A device for recycling saline-alkali soil leaching water

Abstract

The application belongs to the technical field of saline-alkali soil treatment, and particularly relates to a saline-alkali soil leaching water recycling device, which comprises a water collecting well for collecting leaching water, a heating module arranged at the bottom of the water collecting well and used for heating and evaporating the leaching water to form water vapor, a steam channel comprising a first conical pipe, a straight pipe and a second conical pipe arranged coaxially in sequence, the first conical pipe and the second conical pipe are respectively provided with an inlet end and an outlet end, the diameter of the inlet end of the first conical pipe is larger than that of the outlet end, the diameter of the inlet end of the second conical pipe is smaller than that of the outlet end, the diameters of the outlet end of the first conical pipe and the inlet end of the second conical pipe are the same as that of the straight pipe, the inlet end of the first conical pipe is communicated with the heating module, a condensing module connected to the outlet end of the second conical pipe and used for cooling the water vapor into condensed water, and a power supply module comprising a solar power generation assembly and a wind power generation assembly and used for ensuring power supply.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of saline-alkali soil treatment, and particularly relates to a saline-alkali soil leaching water recycling device. BACKGROUND

[0002] Scientific management of saline-alkali soil is crucial to guarantee the national farmland red line and food security. At present, the salt washing technology by buried pipe drainage has become the mainstream method for saline-alkali soil improvement in arid regions because it can effectively regulate the groundwater level and reduce soil salinity. However, if the high-salinity leaching water (salt concentration of about 3.5%) generated by this technology is directly discharged, it will lead to an increase in the mineralization degree of the surrounding water body and an intensification of soil secondary salinization, which will pose a serious threat to the ecological environment.

[0003] Currently, the research on the recycling of saline-alkali soil leaching water mainly draws on seawater purification technologies, such as reverse osmosis membrane or microbial cell desalination method, to achieve desalination of coastal saline-alkali soil leaching water. However, in the arid regions of Ningxia and Gansu in Northwest China, the reverse osmosis membrane desalination method is prone to blockage due to the high salinity and high turbidity of the water quality in these regions, and the microbial cell desalination method is sensitive to temperature fluctuations and is easily affected by the large temperature difference in these regions. Therefore, it is difficult to adapt to the special environmental requirements of saline-alkali soil leaching water recycling in Northwest China, and the desalination efficiency of leaching water is low, and the desalination quality is difficult to guarantee. Therefore, there is an urgent need for a saline-alkali soil leaching water recycling device to adapt to the special environmental requirements of saline-alkali soil leaching water recycling in Northwest China. SUMMARY

[0004] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a saline-alkali soil leaching water recycling device which can adapt to different regional environments in the arid regions of Northwest China by utilizing natural resources such as solar energy and wind energy, improve the desalination efficiency and quality of leaching water, and has a simple structure and low operation and maintenance cost.

[0005] The technical scheme of the present application is as follows:

[0006] A saline-alkali soil leaching water recycling device, comprising:

[0007] A water collection well for collecting leaching water;

[0008] A heating module arranged at the bottom of the water collection well for heating the leaching water to evaporate and form water vapor;

[0009] A steam passage comprising a first conical pipe, a straight pipe and a second conical pipe arranged coaxially in sequence, the first conical pipe and the second conical pipe are respectively provided with an inlet end and an outlet end, the diameter of the inlet end of the first conical pipe is larger than that of the outlet end, the diameter of the inlet end of the second conical pipe is smaller than that of the outlet end, the outlet end of the first conical pipe and the inlet end of the second conical pipe are communicated through the straight pipe, and the inlet end of the first conical pipe is communicated with the output end of the heating module.

[0010] a condensing module connected to the outlet end of the second conical pipe for cooling the water vapor to form condensed water;

[0011] a power supply module comprising a solar power assembly and a wind power assembly for providing power for the heating module.

[0012] Preferably, the condensing module comprises:

[0013] a ring-shaped rectifier, the inlet of which is in communication with the outlet end of the second conical pipe;

[0014] a plurality of eccentric reducers, which are distributed in a circumferential array on the side of the ring-shaped rectifier, one end of the eccentric reducers being in communication with the ring-shaped rectifier;

[0015] a plurality of heat exchange assemblies corresponding to the plurality of eccentric reducers, the heat exchange assemblies being connected to the other end of the eccentric reducers for cooling the steam distributed to the eccentric reducers into condensed water.

[0016] Preferably, the heat exchange assembly comprises:

[0017] a steam distribution pipe, which is obliquely arranged, the lower end of the oblique direction being in communication with one end of the eccentric reducer away from the ring-shaped rectifier, and the other end being closed;

[0018] a plurality of heat exchange tube bundles, the heat exchange tube bundle comprising a heat dissipation pipe and a plurality of heat dissipation fins uniformly distributed on the outer side of the wall of the heat dissipation pipe, the heat dissipation pipe being a flat thin-walled structure, one end of the heat dissipation pipe being connected to the steam distribution pipe, and the other end being connected to a water collecting pipe, the water collecting pipe being used to communicate with a water storage tank to collect condensed water, the water storage tank being an annular cavity sleeved on the upper end of the second conical pipe.

[0019] Preferably, the upper end of the second conical pipe is further provided with an outer shell, the lower end of the outer shell being sleeved on the outer wall of the water storage tank and being fixedly connected thereto, the upper end of the outer shell being higher than the ring-shaped rectifier, the ring-shaped rectifier, the eccentric reducer, the steam distribution pipe and the heat exchange tube bundle being all arranged inside the outer shell, and the side wall of the outer shell being provided with louvers for allowing cold air to flow in and contact the heat exchange tube bundle and the heat dissipation fins.

[0020] Preferably, a fan is arranged between the top wall of the outer shell and the ring-shaped rectifier, the air inlet of the fan being arranged inside the outer shell, and the air outlet of the fan being arranged outside the outer shell through the top wall of the outer shell for discharging hot air in the outer shell.

[0021] Preferably, the top of the rectifier is arc-shaped, and the connection between the eccentric reducer and the ring-shaped rectifier is close to the second conical pipe.

[0022] Preferably, the steam passage is wrapped with a heat preservation layer on the outside and is provided with a salt protection layer on the inside.

[0023] Preferably, the heating module comprises:

[0024] a heating cavity fixed at the bottom of the water collecting well, the upper end of which is provided as an opening, the opening of the heating cavity being communicated with the inlet end of the first conical pipeline, for containing the leaching water entering the water collecting well;

[0025] a heating coil wound on the outer wall of the heating cavity;

[0026] a storage battery provided at the bottom of the heating cavity and electrically connected with the heating coil and the power supply module respectively.

[0027] Preferably, the heating coil adopts a high-temperature mica wrapped fiberglass cable.

[0028] Preferably, the outer side of the heating coil is wrapped with high-temperature heat insulation cotton for reducing heat loss.

[0029] Compared with the prior art, the salt and alkali land leaching water recycling device has the following beneficial effects:

[0030] The device is adapted to local conditions, considering the drought climate characteristics in the northwest, using solar energy and wind energy for power supply, combining with the water collecting well in the salt and alkali land, placing the heating module and the steam passage in the water collecting well, saving construction space and cost, and reducing interference; the steam passage of the device forms a structure similar to a Venturi tube through the first conical pipeline, the straight pipeline and the second conical pipeline, i.e. a steam passage with a "tapering-straight section-tapering expansion" structure, which can effectively improve the flow efficiency and stability of water vapor and reduce backflow, and then a condensing module is arranged at the outlet end of the second conical pipeline to realize cooling of water vapor into condensed water for recycling, the power supply module adopts a combination type power generation of a solar power generation assembly and a wind power generation assembly, fully adapting to the natural advantages of the northwest arid region, using natural resources to provide power support for the heating module and other electrical equipment, the device has no complex structure and precise parts, runs stably, is easy to maintain, can adapt to different regional demands, has strong practicality, and realizes efficient and stable desalination and recycling of leaching water in the northwest arid region, and the recycled water can be directly used for fresh water leaching or irrigation. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is an actual utilization schematic diagram of the device in the embodiment of the present application.

[0032] Figure 2 It is a schematic diagram of the overall structure of the device in the embodiment of the present application.

[0033] Figure 3The structure diagram of the heating module and the heating channel structure in the embodiment of the present application.

[0034] Figure 4 The structure diagram of the annular rectifier in the embodiment of the present application.

[0035] Figure 5 The structure diagram of the condensing module in the embodiment of the present application.

[0036] Figure 6 The velocity streamline diagram of the water vapor in the embodiment of the present application.

[0037] Figure 7 The velocity vector diagram of the water vapor in the embodiment of the present application.

[0038] Figure 8 The temperature change diagram in the steam channel in the embodiment of the present application.

[0039] Figure 9 The air pressure change diagram in the steam channel in the embodiment of the present application.

[0040] Explanation of reference signs:

[0041] 1, water collecting well, 2, heating module, 21, heating cavity, 22, heating coil, 3, steam channel, 31, first conical pipe, 32, straight pipe, 33, second conical pipe, 4, condensing module, 41, annular rectifier, 42, eccentric reducer, 43, steam distribution pipe, 44, heat exchange pipe bundle, 441, radiating pipe, 442, water collecting pipe, 5, power supply module, 6, louver, 7, water storage tank, 8, shell, 9, fan, 10, thermal insulation layer, 11, drainage pipe, 12, gravity pipe. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0043] Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0044] In addition, the technical schemes of various embodiments of the present application can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, when the combination of technical schemes appears contradictory or unachievable, it should be considered that the combination of technical schemes does not exist, and is not within the scope of protection required by the present application.

[0045] Reference Figures 1 to 5As shown, in order to adapt to different regional environments such as the arid regions in the northwest, realize efficient desalination and recycling of leaching water, ensure the stability of desalination quality, simplify the complexity of the structure, and reduce operation and maintenance costs. The embodiment provides a saline-alkali soil leaching water recycling device, which comprises a water collecting well 1, a heating module 2, a steam channel 3, a condensation module 4 and a power supply module 5.

[0046] The water collecting well 1 is directly constructed in the working area, specifically, the water collecting well 1 is formed into a vertical shaft by ground excavation, and the shaft wall is subjected to strengthening treatment. The leaching water is collected by the drainage blind pipe 11 and the blind pipe into the water collecting well 1. The heating module 2 is arranged at the bottom of the water collecting well 1, for bearing and heating the leaching water collected into the water collecting well 1 to form water vapor. The water vapor output port of the heating module 2 is connected with the steam channel 3. Specifically, the steam channel 3 comprises a first conical pipe 31, a straight pipe 32 and a second conical pipe 33 arranged coaxially in sequence, the first conical pipe 31 and the second conical pipe 33 are respectively provided with an inlet end and an outlet end, the diameter of the inlet end of the first conical pipe 31 is larger than that of the outlet end, the diameter of the inlet end of the second conical pipe 33 is smaller than that of the outlet end, and the diameter of the outlet end of the first conical pipe 31 and the diameter of the inlet end of the second conical pipe 33 are the same as the diameter of the straight pipe 32, and the outlet end of the first conical pipe 31 and the inlet end of the second conical pipe 33 are communicated through the straight pipe 32, the inlet end of the first conical pipe 31 is communicated with the water vapor output port of the heating module 2, for guiding the flow of water vapor while accelerating the flow of water vapor. Thus, the steam channel 3 forms a structure similar to a Venturi tube through the first conical pipe 31, the straight pipe 32 and the second conical pipe 33, i.e. a steam channel 3 with "tapering-straight section-tapering", which can effectively improve the flow efficiency and stability of water vapor, reduce backflow, and then use the condensation module 4 arranged at the outlet end of the second conical pipe 33 to cool the water vapor and form condensed water for recycling. The recycled water can be drunk or directly used for irrigation. At the same time, in order to adapt to the environment of the arid regions in the northwest and save costs, the power supply module 5 adopts a combined type power generation of a solar power generation assembly and a wind power generation assembly, fully adapts to the natural advantages of the arid regions in the northwest, and uses natural resources to provide power for the heating module 2 and other electrical equipment.

[0047] Further, the steam passage 3 is made of 316L stainless steel as a whole, with a wall thickness of 10 mm, and meets the functional requirements of each section through differential surface treatment and external structural design. Among them, the first conical pipeline 31 (tapered section) adopts plasma spraying NiCr-Cr3C2, with a coating thickness of 80 μm, to resist high-speed salt particle erosion. The straight pipeline 32 adopts electrolytic polishing, with Ra<0.8 μm, to reduce flow resistance and reduce salt mist adhesion. The second conical pipeline 33 (tapered section) adopts gas nitriding treatment, with a hardness of ≥800 HV, to enhance wear resistance and resist condensate droplet impact. A hard polyurethane foam insulation layer 10 wrapped around the outer wall of the steam passage 3 is provided between the steam passage 3 and the water collecting well 1, with a thickness of 80 mm. For straight pipe sections and conical pipe sections, hard polyurethane foam boards are used for assembly and coating; for irregularities such as flanges and valves, on-site spraying of foaming PUR can be used for filling, to ensure that the insulation layer is continuous and gap-free. Special adhesive should be used to seal the joints of the insulation layer to reduce the thermal bridge effect. The inner wall of the insulation layer 10 is provided with a salt protection layer, which is made of 0.5 mm thick galvanized steel plate and sprayed with a salt mist primer. The galvanized steel shell is fixed with self-tapping screws, and the joints are sealed with silicone glue.

[0048] Referring to Figure 2 and Figure 3As shown, in order to ensure that the heating of the leaching water is not affected by the external temperature difference, the heating module 2 is arranged at the bottom of the water collecting well 1, and specifically includes a heating cavity 21, a heating coil 22, high-temperature heat insulation cotton, and a storage battery. The heating cavity 21 is fixed at the bottom of the water collecting well 1 and is adapted to the shape of the water collecting well 1, and is a cylindrical shape, for containing the leaching water entering the water collecting well 1, and the drain pipe 11 and the blind pipe transport the collected leaching water to the heating cavity 21. The heating cavity 21 is made of 316 stainless steel, which has good magnetic conductivity to ensure the electromagnetic induction efficiency. The cavity body is 10 mm thick, and the inner wall is polished to reduce salt scale adhesion. The upper side of the heating cavity 21 is reserved with an outlet port adapted to the inlet end of the first conical pipeline 31. The heating coil 22 is a high-temperature mica wrapped glass fiber cable, which is wrapped around the outer sidewall of the heating cavity 21. The glass fiber and mica are combined to form a multi-layer insulation structure, which can withstand the eddy current heat effect of high-frequency current and avoid coil aging, leakage or short circuit due to high temperature. The coil is circular and closely surrounds the heating cavity 21, so that the eddy current in the heating cavity 21 is uniformly distributed, avoiding local overheating or dead angle. The high-temperature heat insulation cotton is wrapped outside the heating coil 22 to isolate the heating coil 22 and the well wall of the water collecting well 1, for reducing heat loss and environmental wear. The storage battery is arranged at the bottom of the heating cavity 21 and is electrically connected with the heating coil 22 and the power supply module 5 respectively, for storing the power generated by the power supply module 5 and supplying power to the heating coil 22. In use, the heating coil 22 uses high-frequency electromagnetic heating to directly generate eddy current heating inside the heating cavity 21, and the heat is concentrated inside the container, reducing the interference of external heat dissipation and environmental temperature on the heating efficiency, which is suitable for the climate with large diurnal temperature difference in Ningxia.

[0049] Referring to Figure 2 and Figure 4 As shown, further, in order to ensure that the water vapor can be smoothly cooled into condensed water, the condensing module 4 includes a ring-shaped rectifier 41, an eccentric reducer 42, and a heat exchange assembly.

[0050] The inlet of the annular rectifier 41 is communicated with the outlet end of the second conical pipe 33. After the water vapor enters the annular rectifier 41, it collides with the top and consumes kinetic energy. The flow rate of the gas flow is reduced, and the gas flow tends to be stable, while the salt particles are settled to the bottom due to gravity. The annular rectifier 41 is made of 316 stainless steel with a thickness of 10 mm, and the top is arc-shaped with a thickness of 10 mm. The inner wall of the annular rectifier 41 is sprayed with a WC-10Co-4Cr coating with a thickness of 100 μm and a hardness of ≥1100 HV to resist steam erosion. The inlet of the annular rectifier 41 is connected with the steam passage 3, and a plurality of eccentric reducers 42 are arranged in the lower middle part of the side wall of the annular rectifier 41 in a circular array. The eccentric reducers 42 are connected with the annular rectifier 41 near the second conical pipe 33. Each eccentric reducer 42 is connected with a condenser for cooling the steam distributed to the eccentric reducer 42 into condensed water. The size of the eccentric reducer 42 is reduced from Φ0.40 m to Φ0.25 m, and the eccentric distance is 400 mm. The eccentric reducer 42 is made of 316 stainless steel with a thickness of 5 mm, and the inner wall is electrolytically polished to Ra<0.8 μm, which can effectively reduce the attachment of salt scale. The outer wall of the annular rectifier 41 is wrapped with a hard polyurethane foam insulation layer with a thickness of 80 mm and a thermal conductivity of λ=0.040 W / m·K. A rubber shock pad with a thickness of 20 mm is installed at the bottom to reduce the noise and vibration caused by impact.

[0051] Referring to Figure 2 and Figure 5 As shown in the drawings, the heat exchange assembly includes a steam distribution pipe 43 and a plurality of heat exchange tube bundles 44. The steam distribution pipe 43 is inclinedly arranged, and the lower end of the inclined direction is communicated with one end of the eccentric reducer 42 away from the annular rectifier 41, and the other end is closed. The heat exchange tube bundle 44 includes a heat dissipation pipe 441 and a plurality of heat dissipation fins uniformly distributed on the outer side of the heat dissipation pipe 441. The heat dissipation pipe 441 is a flat thin-walled structure, and the surface of the heat dissipation fin is sprayed with a salt mist resistant coating. The heat dissipation pipe 441 is a flat welded thin-walled steel pipe, one end of which is connected with the steam distribution pipe 43, and the other end is connected with a water collecting pipe 442. The water collecting pipe 442 is used to communicate with the water storage tank 7 to realize the collection of condensed water. Preferably, in order to ensure the heat exchange efficiency and quality, two heat exchange tube bundles 44 are connected with each steam distribution pipe 43 to form an A-type heat exchange structure. The heat dissipation pipe 441 adopts a flat welded thin-walled steel pipe, and the outer surface of the heat dissipation pipe 441 is brazed with corrugated aluminum heat dissipation fins.

[0052] Further, in order to improve the heat exchange efficiency, the upper end of the second conical pipe 33 is further provided with a shell 8, the lower end of the shell 8 is sleeved on the outer wall of the water storage tank 7 and is fixedly connected with the water storage tank 7, and the lower side of the shell is preferably completely sealed by being fixed to the water storage tank 7. The upper end of the shell 8 is higher than the annular rectifier 41. The annular rectifier 41, the eccentric reducer 42, the steam distribution pipe 43 and the heat exchange pipe bundle 44 and other condensation modules 4 are all wrapped inside the shell 8. The shell 8 is provided with louvers 6 on the side wall, and the cold air flows into the heat exchange pipe bundle 44 and the heat dissipation fins in sequence. In this way, the cold air can be blown to the heat exchange pipe bundle 44 in a directional manner, and the cold air can flow uniformly, so that the heat exchange pipe bundle 44 can efficiently realize heat exchange.

[0053] Further, in order to improve the heat exchange efficiency, the upper end of the second conical pipe 33 is further provided with a shell 8, the lower end of the shell 8 is sleeved on the outer wall of the water storage tank 7 and is fixedly connected with the water storage tank 7, and the lower side of the shell is preferably completely sealed by being fixed to the water storage tank 7. The upper end of the shell 8 is higher than the annular rectifier 41. The annular rectifier 41, the eccentric reducer 42, the steam distribution pipe 43 and the heat exchange pipe bundle 44 and other condensation modules 4 are all wrapped inside the shell 8. The shell 8 is provided with louvers 6 on the side wall, and the cold air flows into the heat exchange pipe bundle 44 and the heat dissipation fins in sequence. In this way, the cold air can be blown to the heat exchange pipe bundle 44 in a directional manner, and the cold air can flow uniformly, so that the heat exchange pipe bundle 44 can efficiently realize heat exchange.

[0054] The water vapor is distributed to each heat exchange pipe bundle 44 by the annular rectifier 41. The water vapor is gradually cooled from top to bottom in the pipe by the heat dissipation fins, and the condensed water is collected in the water collecting pipe 442 at the bottom. After being filtered by the filter screen, the condensed water flows into the water storage tank 7 for standby use. The water storage tank 7 is directly irrigated by being deeply buried in the soil through the gravity pipe 12.

[0055] Specifically, in actual application, the heating module 2 and the steam passage 3 are arranged in the water collecting well 1. The overall height of the heating cavity 21 and the steam passage 3 is generally 6.45 m, of which the height of the heating cavity 21 is 1.85 m and the diameter is 1.50 m. The steam passage 3 is 4.60 m long. The first conical pipe 31 is 1.80 m high, and the diameter changes from 1.50 m to 0.80 m. The straight pipe 32 is 1.80 m high and the diameter is kept at 0.80 m. The second conical pipe 33 is 1.00 m high, and the diameter changes from 0.80 m to 1.00 m. The annular rectifier 41 is 1.00 m in diameter and is smoothly connected with the steam passage 3 by welding. The annular condenser is 1.00 m in diameter and is connected with the rectifier by the eccentric reducer 42 which is 0.40 m long. One end of the eccentric reducer 42 is connected with the annular rectifier 41 and has a diameter of 0.40 m, and the other end is connected with the annular condenser and has a diameter of 0.25 m.

[0056] Further, the solar power generation assembly includes multiple photovoltaic panels installed in a north-south direction and at an inclination. High-efficiency monocrystalline silicon photovoltaic panel assemblies are selected, which are resistant to sand and dust abrasion and can adapt to the climate in the northwest region, with a power attenuation lower than that of polycrystalline silicon photovoltaic panel assemblies under the same high-temperature environment. Eight 400W monocrystalline silicon assemblies are installed, each with an area of about 1.8m². The photovoltaic panels are installed in a north-south direction and at an inclination, with the inclination angle of the photovoltaic panels consistent with the latitude of the installation location, which is 38°, effectively reducing dust obstruction. The photovoltaic panels are arranged in multiple rows on the south side of the water collection well 1, with the spacing between the front row and the rear row preferably set at about 2.50m to avoid mutual shadow obstruction.

[0057] Further, the wind power generation assembly includes windmills and permanent magnet direct drive fans 9 for boosting and accelerating the wind force blowing towards the windmills at low wind speed. Three permanent magnet direct drive fans 9 with a rated power of 3kW are selected, each with a rotor diameter of about 3.00m, corresponding to a swept area A rotor ≈7.07m 2 that can start at low wind speed and adapt to the peak wind speed in Yinchuan at night; the permanent magnet motor eliminates the gear box structure, adopts a closed bearing and a dustproof coating, reduces sand and dust intrusion, and prolongs the service life. The three fans 9 are stably arranged on the north side of the water collection well 1 in a triangular array through independent supports.

[0058] The storage battery is a lithium iron phosphate battery with a capacity of about 5.0kWh and a rated voltage of 48V, which is arranged in the lower side compartment of the heating area of the water collection well 1 to reduce ground occupation and utilize the temperature insulation of the lower space of the water collection well 1.

[0059] Further, the water storage tank 7 is made of PVC corrosion-resistant plastic, with a thickness of 5mm, which is resistant to sand and dust abrasion and suitable for outdoor use with high cost performance. To avoid the influence of high-temperature heating, the outer wall should be covered with a heat insulation layer with a thickness of 20mm. The volume is determined according to the needs. A maintenance cover is provided on the top for easy cleaning and maintenance. A sewage valve and filter screen box are provided at the bottom to discharge foreign matter. A gravity water delivery channel is installed on the side wall of the water collection tank, which is made of polyethylene agricultural pipe with a diameter and volume determined according to the needs. The pipe is laid at a slope of 1%-2% to ensure smooth water flow. The pipe end is connected to a seepage irrigation ceramic pipe for underground drip irrigation. A louvered window 6 type air inlet is arranged above the water storage tank 7 and staggered with the ventilation structure of the water collection well 1, with an insect screen and dust gauze installed on the ventilation opening to prevent insect pests and debris and facilitate air exchange during condensation.

[0060] Theoretical design and analysis:

[0061] Theoretical calculation is performed based on 10kg of condensation per day, with the heating temperature increasing from the initial temperature of 20℃ (liquid state) to 100℃ (gas state).

[0062] Evaporation energy consumption calculation

[0063] The heating of the elution water from liquid to gaseous state mainly involves the transfer of heat and the conversion of energy: the energy Q is consumed to heat the water from the initial temperature T1 to the boiling point temperature T2 显 The energy Q is consumed to change the water from liquid to gaseous state 潜 While considering the partial loss Q in the process of heat transfer 损失 These energies are provided by the heating device E 输入 .

[0064] According to the principle of energy conservation, E 输入 The calculation formula is as follows:

[0065] .

[0066] In the formula: E 输入 Q is the electrical energy input per unit time of the heating module 2, kW·h. 显 Q is the heat required in the heating stage, kW·h. 潜 Q is the energy required in the phase change stage, kW·h. 损失 Q is the energy loss in the heating stage, kW·h.

[0067] Sensible heat calculation Q 显 : the energy consumed to heat to the boiling point,

[0068] .

[0069] In the formula: m is the mass of the brine, m = 10 kg. c is the specific heat capacity of the brine, c = 4.18 kJ / (kg·℃, ΔT is the temperature difference between the initial temperature and the boiling point, ΔT = 100℃-20℃. The calculation result is Q 显 = 3344kJ≈0.93kWh.

[0070] Latent heat calculation Qlatent: the energy requirement of phase change,

[0071] .

[0072] In the formula: m is the mass of the brine, m = 10 kg. L v is the latent heat of vaporization, L v ≈2256 kJ / kg. The calculation result is Q 潜 =22560kJ≈6.27kWh.

[0073] Energy loss Q 损失 : In the continuous process of heating-evaporation-condensation, the system may have various energy losses, mainly heat conduction loss Q loss,cond , water vapor loss Q loss,leak :

[0074] .

[0075] Heat conduction loss Q loss,cond Considering the heat loss of the elution water to the external environment during the whole heating condensation process, the Fourier law of steady-state heat conduction is adopted:

[0076] .

[0077] In the formula: k The thermal conductivity of the insulation material is k = 0.025 W / (m·K), the rigid polyurethane foam, A The total heat dissipation area of the device (m²) is about A= 25m 2 , Δ T The temperature difference between the inside and the environment (K) is Δ T= 25℃, The thickness of the insulation material (m) is ≈0.39m, t is the heating duration, s, which is calculated as 36000s according to 10h. The calculation result of Q loss,cond ≈5.86 kWh.

[0078] Water vapor loss Q loss,leak Considering that the steam carries tiny droplets that cannot be converted into usable water, the loss amount is proportional to the evaporation water amount:

[0079] .

[0080] In the formula: The water vapor emission coefficient is 0.05–0.15, and the calculation is performed by taking 0.1. m 蒸 The evaporation water mass is kg, L v The latent heat of vaporization is L v ≈2256 kJ / kg. The calculation result of Q loss,leak = 2256kJ≈0.63kWh.

[0081] The calculation result is: Q 损失 =Q loss,cond +Q loss,leak =6.49kWh,

[0082] E 输入1 = Q 显 +Q 潜 +Q 损 = 13.69kWh.

[0083] Electricity generation calculation

[0084] 1. High-frequency electromagnetic heater heat efficiency:

[0085] According to the sunshine and wind data of Yinchuan, Ningxia from 2019 to 2024 in China Statistical Yearbook, the power generation efficiency is analyzed. The daily sunshine duration in Yinchuan, Ningxia is about 7h, and the high-frequency electromagnetic heating system utilizes the eddy current heat effect: the alternating magnetic field (10kHz-30kHz) induces eddy current in the 316L stainless steel cavity, and the electric energy is converted into heat energy with an efficiency of =95%.

[0086] .

[0087] The calculation result is Q 输出 =14.41kWh.

[0088] Solar power generation principle and conversion efficiency

[0089] The formula for calculating the output power of photovoltaic components is:

[0090] .

[0091] In the formula: E pv is the output power of photovoltaic, kWh. pv is the photoelectric conversion efficiency, commonly used for single crystal silicon components 0.18~0.22, take 0.2. G is the total solar irradiance, W / m², the daily average in Ningxia area is about 700 W / m². A is the area of photovoltaic panel, m², is 12.6m 2 , t is the effective illumination time, h, take t =7h. The calculation result is E pv =14.11kWh.

[0092] Wind energy conversion formula and efficiency:

[0093] The average wind speed in Yinchuan area is between 3m / s and 4.5m / s, and the wind speed in some areas can reach 5.5m / s, which has the potential to deploy small wind turbines. The rated power formula:

[0094] .

[0095] In the formula: P is the rated power, W. p is the air density (1.2kg / m 3 ). A rotor is the corresponding swept area, 4.91m2 . v V=4m / s, the average daily wind speed in Ningxia is about 4m / s. C p Cp=0.3, the power coefficient is 0.3. The original power generation of a single fan per day is E wind =1.95kWh.

[0096] But due to the instability of wind speed, according to the actual utilization rate (85%), the daily power generation is: E wind-实际 =1.66kWh. The total daily power generation of three fans E wind-总实际 =4.98 kWh.

[0097] The total power generation capacity is:

[0098] The output of the photovoltaic system is about 14.11kWh for 7h. The output of the wind energy system is about 4.98kWh for 24h. Considering the loss of inverter and storage, the overall efficiency is 0.85:

[0099] .

[0100] According to the previous assumptions and analysis, the evaporation requires 9.82 kWh, and the system provides 10.91 kWh of power, meeting the goal of processing 10 kg per day.

[0101] Condensation calculation

[0102] According to the previous condenser structure layout, combined with engineering reference: the condensation efficiency of industrial air condenser under natural ventilation + fan auxiliary is generally 70%~85%, here η 冷凝 =80.0%, and considering the Ningxia environment, according to the "Ningxia Yanchi County Saline-alkali Soil Water Quality Report", the salt water concentration in Ningxia is C 盐 =3.5%.

[0103] The theoretical maximum evaporation water capacity is:

[0104] .

[0105] Then, the actual water capacity is:

[0106] .

[0107] In the formula, m 水实际 is the actual water capacity of the condensation module; m 水,max is the theoretical maximum evaporation water capacity; m 盐水 is the water capacity of the washing water; C 盐 is the salt water concentration in the washing water; η 冷凝 is the condensation efficiency.

[0108] Simulation analysis

[0109] CFX software is used to simulate the flow of water vapor in the steam passage 3 to prevent water vapor backflow or vortex from affecting the condensation effect. The steam pipe is divided by unstructured grid, the grid size is set to 0.015m, the grid size at the interface of each section is adjusted, and finally the number of grids is 12173090, and the grid quality is above 0.3.

[0110] Boundary condition setting: the fluid medium of the calculation domain is 100℃ ideal water vapor, the environmental pressure is 1atm, the turbulence model is k-ɛ turbulence model, and the heat transfer is solved by the internal energy form in the energy equation. Velocity import and average static pressure export are adopted. The simulation import velocity is set to 0.91m / s, the temperature is 100℃, the environmental temperature is 25℃, the thermal conductivity coefficient is set to λ=0.025W / (m·K), and the outlet relative pressure is 0Pa.

[0111] The main results obtained by simulation are as follows:

[0112] Referring to Figures 6 to 9 As shown in the figure, the elution water forms water vapor after heating and enters the first conical pipe 31, the inlet velocity is 0.91m / s, the gauge pressure is 9.51Pa, and the temperature is 373.15K. Due to the gradual reduction of the passage section, the water vapor accelerates obviously, the outlet velocity increases to 4.28m / s, the gauge pressure drops to 4.23Pa, and the temperature is 373.14K, which conforms to the gas flow characteristics under the Venturi effect, and the kinetic energy increases significantly.

[0113] Subsequently, the water vapor enters the straight pipe 32, the outlet velocity of the straight pipe 32 slightly decreases to 4.26m / s, the gauge pressure is 3.88Pa, and the temperature is 373.13K, which indicates that the gas flow remains stable and there is no back vortex disturbance. Then the water vapor enters the second conical pipe 33, and due to the gradual increase of the passage section, the water vapor velocity decreases, at the end of the second conical pipe 33, the water vapor velocity decreases to 2.51m / s, the gauge pressure rises to 6.89Pa, and the temperature is 373.10K, which conforms to the speed-pressure mutual transformation rule. At the top of the steam passage 3, due to the bending or local disturbance of the arc structure of the top wall of the annular fairing 41, the gauge pressure rises to 9.65Pa, and the temperature is 371.00K, which belongs to local perturbation phenomenon and does not affect the overall flow direction. Finally, through the eccentric reducer 42, it enters the steam distribution pipe 43, and due to the reduction of the pipe diameter of the eccentric reducer 42, the water vapor velocity increases to 5.13m / s, the temperature is 373.11K, and the pressure is consistent with the environment, which ensures that the water vapor can smoothly exchange heat in the heat exchange tube bundle 44 area.

[0114] From the temperature change trend, the water vapor from the inlet of the steam passage 3 gradually decreases from 373.14K to 373.11K at the outlet of the passage, without phase change, indicating that the heat preservation effect in the steam passage 3 is good, and the heat loss is controlled within a reasonable range. The water vapor is transmitted at a high flow rate, and has a large kinetic energy, which can effectively overcome the air resistance on the surface of the condenser, improve the disturbance degree of the heat transfer film, and thus improve the condensation efficiency.

[0115] In summary, the simulation verifies the rationality of the design of the "tapered-straight section-tapered" structure of the steam passage 3, and the water vapor flow has no obvious backflow or vortex in the entire steam passage 3, the velocity distribution is uniform, the pressure transition is smooth, and the temperature change is moderate, providing good input conditions for the subsequent condensation heat exchange process. The structure is expected to effectively improve the steam utilization rate and the system condensation efficiency in actual operation.

[0116] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A device for recycling saline-alkali soil leaching water, characterized in that, The utility model relates to a water collecting well (1) for collecting leaching water, a heating module (2) arranged at the bottom of the water collecting well (1) for heating the leaching water to make it evaporate into water vapor, a vapor channel (3) comprising a first conical pipe (31), a straight pipe (32) and a second conical pipe (33) arranged coaxially in sequence, the first conical pipe (31) and the second conical pipe (33) being respectively provided with an inlet end and an outlet end, the diameter of the inlet end of the first conical pipe (31) being larger than that of the outlet end, the diameter of the inlet end of the second conical pipe (33) being smaller than that of the outlet end, the outlet end of the first conical pipe (31) and the inlet end of the second conical pipe (33) being communicated through the straight pipe (32), the inlet end of the first conical pipe (31) being communicated with the output end of the heating module (2), a condensing module (4) connected to the outlet end of the second conical pipe (33) for cooling the water vapor to form condensed water, and a power supply module (5) comprising a solar power generation assembly and a wind power generation assembly for supplying power to the heating module (2). The condensing module (4) comprises: a ring-shaped rectifier (41) with its inlet communicated with the outlet end of the second conical pipe (33), a plurality of eccentric reducers (42) arranged in a circumferential array on the side of the ring-shaped rectifier (41), one end of each of the eccentric reducers (42) being communicated with the ring-shaped rectifier (41), a plurality of heat exchange assemblies corresponding to the plurality of eccentric reducers (42), each of the heat exchange assemblies being connected to the other end of the corresponding eccentric reducer (42) for cooling the steam distributed to the eccentric reducer (42) into condensed water. Each of the heat exchange assemblies comprises:

2. The device for recycling saline-alkali soil leaching water according to claim 1, characterized in that, a steam distribution pipe (43) arranged obliquely, the lower end of the oblique direction of the steam distribution pipe (43) being communicated with one end of the eccentric reducer (42) away from the ring-shaped rectifier (41), and the other end of the steam distribution pipe (43) being closed, a plurality of heat exchange pipe bundles (44), each of the heat exchange pipe bundles (44) comprising a heat dissipation pipe (441) and a plurality of heat dissipation fins uniformly distributed on the outer side of the wall of the heat dissipation pipe (441), the heat dissipation pipe (441) being of a flat thin-wall structure, one end of the heat dissipation pipe (441) being connected to the steam distribution pipe (43), and the other end of the heat dissipation pipe (441) being connected to a water collecting pipe (442), the water collecting pipe (442) being used to communicate with a water storage tank (7) to collect the condensed water, the water storage tank (7) being a ring-shaped cavity sleeved on the upper end of the second conical pipe (33). The upper end of the second conical pipe (33) is further provided with an outer shell (8), the lower end of the outer shell (8) being sleeved on the outer wall of the water storage tank (7) and being fixedly connected to the water storage tank (7), the upper end of the outer shell (8) being higher than the ring-shaped rectifier (41), the ring-shaped rectifier (41), the eccentric reducers (42), the steam distribution pipe (43) and the heat exchange pipe bundles (44) being all arranged in the outer shell (8), and a louver (6) being arranged on the side wall of the outer shell (8) to realize the inflow of cold air and the contact of the cold air with the heat exchange pipe bundles (44) and the heat dissipation fins. ​ 3. The device for recovering and utilizing leaching water in saline-alkali soil according to claim 2, characterized in that, ​ ​ ​ 4. The device for recycling saline-alkali soil leaching water according to claim 3, characterized in that, ​ 5. The device for recycling saline-alkali soil leaching water according to claim 4, characterized in that, A fan (9) is arranged between the top wall of the shell (8) and the annular rectifier (41), the air inlet of the fan (9) is located in the shell (8), the air outlet of the fan (9) penetrates the top wall of the shell (8) and is located outside the shell (8), and the fan (9) is used for discharging hot air in the shell (8).

6. The device for recycling saline-alkali soil leaching water according to claim 2, characterized in that, The top of the annular rectifier (41) is arc-shaped, and the connecting end of the eccentric reducer (42) is close to the second conical pipeline (33).

7. The device for recycling saline-alkali soil leaching water according to claim 1, characterized in that, The steam passage (3) is wrapped with a heat preservation layer (10) on the outside and is provided with a salt protection layer on the inside.

8. The device for recycling saline-alkali soil leaching water according to claim 1, characterized in that, The heating module (2) comprises: A heating cavity (21) is fixed at the bottom of the water collecting well (1), the upper end of the heating cavity (21) is provided with an opening, the opening of the heating cavity (21) is communicated with the inlet end of the first conical pipeline (31), and the heating cavity (21) is used for containing the leaching water entering the water collecting well (1); A heating coil (22) is arranged on the outer wall of the heating cavity (21); A storage battery is arranged at the bottom of the heating cavity (21) and is electrically connected with the heating coil (22) and the power supply module (5) respectively.

9. The device for recycling saline-alkali soil leaching water according to claim 8, characterized in that, The heating coil (22) is a high-temperature mica wrapped glass fiber cable.

10. The salt and alkali land leaching water recycling device according to claim 8, characterized in that, The outer side of the heating coil (22) is wrapped with high-temperature heat insulation cotton, so as to reduce heat loss.

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