JP6532363B2 - Separation membrane structure and separation membrane structure module - Google Patents

Description

  The present invention relates to a separation membrane structure comprising a separation membrane.

  In a separation membrane structure comprising a columnar base having a porous structure and a separation membrane formed on the inner wall of a flow path parallel to the longitudinal direction of the base, the end face of the base is covered with a glass seal layer (See, for example, Patent Document 1).

JP, 2012-176367, A

  When the fluid to be treated is treated by the cross flow method using the separation membrane structure, the fluid to be treated is introduced into the separation membrane structure from the inlet end surface of the separation membrane structure, and flows through the flow path. The base material permeates through the base material and is discharged as filtrate from the outer peripheral surface, and is discharged as concentrate from the outlet side end face of the separation membrane structure. As described above, when the separation membrane structure is used in the cross flow method, the pressure in the flow path is higher and the transmembrane pressure difference is higher as the separation membrane structure is closer to the inlet of the separation membrane structure. In the vicinity of the inlet of the structure, there has been a problem that membrane separation (clogging) of the separation membrane is likely to occur due to the residue of the fluid to be treated.

  The present invention was made in order to solve the above-mentioned subject, and can be realized as the following modes.

(1) According to one aspect of the present invention, a separation membrane structure is provided. This separation membrane structure is a porous inorganic material provided with a first end face in the longitudinal direction, a second end face, an outer peripheral surface, and a flow path communicating the first end face and the second end face. The outer peripheral seal layer is provided with a base made of a material, a separation membrane formed on the inner wall of the flow passage, and an outer peripheral seal layer formed on at least a part of the outer peripheral surface of the base The area of the first end face side is larger than the area of the second end face side with the bisector of the length in the longitudinal direction of the base material as a boundary. According to the separation membrane structure of this aspect, the outer membrane sealing layer prevents discharge of the filtrate from the outer peripheral face on the first end face side, thereby reducing the inter-membrane differential pressure of the first end face side separation membrane. be able to. Therefore, excessive separation is suppressed by the separation membrane on the first end face side, and the frequency of separation can be made to approach equally in the separation membranes of each part in the longitudinal direction. For this reason, stable separation as a separation membrane structure becomes possible.

(2) In the separation membrane structure of the above aspect, the first end face may be an inlet side into which the fluid to be treated flows. In this way, membrane blockage of the separation membrane on the inlet side of the separation membrane structure can be suppressed, and separation on the outlet side (second end face side) can be performed to the same extent as on the inlet side. As a membrane structure, stable separation is possible.

(3) In the separation membrane structure of the above aspect, the first end face seal layer formed on the first end face of the base and the second end face seal layer formed on the second end face are further formed The outer peripheral surface sealing layer may extend from at least one of the first end surface sealing layer and the second end surface sealing layer. Thus, at least one of the first end face seal layer and the second end face seal layer (hereinafter, the first end face seal layer and the second end face seal layer are collectively referred to simply as the end face seal layer) Since the outer peripheral seal layer can be integrally formed at the time of formation, the outer peripheral seal layer can be formed simultaneously with the end face seal layer. Therefore, the outer peripheral seal layer can be easily formed.

(4) In the separation membrane structure of the above aspect, the outer peripheral surface sealing layer may be divided into two or more regions. Also in this case, the transmembrane differential pressure of the separation membrane can be adjusted to suppress clogging of the separation membrane, and stable separation as a separation membrane structure can be achieved.

(5) According to one aspect of the present invention, a separation membrane structure module is provided. The separation membrane structure module includes the separation membrane structure of the above-described embodiment, and a housing that houses the separation membrane structure. According to this separation membrane structure module, since the membrane blockage of the separation membrane on the first end face side is suppressed, stable separation becomes possible. In addition, the membrane clogging which is biased by the separation membrane on the first end face side is suppressed, the number of times of cleaning of the separation membrane of the separation membrane structure module can be reduced, and the convenience is improved. In addition, since the number of times of cleaning of the separation membrane can be reduced, man-hour and time required for the cleaning can be suppressed, and the processing efficiency as a whole can be improved. In addition, the cost for cleaning can be reduced.

(6) In the separation membrane structure module of the above aspect, the separation membrane structure may be stored in the housing via a seal member made of an elastic material.

  The present invention can be realized in various forms, for example, an apparatus provided with a separation membrane structure, a method of manufacturing a separation membrane structure, a method of manufacturing a separation membrane structure module, etc. Can.

It is a cutting part end elevation showing typically the structure of the separation membrane structure module as an embodiment of the present invention. It is an explanatory view showing the appearance of the separation membrane structure. It is explanatory drawing which shows the external appearance of a base material. It is explanatory drawing which shows the external appearance of the separation-membrane structure of a comparative example. It is explanatory drawing for demonstrating the transmembrane pressure difference in a separation-membrane structure. It is a schematic diagram which shows typically the external appearance of the separation-membrane structure of a modification.

A. Embodiment:
A-1. Structure of separation membrane structure module:
FIG. 1: is a cutting part end view which shows typically the structure of the separation-membrane structure module 100 as embodiment of this invention. FIG. 1 illustrates a cut surface including a central axis along the longitudinal direction of the separation membrane structure 20 formed in a substantially cylindrical shape. The separation membrane structure module 100 mainly includes the separation membrane structure 20 and the housing 30, and is configured to be able to process the liquid to be processed by the cross flow method. The separation membrane structure 20 is supported by the housing 30 via the O-rings 37 and 38, the metal blocking members 35 and 36, and the O-rings 39 and 40, and is accommodated in the housing 30. The O-rings 37 and 38 in the present embodiment correspond to the seal members in the claims.

  FIG. 2 is an explanatory view showing the appearance of the separation membrane structure. In FIG. 2, O-rings 37 and 38 used when storing the separation membrane structure 20 in the housing 30 are illustrated by broken lines. The separation membrane structure 20 has a substantially cylindrical outer shape, and a plurality of through holes penetrating from one end face (first structure end face 28F) to the other end face (second structure end face 28S) (Channel 26) is formed.

  As shown in FIG. 1, the separation membrane structure 20 includes a base material 22, a separation membrane 24, a first end face seal layer 281, a second end face seal layer 282, and a first outer peripheral face seal layer 291. , And the second outer peripheral seal layer 292. Hereinafter, the first end face seal layer 281 and the second end face seal layer 282 will be collectively referred to as an end face seal layer 28, and the first outer peripheral face seal layer 291 and the second outer peripheral face seal layer 292 will be collectively Also referred to as face seal layer 29. The end face seal layer 28 and the outer peripheral surface seal layer 29 will be described in detail later.

  FIG. 3 is an explanatory view showing the appearance of the base material. As shown in FIG. 3, the base material 22 is made of alumina having a circular first end face 221, a second end face 222, and an outer peripheral surface 223, and is formed in a cylindrical shape having a total length of about 1000 mm. It is a porous body. A so-called monolith in which a plurality of channels 26 are formed in the base material 22 so as to communicate the first end surface 221 and the second end surface 222 and through which the liquid to be treated treated by the separation membrane structure 20 flows. It is a porous body.

  The separation membrane 24 is a porous membrane made of alumina provided with a large number of fine pores having a smaller average pore size than the base material 22. The separation membrane 24 is formed on the surface of the flow path 26 formed in the base material 22 (FIG. 1).

  As shown in FIG. 2, the first end face seal layer 281 is formed on the first end face 221 (FIG. 3) of the base material 22 and covers the entire first end face 221. Furthermore, the first end face seal layer 281 is also formed on a part of the inner surface of the separation membrane 24 continuously from the first end face 221 of the base material 22 as illustrated in the partial enlarged view of FIG. It is done.

  The second end face seal layer 282 is formed on the second end face 222 (FIG. 3) of the base material 22 and covers the entire second end face 222. Furthermore, the second end face seal layer 282 is also formed on a part of the inner surface of the separation membrane 24 continuously from the second end face 222 of the base material 22 as illustrated in the partial enlarged view of FIG. It is done.

  The first outer peripheral seal layer 291 and the second outer peripheral seal layer 292 are formed on a part of the outer peripheral surface 223 (FIG. 3) of the base material 22. In the outer peripheral surface sealing layer 29, the area on the first end face 221 side is larger than the area on the second end face 222 side with the bisector CL of the length of the base material 22 in the longitudinal direction as a boundary. Specifically, the first outer peripheral surface sealing layer 291 has a length in the longitudinal direction of the base material 22 from the end on the first end face 221 side of the outer peripheral surface 223 of the base material 22 toward the second end face 222 It is formed to cover the outer peripheral surface 223 (FIG. 3) of the base material 22 beyond the dividing line CL to a position of 785 mm from the end on the first end face 221 side. The second outer peripheral surface sealing layer 292 covers the outer peripheral surface 223 of the base 22 from the end on the second end surface 222 side of the outer peripheral surface 223 of the base 22 toward the first end surface 221 to a position of 15 mm. It is formed as. That is, in the outer peripheral surface 223 of the base material 22, an area of 200 mm from the position of 785 mm from the end on the first end face 221 side is the non-coated area 224 where the outer peripheral surface sealing layer 29 is not formed. In the present embodiment, the first outer peripheral seal layer 291 extends from the first end seal layer 281, and the second outer peripheral seal layer 292 extends from the second end seal layer 282. There is. Further, in the present embodiment, the end face seal layer 28 and the outer peripheral surface seal layer 29 are formed of glass.

  The housing 30 is a hollow metal container having a space for accommodating the separation membrane structure 20 therein, and as shown in FIG. 1, an inlet 31 for introducing a liquid to be treated, and the separation membrane structure 20. Concentrated solution from which the liquid to be treated is concentrated is discharged by the first filtrate port 33, the second filtrate port 34, and the separation membrane structure 20, which flow out the filtrate filtered by And an outlet 32. In the separation membrane structure 20, an annular metal blocking member 35 is fitted through an O-ring 37 disposed on the vicinity of the first structure end face 28F of the first outer peripheral surface sealing layer 291, and the second An annular metal blocking member 36 is fitted through an O-ring 38 disposed on the outer peripheral seal layer 292. The separation membrane structure 20 is supported and accommodated in the housing 30 via the O-rings 39 and 40 between the inner wall of the housing 30 and the metal blocking members 35 and 36. As described above, since the separation membrane structure 20 is housed in the housing 30, the first space S1, in which the space in the housing 30 is surrounded by the first structure end face 28F and the inner wall of the housing 30, The second space S2 surrounded by the outer peripheral surface 223 (including the region where the first outer peripheral surface seal layer 291 is formed) and the inner wall of the housing 30, the second structure end surface 28S and the inner wall of the housing 30 Each of the third spaces S3 is divided to maintain sealing. Note that the second outer peripheral surface sealing layer 292 is formed to a little beyond the position where the O-ring 38 is formed (FIG. 2), and when the separation membrane structure 20 is accommodated in the housing 30, The second outer peripheral seal layer 292 hardly contacts the second space S2 (FIG. 1).

  As described above, the separation membrane structure module 100 can be used to treat the liquid to be treated in a cross flow manner. When the liquid to be treated is introduced from the inlet 31 into the first space in the housing 30, the liquid to be treated enters the separation membrane structure 20 from the side of the first end face 221 of the separation membrane structure 20 and flows While flowing through the passage 26, only the components that can pass through the separation membrane 24 pass through the separation membrane 24 and the base material 22 and flow out to the second space S2, and the first filtrate port 33, as a filtrate, It flows out of the second filtrate port 34. The liquid to be treated is concentrated by the separation membrane structure 20 and flows out to the third space S3, and is discharged from the concentrated liquid discharge port 32 as a concentrated liquid.

  In the separation membrane structure 20 of the present embodiment, since the first outer peripheral surface sealing layer 291 is formed on a part of the outer peripheral surface 223 of the base material 22, as shown in FIG. The liquid to be treated (filtrate) is not discharged from the area where the first outer peripheral surface sealing layer 291 is formed on the outer peripheral surface 223 of the base material 22, but flows through the base material 22. Is discharged from the uncovered area 224 of the second space S2. Therefore, as will be described in detail later, in the separation film 24, the transmembrane pressure difference can be reduced in the region corresponding to the first outer peripheral seal layer 291. On the other hand, the second outer peripheral seal layer 292 hardly contacts the second space S2 as described above. Therefore, the second outer peripheral seal layer 292 does not contribute to the adjustment of the transmembrane pressure difference. That is, the second outer peripheral seal layer 292 does not contribute to the adjustment of the filtration amount of the liquid to be treated described later. In the second outer peripheral seal layer 292, the portion in contact with the second space S2 does not contribute to the adjustment of the transmembrane pressure difference. In that sense, the “second outer peripheral seal layer 292 In the space of "I hardly touch" is described. The second outer peripheral seal layer 292 may not be in contact with the second space S2.

  The first end face 221 and the second end face 222 of the substrate 22 are covered with the first end face seal layer 281 and the second end face seal layer 282, so the liquid to be treated passes through the separation membrane 24. In addition, it is suppressed that the processing efficiency is lowered by mixing the filtrate passing through only the base material 22 into the filtrate or mixing the filtrate passing through the separation membrane 24 into the concentrate through the base material 22. be able to.

  Further, as shown in FIGS. 1 and 2, the outer peripheral surface sealing layer 29 covers a part of the outer peripheral surface 223 of the base material 22, and a housing is formed on the outer peripheral surface sealing layer 29 via O rings 37 and 38. It is supported in the body 30. Therefore, in the first space, the liquid to be treated enters the base 22 from the outer peripheral surface 223 of the base 22, flows in the base 22 and flows out from the outer peripheral surface 223 to the second space, or a flow path As a result, the filtrate that has passed through the separation membrane 24 is prevented from being discharged from the outer peripheral surface 223 of the base 22 to the third space.

A-2. Evaluation test results:
Using the separation membrane structure 20 (sample 1) of the above embodiment and the separation membrane structure 20P (sample 2) of the comparative example, the membrane blockage suppression effect of the separation membrane 24 by the first outer peripheral surface seal layer 291 is examined The

  FIG. 4 is an explanatory view showing the appearance of the separation membrane structure 20P of the comparative example. In the separation membrane structure 20P of the comparative example, the length in the longitudinal direction of the first outer peripheral surface seal layer 291P (hereinafter simply referred to as the length) is the first outer peripheral surface seal layer of the separation membrane structure 20 of this embodiment. Although shorter than the length in the longitudinal direction of 291, the other configuration is the same as that of the separation membrane structure 20 of the present embodiment. The length of the first outer peripheral seal layer 291P is the same as that of the second outer peripheral seal layer 292P. Since the first outer peripheral seal layer 291P is shorter than the first outer peripheral seal layer 291 of this embodiment and the length of the second outer peripheral seal layer 292P is the same as 292 of this embodiment, The uncoated region 224P on the outer peripheral surface 223 of the base material 22 of the separation membrane structure 20P is longer than the uncoated region 224 in the separation membrane structure 20 of the present embodiment. Below, the detail (the formation area of each outer peripheral surface sealing layer, the length of a non-coating area | region) of each sample and a test method are demonstrated.

<Sample>
Sample 1 In the present embodiment, the separation membrane structure 20:
1000 mm in length
First outer peripheral surface seal layer 291 length from the first end face 221 785 mm
Second outer peripheral surface sealing layer 292 15 mm in length from the second end surface 222
Uncoated area 224 on the outer peripheral surface 223 of the base material 22 Length 200 mm
Sample 2 Comparative Example Separation Membrane Structure 20P:
1000 mm in length
First outer peripheral surface seal layer 291 P 15 mm in length from the first end face 221
Second outer peripheral surface sealing layer 292P 15 mm in length from the second end surface 222
Uncoated area 224P in base material 22 peripheral surface 223 length 970 mm

<Manufacturing method>
Sample 1 Separation membrane structure 20
(1) Leave 15 mm on each end of the outer peripheral surface 223 of the base material 22 on which the separation film 24 is formed, and protect the other parts with a masking tape.
(2) Immersing (1) in the glass glaze slurry to coat both ends 15 mm of the outer peripheral surface 223 of the base material 22.
(3) Dry in a hot air dryer at 80 ° C. for 1 hour.
(4) On the outer peripheral surface of the base material 22, the position from the first end face 221 to 785 mm is used as a starting point, and the position to 985 mm is protected by the masking tape.
(5) The outer peripheral surface of (4) is coated with glass glaze by spray coating. (Since the glass glaze is coated by spray coating, no coating by the glass glaze is formed on the corresponding area of the separation film 24.)
(6) After peeling off the masking tape, firing is performed in a heat treatment furnace at 900 ° C. for 2 hours.
Sample 2 Separation membrane structure 20P:
Steps (1) to (3) and (6) in sample 1 were performed.

<Membrane obstruction evaluation test>
Liquid to be treated: skimmed milk powder solution dissolved at a ratio of 100 g of skimmed milk powder to 1 L of purified water Temperature of the liquid to be treated: 25 ° C.
Linear velocity of liquid to be treated: 2.3 m / s
Each sample was mounted in the housing 30 by the above-described method, and a piping of a circulatory system was introduced to introduce the concentrate and the filtrate discharged from each sample into each sample again. After treating the liquid to be treated by the cross flow method for 2 hours under the above test conditions, each sample is removed from the housing 30 and disassembled, and the surface of the separation membrane 24 is magnified with a magnifying glass (magnification: 10 to 50). It observed visually. As a result, in the separation membrane 24 of the sample 2 (the separation membrane structure 20P of the comparative example), a larger amount of membrane clogging due to solid matter contained in the treatment liquid is observed in the region closer to the upstream side in the flow direction of the treatment liquid. It was confirmed that there were a lot of membrane blockages overall. On the other hand, in the separation membrane 24 of the sample 1 (the separation membrane structure 20 of the present embodiment), no biased membrane blockage on the upstream side in the flow direction of the liquid to be treated is observed. The membrane blockage by the object was significantly reduced relative to the sample 2.

As described above, according to the separation membrane structure 20 of the present embodiment, the membrane blockage of the separation membrane 24 on the upstream side (also referred to as the inlet side) in the flow direction of the liquid to be treated (fluid to be treated) It was suppressed. The reason why the membrane blockage of the separation membrane 24 on the upstream side in the flow direction of the liquid to be treated in the separation membrane structure 20 is suppressed is the outer circumferential face of the separation membrane structure 20 by the first outer circumferential seal layer 291. It is considered that the pressure applied to the separation membrane structure 20 (that is, the separation membrane 24) from the side is increased, and the transmembrane pressure difference of the separation membrane 24 on the upstream side in the flow direction of the liquid to be treated is reduced. Here, the transmembrane pressure difference means the pressure (primary pressure) applied to the separation membrane structure (that is, the separation membrane) by the liquid to be treated, and the separation membrane structure (that is, from the outer peripheral surface side of the separation membrane structure). It represents the difference between the pressure (secondary pressure) applied to the separation membrane). In the separation membrane structure, the filtration amount (separation amount) of the liquid to be treated increases as the location where the transmembrane pressure difference is large.
When the fluid to be treated is treated by the normal cross flow method, the pressure applied by the fluid to be treated to the separation membrane structure (that is, the separation membrane) is higher toward the inlet side of the separation membrane structure due to pressure loss of the treatment fluid. The pressure decreases toward the outlet side. Therefore, in the structure of separation membrane structure 20P of sample 2 which is a comparative example, the pressure applied from the outer peripheral surface side of separation membrane structure 20P is uniform from the upstream side to the downstream side of the flow direction of the fluid to be treated. The transmembrane differential pressure increases as the flow direction of the fluid to be treated flows (ie, the inlet side) increases, and the transmembrane pressure decreases as the flow direction downstream of the fluid to be treated (ie, the outlet side). Therefore, in the sample 2 which is the comparative example, the amount of separation is large on the upstream side in the flow direction of the fluid to be treated, and a biased membrane clogging of the separation membrane 24 occurs.

Hereinafter, the reason why the differential pressure of the separation membrane 24 is reduced in the separation membrane structure 20 of the present embodiment will be described in detail with reference to FIG.
FIG. 5 is an explanatory view for explaining transmembrane differential pressure in the separation membrane structure 20 and the separation membrane structure 20P of the present embodiment. FIG. 5 (A) shows the separation membrane structure 20 of the present embodiment, and FIG. 5 (B) conceptually shows the transmembrane pressure in the separation membrane structure 20P of the comparative example. In FIG. 5, in order to show the correspondence between the formation area of the outer peripheral surface seal layer 29 and the transmembrane differential pressure, a cross section of a part of the separation membrane structure 20 is illustrated. Further, FIG. 5 shows the transmembrane pressure difference in the region where the separation membrane structures 20 and 20P are in contact with the second space S2 (FIG. 1) of the housing 30. This is because the liquid to be treated passes through the separation membrane structures 20 and 20P and is discharged to the second space S2.

  As shown in FIG. 5A, the pressure in the flow path 26 is a pressure loss from the inlet (first structure end face 28F) of the liquid to be treated toward the outlet (second structure end face 28S). It decreases almost linearly. The pressure in the flow path 26 is also referred to as the primary side (to-be-treated fluid side) pressure. On the other hand, the pressure on the filtrate side (also referred to as the secondary side) is atmospheric pressure in the non-covering region 224 (region where the outer peripheral surface sealing layer 29 is not formed), and the region where the outer peripheral surface sealing layer 29 is formed Then it will be higher than atmospheric pressure. Assuming that the direction orthogonal to the central axis in the longitudinal direction of the base material 22 is the filtration direction (downward in the end view of FIG. 5), the filtrate that has permeated the separation membrane 24 in the region where the outer peripheral surface sealing layer 29 is formed. However, since the base material 22 can not permeate in the filtration direction, the filtrate is discharged from the outer peripheral surface 223 to the second space S2 in the non-coated region 224 while flowing in the base material 22 in the longitudinal direction (FIG. 1) . In the region where the outer peripheral surface sealing layer 29 is formed, the filtrate remains in the pores of the base material 22, so the secondary side pressure becomes higher than that in the non-coated region 224. In the region where the first outer peripheral surface seal layer 291 is formed, the pressure is higher toward the inlet side of the liquid to be treated (the first end face 221 side of the base material 22) because the separation membrane 24 permeates the base material. This is because the resistance of the permeated liquid to pass through the pores of the base material 22 becomes higher due to the long distance until the filtrate that enters 22 is discharged from the non-coated region 224 of the outer peripheral surface 223 to the outside. . Thus, the transmembrane pressure difference which is the difference between the primary pressure and the secondary pressure of the separation film 24 becomes smaller in the region where the first outer peripheral seal layer 291 is formed. In the separation membrane structure 20 of the present embodiment, the transmembrane pressure difference of the separation membrane 24 is substantially constant throughout the longitudinal direction.

  On the other hand, in the separation membrane structure 20P of the comparative example (FIG. 5B), since the first outer peripheral seal layer 291P is not formed in the region in contact with the second space, the secondary pressure is It is atmospheric pressure. The pressure in the flow path 26 (primary side pressure) is the same as the separation membrane structure 20 of the present embodiment, from the inlet (first structure end face 28F) of the separation membrane structure 20P to the outlet (second structure) The pressure loss decreases substantially linearly toward the end face 28S). Therefore, the transmembrane differential pressure is largest at the inlet (first structure end face 28F) side of the separation membrane structure 20, and decreases substantially linearly toward the outlet (second structure end face 28S).

  In the separation membrane structure, the filtration amount of the liquid to be treated increases as the transmembrane differential pressure of the separation membrane increases, so the amount of residue also increases and clogging of the separation membrane, that is, membrane clogging tends to occur. In the separation membrane structure 20P of the comparative example, since the transmembrane pressure difference is large in the vicinity of the inlet (the first structure end face 28F), the membrane clogging of the separation membrane 24 tends to occur. On the other hand, in the separation membrane structure 20 of the present embodiment, the first outer peripheral seal layer 291 is formed in the vicinity of the inlet (first structure end face 28F) of the separation membrane structure 20. Since the transmembrane pressure in the vicinity of the inlet (first structure end face 28F) of the body 20 is reduced, the throughput (filtration amount) in the vicinity of the inlet of the separation membrane structure 20 can be reduced. Membrane blockage of the separation membrane 24 can be suppressed. Furthermore, in the separation membrane structure 20 of the present embodiment, the first outer peripheral surface seal across the bisector CL of the base material 22 from the end of the inlet side (first structure end surface 28F) of the outer peripheral surface 223 The layer 291 is formed, and the transmembrane pressure of the separation membrane 24 is substantially constant over the entire longitudinal direction. Therefore, the liquid to be treated can be uniformly separated over the entire longitudinal direction of the separation membrane structure 20, and the membrane blockage of the separation membrane 24 can be suppressed.

  When the liquid to be treated is treated by the cross flow method, the concentrated liquid discharged from the concentrated liquid discharge port 32 is again introduced into the separation membrane structure 20 from the inlet 31 and the liquid to be treated is treated for a predetermined treatment time. There is a case where the process is continued by being circulated. In the separation membrane structure 20 of the present embodiment and the separation membrane structure 20P of the comparative example, per unit time of the separation membrane structure 20 of the present embodiment when the introduction flow rate of the liquid to be treated to the housing 30 is the same. Although the amount of filtrate is smaller than the amount of filtrate per unit time of the separation membrane structure 20P of the comparative example, the membrane clogging of the separation membrane 24 is suppressed. Therefore, in the separation membrane structure 20, the number of times of cleaning the separation membrane 24 can be reduced more than that of the separation membrane structure 20P during a predetermined processing time (for example, 3 to 10 hours), and stable separation Is possible. As a result, according to the separation membrane structure 20 of the present embodiment, the number of steps (time) for cleaning can be suppressed, and the processing efficiency as a whole can be improved. In addition, although the separation membrane structure module 100 is disassembled when the separation membrane 24 is cleaned, the separation membrane structure 20 according to the present embodiment has a reduced number of times of cleaning the separation membrane 24. The time required for cleaning is reduced, and the convenience is improved. In the present embodiment, in the region where the first outer peripheral surface sealing layer 291 is formed, the filtrate that has permeated the corresponding region of the separation membrane 24 flows through the substrate 22 as the processing fluid flows, as described above. Since the fluid is discharged from the non-coated region of the outer peripheral surface 223 of the base material 22 to the second space while flowing in the direction, filtration of the liquid to be treated is performed although the amount of filtration is not large. On the other hand, in the case of the separation membrane structure 20P, if clogging of the separation membrane 24 occurs, filtration is not performed in that region, and the processing capacity is extremely reduced, so that cleaning is necessary.

In order to make the amount of separation substantially uniform over the entire longitudinal direction of the separation membrane structure, it is conceivable to reduce the thickness of the separation membrane from the inlet side to the outlet side (by providing a thickness gradient). . When the separation membrane is formed on the inner surface of the base material flow channel, the flow channel diameter of the separation membrane structure can be made substantially constant over the entire area in the longitudinal direction by decreasing the flow channel diameter from the inlet side to the outlet side. it can. When the separation membrane is formed on the outer surface of the substrate, the outer diameter of the separation membrane structure should be substantially constant over the entire longitudinal direction by increasing the outer diameter of the substrate from the inlet side toward the outlet side. Can. However, it is laborious to form a separation membrane having a thickness gradient, and it is difficult to accurately manufacture a separation membrane having a thickness gradient. Moreover, it is also difficult to form a base material in which the flow path diameter and the outer diameter are provided with a gradient, and it is also difficult to obtain accuracy.
On the other hand, in the separation membrane structure 20 of the present embodiment, the length of the first outer peripheral surface seal layer 291 is made longer to make the amount of separation substantially uniform. As described above, the first outer peripheral surface sealing layer 291 is formed by spray coating a glass glaze after immersion in the glass glaze, and it is easy to change the length. In the separation membrane structure 20 of the present embodiment, the length of the first outer peripheral surface seal layer 291 is increased without changing the separation performance of the separation membrane 24 and the base material 22 itself. Since the separation amount is substantially uniform over the entire longitudinal direction, manufacture is easy and accuracy is not required as compared with the other methods described above. Moreover, it is also possible to finely adjust the separation performance of the separation membrane structure 20 by adjusting the length of the first outer peripheral surface seal layer 291.

B. Modification:
The present invention is not limited to the above-described embodiment, and can be realized in various configurations without departing from the scope of the invention. For example, the technical features in the embodiments corresponding to the technical features in the respective forms described in the section of the summary of the invention can be used to solve some or all of the problems described above, or one of the effects described above. Replacements and combinations can be made as appropriate to achieve part or all. Also, if the technical features are not described as essential in the present specification, they can be deleted as appropriate. For example, the following modifications are also possible.

B-1. First modification:
The shape of the outer peripheral surface sealing layer 29 is not limited to the above embodiment. The outer peripheral surface sealing layer 29 reduces the pressure difference across the separation membrane 24 at least on the upstream side (at least a part of the first structure end face 28F and the bisector CL) in the flow direction of the liquid to be treated. It may be configured to Furthermore, the outer peripheral surface sealing layer 29 is more preferably formed so that the transmembrane pressure difference of the separation membrane 24 is substantially constant over the entire longitudinal direction. For example, a modification as shown in FIG. 6 is also possible.

  FIG. 6 is a schematic view schematically showing the appearance of the separation membrane structure of the modification. The outer peripheral surface seal layers 29A to 29E shown in FIGS. 6A to 6E are formed to reduce at least the transmembrane differential pressure of the separation membrane 24 on the upstream side in the flow direction of the liquid to be treated. Although the outer circumferential sealing layers 29A to 29E have different shapes, the area on the first end face 221 side is the area on the second end face 222 side with the bisector CL in the longitudinal direction of the base material 22 as a boundary. large.

  As shown in FIG. 6 (A), in the separation membrane structure 20A of the modification 1, the outer peripheral surface seal layer 29A is the same as the above embodiment, with the first outer peripheral surface seal layer 291A and the second outer peripheral surface seal. And a layer 292A. The longitudinal length of the first outer peripheral seal layer 291A is shorter than half the length of the base 22, but is longer than the second outer peripheral seal layer 292A. As shown in FIG. 6B, in the separation membrane structure 20B of Modification 2, the outer peripheral surface seal layer 29B has a first outer peripheral surface seal layer 291B, a second outer peripheral surface seal layer 292B, and a third outer periphery. And a face seal layer 293B. That is, the outer peripheral surface sealing layer 29B of the second modification is divided into three regions. As shown in FIG. 6C, in the separation membrane structure 20C of Modification 3, the outer peripheral surface seal layer 29C has a first outer peripheral surface seal layer 291C, a second outer peripheral surface seal layer 292C, and a third outer periphery. A face seal layer 293C and a fourth outer circumferential seal layer 294C are provided. That is, the outer peripheral surface sealing layer 29C of the third modification is divided into four regions. Then, two regions (a first outer peripheral surface seal layer 291C and a third outer peripheral surface seal layer 293C) are formed on the first end face 221 side with a bisector CL in the longitudinal direction of the base material 22 as a boundary. Two regions (a second outer peripheral seal layer 292C and a fourth outer peripheral seal layer 294C) are also formed on the second end surface 222 side. As shown in FIG. 6D, in the separation membrane structure 20D of Modification 4, the first outer peripheral surface seal layer 291D includes a first outer peripheral surface seal layer 291D and a second outer peripheral surface seal layer 292D. , (Here, five) third outer peripheral seal layers 293D (provided with three third outer peripheral seal layers 293D on the rear surface of FIG. 6 (D)). The third outer peripheral seal layer 293D is extended in a strip shape in the longitudinal direction from the first outer peripheral seal layer 291D. That is, the outer peripheral surface seal layer 29D of the fourth modification is divided into two regions (a region of 291D + 293D and a region of 292D). As shown in FIG. 6E, in the separation membrane structure 20E, the outer peripheral surface sealing layer 29E includes a plurality of (first four outer peripheral surface sealing layer 291E, second outer peripheral surface sealing layer 292E, and here) And the third outer peripheral seal layer 293E) (with two third outer peripheral seal layers 293E on the rear surface of FIG. 6 (E)). The third outer peripheral surface seal layer 293E is formed in a band shape connecting the first outer peripheral surface seal layer 291E and the second outer peripheral surface seal layer 292E, and forms one region as a whole. The third outer peripheral surface seal layer 293E has a width (length in the circumferential direction of the base material 22) becoming smaller from the first structure end face 28F side to the second structure end face 28S side. As shown in FIG. 6F, in the separation membrane structure 20F of the sixth modification, the outer circumferential surface sealing layer 29F is provided with a plurality of circular holes 298 and is formed on the entire outer circumferential surface 223 of the base material 22. The plurality of circular holes 298 are formed such that the radius gradually increases from the first end face 221 of the base material 22 to the second end face 222.

  As described above, the outer peripheral surface sealing layers 29A to 29E shown in FIGS. 6A to 6E are the first end face 221 side (upstream side) with the bisector CL in the longitudinal direction of the base material 22 as a boundary. Is larger than the area of the second end face 222 side (downstream side), the membrane blockage of the separation membrane 24 in the vicinity of the inlets (first end face) of the separation membrane structures 20A to 20F as in the above embodiment. Can be suppressed.

B-2. Second modification:
Although glass is illustrated as a material which forms end face seal layer 28 and peripheral face seal layer 29 in the above-mentioned embodiment, it is not limited to this. For example, tetrafluoroethylene such as PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), ETFE (tetrafluoroethylene-ethylene copolymer), etc. as a basic molecule You may use fluorine resin, such as copolymer fluorine resin compound and framed tetrafluoroethylene simple substance. A copolymerized fluorocarbon resin compound having a basic molecular skeleton of tetrafluoroethylene has a relatively low melt viscosity and good fluidity at the time of melting, and therefore it is possible to form a thick seal layer without causing a crack, It is suitable when forming a seal layer in the surface where surface roughness is large. Moreover, you may form by the material which has rubber elasticity, such as a fluorine-type elastomer.

B-3. Third modification:
In the above embodiment, as the shape of the base material 22, the cylindrical shape in which the flow path 26 having a circular cross-sectional shape (the cut surface perpendicular to the axis of the base material 22) is formed is illustrated. It is not limited to. For example, the shape of the first and second end faces may be a cylindrical shape forming an ellipse. The shapes of the first and second end faces may be polygonal prisms (triangular, tetragonal, pentagonal, hexagonal, etc.). Furthermore, it may be plate-like. In addition, the cross-sectional shape of the flow path may be an elliptical shape or a polygonal shape (a triangle, a quadrangle, a pentagon, a hexagon, or the like). Moreover, in the said embodiment, although the example provided with several flow path was shown, the number of flow paths is not limited to the said embodiment, You may be more or less than the said embodiment. For example, the number of flow paths may be one. When the number of flow channels is one, the shape of the substrate can be formed into a tubular (cylindrical) shape.

B-4. Fourth modified example:
Although the example of the formation method of the outer peripheral surface sealing layer 29 was shown in the said embodiment, the formation method of the outer peripheral surface sealing layer 29 is not limited to the said embodiment. The drying temperature, the time, the method of applying the seal layer forming paint, and the like may be appropriately selected. For example, as a coating method, dip coating, spin coating, electrostatic coating method or the like may be used. The application of the paint forming the outer peripheral surface sealing layer 29 may be repeated multiple times. In the above embodiment, in the case of forming the first outer peripheral seal layer 291 by dip coating (immersion), it is preferable to form a mask on the separation film 24 to form the first outer peripheral seal layer 291. This is because the formation of a glass coating on the surface of the separation membrane 24 can be prevented.

B-5. Fifth modification:
In the above embodiment, although the porous body made of alumina is used as the base material 22 and the porous membrane made of alumina is used as the separation membrane 24, the materials of the base material and the separation membrane are not limited thereto. As the substrate, various porous inorganic materials can be used. For example, ceramics such as mullite, titania, zirconia and the like may be used, or metal materials such as stainless steel and titanium may be used. Solid-liquid separation membrane (microfiltration membrane (MF), nanofiltration membrane (NF), limited) consisting of mullite, titania, zirconia, zeolite, palladium, carbon, amorphous silica, MOF (metal organic structure) etc. as a separation membrane An ultrafiltration membrane (UF), a reverse osmosis filtration membrane (RO), or a separation membrane that can be separated at the molecular level may be used.

B-6. Sixth modification:
In the above embodiment, a multi-layered base having a plurality of layers with different pore sizes and materials in the region of the base where the separation membrane is formed may be used. For example, a two-layer structure in which an intermediate layer having a porous structure smaller in pore diameter than the base material 22 and larger than the separation membrane 24 is provided on the surface of the flow path 26 of a support having the same shape as the base material 22 of the above embodiment. The following base materials can be used. In this case, the separation membrane 24 may be formed on the surface of the intermediate layer. The intermediate layer may be formed of the same material as the support or may be formed of a different material. Also, the intermediate layer may be formed of the same pore size as the support and of a material different from that of the support. Furthermore, the intermediate layer may be two or more layers to form a substrate having three or more layers.

B-7. Seventh modified example:
In the above embodiment, an example is shown in which the first outer peripheral seal layer 291 is extended from the first end seal layer 281 and the second outer peripheral seal layer 292 is extended from the second end seal layer 282. However, the outer peripheral surface sealing layer 29 may be formed independently of the end surface sealing layer 28. For example, the cylindrical first outer peripheral seal layer 291 and the second outer peripheral seal layer 292 may be prepared and fitted on the outer peripheral surface 223 of the base material 22. Also, for example, in the case of the outer peripheral seal layer 29B having the configuration as shown in FIG. 6B of the first modification, the first outer peripheral seal layer 291B is extended from the first end seal layer 281 ( The second outer peripheral seal layer 292 is formed integrally with the first end face seal layer 281 and extended from the second end face seal layer 282 (formed integrally with the second end face seal layer 282) The third outer peripheral seal layer 293 B formed in a cylindrical shape in advance may be fitted on the outer peripheral surface 223 of the base material 22. As described above, when the outer peripheral surface seal layer 29 is formed independently of the end surface seal layer 28, for example, a heat-shrinkable tube can be used as the outer peripheral surface seal layer 29. When using a heat-shrinkable tube, prepare a heat-shrinkable tube with an inner diameter larger than the outer diameter of the substrate 22, insert the substrate 22 into the heat-shrinkable tube, and heat and shrink the heat-shrinkable tube, The outer peripheral seal layer 29 can be formed.

20, 20A to 20F, 20P: separation membrane structure 22: base material 24: separation membrane 26: flow path 28: end face seal layer 29, 29A to 29F: outer peripheral surface seal layer 30: housing 31: introduction port 32: concentration Liquid discharge port 33: first filtrate port 34: second filtrate port 35: metal blocking member 36: metal blocking member 37, 38, 39 O-ring 100: separation membrane structure module 221: first End face 222 Second end face 223 Outer peripheral surface 281 First end face seal layer 282 Second end face seal layer 291 291A to 291E, 291P First outer peripheral face seal layer 292 292A to 292E, 292P Second outer peripheral seal layer 293B to 293E third outer peripheral seal layer 294C fourth outer peripheral seal layer 298 circular hole CL bisecting line

Claims (5)

A base material made of a porous inorganic material comprising a first end face in the longitudinal direction, a second end face, an outer peripheral surface, and a flow path communicating the first end face and the second end face;
A separation membrane formed on the inner wall surface of the flow path,
An outer peripheral surface sealing layer formed on at least a part of the outer peripheral surface of the base material;
Equipped with
The first end face is an inlet side into which the fluid to be treated flows,
The outer peripheral surface sealing layer is a separation membrane structure in which the area of the first end face side is larger than the area of the second end face side with the bisector of the length in the longitudinal direction of the base material as a boundary. . In the separation membrane structure according to claim 1 ,
It further comprises a first end face seal layer formed on the first end face of the substrate and a second end face seal layer formed on the second end face,
The separation membrane structure, wherein the outer peripheral surface sealing layer is extended from at least one of the first end surface sealing layer and the second end surface sealing layer. In the separation membrane structure according to claim 1 or 2 ,
The separation membrane structure, wherein the outer peripheral surface sealing layer is divided into two or more regions. A separation membrane structure module, comprising: the separation membrane structure according to any one of claims 1 to 3 ; and a case for storing the separation membrane structure inside. In the separation membrane structure module according to claim 4 ,
The separation membrane structure module, wherein the separation membrane structure is stored in the housing through a seal member made of an elastic material.

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