JPH05154474A - Condensate desalter - Google Patents

Abstract

PURPOSE:To obtain sufficient mixed conditions of resin without performing mixing operation in a desalter by only returning and transferring regenerated resin in the mixed conditions from resin regenerating equipment to a mixed bed type condensate desalter installed in a condensate treating system in a power plant. CONSTITUTION:A regenerated resin returning pipe 17 provided for letting a desalter 40 receive ion exchange resin made in mixed conditions by regenerating equipment and a entrained water adjusting device 41 near the connected part of the returning pipe 17 connected to the condensate desalter 40 are provided. By letting the returned resin slurry flow on a screen in the adjusting device 41, the quantity of entrained water is decreased to the appropriate one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condensate demineralizer used in a condensate treatment system in a power plant such as a thermal power plant or a nuclear power plant.

[0002]

Description of the Related Art A thermal power plant will be described as an example. In a power plant, steam generated by a boiler is used to drive a turbine, which is cooled by heat exchange to be condensed water and supplied to the boiler again. Although a condensate circulation system is installed, a filter and a desalting tower for removing ions are provided in the condensate circulation system for the purpose of removing impurities contained in the condensate. Here, the desalting tower provided in the condensate circulation system for treating the condensate constitutes a condensate desalination apparatus together with a regeneration facility outside the circulation system for regenerating and reusing the ion exchange resin used, In general, it is composed of a plurality of demineralization towers and a series of regeneration equipment connected in parallel to them.

The structure of an example of such condensate treatment and the outline of its operation will be further explained. Normally, in the condensate circulation system, condensate is treated by a plurality of desalting towers, and one of the towers is treated. When the pressure loss increases or the fixed yield is reached, the ion-exchange resin (that is, the used resin) in the demineralization tower is transferred to the regenerator and at the same time regenerated and stored in the regenerator. The regenerated resin is charged in the desalting tower to restart water flow. Further, the resin transferred to the recycling facility is recycled according to a predetermined procedure, and is prepared for the next exchange with the used resin. Regeneration equipment used in the condensate demineralizer and its operation include cation exchange resin (CER) and anion exchange resin (AE).
There are various methods such as a method of regenerating R) in separate towers and a method of regenerating in one tower.

In the condensate demineralization tower, it is required to use an anion exchange resin and a cation exchange resin in a uniform mixture. As a method for performing this mixing operation, the anion exchange resin and the cation exchange resin are used in the regeneration tower. There are known a method in which the resin is mixed and then filled (returned) in the desalting tower, and a method in which both ion exchange resins are mixed in the desalting tower.

However, each of these methods has the following problems. For example, in the latter method, the mixed resin returned to the desalting tower is subjected to air mixing (several minutes) in a state of being filled with water to a certain height above the resin layer. In this case, a good mixed state of both resins can be obtained during air mixing, but it is difficult to avoid the phenomenon of specific gravity separation when the resins are allowed to settle after mixing. In order to reduce the effect, the blow valve is opened immediately after air mixing, and at the same time, a large amount of water is passed downward from the upper part of the desalting tower, but this is not sufficient. The effect of this specific gravity separation appears as a problem that the anion exchange resin mixing ratio is insufficient in the lower part of the mixed resin layer.As a result, for example, after periodic inspections of power plant equipment, auxiliary materials such as rust preventives and anti-seizure agents are removed. Anion exchange resin may be contaminated when brought into a salt tower, and the capacity of the anion exchange resin may be deteriorated. It is sufficient if the deterioration of capacity due to contamination can be eliminated by a normal regeneration treatment. When a resin is used, some of the Cl ⁻ (or SO ₄ ⁻ ) etc. leaking out from the cation exchange resin below the mixed resin layer is poorly captured by the anion exchange resin, resulting in deterioration of treated water quality.

In addition, since the mixed resin is returned to the desalting tower in the regeneration equipment, the mixing operation is performed again, so that there are many time and equipment losses.

On the other hand, the method of returning the mixed resin in the above-mentioned regeneration equipment to the desalting tower as it is in a mixed state is advantageous because it is possible to transfer the premixed resin to the desalting tower, but it is possible to entrain water. The resin entrained water was excessive because it passed through the return pipe at a high linear velocity, and when it was introduced into the desalting tower, the resin around the outlet was disturbed by a large amount of water, and the resin separated as it moved away from the outlet. Will occur. Therefore, even in this method, there is a drawback in that the mixing ratio of the anion exchange resin in the lower portion of the mixed resin layer becomes insufficient.

[0008]

DISCLOSURE OF THE INVENTION The inventor of the present invention proposes the present invention by making intensive studies for the purpose of solving the problems of the prior art in the condensate demineralizer as described above.

That is, the object of the present invention is to utilize the advantage of the system of returning the mixed resin from the regeneration equipment to the desalting tower by using excess entrained water (the remixing operation in the desalting tower is unnecessary), and With the adoption of a mixed resin return method that does not cause operational time loss and equipment loss, it is ideal without exhibiting the mixing disproportionality due to the specific gravity separation of both resins, which is a drawback of the conventional method. An object of the present invention is to provide a condensate demineralizer that can ensure a state close to a uniform homogeneous mixed state.

Another object of the present invention is to ensure a uniform mixed state of the cation exchange resin and the anion exchange resin in the condensate demineralization tower, whereby a condensate having excellent treated water quality can be obtained. It is the place to provide the equipment that can maintain the water desalination tower.

Still another object of the present invention is to provide a condensate demineralizer which does not require re-mixing in the desalting tower and therefore does not require auxiliary equipment and has a short regeneration time. ..

Another object of the present invention is to provide an apparatus capable of removing the ion exchange resin, which has been atomized or crushed over time and atomized, to the outside of the system while achieving the above object. It is in.

[0013]

In order to achieve the above object, the present inventor has completed the present invention described in each claim of the above-mentioned claims.

The condensate demineralizer of the present invention is typically a mixed bed type condensate demineralizer provided in the condensate treatment system of a power plant, and the condensate demineralizer taken out from the condensate demineralizer. And a regeneration equipment for regenerating the ion exchange resin, a take-out transfer pipe of the resin piped to take out the ion exchange resin from the condensate demineralization tower and transfer it to the regeneration equipment, and a mixed state in the regeneration equipment. Condensed water for returning the regenerated resin to the condensate demineralization tower by accommodating water through this return pipe In the desalination apparatus, a configuration in which an entrained water amount adjusting means for reducing the amount of resin-entrained water in the return pipe is provided near the connection portion of the return pipe connected to the condensate demineralization tower to the condensate demineralization tower It is characterized by having.

The entrained water amount adjusting means is composed of, for example, a screen and a means for flowing a slurry containing regenerated resin and entrained water onto the screen. As the screen, in particular, a large number of metal plates and synthetic resins are used. A plate formed by arranging plates in parallel in the thickness direction with a minute gap therebetween can be preferably used. As this screen, for example, a plate provided with a large number of small projections is fitted into and suspended from a common suspension rod, and a large number of such plates are stacked so that the small projections serve as spacers. It is possible to form a screen in which the opening size is accurately set by adopting the one that is pressed from both ends. In addition, this allows the ion exchange resin to be crushed by setting the opening size as large as possible (eg, 0.25 to 0.30 mm) within a range that does not allow the ion exchange resin with a lower limit particle size when new. There is an advantage that the ion exchange resin, which has been atomized by the above method, can be dropped under the screen to obtain the action of removing it to the outside of the system.

By using the entrained water amount adjusting means as described above, it is possible to smoothly transfer the mixed resin with excess entrained water in the return pipe on the upstream side (regeneration facility side), while the entrained water amount adjusting Downstream of means (demineralization tower side)
Then, the degree of entrained water (preferably 0.6 to 0.7 times the resin) can be adjusted so as to reduce the occurrence of the separation phenomenon of the mixed resin in the desalting tower.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below based on the embodiments shown in the drawings. FIG. 3 shows an outline of the configuration of a condensate desalination apparatus to which the present invention is applied. In this figure, only one desalting tower 40 is shown for convenience of regeneration equipment 30. .. The illustration of the condensate circulation system provided with the desalting tower 40 is omitted.

The structure and operation of the regeneration equipment 30 are as follows. That is, 1 is a separation and cation exchange resin regeneration tower, 2 is a mixed resin receiving tank, 3 is an anion exchange resin regeneration tower, and the used mixed resin transferred from the desalting tower 40 through the resin transfer pipe 5, Mixed resin receiving tank 2 described later
Used mixed resin 2 transferred from inside via transfer pipe 21
0 is received in the separation and cation exchange resin regeneration tower 1,
After sufficiently scrubbing with air or the like and discharging the clad such as iron oxide to the outside with a water flow, an upward flow of backwash water is caused to flow from the lower part of the regeneration tower 1 to sufficiently expand both ion-exchange resins and By utilizing the difference in the sedimentation rate of the exchange resin, the cation exchange resin is collected in the lower layer, the anion exchange resin is collected in the upper layer, and then the inflow of backwash water is stopped to allow the cation exchange resin to settle. An anion exchange resin layer 7 is formed on the upper layer.

Then, a small amount of the anion exchange resin 7a (shown by hatching in the figure) above the separation boundary surface 8 of both ion exchange resins is left, and most of the other anion exchange resin 7 is transferred through the resin transfer pipe 9. Transferred to the anion exchange resin regeneration tower 3, and then a small amount of the remaining anion exchange resin 7a,
A small amount of cation exchange resin 6a below the separation boundary surface 8
And (indicated by diagonal lines) are transferred to the mixed resin receiving tank 2 using the resin transfer pipe 10. After such transfer is completed,
In the separation / cation exchange resin regeneration tower 1, the acid regeneration agent is passed from the outside through the acid regeneration agent passage pipe 11 and the distributor 12, and then extruded and washed to regenerate the cation exchange resin 6 by a conventional method. ..

On the other hand, also in the anion exchange resin regeneration tower 3, the alkali regenerant feed pipe 13 and the distributor 14 are used.
An alkali regenerant is passed from the outside through the above, and then extruded and washed to regenerate the anion exchange resin 7 by a conventional method.

After the above regeneration is completed, the regenerated cation exchange resin 6 in the separation / cation exchange resin regeneration tower 1 is transferred to the resin storage tank 4 via the resin transfer pipe 15, and the anion exchange resin regeneration tower 3 The regenerated anion exchange resin 7 therein is transferred to the resin storage tank 4 through the resin transfer pipe 16, and after the transfer, both ion exchange resins are sufficiently mixed and stored as a regenerated mixed resin. The stored mixed resin in the resin storage tank 4 is transferred (returned) to the desalting tower 40 (actually, a desalting tower different from the one shown in the figure) via the resin returning pipe 17 when necessary.

Next, a detailed structure for receiving the returned mixed resin into the desalting tower 40, which is a characteristic part of the present embodiment of the condensate demineralizer having the structure described in FIG. 3, will be described. ..

FIG. 1 shows an outline of the structure of the demineralization tower 40. The demineralization tower 40 is provided in a condensate circulation system of, for example, a thermal power plant, not shown, and a condenser is also provided from a boiler (not shown). The condensate thus formed is passed through the condensate inlet pipe 43 from the upper distributor 44 to the inside of the tower, and passes through the mixed resin layer filled inside to collect water in the lower collector collector 4
5, 45, ... Passes through the outlet pipe 46 and is again sent to the boiler.

As described above, the mixed resin in the desalting tower 40 is used for a predetermined period of time and then transferred to the above-mentioned regeneration equipment to be subjected to a regeneration treatment. In the tower 40, the slurry 47 of the regenerated mixed resin (second
(See the drawing) is returned through the return pipe 17.

The feature of this example is that an entrained water amount adjusting device 41 is provided in the vicinity of the connection portion of the return pipe 17 to the desalting tower 40, and the entrained water is reduced through the entrained water amount adjusting device 41. Resin slurry 48 (eg, 0.6 for resin
The amount of entrained water (about 0.7 times the amount) is filled in the desalination tower 40 from the resin filling nozzle 42.

The entrained water amount adjusting device 41 of the present embodiment is the second
As shown in the figure, a screen 413 is installed obliquely (20 to 35 °) in a box-shaped container sealed from the outside, and a mixed resin slurry introduction pipe 411 (extending portion of the return pipe 17) is provided. The opening 412 is provided so as to face the screen 413 substantially horizontally. This is because good drainage can be obtained as compared with the system in which the slurry 47 is simply allowed to flow down on the screen. The water that has passed through the screen 413 is sent to an appropriate drainage device through the drainage pipe 414, but may be reused after passing through a filter or the like. The slurry 48, which has flowed on the screen 413 and whose amount of entrained water has been reduced, is filled from the resin filling nozzle 42 into the desalting tower 40 through the resin supply chute 415.

Of course, the present invention is not limited to the above-mentioned examples, and is not limited to, for example, a method of reusing a used resin, and a resin regenerated by any known regeneration method is removed. The present invention can be applied to the case of returning to the salt tower. Further, the entrained water amount adjusting device is not limited to the one having the above configuration. For example, it is particularly preferable to use a corrosion-resistant stainless steel plate material to form a large number of small protrusions of about 0.3 mm by a press or the like, and stack a large number of these in the thickness direction to form a screen. According to such a configuration, for example, a large number of these stainless steel plate members are fitted and hung by a common suspension rod (for example, two parallel rods), and the laminated body is loosened and pressed from both sides. By providing such a state that it can be switched between the above states, it is possible to use it as a screen in a pressured state at the time of use, and to release the pressure at the time of clogged cleaning to facilitate cleaning. In addition, this method not only facilitates the cleaning operation to clear the clogging, but also sets the size of the small protrusions precisely to precisely determine the opening size of the screen. The ion exchange resin with a uniform particle size will not pass through, but the resin that has become smaller than this over time will be passed through and the worn or crushed resin will be removed and discharged through this screen. There is an advantage that is possible. Such a resin having a small particle size causes an increase in pressure loss of the desalting tower, a problem that the ion exchange performance is not properly exhibited, and is unevenly distributed during settling in the desalting tower or in the regeneration storage tank. Since there is a tendency that there is a tendency, the effect of removal thereof is extremely large.

Test Example 1 Using the apparatus shown in FIGS. 1 and 2, the desalting tower was filled with the mixed resin. The test conditions are as shown in Table 1 below, and the mixing state of the resin in the desalting tower at that time was examined and shown in Table 3. The anion exchange resin mixing ratio of the mixed resin layer was measured according to the following method.

First, water is once drained from the resin tower which has been filled with the resin after the resin transfer is completed, and the manhole attached to the upper part of the resin tower is opened. Next, from the lower part of the resin tower, ascending flow of water having a slow flow rate (LV = 1 m / H) to such an extent that the mixed resin in the tower is not separated, and when the water reaches the upper part of the resin layer, From the manhole, 400m from the center of the resin tower and from the center
Sampling pipes made of hard vinyl chloride having a diameter of 1 inch and a length of 1.5 m are vertically inserted into the resin layers at positions separated by m and 800 mm, respectively. By inserting each sampling pipe to the lower portion of the resin layer, the ion exchange resin is introduced into each sampling pipe while maintaining the initial filled state.

Then, the flow of water into the tower is stopped, and thereafter, all the water in the tower is drained.

When the drainage is completed, the sampling pipes are carefully extracted from the resin layer, and then the sampling pipes are cut from the lower end at regular intervals of 200 mm.

The ion exchange resin in each pipe cut to 200 mm was taken out and put in a graduated cylinder, saturated saline was added to this, and the mixture was stirred to separate the cation exchange resin and the anion exchange resin by the difference in specific gravity. Then, the amount of each resin was measured to obtain the mixing ratio.

[0033]

[Table 1]

[0034]

[Table 2]

As can be seen from these results, the mixed resin layer in the desalting tower is filled at a height of every 200 mm from the lower portion of the resin layer, and moreover from the center to the peripheral portion in a state close to the ideal value. It is confirmed that the quality of treated water is significantly improved as compared with the conventional method.

Comparative Test Example 1 For comparison, a mixing operation in which the desalting tower was filled with the mixed resin by a conventional method and then air was passed under the conditions shown in Table 3 below, and the mixing state of the resin in the desalting tower at that time was performed. Was examined in the same manner as in Test Example 1, and the results are shown in Table 4 below.

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

According to the apparatus of the present invention, since the system for returning the mixed resin regenerating facility to the desalting tower by using the excess entrained water is adopted, the remixing operation in the desalting tower is unnecessary. It has the advantage that there is no time loss and no equipment loss,
In addition, since the amount of water entrained in the mixed resin that is received in the desalting tower is adjusted, the ideal homogeneous mixed state can be achieved without exhibiting the mixing disproportion due to the specific gravity separation of both resins, which was a drawback of the conventional method. There is an effect that a state close to can be secured.

Further, since a uniform mixed state of the cation exchange resin and the anion exchange resin can be secured in the condensate demineralization tower,
There is an effect that condensate with excellent treated water quality can be obtained.

Furthermore, since there is no need for re-mixing in the desalting tower, there is an effect that a condensate demineralizer can be provided which requires no additional equipment and has a short regeneration time.

Furthermore, according to the apparatus of the present invention, not only the above-mentioned various objects can be achieved, but also the ion exchange resin which has been atomized or crushed over time to be atomized can be easily removed from the system by using a screen. There is also an effect that it can be removed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a schematic configuration of a demineralization tower of a condensate demineralizer provided by the present invention.

FIG. 2 (a) is a schematic front view of an entrained water amount adjusting device used in the same device, and FIG. 2 (b) is a side outline view of the entrained water amount adjusting device.

FIG. 3 is a diagram showing an example of a schematic configuration of a regenerating facility of a condensate demineralizer to which the device of the present invention is applied.

[Explanation of symbols]

40 ... Desalination tower, 41 ... Entrained water amount adjusting device, 42
... Mixed resin filling nozzle, 43 ... Condensate inlet pipe, 4
4 ... Distributor, 45 ... Water collection collector, 46 ... Exit pipe, 47 ... Slurry, 48 ...
-Resin slurry, 411 ... Mixed resin slurry introduction pipe, 412 ... Opening, 413 ... Screen, 41
4 ... Drain pipe, 415 ... Resin supply chute, 1 ...
..Separation and cation exchange resin regeneration tower, 2 ... Mixed resin receiving tower, 3 ... Anion exchange resin regeneration tower, 4 ...
Resin storage tank, 5 ... Resin transfer pipe, 17 ... Resin return pipe.

[Procedure amendment]

[Submission date] November 11, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

[0037]

[Table 3]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

Further, according to the apparatus of the present invention, not only the above-mentioned various objects can be achieved, but also the ion exchange resin which is worn or crushed with time to be atomized can be easily removed from the system by using a screen. There is also an effect that can be removed.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG. 1 is a diagram showing an example of a schematic configuration of a desalination tower of a condensate demineralizer to which the present invention is applied .

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (6)

[Claims] 1. A mixed bed type condensate demineralization tower provided in a condensate treatment system of a power plant, and a regeneration equipment for regenerating the ion exchange resin taken out from the condensate demineralization tower, The ion-exchange resin taken out from the condensate demineralization tower and transferred to the regeneration equipment is taken out of the resin transfer pipe, and the ion-exchange resin mixed in the regeneration equipment is received in the demineralization tower. In the condensate desalination apparatus, which is provided with a return pipe for recycled resin that is piped for the purpose of returning the regenerated resin to the condensate demineralization tower by entraining water through this return pipe, connected to the condensate demineralization tower. A condensate demineralizer, characterized in that an entrained water amount adjusting means for reducing the amount of resin-entrained water in the return pipe is provided near the connection portion of the returned return pipe to the condensate demineralization tower. 2. The condensate desalination apparatus according to claim 1, wherein the entrained water amount adjusting means has a screen and a means for flowing a slurry containing the regenerated resin and entrained water onto the screen. 3. The screen according to claim 2, wherein the screen is formed by arranging a large number of metal plates side by side with a minute gap therebetween in the thickness direction, and is erected obliquely. Condensate demineralizer. 4. The screen opening size according to claim 2 or 3, wherein the opening size of the screen is set as large as possible within a range in which the ion exchange resin used has a lower limit particle size when it is new. A characteristic condensate demineralizer. 5. The condensate demineralizer according to claim 4, wherein the screen has an opening size of 0.25 to 0.30 mm. 6. The method according to any one of claims 1 to 5,
The entrained water amount adjusting means is for adjusting the entrained water of the regenerated resin that is received in the condensate demineralization tower so that the amount of water is 0.6 to 0.7 times that of the resin. Condensate demineralizer.