Energy-saving seawater desalination treatment system
By adopting a combination scheme of variable frequency feeding pump and industrial frequency high-pressure pump in a large reverse osmosis seawater desalination system, and setting up a turbine energy recovery device before freshwater reverse osmosis, the problem of high system costs and insufficient energy saving is solved, and the goal of reducing investment costs and improving the energy saving effect of the system is achieved.
Patent Information
- Application Number
- CN202421811581.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-30
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-07-30
AI Technical Summary
In existing large reverse osmosis seawater desalination systems, the cost of the inverter of high-pressure pumps is high, resulting in increased system investment costs and insufficient energy saving.
A combination scheme of variable frequency feeding pump and industrial frequency high-pressure pump is adopted, and a turbine energy recovery device is set up before fresh water reverse osmosis, and energy recovery and reuse is carried out through the energy recovery branch pipeline and the turbine booster pump.
While meeting the system pressure adjustment needs, the system investment cost is reduced and the entire system is more energy-saving through energy recovery.
Smart Images
Figure CN222907630U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of seawater desalination, and specifically relates to an energy-saving seawater desalination processing system. Background Art
[0002] my country attaches great importance to the utilization of seawater. At present, the main seawater desalination processes suitable for industrialization are seawater reverse osmosis, low-temperature multi-effect distillation and multi-stage flash evaporation. Among them, seawater reverse osmosis is the most widely used in industry. Seawater reverse osmosis is generally set as a one-stage method, with a recovery rate of about 40% and a salt content of produced water of no more than 300 mg / L. The flow rate of the high-pressure pump used in reverse osmosis seawater desalination systems of different sizes is determined by the processing capacity determined during the design, and the pressure of the high-pressure pump is adjusted according to the membrane conditions, water quality, water temperature and other conditions. Therefore, in order to meet the requirements of operating pressure changes, the high-pressure pump of the seawater desalination system generally adopts a variable frequency pump.
[0003] However, for large-scale reverse osmosis desalination systems, with the continuous development of reverse osmosis desalination technology in my country, the output of a single reverse osmosis desalination unit has been continuously improved, and has now reached 35,000 tons / day. Correspondingly, the output of the high-pressure pump supporting the SWRO (reverse osmosis desalination unit) is also increasing, reaching thousands of tons / hour, and the head reaches about 6.0MPa. If a variable frequency pump is selected for the high-pressure pump, the inverter cost of the large-flow high-pressure pump is very high, which will greatly increase the system investment cost. Utility Model Content
[0004] The technical problem to be solved by the utility model is to provide an energy-saving seawater desalination treatment system to solve the problem of high cost of existing large-scale reverse osmosis seawater desalination systems, to reduce system investment while meeting the system pressure adjustment requirements, and to make the entire system more energy-efficient.
[0005] According to the technical scheme of the utility model, the utility model provides an energy-saving seawater desalination treatment system, including a SWRO water feed pump, a SWRO high-pressure pump, a reverse osmosis seawater desalination device, a fresh water reverse osmosis high-pressure pump and a fresh water reverse osmosis device, which are connected in sequence through pipelines from a water inlet end to a water production end, wherein the SWRO water feed pump is a variable frequency pump and the SWRO high-pressure pump is an industrial frequency pump; an energy recovery branch pipeline is connected to the pipeline between the SWRO water feed pump and the SWRO high-pressure pump, the other end of the energy recovery branch pipeline is connected to the pipeline between the SWRO high-pressure pump and the reverse osmosis seawater desalination device, and an energy recovery device and an energy recovery booster pump are connected to the energy recovery branch pipeline; the brine discharge end of the reverse osmosis seawater desalination device is connected to the brine drainage pipeline through the energy recovery device.
[0006] Furthermore, a turbine booster pump is connected between the reverse osmosis seawater desalination device and the fresh water reverse osmosis high-pressure pump, and the energy recovery device is connected to the concentrated brine drainage pipeline through the turbine booster pump.
[0007] Furthermore, the brine discharge end of the fresh water reverse osmosis device is connected to the water inlet side pipeline of the SWRO water pump through the brine recovery pipeline.
[0008] Compared with the prior art, the beneficial technical effects of the utility model are as follows:
[0009] The energy-saving seawater desalination treatment system of the utility model adopts a variable frequency water feed pump + industrial frequency high-pressure pump through the SWRO device, and further preferably sets a turbine energy recovery device before the fresh water reverse osmosis. Measures such as this enable the entire system to reduce system investment while meeting the system pressure adjustment requirements, and recover the concentrated water energy of the higher pressure of the SWRO, making the entire system more energy-efficient. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 It is a structural schematic diagram according to an embodiment of the utility model.
[0011] Description of reference numerals in the accompanying drawings:
[0012] 1. SWRO feed water pump; 2. SWRO high-pressure pump; 3. Reverse osmosis seawater desalination device; 4. Fresh water reverse osmosis high-pressure pump; 5. Fresh water reverse osmosis device; 6. Energy recovery branch pipeline; 7. Energy recovery device; 8. Energy recovery booster pump; 9. Brine drainage pipeline; 10. Turbine booster pump; 11. Brine recovery pipeline. DETAILED DESCRIPTION
[0013] The utility model provides an energy-saving seawater desalination treatment system to solve the problem of high cost of existing large-scale reverse osmosis seawater desalination systems. Specifically, the flow rate of the high-pressure pump used in reverse osmosis seawater desalination systems of different sizes is determined by the processing volume determined during the design, and the pressure of the high-pressure pump is adjusted and changed according to the membrane conditions, water quality, water temperature and other conditions. Therefore, in order to meet the requirements of operating pressure changes, the high-pressure pump of the seawater desalination system generally adopts a variable frequency pump. However, for large-scale reverse osmosis seawater desalination systems, the output of the high-pressure pump is thousands of tons / hour, and the head is ~6.0MPa. If the high-pressure pump adopts a variable frequency setting, the cost of the frequency converter is very high, which will increase the system investment cost. This solution is mainly aimed at reducing the system investment while meeting the system pressure adjustment requirements, and the entire system is more energy-efficient.
[0014] See also Figure 1, an energy-saving seawater desalination treatment system according to one embodiment of the utility model includes a SWRO water supply pump 1, a SWRO high-pressure pump 2, a reverse osmosis seawater desalination device 3, a freshwater reverse osmosis high-pressure pump 4 and a freshwater reverse osmosis device 5, which are connected in sequence from the water inlet end to the water production end through pipelines, wherein the SWRO water supply pump 1 is a variable frequency pump, and the SWRO high-pressure pump 2 is an industrial frequency pump. In this scheme, the SWRO water supply pump 1 is set as a variable frequency pump, and the SWRO high-pressure pump 2 adopts an industrial frequency pump. The outlet pressure of the SWRO high-pressure pump 2 is adjusted by adjusting the pressure of the SWRO water supply pump 1 to meet the system requirements, which can save system investment. In addition, a freshwater reverse osmosis device 5 can be set behind the reverse osmosis seawater desalination device 3 according to the seawater quality to improve the quality of the final product water. The freshwater reverse osmosis device 5 also needs to be equipped with a high-pressure pump to meet the pressure requirements of the membrane treatment.
[0015] More specifically, an energy recovery branch line 6 is connected to the pipeline between the SWRO feed water pump 1 and the SWRO high-pressure pump 2, and the other end of the energy recovery branch line 6 is connected to the pipeline between the SWRO high-pressure pump 2 and the reverse osmosis desalination device 3. The energy recovery branch line 6 is connected to an energy recovery device 7 and an energy recovery booster pump 8; the concentrated brine discharge end of the reverse osmosis desalination device 3 is connected to the concentrated brine drainage pipeline 9 through the energy recovery device 7. After the influent passes through the SWRO feed water pump 1 (and the filter), it is divided into two paths, one of which is the water inlet end of the energy recovery device 7 through the energy recovery branch line 6; the high-pressure concentrated brine discharged from the reverse osmosis desalination device 3 enters the concentrated brine end of the energy recovery device 7; in the energy recovery device 7, the concentrated brine end and the water inlet end exchange energy, so that the energy of the high-pressure concentrated brine is converted into the energy of the influent, and then the concentrated brine is discharged; the influent output of the energy recovery device 7 is further output through the energy recovery booster pump 8, merged with the water output from the SWRO high-pressure pump 2, and enters the reverse osmosis desalination device 3.
[0016] Furthermore, since the SWRO feed water pump 1 is also responsible for supplying water to the energy recovery device 7, if the water supply pressure is high, the concentrated water discharge pressure after the energy recovery device 7 will also increase, and the direct discharge of this part of water will also cause energy waste. Therefore, it is proposed to set a turbine energy recovery device before the fresh water reverse osmosis to recycle this part of energy. Specifically, a turbine booster pump 10 is also connected between the reverse osmosis seawater desalination device 3 and the fresh water reverse osmosis high-pressure pump 4, and the energy recovery device 7 is connected to the concentrated brine drainage pipeline 9 through the turbine booster pump 10. Among them, the turbine booster pump 10 is a mechanical device that converts the pressure energy of the seawater reverse osmosis concentrated water into mechanical energy. The residual pressure of the concentrated water in the process can be recovered and reused by using a hydraulic turbine, and converted into mechanical energy to drive mechanical equipment to achieve energy saving. The main principle of the turbine booster pump 10 is that the turbine and the pump are coaxially arranged, so that no electric drive is required, and the concentrated brine output by the energy recovery device 7 drives the pump to pressurize the fresh water output by the reverse osmosis desalination device 3; because it can recover energy before the concentrated brine is discharged and pressurize the fresh water on the upstream side of the freshwater reverse osmosis device 5, it can also be called a turbine energy recovery device. Through the above measures, the utility model can greatly improve the energy saving effect of the entire reverse osmosis desalination system.
[0017] Furthermore, the brine discharge end of the fresh water reverse osmosis device 5 is connected to the water inlet side pipeline of the SWRO water pump 1 through the brine recovery pipeline 11, so that the brine discharged from the fresh water reverse osmosis device 5 returns to the water inlet end for reuse.
[0018] In summary, the energy-saving seawater desalination treatment system of the utility model adopts a variable frequency water feed pump + industrial frequency high-pressure pump through the SWRO device, and further preferably sets a turbine energy recovery device before the fresh water reverse osmosis, etc., so that the whole system can reduce the system investment while meeting the system pressure adjustment requirements, and recovers the concentrated water energy of the higher pressure of SWRO, making the whole system more energy-efficient.
Claims
1. An energy-saving seawater desalination system, characterized in that: The invention comprises a SWRO water supply pump (1), a SWRO high-pressure pump (2), a reverse osmosis seawater desalination device (3), a fresh water reverse osmosis high-pressure pump (4) and a fresh water reverse osmosis device (5) which are connected in sequence through pipelines from a water inlet end to a water production end, wherein the SWRO water supply pump (1) is a variable frequency pump and the SWRO high-pressure pump (2) is an industrial frequency pump; an energy recovery branch pipeline (6) is connected to the pipeline between the SWRO water supply pump (1) and the SWRO high-pressure pump (2); the other end of the energy recovery branch pipeline (6) is connected to the pipeline between the SWRO high-pressure pump (2) and the reverse osmosis seawater desalination device (3); an energy recovery device (7) and an energy recovery booster pump (8) are connected to the energy recovery branch pipeline (6); and the concentrated brine discharge end of the reverse osmosis seawater desalination device (3) is connected to the concentrated brine drainage pipeline (9) through the energy recovery device (7).
2. The energy-saving seawater desalination system according to claim 1, characterized in that: A turbine booster pump (10) is also connected between the reverse osmosis seawater desalination device (3) and the fresh water reverse osmosis high-pressure pump (4), and the energy recovery device (7) is connected to the concentrated brine drainage pipeline (9) via the turbine booster pump (10).
3. The energy-saving seawater desalination system according to claim 1 or 2, characterized in that: The concentrated brine discharge end of the fresh water reverse osmosis device (5) is connected to the water inlet side pipeline of the SWRO water supply pump (1) through a concentrated brine recovery pipeline (11).