Method for dewatering a spiral membrane element

Abstract

Provided is a method for dehydrating a spiral membrane element, which can effectively remove moisture contained in a used spiral membrane element by a simple method. The method for dehydrating a spiral membrane element according to the present invention is a method for dehydrating a spiral membrane element E that contains moisture, the spiral membrane element E having a winding body and a perforated center tube, the winding body including a plurality of membrane sheets wound on the center tube and having a permeation-side flow path inside. Furthermore, the method for dehydrating a spiral membrane element according to the present invention includes a step of forming an opening (for example, an end face opening formed by a cut surface 16) that communicates the permeation-side flow path with the outside on the plurality of membrane sheets, and a step of applying a centrifugal force to the spiral membrane element on which the opening is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for reducing moisture contained in a used spiral membrane element (hereinafter sometimes referred to simply as "membrane element"). BACKGROUND

[0002] Conventionally, a spiral membrane element is manufactured by winding a separation membrane which is a flat membrane, a permeation-side flow path material, and a supply-side flow path material around a center pipe with a hole, and constructing FRP (fiber reinforced plastic) as an outer layer covering material on the outer periphery of the obtained winding body. At this time, ATD (Anti-telescoping device) installed at both ends of the membrane element is integrated at the time of construction of the FRP.

[0003] The outer layer covering FRP is usually made of GFRP (glass FRP), and has sufficient strength because it is reinforced with glass fibers. In addition, the ATD is firmly integrated by the GFRP.

[0004] The spiral membrane element deteriorates over time due to its use, contamination of the membrane surface, and the like, and as a result, the performance decreases over time. With respect to contamination of the membrane surface, although it can be recovered to some extent by physical washing of the contaminant by increasing the flow rate on the supply liquid side, which is called flushing, or chemical washing by a chemical agent, even so, there comes a time when the limit is reached, and the membrane element itself needs to be replaced.

[0005] The disposal method of the used membrane element after replacement is a big problem, and landfill disposal is limited in the volume of disposal sites where disposal can be performed, and in addition, the membrane element, which is mostly plastic material, remains semi-permanently in the ground because it cannot be decomposed in the ground, so it is difficult to say that it is a sustainable disposal method. On the other hand, in the case of incineration disposal, the membrane element contains a large amount of moisture even after use, and incineration requires a large amount of energy. In addition, even if incineration is not performed, from the viewpoint of transportation and disposal of the membrane element, it is desirable to remove moisture in advance. SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, it is difficult to effectively remove moisture from the membrane element, and for example, even if moisture is sucked from the center pipe, there is a lot of residual moisture, and it cannot be said that it is a sufficient dehydration method. In addition, in the membrane element, the FRP outer layer covering material and the ATD are firmly fixed, so it is also not easy to remove moisture after decomposition.

[0008] Therefore, an object of the present application is to provide a method for dehydrating a spiral membrane element, which can effectively remove moisture contained in a used spiral membrane element by a simple method.

[0009] Means for solving the problem

[0010] The above object can be achieved by the present application as follows.

[0011] That is, the method for dehydrating a spiral membrane element of the present application is a method for dehydrating a spiral membrane element for reducing moisture contained in a used spiral membrane element, wherein the spiral membrane element has a winding body and a perforated center tube, the winding body includes a plurality of membrane sheets wound on the center tube and having a permeation-side flow path inside, the method for dehydrating a spiral membrane element includes a step of forming an opening on the plurality of membrane sheets, the opening allowing the permeation-side flow path to communicate with the outside, and a step of applying a centrifugal force to the spiral membrane element having the opening formed.

[0012] According to the method for dehydrating a spiral membrane element of the present application, an opening is formed on the plurality of membrane sheets, the opening allowing the permeation-side flow path to communicate with the outside, and then a centrifugal force is applied to the spiral membrane element, so that moisture in the permeation-side flow path enclosed in the membrane sheets is easily discharged to the outside of the opening via the opening. That is, in the membrane element, since the supply-side flow paths between the membrane sheets communicate with the outside, dehydration can be effectively performed using a centrifugal force, but moisture in the permeation-side flow path enclosed in the membrane sheets can only be discharged via the center tube (time is required for permeation of the separation membrane). In contrast, by providing the opening as described above, moisture in the membrane sheets is caused to flow to the opening by the centrifugal force, and is directly discharged from the membrane element or discharged from the membrane element via the supply-side flow path. Alternatively, depending on the position of the opening, in addition to being able to discharge moisture from the opening, by flowing air from the opening, discharge of moisture via other openings or the center tube can be promoted. As a result, by a simple method, moisture contained in a used spiral membrane element can be effectively removed.

[0013] It is preferable that at least a part of the opening is disposed at a position where the centrifugal force is larger than the position of the center of gravity of the spiral membrane element in a dried state when the centrifugal force is applied. By this, moisture present at the position of the center of gravity and the position where the centrifugal force is smaller than the position of the center of gravity can be effectively caused to flow to the position where the centrifugal force is larger, and the moisture can be effectively discharged from the opening. Therefore, residual moisture can be removed at a higher speed.

[0014] In the above, it is preferable that the centrifugal acceleration at the position where the centrifugal force is the largest in the spiral membrane element is 50 G (490 m / s 2) above. When the flow of moisture is generated at the portion where the centrifugal force is the largest, a suction force is generated for the moisture of the portion where the centrifugal force is small, and thus by applying such a centrifugal force to the portion where the centrifugal force is the largest, the moisture can be removed from the spiral membrane element more efficiently.

[0015] Further, it is preferable that the spiral membrane element be arranged so that the axial direction thereof is substantially parallel to the direction of the centrifugal force when the centrifugal force is applied, and the opening includes an end face opening formed by a cut surface provided at an end portion on the side where the centrifugal force is large. Since the permeation side flow path and the supply side flow path of the spiral membrane element are configured so that the moisture can flow along the axial direction of the membrane element, by arranging the axial direction substantially parallel to the direction of the centrifugal force, the flow can be generated efficiently. Further, the moisture can be efficiently discharged from the opening formed by the cut surface provided at the end portion on the side where the centrifugal force is large. Further, the cutting of the end portion of the membrane element can be performed by a relatively easy operation.

[0016] Alternatively, it is preferable that the spiral membrane element be arranged so that the axial direction thereof is inclined with respect to the direction of the centrifugal force when the centrifugal force is applied, and the opening includes an end face opening formed by a cut surface provided at an end portion on the side where the centrifugal force is large. In this case, since the axial direction of the membrane element is arranged inclined with respect to the direction of the centrifugal force, the flow efficiency is reduced compared to the case where the axial direction is arranged substantially parallel to the direction of the centrifugal force, but the radius of rotation can be further reduced, and thus the number of processes per unit device installation area can be increased.

[0017] Alternatively, it is preferable that the spiral membrane element be arranged so that the axial direction thereof is substantially perpendicular to the direction of the centrifugal force when the centrifugal force is applied, and the opening includes a split face opening formed by a cut slit provided from the outer peripheral portion on the side where the centrifugal force is large toward the center pipe. In this case, since the axial direction of the membrane element is arranged substantially perpendicular to the direction of the centrifugal force, the number of processes per unit device installation area can be further increased. Further, since the split face opening is provided from the outer peripheral portion on the side where the centrifugal force is large toward the center pipe, the moisture present in the permeation side flow path around the center pipe is directly discharged to the outside of the membrane element from the split face opening. Thus, the moisture can be efficiently removed.

[0018] Effects of the Invention

[0019] The dehydration method of a spiral membrane element according to the present application can provide a dehydration method of a spiral membrane element which can efficiently remove the moisture contained in a used spiral membrane element by a simple method. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1A A top view schematically illustrating an example of a dehydration apparatus used in the dehydration method of the spiral membrane element of the present invention.

[0021] Figure 1B The image shows a front view of an example of a dewatering apparatus used in the dewatering method of the spiral membrane element of the present invention, and a portion of the dewatering apparatus is shown in cross section.

[0022] Figure 2A This is a perspective view showing an example of a spiral membrane element used in this invention, with a portion removed.

[0023] Figure 2B This is an unfolded view showing an example of a spiral membrane element used in this invention, and is a view showing one of the membrane sheets unfolded.

[0024] Figure 3A This is a top view showing an example of the main parts of the dehydration apparatus used in the dehydration method of the spiral membrane element of the present invention.

[0025] Figure 3B This is a side view showing an example of the main part of the dehydration apparatus used in the dehydration method of the spiral membrane element of the present invention, viewed from the rotation axis side.

[0026] Figure 4 A front view schematically illustrating another example of a dewatering apparatus used in the dewatering method of the spiral membrane element of the present invention, and a portion of the dewatering apparatus shown in cross section.

[0027] Figure 5A A front view schematically illustrating another example of a dewatering apparatus used in the dewatering method of the spiral membrane element of the present invention, and a portion of the dewatering apparatus shown in cross section.

[0028] Figure 5B To indicate in Figure 5A A perspective view of an example of a spiral membrane element used in the dehydration apparatus shown. Detailed Implementation

[0029] (Dehydration method for spiral membrane elements)

[0030] The dehydration method of the spiral membrane element of the present application is a dehydration method of reducing the moisture contained in a used spiral membrane element, wherein the spiral membrane element as the object has a winding body and a perforated center tube, the winding body including a plurality of membrane sheets wound on the center tube and having a permeation-side flow path inside. Also, the dehydration method of the present application is characterized in that the dehydration method includes the following steps: a step of forming an opening that communicates the permeation-side flow path with the outside on the plurality of membrane sheets; and a step of applying a centrifugal force to the spiral membrane element on which the opening is formed.

[0031] The opening that communicates the permeation-side flow path with the outside can be formed, for example, by a cutting device, a perforating device, a cutting device. For example, the opening can be formed by cutting of one or both end portions of the membrane element, cutting parallel or inclined to the axial direction, cutting into the center tube from the outer periphery, a hole provided from the outer periphery to the center tube, cutting of the outer peripheral portion or the end portion, or the like.

[0032] The opening is formed on the plurality of membrane sheets, preferably on 50% or more of the membrane sheets, more preferably on 80% or more of the membrane sheets, and most preferably on all of the membrane sheets. As for the cutting, the cutting-in, the cutting for forming the opening, it is preferable to be performed at one site in order to simplify the process, but it can be performed at a plurality of sites.

[0033] By forming the opening that communicates the permeation-side flow path with the outside, at least a part of the moisture present in the permeation-side flow path can be discharged regardless of the position of the opening, but as the position of the opening, it is preferable to arrange at least a part of the opening at a position where the centrifugal force is greater compared to the position of the center of gravity in the dry state of the spiral membrane element. From the viewpoint of efficiently discharging the moisture, it is more preferable to arrange 50% or more of the total area of the opening at a position where the centrifugal force is greater compared to the position of the center of gravity, it is further preferable to arrange 80% or more of the total area of the opening at a position where the centrifugal force is greater compared to the position of the center of gravity, and it is most preferable to arrange 100% of the total area of the opening at a position where the centrifugal force is greater compared to the position of the center of gravity.

[0034] The centrifugal force can be applied, for example, by a dehydration device having a rotation mechanism. The centrifugal force can be adjusted, for example, by the radius of rotation and the rotational speed. The centrifugal force refers to the magnitude in the state where the rotational speed is gradually increased to a constant rotational speed, but the centrifugal force does not have to be constant, and the centrifugal force can be gradually or continuously changed.

[0035] The centrifugal acceleration at the portion where the centrifugal force is the greatest in the spiral membrane element is preferably 50G (490 m / s 2) Above, 100 G or more is more preferable. In addition, from the viewpoint of durability of the dewatering device, structural load, manufacturing cost, and the like, the centrifugal acceleration at the portion where the centrifugal force is the largest is preferably 1000 G or less, and more preferably 500 G or less. In the present application, when the centrifugal force is applied, it is preferable to at least include such a centrifugal force.

[0036] As the direction in which the centrifugal force is applied, it can be a direction that is substantially parallel, inclined, or substantially perpendicular to the axial direction of the membrane element. Here, "substantially parallel" means that the angle between the axial direction and the direction of the centrifugal force is 0° or more and less than 10°, and "substantially perpendicular" means that the angle between the axial direction and the direction of the centrifugal force is more than 80° and 90° or less. "Inclined direction (inclination direction)" means that the angle between the axial direction and the direction of the centrifugal force is 10° or more and 80° or less.

[0037] That is, the dewatering method of the present application includes: a first embodiment in which the axial direction of the membrane element is arranged substantially parallel to the direction of the centrifugal force when the centrifugal force is applied; a second embodiment in which the axial direction of the membrane element is arranged inclined to the direction of the centrifugal force; and a third embodiment in which the axial direction of the membrane element is arranged substantially perpendicular to the direction of the centrifugal force.

[0038] Hereinafter, the constitution that is advantageous for recycling and the spiral type membrane element that is the object will be described, and each embodiment will be described in detail.

[0039] (Constitution that is advantageous for recycling)

[0040] The membrane element after dewatering has the moisture sufficiently removed, and is advantageous for various recycling or landfill treatment. In particular, in the case of heat recycling that is effective use of fuel for processes such as papermaking factories, metal smelting, cement manufacturing, and the like, it is possible to improve the quality and value as fuel. Specifically, when the membrane element is used as RPF (Refuse paper and plastic fuel) fuel, it is possible to relatively increase the heat generated at the time of incineration.

[0041] In the case of heat recycling, in the outer layer covering material FRP of the spiral type membrane element, it is preferable to use a flammable fiber instead of glass fiber. As the flammable fiber, synthetic fibers such as PET fibers, nylon fibers, natural fibers such as cotton, jute (jute), and the like, carbon fibers, cellulose nanofibers, and the like can be listed.

[0042] By using bio-derived resins in various components, even if the final process involves incineration (heat recovery), it can be considered "renewable," thus becoming a "sustainable" treatment method. Examples of components using bio-derived resins include: central tubes, supply-side flow path materials, permeate-side flow path materials, separation membranes, end components, and outer covering materials.

[0043] Furthermore, in the case of material recycling and chemical recycling, using PET resin or the like as the central tube, which is made of the same material as the separation membrane (non-woven fabric) and the permeable side flow path material, is expected to facilitate recycling. Therefore, PET resin or the like is also preferred as the supply side flow path material.

[0044] (spiral membrane element)

[0045] For example, Figure 2A As shown, the spiral membrane element E that is the object can be any spiral membrane element that includes a perforated central tube 5 and a winding body R, and the winding body R includes a plurality of membrane sheets L wound on the central tube 5 and having a permeable side flow path inside. Any known spiral membrane element E can be used.

[0046] For example, Figure 2A As shown, the membrane element E generally includes multiple membrane sheets L that sandwich the permeate-side flow path material 3 between opposing separation membranes 1, a supply-side flow path material 2 sandwiched between the membrane sheets L, a perforated central tube 5 that winds the membrane sheets L and the supply-side flow path material 2, and a sealing portion to prevent the supply-side flow path from mixing with the permeate-side flow path. In this case, the permeate-side flow path within the membrane sheet L can be formed by the permeate-side flow path material 3 (also called the permeate-side spacer). In addition, in most cases, an outer covering material (not shown) is provided on the outer periphery of the winding body R.

[0047] Alternatively, a supply-side flow path and / or a permeate-side flow path can be formed on the surface of the separation membrane 1 by providing irregularities or grooves. In this case, the supply-side flow path material 2 and / or the permeate-side flow path material 3 can be omitted.

[0048] exist Figure 2A The diagram shows an example where the sealing portion includes end sealing portions 11 and an outer peripheral sealing portion 12. For example... Figure 2B As shown, in the sealing section, the two-end sealing section 11 is a sealing section obtained by sealing the two ends of the diaphragm L in the axial direction A1 using an adhesive. The outer peripheral sealing section 12 is a sealing section obtained by sealing the end of the outer peripheral front end of the diaphragm L using an adhesive. The area surrounded by the opposing separation membrane 1, the two-end sealing section 11 and the outer peripheral sealing section 12 forms a permeable flow path, and the permeable flow path is connected to the opening 5a of the central tube 5.

[0049] In addition, in the present application, as shown in Figure 2A the center tube 5 and the base end portion of the membrane L are sealed by using an adhesive. In this example, there is the wound body R in which the membrane L and the feed side flow path material 2 are wound on the center tube 5 with the central side seal portion 13 interposed therebetween. Note that the adhesive is not particularly limited, and any of the conventionally known adhesives such as urethane-based adhesives, epoxy-based adhesives, and the like can be used.

[0050] In a general membrane element E, an upstream side end member such as a seal holder is provided on the upstream side of the wound body R, and a downstream side end member such as an anti-stretch material is provided on the downstream side (both not shown). These upstream side end member and downstream side end member are integrated with the wound body R by winding FRP as an outer cover material on the outer periphery of the wound body R.

[0051] In a general spiral-type membrane element having a diameter of 8 inches, about 15 to about 30 sets of the membrane L are wound. When the membrane element E is used, the membrane element E is housed in a pressure vessel (vessel), and a feed liquid is supplied from one end surface side of the membrane element. The supplied feed liquid flows along the feed side flow path material 2 in a direction parallel to the axial direction Al of the center tube 5, and is discharged as a concentrate from the other end surface side of the membrane element. In addition, during the flow of the feed liquid along the feed side flow path material 2, the permeate that has permeated the separation membrane 1 flows along the permeate side flow path material 3, and then flows into the inside of the center tube 5 from the opening 5a, and is discharged from the end portion of the center tube 5.

[0052] The feed side flow path material 2 generally has a function of securing a gap for uniformly supplying a fluid to the membrane surface. Such a feed side flow path material 2 can be, for example, a mesh, a woven fabric, a concave-convex processed sheet, or the like, and a material having a maximum thickness of about 0.1 mm to about 3 mm can be appropriately used as needed. In addition, the flow path material is provided on both surfaces of the separation membrane 1, but different flow path materials are generally used as the feed side flow path material 2 on the feed liquid side and the permeate side flow path material 3 on the permeate liquid side, respectively. It is preferable that a mesh-like flow path material having a coarse mesh and a thick thickness be used in the feed side flow path material 2, and on the other hand, a flow path material of a fabric or a woven fabric having a fine mesh be used in the permeate side flow path material 3.

[0053] As shown in Figure 2B The center tube 5 can be any of the existing tubes as long as it is a tube having an opening 5a on the periphery of the tube. In general, in the case of use in seawater desalination, wastewater treatment, and the like, the permeated water of the separation membrane 1 flows into the center tube 5 from the opening 5a after flowing in the permeate side flow path formed along the permeate side flow path material 3 interposed between the opposing separation membranes 1, flows in the center tube 5, and is discharged from the end portion.

[0054] In the use for seawater desalination, wastewater treatment, and the like, in the case where an RO membrane, an NF membrane is used, as shown in Figure 2A the permeation side flow path material 3 is provided so as to be sandwiched between the opposing separation membranes 1 in the membrane piece L. With respect to this permeation side flow path material, it is required to support the pressure applied to the membrane from the back surface of the membrane, and to secure the flow path of the permeation liquid.

[0055] In order to secure such a function, it is preferable to form the permeation side flow path material using a warp-knitted fabric, and more preferably a warp-knitted fabric which has undergone resin impregnation reinforcement or fusion treatment after the formation of the knitted fabric.

[0056] As the separation membrane 1, various porous membranes can be used, but a composite semipermeable membrane having a separation function layer on the surface of a porous support is preferable. As the porous support, a porous support having a polymer porous layer on one surface of a nonwoven fabric layer is preferable.

[0057] Such a composite semipermeable membrane is referred to as an RO (reverse osmosis) membrane, an NF (nanofiltration) membrane, an FO (forward osmosis) membrane depending on the filtration performance or the treatment method, and can be used for ultrapure water production, seawater desalination, desalination treatment of brine, reuse treatment of wastewater, and the like.

[0058] As the outer layer covering material, various sheets, films, tapes, and the like can be listed, and a fiber reinforced resin (FRP) or the like can be used as needed for reinforcement. In a structure in which the ATD is firmly integrated by covering the FRP on the outer layer, disassembly of the membrane element E and the like is difficult, but in the present application, the internal moisture can be effectively removed without disassembly and the like.

[0059] (First Embodiment)

[0060] In the first embodiment, when a centrifugal force is applied, the axis direction of the above-described spiral type membrane element is arranged substantially in parallel with the direction of the centrifugal force. For example, using a dewatering device as shown in Figure 1A and Figure 1B , it is possible to apply a centrifugal force substantially in parallel with the axis direction Al and the direction A3 of the centrifugal force.

[0061] In the first embodiment, as the opening, an end surface opening formed by a cut surface 16 provided at the end portion of the side on which the centrifugal force is large of the membrane element E is preferable. In the illustrated example, the cut surface 16 is provided only at the end portion of the side on which the centrifugal force is large, but the cut surface 16 can also be provided at the end portion of the side on which the centrifugal force is small. The end surface opening along the spiral shape of the membrane piece L is formed by the cut surface 16. In the expanded view of Figure 2B , such an end surface opening corresponds to the cut lines Cl, C2, and the end surface opening becomes a state in which the permeation side flow path material (that is, the permeation side flow path) sandwiched between the opposing separation membranes 1 is exposed.

[0062] In Figure 1A and Figure 1B In the example shown, the cutting surface 16 is provided only at the end on the side where the centrifugal force is large, and the openings are all arranged at positions where the centrifugal force is larger than the position of the center of gravity G of the membrane element E in the dry state when the centrifugal force is applied.

[0063] Figure 1A and Figure 1B In the dewatering device shown, the rotation shaft 22 is rotated by the rotation driving mechanism 21, and the rotation support portion 24 fixed to the rotation shaft 22 rotates in the direction of the arrow A2. In the example shown, the rotation support portion 24 is composed of two layers, but the rotation support portion 24 can also be composed of one layer, or more rotation support portions 24 can also be provided.

[0064] The rotation support portion 24 has the shaft fixing portion 23 that fixes the rotation shaft 22, and the inner side holding portion 25 and the outer side holding portion 26 that hold the membrane element E. The detailed structure of the inner side holding portion 25 and the outer side holding portion 26 is shown in Figure 3A and Figure 3B

[0065] As shown in Figure 3A , the outer side holding portion 26 arranged on the outer side with respect to the direction A3 of the centrifugal force has a hole portion that fixes the insertion member 29 by screw engagement or the like, and by being inserted into the center pipe 5 when the insertion member 29 is screw engaged or the like, the center pipe 5 can be held. The insertion member 29 preferably has a through hole for the passage of air or moisture.

[0066] The state becomes one in which the center pipe 5 and the winding body R of the membrane element E are press-contacted to the outer side holding portion 26 due to the centrifugal force. In the case where the surface of the press-contacted outer side holding portion 26 is flat, the moisture flowing in the direction A3 of the centrifugal force easily stagnates near the surface of the outer side holding portion 26, and therefore, as shown in Figure 3B , a groove 26a arranged toward the outer side is preferably provided on the inner side surface of the outer side holding portion 26. The groove 26a can be provided in at least one, and preferably three or more.

[0067] In addition, as shown in Figure 3A , the inner side holding portion 25 arranged on the inner side with respect to the direction A3 of the centrifugal force has a hole portion that inserts the insertion member 28, and by being inserted into the center pipe 5 when the insertion member 28 is inserted, the center pipe 5 can be held. The insertion member 28 preferably has a through hole for the passage of air or moisture.

[0068] ​Therefore, in a state where the membrane element E is arranged between the inner holding portion 25 and the outer holding portion 26, by inserting, fixing, or the like of the inner and outer insertion members 28, 29, the center tube 5 of the membrane element E can be held on the rotation support portion 24. As such, in the present application, it is preferable that the center tube 5 be held by the holding mechanism when a centrifugal force is applied.

[0069] As shown in Figure 1A and Figure 1B , the peripheral wall 27a of the container 27 is arranged at an interval on the outer side of the rotation support portion 24. This peripheral wall 27a can catch the moisture discharged in the direction A3 of the centrifugal force, and make it fall to the bottom surface of the base portion 27b of the container 27, and be discharged from the discharge port 27c provided on the base portion 27b. A lid (omitted from illustration) is normally provided on the container 27. Also, in the example illustrated, the rotation drive mechanism 21 is provided on the upper side of the base portion 27b of the container 27, but it is also possible to provide the rotation drive mechanism 21 on the lower side of the base portion 27b in a manner that the rotation shaft 22 penetrates therethrough.

[0070] In the dehydration device illustrated in Figure 1A and Figure 1B , a centrifugal force is generated in the direction A3 by rotation of the rotation support portion 24. As shown in Figure 3A , by the centrifugal force, the moisture present in the permeation-side flow path and the supply-side flow path flows in the direction A6. Since the supply-side flow path is open at the cutting surface 16, the moisture present in the supply-side flow path is discharged from the membrane element E in the direction A6. The moisture present in the permeation-side flow path is discharged from the end surface formed by the cutting surface 16 in the direction A6. In the case where the moisture present in the permeation-side flow path and the supply-side flow path flows in the direction A6 and reaches the outer holding portion 26, it flows in the direction A5 along the groove 26a and is discharged.

[0071] In the example illustrated in Figure 3A , since the cutting surface 16 is present only at one end portion of the membrane element E, air is less likely to flow into the permeation-side flow path compared to the case where the cutting surface 16 is also provided at the other end portion of the membrane element E. However, in the example illustrated in Figure 3A , since the holding mechanism including the inner holding portion 25 and the insertion member 28 has a through-hole that communicates the outside and the center tube 5, air can be supplied from this through-hole into the permeation-side flow path via the center tube 5, the opening 5a, as indicated by the dotted arrow A4. Therefore, the moisture present in the permeation-side flow path can be effectively removed.

[0072] Note that since the holding mechanism including the outer holding portion 26 and the insertion member 29 also has a through-hole that communicates the outside and the center tube 5, the moisture can be discharged from the through-hole as indicated by the arrow A7, or air can flow in from the outside via the through-hole.

[0073] That is, in the present application, it is preferable that the holding mechanism of the membrane element E has a member inserted into the center pipe 5, and the member has a through-hole.

[0074] (Second Embodiment)

[0075] In the second embodiment, the axial direction of the spiral membrane element is arranged obliquely with respect to the direction of the centrifugal force when the centrifugal force is applied. For example, using the dewatering device shown in Figure 4 , it is possible to apply a centrifugal force in which the axial direction Al and the direction A3 of the centrifugal force are in an oblique relationship.

[0076] In the second embodiment, as in the first embodiment, as the opening, it is preferable to include an end face opening formed by a cut surface 16 provided at the end portion on the side where the centrifugal force is large of the membrane element E. In the example shown, the cut surface 16 is provided only at the end portion on the side where the centrifugal force is large, but the cut surface 16 can also be provided at the end portion on the side where the centrifugal force is small. The end face opening along the spiral shape of the membrane sheet L is formed by the cut surface 16.

[0077] In the example shown, the cut surface 16 is provided only at the end portion on the side where the centrifugal force is large, and the openings are all arranged at a position where the centrifugal force is larger than the position of the center of gravity G of the membrane element E in the dry state when the centrifugal force is applied. However, depending on the angle formed by the axial direction Al and the direction A3 of the centrifugal force, sometimes it becomes a state in which more than 80% of the openings are arranged at a position where the centrifugal force is larger than the center of gravity position G.

[0078] Figure 4 In the dewatering device shown in , the rotation shaft 22 is rotated by the rotation driving mechanism 21, and the rotation support portion 24 fixed to the rotation shaft 22 is rotated. The rotation support portion 24 includes a disc portion 24a and a conical frustum inclined portion 24b, and can also be a structure obtained by connecting the conical frustum inclined portion 24b with a radial portion instead of the disc portion 24a. The rotation shaft 22 is fixed to these disc portions 24a and the like.

[0079] The conical frustum inclined portion 24b has an inner side holding portion 25 and an outer side holding portion 26 for holding the membrane element E. The detailed structure of the inner side holding portion 25 and the outer side holding portion 26 can adopt the same structure as the first embodiment shown in Figure 3A and Figure 3B .

[0080] In the second embodiment, it is also preferable that the dewatering device has the same container 27 as the first embodiment shown in Figure 1A and Figure 1B .

[0081] In the second embodiment, as in the first embodiment, it is preferable that the dewatering device has the same rotation driving mechanism 21 as the first embodiment shown in Figure 4In the dehydration apparatus shown, centrifugal force is generated in direction A3 by the rotation of the rotary support 24. Due to this centrifugal force, water present in the permeate side flow path and the supply side flow path flows in the direction A3, simultaneously flowing along both paths. Since the supply side flow path has an opening on the cut surface 16, the water flowing along it is discharged to the outside of the membrane element E through this opening. The water flowing along the permeate side flow path is discharged from the end face opening formed by the cut surface 16. Upon reaching the outer holding portion 26, the water flowing along the permeate side flow path and the supply side flow path flows along the groove 26a and is discharged.

[0082] In the second embodiment, when using Figure 3A In the case of the holding method shown, since the cut surface 16 is only present at one end of the membrane element E, air is less likely to flow into the permeate side flow path compared to the case where the cut surface 16 is also provided at the other end of the membrane element E. However, in Figure 3A In the example shown, since the retaining mechanism, which includes the inner retaining part 25 and the embedded member 28, has a through hole that connects the outside and the central tube 5, air can be supplied from this through hole through the central tube 5 and the opening 5a to the permeable side flow path, as shown by the dashed arrow A4. Therefore, moisture present in the permeable side flow path can be effectively removed.

[0083] It should be noted that since the retaining mechanism, which includes the outer retaining part 26 and the embedded member 29, also has a through hole that connects the outside and the central tube 5, moisture can be discharged from the through hole as shown by arrow A7, or air can flow in from the outside through the through hole.

[0084] (Third Implementation)

[0085] In the third embodiment, when centrifugal force is applied, the axial direction of the spiral membrane element is arranged substantially perpendicular to the direction of the centrifugal force. For example, using... Figure 5A The dehydration device shown can apply centrifugal force with the axial direction A1 and the centrifugal force direction A3 being basically perpendicular.

[0086] In the third embodiment, such as Figure 5B As shown, the opening preferably includes a segmented opening, which is formed by a cutting slit 17 provided from the outer periphery of the membrane element E on the side with greater centrifugal force toward the central tube 5.

[0087] In the illustrated example, a cutting slit 17 is formed along the entire length of the end member containing the membrane element E, but the length of the cutting slit 17 is preferably 50% or more, more preferably 80% or more, and most preferably the entire length, relative to the entire length.

[0088] Further, the cutting slit 17 is formed up to a depth reaching the center tube 5 of the membrane element E, but the depth of the cutting slit 17 is preferably 50% or more, more preferably 80% or more, and most preferably 100% with respect to the thickness of the winding body R in the radial direction. Further, the depth of the cutting slit 17 can not be constant. Note that in the second embodiment, depending on the inclination angle, only such a cutting slit 17 can be provided, or a cutting slit 17 and a cutting face 16 of the end portion can be provided.

[0089] As the position where the cutting slit 17 is formed, it is sufficient that it is the outer peripheral portion on the side where the centrifugal force is greater compared to the center of gravity position G of the membrane element E, but it is preferably provided at the outer peripheral portion of the position where the centrifugal force is the greatest.

[0090] In the illustrated example, the direction of the cutting face of the cutting slit 17 is parallel to the radial direction, but it can also be parallel to the axial direction Al, and it can also be formed so as to be inclined with respect to the axial direction Al.

[0091] Figure 5A In the illustrated dehydration device, the rotation shaft 22 is rotated by the rotation drive mechanism 21, and the rotation support portion 24 fixed to the rotation shaft 22 is rotated. The rotation support portion 24 includes a disc portion 24a and a cylindrical portion 24c, and can also be a structure in which the cylindrical portion 24c is connected by a radial portion instead of the disc portion 24a. The rotation shaft 22 is fixed to these disc portions 24a and the like.

[0092] The cylindrical portion 24c has an upper side holding portion 31 and a lower side holding portion 32 for holding the membrane element E. The upper side holding portion 31 and the lower side holding portion 32 can be the same structure as the inner side holding portion 25 or the outer side holding portion 26. In the third embodiment, it is also preferable that the dehydration device have a container 27 as in the first embodiment. Figure 1A and Figure 1B the first embodiment.

[0093] In the dehydration device illustrated in Figure 5A In the dehydration device illustrated in

[0094] In the third embodiment, as in the first embodiment, the cutting slit 17 is formed in the outer peripheral portion of the membrane element E, and the cutting face of the cutting slit 17 is parallel to the radial direction. Further, the cutting slit 17 is formed up to a depth reaching the center tube 5 of the membrane element E, but the depth of the cutting slit 17 is preferably 50% or more, more preferably 80% or more, and most preferably 100% with respect to the thickness of the winding body R in the radial direction. Further, the depth of the cutting slit 17 can not be constant. Note that in the second embodiment, depending on the inclination angle, only such a cutting slit 17 can be provided, or a cutting slit 17 and a cutting face 16 of the end portion can be provided. Figure 5BAs shown, as the opening, only the partition surface opening exists on the side where the centrifugal force of the membrane element E is large, and thus air is not easily introduced into the permeation side flow path. Therefore, in order to introduce air into the permeation side flow path, it is preferable to provide another cutting slit 17 or a hole from the outer peripheral portion of the side where the centrifugal force of the membrane element E is small toward the center pipe 5, and from the viewpoint of easily maintaining the shape of the membrane element E, it is more preferable to provide a hole from the outer peripheral portion toward the center pipe 5.

[0095] (Other embodiments of the holding mechanism of the membrane element)

[0096] (1) In the above-described embodiments, an example of the holding mechanism that holds the membrane element E by fixing the inner holding portion 25 and the outer holding portion 26 to the rotation support portion 24, and providing the insertion members 28, 29 to the inner holding portion 25 and the outer holding portion 26, is shown, but a different holding mechanism can be employed in the present application.

[0097] For example, a holding mechanism can be configured in which the inner holding portion 25 that is obtained by integrating the insertion member 28 or the outer holding portion 26 that is obtained by integrating the insertion member 29 is made movable, and the membrane element E is held by changing the distance between the two. At this time, an elastic body or the like can be used to enable movement and restoration of the membrane element E from the held position.

[0098] (2) In the above-described embodiments, an example of the holding mechanism that holds the membrane element E by inserting the insertion members 28, 29 of the holding mechanism into the center pipe 5 is shown, but a holding mechanism that holds the membrane element E by gripping the outer periphery or the like of the center pipe 5 instead of such an insertion member 28 or insertion member 29 can also be used.

[0099] (3) In the above-described embodiments, an example of the holding mechanism that holds the membrane element E by fixing the center pipe 5 is shown, but a holding mechanism that accommodates and holds each membrane element E in a cylindrical container can also be used.

[0100] Industrial applicability

[0101] According to the present application, since the moisture of the membrane element after dehydration is sufficiently removed, it is advantageous to perform various recycling or landfill treatment. In particular, in the case of performing heat recycling that is effective use of process fuels such as papermaking plants, metal smelting, cement manufacturing, it is possible to improve the quality and value as fuel. Specifically, in the case of using the membrane element as RPF (Refuse paper and plastic fuel) fuel, it is possible to relatively increase the heat generated at the time of incineration.

[0102] Explanation of reference numerals

[0103] 1: separation membrane

[0104] 2: supply-side flow path material

[0105] 3: permeation-side flow path material

[0106] 5: center tube

[0107] 16: cutting surface

[0108] 17: cutting slit

[0109] A1: axial direction

[0110] A3: direction of centrifugal force

[0111] E: spiral membrane element

[0112] R: roll body

[0113] L: membrane sheet

[0114] G: center of gravity position

Claims

1. A method for dehydrating a spiral membrane element, the method for dehydrating a spiral membrane element reducing moisture contained in a used spiral membrane element, wherein the spiral membrane element has a winding body and a perforated center tube, the winding body including a plurality of membrane sheets wound on the center tube and having a permeation-side flow path inside, the method for dehydrating a spiral membrane element includes the following steps: a step of forming an opening on the plurality of membrane sheets that communicates the permeation-side flow path with the outside; and a step of applying a centrifugal force to the spiral membrane element on which the opening is formed, at least a part of the opening is disposed at a position where the centrifugal force is greater than a position of a center of gravity of the spiral membrane element in a dry state when the centrifugal force is applied.

3. The method for dehydrating a spiral membrane element according to claim 1, wherein the spiral membrane element is disposed with an axial direction thereof substantially parallel to a direction of the centrifugal force when the centrifugal force is applied, and the opening includes an end face opening formed by a cut surface provided at an end portion of a side of the spiral membrane element where the centrifugal force is greater.

4. The method for dehydrating a spiral membrane element according to claim 1, wherein the spiral membrane element is disposed with an axial direction thereof inclined with respect to a direction of the centrifugal force when the centrifugal force is applied, and the opening includes an end face opening formed by a cut surface provided at an end portion of a side of the spiral membrane element where the centrifugal force is greater.

5. The method for dehydrating a spiral membrane element according to any one of claims 1 to 3, wherein the spiral membrane element is disposed with an axial direction thereof substantially perpendicular to a direction of the centrifugal force when the centrifugal force is applied, and the opening includes a split face opening formed by a cut slit provided from an outer peripheral portion of a side of the spiral membrane element where the centrifugal force is greater toward the center tube.

1. A method for dehydrating a spiral membrane element, the method for dehydrating a spiral membrane element reducing moisture contained in a used spiral membrane element, wherein the spiral membrane element has a winding body and a perforated center tube, the winding body including a plurality of membrane sheets wound on the center tube and having a permeation-side flow path inside, the method for dehydrating a spiral membrane element includes the following steps: a step of forming an opening on the plurality of membrane sheets that communicates the permeation-side flow path with the outside; and a step of applying a centrifugal force to the spiral membrane element on which the opening is formed, at least a part of the opening is disposed at a position where the centrifugal force is greater than a position of a center of gravity of the spiral membrane element in a dry state when the centrifugal force is applied.

3. The method for dehydrating a spiral membrane element according to claim 1, wherein the spiral membrane element is disposed with an axial direction thereof substantially parallel to a direction of the centrifugal force when the centrifugal force is applied, and the opening includes an end face opening formed by a cut surface provided at an end portion of a side of the spiral membrane element where the centrifugal force is greater.

2. The dewatering method of a spiral membrane element according to claim 1, wherein, The centrifugal acceleration at the portion of the spiral membrane element where the centrifugal force is the greatest is 50 G (490 m / s 2 ) or more.

4. The method for dehydrating a spiral membrane element according to claim 1, wherein the spiral membrane element is disposed with an axial direction thereof inclined with respect to a direction of the centrifugal force when the centrifugal force is applied, and the opening includes an end face opening formed by a cut surface provided at an end portion of a side of the spiral membrane element where the centrifugal force is greater.

5. The method for dehydrating a spiral membrane element according to any one of claims 1 to 3, wherein the spiral membrane element is disposed with an axial direction thereof substantially perpendicular to a direction of the centrifugal force when the centrifugal force is applied, and the opening includes a split face opening formed by a cut slit provided from an outer peripheral portion of a side of the spiral membrane element where the centrifugal force is greater toward the center tube. ​ ​ ​ ​ ​ ​ ​

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