JPS61153295A - Method for detecting breakage in ion exchange membrane - Google Patents

Abstract

PURPOSE:To detect easily a breakage in an ion exchange membrane fitted to an electrolytic cell without disjointing the cell by measuring the voltage of the unit electrolytic cell while supplying electric current to the electrolytic cell and by judging a breakage to be present in the membrane when the measured voltage is lower than a normal voltage by a specified percentage or more. CONSTITUTION:The electrolytic soln. such as an NaCl or NaOH soln. is filled into an electrolytic cell fitted with an ion exchange membrane, electric current, generally small electric current is supplied to the cell, and a change in the voltage of the unit electrolytic cell is measured. When a breakage such as a pinhole is present in the ion exchange membrane, the measured voltage is lower than a normal voltage by >=10%, so a breakage is judged to be present in the ion exchange membrane when the measured voltage is lower than the normal voltage by >=10%.

Description

【発明の詳細な説明】 ［発明の技術分野］ 本発明は、＊Ｍ槽ｔこ装着されたイオン交換膜の破損な
電解槽友解体することなく容鵬に検知する方法に関し、
特もこアルカリ金属塩化物のイオン交換１［’２電解槽
におりるイオン交換膜のピンホール等の破損による市１
解時の事故を未然に防屯するに適するイオン交換膜の破
損検知方法に関する。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for easily detecting a damaged electrolytic cell of an ion exchange membrane installed in an M tank without dismantling it.
Ion exchange of alkali metal chlorides 1
This invention relates to a method for detecting damage to ion exchange membranes suitable for preventing accidents during disassembly.

［従来技術およびその問題点］ アルカリ金属塩化物を電解して、アルカリ金属水酸化物
および塩素を製造するために、イオン交換膜を隔膜と１
ノで構成した電解槽が用いられる。[Prior art and its problems] In order to electrolyze an alkali metal chloride to produce an alkali metal hydroxide and chlorine, an ion exchange membrane is combined with a diaphragm.
An electrolytic cell constructed of:

Ｉ！１１ち、このような電解槽は、イオン交換膜を介１
１で陽極室と陰極室とにｌメ画された構造で、陽極室に
は食塩水等のアルカリ金属塩化物水溶液が供給され、電
解により濃度の低ドした溶液が戻り塩水として取り出さ
れ、陰極室には純水または希薄な苛性ソーダ等のアルカ
リ金属水酸化物溶液が供給され、電解により所定濃度の
アルカリ金属水酸化物溶液として取り出される。また、
陽極室及び陰極室には電解により発生する塩素ガス及び
水素ガスを抜出すための配管が設けられている。I! 11. In such an electrolytic cell, 1
1 has a structure divided into an anode chamber and a cathode chamber. An alkali metal chloride aqueous solution such as saline is supplied to the anode chamber, and the solution with a low concentration due to electrolysis is returned and taken out as salt water, and the cathode is Pure water or a dilute alkali metal hydroxide solution such as caustic soda is supplied to the chamber, and is taken out as an alkali metal hydroxide solution of a predetermined concentration by electrolysis. Also,
The anode chamber and the cathode chamber are provided with piping for extracting chlorine gas and hydrogen gas generated by electrolysis.

上記した構造の電解槽において、イオン交換膜は電解槽
の組立時における機械的′＠損、あるいは例えば電解槽
の起動や停＋Ｆ、作業中の誤操作あるいは停電などの緊
急時態における後処理などによりピンホールなとの破損
を生じる＋ｑ能性がある。このようなイオン交換膜の破
損に気づかずｖＩｃ解槽０運転なＩＩ＋始、続行するば
あいには、線膜の＠損部溝って陽極室内の塩素ガス中に
陰極室の水素ガスが６−人し、１ｉｌｌらかの着火肺に
より爆発を生じる等の危険な有ｊノたり、陰極室内の苛
性ソーダなど製品の純度が低ドする等の間ｐを招く。【
ノたがって、イオン交換膜の破損な簡便かつ速やかに検
知することが必斐°Ｃある。In the electrolytic cell with the above structure, the ion exchange membrane is damaged due to mechanical damage during assembly of the electrolytic cell, or after-treatment in emergency situations such as starting or stopping the electrolytic cell, incorrect operation during work, or power outage. There is a possibility of damage caused by pinholes. If you do not notice such damage to the ion exchange membrane and continue the vIc decomposition tank 0 operation starting from II+, the hydrogen gas in the cathode chamber will be absorbed into the chlorine gas in the anode chamber by the @damage groove of the line membrane. - This can lead to dangerous situations such as explosions due to ignition lungs, or low purity products such as caustic soda in the cathode chamber. [
Therefore, it is essential to easily and quickly detect damage to ion exchange membranes.

［問題を解決するための手段］ 本発明者等はｈ　Ｈｉ’、問題に対して、イオン交換膜
の破損検知方法について検討した結果、イオン交換膜を
装着１ノか電解装を解体することなく、該電解槽に電流
を流した状態で、単一電解槽の電Ｙ（を測定し、該電夏
七がＩＬ常時の値より１０％以上に低ｔ“した場合には
、該イオン交換膜の破損が確実であることを見出し、本
発明ｔ？提案するに至った。[Means for Solving the Problem] The present inventors investigated a method for detecting damage to an ion exchange membrane to solve the problem. , Measure the electric current (Y) of a single electrolytic cell with a current flowing through the electrolytic cell, and if the electric current is 10% or more lower than the usual IL value, the ion exchange membrane It was discovered that damage to the metal is certain, and the present invention was proposed.

１１＋１も、本発明はイオン交換腔電解槽に電流な通じ
た状態°Ｃ，該電斬槽を構成する申１ａ電解槽の電圧が
正常時の電１＋：の１（）％以１−．低ドしているか否
かを測定することを特徴とするイオン交換膜の破損検知
方法゛Ｖある。11+1, the present invention is also applicable to the state in which no current is passed through the ion exchange chamber electrolytic cell, and the voltage of the 1a electrolytic cell constituting the electrolytic cell is 1()% or more of the normal voltage 1+:1-. There is a method for detecting damage to an ion exchange membrane, which is characterized by measuring whether or not the ion exchange membrane is low in temperature.

本発明は、イオン交換膜を装着した電解槽に食塩水およ
び苛性ソーダ溶液などの電解液を満した状態にして、電
流、一般には微小電流を通じ、それに対する単位電解槽
の電圧変化を測定することが特徴で、仮に該イオン交換
膜が一部にピンホール等の破損部分本有する場合には、
陽極液と陰極液の分解が不完全なため電極電位が変化し
、測定ず電１＋は＋Ｆ、常時の１０％以−Ｌ低下する。The present invention allows an electrolytic cell equipped with an ion-exchange membrane to be filled with an electrolytic solution such as a saline solution or a caustic soda solution, and then a current, generally a minute current, is passed through the electrolytic cell, and the voltage change of the unit electrolytic cell in response to the electric current is measured. As a characteristic, if the ion exchange membrane has some damaged parts such as pinholes,
Due to incomplete decomposition of the anolyte and catholyte, the electrode potential changes, and the measured voltage 1+ is +F, which is 10% or more lower than usual -L.

他方、イオン交換膜乞こピンホール等の破損部分が存在
しない場合には、電１Ｐｆｉ電（）７が変化しないため
に測定する電化に変動が認められない。（１Ｆ常時の状
ｎを保つ） このような電圧変化の測定によりイオン交換膜の破損の
有無を検知することが７７きる。On the other hand, if there is no damaged part such as a pinhole in the ion exchange membrane, no change is observed in the measured electrification because the electric current 1Pfi electric ()7 does not change. (1F constant state n is maintained) By measuring such voltage changes, it is possible to detect whether or not the ion exchange membrane is damaged.

木切＋ｍ＊において、正常時の電圧の１０％以上低下し
たか否かを測定する方法は特に制限されない。一般には
同形状の新しいイオン交換膜を用いて、予め通電した時
の電圧に対比する方法、あるいは後述するような双極式
フィルタープレス型電解槽下は、複数の甲、（ｊ７電解
糟の各単位電解槽の電（上をプロットして１！〕・た曲
線より対比する方法、等が用いられる。この際、電ｌ（
の変動幅が１Ｆ、常時の１０％より小さい場合には、ノ
イズ等の影響も考λられるため明確な検知方法とならな
い。ψ）ちるＡハこの場合外単位電解槽の陽極室側及び
陰極室側に供給する液の成分は同一・である。There is no particular restriction on the method of measuring whether the voltage has decreased by 10% or more of the normal voltage in Kikiri+m*. In general, a new ion exchange membrane of the same shape is used and the voltage is compared with the voltage when energized in advance. A method is used, such as comparing the voltage of the electrolytic cell (by plotting the above and comparing it with the curve 1!).In this case, the voltage 1 (
If the fluctuation range is smaller than 1F or 10% of normal, the influence of noise etc. may be considered, so it is not a clear detection method. ψ) Chiru A C In this case, the components of the liquid supplied to the anode chamber side and the cathode chamber side of the outer unit electrolytic cell are the same.

本発明はモノポーラ型電解槽、あるいはバイポーラ型電
解槽のいずれにおいて略）連用することができる。The present invention can be used continuously in either a monopolar electrolytic cell or a bipolar electrolytic cell.

本発明は工業的規模の電解槽に用いるイオン交換膜の一
部にピンホール等が生じて破損した場合を検知する１」
的ζｌ好ましく用いられる。即ち、１ｍ２以りのイオン
交換膜において、０．０１１１１１１Ｆ以トの破損を検
知するに迦する方法である。従って、電解槽に通しるｔ
Ｒ流は例えば、正常運転時のように余り高すぎることは
、陽極液と陰極液の分解が不完全下あってψ）電極電位
の変化が明確でない場合も生じるため好ましくなく、該
電位変化を明確にするためには微小通電状態、又はわず
かに食塩電解が起こるＰｉ！度の通電状態、即ち、０．
５〜１０００　Ａ／ｒｒｉ”程度が好ましく、特に１．
０〜４０Ａ／−が好ましい。この状態は、一般に電解停
止ヒ時における電解槽の保護のために流す電流とほぼ一
致するため、本発明の方法はこの時期に行うことが好ま
しい。The present invention detects when a pinhole or the like occurs in a part of an ion exchange membrane used in an industrial-scale electrolytic cell and is damaged.
ζl is preferably used. That is, this is a method that can detect damage of 0.0111111 F or more in an ion exchange membrane of 1 m2 or more. Therefore, t passing through the electrolytic cell
For example, if the R flow is too high as in normal operation, the decomposition of the anolyte and catholyte may be incomplete and the change in electrode potential may not be clear (ψ), which is undesirable. To clarify, Pi! is a microcurrent state, or a slight salt electrolysis occurs. The energization state is 0.
It is preferably about 5 to 1000 A/rri'', especially 1.
0 to 40 A/- is preferable. Since this state generally corresponds to the current applied to protect the electrolytic cell when electrolysis is stopped, it is preferable to carry out the method of the present invention at this time.

以ｒ、本発明の方法を双極式フィルタープレス型電解槽
にｍｍした場合を例にとって詳細に説明する。Hereinafter, the method of the present invention will be explained in detail by taking as an example the case where the method is applied to a bipolar filter press type electrolytic cell.

このタイプの電解槽は、隔壁を挟んで、その両側に子れ
ヂれ陽極及び陰極が存在１ノ陥壁を貫通して両電極が、
電気的に接続された構造を有する電解槽枠を、イオン交
換膜を介して複数個、例えば２０個以ト、液が洩れない
ように直列に並べ、その両末端に陽極室及び陰極室を夫
々存在させ、それらへ電源より給電する。従って、各単
位電解槽は電気的に直列に接続される。この場合−個の
電解槽枠は一つのΦ位電解槽の陽極室部分と隣の単位電
解槽の陰極室部分とになる。また、単位電解槽の給、排
液口は夫々共通のへラダーと、並列に、清快給管及び液
排出管で接続される。即ち各単位電解槽は、電気的に直
列に、また電解質溶液は、並列に接続されることになる
。This type of electrolytic cell has a recessed anode and a cathode on both sides of the partition, with both electrodes penetrating through the recessed wall.
A plurality of electrolytic cell frames having an electrically connected structure, for example, 20 or more, are arranged in series with an ion exchange membrane interposed therebetween to prevent liquid from leaking, and an anode chamber and a cathode chamber are respectively provided at both ends of the electrolytic cell frames. exist and supply power to them from the power supply. Therefore, each unit electrolytic cell is electrically connected in series. In this case, the - electrolytic cell frames serve as the anode chamber portion of one Φ position electrolytic cell and the cathode chamber portion of the adjacent unit electrolytic cell. In addition, the supply and drain ports of the unit electrolytic cells are respectively connected to a common ladder in parallel through a cleaning supply pipe and a liquid discharge pipe. That is, each unit electrolytic cell is electrically connected in series, and the electrolyte solution is connected in parallel.

第１図は電解槽を組立てた図であって、各単位電解槽Ｃ
Ｉ＋　　Ｃ２・・・・・・ＣＮ　／２　　＊　　ＣＭ　
　／ｚ＋＋・・・・・・ＣＮ１゜ＣＮとＮ個で構成され
°Ｃいる。Figure 1 is a diagram showing the assembled electrolytic cell, with each unit electrolytic cell C
I+ C2...CN/2 *CM
/z++...CN1°C is composed of CN and N pieces.

また険檎室液用及び隅棟室液用の各船、排液用の２本の
ヘッダー（１（Ｌ／、第１図では各１木ずつのみ示す）
Ｈから各単位電解槽の陽極室及び陰極室へ夫々パイプ１
によって接続している。通常、通電時には、矢印（ａ）
の如く電気が渣れ、通電を行うが同時にＣ，−ｃ、、／
！　　の単位電解槽においては矢印（ｂ）の如くヘッダ
ーに向けて流れる。In addition, there are two headers (1 (L/, only one each is shown in Figure 1) for each ship for liquid in the cavernous chamber and for liquid in the corner chamber, and two headers for drainage.
Pipe 1 from H to the anode chamber and cathode chamber of each unit electrolytic cell, respectively.
connected by. Normally, when energizing, arrow (a)
The electricity stagnates as in , and the current is turned on, but at the same time C, -c, , /
! In the unit electrolytic cell, the flow flows toward the header as shown by the arrow (b).

またＣＮ／ｚ＋１〜ＣＮの中位電解槽にあっては矢印（
Ｃ）の如くヘッダーから各単４０電解糟に向かって電流
が流れる所謂漏洩電流もある。In addition, for intermediate electrolyzers from CN/z+1 to CN, arrows (
There is also a so-called leakage current in which current flows from the header to each AAA cell as shown in C).

従って、通常電解槽に＊電すれば、電解槽内では中央部
の単位電解槽の電１七が最も低くなる。（第２図） このような電解槽において、ｌ少）電流を流した状態で
、各単位電解槽の電圧を測定し、前述の如く電圧の異常
よりイオン交換膜の破損を検知する。単位電解槽の極Ｉ
ｌｌ電位の測定は、例えば金属電解槽枠の場合には、測
定しようとする単位電解槽の例オば液供給（ヘッダー）
ノズル間の電圧と（）て容具に測定１ノ得るし、場合に
よっては各車枠から測定端子な出しておりば容具に行い
得る。Therefore, when electricity is normally applied to an electrolytic cell, the electric power 17 of the central unit electrolytic cell is the lowest in the electrolytic cell. (FIG. 2) In such an electrolytic cell, the voltage of each unit electrolytic cell is measured with a small current flowing, and damage to the ion exchange membrane is detected from an abnormality in voltage as described above. Unit electrolytic cell pole I
For example, in the case of a metal electrolytic cell frame, the measurement of the potential can be carried out using the liquid supply (header) of the unit electrolytic cell to be measured.
You can measure the voltage between the nozzles on the container, and depending on the situation, you can also measure the voltage on the container if there are measurement terminals coming out from each car frame.

［効果］ 本発明によれば、イオン交換収電１１槽の解体を行うこ
となｔノに容具に実施することができるため、電解槽を
絹込んだ後、または電解槽の解体の前にイオン交換膜の
状況把握を行うに適する。[Effects] According to the present invention, it is possible to carry out the process on the container without dismantling the ion-exchange electricity collection tank 11, so the process can be carried out after the electrolytic cell is inserted or before the electrolytic cell is dismantled. Suitable for understanding the status of ion exchange membranes.

「実施例］ 以下、本発明の実施例をボす。"Example] Examples of the present invention will be described below.

実施例１ 第１図に不すようなバイポーラ型電解槽（＊槽：４０対
）炎用いて食塩水の電解を行った後、陽檎液（ＮａＣＩ
２６ｗｔ、％）、及び陰１ＩＩｉ液（ＮａＯＨ３２ｗ　
ｔ％）を張った状態（液温；１５℃）で電流密度１．Ｉ
Ａ／ｒｒ１２で通電し、各単位電解槽の電圧を測定した
。その結果、第３図に示すようなグラフが得られ、２２
対目の電解槽の電圧が低いことがわかったので、該１膜
の所だけ電槽を■き膜の交換を１工っか。Example 1 After electrolyzing saline solution using a bipolar electrolytic cell (*tank: 40 pairs) flame as shown in Fig.
26wt, %), and anion 1IIIi solution (NaOH32w
t%) under tension (liquid temperature: 15°C) at a current density of 1. I
Electricity was applied at A/rr of 12, and the voltage of each unit electrolytic cell was measured. As a result, a graph as shown in Figure 3 was obtained, and 22
I found that the voltage in the opposite electrolytic cell was low, so I removed the cell at that one membrane and replaced the membrane in one step.

撤去した膜をチェックしたところ、膜にひつかきキズに
よるピンホールが発す、された。When the removed membrane was checked, it was found that there were pinholes in the membrane due to scratches.

４、図−Ｈｇ）簡単な書、明 第１図は本発明方法を適用するために用いられる双極式
フィルタープレス型電解槽の組立て図°Ｃｔｈす、第２
図及び第３図は第１図の市１解槽を構成する各Φ８位電
Ｍ槽の電圧分布状態をポすモデル図である。4. Figure-Hg) Simple text; Figure 1 is an assembly diagram of a bipolar filter press type electrolytic cell used to apply the method of the present invention °Cth, Figure 2
The figure and FIG. 3 are model diagrams showing the voltage distribution state of each Φ8 position M tank constituting the city 1 disassembly tank in FIG. 1.

図中１は、パイプ（ヘッダーと咎単位電、解槽となつな
ぐ配管）　、Ｃｏ　Ｃ２＊　Ｃ３’・・・・・ＣＮ／２
　・・・・・・Ｃべ−１及びＣＮはいずれも鴫Ｓ位電解
槽、１１はヘッダーで、ｌはパイプ（配管）−’ｐｔｈ
ｉ。1 in the figure is the pipe (piping connecting the header, unit electrolyzer, and electrolysis tank), Co C2* C3'...CN/2
・・・・・・C base 1 and CN are both electrolytic tanks, 11 is a header, l is a pipe (piping)-'pth
i.

Claims (2)

【特許請求の範囲】[Claims] （１）イオン交換膜電解槽に電流を流した状態で、該電
解槽を構成する単位電解槽の電圧が、正常時の１０％以
上に低下しているか否かを測定することを特徴とするイ
オン交換膜の破損検知方法。(1) It is characterized by measuring whether or not the voltage of the unit electrolytic cells constituting the electrolytic cell has decreased to 10% or more of the normal voltage while a current is flowing through the ion exchange membrane electrolytic cell. Method for detecting damage to ion exchange membranes. （２）電流が１．０〜４０Ａ／ｍ＾２の微小電流である
特許請求の範囲第１項記載の方法。(2) The method according to claim 1, wherein the current is a minute current of 1.0 to 40 A/m^2.