CN106458647B

CN106458647B - Method for operating regenerative ion exchanger

Info

Publication number: CN106458647B
Application number: CN201480079689.XA
Authority: CN
Inventors: 宮崎洋一; 福井长雄
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 2014-06-10
Filing date: 2014-06-10
Publication date: 2020-07-24
Anticipated expiration: 2034-06-10
Also published as: KR20170016844A; CN106458647A; KR102203041B1; WO2015189908A1

Abstract

The present invention provides a method for operating a regenerative ion exchanger, which is an economical method for operating a regenerative ion exchanger, wherein the method is characterized in that the operation of passing raw water in an upward flow manner is interrupted, and then the operation is restarted. A method for operating a regenerative ion exchange device in which an ion exchange resin 4 is accommodated in a container 1, comprising: a raw water feeding step of feeding raw water to the regenerative ion exchange device so as to flow upward, and a water feeding stopping step of stopping feeding raw water to the regenerative ion exchange device; after the raw water passage step is completed and before the water passage stopping step, there is a forced water passage step of causing forced water for pressing the ion exchange resin 4 downward in the container and moving the ion exchange resin layer to flow downward.

Description

Method for operating regenerative ion exchanger

Technical Field

The present invention relates to a method for operating a regenerative ion exchange device in which an ion exchange resin is contained in a container, and more particularly, to a method for operating a regenerative ion exchange device in which raw water is passed through an upward flow during water collection. More specifically, the present invention relates to an improvement in the process of stopping the water collection of the regenerative ion exchange device.

Background

As an operation method of a regenerative ion exchange device in which raw water is passed through a regenerative ion exchange device containing an ion exchange resin in a tank to obtain treated water, there is an upflow water-passing system in which raw water is passed through an upflow system.

Fig. 2a is a schematic vertical cross-sectional view showing the structure of the regenerative ion exchange device, and the cylindrical container 1 is provided with the cylinder axis direction as the vertical direction (particularly, the vertical direction). Porous plate-

like filter membranes

2 and 3 are provided in the upper and lower portions of the container 1, respectively, and an ion exchange resin 4 is accommodated between the

filter membranes

2 and 3. Since the ion exchange resin 4 is used, the resin itself swells and the volume thereof increases, and therefore, the increase in volume is usually expected to be accommodated in the container 1 with a space (free space portion F) having a predetermined height h remaining in the upper portion of the container 1.

When the raw water is passed through the raw water supply port 5 of the ion exchange resin so as to flow upward, the ion exchange resin 4 is pushed up by the water pressure, and as shown in fig. 2b, the fixed bed state of the filter membrane 2 pressed to the upper side is obtained, and water collection is performed in this state. The treated water flows out of the outlet 6 at the top of the container. When the flow of the raw water into the vessel 1 is stopped, the force pushing up the ion exchange resin 4 is removed, and therefore the ion exchange resin 4 forming the fixed bed is precipitated and dropped toward the lower filter 3 side in the vessel 1, and is restored to the storage state before the flow of the water, that is, the state shown in fig. 2 a.

When the ion exchange resin 4 is precipitated and dropped in the container 1 in this manner, as shown in fig. 2c, the ion exchange resin breakouts 4a are formed. The collapse parts 4a gradually move upward, finally reach the uppermost ion exchange resin 4, and the ion exchange resin 4 is dropped to return to the state shown in fig. 2 a. In the collapse parts 4a of the ion exchange resin, the ion exchange resin particles fall down while being mixed. Therefore, the ion exchange resin located at the lower side of the packed bed of the ion exchange resin 4 is broken (break), but in the state in the middle of the operation in which the ion exchange resin located at the upper side is not yet broken, the flow of raw water is stopped, and when water collection is stopped, the broken resin at the lower side is mixed with the unbroken resin at the upper side, and when the water collection operation is started again next time, the quality of the treated water may deteriorate.

Therefore, in the regenerative ion exchange device operating in a mode of collecting water in an upward flow and regenerating in a downward flow (counter-current regeneration mode), when water collection is started by the upward flow, water must be continuously passed until the water collection is completed (next regeneration).

Therefore, when it is desired to temporarily stop the regenerative ion exchange device, such as when the amount of pure water or ultrapure water used is reduced, it is necessary to perform a cyclic operation and to continuously operate the device, or to perform chemical regeneration, which takes a lot of time and cost.

As a means for suppressing fluidization of the ion exchange resin during upward-flow liquid introduction, as described in the upper right column of the second page of jp-a-51-77583, a method is known in which water is introduced in an upward-flow manner and at the same time, forced water (equilibrium water, downward flow) is introduced from above the resin bed to prevent the resin bed from rising. However, in this method, since the forced water is introduced from above the resin bed while the water is passed in an upward flow, the adjustment of the flow rate and the pressure becomes complicated. This method does not inhibit the disturbance of the resin layer due to natural precipitation when the water supply is stopped.

Paragraphs 0034 and 0035 of jp 2003-220387 disclose that the above problem can be solved by providing a movement adjusting mechanism to reduce the speed at which the ion exchange resin falls to the lower part of the resin cylinder when the water passage is completed. However, the method of providing such a movement adjusting mechanism requires a separate preparation and installation of the mechanism, and in a large-sized apparatus, particularly, the tower internal structure becomes complicated, which causes an increase in cost.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 51-77583;

patent document 2: japanese patent laid-open publication No. 2003-220387.

Disclosure of Invention

Problems to be solved by the invention

As described above, in the regenerative ion exchange device which collects water by passing water upward, when the fixed bed falls down while the water collection is temporarily stopped, the ion exchange resin layer is disturbed, and when the water collection is resumed, the water quality before the water collection is not always maintained. Therefore, the regenerative ion exchange device that collects water by passing water upward must be continuously operated even when the device is temporarily stopped in the middle of collecting water.

The present invention has an object to provide a method for operating a regenerative ion exchanger of an operation system in which a water collecting operation is interrupted and then the water collecting operation is restarted, which is an economical operation method of the regenerative ion exchanger, which does not require a special mechanism in the regenerative ion exchanger, is easy to handle, and does not take time.

Technical scheme for solving problems

The method for operating a regenerative ion exchange device having an ion exchange resin layer in a container according to the present invention comprises: a raw water introducing step of introducing raw water into the regenerative ion exchanger in an upflow manner; a water supply stopping step of interrupting supply of the raw water to the regenerative ion exchange device; the ion exchange resin layer is in a state of being pushed up by the water passing pressure of the raw water in the raw water passing step, and after the raw water passing step is finished, the forced water for pushing down the ion exchange resin layer pushed up in the raw water passing step as a whole and moving the ion exchange resin layer is passed in a downward flow manner.

As the forcing water, deionized water obtained from the regenerative ion exchange apparatus is preferably used.

The height h of the free space (Freeboard) part of the regenerative ion exchange device is preferably 10 to 200 mm.

The L V (linear Velocity, L initial Velocity) when the forced water is passed is preferably 20 to 150m/h, and the forced water is preferably passed for 10 to 60 seconds.

Effects of the invention

In a regenerative ion exchange device for collecting water by operating in an upward flow manner, when water collection is stopped in the middle of water collection or when water passage of raw water is stopped at the time of water collection completion, etc., forced water for pressing an ion exchange resin layer downward is caused to flow downward immediately after water passage is stopped. By passing the forced water in this manner, the ion exchange resin layer in the apparatus moves downward in the container without being disturbed, and the ion exchange resin can be maintained in a fixed bed. Therefore, even after the water is collected again (restarted), the same water quality as before the stop can be ensured, and the operation can be stably performed. Even when the ion exchange resin is regenerated with chemicals, the regeneration can be performed efficiently, and the amount of chemicals can be reduced.

Drawings

FIGS. 1a, 1b and 1c are explanatory diagrams of the method of the present invention.

Fig. 2a, 2b, and 2c are explanatory diagrams of a conventional example.

Fig. 3 is a sectional view of a single-column multi-bed regenerative ion exchange device.

Fig. 4 is a sectional view of a single-column multi-bed regenerative ion exchange device.

Fig. 5 is a sectional view of a single-column multi-bed regenerative ion exchange device.

Detailed Description

The present invention is described in more detail below with reference to fig. 1a to 1 c. In the regenerative ion exchanger in which the ion exchange resin 4 is accommodated between the

filters

2 and 3 in the container 1, as shown in fig. 1a, raw water is introduced into the apparatus in an upward flow to collect water. When the upward flow of the raw water is stopped, as shown in fig. 1b, immediately after the upward flow of the raw water is stopped, the forced water is caused to flow downward in the container 1, and the forced water moves downward integrally with the layer of the ion exchange resin 4 (in a fixed bed state) as a whole, and as shown in fig. 1c, the layer of the ion exchange resin 4 is maintained in a fixed bed state, and the forced water is brought into contact with the lower filter membrane 3. When the layer of the ion exchange resin 4 moves downward, the collapsed portion 4a as shown in fig. 2b is not formed in the layer of the ion exchange resin 4, and mixing of the ion exchange resin particles does not occur. Therefore, when the flow of raw water to the regenerative ion exchange device is resumed so as to flow upward, the quality of the post-treatment water is immediately improved after the resumption.

In the present invention, as shown in fig. 1c, after the layer of the ion exchange resin 4 has finished moving downward, the regeneration of the ion exchange resin may be performed, and if a sufficient ion exchange capacity remains in the ion exchange resin, the raw water may be fed again without performing the regeneration.

As shown in fig. 2a, when the height h of the free space portion F is too large, the ion exchange resin layer is likely to be disturbed. Since the precipitability of the ion exchange resin varies depending on the specific gravity, the height h of the free space portion F is preferably set in consideration of the specific gravity. The specific gravity of the anion exchange resin is usually 1.0 to 1.2, and the specific gravity of the cation exchange resin is usually 1.2 to 1.7. The height h of the free space is preferably 10 to 200mm, more preferably 10 to 100mm, and particularly preferably 10 to 50 mm. Since cation-exchange resins are heavier than anion-exchange resins and tend to precipitate, when the free space is collected too widely, mixing during precipitation becomes easy. Therefore, it is more preferable to reduce the height of the free space portion in the case of filling the cation exchange resin than in the case of filling the anion exchange resin.

When the height h of the free space portion is determined, the height of the ion exchange resin layer is more preferably considered. The height of the ion exchange resin layer is usually in the range of 500 to 2000mm, and the ratio H/H of the height H of the free space part to the height H of the ion exchange resin layer is preferably 1/50 to 1/2.5, more preferably 1/20 to 1/10.

When L V (linear Velocity, L initial Velocity) is too small when forced water is passed through the water so as to flow downward, the ion exchange resin layer cannot move integrally, and therefore, 20m/h or more is preferable, and if L V is too large, the ion exchange resin near the upper surface of the ion exchange resin layer is disturbed, and therefore, L V is preferably 150m/h or less, and L V is preferably 20 to 150m/h, and particularly preferably 30 to 60 m/h.

The downward flow of the urging water is preferably started immediately after the upward flow of the raw water is stopped, and more specifically, immediately after the upward flow of the raw water is stopped, particularly within 1 second or less. The duration of the water supply of the force application water is preferably about 10 to 60 seconds.

The regenerative ion exchange device may be any of a single-column multi-bed type, a multi-column single-bed type, a single-bed type, and the like. In the case of the single-column multi-bed type, an apparatus having a structure as shown in FIGS. 3 to 5 can be used.

Fig. 3 to 5 are longitudinal sectional views of a single-column double-bed regenerative ion exchanger, wherein fig. 3 shows water collection, fig. 4 shows regeneration, and fig. 5 shows forced water flow. In the regenerative ion exchanger 40, the upper chamber 20 in the column body 41 is filled with an Anion (Anion) exchange resin 21, and the lower chamber 30 is filled with a Cation (Cation) exchange resin 31, thereby forming a double bed in the column body 41.

The housing of the tower body 41 of the regenerative ion exchange device 40 is composed of a cylindrical portion 41a having a cylinder axis direction as a vertical direction, a mirror plate portion 41b at the top, and a mirror plate portion 41c at the bottom. The mirror plate portion 41b is curved upward in a convex shape, and the mirror plate portion 41c is curved downward in a convex shape.

The tower 41 is divided into an upper chamber 20 and a lower chamber 30 by a water-impermeable partition 42. In this embodiment, the spacer 42 is made of metal or synthetic resin which does not allow water to pass therethrough at all, and is bent in a convex shape downward in the same manner as the mirror plate portion 41 c. The peripheral edge of the separator 42 is joined to the inner peripheral surface of the cylindrical portion 41a in a watertight manner by welding or the like.

A first water collecting block 44 is disposed at an upper portion in the upper chamber 20, and an upper water supply and discharge pipe 43 is connected to the first water collecting block 44. A second water collecting block 46 is provided at a lower portion in the upper chamber 20, and a first communication pipe 45 is connected to the water collecting block 46. A third water collecting member 49 is provided in an upper portion of the lower chamber 30, and the second communication pipe 48 is connected to the water collecting member 49. The

communication pipes

45 and 48 are connected by a third communication pipe 51, and a valve 52 is provided in the communication pipe 51.

Valves

47 and 50 as supply and discharge means for the regenerative liquid are provided at the end portions of the

communication pipes

45 and 48. A fourth water collecting part 54 is provided at a lower portion of the lower chamber 30, and a lower supply and discharge pipe 53 is provided at the water collecting part 54.

The anion exchange resin 21 is filled in most of the upper chamber 20, and the granular inactive resin 22 is filled above the anion exchange resin 21. The first water collecting member 44 is embedded in the non-reactive resin 22.

A cation exchange resin 31 is filled in most of the lower chamber 30, and a granular inactive resin 32 is filled above the cation exchange resin 31. The third water collecting member 49 is embedded in the inert resin 32. As the inert resin, polyacrylonitrile-based resin or the like having a lower specific gravity than ion exchange resin or the like is used. The particle size of the inactive resin is preferably about the same as that of the ion exchange resin.

As the

water collecting members

44, 46, 49, and 54, a water collecting plate used in a conventional ion exchanger, a strainer provided with a plurality of slits in radially extending pipes, or the like can be used. For example, when the size of the ion exchange resin is about 0.4mm, a strainer having a slit width of about 0.2mm is preferably used as the strainer. The

water collecting members

44, 46, 49, 54 have shapes along the mirror plate portion 41b, the spacer 42, and the mirror plate portion 41c, and the dead space (dead space) along the mirror plate portion 41b, the spacer 42, and the mirror plate portion 41c is made small.

The flow of deionized water production (water collection) using this ion exchange apparatus is shown in fig. 3. In this case, the valve 52 is opened, the

valves

47 and 50 are closed, and raw water (water to be treated) is supplied from the lower supply/discharge pipe 53. The raw water is taken out as treated water (deionized water) by passing through a water collecting and distributing member 54, a cation exchange resin 31, an inactive resin 32, a water collecting and distributing member 49,

communication pipes

48, 52, 45, a water collecting and distributing member 46, an anion exchange resin 21, an inactive resin 22, a water collecting and distributing member 44, and an upper supply and discharge pipe 43 in this order.

When the raw water flows upward from the

water collecting members

54 and 46, the cation exchange resin 31 and the anion exchange resin 21 float upward and are pressed against the lower surfaces of the layers of the

inactive resins

32 and 22, respectively. When the water collection is stopped, as shown in fig. 5, immediately after the flow of raw water is stopped, the valve 52 is closed, the

valves

47 and 50 are opened, the forced water is caused to flow downward from the water collecting and distributing

members

49 and 44, the forced water is discharged from the water collecting and distributing

members

54 and 46, the layers (in a fixed bed state) of the cation exchange resin 31 and the anion exchange resin 21 are integrally moved downward, the cation exchange resin 31 is brought to the mirror plate portion 41c, and the anion exchange resin 21 is brought to the partition plate 42. Thereby, free spaces are formed between the cation exchange resin 31 and the inactive resin 32 and between the anion exchange resin 21 and the inactive resin 22, respectively.

When the cation exchange resin 31 and the anion exchange resin 21 move downward, no collapse portion as shown in fig. 2b is formed in each of the layers of the cation exchange resin 31 and the layers of the anion exchange resin 21. The valve 52 may be opened, the

valves

47 and 50 may be closed, the biasing water may be passed through the upper and lower chambers so as to flow downward from the water collecting and distributing member 44 and be discharged from the lower water supply and discharge pipe 53.

When regenerating the cation exchange resin 31 and the anion exchange resin 21, as shown in FIG. 4, the valve 52 is closed, the

valves

47 and 50 are opened, the alkaline solution such as NaOH is supplied from the upper supply/discharge pipe 43, and HCl and H are supplied from the third communication pipe 48₂SO₄And the like. The alkaline solution flows through the water collecting and distributing member 44, the inactive resin 22, the anion exchange resin 21, the water collecting and distributing member 46, the communication pipe 45, and the valve 47 in this order, and flows out as regeneration wastewater (alkaline), whereby the anion exchange resin 21 is regenerated. The acid solution flows in the order of the water collecting member 49, the inactive resin 32, the cation exchange resin 31, the water collecting member 54, and the lower water supply and discharge pipe 53, and flows out as regeneration wastewater (acid), thereby regenerating the cation exchange resin 31.

After completion of the regeneration, pure water is passed through the upper chamber 20 and the lower chamber 30, instead of the HCl solution and the NaOH solution of fig. 4, and after flushing the respective paths and the resin, the upper chamber and the lower chamber are separately washed with pure water in a downflow manner, and the washing drainage is discharged, if necessary, and then the pure water is circulated for a predetermined time between the upper chamber and the lower chamber, and then returned to the water collection step. In this regeneration, the anion exchange resin 21 and the cation exchange resin 31 are not mixed at all. The alkaline solution for regeneration flows into the lower chamber 30, and the acid solution is mixed into the upper chamber 20, so that reverse regeneration is completely prevented. The anion exchange resin 21 and the cation exchange resin 31 can be regenerated at the same time, and the regeneration time is remarkably shortened.

In this ion exchange apparatus, the inside of one column body 41 is partitioned into two chambers, an upper chamber and a lower chamber, by a partition plate 42, and the height of the column body is low and the installation space is small. The

pipes

45, 51, 48 for connecting the upper chamber 20 and the lower chamber 30 can be shortened.

In this ion exchanger,

water collecting members

54, 46, 49, and 54 are provided along the mirror plate portion 41b, the partition plate 42, and the mirror plate portion 41c, and local retention of water is prevented.

In this ion exchanger, the upper portions of the upper chamber 20 and the lower chamber 30 are filled with the

inactive resins

22 and 32 to prevent the flow of the anion exchange resin 21 and the cation exchange resin 31, and at the time of water collection and regeneration, the liquid is uniformly brought into contact with the anion exchange resin 21 and the cation exchange resin 31 to obtain deionized water having high water quality and sufficiently regenerate the same.

In fig. 3 to 5, the anion exchange resin is contained in the upper chamber 20 and the cation exchange resin is contained in the lower chamber 30, but the arrangement may be reversed. In fig. 3 to 5, the upper chamber 20 and the lower chamber 30 communicate with each other through the

pipes

45, 51, and 48, but the present invention is not limited thereto as long as the upper chamber and the lower chamber are wound around the outside of the tower body 41. In fig. 3 to 5, three

valves

47, 50, and 52 are used, but two three-way valves may be used to switch the flow paths.

The forcing water used for the downward flow of water may be the treated water of the regenerative ion exchange apparatus or may be any of the treated water of the subsequent stage, and it is preferable to use the treated water or the water having a purity corresponding to the treated water.

The downward flow of the forced water may be either one of the methods of simultaneously passing water through the front-stage tower and the rear-stage tower (parallel water passing) separately or passing water directly from the rear-stage tower to the front-stage tower in series, but it is preferable to pass water through the front-stage tower and the rear-stage tower separately in parallel.

Examples

[ example 1]

In the regenerative ion exchanger shown in FIG. 3, the single-column multi-bed regenerative ion exchanger was constructed by filling the upper stage of a vessel having an inner diameter of 600mm with an anion exchange resin so that the height became 1000mm, and filling the lower stage with a cation exchange resin so that the height became 500 mm. The height h of the free space portion was set to 200 mm.

Strong base anion exchange resin: dow MONOSPHERE 550A (OH) specific gravity 1.1

Strong acid cation exchange resin: dow MONOSPHERE 650C (H) specific gravity 1.4

Raw water having a specific resistance of 0.1 M.OMEGA.cm (conductivity 10. mu.S/cm) was caused to flow upward at 20M³Water is passed to the regenerative ion exchange apparatus (ion exchange resin column). When 3 hours passed from the start of the water flow, the water flow was stopped, and the forced water was immediately forced to flow downward by 10m³The water collection amount is the total amount of treated water up to the time point at which the specific resistance of the treated water becomes 18M Ω · cm or less, and is shown in table 1.

As shown in table 1, in example 1, the specific resistance of the treated water was 18.2M Ω · cm after 77 hours from the start of water supply, and 18.0M Ω · cm. after 84 hours, and the total collected water amount for 84 hours was 1440L.

Comparative example 1

The operation of the regenerative ion exchange device was performed in the same manner as in example 1, except that the forced water was not passed downward after the passage of the raw water was stopped. The change in specific resistance with time and the water collection amount of the treated water are shown in table 1.

As shown in Table 1, in comparative example 1, the specific resistance of the treated water was 18.2 M.OMEGA.cm after 28 hours from the start of water passage, but the total water collection amount was 570L since the specific resistance of the treated water was reduced to 15.5 M.OMEGA. cm. after 35 hours.

Comparative example 2

The regenerative ion exchange device was operated in the same manner as in example 1, except that the flow of raw water was not stopped but was continued. The change in specific resistance with time and the water collection amount of the treated water are shown in table 1.

In comparative example 2, the specific resistance of the treated water was 18.2 M.OMEGA.cm and 18.0 M.OMEGA. cm. in 84 hours and the total water collection amount in 84 hours was 1440L in 77 hours from the start of water introduction in the same manner as in example 1.

Comparative example 3

The regenerative ion exchange device was operated in the same manner as in example 1, except that the height h of the free space portion was set to 300 mm. The change in specific resistance with time and the water collection amount of the treated water are shown in table 1.

In comparative example 3, the specific resistance of the treated water was 18.2 M.OMEGA.cm from the start of water passage to 42 hours, but the total water collection amount was 680L because the specific resistance of the treated water decreased to 17.5 M.OMEGA. cm. after 49 hours.

[ Table 1]

As shown in table 1, according to example 1, even if the water supply of the raw water was repeatedly interrupted, the collected water amount was large. The water collection amount in example 1 was found to be sufficient to utilize the exchange capacity of the ion exchange resin, as in comparative example 2 in which the operation was continued.

The water collection amount of comparative example 3 was smaller than that of example 1. The water collection amount of comparative example 1 was further smaller than that of example.

As is clear from the above embodiments, according to the present invention, even if the water passage of the raw water is repeatedly stopped in the middle of water collection, the same amount of water collection as in the case of continuous water passage can be secured.

The present invention has been described in detail using the specific embodiments, but it is apparent to those skilled in the art that various modifications can be made without departing from the purpose and scope of the present invention.

The present application is based on Japanese patent application No. 2013-092659 filed on 25.4.2013, the entire contents of which are incorporated herein by reference.

Claims

1. A method for operating a regenerative ion exchange device having an ion exchange resin layer in a container, comprising:

a raw water feeding step of feeding raw water to the regenerative ion exchanger in an upward flow manner,

and a water supply stopping step of interrupting the supply of the raw water to the regenerative ion exchange device;

in the raw water passing process, the ion exchange resin layer is in a state of being pushed upwards by the water passing pressure of the raw water;

it is characterized in that the preparation method is characterized in that,

after the raw water passing step is completed, forced water for moving the ion exchange resin layer by pressing the ion exchange resin layer pushed up in the raw water passing step downward as a whole is passed in a downward flow manner.

2. The method of operating a regenerative ion exchange unit according to claim 1, wherein deionized water obtained from the regenerative ion exchange unit is used as the forced water, and the forced water starts to flow within 1 second after the raw water flow step is completed.

3. The method according to claim 1, wherein the height of the free space of the regenerative ion exchange device is 10 to 200 mm.

4. The method of operating a regenerative ion exchange unit according to claim 1, wherein L V is 20 to 150m/h when the forced water is passed therethrough.

5. The method of operating a regenerative ion exchange device according to any one of claims 1 to 4, wherein the forced water is passed through the regenerative ion exchange device for 10 to 60 seconds.