Cascade axial flow brackish water crystallization system and method of use

Abstract

The application discloses a kind of cascade axial flow salt crystallization system of brackish water and its using method, the system includes: photothermal salt collection module and finnill salt collection module are installed on support side by side, the salt outlet of photothermal salt collection module is connected by electromagnetic valve with the salt inlet of finnill salt collection module, the center line of photothermal salt collection module, electromagnetic valve and finnill salt collection module is coaxial, forms axial flow cascade body, first heat collection pipe is equipped with first spiral scraper mechanism and is pushed to second heat collection pipe with material, second heat collection pipe is equipped with second spiral scraper mechanism and is pushed to salt discharge port with material.By the cascade axial flow technical means of photothermal salt collection, finnill salt collection, brackish water is preheated with high efficiency, primary crystallization, secondary crystallization, and brackish water steam is condensed and recovered, realize the zero energy consumption of brackish water water-salt resource collection.Solve the problem of large energy consumption and low efficiency of existing brackish water evaporation crystallization.

Description

Technical Field

[0001] This invention belongs to the field of saline water crystallization treatment technology, specifically relating to a cascaded axial flow saline water crystallization system and a method for using the cascaded axial flow saline water crystallization system. Background Technology

[0002] Saltwater causes soil salinization and acidification, harming plant growth, reducing crop quality, and leading to environmental water pollution and ecological damage. my country's saltwater is mainly distributed in the arid northwest and eastern coastal areas, with its total volume far exceeding that of freshwater, indicating abundant saltwater resources with enormous development potential. Currently, some development and utilization have been implemented, such as solar evaporation, boiling, lake salt production, evaporation ponds, electrolysis, and ion exchange for producing salt, alkali, and chlorine from saltwater. Compared to other methods, evaporation, which uses industrial heating to promote evaporation, is energy-intensive and inefficient. However, natural solar radiation provides abundant heat through radiation, and related technologies such as concentrated solar power, selective solar membranes, vacuum solar power, and lens solar power are relatively mature. If these existing technologies can be effectively combined to innovate a natural force-driven solar power collection method utilizing solar radiation, and a novel salt collection system based on this natural force is developed, it will provide innovative theories and technologies for the resource utilization of saltwater.

[0003] Therefore, it is both necessary and urgent to study a cascaded axial flow saline water crystallization system. Summary of the Invention

[0004] The purpose of this invention is to provide a cascaded axial flow brine crystallization system and its usage method to solve the problems of high energy consumption and low efficiency in existing brine evaporation crystallization systems.

[0005] The technical solution adopted in this invention is a cascaded axial flow brine crystallization system, comprising a photothermal salt collection module and a Fresnel salt collection module fixedly mounted side-by-side on a support. The photothermal salt collection module includes a first heat collection tube and a reflector. The first heat collection tube is fixedly mounted above the support, and the reflector is fixedly mounted below the first heat collection tube, with the light focused by the reflector able to irradiate the first heat collection tube for heating. The first heat collection tube has an inner cavity for containing brine and an inlet, a salt outlet, and a steam outlet communicating with the inner cavity. The Fresnel salt collection module includes a second heat collection tube and a linear Fresnel convex lens. The second heat collection tube is fixedly mounted on the support, and the linear Fresnel convex lens is fixedly mounted above the second heat collection tube, with the light focused by the linear Fresnel convex lens able to irradiate the second heat collection tube for heating. The second heat collection tube has an inner cavity and an inlet and a outlet communicating with the inner cavity, with the outlet communicating with the inlet.

[0006] Preferably, an electromagnetic valve is installed on the pipe connecting the salt outlet and the salt inlet. The center lines of the solar thermal salt collection module, the electromagnetic valve, and the Fresnel salt collection module are coaxial, forming an axial flow cascade. A first spiral scraper mechanism is provided inside the first heat collection tube, which can push the material in the first heat collection tube to the second heat collection tube. A second spiral scraper mechanism is provided inside the second heat collection tube, which can push the material in the second heat collection tube to the salt outlet.

[0007] Preferably, the inlet of the first heat collector tube is located at the head end and is connected to the brine outlet of the heat exchanger through a first pipe. The heat exchanger is mounted on a bracket and is also provided with a brine inlet. A condensate outlet is provided at one end of the side wall of the heat exchanger near the brine inlet, and a steam inlet is provided at one end of the side wall of the heat exchanger near the brine outlet. The steam inlet is connected to the exhaust port of the first heat collector tube through a second pipe, and the condensate outlet is connected to a water collection pipe.

[0008] Preferably, the first heat collection tube is installed inside the first vacuum tube and extends out of the first vacuum tube with sealed ends. The inner wall of the first vacuum tube is provided with a unidirectional light coating layer and a heat insulation coating layer from the inside to the outside. The first heat collection tube is provided with a first upper flange and a first lower flange at both ends. The first spiral scraper mechanism includes a first drive motor with a first connecting hole and a photothermal salt collection auger fixedly connected to the first rotor inside it. The first rotor is a bushing structure. The photothermal salt collection auger is axially installed inside the first heat collection tube and maintains movable contact with the inner wall of the first heat collection tube. The photothermal salt collection auger is provided with a first discharge inner hole axially upward. One end of the first stator of the first drive motor is fixedly connected to the first upper flange, and the other end of the first stator of the first drive motor is fixedly connected to the flange of the first pipe. The first lower flange is fixedly connected to the input end of the solenoid valve.

[0009] Preferably, the aforementioned photothermal salt collecting auger includes a first helical blade with an L-shaped cross-section and a first fixed flange fixedly installed at its head end. The first fixed flange is fixedly connected to the first rotor. A first heat insulation layer is provided on the inner wall of the first rotor between the first fixed flange and the first rotor. A first sealing element is provided at the end of the first heat insulation layer away from the first fixed flange, between the first drive motor and the first pipe. The outer cylindrical surface of the first sealing element is configured as a plurality of annular sealing platform structures with a trapezoidal cross-section. The first stator is fixedly and sealedly connected to the first pipe flange and the first upper flange of the first pipe, respectively.

[0010] Preferably, the second heat collection tube is installed inside the second vacuum tube and extends out of the second vacuum tube with sealed ends. There is a cavity between the second heat collection tube and the second vacuum tube, and a spiral heat conductor is installed on the outer section of the second heat collection tube inside the cavity. The upper and lower ends of the spiral heat conductor are respectively provided with a solution inlet and a solution outlet that pass through the side wall of the second heat collection tube. The solution inlet and solution outlet are close to the salt inlet and the salt outlet, respectively. The two ends of the second heat collection tube are respectively provided with a second upper flange and a second lower flange. The second upper flange is fixedly connected to the output end of the solenoid valve. The second spiral scraper mechanism includes a second drive motor and a Fresnel salt collecting auger fixedly connected to its second rotor. The Fresnel salt collecting auger is axially installed inside the second heat collection tube and maintains movable contact with the inner wall of the second heat collection tube. The two ends of the second stator of the second drive motor are fixedly connected to the second lower flange and the third flange of the third output tube, respectively.

[0011] Preferably, the Fresnel salt collecting auger includes a second spiral blade with a trapezoidal cross-section and a second fixed flange fixedly installed at its end. The second spiral blade has a second inner hole for feeding. The cross-section of the second spiral blade decreases from the feed end to the discharge end. The second fixed flange is fixedly connected to the second rotor. An integral second heat insulation layer is provided between the second fixed flange and the second rotor and on the inner wall of the second rotor. A second sealing element is provided at the end of the second heat insulation layer away from the second fixed flange. The outer cylindrical surface of the second sealing element is configured as a structure of multiple annular sealing platforms with a trapezoidal cross-section.

[0012] Preferably, the above-mentioned salt discharge port is equipped with an output valve, and the output end of the third output pipe is connected to the salt collection box, which is installed at the bottom of the support.

[0013] Preferably, the reflector is fixedly installed below the first heat collector tube by a reflector bracket. The reflector has a strip-shaped parabolic structure, and the inner wall of the parabolic surface is coated with a mirror-like heat-insulating and reflective coating. The central axis of the first heat collector tube is set at the focal point of the parabolic surface. The linear Fresnel convex lens is fixedly installed above the second heat collector tube by a Fresnel lens bracket. The central axis of the second heat collector tube is set at the focal length of the linear Fresnel convex lens.

[0014] Preferably, the support includes a crossbar and left and right vertical plates fixed at both ends of the crossbar. A first and second middle vertical plate are symmetrically arranged between the left and right vertical plates. The top ends of the left and right vertical plates are respectively provided with a left mounting hole and a right mounting hole for the heat collector tube. The end of the second heat collector tube is fixedly connected to the left vertical plate through the left mounting hole, and the head end of the first heat collector tube is fixedly connected to the right vertical plate through the right mounting hole. The top ends of the first and second middle vertical plates are provided with a left mounting hole and a right mounting hole for the heat exchanger. The left and right ends of the heat exchanger are respectively fixedly connected to the first and second middle vertical plates through the left and right mounting holes. The saltwater outlet of the heat exchanger is located at the right end and connected to the first pipe through a flange. A right through hole is opened in the middle of the right vertical plate corresponding to the first pipe. The first pipe passes through the right vertical plate through the right through hole and connects to the first heat collector tube. A left through hole is opened on the left vertical plate corresponding to the right through hole.

[0015] Preferably, the output end of the first rotary motor is fixedly connected to the middle of the bottom end of the bracket, the input end of the first rotary motor is fixedly connected to the output end of the second rotary motor, the input end of the second rotary motor is fixedly connected to the output end of the third rotary motor, and the axes of the first rotary motor, the second rotary motor, and the third rotary motor are perpendicular to each other, forming an orthogonal RRR three-axis transmission system to provide spherical motion for the axial flow cascade and heat exchanger.

[0016] Preferably, the input end of the third rotation is fixedly connected to the top of the pole, the bottom end of the pole is fixed to the ground by a flange, the middle part of the pole is connected to a salt collection box by a hose clamp, the salt collection box is connected to the salt discharge port through a third output pipe, a salt collection port is opened at the bottom of the salt collection box, and a valve is provided at the salt collection port.

[0017] The operation method of a cascaded axial flow brine crystallization system is as follows: Brine is preheated by being forced into a heat exchanger. The brine, reaching a temperature of 60℃-80℃, enters the first heat collector tube of the photothermal salt collection module. A first drive motor drives the photothermal salt collection auger in reverse to stir the brine, ensuring uniform heating. The brine temperature reaches 85℃-160℃, promoting water evaporation. The steam is then discharged to the heat exchanger through a second pipe. Inside the heat exchanger, the newly entered brine is preheated and the steam is condensed. After a period of time, the first drive motor rotates in the forward direction, using the first rotating blades of the photothermal salt collection auger to crystallize the brine in the first heat collector tube. The viscous crystalline salt inside and on the inner wall of the first heat collector tube is scraped and transported. When the solenoid valve is opened, the photothermal salt collecting auger outputs the viscous crystalline salt to the Fresnel salt collecting module. With the support of the linear Fresnel mirror, the second vacuum tube, and the spiral heat conductor, the internal temperature of the second heat collector tube reaches over 200°C. The second drive motor drives the Fresnel salt collecting auger in reverse to stir the viscous crystalline salt, causing it to undergo secondary heating and evaporation. After a period of time, the second drive motor drives in the forward direction, using the second spiral blades to scrape off the crystalline salt adhering to the inner wall of the second heat collector tube. Finally, the crystalline salt is output through the third output tube.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The cascaded axial flow technology of photothermal salt collection and Fresnel salt collection of the present invention first heats the saline water to a set temperature through photothermal salt collection and performs a first crystallization to obtain viscous crystalline salt. The obtained viscous crystalline salt is then sent to the Fresnel salt collection module for secondary crystallization, so that the saline water to salt crystallization achieves single-end entry and single-end output, reducing the original water-vapor-heat three-phase separation process and making the structure simpler; the saline water crystallization process is gradually heated, and the temperature is higher than that of a single photothermal salt collection system or Fresnel salt collection system, making the saline water crystallization process more efficient; it realizes the low-energy water-salt resource collection of saline water and solves the problems of high energy consumption and low efficiency of existing saline water evaporation and crystallization. (2) The photothermal salt collection module and the Fresnel salt collection module are connected in series to form a cascaded axial flow structure using electromagnetic valves, and in conjunction with the first spiral scraper mechanism and the second spiral scraper mechanism, the crystallized salt of the photothermal salt collection module can be stirred and quickly discharged, and the crystallized salt of the Fresnel salt collection module can be stirred and quickly discharged. Stirring in the Fresnel salt collection module realizes that the recrystallization after the primary crystallization of the crystallized salt is fully and quickly secondary crystallization, resulting in higher crystallization efficiency. (3) The steam collected by the heat exchanger is used to preheat the brine. The preheated brine enters the photothermal salt collection module for primary crystallization, which reduces the heating time of the brine, shortens the crystallization time, further improves the crystallization efficiency and realizes energy recovery. (4) The first vacuum tube is equipped with a unidirectional light coating layer and a heat insulation coating layer, which can realize the concentration of light and reduce heat loss, thereby improving the energy utilization rate of light; the first spiral scraper mechanism can ensure that the drive motor can drive the photothermal salt collecting auger to rotate and deliver the crystallized salt while the material is being fed through. (5) The first helical blade with an L-shaped cross section promotes stirring during the evaporation and crystallization of salt water. When recrystallized salt is output, it can better drive the transport of crystallized salt (or salt viscous liquid). Moreover, the L-shaped helical blade has higher rigidity and strength, higher rotational stability, and the L-shaped structure is also more conducive to stirring and transporting after crystallization. (6) The second heat pipe is equipped with a spiral heat conductor and Fresnel heating, which makes the second heat pipe more uniformly heated, higher in temperature, faster crystallization, more efficient, and more stable in crystallization. (7) The trapezoidal second spiral blade increases the contact area of ​​the crystallized salt compared with the rectangular blade. The inclined plane of the trapezoid further improves the propulsion process of the crystallized salt. The sharp blade at the small end of the trapezoid can also increase the scraping force of the blade on the crystallized salt adhering to the inner wall of the second heat collector tube. (8) The crystallized salt can be transported to the salt collection box through the second spiral blade through the output valve; it is convenient to collect and then transfer the salt; the first rotary motor, the second rotary motor, and the third rotary motor form an orthogonal RRR three-axis transmission system. Compared with the RR two-axis transmission system of the photothermal salt collection system or the Fresnel salt collection system, the light tracking is more precise and the utilization efficiency of light energy is greatly improved. (9) By placing the focal point of the reflector on the central axis of the first heat collector tube, or the focal length of the linear Fresnel lens on the central axis of the second heat collector tube, the heating effect can be maximized and the utilization of light energy can be improved. (10) The salt water crystallization system is used to preheat the salt water to 60℃-80℃ through a heat exchanger and then enter the first heat collection tube of the photothermal salt collection module to be heated to 85℃-160℃ for one crystallization. After the set time is reached, it is sent into the second heat collection tube and heated to above 200℃ for crystallization, which can improve the crystallization efficiency and energy utilization. (11) This system can utilize the solar energy resources in nature and drive the heat collection method through the natural force of radiation energy to collect, evaporate, condense and recycle the water in the saline water resources; it can concentrate, crystallize and collect the salt in the saline water resources, realize the water and salt resource treatment of saline water resources, and provide beneficial technical support for the treatment of saline-alkali land in arid areas and saline water in coastal areas of my country. In summary, this invention utilizes a cascaded axial flow technology combining a heat exchanger, solar thermal salt collection, and Fresnel salt collection, and condenses and recovers saline water vapor to achieve low-energy-consumption, resource-efficient collection of saline water. This solves the problems of high energy consumption and low efficiency in existing saline water evaporation and crystallization methods. Compared to a single photothermal salt collection system or a Fresnel salt collection system, it has the following advantages: ①Through axial flow cascade technology, the process of salt water crystallization is achieved by single-end entry and single-end exit, reducing the original three-phase separation process of water-vapor-heat and making the structure simpler; ② An axial flow cascade structure is adopted to gradually heat the salt water crystallization process, resulting in a higher temperature than a single photothermal salt collection system or Fresnel salt collection system, making the salt water crystallization process more efficient. ③ Compared with the Fresnel salt collection system, a spiral heat conductor and a vacuum tube were added to the outside of the second heat collection tube, which made the second heat collection tube heat more evenly heated and at a higher temperature; ④ A first rotary motor, a second rotary motor, and a third rotary motor were added to form an orthogonal RRR three-axis transmission system. Compared with the RR two-axis transmission system of the photothermal salt collection system or the Fresnel salt collection system, the light tracking is more precise and the utilization efficiency of light energy is greatly improved. ⑤ The newly added L-shaped first spiral blade promotes stirring during the evaporation and crystallization process of salt water, and can better drive the transport of crystallized salt (or viscous salt liquid) when recrystallized salt is output; ⑥ The newly added trapezoidal second helical blades, compared with rectangular blades, increase the contact area of ​​the crystallized salt and further improve the propulsion process of the crystallized salt by utilizing the inclined surface of the trapezoid. The sharp blades at the small end of the trapezoid can also increase the scraping force of the blades on the crystallized salt adhering to the inner wall of the second heat collector tube. Attached Figure Description

[0019] Figure 1 A schematic diagram of the three-dimensional structure of a cascaded axial flow brine crystallization salt system; Figure 2 A side view of a cascaded axial flow brine crystallizing salt system; Figure 3 A front view schematic diagram of a cascaded axial flow brine crystallizing salt system; Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure of the middle AA section; Figure 5 This is a schematic diagram of the structure at the first heat pipe. Figure 6 A schematic diagram of the support structure and brackets for a cascaded axial flow brine crystallizing salt system; Figure 7 A schematic diagram of the heat exchanger structure of a cascaded axial flow brine crystallizing salt system; Figure 8 A schematic diagram of the photothermal salt collection module structure of a cascaded axial flow brine crystallization salt system; Figure 9 A schematic diagram of the Fresnel salt collection module structure of a cascaded axial flow brine crystallization salt system; Figure 10 A schematic diagram of the spiral heat conductor assembly for a cascaded axial flow brine crystallizing salt system. Figure 11 for Figure 4 Enlarged structural diagram of section A in the middle; Figure 12 for Figure 4 Enlarged structural diagram of section B. Detailed Implementation

[0020] The present invention will be further explained and described below with reference to the accompanying drawings to enable those skilled in the art to better understand it.

[0021] Example 1 like Figure 1-12 As shown, a cascaded axial flow brine crystallization system includes a photothermal salt collection module 1, a Fresnel salt collection module 2, a heat exchanger 3, a support 4, a first drive motor 5, a second drive motor 6, a solenoid valve 7, a first pipe 8, a second pipe 9, a third output pipe 10, a first rotary motor 11, a second rotary motor 12, a third rotary motor 13, a support pole 14, and a salt collection box 15.

[0022] The aforementioned photothermal salt collection module 1 and Fresnel salt collection module 2 are fixedly mounted on the bracket 4. The photothermal salt collection module 1 includes a first heat collection tube 101 and a reflector 102. The first heat collection tube 101 is fixedly mounted above the bracket 4, and the reflector 102 is fixedly mounted below the first heat collection tube 101. The light focused by the reflector 102 can irradiate the first heat collection tube 101 for heating. The first heat collection tube 101 has an inner cavity for containing saline water and an inlet 103 and a salt outlet 104 communicating with the inner cavity. And exhaust port 105; Fresnel salt collection module 2 includes a second heat collection tube 201 and a linear Fresnel convex lens 202. The second heat collection tube 201 is fixedly installed on the bracket 4 and the linear Fresnel convex lens 202 is fixedly installed above the second heat collection tube 201. The light focused by the linear Fresnel convex lens 202 can irradiate the second heat collection tube 201 for heating. The second heat collection tube 201 has an inner cavity and a salt inlet 203 and a salt outlet 204 communicating with the inner cavity. The salt outlet 104 is connected to the salt inlet 203. By employing a cascaded axial flow technology combining photothermal and Fresnel salt collection, the saline water is first heated to a set temperature and undergoes primary crystallization to obtain viscous crystalline salt. This viscous crystalline salt is then fed into a Fresnel salt collection module for secondary crystallization. This allows for single-end entry and single-end exit of the saline water to salt crystallization process, reducing the need for the original three-phase separation of water, vapor, and heat, resulting in a simpler structure. The saline water crystallization process is progressively heated to temperatures higher than either a single photothermal or Fresnel salt collection system, making the process more efficient. This achieves low-energy-consumption, water-salt resource collection of saline water, solving the problems of high energy consumption and low efficiency in existing saline water evaporation and crystallization methods.

[0023] A solenoid valve 7 is installed on the pipe connecting the salt outlet 104 and the salt inlet 203. The center lines of the solar thermal salt collection module 1, the solenoid valve 7, and the Fresnel salt collection module 2 are coaxial, forming an axial flow cascade. A first spiral scraper mechanism is provided inside the first heat collection tube 101, which can push the material in the first heat collection tube 101 into the second heat collection tube 201. A second spiral scraper mechanism is provided inside the second heat collection tube 201, which can push the material in the second heat collection tube to the salt outlet 204. The solar thermal salt collection module and the Fresnel salt collection module are connected in series by a solenoid valve to form a cascaded axial flow structure. With the cooperation of the first and second spiral scraper mechanisms, the crystallized salt in the solar thermal salt collection module can be stirred and quickly discharged, and the crystallized salt in the Fresnel salt collection module can be stirred and quickly discharged, respectively. The stirring in the Fresnel salt collection module achieves sufficient and rapid secondary crystallization after the primary crystallization of the crystallized salt, resulting in higher crystallization efficiency.

[0024] The inlet 103 of the first heat collector tube is located at the head end and is connected to the brine outlet 302 of the heat exchanger 3 via the first pipe 8. The heat exchanger 3 is mounted on the support 4 and also has a brine inlet 301. A condensate outlet 303 is located on the side wall of the heat exchanger 3 near the brine inlet 301, and a steam inlet 304 is located on the side wall of the heat exchanger 3 near the brine outlet 302. The steam inlet 304 is connected to the exhaust port 105 of the first heat collector tube 101 via the second pipe 9, and the condensate outlet 303 is connected to a water collection pipe. Steam collected by the heat exchanger is used to preheat the brine. The preheated brine enters the solar thermal salt collection module for primary crystallization, reducing the heating time of the brine, shortening the crystallization time, further improving crystallization efficiency, and realizing energy recovery.

[0025] To improve the system's light utilization efficiency, the aforementioned reflector 102 is fixedly installed below the first heat collection tube 101 via a reflector bracket 109. The reflector has a strip-shaped parabolic structure, and the inner wall of the parabolic surface is provided with a mirror-like heat-insulating and reflective coating. The center of the first heat collection tube 101 is located at the focal point of the parabolic surface, achieving mirror-like light focusing and maximizing the utilization efficiency of light energy. The central axis of the first heat collection tube 101 is located at the focal point of the parabolic surface. The first heat collection tube 101 is made of stainless steel, while the first vacuum tube 106 is made of glass. The first heat collection tube 101 is installed inside the first vacuum tube 106 and extends out of the first vacuum tube 106 with sealed ends. The first heat collection tube 101 and the first vacuum tube 106 are made of stainless steel. The vacuum collector is manufactured using a vacuum sintering and sealing process. The inner wall of the first vacuum tube 106 is provided with a unidirectional light coating layer 110 and a heat insulation coating layer 111 from the inside to the outside to prevent light from escaping from the first vacuum tube 106 and to transfer the temperature to the first heat collection tube 101. The first heat collection tube 101 is provided with a first upper flange 107 and a first lower flange 108 at both ends. The first spiral scraper mechanism includes a first drive motor 5 with a first connecting hole and a photothermal salt collection auger 16 fixedly connected to the first rotor 501 inside it. The first drive motor 5 is flange-connected to the first upper flange 107, and the other flange of the first drive motor 5 is flange-connected to the first pipe 8. The first lower flange 108 is connected to the input flange of the solenoid valve 7.The first rotor 501 has a bushing structure. The solar thermal salt collecting auger 16 is axially mounted on the inner wall of the first solar collector tube 101 to maintain movable contact. The solar thermal salt collecting auger 16 has a first discharge inner hole in the axial direction. The solar thermal salt collecting auger 16 includes a first helical blade 1601 with an L-shaped cross-section and a first fixed flange 1602 fixedly mounted on the head end of the first helical blade 1601. The first fixed flange 1602 is fixedly connected to the first rotor 501 of the first drive motor 5. The first rotor 501 drives the first fixed flange 1602 and the first helical blade 1601 to rotate, scraping off the crystallized salt on the inner wall of the first solar collector tube 101 and pushing it to the end of the first solar collector tube 101 to the maximum extent. In order to protect the normal operation of the first rotor 501, the first fixed flange 1602 and the inner wall of the first rotor 501 are provided with a first heat insulation layer 502. The first insulation layer 502 is provided with a first sealing element 503 at the end away from the first fixed flange 1602, which is between the first drive motor and the first pipe 8. The outer cylindrical surface of the first sealing element 503 is configured as a multi-ring sealing platform structure with a trapezoidal cross section to ensure the connection sealing between the first fixed flange 1602 and the first drive motor 5. In order to ensure the driving force of the first drive motor 5 on the first spiral scraper mechanism, one end of the first stator 504 of the first drive motor 5 is fixedly connected to the first upper flange 107, and the other end of the first stator 504 of the first drive motor 5 is fixedly connected to the first pipe flange 801. The first lower flange is fixedly connected to the input end of the solenoid valve 7. A first sealing gasket 505 and a second sealing gasket 506 are respectively provided between the first stator 504 and the first pipe flange 801 and the first upper flange 107, and are fastened with bolts. The first spiral scraper mechanism ensures that the drive motor can drive the photothermal salt collecting auger to rotate and deliver the crystallized salt while the material is being fed through. The first spiral blade with an L-shaped cross-section promotes stirring during the evaporation and crystallization of salt water. It can better drive the transport of crystallized salt (or viscous salt liquid) when the crystallized salt is output. Moreover, the L-shaped spiral blade has higher rigidity and strength, higher rotational stability, and the L-shaped structure is also more conducive to stirring and transporting the crystallized salt after it is produced.

[0026] The linear Fresnel lens 202 is fixedly mounted above the second heat collector 201 via the Fresnel lens bracket 211. The center of the second heat collector 201 is set at the focal length of the linear Fresnel lens 202 to improve the utilization rate of light energy. The second heat collector tube 201 is made of stainless steel, and the second vacuum tube 205 is made of glass. The second heat collector tube 201 is installed inside the second vacuum tube 205 and extends out of the second vacuum tube 205 with sealed ends. The second heat collector tube 201 and the second vacuum tube 205 are manufactured using a vacuum sintering sealing process. There is a cavity between the second heat collector tube 201 and the second vacuum tube 205, and a spiral heat conductor 206 is coiled on the outer section of the second heat collector tube 201 inside the cavity. The upper and lower ends of the spiral heat conductor 206 are respectively provided with a solution inlet 209 and a solution outlet 210 that pass through the side wall of the second heat collector tube 201. The solution inlet 209 and the solution outlet 210 are close to the salt inlet 203 and the salt outlet 204, respectively. The installation of the spiral heat conductor 206 on the second heat collector tube 201, in conjunction with Fresnel heating, makes the second heat collector tube 201 more uniformly heated, with higher temperature, faster crystallization, higher efficiency, and more stable crystallization.

[0027] The second heat collector tube 201 has a second upper flange 207 and a second lower flange 208 at both ends. The second upper flange 207 is fixedly connected to the output end of the solenoid valve 7. The second spiral scraper mechanism includes a second drive motor 6 and a Fresnel salt collecting auger 17 fixedly connected to its second rotor 601. The second drive motor 6 is fixedly connected to the second lower flange 208. The Fresnel salt collecting auger 17 is axially installed along the inside of the second heat collector tube 201 and maintains movable contact with the inner wall of the second heat collector tube. The Fresnel salt collecting auger 17 includes a second spiral blade with a trapezoidal cross-section and a second fixed flange fixedly installed at the end of the second spiral blade. The second spiral blade has a second inner hole for feeding. The cross-section of the second spiral blade decreases from the feed end to the discharge end. Compared with rectangular blades, the trapezoidal second spiral blade increases the contact area of ​​the crystallized salt and further improves the propulsion process of the crystallized salt by utilizing the inclined surface of the trapezoid. The sharp blade at the small end of the trapezoid can also increase the scraping force of the blade on the crystallized salt adhering to the inner wall of the second heat collector tube. The second fixed flange is fixedly connected to the second rotor 601 of the second drive motor 6. The second rotor 601 drives the second fixed flange and the second spiral blade to rotate, scraping off the crystallized salt on the inner wall of the second heat collection tube 201 and pushing it to the salt outlet 204 to the maximum extent. In order to avoid the high temperature deformation of the second rotor affecting the operation, a second heat insulation layer 602 is provided between the second fixed flange and the second rotor 601 and the inner wall of the second rotor. The end of the second heat insulation layer 602 away from the second fixed flange is provided with a second sealing element 603 that elastically seals the salt outlet 204 of the second heat collection tube 201 and the second rotor 601. The outer cylindrical surface of the second sealing element 603 is set as a multi-ring sealing platform structure with a trapezoidal cross section. The second stator 604 of the second drive motor 6 is fixedly connected to the third pipe flange 1001 and the second lower flange 208 of the third output pipe 10. A third sealing gasket 605 and a fourth sealing gasket 606 are provided between the second stator 604 and the third pipe flange 1001 and the second lower flange 208, respectively, and are fastened with bolts.

[0028] The salt outlet 204 of the second heat collector tube 201 is located at the end and is equipped with an output valve 18. During crystallization, the output valve 18 is used to seal the second heat collector tube 201. The salt outlet 204 is fixedly connected to the second drive motor 6. The other end of the second drive motor 6 is connected to the third output tube 10. The output end flange of the third output tube 10 is connected to the salt collection box 15. The salt collection box 15 is installed at the lower part of the bracket 4. Through the output valve, the crystallized salt can be transported to the salt collection box through the second spiral blades for easy collection and transfer. The side wall of the second heat collector tube 201 is provided with a solution inlet 209 near the salt inlet 203 and a solution outlet 210 near the salt outlet 204. Clean water can be pressurized into the second heat collector tube through the solution inlet to rinse it and flow out from the solution outlet. During use, the solution inlet and solution outlet are closed.

[0029] Furthermore, the aforementioned support 4 includes a crossbar 401 and a left vertical plate 402 and a right vertical plate 403 fixed at both ends of the crossbar 401. A first middle vertical plate 404 and a second middle vertical plate 405 are provided between the left vertical plate 402 and the right vertical plate 403. The first middle vertical plate 404 and the second middle vertical plate 405 are symmetrical about the central axis of the crossbar 401. The top ends of the left vertical plate 402 and the right vertical plate 403 are respectively provided with a left mounting hole 4021 and a right mounting hole 4031 for the heat collection tube. The end of the second heat collection tube 201 is fixedly connected to the left vertical plate 402 through the left mounting hole 4021, and the first heat collection tube 101 is fixed to the right vertical plate 403 through the right mounting hole 4031. The first central plate 404 and the second central plate 405 are provided with a left mounting hole 4041 and a right mounting hole 4042 for the heat exchanger at their top ends. The left and right ends of the heat exchanger 3 are fixedly connected to the first central plate 404 and the second central plate 405 through the left mounting hole 4041 and the right mounting hole 4051, respectively. The salt water outlet of the heat exchanger 3 is located at the right end and is connected to the first pipe 8 through a flange. A right through hole 4032 is opened in the middle of the right plate 403 corresponding to the first pipe 8. The first pipe 8 passes through the right plate 403 through the right through hole 4032 and is connected to the first drive motor 5. A left through hole 4022 is opened on the left plate 402 corresponding to the right through hole 4032.

[0030] The output end of the first rotary motor 11 is fixedly connected to the middle of the crossbar 401 of the aforementioned bracket 4. The first rotary motor 11 drives the bracket 4 to swing left and right. The input end of the first rotary motor 11 is fixedly connected to the output end of the second rotary motor 12. The second rotary motor 12 drives the first rotary motor 11 and the bracket to pitch. The input end of the second rotary motor 12 is fixedly connected to the output end of the third rotary motor 13. The third rotary motor 13 rotates. The axes of the first rotary motor 11, the second rotary motor 12, and the third rotary motor 13 are perpendicular to each other, forming an orthogonal RRR three-axis transmission system, providing spherical motion for the axial flow cascade and heat exchanger. Compared with the RR two-axis transmission system of the photothermal salt collection system or the Fresnel salt collection system, the first rotary motor, the second rotary motor, and the third rotary motor form an orthogonal RRR three-axis transmission system, which provides more precise light tracking and greatly improves the utilization efficiency of light energy.

[0031] Among them, the bracket 4 is equipped with a light-sensing tracking system, which includes a sensing unit and a control unit. The sensing unit collects parameters such as rotation angle, pitch angle, wind speed, temperature, humidity, and light intensity. The control unit receives the data from the sensing unit, controls the movement of the three-axis transmission system, and adjusts the axial-flow cascade to the optimal posture.

[0032] Furthermore, the input end of the aforementioned third rotary motor 13 is fixedly connected to the top of the upright 14, the bottom end of the upright 14 is fixed to the ground by a flange, and the middle part of the upright 14 is connected to the salt collection box 15 by a hose clamp. The salt collection box 15 is connected to the salt discharge port 204 through the third output pipe 10.

[0033] Example 2 A method for using a cascaded axial flow brine crystallization system is as follows: Brine is preheated by being forced into a heat exchanger. The brine, reaching a temperature of 60℃-80℃, enters the first heat collector tube of the photothermal salt collection module. A first drive motor drives the photothermal salt collection auger in reverse to stir the brine, ensuring uniform heating. The brine temperature reaches 85℃-160℃, promoting water evaporation. The steam is then discharged through a second pipe to the heat exchanger. Inside the heat exchanger, the newly entered brine is preheated and the steam is condensed. After a period of time, the first drive motor rotates in the forward direction, using the first rotating blades of the photothermal salt collection auger to crystallize the brine in the first heat collector tube. The viscous crystalline salt inside and on the inner wall of the heat pipe is scraped and transported. When the solenoid valve opens, the photothermal salt collecting auger outputs the viscous crystalline salt to the Fresnel salt collecting module. With the support of the linear Fresnel mirror, the second vacuum tube, and the spiral heat conductor, the internal temperature of the second heat collecting tube reaches over 200°C and the pressure is 80 kPa. The second drive motor drives the Fresnel salt collecting auger in reverse to stir the viscous crystalline salt, causing it to undergo secondary heating and evaporation. After a period of time, the second drive motor drives in the forward direction, using the second spiral blades to scrape off the crystalline salt adhering to the inner wall of the second heat collecting tube. Finally, the crystalline salt is output through the third output tube.

[0034] The brine crystallization system is used by preheating brine to 60℃-80℃ through a heat exchanger and then heating it to 85℃-160℃ in the first heat collector tube of the solar thermal salt collection module for one crystallization. After the set time is reached, the brine is sent to the second heat collector tube and heated to above 200℃ for crystallization, which can improve crystallization efficiency and energy utilization.

[0035] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit and principles thereof should fall within the protection scope defined by the claims of the present invention.

Claims

1. A cascaded axial flow saline water crystallization system, characterized in that, The system includes a photothermal salt collection module (1) and a Fresnel salt collection module (2) that are fixedly mounted side by side on a bracket (4). The photothermal salt collection module (1) includes a first heat collection tube (101) and a reflector (102). The first heat collection tube (101) is fixedly mounted above the bracket (4), and the reflector (102) is fixedly mounted below the first heat collection tube (101). The light focused by the reflector (102) can irradiate the first heat collection tube (101) for heating. The first heat collection tube (101) has an inner cavity for containing salt water and an inlet (103) and an outlet (104) connected to the inner cavity. The Fresnel salt collection module (2) includes a second heat collection tube (201) and a linear Fresnel convex lens (202). The second heat collection tube (201) is fixedly installed on the bracket (4) and the linear Fresnel convex lens (202) is fixedly installed above the second heat collection tube (201). The light focused by the linear Fresnel convex lens (202) can irradiate the second heat collection tube (201) for heating. The second heat collection tube (201) is provided with an inner cavity and a salt inlet (203) and a salt outlet (204) communicating with the inner cavity. The salt outlet (104) is connected to the salt inlet (203). A solenoid valve (7) is installed on the pipe connecting the salt outlet (104) and the salt inlet (203). The center lines of the solar thermal salt collection module (1), the solenoid valve (7) and the Fresnel salt collection module (2) are coaxial, forming an axial flow cascade. A first spiral scraper mechanism is provided in the first heat collection tube (101). The first spiral scraper mechanism can push the material in the first heat collection tube (101) to the second heat collection tube (201). A second spiral scraper mechanism is provided in the second heat collection tube (201). The second spiral scraper mechanism can push the material in the second heat collection tube to the salt outlet (204). The second heat collector tube (201) is installed inside the second vacuum tube (205) and extends out of the second vacuum tube (205) with both ends sealed. There is a cavity between the second heat collector tube (201) and the second vacuum tube (205), and a spiral heat conductor (206) is installed on the outer section of the second heat collector tube (201) inside the cavity. The upper and lower ends of the spiral heat conductor (206) are respectively provided with a solution inlet (209) and a solution outlet (210) passing through the side wall of the second heat collector tube (201). The solution inlet (209) and the solution outlet (210) are close to the salt inlet (203) and the salt outlet (204) respectively. The second heat collector tube (201) is installed inside the second vacuum tube (205) with both ends sealed. 01) The two ends are respectively provided with a second upper flange (207) and a second lower flange (208). The second upper flange (207) is fixedly connected to the output end of the solenoid valve (7). The second spiral scraper mechanism includes a second drive motor (6) and a Fresnel salt collecting auger (17) fixedly connected to its second rotor (601). The Fresnel salt collecting auger (17) is installed axially along the inside of the second heat collecting tube (201) and maintains active contact with the inner wall of the second heat collecting tube. The two ends of the second stator (604) of the second drive motor (6) are fixedly connected to the second lower flange (208) and the third pipe flange (1001) of the third output pipe (10), respectively. The Fresnel salt collecting auger (17) includes a second spiral blade with a trapezoidal cross-section and a second fixed flange fixedly installed at its end. The second spiral blade is provided with a second inner hole for feeding. The cross-section of the second spiral blade decreases from the feed end to the discharge end. The second fixed flange is fixedly connected to the second rotor (601). A second heat insulation layer (602) is integrally provided between the second fixed flange and the second rotor (601) and the inner wall of the second rotor (601). The end of the second heat insulation layer (602) away from the second fixed flange is provided with a second sealing element (603) for the salt discharge port (204) of the second heat collecting tube (201) and the second rotor (601). The outer cylindrical surface of the second sealing element (603) is configured as a multi-ring sealing platform structure with a trapezoidal cross-section.

2. The cascaded axial flow saline water crystallization system according to claim 1, characterized in that, The inlet (103) of the first heat collector tube (101) is located at the head end and the inlet (103) is connected to the brine outlet (302) of the heat exchanger (3) through the first pipe (8). The heat exchanger (3) is mounted on the bracket (4) and the heat exchanger (3) is also provided with a brine inlet (301). A condensate outlet (303) is provided at one end of the side wall of the heat exchanger (3) near the brine inlet (301). A steam inlet (304) is provided at one end of the side wall of the heat exchanger (3) near the brine outlet (302). The steam inlet (304) is connected to the exhaust port (105) of the first heat collector tube (101) through the second pipe (9). The condensate outlet (303) is connected to the water collection pipe.

3. The cascaded axial flow saline water crystallization system according to claim 1, characterized in that, The first heat collector tube (101) is installed inside the first vacuum tube (106) and extends out of the first vacuum tube (106) with sealed ends. The inner wall of the first vacuum tube (106) is provided with a unidirectional light coating layer (110) and a heat insulation coating layer (111) from the inside to the outside. The first heat collector tube (101) is provided with a first upper flange (107) and a first lower flange (108) at both ends. The first spiral scraper mechanism includes a first drive motor (5) and a photothermal salt collecting auger (16) fixedly connected to the first rotor (501) inside it. The first rotor (501) is a shaft. The structure is as follows: the solar thermal salt collecting auger (16) is axially installed inside the first heat collecting tube (101) and maintains active contact with the inner wall of the first heat collecting tube (101). The solar thermal salt collecting auger (16) is provided with a first discharge inner hole in the axial direction. One end of the first stator (504) of the first drive motor (5) is fixedly and sealed to the first upper flange (107). The other end of the first stator (504) of the first drive motor (5) is fixedly and sealed to the first pipe flange (801) of the first pipe (8). The first lower flange (108) is fixedly and sealed to the input end of the solenoid valve (7).

4. The cascaded axial flow saline water crystallization system according to claim 3, characterized in that, The photothermal salt collecting auger (16) includes a first helical blade (1601) with an L-shaped cross section and a first fixed flange (1602) fixedly installed at its head end. The first fixed flange (1602) is fixedly connected to the first rotor (501). An integral first heat insulation layer (502) is provided between the first fixed flange (1602) and the first rotor (501) and on the inner wall of the first rotor (501). A first sealing element (503) is provided at one end of the first heat insulation layer (502) away from the first fixed flange (1602) between the first drive motor and the first pipe (8). The outer cylindrical surface of the first sealing element (503) is configured as a multi-annular sealing platform structure with a trapezoidal cross section.

5. A cascaded axial flow saline water crystallization system according to claim 1, characterized in that, The salt outlet (204) is equipped with an output valve (18), and the output end of the third output pipe (10) is connected to the salt collection box (15). The salt collection box (15) is installed at the lower part of the bracket (4). The output end of the first rotary motor (11) is fixedly connected to the middle of the bottom end of the bracket (4). The input end of the first rotary motor (11) is fixedly connected to the output end of the second rotary motor (12). The input end of the second rotary motor (12) is fixedly connected to the output end of the third rotary motor (13). The axes of the first rotary motor (11), the second rotary motor (12), and the third rotary motor (13) are perpendicular to each other and together form an orthogonal RRR three-axis transmission system to provide spherical motion for the axial flow cascade and heat exchanger.

6. The cascaded axial flow saline water crystallization system according to claim 1, characterized in that, The reflector (102) is fixedly installed below the first heat collection tube (101) by the reflector bracket (109). The reflector is a strip-shaped parabolic structure, and the inner wall of the parabolic surface is provided with a mirror heat insulation and reflective coating. The central axis of the first heat collection tube (101) is set at the focal point of the parabolic surface. The linear Fresnel convex lens (202) is fixedly installed above the second heat collection tube (201) by the Fresnel lens bracket (211). The central axis of the second heat collection tube (201) is set at the focal length of the linear Fresnel convex lens (202).

7. The method of using a cascaded axial flow saline water crystallization system according to claim 1, characterized in that, The method is as follows: Salt water is preheated by pressing it into a heat exchanger. When the temperature of the salt water reaches 60℃-80℃, it enters the first heat collection tube of the solar thermal salt collection module from the heat exchanger. The first drive motor drives the solar thermal salt collection auger in the reverse direction to stir the salt water, so that the salt water is heated evenly. When the temperature of the salt water reaches 85℃-160℃, the water in the salt water evaporates. The steam generated by evaporation is discharged to the heat exchanger through the second pipe. Inside the heat exchanger, the newly entered salt water is preheated and the steam is condensed. After the set time is reached, the first drive motor rotates in the forward direction. The first rotating blade of the solar thermal salt collection auger scrapes and transports the viscous crystallized salt inside and on the inner wall of the first heat collection tube. The solenoid valve opens, and the photothermal salt collecting auger outputs the viscous crystalline salt to the Fresnel salt collecting module. With the support of the linear Fresnel lens, the second vacuum tube, and the spiral heat conductor, the internal temperature of the second heat collecting tube reaches over 200°C. The second drive motor drives the Fresnel salt collecting auger in reverse to stir the viscous crystalline salt, causing it to undergo secondary heating and evaporation. After a period of time, the second drive motor drives in the forward direction, using the second spiral blades to scrape off the crystalline salt adhering to the inner wall of the second heat collecting tube. Finally, the crystalline salt is output through the third output tube.

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