JP2020075226A - Regeneration device for ion exchange resin - Google Patents

Abstract

To provide a regeneration device for ion exchange resins capable of reducing the turbulent flow of a back washing water in the vicinity of a resin separation boundary face to improve a resin separation precision.SOLUTION: In an ion exchange resin regeneration device for condensate demineralization, a condensate demineralizing tower 1, cation exchange resin regeneration tower 3, anion exchange resin regeneration tower 5 and resin storage tank 8 are connected by pipe arrangement to enable a resin transfer. In the device, an anion exchange resin outlet 20 is provided on the way in a cation exchange resin regeneration tower 10, and a pipeline 31 is connected to the outlet via the branch pipelines 30. Besides, an anion exchange resin extraction pipeline 35 is branched from the pipeline 31, and a chemical-feeding pipeline 36 is connected to the pipeline 31.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ion exchange resin regenerator for a condensate demineralizer, and more particularly to an ion exchange resin regenerator for a condensate demineralizer in a thermal power plant, a nuclear power plant or the like.

  Usually, in the condensate desalination, 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 chemical liquid regeneration is performed with sulfuric acid and caustic soda (for example, Patent Document 1, 2).

  The ion exchange regeneration device and the regeneration method described in Patent Document 1 will be described with reference to FIGS. 5 and 6A to 6C. This regenerator comprises a condensate demineralizer 1, a cation exchange resin regenerator 3, an anion exchange resin regenerator 5, a resin storage tank 8 and pipes 2, 4, 6, 7, which connect these to enable resin transfer. 9 is an ion exchange resin regenerator in a condensate demineralizer using an out-of-column regeneration system having 9. The condensate demineralization 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 by the valve (not shown) provided in each pipe being closed. Desalination treatment is performed by passing condensate water to the condensate desalination tower 1 only through the pipes 1a and 1b. Regeneration of the ion exchange resin by this regenerator is performed by the following resin removal / separation step, backwash regeneration step and resin mixing / returning step.

<Resin removal / separation process>
(i) Stop the passage of liquid through the pipes 1a and 1b and disconnect the condensate demineralization tower 1 from the main system.
(ii) The ion exchange resin in the condensate demineralization tower 1 is transferred to the cation exchange resin regeneration tower 3 through the pipe 2. (Fig. 6 (a))
(iii) As shown in FIG. 6 (b), by passing backwash water through the cation exchange resin regeneration tower 3 in an upward flow, the ion exchange resin in the mixed state is anion exchange resin and cation exchange resin with a specific gravity difference. Is separated into upper and lower layers.
(iv) As shown in FIG. 6C, the anion exchange resin is selectively drawn out through the pipe 4 and transferred to the anion exchange resin regeneration tower 5.

  In addition, in patent document 2, after that, as shown in FIG.6 (d)-(f), resin separation and transfer are performed again. That is, when the anion exchange resin is discharged / transferred to the level of the anion exchange resin discharge port 4a, as shown in FIG. 6C, anion exchange resin is discharged between the anion exchange resin discharge port 4a and the cation exchange resin layer upper surface. A mixed layer of the resin and the cation exchange resin remains.

  Therefore, the backwash water is backwashed by accelerating the LV and flowing upward to push up the interface between the mixed layer and the cation exchange resin layer and promote further resin separation in the mixed layer (FIG. 6 (d)). The upward flow rate of the backwash water was adjusted so that this interface dropped to the vicinity of the anion exchange resin discharge port 4a (FIG. 6 (e)), and then the mixed resin of the anion exchange resin and the cation exchange resin forming the mixed layer was changed to the anion. The resin is transferred to the resin storage tank 8 through the exchange resin discharge port 4a, the pipe 4 and the pipe 7A (FIG. 6 (f)). Thereby, the residual amount of the anion exchange resin in the cation exchange resin in the cation exchange resin regeneration tower 3 is significantly reduced.

<Backwash regeneration process>
(v) In the cation exchange resin regeneration tower 3, while the ion exchange resin is immersed in water, air is blown from the bottom (air scrubbing) to remove the corrosion products (clad etc.) attached to the resin.
(vi) In the cation exchange resin regeneration tower 3 for the cation exchange resin and in the anion exchange resin regeneration tower 5 for the anion exchange resin, the chemical solution is regenerated by injecting acid and alkali, respectively.

<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 pipe 6 and the pipe 7, respectively.
(viii) The resin storage tank 8 is washed and mixed.
(ix) The ion exchange resin in the resin storage tank 8 is returned to the condensate demineralization tower 1 through the pipe 9 in the mixed state.
(x) The passage of the pipe 9 is stopped, and the condensate demineralization tower 1 is used as a standby tower and put in a standby state.

  As a result, since the regeneration is completed, the condensate water flow is restarted through the pipes 1a and 1b, and the desalination process operation is returned to.

JP-A-55-051445 Japanese Unexamined Patent Application Publication No. 2018-1266887

  In a conventional cation exchange resin regeneration tower, although not shown, a drainage pipe and a chemical injection pipe are arranged below the anion exchange resin discharge port 4a. The drainage pipe is a wedge pipe or the like, which is a straight pipe from which resin does not flow out and only water and fine iron clad are discharged. The chemical injection pipe is a radial pipe provided with a small hole facing downward, and is installed below the resin discharge port 4a.

  However, since the locations where these pipes are installed are near the resin separation boundary surface in the backwash separation of the mixed resin, the backwash flow hits the chemical injection pipe and turbulent flow occurs, which disturbs the resin separation boundary surface and causes anions. This has been a cause of promoting the mixing of the cation exchange resin into the exchange resin layer.

  It is an object of the present invention to provide an ion exchange resin regenerator that can reduce the turbulence of the flow of backwash water near the resin separation boundary surface and improve the resin separation accuracy.

  The ion exchange resin regenerator of the present invention comprises a condensate demineralization tower, a cation exchange resin regenerator tower, an anion exchange resin regenerator tower, and a resin storage tank, which are connected by a pipe in a resin transferable manner for condensate demineralization ions. In the exchange resin regeneration device, a resin injection pipe for connecting the anion exchange resin discharge port and the anion exchange resin regeneration tower, which is provided in the vertical direction of the cation exchange resin regeneration tower, and a chemical injection section for supplying a regenerant, are provided. It is connected.

  In one aspect of the present invention, the chemical injection unit includes a chemical injection pipe provided in a vertical direction and in which the regenerant flows downward, and a chemical injection valve provided in the chemical injection pipe.

  In one aspect of the present invention, a tubular drainage port is provided above the anion exchange resin discharge port.

  In the present invention, the anion exchange resin drawing pipe and the chemical injection pipe are shared. That is, the chemical liquid is injected from the anion exchange resin drawing pipe, and the chemical injection pipe in the cation exchange resin regeneration tower is omitted. Also, preferably, the tubular drainage port is arranged above the anion exchange resin discharge port. As a result, the structure below the resin discharge port is eliminated, and the backwash water for separating the mixed resin is rectified.

  Further, the structure inside the cation exchange resin regeneration tower is simplified, and the cation exchange resin regeneration tower is easily manufactured.

It is a systematic diagram of the ion exchange resin regeneration device which concerns on embodiment. It is a sectional view of a part of the cation exchange resin regeneration tower of FIG. It is sectional drawing of the resin discharge port of FIG. (A) is a top view of a radiation piping, (b) is the side view. It is a systematic diagram of the ion exchange resin regeneration device which concerns on a prior art example. It is explanatory drawing of the resin separation process in a cation exchange resin regeneration tower. It is sectional drawing which shows a comparative example.

  Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a system diagram showing an ion exchange resin regeneration device according to an embodiment, and a cation exchange resin regeneration tower is shown as a schematic vertical section.

  A lower water collecting plate 11 is installed in the lower portion of the cation exchange resin regeneration tower 10, and the resin is stored on the upper side of the lower water collecting plate 11. A pipe 12 for discharging resin, which has a valve V8, is connected to the lower water collecting plate 11. To the bottom tube plate of the cation exchange resin regeneration tower 10, a pipe for supplying reclaimed water 37 described later is connected.

  A pipe 13 for introducing resin having a valve V4 is connected to the top of the cation exchange resin regeneration tower 10. A drainage section 14 made of a perforated pipe is installed in the upper part of the cation exchange resin regeneration tower 10, and a pipe 15 having a backwash water discharge valve V6 is connected to the drainage section 14.

  A translucent window portion (reference numeral omitted) is provided on a part of the side surface of the cation exchange resin regeneration tower 10 in the vertical direction, and the cation exchange resin and anion in the cation exchange resin regeneration tower 10 are opposed to the window portion. A sensor 17 for detecting a boundary surface with the exchange resin is installed. As the sensor 17, an optical sensor or the like that detects the boundary surface based on the color difference between the cation exchange resin and the anion exchange resin can be used, but is not limited thereto. As will be described later, the valve V3 for supplying reclaimed water is controlled based on the detection signal of the sensor 17.

  An anion exchange resin discharge port 20 and a tubular drain port 18 (FIG. 2) are installed in the cation exchange resin regeneration tower 10 along the vertical direction. The anion exchange resin discharge port 20 is connected to one end side of a pipe 31 for discharging anion exchange resin and for chemical injection via a branch pipe 30.

  The other end of the pipe 31 is connected to the regeneration water supply unit via the regeneration water valve V2 and the pipes 32 and 33. Examples of the reclaimed water include pure water having an electric conductivity of 1 mS / m or less.

  An anion exchange resin extraction pipe 35 is branched from the middle of the pipe 31, and a resin transfer valve V7 is provided in the pipe 35.

Further, a chemical injection pipe 36 is connected in the middle of the pipe 31, and a chemical injection valve V1 is provided in the pipe 36. The pipe 36 stands up from the pipe 31. The chemical injection valve V1 is provided in the lower portion of the pipe 36, thereby reducing the amount of the chemical liquid (sulfuric acid aqueous solution) remaining in the pipe 36 on the lower side of the valve V1.
The branching position of the anion exchange resin extraction pipe 35 and the branching position of the chemical injection pipe 36 can be either order. However, if the anion exchange resin extraction pipe 35 is closer to the tower 10, the chemical injection pipe 36 Since there is a risk that the chemical liquid diffuses into the anion exchange resin extraction pipe 35 during the flushing after the injection, it is preferable to use the chemical injection pipe 36 closer to the column 10 as shown in FIG. 1 to reduce the risk.

  Pipes 34 and 39 are branched from the recycled water supply pipe 33. The pipe 34 is connected to the pipe 37 via a valve V3. A pipe 38 is branched from the middle of the pipe 37, and a drain valve V9 is provided in the pipe 38. The pipe 39 is connected to the pipe 15 via a valve V5.

  The configuration of the anion exchange resin discharge port 20 will be described with reference to FIGS.

  The one end of the pipe 31 is branched into a plurality of (preferably 3 to 6) radial branch pipes 30. The tip end side of each branch pipe 30 is bent downward. An anion exchange resin discharge port 20 is provided at the lower end on the tip side of each branch pipe 30. The discharge port 20 is open downward as shown in FIG. The discharge port 20 has a taper-shaped cover 24 whose diameter increases toward the bottom.

  The installation level of each outlet 20 is the same. That is, the lower end (opening surface) of each outlet 20 is located on the same horizontal plane.

  An outward flange-like flange 21 is provided at the lower end of the branch pipe 30. Horizontal baffles 22 are arranged at predetermined intervals at the lower end opening of the branch pipe 30 and below the flange 21. The baffle 22 is attached to the flange 21 by bolts 23. A tapered cover 24 is provided so as to surround the lower outer circumference of the branch pipe 30. The cover 24 has a small diameter toward the upper side. The upper end of the cover 24 is connected to the pipe 30. The lower outer peripheral edge of the cover 24 is connected to the outer peripheral edge of the flange 21.

  As shown in FIG. 2, the tubular drainage port 18 is composed of a horizontal perforated pipe. The tubular drainage port 18 is arranged below the horizontal radial portion of the branch pipe 30 and above the opening surface of the anion exchange resin discharge port 20. A drainage pipe 18a is connected to the tubular drainage port 18, and a valve (not shown) is provided in the pipe 18a.

  This ion-exchange resin regeneration device is operated by the following resin removal / separation process, regeneration process, and resin mixing / returning process.

(1) Resin introduction V4 and V6 are opened, and the mixed resin is transferred from the desalting tower to the cation exchange resin regeneration tower 10.

(2) Resin backwash separation V4 is closed, V3 and V6 are opened, and regenerated water is upwardly flowed into the tower 10 at LV8 to 15 m / hr to separate the cation exchange resin and the anion exchange resin into upper and lower two layers. To do.

(3) Height Adjustment of Resin Separation Boundary Surface The opening degree of V3 is adjusted, V6 is opened, and the height of the resin separation boundary surface detected by the sensor 17 is 150 from the lower end of the baffle type resin discharge port 20. The backwash flow rate is adjusted so that the position is below -30 mm.

(4) Anion exchange resin extraction With the opening adjustment of V3 being continued, the resin transfer valve V7 is opened, and then the backwash water discharge valve V6 at the top of the tower is closed. With the backwash water flowing out from the anion exchange resin extraction pipe 35, the anion exchange resin is extracted and transferred to the anion exchange resin regeneration tower. During this time, V3 is adjusted so that the resin separation boundary surfaces have the same height.

  After the drawing of the anion exchange resin is completed, the backwash water discharge valve V6 is opened and the resin transfer valve V7 is closed.

(5) Adjusting the height of the resin separation Sakai interface V6 is opened and the opening of V3 is adjusted so that the height of the resin separation boundary surface detected by the sensor 17 is the lower end (opening) of the baffle type resin discharge port 20. The backwash flow rate is adjusted so that the position is 0 to 20 mm below the surface).

(6) Redrawing of the anion exchange resin The resin transfer valve V7 is opened, and then the backwash water discharge valve V6 at the top of the tower is closed. Anion exchange resin (and mixed cation exchange resin) near the separation boundary surface is transferred to the anion exchange resin regeneration tower along with the backwash water flowing out from the anion exchange resin extraction pipe 35 (anion exchange resin regeneration tower). Open the resin receiving valve on the side). During this time, V3 is adjusted so that the resin separation boundary surfaces have the same height.

  After the extraction of the anion exchange resin is completed, the backwash water discharge valve V6 is opened and the resin transfer valve V7 is closed. Close V3 and stop backwashing.

(7) Regeneration of Cation Exchange Resin After the cation exchange resin has settled, V6 is closed, V1 and V9 are opened, and sulfuric acid for regeneration is supplied at a predetermined SV for a predetermined time.

(8) Extrusion Regeneration After that, V1 is closed, V2 and V9 are opened, and extrusion regeneration is performed with regenerated water.

(9) Washing with water After that, V2 is closed and V5 and V9 are opened to wash with water.

  In the present invention, the anion exchange resin discharge port 40 shown in FIG. 4 may be installed instead of the anion exchange resin discharge port 20.

  The anion exchange resin discharge port 40 has a hollow boss portion 41 and a horizontal tubular body 42 extending from the boss portion 41 in the radial direction (radial direction 8 in this embodiment). The tubular body 42 is provided with a resin inlet 43. 4A is a plan view of the anion exchange resin discharge port, and FIG. 4B is a view taken along the line BB of FIG. 4A. The tubular drain port 18 is installed substantially horizontally below the tubular body 42 and below the pipe 31.

[Example 1]
In the ion exchange resin regeneration device having the configuration of FIGS. 1 to 3, the anion exchange resin discharge port 20 is provided at a position 1600 mm in height from the lower water collecting plate 11 in the cation exchange resin regeneration tower (inner diameter 1900 mm, tower height 5000 mm). I placed it. The following were used as the ion exchange resin.

Cation exchange resin: Diaion UBk14HK (layer height about 1300 mm)
Anion exchange resin: Diaion PA312LOH (layer height about 500 mm)

  The cation exchange resin 3900L and the anion exchange resin 1500L were accommodated in the cation exchange resin regeneration tower 10 in a mixed state. Then, the above steps (1) to (9) were performed as follows. Then, the amount of the cation exchange resin mixed in the anion exchange resin separated and extracted from the cation exchange resin regeneration tower 10 was calculated as the cation exchange resin mixing ratio (volume%) to verify the effect. The results are shown in Table 1 together with the regeneration rate.

  After the backwash water discharge valve V6 is opened and backwash separation is performed to separate the cation exchange resin and the anion exchange resin, the resin separation boundary surface at the sensor 17 is located 110 mm downward from the lower end of the anion exchange resin discharge port 20. Thus, the backwash flow rate was adjusted with V3. The backwashing was continued, the resin transfer valve V7 was opened, and the backwash water discharge valve V6 was closed to transfer the anion exchange resin. The resin being transferred was collected and the mixing ratio of the cation exchange resin contained in the anion exchange resin was measured.

  Next, the backwash LV was adjusted so that the position of the resin separation boundary surface was 20 mm downward from the lower end of the resin discharge port 20, and the resin was transferred near the resin separation boundary surface. After transfer for 20 minutes, backwash was stopped and the cation exchange resin was allowed to settle.

  Next, the chemical injection valve V1 and the drain valve V9 were opened, and 6% sulfuric acid was passed through SV3 (1 / Hr) for 45 minutes. Then, V1 was closed, the reclaimed water valve V2 was opened, and reclaimed water was passed through SV3 (1 / Hr) for 60 minutes. The SV of the regenerated water was raised to 30 (1 / Hr) for washing. Then, air was supplied into the tower to mix the resin, a uniform resin was sampled, and the regeneration rate was calculated from the RH ratio.

[Example 2]
The same operation as in Example 1 was performed except that the configuration near the anion exchange resin outlet was as shown in FIG. Table 1 shows the measurement results of the cation exchange resin mixing ratio and the regeneration ratio.

[Comparative Example 1]
As shown in FIG. 7, in FIG. 2, the tubular outlet 18 is located 200 mm below the anion exchange resin outlet 20. Further, a radial tubular drug injection port (the same shape as in FIG. 4) 50 was arranged 150 mm below the tubular outlet 18. The pipe 36 for chemical injection was connected not to the pipe 31 but to the pipe 51 connected to the tubular chemical injection port 50. Further, the pipe 51 was connected to the pipe 39 via the valve V10 and the pipe 52.

  Similar to the first embodiment, the backwash water discharge valve V6 is opened to perform backwash separation to separate the cation exchange resin and the anion exchange resin, and then the resin separation boundary surface detected by the sensor 17 is the resin discharge port 20. The backwash flow rate was adjusted by V3 so as to be 110 mm below the lower end. The backwashing was continued, the resin transfer valve V7 was opened, and the backwash water discharge valve V6 was closed to transfer the anion exchange resin. The resin being transferred was collected and the mixing ratio of the cation exchange resin contained in the anion exchange resin was measured. Next, the backwash LV was adjusted so that the position of the resin separation interface was 20 mm below the lower end of the resin discharge port 20, and the resin was transferred near the resin separation interface. After transfer for 20 minutes, backwash was stopped and the cation exchange resin was allowed to settle.

  The chemical injection valve V1 and the drain valve V9 are opened, and 6% sulfuric acid is passed through SV3 (1 / Hr) for 45 minutes, V1 is closed and the reclaimed water valve V10 is opened, and reclaimed water is SV3 (1 / Hr) for 60 minutes. I passed water. The SV of the regenerated water was raised to 30 (1 / Hr) for washing. Then, air was supplied into the tower to mix the resin, a uniform resin was sampled, and the regeneration rate was calculated from the RH ratio.

[Comparative example 2]
In Comparative Example 1, the anion exchange resin outlet 20 was the radial anion exchange resin outlet 40 shown in FIG. Otherwise, the same operation as in Comparative Example 1 was performed. Table 1 shows the measurement results of the cation exchange resin mixing ratio and the regeneration ratio.

<Results and discussion>
In Table 1, ◯ is shown when the allowable value of the mixing rate is 0.02 vol% or less, and x is shown when it exceeds the allowable value. Similarly, when the pass rate of the reproduction rate is 80% or more, ◯ is displayed, and when the pass rate is less than 80%, x is displayed.

  In Examples 1 and 2, both the resin mixture rate and the regeneration rate have satisfactory performance. On the other hand, in Comparative Examples 1 and 2, the regeneration rate showed satisfactory performance, but the resin mixing rate exceeded the allowable value. It is considered that this is because the existence of the internal structure below the outlet of the anion resin caused the turbulent flow of the backwash water flow and hindered the resin separation action.

1 Condensate Desalting Tower 3,10 Cation Exchange Resin Regeneration Tower 4 Anion Exchange Resin Transfer Pipe 4a Anion Exchange Resin Discharge Port 5 Anion Exchange Resin Regeneration Tower 8 Resin Storage Tank 17 Resin Interface Detection Sensor 18 Tubular Drain Port 20,40 Anion Exchange Resin Drain port 22 Baffle 50 Chemical injection port

Claims (3)

A condensate demineralization tower, a cation exchange resin regeneration tower, an anion exchange resin regeneration tower, and a resin storage tank in a condensate deionization ion exchange resin regeneration device connected to the resin transferable by piping,
A chemical injection section for supplying a regenerant is connected to a resin transfer pipe that connects the anion exchange resin outlet and the anion exchange resin regeneration tower provided in the up-down direction of the cation exchange resin regeneration tower. Characteristic ion-exchange resin regeneration device.   The said chemical injection part is provided in the up-down direction, and has the chemical injection pipe which the said regenerant flows downward, and the chemical injection valve provided in the said chemical injection pipe. Ion exchange resin regeneration device.   The ion exchange resin regeneration device according to claim 1 or 2, wherein a tubular drainage port is provided above the anion exchange resin discharge port.

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