040] In some embodiments, such as Figure 1 As shown, the fixed column 433 is provided with a threaded section, and the adjusting member 434 is an adjusting nut, which is threadedly connected to the threaded section. Understandably, through the threaded engagement of the adjusting nut and the threaded section of the fixed column 433, the piston 41 can be moved along the fixed column 433 to be close to or away from the stop 42 by rotating the adjusting nut. After moving into position, it is locked by the threaded engagement of the adjusting nut and the threaded section, thereby preventing the fixed plate 431 from moving outward relative to the fixed column 433. This avoids displacement of the fixed plate 431 under the pulsating pressure of seawater, which would cause a change in the normal distance between the piston 41 and the stop 42. This provides a stable locking mechanism and convenient adjustment.

[0041] In some embodiments, such as Figure 1 As shown, multiple elastic elements 432 are provided, and each elastic element 432 cooperates to support the piston 41 on the fixed plate 431. By having multiple elastic elements 432 jointly support the piston 41, the piston 41 can be subjected to uniform force and its elastic load capacity can be improved.

[0042] In some embodiments, such as Figure 1 As shown, two baffles 42 are provided, and the two baffles 42 are disposed on the sidewalls of opposite sides of the second channel 2 along the moving direction of the piston 41. By providing two baffles 42 to jointly block further compression of the piston 41, the resistance on the piston 41 can be dispersed, and the pressure on each baffle 42 can be reduced, thereby improving the overall stability and durability.

[0043] In some embodiments, such as Figure 1 As shown, the second channel 2 is arranged horizontally, with the pressure stabilizing device 4 and the reverse osmosis device 5 located at opposite ends of the second channel 2 in the horizontal direction. The first channel 1 is arranged vertically and intersects and connects with the middle of the second channel 2, with the second channel 2 located above the first channel 1. Understandably, through the specific structural arrangement of these two channels, seawater entering the second channel 2 from the first channel 1 will not directly impact the reverse osmosis device 5, but will instead impact the inner wall of the second channel 2. The pressure stabilizing device 4 then stabilizes the pressure of the seawater in the second channel 2 before it passes through the reverse osmosis device 5 to produce fresh water. This avoids damage to the reverse osmosis device 5 caused by pulsating seawater directly impacting it.

[0044] In some embodiments, such as Figure 1As shown, the first channel 1 has an inlet 11 and an outlet 12. The outlet 12 of the first channel 1 is connected to the second channel 2. A first flow direction limiting device 6 is provided at the inlet 11 of the first channel 1, and a second flow direction limiting device 7 is provided at the outlet 12 of the first channel 1. When the plunger pump device 3 moves away from the outlet 12 in the first channel 1, the first flow direction limiting device 6 controls the inlet 11 to open, allowing external seawater to flow into the first channel 1. When the plunger pump device 3 moves towards the outlet 12 in the first channel 1, the second flow direction limiting device 7 controls the outlet 12 to open, allowing seawater to enter the second channel 2 from the first channel 1. Specifically, the first flow direction limiting device 6 is a directional flow limiting device, which only allows seawater to flow in from the outside through the inlet 11 of the first channel 1, but seawater inside the first channel 1 cannot flow out through the inlet 11. Similarly, the second flow direction limiting device 7 is also a directional flow limiting device, which only allows seawater to flow into the second channel 2 through the outlet 12 of the first channel 1, but seawater inside the second channel 2 cannot flow out to the first channel 1 through the outlet 12. Understandably, the inlet 11 of the first channel 1 can be connected to an external storage tank containing seawater drawn from the ocean. When the plunger pump device 3 pulls outward until a negative pressure is formed between the first channel 1 and the external seawater environment outside the inlet 11, the first flow direction limiting device 6 controls the inlet 11 to open, allowing external seawater to flow into the first channel 1. At this time, the second flow direction limiting device 7 closes. Subsequently, the plunger pump device 3 moves in the reverse direction within the first channel 1, reducing the internal space of the first channel 1. When a positive pressure is formed between the inside of the first channel 1 and the second channel 2, the second flow direction limiting device 7 controls the outlet 12 to open, allowing seawater to enter the second channel 2 from the first channel 1. At this time, the first flow direction limiting device 6 closes. Furthermore, it should be noted that the plunger pump device 3 has a conventional structure and will not be described in detail here.

[0045] Specifically, the first flow direction limiting device 6 and the second flow direction limiting device 7 are one-way valves. The core function of the one-way valve is to allow fluid to flow freely in one direction while effectively preventing fluid from flowing in the opposite direction. This characteristic ensures that the flow direction of seawater in the first channel 1 and the second channel 2 is precisely controlled, avoiding system turbulence, equipment damage, or safety accidents that may be caused by seawater backflow, and simplifying the structural design. It should be noted that the initial pressure of the piston 41 is less than the maximum pressure that the plunger pump device 3 can provide. This allows the seawater in the first channel 1 to smoothly enter the second channel 2 through the one-way valve 2, while ensuring that the piston 41 can play its role in time to stabilize the pressure when the seawater in the first channel 1 enters the second channel 2. The function of the baffle 42 is to prevent the piston 41 from being over-compressed due to inertia during its movement, which would cause the seawater pressure in the first channel 1 to be too low and affect the reverse osmosis effect.

[0046] In some embodiments, such as Figure 1 As shown, the outlet 12 is positioned opposite to the plunger pump device 3, and the inlet 11 is located on the side of the first channel 1 corresponding to the direction of movement of the plunger pump device 3. By positioning the outlet 12 opposite to the plunger pump device 3, the plunger pump device 3 can smoothly transport seawater through the outlet 12 into the second channel 2 during its reciprocating motion. This ensures that seawater can flow out directly and efficiently during pumping, reducing the retention and eddies of seawater within the first channel 1, thereby improving pumping efficiency.

[0047] In some embodiments, the reverse osmosis device 5 is a reverse osmosis membrane device. This reverse osmosis membrane device is a conventional device. Seawater is pressurized by the plunger pump device 3, and then stabilized by the pressure stabilizing device 4 before entering the reverse osmosis membrane device. Separation occurs through the reverse osmosis membrane device. Under pressure, water molecules pass through the membrane to the other side, forming fresh water, while salt and other impurities are retained on one side of the membrane and discharged with the concentrate. This method has the advantages of high efficiency, stability, energy saving, and environmental friendliness.

[0048] This invention also provides a seawater desalination method using the seawater desalination system 100 described above, including a pressurization step and a pressure stabilization step:

[0049] The pressurization step includes: controlling the plunger pump device 3 to move within the first channel 1, so that external seawater flows into the first channel 1;

[0050] Subsequently, the plunger pump device 3 moves in the reverse direction in the first channel 1, so that the seawater in the first channel 1 enters the second channel 2 from the first channel 1 in the form of carrying pulsating energy.

[0051] The pressure stabilization step includes: after the seawater enters the second channel 2, the pulsating potential energy of the seawater causes the seawater pressure in the second channel 2 to change relative to the initial pressure, which pushes the piston 41 to move in the second channel 2 to pressurize or depressurize the seawater in the second channel 2. When the pressure of the seawater entering the second channel 2 is too high, the piston 41 is squeezed to form elastic compression to perform a pressure relief operation. After the pressure of the seawater in the second channel 2 drops, the piston 41 releases the pressure to pressurize the seawater in the second channel 2, so that the pressure of the seawater in the second channel 2 is in a stable state.

[0052] In summary, this seawater desalination method, through the use of the seawater desalination system 100, enables the plunger pump 3 to propel seawater, carrying pulsating energy, from the first channel 1 into the second channel 2. Upon entering the second channel 2, the pulsating potential energy of the seawater causes a change in the seawater pressure within the second channel 2 relative to the initial pressure value. When the pressure of the seawater entering the second channel 2 becomes excessive, the piston 41 is compressed elastically, acting as a buffer. After the high-pressure seawater pressure in the second channel 2 decreases, the piston 41 releases the pressure, further pressurizing the seawater in the second channel 2 to stabilize the pressure and ensure that the seawater entering the reverse osmosis unit 5... The seawater pressure is relatively stable, effectively preventing excessive seawater pulsation energy from damaging the reverse osmosis unit 5, thereby improving the service life of the reverse osmosis unit 5. Combined with the action of the adjustment mechanism 43 on the piston 41, the distance between the normally uncompressed piston 41 and the stop 42 is adjusted. This allows the maximum compression stroke of the piston 41 to be adjusted according to the pressure range that the plunger pump device 3 can apply and the pressure range required by the reverse osmosis unit 5, so that the pressure range of the seawater inside the second channel 2 is controllable. This ensures that the seawater pressure inside the second channel 2 is stable within a certain range, neither too high nor too low, effectively avoiding affecting the service life of the reverse osmosis unit 5 and the quality of the freshwater.

[0053] The above embodiments are not an exhaustive list based on the present invention, and there may be many other embodiments not listed. Any substitutions and improvements made without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A sea water desalination system, characterized in that, The seawater desalination system comprises a first channel, a second channel, a plunger pump device, a pressure stabilizing device and a reverse osmosis device; The first channel is communicated with the second channel, the plunger pump device is movably arranged in the first channel, the pressure stabilizing device and the reverse osmosis device are both arranged in the second channel, the pressure stabilizing device comprises a piston, a stopper and an adjusting mechanism; the piston is elastically arranged in the second channel, the stopper is arranged in the second channel and located in the movement stroke interval of the piston, the adjusting mechanism acts on the piston and adjusts the distance between the piston and the stopper, the piston is in the maximum compression stroke when it is in abutment with the stopper, when the seawater pressure in the second channel is too large, the piston is elastically compressed, after the seawater pressure in the second channel is reduced, the piston releases the pressure to further pressurize the seawater in the second channel, so that the seawater pressure in the second channel is in a stable state; The adjusting mechanism comprises a fixed plate, an elastic member, a fixed column and an adjusting member; the fixed plate and the piston are connected by the elastic member, the fixed column is arranged in the second channel, and the fixed plate and the piston movably pass through the fixed column, the adjusting member is arranged on the side of the fixed plate away from the elastic member, and the adjusting member is movably connected to the fixed column; when the adjusting member moves relative to the fixed column, it can drive the piston to move closer to or away from the stopper through the fixed plate.

2. The system for desalination of seawater as claimed in claim 1 wherein, The fixed column is provided with a threaded segment, and the adjusting member is an adjusting nut which is threadedly connected with the threaded segment.

3. The system for desalination of seawater as claimed in claim 2 wherein, The elastic member is provided with a plurality of elastic members which cooperate to support the piston on the fixed plate.

4. The system for desalination of seawater as claimed in claim 1 wherein, The stopper is provided with two stoppers which are arranged on the side walls on opposite sides of the second channel along the movement direction of the piston; and / or The second channel is arranged transversely, the pressure stabilizing device and the reverse osmosis device are arranged at opposite ends of the second channel in the transverse direction, the first channel is arranged vertically and intersects with the middle position of the second channel to communicate, and the second channel is located above the first channel.

5. The system for desalination of seawater according to any one of claims 1-4, characterized in that, The first channel is provided with an inlet and an outlet, the outlet of the first channel is communicated with the second channel, the first flow direction limiting device is arranged at the inlet of the first channel, the second flow direction limiting device is arranged at the outlet of the first channel, when the plunger pump device moves in the first channel away from the outlet, the first flow direction limiting device controls the opening of the inlet to allow external seawater to flow into the first channel, when the plunger pump device moves in the first channel towards the outlet, the second flow direction limiting device controls the opening of the outlet to allow seawater to flow from the first channel into the second channel.

6. The system for desalination of seawater as claimed in claim 5 wherein, The first flow direction limiting device and the second flow direction limiting device are one-way valves.

7. The system for desalination of seawater as claimed in claim 5 wherein, The outlet is arranged opposite to the plunger pump device, and the inlet is arranged on one side of the first channel corresponding to the movement direction of the plunger pump device.

8. The system for desalination of seawater according to any one of claims 1-4, wherein, The reverse osmosis device is a reverse osmosis membrane device.

9. A method of desalination of sea water, characterized in that, A sea water desalination system as claimed in any one of claims 1-8, characterized in that it comprises a pressurization step and a pressure stabilization step. The pressurization step comprises controlling the plunger pump device to move within the first channel so that the external sea water flows into the first channel; Subsequently, the plunger pump device moves reversely within the first channel so that the sea water inside the first channel enters the second channel in the form of carrying pulsating energy; The pressure stabilization step comprises that after the sea water enters the second channel, when the pulsating potential energy of the sea water causes the sea water pressure in the second channel to change relative to the initial pressure, the piston member is pushed to move within the second channel to pressurize or depressurize the sea water in the second channel, when the sea water pressure entering the second channel is too large, the piston member is squeezed to form elastic compression for depressurization operation, after the sea water pressure in the second channel decreases, the piston member releases the pressure to pressurize the sea water in the second channel, so that the sea water pressure in the second channel is in a stable state.

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