CN-121970557-A - Multistage solar distillation desalting device and application thereof in saline-alkali soil treatment

Abstract

The invention discloses a multistage solar distillation desalting device and application thereof in saline-alkali soil treatment, the device comprises seven stages, each stage is respectively provided with a heating layer, a capillary layer, an air gap layer and a condensing layer from top to bottom, each stage is stacked from top to bottom, a heat-dissipation aluminum grid is arranged at the lower part of the seventh stage, the device has a multistage structure with optimized heat insulation performance so as to reduce energy loss and realize latent heat recovery, thereby improving heat efficiency, fresh water produced by condensation is collected to irrigate soil so as to achieve water recycling, a water absorption channel is optimized, the capillary layer with a U-shaped structure is designed so as to realize continuous water supply of thick soil and large-scale soil, and the device has high application potential in large-scale saline soil repair and saline-alkali soil treatment.

Inventors

• XUE GUOBIN
• TANG JIEBIN
• LI JUNHUI
• ZHANG YAFANG
• YANG GUANGCHUN
• ZHOU WEIJIA

Assignees

• 济南大学

Dates

Publication Date

20260505

Application Date

20260212

Claims (8)

1. 1. A multistage solar distillation desalting device is characterized by comprising seven stages, wherein each stage comprises a heating layer (1), a capillary layer (2), an air gap layer (3) and a condensing layer (4) from top to bottom, each stage is stacked from top to bottom, a heat dissipation aluminum grid is arranged at the lower part of the seventh stage, the heating layer (1) is used for converting solar energy into heat energy and heating evaporating salt solution, one end of the capillary layer (2) is inserted into soil and absorbs the salt solution from the soil, the air gap layer (3) is of a gap structure with the periphery formed by a heat insulation foam frame, and the condensing layer (4) comprises a non-woven fabric (41) and an aluminum sheet (42) from top to bottom.
2. 2. The multi-stage solar distillation desalination device of claim 1, wherein the heating layer is made of a low emissivity photo-thermal material for absorbing sunlight and converting it into heat.
3. 3. The multi-stage solar distillation desalination device of claim 2, wherein the photo-thermal material is a blue film.
4. 4. The multistage solar distillation desalination device according to claim 1, wherein the capillary layer (2) is a non-woven fabric, and the non-woven fabric has capillary pores therein, and the capillary pores ensure water absorption capacity and water transport capacity of the non-woven fabric.
5. 5. The multistage solar distillation desalination device according to claim 1, wherein the non-woven fabric is divided into a left part, a middle part and a right part, the left part of the non-woven fabric is inserted into soil, the middle part is placed right below the heating layer as an evaporation area to receive heat of the heating layer, the salt solution is evaporated to generate water vapor, the right part is protruded outside the distillation device to contact air, and the salt solution is evaporated at the protruded end.
6. 6. The multistage solar distillation desalination device according to claim 1, wherein the capillary layer (2) is designed as a U-shaped structure (21), the left side of the U-shaped structure (21) is sealed with polytetrafluoroethylene film, and the right side of the U-shaped structure (21) is exposed to the soil.
7. 7. The multistage solar distillation desalination device according to claim 1, wherein the non-woven fabric (41) is T-shaped for flowing condensed liquid water back to the soil.
8. 8. Use of the multistage solar distillation desalination device of claims 1-7 in saline-alkali soil remediation.

Description

Multistage solar distillation desalting device and application thereof in saline-alkali soil treatment Technical Field The invention belongs to the technical field of solar devices, and particularly relates to a multistage solar distillation desalting device and application thereof in saline-alkali soil treatment. Background Soil salinization constitutes a global ecological challenge with an impact range of about 10 hundred million hectares. The salinized soil seriously hinders plant growth by forming a high-permeability environment, interferes with the water absorption process of plants, and finally leads to growth inhibition and crop yield reduction. For this reason, researchers have developed various saline soil remediation strategies. Irrigation leaching is the most widely used method, and soluble salt is leached down from the root zone to deep soil or discharged out of the field by injecting a large amount of fresh water, so that the salt in the soil is reduced. However, irrigation requires a lot of fresh water, and saline-alkali soil tends to be water-starved, which aggravates the pressure of water-land relationship. In addition, the discharge of salt-containing wastewater produced during irrigation leaching constitutes a significant and unavoidable environmental challenge. In recent years, interfacial solar evaporators have shown great potential in the field of soil remediation. The technology converts sunlight into heat energy through the photo-thermal material and enables the heat energy to be concentrated at an evaporation interface, so that high photo-thermal conversion efficiency is ensured. When the method is applied to the repair of the saline soil, the water absorbing material conveys the saline water in the soil to the evaporation interface through capillary action. As the water evaporates, the salt in the salinized soil is enriched in the evaporator, thereby reducing the soil salt concentration. Compared with the traditional irrigation leaching method, the interface solar evaporation technology can repair the salinized land in situ with high efficiency, and meanwhile, the fresh water consumption is remarkably reduced. However, the high latent heat of evaporation inherent to the thermal evaporation process limits the evaporation rate even under high light-to-heat conversion efficiency conditions. Because water is the primary medium of salt transport, the limited evaporation rate directly reduces the salt flux in the soil. Continuous evaporation of water into the atmosphere requires a continuous fresh water input to maintain the balance of the system, resulting in a significant increase in fresh water consumption. Furthermore, as an emerging technology, its scalability and adaptability have not been quantitatively assessed under realistic conditions-these conditions include spatially varying soil thickness and real-scale restoration requirements. Disclosure of Invention The invention aims to provide a multistage solar distillation desalting device and application thereof in saline-alkali soil treatment, and for a system for restoring evaporated saline-alkali soil by utilizing the sun, the design consideration should include the following points of 1, stable evaporation desalting. And 2, recycling water, and reducing fresh water consumption. 3, high evaporation desalting rate. 4, can be effectively applied to actual soil desalination, especially thick-layer soil and large-scale soil. In order to achieve the above object, the technical scheme of the present invention is as follows: A multistage solar distillation desalting device comprises seven stages, wherein each stage comprises a heating layer, a capillary layer, an air gap layer and a condensing layer from top to bottom, each stage is stacked from top to bottom, a heat dissipation aluminum grid is arranged at the lower part of the seven stages at the bottommost layer, and a blue film is selected to convert solar energy into heat energy for heating evaporating salt solution in order to reduce radiation heat loss of the heating layer by adopting a low-emissivity photo-thermal material as the heating layer. The capillary layer is non-woven fabrics, and a plurality of capillary holes are formed in the non-woven fabrics, and the capillary holes ensure the water absorption capacity and the water transportation capacity of cotton cloth. The left part of the non-woven fabric is inserted into the soil, and the saline solution is sucked from the soil. The middle part is used as an evaporation area and is arranged at the right lower part of the heating layer to receive the heat of the heating layer, and the evaporating salt solution generates water vapor. The right part of the non-woven fabric stretches out of the distillation device, contacts air, and the saline solution crystallizes at the stretching end. The air gap layer is a gap around which the heat-insulating foam frame is formed, and water vapor generated in the evaporation area is transporte