JP6776926B2 - Ion exchange resin regeneration device and regeneration method - Google Patents

Description

The present invention relates to an ion exchange resin regenerator of a condensate desalination apparatus, and more particularly to an ion exchange resin regenerator for a condensate desalination apparatus in a thermal power plant, a nuclear power plant, or the like. The present invention also relates to an ion exchange method using this ion exchange device.

Usually, in the condensate desalting, a cation exchange resin regeneration tower, an anion exchange resin regeneration tower and a resin storage tank are installed for ion exchange resin regeneration, and the chemical solution regeneration is performed with sulfuric acid and caustic soda (for example, Patent Document 1). ..

The ion exchange regeneration apparatus and regeneration method described in Patent Document 1 will be described with reference to FIG. This regeneration device includes a condensate desalting tower 1, a cation exchange resin regeneration tower 3, an anion exchange resin regeneration tower 5, a resin storage tank 8, and pipes 2, 4, 6, 7 that connect these to enable resin transfer. 9 is an ion exchange resin regenerator in a condensate desalination apparatus using an outside tower regeneration method. The condensate desalting tower 1 is filled with a cation exchange resin and an anion exchange resin in a mixed state.

During normal operation, the pipes 2, 4, 6, 7, and 9 are stopped from flowing by closing the valves (not shown) provided in each pipe. The condensate treatment is performed by passing condensate through the condensate desalting tower 1 only through the pipes 10a and 10b. The ion exchange resin regeneration by this regeneration device is performed by the following resin removal / separation step, backwash regeneration step, and resin mixing / returning step.
<Resin removal / separation process>
(i) Stop the liquid flow through the pipes 10a and 10b, and disconnect the condensate desalting tower 1 from the main system.
(ii) The ion exchange resin in the condensate desalting tower 1 is transferred to the cation exchange resin regeneration tower 3 through the pipe 2.
(iii) Air is blown from the lower part (air scrubbing) in a state where the ion exchange resin is immersed in water in the cation exchange resin regeneration tower 3, and corrosion products (clad, etc.) adhering to the resin are desorbed.
(iv) By passing backwash water through the cation exchange resin regeneration tower 3 in an upward flow, the mixed ion exchange resin is separated into two upper and lower layers of the anion exchange resin and the cation exchange resin by the difference in specific gravity.
(v) The anion exchange resin is selectively extracted through the pipe 4 and transferred to the anion exchange resin regeneration tower 5.
<Backwash regeneration process>
(vi) Acids and alkalis are injected into the cation exchange resin regeneration tower 3 for the cation exchange resin and the anion exchange resin regeneration tower 5 for the anion exchange resin, respectively, to regenerate the chemical solution.
<Resin mixing / returning process>
(vii) After the chemical liquid regeneration is completed, the regenerated cation exchange resin and the anion exchange resin are transferred to the resin storage tank 8 through the pipes 6 and 7, respectively.
(viii) Cleaning and mixing operations are performed in the resin storage tank 8.
(ix) The ion exchange resin in the resin storage tank 8 is returned to the condensate desalting tower 1 through the pipe 9 in a mixed state.
(x) The flow of the pipe 9 is stopped, and the condensate desalting tower 1 is put into a standby state as a spare tower.

As a result, the regeneration is completed, so that the condensate flow is restarted via the pipes 10a and 10b, and the desalination treatment operation is returned.

In this regeneration method, since the cation exchange resin regeneration tower 3 is emptied in the step (vii) and almost all the water is drained from the inside of the pipe 4, even if the valve of the pipe 4 is closed. In the step (ii) of the regeneration step of the next turn, the ion exchange resin easily enters the pipe 4. That is, when the ion exchange resin is received from the condensate desalting tower 1 into the cation exchange resin regeneration tower 3, even if the valve of the pipe 4 is closed, the resin is discharged due to the vigorous flow of the resin due to the water flow at the time of receiving the ion exchange resin. The ion exchange resin easily enters the head portion and the transfer pipe 4. If step (iv) is performed in this state, the cation exchange resin and the anion exchange resin in the ion exchange resin mixed in the pipe 4 are not separated. Therefore, in the step (v), the ion exchange resin containing the cation exchange resin in the pipe 4 is mixed in the anion exchange resin regeneration tower 5, and the cation exchange resin is reversely regenerated in the step (vi). As a result, the utilization efficiency of the cation exchange resin is lowered.

Japanese Unexamined Patent Publication No. 55-051445

The present invention prevents the cation exchange resin from being mixed into the anion exchange resin regeneration tower, thereby preventing the reverse regeneration of the cation exchange resin and improving the utilization efficiency of the ion exchange resin. The ion exchange resin in the condensate desalination apparatus. An object of the present invention is to provide a regenerating device and an ion exchange regeneration method using the regenerating device.

In the ion exchange resin regeneration apparatus of the present invention, the ion exchange resin regeneration tower, the cation exchange resin regeneration tower, the anion exchange resin regeneration tower, and the resin storage tank are connected by a pipe so that the resin can be transferred. In the exchange resin recycling apparatus, an on-off valve is provided in the resin transfer pipe connecting the ion exchange resin discharge port provided in the middle of the cation exchange resin regeneration tower in the vertical direction and the anion exchange resin regeneration tower, and the resin transfer pipe is provided. Of these, a return water supply pipe for returning the ion exchange resin mixed in the resin transfer pipe to the cation exchange resin regeneration tower is connected to the upstream side of the on-off valve.

The ion exchange resin regeneration method of the present invention is an ion exchange resin regeneration method using the ion exchange resin regeneration apparatus of the present invention, and transfers the ion exchange resin in the condensate desalting tower to the cation exchange resin regeneration tower. A first resin that supplies backwash water from the lower part of the cation exchange resin regeneration tower and separates the cation exchange resin and the anion exchange resin by the difference in specific gravity until the separation interface is below the resin discharge port. After the separation step and the first resin separation step, a return step of inflowing return water to the upstream side of the on-off valve of the resin transfer pipe to return the ion exchange resin in the transfer pipe to the cation exchange resin regeneration tower. After the return step, a second resin separation step of supplying backwash water from the lower part of the cation exchange resin regeneration tower to separate the cation exchange resin and the anion exchange resin by a specific gravity difference, and the second resin separation. After the step, an anion exchange resin discharge step of transferring the anion exchange resin from the inside of the cation exchange resin regeneration tower to the anion exchange resin regeneration tower through a resin transfer pipe, and a cation exchange resin regeneration in the cation exchange resin regeneration tower are performed. It includes a regeneration step of regenerating the anion exchange resin in the anion exchange resin regeneration tower and a step of transferring the regenerated cation exchange resin and the anion exchange resin to the resin storage tank.

One aspect of the ion exchange resin regeneration method of the present invention is a mixed layer of an anion exchange resin and a cation exchange resin existing above the cation exchange resin layer in the cation exchange resin regeneration tower after the second resin separation step. Has a mixed layer transfer step of transferring the resin to the resin storage tank.

In the present invention, the ion exchange resin has entered the anion exchange resin transfer pipe in the ion exchange resin transfer from the condensate desalting tower to the cation exchange resin regeneration tower and the subsequent first separation step, and the ion exchange resin contains the ion exchange resin. Ion exchange resin is mixed. Therefore, water is supplied into the anion exchange resin transfer pipe to return the ion exchange resin to the cation exchange resin regeneration tower. After that, the second separation step is performed. Then, substantially only the anion exchange resin enters the anion exchange resin transfer pipe. Therefore, when the anion exchange resin in the cation exchange resin regeneration tower is subsequently transferred to the anion exchange resin regeneration tower, the transferred anion exchange resin is hardly mixed with the cation exchange resin. This makes it possible to prevent the cation exchange resin from being mixed into the anion exchange resin regeneration tower.

After transferring the anion exchange resin from the cation exchange resin regeneration tower, the mixed layer (mixture layer of the cation exchange resin and the anion exchange resin) above the cation exchange resin layer of the cation exchange resin regeneration tower is transferred to the resin storage tank. , The anion exchange resin in the mixed layer is prevented from being reversely regenerated in the cation exchange resin regeneration tower.

It is a system diagram of the ion exchange resin regeneration apparatus which concerns on embodiment. It is a system diagram of the ion exchange resin regeneration apparatus which concerns on a conventional example. It is explanatory drawing of the resin separation step in the cation exchange resin regeneration tower in embodiment.

Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 shows an ion exchange resin regenerating device according to an embodiment, and members common to the ion exchange resin regenerating device of FIG. 2 are designated by the same reference numerals.

A backwash water supply pipe 11 having a valve 11a is connected to the bottom of the cation exchange resin regeneration tower 3, and a backwash drainage drainage pipe 12 having a valve 12a is connected to the top. As schematically shown in FIG. 3, an anion exchange resin discharge port 4a is installed in the middle of the cation exchange resin regeneration tower 3 in the vertical direction, and the upstream end of the resin transfer pipe 4 is the anion exchange resin discharge port 4a. It is connected to the.

A valve 15 is provided in the middle of the resin transfer pipe 4. The ion exchange resin (cation exchange resin and anion exchange resin) in the pipe 4 flows through the cation exchange resin regeneration tower 3 on the upstream side (cation exchange resin regeneration tower 3 side) of the resin transfer pipe 4 from the valve 15. A return water supply pipe 14 for discharging is connected. A valve 14a is provided in the pipe 14.

The resin transfer pipe 17 branches from between the connection portion of the water supply pipe 14 and the valve 15 of the resin transfer pipe 4, and the end (downstream end) of the resin transfer pipe 17 is located above the resin storage tank 8. It is connected. A valve 17a is provided in the resin transfer pipe 17. The valve 17a is located in the immediate vicinity of the upstream end of the pipe 17.

Other configurations of this anion exchange resin device are the same as those of the ion exchange resin regeneration device of FIG.

This ion exchange resin regenerating device is operated by the following resin removing / separating step, regenerating step, and resin mixing / returning step.

<Resin removal / separation process>
(1) Stop the liquid flow of the pipes 10a and 10b, and disconnect the condensate desalting tower 1 from the main system.
(2) The valve (not shown) provided in the pipe 2 is opened, and the ion exchange water is supplied into the condensate desalting tower 1 to supply the ion exchange resin (cation exchange resin) in the condensate desalting tower 1. And the ion exchange resin) is transferred to the cation exchange resin regeneration tower 3 through the pipe 2 (FIG. 3 (a)).

(3) First separation step: The valves 11a and 12a are opened, the valves 14a, 15 and 17a are closed, and the backwash water is poured into the cation exchange resin regeneration tower 3 preferably at LV5 to 15 m / hr for 5 minutes or more. By flowing water in the direction, the mixed ion exchange resin in the regeneration tower 3 is separated into two upper and lower layers of the anion exchange resin and the cation exchange resin by a difference in specific gravity. This step is performed at least until the resin separation interface is lower than the anion exchange resin discharge port 4a (FIG. 3 (b)).
In this step (3), it may be detected by the resin sensor that the resin separation interface is lower than the resin discharge port 4a, but it may be a cation exchange resin regeneration tower having a normal resin discharge port height. For example, the resin separation interface becomes lower than the resin discharge port 4a by performing backwash water flow at a small LV (for example, 5 to 15 m / hr) for 5 minutes or more, so that water can be detected by passing water under these water flow conditions. -It is also possible to omit the judgment.

(4) Return step: The valves 12a and 14a are opened, the valves 15 and 17a are closed, the return water is supplied from the pipe 14 into the resin transfer pipe 4, and the water enters the pipe 4 and the anion exchange resin discharge port 4a. The ion exchange resin (cation exchange resin and anion exchange resin) that has been left is returned to the cation exchange resin regeneration tower 3. This return step is preferably performed for 10 seconds or longer. In this return step, the valve 11a may be opened or closed.

(5) Second separation step: The valves 11a and 12a are opened, the valves 14a, 15 and 17a are closed, and the backwash water in the cation exchange resin regeneration tower 3 is preferably upward at LV5 to 15 m / hr for 10 minutes or more. After flowing water, the difference in specific gravity between the anion exchange resin and the cation exchange resin is separated again in the cation exchange resin regeneration tower 3. The resin that enters the pipe 4 from the anion exchange resin discharge port 4a during this second separation step is an anion exchange resin. This second separation step is performed until the resin interface becomes almost constant.

(6) Anion exchange resin extraction step: The valves 11a and 15 are opened, the valves 12a, 14a and 17a are closed, and the anion exchange resin on the upper layer side in the cation exchange resin regeneration tower 3 is used as the anion exchange resin discharge port 4a and. It is pulled out through the resin transfer pipe 4 and transferred to the anion exchange resin regeneration tower 5 (FIG. 3 (c)). As described above, since only the anion exchange resin remains substantially in the pipe 4, the anion exchange resin transferred to the anion exchange resin regeneration tower 5 is hardly mixed with the cation exchange resin. Therefore, in the subsequent regeneration step, the cation exchange resin is prevented from being reversely regenerated in the anion exchange resin regeneration tower 5.

(7) Mixed layer extraction step: When the anion exchange resin is discharged and transferred to the level of the anion exchange resin discharge port 4a, as shown in FIG. 3C, the anion exchange resin discharge port 4a and the upper surface of the cation exchange resin layer A mixed layer of the anion exchange resin and the cation exchange resin remains between them.
Therefore, the valves 11a and 12a are opened, the valves 14a, 15 and 17a are closed, and the backwash is performed by accelerating the LV to flow upward (for example, LV10 to 20 m / hr), and the mixed layer and the cation are performed. The opening of the valve 11a is adjusted so that the interface with the exchange resin layer is pushed up and further resin separation is promoted in the mixed layer (Fig. 3 (d)), and this interface is lowered to the vicinity of the anion exchange resin discharge port 4a (Fig. 3). 3 (e)), then the valve 12a is closed, the valve 17a is opened, and the mixed resin of the anion exchange resin and the cation exchange resin constituting the mixed layer is introduced into the anion exchange resin discharge port 4a and the pipe 4 (branch of the pipe 17). (Upstream side from the section) and transferred to the resin storage tank 8 via the pipe 17 (FIG. 3 (f)).

This prevents the anion exchange resin from remaining in the cation exchange resin in the cation exchange resin regeneration tower 3. Therefore, in the next regeneration step, the anion exchange resin is prevented from being reversely regenerated in the cation exchange resin regeneration tower 3.

<Regeneration process>
(8) In each of the cation exchange resin regeneration tower 3 and the anion exchange resin regeneration tower 5, air is blown from the lower part (air scrubbing) while the resin is immersed in water to remove corrosion products (clad, etc.) adhering to the resin. Detach.
(9) Acid is injected into the cation exchange resin regeneration tower 3 from the pipe 13 to regenerate the cation exchange resin. Further, alkali is injected into the anion exchange resin regeneration tower 5 from the pipe 16 to regenerate the anion exchange resin.

<Resin mixing / returning process>
(10) After the regeneration of the cation exchange resin and the anion exchange resin is completed, the regenerated cation exchange resin and the anion exchange resin are transferred to the resin storage tank 8 through the pipes 6 and 7, respectively.
(11) Cleaning and mixing operations are performed in the resin storage tank 8.
(12) The ion exchange resin in the resin storage tank 8 is returned to the condensate desalting tower 1 through the pipe 9 in a mixed state.
(13) The liquid flow of the pipe 9 is stopped, the condensate water flow of the pipes 10a and 10b is restarted, and the normal desalination treatment operation is returned.

The above description is an example of the present invention, and the present invention may be in a form other than the above. For example, after the anion exchange resin extraction step of (6), a third separation step may be performed, then the anion exchange resin may be extracted if necessary, and then the mixed layer extraction step of (7) may be performed. Further, air scrubbing may be performed at the same timing as the conventional example of FIG.

[Example 1]
In the ion exchange resin regeneration apparatus having the configuration shown in FIG. 1, the anion exchange resin discharge port 4a was arranged at a position at a height of 1600 mm from the lower water collecting plate in the cation exchange resin regeneration tower (inner diameter 1700 mm, tower height 4100 mm) 3. The following ions were used as the ion exchange resin.

Cation exchange resin: Diaion UBk14HK
Anion exchange resin: Diaion PA312LOH

The cation exchange resin 2800L and the anion exchange resin 1300L were housed in the cation exchange resin regeneration tower 3 in a mixed state. Then, of the above steps (1) to (13), steps (3) to (7) were performed under the following conditions. Then, the amount of the cation exchange resin mixed in the anion exchange resin separated from the cation exchange resin regeneration tower and extracted was calculated as the cation exchange resin mixing ratio (volume%), and the effect was verified. The results are shown in Table 1.

(3) First separation step: LV10 m / hr x 8 minutes (4) Return step: Return water amount 335 L / min x 2 minutes (LV10 m / hr)
(5) Second separation step: LV10 m / hr × 35 minutes (6) Anion exchange resin extraction step: LV10 m / hr × 10 minutes (7) Mixed layer extraction step: LV15 m / hr × (backwash 25 minutes + extraction) 20 minutes out)

In addition, the thickness of the mixed layer extracted by the mixed layer extraction step of (7) was measured and shown in Table 1.

[Examples 2 and 3]
Examples except that the mixed layer extraction step was performed so that the thickness of the mixed layer extracted by the mixed layer extraction step of the step (7) was 100 mm (Example 2) or 50 mm (Example 3). The same operation as in 1 was performed. Table 1 shows the measurement results of the cation exchange resin mixing ratio and the extracted mixed layer thickness.

[Comparative Example 1]
The same operation as in Example 1 was performed except that the return step of (4) was not performed. Table 1 shows the measurement results of the cation exchange resin mixing ratio and the extracted mixed layer thickness.

From Table 1, it was confirmed that the cation exchange resin mixing rate was lower than that of Comparative Example 1 by performing the return step of returning the ion exchange resin that had entered the anion exchange resin transfer pipe to the cation exchange resin regeneration tower.

Further, as in Examples 1 and 2, it was confirmed that the cation exchange resin mixing rate was lower than that in Example 3 by setting the extraction thickness of the mixed layer to 100 mm or more.

1 Condensate desalination tower 3 Cationic exchange resin regeneration tower 4 Anion exchange resin transfer pipe 4a Anion exchange resin discharge port (discharge head)
5 Anion exchange resin regeneration tower 8 Resin storage tank 14 Return water supply piping

Claims (3)

In the ion exchange resin regeneration apparatus for desalination, in which the condensate desalting tower, the cation exchange resin reclaiming tower, the anion exchange resin regenerating tower, and the resin storage tank are connected by piping so that the resin can be transferred.
An on-off valve is provided in the resin transfer pipe connecting the ion exchange resin discharge port provided in the vertical direction of the cation exchange resin reclaiming tower and the anion exchange resin regenerating tower, and the on-off valve of the resin transfer pipe is used. An ion exchange resin regenerating device characterized in that a return water supply pipe for returning the ion exchange resin mixed in the resin transfer pipe to the cation exchange resin regenerating tower is connected to the upstream side. A method for regenerating an ion exchange resin using the ion exchange resin regenerating device according to claim 1.
The step of transferring the ion exchange resin in the condensate desalting tower to the cation exchange resin regeneration tower, and
A first resin separation step in which backwash water is supplied from the lower part of the cation exchange resin regeneration tower, and the cation exchange resin and the anion exchange resin are separated by a difference in specific gravity until the separation interface is below the resin discharge port. ,
After the first resin separation step, a return step of inflowing return water to the upstream side of the on-off valve of the resin transfer pipe and returning the ion exchange resin in the transfer pipe to the cation exchange resin regeneration tower,
After the return step, a second resin separation step of supplying backwash water from the lower part of the cation exchange resin regeneration tower to separate the cation exchange resin and the anion exchange resin by a specific gravity difference, and
After the second resin separation step, an anion exchange resin discharge step of transferring the anion exchange resin from the inside of the cation exchange resin regeneration tower to the anion exchange resin regeneration tower through a resin transfer pipe, and
A regeneration step of regenerating the cation exchange resin in the cation exchange resin regeneration tower and regenerating the anion exchange resin in the anion exchange resin regeneration tower.
The step of transferring the regenerated cation exchange resin and the anion exchange resin to the resin storage tank, and
A method for regenerating an ion exchange resin, which comprises. In claim 2, after the second resin separation step, a mixed layer of anion exchange resin and cation exchange resin existing above the cation exchange resin layer in the cation exchange resin regeneration tower is transferred to the resin storage tank. An ion exchange resin regeneration method characterized by having a layer transfer step.

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