JPH0768254A - Pure water producing apparatus and its regeneration - Google Patents

Abstract

PURPOSE:To reduce the formation of a precipitate at the time of the regeneration of the mixed bed type ion exchange tower of a pure water producing apparatus using raw water high in the concn. of a relatively hard component and an alkalinity component or raw water high in the content of both components. CONSTITUTION:After the hardness component in raw water is removed in a weak acidic cation exchange tower, decarbonization is performed in a decarbonization tower 2 and decarbonated water from which carbon dioxide is removed is treated in a mixed bed type ion exchange tower 4 packed with strong acidic and strong basic ion exchange resins to obtain pure water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing pure water by an ion exchange method and a method for regenerating the same. In particular, the present invention relates to a pure water production apparatus suitable for producing pure water using raw water having a relatively high concentration or content of hardness component and alkalinity component, and a method for regenerating the same.

[0002]

2. Description of the Related Art A conventional mixed bed type ion exchange column in which a strongly acidic cation exchange resin (hereinafter referred to as SCR) and a strongly basic anion exchange resin (hereinafter referred to as SAR) are packed in the same column is pure. The regeneration process and the water passing process in the case of producing water will be described with reference to FIG.

Conventionally, the structure of a mixed bed type ion exchange column (hereinafter referred to as an MB column) is as shown in FIG. 2, and after the pure water is produced by passing water for a certain period of time, the resin is Enter the regeneration process of the ion exchange capacity of.

In the regeneration step, first, raw water is supplied from the pipe 52 at the bottom of the MB tower 50, and while the resin layer is fluidized, a backwash operation is carried out in which the water flows upward in the tower and is discharged from the pipe 54 at the top of the tower. To do. By this operation, S with a low specific gravity is
The AR 56 is separated such that the SCR 58 having a high specific gravity is located in the lower part. Next, after both resins have settled into two layers, while supplying the pressed water from the pipe 60 at the lower part of the tower, the alkaline regenerant is supplied from the pipe 62 to regenerate the SAR 56, and the recycled waste liquid is the recycled waste liquid outlet provided on the separation surface. It is discharged from the pipe 66 via the collector 64. After that, the regeneration of the upper SAR 56 is completed by performing the extrusion cleaning of the regenerant on the same line. Next, while supplying the pressed water from the pipe 62, the acid regenerant is supplied from the pipe 60 at the lower part of the tower to supply SCR5.
8 is regenerated, and the regenerated waste liquid is discharged from the pipe 66 via the regenerated waste liquid outlet collector 64 provided on the separation surface.
After that, the regeneration of the lower SCR 58 is completed by extruding and washing the regenerant on the same line. After that, in order to remove a trace amount of acid, alkali and impurities remaining in the tower, the washing water is supplied from the pipe 68 at the upper part of the tower and the washing water is also supplied from the pipe 52 at the lower part of the tower to separate these. It is discharged from the pipe 66 via the collector 64 provided in the. Finally, the water in the tower is 20
It is pulled out from the pipe 70 to be about 30 cm, and air is supplied from the pipe 72 at the lower part of the tower to supply SCR58 and SAR in the tower.
Mix well with 56. After that, the raw water is supplied from the upper pipe 68, the inside of the tower is filled with air from the upper pipe 74 while the tower is filled with water, and then the raw water is supplied from the pipe 68 and the cleaning water is blown from the pipe 70. Playback is complete. The water passing step (pure water manufacturing step) is performed by supplying raw water to the pipe 68 in the upper part of the tower, and pure water is obtained from the pipe 78 via the water quality meter 76 in the lower part of the tower.

The purity of pure water is monitored by a water quality meter 76. When the purity does not satisfy a specified value, the pure water is blown from a pipe 70 and is not fed to a pure water line pipe 78. The above is the regeneration process and the water passage process of the MB tower 50, but this device has the following problems.

Calcium ions and magnesium ions in the raw water are adsorbed in the SCR 58, and silica and carbonic acid in the raw water are adsorbed in the SAR 56. When these resins come into contact with a caustic soda solution which is an alkali regenerating agent during regeneration, various precipitates of calcium hydroxide, magnesium hydroxide, calcium silicate, magnesium silicate, calcium carbonate, magnesium carbonate and the like are formed. To avoid this phenomenon, it is necessary to improve the separation of SCR58 and SAR56 when the backwash is sedated. However, in reality, the collector 64 provided at the outlet of the recycled waste liquid is used.
Separation of both resins in the vicinity is not always perfect, and it is general that SCR58 and SAR56 are partially mixed with each other. Therefore, contact between the alkaline regenerant (usually caustic soda solution) and SCR58 cannot be completely avoided, and therefore the above-mentioned precipitation is unavoidable.

[0007] Further, since the raw water is generally used as the reclaimed water such as the washing water and the extruded water, when the raw water has a high calcium concentration or magnesium concentration, in the regeneration process of SAR56, the alkali regenerant or the SAR after regeneration is used. There may be a problem that calcium, magnesium, carbonate, silica and the like in the raw water react with each other to partially form the various precipitates as described above.

These precipitates produced in the regeneration step are contained in the raw water in a large amount of calcium, magnesium, carbonate, silica and the like, and in the case where the absolute amount is not so large, the content ratio of the hardness component is large. When the amount is large, the amount of precipitates increases, which is a problem. Usually, it is unavoidable that a small amount of these precipitates are generated in the regeneration process, and the generated precipitate is finely divided in the air mixing process performed at the end stage of the regeneration process, and the activated resin after regeneration is used. It is solved by re-adsorbing to. However, if the amount of sediment increases, the quality of water may deteriorate after regeneration and pure water cannot be sampled, or the amount of water collected per cycle may decrease and the planned value may not be satisfied. For the above reasons, M
The raw water quality that can be supplied to the B tower 50 is 70 mg CaCO ₃ for both hardness components such as calcium and magnesium and carbonate.
It is generally said that the silica value is not more than 1/1 and the silica value is not more than ₃₀ mgCaCO ₃ / l.

It is generally said that the hardness component constitutes 50% or less of all cation components, and the carbonate ion component constitutes 50% or less of all anions.

Conventionally, when the water quality value exceeds the above, MB
K column filled with SCR, decarbonation column, S without column system
A so-called two-bed, three-column type deionized water producing device using an A tower filled with AR, or a method of producing deionized water by installing a mixed bed polisher (hereinafter referred to as MBP) at the subsequent stage has been adopted.

In the above-mentioned two-bed, three-tower pure water producing apparatus, the K tower,
Since the regenerant is separately supplied to both towers A and the tower K treated water or pure water is used for regeneration, various precipitates are not generated during the regeneration. However, in the two-bed, three-tower type pure water production system, high-purity water cannot always be obtained as in the mixed bed type pure water production system, and therefore MBP is often installed in the latter stage.

In this case, since the hardness component, carbonate, and silica which cause the precipitate are removed in the two-bed, three-column type deionized water producing apparatus in the previous stage, the precipitate is not generated when the MBP is regenerated. is there.

However, this method has a drawback that the equipment cost is high. Further, as another method for dealing with the MB tower alone, there may be a method of using pure water in the regeneration step. However, this method is also not very effective because a precipitate is generated when the alkali regenerant comes into contact with the components adsorbed on SCR and SAR.

[0014]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The inventor of the present invention is aware that when the amount of hardness components, carbonates, silica, etc. present in raw water and their composition ratios exceed a certain value as described above, during the MB tower regeneration process. In addition, as a result of diligent studies to solve the problems that various precipitates occur, the deterioration of purity, and the inability to secure the amount of water collected, as a result, among these components in the raw water, the hardness component and the carbonate are preliminarily separated by different means. After removing some or most of it, M
It was conceived that, when supplied to the B tower, precipitation formation in the regeneration step could be effectively suppressed, and the present invention was completed. The purpose of the present invention is to provide a relatively high concentration of hardness component and alkalinity component. Even when raw water or raw water having a high content rate of these components is used, there is little precipitate formation during regeneration of the MB tower, and the pure water production apparatus has a rapid rise in the purity of pure water after regeneration, and It is to provide a reproduction method. Still another object of the present invention is to provide a regeneration method that does not extend the regeneration time even if another means is added to the conventional MB tower.

[0015]

Means for Solving the Problems The present invention which achieves the above object, comprises a cation exchange column filled with a weakly acidic cation exchange resin, a decarboxylation apparatus, a decarbonation water tank, and a strongly acidic cation exchange resin. It has a mixed bed type ion exchange tower packed with a strongly basic anion exchange resin in the same tower, and the raw water is used as a cation exchange tower, a decarboxylation device, a decarbonation water tank, and a mixed bed type ion exchange tower. An apparatus for producing pure water, characterized in that pure water is taken out from a mixed bed type ion exchange tower by sequentially passing water.

According to the present invention, in the method for regenerating the pure water producing apparatus, an acid regenerant is passed through the strong acid cation exchange resin in the mixed bed type ion exchange column to regenerate the strong acid cation exchange resin. At the same time, the acidic regeneration waste liquid generated by the above-mentioned replenishment is sent to a cation exchange tower to regenerate the weakly acidic cation exchange resin in the cation exchange tower.

Furthermore, the present invention is the method of regenerating the pure water producing apparatus, wherein the strong basic anion exchange resin in the mixed bed type ion exchange column is first regenerated, and then the strong acid cation exchange resin is regenerated. The acidic regeneration waste liquid generated by the regeneration of the strongly acidic cation exchange resin is sent to the cation exchange column to regenerate the weakly acidic cation exchange resin, and while the strongly basic anion exchange resin is regenerated, the raw water Is passed through a cation exchange tower, and the treated water is used in the step of regenerating the strongly basic anion exchange resin.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the equipment configuration of the pure water producing apparatus according to the present invention. The apparatus of the present invention is a cation exchange tower 1 (hereinafter K
W tower), decarbonation tower 2 (hereinafter D
It is composed of a tower), a decarbonated water tank 3 (hereinafter referred to as DWT), and an MB tower 4. Each constituent device and its processing function will be described below. Inside the KW Tower 1,
H type weakly acidic cation exchange resin 5 (hereinafter referred to as WCR)
Is filled. When raw water is supplied to the KW tower 1 from the pipe 18, the hardness component corresponding to the alkalinity component (HCO ₃ ⁻ ) in the raw water is adsorbed and removed by the WCR 5, and most of the alkalinity component is changed to carbonic acid. The inside of the D tower 2 is filled with a decarboxylation filler 6 such as Raschig ring or terraret packing. When the treated water of the KW tower 1 is supplied to the D tower 2 from the upper pipe 19 and the air is supplied from the lower pipe 23, the supply water and the air are supplied on the surface of the decarboxylation filler 6 inside the D tower 2. Come into countercurrent contact, whereby the carbonic acid dissolved in the feed water moves into the air and is discharged from the pipe 25 to the outside of the system. As the decarbonation device, in addition to such a decarbonation tower, a known device such as a vacuum degassing tower, a heating degassing tower, or a membrane degassing apparatus using a degassing membrane may be used. it can. The treated water from which the carbonic acid has been removed (decarbonated water) flows into the DWT 3 provided at the bottom of the D tower. The amount of residual carbonic acid in this decarbonated water is generally about 5 to 10 mg · CaCo ₃ / l. The obtained decarbonated water is then supplied to the MB tower 4, where the impurity ions are removed to become pure water, which is taken out from the pure water outlet pipe 21. When pure water is sampled as described above to reach the prescribed amount, the KW tower 1 and MB
Regenerate tower 4.

Next, a method of regenerating the KW tower 1 and the MB tower 4 will be described. At the time of regeneration, the regeneration of the MB tower 4 is started.

Regeneration of the MB tower 4 begins with a backwash process. That is, the backwash water is supplied into the MB tower 4 from the pipe 16 at the bottom of the MB tower 4, and the SC is almost uniformly mixed in the MB tower 4.
R and SAR are in a fluid state. Since SCR and SAR have different specific gravities, they are separated from each other by the above operation. The backwash water is discharged from the upper pipe 17. After that, by stopping the inflow of backwash water and allowing the resin to settle, SCR
8 and SAR 7 settle in the MB tower 4 while maintaining a separated state.

Next, the SAR7 regeneration process is performed.

The alkali regenerant is supplied from the pipe 10 and the pressed water is supplied from the pipe 16 at the lower part of the tower to collect the generated regeneration waste liquid in the regeneration waste liquid outlet collector 9 and discharge it from the pipe 12. Known alkali regenerants can be used. Then, decarbonated water is supplied in the same line instead of the alkali regenerant, and the regenerant filling SAR7 is extruded. After that, at the same time as supplying water from the pipe 16,
The regeneration of SAR7 is completed by cleaning the SAR7 which is supplied with decarbonated water from the pipe 20 and discharged from the pipe 12. It should be noted that raw water is continuously passed through the KW tower until the regeneration process of SAR7 is completed. See also SAR7
Although decarbonated water was used as the reclaimed water in the above description, in some cases, the KW tower treated water may be used directly. Next, SCR 8 in MB tower 4 and KW tower 1
WCR5 regeneration process is performed. That is, first, the supply of raw water supplied to the KW tower 1 is stopped and the production of decarbonated water is interrupted. Next, the acid regenerant is supplied from the lower pipe 11 of the MB tower 4 and the pressurizing water is supplied from the pipe 10, and the acid regeneration waste liquid generated thereby is recycled waste liquid outlet collector 9
To collect water. The collected acidic regeneration waste liquid is guided to the regenerant inlet pipe 28 of the KW tower 1 via the pipe 13 and brought into contact with the WCR 5 in the KW tower 1, thereby regenerating the WCR 5 and then discharged from the lower pipe 14. Let Then, the extruding process of SCR8 and WCR5 is performed by switching to the decarbonated water in the decarbonated water tank 3 instead of the acid regenerant and performing the same operation, and then the washing process of the MB tower 4 and the KW tower 1 respectively. Implement independently.

The washing of the MB tower 4 is performed by supplying decarbonated water from the upper pipe 20 and the lower pipe 16 and discharging it from the pipe 12 through the regeneration waste liquid outlet collector 9.

The washing of the KW tower 1 is performed by supplying raw water from the pipe 18 and discharging it from the pipe 14. This completes the reproduction of SCR8 and WCR5.

As the acid regenerant, a known concentration and amount of a chemical used for regenerating a strongly acidic cation exchange resin can be used as it is.

Since the production of decarbonated water is suspended during this step as described above, the decarbonated water used in this step is the decarbonated water stored in the decarbonated water tank 3.

Next, the steps from the mixing step of the SCR 8 and the SAR 7 in the MB tower 4 to the full water blowing step and the backwashing step of the KW tower 1 are carried out by a conventional method. In addition, K
The backwashing process of the W tower 1 may use raw water or decarbonated water.

The backwashing step of the KW tower 1 may be carried out at the very beginning of the regenerating step simultaneously with the backwashing of the MB tower 4.

It should be noted that waste acid is not used for the regeneration of the KW tower 1,
When using a new acid regenerant, add KW
Supply from the pipe 29 of the tower 1.

Since the WCR 5 packed in the KW tower 1 has high regeneration efficiency, it can be regenerated by using the acidic regeneration waste liquid of the strongly acidic cation exchange resin packed in the MB tower 4 as described above.

[0032]

The present invention will be described in more detail with reference to the following examples.

In the case of producing pure water according to the present invention, KW
As described above, the effect is obtained when the hardness component, carbonate, etc., of the raw water supplied to the tower 1 are relatively large, or when the composition ratio is large.

The raw water quality used in the examples of the present invention is shown in Table 1.
Shown in.

[0035]

[Table 1] The apparatus having the configuration shown in FIG. 1 was used. Each of the components used will be described. The KW tower 1 has an inner diameter of 350 mm and a height of 16
It had a cylindrical shape of 00 mm and was filled with 75 l of Amberlite IRC-76 (trade name) as WCR5.

A cylindrical D tower 2 having an inner diameter of 300 mm and a height of 1600 mm was filled with a filler 6 (Raschig ring) having an outer diameter of 59 mm and a height of 19 mm to a height of 1200 mm. Air from pipe 23 of 100
Supplied in Nm ³ / H. Inner diameter 450 mm, height 3400
Amberlite IR-124 (trade name) as an SCR 8 and an Amberlite IRA-410 (trade name) as a SAR 7 in a cylindrical MB tower 4 mm of 80 l and 190 l, respectively.
Filled.

The regeneration process will be described below. First M
The backwashing process of the B tower 4 will be described.

1 backwash water is supplied from the pipe 16 at the bottom of the MB tower 4.
Supply SCR and SAR at a flow rate of 500 l / H for 15 minutes
And the backwash water was discharged from the upper pipe 17. After that, when the flow of backwash water was stopped and the ion exchange resin was allowed to settle, the precipitation of SCR8 and SAR7 and the separation of both resins were completed. In this state, the separation was good, but a mixed portion of SCR8 and SAR7 was present over the boundary surface between the two resins for about 30 mm. Next, the reproducing process of SAR7 will be described.

First, 720 l of a 4% (weight%, the same applies hereinafter) caustic soda aqueous solution was introduced from the pipe 10 to 1000 l / H.
And at the same time, decarbonated water as feed water was supplied at a flow rate of 360 l / H from the pipe 16 at the bottom of the tower to collect the regeneration waste liquid outlet collector 9 and discharge the alkali regeneration waste liquid from the pipe 12. Then, decarbonated water was supplied instead of the 4% caustic soda aqueous solution at the same route and at the same flow rate for 12 minutes to carry out the chemical solution extrusion step. Further piping 20 at the top of the tower
To 2300 l / H, piping 16 to 1500 at the bottom of the tower
Decarbonated water was supplied as washing water at a flow rate of 1 / H for 5 minutes at the same time to collect the liquid in the collector 9 and discharge it from the pipe 12. Up to this point, raw water was passed through the KW tower to continue producing decarbonated water.

Next, the SCR 8 of the MB tower 4 and the WC of the KW tower 1
The R5 regeneration process will be described.

First, 140 l of 5% hydrochloric acid was supplied from the lower pipe 11 of the MB tower 4 at a flow rate of 360 l / H, and at the same time, decarbonated water as feed water was supplied at a flow rate of 1000 l / H. The acidic regeneration waste liquid is taken out from the regeneration waste liquid outlet collector 9, and is passed through the pipe 13 to the KW tower 1
Was introduced into the KW tower 1 and was discharged from the lower pipe 14. After that, 5% HCl was switched to decarbonated water, and a chemical solution extrusion step was performed for 15 minutes at the same route and at the same flow rate.

From the pipe 20 at the upper part of the tower, 2300 l /
H, decarbonated water was simultaneously supplied as washing water for 5 minutes from the pipe 16 at the bottom of the tower at a flow rate of 1500 l / H, and the collected liquid was collected in the collector 9 and discharged from the pipe 12.

At this time, the KW tower 1 is washed by supplying raw water from the pipe 18 at a flow rate of 4 m ³ / H for 5 minutes and discharging it from the lower pipe 14, independently of the washing process of the SCR 8 of the MB tower 4. Carried out.

In the regeneration step, the S of the MB tower 4 is
The decarbonated water stored in the decarbonated water tank 3 is used only for the CR8 passage, extrusion, and washing steps, and the previous steps, that is, backwashing, SAR7 passage, extrusion, and washing steps are as described above. While producing decarbonated water in the KW tower 1 and the D tower 2, this was supplied as regeneration water to the MB tower 4 via the decarbonated water tank 3.

Next, the steps from the mixing step of the SCR 8 and the SAR 7 of the MB tower 4 to the full water blowing step, and the backwashing step of the KW tower 1 will be described.

The process of draining water from the pipe 15 at the bottom of the MB tower 4
Then, when draining water from the tower, air is blown from the upper pipe 24.
The water in the tower was drained almost completely in 20 minutes while being put. Next
Backwash water from the pipe 11 at the bottom of the tower as a mixing preparation step.
At a flow rate of 1500 l / H, a height of 200 mm above the resin surface
It was supplied until the water level rose. This takes about 6 minutes
It was Subsequently, compression is performed from the pipe 22 at the bottom of the tower as a mixing process.
Air (1.9kg / cm ² ) 18 Nm³ At a flow rate of / H
It was supplied for 5 minutes and exhausted from the upper air vent tube 24. This
In the step of SCR8 and SAR7 were mixed well. End of mixing
After completion, decarbonate water 7m from the upper pipe 20³ At a flow rate of / H
A process for discharging the water in the tower from the lower pipe 15 while supplying it.
The process was repeated until the inside of the tower was filled with water. This full water bro
-The time required for the process was 7 minutes. Upper pipe 2 after full water
Decarbonated water is supplied from 0, and the lower pipe 15 to 3000
Blow cleaning was performed by discharging at a flow rate of 1 / H. Water quality
The indicated value of purity (electrical conductivity) of 30 is the full water blow
After about 2 minutes, it shows 1μS / cm (25 ℃) and blows with full water.
At the end, it showed 0.5 μS / cm (25 ° C.). next
The purity after 5 minutes of blow cleaning is 0.2 μS / cm (25
° C). Decarbonated water is used in the draining process of the MB tower 4.
Since it is not used, the backwashing process of the KW tower 1 is performed during this process.
gave.

In the backwashing method, raw water was supplied from the lower pipe 26 of the KW tower 1 at a flow rate of 1000 l / H for 15 minutes, and the backwash water was discharged from the upper pipe 27.

Then, the regeneration of the KW tower 1 was completed by resting the WCR for 5 minutes. Thus, by performing the regeneration of the KW tower 1 during the regeneration process of the MB tower 4, the regeneration required time of the method of the present invention can be carried out at the same time as the regeneration required time of the conventional MB tower 4. That is, no extra time is required other than the regeneration time of the MB tower 4. Next, the water passing step was carried out.

Raw water is supplied to KW tower 1, D tower 2, decarbonated water tank 3,
Water was passed through the MB tower 4 in this order at a flow rate of 4 m ³ / H, and the purity (electrical conductivity) of pure water was monitored by a water quality meter 30 installed in the outlet pipe of the MB tower 4. As a result, the purity reached 0.1 μS / cm (25 ° C.) within 1 hour of passing water, and the maximum purity was 0.0
7 μS / cm (25 ° C.) was obtained.

The electric conductivity at the end of water flow is 1 μS / cm.
As a result of performing the regeneration step and the water passing step for 5 cycles at (25 ° C.), the amount of pure water taken is 39 per cycle.
stable in m ³ ~40m ^3. (Comparative Example) Raw water to be supplied to the KW tower 1 was directly sent to the MB tower 4 (that is, without using the KW tower, the D tower, and the decarbonated water tank), and regeneration and water passage were repeated in the same manner as described above. . As a result, since the purity (electrical conductivity) was 2 μS / cm (25 ° C.) in the washing and blowing step at the end of regeneration of the MB tower, water removal, mixing preparation, air mixing in the regeneration step of the MB tower 4, The full water blow and washing blow steps were repeated. The result is that after 15 minutes of cleaning blow, the value of 1 μS / cm (25
C.) purity was obtained. Also, the maximum purity when passing water is 0.4.
It was μS / cm (25 ° C.). The end point of water flow is 1 μS / c
when the m (25 ° C.), adoption water of pure water was varied significantly from one cycle per 12m ³ to 17m ^3.

For reference, Table 2 shows the analytical values of the treated water of the KW tower 1 and the treated water of the D tower 2 (supply water of the MB tower) in the examples.

[0052]

[Table 2] As can be seen by comparing the raw water in Table 1 and the treated water (decarbonated water) in the D tower in Table 2, by treating the raw water in the KW tower 1 and the D tower 2, 43% of all cations and 49 of all anions were obtained. %
Ions were removed. Further, the removed components were ions that cause various precipitates generated in the regeneration step of the MB tower 4 as described above, that is, hardness components and carbonate ions.
These removal rates are 79% for hardness components and 93 for carbonate ions.
%Met. Therefore, in the regeneration step of the MB tower 4 in the present invention, almost no precipitate is generated, and the amount of ions in the feed water of the MB tower 4 is greatly reduced. Therefore, when the MB towers of the same scale are used, as described above. The amount of pure water sampled will be significantly increased compared to the past. In other words, when the same amount of pure water is to be obtained, the amount of SCR and SAR resin charged in the MB tower is smaller than that in the conventional MB tower alone. Further, generally, the regeneration efficiency of the SCR that adsorbs the hardness component is deteriorated, but according to the present invention, most of the hardness component can be removed by the WCR 5 having a high regeneration efficiency of the KW tower 1, so that the overall regeneration efficiency is improved. Combined with this, when trying to obtain the same amount of pure water, the amount of regenerant used is also greatly reduced.

Further, in the pure water production apparatus constituted only by the conventional MB tower, the purity rises at the end of regeneration and the maximum purity at the time of passing water is worse than that of the method of the present invention.

[0054]

As described above, in the present invention, since the KW tower and the D tower are provided in front of the MB tower, the quality of the decarbonated water supplied to the MB tower is the same as that of the raw water supplied to the KW tower. Compared to water quality, a considerable amount of hardness component, alkalinity component and carbonic acid are removed. For this reason, precipitation which is a problem during regeneration of the MB tower does not occur, and the ion load on the MB tower is reduced.

Further, the pure water producing apparatus of the present invention has a KW tower. Since this regeneration can be performed at the same time as the regeneration of the SCR of the MB tower and by using the regeneration waste liquid of the SCR,
In this case, it can be regenerated in the same time as the time required for regenerating the conventional pure water producing apparatus composed of the MB tower alone, no extra regeneration time is required, and the utilization efficiency of the regenerant is increased. There is an effect such as improvement of

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of the configuration of a pure water producing apparatus of the present invention.

FIG. 2 is a flow diagram showing a configuration example of a conventional pure water production apparatus.

[Explanation of symbols]

 1 Cation exchange tower (KW tower) 2 Decarbonation tower (D tower) 3 Decarbonation water tank (DWT) 4 Mixed bed type ion exchange tower (MB tower) 5 Weakly acidic cation exchange resin (WCR) 6 Packing for decarboxylation Material 7 Strongly basic anion exchange resin (SAR) 8 Strongly acidic cation exchange resin (SCR) 9 Regeneration waste liquid outlet collector

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[Procedure amendment]

[Submission date] August 29, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

The alkali regenerant is supplied from the pipe 10 and the pressed water is supplied from the pipe 11 in the lower part of the tower, and the generated waste liquid is collected in the waste liquid outlet collector 9 and discharged from the pipe 12. Known alkali regenerants can be used. Then, decarbonated water is supplied in the same line instead of the alkali regenerant, and the regenerant filling SAR7 is extruded. After that, at the same time as supplying water from the pipe 16,
The regeneration of SAR7 is completed by cleaning the SAR7 which is supplied with decarbonated water from the pipe 20 and discharged from the pipe 12. It should be noted that raw water is continuously passed through the KW tower until the regeneration process of SAR7 is completed. See also SAR7
Although decarbonated water was used as the reclaimed water in the above description, in some cases, the KW tower treated water may be used directly. Next, SCR 8 in MB tower 4 and KW tower 1
WCR5 regeneration process is performed. That is, first, the supply of raw water supplied to the KW tower 1 is stopped and the production of decarbonated water is interrupted. Next, the acid regenerant is supplied from the lower pipe 11 of the MB tower 4 and the pressurizing water is supplied from the pipe 10, and the acid regeneration waste liquid generated thereby is recycled waste liquid outlet collector 9
To collect water. The collected acidic regeneration waste liquid is guided to the regenerant inlet pipe 28 of the KW tower 1 via the pipe 13 and brought into contact with the WCR 5 in the KW tower 1, thereby regenerating the WCR 5 and then discharged from the lower pipe 14. Let Then, the extruding process of SCR8 and WCR5 is performed by switching to the decarbonated water in the decarbonated water tank 3 instead of the acid regenerant and performing the same operation, and then the washing process of the MB tower 4 and the KW tower 1 respectively. Implement independently.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

First, 720 l of a 4% (weight%, the same applies hereinafter) caustic soda aqueous solution was introduced from the pipe 10 to 1000 l / H.
At the same time, and at the same time, decarbonated water was supplied at a flow rate of 360 l / H from the pipe 11 at the lower part of the tower as the pressed water, and was collected in the regeneration waste liquid outlet collector 9, and the alkali regeneration waste liquid was discharged from the pipe 12. Then, decarbonated water was supplied instead of the 4% caustic soda aqueous solution at the same route and at the same flow rate for 12 minutes to carry out the chemical solution extrusion step. Further piping 20 at the top of the tower
To 2300 l / H, piping 16 to 1500 at the bottom of the tower
Decarbonated water was supplied as washing water at a flow rate of 1 / H for 5 minutes at the same time to collect the liquid in the collector 9 and discharge it from the pipe 12. Up to this point, raw water was passed through the KW tower to continue producing decarbonated water.

Front page continued (72) Inventor Kazuro Watanabe 1-5-17 Dojima, Kita-ku, Osaka-shi, Osaka Dojima Grand Building Organo Co., Ltd. Osaka Branch

Claims (3)

[Claims] 1. A cation exchange column filled with a weakly acidic cation exchange resin, a decarboxylation device, a decarbonation water tank, a strongly acidic cation exchange resin and a strongly basic anion exchange resin in the same column. It has a packed mixed-bed type ion exchange tower, and the raw water is passed through the cation-exchange tower, the decarbonation device, the decarbonated water tank, and the mixed-bed type ion-exchange tower in order, and pure water is mixed from the mixed-bed type ion-exchange tower. An apparatus for producing pure water, which is configured to take out water. 2. The method for regenerating a pure water production apparatus according to claim 1, wherein the acid regenerant is passed through the strong acid cation exchange resin in the mixed bed type ion exchange tower. And a weak acid cation exchange resin in the cation exchange tower by regenerating the acid regeneration waste liquid generated by the above-mentioned replenishment to the cation exchange tower to regenerate the pure water producing apparatus. . 3. The method of regenerating the pure water producing apparatus according to claim 1, wherein the strong basic anion exchange resin in the mixed bed ion exchange column is first regenerated, and then the strong acid cation exchange resin is regenerated. Along with the regeneration of the weakly acidic cation exchange resin by sending the acidic regeneration waste liquid generated by the regeneration of the strongly acidic cation exchange resin to a cation exchange column, and while regenerating the strong basic anion exchange resin, A method for regenerating a pure water producing apparatus, characterized in that raw water is passed through a cation exchange tower and the treated water is used in a step of regenerating a strongly basic anion exchange resin.