KR20050025154A - Spiral membrane element, reverse osmosis membrane module, and reverse osmosis membrane device - Google Patents

Abstract

A spiral membrane element, comprising a bag-like separating membrane wound, together with a raw water spacer, on the outer peripheral surface of a permeated water collecting tube, the raw water spacer further comprising first wire materials and second wire materials extending from the inflow side to the outflow side of raw water in a gently meandering curved shape, wherein the first wire materials extend along one membrane face of the separating membrane and form one raw water passages between the adjacent first wire materials, and the second wire materials extend along the other membrane face of the separating membrane and form the other raw water passages between the adjacent second wire materials, and the first and second wire materials are partly overlapped with each other and joined to each other at the overlapped positions.

Description

Spiral membrane element, reverse osmosis membrane module and reverse osmosis membrane device {SPIRAL MEMBRANE ELEMENT, REVERSE OSMOSIS MEMBRANE MODULE, AND REVERSE OSMOSIS MEMBRANE DEVICE}

The present invention relates to a spiral membrane element, a reverse osmosis membrane module and a reverse osmosis membrane device capable of stable water flow treatment for a long time without pretreatment, even in raw water having high turbidity such as industrial water.

Conventionally, as a method of obtaining desalination of seawater, ultrapure water, and various manufacturing process waters, ionic components are contained in raw water using a spiral membrane element having a reverse osmosis membrane (RO membrane) or a nano filtration membrane (NF membrane) as a permeable membrane. However, a method for separating low molecular weight components is known. As illustrated in FIG. 9, the spiral membrane element generally used in the related art forms an encapsulated membrane 93 by laminating a reverse osmosis membrane 91 on both sides of the permeate spacer 92 and bonding three sides thereof. The opening of the encapsulated membrane 93 is attached to the permeate collection pipe 94 and wound together with the reticulated raw water spacer 95 on the outer circumferential surface of the permeate collection pipe 94 in a spiral shape. . The raw water 96 is supplied from one end surface side 9a of the spiral membrane element 90, flows along the raw water spacer 95, and the other end surface side of the spiral membrane element 90 ( 9b) is discharged as concentrated water 98. In the process of flowing along the raw water spacer 95, the raw water 96 is permeate | transmitted through the reverse osmosis membrane 91, and becomes permeate 97, This permeate 97 is permeate | water permeate | transmitted along the permeate spacer 92 It flows into the collection pipe 94 and is discharged from an end of the permeate collection pipe 94. In this way, the raw water path is formed by the raw water spacer 95 disposed between the wound encapsulation film 93.

When desalination of seawater, ultrapure water, and various manufacturing process waters are obtained using such a spiral membrane element, pretreatment is usually performed for the purpose of removing turbidity of raw water. The reason for this pretreatment is that the thickness of the raw water spacer of the helical membrane element is generally as thin as 1 mm or less since the contact area between the raw water and the reverse osmosis membrane is as large as possible while securing the raw water flow path, and the turbidity is the raw water flow path. Accumulated in the raw water spacers in the structure, it is easy to block the raw water flow path, so that the turbidity in the raw water is removed in advance, thereby avoiding the increase in the water flow differential pressure due to the turbidity accumulation, or the decrease in the permeated water quality and the permeated water quality. This is to perform stable operation. The pretreatment apparatus used for the purpose of removing the turbidity includes, for example, respective apparatuses such as flocculation sedimentation treatment, filtration treatment, and membrane treatment, and these installations increase installation costs and operating costs, and also provide a large installation area. There was a problem such as need. For this reason, when the raw water flow path can be secured by the thin raw water spacer like the conventional example, the desalination rate equivalent to the conventional one can be maintained, and the spiral membrane element of the structure which does not accumulate turbidity is developed, industrial water B Tap water can be supplied without pretreatment, which simplifies the system, reduces the installation area, and lowers the cost, resulting in extremely high industrial value.

On the other hand, in order to prevent the blockage of the raw water flow path by turbidity of a spiral membrane element, various proposals which improved the structure of the raw water spacer on the grid of the conventional grid | lattice are made | formed. Japanese Laid-Open Patent Publication No. 64-47404 discloses a spiral membrane element using raw water spacers having a shape in which the waveform meanders in a corrugated plate. This meandering wave shape raw water spacer is difficult to be molded, and when wound in a spiral shape, the flow path is likely to be damaged, which is not practical.

Japanese Patent Laid-Open No. 9-299770 discloses that the first wire material and the second wire material are formed in a lattice shape so as to cross each other, and the first wire material or the second wire material is formed in the longitudinal direction of the permeate collection pipe. Disclosed is a structure in which raw water spacers are arranged to be parallel. According to the raw water spacer of this structure, since the raw water flows in a substantially linear shape in a direction parallel to the longitudinal direction of the permeate collection pipe, the pressure loss is low, the linear velocity of the raw water is increased, and the turbidity in the raw water becomes difficult to accumulate. On the other hand, since the wire material existing in the direction perpendicular to the longitudinal direction of the collecting pipe blocks the flow path of raw water, turbidity accumulates in this wire material, which also causes the blockage of the raw water flow path.

In Japanese Patent Laid-Open No. 10-156152, as shown in FIG. 8, a wire material is present in a zigzag shape extending from the inflow side X of the raw water toward the outflow side Y, and the wire material is face to face. The first wire material 81 extends along the membrane surface of one of the separation membranes 80 and the second wire material 82 extends along the membrane surface of the other separation membrane. Between the neighboring first wire materials and the neighboring second wire materials, raw water flow paths which extend continuously along the membrane surface of the separator from the inflow side to the outflow side of the raw water are formed, respectively. Part of the first wire material and the second wire material (81b, 82a) is overlapped, and the raw water spacer of the structure which couples in this overlapping position is disclosed. According to the raw water spacer of this structure, the blockage of the raw water flow path by turbidity is suppressed compared with the conventional raw water spacer of the grating | lattice, but in the vicinity of the corner part C of the 1st wire material 81 in FIG. The stagnation of raw water cannot be solved even if it is influenced by the flow of the high velocity in the protrusion B of the second wire material 82, for example. For this reason, accumulation of turbidity also occurs in long-term use.

As described above, any of the network spacers composed of the first wire material and the second wire material among the raw water spacers proposed in the related art has a portion that becomes a corner portion or a bending point in the raw water flow path, and this is the stagnation of raw water. In the long-term use, the accumulation of turbidity occurs, and the increase in the pressure difference of the water cannot be avoided, and the current state is not reached until the pretreatment of the raw water, which has been conventionally performed, is omitted. From the viewpoint of forming the flow path without bending point while securing the raw water flow path, it is most preferable to have a structure formed only of the wire material extending linearly or approximately linearly from the inflow side of the raw water toward the outflow side. Since it is not a structure to connect, it is difficult to manufacture industrially.

Accordingly, an object of the present invention is to provide a spiral membrane element, a reverse osmosis membrane module, and a reverse osmosis membrane device which are difficult to accumulate turbidity and provide stable water permeation treatment for a long time even when raw water such as industrial water with high turbidity is supplied without pretreatment. It is to offer.

FIG. 1 is a diagram showing a raw water spacer in the embodiment.

FIG. 2 (a) is a view along the line A-A of FIG. 1, and FIG. 2 (b) is a view along the line B-B of FIG.

3 is an enlarged perspective view of a part of FIG. 1.

Fig. 4A is a diagram showing a first wire material constituting the raw water spacer, and Fig. 4B is a diagram showing a second wire material constituting the raw water spacer.

FIG. 5 is a diagram illustrating a raw water spacer in another embodiment. FIG.

FIG. 6 is a diagram showing an example of the structure of the reverse osmosis membrane module in the embodiment.

It is a figure which shows an example of the reverse osmosis membrane apparatus in embodiment of this invention.

8 is a view for explaining a conventional zigzag raw water spacer.

9 is a schematic diagram of a conventional reverse osmosis membrane module.

In this situation, the present inventors earnestly examined and, as a result, in the spiral membrane element formed by winding an encapsulated separation membrane together with the raw water spacer on the outer circumferential surface of the permeate collection pipe, the turbidity in the raw water is mainly accumulated in the raw water spacer. Intersections or bends where the wire materials intersect, thus straightening the flow of raw water without intersecting the wire materials and not forming a bend point, thereby greatly suppressing the accumulation of turbidity in the raw water spacers The present invention was found to complete the present invention.

In other words, the present invention (1) is a spiral membrane element formed by winding an encapsulated separation membrane together with raw water spacers on the outer circumferential surface of the permeate collection pipe, and the raw water spacers are gentle from the inflow side of the raw water toward the outflow side. It consists of the 1st wire material and the 2nd wire material which exist in the shape meandering in a curve, and this 1st wire material extends along the opposing membrane surface of this separation membrane, and is adjacent to the 1st wire material. One raw material flow path is formed between the wire materials, and the second wire material extends along the opposite membrane surface of the separation membrane, and between the second wire materials adjacent to each other. A raw water flow path is formed, and a part of this 1st wire material and this 2nd wire material overlaps, and it provides the spiral membrane element formed by combining in this overlapping location. By adopting such a configuration, the raw water flows from the inflow side to the outflow side along the membrane surface smoothly meandering or in a substantially straight line along the membrane surface. For this reason, accumulation of turbidity in a raw water flow path is largely suppressed.

Moreover, this invention (2) is a shape which meanders by the said gentle curve which has regularity without a bending point, and ratio (H / L) of amplitude (H) and wavelength (L) is 0.02-2, In addition, the spiral membrane element is characterized by having a wavelength of 1 to 100 per 1m per wire material. By taking such a configuration, it is possible to select and produce a suitable suitable numerical value suitable for the use or the use conditions, and the effect of the above invention can be reliably obtained.

Moreover, this invention (3) provides the reverse osmosis membrane module characterized by including the said spiral membrane element. By having such a structure, it is easy to carry in in a water treatment facility other than exhibiting the effect similar to the said invention, and can be attached to a process line in the form as it is.

This invention (4) provides the reverse osmosis membrane apparatus characterized by including the said reverse osmosis membrane module. When desalination of seawater, ultrapure water, and various manufacturing process waters are obtained using the reverse osmosis membrane device of the present invention, raw water with high turbidity, such as industrial water and tap water, can be supplied without pretreatment, thereby simplifying the system and reducing the installation area. It is possible to reduce the cost, and the industrial use value is extremely high.

In the present invention, the raw water spacer is composed of a plurality of first wire materials and a plurality of second wire materials which extend in a shape that meanders in a gentle curve from the inflow side of the raw water toward the outflow side. Although there is no restriction | limiting in particular as cross-sectional shape of a 1st wire material and a 2nd wire material, For example, a circle, a triangle, a square, etc. are mentioned. Moreover, the thing of the same dimension and the same cross-sectional shape is used for the 1st wire material and the 2nd wire material.

As a shape meandering by a gentle curve, the meandering shape which consists of a curved part except the inflection point and all have no bending point is illustrated, for example. A bending point means each part which consists of a straight line and a straight line, and has an angle. On the other hand, these parts include those whose angles are shaved or that each part has some roundness. Therefore, the so-called zigzag shape as shown in FIG. 8 is not included in the shape meandering with a gentle curve. Moreover, as a curved part, the semicircle shape always comprised by the same radius of curvature, the shape in which a radius of curvature changes continuously like the arc and sine curve of a part of a circle, etc. are mentioned. In the case of a semi-circle shape always composed of the same radius of curvature or an arc of a part of the circle, the radius of curvature of the curve is preferably 10 mm to 10,000 mm, preferably 20 mm to 5,000 mm. If the radius of curvature is less than 10 mm, stagnation is likely to occur in the flow of raw water, and in the long-term use, turbidity accumulates, and if it exceeds 10,000 mm, moldability deteriorates and production becomes difficult. Moreover, the shape meandering with a gentle curve is a regular shape which takes a repetitive form which has a wavelength and amplitude of a predetermined dimension, for example, but the irregularity which a wavelength or amplitude changes gradually in the longitudinal direction of a collection pipe or a direction perpendicular to it Although shape may be sufficient, a regular shape is preferable at the point which manufacture is easy.

The preferable form of the shape meandering with a gentle curve is demonstrated with reference to FIGS. Fig. 1 is a view showing a raw water spacer in this embodiment, Fig. 2 (a) is taken along the line AA of Fig. 1, Fig. 2 (b) is taken along the line BB of Fig. 1, Fig. 3. Is an enlarged perspective view showing a part of FIG. 1, FIG. 4 (a) shows a first wire material constituting a raw water spacer, and FIG. 4 (b) shows a second wire material constituting a raw water spacer. Drawing. In the figure, the shape of the raw water spacer 1 has regularity without a bending point, and the curved part is a gentle meandering shape in which the curvature radius changes continuously, and the wavelength L is 10-1,000 mm, Preferably it is 20-500 Mm and amplitude H are 2 to 200 mm, preferably 10 to 100 mm, and ratio H / L of amplitude H and wavelength L is 0.02 to 2, preferably 0.05 or more, 0.5 It is less than a range. In this case, it is 1-100 wavelength per meter of one wire material. If the ratio (H / L), amplitude (H), and wavelength (L) of the amplitude (H) and the wavelength (L) are within the numerical range, the raw water gently incurs in the raw water flow path or is in a substantially straight shape on the inflow side. It flows from the side toward the outflow side, and the accumulation of turbidity in the raw water flow path is prevented, and the raw water spacer can be manufactured.

The raw water spacer 1 in the present embodiment extends from the inflow side X of the raw water toward the outflow side Y in a plurality of first wire materials 11 and a plurality of second wire materials. As shown in FIG. 2, the first wire material 11 extends along the opposite membrane surface 21 in the separation membrane 20 and is adjacent to the first wire material. One raw water flow path 23 is formed from the inflow side X toward the outflow side Y in a shape that meanders in a gentle curve between (11, 11), and the raw water is the raw water flow path 23 of this one. ) Flows along the flow path formed on the film surface of the film 21. The second wire material 12 extends along the opposite membrane surface 22 of the separation membrane 20, and meanders in a gentle curve between adjacent second wire materials 12 and 12. The other raw water flow path 24 is formed from the inflow side X toward the outflow side Y, and the raw water also follows the flow path formed on the membrane surface of the membrane 22 with the other raw water flow path 24. Flow. And since the flow in the raw water flow path formed by this one raw water flow path 23 and the other raw water flow path 24 does not exist in the flow path direction, since there exists no bending point or a corner part, The flow is straight or close to straight. 3 and 4, reference numeral 231 denotes the flow of one raw water flow path, and reference numeral 241 denotes the flow of the other raw water flow path.

1 and 3, one of the protrusions 11a, 11a... In the gentle curve of the first wire material 11 is a gentle curve of the second wire material 12. It overlaps with the other protrusion part 12a, 12a ... in and is joined in this overlapping location. In addition, the other protrusions 11b and 11b ... in the gentle curve of the first wire material 11 are the one protrusions 12b and 12b in the gentle curve of the second wire material 12. ), And are joined at this overlapping position. Therefore, as shown in FIG. 4, the distance between the adjacent first wire materials 11 and 11 and the distance between the adjacent second wire materials 12 and 12, that is, the flow path width V In the form of FIG. 1, it is equal to twice the amplitude (H). For this reason, when the amplitude H is determined, the flow path width V is determined.

Another preferred form of the shape meandering with a gentle curve will be described with reference to FIG. 5. 5 is a diagram illustrating a raw water spacer in another embodiment. In FIG. 5, the point different from the raw spacer of FIG. 1 is mainly demonstrated. In other words, in FIG. 5, the difference from FIG. 1 is that the distance between adjacent first wire materials 51 and 51, and the distance between adjacent second wire materials 52 and 52, that is, the flow path width. (V) is at the same point as amplitude (H). In the first wire material 51 and the second wire material 52, the lower protrusions 51a and 52a and the upper protrusions 51b and 52b in a gentle curve are formed in FIG. And the intermediate part of the protrusion part 51a, 51b in the gentle curve of the 1st wire material 51, and the intermediate part of the protrusion part 52a, 52b in the gentle curve of the 2nd wire material 52 is carried out. This is overlapping and overlapping. Moreover, the protrusion part 51a of the lower side of the 1st wire material 51, and the protrusion part 52b of the upper side of the 2nd wire material 52 overlap. Moreover, the protrusion part 51b of the upper side of the 1st wire material and the protrusion part 52a of the lower side of the 2nd wire material 52 overlap. These overlapping portions are joined to each other, whereby an integral raw water spacer 1a is formed. Also in the spiral membrane element using the raw water spacer 1a, the flow path width V is half the width of that shown in Fig. 1, but similarly, a gentle curve between adjacent first wire materials 51 and 51 is obtained. One raw water flow path is formed from the inflow side X toward the outflow side Y in a meandering shape, and meanders in a gentle curve between adjacent second wire materials 52 and 52. The other raw water flow path is formed toward the outflow side Y from (X). And the flow in the raw water flow path formed by this one raw water flow path and the other raw water flow path tends to meander compared with the raw water spacer 1 of FIG. 1, but the grade which reaches the accumulation of turbidity no.

The thickness of the raw water spacer is the sum of the diameter of the first wire material and the diameter of the second wire material, or slightly thinner than that, and is in the range of 0.4 to 3.0 mm. When the thickness is less than 0.4 mm, the flow-through pressure rises, and turbidity accumulates easily. On the other hand, when thickness exceeds 3.0 mm, when it is set as a spiral shape, the film area per element will become too small and it is not practical. In addition, the flow path width V in the raw water spacer is not particularly limited, but in the case of the form of FIG. 1, it is twice the size of the amplitude H, and in the case of the form of FIG. Same dimension as Although it does not restrict | limit especially as a raw material spacer, Polypropylene and polyethylene are preferable at the point of moldability and cost. Moreover, the manufacturing method of a raw water spacer is not specifically limited, Although a well-known method is applicable, the molded article by a metal mold | die is preferable also from a cost point and a precision point.

The spiral membrane element of the present invention is formed by winding an encapsulated separator on the outer circumferential surface of the permeate collection pipe together with the raw water spacer. The winding may be a winding of one sealing membrane, or may be any of winding a plurality of sealing separators. The spiral membrane element of this invention can be used for membrane separation apparatuses, such as a microfiltration apparatus, an ultrafiltration apparatus, and a reverse osmosis membrane separation apparatus. Examples of the reverse osmosis membrane include conventional reverse osmosis membranes having a high removal rate of 90% or more with respect to sodium chloride in saline, nanofiltration membranes having a low desalination rate, and loose reverse osmosis membranes. Although nanofiltration membranes and loose reverse osmosis membranes have desalting performance, they have lower desalting performance than ordinary reverse osmosis membranes, and in particular, have separation performance of hardness components such as Ca and Mg. On the other hand, a nano filtration membrane and a loose reverse osmosis membrane may be called an NF membrane.

The reverse osmosis membrane module of the present invention is not particularly limited as long as the reverse osmosis membrane module includes the helical membrane element, and examples thereof include a reverse osmosis membrane module having a structure shown in FIG. 6. As shown in FIG. 6, a bag-shaped reverse osmosis membrane 61 is wound around the outer circumferential surface of the permeate water collecting tube 60 in a spiral shape together with the raw water spacer, and the upper portion thereof is covered with an outer body 62. In order to prevent the reverse osmosis membrane 61 wound around the spiral, the telescope fixing portion 64 having several radial ribs 63 is mounted at both ends. One spiral membrane element 65 is formed from these permeate collection pipes 60, reverse osmosis membrane 61, exterior body 62, and telescope fixing section 64, and each permeate collection pipe ( 60 is connected to a connector (not shown) to load a plurality of spiral membrane elements 65 into the housing 66. On the other hand, a gap 67 is formed between the outer circumference of the spiral membrane element 65 and the inner circumference of the housing 66, but the gap 67 is closed by the brine seal 68. On the other hand, one end of the housing 66 is a raw water inlet pipe (not shown) for introducing raw water into the housing, and the other end is a treated water pipe (not shown) and a non-permeable water pipe (not shown) in communication with the permeate collection pipe 60. And the reverse osmosis membrane module 69 is constituted by the housing 66, its internal parts, piping (nozzle), and the like.

When raw water is treated with the reverse osmosis membrane module 69 having such a structure, raw water is pressurized using a pump from one end of the housing 66. However, as shown by the arrow in FIG. 6, the raw water is a telescope fixing part. Passes between each radial rib 63 of 64 to break into the original spiral membrane element 65, and some raw water passes through the raw water flow path partitioned by raw water spacers between the membranes of the spiral membrane element 65. It passes and reaches the next spiral membrane element 65, and the other raw water penetrates the reverse osmosis membrane 61 and becomes permeate water, and this permeate water is collected by the permeate collection pipe 60. In this way, the raw water escapes the spiral membrane element 65 in succession, and the raw water which does not penetrate the reverse osmosis membrane is taken out from the other end of the housing 66 as concentrated water containing a high concentration of turbidity and ionic impurities. The permeate that has passed through the membrane is taken out of the housing 66 through the permeate collection pipe 60 as permeate water. On the other hand, the reverse osmosis membrane module of the present invention may be provided with one spiral membrane element, for example, in addition to the plurality of spiral membrane elements as shown in FIG. 6.

The reverse osmosis membrane device of the present invention is not particularly limited, but for example, one or two or more of the above reverse osmosis membrane modules, raw water supply means such as a pump, raw water inflow pipe, concentrated water outflow pipe, and permeate outflow pipe may be used. It is provided. Examples of the raw water directly supplied to the reverse osmosis membrane device of the present invention include industrial water, tap water and recovered water. Although turbidity of raw water is not restrict | limited, Even if it is a thing with high turbidity of about 2 degree of turbidity, it does not generate | occur | produce rise of the water flow differential pressure by occlusion of turbidity, etc. Moreover, when raw water contains coarse particles, such as sand particles, in raw water, the processed water which passed the filter which has coarse mesh in advance, and the thing which added the dispersing agent for preventing scale and fouling are included. By adding a dispersing agent, the accumulation of haze on the raw water spacer and the membrane surface can be further suppressed. As a dispersing agent, commercially available "hypersperse MSI300" and "hypersperse MDC200" (also, manufactured by ARGO SCIENTIFIC Corporation) are mentioned. According to the reverse osmosis membrane device of the present invention, it is possible to omit the installation of pretreatment devices such as flocculation sedimentation treatment, filtration treatment and membrane treatment, which have conventionally been used for the purpose of removing turbidity in raw water. For this reason, the effect is remarkable since the system is simplified, the installation area is reduced, and the cost is reduced.

An example of the reverse osmosis membrane apparatus in embodiment of this invention is demonstrated with reference to FIG. In FIG. 7, the reverse osmosis membrane apparatus 70 is a source water supply apparatus 71, a shear reverse osmosis membrane module 70A and a rear stage reverse osmosis membrane module 70B arranged in this order, and the raw water supply apparatus 71. ) And the shear reverse osmosis membrane module 70A are connected to the raw water supply pipe 72, and the shear reverse osmosis membrane module 70A and the rear stage reverse osmosis membrane module 70B are permeated water of the shear reverse osmosis membrane module 70A. Is supplied to the first permeate outflow pipe 73 for supplying the treated water of the rear end device, and the raw water is supplied to the rear end reverse osmosis membrane module 70B with the permeate outflow pipe 74 for discharging the permeate and the concentrated water. The return pipe 75 which returns to the pipe 72 is provided. In addition, the shear reverse osmosis membrane module 70A is provided with a concentrated water outlet pipe 76. The front reverse osmosis membrane module 70A is a reverse osmosis membrane device which does not cause the accumulation of turbidity according to the present invention, and the rear stage reverse osmosis membrane module 70B is a conventional reverse osmosis membrane device.

Next, a method of treating raw water using the reverse osmosis membrane device 70 of the embodiment will be described. First, raw water is supplied to the shear reverse osmosis membrane module 70A by the raw water supply means 71. The raw water is treated with the shear reverse osmosis membrane module 70A, and the primary concentrated water is obtained from the concentrated water outlet pipe 76 and the primary permeate is obtained from the primary permeate outlet pipe 73. Subsequently, this primary permeate is treated with a rear-end reverse osmosis membrane module 70B to obtain secondary permeate from the permeate outlet pipe 74, and the secondary concentrated water is supplied from the return pipe 75. The pipe 72 is returned. This secondary concentrated water is a concentration of the permeated water already desalted by the shear reverse osmosis membrane module 70A into the rear reverse osmosis membrane module 70B, and has a lower conductivity than that of the raw water. For this reason, it becomes possible to circulate the whole quantity of secondary concentrated water, and can improve a water recovery rate. In addition, the reverse osmosis membrane device 70 uses a reverse osmosis membrane module capable of significantly suppressing the accumulation of the turbidity in the present invention, instead of a pretreatment device for the purpose of only removing the turbidity used in the conventional apparatus. As a result, substantially two reverse osmosis membranes are used. Since the pretreatment apparatus in the conventional apparatus does not have a desalting function, the reverse osmosis membrane apparatus 70 is also superior in the quality of the permeated water as compared with the conventional reverse osmosis membrane apparatus.

Example 1

Industrial water having a turbidity of 2 degrees and a conductivity of 20 mS / m was passed through the reverse osmosis membrane module A having the following specifications, and the endurance operation was performed for 2,000 hours under the following operating conditions. The performance evaluation of the reverse osmosis membrane module A was performed by measuring the water passage differential pressure (MPa), the water permeation rate (l / min), and the electrical conductivity (mS / m) of the permeate water at the initial stage of operation and 2,000 hours. In addition, after 2,000 hours, the reverse osmosis membrane module was dismantled, and the adhesion state of the turbidity in the raw water flow path was observed. Table 1 shows the results of the measured values and visual observation results of the raw water flow paths. In Table 1, a water flow differential pressure and a permeate conductivity are 25 degreeC conversion value.

(Reverse osmosis membrane module A)

1 and 2, the amplitude (H) / wavelength (L) is 0.66, the wavelength (L) is 15 mm, the amplitude (H) is 10 mm, the raw water flow path width (V) is 20 mm, The raw water spacer A of thickness 1.0mm was produced. Subsequently, the spiral membrane element A was produced using this raw water spacer A, and the reverse osmosis membrane module A of the structure as shown in FIG. 6 was further produced. However, this reverse osmosis membrane module A was made into one module which accommodated one spiral membrane element.

(Operation conditions)

The operating pressure is 0.75 MPa, the concentrated water flow rate is 2.7 m 3 / hour, the water temperature is 25 ° C., and flushing for 60 seconds once every 8 hours (developing the valve attached to the concentrated water outlet pipe, The raw water at a flow rate three times the raw water supply flow rate is rapidly supplied into the reverse osmosis membrane module, and the flushing drainage flows out from the concentrated water outlet pipe).

Example 2

Instead of the reverse osmosis membrane module A, 2,000 hours of endurance operation was performed under the same operation conditions as those in Example 1 except that the reverse osmosis membrane module B having the specifications shown below was used. The performance evaluation results of the reverse osmosis membrane module B are shown in Table 1 and Table 2.

(Reverse osmosis membrane module B)

Instead of the raw water spacer A, it has the structure shown in FIG. 5, and amplitude (H) / wavelength (L) is 0.66, wavelength (L) is 15 mm, amplitude (H) is 10 mm, and raw water flow path width (V). ) Was manufactured by the same method as the said reverse osmosis membrane module A except having used the raw water spacer (B) of 10 mm and thickness 1.0 mm.

Example 3

Industrial water having a turbidity of 2 degrees and a conductivity of 20 mS / m was passed through the reverse osmosis membrane apparatus of the flow shown in FIG. 7 described above with the following specification, and the endurance operation was performed for 2,000 hours under the following operating conditions. Table 1 and Table 2 show the results of the performance evaluation of the reverse osmosis membrane device. In addition, the result of Table 1 is a result of a backward reverse osmosis membrane apparatus.

(Reverse osmosis membrane device)

As the reverse reverse osmosis membrane module, the reverse osmosis membrane module B used in Example 2 was used, and as the rear reverse osmosis membrane module, one module equipped with one 8-inch element ES-10 (manufactured by Nito Electric) was used. did. The raw spacer used in this ES-10 is a mesh of a lattice.

(Operation conditions)

For both the reverse reverse osmosis membrane module and the reverse reverse osmosis membrane module, the operating pressure was 0.75 MPa, the concentrated water flow rate was 2.7 m 3 / hour, the water temperature was 25 ° C., and the shear reverse osmosis membrane module only once every 8 hours for 60 seconds. Flushing (operation similar to Example 1) is performed.

Example 4

Instead of the reverse osmosis membrane module A, the endurance operation was performed for 2,000 hours under the same operating conditions as in Example 1 except that the reverse osmosis membrane module C having the specifications shown below was used. The performance evaluation results of the reverse osmosis membrane module C are shown in Table 1 and Table 2.

(Reverse osmosis membrane module C)

Instead of the raw water spacer A, it has the structure shown in FIG. 1, and the amplitude (H) / wavelength (L) is 0.2, the wavelength (L) is 100 mm, the amplitude (H) is 20 mm, and the raw water flow path width (V). ) Was manufactured by the same method as the said reverse osmosis membrane module A except having used the raw water spacer (C) of 40 mm and 1.0 mm in thickness.

Comparative Example 1

A method similar to that in Example 1 except that a known pretreatment device consisting of a membrane treatment is disposed at the front end and an 8-inch element ES-10 (manufactured by Nito Electric Co., Ltd.) is used instead of the spiral membrane element (A). Done. In other words, industrial water having a turbidity of 2 degrees and a conductivity of 20 mS / m was treated with a pretreatment device, and the treated water was further treated with a conventional commercially available reverse osmosis membrane module. The results are shown in Table 1 and Table 2.

Comparative Example 2

It carried out by the method similar to Example 1 except having used the 8-inch element ES-10 (made by Nito Electric Co., Ltd.) instead of the spiral membrane element (A). In other words, industrial water having a turbidity of 2 degrees and a conductivity of 20 mS / m was directly treated with a conventional commercially available reverse osmosis membrane module without being treated with a pretreatment apparatus. The results are shown in Table 1 and Table 2. On the other hand, in this comparative example 2, since the water flow differential pressure rose extremely in about 800 hours, permeate was not obtained, operation was stopped at this point.

Comparative Example 3

Instead of the reverse osmosis membrane module A, the endurance operation was performed for 2,000 hours under the same operating conditions as in Example 1 except that the reverse osmosis membrane module D having the following specifications was used. The results are shown in Table 1. On the other hand, this reverse osmosis membrane module D was made into one module which accommodated one spiral membrane element.

(Reverse osmosis membrane module D)

Instead of the raw material spacer A, it is of the structure shown in FIG. 1 of Unexamined-Japanese-Patent No. 10-156152, ie, the structure shown in FIG. 8 mentioned above, 1.0 mm in thickness and the angle (e) of a bending point part. ) Was produced by the same method as the reverse osmosis membrane module A except that the raw water spacer (E) having a distance of 60 degrees and a bending point of 5 mm was used.

Table 1

Table 2

In Examples 1 to 4, after 2,000 hours, there was little increase in the water flow differential pressure, no decrease in the amount of permeated water, and the quality of the water permeated was also high. Although the comparative example 1 showed the result similar to an Example in the performance evaluation after 2,000 hours, this has provided the pretreatment apparatus, and installation place, installation cost, etc. are needed more than necessary. Therefore, the comparative objects of Examples 1 to 4 are Comparative Examples 2 and 3, but Comparative Example 2 has a high adhesion of turbidity from about 800 hours until the permeation amount becomes zero, and Comparative Example 3 is significantly large at the stage of 2,000 hours. It was estimated that a normal increase in water pressure difference and a decrease in the amount of permeate were found to be unusable in about 3,000 to 4,000 hours.

According to the spiral membrane element of the present invention, the raw water flows from the inflow side to the outflow side while gently meandering or substantially linearly along the membrane surface between the wire materials having a meandering shape in a gentle curve. For this reason, accumulation of turbidity in a raw water flow path is largely suppressed. According to the reverse osmosis membrane module and reverse osmosis membrane apparatus of this invention, the installation of the pretreatment apparatus used conventionally for the purpose of removing the turbidity in raw water can be skipped. For this reason, a remarkable effect is exhibited by the simplification of a system, reduction of installation area, and cost reduction. Further, even if raw water having high turbidity, such as industrial water, is supplied without pretreatment, turbidity is less likely to accumulate, and stable water passage treatment is possible for a long time.

Claims (4)

A spiral membrane element formed by winding a bag-shaped separation membrane together with raw water spacers on the outer circumferential surface of the permeate collection pipe, and the raw water spacers extend in a meandering shape with a gentle curve from the inflow side of the raw water to the outflow side. Comprising a first wire material and a second wire material present, the first wire material extends along the opposite membrane surface of the separation membrane and is located between the adjacent first wire materials. The second wire material extends along the opposite membrane surface of the separator and forms the other raw water path between the adjacent second wire materials. A part of a 1st wire material and this 2nd wire material overlaps, and is comprised by this overlapping location, The spiral membrane element characterized by the above-mentioned. The shape which meanders with the said gentle curve is a shape which has regularity without a bending point, and ratio (H / L) of amplitude H and wavelength L is 0.02-2, Spiral membrane element, characterized in that 1 to 100 wavelength per 1m wire material. A reverse osmosis membrane module comprising the helical membrane element according to claim 1. The reverse osmosis membrane device of Claim 3 provided with the reverse osmosis membrane module.