Off-grid type secondary seawater desalination treatment system

Abstract

The utility model discloses an off-network type secondary seawater desalination treatment system which comprises a primary reverse osmosis seawater desalination device, a turbine type booster pump and a secondary reverse osmosis device which are sequentially connected through a pipeline, wherein the fresh water output end of the first-stage reverse osmosis seawater desalination device is connected with the input end of the second-stage reverse osmosis device through the power output side of the turbine type booster pump, and the fresh water output end of the second-stage reverse osmosis device is connected with a produced water output pipeline; the strong brine discharge end of the first-stage reverse osmosis seawater desalination device is connected with a first strong brine energy recovery pipeline and a second strong brine energy recovery pipeline, the first strong brine energy recovery pipeline is internally connected with an energy recovery device, and the second strong brine energy recovery pipeline is connected with the power input side of the turbine type booster pump. According to the scheme, concentrated water pressure of the first-stage reverse osmosis seawater desalination device is converted into mechanical energy to pressurize inlet water of the second-stage reverse osmosis device, electric equipment can be reduced, and the seawater desalination device is more suitable for a seawater desalination system with new energy as energy supply.

Description

Technical Field

[0001] The utility model belongs to the technical field of seawater desalination, and particularly relates to an off-grid type two-stage seawater desalination treatment system. Background Art

[0002] China attaches great importance to the work of seawater utilization. At present, the seawater desalination processes suitable for industrialization mainly include seawater reverse osmosis method, low-temperature multi-effect distillation method and multi-stage flash distillation method. Among them, the most widely used is the seawater reverse osmosis method. The seawater reverse osmosis method is generally set as a single stage, with a recovery rate of about 40% and a salt content of about 300 mg / L in the produced water. With the increasing requirements for product water quality, a two-stage reverse osmosis device can be set behind the single-stage seawater reverse osmosis according to the seawater quality to improve the quality of the final product water. A high-pressure pump needs to be set for the two-stage reverse osmosis device to meet the treatment requirements.

[0003] In recent years, the combination of new energy such as wind and light and seawater desalination technology has been increasingly mentioned and emphasized. However, the biggest feature of new energy such as wind and light is its instability and large volatility. Once fluctuations occur, all electrical equipment needs to be adjusted. How the reverse osmosis seawater desalination device adapts to the volatility of new energy is a problem facing people. The current main solutions include setting energy storage devices, reducing the setting of electrical equipment, and increasing the variable load capacity of equipment.

[0004] Especially for off-grid seawater desalination systems in islands and other areas, the consideration of energy-saving effects and construction space costs and economic costs is more important. In the existing solutions, the high-pressure pump for two-stage reverse osmosis needs to be powered, and its adaptability to the instability of new energy is poor. Therefore, a new process solution is needed to better apply to the off-grid system. Summary of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide an off-grid type two-stage seawater desalination treatment system, which solves the problems of weak adaptability to new energy power supply and poor energy-saving effect in the existing solutions. By replacing the high-pressure pump for two-stage reverse osmosis with a turbine type booster pump, the number of electrical equipment is reduced, thereby reducing the fluctuating operation, so as to improve the applicability of the membrane method seawater desalination device to new energy, and provide a new technical idea for using new energy to produce high-quality seawater desalinated water.

[0006] According to the technical solution of the present utility model, the present utility model provides an off-grid type secondary seawater desalination treatment system, which includes a first-stage reverse osmosis seawater desalination device, a turbine type booster pump, and a second-stage reverse osmosis device that are sequentially connected through pipelines from the water inlet end to the water production end. Among them, the fresh water output end of the first-stage reverse osmosis seawater desalination device is connected to the input end of the second-stage reverse osmosis device through the power output side of the turbine type booster pump, and the fresh water output end of the second-stage reverse osmosis device is connected to the water production output pipeline; the concentrated brine discharge end of the first-stage reverse osmosis seawater desalination device is connected with a first concentrated brine energy recovery pipeline and a second concentrated brine energy recovery pipeline. An energy recovery device is connected in the first concentrated brine energy recovery pipeline, and the second concentrated brine energy recovery pipeline is connected to the power input side of the turbine type booster pump.

[0007] Further, a first-stage pump booster pipeline and a first-stage energy recovery booster pipeline are arranged in parallel at the input end of the first-stage reverse osmosis seawater desalination device. A booster pump valve and a first-stage booster pump are connected in series in the first-stage pump booster pipeline, and an energy recovery valve, an energy recovery device, and an energy recovery booster pump are connected in series in the first-stage energy recovery booster pipeline.

[0008] Further, the concentrated brine discharge end of the second-stage reverse osmosis device is connected to the total water inlet pipeline on the upstream side of the first-stage pump booster pipeline and the first-stage energy recovery booster pipeline through a concentrated brine recovery pipeline.

[0009] Further, a first concentrated brine valve is connected to the first concentrated brine energy recovery pipeline, and a second concentrated brine valve is connected to the second concentrated brine energy recovery pipeline.

[0010] Further, the ends of both the first concentrated brine energy recovery pipeline and the second concentrated brine energy recovery pipeline are connected to the concentrated brine drainage pipeline.

[0011] Compared with the prior art, the beneficial technical effects of the present utility model are as follows:

[0012] The off-grid type secondary seawater desalination treatment system of the present utility model uses the turbine type booster pump as the high-pressure pump of the second-stage reverse osmosis device, converts the pressure of the concentrated water of the first-stage reverse osmosis seawater desalination device into mechanical energy to boost the water inlet of the second-stage reverse osmosis device, rather than using electrical energy for boosting. Through these measures, the number of electrical equipment can be reduced, and it is more suitable for the reverse osmosis seawater desalination system powered by new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural diagram according to an embodiment of the present utility model.

[0014] Explanation of the reference numerals in the drawings:

[0015] 1. First-stage reverse osmosis seawater desalination device; 2. Turbine booster pump; 3. Second-stage reverse osmosis device; 4. Product water output pipeline; 5. First energy recovery pipeline for concentrated brine; 6. Second energy recovery pipeline for concentrated brine; 7. Energy recovery device; 8. First-stage pump booster pipeline; 9. First-stage energy recovery booster pipeline; 10. Booster pump valve; 11. First-stage booster pump; 12. Energy recovery valve; 13. Energy recovery booster pump; 14. Concentrated brine recovery pipeline; 15. Total inlet pipeline; 16. First concentrated brine valve; 17. Second concentrated brine valve; 18. Concentrated brine drainage pipeline. Detailed implementation mode

[0016] The present utility model provides an off-grid second-stage seawater desalination treatment system, which solves the problems of weak adaptability to new energy power supply and poor energy-saving effect in the existing solutions. By replacing the high-pressure pump of the second-stage reverse osmosis with a turbine booster pump, the number of power-consuming devices is reduced, thereby reducing fluctuating operations, so as to improve the applicability of the membrane method seawater desalination device to new energy, and provide a new technical idea for using new energy to produce high-quality seawater desalinated water.

[0017] Please refer to Figure 1 , an off-grid second-stage seawater desalination treatment system according to an embodiment of the present utility model, includes a first-stage reverse osmosis seawater desalination device 1, a turbine booster pump 2, and a second-stage reverse osmosis device 3 that are sequentially connected through pipelines from the water inlet end to the water production end. Among them: both the first-stage reverse osmosis seawater desalination device 1 and the second-stage reverse osmosis device 3 have an input end, a fresh water output end, and a concentrated brine output end; the turbine booster pump 2 is a mechanical device that converts the pressure energy of seawater reverse osmosis concentrated brine into mechanical energy, and can also be called a turbine energy recovery device. The main principle is that the turbine and the pump are coaxially arranged. One side (the lower side in the figure) is the power input side, and the hydraulic turbine can recover the residual pressure of the seawater reverse osmosis concentrated brine in the process flow. On the power output side (the upper side in the figure), it is converted into mechanical energy to drive the mechanical device (pump) to boost the water pressure. This process does not require additional electricity and can achieve the effect of reusing the residual pressure and saving energy.

[0018] The fresh water output end of the first-stage reverse osmosis seawater desalination device 1 is connected to the input end of the second-stage reverse osmosis device 3 through the power output side of the turbine booster pump 2. The fresh water output end of the second-stage reverse osmosis device 3 is connected to the product water output pipeline 4 (i.e., the product water end), so as to output fresh water with higher quality after two-stage reverse osmosis. The concentrated brine discharge end of the first-stage reverse osmosis seawater desalination device 1 is branched and connected with a first concentrated brine energy recovery pipeline 5 and a second concentrated brine energy recovery pipeline 6. An energy recovery device 7 is connected in the first concentrated brine energy recovery pipeline 5, and the second concentrated brine energy recovery pipeline 6 is connected to the power input side of the turbine booster pump 2, so as to recover the energy of the concentrated brine in two ways. The ends of the first concentrated brine energy recovery pipeline 5 and the second concentrated brine energy recovery pipeline 6 are both connected to a concentrated brine drainage pipeline 18, for example, to uniformly discharge the concentrated brine (or discharge it into other water use systems according to needs).

[0019] Preferably, a first concentrated brine valve 16 is connected to the first concentrated brine energy recovery pipeline 5, and a second concentrated brine valve 17 is connected to the second concentrated brine energy recovery pipeline 6, so as to be able to adjust the distribution ratio between the two energy recovery methods according to needs.

[0020] One side of the energy recovery device 7 (the left side in the figure) is the raw water side, and the other side (the right side in the figure) is the concentrated brine side, which are respectively used for the passage of raw water (i.e., influent, seawater) and the high-pressure concentrated brine discharged from the first-stage reverse osmosis seawater desalination device 1, so as to transfer the energy recovery of the concentrated brine to the influent. An inlet pump booster pipeline 8 and an inlet energy recovery booster pipeline 9 are arranged in parallel at the input end of the first-stage reverse osmosis seawater desalination device 1. A booster pump valve 10 and a first-stage booster pump 11 are connected in series in the inlet pump booster pipeline 8, and an energy recovery valve 12, an energy recovery device 7 and an energy recovery booster pump 13 are connected in series in the inlet energy recovery booster pipeline 9. Thus, it can be selected according to needs to boost all or a certain proportion of the influent in the total influent pipeline 15 by the first-stage booster pump 11 to meet the requirements of the first-stage reverse osmosis seawater desalination device 1, and the remaining part of the influent is boosted by the energy recovery device 7 and the energy recovery booster pump 13. The energy required to be provided by the energy recovery booster pump 13 is significantly less than that of the first-stage booster pump 11, so as to play an energy-saving role.

[0021] Preferably, the concentrated brine discharge end of the second-stage reverse osmosis device 3 is connected to the total influent pipeline 15 upstream of the inlet pump booster pipeline 8 and the inlet energy recovery booster pipeline 9 through a concentrated brine recovery pipeline 14, so that this part of the concentrated brine is not directly discharged but recycled, that is, used as influent for desalination again.

[0022] In summary, the off-grid type two-stage seawater desalination treatment system of the present utility model sets a two-stage reverse osmosis device behind the first-stage reverse osmosis seawater desalination device, and uses a turbine type booster pump as the high-pressure pump for the two-stage reverse osmosis to increase the inlet water pressure, meet the inlet water requirements of the two-stage reverse osmosis device, and solve the disadvantages that the use of a high-pressure pump for two-stage reverse osmosis requires power supply and has a poor adaptability to the instability of new energy. During operation, seawater passes through the first-stage reverse osmosis seawater desalination device, and the concentrated water is divided into two paths, one path goes to the energy recovery device, and the other path goes to the turbine type booster pump. The hydraulic turbine can be used to recover and utilize the pressure of the concentrated water from the first-stage seawater reverse osmosis device, convert it into mechanical energy to drive the turbine type booster pump to pressurize the inlet water for the two-stage reverse osmosis, and meet the inlet water requirements of the two-stage reverse osmosis device. Through these measures, the number of electrical equipment can be reduced, and it is more suitable for the reverse osmosis seawater desalination system with new energy as the energy supply. It should be noted that each device element in this solution can adopt existing technologies, and furthermore, the above operation process is preferably automatically operated through automatic valves, instruments, control systems, etc., without manual operation.

Claims

1. An off-grid secondary seawater desalination treatment system, characterized in that, It includes a first-stage reverse osmosis seawater desalination device (1), a turbine booster pump (2), and a second-stage reverse osmosis device (3) that are sequentially connected through pipelines from the water inlet end to the water production end. The fresh water output end of the first-stage reverse osmosis seawater desalination device (1) is connected to the input end of the second-stage reverse osmosis device (3) through the power output side of the turbine booster pump (2), and the fresh water output end of the second-stage reverse osmosis device (3) is connected to the water production output pipeline (4); the concentrated brine discharge end of the first-stage reverse osmosis seawater desalination device (1) is connected with a first concentrated brine energy recovery pipeline (5) and a second concentrated brine energy recovery pipeline (6). An energy recovery device (7) is connected in the first concentrated brine energy recovery pipeline (5), and the second concentrated brine energy recovery pipeline (6) is connected to the power input side of the turbine booster pump (2).

2. The off-grid secondary seawater desalination treatment system according to claim 1, wherein A first-stage pump booster pipeline (8) and a first-stage energy recovery booster pipeline (9) are arranged in parallel at the input end of the first-stage reverse osmosis seawater desalination device (1). A booster pump valve (10) and a first-stage booster pump (11) are connected in series in the first-stage pump booster pipeline (8), and an energy recovery valve (12), the energy recovery device (7), and an energy recovery booster pump (13) are connected in series in the first-stage energy recovery booster pipeline (9).

3. The off-grid secondary seawater desalination treatment system according to claim 2, characterized in that, The concentrated brine discharge end of the second-stage reverse osmosis device (3) is connected to the total water inlet pipeline (15) upstream of the first-stage pump booster pipeline (8) and the first-stage energy recovery booster pipeline (9) through a concentrated brine recovery pipeline (14).

4. The off-grid secondary seawater desalination treatment system according to any one of claims 1-3, characterized in that, A first concentrated brine valve (16) is connected to the first concentrated brine energy recovery pipeline (5), and a second concentrated brine valve (17) is connected to the second concentrated brine energy recovery pipeline (6).

5. The off-grid type secondary seawater desalination treatment system according to any one of claims 1-3, characterized in that, The ends of the first concentrated brine energy recovery pipeline (5) and the second concentrated brine energy recovery pipeline (6) are both connected to a concentrated brine drainage pipeline (18).

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