JP2002239536A - Seawater desalination equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seawater desalting apparatus manufacturing fresh water from seawater with reduced energy consumption. SOLUTION: The seawater desalting apparatus is equipped with a first container capable of receiving seawater and capable of holding the space part of the container on seawater to a vacuum state, a second container having an adsorbent for adsorbing and desorbing steam arranged therein and equipped with a heating/cooling means for heating and cooling the adsorbent, a third container equipped with a condensing means for condensing steam, the first piping for allowing the first container to communicate with the second container and a vacuum means capable of evacuating at least the second container, The adsorbent is a porous body having pores with a center pore diameter of 0.1-50 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a seawater desalination apparatus, and more particularly, to a seawater desalination apparatus capable of desalinating seawater with a small amount of energy consumption.

[0002]

2. Description of the Related Art The demand for water is increasing worldwide due to the recent increase in population and the increase in industrial activities, and securing stable water resources has become an important issue. As a method for securing water resources, dams and groundwater are generally used, but seawater desalination using seawater as a raw material, which accounts for 90% or more of the earth's water, has recently attracted particular attention.

[0003] As a method of seawater desalination, a method using an evaporative seawater desalination apparatus that obtains freshwater by condensing water vapor generated by heating the collected seawater or introducing the collected seawater to a reverse osmosis membrane is used. A method using a reverse osmosis membrane type seawater desalination apparatus that obtains freshwater by pressing is known.

[0004]

However, in the case of using an evaporative seawater desalination apparatus, since seawater is heated at a high temperature, if there is a volatile component in seawater-existing substances other than salts, such a component is desalted. It gets mixed in. Therefore, there is a problem that a step of removing the water is required, and an installation place is limited to a place where the clean seawater with a small amount of volatile components can be collected.

[0005] Further, the evaporative seawater desalination apparatus requires a large amount of energy to evaporate seawater, and the reverse osmosis membrane type seawater desalination apparatus requires a large amount of mechanical energy for pressurization. However, any of the methods using these devices has a problem that the energy consumption during the production of fresh water is large.

The present invention has been made in view of the above prior art, and there is no need to heat seawater at a high temperature during the production of freshwater, and there is no need for much mechanical energy. It is an object of the present invention to provide a seawater desalination apparatus capable of producing a seawater desalination.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, the water vapor present under reduced pressure on the seawater introduced into the container was adsorbed with an adsorbent having a specific structure. After being adsorbed and desorbed, it is not necessary to heat the seawater at high temperature during the production of freshwater, and there is no need for much mechanical energy, and it is possible to produce freshwater from seawater with low energy consumption. Heading that
The present invention has been completed.

[0008] That is, the seawater desalination apparatus of the present invention is capable of introducing seawater into the inside thereof, and a first container capable of maintaining a space inside the container above the seawater in a reduced pressure state;
An adsorbent for adsorbing and desorbing water vapor is disposed therein, a second container provided with heating / cooling means for heating / cooling the adsorbent, and a third container provided with condensing means for condensing water vapor A first pipe connecting the first container and the second container, a second pipe connecting the second container and the third container, and reducing the pressure of at least the second container. And a pressure reducing means capable of reducing the pressure, wherein the adsorbent is a porous body having pores having a center pore diameter of 0.1 to 50 nm.

In the seawater desalination apparatus according to the present invention,
The first container is at atmospheric pressure (g weight / cm ^TwoA) seawater density
(G / cm^Three) And has a height equal to or greater than the value divided by
And was introduced into the container from below.
The space inside the container on the seawater was kept at reduced pressure by the weight of the seawater
Preferably, it is Further, the adsorbent,
Be a silica-based porous material having a center pore diameter of 2 to 50 nm.
Is preferred.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in more detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a first embodiment of the seawater desalination apparatus of the present invention. The seawater desalination apparatus 1 shown in FIG. 1 includes a seawater evaporating container (first container) 2, a vapor adsorption container (second container) 3, a vapor condensing container (third container) 4,
A first pipe 5 communicating the seawater evaporation container 2 and the steam adsorption container 3 is provided, and a second pipe 6 communicating the steam adsorption container 3 and the steam condensation container 4 is provided. Further, the seawater desalination apparatus 1 includes a third pipe 7 for connecting to the decompression means 8, and the first pipe 5, the second pipe 6, and the third pipe 7 respectively include A first valve 18, a second valve 19, and a third valve 20 are provided.

Seawater 11 is introduced into the seawater evaporating vessel 2,
The seawater 11 is supplied to a temperature controller 12 provided in the seawater evaporation container 2.
To maintain a constant temperature (for example, 25 ° C.). An adsorber 13 is provided inside the vapor adsorption container 3, and a heating / cooling unit 14 is connected to the adsorber 13, and the adsorbent 15 held inside the adsorber 13 is circulated, for example, with hot water or cold water. Can be heated and cooled.
The steam condensing container 4 includes a cooler 16 and a fresh water storage tank 17 for storing fresh water 21 condensed by the cooler 16. The adsorber 13 has a structure as shown in FIGS. 2 (a) and 2 (b). FIG. 2A shows the adsorber 13.
2B is an enlarged schematic view of a portion indicated by A of the adsorber 13 in FIG. 2A. FIG.
As shown in (b), an adsorbent 15 is held inside the adsorber 13, and fins 22 for improving the heating / cooling efficiency are provided.

By using such a seawater desalination apparatus 1, seawater can be desalinated by the method described below. That is, first, with the first valve 18, the second valve 19, and the third valve 20 opened,
, The pressure inside the seawater evaporation container 2, the vapor adsorption container 3, and the vapor condensation container 4 is reduced. here,
In order to prevent volatilization of the seawater 11 in the seawater evaporation container 2,
It is preferable to freeze the seawater 11 before driving the pressure reducing means 8.

Next, the first valve 18 and the second valve 1
9 and the third valve 20 are closed, and the seawater 11 inside the seawater evaporating container 2 is kept at normal temperature (for example, 25 ° C.) by the temperature controller 12.
, And water vapor is generated in the space inside the seawater evaporating container 2 above the seawater 11. Then the first valve 18
Is opened, the water vapor existing in the space inside the container of the seawater evaporation container 2 is guided to the vapor adsorption container 3 via the first pipe 5, and this water vapor is installed inside the vapor adsorption container 3. The adsorbent 15 in the adsorber 13 is adsorbed.
As for the movement of the water vapor, the adsorbent 15 reaches the saturated adsorption amount of the water vapor, and the pressure inside the vapor adsorption vessel 3 is reduced.
Continue until pressure equals internal pressure.

In the case of adsorbing water vapor on the adsorbent 15, it is preferable to maintain the temperature of the adsorbent 15 at room temperature (for example, 25 ° C.) by driving the heating / cooling means 14. Cooling means 1
It is preferable to carry out the process by flowing water or the like at room temperature through the adsorber 13 according to (4). After reducing the pressure inside the seawater evaporation container 2, the vapor adsorption container 3, and the vapor condensation container 4, the second valve 19 and the third valve 20 are closed, and the first valve 19 is closed.
By keeping the seawater 11 inside the seawater evaporation container 2 at a normal temperature with the valve 18 in the open state, steam may be generated inside the seawater evaporation container 2 and steam may be guided to the steam adsorption container 3.

After the adsorption of the water vapor by the adsorbent 15 is completed, the first valve 18 is closed and the second valve 19 is opened,
By driving the heating / cooling means 14 to heat the adsorbent 15 (for example, at 60 ° C.), the water vapor present inside the vapor adsorption container 3 and the water desorbed from the adsorbent 15 due to the heating become the second pipe. The fresh water 21 is led to the steam condensing container 4 via the condenser 6, condensed by the cooler 16, and stored in the fresh water storage tank 17.

After the fresh water 21 is stored in the fresh water storage layer 17, the second valve 19 is closed, the first valve 18 is opened, and the adsorbent 15 is returned to normal temperature in order to prevent the stored fresh water 21 from evaporating. In the same manner as described above, the water vapor generated from the seawater 11 is adsorbed by the adsorbent 15 and then desorbed, and the desorbed water (water vapor) is condensed in the steam condensing vessel 4 to obtain fresh water 2.
Get 1. Then, by repeating the above steps, a sufficient amount of fresh water can be obtained from seawater.

According to such a seawater desalination apparatus 1, it is not necessary to heat the seawater at a high temperature in order to obtain water vapor from the seawater by decompression near normal temperature, and generation of volatile components other than salts dissolved in the seawater. Is effectively prevented, and the required heat energy is overwhelmingly smaller than high-temperature heating, so that desalination of seawater can be performed with less energy. In addition, since the water vapor generated from the seawater is adsorbed by the adsorbent, the pressure in the space inside the container above the seawater is maintained, so that the water vapor is continuously generated from the seawater and the desalination of the seawater is efficiently performed. Be transformed into Furthermore, since the adsorption of water vapor to the adsorbent is caused by physical adsorption and / or chemical adsorption, fresh water can be taken out of seawater without applying mechanical energy from the outside, and the required energy is very small.

The seawater desalination apparatus of the present invention is not limited to the first embodiment described above, and other embodiments are possible. FIG. 3 is a schematic diagram showing a second embodiment of the seawater desalination apparatus of the present invention.

A seawater desalination apparatus 31 shown in FIG. 3 includes a seawater evaporating vessel (first vessel) 32, a steam adsorption vessel (second vessel) 33, a steam condensing vessel (third vessel) 34, A first pipe 35 that communicates the evaporation container 32 and the vapor adsorption container 33 and a second pipe 36 that communicates the vapor adsorption container 33 and the vapor condensation container 34 are provided. In addition, the seawater desalination apparatus 31 includes a third pipe 37 for connecting to the decompression means 8, and further includes a first pipe 35, a second pipe 36, and a third pipe 37, respectively. A first valve 38, a second valve 39, and a third valve 30 are provided.

The seawater evaporation container 32 has a height equal to or higher than the value obtained by dividing the atmospheric pressure by the density of the seawater 11 and is open downward, and the opening exists below the seawater surface 40. .
Further, the space 41 in the container above the seawater 11 can be kept at a reduced pressure by the weight of the seawater introduced into the seawater evaporation container 32 from below. The adsorber 13 is provided inside the vapor adsorption container 33, and the adsorber 13 is connected to a heating unit 51 and a cooling unit 52. Heating means 51
Can heat the adsorbent 15 held inside the adsorber 13 by, for example, circulating warm water heated by sunlight, and the cooling means 52 can be configured to circulate the adsorbent by, for example, circulating cold water cooled by seawater. 15 can be cooled.

By using such a seawater desalination apparatus 31, desalination of seawater can be performed by the method described below. That is, first, the first valve 38 is closed, and for example, the seawater evaporating container 32 is once filled with the seawater 11 in a state where the opening of the seawater evaporating container 32 is closed, and then the opening is opened, whereby the seawater evaporating container 32 is opened. Produces a so-called trickery vacuum. That is, the seawater level 42 in the container of the seawater 11 is lowered, and a space 41 in the container is generated on the seawater 11, and the space 41 in the container is filled with steam. The altitude difference (X in FIG. 3) between the seawater surface 42 in the container and the seawater surface 40 is a value obtained by dividing the atmospheric pressure (g weight / cm ² ) by the density of seawater (g / cm ³ ). For example, when the atmospheric pressure is 1 atm (1033 g weight / cm ² ) and the density of seawater is 1.033 (g / cm ³ ), the altitude difference is 1
0 m.

Next, by opening the second valve 39 and the third valve 30 and driving the pressure reducing means 8, the inside of the vapor adsorption container (second container) 33 and the vapor condensation container (third container) 34 To a reduced pressure. After that, the second valve 39 and the third valve 30 are closed, and the first valve 38 is opened, so that the steam present in the in-vessel space 41 of the seawater evaporation container 32 passes through the first pipe 35. The steam is led to the vapor adsorption container 33, and this water vapor is adsorbed by the adsorbent 1 in the adsorber 13 installed inside the vapor adsorption container 33.
5 is adsorbed. The movement of the water vapor is continued until the adsorbent 15 reaches the saturated adsorption amount of the water vapor and the pressure inside the vapor adsorption container 33 becomes equal to the pressure inside the vapor evaporation container 32.

When water vapor is adsorbed by the adsorbent 15, the cooling means 52 is driven to drive the adsorbent 1
5 at normal temperature (for example, cooling means 52 cooled with seawater).
(Medium water temperature). Before performing the adsorption of water vapor, the third valve 30 is opened, and the first valve 38 and the second valve 39 are closed.
, Only the inside of the vapor adsorption container 33 may be depressurized.

After the adsorption of the water vapor by the adsorbent 15 is completed, the first valve 38 and the third valve 30 are closed,
The second valve 39 is opened, and the heating means 51 is driven to heat the adsorbent 15 (for example, the heating means 51 heated by solar heat).
The water temperature present in the vapor adsorption container 33 and the water desorbed from the adsorbent 15 by heating are guided to the vapor condensation container 34 via the second pipe 36 and condensed. Then, the fresh water 21 is stored.

After the fresh water 21 is stored, the second valve 39 is closed and the first valve 38 is opened in order to prevent the stored fresh water 21 from evaporating, thereby adsorbing the water vapor present in the space 41 in the container. The adsorbed water vapor can be adsorbed by the agent 15, the adsorbed water vapor can be desorbed in the same manner as described above, and the water vapor can be further condensed in the vapor condensing container 34 to obtain fresh water 21. Then, by repeating the above steps, a sufficient amount of fresh water can be obtained from seawater.

According to such a seawater desalination apparatus 31,
The space 41 in the container can be reduced in pressure without providing a special decompression means in the seawater evaporation container 32. Further, since the seawater evaporation container 32 is opened downward, as the fresh water 21 is produced from the seawater 11, the seawater flows into the seawater evaporation container 32 from the opening, and the seawater surface 42 in the container is kept substantially constant. At the same time, a substantially constant amount of water vapor is supplied to the space 41 in the container. The adsorbent 15 can be cooled by seawater and heated by sunlight. Therefore, according to the seawater desalination apparatus 31, freshwater can be produced from seawater with a minimum energy consumption. Further, it is not necessary to heat the seawater at a high temperature to generate steam, and the generation of volatile components other than salts dissolved in the seawater is effectively prevented.

In the seawater desalination apparatus of the present invention described above, the center pore diameter is 0.1 to 50 n as the adsorbent.
It is characterized by using a porous body having m pores. Hereinafter, such a porous body will be described in detail.

First, the center pore diameter will be described. In the present invention, the central pore diameter refers to a curve (fine) obtained by plotting a value (dV / dD) obtained by differentiating the pore volume (V) of the porous body with the pore diameter (D) with respect to the pore diameter (D). Pore diameter distribution curve) at the maximum peak.

The pore size distribution curve can be obtained by the method described below. That is, the porous body is cooled to liquid nitrogen temperature (−196 ° C.), and nitrogen gas is introduced.
The adsorption amount is determined by the constant volume method, then the pressure of the nitrogen gas to be introduced is gradually increased, and the adsorption amount of the nitrogen gas with respect to each equilibrium pressure is plotted to obtain an adsorption isotherm. The pore size distribution curve is calculated using this adsorption isotherm by Cranston-Inklay
It can be determined by the method. In the present invention, if the center pore diameter of the porous body is less than 0.1 nm, desorption of water vapor becomes difficult, and if it exceeds 50 nm, the amount of adsorbed water vapor becomes insufficient, so that production of fresh water is realistic. Can not do at speed.

The porous body in the present invention may be any one having a pore having a center pore diameter of 0.1 to 50 nm, and its constituent components and shape are not particularly limited. The constituent components of the porous body include various metal oxides and composite oxides, and the porous body is preferably a silica-based porous body. Here, the silica-based porous body means a porous body made of only silica or a porous body made of a composite oxide containing silicon and a metal element other than silicon. The shape of the porous body may be, for example, a lump or a particle, but is preferably a particle because the contact area with water vapor can be increased.
Further, the pores may be independent pores in which the pores are not connected or continuous pores in which at least a part of the pores are connected, but the movement of water vapor inside the porous body is easy. For this reason, continuous pores are preferred.

Examples of the porous material in the present invention include zeolites having a central pore diameter of 0.1 to 1 nm and octahedral molecular sieves such as hollandite and titanic acid; sepiolite having a central pore diameter of about 1 nm; Viscous minerals such as palygorskite; central pore diameter of 2 to 50
and a silica-based porous material having a diameter of nm (so-called mesoporous silica). Among them, a silica-based porous body having a center pore diameter of 2 to 50 nm is particularly preferred as the porous body because of its particularly excellent water vapor adsorption and desorption characteristics.

In the present invention, the total pore volume
It is particularly preferable to use a silica-based porous material in which the ratio of the total volume of pores having a diameter within the range of ± 40% of the central pore diameter is 60% or more. Here, “the ratio of the total volume of pores having a diameter within the range of ± 40% of the central pore diameter to the total pore volume is 60% or more” means, for example, that the central pore diameter is 3. If it is 00 nm, ± 40 of this 3.00 nm
%, Ie, the sum of the pore volumes in the range of 1.80-4.20 nm, occupies 60% or more of the total pore volume. The porous body satisfying this condition has a very uniform pore diameter. The use of such a silica-based porous material having a very regular pore arrangement structure tends to further improve the adsorption and desorption characteristics of water vapor. The pore volume is calculated by a method of cooling a silica-based porous body to liquid nitrogen temperature and introducing nitrogen gas as described above (nitrogen adsorption method).

In the present invention, d is not less than 1 nm.
It is particularly preferable to use a silica-based porous material having an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to the value. When a peak appears in the X-ray diffraction pattern, it means that a periodic structure having a d value corresponding to the peak angle is present in the porous silica material. Therefore, 1 nm
The presence of one or more peaks at the diffraction angle corresponding to the above d value means that the pores are regularly arranged at intervals of 1 nm or more. By using such a silica-based porous material having a very regular pore arrangement structure, the adsorption and desorption characteristics of water vapor tend to be further improved.

The arrangement state of the pores (pore arrangement structure) in the silica-based porous material described above is not particularly limited. The silica-based porous body may have, for example, a hexagonal pore arrangement structure or a cubic or disordered pore arrangement structure. here,
The fact that the silica-based porous body has a hexagonal pore arrangement structure means that the arrangement of the pores of the silica-based porous body is a hexagonal structure. (S. Inagaki, et al., J. Chem. Soc.,
Chem. Commun., 680, 1993; S. Inagaki, et al., Bul
l. Chem. Soc. Jpn., 69, 1449; 1996, Q. Huo et a
l., Science, 268, 1324, 1995).

The fact that the silica-based porous material has a cubic pore arrangement structure means that the arrangement of the pores in the silica-based porous material is a cubic structure (JC Vartuli et al.,
Chem. Mater., 6, 2317, 1994; Q. Huo et al., Natur
e, 368, 317, 1994). The fact that the silica-based porous material has a disordered pore arrangement structure means that the arrangement of pores is irregular (PT Tanev et al., Sc
ience, 267, 865, 1995; SA Bagshaw et al., Scie
nce, 269, 1242, 1995; R. Ryoo et al., J. Phys. Che
m., 100, 17718, 1996).

When the silica-based porous material has a regular pore array structure such as hexagonal or cubic,
Not all of the pores need to be of these regular pore array structures. That is, the silica-based porous material may have both a regular pore arrangement structure such as hexagonal and cubic and a disordered irregular pore arrangement structure. However, it is preferable that 80% or more of all the pores have a regular pore arrangement structure such as hexagonal or cubic.

The method for producing the silica-based porous material is not particularly limited. For example, a production method using a liquid crystal structure (hereinafter referred to as “production method 1”) or a production method using a layered silicate (hereinafter referred to as “production method”). 2 ").

In production method 1, a silica raw material such as precipitated silica or water glass is added to an aqueous solution in which a surfactant (alkyltrimethylammonium salt) is dissolved and heated (for example, US Pat. No. 5,057,296). reference). In such a method, it is considered that the surfactant forms a cylindrical micelle in water, and silica is formed around the micelle, whereby a porous body is obtained. The alkyltrimethylammonium salt has a general formula of C _n H _{2n + 1
^{N + (CH 3) 3 ·}} X -. Has a chemical structure represented by (wherein, n integer, X is represents a counter anion such as halogen anion hereinafter also referred to as "ATMA". ).

Manufacturing method 2 is a method of forming a layer having ions between layers.
After ion exchange of silicate with ATMA, the layers are crosslinked.
(For example, JP-A-8-67578,
JP-A-8-277105). Manufacturing method 2
Further, kanemite (NaHSi) is used as a layered silicate.
_TwoO_Five・ 3H_TwoO), sodium disilicate crystals (α, β,
γ, δ-Na_TwoSi_TwoO_Five), Macatite (Na_TwoSi_FourO₉
・ 5H_TwoO), ialite (Na)_TwoSi₈O₁₇・ XH
_TwoO), magadiite (Na_TwoSi₁₄O₁₇・ XH
_TwoO), Kenyaite (Na_TwoSi₂₀O₄₁・ XH_TwoO) etc.
Can be used, furthermore, sepiolite, montmorri
Lonite, vermiculite, mica, kaolinite, su
Treatment of clay minerals such as mectite with acidic aqueous solution
Those from which elements other than those removed are also applicable.

In the production method 2, the pore diameter of the obtained porous silica material can be controlled by the length of the alkyl group in ATMA. ATMA
Is preferably a linear alkyl group, and the linear alkyl group preferably has 6 to 30 carbon atoms, and more preferably 8 to 22 carbon atoms. As the silica-based porous material in the present invention, those obtained by the production method 2 are preferable, and have a carbon number of 8, 10, 12, 14,
A silica-based porous material obtained by using ATMA having 16 or 18 linear alkyl groups is particularly preferred.

[0042]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

(Synthesis Example 1: Synthesis of Porous Silica Material) Dry water glass (SiO ₂ / Na ₂ O = 2.00) was calcined at 700 ° C. for 6 hours in air to obtain sodium disilicate (δ-Na). _Two
(Si ₂ O ₅ ). 50 g of this crystal is 500 m
L of water and stirred for 3 hours. Thereafter, the solid content was recovered by filtration to obtain kanemite. 50 g of the thus obtained kanemite was dispersed in 1000 mL of a 0.1 M aqueous solution of hexadecyltrimethylammonium chloride, and heated at 70 ° C. for 3 hours with stirring. The pH of the dispersion at the beginning of heating was 12.3. Then, while heating and stirring at 70 ° C., 2N hydrochloric acid was added, and the pH of the dispersion was adjusted.
Was reduced to 8.5. After further heating at 70 ° C. for 3 hours, it was allowed to cool to room temperature. The solid product was once filtered, dispersed again in 1000 mL of ion-exchanged water, and stirred. This filtration / dispersion / stirring was repeated 5 times and then air-dried. A sample obtained by air drying was heated in nitrogen at 450 ° C. for 3 hours, and then calcined in air at 550 ° C. for 6 hours to obtain a silica-based porous material (hereinafter, referred to as “FSM-16”).

The FSM-16 was subjected to powder X-ray diffraction, observation with a transmission electron microscope, and measurement of a nitrogen adsorption isotherm. X-ray powder diffraction was performed using a RAD-B
Scanning was performed at 2 degrees (2θ) / min using Kα as a radiation source. The slit width was 1 degree-0.3 mm-1 degree. JEOL JEM-200CX was used as a transmission electron microscope, and transmission electron micrographs were taken at an acceleration voltage of 200 kV. The nitrogen adsorption isotherm was determined by the constant volume method at the temperature of liquid nitrogen. The obtained X-ray diffraction pattern, transmission electron micrograph, and nitrogen adsorption isotherm are shown in FIGS. 4, 5, and 6, respectively.

In the X-ray diffraction pattern (FIG. 4), four peaks were observed in a low angle region of 10 degrees (2θ) or less. The respective d values are 3.7 nm, 2.1 nm, 1.
8 nm and 1.4 nm. FS from these peaks
M-16 was found to have a hexagonal pore array structure. In the transmission electron micrograph (FIG. 5), a honeycomb skeleton structure was observed, and the diameter of the pore was about 3 nm. The nitrogen adsorption isotherm (FIG. 6) is calculated using the relative vapor pressure (P /
P ₀ ) shows a sharply rising curve near 0.32, indicating the presence of uniform pores (mesopores).
The pore diameter distribution curve (FIG. 7) calculated from the nitrogen adsorption isotherm by the Cranston-Inklay method showed a sharp pore distribution centered on the central pore diameter of 2.7 nm. FIG. 7 also shows that the total volume of pores having a diameter within ± 30% of the central pore diameter (2.7 nm) occupies 80% of the total pore volume (ie, The proportion of the total volume of pores having a diameter within the range of ± 40% of the central pore diameter in the total pore volume was 60% or more.)

Example 1 Desalination of Model Seawater Using a seawater desalination apparatus having the same configuration as the seawater desalination apparatus 1 shown in FIG. 1, desalination of the model seawater by FSM-16 was performed. The configuration of the seawater desalination apparatus used is shown below. <Seawater evaporation container 2> Pyrex (registered trademark) glass flask having a capacity of 500 mL. <Temperature controller 12> 25 ° C. constant temperature water tank. <Vapor adsorption container 3> A 300 mL Pyrex glass container. <Adsorber 13> Adsorber made of aluminum (dimensions: 150
mm × 100 mm × 10 mm), and the FSM-16 obtained in Synthesis Example 1 was used as an adsorbent 15 in the space between the fins 22.
(22 g). <Heating / cooling means 14> This type heats and cools the adsorber 13 by circulating circulating water through the piping inside the adsorber 13, and can switch between 25 ° C (sea water temperature) and 60 ° C (hot water). Things. In addition, temperature sensors were installed at the inlet and outlet of the circulating water. <Cooler 16> Cooling water (25 ° C., seawater temperature) was passed through a Graham-type cooler (made of glass). <Freshwater storage tank 17> A test tube with a scale of 100 mL (made of glass). <Decompression means 7> Vacuum pump.

The operation procedure for desalination of the model seawater was as follows. That is, 300 mL of model seawater (a 4% by weight aqueous solution of sodium chloride) is placed in the seawater evaporation vessel 2,
The model seawater was frozen by cooling with liquid nitrogen. Next, while maintaining the frozen state of the model seawater, the first valve 18, the second valve 19, and the third valve 20 are opened, and the degree of vacuum is reduced to 0.1 m by the pressure reducing means 8.
After reducing the pressure to mHg or less, all valves were closed. Then, the temperature controller 12 was attached to the seawater evaporating vessel 2, and the frozen model seawater was thawed to maintain the liquid temperature at 25 ° C.

While the circulating water at 25 ° C. was circulated by the heating / cooling means 14, the first valve 18 was opened while the second valve 19 and the third valve 20 were kept closed.
Since the heat of adsorption was generated when the water vapor was adsorbed by the adsorbent 15, and the water temperature at the outlet side of the heating / cooling means 14 increased, the water was allowed to flow until the water temperature reached 25 ° C (about 300 seconds). When the temperature of the circulating water returns to 25 ° C., the first valve 18 is closed, the second valve 19 is opened, the temperature of the circulating water of the heating / cooling means 14 is switched to 60 ° C., and the circulating water is allowed to flow for about 300 seconds. Was. Next, the second valve 19 was closed, and the temperature of the circulating water of the heating / cooling means 14 was set to 25 ° C. The above was defined as one cycle, and this cycle was performed seven times, and the amount of fresh water generated in each cycle and the integrated amount of generated fresh water (total generated fresh water amount) were measured. The result is shown in FIG.

The total amount of generated fresh water in FIG. 8 increases with each cycle, indicating that fresh water was efficiently produced from the model seawater. In addition, during the production of fresh water, only energy was mainly consumed for driving the decompression means and the heating / cooling means, and it was found that fresh water could be produced from seawater with a small amount of energy consumption. Although the amount of fresh water generated in the first cycle in FIG. 8 is smaller than the amount generated in the subsequent cycles, this is consumed by the water vapor diffusion component because the seawater desalination apparatus is in a vacuum state. It is thought to be possible. From the second cycle onward, almost constant fresh water was produced, and the amount of fresh water generated per cycle from the second cycle to the sixth cycle was 12.3 mL.

When the first valve 18 is opened while the second valve 19 and the third valve 20 are kept closed, water vapor is adsorbed on the adsorbent 15 to generate heat of adsorption, which is cooled. In this case, water was circulated. In this case (second cycle), the time differential value of the temperature difference (ΔT) at the inlet and outlet of the circulating water was obtained and plotted (FIG. 9). FIG.
Thus, it was found that the heat generation based on the heat of adsorption stopped in about 100 seconds, and reached the adsorption equilibrium.

Further, when the temperature of the circulating water circulated by the heating / cooling means 14 was changed over, the fluctuation range of the relative vapor pressure (P / P ₀ ) inside the vapor adsorption vessel 3 was examined. It was found to fluctuate in the range of 15 to 1. P / P ₀ = 0.15 (circulating water temperature: 60 ° C., cooler 16 temperature: 25
℃) P / P ₀ = 0.95-1 (circulating water temperature: 25 ° C, temperature of seawater evaporation container 2: 25 ° C)

According to the water vapor adsorption isotherm of FSM-16 measured at 25 ° C. (FIG. 10), 1 g of FSM-1
For 6, 0.6 g of water vapor is adsorbed. In Example 1, since 22 g of FSM-16 was used, the amount of water vapor desorbed from FSM-16 per cycle was 0.6 ×
22 should be 13.2 g (13.2 mL), which is almost the same as the above measured value (12.3 mL).

From the heat release characteristics of the adsorber 13, it is expected that the seawater desalination apparatus used in Example 1 will exhibit sufficient seawater desalination performance by switching every 200 seconds. Therefore, the number of cycles per hour is 18, and the amount of fresh water produced per hour is 216 g. In addition, adsorbent 1
The amount of fresh water produced per g is 9.8 g / h. The above freshwater production amount is a sufficiently large value, and according to the present invention, a large amount of freshwater can be produced from seawater with a small energy consumption.

[0054]

As described above, according to the seawater desalination apparatus of the present invention, it is not necessary to heat seawater at a high temperature at the time of producing freshwater, and a large amount of mechanical energy is not required. It is possible to produce fresh water from seawater.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of a seawater desalination apparatus of the present invention.

2A is an enlarged view of an adsorber 13 in the seawater desalination apparatus of the present invention, and FIG. 2B is an enlarged view of a main part of the adsorber.

FIG. 3 is a schematic view showing a second embodiment of the seawater desalination apparatus of the present invention.

FIG. 4 is a diagram showing an X-ray diffraction pattern of FSM-16 obtained in Synthesis Example 1.

FIG. 5 is a transmission electron micrograph of FSM-16 obtained in Synthesis Example 1.

FIG. 6 is a diagram showing a nitrogen adsorption isotherm of FSM-16 obtained in Synthesis Example 1.

FIG. 7 is a view showing a pore size distribution curve of FSM-16 obtained in Synthesis Example 1.

FIG. 8 is a diagram showing the amount of fresh water generated in each cycle and the integrated amount of generated fresh water (total generated fresh water amount) in Example 1.

FIG. 9 is a diagram showing a time differential value of a temperature difference (ΔT) at the entrance and exit of the circulating water in the second cycle in the first embodiment.

FIG. 10 is a diagram showing a water vapor adsorption isotherm of FSM-16 (measuring temperature: 25 ° C.).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Seawater desalination apparatus, 2 ... Seawater evaporation container, 3 ... Steam adsorption container, 4 ... Steam condensing container, 5 ... First piping, 6 ... Second piping, 7 ... Third piping, 8 ... Decompression means , 11 ... sea water, 1
2 ... temperature controller, 13 ... adsorber, 14 ... heating / cooling means, 15 ... adsorbent, 16 ... cooler, 17 ... fresh water storage tank,
18 first valve, 19 second valve, 20 third
Valve 21, fresh water, 22 fin, 30 third valve, 31 seawater desalination device, 32 seawater evaporation vessel, 3
3 ... Steam adsorption container, 34 ... Steam condensing container, 35 ... First piping, 36 ... Second piping, 37 ... Third piping, 38 ... First valve, 39 ... Second valve, 40 ... Seawater Face, 41
... space portion in the container, 42 ... sea surface in the container, 51 ... heating means, 52 ... cooling means.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshiaki Fukushima 41-1, Oku-cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi F-term in Toyota Central R & D Laboratories Co., Ltd. 4D034 AA01 BA03 CA12 DA01 4D076 AA22 BA01 BC01 BC25 CD22 DA02 FA03 FA15 HA02 JA04 4G066 AA10D AA22B AA30A BA23 BA24 BA31 CA43 DA07 FA17 FA22 GA01

Claims (3)

[Claims] 1. A first container capable of introducing seawater therein and capable of keeping a space inside the container above the seawater in a reduced pressure state, and an adsorbent for adsorbing and desorbing water vapor. A second container provided with heating / cooling means for heating / cooling the adsorbent, a third container provided with condensing means for condensing water vapor, the first container and the second container
A first pipe communicating the second container, a second pipe communicating the second container and the third container, and a decompression unit capable of reducing the pressure of at least the second container. The desalination apparatus according to claim 1, wherein the adsorbent is a porous body having pores having a center pore diameter of 0.1 to 50 nm. 2. The method according to claim 1, wherein the first container has an atmospheric pressure (g weight / cm).
² ) has a height equal to or higher than a value obtained by dividing the density of seawater (g / cm ³ ) and is open downward, and the seawater introduced into the container from below has a weight above the seawater. The seawater desalination apparatus according to claim 1, wherein the space in the container is maintained at a reduced pressure. 3. The adsorbent has a central pore diameter of 2 to 50.
2. A silica-based porous material having a thickness of 1 nm.
Or the seawater desalination apparatus according to 2.