JP2950664B2 - Condensate desalination equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A thermal power plant will be described as an example. In a power plant, a turbine is driven by steam generated by a boiler, the turbine is cooled by heat exchange, condensed, and supplied to the boiler again. A condensate circulation system is provided. In order to remove impurities contained in this condensate, a filter and a desalination tower for removing ions are provided in the condensate circulation system. Here, the desalination tower provided in the condensate circulation system for treating the condensate constitutes a condensate desalination device 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 desalination towers and a series of regeneration facilities connected in parallel to these.

[0003] An example of such a condensate treatment and an outline of its operation will be further described. Usually, in a condensate circulation system, condensate is treated by a plurality of desalination towers. When the pressure loss increases or when the yield reaches a certain level, the ion exchange resin (that is, used resin) in the desalting tower is transferred to the regeneration facility, and at the same time, is regenerated and stored in the regeneration facility. The desalination tower is charged with the regenerated resin and the operation is resumed. The resin transferred to the recycling facility is subjected to a regeneration process according to a predetermined procedure, and is prepared for replacement with the next used resin. The regeneration equipment used in the condensate desalination equipment and its operation include cation exchange resin (CER) and anion exchange resin (AE).
There are various methods such as a method in which R) is regenerated in a separate tower and a method in which R) is regenerated in a single tower.

[0004] In a 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, a cation exchange resin and a cation exchange resin are used in a regeneration tower. There are known a method in which a resin is mixed and then charged (returned) into a desalination tower, and a method in which both ion exchange resins are mixed in a desalination 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 an operation of mixing air (for several minutes) with water being spread to a certain height above the resin layer. In this case, the mixed state of the two resins can be favorably obtained during the air mixing, but there is a problem that it is difficult to avoid a phenomenon of specific gravity separation when the resin is settled after the mixing. In order to reduce the influence, the blow valve is opened immediately after mixing the air, 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 mixing ratio of the anion exchange resin is insufficient at the lower part of the mixed resin layer. As a result, for example, after periodic inspection of the power plant facilities, auxiliary materials such as rust preventives and anti-seizure agents are removed. When brought into the salt column, contamination of the anion exchange resin occurs, which may reduce the capacity of the anion exchange resin. When a resin is used, trapping by a small amount of an anion exchange resin such as Cl ⁻ (or SO ₄ ⁻ ) leaking from the cation exchange resin below the mixed resin layer deteriorates, and the quality of treated water deteriorates.

[0006] Further, after the resin in the mixed state is returned to the desalting tower in the regenerating facility, the mixing operation is performed again, so that there are many losses in terms of time and equipment.

On the other hand, the above-mentioned method of returning the mixed resin in the regenerating facility to the desalting tower in a mixed state is very advantageous because the resin mixed in advance can be transferred to the desalting tower, but it is accompanied by water. Resin entrained water is excessive because it passes through the return pipe at a large linear flow velocity, and the resin around the outlet is disturbed by a large amount of water when guided into the desalination tower, and the resin is separated as it goes away from the outlet. Come up. For this reason, even in this method, there is a disadvantage that the mixing ratio of the anion exchange resin is insufficient at the lower portion of the mixed resin layer.

[0008]

SUMMARY OF THE INVENTION The inventor of the present invention has made intensive studies to solve the problems of the prior art in the above-described condensate desalination apparatus, and has proposed the present invention.

That is, an object of the present invention is to utilize the advantage of a system in which mixed resin is returned from a regenerating facility to a desalination tower by using excess entrained water (remixing operation in the desalination tower is not required). Ideally, it adopts a mixed resin return method that has no operational time loss and no equipment loss, and does not exhibit the mixing unevenness due to the specific gravity separation of both resins, which is a drawback of the conventional method. It is an object of the present invention to provide a condensate desalination apparatus which can secure a state similar to a typical uniform mixing state.

Another object of the present invention is to ensure uniform mixing of the cation exchange resin and the anion exchange resin in the condensate desalination tower, thereby obtaining a condensate with excellent treated water quality. To provide equipment that can maintain the water desalination tower.

Still another object of the present invention is to provide a condensate desalination apparatus which does not require remixing in a desalination tower, requires no additional equipment, and has a short regeneration time. .

Another object of the present invention is to provide an apparatus capable of achieving the above object and simultaneously removing the ion-exchange resin, which has been abraded or crushed with the lapse of time and atomized, out of the system. It is in.

[0013]

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

The condensate desalination apparatus of the present invention typically includes a mixed-bed condensate desalination tower provided in a condensate treatment system of a power plant, and a condensate desalination tower. A regeneration facility for regenerating the ion-exchange resin, a resin take-out transfer pipe that is installed to take out the ion-exchange resin from the condensate demineralization tower and transfer it to the regeneration facility, and a mixing state in the regeneration facility. A return pipe for regenerated resin piped to receive the ion-exchanged resin into the desalination tower, and return the regenerated resin to the condensate desalination tower with water through the 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 a connection portion of the return pipe connected to the condensate demineralization tower to the condensate demineralization tower. It is characterized by having.

The above-mentioned entrained water amount adjusting means is constituted by, for example, a screen and a means for flowing a slurry containing regenerated resin and entrained water on the screen. A plate formed by arranging the plates side by side with a small gap in the thickness direction can be preferably used. As this screen, for example, a plate provided with a large number of small projections is inserted and hung on a common hanging rod, and a large number of such plates are stacked so that the small projections serve as spacers. By adopting a material sandwiched from both ends, a screen having an accurately set aperture size can be formed. In addition, by setting the size of the opening as large as possible (for example, 0.25 to 0.30 mm) as long as the ion exchange resin to be used does not pass the new particle having the lower limit particle size at the time of brand-new, the crushing is performed. There is an advantage that the ion-exchange resin, which has been atomized by the method described above, can be dropped under the screen and removed from the system.

By using the entrained water amount adjusting means as described above, the mixed resin can be smoothly transferred with excess entrained water in the return pipe on the upstream side (regeneration facility side). Downstream side of means (desalination tower side)
Thus, the amount of the accompanying 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]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to 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 FIG. 3, only one desalination tower 40 is shown for the sake of convenience with respect to the regeneration equipment 30. . The illustration of the condensate circulation system provided with the desalination 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
Spent mixed resin 2 transferred from inside via transfer pipe 21
And 0 into the separation and cation exchange resin regeneration tower 1,
After sufficient scrubbing with air or the like to discharge the clad of iron oxide or the like to the outside by a water flow, backwash water in an upward flow is flowed from the lower portion of the regeneration tower 1 to sufficiently expand both ion exchange resins, and By utilizing the difference in the sedimentation speed of the exchange resin, the cation exchange resin is gathered in the lower layer and the anion exchange resin is gathered in the upper layer, and then the inflow of the backwash water is stopped and settled. An anion exchange resin layer 7 is formed on the upper layer.

Next, a small amount of the anion exchange resin 7a (shown by oblique lines in the figure) remains above the separation interface 8 between the two ion exchange resins, and most of the other anion exchange resins 7 are transferred through the resin transfer tube 9. Transferred to the anion exchange resin regeneration tower 3 and then the remaining small amount of the anion exchange resin 7a;
A small amount of cation exchange resin 6a below the separation interface 8
(Shown by oblique lines) is transferred to the mixed resin receiving tank 2 using the resin transfer pipe 10. After such a transfer is completed,
In the separation and cation exchange resin regeneration tower 1, an acid regenerant is passed from the outside via an acid regenerant drug delivery tube 11 and a distributor 12, then extruded and washed, and the cation exchange resin 6 is regenerated by a conventional method. .

On the other hand, also in the anion exchange resin regeneration tower 3, the alkali regeneration agent passage tube 13 and the distributor 14
The alkali regenerant is passed from the outside through the above, then extruded and washed, and the anion exchange resin 7 is regenerated by an ordinary method.

After the above regeneration is completed, the regenerated cation exchange resin 6 in the separation and 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 is transferred to the resin storage tank 4 via the resin transfer pipe 16, and after the transfer, both ion exchange resins are sufficiently mixed and stored as a regenerated mixed resin. Then, the mixed resin stored in the resin storage tank 4 is transferred (returned) to the desalination tower 40 (actually, a different desalination tower than the illustrated one 40) via the resin return pipe 17 when required.

Next, a detailed configuration for receiving the returned mixed resin into the desalination tower 40, which is a characteristic part of the present embodiment of the condensate desalination apparatus having the configuration described above with reference to FIG. 3, will be described. .

FIG. 1 shows an outline of the structure of the desalination tower 40. The desalination tower 40 is provided, for example, in a condensate circulation system of a thermal power plant (not shown). The condensed water passes through the condensate inlet pipe 43 from the upper distributor 44 into the tower, and passes through the mixed resin layer filled therein, thereby collecting the lower water collector 4
., Through the outlet pipe 46, and sent to the boiler again.

After the mixed resin in the desalting tower 40 has been used for a predetermined period of time, it is transferred to the regenerating facility for regenerating treatment, as described above. From the resin storage tank 4 of the regeneration facility 30, the tower 47 is supplied with a slurry 47 of the regenerated mixed resin together with the accompanying water (second slurry).
(See the figure) is returned through the return pipe 17.

A feature of this embodiment is that an entrained water amount adjusting device 41 is provided near the connection of the return pipe 17 to the desalination tower 40, and the amount of entrained water is reduced through the entrained water amount adjusting device 41. Resin slurry 48 (for example, 0.6 to resin)
０．７0.7 times the amount of entrained water) is charged from the resin filling nozzle 42 into the desalination tower 40.

The entrained water amount adjusting device 41 of this embodiment is
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 (an extended part of the return pipe 17) is provided. The opening 412 is provided so as to be substantially horizontally opposed to the screen 413. This is because better drainage can be obtained compared to a method in which the slurry 47 simply flows down the screen. The water that has passed through the screen 413 is sent to an appropriate drainage device through a drainage pipe 414, but may be reused after passing through a filter or the like. The slurry 48 having a reduced amount of entrained water flowing on the screen 413 is filled into the desalination tower 40 from the resin filling nozzle 42 through the resin supply chute 415.

The present invention is, of course, not limited to the above-described embodiments. For example, the present invention is not limited to the method of regenerating used resin, and the resin regenerated by any known regenerating method can be removed. The present invention can be applied to the case of returning to the salt tower. Further, the accompanying water amount adjusting device is not limited to the above configuration. For example, it is particularly preferable that a screen is formed by forming a large number of small projections of about 0.3 mm on a stainless steel plate made of a corrosion-resistant material by pressing or the like and laminating a large number of these in the thickness direction. According to such a configuration, for example, these many stainless steel plates are inserted and hung on a common hanging bar (for example, two parallel bars), and the laminated body is loosened and pressure is applied from both sides. By being provided so as to be able to switch between these states, it is possible to use the screen as a pressed state when in use, and release the pressed state during clogging cleaning so that cleaning can be performed easily. In addition, this method not only facilitates the cleaning operation for eliminating clogging, but also strictly determines the size of the openings of the screen by accurately setting the dimensions of the small projections. The ion-exchange resin, which has the same particle size as above, does not pass through, but the resin that has become smaller over time due to its use should be allowed to pass, and the worn or crushed resin should be removed and discharged through this screen. There is an advantage that becomes possible. The resin having such a small particle diameter causes an increase in the pressure loss of the desalting tower or a problem that the ion exchange performance is not properly exhibited, and is unevenly distributed during settling in the desalting tower or the regeneration storage tank. Because of the problem of tendency, the effect of the removal is extremely large.

Test Example 1 Using the apparatus shown in FIGS. 1 and 2, a mixed resin was charged into a desalination tower. 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 mixing ratio of the anion exchange resin in the mixed resin layer was measured according to the following method.

First, water is temporarily drained from the resin tower which is in a full state after the resin transfer is completed, and a manhole provided at the upper part of the resin tower is opened. Next, from the lower part of the resin tower, water having a slow flow rate (LV = 1 m / H) that does not separate the mixed resin in the tower flows in an ascending flow, and when the water reaches the upper part of the resin layer, 400m from the center and the center of the resin tower from the manhole
Sampling pipes made of hard PVC with a diameter of 1 inch and a length of 1.5 m are vertically inserted into the resin layers at positions m and 800 mm apart, respectively. By inserting each sampling pipe to the lower part of the resin layer, the ion exchange resin is introduced into each sampling pipe while maintaining the initial filling state.

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

When drainage is completed, the sampling pipe is carefully extracted from the resin layer, and then each sampling pipe is cut from the lower end at equal intervals of 200 mm.

The ion exchange resin in each pipe cut to 200 mm is taken out, put into a measuring cylinder, saturated saline is added thereto, and the mixture is stirred to separate the cation exchange resin and the anion exchange resin by a difference in specific gravity. Thereafter, the amount of each resin was measured to determine the mixing ratio.

[0033]

[Table 1]

[0034]

[Table 2]

As can be seen from the results, the mixed resin layer in the desalting tower is filled at a height of every 200 mm from the lower part of the resin layer, and from the center to the peripheral part in a state approximate to the ideal value. This confirms that the quality of the treated water is greatly improved as compared with the case of the conventional method.

Comparative Test Example 1 For comparison, a mixing operation in which a mixed resin was charged into a desalting tower 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 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 a system for returning the mixed resin regeneration equipment to the desalination tower by using excess entrained water is employed, the operation of remixing in the desalination tower is unnecessary. There is an advantage that there is no time loss and no equipment loss,
Also, since the amount of water entrained in the mixed resin that is accepted in the desalting tower is adjusted very quickly, the ideal uniform mixing state without the mixing inconsistency due to the specific gravity separation of both resins, which was a drawback of the conventional method There is an effect that a state similar to the above can be secured.

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

Still further, since remixing in the desalting tower is unnecessary, an additional facility is not required, and a condensate desalination apparatus having a short regeneration time can be provided.

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

[Brief description of the drawings]

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

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

FIG. 3 is a diagram showing an example of a configuration outline of a regeneration facility of a condensate desalination apparatus to which the present invention is applied.

[Explanation of symbols]

40 ... desalination tower, 41 ... entrainment water amount adjusting device, 42
... Nozzle for filling mixed resin, 43 ... Condenser inlet pipe, 4
4 ... distributor, 45 ... water collector, 46 ... outlet pipe, 47 ... slurry, 48 ...
・ Resin slurry, 411 ・ ・ ・ Mixed resin slurry introduction tube, 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.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C02F 1/42 B01J 47/04 B01J 49/00 G21F 9/12

Claims (6)

(57) [Claims] 1. A mixed-bed condensate desalination tower provided in a condensate treatment system of a power plant, a regeneration facility for regenerating an ion exchange resin taken out of the condensate desalination tower, and The resin is taken out of the condensate desalination tower and taken out of the condensate desalination tower and transferred to the regeneration equipment. The resin transfer pipe and the ion exchange resin mixed in the regeneration equipment are received in the desalination tower. And a return pipe for the regenerated resin piped in order to return the regenerated resin to the condensate desalination tower with water through the return pipe. A condensate desalination apparatus, characterized in that an entrained water amount adjusting means for reducing the amount of resin entrained water in the return pipe is provided in the vicinity of a connection portion of the returned return pipe to the condensate desalination tower. 2. The condensate desalination apparatus according to claim 1, wherein the entrained water amount adjusting means has a screen and means for flowing a slurry containing 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 small gap in the thickness direction, and is installed diagonally. Condensate desalination equipment. 4. The method according to claim 2, wherein the size of the opening of the screen is set as large as possible within a range that does not allow the ion-exchange resin to be used to pass the ion-exchange resin having a lower limit particle size when new. Condensate desalination equipment characterized. 5. The condensate desalination apparatus according to claim 4, wherein the screen has a mesh size of 0.25 to 0.30 mm. 6. The method according to claim 1, wherein
The entrained water amount adjusting means adjusts the entrained water of the regenerated resin received in the condensate demineralization tower so that the amount of water is 0.6 to 0.7 times the amount of the resin. Condensate desalination equipment.