Water sampling device from water-containing substances

Abstract

The present invention provides a water extraction device from water-containing substances that extracts water from water-containing substances and purifies the extracted water. [Solution] A water sampling device for a water-containing substance, comprising: a chamber for containing a water-containing substance including water and rock; means for generating water vapor by heating the water-containing substance in the chamber or by creating low-pressure conditions in the chamber; cooling means for generating water by cooling the water vapor; a turbidity removal filter through which the water from the cooling means passes; and a dissolved substance removal device for removing dissolved substances from the permeate water of the turbidity removal filter.

Description

Technical Field

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[0001] The present invention relates to a water extraction device from a hydrous substance. One aspect of the present invention relates to a device that extracts water from soil and earth containing water or frozen water (ice) and treats the extracted water. One aspect of the present invention relates to a water extraction device that extracts water contained as ice in regolith, which is sand covering the lunar surface and Martian surface, in order to secure water that is indispensable for humans to continue activities on the moon and Mars.

Background Art

[0002] It is considered that ice is widely distributed in regolith (sand covering the lunar surface) existing in the polar regions of the moon, especially in permanently shadowed regions, and the total amount is estimated to reach 6 billion tons. [[ID=​​​​​​​​​​​​​​To utilize the ice present alongside the regolith at the lunar poles as a water resource, it is necessary to excavate the lunar surface and extract the ice along with the regolith from underground. The lunar regolith contains many fine-grained components. JSC-1, a representative regolith simulator created to mimic the regolith collected during the Apollo program, contains nearly 10% fine particles smaller than 20 μm (Non-Patent Literature 2). Therefore, when ice is collected, fine regolith particles adhere to the ice, and when the ice is melted into liquid water, the regolith particles become mixed into the water as suspended matter. Furthermore, even when water or ice contained in the regolith is evaporated or sublimated to obtain water vapor, and this water vapor is collected to extract water, regolith particles are carried along with the water vapor, resulting in the mixing of regolith particles into the collected water.

[0007] Regolith-extracted water can be used as fuel for lunar landing craft and rovers by electrolyzing it to produce hydrogen and oxygen. However, impurities in the collected water can cause deterioration of the electrolysis equipment and a decrease in water electrolysis efficiency. Therefore, it is necessary to remove impurities from the collected water to produce pure water before supplying it to the electrolysis equipment.

[0008] Because regolith consists mainly of hard, sharp minerals composed of SiO2, there is a risk of wear, deterioration, or clogging of the electrolysis equipment when electrolyzing collected water to obtain hydrogen and oxygen. In addition, there is a risk of wear, deterioration, or clogging of the volatile substance removal equipment used to remove volatile substances such as methanol and formaldehyde from the collected water.

[0009] Furthermore, if a membrane separation device is used to remove regolith, problems such as membrane wear and damage caused by regolith particles may occur. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2011-140022 [Non-patent literature]

[0011] [Non-Patent Document 1] JB Holquist et al., “Analysis of a Cold Trap as a Purification Step for Lunar Water Processing”, ICES-2020-71 [Non-Patent Document 2] DS McKay et al., “JSC-1: A NEW LUNAR SOIL SIMULANT”, Engineering, Construction, and Operations in Space IV, American Society of Civil Engineers, pp. 857-866 (1994). [Overview of the project] [Problems that the invention aims to solve]

[0012] The present invention aims to provide a water extraction device from a water-containing substance that has the function of extracting water from the substance and purifying the extracted water. [Means for solving the problem]

[0013] The gist of the present invention's water extraction device from water-containing substances is as follows:

[0014] [1] A chamber containing a water-containing substance including water and rock, A means for generating water vapor by heating the water-containing substance in the chamber or by creating low-pressure conditions in the chamber, A cooling means for cooling the water vapor to produce water, A turbidity removal filter through which water from the cooling means passes, A device for removing dissolved substances from the permeate of the turbidity removal filter, and A device for collecting water from a water-containing substance.

[0015] [2] The water collection device from the hydrous substance according to [1], wherein the turbidity removal filter is a filter using a dead-end filtration method.

[0016] [3] The water collection device from the hydrous substance according to [1] or [2], wherein the turbidity removal filter is an external pressure type filter that allows water to flow from the outside of a tubular membrane or hollow fiber membrane.

[0017] [4] The water collection device from the hydrous substance according to [1], wherein the turbidity removal filter has a membrane with a nominal pore size of 0.01 to 2 μm.

[0018] [5] The water collection device from the hydrous substance according to [1], further comprising a return means for returning the non-permeate that did not pass through the turbidity removal filter to the chamber.

[0019] [6] The water collection device from the hydrous substance according to [1], wherein the hydrous substance is legolis.

[15]

[0020] [7] The water collection device from the hydrous substance according to [5], further comprising a particle collection means for collecting legolis particles in the water vapor sent from the chamber to the cooling means.

[0021] [8] The water collection device from the hydrous substance according to [7], wherein the particle collection means is a bag filter having a filter with an average pore size of 0.1 to 20 μm.

[0022] [9] The water collection device from the hydrous substance according to any one of [1] to [8], wherein the dissolved substance removal device includes one or more devices such as a RO membrane device, an electrically regenerative desalination device, and an electrodialysis device.

Advantages of the Invention

[0023] In the present invention's water extraction apparatus from a water-containing substance, water is vaporized from a water-containing substance containing liquid or solid water to generate water vapor, and this water vapor is cooled to produce water. Suspended solids are removed from this water using a turbidity removal filter, and dissolved substances are removed using a dissolved substance removal device. This allows for the acquisition of purified water.

[0024] In the cooling method, water vapor may condense into a liquid, or it may precipitate (coagulate) as solid ice. If ice is formed, it is melted to become liquid water.

[0025] Even if rock particles are present in the water from the cooling system, they are removed by the turbidity removal filter, thus preventing wear and blockage of the dissolved substance removal device. Passing the water vapor from the chamber through a particle collection device such as a bag filter or electrostatic precipitator further prevents particle contamination of the water.

[0026] The present invention's water extraction device from water-containing materials is suitable for extracting water from lunar and Martian regolith, but can also be used on Earth. [Brief explanation of the drawing]

[0027] [Figure 1] This is a diagram showing the configuration of a water sampling device from a water-containing substance according to an embodiment. [Figure 2] This is a diagram showing the configuration of a water sampling device from a water-containing substance according to an embodiment. [Figure 3] This is a diagram showing the configuration of a water sampling device from a water-containing substance according to an embodiment. [Figure 4] This is a cross-sectional view of a membrane separation device. [Modes for carrying out the invention]

[0028] The present invention will be described in more detail below.

[0029] The present invention relates to a water extraction device from a water-containing substance for the purpose of extracting and purifying water from a water-containing substance that contains water and other water-containing substances. The water in the water-containing substance may be in liquid or solid (ice) form.

[0030] The water-containing material is preferably rock containing water. The rock may be in the form of large chunks, small chunks, or particulates. In the case of particulates, the particle size according to the JIS sieve may be 0.2 mm or less, and particularly fine particles of 0.1 mm or less. The water-containing material may be a mixture of large chunks of rock and particulates. When particles of different particle sizes are mixed, the present invention can be suitably applied if it contains 5 wt% or more of particles of 0.020 mm or less and the average particle size (median diameter) is 0.020 to 0.2 mm. Furthermore, the present invention can be suitably applied if it contains 10 wt% or more of particles of 0.020 mm or less and the average particle size (median diameter) is 0.030 to 0.1 mm.

[0031] As a rock, (1) Igneous rocks formed by the cooling of magma, (2) Metamorphic rocks formed when existing rocks undergo recrystallization or intermineral reactions under physical or chemical conditions different from those at the time of their formation. (3) Sedimentary rocks formed when existing rocks are weathered or eroded, transported by water or other media, deposited, and solidified by the precipitation of chemically dissolved materials. (4) Altered rocks in which existing rocks have undergone material exchange through a solution, resulting in changes to their chemical composition, mineral composition, texture, or structure. Any of the above is acceptable.

[0032] The water content in the hydrated substance is preferably 0.1 to 50 wt%, particularly 1 to 20 wt%, but is not limited to this range.

[0033] As for the water-containing material, regolith is particularly suitable, but soil or sediment from around the world may also be used.

[0034] The water-containing material may be collected and processed while it is present on the surface of celestial bodies such as the Moon and Mars, as shown in Figures 1 and 2 below, or it may be collected and processed from there, as shown in Figure 3.

[0035] The following describes an embodiment of a water sampling device from a water-containing substance with reference to the drawings.

[0036] Figure 1 is a diagram showing the configuration of a water extraction device from a water-containing substance according to the first embodiment. In this embodiment, the water-containing substance is regolith present on the surface G of the Moon or Mars.

[0037] A chamber 1 with an open bottom is placed on surface G. Chamber 1 is made of a translucent material, at least partially, preferably mostly. Glass or synthetic resin are suitable as the translucent material.

[0038] At least a portion, preferably most or all, of the bottom surface of chamber 1 is open. In this embodiment, the entire bottom surface of chamber 1 is open. A sealing material such as rubber (not shown) is provided at the lower end of the side wall 1a of chamber 1, and the lower end of the side wall 1a is in airtight contact with the surface G.

[0039] The lower end of the side wall may be embedded in the surface G of the moon or other body of water, in which case the sealant may be omitted.

[0040] A steam outlet 1b is provided at the top of the chamber 1. The steam outlet 1b is connected to the fluid inlet chamber (primary side of the filter cloth 5b) 5a of the bag filter 5, which serves as a particle collection means, via piping 2, pump 3, and piping 4. The average pore size of the filter 5b of the bag filter 5 is preferably about 0.1 to 20 μm.

[0041] The filtration fluid chamber (secondary side of filter 5b) 5c of the bag filter 5 is connected to a cold trap 7 via piping 6. The cold trap 7 is preferably made of a stainless steel cylinder that cools and condenses or solidifies water vapor by the low ambient temperature, or is configured to condense or solidify water vapor on the outer surface of a metal pipe through which a refrigerant passes, but is not limited to these.

[0042] Furthermore, the cold trap 7 is equipped with a heater (not shown) for melting ice formed when water freezes. An electric heater or a solar concentrator can be used as the heater.

[0043] The lower part of the cold trap 7 is connected to the raw water tank 9 by piping 8. The water in the raw water tank 9 can be introduced into the primary chamber 12a of a dead-end filtration system turbidity removal filter 12 by pump 10 and piping 11. The water that has passed through the filtration element 12b of the turbidity removal filter 12 can be introduced into the turbidity removal treated water tank 14 via piping 13 from the secondary chamber 12c.

[0044] Furthermore, water from the turbidity removal water tank 14 is supplied to the secondary side of the turbidity removal filter 12 via the pump 30 and piping 31, allowing the turbidity removal filter 12 to be backwashed. Valves 13v and 31v are provided on the piping 13 and 31. Under normal conditions, valve 13v is open and valve 31v is closed. During backwashing, valve 13v is closed and valve 31v is open.

[0045] Backwash wastewater can be returned from the secondary chamber 12c to chamber 1 via piping 32. A valve 33 is provided in piping 32. This valve 33 is normally closed and is opened during backwashing. Alternatively, piping 32 may be connected to piping 11, allowing backwash wastewater to flow from piping 11 into piping 32.

[0046] The water in the turbidity-removed water tank 14 is sent to the RO (reverse osmosis) membrane device 18 by a high-pressure pump 16 and piping 17.

[0047] The permeate water that has passed through the RO membrane 18a of the RO membrane device 18 is sent via piping 19 to the electro-regenerative desalination unit (EDI) 20. The concentrated water that has not passed through the RO membrane 18a is returned to the chamber 1 via piping 21.

[0048] The electro-regenerative desalination apparatus 20 alternately forms a concentration chamber and a desalination chamber by arranging multiple anion exchange membranes and cation exchange membranes alternately, and fills the desalination chamber with a mixed resin of anion exchange resin and cation exchange resin.

[0049] The deionized water that has passed through the electrically regenerative desalination unit 20 is then passed through the piping 22 to the UV (ultraviolet) oxidation unit 23. In the UV oxidation unit 23, ultraviolet light emitted from a UV lamp decomposes organic substances (methanol, formaldehyde, etc.) in the water into organic acids and then CO2.

[0050] Water containing organic acids, etc., from the UV oxidation device 23 is passed through piping 24 to a mixed-bed resin device (mixed-bed ion exchange resin device) 25, where ions are adsorbed and removed, resulting in deionized water. The deionized water from the mixed-bed ion exchange resin device 25 is passed through piping 26 to a UF (ultrafiltration) membrane device 27, where fine particles of ion exchange resin are removed, and then the water is taken out as recovered water.

[0051] In a water extraction device configured in this way, when sunlight is irradiated into chamber 1, the regolith on the surface G of the moon or other body of water is heated, and water vapor is generated. Alternatively, sunlight may be focused using a concentrator and irradiated into chamber 1.

[0052] After most of the particles contained in this water vapor are removed by the bag filter 5, it is introduced into the cold trap 7 and becomes condensed water. Some of the condensed water may freeze, or the water vapor may directly precipitate as ice, but this ice is heated by an electric heater and melted into liquid water.

[0053] This water flows from the raw water tank 9 through a dead-end filtration system turbidity removal filter 12 into the turbidity removal treatment water tank 14.

[0054] The water in the turbidity-removed water tank 14 becomes permeate from which ionic components and suspended solids have been removed by the RO membrane device 18. This permeate is then desalinated in the electro-regenerative desalination device 20, and organic substances and ionic components are removed by the UV oxidation device 23 and the mixed-bed ion exchange resin device 25. Finally, it passes through the UF membrane device 27 to become recovered water (treated water).

[0055] According to the water collection device for water-containing substances in this embodiment, recovered water with a purity level from which fine particles, organic matter, and various ions have been sufficiently removed can be obtained. Because this recovered water is highly clean, even when supplied to an electrolysis device, problems such as wear, deterioration, and blockage of the electrolysis device are prevented.

[0056] In this embodiment, the backwash wastewater from the turbidity removal filter 12 and the concentrated water from the RO membrane device 18 are returned to the chamber 1, resulting in high water sampling efficiency.

[0057] As the filtration element 12b of the turbidity removal filter 12, an MF membrane or UF membrane with a nominal pore size of 0.01 to 2 μm can be used. In this case, it is preferable to supply the raw water from the raw water tank 9 to the turbidity removal filter 12 so that the permeate flux is 0.01 to 0.5 m / h.

[0058] When particles are trapped in the filtration element 12b of the turbidity removal filter 12 and the particle deposit layer (cake layer) thickens, the permeation flux of the turbidity removal filter 12 decreases, so backwashing is performed from the secondary side of the filtration element 12b. On the lunar surface and Mars, it is difficult to prepare air for backwashing, so air backwashing is omitted, and the permeation flux of the turbidity removal filter is restored by water backwashing alone. Water backwashing is preferably performed at a flow rate that results in a permeation flux of 0.1 to 0.5 m / h. The timing of backwashing can be periodic backwashing every 10 to 60 minutes, or backwashing can be performed when the supply pressure of the raw water is detected to have risen and reached a predetermined pressure.

[0059] To restore the permeate flux of the filter element 12b without performing air backwashing, a tubular filter, a hollow fiber filter, or a spring-type filter may be used as the filter element 12b. When the water-containing substance is regolith, the anorthite content is high in the mineral composition, and the particle detachment from the filter element is good, making it easy to restore the permeate flux without performing air backwashing. In particular, when the regolith particles contain 50 wt% or more anorthite, the detachment effect from the film by backwashing is high even without performing air backwashing.

[0060] For tubular filters, cylindrical porous filters with an outer diameter of 5 to 20 mm and a film thickness of 0.5 to 3 mm are preferred, and those made of fluororesins such as PTFE or PVDF, or ceramics such as alumina, SiC, or zeolite, can be suitably used. For hollow fiber filters, filters with multiple hollow fiber membranes having an outer diameter of 0.5 to 5 mm and a film thickness of 0.3 to 1 mm are preferred, and those made of fluororesins such as PTFE or PVDF can be suitably used. In tubular and hollow fiber filters, if raw water is flowed from the inside to the outside of the membrane, regolith particles accumulate on the inner surface of the membrane, making it easy for the membrane to become clogged. Therefore, it is preferable to flow the raw water from the outside to the inside of the membrane to capture the regolith particles on the outer surface of the membrane. For spring-type filters, those made of metal such as stainless steel or titanium are preferred. By flowing raw water from the outside to the inside of the spring in a spring-type filter, regolith particles can be captured on the outer surface of the spring. If regolith particles accumulate on the outside of the spring, the spring can be opened by flowing backwash water from the inside, allowing the accumulated layer of regolith particles to be detached. In the case of a spring-type filter, the mesh size of the filter is preferably 0.1 to 10 μm.

[0061] An example of the structure of a tubular filter is shown in Figure 4.

[0062] An external pressure-type cylindrical tubular filter 41 is arranged inside a cylindrical vessel 40. A raw water inlet 40a is provided at one end of the vessel 40, and piping 11 is connected to it via an attachment 48. A male thread 40b is provided on the outer circumference of the other end of the vessel 40, and a union nut type end cap 42 is attached by screwing it in.

[0063] The tube 43 is inserted into the vessel 40 through the axial hole of the end cap 42. The rear end of the tubular filter 41 is connected to the tip of the tube 43 via a coupler 44. The tip of the tubular filter 41 is sealed by a sealing block 45.

[0064] A protrusion 42b is provided on the end cap 42, projecting outward in the axial direction of the end cap 42. A male thread is engraved on the outer surface of the protrusion 42b. An O-ring 46 is positioned to seal the space between the inner surface of the end cap 42 and the outer surface of the tube 43. A nut member 47 for holding down the O-ring 46 is screwed onto the male thread on the outer surface of the protrusion 42b.

[0065] The rear end of tube 43 is connected to the pipe 13.

[0066] Referring to Figures 2 and 3, a water sampling device from a water-containing substance according to another embodiment will be described.

[0067] The water sampling apparatus from aqueous substances shown in Figure 2 is the same as the water sampling apparatus from aqueous substances shown in Figure 1, but with a sedimentation tank 50 added before the turbidity removal filter 12. Because the lunar surface has one-sixth the gravity of Earth, it is possible to separate regolith particles by sedimentation. By removing large-particle-sized regolith particles in the sedimentation tank 50 and then sending the water to the turbidity removal filter 12 via the pump 51 and piping 52, the load on the turbidity removal filter 12 can be reduced, and the frequency of backwashing of the filter and the deterioration of the filter can be suppressed.

[0068] While it is possible to install a pressurized flotation tank instead of a sedimentation tank, air is precious on the lunar surface, so it is preferable to install a sedimentation tank rather than a pressurized flotation tank that consumes pressurized air.

[0069] Since the regolith sludge that settles in the sedimentation tank 50 contains a large amount of water, it is preferable to return it to the chamber 1 via the piping 53 and recover the contained water by evaporating it again.

[0070] The other components of the water sampling apparatus from the water-containing material in Figure 2 are the same as those in Figure 1, and the same reference numerals indicate the same parts.

[0071] In Figures 1 and 2, the chamber 1 for evaporating or sublimating water in the regolith is of a type that heats regolith present on the surface of the Moon or other bodies of water using sunlight. However, as shown in Figure 3, the excavated regolith may be transferred to chamber 1A and heated with an electric heater 1h. Alternatively, instead of an electric heater, a heating gas may be supplied into chamber 1A to heat the water-containing material, or sunlight may be concentrated to heat it.

[0072] The other components in Figure 3 are the same as those in Figure 2, and the same reference numerals indicate the same parts.

[0073] In addition, in the water sampling apparatus from a water-containing substance shown in Figure 1, chamber 1A shown in Figure 3 may be installed instead of chamber 1.

[0074] In the above embodiment, the temperature inside Chamber 1 is raised to generate water vapor from the regolith. However, if an atmosphere exists, such as on Mars, the pressure inside Chamber 1 may be reduced to generate water vapor. [Examples]

[0075] [Example 1] 1 kg of regolith simulant (LHS-1, Exolith Lab, average particle size 51 μm (median diameter), 20 wt% of particles smaller than 20 μm, less than 1% of particles larger than 500 μm, mineral composition 58 wt% anorthite, 42 wt% other) adjusted to a water content of 20% was placed in a 3 L glass flask and heated while being aspirated with a vacuum pump. The regolith simulant was heated for 1 hour after reaching a temperature of 50°C. The pump exhaust was cooled with a cold trap, and condensed water (approximately 60 mL) was collected. The concentration of suspended solids (regolith particle concentration) in the condensed water was 4 g / L. This procedure was repeated 10 times, and a total of approximately 600 mL of condensed water was collected.

[0076] The condensed water was passed through a tubular filter shown in Figure 4 at a rate of 100 mL / min for approximately 10 minutes. The permeate from the tubular filter was sampled in two parts: 300 mL from the first half of the filtration process and 300 mL from the second half. The concentration of suspended solids was measured, and both the first and second halves showed concentrations lower than the lower limit of detection (5 mg / L).

[0077] Furthermore, after the 600 mL of water had been passed through, 100 mL of treated water was passed through the treated water outlet side at a rate of 100 mL / min for backwashing. As a result, the regolith particles that had been trapped on the outer surface of the tubular filter completely detached and flowed out from the raw water inlet side.

[0078] [Example 2] The test was conducted under the same conditions as in Example 1, except that an air filter (nominal pore size 10 μm) simulating a bag filter was placed between the container and the cold trap.

[0079] The concentration of suspended solids (regolith particles) in the condensate was 0.05 g / L, which was 1 / 80th of the concentration of suspended solids in the condensate of Example 1.

[0080] Furthermore, the concentration of suspended solids in the permeate from the tubular filter was below the detection limit (5 mg / L) in both the first and second halves of the experiment.

[0081] After the condensate was completely flushed, 100 mL of treated water was passed through the treated water outlet at a rate of 200 mL / min for backwashing. As a result, the regolith particles that had been trapped on the outer surface of the tubular filter detached and flowed out from the raw water inlet side. [Explanation of Symbols]

[0082] 1 Chamber 1a side wall 1b Steam outlet 5. Bug Filter 7 Cold trap 9. Raw water tank 12. Turbidity Removal Filter 12b Filtration element 14. Tank for treated turbidity-free water 18 RO membrane equipment 20 Electric regenerative desalination system 23 UV oxidation equipment 25 Mixed-bed ion exchange resin system 27 UF membrane equipment 40 Vessel 41 Tubular filter 42 End caps 42b protrusion 43 Tubes 44 Couplers 45 sealing blocks 46 O-rings

Claims

1. A chamber containing a water-containing substance including water and rock, A means for generating water vapor by heating the water-containing substance in the chamber or by creating low-pressure conditions in the chamber, A cooling means for cooling the water vapor to produce water, A turbidity removal filter through which water from the cooling means passes, A device for removing dissolved substances from the permeate of the turbidity removal filter, and A device for collecting water from a water-containing substance.

2. The apparatus for collecting water from water-containing substances according to claim 1, characterized in that the turbidity removal filter is a dead-end filtration type filter.

3. The apparatus for collecting water from a water-containing substance according to claim 1 or 2, characterized in that the turbidity removal filter is an external pressure type filter that flows water from the outside of a tubular membrane or hollow fiber membrane.

4. The device for collecting water from a water-containing substance according to claim 1, characterized in that the turbidity removal filter has a membrane with a nominal pore size of 0.01 to 2 μm.

5. The apparatus for collecting water from a water-containing substance according to claim 1, characterized in that it has a return means for returning any unpassed material that did not pass through the turbidity removal filter back to the chamber.

6. The apparatus for collecting water from a water-containing substance according to claim 1, characterized in that the water-containing substance is regolith.

7. The apparatus for collecting water from a water-containing substance according to claim 5, further comprising a particle collection means for collecting regolith particles in water vapor sent from the chamber to the cooling means.

8. The apparatus for collecting water from a water-containing substance according to claim 7, characterized in that the particle collection means is a bag filter having a filter with an average pore size of 0.1 to 20 μm.

9. The apparatus for collecting water from a water-containing substance according to any one of claims 1 to 8, characterized in that the dissolved substance removal apparatus includes one or more devices: an RO membrane apparatus, an electroregenerative desalination apparatus, and an electrodialysis apparatus.

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