KR900001370B1 - Method and apparatus for desalting of water by ion-excanhge - Google Patents

Abstract

The method employs a separate intermediate me dium resin for separating deionczed resin from the mult-bed demineraling filter tank. A separate tank is used for storing and reeycling the inlermediate resin of inactive type or cation or anion exchange type. The tank is also used for separating cation resin from anion resin in the multi-bed and for regenerating cation resin, the anion exchange resin being transferred to another regeneration tank.

Description

Multiple desalination method and apparatus for regeneration type mixed phase desalination equipment outside tower

FIG. 1 is a schematic process chart showing that the air is waiting to regenerate a mixed phase ion exchange resin tower resin which has lost its desalting function.

2 is a schematic process diagram of the step of transferring the intermediate resin for resin separation.

3 is a schematic process diagram of the step of transferring the mixed resin having the desalting function to the separation column and the cation regeneration tower.

4 is a schematic process diagram of the step of separating the mixed resin by the backwash process.

5 is a schematic process diagram of the step of transporting the anion exchange resin for regeneration.

6 is a schematic process diagram of the step of transferring the intermediate resin for resin separation.

7 is a schematic process diagram of a step in which a resin is regenerated by a regenerant.

8 is a schematic process diagram of the step of transferring the cation exchange resin.

9 is a schematic process diagram of the step of transporting the anion exchange resin is completed regeneration.

10 is a schematic process diagram of the step of transferring the resin after the regeneration is completed.

* Explanation of symbols for main parts of the drawings

1 mixed bed ion exchange resin tower 2 separation column and cation regeneration tower

3: anion regeneration tower 4: resin storage tower

5: Intermediate Media Resin Storage Tower 6: Mixed Resin with No Desalting Function

7: intermediate resin (intermediate resin) 8: anion exchange resin

9: cation exchange resin 10: compressed air inlet pipe

11: regeneration water inlet tube 12: cation regeneration inlet tube

13: anion regeneration agent inlet tube 14: mixed resin

The present invention utilizes a separate active resin or an inert resin as an intermediate medium resin for separation in an out-of-column regeneration type multiphase desalination plant, and may be selected from one of two different types of resins: cation exchange resins and anion exchange resins that have lost the desalting function. It is an object to minimize the amount of sodium-type cation exchange resin to be incorporated into the plural demineralization water flow system and to obtain a high purity treated water by using a method of separating the resin.

In steam turbine installations and other industrial installations, water is often used for steam generation or other purposes. In particular, the water supplied to the steam generator of the steam turbine power generation equipment should be pure water from which solids and ionic substances which cause corrosion and corrosion on the surface of turbine blades, tubes, etc. are thoroughly removed.

Although component be a plurality circulates a closed system that cause surface pitting and corrosion are there is stored in the plurality through a leak in the inlet or the cooling water system in the makeup water, The removal of such components is hydroxyl ions of the strongly basic resin (OH ^- ) And hydrogen ions (H ⁺ ) or ammonium ions (NH ₄ ⁺ ) of strongly acidic resins and substitution reactions. It is known that the best results can be obtained in a mixed-phase ion exchange resin tower.

When the plural passes through the mixed-phase ion exchange resin tower, the heavy metal oxides or ionic substances contained in the plural are mostly removed by the ion exchange resin, and the ion exchange resin gradually loses its function. Therefore, the cation exchange resin which has lost the desalting function is regenerated by a strong acid such as sulfuric acid or hydrochloric acid, and the anion exchange resin is regenerated by a strong alkali such as caustic soda.

However, after the regeneration was completed, the biggest problem that emerged in operating the desalination plant was ion leakage. Here, the ion leakage does not mean the ion leakage from the plurality caused by the impurity ions contained in the plurality during the normal operation of the mixed phase ion exchange resin tower, which is caused by the ion exchange resin, but is not a regeneration facility. Ion leakage from a kind of contaminated resin, especially sodium ions (Na ⁺ ) and chlorine, which reacted with unwanted chemicals in the process of regenerating ion exchange capacity by treating chemically deficient ion exchange resins with chemicals Ion leakage.

Traditionally, resin separation methods have been backwashed, relying on the technology of hydro-separation, where light anion exchange resins are sent to the top and heavy cation exchange resins are dropped to the top.

However, such a simple method of hydraulic separation consists of a cation exchange resin and an anion exchange resin and can be largely separated into a heterogeneous resin. However, the heterogeneous resin of the mixed layer formed around the boundary layer cannot be completely separated.

The reason was due to the resin being broken during operation of the multiple desalination plant. The crushed resin is distributed in the vicinity of the boundary layer between the crushed cation exchange resin and the anion exchange resin because the technique of hydraulic separation depends not only on the specific gravity of the resin but also on the particle size of the resin to form a mixed layer.

Therefore, no matter how careful the transfer of anion exchange resin from the cation exchange resin to a separate tower, it is inevitable that the cation exchange resin of the mixed layer formed around the heterogeneous resin boundary layer is swept together with the anion exchange resin. a small amount of cation exchange resin into been the cause of sodium ion (Na ⁺⁾ leakage, or Anti-anion exchange resin remaining on the number cation exchange resin are chlorine ions and sulfate ions were to leak causes such as (SO ^{- -} _4). Among these leaks, sodium ions (Na ⁺ ) or chlorine ions that enter the ion exchange resin, especially those whose surfaces are contaminated with iron oxide, remain inside the ion exchange resin without being removed, and leak through the surface of the ion exchange resin during the desalting process. In some cases, ammonia perfusion occurs due to ammonia injected to control pH (PH) and releases sodium ions (Na ⁺ ). Mainly high pressure perfusion boiler or water reactor type or pressurized water nuclear power plant thermal power plant is sodium ions and chloride ions in a few Phi ratio (PART PER BILLION) because it strictly regulate the sodium ions (Na ⁺⁾ and chlorine ion content in water at multiple processing Even if it leaks, it is very serious in multiple systems and is not desirable at all.

As mentioned above, in order to reduce ion leakage, especially sodium ion (Na ⁺ ) leakage, which is the biggest problem during operation of the multiple desalination plant, a new process is applied over the multiple desalination method using the conventional resin separation method. Additional special desalination methods have emerged. That is, after regeneration of the anion exchange resin by caustic soda, a small amount of cation exchange resin swept together with the anion exchange resin using a large amount of ammonia solution, the sodium (Na ⁺ ) type cation exchange resin is ammonium (NH ₄ ⁺ ) Is substituted with cation exchange resin.

However, this method consumed a large amount of ammonia and regeneration period to remove relatively small amount of sodium (Na ⁺ ), but could not completely remove sodium (Na ⁺ ).

In another method, a small amount of cation exchange resin swept together with the anion exchange resin after the regeneration of the caustic soda is completed using sodium hydroxide (Na ⁺ ) solution using high purity calcium hydroxide (Ca (OH) ₂ ) solution. There is a method of replacing the type cation exchange resin with a calcium (Ca ⁺⁺ ) type cation exchange resin, which is insoluble in the piping and anion exchange resin after the injection of the calcium hydroxide (Ca (OH) ₂ ) solution is completed. Calcium hydroxide (Ca (OH) ₂ ) particles had to be thoroughly washed to prevent coagulation. In addition, this method requires additional injection equipment and additional chemicals for the injection of calcium hydroxide (Ca (OH) ₂ ), which is inexpensive, requires a lot of regeneration time, and requires careful attention to operation.

When the chemical method for preventing ion leakage has a problem as described above, in order to prevent the cation exchange resin from incorporating onto the anion exchange resin, it corresponds to the middle of the specific gravity of the anion exchange resin and the specific gravity of the cation exchange resin. The idea was to use some intermediate media to separate the resin.

That is, a plurality of desalination is performed by using a method of flotation of the anion exchange resin from the cation exchange resin using a liquid having a specific specific gravity corresponding to the middle of the cation exchange resin and the anion exchange resin.

This intermediate specific gravity solution was an 8-16% caustic soda solution, which was successful in separating an resin by forming an anion exchange resin layer on the top, a caustic soda solution in the middle, and a cation exchange resin layer on the bottom. However, this method inevitably comes in contact with a strong alkaline caustic soda solution, even with a small amount of cation exchange resin, and it is not economical because it requires a large amount of caustic soda solution and also requires a large amount of washing water. The regeneration process is complex and has the drawback that a lot of regeneration time is consumed.

The present invention provides a method of eliminating the problems of all the above-described processes by using an active resin mixed with a certain amount of an inert resin or a cation exchange resin and an anion exchange resin as an intermediate for resin separation during the resin separation process. To provide. That is, in addition to the mixed resin composed of a cation exchange resin and an anion exchange resin for the purpose of plural desalination before the backwashing process, an active resin composed of a certain amount of an inert resin or a cation exchange resin and an anion exchange resin for the purpose of separating resins only After addition by using as a medium resin, backwash separation is performed to create a heterogeneous resin state. In this state, a certain amount of anion exchange resin for the purpose of desalting is transferred to a separate storage tower for regeneration, and a certain amount of resin corresponding to the volume of the intermediate medium resin added before the backwashing process, that is, the remaining inert resin or Some anion exchange resins and cation exchange resins are recovered again.

In the present invention, a separate intermediate medium resin storage tower using a predetermined amount of inert resin or an active resin mixed with a cation exchange resin and an anion exchange resin as an intermediate medium resin for separation is installed to facilitate the operation of the resin transfer process. In the case of the inert resin, the volume of the intermediate medium resin is preferably 15% of the volume of the interphase resin for the purpose of desalting function. On the other hand, in the case of active resins, about 20% of the volume of the mixed resin in one mixed ion exchange resin tower for desalting function is preferable, and the volume ratio of the cation exchange resin and the anion exchange resin is 1: 1 or desalted. It consists of the inverse of the volume ratio of the cation exchange resin and anion exchange resin of the objective intermixture resin.

Therefore, the schematic process of the present invention will be described with reference to the drawings. 1 to 10 are simplified illustrations of the process diagram of the apparatus for carrying out the present invention. The connection between the tanks is made by appropriate piping and electric equipment, and pumps and air for transporting resin, water, and regenerating agent are provided. The conveying compressor and the like are not shown in the same manner as the conventional methods known to date. This process diagram shows a mixed bed ion exchange resin tower (1) representing a plurality of desalination processes, a separation tower and a cation regeneration tower (2) for separating resin transferred from the mixed bed ion exchange resin tower (1) and regenerating a cation exchange resin. , An anion regeneration tower (3) for regenerating anion exchange resin and a resin storage tower (4) for storing resins transferred after the regeneration is completed in the separation column, the cation regeneration tower (2) and the anion regeneration tower (3), respectively. And an intermediate resin storage tower (5) for storing the medium resin.

Meanwhile, the regeneration water introduced through the regeneration water inlet pipe 11 is used as flowing water, resin transfer water, backwash water, or resin mixed water depending on the process, and the compressed air introduced through the compressed air inlet pipe 10 is used for resin mixing. It is used for resin transfer.

FIG. 1 shows that the mixed bed ion exchange resin tower 1 which has lost the desalting function is waiting for stopping operation and regeneration.

2, the intermediate resin 7 stored in the intermediate medium resin storage tower 5 is separated into the separation tower and the cation regeneration tower before the mixed resin 6 having lost the desalting function is transferred to the separation and cation regeneration tower 2. 2) shows the steps to transfer. The transfer of the intermediate resin 7 takes place in the following manner. That is, while supplying sufficient and appropriate amount of compressed air and flowing water through the compressed air inlet valve (I-1) at the top of the tower and the inlet / outlet valve (I-5) at the bottom, the intermediate resin outlet valve (I-6) The intermediate resin (7) is separated from the intermediate medium resin storage tower (5) through the resin inlet valve (C-7) and the cationic regeneration tower is supplied through the resin inlet valve (I-7). Is transferred to (2).

As the intermediate resin (7) is transferred, the air discharge valve (C-4) and the drain valve (C-11) of the separation column and the cationic regeneration tower (2) are opened. This process is performed until the transfer of the intermediate resin (7) is completed. Continues.

3 shows a step of transferring the mixed bed resin 6 from the mixed bed ion exchange resin tower 1 to the separation tower and the cationic regeneration tower 2 in order to recover the mixed bed resin 6 having lost the desalting function. That is, while supplying a sufficient and appropriate amount of compressed air and flowing water through the compressed air inlet valve (P-1) at the top of the tower and the oil inlet valve (P-5) at the bottom, the resin inlet and outlet valve (P-7) By supplying the resin transfer water through the mixed phase resin, the mixed phase resin is transferred from the mixed phase ion exchange resin tower 1 to the separation tower and the cationic regeneration tower 2 through the resin outlet valve P-8.

At the same time, the air discharge valve (C-4), the drain valve (C-11) and the resin inlet valve (C-6) of the separation column and the cation regeneration tower 2 are opened. In order to transfer the remaining resin remaining at the bottom of the tower after most of the resin transfer is completed, a sufficient and appropriate amount of compression is continuously performed through the compressed air inlet valve (P-1) and the remaining resin feed water inlet valve (P-3). The process is completed by supplying air and resin transfer water.

4 shows a process of separating the intermediate resin 7 and the mixed resin used for desalting into anion exchange resin 8 and cation exchange resin 9 by backwashing. Water is generally used as a means for separation, in which cation exchange forms a lower layer by flowing a flow rate sufficient to float the light anion exchange resin (8) to the upper portion of the cation exchange resin (9). The phase can be divided by the resin 9 and the anion exchange resin 8 forming a high layer.

The hydraulic separation of the mixed resin by the backwashing process is carried out through the following process. That is, the backwash water discharge valve C-2 is opened for supplying backwash water with a sufficient flow rate through the backwash water outlet valve C-10 and for discharging the backwash water.

5 shows a process for transferring the anion exchange resin 9 from the separation column and the cation regeneration tower 2 to the anion regeneration tower 3 through the primary resin transfer path.

In this process, the flowing water discharge valve (A-5) at the bottom of the anion regeneration tower (3) is opened, and at the same time, the flowing water is supplied to the lower portion of the separation tower and the cation regeneration tower (2) through the inlet inlet valve (C-9), By supplying sufficient and appropriate compressed air to the compressed air inlet valve (C-3), the anion exchange resin 8 is transferred through the resin outlet valve A-4. At this time, the air discharge valve (A-2), the backwash water discharge valve (A-8) is opened.

6 shows a step of transferring the resin separation intermediate resin 7 from the separation column and the cationic regeneration tower 2 to the intermediate medium resin storage tank 5 through the secondary resin transfer path. Before transporting the intermediate resin (7), the lower intermediate drain valve (I-4) of the intermediate medium resin storage tower (5) is opened, and through the compressed air inlet valve (C-3) above the separation column and the cation regeneration tower (2). After supplying compressed air to pressurize the inside of the tank, resin flow water of appropriate flow rate is supplied to the inlet / outlet valve (C-9).

At the same time, the resin outlet valve (C-8) is opened to transfer the intermediate resin (7) from the separation column and the cation regeneration tower (2) to the intermediate medium resin storage tower (5). At this time, the resin inlet valve I-3 is also opened.

7 shows a process in which each ion exchange resin completely separated on the ground of the resin separation intermediate resin (7) is regenerated in the separation column, the cation regeneration tower (2) and the anion regeneration tower (3) by a suitable regenerant. Shows. The appropriate concentration of regenerant for regenerating the cation exchange resin (9) is supplied through the cation regenerant inlet valve (C-5), and the operation of the regenerant discharge valves (C-11) and (C-12) is regenerated. Optionally open as the cycle progresses. On the other hand, the regeneration process of the anion exchange resin (8) is supplied through the anion regeneration agent inlet valve (A-3) of the appropriate concentration, and the regeneration agent discharge valve (A-5) is opened to discharge the regeneration waste liquid.

8 shows a step in which the regenerated cation exchange resin 9 is transferred from the separation column and the cation regeneration tower 2 to the resin storage tower 4. This process opens the air discharge valve (R-2) of the resin storage tower (4) and the resin transfer water and the oil discharge valve (R-6), and the compressed air inlet valve (top of the separation column and the cation regeneration tower 2) ( While supplying adequate and sufficient compressed air through C-3), the resin feed water and flow water at the proper flow rate from the bottom of the tower are transferred through the resin feed water inlet valve (C-14) and the oil inlet valve (C-9). Start by feeding At the same time, the cation exchange resin 9 is transported through the resin outlet valve (C-13) at the bottom of the separation column and the cation regeneration tower (2) and the resin inlet valve (R-4) at the top of the resin storage tower (4). .

FIG. 9 shows a process of transferring the regenerated anion exchange resin from the anion regeneration tower 3 to the resin storage tower 4 and mixing the regenerated cation exchange resin. That is, firstly, the resin storage tower 4 opens the air discharge valve R-2 and the resin transport water discharge valve R-6 while the compressed air inlet valve A on the upper part of the anion regeneration tower 3 is opened. -1) to supply compressed air, and to supply the resin feed water through the resin feed inlet valve (A-6) at the bottom of the tower, and at the same time flow the resin outlet valve (A-7) at the bottom of the anion regeneration tower (3). Open the inlet valve (A-9) and the resin inlet valve (R-4) at the top of the resin storage tower (4) to transfer the anion resin. When the transfer of the anion resin is completed, the resin mixture water and the resin mixing compressed air from the bottom of the resin storage tower are mixed with the resin mixing inlet valve (R-7) and the resin mixing compressed air from the bottom of the resin storage column to mix the respective resins. While supplying through the inlet valve R-5, the air discharge valve R-2 and the drain valve R-9 are opened to mix the resin.

FIG. 10 shows that the mixed bed resin 14, which has been regenerated, is transferred from the resin storage tower 4 to the mixed bed ion exchange resin tower 1 and is in operation standby. This process is performed by compressing the upper portion of the resin storage tower 4 with the air discharge valve P-2 and the flowing water and the resin transfer water discharge valve P-6 on the mixed phase ion exchange resin tower 1 opened. While supplying compressed air through the air inlet valve (R-1) and supplying the resin feed water at an appropriate flow rate through the water inlet valve (R-7) and the resin feed water valve (R-10) at the bottom, The mixed resin 6 is completed through the resin outlet valve R-8 at the bottom of the storage tower 4 and the resin inlet valve P-4 at the upper portion of the mixed ion exchange resin tower 1.

When the plural desalination plant is operated according to the present invention having the above characteristics, the following improvements are made.

First, the anion exchange resin and the cation exchange resin are almost completely separated, thereby minimizing ion leakage during operation after regeneration, thereby maintaining high-purity treated water quality and increasing water volume.

Second, it prevents chemical destruction of resin by cross-contamination and minimizes contamination of resin, so that the durability of resin is kept longer and the ion exchange operation capacity of resin is kept higher.

Third, the simplification of the regeneration process gives the operator a sense of stability for the facility and at the same time reduces the regeneration time.

Fourth, less washing water is required, no additional chemicals are required.

Fifth, by using a separate mediator resin storage tower to simplify the complexity of the device and facilitate resin separation and recovery.

Claims (12)

Ion exchange consisting of an intermediate media resin for resin separation and a separate mediator resin storage tower for the use and recovery of the intermediate media resin Resin Separation and Plural Desalting Method. The method of claim 1, wherein an inert resin is used as the intermediate resin for resin separation. The method according to claim 1, wherein the intermediate resin for resin separation uses a certain amount of active resin composed of a cation exchange resin and an anion exchange resin. The method according to claim 1, wherein the intermediate resin in the intermediate resin storage tower is transferred to the separation column and the cation regeneration tower in order to separate the cation exchange index and the anion exchange index of the mixed phase which have lost function. The method of claim 1, wherein the anion exchange index is transferred from the separation column and the cation regeneration tower to the anion regeneration tower based on the intermediate resin. The method of claim 1 wherein the intermediate resin is recovered back to the intermediate resin storage tower. A method of purifying by passing a plurality of phases on a mixed resin composed of a cation exchange resin and an anion exchange index regenerated by using any one of claims 1 to 6. Ion-exchange resin consisting of semi-intermediate resin for resin separation and separate mediator resin storage tower for use and recovery of intermediate media resin Separation and Plural Desalting Apparatus. 9. The apparatus according to claim 8, wherein the intermediate medium resin in the intermediate medium resin storage tower is transferred to the cation regeneration tower for the separation of the cation exchange resin and the anion exchange index in the ineffective state. The apparatus of claim 8, wherein the anion exchange index is transferred from the separation column and the cation regeneration tower to the anion regeneration tower based on the intermediate resin. The apparatus of claim 8, wherein the intermediate resin is recovered back to the intermediate resin storage tower. 12. An apparatus for refining a plurality of passages over a mixed-phase resin composed of a cation exchange resin and an anion exchange index regenerated by using any one of claims 8 to 11.

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