JPH07232037A - Membrane separation apparatus - Google Patents

Abstract

PURPOSE:To provide a membrane separation technology which can extend the life of a separation membrane and reduce administration costs. CONSTITUTION:In a membrane separation apparatus, RO modules 3a-3d are placed in a container main body l, both ends of which are closed by main body covers 2a, 2b, multistagewise in the axial direction through brine seals 4a-4d, raw water 20 which is pressurized from a raw water inlet pipe 13 to a concentrated water outlet pipe 15 is passed, and permeated water 20b is recovered through water collecting pipes 16a-16d and a permeated water outlet pipe 14. Pipe seats 6a-6e communicating with the front and rear of each of the RO modules 3a-3d, a pressure equalizer 11 which makes the pipe seats 6a-6e communicate, a constant flow valve 7, control valves 8a-8d, partition valves 10a-10d, and pressure gauges 9a-9e are installed on the periphery of the container main body 1, enabling monitoring the pressure differences between the front and rear of each of the RO modules 3a-3d and operations to reduce the pressure differences by adjusting the openings of the control valves 8a-8d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane separation technique, and more particularly to a reverse osmosis membrane (R
O) A technology effective when applied to a module or the like.

[0002]

2. Description of the Related Art RO modules have undergone technological development as a method for obtaining fresh water from seawater, and are now an indispensable constituent element for ultrapure water production equipment in the field of semiconductor production. Also, in the medical field, it is used for artificial dialysis and the like, and the field of application is increasing.

The RO module in the ultrapure water production facility is roughly classified into a front stage type and a rear stage type depending on the installation position in the facility. That is, there are a pre-stage type installed in the front stage of the ion exchange tower and a post-stage type installed in the rear stage.

For example, in the latter-stage type, colloidal silica, fine suspended matter, suspended matter and the like in raw water such as industrial water are removed by a pretreatment device at a constant ratio.
The remaining portion enters the RO module while being dissolved in the raw water. The RO module is an RO membrane having a deionization function, a support mechanism for supporting the RO membrane, a support mechanism and the RO membrane.
It is composed of a spacer for securing a flow path of raw water between the membranes.

The cause of the differential pressure between the raw water inflow side and the concentrated water outflow side in the RO module is that the spacer part on the raw water inflow side is blocked. Especially, in the case of the front stage RO module having a large raw water load, The raw water inflow side passage is blocked by the scale components such as silica and calcium, and slime such as bacteria and suspended substances. Especially, the spacer that secures the space of the raw water inflow side passage is RO
Since it has a mesh shape for the purpose of promoting diffusion of permeated water on the membrane, once scale or slime adheres and accumulates, it is difficult to recover the initial state even if chemical cleaning is performed. is there.

Although the differential pressure during operation of the RO module varies depending on the membrane structure and the like, a fixed reference value is set, and it is important to operate within that range, but it exceeds the reference value. If such an operation operation is performed, the RO module will be irreversibly buckled, and cannot be reused.

In order to prolong the life of the RO module, in addition to water quality control such as deionization, TOC (total organic carbon) and particle removal performance, and film surface control related to the amount of permeated water, the inflow of raw water described above is performed. The differential pressure control on the side is important.

In the prior art, when an increase in the differential pressure occurs, there is no effective method other than chemical cleaning, and the cleaning effect can hardly be expected. Therefore, it is important for management to carry out regular cleaning to avoid the occurrence of differential pressure as much as possible.

Regarding the RO module incorporated in the conventional ultrapure water facility, etc., for example, "Electronic Materials" 19 published by Industrial Research Institute Co., Ltd., November 20, 1984.
No. 1984, reprint, P135-P139, etc.

[0010]

As mentioned above, in particular,
In the pre-stage RO module, the load of deionization, TOC, and particulate removal operations is large, and the raw water inflow side of the RO module is likely to be blocked. Therefore, as in the conventional method, recovery is simply performed by measures such as chemical cleaning. However, there is a concern that the reduction of the flow rate of raw water and the increase of the differential pressure at the inlet and outlet of the RO module are unavoidable, and the excessive differential pressure causes the irreversible buckling failure of the RO module, making it unusable.
Further, in order to avoid this buckling failure, it is necessary to wash the RO module more frequently than necessary.

An object of the present invention is to extend the life of the separation membrane and manage the operation without increasing the cleaning frequency of the separation membrane more than necessary and avoiding an excessive increase in the differential pressure before and after the separation membrane. It is to provide a membrane separation technology capable of realizing cost reduction.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0013]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

That is, in the membrane separation device of the present invention, a pipe connecting the raw fluid inflow side and the concentrated fluid outflow side, and the raw fluid moving from the raw fluid inflow side to the concentrated fluid outflow side via this pipe. And a flow path control means for controlling at least one of the pressure and the flow rate.

Further, the membrane separation apparatus of the present invention has a multi-stage structure in which the concentrated fluid outflow side of the preceding stage is connected to the raw fluid inflow side of the next stage, and the raw fluid inflow side and the final stage of each stage are connected via the pipeline. The concentrated fluid outflow side is connected in common, and the flow path control means is arranged for each stage.

Further, in the membrane separation apparatus of the present invention, the raw fluid is raw water, the separation membrane is a reverse osmosis membrane module, and the raw water is produced by sequentially passing through a plurality of reverse osmosis membrane modules arranged in multiple stages. Pure water is obtained as the fluid.

Further, in the membrane separation apparatus of the present invention, the membrane separation apparatus is arranged before the ion exchange tower in the ultrapure water production facility.

Further, in the membrane separation apparatus of the present invention, pipe seats communicating with the raw water inflow side and the concentrated water outflow side of the reverse osmosis membrane module are installed on the outer circumference of the pressure vessel accommodating the plurality of reverse osmosis membrane modules. , Connect each pipe seat to each other via a pipe,
A pressure control valve for controlling the differential pressure between the raw water inflow side and the concentrated water outflow side of each reverse osmosis membrane module is arranged on the pipeline.

Further, in the membrane separation apparatus of the present invention, it is arranged at the front stage of the ion exchange column in the ultrapure water production facility.

[0020]

According to the above-described membrane separation apparatus of the present invention, the differential pressure before and after the separation membrane, that is, the raw fluid inflow side and the concentrated fluid outflow side are monitored during operation, and the differential pressure exceeds a certain value. In this case, the flow path control means provided in the pipe connecting the raw fluid inflow side and the concentrated fluid outflow side is operated to adjust the pressure and amount of the raw fluid that bypasses the separation membrane, Is controlled so as to be maintained below a predetermined specified value.

As a result, the separation membrane cleaning operation for avoiding the increase in the differential pressure as described above is not performed more frequently than necessary, and the separation membrane is irreversibly damaged due to excessive differential pressure. It is possible to extend the life of the separation membrane and reduce the cost required for management and operation without incurring the problem.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic sectional view showing the structure of a membrane separation apparatus which is an embodiment of the present invention.

The storage container body 1 has a hollow cylindrical shape, and both ends thereof are covered with a body cover 2a and a body cover 2b. The main body covers 2a and 2b are fastened to both end surfaces of the storage container main body 1 with bolts and nuts (not shown), and the raw water inlet pipe 13 is attached to the main body cover 2a.
Further, a permeated water outlet pipe 14 and a concentrated water outlet pipe 15 are integrally projected on the main body cover 2b.

Inside the storage container body 1, a plurality of RO modules 3a to 3d are stored in multiple stages in the axial direction.
In the gap between the outer peripheral surface of each of the RO modules 3a to 3d and the inner peripheral surface of the storage container body 1, the raw water 2 in the gap is provided.
Brine seals 4a to 4d for preventing the leakage of 0 are attached.

By the plurality of brine seals 4a to 4d and the plurality of RO modules 3a to 3d, the storage container body 1 is formed.
Of the RO modules 3a to 3d are divided, and the concentrated water 20a formed by the raw water 20 passing through the RO modules of each stage is forcibly used as the raw water 20 in the RO module of the next stage. It has a structure that flows into.

Each of the RO modules 3a to 3d has a porous water collecting pipe 16a to 16d at the center thereof, and each of the water collecting pipes 16a to 16d is press-fitted into the connectors 5a to 5c so as to be mutually connected. Is air-tightly connected to the end cap 12
The main body cover 2b side end is connected to the permeated water outlet pipe 14 penetrating the main body cover 2b.

Raw water 20 as a target of deionization and further removal of impurities such as TOC and fine particles is forced to flow into the storage container body 1 via the raw water inlet pipe 13 by a pressurizing mechanism (not shown). Inner peripheral surface of storage container body 1 and RO
Since the gap on the outer peripheral surface of the module 3a is closed by the brine seal 4a, the raw water 20 flowing into the storage container body 1 is forcedly passed through the RO module 3a, and a part of the raw water 20 is deionized or TOC Clean permeated water 20b is obtained by removing impurities such as fine particles.
Then, it enters the inside of the porous water collection pipe 16a and moves to the side of the next-stage water collection pipe 16b connected by the connector 5a.

On the other hand, of the raw water 20 supplied to the RO module 3a, the part that did not permeate the RO module 3a and flow into the water collection pipe 16a, that is, the part that did not become the permeated water 20b, is the permeated water 20b. The concentrated water 20a in which ions, impurities, etc. are concentrated by the generated amount becomes the concentrated water 20a that passes through the RO module 3a in the axial direction, and the RO module 3 of the next stage
Raw water 20 flows into b.

The above-mentioned operation is performed by the RO module 3b.
The permeated water 20b is sent through the permeated water outlet pipe 14 to the device at the subsequent stage. Also concentrated water 20
The a is discharged out of the system through the concentrated water outlet pipe 15.

In this case, on the outer peripheral surface of the storage container body 1,
A plurality of RO modules 3 arranged and stored in multiple stages in the axial direction
a to 3d, between the RO module 3a and the main body cover 2a located at both ends, and the RO module 3
A plurality of pipe seats 6a to 6e that communicate with respective positions between d and the main body cover 2b are arranged.

The plurality of pipe seats 6a to 6e are common to the equalizing pipe 1.
1, and each of the pipe seats 6a to 6e is provided with a plurality of sluice valves 10a to 10d provided in the path of the pressure equalizing pipe 11.
It is configured such that mutual communication and disconnection are performed by. Further, pressure gauges 9a to 9e are provided in the respective areas partitioned by the plurality of sluice valves 10a to 10d, and pressures on the inflow side and the outflow side of the raw water 20 (concentrated water 20a) in the RO modules 3a to 3d are provided. Is measurable.

The raw water inlet pipe 13 is provided on the pipe seat 6a on the most upstream side.
A constant flow valve 7 is provided for guiding a part of the raw water 20 flowing into the storage container body 1 to the pressure equalizing pipe 11. The raw water 20 in the pressure equalizing pipe 11 is provided at the pipe seats 6b to 6e on the downstream side thereof. Flow rate control valves 8a to 8d are provided for introducing the above and below the RO modules 3b to 3d.

An example of the operation of this embodiment will be described below.

Raw water 2 pressurized through the raw water inlet pipe 13
0 into the storage container main body 1 and forcefully pass through the plurality of RO modules 3a to 3d in order to perform deionization,
When the permeated water 20b is produced by performing the TOC removal operation and the like and is supplied to the outside through the permeated water outlet pipe 14, and when a part of the concentrated water 20a is discharged from the concentrated water outlet pipe 15, the RO module The inlet side of the raw water 20 (concentrated water 20a) in each of 3a to 3d is blocked due to scale, slime, etc., and a pressure loss occurs between the RO modules 3a to 3d, which causes a difference between before and after the individual RO modules 3a to 3d. Pressure is generated.

This differential pressure increases if left unattended, and eventually leads to irreversible buckling damage of the RO modules 3a to 3d. Therefore, in the case of the present embodiment, the differential pressure control operation is performed as follows.

First, the differential pressure in the RO modules 3a to 3d is measured, and it is monitored whether or not each is within the reference value. That is, at the time of normal operation, the constant flow valve 7 is set to a predetermined opening, and the sluice valves 10a ...
10d is fully closed, and the flow rate control valves 8a to 8d are fully open. In this state, by observing the pressure gauges 9a to 9e, the raw water 20 and the concentrated water 20a before and after each of the RO modules 3a to 3d are observed. Measure the pressure.

For example, the differential pressure of the RO module 3b is
The pressure difference between the pressure gauges 9b and 9c is monitored, and when the pressure difference is equal to or higher than the reference value, the differential pressure of the RO module 3b is adjusted. First,
The flow rate control valves 8a-8d that are currently fully open are fully closed,
Only the gate valves 10a and 10b are fully opened. Pressure equalizing pipe 11
The pressure inside the pipe is equal to the raw water 2 on the inlet side of the RO module 3a
The pressure becomes 0, and the pressure gauges 9a to 9c indicate the same pressure. R
Regarding the differential pressure of the O module 3b, the flow rate control valve 8b is gradually opened and the high-pressure raw water 20 in the pressure equalizing pipe 11 is introduced to the outlet side of the RO module 3b to reduce the pressure difference between the inlet side and the outlet side.

When the differential pressure of the RO module 3d at the final stage is increased, first, the partition valves 10a to 10d are fully opened and the flow rate control valves 8a to 8d are fully closed. afterwards,
The flow control valve 8d is gradually opened while measuring the difference between the indicated values of the pressure gauges 9d and 9e, and the high-pressure raw water 20 in the pressure equalizing pipe 11 is allowed to flow into the outflow side of the RO module 3d from the pipe seat 6e. By introducing the high-pressure raw water 20 to the outflow side of the RO module 3d in this way, the differential pressure before and after the RO module 3d is reduced.

As described above, according to the membrane separation apparatus of this embodiment, in the plurality of RO modules 3a to 3d that are stored in the storage container main body 1 in multiple stages, any RO is provided by blocking the raw water passage side or the like. When a differential pressure is generated in the modules or all the RO modules 3a to 3d, the plurality of sluice valves 10a to 10d and the flow rate control valve 8a are always kept in the operating state without any troublesome measures such as operation stop and cleaning. The RO module 3 is operated by the operation such as ~ 8d.
It is possible to reliably avoid failures such as breakage of a to 3d. As a result, by extending the life of the RO modules 3a to 3d and reducing the frequency of cleaning work, it is possible to reduce the cost required for the management operation of the membrane separation device.

The invention made by the present inventor has been specifically described based on the embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the raw fluid may be a fluid other than water. The separation membrane is not limited to the reverse osmosis membrane, and may be an ultrafiltration membrane or the like. Further, the pressure gauge, the flow rate control valve, and the sluice valve may be connected to a microcomputer or the like to automatically perform a series of differential pressure control operations as described above.

[0043]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, according to the membrane separation apparatus of the present invention,
Without increasing the frequency of cleaning the separation membrane more than necessary, it is possible to avoid an excessive rise in the differential pressure before and after the separation membrane, extend the life of the separation membrane, and reduce the cost required for management and operation. The effect of, is obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of a membrane separation device that is an embodiment of the present invention.

[Explanation of symbols]

1 Storage container main body 2a Main body cover 2b Main body cover 3a to 3d RO module (separation membrane) 4a to 4d Brine seal 5a to 5c Connector 6a to 6e Pipe seat (pipe line) 7 Constant flow valve (flow passage control means) (pressure control) Valve) 8a-8d Flow rate control valve (flow path control means) (pressure control valve) 9a-9e Pressure gauge 10a-10d Gate valve (flow path control means) (pressure control valve) 11 Pressure equalizing pipe (pipe line) 12 End cap 13 Raw Water Inlet Pipe 14 Permeate Outlet Pipe 15 Concentrated Water Outlet Pipe 16a to 16d Water Collection Pipe 20 Raw Water (Raw Fluid) 20a Concentrated Water (Concentrated Fluid) 20b Permeated Water (Production Fluid)

Claims (6)

[Claims] 1. A membrane separation apparatus for obtaining a production fluid from which at least one of impurities and ions in the raw fluid is removed by pressurizing the raw fluid through a separation membrane, wherein the raw fluid inflow side And a flow path control means for controlling at least one of a pressure and a flow rate of the raw fluid moving from the raw fluid inflow side to the concentrated fluid outflow side via the pipeline. A membrane separation device comprising: 2. The concentrated fluid outflow side of the preceding stage has a multi-stage structure in which it is connected to the original fluid inflow side of the next stage, and the concentrated fluid outflow side of each stage and the concentrated fluid outflow side of the final stage are provided via said conduit. 2. The membrane separation apparatus according to claim 1, wherein the sides are connected in common and the flow path control means is arranged for each stage. 3. The raw fluid is raw water, the separation membrane is a reverse osmosis membrane module, and the raw water is passed through a plurality of the reverse osmosis membrane modules arranged in multiple stages in sequence to produce a pure production fluid. Water is obtained, The membrane separation apparatus of Claim 1 or 2 characterized by the above-mentioned. 4. The membrane separation apparatus according to claim 1, wherein the membrane separation apparatus is arranged before the ion exchange tower in the ultrapure water production facility. 5. A pipe seat communicating with a raw water inflow side and a concentrated water outflow side of the reverse osmosis membrane module is installed on the outer periphery of a pressure vessel accommodating a plurality of reverse osmosis membrane modules, and the pipe seat is provided with a pipe line. And a pressure control valve for controlling the differential pressure between the raw water inflow side and the concentrated water outflow side of each of the reverse osmosis membrane modules, which is connected to each other via a membrane. Separation device. 6. The membrane separation apparatus according to claim 5, wherein the membrane separation apparatus is arranged in a stage before the ion exchange tower in the ultrapure water production facility.