JP5526892B2 - Operation method of ion exchanger - Google Patents

Description

  The present invention relates to an operation method of an ion exchange apparatus having a plurality of ion exchangers such as an ion exchange tower, and in particular, after the water is passed through each ion exchanger in series, the topmost ion exchanger is subjected to maintenance. In particular, the present invention relates to a method of operating an ion exchange apparatus in which the water flow is resumed with the water flow rank at the end.

  Conventionally, ultrapure water has been used in cleaning processes in the field of semiconductor manufacturing and the like. This ultrapure water is required to be free of fine particles, organic matter, and inorganic matter that cause cleaning problems. For example, resistivity: 18.2 MΩ · cm or more, φ0.05 μm fine particles: 1 piece / mL or less, Bacteria: 1 piece / L or less, TOC (Total Organic Carbon): 1 μg / L or less, metal: 1 ng / L or less, ions: 1 ng / L or less are required water quality.

  A non-regenerative ion exchange apparatus is installed in the sub-system of the ultrapure water production apparatus and immediately before the sub-system in order to prevent contamination with regenerative chemicals. Since this non-regenerative ion exchange apparatus does not perform regeneration, maintenance (exchange of ion exchange resin) is required.

  In the case of an ion exchange device that allows water to flow in series to a plurality of ion exchange towers, maintenance can be performed on the ion exchange tower on the topmost side (the most upstream side), then it can be placed at the end and water flow can be resumed. (For example, Patent Document 1).

  In Patent Document 1, for example, when water is passed through three ion exchange modules A, B, and C in the order of A → B → C, and the ion exchange module of A breaks (breaks), the module A is a new one. It replaces with a module and water is passed in the order of B → C → (new module) to resume water flow (FIG. 7 of Patent Document 1).

JP-A-6-206069

  When the new module is arranged at the end as in Patent Document 1 and water flow is resumed, organic substances and the like are eluted from the ion exchange resin in the new module at the initial stage of water flow, and the quality of ultrapure water is improved. May be lower.

  An object of the present invention is to provide an operation method of an ion exchange apparatus in which deterioration of water quality due to elution of organic substances and the like from such a novel ion exchange resin is prevented.

The operation method of the ion exchange apparatus according to the present invention (Claim 1 ) is an operation method of the ion exchange apparatus having the first to nth (n is an integer of 4 or more) ion exchangers, the first to nth. In the operation method of the ion exchange apparatus in which the first ion exchanger is subjected to maintenance of ion exchange resin replacement , and then the water supply order is changed and the water supply is resumed. water passing sequentially after water resumed, the ion exchanger (n-1) and trailing the first ion exchanger from the end subjected to the maintenance water flow ranking until it was the second from the end It is the second, and the flow order of the other ion exchangers is the order in which the previous ranks are small.

In the ion exchange apparatus of the present invention, the ion exchanger that has undergone maintenance is placed second from the end, the second ion exchanger from the end is placed at the end, and the other ion exchangers are the water passing order of ascending order of up to it. Therefore, even if organic substances and the like are eluted from the new ion exchange resin, the organic substances and the like are captured by the last ion exchanger and do not flow out of the ion exchange device. The ion exchanger that was placed at the end was the one that was placed second from the end so far. Because there is, organic matter does not flow out. Therefore, the water quality rises well when the water flow is resumed.

In the present invention, the ion exchangers other than the two ion exchangers on the end side are arranged in ascending order of the water flow order until then, and the ion exchange capacity is larger in the downstream side. Therefore, ultrapure water or the like can be efficiently produced using the remaining ion exchange capacity without waste.

It is explanatory drawing of the operating method of the ion exchange apparatus which concerns on a reference example . It is explanatory drawing of the operating method of the ion exchange apparatus which concerns on embodiment of this invention. It is a graph which shows an experimental result.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a water flow diagram of an ion exchange device for passing water in series to three ion exchange towers A, B, and C.

  In FIG. 1 (a), the water to be treated from the pipe 1 is passed through the pipe 1, the ion exchange tower A, the pipe 2, the ion exchange tower B, the pipe 3, the ion exchange tower C, and the pipe 4 in this order. . When the ion exchange tower A breaks or is approaching a break by continuing this water flow, the ion exchange tower A is maintained and water is passed as shown in (b).

  In (b), the water to be treated is passed through pipes 1, 10, 12, ion exchange tower C, pipe 20, ion exchange tower A, pipe 2, ion exchange tower B, and pipe 22 in this order. When the ion exchange column C breaks or is about to break by continuing this water flow, the ion exchange column C is maintained and water is passed as shown in (c).

  In (c), treated water is passed through pipes 1, 10, 11, ion exchange tower B, pipe 3, ion exchange tower C, pipe 20, ion exchange tower A, and pipe 21 in this order. When the ion exchange tower B breaks or is approaching a break by continuing this water flow, the ion exchange tower B is maintained and water is passed as shown in (d). This (d) is the same as (a).

Thus, in the case of FIG. 1, the water flow order to the ion exchange towers A, B, C is
(A) A → B → C
(B) C → A ^* → B
(C) B → C ^* → A
It will be going around the three ways. Note that * indicates an ion exchange column immediately after maintenance.

  That is, in FIG. 1, when water flow is resumed after maintenance, the ion exchange tower that has been placed at the end until then (that is, in the previous water flow process) is the top, and the ion exchange tower that has been maintained is the second. And the ion exchange tower arranged second from the end is the end. For this reason, the effluent water from the ion exchange tower equipped with the new ion exchange resin can be passed through the last ion exchange tower, and even if organic substances are eluted from the new ion exchange resin, the last ion exchange is performed. Captured by the tower. Moreover, the ion exchange etc. which are newly arranged at the end have already passed water, and organic substances do not flow out. Therefore, the water quality rise is good when water flow is resumed.

  Each of the pipes 1 to 3, 10 to 12, and 20 to 22 is provided with a valve (not shown) for switching the flow path.

  FIG. 2 is a water flow diagram of an ion exchange device for passing water in series to four ion exchange towers A, B, C, and D.

  In FIG. 2 (a), the water to be treated from the pipe 1 is the pipe 1, the ion exchange tower A, the pipe 2, the ion exchange tower B, the pipe 3, the ion exchange tower C, the pipe 4, the ion exchange tower D, Water is passed in the order of the pipe 5. When the ion exchange tower A breaks or is approaching a break by continuing this water flow, the ion exchange tower A is maintained and water is passed as shown in (b).

  In (b), the water to be treated is pipes 1, 10, 11, ion exchange tower B, pipes 70, 71, ion exchange tower D, pipes 50, 53, ion exchange tower A, pipes 60, 61, ion exchange tower. Water is passed in the order of C and pipes 40 and 41. When the ion exchange tower B breaks or is approaching a break by continuing this water flow, the ion exchange tower B is maintained and water is passed as shown in (c).

  In (c), the water to be treated is pipes 1, 10, 13, ion exchange tower D, pipes 50, 51, ion exchange tower C, pipes 40, 42, ion exchange tower B, pipes 70, 73, ion exchange tower. Water is passed in the order of A and pipes 60 and 63. When the ion exchange tower D breaks or is approaching a break by continuing this water flow, the ion exchange tower D is maintained and water is passed as shown in (d).

  In (d), the water to be treated is pipes 1, 10, 12, ion exchange tower C, pipes 40, 43, ion exchange tower A, pipes 60, 62, ion exchange tower D, pipes 50, 52, ion exchange tower. Water is passed through B and piping 70 and 72 in this order. When the ion exchange column C breaks or is approaching a break by continuing this water flow, the ion exchange column C is maintained and water is passed as shown in (e). This (e) is the same as (a).

Thus, in the case of FIG. 2, the order of water flow to the ion exchange towers A, B, C, D is
(A) A → B → C → D
(B) B → D → A ^* → C
(C) D → C → B ^* → A
(D) C → A → D ^* → B
There are four ways to go around.

  That is, in FIG. 2, when water flow is resumed after maintenance, the ion exchange tower that has been maintained is the second ion from the end, and the ion that has been placed second from the end until then (that is, in the previous water flow step). The exchange tower ends. The other two orders shall be the order of the previous water flow order. For this reason, the effluent water from the ion exchange tower equipped with the new ion exchange resin can be passed through the last ion exchange tower, and even if organic substances are eluted from the new ion exchange resin, the last ion exchange is performed. Captured by the tower. Moreover, the ion exchange etc. which are newly arranged at the end have already passed water, and organic substances do not flow out. Therefore, the water quality rise is good when water flow is resumed. Also, since the water flow order on the upstream side of the maintained ion exchange tower is the order in which the water flow order is younger, the higher the remaining amount of ion exchange capacity is on the downstream side, the remaining ion exchange Ultrapure water and the like can be efficiently produced using the capacity without waste.

  Each of the pipes 1 to 3, 10 to 13, 40 to 43, 50 to 53, 60 to 63, and 70 to 73 is provided with a valve (not shown) for switching the flow path. Yes.

In FIG. 2, water is passed in series to 4 ion exchange towers, but the flow order is changed when water is passed in series to 5 or more (usually 3 or less) ion exchange towers. In the same manner, that is, the ion exchange tower that is the second from the end is the end, the ion exchange tower that has been maintained is the second from the end, and the others are arranged in ascending order of the water flow order of the previous water flow process. Done. For example, the change of the water flow order of five ion exchange towers A to E is as follows.
(A) A → B → C → D → E
(B) B → C → E → A ^* → D
(C) C → E → D → B ^* → A
(D) E → D → A → C ^* → B
(E) D → A → B → E ^* → C
(A) A → B → C → D ^* → E (as in (a) above)
As described above, * indicates that the ion exchange tower is immediately after maintenance.

  In this way, after the maintenance (resin exchange) of the top ion exchange tower that is most loaded, this ion exchange tower was placed one position from the end, and water was passed from the end one position before maintenance. Water is passed through the ion exchange apparatus as the end, and other ion exchange towers are sequentially shifted forward. Thereby, the initial elution from the ion exchange resin immediately after the maintenance can be removed by the ion exchange device at the end. In addition, since the ion exchange apparatus at the end is sufficiently passed before maintenance, the initial elution is sufficiently reduced. Therefore, initial elution from the ion exchange resin can also be removed, and high-purity water quality can be provided from the beginning.

  In order to verify the effect of the present invention, the following experiment was conducted.

[Experiment 1]
An ion exchange resin (Cation: EX-CG, anion: EX-AG, manufactured by Dow Chemical, Volume ratio of anion exchange resin and cation exchange resin is 1: 1) is packed in a column of φ40 mm × H500 mm, and the two columns are connected in series. The first water flow was performed for one week or longer (SV = 30 for each column).

  Then, after exchanging the resin for the former column, it was returned to the former column and water flow was resumed. And the TOC of the column outlet of the back | latter stage after water flow restarting was measured with the TOC meter (ANATEL A-1000). The results are shown in FIG.

  As shown in FIG. 3, the column effluent at the latter stage had a low TOC of about 0.5 μg / L even immediately after resuming water flow. This indicates that the organic matter flowing out from the maintained front column is sufficiently captured by the rear column.

[Experiment 2]
Two columns similar to those in Experiment 1 were prepared, connected in series, and the first water flow was performed in the same manner as in Experiment 1. Next, after the resin was exchanged for the latter column, it was returned to the latter column and water flow was resumed. The start-up data after restarting water flow (TOC concentration at the downstream column outlet) was collected and shown in FIG.

  As shown in FIG. 3, in Experiment 2, the TOC concentration after resuming water flow is high due to the elution of organic substances from the maintained subsequent column. It took about 4 hours for the TOC concentration to drop to the 0.5 μg / L level.

  From Experiments 1 and 2, it is fully recognized that according to the present invention, the water quality immediately after the resumption of water flow is good.

A, B, C, D Ion exchange tower 1-5, 10-13, 20-22, 40-43, 50-53, 60-63, 70-73 Piping

Claims (1)

An operation method of an ion exchange apparatus having first to nth (n is an integer of 4 or more) ion exchangers,
After passing water through the first to nth ion exchangers in this order, the ion exchange resin is maintained in the first ion exchanger, and then the water exchange order is changed to resume the water flow. In the method
Water passing sequentially after the passing water resumed, it until the end of the ion exchanger of the water passage ranking was the second from the end (n-1), the first ion exchanger which has been subjected to the maintenance A method for operating an ion exchange apparatus, characterized in that the second order from the end is used, and the water flow order of other ion exchangers is the order from the lowest order.

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