Steam-driven reverse osmosis seawater desalination system

Abstract

The utility model relates to the technical field of seawater desalination, in particular to a steam-driven reverse osmosis seawater desalination system. The system comprises a steam power subsystem and a seawater desalination subsystem, the steam power subsystem comprises a steam generating device, a steam turbine, a surface type condenser and a condensate pump; the seawater desalination subsystem comprises a steam-driven high-pressure pump, an energy recovery device, a reverse osmosis device, a seawater booster pump and a seawater lifting pump; the seawater lifting pump is connected with the surface type condenser; the surface type condenser is connected with the condensate pump; the condensate pump is connected with the steam generating device; the steam generating device is connected with the steam turbine; according to the utility model, heat energy-electric energy-mechanical energy three-stage energy conversion of a conventional seawater desalination technology is simplified into heat energy-mechanical energy two-stage energy conversion, so that the energy conversion links are reduced, the energy utilization efficiency is improved, dead steam of the steam power subsystem is utilized to preheat seawater, the energy utilization efficiency is further improved, and the energy utilization cost is reduced. And high-efficiency desalination treatment of seawater is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of seawater desalination, in particular to a steam-driven reverse osmosis seawater desalination system. Background Art

[0002] Seawater desalination technology has always been one of the important ways to solve the global water shortage, especially in arid areas, desert areas and coastal areas. Seawater desalination technology refers to the technology of removing salt and other impurities from seawater and converting it into fresh water. At present, seawater desalination technologies mainly include distillation, electrodialysis, reverse osmosis membrane, etc. Among them, reverse osmosis membrane has become the mainstream technology for seawater desalination due to its high efficiency and stable performance. With its high efficiency and stable performance, it has been widely used around the world. However, with the in-depth development and application promotion of technology, reverse osmosis seawater desalination technology also faces some challenges and bottlenecks.

[0003] First of all, from a cost perspective, the water production cost of reverse osmosis desalination technology is still relatively high. This is mainly due to the high energy consumption of the system. In the reverse osmosis process, the high-pressure pump, as the core equipment of the system, consumes a lot of electricity to drive seawater through the reverse osmosis membrane. Although this configuration simplifies the system structure, it limits the use of other non-electrical energy such as solar heat, making the energy consumption of the entire system high. Therefore, how to reduce system energy consumption and improve energy utilization efficiency is an important issue that needs to be solved in reverse osmosis desalination technology.

[0004] Secondly, from the perspective of technology application, there is still a certain distance between the economic indicators of the existing reverse osmosis desalination technology and the general expectations of the society. This is mainly reflected in the water production cost, energy consumption and water quality. With the increasing shortage of global water resources, countries are increasingly in need of desalination technology. However, the desalination technology in many countries and regions still has problems such as high cost, high energy consumption and unstable water quality, which makes it difficult to meet the needs of the society. Therefore, how to further improve the economy and environmental protection of reverse osmosis desalination technology is a key issue that needs to be solved in the promotion and application of this technology.

[0005] In addition, the reverse osmosis membrane method faces some other problems during its application. For example, the reverse osmosis membrane is easily affected by pollution and scaling, resulting in a decrease in water production and a decrease in desalination rate. This is mainly due to the deposition and aggregation of impurities such as microorganisms, organic matter and inorganic salts in seawater on the membrane surface. In order to solve this problem, the reverse osmosis membrane needs to be cleaned and replaced regularly, which increases the operation and maintenance costs of the system. At the same time, the limited lifespan and anti-pollution ability of the reverse osmosis membrane are also one of the important factors restricting the widespread application of this technology.

[0006] In summary, reverse osmosis desalination technology, as an important means of water resource development, plays an important role in solving the global water shortage problem. However, this technology still faces problems such as cost and energy consumption in practical application. Utility Model Content

[0007] In order to solve the problems existing in the prior art, the utility model provides a steam-driven reverse osmosis seawater desalination system, which can directly utilize thermal energy, replace the three-level energy conversion of thermal energy-electrical energy-mechanical energy with the two-level energy conversion of thermal energy-mechanical energy, and use the heat of exhaust steam to heat seawater, so as to facilitate the expansion of the utilization of new energy technologies such as solar thermal energy, and achieve higher energy utilization efficiency and lower comprehensive water production cost than the prior art.

[0008] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0009] The utility model provides a steam-driven reverse osmosis seawater desalination system, comprising a steam power subsystem and a seawater desalination subsystem; the steam power subsystem comprises a steam generating device, a steam turbine, a surface condenser and a condensate pump; the seawater desalination subsystem comprises a steam-driven high-pressure pump, an energy recovery device, a reverse osmosis device, a seawater booster pump and a seawater lift pump;

[0010] The seawater lifting pump is connected to the surface condenser; the surface condenser is connected to the condensate pump; the condensate pump is connected to the steam generating device; the steam generating device is connected to the steam turbine; the steam turbine is respectively connected to the surface condenser and the steam-driven high-pressure pump; the steam-driven high-pressure pump is connected to the reverse osmosis device; the reverse osmosis device is connected to the seawater boosting pump; the energy recovery device is respectively connected to the seawater boosting pump and the surface condenser.

[0011] Preferably, the steam generating device is an oil-fired boiler, a gas-fired boiler or a coal-fired boiler.

[0012] Preferably, the seawater desalination system further comprises a solar thermal collector; the solar thermal collector is connected to the condensate pump and the steam turbine respectively.

[0013] Preferably, the solar collector is a trough collector or a linear Fresnel collector.

[0014] Preferably, the energy recovery device is a centrifugal device or a positive displacement device.

[0015] Preferably, the reverse osmosis device adopts a single-stage, multi-stage or multi-stage configuration.

[0016] Preferably, the condensate pump, seawater booster pump and seawater lift pump are pneumatically driven.

[0017] Preferably, the condensate pump, seawater booster pump and seawater lift pump are electrically driven.

[0018] Preferably, the cooling water inlet mode of the surface condenser may be consistent with or opposite to the flow direction of the shell side exhaust steam, that is, steam-water co-current or steam-water counter-current.

[0019] Preferably, the surface condenser is used to heat the inlet water of the seawater desalination subsystem.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] The utility model provides a steam-driven reverse osmosis seawater desalination system, which simplifies the conventional seawater desalination technology's three-level energy conversion of heat energy-electric energy-mechanical energy (heat energy-electric energy conversion is carried out in a power plant) into a two-level energy conversion of heat energy-mechanical energy by arranging a steam turbine and a steam-driven high-pressure pump, thereby reducing energy conversion links and improving energy utilization efficiency; the exhausted steam of the steam power subsystem is used for pre-heating seawater, increasing the output of the seawater desalination subsystem, and further improving the overall energy efficiency of the system.

[0022] Furthermore, for areas with good solar energy resources, solar collectors can be used to produce high-temperature and high-pressure steam, which can completely or partially replace the steam generating device, thereby reducing the water production cost of the seawater desalination system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are for explanation purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only for illustration purposes to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention.

[0024] In the attached picture:

[0025] Figure 1 A schematic diagram of the structure of a steam-driven reverse osmosis seawater desalination system provided by the utility model;

[0026] In the figure: 1-steam generating device; 2-steam turbine; 3-surface condenser; 4-condensate pump; 5-steam driven high pressure pump; 6-energy recovery device; 7-reverse osmosis device; 8-seawater booster pump; 9-seawater lifting pump; 10-solar collector; 11-seawater raw water; 12-seawater desalination to produce demineralized water; 13-seawater desalination to produce concentrated water. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0028] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0029] like Figure 1 As shown, the utility model provides a steam-driven reverse osmosis seawater desalination system, comprising a steam power subsystem and a seawater desalination subsystem; the steam power subsystem comprises a steam generating device 1, a steam turbine 2, a surface condenser 3 and a condensate pump 4; the seawater desalination subsystem comprises a steam-driven high-pressure pump 5, an energy recovery device 6, a reverse osmosis device 7, a seawater booster pump 8 and a seawater lift pump 9; the seawater lift pump 9 is connected to the surface condenser 3; the surface condenser 3 is connected to the condensate pump 4; the condensate pump 4 is connected to the steam generating device 1; the steam generating device 1 is connected to the steam turbine 2; the steam turbine 2 is respectively connected to the surface condenser 3 and the steam-driven high-pressure pump 5; the steam-driven high-pressure pump 5 is connected to the reverse osmosis device 7; the reverse osmosis device 7 is connected to the seawater booster pump 8; the energy recovery device 6 is respectively connected to the seawater booster pump 8 and the surface condenser 3.

[0030] The working fluid of the steam power subsystem is desalted water, which is lifted and transported to the steam generating device 1 by the condensate pump. The desalted water is heated in the steam generating device 1 by an oil-fired boiler, a gas-fired boiler or a coal-fired boiler and converted into high-temperature and high-pressure steam. These high-temperature and high-pressure steams are then sent to the steam turbine 2 to expand and work, driving it to rotate and generate power, and then driving the steam-driven high-pressure pump 5 of the seawater desalination subsystem to rotate, providing the main power required by the seawater desalination subsystem. The exhaust steam after the steam turbine 2 works is discharged into the surface condenser 3 for cooling. These exhaust steams are cooled in the surface condenser 3 and recondensed into desalted water, and are transported back to the steam generating device 1 through the condensate pump 4 to enter the next round of thermal cycle; the desalted water is used as a working fluid in the steam power subsystem for closed circulation, and the loss is close to zero. A small amount of loss can be supplemented by the desalted water produced by the seawater desalination subsystem. The raw water of the seawater desalination subsystem is used as the cooling water source of the surface condenser 3 to condense the steam exhausted by the steam turbine 2 after work. The raw water is preheated to a certain temperature. The higher inlet water temperature can effectively improve the output of the seawater desalination subsystem and further improve the overall energy efficiency of the system.

[0031] Furthermore, in order to reduce the water production cost of the seawater desalination system, new energy equipment such as a solar thermal collector 10 can be introduced into the steam power subsystem, and the solar thermal collector 10 is connected to the condensate pump 4 and the steam turbine 2 respectively. The solar thermal collector 10 can use the free solar heat during the day to produce steam, completely or partially replace the steam generating device 1, and reduce fossil energy consumption. At this time, the steam generating device 1 can be used as a backup and supplement to the solar thermal collector 10 to ensure the all-weather production capacity of the system.

[0032] The treatment object of the seawater desalination subsystem is raw seawater 11 that has been pretreated or not, but meets the water quality requirements of the seawater desalination subsystem. The raw seawater 11 is first transported to the surface condenser 3 as a cooling water source through the seawater boost pump 9, and used as a cold source to cool the exhausted steam of the steam turbine 2 after work. The temperature of the seawater after passing through the surface condenser 3 increases, and the higher water temperature is conducive to the improvement of the subsequent reverse osmosis treatment output. One of the seawaters after the temperature increase pretreatment enters the reverse osmosis device 7 under the transportation action of the steam-driven high-pressure pump 5. By using the separation effect of the reverse osmosis membrane assembly, a part of the effluent water becomes the desalinated water 12 produced by seawater desalination, which is output to the system as the final product; the other part of the effluent with a higher salt content enters the energy recovery device 6. After recovering the pressure energy, the lower pressure desalinated concentrated water 13 is output outside the system as a by-product. The energy recovery device 6 transfers the recovered energy to the other seawater after the temperature increase pretreatment, and after the seawater booster pump 8 replenishes the pressure, it enters the reverse osmosis device 7 for treatment. In addition to the steam-driven high-pressure pump 5, other pump equipment such as the seawater lifting pump 9, the seawater booster pump 8 and the condensate pump 4 can also be driven by steam or electricity. Steam drive can reduce system power consumption. Electric drive can provide stable and powerful power output to meet the power requirements of various pump equipment.

[0033] Among them, the water inlet mode of the cooling water of the surface condenser 3 can be consistent with or opposite to the flow direction of the shell side exhaust steam, that is, steam-water co-current mode or steam-water counter-current mode; when the flow direction of the cooling water is consistent with that of the shell side exhaust steam, the resistance of the fluid flow can be reduced, thereby improving the heat exchange efficiency, which is suitable for some occasions that are sensitive to flow resistance; when the flow direction of the cooling water is opposite to that of the shell side exhaust steam, the heat exchange efficiency can be improved due to the increase in temperature gradient. The counter-current mode can usually provide a more uniform heat exchange effect and help reduce the deposition of dirt on the surface of the heat exchanger.

[0034] The solar thermal collector 10 can be a trough collector or a linear Fresnel collector. The energy recovery group device 6 can be a centrifugal device or a positive displacement device or other types of devices.

[0035] The reverse osmosis device 7 can be configured in a variety of forms, such as single-stage, multi-stage or multi-stage, and the configuration form can be flexibly selected according to different water qualities and treatment requirements. The single-stage configuration is suitable for simple filtration and desalination needs, while the multi-stage or multi-stage configuration can provide a higher level of treatment effect and greater production capacity. In addition, the multi-stage configuration can also achieve higher energy recovery efficiency through cascading.

[0036] As long as the first-stage high-pressure pump or each stage of high-pressure pumps is steam-driven and driven by the steam generated by the steam power subsystem, or the surface condenser 3 of the steam power subsystem is used to preheat the seawater, it should be regarded as within the protection scope of the present utility model.

[0037] The steam power subsystem described in the utility model is associated with the seawater desalination subsystem at the steam-driven high-pressure pump 5 and the surface condenser 3. The steam-driven high-pressure pump 5 is the device with the largest power consumption in the seawater desalination system. In the utility model, the driving mode of the high-pressure water pump with large power consumption is changed from electric motor drive to steam turbine drive, and the power is provided by the high-temperature and high-pressure steam generated by the steam power subsystem instead of being completed by power from the power grid, thereby greatly reducing the power consumption of the system. The power of the current power grid is usually produced in a thermal power plant by burning traditional fossil fuels, and its conversion itself has a certain efficiency loss. In the process of uploading the power to the power grid system and then downloading it to the seawater desalination plant, a part of the line loss will inevitably be generated. Therefore, from the perspective of energy utilization, the two-stage energy conversion of thermal energy-mechanical energy in the utility model has a higher comprehensive energy utilization efficiency than the three-stage energy conversion of thermal energy-electrical energy-mechanical energy in conventional technology. In addition, the use of the exhaust steam heat of the steam power subsystem to preheat the water in the seawater desalination subsystem can also obtain additional output increments, which can effectively improve the operating performance of the system in cold winter and has a high value of promotion and application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

Claims

1. A steam-driven reverse osmosis seawater desalination system, characterized in that: It comprises a steam power subsystem and a seawater desalination subsystem; the steam power subsystem comprises a steam generating device (1), a steam turbine (2), a surface condenser (3) and a condensate pump (4); the seawater desalination subsystem comprises a steam-driven high-pressure pump (5), an energy recovery device (6), a reverse osmosis device (7), a seawater boosting pump (8) and a seawater lifting pump (9); The seawater boost pump (9) is connected to the surface condenser (3); the surface condenser (3) is connected to the condensate pump (4); the condensate pump (4) is connected to the steam generating device (1); the steam generating device (1) is connected to the steam turbine (2); the steam turbine (2) is respectively connected to the surface condenser (3) and the steam-driven high-pressure pump (5); the steam-driven high-pressure pump (5) is connected to the reverse osmosis device (7); the reverse osmosis device (7) is connected to the seawater boost pump (8); the energy recovery device (6) is respectively connected to the seawater boost pump (8) and the surface condenser (3).

2. A steam-driven reverse osmosis seawater desalination system according to claim 1, characterized in that: The steam generating device (1) is an oil-fired boiler, a gas-fired boiler or a coal-fired boiler.

3. The steam-driven reverse osmosis seawater desalination system according to claim 1, characterized in that: The seawater desalination system further comprises a solar thermal collector (10); the solar thermal collector (10) is respectively connected to a condensate pump (4) and a steam turbine (2).

4. A steam-driven reverse osmosis seawater desalination system according to claim 3, characterized in that: The solar thermal collector (10) is a trough collector or a linear Fresnel collector.

5. The steam-driven reverse osmosis seawater desalination system according to claim 1, characterized in that: The energy recovery device (6) is a centrifugal device or a positive displacement device.

6. The steam-driven reverse osmosis seawater desalination system according to claim 1, characterized in that: The reverse osmosis device (7) is configured in a single-stage, multi-stage or multi-section manner.

7. The steam-driven reverse osmosis seawater desalination system according to claim 1, characterized in that: The condensate pump (4), the seawater booster pump (8) and the seawater lifting pump (9) are steam-driven.

8. The steam-driven reverse osmosis seawater desalination system according to claim 1, characterized in that: The condensate pump (4), the seawater booster pump (8) and the seawater lifting pump (9) are electrically driven.

9. The steam-driven reverse osmosis seawater desalination system according to claim 1, characterized in that: The cooling water inlet mode of the surface condenser (3) can be consistent with or opposite to the flow direction of the shell side exhaust steam, that is, steam-water co-current mode or steam-water counter-current mode.

10. The steam-driven reverse osmosis seawater desalination system according to claim 1, characterized in that: The surface condenser (3) is used to heat the inlet water of the seawater desalination subsystem.

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