Forward osmosis membrane module

Abstract

To provide a forward osmosis membrane module capable of exhibiting osmosis capacity based on the constitution of a spiral type forward osmosis membrane module.SOLUTION: A forward osmosis membrane module includes: a case 2; a plurality of membrane leaves 5 which is housed in the case and causes a forward osmosis phenomenon; and a main conduit 3 in communication with a salt water flow path which is a gap between the plurality of membrane leaves; wherein salt water is supplied from the main conduit to the salt water flow path, each membrane leaf has an open pair of first and second ends perpendicular to the main conduit, fresh water is supplied from the first end to the inside of the membrane leaf, the fresh water supplied to the inside of the membrane leaf moves in a first direction from the first end toward the second end, and the salt water supplied to the salt water flow path includes, the fresh water which moves in the second direction directed to the fourth end on the reverse side from the third end that is the end on the main conduit side, and unpermeated water is discharged from the second end, and mixed water is discharged from the fourth end, and the right osmosis arises between the fresh water moving in the first direction in the membrane leaf and the salt water which moves in the second direction in a salt water flow path, and mixed water and unpermeated water occur.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a forward osmosis membrane module capable of producing mixed water with high efficiency. [Background technology]

[0002] In recent years, shortages of water for daily use (especially water for drinking and eating) have become an issue not only in Japan but in many countries around the world. One reason for this is that the supply of water for daily use is not keeping up with the global population increase (mainly in developing countries). Furthermore, there is an increasing influx of population from rural areas to urban areas in many countries, which is disrupting the balance of the supply of water for daily use relative to the population in urban areas, which already have few freshwater sources such as rivers and lakes. In addition, desertification caused by global warming and the concentration of heavy rain in certain areas can make it difficult to store fresh water suitable for daily use. Furthermore, the construction of dams on rivers can be made difficult due to growing awareness of environmental issues.

[0003] For these reasons, water shortages for domestic use are becoming more serious in Japan and other countries around the world. A shortage of water for domestic use is a problem that can sometimes give rise to internal conflicts or disputes with neighboring countries.

[0004] In the above-mentioned environment, desalination plants for desalinating saltwater are being installed in coastal areas and other locations to obtain fresh water from saltwater. In Japan, too, saltwater desalination plants are increasingly being installed in relatively quiet inland seas such as coasts of urban areas and bays where water shortages are likely to occur. Saltwater desalination plants take in saltwater from inland seas and generate fresh water using components such as reverse osmosis membranes and forward osmosis membranes. The generated fresh water is used as water for daily life.

[0005] On the other hand, as desalination plants are used to turn saltwater into freshwater, the disposal of the resulting concentrated saltwater is an issue, because disposing of concentrated saltwater on land or in the sea would lead to environmental destruction.

[0006] In addition to concentrated saltwater, saltwater, including seawater, is found in various places on Earth, and there is a demand for its utilization. In particular, concentrated saltwater and seawater produced by saltwater desalination plants are often found in places where natural freshwater is difficult to obtain, such as areas where desertification is progressing.

[0007] As one way of utilizing such concentrated saltwater or seawater, a power generation system using a forward osmosis membrane is being considered. Concentrated saltwater or seawater and fresh water are supplied to the forward osmosis membrane. If treated water from a sewage treatment system or the like is used as the fresh water, the environmental load can be reduced.

[0008] In the forward osmosis membrane, water permeates from the fresh water passage to the salt water passage. This increases the amount of water in the salt water passage, resulting in an increased amount of mixed water. This increased amount of mixed water can be used to rotate a turbine to generate electricity.

[0009] At this time, the torque of the turbine leads to power generation. The torque is generated by the integral of the pressure of the mixed water and the increase in water content, and it is necessary to efficiently increase the water content in the forward osmosis membrane.

[0010] The mixed water used to rotate the turbine has a lower salinity because it receives moisture from the freshwater flow path through a forward osmosis membrane, so the mixed water after rotating the turbine will not pose an environmental burden even if it is released into the ocean.

[0011] There is an existing technology that uses hollow fibers as a forward osmosis membrane. Hollow fibers are a technology that has been used for a long time, and have a proven track record, including ease of manufacturing. A forward osmosis membrane is made up of hollow fibers, which are thin tubes with small diameters, densely packed in a pipe. Fresh water is supplied into the hollow fibers, and salt water is supplied between the hollow fibers. The fresh water permeates the outside of the hollow fibers due to the forward osmosis phenomenon, increasing the amount of salt water.

[0012] However, hollow fiber technology has already reached a considerable level, and further improvements are unlikely to be expected, because there is a limit to the permeability per unit area of ​​hollow fibers, and improvements in the number and density of hollow fibers are approaching their limits.

[0013] As mentioned above, to use a forward osmosis membrane for power generation, it is necessary to efficiently generate the forward osmosis phenomenon and increase the water volume, because the integral of the increased water volume and pressure becomes the energy that rotates the turbine.

[0014] In this situation, forward osmosis membranes that utilize a spiral type instead of a hollow fiber type have been proposed (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0015] [Patent Document 1] JP 2014-023986 A [Patent Document 2] JP 2014-023985 A Summary of the Invention [Problem to be solved by the invention]

[0016] Patent Document 1 discloses a spiral-type forward osmosis membrane element comprising a membrane leaf 23 having an internal flow path extending from a first opening 26A to a second opening 26B, and a central tube 31 around which the membrane leaf 23 is wound and having a supply hole 31A communicating with the first opening 26A and a recovery hole 31B communicating with the second opening 26B, the inside of the central tube 31 being partitioned so that an inflow region 3A communicating with the supply hole 31A and an outflow region 3B communicating with the recovery hole 31B each form a flow path extending continuously in the axial direction of the central tube 31 from one end to the other end of the central tube 3. The element is a spiral-type forward osmosis membrane element in which a liquid supplied to the inflow region 3A is discharged to the outside without flowing through the internal flow path 26 multiple times.

[0017] Patent Document 2 discloses a spiral-type forward osmosis membrane element that includes a membrane leaf 23, a central tube 3 around which the membrane leaf 23 is wound, and a plurality of partition walls (31, 32) provided inside the central tube 3. The membrane leaf 23 is provided with a plurality of internal flow paths 26 that are bent in parallel from a first opening 26A toward a second opening 26B. The central tube 3 has an inlet 33 at one end and an outlet 34 at the other end, and is provided with a supply hole 35 communicating with the first opening 26A and a recovery hole 36 communicating with the second opening 26B. The end partition wall 32 located closest to the outlet 34 blocks the inside of the central tube 3, and the partition walls 32 other than the end partition wall are provided with through holes 38.

[0018] In a spiral-type forward osmosis membrane module, a bag-shaped forward osmosis membrane with a wide area is folded and housed in a circular manner inside the module body. Each forward osmosis membrane has a wide area, and fresh water is supplied to the inside of the bag-shaped forward osmosis membrane, and salt water is supplied to the gaps (outside) between the multiple bag-shaped forward osmosis membranes. The permeation capacity per unit area is higher than that of the hollow fiber type, and the permeation capacity from fresh water to salt water is greater. As a result, the increased water volume is greater.

[0019] On the other hand, when using forward osmosis membranes in the power generation system described above, it is necessary to continuously supply saltwater and freshwater, and to discharge both the mixed water containing the increased amount of water and the non-permeated water (the freshwater that does not completely permeate into the saltwater side). There are cases where it is not possible or desirable to forward osmosis all of the supplied freshwater into the saltwater side, and non-permeated water remains. This non-permeated water needs to be discharged, and two outlets are required. For this reason, two inlets and two outlets are required.

[0020] In the case of a hollow fiber type which is a thin tube having both ends, it is easy to provide two inlets and two outlets by the both ends of the hollow fiber type and the both ends of the gaps between the hollow fibers.

[0021] On the other hand, since the spiral-type forward osmosis membrane module is a bag-shaped forward osmosis membrane, it has only one inlet and two outlets, making it difficult to use in a power generation system.

[0022] Patent Documents 1 and 2 are technologies that realize two inlets and two outlets. In both Patent Documents 1 and 2, a partition plate is provided inside a bag-shaped forward osmosis membrane, and one side of a main pipe that supplies moisture to the inside of the bag-shaped forward osmosis membrane is set as an inlet, and the other as an outlet. The partition plate causes moisture to move around inside the return path, creating a water flow that returns moisture from the inlet to the outlet of the same main pipe. This water flow realizes two inlets and outlets, with the same main pipe as the inlet and outlet (the gap between the bag-shaped forward osmosis membranes becomes another set of inlets and outlets).

[0023] However, in both Patent Documents 1 and 2, a partition plate is used to create a water flow to the main pipe, which causes problems such as increased labor in manufacturing, labor required to ensure the quality of the product, and defects in strength and usability.

[0024] In addition, because the water needs to flow through the partition, the water flow becomes less smooth, and stagnation occurs inside the bag. This stagnation and lack of smoothness results in the impediment of the permeation capacity. This is because the permeation capacity of the membrane leaf is reduced in areas where there is no stagnation or smoothness caused by the partition. This is a problem in that the permeation capacity cannot be exerted as a whole. In other words, the partition makes it difficult for water to reach the entire inside of the membrane leaf, making it difficult to utilize the forward osmosis phenomenon that utilizes the entire membrane of the membrane leaf. As a result, the problem occurs that the amount of water that can undergo forward osmosis is low compared to the capacity.

[0025] There is also the problem that the permeability of the membrane leaf varies from place to place, which can lead to deterioration of the membrane leaf.

[0026] As a result, the conventional techniques such as those disclosed in Patent Documents 1 and 2 have a problem in that they are unable to exhibit the permeation capacity of the spiral-type forward osmosis membrane module.

[0027] An object of the present invention is to solve these problems and to provide a forward osmosis membrane module that can exhibit a sufficient permeation capacity based on the configuration of a spiral-type forward osmosis membrane module. [Means for solving the problem]

[0028] In view of the above problems, the forward osmosis membrane module of the present invention comprises a case and A plurality of membrane leaves housed in the case to cause a forward osmosis phenomenon; A main pipe communicating with a saltwater flow path which is a gap between the plurality of membrane leaves, Salt water is supplied to the salt water flow path from the main pipe, Each of the plurality of membrane leaves has a first end and a second end, which are a pair of ends perpendicular to the main pipe, open, and fresh water is supplied into the membrane leaf from the first end, The fresh water supplied to the inside of the membrane reef moves in a first direction from the first end toward the second end, The salt water supplied to the salt water flow path moves in a second direction from a third end portion, which is an end portion on the main pipe side, toward a fourth end portion on the opposite side to the third end portion, Unpermeated water is discharged from the second end, The mixed water is discharged from the fourth end. A forward osmosis phenomenon occurs between the fresh water moving in the first direction inside the membrane reef and the salt water moving in the second direction in the salt water flow path, generating the mixed water and the non-permeated water. Effect of the Invention

[0029] In the forward osmosis membrane module of the present invention, since no partitions are provided inside the membrane leaf, the water flow inside the membrane leaf is prevented from being obstructed. This reduces the occurrence of uneven water flow and stagnation. As a result, the permeation capacity of the membrane leaf can be fully exerted.

[0030] In addition, forward osmosis occurs throughout the membrane reef as saltwater is supplied from the main pipeline and freshwater is supplied to the membrane reefs. This allows the membrane reef to exert its osmotic capacity and produce mixed water with increased energy.

[0031] In addition, the forward osmosis membrane module can be constructed with the main pipe and the membrane leaf as the main components. This simplifies the structure and reduces manufacturing and maintenance costs. In addition, the fewer components allow the membrane leaf that can be accommodated in the case to be larger, improving the forward osmosis performance. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a block diagram of a power generation system using a forward osmosis membrane module. [Diagram 2] This is a schematic diagram showing that in order to continue increasing the amount of water through a forward osmosis membrane, seawater (concentrated seawater) must be continuously supplied. [Diagram 3] 1 is a graph showing the correlation between forward osmosis membrane and power generation capacity to show the necessary conditions for power generation using a forward osmosis membrane. [Figure 4] FIG. 1 is a schematic diagram of a forward osmosis membrane using hollow fibers. [Diagram 5] FIG. 1 is an explanatory diagram for explaining problems with the conventional technology in which a partition is used to configure an inlet and an outlet for fresh water, as in Patent Documents 1 and 2. [Figure 6] FIG. 1 is a perspective view of a forward osmosis membrane module in a first embodiment of the present invention. [Figure 7] FIG. 1 is a development view of a forward osmosis membrane module in accordance with a first embodiment of the present invention. [Figure 8] FIG. 1 is a developed cross-sectional view of a forward osmosis membrane module in accordance with a first embodiment of the present invention. [Figure 9] FIG. 2 is a side view of a forward osmosis membrane module in a state in which it is assumed to be incorporated into a power generation device or the like. [Figure 10] FIG. 2 is a cross-sectional view showing a stored state of the membrane leaf in the first embodiment of the present invention. [Figure 11] FIG. 2 is a front view of a main pipe according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The forward osmosis membrane module according to the first aspect of the present invention comprises a case, A plurality of membrane leaves housed in the case to cause a forward osmosis phenomenon; A main pipe communicating with a saltwater flow path which is a gap between the plurality of membrane leaves, Salt water is supplied to the salt water flow path from the main pipe, Each of the plurality of membrane leaves has a first end and a second end, which are a pair of ends perpendicular to the main pipe, open, and fresh water is supplied into the membrane leaf from the first end, The fresh water supplied to the inside of the membrane reef moves in a first direction from the first end toward the second end, The saltwater supplied to the saltwater flow path moves in a second direction from a third end, which is an end of the membrane leaf on the main pipe side, toward a fourth end on the opposite side to the third end, Unpermeated water is discharged from the second end, The mixed water is discharged from the fourth end. A forward osmosis phenomenon occurs between the fresh water moving in the first direction inside the membrane reef and the salt water moving in the second direction in the salt water flow path, generating the mixed water and the non-permeated water.

[0034] This structure allows the forward osmosis phenomenon to be realized efficiently without providing a partition inside the membrane leaf. The forward osmosis phenomenon can be realized with high capacity, and mixed water with increased energy can be obtained.

[0035] In the forward osmosis membrane module according to the second aspect of the present invention, in addition to the features of the first aspect, the forward osmosis phenomenon in the membrane leaf is The fresh water inside the membrane reef permeates into the salt water in the salt water flow path; The amount of salt water increases, resulting in mixed water.

[0036] This configuration allows for the production of mixed water with increased energy content, which can be suitably used in power generation devices and the like.

[0037] In the forward osmosis membrane module according to the third aspect of the present invention, in addition to the first or second aspect of the present invention, fresh water that does not permeate during the forward osmosis phenomenon in the membrane leaf is discharged as the unpermeated water.

[0038] This configuration allows the forward osmosis phenomenon to be realized efficiently.

[0039] In a forward osmosis membrane module according to a fourth aspect of the present invention, in addition to any one of the first to third aspects, the first direction and the second direction are substantially perpendicular to each other.

[0040] This configuration allows efficient contact between salt water and fresh water through the membrane leaf, enhancing the capacity of forward osmosis.

[0041] A forward osmosis membrane module according to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects of the present invention, further comprises an internal spacer that forms an internal space of the membrane leaf, The internal spacer facilitates the supply of fresh water from the first end, the movement of fresh water within the membrane leaf, and the discharge of non-permeated water from the second end.

[0042] This configuration can enhance the forward osmosis effect.

[0043] A sixth aspect of the present invention provides a forward osmosis membrane module according to any one of the first to fifth aspects of the present invention, further comprising a channel spacer that forms an internal space of the salt water channel, The flow path spacer facilitates the supply of salt water from the third end, the movement of salt water through the salt water flow path, and the discharge of mixed water from the fourth end.

[0044] This configuration can improve the overall forward osmosis performance and operational performance.

[0045] A forward osmosis membrane module according to a seventh aspect of the present invention is characterized in that, in addition to any one of the first to sixth aspects, the main pipe includes a plurality of main pipe holes communicating with the salt water passage.

[0046] This configuration connects the main pipeline and the saltwater flow path, making the saltwater supply more efficient and dispersing the pressure in the saltwater supply.

[0047] In a forward osmosis membrane module according to an eighth aspect of the present invention, in addition to the features of the seventh aspect, each of the main pipe holes has a different opening area depending on the position of the main pipe.

[0048] This configuration allows for total dispersion of the salt water supply.

[0049] A forward osmosis membrane module according to a ninth aspect of the present invention is characterized in that, in addition to any one of the first to eighth aspects, the main pipe supplies salt water from at least one of its two ends.

[0050] This configuration can increase the salt water supply capacity, which in turn increases the forward osmosis capacity.

[0051] A forward osmosis membrane module according to a tenth aspect of the present invention is the forward osmosis membrane module according to any one of the first to ninth aspects of the present invention, further comprising: The plurality of membrane leaves are housed in a spiral shape with the main pipe near the center.

[0052] This configuration makes it possible to realize the forward osmosis phenomenon by making maximum use of the overall size.

[0053] In a forward osmosis membrane module according to an eleventh aspect of the present invention, in addition to any one of the first to tenth aspects, the mixed water is used to rotate an electricity-generating turbine.

[0054] With this configuration, a power generation device utilizing the forward osmosis phenomenon can be realized.

[0055] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0056] (Embodiment 1)

[0057] (Analysis by the inventor)

[0058] Figure 1 is a block diagram of a power generation system using a forward osmosis membrane module. As explained in the prior art, in areas where it is difficult to obtain natural freshwater from rivers, lakes, groundwater, etc., desalination facilities are used to desalinize seawater in order to obtain freshwater.

[0059] As shown in Figure 1, fresh water is obtained at seawater desalination plants (this fresh water is used for drinking water and other domestic and public water), but at the same time, concentrated seawater with an increased salt concentration is produced. Disposing of this concentrated seawater on soil can accelerate soil salinization and cause environmental damage. Disposing of concentrated seawater into the ocean also places a burden on the environment.

[0060] In order to make effective use of such concentrated seawater, a forward osmosis membrane as shown in Figure 1 is used to mix the concentrated seawater with fresh water (fresh water that has been used for domestic and public water and then purified at a sewage treatment facility) and allow the fresh water to permeate into the concentrated seawater. The forward osmosis membrane has an inlet for concentrated salt water and an inlet for fresh water. By permeating the fresh water into the concentrated seawater through the forward osmosis membrane, the amount of concentrated seawater increases and mixed water is obtained.

[0061] A forward osmosis membrane has an outlet for the mixed water and an outlet for the non-permeated water, which is the fresh water that did not completely permeate. Since the non-permeated water is fresh water, it is discharged. The mixed water has an increased volume and has energy, which is the integral of the increased volume and pressure. The mixed water with this energy rotates a power generating turbine (water wheel).

[0062] Electricity is generated by the rotation of this turbine. The mixed water is concentrated seawater, and the salinity has been reduced by the infiltration of fresh water. In theory, the salinity is at the same level as seawater. This means that the mixed water, once used for power generation, will not be an environmental burden even if it is dumped back into the sea.

[0063] In this way, it is possible to realize a total circulation system that uses seawater as the base, producing fresh water, treating sewage, and generating electricity using forward osmosis. It is necessary to have a technology that can generate the mixed water required for power generation using forward osmosis.

[0064] Figure 2 is a schematic diagram showing that in order for the forward osmosis membrane to continue increasing the amount of water, seawater (concentrated seawater) must be continuously supplied. If seawater is not continuously supplied, the forward osmosis phenomenon becomes insufficient, and it becomes impossible to obtain mixed water with an increased amount of water. This makes it impossible to sustain power generation. Therefore, a continuous supply of seawater is necessary. Of course, a continuous supply of freshwater is also necessary. As a result, a forward osmosis membrane used for power generation requires two inlets (salt water and fresh water) and two outlets (mixed water and unpermeated water).

[0065] Figure 3 is a graph showing the correlation between forward osmosis membrane and power generation capacity to show the necessary conditions for power generation using forward osmosis membrane. As shown in the graph in Figure 3, in order to obtain high net power generation, it is necessary that the value obtained by subtracting the power consumption of the entire system from the integral of the water volume and pressure increased by the forward osmosis phenomenon is large.

[0066] There is a limit to how much power consumption can be reduced, and the pressure setting is also determined by the properties of the forward osmosis membrane. In other words, it is necessary to increase the amount of water increased by the forward osmosis phenomenon in order to obtain a high net power generation. In other words, the forward osmosis membrane needs to have a high permeation capacity. In addition, as a prerequisite, two inlets (salt water and fresh water) and two outlets (mixed water and unpermeated water) are necessary.

[0067] Figure 4 is a schematic diagram of a forward osmosis membrane using hollow fibers. A large number of hollow fibers, which are thin tubes, are packed together at a high density.

[0068] However, the permeability per unit area of ​​the hollow fiber type is lower than that of the spiral type because the permeability is limited by the thin tubes. This is because the contact area between the fresh water supplied to the hollow fiber and the salt water supplied to its periphery is small, which limits the permeability per unit area.

[0069] In addition, there is a problem with hollow fiber type forward osmosis membrane modules, where technological development has already progressed to pack the hollow fibers to their maximum density as shown in Figure 4. When the inventors conducted experiments using a hollow fiber type forward osmosis membrane module, they were unable to generate sufficient power generation to exceed the power consumption shown in Figure 3.

[0070] Thus, it is insufficient to use a hollow fiber type forward osmosis membrane module in a power generation system.

[0071] Therefore, the inventors have considered utilizing a spiral-type forward osmosis membrane module based on a membrane leaf having a planar space using a flat membrane with excellent water permeability. However, as explained in the prior art, a typical spiral-type forward osmosis membrane module cannot have two inlets and two outlets. Therefore, a partition is provided in the membrane leaf as in Patent Documents 1 and 2 listed in the prior art. A technology has been proposed in which one end of the center pipe is an inlet for fresh water, and the other end is an outlet for discharging unpermeated water that has returned to the center pipe through a partition in the membrane leaf.

[0072] Fig. 5 is an explanatory diagram for explaining problems with the conventional technology in which a partition is used to configure a freshwater inlet and outlet as in Patent Documents 1 and 2. As shown in Fig. 5, freshwater is supplied from one end of a center pipe connected to a membrane reef. The freshwater moves from the center pipe to the membrane reef. Inside the membrane reef, the freshwater moves along the arrows to avoid the partition based on the water pressure (freshwater movement path in Fig. 5).

[0073] The center pipe is divided in the middle, and the fresh water that moves through the membrane leaf becomes unpermeated water after forward osmosis and is discharged from the opposite end of the center pipe. Salt water is supplied to the outside of the membrane leaf (the gap between the membrane leaves) and moves. As a result, the salt water and fresh water come into contact through the membrane of the membrane leaf, causing forward osmosis. The fresh water permeates through the membrane leaf into the salt water side, increasing the amount of water on the salt water side.

[0074] However, as shown in Figure 5, the fresh water returns to the center pipe on the inlet side by avoiding the partition, resulting in areas where the fresh water flow is poor (such as the triangular area in Figure 5). Poor flow causes stagnation, which reduces the infiltration capacity in this area. As a result, the overall infiltration capacity is reduced.

[0075] Increasing the water pressure of the freshwater supply to reduce stagnation lowers the pressure gradient between the freshwater side and the saltwater side, weakening the infiltration of saltwater through the membrane reef and again reducing the infiltration capacity.

[0076] As described above, the conventional forward osmosis membrane having two inlets and two outlets had a problem in that it was not possible to increase the osmosis membrane capacity.

[0077] The inventors arrived at the present invention based on such analysis.

[0078] (Overview) Fig. 6 is a perspective view of the forward osmosis membrane module in the first embodiment of the present invention. Fig. 6 shows the outer shape of the forward osmosis membrane module 1 in use. Fig. 7 is a development view of the forward osmosis membrane module in the first embodiment of the present invention. Fig. 7 shows a state in which one of the multiple membrane leaves constituting the forward osmosis membrane module 1 is developed in correspondence with the main pipeline.

[0079] The forward osmosis membrane module 1 includes a case 2, a plurality of membrane leaves 5, and a main pipe 3. In Fig. 6, the case 2 is shown in a schematic manner in order to easily understand the internal configuration of the forward osmosis membrane module 1. The case 2 may have a more mechanical structure in order to use or incorporate the forward osmosis membrane module 1.

[0080] Moreover, the case 2 is a member that houses the main pipe 3 and the membrane leaf 5 wound in a spiral shape. The case 2 may be made of a material having structural strength such as resin or metal, or may be made of a net or thin film that can maintain the shape of the internal element (the shape of the membrane leaf 5 wound in a spiral shape around the main pipe 3). Furthermore, since the mixed water is discharged from the gaps between the membrane leaves 5, the case 2 has an opening for discharging this mixed water. Whatever the material of the case 2, it has an opening for discharging such mixed water.

[0081] A plurality of membrane leaves 5 are housed inside the case 2. The membrane leaves 5 cause a forward osmosis phenomenon. That is, when fresh water is supplied inside the membrane leaf 5 and salt water is supplied outside the membrane leaf 5, a forward osmosis phenomenon occurs in which water permeates from the fresh water to the salt water. The membrane leaf 5 causes such a forward osmosis phenomenon.

[0082] The main pipe 3 communicates with each gap between the multiple membrane leaves 5. The gaps between the multiple membrane leaves 5 are saltwater passages 6 through which saltwater moves. That is, the main pipe 3 communicates with the saltwater passage 6. The main pipe 3 supplies saltwater to the saltwater passage 6 through this communication.

[0083] Salt water is water that contains various salt contents, such as seawater, artificial salt water, and concentrated seawater.

[0084] The main pipe 3 has a main pipe inlet 31. Saltwater is supplied to the main pipe 3 from this main pipe inlet 31. The saltwater supplied to the main pipe 3 moves to the communicating saltwater flow path 6. At this time, the main pipe 3 has a main pipe hole 35. The main pipes are communicated through the main pipe hole 35, and saltwater can move from the main pipe 3 to the saltwater flow path 6 through this main pipe hole 35. The arrow related to the saltwater in Figure 7 indicates the movement direction of the saltwater.

[0085] Salt water moves through the salt water passage 6 along the second direction shown in Fig. 7. The salt water moves based on the water pressure of the salt water supply. That is, the salt water moves from the third end 61 toward the fourth end 62. This is the second direction.

[0086] A plurality of membrane leaves 5 are each connected to the main pipe 3. As shown in Fig. 7, one end of the membrane leaf 5 is connected to the main pipe 3. However, the membrane leaf 5 and the main pipe 3 are not in communication with each other. As a result, salt water supplied to the main pipe 3 does not move into the inside of the membrane leaf 5, but moves to the salt water flow path 6 which is the gap between the membrane leaves 5.

[0087] In this way, salt water is supplied to the salt water flow paths 6, which are the gaps between the membrane leaves 5. The salt water moves through the salt water flow paths 6. This movement allows the fresh water inside the membrane leaf 5 and the salt water outside the membrane leaf 5 to come into indirect contact, via the interface of the membrane leaf 5, allowing forward osmosis.

[0088] Since the membrane leaves 5 can be connected to the main pipe 3 without communicating with each other, the multiple membrane leaves 5 and the main pipe 3 can be configured to be securely accommodated in the case 2.

[0089] As shown in Fig. 7, the membrane leaf 5 has a pair of open ends, a first end 51 and a second end 52, which are perpendicular to the main pipe 3. In Fig. 7, there is the first end 51 that faces the direction in which fresh water is supplied, and the second end 52 on the diagonal side. The first end 51 and the second end 52 are open and communicate with the outside. Conversely, one of the ends other than the first end 51 and the second end 52 is connected to the main pipe 3 as described above. The other end is closed.

[0090] Fresh water is supplied to the inside of the membrane leaf 5 from the first end 51 of the membrane leaf 5. The fresh water supplied to the inside of the membrane leaf 5 moves inside the membrane leaf 5 based on the water pressure of the fresh water supply. It moves in a first direction in FIG. 7 .

[0091] In this way, salt water moves in the second direction from the third end 61 to the fourth end 62 through the salt water flow path 6 which is the gap between the membrane leaves 5 and outside the membrane leaves 5. In parallel, fresh water moves in the first direction from the first end 51 to the second end 52 inside the membrane leaves 5. In this movement of fresh water and salt water, forward osmosis occurs due to indirect contact via the membrane leaves 5.

[0092] Due to this forward osmosis phenomenon, the moisture in the freshwater inside the membrane leaf 5 permeates into the saltwater in the saltwater flow path 6. As a result, the moisture content and energy content of the saltwater increases. This is the mixed water. Meanwhile, the freshwater that does not permeate is the unpermeated water. The mixed water is discharged from the fourth end 62, which is the outlet of the saltwater flow path 6. The unpermeated water is discharged from the second end 52, which is the outlet of the membrane leaf 5.

[0093] The mixed water has an increased amount of energy and water. This mixed water is used, for example, to rotate a power generating turbine. This allows the mixed water to be used in power generating equipment, etc. That is, the forward osmosis membrane module 1 can be used in power generating equipment, etc. Since it has a higher amount of energy than the supplied salt water and is obtained by the forward osmosis phenomenon, it can be used in the power generating equipment with more energy than the energy used.

[0094] As a result, mixed water suitable for use in power generation devices and the like can be obtained. This mixed water is produced by increasing the amount of salt water, and therefore has an increased amount of energy. The efficiency of the forward osmosis phenomenon that realizes this increase is higher than that of conventional technology, and this makes the mixed water more advantageous in its uses. For example, if the salt water supplied is concentrated seawater, the mixed water will have about 30 times the energy, and if it is seawater, the mixed water will have about 15 times the energy.

[0095] In addition, even if the saltwater is concentrated saltwater or seawater, fresh water penetrates into the water during the process of mixing it. This reduces the salinity of the mixed water. Therefore, even if the mixed water is dumped into the sea after being used in power generation equipment, it does not pose a burden on the environment.

[0096] In the forward osmosis membrane module 1, the first end 51 and the second end 52 of the membrane leaf 5 are open. This structure increases the supply capacity of fresh water to the membrane leaf 5. This also increases the capacity of the forward osmosis phenomenon.

[0097] Due to the forward osmosis phenomenon between the fresh water moving in the first direction and the salt water moving in the second direction, mixed water is generated in the salt water flow path 6, and non-permeated water is generated inside the membrane leaf 5. Each of these is discharged and can be used for required purposes.

[0098] Moreover, since the non-permeated water is discharged from the second end 52, the non-permeated water is also efficiently discharged. In addition, no mechanism for discharging the non-permeated water is required other than the membrane leaf 5, and the storage efficiency inside the case 2 can be improved.

[0099] The multiple membrane leaves 5 are stored in a spiral shape inside the case 2. In this stored state, the membrane leaves 5 do not require a mechanism for discharging unpermeated water, so that the storage efficiency inside the case 2 is increased.

[0100] It is also preferable that the first direction and the second direction are approximately perpendicular to each other. Of course, they may be other than approximately perpendicular depending on the shape of the membrane leaf 5 and the connection state with the main pipe 3. When the movement directions are approximately perpendicular to each other, the forward osmosis phenomenon occurs efficiently.

[0101] The high-energy mixed water obtained in this manner is used for power generation, so that the efficiency is very high even when a forward osmosis membrane module is used in a power generation facility, etc. In this way, the forward osmosis membrane module 1 of the present invention solves the problems of the conventional technology and enables the generation of mixed water with high efficiency.

[0102] Here, the salt water may be naturally occurring salty water such as seawater, or may be artificially produced salty water, or may be concentrated seawater produced by a desalination device.

[0103] Furthermore, the fresh water and salt water may be any water that generates an osmotic pressure difference that causes the forward osmosis phenomenon. Therefore, the fresh water includes not only completely fresh water, but also water with a lower salinity than the salt water supplied to the salt water flow passage. For example, concentrated seawater may be supplied to the salt water flow passage, and normal seawater may be supplied to the membrane reef 5. In this case, the salinities are different, causing an osmotic pressure difference. This causes the forward osmosis phenomenon.

[0104] 8 is a side view of a forward osmosis membrane module in an embodiment of the present invention. It shows a side cross section with elements housed in a case 2. A plurality of membrane leaves 5 and a main pipe 3 are housed in the case 2. The case 2 is provided with a case inlet and a case outlet, which may be connected to the supply of salt water or fresh water, and to the discharge of mixed water or non-permeated water.

[0105] Being housed in a case having such an external shape makes it easier to apply the device to various devices and facilities such as power generation devices.

[0106] Next, we will explain the details and variations of each part.

[0107] (Membrane Reef Housing) Fig. 9 is a cross-sectional view of a forward osmosis membrane module in an embodiment of the present invention. It shows a cross section in the horizontal direction when housed inside the case 2. As shown in Fig. 9, the multiple membrane leaves 5 are housed in a spiral shape based on the main pipe 3 near the center inside the case 2. Although shown as a development view in Fig. 7, they are housed in a spiral shape.

[0108] Being stored in a spiral shape improves storage efficiency. Also, being stored in a spiral shape makes use of the surface area of ​​the membrane leaf 5 inside the case 2. This allows the movement of fresh water and salt water (salt water moves through the salt water flow paths 6 in the gaps between the membrane leaves 5) to occur throughout the entire membrane leaf 5. In other words, forward osmosis occurs by utilizing the entire membrane leaf 5.

[0109] This forward osmosis phenomenon utilizing the entire water can increase the amount of energy in the mixed water. In addition, the forward osmosis membrane module 1 can be easily miniaturized and incorporated into a power generation device.

[0110] Further, each of the membrane leaves 5 is connected to the main pipe 3 at the third end 61. As shown in Fig. 9, the main pipe 3 is provided near the center of the case 2, and the membrane leaves 5 are spiraled around the main pipe 3, which makes it easy to accommodate them inside the case 2.

[0111] Furthermore, multiple membrane leaves 5 are housed inside the case 2. For this reason, a very large amount of mixed water can be obtained with one forward osmosis membrane module 1. In addition to the increased energy of the mixed water, the ability to obtain a large amount of mixed water makes it suitable for use in power generation devices and the like.

[0112] (Salt water movement and forward osmosis) Fig. 10 is a cross-sectional view of a forward osmosis membrane module in an embodiment of the present invention, in which the module is unfolded. The main pipe 3 communicates with the saltwater passage 6 through the main pipe hole 35. This communication allows saltwater supplied to the main pipe 3 to move to the saltwater passage 6. The saltwater passage 6 is a gap between the membrane leaves 5, and in the spirally folded state as shown in Fig. 9, saltwater moves in the second direction through the saltwater passage 6, which is the gap between the membrane leaves 5.

[0113] Furthermore, the fresh water supplied inside the membrane leaf 5 moves in the first direction inside the membrane leaf 5. As a result, the fresh water inside the membrane leaf 5 and the salt water outside move while indirectly contacting each other via the outer surface of the membrane leaf 5. During the movement process, the forward osmosis phenomenon occurs. Due to this phenomenon, the water in the fresh water moves into the salt water, generating mixed water. The mixed water has an increased amount of energy compared to the initial salt water.

[0114] (Internal spacer and flow path spacer) As shown in FIG. 7 and FIG. 10, it is also preferable to provide an internal spacer 55 which defines an internal space inside the membrane leaf 5, and a channel spacer 60 which defines an internal space of the salt water channel 6.

[0115] By providing the internal spacer 55 inside the membrane leaf 5, an internal space of the membrane leaf 5 is secured even when a plurality of membrane leaves 5 are stored by being folded in a spiral shape. By securing this internal space, fresh water can move inside the membrane leaf 5.

[0116] The internal spacer 55 can promote the supply of fresh water from the first end 51, the movement of the fresh water inside the membrane leaf 5, and the discharge of non-permeated water from the second end 52. In other words, these can be ensured.

[0117] Similarly, by providing the channel spacer 60 in the saltwater channel 6, even when a plurality of membrane leaves 5 are stored by being folded in a spiral shape, a space can be secured between the membrane leaves 5. This ensures that the saltwater channel 6 is secured. The saltwater moves sufficiently in the saltwater channel 6.

[0118] The flow path spacer 60 promotes the supply of salt water from the third end 61, the movement of salt water in the salt water flow path 6, and the discharge of the mixed water from the fourth end 62. In other words, these can be reliably performed.

[0119] In this way, by providing the internal spacer 55 and the flow path spacer 60, even if multiple membrane leaves 5 are folded in a spiral shape and stored, the operation required to cause the forward osmosis phenomenon and the discharge operation can be performed reliably. As a result, the operation and function of the forward osmosis membrane module 1 can be improved in reliability and level.

[0120] (Main pipe and main pipe hole) The main duct 3 is housed near the center inside the case 2. This embodiment is shown in Figure 9. A plurality of membrane leaves 5 are connected to the main duct 3.

[0121] Here, the main pipe 3 is provided with a main pipe hole 35. The main pipe hole 35 communicates with the salt water passage 6 to realize the movement of salt water from the main pipe 3 to the salt water passage 6.

[0122] The main pipe hole 35 communicates with the salt water passage 6, and is provided in the gap between the membrane leaves 5. As a result, salt water does not enter the membrane leaves 5, and only enters the gap, the salt water passage 6. In this way, salt water is supplied to the salt water passage 6.

[0123] Fig. 11 is a front view of the main pipe in the embodiment of the present invention. As shown in Fig. 11, it is also preferable that the opening area of ​​each of the main pipe holes 35 differs depending on the position of the main pipe 3. In Fig. 11, the opening area of ​​the main pipe holes 35 increases as the distance from the main pipe inlet 31 of the main pipe 3 increases.

[0124] Due to such a change, when saltwater supplied from the main pipe inlet 31 moves inside the main pipe 3 and then moves perpendicularly to the saltwater flow path 6, the total amount of movement can be averaged. This is because the further away the water pressure drops, the larger the opening area becomes, making it easier to supply saltwater at the same level as the closer area.

[0125] That is, the opening area is small at the main pipe inlet 31 side where the water pressure remains strong, and is large at the tip side where the water pressure drops. This makes it easier to equalize the supply amount and supply level of fresh water depending on the position in response to changes in water pressure. This is because the large opening area at the tip where the water pressure is weak can reduce the difference in the amount of fresh water supplied to the membrane leaf 5 from the front side.

[0126] In addition to the opening area, the adjacent distance between the main pipe holes 35 may also be changed. The more distant the main pipe hole 35 is from the main pipe inlet 31, the smaller the adjacent distance between the main pipe holes 35 becomes. This also leads to uniformity in the salt water supply.

[0127] If the membrane leaf 5 is made uniform, the forward osmosis phenomenon can be efficiently performed throughout the membrane leaf 5. This ensures that mixed water with increased energy content can be obtained. In addition, the load imbalance in the salt water passage 6 can be reduced, improving durability.

[0128] In Fig. 7 etc., salt water is supplied from the main pipe inlet 31 on one side of the main pipe 3, but salt water may be supplied from both ends of the main pipe 3. Supplying salt water from both ends makes it more efficient to supply salt water to the salt water flow path 6. In addition, the durability of the membrane leaf 5 that constitutes the salt water flow path 6 can be improved.

[0129] It is also preferable to control the balance between the amount of fresh water supplied to the membrane leaf 5 and the amount of salt water supplied to the salt water passage 6. It is also preferable to control not only the amount but also the supply speed and the movement speed at the supply stage.

[0130] (Mixed water and non-permeated water) The mixed water generated by moving through the saltwater passage 6 is discharged from the fourth end 62. The mixed water has an increased amount of energy. This is used to rotate a power generating turbine. Of course, the mixed water may be used for purposes other than power generating turbines.

[0131] The mixed water has a lower salinity than the saltwater at the supply stage because it is subject to forward osmosis from the fresh water. Therefore, even if the mixed water is discharged after being used in power generation equipment, etc., it does not cause an environmental burden. For example, even if seawater or concentrated seawater (concentrated saltwater) is used as the salt water, the mixed water has a salinity equal to or lower than seawater. Therefore, even if the mixed water is discharged into the sea, it does not cause an environmental burden.

[0132] In this way, the forward osmosis membrane module 1 of the present invention can maximize the capacity of the membrane leaf 5 to obtain mixed water that can be optimally used for power generation equipment, etc. In addition, the environmental load can be reduced.

[0133] The non-permeated water that has moved inside the membrane leaf 5 is discharged from the second end 52 of the membrane leaf 5. This allows the non-permeated water that is no longer needed to be discharged. Since the non-permeated water is fresh water, it does not cause an environmental problem even if it is discharged as it is.

[0134] By using the forward osmosis membrane module 1 of the present invention in a power generation device, power generation can be realized in various places where salt water is available. This means that it can be used in places where thermal, wind, or hydroelectric power generation cannot be installed, leading to the supply of power even in areas where it is difficult to supply power. Power generation can be achieved near the sea or near salt lakes. This makes it possible to supply power in developing countries and inland areas where it is difficult to install thermal or hydroelectric power plants. As a result, it also leads to global and regional development.

[0135] The forward osmosis membrane module described in the embodiment is an example for explaining the gist of the present invention, and includes modifications and alterations without departing from the gist of the present invention. [Explanation of symbols]

[0136] 1. Forward osmosis membrane module 2 Cases 3 Main pipeline 31 Main pipeline entrance 35 Main pipe hole 5. Membrane Reef 51 First end 52 Second end 55 Internal spacer 6 Saltwater Channel 61 Third end 62 4th end 60 Flow path spacer

Claims

1. Case and A plurality of membrane leaves housed in the case to cause a forward osmosis phenomenon; A main pipe communicating with a saltwater flow path which is a gap between the plurality of membrane leaves, Salt water is supplied to the salt water flow path from the main pipe, Each of the plurality of membrane leaves has a first end and a second end, which are a pair of ends perpendicular to the main pipe, open, and fresh water is supplied into the membrane leaf from the first end, The fresh water supplied to the inside of the membrane leaf moves in a first direction from the first end toward the second end, The salt water supplied to the salt water flow path moves in a second direction from a third end portion, which is an end portion of the membrane leaf on the main pipe side, toward a fourth end portion on the opposite side to the third end portion, Unpermeated water is discharged from the second end, The mixed water is discharged from the fourth end. A forward osmosis membrane module in which a forward osmosis phenomenon occurs between the fresh water moving in the first direction inside the membrane leaf and the salt water moving in the second direction in the salt water flow path, generating the mixed water and the unpermeated water.

2. Due to the forward osmosis phenomenon in the membrane leaf, The fresh water inside the membrane reef permeates into the salt water in the salt water flow path; The forward osmosis membrane module of claim 1 , wherein the amount of the salt water increases to produce mixed water.

3. 3. The forward osmosis membrane module according to claim 1, wherein fresh water that does not permeate through the membrane leaf in the forward osmosis phenomenon is discharged as the non-permeated water.

4. The forward osmosis membrane module according to claim 1 , wherein the first direction and the second direction are substantially perpendicular to each other.

5. an internal spacer that defines an internal space of the membrane leaf; 5. The forward osmosis membrane module according to claim 1, wherein the internal spacer facilitates the supply of fresh water from the first end, the movement of fresh water inside the membrane leaf, and the discharge of non-permeated water from the second end.

6. A flow path spacer that forms an internal space of the salt water flow path is further provided, The forward osmosis membrane module according to claim 1 , wherein the flow path spacer facilitates the supply of salt water from the third end, the movement of salt water in the salt water flow path, and the discharge of mixed water from the fourth end.

7. The forward osmosis membrane module according to claim 1 , wherein the main conduit has a plurality of main conduit holes communicating with the salt water flow path.

8. The forward osmosis membrane module according to claim 7 , wherein each of the plurality of main pipe holes has a different opening area at a position of the main pipe.

9. The forward osmosis membrane module according to claim 1 , wherein salt water is supplied from at least one of both ends of the main pipe.

10. the case houses the plurality of membrane leaves; The forward osmosis membrane module according to claim 1 , wherein the plurality of membrane leaves are housed in a spiral shape with the main pipe near the center.

11. 11. The forward osmosis membrane module of claim 1, wherein the mixed water is used to spin an electricity-generating turbine.

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