JPH04131435U - Rotary membrane separator - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the flow pressure drop caused by supplying and discharging the liquid to be treated in the rotary membrane separator. [Structure] A membrane element consisting of a large number of membrane leaves with separation membranes on both sides of a disc-shaped support is stacked around a hollow rotating shaft.
Through a flexible partition fixed to the container between the membrane leaves,
A flexible tube fixed to the container is provided with a supply channel and a discharge channel for supplying and discharging the liquid to be treated in parallel to each membrane leaf in parallel and symmetrical positions with the rotation axis. The membrane is housed so that the partition is interposed between the membrane leaves and rotated by external power. [Effect] By supplying and discharging the liquid to be treated in parallel,
Pressure loss is significantly reduced, and the effect is approximately proportional to the square of the number of membrane leaves.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a rotary membrane separation system with a flat rotating membrane leaf and a flat fixed partition. It is related to the device.

0002

[Conventional technology]

In membrane separation, performance degradation occurs when solutes and solids that do not pass through the membrane accumulate on the membrane surface. In order to reduce the Flow filtration method is widely used.

0003 In the cross-flow filtration method using a stationary membrane module, the liquid to be treated is pumped under pressure. Conventionally, methods have been put to practical use in which the membrane is fed at a desired flow rate along the membrane surface. The effect of flow rate on membrane performance is, for example, the main factor in the desalination of brine or seawater using reverse osmosis membranes. This is noticeable in the improvement of salt rejection rate. Also, fruit juice containing polymeric solutes and suspended solids , fermentation liquid, etc., or various waste liquids, etc., using ultrafiltration membranes or precision filtration membranes. This is noticeable in the improvement of permeation flux.

0004 In ultrafiltration and precision filtration methods, the resistance of the boundary layer is generally more important than the permeation resistance of the membrane itself. It is large, and cases of more than one digit are not rare. In this way, a large boundary resistance can be In order to reduce this by However, most of it is discharged from the membrane module without passing through the membrane, so it requires a huge amount of input. Most of the energy will be wasted.

[0005] One way to reduce this loss is to increase the amount of liquid to be treated discharged from the membrane module. part is circulated to the membrane module inlet without pressure relief through the back pressure regulating valve. A method has been adopted to reduce the energy lost due to flow pressure drop for this circulating fluid. Just replenish. However, even with this method, the pressure drop due to high flow rate is large, and a large amount of air In addition to requiring energy replenishment, the inlet pressure may exceed the pressure limit of the membrane module. If it becomes necessary to limit the flow length so that it does not exceed the This has the disadvantage that power costs and equipment costs increase due to the large size.

[0006] As a way to solve this problem, the liquid to be treated is made to flow at high speed against the stationary membrane surface. Instead, by moving the membrane surface or an object, wall surface, etc. facing the membrane surface, the membrane surface can be moved. Mainly proposed are methods in which the liquid to be treated is brought into a relatively cross-flow state.

[0007] For example, Japanese Patent Application Laid-Open No. 48-65179 shows a device and method using a flat membrane as shown in Fig. 3. As shown, a hollow rotating container 1 has a liquid inlet 2 and a concentrate outlet 3. Separation membranes are installed on both surfaces of a disk-shaped membrane support 7 that has a shaft 4 and a partition 5 and has a through hole in the center. The membrane leaf covered with 8 is connected so that the inside 9 of the membrane leaf and the hollow part 10 of the rotating shaft communicate with each other through the small hole 6. By attaching the membrane separation device to the membrane and rotating the membrane leaf through the rotating shaft , discloses a membrane separation method that generates a high velocity gradient on the membrane surface.

[0008] By interposing rotating partitions between stationary disk-shaped membrane leaves, the It is expected to prevent the decrease in velocity gradient due to synergistic circulation of liquid and increase the shear rate on the membrane surface. Ru. For example, in Japanese Patent Application Laid-open No. 49-74175, the center hole of the membrane leaf is sealed liquid-tightly, The membrane permeate is taken out of the container from the outer periphery of the membrane leaves, and passed through the membrane provided between the membrane leaves. The cutter is rotated by a rotating shaft that passes through the center hole of the membrane leaf in a non-contact manner to release the liquid to be treated. The present disclosure discloses an apparatus for causing a flow of water parallel to the membrane surface.

[0009]

[Problem that the idea aims to solve]

Conventional rotary membrane separators do not need to supply the liquid to be treated at a high flow rate, as mentioned above. However, as is clear from Figure 3, the liquid to be treated is distributed between all the membrane leaves. Flows in series, the flow path becomes long, and even if the supply flow rate is the same, the flow between each membrane leaf becomes parallel. The pressure loss is much larger than when the flow is in a column. Therefore, ensuring effective filtration pressure The disadvantage is that the supply pressure has to be high in order to have.

0010

[Means to solve the problem]

Minimize the flow pressure drop when the amount of inflow and outflow of the liquid to be processed into the membrane separator is given. The method is to distribute the liquid to be treated so that the flow paths between each membrane leaf and the partition are all parallel. It is to be.

[0011] That is, the present invention has separation membranes on both sides of a flat support having a membrane permeate flow path inside. The outer circumference is liquid-tightly sealed, and the membrane leaves are penetrated at regular intervals through a hollow rotating shaft. The permeate flow path of the membrane leaf and the hollow part of the hollow rotating shaft are connected through a small hole in the rotating shaft wall. The membrane element is rotatable inside the container and is sealed liquid-tightly from the outside. In a rotary membrane separator having a fixed plate-like partition between the membrane leaves, , a supply channel and a discharge channel configured to supply and discharge the liquid to be treated in parallel to each membrane leaf. The present invention relates to a rotary membrane separator characterized in that do. With this configuration, the liquid to be treated is supplied to the supply channel with a sufficient cross-sectional area. is transported to all membrane leaves with practically negligible low pressure drop and processed at each membrane leaf. The liquid passes through a discharge channel with a sufficient cross-sectional area with extremely low pressure loss that can be virtually ignored. and is discharged.

0012 Of the liquid to be treated that is supplied to each membrane leaf, it does not flow on the membrane surface, but rather Side currents that flow through the gap with the container cause energy loss and must be suppressed as much as possible. Ru. This requires minimizing the gap between the membrane leaf and the container; In this case, it is preferable that the membrane leaf is a perfect circle and that the cross section inside the container is also a perfect circle. In addition, providing the means to prevent the partitions from rotating inward from the inner wall of the container reduces the energy consumption mentioned above. This is not preferable from the point of view of energy loss. If the container itself is formed by stacking annular bodies, Although it is possible to sandwich it between annular bodies, the cost is high. make a container from a cylinder When using a flat membrane leaf, a groove is provided approximately parallel to the axis of rotation and outside the outer circumferential locus of the flat membrane leaf. A counter-circulation prevention means is provided in the treated liquid supply flow path and/or discharge flow path, and a flat partition is installed. A protrusion is provided in the portion corresponding to the supply flow path and/or discharge flow path, and this protrusion is between the membrane leaf and partition and the inner wall of the container by being anchored to the co-rotation prevention means. The gap can be minimized.

[0013] As the means for preventing the partitions provided in the supply flow path and/or the discharge flow path from rotating together, For example, a rod-shaped body is provided in the flow path parallel to the flow path, and the protrusion of the partition plate is fitted into the rod-shaped body. The purpose is achieved by providing a smooth hole around the rod and passing it through the rod-shaped body. be able to. Use spacers to adjust the distance between the partitions and the distance between the partition and the membrane leaf. It can be adjusted and held by passing it through.

[0014] The membrane leaf used in this invention is made of polyethylene, polypropylene, etc. polyolefins such as polyvinyl chloride, polymethyl methacrylate, Vinyl polymers such as listyrene, polyamides, polyimides, polyesters, polycarbonates plastics such as polycarbonates, polysulfones, polyethersulfones, etc. A flat plate-shaped molded body consisting of a molded body with a permeate flow path on the surface or inner layer, or A perforated sheet such as a screen mesh or non-woven fabric is layered onto a flat plate-shaped molded body made of materials such as Glue, plastic granules, metal granules, sintered plate, or screen mesh , resin-treated woven fabrics, bristle woven fabrics, and non-woven fabrics that are resistant to pressure and fluid flow. The membrane support is a flat plate with channels, and polyacrylon is coated on both surfaces of the membrane support. Ultrafiltration membranes such as tolyl, polysulfone, polyamide, polyolefin, etc. reverse osmosis membranes such as microfiltration membranes, cellulose acetate membranes, cross-linked polyamide membranes, etc. Layer other flat separation membranes with selective permeation function, and coat the outer periphery with polyurethane or epoxy. Examples include those sealed with an adhesive such as a cylindrical adhesive.

[0015] The membrane leaf prepared in this way is fitted onto a hollow rotating shaft, and its contact surface is elastic. Seal liquid-tight with an O-ring, spacer, adhesive, etc. On the other hand, the inside of the hollow rotating shaft and the supporting It communicates with the permeate flow path of the holder through a small hole provided in the wall of the rotating shaft. Also, books In the design, lightweight and flexible partitions are preferably used, but the materials used are For example, polyolefins such as polyethylene and polypropylene, polyvinyl Chloride, polyvinylidene chloride, polytetrafluoroethylene, polyvinylidene chloride Vinyl polymers such as nylidene fluoride, polyamides, polyimides, polyesters films or sheets of organic polymers such as cellulose esters, etc. These examples include, but are not limited to.

[0016] The partition in this invention is a concentric circle with a hole in its center that has a diameter larger than the outer diameter of the rotating shaft. The shape may have protrusions for engagement on the outer periphery, or it may not be limited to a circular shape. It may be a polygon in which the protrusions are connected by curves or straight lines.

[0017] A structure consisting of membrane leaves and a hollow rotating shaft usually has more than 100 membrane leaves laminated. A suitable and practical membrane element length is 1 to 3 m.

[0018]

【Example】

An embodiment of the invention is shown in FIGS. 1-2. The left half of Figure 2 (hatched area with vertical lines) is the membrane The leaf surface is shown, and the right half (vertical/horizontal hatched part) shows the partition surface. In FIG. 1, separation membranes 8 are stacked on both sides of a disc-shaped membrane support 7, and the outer periphery is bonded with adhesive. The sealed disk-shaped separation membrane leaves are stacked at regular intervals via annular spacers 11, It is fitted and fixed to the hollow rotating shaft 4. There are radial grooves on both surfaces of the disc-shaped support 7. The permeate flow path formed between the separation membrane 8 and the separation membrane 8 lined with a non-woven fabric is The hollow rotating shaft 4 communicates with a hollow portion 10 of the rotating shaft through a small hole 6 provided therein. Also , a membrane element consisting of a membrane leaf and a hollow rotating shaft 4 is separated from the liquid by an annular spacer 11. tightly coupled. Between each membrane leaf is a diagram punched from a flexible film sheet. The annular partition 5 with both ears shown in 2 (right half) is inserted in advance, and the membrane element When storing and assembling the cylindrical container 1, the hole 12 should be parallel to the axis of the inner wall of the cylindrical container, and A supply flow path 13 and/or a discharge flow path for the liquid to be treated, which are provided in a groove shape at positions symmetrical about two axes. The rotation of the partition 5 is prevented by passing it through the anti-rotation rod 15 provided inside the partition 14. The membrane leaves are located between each membrane leaf in a state where displacement in the axial direction is free.

[0019] The liquid to be treated is supplied from the liquid inlet 2 provided at one end of the cylindrical container 1. It enters channel 13 with virtually no pressure drop and rotates with the surface of the rotating membrane leaf. It passes between the empty partitions 5, loses the membrane permeate and reaches the treated liquid discharge channel 14, where it is concentrated. The material flows out from the material discharge port 3.

[0020] The hollow rotating shaft 4 is supported by a bearing 16 and is connected to a drive belt (not shown) via a pulley 17. Rotated by a motor.

[0021] In this embodiment, the partitions 5 can be freely displaced in the axial direction, but a separate space is also provided between the partitions 5. It is also possible to fix the axial position at the position of the co-rotation prevention rod 15 by inserting a It is possible.

[0022]

[Effect of the idea]

This invention significantly reduces flow pressure loss by supplying and discharging the liquid to be treated in parallel. The effect increases approximately in proportion to the square of the number of membrane leaves.

[0023] In other words, the device of the present invention and the conventional device in which the liquid to be treated is supplied and discharged in series are the same. Comparing cases where the same flow rate of liquid to be treated flows in with the number of membrane leaves, the present invention With parallel liquid supply, the supply flow rate is divided to each membrane leaf, so the flow rate is reduced. Compared to the conventional system where the entire amount is supplied to each membrane leaf, the supply per membrane leaf is reduced. The pressure drop reduction effect is approximately proportional to the number of membrane leaves due to a decrease in the supply amount, and the flow path length Compared to the conventional method, in which the number of layers is multiplied by the length of the membrane leaf, the inventive method has the same number of layers as the length of the membrane leaf. Coupled with the pressure drop reduction effect that is approximately proportional to the number of membrane leaves due to the leaf length , and has the effect of reducing pressure loss due to very few bends in the flow path. be.

[0024] In addition, by connecting the partitions with the supply and discharge channels, the membrane leaf and container can be closed. In addition to reducing the clearance and making it more compact, it is also possible to If the membrane leaf is flexible, the membrane leaf and and/or the partition flexes and expands the flow path, making it possible to pass through the blockage. This can be expected to be effective in preventing flow path blockages.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of an apparatus showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a cross section of the device of the present invention.

FIG. 3 is a longitudinal cross-sectional side view of a conventional rotary membrane separator.

[Explanation of symbols]

1 Cylindrical container 2 Liquid inlet 3 Concentrate outlet 4 Hollow rotating shaft 5 Partition 6 small hole 7 Disc-shaped membrane support 8 Separation membrane 9 Inside the membrane leaf 10 Rotating shaft hollow part 11 Annular spacer 12 holes 13 Supply channel 14 Discharge channel 15 Co-rotation prevention rod 16 Bearing 17 Pulley

Claims (4)

[Scope of utility model registration request] Claim 1: A hollow rotary shaft is provided with membrane leaves at regular intervals, which are provided with separation membranes on both sides of a flat support having a membrane permeate flow path therein, and whose outer periphery is liquid-tightly sealed. The permeate flow path of the membrane leaf and the hollow part of the hollow rotating shaft communicate with each other through a small hole in the rotating shaft wall, and a membrane element that is liquid-tightly sealed from the outside is rotated into a container. In a rotary membrane separator that has fixed flat partitions between the membrane leaves, the supply flow path and discharge flow are structured so that the liquid to be treated is supplied to and discharged from each membrane leaf in parallel. 1. A rotary membrane separation device, characterized in that a channel is provided in the container in parallel with a rotation axis. 2. The rotary membrane separation apparatus according to claim 1, wherein the supply flow path and the discharge flow path are provided at positions facing each other symmetrically with respect to the rotation axis. 3. The rotary membrane separator according to claim 1, wherein the flat partition is flexible and movable in the direction of the rotation axis. 4. The rotary membrane separator according to claim 1, wherein the prevention of co-rotation of the flat partitions is achieved by anchoring means provided in the supply channel and/or the discharge channel.