JPH0356126A - Hollow yarn membrane filter having desalting function - Google Patents

Abstract

PURPOSE:To make desalting function excellent by fixing both ends of hollow membrane yarns to the water gathering parts on the inflow and outflow sides of a liquid to be treated provided to a hollow yarn membrane filter and filling the water passing pipe connecting both water gathering parts with a filler having desalting function. CONSTITUTION:In the structure of a hollow yarn membrane filter 3 separating a particulate solid and a dissolved ion component by hollow yarn membranes 7, water gathering parts 12a, 12b are provided to the filter 3 on the inflow and outflow sides of a liquid to be treated thereof. Both ends of the hollow yarn membranes 7 are fixed to both water gathering parts and the water passing pipe 11 connecting both water gathering parts if filled with a filler 18 having desalting function. As a result, solid separating function and dissolved component removing function can be provided to the hollow yarn membrane filter and the contact time of a dissolved component and an ion exchange material can be extended and, by this method, the hollow yarn membrane filter excellent in desalting function is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hollow fiber membrane filter used for purifying cooling water in, for example, nuclear power plants and thermal power plants.

[Conventional technology]

In nuclear power plants, in order to suppress the radiation dose around the reactor, it is necessary to remove iron oxides and dissolved substances called crud, which are impurities in the condensate, in advance.
As removal equipment, 'rJjJ over desalination equipment, desalination equipment, etc. are installed. A filtration demineralizer is a device in which a rod-shaped element is precoated with powdered ion exchange resin, and the ion exchange resin is captured within the precoat layer. Although it is possible to remove crud using this method, there are problems such as operational aspects such as pre-coating operations being troublesome, backwashing frequency being short, and the problem of generating a large amount of waste ion exchange resin.

On the other hand, a hollow fiber membrane filter is available as a method that does not require a bricoating aid. This filter is made up of a module consisting of several thousand hollow fiber membranes made of a polymeric material such as polyethylene and each having a diameter of about 1 mm. There are those that use a layer of microfiltration membrane with pores of 1 μm, and those that use a layer of ultrafiltration membrane that has even smaller pores. This hollow fiber membrane filter separates fine solids such as cladding, and allows dissolved substances to pass through the pores. Therefore, this filter cannot remove dissolved components.

By the way, attempts have been made to improve the above-mentioned hollow fiber membrane filter and to remove dissolved substances in the condensate of nuclear power plants using this hollow fiber membrane filter.

In this method, ion exchange groups are added to the hollow fiber membrane itself, and all sulfone groups (ski11),
There are films that provide functional groups such as carboxylic acid groups (Cool) (for example, Japanese Patent Publication No. 56-57836, 62-8300).
No. 6). Although it is possible to desalt or remove dissolved ion components by an ion exchange reaction using such a membrane, the membrane is thin and the residence time within the membrane is short, making it impossible to perform sufficient ion exchange. Furthermore, sufficient ion exchange cannot be carried out because it is not possible to sufficiently impart functional groups to the membrane due to the reduction in strength.

On the other hand, a layer of porous ion-exchange resin membrane is polymerized on the hollow fiber membrane, and non-meltable impurities in the condensate are removed on the surface of the hollow fiber filtration membrane, and molten impurities are removed from the ion-exchange membrane. There are purifiers that purify water by ion exchange as it passes through.

(JP-A-62-129109, 63-65910, 63-296803). Among these purifying devices, Japanese Patent Publications Nos. 62-129109 and 63-296803 are similar to those mentioned above in Japanese Patent Publication Nos. 56-57836 and 62-8300.
Similar to No. 6, the ion exchange resin membrane layer formed on the hollow fiber rod is formed thinly from the viewpoint of strength, etc., so the residence time in the membrane is short and sufficient ion exchange cannot be performed. Also, JP-A-63-6
In No. 5910, an ion exchange resin layer is provided on the upper part of the hollow fiber membrane filter, and since a sufficient filling height of the ion exchange material cannot be secured in the filter container, the contact time of the liquid to be treated is short and the removal rate is low. small.

[Problem to be solved by the invention]

As mentioned above, conventional hollow fiber membrane filters have poor removal efficiency of dissolved components because the contact time between dissolved components and ion exchange material is short. The purpose of the present invention is to provide a hollow fiber membrane filter with the ability to remove solid content and remove dissolved components, and to prolong the contact time between the dissolved components and the ion exchange material, thereby improving the desalination function. The purpose is to provide an excellent hollow fiber membrane filter.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a structure for a hollow fiber membrane filter that separates particulate solid content and dissolved ion components. A water collection part is provided on the outflow side, and both ends of the hollow fiber membrane are fixed to both water collection parts.
It is characterized in that the water pipe connecting the outflow side water collection part and the inflow side water collection part is filled with a filler having desalination ability.

The water pipe filled with the filler material may be a water collection pipe provided to guide the liquid to be treated that has entered the water collection part on the inflow side to the water collection part on the outflow side, or may be a water collection pipe provided separately from the water collection pipe. A desalting tube may be provided in which the inside of the provided tube is filled with a filler having desalting ability.

The material of the water pipe is incinerated, such as plastic or rubber.

Further, as the filler having desalting ability, an ion exchange resin or ion exchange fiber comprising a cation exchanger or an anion exchanger is used.

More specifically, the hollow fiber membrane filter can be configured as follows. That is, both ends of the hollow fiber membrane are fixed to water collection tanks provided on the inflow and outflow sides of the liquid to be treated in the filter container, and the ends of the hollow fiber membrane are opened into both water collection tanks to connect the two water collection tanks. The inside of the water collection pipe is filled with a filler that has desalination ability. Alternatively, the ends of the hollow fiber membranes fixed to the outflow side water collection tank may be closed, and only the ends fixed to the inflow side water collection tank may be opened to the inflow side water collection tank.

The hollow fiber membrane filter described above can be used in cooling water purification systems of nuclear power plants and thermal power plants. In other words, nuclear power or thermal power generation involves introducing steam generated in a nuclear reactor or boiler to a power generation turbine, driving it, cooling it in a condenser, liquefying it, guiding it to a feedwater heater, and then circulating it back to the reactor or boiler. In a power generation plant, the hollow fiber membrane filter having a desalination function of the present invention may be interposed in the flow path between the condenser and the feed water heater.

Furthermore, the hollow fiber membrane filter of the present invention can be used in ultrapure water production equipment. The ultrapure water production process includes, for example, raw water → pretreatment → reverse osmosis membrane (filter) → ion exchange resin (
The order is: demineralizer) → ultraviolet irradiation (organic matter decomposition) → ion exchange resin (demineralizer) → precision membrane (filter). The hollow fiber membrane filter of the present invention can be used by being incorporated into a part of the treetop path. For example, by using the above-mentioned hollow fiber membrane filter in the combination of the ion-exchange resin demineralizer and the precision filter installed in the two Sai-Hiragi routes, the efficiency of ultrapure water production can be increased and the equipment can be made more compact. I can do it.

[Function] When the liquid to be treated flows into the inside of the hollow fiber membrane from the outside, the solid content in the liquid is removed, and when it passes through the water passage pipe that connects the inflow side and the outflow side, the desorption inside the pipe is removed. The molten substances are removed by the salt-capable filler.

〔Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a system in which the hollow fiber membrane filter of the present invention is applied to a condensate purification system of a nuclear power plant. In the figure, steam generated in a nuclear reactor 1 drives a turbine 2 for power generation, is cooled by a condenser 5, and then circulates into the reactor 1 through a water supply heak 4. In this case, if there are impurities in the cooling water, they may be converted into radioactive substances within the reactor l or cause corrosion of piping materials, so it is necessary to purify the water as much as possible. As a purification device, a hollow fiber membrane filter 3 is used to simultaneously separate solid content such as cladding and dissolved ion components.
is installed in front of the water supply heater 4.

FIG. 2 shows the structure and system of the hollow fiber membrane filter according to the invention. In the figure, a large number of hollow fiber membrane modules 17 are loaded into a filter container 19.

The module 17 is installed on a fixed temporary 6 above the filter container 19, and several thousand hollow fiber membranes 7 are fixed thereon. At the bottom of the filter container 19 is a disperser 8 used for backwashing.
is installed. Condensate from the condenser 5 shown in FIG. 1 flows in through the inlet 9 at the bottom of the container, passes through the hollow fiber membrane 7 of each module 17, and flows out through the outlet 10 at the top.

Next, the structure and function of the hollow fiber membrane module 17 will be explained in the third section.
This will be explained using figures. The module 17 includes a hollow fiber membrane 7 and a desalination column l1 formed by filling a water collection pipe with a desalination material.
It has a structure in which both ends thereof are fixed to respective water collecting tanks 12a and 12b on the inflow side and outflow side of the liquid to be treated (condensate). Nets for fixing the packing material are provided at the upper and lower parts of the desalting column 11, and ion exchange resin or ion exchange fiber is filled between them. The amount of filling material is adjusted by the diameter and filling height of the desalting column 11, and the number of columns. A replaceable package type can also be used for the desalting column 11. In Fig. 3, both ends of the hollow fiber membrane 7 are opened into the water collection tanks 12a and 12b on the inflow side and the outflow side, but as shown in Fig. 4(b), it is fixed to the water collection tank 12b on the outflow side. The end of the thread membrane may be occluded.

Examples of the flow direction of condensate are shown in Figures 4(a) and (
Shown in b). In Figure (a), both ends of the hollow fiber membrane 7 are open to water collection tanks 12a and 12b on the inflow side and outflow side, water enters the inside from the outer surface of the membrane, is divided into two in the vertical direction, and is separated into water collection tanks 12a and 12b on the inflow side. The water that has entered 12a passes through the desalination column 11, enters the water collection tank 12b on the outflow side, and is discharged upward.

In this embodiment, only about 50% of the liquid to be treated passes through the desalting column 11. Note that 18 is a filler.

On the other hand, in FIG. 4(b), since the end of the hollow fiber membrane 7 fixed to the water collection tank 12b on the discharge side is closed, all of the water that has entered the membrane is collected in the water collection tank 12a on the inflow side. , flows out to the top through the desalting column 11. In this embodiment, the entire amount of the liquid to be treated passes through the desalting column 11 and is desalted, but since the entire amount passes through the membrane tube, the pressure loss is greater than in the split flow system shown in FIG.

Next, an experimental example demonstrating the present invention will be described.

FIG. 5 shows an outline of the experimental apparatus. This experimental device consists of a hollow fiber membrane filter l3, a raw water tank 14, and two liquid concentration adjustment tanks 15. Hollow fiber membrane filter 1 consisting of 16 and
3 specifications are hollow fiber membrane (1.2φX300mm pore diameter 0
．． 1μm) 100 lines, and the filtration area is looO
cffl. The desalting column 11 is a hollow fiber membrane filter 1
It consists of a cylindrical tube of lOφ×300 mm placed in the center of the tube, and 20 ml of each of cationic resin and anionic resin are filled inside the tube. Raw water tank 14 corresponded to the experimental conditions. The liquid can be adjusted, and here, the NaCl solution stored in one concentration adjustment tank l5 and the iron oxide particle-containing liquid stored in the other concentration adjustment tank l6 can be injected into the raw water tank 14. There is. Using this experimental device, we determined the desalination performance and pressure drop characteristics of a hollow fiber membrane filter.

Experimental Example I The desalting performance of two hollow fiber membrane filters with different liquid flow path directions shown in FIG. 6(a), 0)) was tracked by changes in the conductivity at the filter outlet. The stock solution has a NaCl concentration of 10■/l
, liquid was passed through at a rate of 160 Il/h. Figure 6 shows the change in electrical conductivity at the filter outlet over time. In the figure, (a) shows the average value of the population concentration, (b) shows the outlet concentration of the entire collection water hollow fiber membrane filter (structure shown in Figure 4 (b)), and (C) shows the partial water collection with both ends open. The outlet concentration of the filter (structure of FIG. 4(a)) is shown. As can be seen from FIG. 6, the full water flow system shown in b has a higher desalination rate than the partial water flow system. On the other hand, the amount of desalination is greater in the partial water flow method than in the panoramic water flow method. This is thought to be because in the case of partial water flow, the flow rate within the desalting column 11 is low, so the desalting rate within the desalting column 11 increases accordingly, and the total amount of desalting increases. .

Experimental Example ■ Using a panoramic water collection filter, the desalination characteristics of a liquid containing iron oxide particles and NaCl and the change in pressure loss of the filter were determined, and the change characteristics are shown in FIG. The treatment conditions were NaC
NJ degree 10■/l, iron oxide particles (α-Fe20i, l
tlIIl) Concentration 2! 50% of the solution containing Ilg/e
Water was passed at a rate of ff/h. The filter outlet conductivity is the same as the characteristic shown in FIG. 6 when NaCI water is passed through alone, indicating that desalination is occurring. On the other hand, the change in pressure drop increases as iron oxide particles are trapped on the membrane surface.

From this, the size (diameter, length) of the desalter column and water flow conditions should be selected in consideration of the desalination rate and amount of desalination as the filter structure.

〔Effect of the invention〕

According to the present invention, since the hollow fiber membrane filter can be provided with a desalting function, solid content separation and ion removal in the liquid to be treated can be performed simultaneously.

In cases where solid content separation is the main purpose and a desalination function is also required, such as in cooling water purification systems for nuclear power plants, thermal power plants, etc., a separator using a hollow fiber membrane and a demineralizer are recommended. Since treatment can be carried out using only the hollow fiber membrane filter of the present invention without separately providing a salt container, the number of necessary purification devices can be reduced, which is advantageous in terms of space and cost.

Furthermore, since the present invention utilizes a water pipe provided in the water collection part of a hollow fiber membrane filter and fills the inside with a filler having desalination ability, the filler should be sufficiently high and covered with water. Since the contact time with the treatment liquid can be extended, the desalting performance can be improved compared to conventional hollow fiber membranes in which ion exchange groups are added. Furthermore, if the desalting function section is configured with an exchangeable column, there is an advantage that the necessary treatment performance can be satisfied without performing an operation to regenerate the ion exchanger. The present invention has the same advantages as described above when used in an ultrapure water production apparatus.

[Brief explanation of drawings]

Figure 1 is a diagram of a BWR type nuclear power plant cooling water purification system using the hollow fiber membrane filter of the present invention, Figure 2 is a structural diagram of the hollow fiber membrane filter, and Figure 3 is the structure of the module of the hollow fiber membrane filter. Figures 4 (a) and (b3 do not show the liquid flow system due to the difference in module structure); Figure 5 is a configuration diagram of the experimental apparatus used in the present invention; Figure 6 is a hollow Fig. 7 is a processing characteristic diagram of the thread membrane filter and a characteristic diagram of the filter processing characteristic and pressure loss change. l...Reactor 2...Turbine 3...
Hollow fiber membrane filter 4... Water supply heater 5... Condenser 7... Hollow fiber membrane 11... Desalination columns 12a, 12b... Inflow side, outflow side water collection tank 17...
・Hollow fiber membrane module l8...Filling material 19...Filter container

Claims (1)

[Scope of Claims] 1. In the structure of a hollow fiber membrane filter that separates particulate solid content and dissolved ionic components by a hollow fiber membrane, a water collection part is provided on the inflow side and the outflow side of the liquid to be treated of the filter, and both 1. A hollow fiber membrane filter having a desalting function, characterized in that both ends of the hollow fiber membrane are fixed to a water collecting part, and a water pipe connecting the two water collecting parts is filled with a filler having a desalting ability. 2. The hollow fiber membrane filter having a desalination function according to claim 1, wherein the water flow pipe is a water collection pipe that connects an inflow side and an outflow side water collection section. 3. The hollow fiber membrane filter having a desalination function according to claim 1, wherein the water flow pipe is a desalination pipe provided separately from the water collection pipe. 4. The hollow fiber membrane filter having a desalination function according to claim 1, wherein the material of the water pipe is an incinerated material such as a plastic material or a rubber material. 5. The hollow fiber membrane filter having a desalting function according to claim 1, wherein the filler having a desalting function is an ion exchange resin or an ion exchange fiber comprising a cation exchanger and an anion exchanger. 6. The hollow fiber membrane filter having a desalting function according to claim 1, wherein the liquid to be treated flows into the membrane from the outside of the hollow fiber membrane, and further, a part or all of it passes through a water pipe. . 7. Fix both ends of the hollow fiber membrane provided in the container to the inflow and outflow side water collection tanks for the liquid to be treated, and provide both ends open to the inside of the tank to form the inflow and outflow side water collection tanks. A hollow fiber membrane filter having a desalination function, characterized in that a filler having a desalination function is filled inside connected water collecting pipes. 8. Connect both ends of the hollow fiber membrane provided in the container to the inflow and outflow water collection tanks for the liquid to be treated, close the ends of the hollow fiber membrane fixed to the outflow water collection tank, and close the inflow water collection tank. Desalination characterized by opening the end of a hollow fiber membrane fixed to the tank into the tank, and filling the inside of the water collection pipe that connects the water collection tanks on the inflow side and the outflow side with a filler having a desalination function. Hollow fiber membrane filter with functions. 9. In a nuclear power plant, the steam generated in a nuclear reactor is guided to a power generation turbine to drive it, then cooled in a condenser, liquefied, guided to a feed water heater, and then circulated back to the reactor. A nuclear power generation plant, characterized in that a hollow fiber membrane filter according to any one of claims 1 to 8 is interposed in a flow path between the reactor and the water supply heater. 10. In a thermal power generation plant in which steam generated in a boiler is guided to a power generation turbine to drive it, then cooled and liquefied in a condenser, guided to a feed water heater, and then circulated to the boiler again, the condenser A thermal power generation plant characterized in that the hollow fiber membrane filter according to any one of claims 1 to 8 is interposed in a flow path of a water supply heater. 11. An ultrapure water production apparatus comprising a plurality of components such as a filter for passing raw water, a demineralizer, and an ultraviolet irradiation device for decomposing organic matter contained in raw water, in which a part of the purification route is provided as claimed in claim 1. 9. An ultrapure water production apparatus characterized in that the hollow fiber membrane filter according to any one of 8 above is interposed therein.