KR890004710B1 - Method and apparatus for regeneration of ion-exchange resin in mixed-bed ion-exchanger - Google Patents

Abstract

Mixed ion exchange resin of cation and anion exchange resins is mixed with the activated ion exchange resin of cation and anion exchange resins, which is for intermediating, at the ratio of 1:0.15 wt. volume. The separation and regeneration of the mixed resin is carried out in the tower. The top chamber of the tower separates the mixed exchange resin and regenerates the cation exchage resin in backwashing. The bottom chamber of the lower stores the intermediated resin.

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.

Figure 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.

Figure 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 tank 6: Mixed resin that lost its desalting function

7: 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

P-1: Compressed air inlet valve P-2: Air exhaust valve

P-3: Resin Inlet Valve P-4: Resin Inlet Valve

P-5: Oil Inlet Valve P-6: Oil & Resin Transfer Valve

P-7: Resin transfer inlet valve P-8: Resin outlet valve

C-1, C-3: Compressed air inlet valve C-2: Inflow valve

C-4: Air exhaust valve C-5: Cation regeneration inlet valve

C-6, C-7: Resin Outlet Valve C-8, C-12: Resin Outlet Valve

C-9: Lower drain valve C-10, C-11: Resin feed inlet valve

C-13: Oil inlet valve C-14: Backwash inlet valve

C-15, C-16: Regeneration agent discharge valve C-17: Backwash discharge valve

A-1: Compressed air inlet valve A-2: Air exhaust valve

A-3: Anion regeneration agent inlet valve A-4, A-7: Resin outlet valve

A-5: Oil discharge valve and regenerant discharge valve A-6: Resin transfer inlet valve

A-8: Backwash drain valve A-9: Oil inlet valve

R-1, R-5: Compressed air inlet valve R-2: Air exhaust valve

R-3, R-4: Resin Inlet Valve R-6, R-7: Oil Inlet Valve

R-8: Resin Outlet Valve R-9: Drain Valve

The present invention utilizes a separate active resin or inert water as an intermediate medium resin for separation in a regeneration type multiphase desalination plant of a tower, and has a deionization function. By using the method of separating arbitrary resins, it is an object to minimize the amount of sodium-type cation exchange resins to be incorporated into the plural demineralization water flow system to obtain treated water of high purity.

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 plural cycles are closed, components that cause surface viscosity and corrosion accumulate in the plural due to inflow of supplemental water or leakage of cooling water system. It is made by substitution reaction with hydrogen ions (H ⁺ ) or ammonium ions (NH ₄ ⁺ ) of strongly acidic resins, and it is known that the best results can be obtained in a mixed bed 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 means that the impurity ions contained in the plurality during the normal operation of the mixed phase ion exchange resin tower are not removed by the ion exchange resin. It does not mean the leakage of ions from the plurality, but rather a kind of contaminated resin that reacts with unwanted chemicals in the process of regenerating the ion exchange capacity by treating the ion exchange resin that has lost its function in the regeneration facility. This refers to ion leaks, especially sodium ions (Na ⁺ ) and chlorine ions.

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 of the tower. However, such a simple hydro separation method was able to largely separate the heterologous resin composed of the cation exchange resin and the anion exchange resin, but could not completely separate the heterogeneous resin of the mixed layer formed around the boundary layer. 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 entering caused a leak of sodium ions (Na +), and conversely, anion exchange resin remaining in the cation exchange resin layer caused leakage of chlorine ions and sulfate ions (SO ₄ −).

Among these causes, sodium ions (Na +) or chlorine ions that enter the ion exchange resins whose surfaces are contaminated with iron oxide are not removed but remain inside the ion exchange resins, and they may leak by leaching to the surface of the ion exchange resins during the desalting process. In addition, when ammonia perfusion occurs by the ammonia injected to control the acidity (PH), sodium ions (Na +) are released. Most of the high pressure perfusion boilers of thermal power plants or boilers of pressurized water type nuclear power plants strictly regulate sodium and chlorine ions in the multi-processed water. Even if it is a multiple system, it is very serious and is not desirable at all.

As described above, in order to reduce ion leakage, especially sodium ion (Na ⁺ ) leakage, which is a major problem during operation of a multiple desalination plant, a new process is introduced over the multiple desalination method using the conventional resin separation method. Additional special desalination methods have emerged. That is, after completion of regeneration of the anion exchange resin by caustic soda, a small amount of cation exchange resin swept together with the anion exchange resin using 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 ions (Na ⁺ ), but could not completely remove sodium ions (Na ⁺ ).

Another method is to use sodium cation (Ca (OH) ₂ ) solution of high purity calcium hydroxide (Ca (OH) ₂ ) in the amount of cation exchange resin easily swept together with the anion exchange resin after regeneration of the caustic soda. There is a method of replacing the type cation exchange resin with a calcium (Ca ⁺⁺ ) type cation exchange resin, which may be present in the pipe and anion exchange resin after the injection of the calcium hydroxide (Ca (OH) ₂ ) solution is completed. In order to prevent the solidification of insoluble calcium hydroxide (Ca (OH) ₂ ) particles had to be thoroughly washed.

In addition, this method requires additional injection equipment and additional chemicals for the injection of calcium hydroxide (Ca (OH) ₂ ), which requires economical, high regeneration time, and requires caution in operation. As a chemical method for preventing ion leakage has the problems described above, in order to prevent the cation exchange resin from incorporating onto the anion exchange resin, it is equivalent to the middle of the specific gravity of the anion exchange resin and the specific gravity of the cation exchange resin. The idea of using some mediator to separate the resins has emerged.

That is, it is a rice method which performs multiple desalination using the method of floating-separating an anion exchange resin from a cation exchange resin using the liquid which has a special specific gravity corresponding to the middle of a cation exchange resin and an anion exchange resin.

This intermediate specific gravity solution is an 8-16% caustic soda solution, which is successful in separating an resin by forming an anion exchange resin layer on the top, a caustic soda solution on the middle, and a cation exchange resin layer on the bottom. This method, however, is inevitably 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 highly dynamic caustic soda solution and also requires a large amount of washing water. In addition, the regeneration process is complicated and has a drawback that takes a lot of regeneration time.

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 resin separation only After addition by using as a medium resin, backwashing is performed to form a heterogeneous resin state. In this state, a certain amount of anion exchange resin for the purpose of desalting is transferred to a separate tank 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 part thereof. Anion exchange resin and cation exchange resin are recovered again.

The mixed phase resin separation and the transfer of the intermediate medium resin according to the present invention are all made in one tower, and the tower stores the intermediate structure resin for the intermediate structure and resin separation for the purpose of separating the mixed phase resin and the cation exchange resin. It consists of two rooms of the undercarriage. In the case of the inert resin, the volume of the intermediate medium resin is preferably about 15% of the volume of the interphase resin for the purpose of the desalination function. On the other hand, in the case of active resins, about 20% of the volume of the mixed resin in the one-phase ion exchange resin tower for the purpose of desalting function is preferable, and the volume ratio of the cation exchange resin and the anion exchange resin is 1: 1 or desalination. It consists of the inverse of the volume ratio of the cation exchange resin and anion exchange resin of the intermodal 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 high precision 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 regenerant are provided. The conveying compressor and the like have not been shown to be on par with conventional methods known to date. This process diagram is a mixed phase ion exchange resin tower 1 representing a plurality of desalination processes, a separation tower and a cation regeneration tower for separating resin transferred from the mixed phase ion exchange resin tower 1 and regenerating a cation exchange resin (2). ), 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. It is composed of

On the other hand, the storage of the intermediate media resin (hereinafter referred to as intermediate resin) for the purpose of resin separation only is shown in the lower part of the separation column and the cation regeneration tower (2) for convenience in this process diagram, the position of the intermediate media resin reservoir (5) May be located in the anion regeneration tower 2 or the resin storage tower 4 according to the internal device design characteristics of each of the regeneration tower (2), (3) and the resin storage tower (4). In addition, the regenerated water introduced through the regeneration water inlet pipe 11 is used as flowing water, resin transfer water, backwash water, or resin mixed water according to the process, and the compressed air introduced through the compressed air inlet pipe 10 is used for resin mixing, Used for resin transfer.

FIG. 1 shows that the mixed phase ion exchange resin tower 1 which has lost the desalting function is waiting to stop operation and to be regenerated.

2, the intermediate resin (7) stored in the intermediate medium resin storage tank (5) before separating the mixed resin (6) that has lost the desalting function to the separation tower and cation regeneration tower (2) Shows the step of transferring to (2). The transfer of the intermediate resin 7 takes place in the following manner. That is, while supplying a sufficient and appropriate amount of compressed air and flowing water through the compressed air inlet valve (C-1) of the upper part of the tower and the inlet / outlet valve (C-2) of the lower part, the resin feed inlet valve (C-10) And C-11), the intermediate resin 7 is transferred from the intermediate medium resin reservoir 5 to the separation tower and the cation regeneration tower 2 through the resin inlet valve C-7. As the intermediate resin (7) is transferred, the air discharge valve (C-4) and the drain valve (C-15) 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 the 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 cation regeneration tower 2 through the resin outlet valve P-8. At the same time, the air discharge valve (C-4), the drain valve (C-15) and the resin inlet valve (C-6) of the separation column and the cation regeneration tower 2 are opened. After the transfer of most resin 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 inlet valve (P-3) to transfer the remaining resin remaining at the bottom of the tower. The process is completed by supplying air and resin transfer water.

4 shows a step 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 a cation exchange is formed to form a lower layer by flowing a flow rate capable of sufficiently floating the lighter anion exchange resin (8) onto 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 interphase resin by backwashing process is carried out through the following process. That is, the backwash water discharge valve C-17 is opened for the discharge of the backwash water while supplying the backwash water with a sufficient flow rate through the backwash port valve C-14.

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 a 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 part of the separation tower and the cation regeneration tower (2) through the inlet inlet valve (C-13), By supplying sufficient and appropriate extruded 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 the step of transferring the resin separation intermediate resin 7 from the separation column and the cation regeneration tower 2 to the intermediate medium resin storage tank 5 through the secondary resin transfer path. Before transporting the intermediate resin (7), the intermediate medium resin reservoir (5), the lower drainage valve (C-9) is opened and compressed through the compressed air inlet valve (C-3) above the separation column and the cation regeneration tower (2). After supplying air to pressurize the inside of the tank, resin feed water at an appropriate flow rate is supplied to the inlet / outlet valve (C-13).

At the same time, the resin outlet valve (C-8) is opened and the intermediate resin (7) is transferred from the separation column and the cation regeneration tower (2) to the intermediate medium resin reservoir (5).

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-15) and (C-16) 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 appropriate and sufficient compressed air through C-3), the resin conveying water and flowing water at an appropriate flow rate from the bottom of the tower are supplied through the resin conveying water inlet valve (C-2) and the inlet and outlet valve (C-13). It starts by At the same time, the cation exchange resin 9 is transported through the resin outlet valve (C-12) 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). Lose.

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 cation exchange resin with the pre-transfer completed. That is, firstly, the resin storage tower 4 opens the air discharge valve R-2 and the resin transfer discharge valve R-6 while the compressed air inlet valve A- over the anion regeneration tower 3 is opened. 1) Supplying compressed air through the resin, and supplying the resin conveying resin through the resin conveying inlet valve (A-6) at the bottom of the column, and at the same time, the resin outlet valve (A-7) and flowing water at the lower part of the anion regeneration tower 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. After the transfer of the anionic resin is completed, the resin mixture water and the resin mixing compressed air from the lower portion of the resin storage tower are mixed with the resin mixing inlet valve (R-7) and the compressed air inlet for mixing the resin. While supplying via the valve R-5, the air discharge valve R-2 and the drain valve R-9 are opened to mix the resin.

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 waiting for operation. In this process, the air discharge valve (R-2) and the flowing water and the resin transfer water discharge valve (P-6) of the upper portion of the mixed phase ion exchange resin tower (1) are opened, and are compressed in the upper portion of the resin storage tower (4). 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 of the column, 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 top 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 of treated water and increasing water volume.

Second, to prevent chemical destruction of the resin by cross-contamination and to minimize the contamination of the resin, to keep the durability of the resin longer and to maintain the ion exchange operation capacity of the resin 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.

Claims (12)

Intermediate resin for resin separation is used to separate the resin of the mixed phase resin which has lost its function in the regeneration type mixed bed type desalination facility of the tower, and separation tower and cation regeneration tower, anion regeneration tower, and resin storage for the use and recovery of the intermediate medium resin An ion exchange resin separation and desalination method comprising using a portion of a tower as an intermediate medium resin reservoir. The method of claim 1, wherein the intermediate resin in the intermediate resin storage tank is transferred to the separation column and the cation regeneration tower to separate the cation exchange resin and the anion exchange resin in a mixed phase which have lost function. The method according to claim 1, wherein an inert resin is used as the intermediate resin for resin separation. The method according to claim 1, wherein a predetermined amount of active resin composed of a cation exchange resin and an anion exchange resin is used as the intermediate resin for resin separation. The method of claim 1, wherein the anion exchange resin is transferred from the separation column and the cation regeneration tower to the anion regeneration column based on the intermediate resin. The method of claim 1 wherein the intermediate resin is recovered back into the intermediate resin reservoir. A method for purifying by passing a plurality of phases on a mixed resin composed of a cation exchange resin and an anion exchange resin recycled by using any one of claims 1 to 6. Intermediate resin for resin separation is used to separate the resin of the mixed phase resin which has lost its function in the regeneration type mixed bed type desalination facility of the tower, and separation tower and cation regeneration tower, anion regeneration tower, and resin storage for the use and recovery of the intermediate medium resin. An ion exchange resin separation and desalination apparatus comprising a portion of a tower as an intermediate medium resin storage tank. 10. The apparatus according to claim 8, wherein the intermediate resin in the intermediate resin reservoir is transferred to the cation regeneration tower for separation of the cation exchange resin and the anion exchange resin in the ineffective state. The device for transferring an anion exchange resin from a separation column and a cation regeneration tower to an anion regeneration tower based on the intermediate medium resin. 9. The apparatus of claim 8, wherein the intermediate resin is recovered back into the intermediate resin reservoir. 12. An apparatus for purifying a plurality of passages over a mixed resin state composed of a cation exchange resin and an anion exchange resin regenerated by using any one of claims 8 to 11.

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