JPH0661467B2 - Separation and transfer method of ion exchange resin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for producing pure water and ultrapure water, and more particularly to a condensate desalination apparatus for condensate treatment in thermal power plants and nuclear power plants.

(Prior Art) A mixed resin layer of two kinds of ion exchange resins, particularly a strongly acidic cation exchange resin (hereinafter referred to as SAR) and a strongly basic anion exchange resin (hereinafter referred to as SBR) is pure water or ultrapure water. It is indispensable for polisher and thermal power of manufacturing equipment and condensate desalination equipment of nuclear power plants.

The water quality required for condensate treatment at a PWR nuclear power plant is the most severe:

Na (sodium ion) concentration 0.02 ppb or less Cl (chlorine ion) concentration 0.05 ppb 〃 The lower the concentration of these ions, the better.

The amount of leakage of these ions from the mixed resin layer is governed by the ratio of the salt-type resin in the mixed resin layer except for the inlet water quality condition and the operating condition (LV etc.) of the mixed resin layer.

That is, R-Cl (chlorine type anion resin), R-Na
The higher the proportion of (sodium-type cation resin) present, the more Na
^+, Cl ^- leakage increases. These R-Na, R-
The main reasons for producing Cl are as follows except for Na and Cl derived from raw water.

R-Na: The separation and transfer of SAR and SBR are incomplete, and SAR mixed in the SBR layer comes into contact with NaOH as a regenerant and is generated.

R-Cl: (1) Generated by impurities (NaCl) in regenerant NaOH.

(2) As with R-Na, the separation of SAR and SBR is incomplete and S
The SBR remaining in the AR layer is produced by contact with the regenerant HCl.

Various methods for reducing the production of R-Na have been studied, and Japanese Patent No. 1027750 is typically proposed.

The main cause (1) of R-Cl formation is that the problem is lessened by the improvement of the quality of NaOH. Regarding (2), in the conventional technology, separation and transfer are incomplete, and the SAR layer contains 1-2% of the total SBR.
Since some SBR remains and accumulates with each regeneration, in the equilibrium state, R-Cl in the mixed resin layer accounts for more than 20% of the total SBR.
The value is 30 to 30%.

The conventional separation transfer is performed as follows. That is, the fifth
As shown in the figure, LV 8 to 10 m / hr of backwash water is introduced from the lower part of the tower, sufficiently backwashed and separated, and after calming, sluising water is introduced from the lower part of the tower at about LV 25 m / hr to slightly flow the SAR layer 1. Pressurized water or pressurized air is introduced from the top of the tower to transfer the anion regenerating resin 2 to the anion regenerating tower.

Although the opening 4'of the resin transfer pipe 4 is located on the central axis of the tower in FIG. 5, it may be located on the wall of the tower, or in some cases "toi" is used. Further, the height of the opening 4'is usually set slightly below the resin separation interface d.

When such transfer is performed, the SBR shown by the shaded area in FIG.
It is unavoidable that 2'remains several mm to 20 mm.

The reason is that the closer the SBR is to the tower wall, the longer it takes to reach the opening of the transfer pipe, and the resin near the opening is transferred during that time, and the resin surface becomes flat due to the slushing water from the lower part of the tower, and the opening 4 ' This is because a certain distance 1 is generated between the SBR and the resin surface, as shown in FIG. 6, and the SBR is not sucked into the opening 4'and is not transferred.

This phenomenon occurs in the same manner even if the amount of slushing water is increased to increase the expansion rate of the SAR layer 1, or the height and shape of the opening 4'is changed, and complete separation and transfer of SBR is not achieved.

These residual SBR2 'come into contact with the regenerant HCl to produce R-Cl.

Although the method shown in FIG. 5 causes a considerable amount of SBR to remain, the method shown in FIGS. 7 and 8 has also been proposed, and the amount of SBR remaining is extremely small.

The method shown in FIG. 7 is the most conventional SBR
After transferring the residual SBR2 ', when transferring the residual SBR2', the valve 9 is opened with SAR1 to introduce the backwash water, and the valve 10 is opened with the backwash water discharged while draining the backwash water to develop the backwash water while in the fluidized state. A device 3 and 3'for blowing out pressured water in the circumferential direction, which causes a swirl flow in the water in the upper part of the tower, forms an opening 4'in the resin transfer pipe 4 slightly above the separation boundary surface e. The valves 11 and 11 'are opened through the flow path, and the SBR 2'is collected in the opening 4'to continuously transfer the SBR 2'by utilizing the flow collected in the tower by the swirling flow. In this method, unless the valve 12 of the resin transfer pipe 4 is opened to create a flow of water, the flow of SBR collecting on the central axis of the tower does not occur.

Even if the valve of the resin transfer pipe 4 is closed and the valve 10 of the water collecting device at the upper part of the tower is opened, the SBR will not collect on the central axis of the tower no matter how much the swirling flow occurs when the water is full.

The feature of this system is that the transfer of the residual SBR 2'is achieved in a short time.

However, the drawbacks of this method are as follows.

1) Since the flow rate of the backwash water from the lower part of the tower is as high as LV 5 to 10 m / hour, the backwash expansion rate of SAR1 is large, and strict control of this flow rate is required. Since the backwash expansion rate differs depending on the water temperature, it is necessary to precisely control the water temperature.

If the opening control of the valve 9 is not sufficient and the backwash expansion rate becomes too large than the set value, a large amount of SAR1 will be transferred, and if the backwash expansion rate is small, the transfer of SBR2 will be insufficient and there is a risk of remaining. is there.

Therefore, the resin balance of SAR and SBR will be improved.

Usually, there are 2 to 10 demineralization towers in the condensate demineralizer, and the collapse of the resin balance greatly affects the treatment performance of the desalination tower.

2) That is, in this method, when fully automated driving is performed, S
Since AR1 is used as a fluidized bed, there is a great uncertain factor in the quantification of SAR-1 and its reliability is lacking. For this reason, manned operation is required during check-up due to the backwash expansion rate check.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problem (2), further reduces the SBR remaining in the SAR during separation and transfer, and achieves a highly reliable quantitative determination of SAR1. It provides an excellent method of fully automatic unmanned driving.

(Means for Solving the Problems) The inventors of the present invention have achieved the present invention as a result of earnest research using a column having a large diameter on a practical scale in order to solve the problems of the conventional separation and transfer method. .

According to the present invention, most of SBR2 having a small specific gravity is transferred, and then SBR2 'remaining on the SAR layer 1 is transferred. 1) As shown in FIG. Positions near or above the surface layer of the ion-exchange resin having a small specific gravity), for example, swirling water introduction pipes 3, 3 '
Of the swirling water while introducing the backwash water Q ₁ at an LV of ₈ to 15 m / hour in this state by opening the exhaust valve 8 at the upper part of the tower to 6 ′ and opening the exhaust valve 8 at the top of the tower. Further, the swirling flow water Q ₂ is introduced at an LV of ₂ to 5 m / hour, and if a sufficient swirling flow occurs after a few minutes, the introduction of Q ₁ and Q ₂ is stopped and the resin layer is calmed.

2) As shown in FIG. 3, the water level 6 ″ in the tower after sedation is several tens of centimeters higher than the water level 6 ′ shown in FIG.

During the settling time, that is, the resin layer surface position b during backwash development
1-2 until the position a of the fixed layer surface layer after sedation
There is a difference in specific gravity between the swirling flow and SAR and SBR between minutes,
The SAR and SBR are well separated due to the different settling velocities, and the residual SBR near the center axis of the column as shown in Fig. 3.
2'is concentrated.

3) Then, the SBR 2'concentrated in the fixed bed state from the opening 4'of the resin transfer pipe 4 provided on the central axis of the tower and slightly below the separation interface c in the fixed bed, and the addition introduced from the upper part of the tower. Transfer using compressed air or pressurized water only. After the transfer, the concentrated portion of the SBR 2'is transferred as shown in FIG. 4, and a dent occurs in that portion.

When such a transfer is performed, the SAR1 is not transferred excessively, and on the contrary, the SAR1 tends to remain above the set value. Then, in order to ensure that the amount of SAR1 is kept at the set value, the transfer water Q ₃ is transferred from the transfer slusing pipe 7 provided slightly below the separation interface shown in FIG.
It is introduced at a rate of 5 m / hour, and pressurized water Q ₄ or pressurized air is introduced from the upper part of the tower and transferred through the transfer port 4 ′.

As described above, according to the present invention, the SB remaining in the [backwash water + swirl flow] is
R2 'is collected on the central axis of the tower to form a fixed bed, which is transferred from the transfer port 4'provided on the central axis of the tower, and then the excess SAR is transferred while the majority of the SAR remains in the fixed bed, and the transfer sluising pipe 7 is used. It is carried out by using slewing water from S.A.R., and reliable transfer of residual SBR 2'and quantification of SAR are ensured.

The SAR remaining after the transfer is the sum of the fixed layer below the transfer sluising pipe 7 and the upper part of the transfer sluising pipe 7 that receives the flow of the transfer sluising water Q ₃ .

In FIG. 1, f is the position of the SAR surface layer after the transfer, but the part of the whole SAR which is the fixed layer is the whole, and the separation surface c before the transfer which receives the flow and the sluising pipe 7 for the transfer.
By shortening the distance of 100 to 250 mm, Q
_{Even if 3} fluctuates considerably, f fluctuates very little.

The structure of the sluising pipe for transfer may be similar to that of the tower upper water collecting device 17 or the lower tower water collecting device 18 as long as the water is uniformly distributed over the entire cross section of the tower.

Next, the present invention will be described in detail with reference to FIG. After transferring the resin from the desalting tower (not shown) to the separation tower 22,
Valves 9 and 10 are opened and backwash water is introduced to sufficiently perform backwash separation.

After the valves 9 and 10 are closed and the resin layer has settled, the valve 16 is opened,
While introducing sluizing water for transfer at an LV of about 2.5 m / hour, the valves 13 and 12 are opened and pressurized water Q ₂ is introduced to transfer most of the SBR to the anion regeneration tower (not shown).

Then, the transfer method of the present invention is performed.

The valves 12, 13, 16 are closed, the valve 19 is opened, pressurized air is introduced, the valve 21 of the freeboard drain pipe 20 is opened, and water is blown out in a circumferential direction from the full water level to a swirling flow. Lower to the position of the Breeboard drain tube 20 located at the bottom of the tubes 3,3 ".

Then, the valve 21 is closed, the valves 8 and 10 are opened to open the inside of the tower to the atmosphere, the valve 9 is opened, and the backwash water Q ₁ is LV ₅ to 10 m.
/ To the valve 11, 11 'and open while introducing when Q ₂ the LV2
It is introduced at a rate of -5 m / hour for 1 to 3 minutes to generate a swirling flow.

It is also effective to introduce Q _{2 a} few minutes after the introduction of Q ₁ .

After 1 to 3 minutes, the valves 8, 9, 10, 11, 11 'are closed and the valve is settled for 1 to 3 minutes.

At this time, the water level only rises from the position of the freeboard drain pipe 20 to the water level 6 in FIG. During the sedation period, residual S due to the difference in specific gravity between the swirling flow and SAR and SBR
BR2 'gathers on the central axis of the tower as shown in FIG. Third
The spread of the residual SBR 2'shown is 150-600φ, which is governed by the amount of residual SBR 2'and Q ₂ .

Tower central axis, i.e. by introducing a pressurized water Q ₄ or the valve 19 to the 'AtsumariTsuta residual SBR2 near' the opening 4 of the resin transfer pipe 4 and the valve 13 opened to open and to pressurized air, the fixed layer of the valve 12 is opened The remaining residual SBR 2'is transferred to the anion regeneration tower.

At this time, the amount of SBR 2 ′ transferred is difficult to transfer due to the above-mentioned spread of 150 to 600 φ. Therefore, it is preferable to repeat the reverse regeneration degree + swirl flow and transfer.

The steps to be repeated are summarized as follows.

Open valve Step (1) Drain 19 21 Step (2) Backwash 8 9 10 2 to 3 minutes Step (3) Backwash + 8 9 10 11 11 11 ′ Swirl flow 1 to 3 minutes Step (4) Silence Close all Step (5) Transfer 12 13 About 3 times is sufficient for this repetition. Residual SBR2 '
This is because the residual SBR 2'collects near the opening 4'as the amount of P is smaller.

Further, extra SAR is transferred in order to maintain the quantitativeness of SAR.

After closing the valves 12 and 13, the valve 15 is opened to introduce the transfer slushing water Q ₃ at an LV of ₄ to 5 m / hour, and the valves 12 and 1 are introduced.
Open 3 and introduce pressurized water Q ₄ to transfer excess SAR.

At this time, Q ₃ is preferably set to be larger than the value at the time of transferring most of the SAR when the valve 16 is opened.

By performing the above-described operation, the residual SBR 2'can be reliably transferred, and the quantification of the SAR is stably maintained, so that the fully automatic unmanned operation can be performed.

Next, examples of the present invention will be described.

Comparative Example 1 Dowex HGR-W (registered trademark) 4500 as SAR and D as SBR in a separation tower having an inner diameter of 1800φ and a height of 5000 mm.
It was filled with a mixed resin of owex TG 550A® 2000. After backwashing and separation at LV 10 m / hr for 30 minutes, after sedation, sluzing water was introduced at LV 2.5 m / hr from the lower part of the tower, and simultaneously pressurized water was introduced at LV 4 m / h from the upper part of the tower.

The opening of the resin transfer pipe was one at the central axis of the tower, and the one having a diameter of 75 was used.

The position was 100 mm below the resin boundary surface.

The SBR remaining after the transfer was 0.6 to 1.0% of the total SBR.

The investigation of residual SBR was conducted as follows.

After transfer, after backwashing for 40 minutes at LV of 12 m / hour, all the SBR collected on the surface layer was scraped off and the volume was measured.

Example 1 The same tower and resin as in Comparative Example 1 were used.

The process is as follows.

[1] transferring Q Most SBR _3: LV2.5m / h Q _4: LV4 m / h [2] repeating step process (1) Drain valve 21 opens pressurizing pressure air LV10m
/ Hour Step (2) Backwash Q ₁ : LV12m / hour 3 minutes Step (3) Backwash + swirling flow Step (4) Sedation 3 minutes Step (5) Transfer Q ₄ = LV 4 m / hour 5 minutes The above steps were repeated 3 times.

[3] Transfer of extra SAR Q ₃ = LV 5 m / hour 5 minutes Q ₄ = LV 4 m / hour Then, the residual SBR was measured.
It was 02 to 0.03%.

It was measured by changing the Q ₃ when extra SAR transported in the same conditions tolerance and Example 1 Q ₃ when transferring SAR of Example 2 extra.

At this time, the position variation f in FIG. 1 was as small as 5 mm or less.

[Brief description of drawings]

FIG. 1 is a drawing for explaining a method of separating and transferring an ion exchange resin of the present invention, FIG. 2 is a drawing showing a water level in a tower when introducing water for swirling flow, and FIG. 3 is a water level after settling of swirling flow. And a drawing showing a concentrated state of the anion exchange resin, FIG. 4 is a drawing showing a state after the residual anion exchange resin is transferred, and FIG. 5 is a drawing for explaining a conventional separation and transfer method of the ion exchange resin, FIG. 6 is a drawing showing the anion exchange resin layer remaining on the cation exchange resin layer after transfer of the anion exchange resin,
FIG. 7 is a drawing for showing a conventional method for separating and transferring an ion exchange resin, which is different from FIG. 5, and FIG. 8 is a drawing showing a flow of water in the vicinity of the resin interface. 1 ... Cation exchange resin layer, 2 ... Anion exchange resin layer, 2 '... Residual anion exchange resin layer, 3, 3' ... Pressure water blowing device, 4 ... Resin transfer pipe, 4 '... Opening, 6 '
…… Water level at the start of swirling flow, 7 …… Transmission sluising water inlet pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuyuki Sasaki 1-6-27 Konan, Minato-ku, Tokyo Ebara Infilco Co., Ltd. Inside the EBARA CORPORATION

Claims (4)

[Claims] 1. An ion exchange column filled with two types of ion exchange resins having different specific gravities. The ion exchange resin is separated into two layers by backwashing, and pressurized air or pressurized water is introduced from the top of the column. And transferring most of the ion-exchange resin having a small specific gravity, and separating and transferring the ion-exchange resin having a small specific gravity remaining on the ion-exchange resin layer having a large specific gravity after the transfer, a) water to an appropriate position And, after opening the upper part of the tower to the atmosphere, while introducing backwash water from the lower part of the tower, pressure water is blown out in a circumferential direction from a position located above the surface layer of the ion exchange resin having a small specific gravity, Step of giving a swirling flow to the water in the tower b) After a sufficient swirling flow is obtained, the introduction of the backwash water and the blowout of the pressure water in the circumferential direction are stopped to calm the resin layer, and the backwash is performed. The developing resin layer is calmed down and becomes a fixed layer The ion-exchange resin with a small specific gravity that has remained in the backwash until it is collected near the center axis of the tower by the separating action and swirling action due to the difference in specific gravity c) Ion exchange with a small specific gravity collected near the center axis of the tower A method for separating and transferring an ion exchange resin, which comprises the step of transferring only resin by introducing pressurized air or pressurized water from the upper part of the tower through a resin transfer pipe. 2. The method according to claim 1, which comprises repeating steps a), b) and c) in the method for separating and transferring the ion exchange resin. 3. The method according to claim 1, wherein the position of the opening of the resin transfer pipe is set slightly below the separation boundary surface in the fixed layer. 4. When storing most of the ion exchange resin having a small specific gravity, slewing water is introduced from an intermediate sluising pipe provided slightly below the opening of the resin transfer pipe. The method according to item 2 or 3.