KR20040082228A - Used water return method for mixed bed ion exchange resin tower - Google Patents

Abstract

PURPOSE: A method for recovering used water of mixed bed ion exchange resin tower is provided to recycle a portion of used water having good quality. CONSTITUTION: The method comprises a step of regenerating ion exchange resin by supplying a regenerating agent into an ion exchange tower; first rinsing step of rinsing waste regenerating solution remained on ion exchange resin; first, second, third and fourth fill up steps of exhausting gas contained in the ion exchange tower; and a final rinsing step of finally rinsing the waste generating solution on the ion exchange resin to use treated water having a required quality level or more only in the process before converting the gas-stripped solution into the deionized water treatment state, wherein discharge water (used water) discharged in the step following the third fill up step is recovered into a pretreatment tank for storing treated water in which suspended materials contained in raw water are removed.

Description

Use of water recovery in mixed-phase ion exchange resin regeneration tower {USED WATER RETURN METHOD FOR MIXED BED ION EXCHANGE RESIN TOWER}

The present invention relates to a method for recovering water used in a mixed-phase ion exchange resin regeneration tower, and more particularly, to return a part of the used water used in the regeneration process of a mixed phase ion exchange resin regeneration tower to be recycled. The present invention relates to a method for recovering water used in a mixed bed ion exchange resin regeneration tower.

High purity water, that is, ultrapure water, requires as little as possible the amount of impurities to be contained in the manufacturing process of semiconductors and the manufacture of pharmaceuticals. In particular, the semiconductor integrated circuit (LSI) cleaning process uses a large amount of ultrapure water. The purity of this ultrapure water greatly influences the yield of the product, and nowadays, higher purity water is required for the cleaning of high level LSI (1 megabit, 4 megabit, etc.).

Conventional ultrapure water production apparatus is a raw water tank (1) for supplying raw water as shown in Figure 1, and the first heat exchanger (3) for maintaining the temperature of the raw water supplied from the raw water tank (1) at a predetermined temperature And a sand filter tower 5 for pre-filtering the primary solid matter contained in the supplied raw water, and a pre-treatment tank 7 for storing the raw water processed through the sand filter tower 5.

In addition, the pretreatment carbon tower 9 for removing odors and removing secondary solids (eg, chlorine) contained in the treated water supplied through the pretreatment tank 7, and the cation removal tower 11 for removing cations. ), A degassing tower 13 for removing carbon dioxide gas contained in the treated water, an anion removing tower 15 for removing anions contained in the treated water, and a pure water tank 17 storing the treated water. It is composed.

Meanwhile, the second heat exchanger 19 which maintains the pure water supplied from the DEIONIZED WATER storage tank 17 at a temperature (for example, 24 ° C.) of the FAB and the supplied pure water are irradiated with ultraviolet rays to sterilize microorganisms. The first UV filter sterilizer 21, the first micro filter 23 for filtering microorganisms sterilized by the first UV sterilizer 21, and the water passing through the first micro filter 23 are subjected to a predetermined pressure. The first pressure pump 25 to be pumped by pressure is configured.

Next, the first reverse osmosis membrane device 27 which receives the pressurized water by the first pressurizing pump 25 and first filters the ions or organic matter contained in the water, and removes the dissolved oxygen contained in the filtered water. A dissolved oxygen remover 29, an organic matter processor 30 for decomposing and converting low-molecular organic matter contained in water into ions, and a mixed phase ion exchange resin regeneration tower 31 for finally removing the converted ions.

Next, the primary ultrapure water tank 33 for storing the primary ultrapure water passing through the mixed phase ion exchange resin regeneration tower 31 and the microorganisms contained in the water supplied to the primary ultrapure water storage tank 33 are finally A second UV sterilizer 35 for sterilization, a second micro filter 37 for finally removing microorganisms sterilized by the second UV sterilizer 35, and a second pressure pump for pressurizing the filtered water secondly. (39) and the secondary reverse osmosis membrane device 41 for finally removing the ions or organic matter contained in the pumped water and the secondary pure water storage tank 43 for storing the final filtered ultrapure water.

As shown in FIG. 2, the mixed phase ionized water regeneration tower 31 has a support member 31b installed at a lower portion of the ion exchange tower 31a, and a mixed phase of a strong acid cation exchange resin and a basic anion exchange resin is supported thereon. It is. An upper distributor 31c for supplying a regenerant is installed at an upper portion of the ion exchange tower 31a, and a lower distributor 31d for supplying a regenerant is provided at a lower portion of the support member 31b of the ion exchange tower 31a. have.

During the regeneration of ion exchange resins, strong acid cation exchange resins and basic anion exchange resins are separated by specific gravity. As a result, as shown in FIG. 2, an anion exchange resin layer 31e is formed on the upper layer, and a strong acid cation exchange resin layer 31f is formed on the lower layer. And the collector 31g which discharges a regeneration waste liquid is provided in the position of this separation boundary surface.

The ion exchange tower 31a is provided with a plurality of fluid distribution pipes 31h and 31i for circulating various fluids during processing and regeneration.

The ion exchange resin regeneration tower 31 constructed as described above is treated with deionized water in the resin layer filled with positive and negative ions in order to further treat the deionized treated water in the pure water treated in the pretreatment process with the required water of higher purity. Pass the water from the top to the bottom to carry out the water purification process.

However, since the exchange capacity of each positive and negative ion becomes saturated during the water purification process, the positive and negative ion exchange resin should be regenerated by using a regenerant.

The regeneration process is performed by the process as shown in FIG.

First, a BACK WASH step S100 is performed.

Backwashing refers to the process of passing water from the bottom of the ion exchange column to wash off the resin layer and to wash it off because the suspension is deposited in the resin layer when the treatment liquid is passed through. At this time, the flow rate of the resin layer is appropriately increased by 50 to 80%, and thus sufficient space is required at the top of the resin layer.

Next, a regeneration process S300 is performed.

Regeneration process (S300) is sodium hydroxide (NaOH) spray (S310), sodium hydroxide cleaning (S320), backwashing (S330), stabilization (SETTLEMENT) step (S340), hydrochloric acid (HCl) spray (S350), hydrochloric acid (HCl) It includes a cleaning step (S360).

The above-described process is performed by varying the number of repetitions according to the degree of reproduction.

Next, the first cleaning process S500 is performed.

The washing process is a process of completely washing the remaining solution components remaining in each positive and negative ion exchange resin once again, and water is introduced into the upper portion of the ion exchange column and drained to the lower portion.

Next, the first drain step S700 is performed.

The drain drains all the regeneration water remaining in the ion exchange column to the lower portion of the ion exchange column.

Next, the SETTLEMENT step S900 is performed.

SETTLEMENT means that the cation exchange resin, which has a high specific gravity, sinks at the bottom due to the specific gravity difference between the cation exchange resin and the anion exchange resin through the stoppage of the expanded resin layer, and that the relatively small anion exchange resin has a cation exchange. It refers to a state where it is separated and sinks on the resin top.

Next, the first and second fill up steps S1100 and S1700 are performed.

Fill up refers to a process of discharging air and gas in an ion exchange column, and a process of exhausting water while supplying water to a resinous phase in a state where resin is mixed.

Second and third drain (S1300, S1900) and stabilization (S1500) step is further proceeded to the first and second fill-up step (S100, S1700).

Here, the second and third drains (S1300 and S1900) and the stabilization (S1500) steps play the same role as the above-described primary drain step (S700) and the stabilization step (S900).

Next, the first and second mixing (MIXING) step (S2100, S2300) is performed.

Mixing is a process for mixing the regenerated cation and anion exchange resins into an ultrapure water treatment state. In the secondary mixing step (S2300), nitrogen (N ₂ ) is supplied to the lower portion of the ion exchange tower (31a).

Next, the third and fourth fill-up steps S2500 and S2700 are performed, and the process is performed in the same manner as the first and second fill-up steps S1100 and S1700.

Next, a final washing step (S2900) is performed.

The final cleaning step S2900 includes a final first and second cleaning steps S2910 and S2930 and a manual cleaning step S2950, and the final first and second cleaning steps are automatically performed by a predetermined program. And, in the manual cleaning step (S2950) the cleaning operation is made manually by the operator.

As described above, in the regeneration operation as described above, the supply water is regenerated as shown in FIG. 4, and pure water is supplied from the pure water storage tank 17 in the first and second washing steps S300 and S500. Ultrapure water is supplied from the primary ultrapure water storage tank 33 in the fill-up phase (S1100, S1700, S2500, S2700) and the final washing step (S2900: final primary cleaning (S2910), final secondary cleaning (S2930), manual cleaning (S2950)). do.

After the process, the used water is recovered and reused into the waste water tank 45, the heavy water tank 47, and the pure water storage tank 17, respectively. The used water used in the regeneration (S300) step is the waste water tank 45. It is recovered.

Next, the water used in the first washing step (S500), 1,2,3,4th filling-up step (S1100, S1700, S2500, S2700) and the final first washing step (S2910) is recovered to the water tank (47), In some cases, when the TOC value is high, it is recovered to the waste water tank 45.

Next, the used water used in the final secondary washing step (S2930) is recovered to the pure water storage tank 17, the used water used in the manual washing step (S2950) is recovered to the heavy water tank 47 and the pure water storage tank (17). .

Manual cleaning (S2950) takes about 30 minutes once operating time, the water used until the operating time is 10 minutes is recovered to the water tank (47), the water used after that is a pure water storage tank Recovered to (17).

However, in the related art, although most of the feed water supplied to the regeneration process as described above uses the ultrapure water of the primary ultrapure water storage tank 33, even though the water used for the regeneration process is in good condition, the final 2 Most of the remaining water except for the used water used in the car washing step S2930 has been recovered to the water tank 47.

Accordingly, the present invention has been made to solve the above problems, an object of the present invention is to improve the recovery state of the use water used in the regeneration process to prevent excessive use of good water quality water is discarded The present invention provides a method for recovering water used in a regeneration tower.

1 is a block diagram schematically showing the configuration of a conventional ultrapure water producing system;

2 is a configuration diagram of the mixed-phase ion exchange resin regeneration tower of FIG.

3 is a view illustrating a regeneration process of the mixed-phase ion exchange resin regeneration tower of FIG. 2;

4 is a view showing a state in which the water used in each regeneration step is recovered in the regeneration process of the mixed-phase ion exchange resin regeneration tower of FIG. 3;

5 is a view showing a state in which the water used in each regeneration step is recovered in a regeneration process of a mixed bed type ion exchange resin regeneration tower according to an embodiment of the present invention;

6A and 6B are measurement tables showing the results of measuring water quality at each stage of the mixed-phase ion exchange resin regeneration tower.

<Explanation of symbols for the main parts of the drawings>

7: pretreatment tank 17: pure water storage tank

31: mixed phase ion exchange resin regeneration tower 45: waste water tank

47: Sewage Water Tank

In order to achieve the above object, the present invention comprises the steps of regenerating the ion exchange resin by supplying a regenerant inside the ion exchange ring tower; A first washing (RINSE) step of washing the regeneration waste liquid remaining in the ion exchange resin; 1,2,3,4th fill up step of discharging the gas contained in the ion exchange tower (FILL UP) step; And a final rinse step of final washing of only the treated water above the required water quality for use in the process prior to conversion to pure water. Effluent discharged from the subsequent step including the third fill-up step is characterized in that it is recovered to the pre-treatment tank for storing the treated water from which the suspended matter contained in the raw water is removed.

Next, with reference to Figures 5 and 6a, b will be described in more detail with respect to the method for recovering the water used in the ion exchange resin regeneration tower according to an embodiment of the present invention.

The same parts as those shown in FIGS. 1 to 4 are denoted by the same reference numerals and detailed description thereof will be omitted.

Another point of the present invention lies in the method of recovering the water used in each step.

As shown in FIG. 5, the used water used in the regeneration step S300 is recovered to the waste water tank 45, and in the first washing step S500, the first filling up step S1100, and the second filling up step S1700. The used water is recovered to the heavy water tank 47 or to the waste water tank 45 when the organic matter removal rate is low.

On the other hand, the used water used in the third and fourth fill-up step (S2500) and the final cleaning step (S2900) is recovered to the pretreatment tank (7).

By using the method as described above, the number of water used in the third and fourth fill-up steps (S2500, S2700) and the final primary cleaning step (S2910) and the manual cleaning step as the conventional state of good water quality as in the prior art A portion of the used water used in S2950 is prevented from being discarded into the heavy water tank 47.

Next, the water used in the third and fourth fill-up steps S2500 and S2700 and the final cleaning stage S2900 can be recovered to the pretreatment tank 7 with reference to the tables shown in FIGS. 6A and 6B. Let's explain.

As shown in the table, the result of measuring the water quality of the water used in the subsequent steps including the first washing step (S500) is much lower than the TOC value (600 to 1000) in the pretreatment tank (7). It can be seen that the water quality can be sufficiently recycled.

As described above, the present invention provides an advantage of reducing the amount of water used by recovering and recycling the used water having good quality in the pretreatment tank among the used water used to regenerate the mixed phase ion exchange resin.

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

Claims (1)

Regenerating the ion exchange resin by supplying a regenerant into the ion exchange column; A first washing (RINSE) step of washing the regeneration waste liquid remaining in the ion exchange resin; 1,2,3,4th fill up step of discharging the gas contained in the ion exchange tower (FILL UP) step; And A final rinse step of final washing of the treated water above the required water quality prior to conversion to pure water for use in the process; Effluent discharge water (used water) discharged in subsequent steps including the third fill-up step is recovered in a pretreatment tank for storing the treated water from which the suspended substances contained in the raw water are removed. Reclaimed water recovery method.