JPH0747236A - Membrane separation apparatus and membrane module - Google Patents

Abstract

PURPOSE:To control the operation of a membrane separation apparatus by rapidly detecting a leak even when a separation membrane is damaged and to suppress the contamination of a transmitted component or the lowering of the concn. rate of a component to be conc. CONSTITUTION:When a first separation membrane 1 is damaged, the fluid to be treated leaked from the separation membrane 1 of a first module 2 is supplied to a second module 4 equipped with a second separation membrane 3 having an average pore size larger than that of the first separation membrane 1. The coarse component in the fluid to be treated blocks up the pores of the second separation membrane 3 and, on the supply side and/or transmission side of the second separation membrane 3, pressure or a flow rate varies corresponding to the leak of the fluid to be treated. This variation is detected by a pressure detection means 13 or a flow rate detection means and a control means controls the supply of the fluid to the first module 2 and/or the second module 4 in response to the detection signal from the detection means. Therefore, the leak is rapidly detected and the contamination of a transmitted component or the lowering of the concn. rate of a component to be conc. as the leak of the fluid to be treated can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane separator and a membrane module useful for separating gas and liquid.

[0002]

2. Description of the Related Art In recent years, river water and lake water filtration, seawater desalination, nuclear condensate filtration, dialysis water purification, blood filtration, artificial dialysis, pharmaceutical water and semiconductor water purification, fruit juice concentration and Purification, concentration and filtration of enzymes and bacteria, filtration of human waste and drainage,
In various fields such as gas separation and concentration, liquid degassing, liquid-liquid extraction, and organic solvent recovery, membrane separation utilizing the permeability of the membrane is performed. For these membrane separations, a membrane separation device equipped with a hollow fiber type, a spiral type, a tube type, a pleated type, a plate-and-frame type, or another type of membrane module is usually used.

On the other hand, in membrane separation, if an accident such as membrane breakage occurs, the fluid to be treated leaks from the supply side of the membrane,
It flows into the permeate side of the membrane untreated. In particular, when treating a contaminated fluid to be treated or a fluid to be treated containing particulate matter, the contamination of the permeation component is significant. Moreover, when a concentrated component is used by membrane separation, a predetermined membrane separation efficiency cannot be maintained, and the degree of concentration is reduced.

For this reason, attempts have been made to improve the durability of the separation membrane itself, but a separation membrane having sufficient durability can be obtained especially in the internal pressure system in which the fluid to be treated is pressurized and supplied. Not not. Further, instead of the defect of the film itself, the film may be damaged due to a trouble on the device, a pretreatment performed in the previous stage of the film module, or the like to cause a leak.

Therefore, it is necessary for the membrane separation apparatus as a whole to promptly detect a trouble involving a leak and control the operation of the apparatus. As a method of detecting such a leak from the membrane module, for example, (1) a method of detecting by the turbidity of the permeated liquid, (2) a method of detecting by the number of fine particles of the permeated liquid, etc. have been proposed. However, in all of these methods, rapid detection is difficult, and the methods for detecting turbidity and the number of fine particles cannot be applied to a clear fluid to be treated. Therefore, the types of applicable fluids to be processed and the uses of the apparatus are limited. In addition, the detection equipment is expensive and the cost of the apparatus is high.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to prevent contamination of permeated components and a decrease in concentration rate of concentrated components even if the separation membrane is damaged, and to treat regardless of the type of fluid to be treated. It is intended to provide a membrane separation device and a membrane module capable of efficiently detecting a trouble and controlling the operation.

Another object of the present invention is to provide a membrane separation device and a membrane module which are inexpensive and can be applied to various uses.

[0008]

As a result of various investigations, the present inventors have arranged a second separation membrane having a specific separation ability on the permeation side of the separation membrane, and have the pressure or flow rate of the fluid to be treated increased. It was found that the above object can be achieved by providing a means for detecting the above, and the present invention has been completed.

That is, the membrane separation device of the present invention has a first separation membrane for separating a fluid to be treated and an average pore diameter larger than that of the first separation membrane, and permeates through the first separation membrane. A second separation membrane through which a fluid can pass, a means for detecting the pressure or flow rate on the supply side and / or the permeation side of the second separation membrane, and a first signal in response to a detection signal from this detection means. And a control means for controlling the supply of the fluid to the separation membrane and / or the second separation membrane.

Further, the membrane module of the present invention has a first separation membrane element for separating a fluid to be treated and an average pore diameter larger than the average pore diameter of the first separation membrane element. It is provided with a second separation membrane element through which the fluid permeated from the membrane element can pass, and means for detecting the pressure or flow rate on the supply side and / or the permeation side of the second separation membrane element.

In the present specification, the "average pore size" means the average size corresponding to the size of the permeation component. For example,
In the case of a precision filtration membrane, the size of the permeation component can be represented by the average pore size. On the other hand, for example, in ultrafiltration membranes and reverse osmosis membranes, it is difficult to measure the pore size. Therefore, in the case of ultrafiltration membranes, the size of the permeation component is usually expressed by the molecular weight cutoff. In the case of a reverse osmosis membrane, it is usually expressed as a salt elimination rate (salt removal rate). Therefore, in the present specification, for example, the term "average pore size" is used for convenience, including expressions that represent the size of the permeation component, such as the molecular weight cutoff in the ultrafiltration membrane and the salt exclusion rate in the reverse osmosis membrane.

[0012]

In the above-mentioned membrane separation device or membrane module, the separation ability of the second separation membrane or the separation membrane element (hereinafter, the separation membrane or the separation membrane element may be simply referred to as a separation membrane) is important. Play a role. That is, in a normal state where the fluid to be treated does not leak, the fluid to be treated is separated by the first separation membrane, and at least part of the permeated fluid is supplied to the second separation membrane. Since the second separation membrane has a larger average pore size than the first separation membrane, the fluid is not substantially separated, and the pressure loss generated during the filtration separation is small.

However, should the first separation membrane be damaged, the second separation membrane provided on the permeation side restricts the permeation of a component having a specific size. In other words, the components of a certain size or more contained in the fluid to be treated that have leaked from the first separation membrane have their permeation regulated by the second separation membrane, so that the contamination of the permeation components can be suppressed and the damage caused by troubles can be suppressed. Can be minimized.

Further, a pressure loss occurs due to the filtration separation of the fluid by the second separation membrane. That is, when the fluid is filtered and separated by the second separation membrane, the pressure loss corresponding to the pore diameter of the second separation membrane and the component whose permeation is regulated block the pores of the second separation membrane. Due to pressure loss. Therefore, if the fluid to be processed leaks from the first separation membrane,
In the second separation membrane, a pressure difference and a flow rate difference of the fluid occur between the supply side and the permeation side. For example, on the supply side of the second separation membrane, the pressure and the flow rate of the fluid to be treated increase compared to the steady state, and on the permeate side of the second separation membrane, the pressure and the flow rate of the fluid to be treated decrease. . Such a change in the pressure or flow rate of the fluid to be treated corresponds to a trouble caused by the leak, and the trouble is promptly detected by the detecting means. That is, since the pressure detection means and the flow rate detection means have higher detection sensitivity than the turbidity and particle number detectors, leaks can be detected quickly. Further, the pressure detecting means and the flow rate detecting means are inexpensive, and the cost of the membrane separation device and the membrane module can be kept low.

Then, in response to the detection signal from the detection means, the control means controls the supply of the fluid to the first separation membrane and / or the second separation membrane. Corresponding to the leak, the permeation of the permeation component and the reduction of the concentration can be promptly suppressed when the concentration component is used.

Further, when the effective membrane area of the second separation membrane is 50% or less of the effective membrane area of the first separation membrane, coarse components such as solid particles in the fluid to be treated are the first. It quickly accumulates in the second separation membrane, greatly reducing the ventilation or liquid permeability. Therefore, the contamination of the permeated component can be efficiently suppressed, the rate of change in pressure or change in flow rate increases, and these can be detected more reliably and quickly. In addition, the effective membrane area means a region substantially related to ventilation or liquid permeability.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in more detail below with reference to the accompanying drawings.

FIG. 1 is a schematic view showing an example of the membrane separation apparatus of the present invention.

The membrane separation device is connected to a first module 2 provided with a first separation membrane 1 which controls the first stage filtration separation, and a permeation side (secondary side) of the first module 2. The second module 4 is connected via a line 5 and includes a second separation membrane 3. The second separation membrane 3 has a larger average pore diameter than the first separation membrane 1. On the supply side (primary side) of the first module 2,
A supply line 8 having a pump 7 for supplying the treated fluid stored in the storage tank 6 is connected, and
The component (concentrated liquid) that has not passed through the first separation membrane 1 is circulated to the storage tank 6 through the circulation line 9.

In the connection line 5 connecting the transmission side of the first module 2 and the supply side of the second module 4,
An electromagnetic valve 10 for controlling the flow rate is provided, and a return line 11 leading to the storage tank 6 branches from the connection line 5 on the upstream side of the electromagnetic valve. An electromagnetic valve 12 is provided on the return line 11.

The connection line 5 is provided with a pressure detector 1 for controlling the opening and closing of the electromagnetic valves 10 and 12.
3 is provided. As shown in FIG. 2, the pressure detector 1
The detection signal from 3 is supplied to the comparison circuit 14 for comparison with the reference value Vf. The reference value Vf is set corresponding to the pressure in a normal state where the fluid to be processed does not leak. The comparison circuit 14 controls the control circuit 1 when the detected value V from the pressure detector 13 exceeds the reference value Vf (V> Vf).
A control signal is given to the AND circuit 16 of No. 5. The AND circuit 16 is also supplied with an operation signal from the control circuit 18 of the pump 7 according to the operation of the apparatus.

The signal from the AND circuit 16 passes through the inverter 17 and the electromagnetic valve 10 of the connection line 5.
It is also given to the drive circuit 19 for controlling the opening / closing of the solenoid valve, and is also given to the drive circuit 20 for controlling the opening / closing of the electromagnetic valve 12 of the return line 11. The signal from the AND circuit 16 is also given to the control circuit 18 of the pump 7.

In such a membrane separation apparatus, when the pump 7 is operated to process the fluid to be processed by the first and second modules 2 and 4, during steady operation, the valve 12 of the return line 11 is closed and connected. The component that has permeated the first module 2 when the valve 10 of the line 5 is opened and operated is supplied to the second module 4 through the connection line 5. At this time, since the second separation membrane 3 does not have a substantial separation function for the separation component in the fluid to be treated, the permeation component permeates the second separation membrane 3 without causing a pressure loss. And then spill.

In the unlikely event that a leak occurs, a component having a specific size or more contained in the fluid to be treated which leaks from the first separation membrane 1 is permeated by the separation ability of the second separation membrane 3. Since it is regulated, the contamination of the permeation component can be suppressed. In addition, the component whose permeation is restricted closes the holes of the second separation membrane 3, and the pressure of the fluid to be treated on the supply side of the second separation membrane 3 becomes high.

When the pressure detector 13 detects an increase in pressure, that is, a leak of the fluid to be processed from the first separation membrane 1, the control circuit 15 causes the control circuit 15 to output the control signal from the comparison circuit 14 and the pump 7. In response to the operation signal, a drive signal is given to drive circuits 19 and 20 for opening and closing the electromagnetic valves 10 and 12, and the electromagnetic valve 10 on the connection line 5 is closed.
The electromagnetic valve 12 of the return line 11 is opened. Also, AND
In response to the signal from the circuit 16, the pump control circuit 18
Stops the operation of the pump 7. Therefore, the fluid to be treated that has leaked from the first separation membrane 1 can be suppressed from flowing into the permeation side of the second separation membrane 3, and contamination of permeation components can be prevented.

FIG. 3 is a schematic view showing another example of the membrane separation device of the present invention. In the device shown in FIG. 3, the permeation side of the first module 22 having the first separation membrane 21 and the supply side of the second module 24 having the second separation membrane 23 are connected by a connection line 25. Connected, this connection line 25
In the outflow line 31 branched from the second module 2
An electromagnetic valve 30 is provided to control the flow rate of fluid to the valve 4. A flow rate detector 33 for controlling the operation of the pump 27 provided in the supply line 28 is provided on the transmission side of the second module 24.

In this example, during steady operation by operating the pump 27, the degree of opening / closing of the electromagnetic valve 30 in the outflow line 31 is adjusted, and a part of the component that has passed through the first separation membrane 21 is passed through the connection line 25. To the second module 24, and the rest flows out through the outflow line 31. The components that have not passed through the first separation membrane 21 circulate in the storage tank 26 through the circulation line 29.

The electrical configuration of this device is the same as that shown in FIG. 2 except for the following points. That is, (1) without providing drive circuits 19 and 20 for opening and closing the electromagnetic valve 10 of the connection line 5 and the electromagnetic valve 12 of the return line 11 of FIG. 2, respectively (2) detected value by the flow rate detector 33 When V becomes less than the reference value Vf (V <Vf) set corresponding to the flow rate in the normal operation, the comparison circuit 14 gives a control signal to the AND circuit 16 of the control circuit 15 and the AND circuit. A control signal for stopping the operation of the pump 27 is given from 16 to the control circuit 18. The control circuit 18 of the pump 27 may be directly supplied with the control signal from the comparison circuit 14 without passing through the AND circuit 16.

In such an apparatus, for example, the storage tank 26
If a leak occurs from the first separation membrane 21 during the treatment of the liquid to be treated by the first module 22, the second separation membrane 23 is clogged with holes, etc. The flow rate of the fluid on the permeate side of the module 24 decreases. Therefore, similarly to the above, in response to the control signal from the AND circuit 16, the pump control circuit 18 stops the operation of the pump 27.

In the membrane separation device of the present invention, at least a part of the permeation component permeated by the first separation membrane may be supplied to the second separation membrane. For example, in the membrane separation device shown in FIG. 3, as described above, a part of the permeation component is subjected to the separation of the second separation membrane, and the rest of the permeation component is transferred to the outside of the system without passing through the second separation membrane. It may flow out, or the entire amount of the permeation component may be supplied to the second separation membrane.

In the above example, one first and second module provided with a separation membrane are connected in series. However, (1) between a plurality of first modules connected in series. May be connected to at least one second module. In this case, even if the component leaked from the first separation membrane permeates the second separation membrane, the predetermined component can be separated by the first separation membrane arranged on the downstream side of the second separation membrane. Therefore, the permeation component is not contaminated.

(2) The first and second modules connected in series may be arranged in parallel. In this case, a common supply line may be connected to the supply side of each first module, and a common outflow line may be connected to the transmission side of each second module. In such a device, not only can the fluid to be processed be efficiently separated by the plurality of first separation membranes arranged in parallel, but by any chance,
Even if the fluid to be treated leaks from the first separation membrane, by closing one series of electromagnetic valves composed of the first and second modules connected in series, other series will be greatly affected. The fluid to be treated can be treated without giving it.

Further, (3) the aspects (1) and (2) may be combined. That is, at least one second module is interposed between a plurality of first modules connected in series to configure one processing series, and
A plurality of the processing series may be connected in parallel.

In the above example, the first separation membrane and the second separation membrane respectively form different modules, but the same module, that is, the first separation membrane and the second separation membrane, is used. The provided module may be configured.

Further, in the membrane separation apparatus of the present invention, the control means may control the operation of at least one of the solenoid valve and the pump in response to the signal from the comparison means.

The membrane module of the present invention comprises a first separation membrane element having a filtration separation function, a second separation membrane element for catching a leak from the first separation membrane, and the leak detection. Pressure detection means or flow rate detection means. Such a membrane module is compact, and a membrane separation device similar to that described above can be configured only by mounting it on the separation device.

FIG. 4 is a schematic sectional view showing an example of a membrane module using hollow fiber membranes as the first separation membrane element and the second separation membrane element.

The membrane module comprises a first separation membrane element 41 composed of a hollow fiber bundle composed of a plurality of hollow fiber membranes.
And a second separation membrane element 42 which is arranged on the permeation side thereof and which is composed of a hollow fiber bundle composed of a plurality of hollow fiber membranes having a larger average pore diameter than the first separation membrane element 41. I have it.

Both ends of the separation membrane elements 41, 42 are
Each of them is fixed by the sealing and fixing portion 43 in a state where its end face is open, and is disposed inside the casing 44. In addition,
The first separation membrane element 41 and the second separation membrane element 42 are fixed in different areas of the sealing and fixing portion 43. The sealing and fixing portion 43 is formed by embedding and adhering the gap between the separation membrane elements 41 and 42 with a sealing agent such as epoxy resin or polyurethane.

Lids 45a and 45b are provided in the openings at both ends of the casing 44, and the inner surfaces of the lids 45a and 45b are brought into contact with the sealing and fixing portion 43 to seal them. In addition, convex partition walls 46a and 46b for partitioning the opening area of the first separation membrane element 41 and the opening area of the second separation membrane element 42 are formed.

Since the membrane is separated by the internal pressure system in which the fluid to be treated is pressurized and supplied to the hollow portion of the first separation membrane element 41, the opening area of the first separation membrane element 41 in the one cover 45a. A supply port 47a for supplying the fluid to be treated to the hollow portion of the first separation membrane element 41 is formed in a portion corresponding to the second separation membrane element 4
At a portion corresponding to the second opening area, an outlet port 48a is formed for letting out the component that has permeated the second separation membrane element 42 through the hollow portion. The first separation membrane element 4 is provided at a portion of the other lid 45b corresponding to the opening area of the first separation membrane element 41.
1 is formed with an outlet 47b for letting out the concentrated component that has not permeated the first separation membrane 1, and the second separation membrane element 42 is provided at a portion corresponding to the opening region of the second separation membrane element 42.
An outlet port 48b is formed for allowing the component that has permeated through the hollow portion to flow out through the hollow portion.

Therefore, the supply port 47 of one lid 45a
The to-be-processed fluid from a is supplied to the hollow part of the 1st separation membrane element 41, and the component which did not permeate | transmit the 1st separation membrane element 41 flows out from the outflow port 47b of the other cover body 45b. Moreover, since the second separation membrane element 42 has a larger average pore diameter than the first separation membrane element 41, at least a part of the components that have passed through the first separation membrane element 41 is accompanied by a large pressure loss. Without
The second separation membrane element 42 smoothly flows into the hollow portion from the outer surface, and through the hollow portion, flows out from the outlets 48a and 48b of the lids 45a and 45b. In the process of permeating through the second separation membrane element 42, the components permeating through the first separation membrane element 41 are filtered and separated.

The casing 44 is formed with an outlet 49 for letting out the component that has permeated the first separation membrane element 41, and at the supply side of the second separation membrane element 42, that is, the first separation membrane element 42. In order to detect the pressure on the permeate side of one separation membrane element 41, the outlet 4
A pressure detector 50 is attached to 9.

The sealing and fixing portion 43 and the casing 4
4 and the lids 45a and 45b are hermetically sealed by a sealing means such as an elastic O-ring or packing. Moreover, you may airtightly seal between the sealing fixing | fixed part 43 and the convex partition walls 46a and 46b of lids 45a and 45b by a sealing means.

Further, between the casing 44 and the sealing fixing portion 43, and between the sealing fixing portion 43 and the convex partition walls 46a and 46b.
In between, the sealing means may be bonded and sealed by an adhesive, for example, a sealing means such as a resin similar to the resin of the sealing and fixing portion, instead of or together with the sealing means. .

When such a membrane module is used, when the fluid to be treated leaks from the first separation membrane element 41, the permeation component is contaminated by the filtration separation action of the second separation membrane element 42, as described above. The decrease in the concentration rate of the concentrated component and the concentration component is suppressed, and the second separation membrane element 42 is
The pressure loss on the supply side, in other words, on the permeation side of the first separation membrane element 41 increases. Then, the pressure fluctuation in the membrane module can be detected by the pressure detector 50 in correspondence with the leak.

Such a membrane module is shown in FIG.
When installed in a membrane separation device having control means as shown in FIG. 2, the pressure detection means or the flow rate detection means promptly detects a leak, and the fluid is supplied to the membrane module or the device through the control means. It is possible to control the operation of and improve safety.

FIG. 5 is a schematic sectional view showing another example of the membrane module of the present invention. Elements and members that are common to the membrane module of FIG. 4 will be described with the same reference numerals.

In the membrane module shown in FIG. 5, (1) the rib 55a on one side to which the fluid to be treated is supplied is not provided with the protruding partition wall and the outlet, and (2) the second separation. The end of the membrane element 52 on the side of the lid 55a is the sealing and fixing portion 53.
Except that the end face opening is closed and (3) one outlet is formed in the casing 54 and the pressure detector 60 is attached to the outlet.
It is configured similarly to the membrane module shown in FIG.

FIG. 6 is a schematic sectional view showing an example of a membrane module in which a hollow fiber membrane is used as the first separation membrane element and a tubular porous body is used as the second separation membrane element. Elements and members common to the membrane module of FIG. 5 will be described with the same reference numerals.

In this membrane module, both ends of the second cylindrical separation membrane element 62 having a large diameter are sealed and fixed by the sealing and fixing portions 63a, 63a.
63b, which is embedded in a substantially central portion of the 63b and has openings at both ends closed, (2) A first separation membrane element 61 composed of a plurality of hollow fibers around the second separation membrane element 62.
(3) The opening area of the first separation membrane element 61 and the opening area of the second separation membrane element 62 are provided in the lid 65b arranged at the other end of the casing 54. And a cylindrical partition wall 66b that defines a flow path for a component that has permeated the second separation membrane element 62 is formed. (4) The first separation membrane element 61 is provided on the lid 65b. Two outlets 67a and 67b for letting out the concentrated component that did not permeate, and an outlet 68 for letting out the component that has passed through the second separation membrane element 62.
The membrane module has the same structure as that of the membrane module shown in FIG.

Also in the membrane modules of FIGS. 5 to 6, the fluctuations of pressure and flow rate due to the leak of the fluid to be treated are detected by the detecting means in the same manner as described above, and the contamination of the permeated component and the concentration degree of the concentrated component are detected. Can be suppressed.

FIG. 7 is a schematic sectional view showing another example of the membrane module. In this membrane module, a first separation membrane element 71 composed of a bundle of a plurality of hollow fibers is accommodated in a hollow cylindrical second separation membrane element 72. The first separation membrane element 71 is fixed to the sealing fixing portions 73a and 73b in a state where both end surface openings thereof are opened, and the both ends of the second separation membrane element 72 are sealing fixing portions 73a and 73b. It is buried with the end face closed. The sealing fixing portions 73a and 73b are arranged in an airtight or liquid-tight manner in a casing 74 in which an outlet 79 for letting out a component that has permeated the second separation membrane element 72 is formed. The lids 75a, 75
b is provided.

A supply port 77a for supplying the fluid to be treated to the hollow portion of the first separation membrane element 71 is formed in one lid 75a, and the first separation membrane is formed in the other lid 75b. An outlet port 77b is formed for letting out the concentrated component that has not passed through the element 71. Further, in the other lid 75b, a portion inside the hollow portion of the second separation membrane element 72 and corresponding to the non-opening region of the first separation membrane element 71, that is, on the supply side, A hollow-cylindrical partition wall 76b is formed to partition the opening region of one separation membrane element 71, and communicates with this hollow-cylindrical partition wall 76b to let out a component that has passed through the first separation membrane element 71. The outflow port 78b is formed. A pressure detector 80 or a flow rate detector for detecting the pressure and the flow rate on the permeate side of the first separation membrane element 71 is provided at the outflow port 78b.

In such a membrane module, the fluid to be treated is supplied to the hollow portion of the first separation membrane element 71, and the component that has permeated the first separation membrane element 71 is separated into the hollow cylindrical second separation membrane element. The component supplied to the hollow portion (supply side) of the membrane element 72 and permeated through the second separation membrane element 72 flows from the outside (permeation side) of the second separation membrane element 72 to the flow provided in the casing 74. Exit 79
Outflow. Therefore, when a leak occurs, the pressure and the flow rate inside the hollow portion of the second separation membrane element 72 increase, and the fluctuation of the pressure and the flow rate is detected by the pressure detector 80.
Alternatively, it is detected by a flow rate detector.

Further, since the first separation membrane element is housed in the second separation membrane element, the first separation membrane element can be protected by the second separation membrane element and the volume of the membrane module can be reduced. it can.

Further, the first separation membrane element 71 and the second separation membrane element 72 of the membrane module may be protected by protective means such as a protective cylinder or a protective net, if necessary. The protection means can be formed of a material having large mechanical strength and shape retention, such as plastic, metal, or ceramics.

In such a membrane module, in order to facilitate maintenance such as replacement, the first separation membrane element 71 and the second separation membrane element 72 form a cartridge having a sealing and fixing portion. Is preferred. In this case, even if the separation membrane element is damaged, it can be easily replaced with a new cartridge.

The first separation membrane and the second separation membrane are not limited to both ends, and at least one end surface may be closed as shown in FIG.

In the membrane separation device and the membrane module of the present invention, contrary to the above, the external pressure for supplying the fluid to be treated to the outer surface side (primary side) of the first separation membrane (element) composed of the hollow fiber. The method may be used. In this case, on the downstream side of the membrane module including the first separation membrane (element), the second separation membrane (element) and the pressure are applied to the portion corresponding to the end face opening region of the first separation membrane (element). A second membrane module equipped with a detection means or a flow rate detection means is provided in series, and the hollow portion (secondary side) of the first separation membrane (element) is fed to or permeated by the second separation membrane (element). To communicate with
Fluctuations in pressure and flow rate may be detected by the detection means.

As is clear from the above, the feature of the present invention resides in that the first separation membrane (element) and the second separation membrane (element) are arranged in combination in a specific positional relationship.

The second separation membrane (element) has an average pore size larger than that of the first separation membrane (element) and has a separation performance in which impurities of a specific size do not permeate. The average pore diameter of the second separation membrane (element) may be larger than the average pore diameter of the first separation membrane. Usually, it is 2 times or more, preferably 5 times or more, more preferably 10 times or more with respect to the average pore diameter of the first separation membrane, and
It is less than or equal to μm, preferably less than or equal to 100 μm, and more preferably less than or equal to 50 μm. When the average pore diameter of the second separation membrane (element) is not more than twice the average pore diameter of the first separation membrane (element), the pressure loss during steady operation by the second separation membrane is large. Further, when the average pore diameter exceeds 500 μm, the separation efficiency by the second separation membrane (element) is low, and it becomes difficult to suppress the contamination of the permeation component by the fluid to be treated that has leaked through the first separation membrane (element). In addition to that, it becomes difficult to quickly detect a pressure change or a flow rate change due to a leak.

The average pore diameter of the second separation membrane (element) differs depending on its type and the use of the device. For example, a hollow fiber membrane is used as the first separation membrane (element),
When a gas separation membrane or a reverse osmosis membrane having an average pore diameter of about 0.0005 to 0.005 μm is used, the average pore diameter of the second separation membrane (element) may be about 0.005 to 10 μm. As a separation membrane (element) of 0.
When using an ultrafiltration membrane of about 001 to 0.1 μm, the average pore diameter of the second separation membrane (element) is 0.01 to 1
It may be about 00 μm. When using a microfiltration membrane having an average pore diameter of about 0.1 to 8 μm, the average pore diameter of the second separation membrane (element) may be about 1 to 100 μm.

The second separation membrane (element) usually has an average pore diameter of 0.1 to 500 μm, preferably 0.1 to 1
It has a hole of about 00 μm, and more preferably about 0.1 to 50 μm. When the pore size of the second separation membrane (element) is less than 0.1 μm, the pressure loss increases.

The preferred second separation membrane element has 5
It comprises an asymmetric membrane having a support layer and a skin layer having a large number of pores of not more than 00 μm, preferably 0.01 to 100 μm, more preferably 0.1 to 50 μm, and covers the first separation membrane element. A cylindrical membrane disposed on the. The support layer can be formed of a woven or non-woven fabric of fibers and constitutes a porous layer having relatively large pores. The cylindrical membrane composed of the asymmetric membrane has a large pressure resistance against the supply pressure of the fluid to be treated, and thus has a protective effect on the first separation membrane element.

Further, the effective membrane area of the second separation membrane (element) is usually 50% or less (for example, 0.5 to 50%) of the effective membrane area of the first separation membrane (element),
It is preferably 1 to 20%, more preferably about 1 to 10%. If the effective membrane area of the second separation membrane (element) deviates from the above range, the rate of pressure change and flow rate change of the fluid to be treated at the time of leak becomes small, and it becomes difficult to detect the trouble quickly. On the other hand, when it exceeds 50%, the permeation component is likely to be contaminated due to damage of the first separation membrane (element) or the like.

When the flow rate detecting means is used, the lower limit of the effective membrane area of the second separation membrane (element) is not particularly limited as long as the fluid flows smoothly. It may be 0.1% or less of the effective film area.

In the present invention, the types and materials of the first separation membrane (element) and the second separation membrane (element) are not particularly limited. Examples of the type include a hollow fiber type, a spiral type, a plate and frame type, a tube type, a plate type, and the like, a membrane module, a membrane cartridge, and the like. Above all, a hollow fiber membrane is preferable as the first separation membrane (element) from the viewpoints of compactness and strength of the membrane itself. As the second separation membrane (element), a hollow fiber membrane, a tube type porous body membrane or the like is preferable.

The material of the first separation membrane (element) is, for example, polyethylene, ethylene-propylene copolymer, polypropylene, poly-4-methylpentene-1.
Fluorine-containing polymers such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers; cellulose acetate Cellulosic polymers such as; polyvinyl chloride; polyacrylonitrile; polymethylmethacrylate,
Acrylic polymer such as acrylonitrile-methyl methacrylate copolymer; silicone resin; polyamide; polyimide; polyethersulfone; polysulfone; polyphenylene oxide; polyphenylene sulfide; polyarylate; polyetheretherketone; polyetherimide; polycarbonate; polyvinyl alcohol Examples thereof include polymers such as polymers.

As the material for the second separation membrane (element), in addition to the above-mentioned polymers, various materials that can be vented or passed, for example, woven cloth, non-woven cloth, metal such as stainless steel, and ceramics. And so on.

These materials may be used alone or in combination of two or more. The method of making it porous is not particularly limited,
For example, in addition to a conventional film forming method such as phase separation and stretching, a method such as sintering, assembling fibrous materials or woven cloth may be used.

As the separation membrane, various membranes, such as a non-porous membrane, a porous membrane, and the like, depending on the type of separation component and the separation method,
A composite film or a modified film can be used. Also, the types of the first separation membrane (element) and the second separation membrane (element),
The shape and material may be the same or different. For example, as shown in FIGS. 6 and 7, a hollow fiber membrane may be used for the first separation membrane element and a tubular porous membrane may be used for the second separation membrane element to form a membrane module. In addition, they can be used in appropriate combination depending on the application.

Each of the first separation membrane and the second separation membrane may be a single membrane or a combination of a plurality of membrane modules, membrane elements and the like. For example, in the membrane module of the present invention, a plurality of membrane elements may be detachably arranged in the casing.

If necessary, the first separation membrane element and the second separation membrane element are subjected to surface treatment such as treatment with an organic solvent, plasma discharge treatment, corona discharge treatment, and ion treatment, and then adhesive sealing. You may use it.

The type of sealant (adhesive) that seals the end of the separation membrane is not limited, and examples thereof include epoxy resin, vinyl ester resin, urethane resin, olefin polymer, silicone resin, and fluorine-containing resin. Can be mentioned.

The shape of the casing can be appropriately selected according to the application, etc., but is usually cylindrical in many cases. The material of the casing can be selected according to the fluid to be treated and the type of separated component, and examples thereof include plastics such as polyvinyl chloride, polycarbonate, (meth) acrylic polymer, polysulfone and polyether sulfone; metals such as stainless steel; It may be ceramics or the like. The casing is often made of polysulfone, polyethersulfone, stainless steel, or the like.

In the embodiment shown in the figure, since the pressure detecting means and the flow rate detecting means are used, a nozzle or the like is not provided in the casing of the membrane module, but a nozzle is provided in the casing for removing bubbles in the module. May be provided, and such a nozzle may be openable and closable.

Another feature of the present invention is that the first and second separation membranes (elements) are combined with the detection means for detecting fluctuations in pressure and flow rate as described above. The pressure detecting means or the flow rate detecting means is not particularly limited, and can be appropriately selected depending on the type of the fluid to be treated, the separation method, and the like.

Examples of the pressure detecting means include a Breton tube type pressure detector, a capacitance type pressure sensor, a semiconductor strain gauge type (piezoresistive effect type) pressure sensor, and a capacitance type pressure sensor. Of these, a Breton tube type pressure detector, a semiconductor strain gauge type pressure sensor and the like are preferable.

When the pressure detecting means is used, the pressure on at least one of the supply side and the permeation side of the second separation membrane may be detected, but the primary side (supply side) of the second separation membrane.
It is preferable to use the differential pressure type detection means for detecting the pressure difference between the fluid to be processed between the secondary side (permeation side) and the secondary side because the leak can be detected with higher sensitivity and speed.

As the flow rate detecting means, for example, an electromagnetic flowmeter such as a small and lightweight electromagnetic flowmeter or an intelligent electromagnetic flowmeter equipped with a microcomputer; an ultrasonic flowmeter such as a propagation time difference method, a Doppler method; a piezoelectric element, a strain An example is a Karman vortex flowmeter equipped with a detection element such as a gauge, a thermistor, or an ultrasonic sensor. Among them, a Karman vortex flowmeter which can be applied to any of liquid, gas and vapor and which can detect the flow rate in a non-contact manner is preferable.

The flow rate detecting means can be arranged on either the supply side or the permeation side of the second separation membrane, but it is often arranged on the permeation side of the second separation membrane.

The fluid to be treated can be selected according to the separation characteristics of the first separation membrane, and a fluid containing gas or liquid such as air, oxygen and nitrogen can be used. As the liquid, water, alcohols, ethers, esters, ketones, organic acids, amines, aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, etc. Can be mentioned.

The membrane separation device and membrane module of the present invention are
For example, various separation methods such as reverse osmosis, ultrafiltration, pervaporation, ultrafiltration, precision filtration, etc. are used in various fields such as food, wastewater treatment, water purification, blood filtration, gas separation, etc. At
It can be suitably used for separation of liquid, separation of gas component from liquid, separation of gas, and the like. Among them, ultrafiltration, precision filtration and reverse osmosis method can be utilized and can be suitably used for separation of a liquid from a suspension or the like. In particular, it is suitably used in the fields where large troubles are likely to occur when leaking, such as the filtration of water for nuclear power and thermal power generation, drainage treatment, water purification treatment, filtration of human body fluid, and the like, where mass treatment is performed.

[0085]

According to the membrane separation apparatus and the membrane module of the present invention, since the first separation membrane, the second separation membrane and the means for detecting the pressure or the flow rate are provided, it is considered that the separation membrane is damaged. Also, it is possible to suppress the contamination of the permeated component and the decrease of the concentration rate of the concentrated component, and to minimize the damage caused by the trouble. In addition, since the leak from the first separation membrane can be quickly detected by the pressure detecting means or the flow rate detecting means, troubles can be detected efficiently regardless of the type of fluid to be processed, and control including stoppage of operation can be performed. Yes, the equipment is safe and reliable. Furthermore, since the average pore diameter of the second separation membrane is larger than that of the first separation membrane, there is no pressure loss during steady operation and the membrane separation efficiency does not decrease.

[0086]

【Example】

Examples 1 to 4 and Comparative Example 1 Tests were conducted using the membrane separation device shown in FIG. As the fluid to be treated, river water with a turbidity of 15 degrees was used. Comparison circuit 1
The reference value Vf at 4 is set to a pressure of 1.0 kg / cm ² G, and when the detected value V from the pressure detector 13 exceeds Vf, the drive circuits 19 and 20 respond to the signal from the control circuit 15. Then, the electromagnetic valve 10 of the connection line 5 was closed, and the electromagnetic valve 12 of the return line 11 was set to be opened.
As the first module 2 and the second module 4, the following modules were used in combination as shown in Table 1.

First module: A: Spiral type reverse osmosis membrane module (membrane area: 7
m ² , synthetic polymer membrane, salt removal rate: 98%, average pore size:
0.01 μm or less) [manufactured by Daicel Chemical Industries, Ltd., trade name: SV04-DRA9810] B: Hollow fiber type ultrafiltration membrane module (membrane area: 5 m ² ,
Polyethersulfone membrane, molecular weight cutoff: 30,000, average pore diameter: 0.01 μm or less) [manufactured by Daicel Chemical Industries, Ltd., trade name: FS10-FUS0382] C: Hollow fiber type ultrafiltration membrane module (membrane area: 5m ² ,
Cellulose acetate membrane, molecular weight cutoff: 150,000, average pore size: about 0.01 μm) D: Hollow fiber type precision filtration membrane module (membrane area: 3 m ² ,
Polyethersulfone membrane, average pore size: 0.1 μm) Second module: E: Hollow fiber type precision filtration membrane module (membrane area: 0.3 m
² , polyethersulfone membrane, average pore size: 0.2 μm F: Tube type porous membrane module (membrane area: 0.2 m
² , polymethyl methacrylate membrane, average pore size: 15μm)
[Manufactured by Daicel Chemical Industries, Ltd., product name: Pearlcon M
80] In Comparative Example 1, the membrane separation device was used without disposing the second module.

Further, in Example 1, the inlet pressure was 15
kg / cm ² , recovery rate 10%, inlet pressure 3 kg / cm ² , recovery rate 3 for Examples 2 to 4 and Comparative Example 1.
After operating the membrane separation apparatus for 30 minutes under the condition of 0 to 80%, the first separation membrane was damaged and then operated, and after a few minutes, the leak was detected and the operation of the apparatus was measured. The results are shown in Table 1.

[0089]

[Table 1] As is clear from Table 1, in each of the membrane separation devices of the examples, a leak was detected within 13 minutes, the device was activated, the electromagnetic valve 10 of the connection line 5 was closed, and the electromagnetic valve 12 of the return line 11 was Open. Therefore, the supply of the undiluted solution to the second module 4 was stopped, and the fluid to be treated leaked from the first separation membrane 1 was returned to the storage tank 6 through the entire return line 11. On the other hand, in the device of Comparative Example 1, no leak was detected and the device did not operate. Moreover, in the device of the example, even if a leak occurred, the turbidity of the permeated water of the second separation membrane was lower than that of the raw water.

Example 5 and Comparative Example 2 A test was conducted in the same manner as in Example 1 using the membrane separator shown in FIG. However, 20 of the permeated liquid of the first separation membrane 21
% Is supplied as a stock solution of the second separation membrane 23,
The degree of opening / closing of the electromagnetic valve 30 was adjusted. Second separation membrane 23
The flow rate detector 33 detects the flow rate of the permeated liquid, and when the flow rate of the permeated liquid falls to 30% of the normal operation, the control circuit is set to stop the pump 27 as a leak is detected. After damaging the first separation membrane, the pump 27
When the time required to stop was measured, the results shown in Table 2 were obtained.

[0091]

[Table 2] As is clear from Table 2, in the membrane separation device of the example, the leak can be quickly detected and the device can be operated.

[Brief description of drawings]

FIG. 1 is a schematic view showing a membrane separation device of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the apparatus shown in FIG.

FIG. 3 is a schematic view showing another example of the membrane separation device of the present invention.

FIG. 4 is a schematic cross-sectional view showing a membrane module of the present invention.

FIG. 5 is a schematic cross-sectional view showing another example of the membrane module of the present invention.

FIG. 6 is a schematic sectional view showing still another example of the membrane module of the present invention.

FIG. 7 is a schematic cross-sectional view showing another example of the membrane module of the present invention.

[Explanation of symbols]

 1, 21 ... First separation membrane 2, 22 ... First module 3, 23 ... Second separation membrane 4, 24 ... Second module 10, 12, 30 ... Electromagnetic valve 13, 50, 60, 80 ... Pressure detector 14 ... Comparison circuit 15 ... Control circuit 33 ... Flow rate detector 41, 61, 71 ... First separation membrane element 42, 62, 72 ... Second separation membrane element

Claims (9)

[Claims] 1. A first separation membrane for separating a fluid to be treated, and a second separation membrane which has a larger average pore diameter than the first separation membrane and through which the fluid permeated from the first separation membrane can pass. A separation membrane, means for detecting pressure or flow rate on the supply side and / or permeation side of the second separation membrane, and in response to a detection signal from the detection means, the first separation membrane and / or the second separation membrane. And a control means for controlling the supply of the fluid to the separation membrane. 2. The membrane separation device according to claim 1, wherein the first separation membrane and the second separation membrane constitute the same or different modules. 3. The membrane separation device according to claim 1, further comprising pressure detection means for detecting a pressure difference between the fluid supply side and the fluid permeation side of the second separation membrane. 4. The membrane separation device according to claim 1, wherein the average pore diameter of the second separation membrane is at least twice as large as that of the first separation membrane and not more than 500 μm. 5. The membrane separation device according to claim 1, wherein the effective membrane area of the second separation membrane is 50% or less of the effective membrane area of the first separation membrane. 6. A first separation membrane element for separating a fluid to be treated, and an average pore diameter larger than that of the first separation membrane element, so that the fluid permeated from the first separation membrane element can pass therethrough. A membrane module comprising a second separation membrane element and means for detecting a pressure or a flow rate on the supply side and / or the permeation side of the second separation membrane element. 7. The membrane module according to claim 6, further comprising pressure detection means for detecting a pressure difference between the fluid supply side and the fluid permeation side of the second separation membrane element. 8. The average pore size of the second separation membrane element is
More than twice that of the first separation membrane element, and 50
The membrane module according to claim 6, which has a thickness of 0 μm or less. 9. The membrane module according to claim 6, wherein the effective membrane area of the second separation membrane element is 50% or less of the effective membrane area of the first separation membrane element.