Energy recovery device and recovery method for seawater desalination

Abstract

The present invention relates to the technical field of seawater desalination equipment, and in particular discloses an energy recovery device and recovery method for seawater desalination. The device comprises a first pressure-bearing pipe and a second pressure-bearing pipe arranged in parallel; one end of the two pressure-bearing pipes is vertically connected to a concentrated brine switching pipe at the same time, and the other ends of the two pressure-bearing pipes are coaxially connected to a hydraulic switching valve through a piston structure; one side of the concentrated brine switching pipe is coaxially connected to a third hydraulic switching valve through a third piston structure; a high-pressure concentrated brine inlet and two upper and lower low-pressure concentrated brine outlets are provided on the concentrated brine switching pipe; the first or second hydraulic switching valve is used to transfer the high-pressure water flow energy of the corresponding pressure-bearing pipe to the third hydraulic switching valve, and the waterway switching of the high-pressure concentrated brine in the concentrated brine switching pipe is realized by the movement of the third piston structure, so that the two pressure-bearing pipes can cyclically and uninterruptedly recover energy, and the switching process is all driven by hydraulic power, which is environmentally friendly and energy-saving.

Description

Technical Field

[0001] The invention relates to the technical field of seawater desalination equipment, and in particular discloses an energy recovery device and a recovery method for seawater desalination. Background Art

[0002] With the growth of drinking water demand and the increase of energy cost, the scalability and energy-saving design of seawater reverse osmosis process make this process the first choice for water-scarce areas around the world. The seawater desalination process refers to the production of fresh water by desalination of seawater. It is an open-source incremental technology for realizing water resource utilization. It can increase the total amount of fresh water and is not affected by time, space and climate. It can ensure the stable supply of drinking water for coastal residents and industrial boiler water replenishment. In the process of seawater desalination, seawater is filtered through the reverse osmosis membrane to produce fresh water, and the concentrated brine that does not pass through the reverse osmosis membrane is discharged; in the prior art, the energy of high-pressure concentrated brine can be used to pressurize low-pressure seawater, and the low-pressure seawater is filtered through the osmotic membrane assembly. After the high-pressure concentrated brine is depressurized, it becomes low-pressure concentrated brine and is discharged, achieving the purpose of energy recovery.

[0003] The devices currently available on the market for seawater desalination energy recovery are often complex in structure and have low recovery efficiency, and cannot be combined and used according to on-site usage conditions. Summary of the invention

[0004] In order to solve the above-mentioned technical problems existing in the prior art, this patent provides an energy recovery device and recovery method for seawater desalination.

[0005] The technical solution adopted by this patent to solve the technical problems existing in the known technology is:

[0006] An energy recovery device for seawater desalination, characterized in that: it comprises a first pressure-bearing pipe and a second pressure-bearing pipe arranged in parallel; one end of the two pressure-bearing pipes is vertically connected to a concentrated brine switching pipe at the same time, and the other end of the first pressure-bearing pipe is coaxially connected to a first hydraulic switching valve through a first piston structure, and the other end of the second pressure-bearing pipe is coaxially connected to a second hydraulic switching valve through a second piston structure; one side of the concentrated brine switching pipe is coaxially connected to a third hydraulic switching valve through a third piston structure;

[0007] The concentrated brine switching pipe is provided with a high-pressure concentrated brine inlet and two upper and lower low-pressure concentrated brine outlets; the high-pressure concentrated brine inlet is located between the first pressure-bearing pipe and the second pressure-bearing pipe, and the two pressure-bearing pipes are located between the upper and lower low-pressure concentrated brine outlets;

[0008] The first or second hydraulic switching valve is used to transfer the high-pressure water flow energy of the corresponding pressure pipe to the third hydraulic switching valve, and realize the waterway switching of the high-pressure concentrated brine in the concentrated brine switching pipe through the movement of the third piston structure;

[0009] A low-pressure seawater inlet and a high-pressure seawater outlet are provided on the first and second pressure-bearing pipes at one end away from the concentrated brine switching pipe. The low-pressure seawater enters the corresponding pressure-bearing pipe through the low-pressure seawater inlet, and the high-pressure concentrated brine enters the concentrated brine switching pipe and is guided into the pressure-bearing pipe filled with low-pressure seawater through the third piston structure. The pressure of the high-pressure concentrated brine in the pressure-bearing pipe is transmitted to the low-pressure seawater, and then the low-pressure seawater is pressurized and discharged through the high-pressure seawater outlet, and then is transported to the osmotic membrane for filtration after passing through a booster pump, and then the high-pressure concentrated brine is depressurized to become low-pressure concentrated brine and is discharged through the low-pressure concentrated brine outlet.

[0010] Furthermore, the first piston structure includes two piston blocks located in the first hydraulic switching valve, the two piston blocks are spaced a certain distance apart and connected as a whole by a first piston rod, one end of the first piston rod is located in the first hydraulic switching valve, and the other end is located in the first pressure-bearing pipe, and the first piston rod located inside the first pressure-bearing pipe is provided with multiple rows of water inlet holes, so that the seawater in the first pressure-bearing pipe enters the first piston rod through the water inlet holes, and is introduced into the first hydraulic switching valve through the first piston rod and the water outlet holes provided on the piston block near the first pressure-bearing pipe. The second piston structure has the same structure as the first piston structure; the third piston structure includes three piston blocks connected as a whole by a piston rod, one of which is located in the third hydraulic switching valve, and the other two piston blocks are located in the concentrated brine switching pipe.

[0011] Furthermore, an elastic structure in contact with the first piston structure is provided in the first hydraulic switching valve. In addition, two water inlets and outlets are provided on the first hydraulic switching valve, and the distance between the two water inlets and outlets is smaller than the distance between the two piston blocks on the first piston structure; the second hydraulic switching valve has the same structure as the first hydraulic switching valve; and the third hydraulic switching valve is also provided with two water inlets and outlets separated by a certain distance.

[0012] Furthermore, the recovery method of the energy recovery device for seawater desalination has the following working steps:

[0013] S1, the pre-treated low-pressure seawater enters the first pressure-bearing pipe through the low-pressure seawater inlet, and the high-pressure concentrated brine enters the concentrated brine switching pipe and is guided by the third piston structure into the first pressure-bearing pipe filled with low-pressure seawater;

[0014] S2, the high-pressure concentrated salt water continuously pushes the first piston structure to move in the direction of the first hydraulic switching valve. During the movement, the pressure of the high-pressure concentrated salt water is transmitted to the low-pressure seawater, and then the low-pressure seawater is pressurized and discharged through the check valve provided in the high-pressure seawater outlet; at the same time, part of the pressurized seawater enters the first piston rod through the water inlet hole, and is introduced into the first hydraulic switching valve through the water outlet hole; at this time, the first piston structure compresses the elastic structure in the first hydraulic switching valve during the movement;

[0015] S3, when the piston block with the water outlet hole moves to between the two water inlets and outlets of the first hydraulic switching valve, the high-pressure seawater in the first hydraulic switching valve enters the third hydraulic switching valve through one of the water inlets and outlets and the corresponding pipeline, and the high-pressure seawater pushes the third piston rod to move downward for switching, and the piston located in the concentrated brine switching pipe on the third piston rod moves accordingly, and the channel for the high-pressure concentrated brine to enter the first pressure-bearing pipe is cut off; during the switching movement of the third piston rod, the seawater in the third hydraulic switching valve is discharged into the second hydraulic switching valve through the other water inlet and outlet thereon; this part of the seawater is discharged through the water inlet and outlet on the second hydraulic switching valve;

[0016] S4. After the high-pressure brine is depressurized, the elastic structure in the first hydraulic switching valve rebounds, and with the injection of low-pressure seawater, the first piston structure discharges the low-pressure brine through one of the low-pressure brine outlets during the return stroke; the high-pressure brine entering the brine switching pipe is introduced into the second pressure pipe and pressurizes the low-pressure seawater entering the second pressure pipe, and the cycle between the two pressure pipes repeats itself.

[0017] The advantages and positive effects of this patent are:

[0018] The energy recovery device of the present invention is an isobaric device with a simple design. It pressurizes low-pressure seawater through high-pressure concentrated brine, and uses three hydraulic switching valves to switch the waterway, so that the two pressure pipes can circulate back and forth uninterruptedly for energy recovery, and the switching process is all driven by hydraulic power, which is environmentally friendly and energy-saving. It has been verified that the device can recover up to 98% of the energy in high-pressure concentrated brine, thereby having a substantial impact on the operating cost of the equipment. In addition, the device can place multiple sets of devices in parallel according to the on-site conditions to meet greater energy recovery needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a working principle diagram of the energy recovery device in the present invention;

[0020] Figure 2 Another working principle diagram of the energy recovery device in the present invention;

[0021] Figure 3 It is a schematic diagram of the structure of the first and second pressure-bearing pipes and the concentrated brine switching pipe in the present invention;

[0022] Figure 4 A three-dimensional diagram of the first piston structure and the first hydraulic switching valve in the present invention;

[0023] Figure 5 It is a three-dimensional diagram of the first piston structure in the present invention.

[0024] In the figure: 1. first pressure-bearing pipe; 1-1. low-pressure seawater inlet; 1-2. high-pressure seawater outlet; 2. second pressure-bearing pipe; 3. concentrated brine switching pipe; 31. high-pressure concentrated brine inlet; 32. low-pressure concentrated brine outlet; 4. first piston structure; 41. first piston block; 42. first piston rod; 43. first water inlet; 44. first water outlet; 5. second piston structure; 6. third piston structure; 61. third piston block; 62. third piston rod; 7. first hydraulic switching valve; 71. elastic structure; 72. water inlet and outlet; 8. second hydraulic switching valve; 9. third hydraulic switching valve; 10. low-pressure seawater; 11. high-pressure concentrated brine; 12. low-pressure concentrated brine; 13. high-pressure seawater. DETAILED DESCRIPTION

[0025] In order to further understand the content, features and effects of the invention of this patent, the following embodiments are given as examples and described in detail with the accompanying drawings as follows:

[0026] See also Figures 1 to 5 The present invention discloses an energy recovery device for seawater desalination, comprising a first pressure-bearing pipe 1 and a second pressure-bearing pipe 2 arranged in parallel; one end of the two pressure-bearing pipes is vertically connected to a concentrated brine switching pipe 3 at the same time, and the other end of the first pressure-bearing pipe 1 is coaxially connected to a first hydraulic switching valve 7 through a first piston structure 4, and the other end of the second pressure-bearing pipe 2 is coaxially connected to a second hydraulic switching valve 8 through a second piston structure 5; one side of the concentrated brine switching pipe 3 is coaxially connected to a third hydraulic switching valve 9 through a third piston structure 6; specifically, a high-pressure concentrated brine inlet 31 and two upper and lower low-pressure concentrated brine outlets 32 are provided on the concentrated brine switching pipe 3; the high-pressure concentrated brine inlet 31 is located between the two pressure-bearing pipes, and the two pressure-bearing pipes are located between the upper and lower low-pressure concentrated brine outlets 32, so that the high-pressure concentrated brine 11 enters the first pressure-bearing pipe 1 or the second pressure-bearing pipe 2 through the high-pressure concentrated brine inlet 31 of the concentrated brine switching pipe 3, and is discharged from the low-pressure concentrated brine outlet 32 ​​in the form of low-pressure concentrated brine 12. The first piston structure 4 includes two piston blocks 41 located in the first hydraulic switching valve 7, the two piston blocks 41 are spaced a certain distance apart and connected as a whole by a first piston rod 42, one end of the first piston rod 42 is located in the first hydraulic switching valve 7, and the other end is located in the first pressure-bearing pipe 1, and the first piston rod 42 located inside the first pressure-bearing pipe 1 is provided with multiple rows of water inlet holes 43, so that the seawater in the first pressure-bearing pipe 1 enters the first piston rod 42 through the water inlet holes 43, and is introduced into the first hydraulic switching valve 7 through the first piston rod 42 and the water outlet holes 44 provided on the piston block 41 near the first pressure-bearing pipe 1. The second piston structure 5 has the same structure as the first piston structure 4, and will not be described here. The third piston structure 6 includes three piston blocks 41 connected as a whole by a piston rod, one of which is located in the third hydraulic switching valve 9, and the other two piston blocks 41 are located in the concentrated brine switching pipe 3.

[0027] The first or second hydraulic switching valve 8 is used to transfer the high-pressure water flow energy of the corresponding pressure pipe to the third hydraulic switching valve 9, and realize the waterway switching of the high-pressure concentrated brine 11 in the concentrated brine switching pipe 3 through the movement of the third piston structure 6. The specific structure is as follows:

[0028] The first hydraulic switching valve 7 is provided with an elastic structure 71 in contact with the first piston structure 4. In addition, the first hydraulic switching valve 7 is provided with two water inlets and outlets 72, and the distance between the two water inlets and outlets 72 is smaller than the distance between the two piston blocks 41 on the first piston structure 4. The second hydraulic switching valve 8 has the same structure as the first hydraulic switching valve 7, which will not be described here. The third hydraulic switching valve 9 is also provided with two water inlets and outlets 72 spaced a certain distance apart.

[0029] A low-pressure seawater inlet 11 and a high-pressure seawater outlet 12 are provided at one end of the first and second pressure pipes 2 away from the concentrated brine switching pipe 3. The low-pressure seawater 10 enters the corresponding pressure pipe through the low-pressure seawater inlet 11, and the high-pressure concentrated brine 11 enters the concentrated brine switching pipe 3 and is guided into the pressure pipe filled with low-pressure seawater 10 through the third piston structure 6. The pressure of the high-pressure concentrated brine 11 in the pressure pipe is transmitted to the low-pressure seawater 10, and then the low-pressure seawater 10 is pressurized and discharged through the high-pressure seawater outlet 12, and then is transported to the osmotic membrane for filtration after passing through a booster pump, and then the high-pressure concentrated brine 11 is depressurized to become low-pressure concentrated brine 12 and is discharged through the low-pressure concentrated brine outlet 32.

[0030] The above energy recovery device for seawater desalination has the following working steps:

[0031] S1, such as Figure 1 As shown, the pre-treated low-pressure seawater 10 enters the first pressure pipe 1 through the low-pressure seawater inlet 11, and the high-pressure concentrated brine 11 enters the concentrated brine switching pipe 3 and is guided into the first pressure pipe 1 filled with low-pressure seawater 10 through the third piston structure 6;

[0032] S2, the high-pressure concentrated brine 11 continuously pushes the first piston structure 4 to move in the direction of the first hydraulic switching valve 7. During the movement, the pressure of the high-pressure concentrated brine 11 is transmitted to the low-pressure seawater 10, and then the low-pressure seawater 10 is pressurized and discharged through the check valve provided in the high-pressure seawater outlet 12; at the same time, part of the pressurized seawater enters the first piston rod 42 through the water inlet hole 43, and is introduced into the first hydraulic switching valve through the water outlet hole 44; at this time, the first piston structure 4 compresses the elastic structure 71 in the first hydraulic switching valve 7 during the movement;

[0033] S3. When the piston block 41 with the water outlet hole 44 moves to between the two water inlets and outlets 72 of the first hydraulic switching valve 7, the high-pressure seawater 13 in the first hydraulic switching valve 7 enters the third hydraulic switching valve 9 through one of the water inlets and outlets 72 and the corresponding pipeline, and the high-pressure seawater 13 pushes the third piston rod to move downward for switching, and the piston located in the concentrated brine switching pipe 3 on the third piston rod moves accordingly, so that the channel for the high-pressure concentrated brine 11 to enter the first pressure-bearing pipe 1 is cut off; during the switching movement of the third piston rod, the seawater in the third hydraulic switching valve 9 is discharged into the second hydraulic switching valve 8 through the other water inlet and outlet 72 thereon; this part of the seawater is discharged through the water inlet and outlet 72 on the second hydraulic switching valve 8;

[0034] S4, after the high-pressure concentrated brine 11 is depressurized, the elastic structure 71 in the first hydraulic switching valve 7 rebounds, and with the injection of low-pressure seawater 10, the first piston structure 4 discharges the low-pressure concentrated brine 12 through one of the low-pressure concentrated brine outlets 32 during the return stroke; Figure 2 As shown, the high-pressure concentrated brine 11 entering the concentrated brine switching pipe 3 is introduced into the second pressure pipe 2 and pressurizes the low-pressure seawater 10 entering the second pressure pipe 2, and the circulation between the two pressure pipes repeats itself.

[0035] According to the test, a complete cycle is about 12 seconds. At this speed, the processing capacity of a single device is 350 cubic meters per hour or 8,400 cubic meters per day. In order to achieve higher output, multiple devices can be placed in parallel according to the on-site processing conditions.

[0036] The above is only a preferred embodiment of this patent and does not impose any form of limitation on this patent. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of this patent are within the scope of the technical solution of this patent.

Claims

1. An energy recovery device for seawater desalination, characterized in that: It comprises a first pressure-bearing pipe and a second pressure-bearing pipe arranged in parallel; one end of the two pressure-bearing pipes is vertically connected to a concentrated brine switching pipe at the same time, and the other end of the first pressure-bearing pipe is coaxially connected to a first hydraulic switching valve through a first piston structure, and the other end of the second pressure-bearing pipe is coaxially connected to a second hydraulic switching valve through a second piston structure; one side of the concentrated brine switching pipe is coaxially connected to a third hydraulic switching valve through a third piston structure; The concentrated brine switching pipe is provided with a high-pressure concentrated brine inlet and two upper and lower low-pressure concentrated brine outlets; the high-pressure concentrated brine inlet is located between the first pressure-bearing pipe and the second pressure-bearing pipe, and the two pressure-bearing pipes are located between the upper and lower low-pressure concentrated brine outlets; The first or second hydraulic switching valve transfers the high-pressure water flow energy of the corresponding pressure pipe to the third hydraulic switching valve, and realizes the waterway switching of the high-pressure concentrated brine in the concentrated brine switching pipe through the movement of the third piston structure; A low-pressure seawater inlet and a high-pressure seawater outlet are provided on the first and second pressure-bearing pipes at one end away from the concentrated brine switching pipe. The low-pressure seawater enters the corresponding pressure-bearing pipe through the low-pressure seawater inlet, and the high-pressure concentrated brine enters the concentrated brine switching pipe and is guided into the pressure-bearing pipe filled with low-pressure seawater through the third piston structure. The pressure of the high-pressure concentrated brine in the pressure-bearing pipe is transmitted to the low-pressure seawater, and the low-pressure seawater is pressurized and discharged through the high-pressure seawater outlet, and then transported to the osmotic membrane for filtration after passing through a booster pump. The high-pressure concentrated brine becomes low-pressure concentrated brine after the pressure is released, and is discharged through the low-pressure concentrated brine outlet; The first piston structure comprises two piston blocks located in the first hydraulic switching valve, the two piston blocks are spaced a certain distance apart and connected as a whole by a first piston rod, one end of the first piston rod is located in the first hydraulic switching valve, and the other end is located in the first pressure-bearing pipe, and the first piston rod located inside the first pressure-bearing pipe is provided with a plurality of rows of water inlet holes, and the seawater in the first pressure-bearing pipe enters the first piston rod through the water inlet holes, and is introduced into the first hydraulic switching valve through the first piston rod and the water outlet holes provided on the piston block close to the first pressure-bearing pipe; the second and first piston structures have the same structure; The first hydraulic switching valve is provided with two water inlets and outlets, and the distance between the two water inlets and outlets is smaller than the distance between the two piston blocks on the first piston structure; The structures of the second and first hydraulic switching valves are the same.

2. The energy recovery device for seawater desalination according to claim 1, characterized in that: The third piston structure comprises three piston blocks connected as a whole through a piston rod, one of the piston blocks is located in the third hydraulic switching valve, and the other two piston blocks are located in the concentrated brine switching pipe.

3. The energy recovery device for seawater desalination according to claim 2, characterized in that: An elastic structure in contact with the first piston structure is provided in the first hydraulic switching valve, and two water inlets and outlets spaced a certain distance apart are also provided on the third hydraulic switching valve.

4. The recovery method of the energy recovery device for seawater desalination according to claim 3, characterized in that: The working steps are as follows: S1, the pre-treated low-pressure seawater enters the first pressure-bearing pipe through the low-pressure seawater inlet, and the high-pressure concentrated brine enters the concentrated brine switching pipe and is guided by the third piston structure into the first pressure-bearing pipe filled with low-pressure seawater; S2, the high-pressure concentrated salt water continuously pushes the first piston structure to move in the direction of the first hydraulic switching valve. During the movement, the pressure of the high-pressure concentrated salt water is transmitted to the low-pressure seawater, and then the low-pressure seawater is pressurized and discharged through the check valve provided in the high-pressure seawater outlet; at the same time, part of the pressurized seawater enters the first piston rod through the water inlet hole, and is introduced into the first hydraulic switching valve through the water outlet hole; at this time, the first piston structure compresses the elastic structure in the first hydraulic switching valve during the movement; S3, when the piston block with the water outlet hole moves to between the two water inlets and outlets of the first hydraulic switching valve, the high-pressure seawater in the first hydraulic switching valve enters the third hydraulic switching valve through one of the water inlets and outlets and the corresponding pipeline, and the high-pressure seawater pushes the third piston rod to move downward for switching, and the piston located in the concentrated brine switching pipe on the third piston rod moves accordingly, and the channel for the high-pressure concentrated brine to enter the first pressure-bearing pipe is cut off; during the switching movement of the third piston rod, the seawater in the third hydraulic switching valve is discharged into the second hydraulic switching valve through the other water inlet and outlet thereon; this part of the seawater is discharged through the water inlet and outlet on the second hydraulic switching valve; S4, after the high-pressure concentrated brine is depressurized, the elastic structure in the first hydraulic switching valve rebounds, and with the injection of low-pressure seawater, the first piston structure discharges the low-pressure concentrated brine through one of the low-pressure concentrated brine outlets during the return stroke; The high-pressure concentrated brine entering the concentrated brine switching pipe is introduced into the second pressure pipe and pressurizes the low-pressure seawater entering the second pressure pipe, and the circulation between the two pressure pipes repeats itself.

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