KR100826363B1 - Spiral wound separation membrane element - Google Patents

Abstract

The present invention relates to a spiral separator device which can be efficiently separated and operated while reducing pressure loss of the supply-side passage even when operated at a low operating pressure, and can have a substantially sufficient membrane area. The spiral separator element comprises at least one membrane leaf comprising a perforated center tube and a separator, a feed side passageway and a permeate side passageway wound spirally around the supply side, the element having a supply side therein. The passage and the permeate side passage are formed, the width of the membrane leaf wound spirally is 900 to 2,000 mm, the length is 500 to 1,500 mm, and the thickness of the supply side passageway material is 1.0 to 2.0 mm.

Description

Spiral separator element {SPIRAL WOUND SEPARATION MEMBRANE ELEMENT}             

1A is a front view as an example of a supply-side passage member in the spiral separation membrane element of the present invention.

1B is a side view as an example of the supply-side passage member in the spiral separation membrane element of the present invention.

2 is a graph showing the relationship between the flow rate and the pressure loss in the embodiment when the thickness of the supply side passageway material is changed.

[Description of Symbols for Main Parts of Drawing]

1: warp

2: weft

t: thickness of supply side passageway

L1: Warp Pitch

L2: Weft Pitch

D1: warp diameter

D2: weft diameter

The present invention relates to a spiral separator element comprising a perforated center tube and a separator, a supply side passage member and a permeate side passage member spirally wound around the perforated tube, wherein a supply side passage and a permeate side passage are formed therein. More specifically, the present invention relates to a spiral separator element containing a supply side passageway material having a thickness effective to achieve a lower pressure loss for the supply side passage than usual and to ensure a practical membrane area.

Spiral separator modules have been used for a wide range of applications such as desalination of brine or seawater, production of ultrapure water, and wastewater treatment. The spiral membrane module has a structure including a pressure vessel and one or more spiral membrane elements housed therein.

The spiral membrane element is formed between the two separation membranes with a permeate side passage member to form an envelope-shaped membrane leaf, attaches the opening of the membrane leaf around the collecting pipe, and the mesh feed side passage member interposed between the membrane leaves and It is made by spirally winding the collecting pipe together with the membrane leaf. The stock solution is fed to one of the ends of the device, and the stock solution flows through a feed side passage formed between each pair of separators interposed with a feed side passage member and then discharged as a concentrate at the other end. In addition, the raw liquid flowing along the supply-side passage member partially passes through the separation membrane, and as a result, the permeated liquid flows through the permeate-side passage member into the collecting pipe and is discharged therefrom.

The supply-side passage member not only forms a passage in which the raw liquid flows between the membranes, but also acts to cause turbulence in the supply-side passage to agitate the raw liquid present in the passage to reduce concentration polarization. For this reason, the device has a pressure difference (pressure loss) between both ends thereof, that is, between the feed liquid supply surface and the concentrated water discharge surface.

Techniques have been proposed for reducing the pressure loss in the supply side passages of the device, including disposing the supply side passage members so that the net thread is inclined or using supply side passage members having a thickness of 0.5 to 0.9 mm (eg For example, Japanese Patent Laid-Open No. 1999-235520).

However, in devices operated at low pressure, the pressure loss was not sufficiently reduced when the devices were arranged in series or used for separation of suspensions such as waste water or separation of viscous liquids.

In recent years, low pressure devices operated at low pressure have been mainly used, and the ratio of pressure loss to effective pressure has become larger. In addition, when two or more elements connected together are used, the pressure loss as a whole of the elements is further increased. Therefore, there is a need to reduce the pressure loss for each element. In addition, for use in suspensions or viscous solutions such as waste water, the pressure loss of the individual devices must be reduced.

For example, when two or more devices are connected together, the pressure loss in terms of efficiency and energy loss reduction is preferably up to 5% of the operating pressure. Assuming six devices are connected, the pressure loss per device should be less than 0.8%. Experiments have shown that conventional devices have much higher losses than target values.

On the other hand, using a feed side passageway with increased thickness reduces the volume of the membrane leaf packed into the device, thus limiting the membrane area.

It is therefore an object of the present invention to provide a helical membrane element which can be effectively separated and operated while reducing the pressure loss to the supply side passage even when the element is operated at low pressure and can have a substantially sufficient membrane area.

This object can be achieved by the present invention as follows.

The invention comprises a perforated center tube and at least one membrane leaf comprising a separator, a feed side passageway and a permeate side passageway wound spirally around the feed side passage and a permeate side passage formed therein. There is provided a spiral separation membrane element, wherein the spirally wound membrane leaf has a width of 900 to 2,000 mm, a length of 500 to 1,500 mm, and a supply side passage member having a thickness of 1.0 to 2.0 mm.

The results obtained in the examples disclosed later show that six low-pressure elements with membrane leaf widths of 900 to 2,000 mm and lengths of 500 to 1500 mm and which are adjusted to have a feed side passageway thickness of 1.0 to 2.0 mm are arranged in series to provide general separation. Even when operating under conditions, it is shown that the pressure loss does not exceed 5% of the operating pressure. In addition, when the supply side passageway had a thickness within this range, it was further confirmed that the area of the packed membrane was in a practically sufficient range.

Aspects of the invention are disclosed below with reference to the accompanying drawings. 1A and 1B show an example of the supply-side passage material in the spiral membrane element of the present invention, in which FIG. 1A is a front view and FIG. 1B is a side view.

The spiral separation membrane element of the present invention comprises a perforated center tube and one or more separators, one or more feed side passages and one or more permeate side passages, spirally wound around the one or more feed side passages and one or more permeate It has a structure having a side passage. Membrane elements of this kind are disclosed in Japanese Patent Laid-Open No. 1999-235520 and also Japanese Patent Laid-Open No. 2000-000437, Japanese Patent Laid-Open No. 2000-042378, Japanese Patent Laid-Open No. 2005-168869, and the like. For components other than the supply side passage member, any conventional separation membrane, permeate side passage member, center tube, or the like can be used.

For example, the device is obtained by producing an envelope-shaped membrane leaf through a permeate side passageway between two separation membranes, attaching such membrane leaf openings to the collecting pipe, and spirally winding the membrane leaf near the center tube. It may have a structure.

The spiral separator device of the present invention has a spirally wound membrane leaf having a width of 900 to 2,000 mm and a length of 500 to 1500 mm. The width of the membrane leaf means the membrane leaf length measured in the axial direction of the center tube, and the length of the membrane leaf corresponds to the wound length of the membrane leaf being wound. In view of forming a feed side passage having an appropriate range of lengths and reducing the influence of the passage length on the pressure loss to effectively pressurize the stock solution, a membrane leaf having a width within this range in a spiral separator element that can be operated at low pressure may be used. It is preferable to use.

The thickness t of the supply-side passage member of the present invention is 1.0 to 2.0 mm, preferably 1.2 to 1.6 mm. If the thickness t is smaller than 1.0 mm, efficient separation operation is difficult when the separator element is operated at low pressure. When the thickness t exceeds 2.0 mm, it is difficult to secure a substantially sufficient film area.

The thickness t of the supply-side passage member is determined by, for example, the warp diameter D1 and the weft diameter D2 of the supply-side passage member shown in FIG. 1, or a structure for coupling the warp yarns to the weft yarn. The example shown in FIG. 1 is a supply side passageway having a warp yarn 1 extending substantially parallel to the flow direction of the feed liquid and a weft yarn 2 thinner than the warp yarn 1, where the weft yarn 2 is an inclined angle ( (theta) is inclined toward the warp yarn 1. The supply side passageway of the present invention is not limited to having the structure shown in Fig. 1, and any conventional network structure, for example, a rhombus, ladder or lattice structure can be used.

The ratio of warp diameter / weft diameter (D1: D2) is preferably (1 or more): 1, in particular 2: 1 to 3: 1. By thus regulating the diameter D2 of the weft to this small value, the cross-sectional area of the supply side passage increases, and the effect of reducing the pressure loss can also be improved in this way. That is, in the conventional membrane element, the weft yarn 2 has the same diameter as the warp yarn 1, and the passage cross-sectional area for the passage member is small compared to the large thickness t of the passage member. By using the thinner weft 2 and the thicker warp 1 while maintaining the same passage material thickness t, the passage material can have a larger passage cross-sectional area.

Examples of materials for the feed side passageway include resins such as polypropylene, polyethylene, poly (ethylene terephthalate) (PET) or polyamides, natural polymers and rubber. Among these, resins are preferably used.

Warp 1 and weft 2 may be multifilament yarns or single filament yarns. However, this is desirable because a single filament yarn is unlikely to be an obstruction to the passageway. Warp 1 may be bonded to the weft by fusion bonding, adhesion, or the like, or the supply side passageway may be a fabric. However, in view of keeping the passage stable, a passage member in which the warp yarn 1 is coupled to the weft yarn 2 is preferable.

Further, the angle θ at which the weft yarn 2 is inclined with respect to the warp yarn 1 is preferably 30 to 70 °, more preferably 45 to 60 ° in that the flow resistance by the weft yarn 2 is reduced. to be. The warp yarns 1 and the weft yarns 2 are preferably arranged so as to be disposed on one side of the warp yarn 1 in which all the weft yarns 2 are arranged as shown in FIG. 1B. This structure has the effect of reducing the resistance of the supply side passageway material.

The spiral separation membrane device of the present invention can be used with any filtration technique, such as reverse osmosis filtration, ultrafiltration and microfiltration. However, this disclosed feed side passageway is particularly effective when the elements are arranged in series with other elements of the same kind and operated at low pressures (operating pressures of 1 MPa or less) or when used for separation of suspensions such as waste water or separation of viscous liquids. Indicates.

The construction and effects of the present invention will be described with reference to the following examples.

Example

Poly with warp diameter of 0.7 mm, warp diameter / weft diameter of 1.5: 1, thickness of 1.16 mm, warp pitch of 5.5 mm, warp pitch / weft pitch ratio of 1: 1, and warp / weft cross angle of 47 ° A feed side passageway composed of propylene nets was used to produce an 8 inch reverse osmosis membrane device. Water was flowed through the device to measure flow rate and pressure loss. The obtained result is shown in FIG.

Comparative Examples 1 and 2

An 8-inch reverse osmosis membrane device was manufactured in the same manner as in the Examples, except that the warp diameter and the weft diameter of the supply-side passage member used in the Examples were obtained, respectively, 0.71 mm (Comparative Example 1) and 0.85 mm, respectively. Only the point manufactured from the supply side passageway material having the thickness of (Comparative Example 2) is different. Water was flowed through these elements, respectively, to measure flow rate and pressure loss. The obtained result is shown in FIG. 2 with the result obtained in the Example.

As shown in FIG. 2, the device of the example had a lower pressure loss than the devices of Comparative Examples 1 and 2. The pressure loss of the device of Example was about one third of the pressure loss of Comparative Example 2. When the stock solution flow rate was 100 L / min, the pressure loss of the device of the example was about 0.004 MPa. Even in the case where six elements identical to those of the example were arranged in series, its pressure loss value was six times the pressure loss value, that is, 0.024 MPa. When these elements are operated at 1 MPa, this pressure loss is 2.3%.

In addition, the salt blocking rate of the element of the Example was 99.9% based on the value of the comparative examples 1 and 2. As shown in FIG. Therefore, the effect of reducing the concentration polarization by turbulence was confirmed. When a feed side passageway with a thickness of 2.0 mm was used in an 8 inch low pressure reverse osmosis membrane element, the membrane area was 18 m ² , which was found to be within the practical range.

According to the present invention there is provided a spiral membrane element which can be effectively separated and operated with a substantially sufficient membrane area while reducing pressure loss on the supply side passage even when operated at low pressure.

Claims (1)

A perforated center tube, and one or more membrane leaves, including a separator, a feed side passageway and a permeate passageway, wound spirally around the feed tube and a permeate side passage formed therein; As a spiral separator element, The membrane leaf wound in a spiral has a width of 900 to 2,000mm and a length of 500 to 1,500mm, the thickness of the supply-side passage member is 1.0 to 2.0mm, Wherein said supply side passageway comprises a warp and a weft inclined at an inclination angle of 30 to 70 ° with respect to the warp.

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