Two-stage supercharged dehumidification system

Abstract

The application relates to a two-stage pressurized dehumidification and humidification system, which comprises a humidifier with a containing cavity containing waste water, the humidifier being used for humidifying gas entering the containing cavity; a heat exchanger assembly comprising a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger for heat exchange, the first heat exchanger being communicated with the humidifier; a compressor assembly comprising a first compressor and a second compressor for pressurizing gas, one end of the first compressor being communicated with the humidifier and the other end being communicated with the first heat exchanger; a water separator assembly comprising a first water separator and a second water separator, the first water separator being communicated with the first heat exchanger and being used for collecting clean water generated by condensation of the first heat exchanger; and the second water separator being communicated with the second heat exchanger. The two-stage pressurized dehumidification and humidification system can greatly improve the water output efficiency of the dehumidification and humidification system and enhance the industrial practicability of the dehumidification and humidification system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater recovery, and particularly relates to a two-stage pressurization dehumidification humidification-dehumidification system. BACKGROUND

[0002] In order to further improve water efficiency and save water resources, the recovery and utilization of industrial and domestic wastewater with high salt content has gradually been valued. In addition, seawater desalination technology also gradually has good potential to provide fresh water for arid regions. Industrial wastewater or seawater can be used as a salt-containing water raw material for desalination treatment and fresh water recovery.

[0003] At present, the desalination and recovery technology of salt water is relatively mature at home and abroad. Common desalination processes include reverse osmosis, multi-stage flash evaporation, low-temperature multi-effect distillation, etc. The reverse osmosis method separates salt and water by allowing water molecules to pass through the reverse osmosis membrane under the action of a high-pressure pump. However, it is limited by the performance and service life of the membrane. Traditional multi-effect distillation and multi-stage flash evaporation are difficult to be commercially popularized and used due to some common problems, such as large and complex device, large volume, and high cost.

[0004] Humidification-dehumidification (HDH) is a thermal desalination technology. This technology simulates the rainfall cycle in nature, uses flowing air as a carrier of water vapor, and exchanges heat and mass between the air and the hot feed liquid in the humidification system. After the air is heated and humidified, a certain amount of water vapor is carried into the dehumidification system to be dehumidified. By using the humidity difference of the air, the excess water vapor is condensed into fresh water, and the remaining feed liquid is concentrated. Compared with other technologies, the HDH technology has the advantages of simple structure, low cost, and the use of low-grade energy or renewable energy. At present, the HDH technology has broad application prospects in the fields of seawater desalination, industrial wastewater concentration, landfill leachate concentration treatment, and domestic sewage treatment.

[0005] However, in the existing HDH technology, the water production efficiency of the conventional humidification-dehumidification system is low, which is difficult to meet the large-scale industrial production. Therefore, there is an urgent need to propose a humidification-dehumidification system with good performance to improve its water production efficiency. SUMMARY

[0006] Therefore, the embodiments of the present application provide a two-stage pressurization dehumidification humidification-dehumidification system, which aims to improve the water production efficiency of the humidification-dehumidification system.

[0007] The two-stage pressurization dehumidification humidification-dehumidification system provided by the embodiments of the present application comprises:

[0008] a humidifier having a containing cavity containing wastewater, the humidifier being configured to humidify gas entering the containing cavity;

[0009] a heat exchanger assembly comprising a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger for exchanging heat, the first heat exchanger being in communication with the humidifier;

[0010] a compressor assembly comprising a first compressor and a second compressor for compressing gas, one end of the first compressor being in communication with the humidifier and the other end being in communication with the first heat exchanger;

[0011] a water separator assembly comprising a first water separator and a second water separator, the first water separator being in communication with the first heat exchanger and being used for collecting clean water produced by condensation in the first heat exchanger, the second water separator being in communication with the second heat exchanger and being used for collecting clean water produced by condensation in the second heat exchanger, wherein

[0012] the third heat exchanger being in communication with the first heat exchanger;

[0013] one end of the second compressor being in communication with the first water separator and the other end being in communication with the fourth heat exchanger;

[0014] the second heat exchanger being in communication with the fourth heat exchanger.

[0015] In some embodiments, the two-stage pressurized dehumidification and humidification system further comprises a water pump in communication with the third heat exchanger, the water pump being used for pumping external waste water into the third heat exchanger, the external waste water passing through the third heat exchanger into the first heat exchanger, the first heat exchanger being used for transferring heat of the gas compressed by the first compressor to the external waste water, and discharging the heated external waste water to the humidifier.

[0016] In some embodiments, one end of the third heat exchanger is further in communication with a water discharge port of the humidifier, the third heat exchanger being used for transferring heat of the concentrated waste water discharged by the humidifier to the external waste water.

[0017] In some embodiments, the second heat exchanger comprises a first inlet and a first outlet, the first inlet being in communication with the fourth heat exchanger, the two-stage pressurized dehumidification and humidification system further comprising a turbine having an input port in communication with the second water separator, the other end of the second water separator being in communication with the first outlet, the turbine being used for absorbing internal energy of the gas discharged by the second heat exchanger and converting the internal energy into mechanical energy and outputting to the second compressor.

[0018] In some embodiments, the turbine further comprises an output port, the second heat exchanger further comprising a second inlet and a second outlet, the second inlet being in communication with the output port, and the second outlet being in communication with the fourth heat exchanger.

[0019] In some embodiments, the fourth heat exchanger comprises a third inlet, a third outlet, a fourth inlet and a fourth outlet, wherein the third inlet is in communication with the second compressor, the third outlet is in communication with the first inlet, the fourth inlet is in communication with the second outlet, and the fourth outlet is in communication with the humidifier.

[0020] In some embodiments, the two-stage supercharged dehumidification humidification and dehumidification system further comprises a driver for powering the first compressor.

[0021] In some embodiments, the humidifier comprises:

[0022] a housing enclosing the accommodation cavity;

[0023] a filling member arranged in the accommodation cavity, the filling member being provided with fine gas passages.

[0024] The two-stage supercharged dehumidification humidification and dehumidification system according to the embodiments of the present application comprises a humidifier, a heat exchanger assembly, a compressor assembly and a water separator assembly. The humidifier has an accommodation cavity for accommodating waste water. When gas enters the accommodation cavity, it can take away part of the water in the waste water. The gas carrying the water is pressurized by the first compressor, and then condensed into liquid water in the first heat exchanger, and collected by the first water separator. Thereafter, the gas is pressurized by the second compressor, and then condensed into liquid water in the second heat exchanger, and collected by the second water separator. In this way, the water in the waste water is taken away by the gas and then subjected to pressurization and condensation twice, which can greatly improve the water output efficiency of the humidification and dehumidification system and enhance the industrial practicability of the humidification and dehumidification system. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art without creative labor.

[0026] Figure 1 a schematic diagram of an HDH system in the prior art;

[0027] Figure 2 a schematic diagram of another HDH system in the prior art;

[0028] Figure 3 a schematic diagram of another HDH system in the prior art;

[0029] Figure 4 a schematic diagram of another HDH system in the prior art;

[0030] Figure 5 The diagram shows the system principle of a two-stage pressurized dehumidification system provided in some embodiments of this application.

[0031] The accompanying drawings may not be drawn to scale.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Humidifier; 11. Outer casing; 12. Filling components;

[0034] 21. First heat exchanger; 22. Second heat exchanger; 221. First inlet; 222. First outlet; 223. Second inlet; 224. Second outlet; 23. Third heat exchanger; 24. Fourth heat exchanger; 241. Third inlet; 242. Third outlet; 243. Fourth inlet; 244. Fourth outlet;

[0035] 31. First compressor; 32. Second compressor;

[0036] 41. First water separator; 42. Second water separator;

[0037] 5. Water pump; 6. Turbine; 7. Drive. Detailed Implementation

[0038] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0039] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0040] It is to be understood that the embodiments described hereinbelow within the scope of the appended claims. It will be apparent to one of ordinary skill in the art that aspects described herein can be implemented in a wide variety of forms, and that any specific structure and / or function described herein is merely illustrative. An aspect described herein can be implemented alone or in combination with any other aspect(s). For example, an apparatus can be implemented using any number of the aspects set forth herein. Additionally, an apparatus can be implemented using other structure and / or functionality.

[0041] It is also to be understood that the diagrams provided in the following embodiments are only schematic and that the dimensions of the various components in the drawings can be exaggerated for clarity. The actual implementation can vary from the description and / or diagram.

[0042] In addition, in the following description, numerous specific details are set forth in order to provide a thorough understanding of the examples. However, it will be apparent to one of ordinary skill in the art that the aspects can be practiced without these specific details.

[0043] Figure 1 A schematic diagram of an HDH system.

[0044] As shown in Figure 1 , the left side is a humidifier, and the right side is a dehumidifier. The seawater 1 enters the dehumidifier, cools the humid air, and causes the moisture to condense and flow out, obtaining fresh water 5. Then the seawater enters the heater at point 2, is heated, and is sent to the humidifier, sprayed in the filler material inside the humidifier. The air a1 enters the humidifier under the action of the pump, exchanges heat and moisture with the hot seawater in the internal filler material, absorbs heat and moisture, carries a certain amount of water vapor, and is sent back to the dehumidifier, where it is cooled by seawater and condensed to obtain fresh water. Compared with other seawater desalination systems or wastewater treatment systems, Figure 1 The water output efficiency of the HDH system shown is low. If measured by the gain output ratio (GOR), the GOR is only about 0.7-1.9.

[0045] Figure 2 A schematic diagram of another HDH system.

[0046] To improve the water output efficiency, researchers have improved the HDH system, such as using low-grade energy or renewable energy, solar energy being one of them, or combining the HDH system with heat pump technology, for example Figure 2An HDH system is shown, which employs a heat pump to couple two-stage dehumidification, and the GOR can reach 2.5. Specifically, in Figure 2 the seawater is first pumped into the dehumidifier (1→2) to cool the humid air of the humidifier (13→14), and then enters the dehumidifier (2→3), where the humid air of the humidifier is condensed (10→11), and the condensed water (20 and 21) generated in the dehumidifier is collected. After leaving the dehumidifier, the seawater is further heated by the waste water in the heater (3→4), and then is delivered to the top of the humidifier. In the humidifier, the seawater is sprayed on the filler material (4→5), while the air from the dehumidifier enters the evaporator of the heat pump to be further cooled and dehumidified (11→12), and then flows into the humidifier and exchanges heat and mass with the seawater (12→10), thereby increasing the temperature and humidity. Accordingly, the brine from the bottom of the humidifier is further heated by the condenser of the heat pump (5→8). Seawater can be supplemented before the condenser to mix with the brine (7→6) to reduce the temperature of state 6. After leaving the condenser, the brine is sent into the humidifier to exchange heat and mass with the air from the dehumidifier (8→9), so that the air is heated and humidified (14→13), and finally the brine is discharged from the bottom of the humidifier, and the humid air is delivered to the dehumidifier, thereby forming a closed air-open water cycle. However, the use of heat pump technology further increases the power consumption of the HDH system, and the GOR cannot be effectively improved.

[0047] Figure 3 A schematic diagram of another HDH system is shown.

[0048] As Figure 3 shown, another measure to improve the dehumidification technology is to develop from a constant-pressure system to a variable-pressure system, for example, to use a compressor and a throttle valve to realize the variable-pressure process of air, and no longer use an additional air heater or water heater. When the pressure ratio is 1.33, the GOR can reach 3.8. Specifically, the seawater enters the cooling coil in the dehumidifier and remains at atmospheric pressure, absorbs the latent heat of the humid air outside the tube, and leaves the dehumidifier at a higher temperature. Then the seawater is sprayed on the filler material in the humidifier and exchanges heat and mass with the air, and the non-evaporated water leaves the humidifier as brine. After leaving the dehumidifier, the air is expanded in the throttle valve, the pressure is reduced, and the expansion also causes part of the water to condense out and be further collected. The air after pressure reduction enters the humidifier and exchanges heat and mass with the seawater, carries part of the evaporated water out, enters the compressor, is compressed to a higher pressure and temperature, and then enters the dehumidifier. The pressurized air is cooled in the dehumidifier, the heat is transferred to the seawater flowing in the tube, the water is condensed and collected, and then the cycle continues. However, the use of high-energy-consuming devices such as compressors also increases the power consumption of the system, which is not conducive to the improvement of the GOR of the system.

[0049] Figure 4 A schematic diagram of another HDH system is shown.

[0050] Figure 4 The figure shows a schematic diagram of a heat pump coupled variable pressure HDH system. Seawater 1 enters the heat exchanger and exchanges heat with hot air 5 from the outlet of the compressor, completing the preheating. The preheated water flows into the solar water heater and is heated to the required temperature. Then, the heated water 3 enters the humidifier and exchanges heat and moisture with the air, and the air carries away part of the moisture and cools down. The concentrated brine 15 is discharged from the humidifier. The brine enters the metal tank for storage and maintains the vacuum in the humidifier. The humid air 4 enters the compressor and is compressed, increasing the pressure and temperature. The pressurized air 5 then enters the heat exchanger and cools down. The condensed moisture 7 is separated and collected in the separator 1. The dehumidified air 8 enters the heat exchanger and is cooled by air 12, then enters the evaporator for further cooling. The condensed moisture 11 is separated and collected in the separator 2. The second dehumidified air 12 returns to the heat exchanger to cool air 8, then passes through the throttle valve to reduce the pressure and returns to the humidifier to continue the next cycle. After the pressure in the humidifier is reduced to the required value, the liquid ring vacuum pump is turned off, and the humidifier pressure is adjusted by the throttle valve. However, this system uses high-energy-consuming devices such as vacuum pumps, which also increases the power consumption and is not conducive to improving the system GOR.

[0051] In view of the above problems, the present application provides a two-stage pressurized dehumidification humidification and dehumidification system, which can effectively enhance the dehumidification capacity of the humidification and dehumidification system, thereby improving the water efficiency and the GOR of the system.

[0052] Figure 5 The system principle diagram of the two-stage pressurized dehumidification humidification and dehumidification system provided for some embodiments of the present application.

[0053] As shown in Figure 5 The high-salinity wastewater is pushed into the cold side of the third heat exchanger 23 (1w→2w) by the water pump 5 and exchanges heat with the concentrated wastewater on the hot side. Since the temperature of the concentrated wastewater is higher than that of the high-salinity wastewater, the high-salinity wastewater is heated and its temperature is increased in the third heat exchanger 23. Then, the high-salinity wastewater exchanges heat with the high-temperature and high-pressure humid air from the outlet of the first air compressor 31 in the cold side of the first heat exchanger 21 (2w→3w). The high-salinity wastewater is further heated and its temperature is continuously increased in the first heat exchanger 21. Then, the high-salinity wastewater is sent into the humidifier 1 and sprayed on the filling member 12 in the humidifier 1 to exchange heat and moisture with the incoming humid air (3w→4w). The remaining concentrated wastewater is discharged from the humidifier 1 and enters the hot side of the third heat exchanger 23 to heat the high-salinity wastewater (4w→5w). It should be noted that the humidifier 1 of the present application can have a shell 11, and the filling member 12 can be arranged in the accommodating cavity enclosed by the shell 11, and the filling member 12 has fine gas passages formed thereon.

[0054] The incoming wet air exchanges heat and mass with the high-salinity wastewater sprayed on the filling member in the humidifier 1 (1a→2a), absorbs the heat of the high-salinity wastewater, and is warmed and humidified, and then is compressed in the first air compressor 31 (2a→3a), further increasing the pressure and temperature. The first air compressor 31 can be driven by the driver 7. The high-temperature and high-pressure wet air exchanges heat with the high-salinity wastewater in the hot side of the first heat exchanger 21 (3a→4a), is cooled and cooled, and the condensed water is separated in the first water separator 41 (4a→5a→6w) and is collected. It should be noted that the driver 7 can be various driving mechanisms or driving devices, such as motors or internal combustion engines, etc. Exemplarily, in the present application, the driver 7 can be a motor.

[0055] Then, the part of the wet air is further compressed in the second air compressor 32 (5a→6a), and the pressure and temperature are increased for the second time. The high-temperature and high-pressure wet air enters the fourth heat exchanger 24 through the third inlet 241, flows out from the third outlet 242 after heat exchange in the fourth heat exchanger 24, and then enters the second heat exchanger 22 through the first inlet 221, flows out from the first outlet 222 after heat exchange in the second heat exchanger 22. The water condensed in the fourth heat exchanger 24 and the second heat exchanger 22 is separated in the second water separator 42 (8a→9a→7w) and is further collected.

[0056] The high-temperature and high-pressure wet air after dehumidification is sent to the turbine 6 (9a→10a), expands to do work and cools in the turbine 6, realizes pressure reduction and temperature reduction, and the turbine 6 outputs work to drive the second air compressor 32 to work. Subsequently, the part of the low-temperature and low-pressure wet air enters the cold side of the second heat exchanger 22 and the fourth heat exchanger 24 in turn through the second inlet 223, the second outlet 224, the fourth inlet 243, and the fourth outlet 244 (10a→11a→1a), is used to cool the high-temperature and high-pressure wet air in the hot side, and at the same time, absorbs the heat of the hot side to increase the temperature, and then is sent back to the humidifier 1 to continue the next humidification and dehumidification cycle. The above working cycle forms a closed air-open water humidification and dehumidification cycle.

[0057] In the above humidification and dehumidification cycle, the water in the high-salinity wastewater enters the wet air, is separated by two-stage pressurization and two-stage condensation, and is finally collected, which enhances the dehumidification capacity of the system, realizes desalination and collection, further improves the water production rate, and the turbine 6 expansion work also drives the second air compressor 32 to work, recovers energy, and reduces the power consumption of the system.

[0058] The two-stage pressurization dehumidification system of the embodiment of the application can effectively improve the water output efficiency and enhance the dehumidification capacity. It can be understood that the two-stage pressurization dehumidification is only one preferred setting of the application, which can effectively improve the water output efficiency and dehumidification capacity of the system without increasing the complexity of the system too much. Of course, in some cases, the system of the application can also be improved, for example, a more-stage pressurization dehumidification system is used to further enhance the dehumidification capacity and water output efficiency of the system.

[0059] The two-stage pressurization dehumidification system of the embodiment of the application has at least the following advantages:

[0060] 1. Two compressors are used to realize two-stage pressurization, which can achieve higher pressure compared with single-stage pressurization, enhance the dehumidification capacity of the system, and further improve the condensation water output rate.

[0061] 2. A turbine is used instead of a throttle valve to realize pressure reduction and temperature reduction of air and recover the expansion work of the gas. The expansion work can be used to drive the compressor to work, reduce the power consumption of the system, and further improve the GOR.

[0062] 3. The heat pump system is cancelled, and no refrigerant is needed, so that the system operation and maintenance are more environmentally friendly.

[0063] 4. In the current variable pressure HDH research, air is directly introduced into the humidifier after being expanded and cooled by the throttle valve. At this time, the air temperature is at the lowest state, and the cooling capacity is strong. The application utilizes this feature, and the air is also expanded and cooled by the turbine to the lowest temperature, and then introduced into the heat exchanger to cool the high-temperature and high-pressure wet air, improve the condensation water output, and enhance the dehumidification capacity. This makes the moisture content of the wet air returned to the humidifier further reduced compared with the current variable pressure HDH system, and the temperature of the air is also increased by heat recovery in the heat exchanger. After returning to the humidifier, the water evaporation rate and the air moisture absorption capacity will also be improved, and the humidification effect will also be enhanced.

[0064] 5. A clever pipe connection method is used to fully utilize the heat exchange of the gas and liquid water in the system in each process, maximize the energy consumption, and be conducive to energy saving and emission reduction.

[0065] In accordance with the embodiments of the application described above, these embodiments are not meant to be exhaustive or limiting of the application. Many modifications and variations of the described embodiments will be apparent to those of ordinary skill in the art having the benefit of the teachings of this application. It is intended that the scope of the application encompass these and all such modifications and variations.

Claims

1. A two-stage pressurized dehumidification system, characterized in that, include: A humidifier having a containment chamber for containing wastewater, the humidifier being used to humidify the gas entering the containment chamber; A heat exchanger assembly including a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger for heat exchange, wherein the first heat exchanger is in communication with the humidifier; A compressor assembly includes a first compressor and a second compressor for pressurizing gas, one end of the first compressor being connected to the humidifier and the other end being connected to the first heat exchanger; A water separator assembly includes a first water separator and a second water separator. The first water separator is connected to a first heat exchanger and is used to collect purified water condensed by the first heat exchanger. The second water separator is connected to a second heat exchanger and is used to collect purified water condensed by the second heat exchanger. The third heat exchanger is connected to the first heat exchanger; One end of the second compressor is connected to the first water separator, and the other end is connected to the fourth heat exchanger; The second heat exchanger is connected to the fourth heat exchanger.

2. The two-stage pressurized dehumidification system according to claim 1, characterized in that, The two-stage pressurized dehumidification system also includes a water pump connected to the third heat exchanger. The water pump is used to pump external wastewater into the third heat exchanger. The external wastewater enters the first heat exchanger after passing through the third heat exchanger. The first heat exchanger is used to transfer the heat of the gas pressurized by the first compressor to the external wastewater and discharge the heated external wastewater to the humidifier.

3. The two-stage pressurized dehumidification system according to claim 2, characterized in that, One end of the third heat exchanger is also connected to the drain outlet of the humidifier. The third heat exchanger is used to transfer the heat of the concentrated wastewater discharged from the humidifier to the external wastewater.

4. The two-stage pressurized dehumidification system according to claim 1, characterized in that, The second heat exchanger includes a first inlet and a first outlet. The first inlet is connected to the fourth heat exchanger. The two-stage pressurized dehumidification system also includes a turbine. The turbine has an inlet that is connected to the second water separator. The other end of the second water separator is connected to the first outlet. The turbine is used to absorb the internal energy of the gas discharged through the second heat exchanger and convert the internal energy into mechanical energy before outputting it to the second compressor.

5. The two-stage pressurized dehumidification system according to claim 4, characterized in that, The turbine also includes an output port, and the second heat exchanger also includes a second inlet and a second outlet. The second inlet is connected to the output port, and the second outlet is connected to the fourth heat exchanger.

6. The two-stage pressurized dehumidification system according to claim 5, characterized in that, The fourth heat exchanger includes a third inlet, a third outlet, a fourth inlet, and a fourth outlet. The third inlet is connected to the second compressor, the third outlet is connected to the first inlet, the fourth inlet is connected to the second outlet, and the fourth outlet is connected to the humidifier.

7. The two-stage pressurized dehumidification system according to claim 1, characterized in that, The two-stage pressurized dehumidification system also includes a driver that provides power to the first compressor.

8. The two-stage pressurized dehumidification system according to any one of claims 1 to 7, characterized in that, The humidifier includes: The outer shell encloses and forms the receiving cavity; A filling member is disposed within the receiving cavity, and fine gas channels are formed on the filling member.

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