CN202080914U - Composite solar seawater desalting device - Google Patents

Abstract

The utility model discloses a compound solar seawater desalination device. The device body is composed of a water storage tank, a solar plate heat collector, a liquid distribution tank, a condensation evaporation pipe, a deflector, a heating surface, a compound parabolic surface concentrating heat collector, and a normal temperature evaporation It is composed of water tank, fresh water tank and hot water storage tank. The utility model absorbs solar energy through a flat plate heat collector and a compound parabolic concentrating heat collector, so that seawater undergoes falling film and film evaporation, collects steam and condenses to obtain fresh water, and completes the process of seawater desalination. The latent heat released by steam during condensation is used to generate secondary steam or increase the temperature of seawater to realize multi-effect utilization of solar energy. The utility model does not need auxiliary electric equipment, starts quickly, and has a high water production rate, and is especially suitable for use in sea islands, sea ships and remote areas.

Description

A composite solar desalination device

technical field

The utility model relates to a composite solar seawater desalination device, which belongs to the technical field of solar seawater desalination.

Background technique

The ocean covers 71% of the earth's surface area, with seawater reserves of about 1.37 billion cubic kilometers, accounting for 95% of the world's total water; terrestrial freshwater reserves of about 35 million cubic kilometers, accounting for 2.53% of the global water reserves. The fresh water used only accounts for 0.266% of the fresh water reserves, which is less than 7/100,000 of the earth's total water storage. my country has a long coastline, and many islands, coastal areas and inland brackish water areas have serious fresh water shortages. Therefore, the development of seawater desalination technology has far-reaching strategic significance to alleviate the current shortage of freshwater resources and the prominent contradiction between supply and demand.

Seawater desalination is the process of separating the salt and water in seawater (or brackish water), and finally obtaining fresh water and concentrated brine. The most commonly used technologies for seawater (or brackish water) desalination are multi-effect distillation, multi-stage flash evaporation, reverse osmosis, extraction and electrodialysis.

The multi-effect distillation method is to heat and distill seawater to generate steam. The steam generates fresh water and releases latent heat during the condensation process. The fresh water flows into the fresh water pool, and the latent heat is used to heat the seawater in the next effect and generate steam. Based on this, multi-effect utilization is carried out. Reduce heat consumption. In addition to consuming heat energy, this process also consumes a certain amount of electricity to drive water pumps and fans.

The multi-stage flash evaporation method is to introduce seawater heated to a certain temperature into several flash chambers whose pressure gradually decreases. Since the pressure of the flash chamber is lower than the saturated steam pressure corresponding to the seawater temperature, the seawater enters the flash chamber step by step and rapidly Vaporization, the salt concentration increases step by step, and the temperature decreases step by step. Since the heat comes from the temperature drop of the salt water itself, there is no special heating surface, which avoids the precipitation and scaling of inorganic salts until it is discharged. The steam at all levels is condensed to obtain fresh water. In addition to consuming heat energy, this process also consumes a large amount of electricity to drive vacuum pumps and water pumps.

The reverse osmosis method uses a reverse osmosis membrane to separate seawater and freshwater, and applies a sufficient pressure on the seawater side (exceeding the osmotic pressure of seawater) to reverse the water molecules in seawater to the freshwater side. This method does not consume heat energy, but it needs to consume a large amount of electricity to generate a large enough external pressure. In addition, the requirements for the reverse osmosis membrane are also very high.

Electrodialysis is a desalination process in which the potential difference is used as the driving force and the selective permeation of the ion exchange membrane is used to remove ions in water. Electrodeionization combines dialysis and ion exchange. The fresh water chamber of the electrodialyzer is filled with ion exchangers. Under the action of a DC electric field, the process of electrodialysis, ion exchange desalination and ion exchange continuous electrical regeneration is realized. Electrodeionization is not used for desalination of brackish water, but mainly for the production of high-purity water. This method does not consume heat energy, but needs to introduce electricity.

Freezing is a process in which seawater is frozen below the freezing point, and freshwater is frozen, separated, and then melted into freshwater. The freezing method has the utilization of natural ice method and artificial freezing method. But the technology is not yet mature.

Traditional seawater desalination technology requires high investment and high energy consumption. According to statistics, a device that produces 13 million tons of desalinated water per day needs to consume 130 million tons of crude oil every year. In addition to the cost of this fuel, the resulting greenhouse effect, air pollution and other issues cannot be ignored. As far as our country is concerned, remote villages, deserts, isolated islands and other areas in the northwest are seriously short of power, and it is impossible to build traditional seawater (or brackish water) desalination devices. Solar desalination technology is an effective way to solve the problem of fresh water shortage in these areas, and has broad application prospects.

The current solar desalination technology usually integrates solar heat collection and seawater distillation and desalination, which is easy to operate and maintain, but the device occupies a large area, slow to start, and low water production per unit area, which is greatly affected by the region and climate conditions. The daily fresh water production is low, which seriously restricts the application and promotion of its technology.

Contents of the invention

The purpose of the utility model is to overcome the deficiencies of the existing solar seawater desalination technology, and provide a composite solar seawater desalination device which does not need auxiliary electric equipment, starts quickly, and has a high water production rate.

The composite solar seawater desalination device includes a drain valve, a hot water storage tank, a steam distribution tank, a condensation evaporation pipe, a liquid distribution tank, a solar panel collector, a first drain valve, a second drain valve, a water storage tank, and a room temperature evaporator , the first fresh water valve, the water inlet valve, the fresh water tank, the second fresh water valve, the drain valve, the compound parabolic concentrating heat collector, and the deflector; the normal temperature evaporator includes a fresh water collection tank, hydrophilic fibers, and the fresh water tank includes steam circulation Hole, condensing horizontal plate, second vent hole, condensing vertical wall, steam distribution box includes deflector, first vent hole, heating surface; water storage tank, first water discharge valve, flat plate collector, liquid distribution tank are connected in sequence , the water storage tank is connected to the outside world through the second water discharge valve. There is a liquid distribution hole at the bottom of the liquid distribution tank. There is a condensation evaporation pipe under the liquid distribution tank. The condensation evaporation pipe is arranged horizontally with a slope. The lower end of the condensing and evaporating pipe is connected to the fresh water tank, the steam distribution box is connected to the hot water storage tank through a deflector, a compound parabolic concentrating heat collector is installed under the heating surface, and the condensation vertical is between the fresh water tank and the normal temperature evaporator. The bottom of the room temperature evaporator is provided with a drain valve, the middle and upper part of the room temperature evaporator is provided with a water inlet valve, and the lower end of the top surface of the room temperature evaporator is provided with a first fresh water valve, and the room temperature evaporator passes through the first fresh water valve, The water inlet valve and the drain valve are connected with the outside world, the fresh water tank is connected with the outside world through the second fresh water valve at the bottom, and the hot water storage tank is connected with the outside world through the drain valve at the bottom.

The angle of inclination of the deflector and the heating surface is 5-30°. The lower side of the heating surface is coated with a selective absorption coating. The inclination angle of the condensing and evaporating tubes is 5-30°, and there are several rows and rows arranged in parallel. Hydrophilic fibers are arranged on the condensation vertical wall and the condensation horizontal plate. The gap between the deflector and the fresh water tank is 0.5-5mm.

Compared with the prior art, the utility model has the following advantages:

1. The utility model does not introduce conventional energy sources such as electricity at all, and is especially suitable for remote areas, deserts, islands and other areas lacking electricity.

2. The evaporation involved in the utility model is all thin-film evaporation, the heat capacity of the thin film is small, the required heat source temperature is low, the evaporation speed is fast, and the water production is high.

3. In the utility model, the evaporation and condensation are carried out in different spaces, which speeds up the rate of evaporation and condensation, and most of the heat transfer involved is phase change heat transfer, the required heat exchange area is small, and the device is compact.

4. According to the difference of steam temperature, the utility model uses the latent heat of steam condensation to promote the evaporation of liquid film, which not only makes the heat transfer effect better, increases the condensation rate, but also improves the water production rate, and realizes the cascade and repeated utilization of energy .

5. The structure of the utility model is simple, the sealing requirements are not high, and the installation, disassembly and washing, and replacement are convenient.

Description of drawings

Fig. 1 is the structural representation of composite solar seawater desalination device;

Fig. 2 is a left side sectional view of the normal temperature evaporator of the present utility model;

Fig. 3 is the left side sectional view of the fresh water tank of the present utility model;

Fig. 4 is a right side sectional view of the steam distribution box of the present invention

Fig. 5 is a left side sectional view of the steam distribution box of the present invention;

Fig. 6 is a structural schematic diagram of the deflector of the present invention;

In the figure: drain valve 1, hot water storage tank 2, deflector 3, steam distribution box 4, condensing evaporation pipe 5, first vent hole 6, liquid distribution tank 7, solar plate collector 8, first water release Valve 9, second water discharge valve 10, water storage tank 11, steam flow hole 12, condensation horizontal plate 13, second ventilation hole 14, normal temperature evaporator 15, condensation vertical wall 16, fresh water collection tank 17, first fresh water valve 18, Hydrophilic fiber 19, water inlet valve 20, fresh water tank 21, heating surface 22, second fresh water valve 23, drain valve 24, compound parabolic concentrating heat collector 25, flow deflector 26.

Detailed ways

As shown in Figure 1, the composite solar seawater desalination device includes a drain valve 1, a hot water storage tank 2, a steam distribution box 4, a condensation evaporation pipe 5, a liquid distribution tank 7, a solar plate collector 8, and a first water discharge valve 9. Second water discharge valve 10, water storage tank 11, room temperature evaporator 15, first fresh water valve 18, water inlet valve 20, fresh water tank 21, second fresh water valve 23, drain valve 24, compound parabolic concentrator 25 , deflector 26; Normal temperature evaporator 15 comprises fresh water collecting tank 17, hydrophilic fiber 19, and fresh water tank 21 comprises steam circulation hole 12, condensing horizontal plate 13, the second ventilation hole 14, condensing vertical wall 16, steam distribution box 4 Including deflector 3, first ventilation hole 6, heating surface 22; water storage tank 11, first water discharge valve 9, flat plate heat collector 8, liquid distribution tank 7 are connected in sequence, water storage tank 11 is connected with the second water discharge valve 10 Connected to the outside world, there is a liquid distribution hole at the bottom of the liquid distribution tank 7, and a condensing and evaporating pipe 5 is arranged under the liquid distribution tank 7. The condensing and evaporating pipe 5 is arranged horizontally and has a slope. The lower end of the evaporation pipe 5 is connected to the fresh water tank 21, the steam distribution tank is connected to the hot water storage tank 2 through the deflector 26, a compound parabolic concentrating heat collector 25 is arranged under the heating surface 22, and the fresh water tank 21 is connected to the normal temperature evaporator 15 There are condensing vertical walls 16 and condensing horizontal plates 13 between them. A drain valve 24 is provided at the bottom of the normal temperature evaporator 15. A water inlet valve 20 is provided at the middle and upper part of the normal temperature evaporator 15. A first fresh water valve is provided at the lower end of the top surface of the normal temperature evaporator 15. The valve 18 and the normal temperature evaporator 15 are respectively connected to the outside world through the first fresh water valve 18, the water inlet valve 20 and the drain valve 24. The fresh water tank 21 is connected to the outside world through the second fresh water valve 23 at the bottom, and the hot water storage tank 2 is connected to the outside world through the bottom water valve 23. The drain valve 1 is connected with the outside world.

The inclination angle of the deflector 3 and the heating surface 22 is 5-30°. The lower side of the heating surface 22 is coated with a selective absorption coating. The inclination angle of the condensing and evaporating pipes 5 is 5-30°, and there are several rows and rows arranged in parallel. Hydrophilic fibers 19 are arranged on the condensation vertical wall 16 and the condensation horizontal plate 13 . The gap between the deflector 3 and the fresh water tank 21 is 0.5-5mm. The first vent hole 6 and the second vent hole 14 are equipped with top covers with good sealing performance, which can be opened and closed freely.

The composite solar seawater desalination method is as follows: the solar panel heat collector 8 is used to absorb solar energy to heat the seawater flowing through the flat plate heat collector 8 from the water storage tank 11, and preheat the seawater to hot seawater with a temperature of 50-60°C. The hot sea water enters the liquid distribution tank 7, flows down from the liquid distribution hole at the bottom of the liquid distribution tank 7, and drops on the condensing and evaporating tube 5, part of the hot sea water forms a seawater film on the condensing and evaporating tube 5, and the remaining hot sea water Under the action, it is separated from the condensing and evaporating tube 5, drips onto the deflector 3, and is introduced into the heating surface 22 through the deflector 3. The deflector 3 and the heating surface 22 have an inclination. A layer of seawater film is formed on the upper surface, and the lower side of the heating surface 22 is coated with a selective absorption coating, which absorbs the sunlight gathered by the compound parabolic concentrator 25 and converts it into heat, which heats the seawater film on the heating surface 22, and the seawater film absorbs The heat evaporates rapidly, and the unevaporated seawater flows into the hot water storage tank 2, and the generated steam enters the condensation and evaporation pipe 5 through the steam distribution box 4, and the steam condenses into fresh water in the condensation and evaporation pipe 5, enters the fresh water tank 21, and is transferred from the second fresh water The valve 23 leads out, and the latent heat of condensation released when the steam in the condensing and evaporating pipe 5 is condensed is absorbed by the seawater film outside the condensing and evaporating pipe 5, which promotes partial evaporation of the seawater film to generate secondary steam, which enters the fresh water tank 21 through the steam flow hole 12 , condenses into fresh water on the condensing horizontal plate 13 and the condensing vertical wall 16 between the fresh water tank 21 and the normal temperature evaporator 15, and the latent heat of condensation is transferred into the normal temperature evaporator 15 through the condensing vertical wall 16 and the condensing horizontal plate 13. The wall 16 and the condensing horizontal plate 13 are provided with hydrophilic fibers 19. Under the action of the hydrophilic fibers 19, the seawater at the bottom of the normal temperature evaporator 15 forms a layer of seawater film on the condensing vertical wall 16 and the condensing horizontal plate 13. The film absorbs the latent heat of condensation released from the secondary steam condensation and quickly evaporates to generate tertiary steam. The tertiary steam condenses into fresh water on the top surface of the normal temperature evaporator 15, enters the fresh water collection tank 17, and is drawn out by the first fresh water valve 18 to store hot water. The hot sea water in the tank 2 is transferred to the water storage tank 11 every 2-5 hours.

Working process of the present utility model:

First, fill the water storage tank with seawater at normal temperature, add seawater at normal temperature to the evaporator at normal temperature, open the drain valve connected to the flat plate collector, heat the water into the flat plate collector to a temperature of 50-60°C, and then enter the liquid distribution tank. It flows out from the liquid distribution hole at the bottom of the liquid distribution tank and drips onto the condensing and evaporating tube. Part of the hot sea water forms a uniform film, and the hot sea water that has not formed a film continues to fall to the deflector, and is guided by the deflector through the deflector and fresh water. The narrow gap between the tanks flows to the heating surface to form a layer of seawater film. The seawater film absorbs the heat of the heating surface and evaporates quickly to generate primary steam. The unevaporated seawater flows into the hot water storage tank through the deflector to store hot water. The salt water in the tank is transferred to the water storage tank every 2-5 hours, and the primary steam generated flows through the steam distribution tank and then enters the condensing and evaporating tube, where falling film condensation occurs in the condensing and evaporating tube, and the latent heat of condensation is condensed by the seawater outside the evaporating tube The film absorbs and forms falling film evaporation. The fresh water condensed in the condensing and evaporating tube slides down the tube under the action of gravity until it enters the fresh water tank. The secondary steam generated outside the condensing and evaporating tube enters the fresh water tank through the steam flow hole, respectively Condensation occurs on the vertical wall and the condensing horizontal plate to form fresh water, and the latent heat is transferred to the room temperature evaporator. The latent heat of condensation of the secondary steam quickly evaporates to form tertiary steam. The steam rises to the top surface to condense into fresh water and then slides down to the fresh water collection tank. It is drawn out through the first fresh water valve. The temperature of the fresh water in the fresh water tank is higher than that of the seawater in the normal temperature evaporator , Fresh water transfers heat to sea water, increasing its temperature and speeding up the evaporation rate. The room temperature evaporator replenishes water every 2-5 hours.

Example 1:

The initial room temperature seawater capacity of the water storage tank is 1 ton, the total lighting area of the collector is 4m ² , the concentration ratio of the compound parabolic concentrator is 3, the efficiency of the flat plate collector is 60%, and the outer diameter of the condensing and evaporating copper tube is 25.4mm. The length is 200mm, the number of tubes is 9, arranged in a row, the inclination angle is 15°, the condensation area of the vertical wall of the fresh water tank is 200×800mm ² , the condensation area of the horizontal plate is 100×800mm ² , the material is stainless steel, the wall thickness is 2mm, and the hydrophilic fiber is covered in the condensation area. On the horizontal plate and the condensing vertical wall, the seawater inlet temperature is 20°C. After being preheated to 50°C by the solar panel collector, it enters the liquid distribution tank. Replenish water every hour, transfer the hot seawater in the hot water tank to the water storage tank every 5 hours, control the flow rate of seawater to 20kg/h, and the daily fresh water production can reach 15-20kg/m ² .

Example 2:

The initial normal-temperature seawater capacity of the water storage tank is 1 ton, the total lighting area of the collector is 5m ² , the concentration ratio of the compound parabolic concentrating collector is 4, the efficiency of the flat plate collector is 65%, the outer diameter of the condensing and evaporating copper tube is 25.4mm, and the tube length 200mm, 12 tubes, arranged in a row, with an inclination angle of 15°, the condensation area of the vertical wall of the fresh water tank is 200×800mm ² , the condensation area of the horizontal plate is 100×800mm ² , the material is stainless steel, the wall thickness is 2mm, and the hydrophilic fiber is covered in the condensation horizontal On the plate and the condensing vertical wall, the seawater inlet temperature is 20°C. After being preheated to 60°C by the solar panel collector, it enters the liquid distribution tank. The initial temperature of the seawater in the normal temperature evaporator is 20°C, and the initial liquid level height is 50mm. Water replenishment once, the hot seawater in the hot water storage tank is transferred to the water storage tank every 6 hours, the seawater flow rate is controlled at 20kg/h, and the daily fresh water production can reach 18-24kg/m ² .

Claims (6)

1. a combined solar energy sea water desalinating plant is characterized in that comprising water escape valve (1), heat storage water tank (2), steam distribution case (4), condensation evaporation pipe (5), cloth liquid case (7), plate solar collector (8), first water drain valve (9), second water drain valve (10), water tank (11), constant-temperature evaporation device (15), the first fresh water valve (18), water intaking valve (20), fresh-water tank (21), the second fresh water valve (23), water discharge valve (24), compound parabolic concentrator collector (25), director (26); Constant-temperature evaporation device (15) comprises fresh water receiving tank (17), hydrophilic fibers (19), fresh-water tank (21) comprises vapour stream through hole (12), condensation transverse slat (13), second ventilating pit (14), the perpendicular wall (16) of condensation, and steam distribution case (4) comprises flow deflector (3), first ventilating pit (6), hot face (22); Water tank (11), first water drain valve (9), flat plate collector (8), cloth liquid case (7) links to each other in turn, water tank (11) links to each other with the external world through second water drain valve (10), cloth liquid case (7) bottom is provided with liquid distributing hole, cloth liquid case (7) below is provided with condensation evaporation pipe (5), condensation evaporation pipe (5) lateral arrangement, obliquity is arranged, condensation evaporation pipe (5) is high-end to link to each other with steam distribution case (4), condensation evaporation pipe (5) low side links to each other with fresh-water tank (21), the steam distribution case links to each other with heat storage water tank (2) through director (26), hot face (22) below is provided with compound parabolic concentrator collector (25), be perpendicular wall (16) of condensation and condensation transverse slat (13) between fresh-water tank (21) and the constant-temperature evaporation device (15), constant-temperature evaporation device (15) bottom is provided with water discharge valve (24), constant-temperature evaporation device (15) middle and upper part is provided with water intaking valve (20), constant-temperature evaporation device (15) end face low side is provided with the first fresh water valve (18), constant-temperature evaporation device (15) is respectively through the first fresh water valve (18), water intaking valve (20), water discharge valve (24) links to each other with the external world, fresh-water tank (21) links to each other with the external world through the second fresh water valve (23) of bottom, and heat storage water tank (2) links to each other with the external world through the water escape valve (1) of bottom.

2. a kind of combined solar energy sea water desalinating plant according to claim 1 is characterized in that described flow deflector (3), hot face (22) angle of inclination are 5-30 °.

3. a kind of combined solar energy sea water desalinating plant according to claim 1 is characterized in that described hot face (22) downside scribbles coating for selective absorption.

4. a kind of combined solar energy sea water desalinating plant according to claim 1 is characterized in that described condensation evaporation pipe (5) angle of inclination is 5-30 °, and plurality of rows is arranged, some row, and in-line arrangement is arranged.

5. a kind of combined solar energy sea water desalinating plant according to claim 1 is characterized in that described condensation is erected on wall (16), the condensation transverse slat (13) to be furnished with hydrophilic fibers (19).

6. a kind of combined solar energy sea water desalinating plant according to claim 1 is characterized in that the slit between described flow deflector (3) and the fresh-water tank (21) is 0.5-5mm.

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