Solar energy based integrated system and method for desalination, drying and salt extraction

Abstract

The application discloses a solar energy-based desalination-water-drying-salt extraction integrated system and method, which comprises a solar vacuum tube desalination water system, a solar main and cover integrated drying system, a valley electricity assisted solar salt extraction-desalination water system and a control system; the solar vacuum tube desalination water system is connected with the valley electricity assisted solar salt extraction-desalination water system and sends concentrated liquid to the valley electricity assisted solar salt extraction-desalination water system; and the solar vacuum tube desalination water system is connected with the solar main and cover integrated drying system and sends dry hot air to the solar main and cover integrated drying system. The system utilizes solar energy to drive desalination water and dry agricultural or fishery products during the day, simultaneously achieving the purposes of producing fresh water, obtaining concentrated liquid and drying fresh materials; the valley electricity is utilized to further distill the concentrated liquid during the night, thereby simultaneously achieving the purposes of producing fresh water and obtaining deeply concentrated liquid; the next day, the passive solar distillation structure is utilized to deeply extract water in the concentrated liquid during the sunrise-sunset period, thereby simultaneously obtaining fresh water and salt-containing by-products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar energy cascade diversification and efficient utilization, in particular to a desalination water-drying-salt extraction integrated system and method based on solar energy supply. BACKGROUND

[0002] Fresh water resources are the material basis for human survival and development. On the one hand, the proportion of directly usable fresh water resources in the world is very small, while the demand for fresh water by human society is increasing year by year, resulting in a persistent supply-demand contradiction of global fresh water resources; on the other hand, China's fresh water resources have the characteristics of uneven spatial distribution, resulting in regional supply-demand contradictions. Therefore, solving the contradiction between supply and demand of fresh water resources is an urgent task for China and even the world.

[0003] Firstly, seawater / brackish water / chemical plant wastewater desalination is one of the effective measures to solve the regional contradiction between supply and demand of fresh water resources, and the traditional method consumes a large amount of fossil or electric energy. In order to overcome the problems of high energy consumption and lack of regional fossil or electric energy in traditional desalination method, solar energy efficient desalination technology can be developed in areas with abundant solar energy resources.

[0004] Secondly, most of the land brackish water areas belong to agricultural and pastoral product production areas, and drying is a necessary and important link in the production process of agricultural and pastoral products. There are also many agricultural production areas around chemical plants, which also have drying needs. In addition, Gansu, Xinjiang, Inner Mongolia and Ningxia have large reserves of brackish water and abundant solar energy resources, and island areas have large reserves of seawater and abundant solar energy resources, so the above-mentioned areas can realize the integrated operation of solar-driven desalination and drying.

[0005] Finally, in the process of desalinating brackish water / seawater / chemical plant wastewater using solar energy, not only fresh water can be produced, but also concentrated liquid can be produced. The concentrated liquid is a waste product, and if it is not treated, it will pollute the environment or cause secondary treatment costs. Therefore, based on the sensible heat carried by the concentrated liquid, a method combining off-peak electricity and passive solar distillation structure can continuously and efficiently evaporate the water in the concentrated liquid, further obtaining a large amount of fresh water and deeply extracting salt-containing by-products with certain economic value.

[0006] In summary, it is of great significance to develop an efficient desalination-drying-salt extraction integrated system based on solar energy supply to solve the contradiction between supply and demand of fresh water resources, improve the utilization rate of solar energy, and improve the economic efficiency of the system.

[0007] A solar-based desalination water and hot water coupling system (application number: 2018108221424) uses a vaporization surface smooth type solar vacuum tube for direct heating distillation to simultaneously produce high temperature and high pressure steam and hot water. The internal cavity of the solar vacuum tube is divided into a sunning cavity and an air drying cavity by the raw water liquid surface, and the vaporization surface is the inner surface of the solar vacuum tube corresponding to the sunning cavity and the vapor-liquid interface. The high temperature and high pressure steam condensation link realizes the dual purposes of "fresh water output" and "waste heat recovery to output hot water". On the one hand, the vaporization surface smooth type solar vacuum tube distillation technology has the advantages of traditional passive and active solar distillation technology, and has relatively good water / heat production performance, but still does not have the unit water production required for large-scale application, which is ultimately caused by the low boiling vaporization intensity of the vacuum tube vaporization cavity pool (essentially caused by the low vaporization surface foaming core number and low steam bubble nucleation / detachment rate). On the other hand, the system uses water as the condensing medium, which can only use "recycled heat" to produce unstable temperature hot water, and cannot be used in the drying field of agricultural / pastoral / fishery industry which has strict requirements on the temperature of dry working medium. In addition, the system does not consider the post-treatment of concentrated liquid and the cleaning of dirt in the vaporization cavity. The thickness of the dirt on the vaporization surface will continue to increase, thereby affecting the heat transfer efficiency of the vaporization surface, resulting in continuous reduction of the vaporization rate and solar energy utilization rate.

[0008] In order to improve the unit water production, a solar heat film coupled desalination water device (application number: 2020109893996) emerges as the times require. First, the device uses a double-pass solar vacuum tube for thermal distillation, and a microporous dropper and a high-temperature resistant hydrophilic fiber coated on the microporous dropper are arranged in the double-pass solar vacuum tube. Although the vaporization intensity is relatively improved, a new vaporization surface is added, which leads to the increase of system complexity, failure rate and initial investment cost; secondly, the device still does not consider the treatment of concentrated liquid, which may result in continuous reduction of vaporization rate and solar energy utilization rate and finally block the microporous dropper; finally, the device uses a heat film coupling method, which improves the solar energy utilization rate, but only has the function of desalination water. SUMMARY

[0009] In order to meet the above-mentioned related application requirements and solve the related technical problems, the present application provides a desalination water-drying-salting integrated system and method based on solar energy supply.

[0010] The technical scheme adopted by the present application to solve its technical problems is:

[0011] A desalination water-drying-salting integrated system based on solar energy supply is provided, which comprises a solar vacuum tube desalination water system, a solar main and passive integrated drying system, a valley electricity assisted solar salting-desalination water system and a control system.

[0012] The solar vacuum tube water desalination system is connected with the valley electricity auxiliary solar salt extraction and water desalination system, and transports the concentrated liquid to the system, so that the concentrated liquid is separated into low-temperature liquid fresh water and salt-containing byproducts in the system.

[0013] The solar vacuum tube water desalination system is connected with the solar main-body integrated drying system, and transports dry hot air to the system, so that the dry hot air is used for drying materials in the system.

[0014] The control system controls the operation of the whole system.

[0015] Further, the solar vacuum tube water desalination system is a micro-porous structure type solar vacuum tube water desalination system, which is sequentially composed of a liquid level control unit, a micro-porous structure type solar evaporation unit, a phase change condensation heat recovery device and a fresh water collection bottle.

[0016] Further, the liquid level control unit comprises a water storage pool which is supported by a support; a liquid level sensor is arranged in the water storage pool, and the water storage pool is supplied with water through a liquid level control communication pipeline;

[0017] Alternatively, the micro-porous structure type solar evaporation unit comprises a header and a plurality of micro-porous structure type solar vacuum tubes, and the header is in communication with the lower part of each micro-porous structure type solar vacuum tube.

[0018] Alternatively, the phase change condensation heat recovery device comprises a steam passage corresponding to each micro-porous structure type solar vacuum tube, and the steam passage is flanked by air ducts, air passing through the air ducts can enter a solar main-body integrated drying chamber under the transportation and regulation of a dry hot air transportation and regulation fan set; a phase change-condensation temperature control cavity is further arranged between the air ducts and the steam passage, a fresh water collection cavity is in communication with the lower part of the phase change-condensation temperature control cavity, and a fresh water collection bottle is in communication with the lower part of the fresh water collection cavity.

[0019] Further, the header comprises a header body and blocking plates connected to the two sides of the header body, three concentrated liquid discharge pipes and connection ports corresponding to the micro-porous structure type solar vacuum tubes are arranged in the header body, and the concentrated liquid discharge pipes are arranged at the middle positions of the front-rear direction of the header body and are arranged at equal arc degrees.

[0020] Alternatively, the header is supported by front supports, the micro-porous structure type solar vacuum tubes are supported by rear supports, the front supports are provided with a plurality of header support grooves, angle steel inclined legs are connected to the lower parts of the header support grooves, front supports are connected to the lower parts of the angle steel inclined legs, a concentrated liquid discharge pipe orientation adjustment slot is arranged in the header support groove of the middle front support, and the height of the rear support is adjustable.

[0021] Or, the steam channel is provided with a steam nozzle between the steam outlet pipe of the corresponding micro-porous cavity structure type solar vacuum tube;

[0022] Or, the fresh water collection cavity is a semi-circular table type with a large front and a small rear, and is fixedly connected to the bottom surface of the phase change condensation-temperature control cavity. The cavity is communicated with all the steam channels and has a certain inclination from rear to front.

[0023] Further, the solar main-body integrated drying system is sequentially composed of a wet heat recovery device, a phase change condensation heat recovery device, a dry hot air conveying and adjusting fan group, a solar main-body integrated drying chamber, a wet hot air drainage and adjusting fan group, a square air duct, a wet hot air pressurizing and adjusting fan through a connecting flange, and further includes a support group.

[0024] The phase change condensation heat recovery device is communicated with the micro-porous cavity structure type solar evaporation unit.

[0025] Further, the wet heat recovery device is located above the wet hot air pressurizing and adjusting fan, and includes a dehumidifying and dust filtering net, a wind collecting port, a preheating air channel and a wet hot air channel. The dehumidifying and dust filtering net is installed at the wind collecting port. The preheating air channel is provided with a plurality of left and right open cavity structures. The preheating air channels located on both sides are communicated with a wet hot air outlet. The preheating air channel located in the middle is communicated with a wet hot air inlet. The wet hot air inlet is communicated with the micro-porous cavity structure type solar evaporation unit. The wet hot air pressurizing and adjusting fan is located at the wet hot air inlet.

[0026] Or, the solar main-body integrated drying chamber is provided with a double-layer light-transmitting tempered glass at the upper part, which is fixedly supported by a light-transmitting surface support and is installed towards the south and inclined according to the local latitude. The lower part is connected with the wet hot air drainage and adjusting fan group. The solar main-body integrated drying chamber is provided with a material tray sliding rail support. The dry hot air flows into the drying chamber through a dry hot air inlet and is discharged through a wet hot air outlet under the joint regulation of the dry hot air conveying and adjusting fan group and the wet hot air drainage and adjusting fan group.

[0027] Further, the valley electricity assisted solar salt extraction and desalination water system is sequentially composed of a micro-porous cavity structure type solar evaporation unit, a concentrated liquid treatment unit and a fresh water collection unit. The concentrated liquid discharge pipeline of the header is connected with the micro-porous cavity structure type solar vacuum tube desalination water unit and the concentrated liquid treatment unit. The sensible heat carried by the concentrated liquid produced by the micro-porous cavity structure type solar vacuum tube desalination water link can be fully utilized. The water in the concentrated liquid is continuously evaporated in time periods by using valley electricity and passive solar distillation structure.

[0028] Further, the concentrated liquid treatment unit comprises a concentrated liquid discharge pipeline, a concentrated liquid treatment pool and a passive solar distillation structure; one end of the concentrated liquid discharge pipeline is connected with the concentrated liquid discharge pipe of the header tank, and the other end is connected with the concentrated liquid treatment pool;

[0029] The concentrated liquid treatment pool is an underground pool body, and internally provided are forward stirring impellers and reverse stirring impellers.

[0030] The passive solar distillation structure comprises a support heat preservation enclosure structure extending out of the concentrated liquid treatment pool, and a double-layer light-transmitting tempered glass is arranged at the top of the support heat preservation enclosure structure; a condensing fan set is arranged above the double-layer light-transmitting tempered glass, and the double-layer light-transmitting tempered glass is supported by a hydraulic lifting mechanism and controlled in the lifting process.

[0031] Further, the fresh water collecting unit comprises a fresh water collecting pool and a fresh water supply unit; the fresh water collecting pool is used for storing the fresh water collected by the water collecting arc plate, is an underground rectangular cuboid storage pool, and is communicated with the passive solar distillation structure through a water guide pipe; the water guide pipe comprises a vertical part and an inclined part.

[0032] The integrated system carries out a method for desalination, drying and salt extraction, comprising:

[0033] System integration method: solar desalination, solar drying and auxiliary solar deep salt extraction coupled with the desalination water section to realize the gradient and diversified coupling utilization of solar energy.

[0034] Pool boiling vaporization performance enhancement method: a multi-effect enhancement method of hydrophobic modification of the vaporization surface and construction of micro-cavity structure is adopted to construct a solar vacuum tube inner wall vaporization surface with optimal contact angle, optimal micro-cavity structure shape and optimal combination of characteristic sizes.

[0035] Dry hot air temperature regulation method: a method of mutual feedback regulation of air volume at the inlet and outlet of the phase change condensation heat recovery device is adopted, and the dry cold air is preheated by the wet hot air discharged from the solar main and passive integrated drying chamber to preliminarily improve the solar utilization rate and the temperature of the preheated dry air entering the inlet of the phase change condensation heat recovery device.

[0036] Salt-containing byproduct separation method: a multi-method time sequence separation method is adopted, and the sensible heat carried by the concentrated liquid produced by the micro-cavity structure type solar vacuum tube is removed at the night valley electricity price period to obtain a preliminary concentrated liquid; on the next day, the preliminary concentrated liquid is further heated by the passive solar distillation method to remove the remaining water in the concentrated liquid to obtain a salt-containing byproduct without water.

[0037] Compared with the prior art, the beneficial effects of the present application are that:

[0038] 1. A multi-effect enhancement method using hydrophobic modification to construct micro-cavity structure, according to the use scenario, the micro-cavity structure with the best shape and the best characteristic size combination is constructed at the vaporization surface, and the vaporization surface inside the vaporization cavity is modified to greatly improve the foaming core number of the vaporization surface and the steam bubble nucleation / detachment rate, thereby improving the pool boiling vaporization intensity and the heat transfer coefficient;

[0039] 2. The phase change condensation heat recovery temperature control method synchronously realizes high-temperature steam condensation water production, on-demand production of constant-temperature dry hot air and low-temperature phase change heat storage purposes. On the one hand, according to the type of fresh materials, select the appropriate phase change heat storage material, and then adjust the temperature of the dry hot air entering the dry hot air inlet to the appropriate range to achieve efficient and high-quality drying and efficient use of solar energy. The specific process is as follows: first, use the dry hot air discharged from the drying chamber to preheat the dry cold air to obtain preheated dry air, and then use the recovered "condensation heat" to heat the preheated dry air at a constant temperature;

[0040] 3. The high-efficiency desalination-drying-salt extraction integrated system based on solar energy supply realizes the gradient and multi-element coupling utilization of solar energy. The solar desalination link, the solar drying link and the valley electricity assisted solar salt extraction-desalination link are closely coupled. Among them, the phase change condensation heat recovery device couples the micro-cavity structure type solar vacuum tube desalination and the solar main and auxiliary drying link, and the micro-cavity structure type solar evaporation unit (the concentrated liquid discharge pipeline of the header) couples the micro-cavity structure type solar vacuum tube desalination and the valley electricity assisted solar deep salt extraction-desalination link, which greatly improves the solar energy utilization rate, the operation reliability and the system economy, realizes the functional diversification, and has strong universal applicability;

[0041] 4. Based on the sensible heat carried by the concentrated liquid generated in the micro-cavity structure type solar vacuum tube, the water in the concentrated liquid is evaporated by the wall-mounted electric heating plate driven by valley electricity at night, and the fresh water is collected in the fresh water collection pool to realize the purpose of further concentration and fresh water production. The next day, the water in the concentrated liquid is further evaporated by the passive solar distillation method, and the fresh water is also collected in the fresh water collection pool, while the salt-containing by-products with certain economic value are deeply extracted. This process not only further improves the solar energy utilization rate, but also further improves the system economy and practical value. BRIEF DESCRIPTION OF DRAWINGS

[0042] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings:

[0043] Figure 1 is a structural schematic diagram of the present application;

[0044] Figure 2 is a three-view diagram of the liquid level control unit;

[0045] Figure 3 Fig. 1 is a schematic diagram of a micro-cavity structure type solar water desalination system;

[0046] Figure 4 Fig. 2 is a three-view diagram of a header;

[0047] Figure 5 Fig. 3 is a micro-cavity structure cross-sectional shape type diagram;

[0048] Figure 6 Fig. 4 is a micro-cavity structure cross-sectional feature size diagram;

[0049] Figure 7 Fig. 5 is a schematic diagram of a front bracket;

[0050] Figure 8 Fig. 6 is a partial view of a rear bracket;

[0051] Figure 9 Fig. 7 is a three-view diagram of a phase change condensing heat recovery device;

[0052] Figure 10 Fig. 8 is a three-view diagram of a wet heat recovery device;

[0053] Figure 11 Fig. 9 is a schematic diagram of a dry heat air supply and conditioning fan unit;

[0054] Figure 12 Fig. 10 is a three-view diagram of a solar main and cover integrated drying chamber;

[0055] Figure 13 Fig. 11 is a three-view diagram of a material tray;

[0056] Figure 14 Fig. 12 is a three-view diagram of a wet heat air induction and conditioning fan unit;

[0057] Figure 15 Fig. 13 is a schematic diagram of a valley electricity assisted solar salt extraction and desalination water system;

[0058] Figure 16 Fig. 14 is a principle diagram of energy and mass transfer;

[0059] Figure 17 Fig. 15 is an azimuth diagram.

[0060] In the figures:

[0061] I - micro-cavity structure type solar vacuum tube desalination water system

[0062] 1 - liquid level control unit;

[0063] 11 - water storage pool, 12 - liquid level sensor, 13 - liquid level control communication pipeline;

[0064] 2 - micro-cavity structure type solar evaporation unit;

[0065] 21- header tank, 22- micro-cavity structure solar vacuum tube, 23- front support, 24- rear support;

[0066] 211- header tank body, 212- blocking plate, 213- concentrated liquid discharge pipe, 214- connecting port;

[0067] 231- header tank support groove, 232- angle steel inclined leg, 233- front support, 234- concentrated liquid discharge pipe orientation adjustment notch;

[0068] 3- phase change condensation heat recovery device;

[0069] 31- steam passage, 32- air duct, 33- phase change-condensation temperature control cavity, 34- fresh water collection cavity;

[0070] 311- steam nozzle;

[0071] 4- fresh water collection bottle;

[0072] Ⅱ- solar main and cover integrated drying system

[0073] 5- wet heat recovery device;

[0074] 51- dehumidification and dust removal screen, 52- air collection port, 53- preheating air passage, 54- wet heat air passage;

[0075] 6- dry heat air conveying and adjusting fan unit;

[0076] 7- solar main and cover integrated drying chamber;

[0077] 71- double-layer light-transmitting tempered glass, 72- material tray slide rail support;

[0078] 8- wet heat air drainage and adjusting fan unit;

[0079] 9- square air duct;

[0080] 10- wet heat air pressurizing and adjusting fan;

[0081] Ⅲ- valley electricity auxiliary solar salt extraction and desalination water system

[0082] 111- concentrated liquid treatment unit, 112- fresh water collection unit;

[0083] Ⅳ- control system. DETAILED DESCRIPTION

[0084] The application will be further described below in conjunction with the drawings and examples. It can be understood that the specific examples described herein are only used to explain the related application, and are not a limitation on the application. In addition, it should be noted that only the parts related to the application are shown in the drawings for ease of description.

[0085] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0086] As shown in the drawings, the present embodiment provides a solar-powered desalination-drying-salt extraction integrated system, which is composed of a solar vacuum tube desalination system, a solar main and auxiliary drying system II, a valley power assisted solar salt extraction-desalination system III, and a control system. Figure 1

[0087] I: The structural features, functions and assembly methods of each system are described as follows:

[0088] (1) Micro-porous structure type solar vacuum tube 22 desalination system I

[0089] The micro-porous structure type solar vacuum tube 22 desalination system I is composed of a liquid level control unit 1, a micro-porous structure type solar evaporation unit 2, a phase change condensing heat recovery device 3, and a fresh water collection bottle 4 in series.

[0090] 1) Liquid level control unit 1: as shown in Figure 1 and 2 , the liquid level control unit 1 is composed of a water storage tank 11, a liquid level sensor 12, a water replenishment device, a liquid level control communication pipeline 13, and a support. The front-to-back direction of the water storage tank 11 is a trapezoidal long slot shape, the wide structure can reduce the start-stop frequency of the water replenishment pump, and the narrow structure can reduce the total weight of the water storage tank 11. The front-to-back direction length of the water storage tank 11 is comparable to the length of the header 21 to help reduce the water replenishment frequency, and the normal water storage capacity is comparable to the water storage capacity of the solar evaporation unit group. The liquid level of the water storage tank 11 is controlled by the liquid level sensor 12 and the water replenishment device, and then the liquid level in the micro-porous structure type solar vacuum tube 22 is adjusted to the theoretical interval through the liquid level control communication pipeline 13. The theoretical liquid level is between the lowest liquid level line and the highest liquid level line, which can not only maintain the driving force of the high-temperature steam outflow as needed, but also prevent the salt from overflowing through the steam outflow port and causing fresh water pollution.

[0091] 2) Micro-porous structure type solar evaporation unit 2: as shown in Figure 3 ​The header 21, the micro-hole structure type solar vacuum tube, the front support 23 and the rear support 24 are connected, and the header 21 is connected below the micro-hole structure type solar vacuum tube 22 and communicates with the micro-hole structure type solar vacuum tube 22. The micro-hole structure type solar vacuum tube 22, the front support 23 and the rear support 24 correspond to each other, the front support 23 is used for supporting the header 21, and the rear support 24 is used for supporting the micro-hole structure type solar vacuum tube 22. In the embodiment, the header 21 is provided with one, and the solar vacuum tube, the front support 23 and the rear support 24 are each provided with nine.

[0092] As Figure 4 The header 21 includes a header body 211 and two blocking plates 212 located on both sides of the header body 211, the two blocking plates 212 are connected with the header body 211 through flanges, one side of the blocking plate 212 is used for cleaning the dirt on the inner wall of the header 21, and the other side of the blocking plate 212 is provided with a connecting pipe for communicating with the pipeline. Nine solar vacuum tube connecting ports 214 and three concentrated liquid discharge pipes 213 are arranged on the header body 211. The concentrated liquid discharge pipes 213 are arranged at the middle positions of the front and rear directions of the header body 211 and are arranged at equal angles, and are respectively a concentrated liquid discharge pipe for winter (the solar elevation angle is the smallest in the whole year), a concentrated liquid discharge pipe for spring / autumn (the solar elevation angle is in the middle in the whole year) and a concentrated liquid discharge pipe for summer (the solar elevation angle is the largest in the whole year). The concentrated liquid discharge pipes 213 corresponding to different seasons are switched and used, the concentrated liquid is discharged to a concentrated liquid treatment tank after the header 21 stops producing water in a running day, and the other two concentrated liquid discharge pipes 213 are blocked by plugs during the idle period.

[0093] The micro-hole structure type solar vacuum tube is a metal-glass double-pass type vacuum tube, the inner surface of the inner metal tube is engraved with a micro-hole structure, which acts as a vaporization surface, and the outer glass tube can transmit solar radiation energy. The vacuum tube is sequentially provided with an inspection port, a pressurizing cavity, a vaporization cavity and a raw water through port from top to bottom. The inspection port is detachably sealed by a plug in a threaded form. The inner cavity of the vacuum tube is divided into two parts, the vaporization cavity and the pressurizing cavity, by a salt water liquid level. The pressurizing cavity is located above the vaporization cavity. The top of the pressurizing cavity is provided with a steam outflow pipe. The real-time volume of the pressurizing cavity is controlled by the liquid level of the water storage tank 11 and dynamically changes back and forth within a set range along with the evaporation time. The real-time volume is the cavity surrounded by the inner surface of the micro-hole structure type solar vacuum tube 22, the real-time liquid level line and the inner surface of the plug. The real-time liquid level line is located between the highest liquid level line and the lowest liquid level line. The vaporization surface of the vaporization cavity is provided with spiral type micro-hole structures and linear type micro-hole structures which are cross and uniformly cross in the axial direction by using a suitable means such as laser engraving, for improving the foaming core number of the vaporization surface and the steam bubble nucleation / detachment rate. The cross-sectional shape of the micro-hole structure can be one of eight types as shown in Figure 5 Figure 6 ​As shown, the cross-sectional shape and feature size of the micro-cavity structure can be optimized according to the solar radiation and meteorological conditions in different application areas within a proper range. In this embodiment, the depth (H) is 0.3 times the thickness (s), the opening width (D) is 0.3s, and the center distance (L) is 0.6s. The raw water passage can be manually inserted or pulled out of the connecting port 214 of the header 21, and the I-shaped sealing ring is used for sealing during connection.

[0094] As Figure 7 , the front support 23 is divided into a central position front support 23 and a non-central position front support 23. The central position front support 23 is one, corresponding to the middle micro-cavity structure type solar vacuum tube 22, including four angle steel inclined legs 232, four front supports 233 and one header support groove 231, and the bottom end of the angle steel inclined leg 232 is connected to the front support 233 by bolts. The header support groove 231 is circular arc-shaped and is welded to the top of the angle steel inclined leg 232, and the projection circle of the header support groove 231 is concentric with the circle of the cross section of the header 21, which can fully support the header 21. The header support groove 231 is provided with a concentrated liquid discharge direction adjusting slot at the center position, which cooperates with the rear support 24 to adjust the installation inclination angle of the micro-cavity structure type solar vacuum tube 22 according to the season. The non-central position front support 23 is eight, corresponding to the eight micro-cavity structure type solar vacuum tubes 22 on both sides of the middle position, and the other structures and sizes are the same as those of the central position front support 23, except that the concentrated liquid discharge tube direction adjusting slot 234 is not provided at the center position of the header support groove 231.

[0095] As Figure 1 and Figure 8 , the rear support 24 cooperates with the header 21 to support the micro-cavity structure type solar vacuum tube 22, which is composed of a rear support, a height adjusting rod, a rear support 24 connector and a fastening pad. Among them, the rear support mainly plays the role of support and installation inclination angle adjustment. In addition, winter front and rear lock, spring / autumn front and rear lock and summer front and rear lock are provided, which are used to connect the rear support 24 height adjusting rod and the rear support in different seasons. The rear support 24 height adjusting rod mainly plays the role of support and height adjustment, which is composed of an upper small rod and a lower large rod connected by a nut and a lock. The upper small rod and the lower large rod are both hollow square tubes, and the lower large rod is provided with winter high-low lock, spring / autumn high-low lock and summer high-low lock. The fastening pad is located between the rear support 24 connector and the outer surface of the micro-cavity structure type solar vacuum tube 22, and plays the role of tightening. The rear support 24 connector is used to connect the micro-cavity structure type solar vacuum tube 22 and the rear support 24 height adjusting rod, and is connected to the upper small rod of the height connecting rod by a screw-nut piece.

[0096] 3) Phase change condensing heat recovery device 3: The phase change condensing heat recovery device 3 is located on the right side of the heat recovery device 5, and the two are connected through connecting flanges. A flow straightening protective net is arranged between the connecting flanges to uniform the flow field and prevent foreign matter from mixing into the fan blades and causing failure. The phase change condensing heat recovery device 3 is located on the left side of the dry heat air conveying and adjusting fan group 6, and is connected by adding a flow straightening protective net between the two connecting flanges. The phase change condensing heat recovery device 3 is composed of steam channels 31, air ducts 32, phase change condensing-temperature control cavities and fresh water collection cavities 34. Two phase change condensing-temperature control cavities are symmetrically arranged on both sides of each steam channel 31, and a common heat exchange surface is arranged between each steam channel 31 and the phase change condensing-temperature control cavity adjacent thereto. The other heat exchange surface of each phase change condensing-temperature control cavity is shared with the adjacent air duct 32. In addition, the non-heat exchange surface shell is a heat preservation sealing surface.

[0097] The center plane of the phase change condensing heat recovery device 3 in the front-rear direction is the same plane as the center plane of the corresponding micro-cavity structure type solar vacuum tube 22 in the front-rear direction, and the steam channel 31 corresponds to the micro-cavity structure type solar vacuum tube 22 one by one. The inside of the steam channel 31 is a cuboid cavity. The front and rear sides of each steam channel 31 are heat exchange surfaces, the left and right directions are heat preservation sealing surfaces, the upper part is uniformly arranged with three steam nozzles 311 along the left-right direction, and the lower part is a rectangular full open port connected to the fresh water collection cavity 34. The steam channel 31 and the steam outflow pipe of the corresponding micro-cavity structure type solar vacuum tube 22 further include a steam nozzle 311, a steam flow sensor, an electric valve, a steam flow divider, an electric valve and a pressure sensor connected in turn by a high-temperature-resistant heat preservation steam pipe with a suitable pipe diameter. The pressure sensor and the electric valve-4 will link and control the steam pressure in the pressurizing cavity in the appropriate range at any time. When the steam pressure in the pressurizing cavity is less than the minimum value, the electric valve-4 will automatically adjust the opening degree. After the steam pressure in the pressurizing cavity gradually rises, the opening degree of the electric valve-4 will be dynamically adjusted. Under the linkage control of the steam flow sensor 1-3 and the electric valve 5-7, the steam flow divider can divide the high-temperature and high-pressure steam flowing out of the steam outflow pipe into three steam nozzles 311. The part of the steam nozzle 311 extending into the steam channel 31 is a triangular cavity with a thickness slightly smaller than the front-rear direction thickness of the steam channel 31, which can further diffuse the high-temperature and high-pressure steam to the left-right direction of the steam channel 31. The three steam nozzles 311 in parallel can ensure that the inflowing steam can fully cover the entire steam channel 31 in the left-right direction after diffusion. The two sides of the bottom surface of the steam channel 31 are micro chamfer surfaces arranged at a certain angle towards the front-rear direction common heat exchange surface, and a large number of small nozzles are uniformly and densely arranged at a certain interval in the left-right direction perpendicular to the chamfer surface, which can spray high-temperature steam to the common heat exchange surface for condensation and heat release. The heat is quickly transmitted to the phase change-condensing temperature control cavity 33, thereby realizing the dual purposes of condensation water production and phase change heat storage. The condensed fresh water will flow downward along the common heat exchange surface and be further cooled, and the low-temperature liquid fresh water will finally flow to the fresh water collection cavity 34, and finally flow into the fresh water collection bottle 4 after collection.

[0098] The adjacent air ducts 32 are symmetrically distributed on both sides of the steam channels 31 corresponding to them, and are also spaced apart from the steam channels 31. The inside of the air duct 32 is also a cuboid cavity, the length in the front-back direction is greater than the length of the steam channel 31 in the front-back direction, and the other direction size is the same as the steam channel 31. Each air duct 32 is completely open in the left-right direction, and is respectively a preheated dry air inlet and a dry hot air outlet. The front-back direction is a common heat exchange surface (except for the wall surface of the two most side air ducts 32), and the upper and lower surfaces are heat-insulating sealing surfaces. When the preheated dry air flows out of the outlet of the wet heat recovery device 5 and flows into the air duct 32, it is heated to a suitable temperature by the latent heat stored in the phase change condensation-temperature control cavity, and under the transportation and regulation of the dry hot air conveying and regulating fan group 6, it flows through the solar main-body integrated drying chamber 7 in a certain proportion in the up-down direction and the front-back direction, realizing the function of completely removing the moisture in the fresh materials.

[0099] The phase change condensation-temperature control cavity is a cuboid cavity with inverted trapezoidal ribs arranged symmetrically in the front-back direction heat exchange surface, and the length in the front-back direction is slightly smaller than the length of the air duct 32 in the front-back direction, and the length in the other direction is the same as that of the steam channel 31. The center of the upper wall surface of each phase change condensation-temperature control cavity is provided with a phase change material filling port for injecting high-temperature liquid phase change heat storage material into the phase change condensation-temperature control cavity, and a sealing cover is used for sealing after the phase change heat storage material is filled. The front-back direction is a common heat exchange surface, and other positions are heat-insulating sealing surfaces. The phase change condensation-temperature control cavity simultaneously realizes the functions of condensing water from high-temperature steam, heating "preheated dry air" on demand, and heat storage, scientifically coupling the solar desalination water and the solar drying process.

[0100] The fresh water collection cavity 34 is a semi-circular table type cavity with a large front and a small back, and is fixedly connected to the bottom surface of the phase change condensation-temperature control cavity, serving as the arc-shaped bottom surface of the phase change condensation heat recovery device 3, which is a heat-insulating sealing surface. The cavity is in communication with all steam channels 31, has a 3° inclination from back to front, and can realize the purpose of collecting fresh water and sending it into the fresh water collection bottle 4. The center of the lower arc surface of the front end of the fresh water collection cavity 34 is provided with a connecting pipe with an internal threaded port for connecting the fresh water collection bottle 4, and a ball valve is installed at the connecting pipe for cutting off the flow of fresh water when the fresh water collection bottle 4 is replaced. The four corners of the horizontal bottom surface (except for the arc-shaped bottom surface) of the phase change condensation heat recovery device 3 are provided with support connecting pieces, which can be connected to supports to support the phase change condensation heat recovery device 3.

[0101] The fresh water collection bottle 4 is a specially designed bottle, and the upper opening is an external threaded interface connected to the internal threaded port of the fresh water collection cavity in a threaded connection. In order to make the fresh water in the fresh water collection cavity flow smoothly into the fresh water collection bottle 4, a large air communication port-2 with a valve is specially provided on the side of the fresh water collection bottle 4.

[0102] (2) Solar energy main body integrated drying system II

[0103] As Figure 1 , the solar energy main body integrated drying system II is composed of, in sequence, a wet heat recovery device 5, a phase change condensation heat recovery device 3, a dry hot air conveying and adjusting fan set 6, a solar energy main body integrated drying chamber 7, a wet hot air drainage and adjusting fan set 8, a square air duct 9, and a wet hot air pressurizing and adjusting fan 10 connected through connecting flanges (rectifying protection nets are arranged between the connecting flanges), and further includes a support set.

[0104] 1) Wet heat recovery device 5: The wet heat recovery device 5 is located on the left side of the phase change condensation heat recovery device 3 and is connected through a connecting flange. The wet heat recovery device 5 is located above the wet hot air pressurizing and adjusting fan 10 and is connected through the addition of a rectifying protection net between the two connecting flanges. As Figure 10 , the wet heat recovery device 5 is composed of a dehumidifying and dust filtering net 51, a wind collecting port 52, ten preheating air passages 53, and nine wet hot air passages 54, among which the five middle wet hot air passages 54 are upwardly-inflow wet hot air passages 54, and the four wet hot air passages 54 on both sides are downwardly-outflow wet hot air passages 54.

[0105] The dehumidifying and dust filtering net 51 is located at the leftmost side of the wet heat recovery device 5 and is detachably installed at the entrance of the wind collecting port 52 by using buckles, mainly playing a role of filtering out moisture and aerosol particles in dry cold air to ensure that clean dry cold air flows into the preheating air passages 53.

[0106] The wind collecting port 52 plays a role of collecting clean dry cold air.

[0107] The two preheating air passages 53 at the most two sides in the front-rear direction are long rectangular cavities fully opened in the left-right direction, the middle-biased surface is a common heat exchange surface between the preheating air passages 53 and the wet hot air passages 54, and the other surfaces are heat preservation sealing surfaces. The eight preheating air passages 53 between the two preheating air passages 53 at the most two sides in the front-rear direction are kiln-shaped cavities fully opened in the left-right direction, the front plane, the rear plane, and the upper arc surface are common heat exchange surfaces with the wet hot air passages 54, and the lower plane is a heat preservation sealing surface. The preheating air passages 53 preheat the clean dry cold air flowing from the wind collecting port 52 by using the heat carried by the wet hot air to obtain preheated dry air, and further send the preheated dry air into the inlet of the air duct 32 of the phase change condensation heat recovery device 3, and heat the preheated dry air into dry hot air with an ideal temperature in the air duct 32 of the phase change condensation heat recovery device 3.

[0108] The wet hot air passage 54 is a cavity with intercommunication provided with flow-equalizing baffles, shares the heat exchange surface with the preheating air passage 53, and the wet hot air inlet and the wet hot air outlet are both full-open rectangular ports. Under the regulation of the inlet flow-equalizing baffles, the wet hot air flows into the wet hot air passage 54 evenly upward through the middle five wet hot air inlets, and under the regulation of the outlet flow-equalizing baffles, the wet hot air flows out of the wet hot air outlet evenly downward through the two side four wet hot air passages 54, and the wet cold air flowing out of the wet hot air outlet is finally discharged into the environment. The wet hot air passage 54 is the flow channel of the wet hot air, and in the process of flowing, the wet hot air will transfer the heat it carries to the clean dry cold air flowing in from the air collecting port 52 through the heat exchange surface shared with the preheating air passage 53, and the preheated dry air is discharged at the outlet of the preheating air passage 53.

[0109] 2) Wet hot air pressurizing and adjusting fan 10: The upper part of the wet hot air pressurizing and adjusting fan 10 is connected with the lower part of the wet heat recovery device 5 by adding a flow-protecting net between the two connecting flanges. The lower part of the wet hot air pressurizing and adjusting fan 10 is connected with the square air duct 9 by adding a flow-protecting net between the two connecting flanges. The wet hot air pressurizing and adjusting fan 10 belongs to an independent six-blade frequency-modulated fan with connecting flanges on both sides of the upper and lower directions, and heat-preservation sealing enclosure structures around the front and back directions and the left and right directions. The fan speed is controlled by mutual feedback of the temperature sensor at the lower end, and the higher the wet hot air temperature, the smaller the fan speed, so as to ensure that the heat carried by the wet hot air can be fully recovered. When the wet hot air temperature decreases, the fan speed will increase, providing sufficient heat for the dry cold air preheating process.

[0110] 3) Phase change condensation heat recovery device 3: same as above.

[0111] 4) Dry hot air conveying and adjusting fan group 6: mainly plays the role of conveying dry hot air to the inside of the drying chamber and adjusting the dry hot air flow in different areas. For example, Figure 1 and 11, the connecting flange on the left side of the dry air conveying and adjusting fan group is connected with the connecting flange on the right side of the phase change condensation heat recovery device 3 through bolts, and a rectifying protection net is arranged between the two connecting flanges, and the rectifying protection net comprises a net body, a net frame and a sealing integrated pad, and the sealing integrated pad plays the sealing and rectifying roles. The connecting flange on the right side of the dry air conveying and adjusting fan group is connected with the connecting flange at the dry hot air inlet of the solar main body integrated drying chamber 7 through bolts, and a rectifying protection net is also arranged between the two connecting flanges. The dry hot air conveying and adjusting fan group 6 is surrounded by a surrounding structure with heat preservation and sealing functions, and two layers of six-blade frequency-regulating fans with eight in total are arranged in the up-down direction inside the dry hot air conveying and adjusting fan group 6, and the six-blade frequency-regulating fans are fixedly connected to the fan support structure, and reinforcing keels fixedly connected with the surrounding structure are uniformly arranged between the fans, so that the stability is improved. The rotating speeds of the six-blade frequency-regulating fans are mutually fed back and controlled by the temperature sensors arranged at the material trays of the solar main body integrated drying chamber 7 and located downstream of the six-blade frequency-regulating fans. When the dry hot air temperature is higher than the set value (the phase change temperature of the phase change heat storage material), the rotating speeds of the fans are automatically reduced, so that the heat carried by the dry hot air can be fully utilized. When the dry hot air temperature is lower than the set value, the rotating speeds of the fans are automatically increased, so that sufficient heat is provided for the fresh material drying process.

[0112] 5) The solar main body integrated drying chamber 7 actively utilizes the dry hot air sent from the dry hot air inlet by the dry hot air conveying and adjusting fan group to dry specific fresh materials, and passively utilizes the solar radiation energy from the double-layer light-transmitting glass to assist in drying the specific fresh materials. Figure 1 and 12 The left side of the solar main body integrated drying chamber 7 is a dry hot air inlet with a connecting flange. The right side and the rear side of the solar main body integrated drying chamber 7 are heat preservation and sealing surrounding structures. The front side of the solar main body integrated drying chamber 7 is provided with a material tray pulling and sealing opening, so as to facilitate replacement of the materials in the material trays and maintenance and repair. The upper part of the solar main body integrated drying chamber 7 is provided with double-layer light-transmitting tempered glass 71 fixedly supported by light-transmitting surface support members and installed towards the south and inclined according to the local latitude, so as to passively utilize solar energy to assist in drying fresh materials. The lower part of the solar main body integrated drying chamber 7 is provided with a connecting flange and connected with the upper flange of the wet hot air guiding and adjusting fan group 8 through bolts. The dry hot air flows into the drying chamber through the dry hot air inlet under the joint control of the dry hot air conveying and adjusting fan group and the wet hot air guiding and adjusting fan group 8, and then flows out through the wet hot air outlet. The cavity surrounded by the upper double-layer light-transmitting glass, the lower wet hot air outlet, the left dry hot air inlet, the front material tray pulling and sealing opening and the right and rear heat preservation and sealing surrounding structures is a drying chamber for drying specific fresh materials. Six layers of material tray slide rail support groups are fixedly arranged in the drying chamber, and each material tray slide rail support group comprises five material tray slide rail supports 72 arranged at equal intervals and used for supporting the material trays and acting as the bottom roller slide rails of the material trays.

[0113] As Figure 1 , 12 and 13, the material tray is a detachable component of the solar body-integrated drying chamber 7. The bottom of the material tray is provided with five roller groups corresponding to the material tray slide rail supports 72. Each roller group includes 26 carbon fiber material rollers arranged in a linear array at equal intervals, realizing the rolling and pulling separation and assembly between the material tray and the solar body-integrated drying chamber 7, to facilitate the taking and placing of materials. The material tray shelf is a stainless steel sheet with dense airflow through-holes, which is divided into 16 independent storage areas by left-right five and front-back four storage area partitions, which can improve the uniformity and stability of material distribution. The front side of the material tray is a sealing baffle with sealing and heat preservation functions, and is provided with two pulling handles for easy manual pulling operation.

[0114] 6) Wet hot air drainage and regulation fan set 8: as Figure 1 and 14 , the wet hot air drainage and regulation fan set 8 is provided with a connecting flange at the upper end, which is connected to the lower flange of the solar body-integrated drying chamber 7 through bolts. Below the connecting flange of the wet hot air drainage and regulation fan set 8, there are upper, middle and lower three parts. Four six-blade frequency modulation fans are installed in the fan positioning and supporting structure in the hexahedral large cavity of the upper part, mainly playing the role of draining wet hot air and regulating the flow direction of the air in the drying chamber (using temperature and humidity sensors arranged at the outlet of the wet hot air to link and control), to ensure uniform drying and improve drying quality. The middle part is a four-prism-shaped cavity that can converge wet hot air to a wet hot air convergence cavity with a smaller cross-sectional area, which not only reduces the connection difficulty and material cost of the square air duct 9, but also greatly reduces the space required for installing the square air duct 9. The lower side is a transition section connected to the square air duct 9. The filter screen positioning frame for installing the wet hot air filter screen is arranged at the inlet of this section. Among them, the wet hot air filter screen can remove impurities carried out by the wet hot air from the drying chamber. The lowermost side of this section is a connecting flange for connecting the square air duct 9.

[0115] 7) Support group: as Figure 1 , 9 and 12, support connecting pieces are arranged at the bottom corners of the phase change condensation heat recovery device 3 and the wet hot air drainage and regulation fan set 8, which are used for detachable connection of corresponding supports to play a stable supporting role.

[0116] (3) Valley electricity assisted solar salt extraction and desalination water system III

[0117] As Figure 15, the valley electricity assisted solar salt-demineralized water system III is composed of micro cavity structure type solar evaporation unit 2, concentrated liquid treatment unit 111 and fresh water collection unit 112 in series. Among them, the concentrated liquid discharge pipeline of header 21 is connected with micro cavity structure type solar vacuum tube 22 demineralized water unit and concentrated liquid treatment unit 111, which can make full use of the sensible heat carried by the concentrated liquid produced by micro cavity structure type solar vacuum tube 22 demineralized water link, and use valley electricity and passive solar distillation structure to continuously evaporate water in concentrated liquid in time period, which can not only further produce fresh water, but also deeply extract salt containing by-products with certain economic value. The water collecting arc plate and the water guide pipe behind it connect the concentrated liquid treatment unit 111 and the fresh water collection unit 112.

[0118] 1) micro cavity structure type solar evaporation unit 2: same as above.

[0119] 2) concentrated liquid treatment unit 111: including concentrated liquid discharge pipeline, concentrated liquid treatment pool and passive solar distillation structure.

[0120] One end of the concentrated liquid discharge pipeline is connected with the concentrated liquid discharge pipe 213 of the header 21, and is connected with the electric valve-2 and the concentrated liquid discharge pump in turn, and the other end of the concentrated liquid discharge pipeline is connected with the concentrated liquid treatment pool. The discharge process of concentrated liquid is controlled by the linkage of electric valve-2, electric valve-3 and concentrated liquid discharge pump. When the micro cavity structure type solar evaporation unit 2 ends, the electric valve-3 is automatically closed to cut off the raw water supply channel, and then the electric valve-2 and the concentrated liquid discharge pump are automatically opened in turn. When the concentrated liquid is completely discharged, the concentrated liquid discharge pump and the electric valve-2 are closed in turn, and the electric valve-3 is automatically opened to supply water, so as to realize the purpose of completely discharging concentrated liquid.

[0121] The concentrated liquid treatment pool is a subterranean pool (the front-to-back direction projection is a trapezoid with a wide top and a narrow bottom), and the pool bottom and the four walls are all made of a superposition structure of concrete and thermal insulation layer (to prevent heat loss to the maximum extent). A waterproof wall-mounted electric heating plate is installed on each wall below the raw water liquid surface to heat the concentrated liquid using 220V alternating valley electricity. A stirring impeller is symmetrically installed on both sides of the central plane perpendicular to the left-to-right direction of the pool, which is driven to rotate by a stirring motor and supported by a positioning bearing embedded in the front-to-back direction wall (a small section of the impeller tip needs to protrude out of the concentrated liquid surface). The stirring impeller is a forward stirring impeller and a reverse stirring impeller from left to right, which is used to stir the concentrated liquid in the opposite direction to ensure that the water vapor inside the concentrated liquid is fully discharged, thereby improving the efficiency of the auxiliary desalination water. The valley electricity auxiliary distillation concentrated liquid process is controlled by the wall-mounted electric heating plate, the stirring motor set, and the clock linkage. The specific control process is as follows: during the night valley electricity price period: when the wall-mounted electric heating plate is powered on and heated, the stirring motor set is started after a 10-minute delay. When the wall-mounted electric heating plate is powered off, the stirring motor set is turned off after a 10-minute delay; during the night non-valley electricity price period: the wall-mounted electric heating plate stops running. After sunrise during the day, the stirring motor set is started once every 30 minutes, and each stirring lasts for 5 minutes. During the non-valley electricity price period after sunset during the day, the stirring motor set stops running.

[0122] The passive solar distillation structure includes a support and thermal insulation enclosure structure extending from the concentrated liquid treatment pool, a double-layer light-transmitting tempered glass 71, a condensing fan set, a hydraulic lifting mechanism, a position limiter, and a water collecting arc plate. The support and thermal insulation enclosure structure is a four-wall enclosure structure constructed around the concentrated liquid treatment pool, which has a convex structure with the highest point lower than the lowest point of the header 21 and the left low and right high characteristics, which can give the double-layer light-transmitting tempered glass 71 a certain installation inclination. This not only improves the utilization rate of solar energy, but also promotes the rapid flow of condensed fresh water at the inner surface of the double-layer light-transmitting tempered glass 71 to the water collecting arc plate. The right end of the double-layer light-transmitting tempered glass 71 is connected to the upper surface of the right side enclosure wall of the support and thermal insulation enclosure structure through a rotating shaft, which can open and close the double-layer light-transmitting tempered glass 71 as needed. When removing the salt-containing by-products, the hydraulic lifting mechanism (symmetrically arranged in the front-to-back direction) is used to lift the double-layer light-transmitting tempered glass 71 from the left side manually. After the removal is completed, the hydraulic lifting mechanism is used to lower the double-layer light-transmitting tempered glass 71 from the left side again using manual control. The position limiter and the hydraulic lifting mechanism are linked to control the lifting / dropping process of the double-layer light-transmitting tempered glass 71. When the left end of the double-layer light-transmitting tempered glass 71 contacts the limit switch of the position limiter, an immediate contact signal is fed back to the control center, and the control center sends a command to immediately close the hydraulic lifting mechanism. The long-strip-shaped condensing fan set in the front-to-back direction is installed on the outer surface of the double-layer light-transmitting tempered glass 71 along the left-to-right direction at equal intervals, and is linked to the stirring motor to be started and stopped synchronously, which is used to accelerate the condensation of water vapor at the inner surface of the double-layer light-transmitting tempered glass 71, so that the condensed fresh water can flow quickly to the water collecting arc plate.

[0123] 2) Fresh water collecting unit 112: including fresh water collecting pool and fresh water supply unit.

[0124] The fresh water collecting pool is used to store the fresh water collected by the water collecting arc plate, is a subterranean cuboid water storage pool, and is communicated with the passive solar distillation structure through a water guide pipe. The water guide pipe includes a vertical part and an inclined part. The vertical part of the water guide pipe penetrates the top cover of the fresh water collecting pool and is fixedly connected with the top cover. The lower outlet of the vertical part of the water guide pipe is 2-3 cm higher than the liquid level of the fresh water. The lower end of the inclined part of the water guide pipe is flexibly connected with the upper end of the vertical part. The inclination angle of the inclined part can be adjusted according to the actual situation. The upper end of the inclined part is communicated with the water outlet in the passive solar distillation structure, which is located at the lowest center position in the front-rear direction of the water collecting arc plate. An atmospheric communication port-1 is also arranged at the top cover of the fresh water collecting pool. The atmospheric communication port-1 mainly plays a role of communicating with the atmosphere to balance the pressure, thereby ensuring that the fresh water at the water collecting arc plate can continuously and smoothly flow into the fresh water collecting pool. The lower end of the atmospheric communication port-1 penetrates the top cover of the fresh water collecting pool and is fixedly connected. The upper end of the atmospheric communication port-1 is a semicircular circular pipe with the outlet downward, which can prevent dust, rainwater and other sundries from falling into the vent pipe to cause blockage and avoid pollution of the fresh water.

[0125] The fresh water supply unit includes a fresh water pump, a water conveying pipeline and an electric valve-1. The fresh water pump is a submersible drinking water pump driven by 220V alternating current and submerged to the bottom of the fresh water collecting pool. The electric valve-1 is a manually controlled electric valve installed in the water conveying pipeline above the ground. The electric valve-1 is linked with the fresh water pump to control the fresh water supply process. When the user needs to take fresh water, the electric valve-1 is opened by manually pressing the start key at the control panel of the electric valve-1. At the same time, the start signal is fed back to the control center. After the control center sends the start instruction, the fresh water pump is started to output fresh water from the outlet of the fresh water supply pipe. The water conveying pipeline includes a vertical pipe and a fresh water supply pipe. The vertical pipe is connected with the fresh water pump, the electric valve-1 and the fresh water supply pipe. The fresh water supply pipe is a semicircular circular pipe with the outlet downward, which not only plays a role of taking low-temperature liquid fresh water, but also can prevent dust, rainwater and other sundries from falling into the fresh water supply pipe to cause blockage and avoid pollution of the fresh water.

[0126] (4) Control system IV

[0127] As shown in Figure 1 , the control system is composed of a control center, a signal transmission line and terminal equipment.

[0128] The control center is arranged in a control room or a control cabinet with protection functions such as waterproof, dustproof and sunproof, and plays a role of data monitoring, data storage, signal mutual feedback and instruction output.

[0129] The signal transmission line is used to communicate the control center, the sensor and the power equipment, and plays a role of signal transmission.

[0130] The terminal device comprises a sensor, an electric valve and a power device. The sensor comprises a pressure sensor, a temperature sensor, a humidity sensor, a flow sensor and a liquid level sensor 12, etc., for collecting pressure, temperature, humidity, flow and liquid level data in real time. The electric valve is used to adjust the on-off or opening degree of the pipeline. The power device comprises a pump, a fan and a wall-mounted electric heating plate.

[0131] Two: efficient desalination, drying and salt extraction integrated method assisted by off-peak electricity and solar energy

[0132] (1) System integration method (coupling integration method): solar desalination, solar drying and off-peak electricity assisted solar deep salt extraction-desalination are closely coupled to realize the gradient and diversified coupling utilization of solar energy. Among them, the phase change condensation heat recovery device 3 couples the micro-cavity structure type solar vacuum tube 22 desalination and the solar main and body integrated drying link, and the micro-cavity structure type solar evaporation unit 2 (the concentrated liquid discharge pipe 213 of the header 21) couples the micro-cavity structure type solar vacuum tube 22 desalination and the off-peak electricity assisted solar deep salt extraction-desalination link, which not only greatly improves the solar energy utilization rate, water production, operation reliability and system economy, but also realizes the diversification of functions, and has strong universal applicability.

[0133] (2) Pool boiling vaporization performance enhancement method: a multi-effect enhancement method of hydrophobic modification of vaporization surface and construction of micro-cavity structure is adopted to construct a vaporization surface of the inner wall of the solar vacuum tube with the best contact angle (hydrophobicization of the inner surface of the vacuum tube), the best shape of the micro-cavity structure (such as laser engraving means to construct the micro-cavity structure) and the optimal combination of its characteristic size, which increases the number of foaming cores of the vaporization surface of the micro-cavity structure type solar vacuum tube 22 and the vapor bubble nucleation / detachment rate, and improves the heat transfer coefficient, effectively solving the problem of low pool boiling vaporization intensity of the smooth type solar vacuum tube distiller.

[0134] (3) Dry hot air temperature regulation method (waste heat reuse and phase change condensation heat recovery temperature control method): the dry cold air is preheated by the wet hot air discharged from the solar main and body integrated drying chamber 7 to preliminarily improve the solar energy utilization rate and the temperature of the preheated dry air entering the inlet of the air duct 32 of the phase change condensation heat recovery device 3. Further, the low-temperature phase change heat storage material is used as the condensation medium of the solar desalination link, and combined with the innovative design of the passive solar drying box structure, the purpose of constant temperature heating of the preheated dry air is achieved, and the drying quality and efficiency of the solar drying link are improved.

[0135] (4) Salt-containing byproduct separation method (valley electricity assisted solar distillation separation method): Based on the sensible heat carried by the concentrated liquid produced by the micro-cavity structure type solar vacuum tube 22, the concentrated liquid is heated by the wall-attached electric heating plate during the night valley electricity price period, and under the stirring action of the stirring impeller, more than 85% of the water in the concentrated liquid is quickly and efficiently removed to obtain a preliminary concentrated liquid. During the next day, the preliminary concentrated liquid is further heated by passive solar distillation method, and under the stirring action of the stirring impeller, the remaining water in the concentrated liquid is quickly and efficiently removed to obtain anhydrous salt-containing byproduct. The above method can continuously and efficiently evaporate the water in the concentrated liquid, not only can further collect a large amount of fresh water, but also can extract salt-containing byproducts with certain economic value, which can improve the utilization rate of solar energy, and also improve the economic efficiency and practical value of the system.

[0136] Three: Energy and mass transfer principle in high-efficiency desalination-drying-salt extraction integrated system based on solar energy supply

[0137] As shown in Figure 16 , the energy input in the high-efficiency desalination-drying-salt extraction integrated system based on solar energy supply includes solar radiation energy and valley electricity, in addition to the conventional driving power (not shown in Figure 16 ) for driving the operation of power equipment such as pumps and fans. The input energy is used to drive the complete separation of water in raw water and salt-containing byproducts, and also to remove the water in fresh materials, finally achieving the purpose of producing fresh water, extracting salt-containing byproducts and producing dry materials.

[0138] As shown in Figure 16 , the mass input in the high-efficiency desalination-drying-salt extraction integrated system based on solar energy supply includes raw water, dry cold air and fresh materials, and the mass output includes fresh water, salt-containing byproducts, dry materials and wet cold air. Among them, fresh water, salt-containing byproducts and dry materials are effective products required by users.

[0139] The solar energy-based desalination-water-drying-salt extraction integrated system and method of the present embodiment first constructs a micro-porous cavity structure on the evaporation surface of the solar vacuum tube, which can increase the number of evaporation surface foaming cores and improve the heat exchange coefficient. The contact angle, the shape of the micro-porous cavity structure and its characteristic size are the decisive factors for the nucleation / detachment rate of the evaporation surface vapor bubble. Therefore, by using the multi-effect enhancement method of hydrophobic modification of the evaporation surface combined with the construction of the micro-porous cavity structure, the evaporation surface with the optimal combination of the contact angle, the shape of the micro-porous cavity structure and its characteristic size is constructed on the inner surface of the solar vacuum tube, which can effectively solve the problem of low pool boiling evaporation intensity of the solar vacuum tube. Secondly, the condensation heat is recovered and used in the fresh material drying link. According to the optimal dry hot air temperature required by the specific fresh material, the low-temperature phase change heat storage material matched with the condensing medium is used to heat the "preheated dry air" at a constant temperature, and combined with the innovative structural design of the solar primary and secondary integrated drying chamber, the ideal fresh material drying quality and drying efficiency can be ensured. In addition, the use of wet hot air discharged from the drying chamber to preheat dry cold air can further improve the utilization rate of solar energy. Finally, the concentrated liquid produced in the daytime desalination water process is discharged to a specially designed concentrated liquid treatment pool. Based on the sensible heat carried by the concentrated liquid, the valley electricity heating method is used at night, and the passive solar distillation method (top light-transmitting tempered glass and condensing fan set) is used the next day, which can continuously and efficiently evaporate the water in the concentrated liquid, not only can extract the salt-containing byproduct with certain economic value, but also can further improve the utilization rate of solar energy, and has high system economy and practical value. Therefore, the system has high solar energy utilization rate, diversified functions, strong practicality, large unit and total water production, high drying quality and drying efficiency, good reliability and excellent economy, and has a wide application prospect.

[0140] Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with each other to form a technical solution with similar functions disclosed in the present application (but not limited to).

Claims

1. A solar energy based integrated system for desalination, water drying and salt extraction, characterized in that, The system comprises a solar vacuum tube water desalination system, a solar main-body integrated drying system, a valley electricity assisted solar salt extraction and water desalination system and a control system. The solar vacuum tube water desalination system is connected with the valley electricity assisted solar salt extraction and water desalination system, and transports concentrated liquid to the system, so that the concentrated liquid is separated into low-temperature liquid fresh water and salt-containing by-products in the valley electricity assisted solar salt extraction and water desalination system. The solar vacuum tube water desalination system is connected with the solar main-body integrated drying system, and transports dry hot air to the system, so that the dry hot air dries materials in the solar main-body integrated drying system. The control system controls the operation of the whole system. The solar vacuum tube water desalination system is a micro-porous structure type solar vacuum tube water desalination system, which is sequentially composed of a liquid level control unit, a micro-porous structure type solar evaporation unit, a phase change condensation heat recovery device and a fresh water collection bottle. The liquid level control unit comprises a water storage pool supported by a support; a liquid level sensor is arranged in the water storage pool, and the water storage pool is supplied with water through a liquid level control communication pipeline. Alternatively, the micro-porous structure type solar evaporation unit comprises a header and a plurality of micro-porous structure type solar vacuum tubes, and the header is communicated with the lower part of each micro-porous structure type solar vacuum tube. Alternatively, the phase change condensation heat recovery device comprises a steam passage corresponding to each micro-porous structure type solar vacuum tube, and the steam passage is flanked by air ducts, and the air passing through the air ducts can enter the solar main-body integrated drying chamber under the transportation and regulation of a dry hot air transportation and regulation fan set; a phase change-condensation temperature control cavity is further arranged between the air ducts and the steam passage, the lower part of the phase change-condensation temperature control cavity is communicated with a fresh water collection cavity, and the lower part of the fresh water collection cavity is communicated with a fresh water collection bottle. The header comprises a header body and blocking plates connected to the two sides of the header body, the header body is provided with three concentrated liquid discharge pipes and connection ports corresponding to the micro-porous structure type solar vacuum tubes, and the concentrated liquid discharge pipes are arranged at the middle positions of the header body in the front-rear direction and are arranged at equal arc.

2. The solar energy based integrated desalination-watering- salt extraction system as claimed in claim 1, wherein, The header is supported by front supports, the micro-porous structure type solar vacuum tubes are supported by rear supports, the front supports are provided with a plurality of header support grooves, the lower part of each header support groove is connected with an angle steel inclined support leg, the lower part of the angle steel inclined support leg is connected with a front support base, and a concentrated liquid discharge pipe orientation adjustment slot is arranged in the header support groove of the middle front support; the height of the rear support is adjustable. Alternatively, a steam nozzle is arranged between the steam passage and the steam outflow pipe of the corresponding micro-porous structure type solar vacuum tube. Alternatively, the fresh water collection cavity is a semicircular table type with a large front part and a small rear part, and is fixedly connected to the bottom surface of the phase change condensation-temperature control cavity, the cavity is communicated with all the steam passages, and has a certain inclination from the rear to the front.

3. The solar energy based integrated desalination-watering- salt extraction system as claimed in claim 1, wherein, The solar main-body integrated drying system is sequentially composed of a wet heat recovery device, a phase change condensation heat recovery device, a dry hot air conveying and adjusting fan unit, a solar main-body integrated drying chamber, a wet hot air drainage and adjusting fan unit, a square air duct, a wet hot air pressurizing and adjusting fan through connecting flanges, and further includes a support group. The phase change condensation heat recovery device is communicated with the micro-porous cavity structure type solar evaporation unit.

4. The solar energy based integrated desalination-watering- salt extraction system as claimed in claim 3, wherein, The wet heat recovery device is located above the wet hot air pressurizing and adjusting fan and includes a dehumidifying and dust filtering net, a wind collecting port, a plurality of preheating air channels, and a wet hot air channel. Alternatively, the solar main-body integrated drying chamber is provided with a double-layer light-transmitting toughened glass supported by a light-transmitting surface support at the upper portion and tilted towards the south according to the local latitude, and is connected with the wet hot air drainage and adjusting fan unit at the lower portion.

5. The solar powered integrated desalination-watering-salting system of claim 1, wherein, The valley electricity assisted solar salt extraction and desalinated water system is sequentially composed of a micro-porous cavity structure type solar evaporation unit, a concentrated liquid treatment unit, and a fresh water collecting unit.

6. The solar powered integrated desalination-watering-evaporation system of claim 5, wherein, The concentrated liquid treatment unit includes a concentrated liquid discharge pipeline, a concentrated liquid treatment pool, and a passive solar distillation structure. The concentrated liquid treatment pool is an underground pool body and is internally provided with forward and reverse stirring impellers. The passive solar distillation structure includes a support and heat preservation enclosure structure extending outward from the concentrated liquid treatment pool, a double-layer light-transmitting toughened glass at the top, and a condensation fan unit above the double-layer light-transmitting toughened glass and supporting and controlling the lifting process of the double-layer light-transmitting toughened glass through a hydraulic lifting mechanism.

7. The solar powered integrated desalination-watering-salting system of claim 5, wherein, The fresh water collecting unit includes a fresh water collecting pool and a fresh water supply unit.

8. A method for desalination, water-drying and salt extraction by the integrated system according to any one of claims 1 to 7, characterized in that, The system integration method includes: System integration method: solar desalinated water, solar drying, and valley electricity assisted solar deep salt extraction and desalinated water are tightly coupled to realize gradient and diversified coupling utilization of solar energy. The method for enhancing pool boiling vaporization performance: a multi-effect enhancement method of hydrophobic modification of vaporization surface and construction of micro-cavity structure, which constructs the vaporization surface of the inner wall of solar vacuum tube with the optimal contact angle, the optimal micro-cavity structure shape and the optimal combination of characteristic size; The method for regulating dry hot air temperature: a method of regulating air volume by mutual feedback of inlet and outlet temperature of air duct of phase change condensation heat recovery device, which uses the wet hot air discharged from the solar main and secondary integrated drying chamber to preheat dry cold air, so as to preliminarily improve the solar utilization rate and the temperature of preheated dry air entering the inlet of air duct of phase change condensation heat recovery device; The method for separating salt-containing by-products: a multi-means time sequence separation method, which removes water in the concentrated liquid based on the sensible heat carried by the concentrated liquid produced by the micro-cavity structure type solar vacuum tube at night valley electricity price period, so as to obtain a preliminary concentrated liquid; the next day, the passive solar distillation method is further used to heat the preliminary concentrated liquid to remove the remaining water in the concentrated liquid, so as to obtain a water-free salt-containing by-product.

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