Solar energy heat-collecting pressure-reducing evaporation seawater desalination device

Abstract

A solar-powered, high-pressure-reducing, evaporative seawater desalination device includes a solar thermal panel assembly, an array of seawater evaporators, a freshwater condenser, a steam ejector, a seawater storage tank and a brine storage tank, an assembly of brine and freshwater temporary storage tanks, heat transfer oil, and a freshwater transfer pump. The solar thermal panel assembly transfers solar radiation heat energy to the heat transfer oil, which, through heat exchanger coils, exchanges heat energy with seawater outside the coils to form steam. The steam then drives a Venturi-type steam ejector in the next stage to evacuate the connected seawater evaporators, reducing the internal pressure. Utilizing the residual heat from the heat transfer oil introduced in the first seawater evaporator, the seawater evaporates under the reduced pressure in the evaporator. The steam is then condensed and recovered as freshwater by the subsequent freshwater condenser.

Description

Technical Field

[0001] This invention relates to the technical field of a seawater desalination device, and in particular to a seawater desalination device that combines solar thermal energy collection with depressurized evaporation. The device uses solar radiation to collect heat and then combines it with a steam ejector for depressurized evaporation, evaporating seawater and then condensing it into fresh water. Background Technology

[0002] Current seawater desalination equipment can be divided into two main categories based on its core technology: using RO reverse osmosis membranes to filter seawater to remove salt and produce fresh water, or using distillation or evaporation to evaporate and then condense seawater.

[0003] Since the core technology of the RO reverse osmosis membrane cannot be compared with that of the device of this invention, it will not be discussed here. Instead, we will briefly describe the existing seawater desalination technologies that use evaporation or distillation:

[0004] 1. Using solar energy as a heat source, water in a heat pipe is sent to a seawater evaporator to evaporate the seawater. The steam is then condensed into freshwater through a heat exchanger. This method is the most direct, operating in a 1:1 ratio. The heat source turns the water flow inside the heat pipe into high-temperature water, which is then evaporated in the evaporator and condensed into freshwater. The advantage of this method is its simplicity in terms of technology and equipment, but the disadvantage is its low thermal efficiency. Therefore, although this technology has seen small-scale applications, no commercially operational modules have been found on the market to date.

[0005] 2. Using heat transfer oil as the medium, the oil flows through pipelines. A heat absorption plate is placed at the focusing hotspot of a solar panel, allowing the oil to pass through. The oil is then heated to 300-600°C by solar heat concentration. It then flows through a heat exchanger to contact seawater, causing the seawater to evaporate and condense into fresh water. This method differs from the previous one in that it uses heat transfer oil as the medium, exchanging heat with seawater through a heat exchanger to evaporate the seawater, which is then condensed. The advantage of this method is that it allows the heat transfer oil to reach a high temperature, rapidly evaporating seawater into high-pressure steam, which is then condensed. However, the disadvantage is that the efficiency of the high-temperature steam condensation process is not ideal; therefore, no commercially operational units have been seen on the market to date.

[0006] 3. Water is heated and evaporated into steam using steam energy or electricity. The steam is then indirectly heated by the heat exchanger coils in the seawater evaporator. Simultaneously, seawater is fed into the evaporation tank for staged heating and evaporation. The resulting steam is then condensed to obtain fresh water. This process is also known as MSF (Multi-stage Flash) evaporation. Its advantage is that it uses high-temperature, high-pressure steam as the medium, exchanging heat with seawater through a heat exchanger. This allows the seawater to undergo multi-stage evaporation in the evaporation tank before condensation. The advantage of this process is that it allows for large-scale equipment production and the production of large quantities of fresh water. However, its disadvantages include the need for large-scale heating systems to achieve economic efficiency due to the use of high-pressure, high-temperature steam, or the need for integration with power plants or petrochemical plants, resulting in relatively high setup costs.

[0007] 4. Steam is used to extract air from the seawater evaporator through a steam ejector, while simultaneously feeding seawater into the evaporator for distillation. This process is designed as a multi-stage distillation unit, and because of the steam extraction and pressure reduction operation, it is called MED-TVC (Multiple Effect Distillation with Thermal Vapor Compression). Similar to the aforementioned multi-effect flash evaporation method, this process requires both steam and electricity, and therefore is often integrated with power plants or petrochemical plants, requiring a certain scale, thus resulting in relatively high installation costs.

[0008] In summary, the energy consumption of existing seawater desalination technologies and processes on the market is indeed a problem and there is a real need for improvement. Summary of the Invention

[0009] To address the shortcomings of the prior art, the main objective of this invention is to provide a solar thermal depressurization seawater desalination device that utilizes the principle of depressurized evaporation, thereby improving the efficiency of seawater desalination operations, reducing energy consumption, and lowering unit operating costs.

[0010] Some embodiments of the present invention include a seawater desalination device technology, which is a seawater desalination device that uses solar energy to concentrate heat and reduce pressure to evaporate seawater, and then condenses and recovers the seawater. It uses solar energy to concentrate heat and, in conjunction with a Venturi-type steam ejector, reduces pressure to evaporate seawater. The seawater is then condensed into fresh water, which is particularly useful for water-scarce but sunny coastal areas. The device is flexible in scale and can also be applied to rivers and canals to evaporate and recover the water from rivers and canals for reuse. This can improve river pollution and increase the reuse of water resources.

[0011] Some embodiments of the present invention apply the principle of reduced pressure evaporation, which can reduce the evaporation point of seawater from 100°C to 70°C and 50°C in stages. Therefore, the residual heat of the heat transfer oil used in the previous stage can be used to make the seawater evaporate again at medium-high or medium temperature to increase the total amount of seawater evaporation.

[0012] To achieve the above objectives, the present invention provides a solar-powered thermal depressurization evaporation seawater desalination device comprising a solar thermal panel assembly, a first seawater evaporator, a second seawater evaporator, a first Venturi-type steam ejector, a first freshwater condenser, a third seawater evaporator, a second Venturi-type steam ejector, a third Venturi-type steam ejector (the second and third Venturi-type steam ejectors are combined Venturi-type steam ejectors), several seawater storage tanks, several brine storage tanks, several freshwater storage tanks, a brine temporary storage tank, a freshwater temporary storage tank, a water hammer pump, a seawater transfer pump, a freshwater transfer pump, and a brine transfer pump, etc., wherein:

[0013] The solar thermal panel assembly is equipped with a heat transfer oil pipe filled with heat transfer oil. The solar thermal panel assembly reflects sunlight to the heat transfer oil pipe, which concentrates the heat and raises the temperature of the heat transfer oil to a high temperature. The heat transfer oil is then delivered to the first-stage seawater evaporator, the second-stage seawater evaporator, and the third-stage seawater evaporator through the heat transfer oil delivery pipe to provide the heat exchange capacity of the three-stage seawater evaporators to evaporate the seawater.

[0014] The first Venturi-type steam ejector is connected to the second-stage seawater evaporator, and the combination of the second and third steam ejectors (i.e., the combination of the second and third Venturi-type steam ejectors) is connected to the third-stage seawater evaporator. The second-stage seawater evaporator utilizes the suction effect of the first Venturi-type steam ejector to reduce its internal pressure, while the combination of the second and third steam ejectors suctions air from the third-stage seawater evaporator to further reduce its internal pressure. This allows the heat transfer oil, which has already cooled down after the first stage of seawater evaporation in the first evaporator, to continue functioning in the second stage of seawater evaporation to evaporate the medium-to-high temperature seawater sprayed into the second evaporator, and to evaporate the seawater sprayed into the third-stage evaporator.

[0015] As can be seen from the above, this device utilizes the steam generated by the first-stage seawater evaporator to create a suction effect by passing the steam through the first Venturi-type steam ejector. This suction effect, caused by the steam passing through the first Venturi-type steam ejector, draws air from the second-stage seawater evaporator, reducing the internal pressure of the second-stage seawater evaporator so that the seawater can evaporate at a medium-high temperature, thereby improving operational efficiency. Similarly, when the steam passes through the combination of the second and third steam ejectors, it also continuously draws air from the third-stage seawater evaporator to reduce its pressure, allowing the seawater to evaporate at a medium temperature, thereby improving the utilization efficiency of the thermal energy converted from solar energy.

[0016] The first, second, and third seawater storage tanks directly introduce seawater. The first seawater storage tank is connected to a first water hammer pump to transport seawater into the first seawater evaporator. The second seawater storage tank is connected to a second water hammer pump to transport seawater into the second seawater evaporator. The third seawater storage tank is connected to a third water hammer pump to send seawater into the first freshwater condenser. This achieves the function of evaporating seawater or condensing freshwater without using external power to lift seawater, thereby reducing energy consumption during operation.

[0017] In a preferred embodiment, a set of steam distributors (or steam regulators) is connected above the first seawater evaporator. The steam distributors are connected to multiple steam lines to transport the steam generated from the first seawater evaporator to the steam ejector in front through three steam lines via a pressure difference. One of the steam lines introduces the steam into a first Venturi-type steam ejector, which is also connected to a second seawater evaporator. Another steam line introduces the steam into a third Venturi-type steam ejector, which is also connected to a second freshwater condenser. The negative pressure inlet of the third Venturi-type steam ejector is connected to the steam ejector outlet of the second Venturi-type steam ejector. The second Venturi-type steam ejector is connected to a third seawater evaporator, and the third Venturi-type steam ejector is connected to a second freshwater condenser.

[0018] The device further includes a fourth seawater storage tank that directly introduces seawater, and the fourth seawater storage tank uses a fourth water hammer pump to transport the seawater into the third seawater evaporator.

[0019] After the steam generated by the first seawater evaporator leaves the steam distributor, some of the steam can enter the first Venturi steam ejector through one of the steam pipelines. The first Venturi ejector then injects the steam into a first freshwater condenser after operation. At the same time, some steam is introduced into the second and third Venturi steam ejectors connected in series through another steam pipeline. Since the negative pressure inlet of the third Venturi steam ejector is connected to the steam ejection outlet of the second Venturi steam ejector, the steam outlet of the second Venturi steam ejector pressurizes the third steam ejector, increasing the Venturi negative pressure of the second steam ejector. This enhances the steam ejection effect of the second and third Venturi steam ejectors connected in series, resulting in a higher negative pressure inside the third seawater evaporator connected to the second Venturi steam ejector. Therefore, seawater evaporation can occur at a lower temperature.

[0020] The continuously flowing heat transfer oil is fed into the heat exchanger coil inside the third seawater evaporator and transported forward. Although some of the heat energy was taken away by the seawater evaporated in the second seawater evaporator when the heat transfer oil flowed through the heat exchanger coil inside the second seawater evaporator, the lower air pressure inside the third seawater evaporator allows the seawater sprayed downwards by the seawater spray nozzles in the third seawater evaporator to evaporate at a low to medium temperature. Therefore, the evaporated seawater turns into steam again and is drawn up by the second Venturi steam ejector and sucked into the third Venturi steam ejector, and then sprayed into the second freshwater condenser in the next stage for condensation and recovery as freshwater.

[0021] In a preferred embodiment of the present invention, the solar-powered thermal depressurization evaporation seawater desalination device includes a solar thermal panel assembly, a first seawater evaporator, a second seawater evaporator, a first freshwater condenser, a first Venturi-type steam ejector, a first seawater storage tank, a second seawater storage tank, and a third seawater storage tank, wherein:

[0022] The solar thermal panel assembly receives the heat transfer oil and raises the temperature of the heat transfer oil to a high temperature through the heat collection effect of the solar thermal panel assembly. The heat transfer oil is then transported to the first seawater evaporator and the second seawater evaporator through the heat transfer oil delivery pipe to provide the first seawater evaporator and the second seawater evaporator with heat energy to evaporate the seawater.

[0023] The first Venturi-type steam ejector is connected to the first seawater evaporator, the second seawater evaporator, and the first freshwater condenser via a steam distributor (steam regulator). The steam generated by the first seawater evaporator drives the first Venturi-type steam ejector to evacuate the second seawater evaporator, thereby reducing the internal pressure of the second seawater evaporator. This allows the heat transfer oil, which has already been cooled after the first stage of seawater evaporation in the first seawater evaporator, to play a role in the seawater evaporation process of the second seawater evaporator, enabling the evaporation of medium-high temperature seawater within the second seawater evaporator.

[0024] The first seawater storage tank, the second seawater storage tank, and the third seawater storage tank directly introduce seawater. The first seawater storage tank is connected to a first water hammer pump to transport seawater into the first seawater evaporator. The second seawater storage tank is connected to a second water hammer pump to transport seawater into the second seawater evaporator. The third seawater storage tank is connected to a third water hammer pump to send seawater into the first freshwater condenser.

[0025] The apparatus of the above embodiment further includes a steam distributor connected above the first seawater evaporator. The steam distributor is connected to several steam pipelines for conveying the steam generated by the first seawater evaporator to the steam pipelines through the steam distributor by pressure difference. One of the steam pipelines introduces the steam into a second Venturi-type steam ejector. The second Venturi-type steam ejector is also connected to a third seawater evaporator. Another steam pipeline introduces the steam into a third Venturi-type steam ejector. The third Venturi-type steam ejector is also connected to a second freshwater condenser, and the negative pressure inlet of the third Venturi-type steam ejector is connected to the steam outlet of the second Venturi-type steam ejector.

[0026] The device further includes a fourth seawater storage tank that directly introduces seawater, and the fourth seawater storage tank uses a fourth water hammer pump to transport the seawater into the third seawater evaporator.

[0027] After the steam generated by the first seawater evaporator leaves the steam distributor, some of the steam can be introduced into the second and third Venturi steam ejectors connected in series through one of the steam pipelines and another of the steam pipelines. Since the negative pressure inlet of the third Venturi steam ejector is connected to the steam jet outlet of the second Venturi steam ejector, the nozzle pressurization effect generated by the steam jet outlet of the second Venturi steam ejector and the depressurization effect of the negative pressure inlet of the nozzle of the third Venturi steam ejector improve the steam jet extraction efficiency of the second and third Venturi steam ejectors connected in series. This results in a higher pressure drop inside the third seawater evaporator connected to the second Venturi steam ejector, thereby allowing the seawater to evaporate at a lower temperature.

[0028] The continuously flowing heat transfer oil is fed into the heat exchanger coil inside the third seawater evaporator and transported forward. When the aforementioned heat transfer oil flows through the heat exchanger coil inside the second seawater evaporator, some of the heat energy has been taken away by the seawater evaporated in the second seawater evaporator. However, since the air pressure inside the third seawater evaporator is lower than that inside the second seawater evaporator, the seawater sprayed downwards by the seawater sprayer in the third seawater evaporator can evaporate at a lower temperature. The evaporated seawater turns into steam again and is drawn into the second and third Venturi steam ejectors, and sprayed into the second freshwater condenser in the next stage for condensation and recovery as freshwater.

[0029] In a preferred embodiment, a brine storage tank is connected below the third seawater evaporator. The brine storage tank is connected to a brine transfer pump, which is connected to a brine tank. The brine storage tank is used to receive the brine falling from the third seawater evaporator. When the brine level in the brine storage tank reaches a high level, it is then transported by the brine transfer pump to the brine tank for centralized treatment and reuse.

[0030] In a preferred embodiment, the present invention further includes a fifth seawater storage tank for directly introducing seawater, wherein the fifth seawater storage tank uses a fifth water hammer pump to transport seawater into the third seawater evaporator.

[0031] The steam generated by the third seawater evaporator is sent to the second freshwater condenser through a steam pipeline. The steam is sprayed onto the surface of the heat exchanger coil inside the second freshwater condenser by a steam sprayer installed inside the condenser. A fifth water hammer pump located around the second freshwater condenser continuously delivers low-temperature seawater through the heat exchanger coil. Through heat transfer, the steam in contact with the heat exchanger coil turns into freshwater and falls into a freshwater storage tank located below the condenser. When the water level in the storage tank reaches a high level, the freshwater is then pumped into a freshwater tank for external distribution by a freshwater transfer pump.

[0032] In a preferred embodiment, the solar thermal panel assembly uses a batch of parabolic solar thermal panel assemblies. Each solar thermal panel assembly has a heat transfer oil circulation pipeline configured on the focusing line above it. The heat transfer oil circulation pipeline is filled with heat transfer oil and is pumped by a heat transfer oil pump to circulate. The solar thermal panel assembly is used to focus and reflect the heat energy of the solar energy onto the heat transfer oil circulation pipeline, so that the heat transfer oil inside the heat transfer oil circulation pipeline continuously rises to the temperature required for operation.

[0033] In a preferred embodiment, the first seawater evaporator is equipped with a heat exchanger coil, so that when the heat transfer oil flows through the first seawater evaporator, the surface of the heat exchanger coil inside the first seawater evaporator can generate high temperature.

[0034] Because the first seawater storage tank is below the sea surface, seawater can be introduced from the sea surface through the elevation difference. Then, using the physical effect of the elevation difference, the seawater is sent into the first seawater evaporator by the first water hammer pump. The first seawater evaporator has a seawater sprayer with several spray holes. The seawater sprayer can spray the seawater through these spray holes onto the high-temperature heat exchanger coils on the inner surface of the first seawater evaporator, causing the seawater to evaporate into steam instantly. A small amount of unevaporated seawater becomes brine due to the increased salinity and flows into the brine tank below.

[0035] In a preferred embodiment, a brine storage tank is connected below the first seawater evaporator. The brine storage tank is connected to a brine transfer pump, which is connected to a brine tank. The brine storage tank is used to receive the brine falling from the first seawater evaporator. When the brine level in the brine storage tank reaches a high level, it is then transported by the brine transfer pump to the brine tank for centralized treatment and reuse.

[0036] In a preferred embodiment, a steam distributor is connected above the first seawater evaporator. The steam distributor is connected to multiple steam lines to transport the steam generated by the first seawater evaporator to one of the steam lines through the steam distributor via a pressure difference. The steam line then guides the steam into the first Venturi-type steam ejector. As the steam passes through the first Venturi-type steam ejector, it creates a suction effect on the second seawater evaporator connected below it, causing a pressure drop inside the second seawater evaporator, resulting in a negative pressure state. At this time, the steam output from the steam distributor enters the interconnected second and third Venturi-type steam ejectors. Since the outlet of the second Venturi-type steam ejector is connected to the inlet of the third Venturi-type steam ejector, the enhanced suction effect of the third Venturi-type steam ejector further reduces the internal pressure of the third seawater evaporator connected to the second and third Venturi-type steam ejectors, thereby enabling the seawater at a medium temperature to evaporate.

[0037] The continuously flowing heat transfer oil is introduced into the heat exchanger coil inside the second seawater evaporator and continuously transported forward. Although some of the heat energy has been taken away by the seawater evaporated by the first seawater evaporator when the heat transfer oil flows through the heat exchanger coil inside the first seawater evaporator, the air pressure inside the second seawater evaporator is now in a negative pressure state. This allows the seawater sprayed downwards by the seawater sprayer in the second seawater evaporator to evaporate at a lower temperature. The evaporated seawater is then evaporated into steam at this lower temperature and sucked into the first Venturi-type steam ejector and sprayed into the first freshwater condenser in the next stage for condensation and recovery as freshwater.

[0038] In a preferred embodiment, a brine storage tank is connected below the second seawater evaporator. The brine storage tank is connected to a brine transfer pump, which is connected to a brine tank. The brine storage tank is used to receive the brine falling from the second seawater evaporator. When the brine level in the brine storage tank reaches a high level, it is then transported by the brine transfer pump to the brine tank for centralized treatment and reuse.

[0039] In a preferred embodiment, the steam generated by the second seawater evaporator is sent into the first freshwater condenser through a steam pipeline. The steam is sprayed onto the surface of the heat exchanger coil inside the first freshwater condenser by a steam sprayer installed inside the first freshwater condenser. This causes the third water hammer pump, which is located around the first freshwater condenser, to continuously deliver room-temperature seawater through the heat exchanger coil inside the first freshwater condenser. Through the heat transfer effect, the steam in contact with the surface of the heat exchanger coil of the first freshwater condenser turns into freshwater and falls into a freshwater storage tank located below the first freshwater condenser. When the water level in the freshwater storage tank reaches a high level, the freshwater is then sent to a freshwater tank by a freshwater delivery pump for external distribution.

[0040] In summary, although the present invention, namely the solar-powered thermal depressurization evaporation seawater desalination device, achieves seawater desalination by evaporating and then condensing seawater using solar thermal energy, it differs from other distillation or evaporation-based seawater desalination technologies in that it does not directly condense the steam generated by the first seawater evaporator in the first stage. Instead, it first converts this high-temperature steam into steam energy, and then uses a Venturi-type steam ejector to pump air from the connected second and third seawater evaporators, reducing the internal pressure of the second and third seawater evaporators to, for example, 30,000 Pa and 10,000 Pa, respectively. This reduces the seawater evaporation temperature to, for example, 70°C and 50°C, respectively. This allows the solar-powered thermal depressurization evaporation seawater desalination device to produce a three-stage seawater evaporation effect. However, its heat source is only a set of solar thermal panels connected in series and a heat transfer oil pipeline. The final result is that all the evaporated steam is condensed in the first and second freshwater condensers without any leakage.

[0041] In other words, compared with the traditional solar-thermal depressurization seawater desalination system, the solar-thermal depressurization seawater desalination device of the present invention uses one times the heat energy to sequentially carry out, for example, three seawater evaporation processes through the principle of depressurization evaporation. Although the total amount of freshwater obtained cannot be determined to be more than three times the amount of freshwater, the heat energy obtained from one heat collection can complete three seawater evaporation processes. Its high-efficiency energy conversion is certain, which is significantly different from existing technologies on the market. This is certain. Attached Figure Description

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0043] Figure 1 This invention provides a schematic diagram of the overall device and process flow of a solar-powered, thermally concentrated, depressurized, evaporative seawater desalination device.

[0044] Figure 2 : A high-temperature atmospheric pressure seawater evaporation device configured at the front end of the solar thermal depressurization evaporation seawater desalination device of the present invention, and a process diagram;

[0045] Figure 3 : A schematic diagram of the medium-high temperature seawater depressurization evaporation device configured in the solar thermal depressurization evaporation seawater desalination device of the present invention;

[0046] Figure 4 : A schematic diagram of the first set of seawater condensation steam recovery freshwater devices configured in the solar thermal depressurization evaporation seawater desalination device of the present invention;

[0047] Figure 5 : A schematic diagram of the medium-temperature low-pressure seawater evaporation device configured in the solar thermal depressurization evaporation seawater desalination device of the present invention;

[0048] Figure 6 : A schematic diagram of the second stage seawater condensation steam recovery freshwater device configured in the solar thermal depressurization evaporation seawater desalination device of the present invention;

[0049] Figure 7 : A schematic diagram of the process block of the solar thermal depressurization evaporation seawater desalination device of the present invention;

[0050] Explanation of reference numerals in the attached figures

[0051] 10 First Seawater Evaporator

[0052] 11 First Seawater Storage Tank

[0053] 12 First Water Hammer Pump

[0054] 13 Brine Temporary Storage Tank

[0055] 131 brine transfer pump

[0056] 14 Steam distributor

[0057] 15 Heat Transfer Oil Temporary Storage Tank

[0058] 20 Second Seawater Evaporator

[0059] 21 Second Seawater Storage Tank

[0060] 22 Second Water Hammer Pump

[0061] 23 Brine Temporary Storage Tank

[0062] 231 brine transfer pump

[0063] 24 First Venturi Steam Ejector

[0064] 25 Heat Transfer Oil Temporary Storage Tank

[0065] 30 Third Seawater Evaporator

[0066] 31 Fourth Seawater Storage Tank

[0067] 32 Fourth Water Hammer Pump

[0068] 33 Brine Temporary Storage Tank

[0069] 331 brine transfer pump

[0070] 34 Second Venturi Steam Ejector

[0071] 35 Third Venturi Steam Ejector

[0072] 36 Heat Transfer Oil Temporary Storage Tank

[0073] 37 Thermal oil transfer pump

[0074] 40 First Freshwater Condenser

[0075] 41 Third Seawater Storage Tank

[0076] 42 Third Water Hammer Pump

[0077] 43 Seawater Buffer Tank

[0078] 44 Seawater Temporary Storage Tank

[0079] 441 Seawater Transfer Pump

[0080] 45 Freshwater Temporary Storage Tank

[0081] 451 Freshwater Transfer Pump

[0082] 50 Second Freshwater Condenser

[0083] 51 Fifth Seawater Storage Tank

[0084] 52 Fifth Water Hammer Pump

[0085] 53 Seawater Buffer Tank

[0086] 54 Seawater Temporary Storage Tank

[0087] 541 Seawater Transfer Pump

[0088] 55 Freshwater Temporary Storage Tank

[0089] 551 Freshwater Transfer Pump

[0090] 60 solar thermal panel combination

[0091] 61 Thermal oil expansion tank

[0092] 62 heat transfer oil transfer pump

[0093] 70 brine tank

[0094] 71 brine transfer pump

[0095] 80 freshwater tanks

[0096] 81 Freshwater transfer pump. Detailed Implementation

[0097] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0098] Please see Figure 1 As shown, the solar-powered thermal decompression evaporation seawater desalination device of the present invention uses a thermal conversion method to convert solar energy into thermal energy, which evaporates seawater and then condenses and recovers it to obtain fresh water. The device also includes two major operating systems: seawater evaporation and freshwater condensation.

[0099] The seawater evaporation system also includes: (1) a high-temperature, normal-pressure seawater evaporation system; (2) a medium-temperature, low-pressure seawater evaporation system; or / and (3) a medium-temperature, low-pressure seawater evaporation system.

[0100] This freshwater condensation system uses steam generated at high temperature and normal pressure as steam energy to drive a first Venturi-type steam ejector 24, a second Venturi-type steam ejector 34, and a third Venturi-type steam ejector 35 to extract air from the evaporation chambers of the second seawater evaporator 20 (at medium-high temperature and low pressure) and the third seawater evaporator 30 (at medium temperature and low pressure). This reduces the internal pressure of the evaporation chambers, allowing seawater to evaporate at medium-high temperature (e.g., 70°C) and medium temperature (e.g., 50°C), respectively, thereby achieving the goal of improving seawater evaporation efficiency.

[0101] The steam evaporated in the first seawater evaporator 10, a portion of which, before being condensed and recovered, first passes through the nozzle of the first Venturi steam ejector 24 and then enters the first freshwater condenser 40 for condensation. This process involves using this portion of steam to pump air from the seawater evaporator 20, creating a pressure drop in the evaporation chamber. The remaining steam passes through the nozzles of the second Venturi steam ejector 34 and the third Venturi steam ejector 35 and enters the second freshwater condenser 50 for condensation and recovery. Similarly, the steam passes through these two steam ejectors (i.e., the second Venturi steam ejector 34 and the third Venturi steam ejector 35). The steam will have a suction effect on the seawater evaporator 30. Since the Venturi nozzles of the second Venturi steam ejector 34 and the third Venturi steam ejector 35 are connected in series, their suction energy is stronger, which can cause the seawater evaporator 30 to produce a large pressure drop effect, allowing the seawater to evaporate at a medium temperature. Finally, the steam evaporated by the first seawater evaporator 10 also enters the first freshwater condenser 40 through the first Venturi steam ejector 24 and is condensed and recovered. The steam generated by the third seawater evaporator 30 enters the second freshwater condenser 50 through the second Venturi steam ejector 34 and the third Venturi steam ejector 35 and is condensed and recovered.

[0102] In summary, the steam generated by the first seawater evaporator 10 is not immediately condensed and recovered. Instead, it is used as steam kinetic energy to drive the first Venturi steam ejector 24, the second Venturi steam ejector 34, and the third Venturi steam ejector 35. Ultimately, the steam is introduced into the first freshwater condenser 40 or the second freshwater condenser 50 through the nozzles of the steam ejectors and recovered, thus avoiding any waste of resources.

[0103] The implementation of the solar thermal depressurization evaporation seawater desalination device of the present invention is described in detail below, including the apparatus and process of two systems: seawater evaporation and freshwater condensation.

[0104] 1. The seawater evaporation system and process include:

[0105] Seawater evaporation processes, depending on their different physical characteristics during operation, include:

[0106] (1) High-temperature atmospheric pressure seawater evaporation process, (2) Medium-high temperature reduced pressure seawater evaporation process, or / and (3) Medium-temperature low pressure seawater evaporation process, etc., are described below:

[0107] 1.1 The high-temperature, atmospheric-pressure seawater evaporation process includes (see [link to relevant documentation]). Figure 2 (as shown)

[0108] This process is a pilot process for the solar thermal depressurization evaporation seawater desalination device of the present invention. The device includes: a thermal oil expansion tank 61, a solar thermal plate assembly 60 and a control device (not shown in the figure), a thermal oil transfer pump 62, a first seawater evaporator 10, a first seawater storage tank 11, a first water hammer transfer pump 12, a brine temporary storage tank 13, a steam distributor 14, and a thermal oil temporary storage tank 15, etc.

[0109] During operation, heat transfer oil is first placed in the heat transfer oil expansion tank 61, and the heat transfer oil transfer pump 62 is started to transport the heat transfer oil to the forward heat transfer oil transfer pipe. Then, it is transported back to the heat transfer oil expansion tank 61 through the heat transfer oil transfer pump 37 configured in the third seawater evaporator 30. The heat transfer oil expansion tank 61 is positioned at a higher level than all the seawater evaporators, so the entire heat transfer oil transfer pipe is filled with heat transfer oil during operation.

[0110] In this embodiment, the solar thermal panel assembly 60 is a parabolic solar thermal panel assembly, and the solar thermal panel assembly 60 is equipped with a heat transfer oil circulation pipeline. The heat transfer oil circulation pipeline is used to supply heat transfer oil flow, and the solar thermal panel assembly 60 is used to focus the solar thermal energy and project it onto the heat transfer oil circulation pipeline, so that the heat transfer oil inside the heat transfer oil circulation pipeline rises to a high temperature of 170°C.

[0111] When the heat transfer oil passes through the solar thermal concentrator assembly 60, the solar thermal concentrator assembly 60 reflects sunlight, and its focal point is directed at the heat transfer oil pipe above. Therefore, the heat transfer oil in the heat transfer oil pipe will continuously heat up to, for example, 170°C. Through the continuous circulation of the heat transfer oil, the heat of the heat transfer oil is carried into the heat exchanger coils of the first seawater evaporator 10, the second seawater evaporator 20, and the third seawater evaporator 30, and the seawater splashed into and touching the surface of the heat exchanger coils evaporates instantly.

[0112] As for the seawater used as feed, the seawater is drawn from the sea surface into the first seawater storage tank 11 by means of the elevation difference. Then, by using the elevation difference, the first water hammer pump 12 transports the seawater through an independent brine discharge pipe to the seawater spray nozzle installed in the first seawater evaporator 10. The seawater comes into contact with the surface of the heat exchanger coil with heat transfer oil, generating a thermal evaporation effect. The seawater that does not evaporate completely forms brine with increased salt concentration due to the increased concentration. It falls down into the brine temporary storage tank 13 through the discharge pipe. Since the pipeline that continues to rise into the first seawater evaporator 10 comes into contact with the brine discharge pipe, the rising seawater also absorbs the heat energy of the flowing brine.

[0113] The steam generated by the first seawater evaporator 10 enters the steam distributor 14 along the direction of lower pressure, and then moves forward along the direction of lower pressure. At this time, since the steam can form a suction effect by passing through the first Venturi steam ejector 24, the second Venturi steam ejector 34, and the third Venturi steam ejector 35 arranged in the second seawater evaporator 20 and the third seawater evaporator 30, the steam will continue to move forward and enter the first Venturi steam ejector 24, the second Venturi steam ejector 34, and the third Venturi steam ejector 35. The brine that fails to evaporate in the first seawater evaporator 10 falls into the brine temporary storage tank 13 below. When the brine temporary storage tank 13 reaches a high level, the control system automatically starts the brine transfer pump 131 to send the brine into the brine tank 70 for processing. After the brine in the brine tank 70 accumulates to a certain extent, it can eventually be sent to the brine treatment plant for further processing.

[0114] As can be seen from the above description, the function of the first seawater evaporator 10 is to generate high-temperature, medium-pressure steam that can be used as kinetic energy for subsequent processes, rather than directly condensing and recovering it.

[0115] 1.2 The medium- and high-temperature vacuum evaporation seawater evaporation system and process include (see [reference]). Figure 3 (as shown)

[0116] The medium-high temperature reduced pressure evaporation seawater evaporation process includes the following equipment: a second seawater evaporator 20, a first Venturi-type steam ejector 24, a second seawater storage tank 21, a second water hammer transfer pump 22, a brine temporary storage tank 23, a brine transfer pump 231, and a heat transfer oil temporary storage tank 25, etc.

[0117] During operation, except that the working conditions are reduced to 70°C due to the suction effect of the first Venturi steam ejector 24, the operation of the equipment and the flow of the fluid are the same as the operating principle of the first seawater evaporator 10.

[0118] It is worth mentioning that, because the steam from the first seawater evaporator 10 has a relatively high temperature and operating pressure of approximately 7 bar, it generates a high-speed suction effect when passing through the first Venturi-type steam ejector 24, resulting in a relatively low atmospheric pressure of approximately 30,000 Pa inside the second seawater evaporator 20. This allows the seawater to evaporate at a relatively low temperature, i.e., 70°C. This relatively low-temperature steam is drawn in by the airflow passing through the first Venturi-type steam ejector 24 and mixed with the relatively high-temperature steam from the first seawater evaporator 10, before being injected into a first freshwater condenser 40 for condensation and recovery.

[0119] 1.3 The medium-temperature low-pressure seawater evaporation system and process include (see [reference]). Figure 5 (as shown)

[0120] The seawater evaporation process in this stage is a continuation of the aforementioned medium-high temperature vacuum seawater distillation process. The equipment configured includes: a third seawater evaporator 30, a second Venturi-type steam ejector 34 and a third Venturi-type steam ejector 35 connected in series, a fourth seawater storage tank 31, a fourth water hammer pump 32, a brine temporary storage tank 33, a brine transfer pump 331, and a heat transfer oil temporary storage tank 36, etc.

[0121] During operation, except that the seawater evaporation temperature is relatively reduced to 50°C due to the suction effect of the second Venturi steam ejector 34 and the third Venturi steam ejector 35 connected in series, the operation of the equipment and the flow of the fluid are the same as the operating principle of the first seawater evaporator 10 or the second seawater evaporator 20.

[0122] It is worth mentioning that, due to the high temperature and operating pressure of the steam from the first seawater evaporator 10, a high-speed suction effect is generated when it passes through the series-connected second and third Venturi steam ejectors 34 and 35, resulting in a relatively low gas pressure of approximately 10,000 Pa inside the seawater evaporator, which allows the seawater to evaporate at a medium-low temperature of 50°C. This relatively low-temperature steam is drawn in by the airflow through the series-connected second and third Venturi steam ejectors 34 and 35 and mixed with the relatively high-temperature steam from the first seawater evaporator 10, before being injected into the second freshwater condenser 50 for condensation and recovery.

[0123] 2. Freshwater condensation system and process include:

[0124] The freshwater condensation process is used to condense and recover steam generated by seawater evaporators. The freshwater condensation unit consists of two sets: a first freshwater condenser 40, which recovers a portion of the steam generated by the first seawater evaporator 10 and all the steam generated by the second seawater evaporator 20; and a second freshwater condenser 50, which recovers a portion of the steam generated by the first seawater evaporator 10 and all the steam generated by the third seawater evaporator 30. The equipment configuration and operating procedures of these two sets of freshwater condensers are described below:

[0125] 2.1 The first group of freshwater condensation systems and processes include (please refer to...) Figure 4 (as shown)

[0126] The first freshwater condensation process includes the following equipment: a first freshwater condenser 40, a third seawater storage tank 41, a third water hammer pump 42, a seawater buffer tank 43, a seawater temporary storage tank 44, a freshwater temporary storage tank 45, and a freshwater transfer pump 451.

[0127] During operation, the third seawater storage tank 41 introduces seawater from the sea surface using the height difference, and then the third water hammer pump 42 sends the seawater into the first freshwater condenser 40 through the height difference to condense the steam injected into the first freshwater condenser 40 by the first seawater evaporator 10 and the second seawater evaporator 20 into freshwater. The freshwater flows into the freshwater temporary storage tank 45. When the liquid level in the freshwater temporary storage tank 45 reaches the high level, the control system starts the freshwater transfer pump 451 to send the freshwater into the freshwater tank 80 for further processing. After the freshwater in the freshwater tank 80 accumulates to a certain level, it can finally be sent to the freshwater treatment plant for further processing.

[0128] 2.2 The second group of freshwater condensation systems and processes include (see [reference]). Figure 6 (as shown)

[0129] The working principle and equipment configuration of the second freshwater condensation process are exactly the same as those of the first freshwater condensation process. The relevant equipment includes: a second freshwater condenser 50, a fifth seawater storage tank 51, a fifth water hammer pump 52, a seawater buffer tank 53, a seawater temporary storage tank 54, a freshwater temporary storage tank 55, and a freshwater transfer pump 551, etc.

[0130] During operation, the fifth seawater storage tank 51 introduces seawater from the sea surface using the height difference, and then the fifth water hammer pump 52 sends the seawater into the second freshwater condenser 50 through the height difference to condense the steam injected into the second freshwater condenser 50 by the first seawater evaporator 10 and the third seawater evaporator 30 into freshwater. The freshwater flows into the freshwater temporary storage tank 55. When the liquid level in the freshwater temporary storage tank 55 reaches the high level, the control system starts the freshwater transfer pump 551 to send the freshwater into the freshwater tank 80 for further processing.

[0131] Please see Figure 7As shown above, although the solar-powered thermal depressurization evaporation seawater desalination device of this invention achieves seawater desalination by evaporating and then condensing seawater using solar thermal energy, it differs from other seawater desalination technologies in that it does not directly condense the steam generated by the first seawater evaporator 10 in the first stage. Instead, it converts this high-temperature steam into kinetic energy, which is then pumped out through the first Venturi steam ejector 24, the second Venturi steam ejector 34, the third Venturi steam ejector 35, and the connected second and third seawater evaporators 20 and 30. This reduces the internal air pressure of the second seawater evaporator 20 and the third seawater evaporator 30 to, for example, 30,000 Pa and 10,000 Pa, respectively, thereby reducing the seawater evaporation temperature to, for example, 70°C and 50°C, respectively. This allows the solar thermal concentrating pressure reducing evaporation seawater desalination device of the present invention to produce, for example, three seawater evaporation physical effects. However, its heat source is only a set of solar thermal concentrating plate assemblies 60 connected in series and a heat transfer oil conveying pipe. The final result is that all the steam generated from the three sets of seawater evaporators can be condensed in the first freshwater condenser 40 and the second freshwater condenser 50 without any leakage.

[0132] In other words, compared with the traditional solar-powered concentrated heat depressurization seawater desalination system, the present invention uses one times the heat energy to sequentially perform, for example, three seawater evaporators (10, 20, and 30) through depressurization evaporation in three stages. Although the total amount of freshwater obtained cannot be determined to be more than three times the total heat provided by the solar energy, the simultaneous operation of the three seawater evaporators (10, 20, and 30) can significantly increase the amount of freshwater produced by the three-stage evaporation process. This is certain. Compared with other technologies, this device can achieve the goal of energy saving and carbon reduction, which goes without saying.

[0133] In addition to utilizing the depressurization evaporation principle for secondary and tertiary seawater evaporation processes, the solar thermal depressurization desalination device of this invention also employs a gravity-type water hammer pump for seawater transportation. By utilizing the water hammer effect principle of the pump, positioned at a lower ground level, seawater at a higher level first flows into a seawater storage tank and is then introduced into the water hammer pump. The compression energy of the water hammer pump then propels the seawater into a high-level seawater evaporator for evaporation, or into a freshwater condenser for condensation. This minimizes energy consumption and reduces unit operating costs within the operating hours covered by sunlight, which is one of the advantages of this invention.

[0134] The above description is merely a preferred embodiment of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A solar-powered, high-pressure desalination seawater desalination device, characterized in that, include: The system comprises a solar thermal panel assembly, a first seawater evaporator, a second seawater evaporator, a first freshwater condenser, a first Venturi-type steam ejector, a first seawater storage tank, a second seawater storage tank, and a third seawater storage tank, wherein: The solar thermal panel assembly receives the heat transfer oil and raises the temperature of the heat transfer oil to a high temperature through the heat collection effect of the solar thermal panel assembly. The heat transfer oil is then transported to the first seawater evaporator and the second seawater evaporator through the heat transfer oil delivery pipe to provide the first seawater evaporator and the second seawater evaporator with heat energy to evaporate the seawater. The first Venturi-type steam ejector is connected to the first seawater evaporator, the second seawater evaporator, and the first freshwater condenser via a steam distributor. The steam generated by the first seawater evaporator drives the first Venturi-type steam ejector to evacuate the second seawater evaporator, thereby reducing the internal pressure of the second seawater evaporator. This allows the heat transfer oil, which has already been cooled down after the first stage of seawater evaporation in the first seawater evaporator, to play a role in the seawater evaporation process of the second seawater evaporator, enabling the evaporation of medium-high temperature seawater within the second seawater evaporator. The first seawater storage tank, the second seawater storage tank, and the third seawater storage tank directly introduce seawater. The first seawater storage tank is connected to a first water hammer pump to transport seawater into the first seawater evaporator. The second seawater storage tank is connected to a second water hammer pump to transport seawater into the second seawater evaporator. The third seawater storage tank is connected to a third water hammer pump to send seawater into the first freshwater condenser. The system includes a steam distributor connected above the first seawater evaporator, which is connected to several steam pipelines. The steam generated by the first seawater evaporator is transported to the steam pipelines through the steam distributor by pressure difference. One of the steam pipelines leads the steam to a second Venturi-type steam ejector, which is connected to a third seawater evaporator. Another steam pipeline leads the steam to a third Venturi-type steam ejector, which is connected to a second freshwater condenser. The negative pressure inlet of the third Venturi-type steam ejector is connected to the steam outlet of the second Venturi-type steam ejector. The device further includes a fourth seawater storage tank that directly introduces seawater, and the fourth seawater storage tank uses a fourth water hammer pump to transport the seawater into the third seawater evaporator. After the steam generated by the first seawater evaporator leaves the steam distributor, some of the steam can be introduced into the second and third Venturi-type steam ejectors connected in series through one of the steam pipelines and another steam pipeline. Since the negative pressure inlet of the third Venturi-type steam ejector is connected to the steam jet outlet of the second Venturi-type steam ejector, the nozzle pressurization effect generated by the steam jet outlet of the second Venturi-type steam ejector and the depressurization effect of the negative pressure inlet of the nozzle of the third Venturi-type steam ejector improve the steam jet extraction efficiency of the second and third Venturi-type steam ejectors connected in series. This results in a higher pressure drop inside the third seawater evaporator connected to the second Venturi-type steam ejector, thereby allowing the seawater to evaporate at a lower temperature.

2. The solar thermal depressurization evaporation seawater desalination device as described in claim 1, characterized in that, The continuously flowing heat transfer oil is fed into the heat exchanger coil inside the third seawater evaporator and transported forward. When the aforementioned heat transfer oil flows through the heat exchanger coil inside the second seawater evaporator, some of the heat energy has been taken away by the seawater evaporated in the second seawater evaporator. However, since the air pressure inside the third seawater evaporator is lower than that inside the second seawater evaporator, the seawater sprayed downwards by the seawater sprayer installed in the third seawater evaporator can evaporate at a lower temperature. The evaporated seawater turns into steam again and is drawn into the second Venturi steam ejector and the third Venturi steam ejector, and sprayed into the second freshwater condenser in the next stage for condensation and recovery as freshwater.

3. The solar thermal depressurization evaporation seawater desalination device as described in claim 2, characterized in that, The system includes a brine storage tank connected below the third seawater evaporator, a brine delivery pump connected to the brine delivery pump connected to the brine tank, and the brine storage tank is used to collect the brine falling from the third seawater evaporator.

4. The solar thermal depressurization evaporation seawater desalination device as described in claim 2, characterized in that, The system further includes a fifth seawater storage tank that directly introduces seawater. This fifth seawater storage tank uses a fifth water hammer pump to transport seawater into the third seawater evaporator. The steam generated by the third seawater evaporator is sent to the second freshwater condenser through a steam pipeline. The steam is sprayed onto the surface of the heat exchanger coil inside the second freshwater condenser by a steam sprayer installed inside the second freshwater condenser. At the same time, a fifth water hammer pump located around the second freshwater condenser continuously delivers low-temperature seawater through the heat exchanger coil inside the second freshwater condenser. Through the heat transfer effect, the steam in contact with the heat exchanger coil of the second freshwater condenser turns into freshwater and falls into a freshwater temporary storage tank located below the second freshwater condenser.

5. The solar thermal depressurization evaporation seawater desalination device as described in claim 1, characterized in that, The solar thermal panel assembly is a parabolic solar thermal panel assembly, and a heat transfer oil conduit is installed at the position where the light is reflected and focused on the top of the solar thermal panel assembly, which allows the heat transfer oil to circulate. The heat transfer oil circulation pipeline is filled with heat transfer oil, and the solar thermal panel assembly uses reflection to focus the radiant heat energy of the solar energy and project it onto the heat transfer oil circulation pipeline, so that the heat transfer oil inside the heat transfer oil circulation pipeline rises to a preset high temperature.

6. The solar thermal depressurization evaporation seawater desalination device as described in claim 1, characterized in that, The first seawater evaporator has a heat exchanger coil inside, and when the heat transfer oil flows through the first seawater evaporator, the surface of the heat exchanger coil inside the first seawater evaporator also generates high temperature. The first seawater storage tank is below the sea surface, allowing seawater to be introduced from the sea surface through the elevation difference. The seawater is then pumped into the first seawater evaporator by the first water hammer pump, utilizing the physical effect of the elevation difference. The first seawater evaporator has a seawater sprayer with multiple spray holes, which sprays seawater onto the high-temperature heat exchanger coils inside the evaporator, causing the seawater to evaporate instantly into steam. The unevaporated seawater becomes brine due to the increased salinity and falls into the brine storage tank below.

7. The solar thermal depressurization evaporation seawater desalination device as described in claim 6, characterized in that, The system includes a brine storage tank connected below the first seawater evaporator, a brine transfer pump connected to the brine transfer pump connected to a brine tank, and the brine storage tank is used to collect the brine falling from the first seawater evaporator. When the liquid level in the brine storage tank reaches a high level, the brine is then transported to the brine tank by the brine transfer pump for centralized treatment and reuse.

8. The solar thermal depressurization evaporation seawater desalination device as described in claim 1, characterized in that, The system includes a steam distributor connected above the first seawater evaporator, which is connected to multiple steam pipelines. The high-pressure steam generated by the first seawater evaporator is transported to one of the steam pipelines through the steam distributor by means of a pressure difference. The steam pipeline then introduces the steam into the first Venturi-type steam ejector. As the steam passes through the first Venturi-type steam ejector, it creates a suction effect on the second seawater evaporator connected below the first Venturi-type steam ejector, thereby creating a pressure reduction effect inside the second seawater evaporator and making it a negative pressure state. The continuously flowing heat transfer oil is introduced into the heat exchanger coil inside the second seawater evaporator and transported forward. When the aforementioned heat transfer oil flows through the heat exchanger coil inside the first seawater evaporator, some of the heat energy is taken away by the seawater evaporated by the first seawater evaporator. However, at this time, the pressure inside the second seawater evaporator is already at a low pressure, so that the seawater sprayed downwards by the seawater sprayer installed in the second seawater evaporator can evaporate at a lower temperature. Therefore, the evaporated seawater is evaporated into steam at a lower temperature, and is sucked into the first Venturi-type steam ejector and sprayed into the first freshwater condenser in the next stage for condensation and recovery into freshwater.

9. The solar thermal depressurization evaporation seawater desalination device as described in claim 8, characterized in that, The system includes a brine storage tank connected below the second seawater evaporator, a brine delivery pump connected to the brine delivery pump connected to a brine tank, and the brine storage tank is used to collect the brine falling from the second seawater evaporator.

10. The solar thermal depressurization evaporation seawater desalination device as described in claim 9, characterized in that, The steam generated by the second seawater evaporator is sent into the first freshwater condenser through a steam pipeline. The steam is sprayed onto the surface of the heat exchanger coil inside the first freshwater condenser by a steam sprayer installed inside the condenser. At the same time, the third water hammer pump, which is located around the first freshwater condenser, continuously sends room temperature seawater through the heat exchanger coil inside the condenser. Through the heat transfer effect, the steam in contact with the surface of the heat exchanger coil turns into freshwater and falls into a freshwater storage tank located below the condenser. When the freshwater storage tank reaches a high level, the pump is activated to send the freshwater to a freshwater storage tank for further processing.

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