A seawater desalination unit

Abstract

The present invention discloses a seawater desalination unit, which includes a seawater spraying section, a condensation section, a dehumidification section, a preheating section and a heat exchange section. The seawater inlet pipeline of the seawater spraying section passes through the preheating section and the heat exchange section. This seawater desalination unit can make full use of waste heat resources and produce fresh water through air humidification and condensation dehumidification technologies. After heating seawater by waste heat and evaporating the water, low-temperature air is used to condense the water vapor. The dehydrated seawater can be used for moisture absorption for the condensation of high-humidity air. The dehydrated seawater can also be used to preheat the seawater that has not been evaporated. The present invention combines the dew point evaporation desalination technology, waste heat recovery technology, solution dehumidification and indirect evaporation air-air heat exchange technology, makes full and efficient use of waste heat resources, greatly reduces the energy cost of seawater desalination, can be used in any occasion where fresh water is needed, saves energy, and has strong practicability.

Description

Technical Field

[0001] The present invention relates to the technical field of seawater desalination, and specifically to a seawater desalination unit. Background Art

[0002] Currently, there are more than 20 kinds of global seawater desalination technologies, including reverse osmosis method, low multiple-effect, multi-stage flash distillation, electrodialysis method, vapor compression distillation, dew point evaporation method, combined heat and power generation, combined heat and membrane production, and seawater desalination technologies using nuclear energy, solar energy, wind energy, tidal energy, etc., as well as a number of pretreatment and post-treatment processes such as microfiltration, ultrafiltration, and nanofiltration. Generally speaking, from a large classification, it is mainly divided into two categories: distillation method (thermal method) and membrane method. Among them, low multiple-effect distillation method, multi-stage flash distillation method, and reverse osmosis membrane method are the global mainstream technologies. Generally, the low multiple-effect has advantages such as energy saving, low requirement for seawater pretreatment, and high quality of desalinated water; the reverse osmosis membrane method has advantages such as low investment and low energy consumption, but has high requirements for seawater pretreatment; the multi-stage flash distillation method has advantages such as mature technology, reliable operation, and large device output, but has relatively high energy consumption.

[0003] Currently, as an alternative and incremental technology for fresh water resources, seawater desalination has been increasingly emphasized by many coastal countries in the world; seawater desalination requires a large amount of energy and the economic benefit is not high.

[0004] The dew point evaporation desalination technology is a new method for desalination of brackish water and seawater. It is based on the principle of humidification and dehumidification of the carrier gas, and at the same time recovers the heat of condensation and dehumidification. The heat transfer efficiency is controlled by the heat transfer on the mixed gas side. The dew point evaporation desalination technology uses air as the carrier, and makes fresh water by humidifying and dehumidifying it with seawater or brackish water, and couples the dehumidification process with the humidification process through heat transfer, so that the latent heat of condensation is directly transferred to the evaporation chamber to provide the latent heat of vaporization for evaporating the brine, in order to improve the thermal efficiency of the process. Two dew point evaporation desalination devices with effective heat transfer areas of 9.6 m² and 2.75 m² respectively for humidification / dehumidification coupling were established. The corresponding experimental device and computer data acquisition system were established. The basic process and parameter correlation experiments of dew point evaporation desalination and the enhanced heat / mass transfer desalination experiments were successfully completed respectively. Summary of the Invention

[0005] The purpose of the present invention is to provide a seawater desalination unit to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A seawater desalination unit includes a seawater spraying section, a condensation section, a dehumidification section, a preheating section, and a heat exchange section. The seawater inlet pipeline of the seawater spraying section passes through the preheating section and the heat exchange section.

[0007] Preferably, the seawater spraying section includes a spraying chamber. The inner side of the evaporation chamber communicates with one side of the condensation section. A concentrated seawater tank is provided at the bottom inside the evaporation chamber. A seawater evaporation core is provided on top of the concentrated seawater tank. A seawater spraying row communicated with the seawater inlet pipeline is provided on top of the seawater evaporation core.

[0008] Preferably, the condensation section includes a condensation chamber and an evaporation chamber. An air-air heat exchanger is provided between the condensation chamber and the evaporation chamber.

[0009] Preferably, a fresh water tank is provided at the bottom inside the condensation chamber.

[0010] Preferably, a cold water spraying row is provided at the top on one side of the condensation chamber for the air-air heat exchanger. The cold water spraying row is connected to a fresh water source.

[0011] Preferably, the dehumidification section includes a dehumidification chamber. A dilute seawater tank is provided at the bottom inside the dehumidification chamber. A dehumidification core is provided on top of the dilute seawater tank. A dehumidification spraying row is provided on top of the dehumidification core.

[0012] Preferably, one end of the spraying row is connected to a dehumidification solution pipeline and a solution spraying pipeline. The dehumidification solution pipeline is connected to the preheating section, and a solution solenoid valve is provided on the pipeline of the dehumidification solution pipeline.

[0013] Preferably, the preheating section includes a waste heat recovery heat exchanger.

[0014] Preferably, the heat exchange section includes an external heat source and a titanium tube heat exchanger. A heating circulation pipeline is provided between the external heat source and the titanium tube heat exchanger. A heating circulation pump is provided on the heating circulation pipeline.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This seawater desalination unit can make full use of waste heat resources and produce fresh water through air humidification and condensation dehumidification technologies. After heating seawater by waste heat and evaporating the water, the water vapor is condensed by low-temperature air. The dehydrated seawater can be used for moisture absorption for the condensation of high-humidity air. The dehydrated seawater can also be used for preheating the seawater that has not been evaporated. The present invention combines the dew point evaporation desalination technology, waste heat recovery technology, solution dehumidification and indirect evaporation air-air heat exchange technology, makes full and efficient use of waste heat resources, greatly reduces the energy cost of seawater desalination, can be used in any occasion where fresh water is needed, saves energy, and has strong practicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram in a preferred embodiment of the present invention.

[0017] In the figure: 1. External heat source; 2. Heating circulation pipeline; 3. Titanium tube heat exchanger; 4. Heating circulation pump; 5. Seawater inlet regulating valve; 6. Seawater inlet pipeline; 7. Seawater delivery pump; 8. First air inlet; 9. Concentrated seawater tank; 10. Seawater spray row; 11. Seawater evaporation core; 12. Cold water spray solenoid valve; 13. Cold water spray row; 14. Condensation air outlet; 15. Condensation fan; 16. Freshwater tank; 17. Evaporation air outlet; 18. Evaporation fan; 19. Air-air heat exchanger; 20. Solution spray pipeline; 21. Dehumidification spray row; 22. Dehumidification core; 23. Second air inlet; 24. Seawater discharge valve; 25. Seawater discharge pump; 26. Dilute seawater tank; 27. Dehumidification spray pump; 28. Freshwater storage tank; 29. Freshwater discharge valve; 30. Solution solenoid valve; 31. Dehumidification solution pipeline; 32. Waste heat recovery heat exchanger. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] The present invention provides a technical solution:

[0020] Please refer to Figure 1 , a seawater desalination unit, including a seawater spray section, a condensation section, a dehumidification section, a preheating section and a heat exchange section. The seawater inlet pipeline of the seawater spray section introduces seawater and passes through the preheating section and the heat exchange section during the process.

[0021] Among them, the heat exchange section includes an external heat source 1, a heating circulation pipeline 2, a titanium tube heat exchanger 3, and a heating circulation pump 4. The external heat source 1 can use solar energy equipment. The preheating section uses a waste heat recovery heat exchanger 32. Dilute seawater is transported by a seawater delivery pump 7 and enters the waste heat recovery heat exchanger 32 from the seawater inlet pipeline 6 to perform heat exchange with the high-concentration seawater transported through the dehumidification solution pipeline 31 under the action of a dehumidification spray pump 27 from the concentrated seawater tank 9. A seawater inlet regulating valve 5 is provided on the seawater inlet pipeline 6.

[0022] After the diluted seawater is preheated, it enters the titanium tube heat exchanger 3 through the seawater inlet pipeline 6, and exchanges heat with the external heat source 1 passing through the heating circulation pipeline under the action of the heating circulation pump 2 in the titanium tube heat exchanger 3. After the diluted seawater is reheated, it enters the seawater spray row 10 in the seawater spray section, is sprayed onto the seawater evaporation core 11, and performs heat and moisture exchange with the air from the first air inlet 8. The water in the seawater is evaporated into a gaseous state, forming high-temperature and humid air, and under the action of the evaporation fan 18, it enters the condensation section. After the diluted seawater evaporates, it falls into the concentrated seawater pool 9, and a dehumidification spray pump 27 is provided in the concentrated seawater pool 9.

[0023] The condensation section includes a condensation chamber and an evaporation chamber, and an air-to-air heat exchanger 19 is arranged between the condensation chamber and the evaporation chamber. The air-to-air heat exchanger 19 generally uses a plate-type total heat recovery device. As long as the temperature of the dehumidified fresh air is lower than the dew point temperature of the high-temperature and high-humidity air from the seawater spray section, the water vapor can be condensed into liquid water, flow down along the direction of the air inlet flow channel, and drip into the fresh water pool 16. The material of the plate-type total heat recovery device can be heat transfer aluminum foil, or copper foil or stainless steel foil. The air flow channel of the hot air is slightly wider, leaving a condensate channel.

[0024] The spray chamber is communicated with the condensation chamber. A condensation air outlet 14 is opened at the top of the condensation chamber, and a condensation fan 15 is arranged at the bottom of the condensation air outlet 14. The evaporation chamber is communicated with the dehumidification chamber. An evaporation air outlet 17 is arranged at the top of the evaporation chamber, and an evaporation fan 18 is arranged at the bottom of the evaporation air outlet 17.

[0025] In the condensation section, the high-temperature and humid air exchanges heat with the fresh air from the dehumidification section through the air-to-air heat exchanger 19, and the water vapor is initially condensed into water and falls into the fresh water pool 16. If the relative humidity of the outdoor air is relatively high, the solution solenoid valve 30 on the dehumidification solution pipeline 31 is closed. The concentrated seawater after evaporation is sprayed onto the dehumidification core 22 through the solution spray pipeline 20 and the dehumidification spray row 21 under the action of the dehumidification spray pump 27 to dehumidify the fresh air from the second air inlet 23 and reduce the dew point temperature of the incoming air. Then, the cold water spray solenoid valve 12 is opened, and tap water is sprayed from the cold water spray row 13 into the cooling channel of the air-to-air heat exchanger 19 to reduce the incoming air temperature to close to the wet bulb temperature of the incoming air after dehumidification, so as to further improve the condensation effect of the water vapor. The seawater after moisture absorption falls into the diluted seawater pool 26 and is discharged from this system through the seawater discharge pump 25 and the seawater discharge valve 24.

[0026] During the seawater desalination process, both the condensation fan 15 and the evaporation fan 18 need to be turned on. In the condensation section, the high-temperature and high-humid air generated after the seawater evaporates exchanges heat with the dehumidified outdoor air, and the condensed water vapor flows into the fresh water pool 16. When the water level in the fresh water pool 16 is relatively high, the fresh water discharge solenoid valve 29 is opened, and the fresh water is sent into the fresh water storage tank 28 through the fresh water discharge pipeline.

[0027] The air-to-air heat exchanger 19 generally uses a plate-type total heat recovery device. As long as the temperature of the dehumidified fresh air is lower than the dew point temperature of the high-temperature and high-humidity air from the seawater spray section, water vapor can condense into liquid water and flow down along the direction of the incoming air flow channel, dripping into the fresh water tank 16. The material of the plate-type total heat recovery device can be heat transfer aluminum foil, or copper foil or stainless steel foil. The air flow channel for the hot air is slightly wider, leaving a condensate channel.

[0028] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inner", "front", "center", "both ends", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0029] In addition, the terms "first", "second", "third", "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third", "fourth" may explicitly or implicitly include at least one of such features.

[0030] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "set", "connected", "fixed", "swivelly connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. Unless otherwise clearly limited, for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A seawater desalination unit, characterized in that: it includes a seawater spraying section, a condensation section, a dehumidification section, a preheating section and a heat exchange section, and the seawater inlet pipeline of the seawater spraying section passes through the preheating section and the heat exchange section; the seawater spraying section includes a spraying chamber, the inner side of the spraying chamber is communicated with one side of the condensation section, a concentrated seawater tank (9) is arranged at the bottom of the inner side of the spraying chamber, a seawater evaporation core (11) is arranged at the top of the concentrated seawater tank (9), and a seawater spraying row (10) communicated with the seawater inlet pipeline (6) is arranged at the top of the seawater evaporation core (11); the dehumidification section includes a dehumidification chamber, a dilute seawater tank (26) is arranged at the bottom of the inner side of the dehumidification chamber, a dehumidification core (22) is arranged at the top of the dilute seawater tank (26), and a dehumidification spraying row (21) is arranged at the top of the dehumidification core (22); a dehumidification spraying pump (27) is arranged in the concentrated seawater tank (9); the evaporated concentrated seawater is sprayed onto the dehumidification core (22) through a solution spraying pipeline (20) and a dehumidification spraying row (21) under the action of the dehumidification spraying pump (27) to dehumidify the fresh air from the second air inlet (23) and reduce the dew point temperature of the incoming air.

2. A seawater desalination unit according to claim 1, characterized in that: the condensation section includes a condensation chamber and an evaporation chamber, and an air-to-air heat exchanger (19) is arranged between the condensation chamber and the evaporation chamber.

3. A seawater desalination unit according to claim 2, characterized in that: a fresh water tank (16) is arranged at the bottom of the inner side of the condensation chamber.

4. A seawater desalination unit according to claim 2, characterized in that: a cold water spraying row (13) is arranged at the top of one side of the condensation chamber of the air-to-air heat exchanger (19), and the cold water spraying row (13) is connected to a fresh water source.

5. A seawater desalination unit according to claim 1, characterized in that: one end of the spraying row (21) is connected with a dehumidification solution pipeline (31) and a solution spraying pipeline (20), the dehumidification solution pipeline (31) is connected to the preheating section, and a solution solenoid valve (30) is arranged on the pipeline of the dehumidification solution pipeline (31).

6. A seawater desalination unit according to claim 1, characterized in that: the preheating section includes a waste heat recovery heat exchanger (32).

7. A seawater desalination unit according to claim 1, characterized in that: the heat exchange section includes an external heat source (1) and a titanium tube heat exchanger (3), a heating circulation pipeline (2) is arranged between the external heat source (1) and the titanium tube heat exchanger (3), and a heating circulation pump (4) is arranged on the heating circulation pipeline (2).

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