JP2005061975A - Electric conductivity measuring cell and method of measuring the same - Google Patents
Electric conductivity measuring cell and method of measuring the same Download PDFInfo
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- JP2005061975A JP2005061975A JP2003291864A JP2003291864A JP2005061975A JP 2005061975 A JP2005061975 A JP 2005061975A JP 2003291864 A JP2003291864 A JP 2003291864A JP 2003291864 A JP2003291864 A JP 2003291864A JP 2005061975 A JP2005061975 A JP 2005061975A
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- 238000000034 method Methods 0.000 title claims abstract description 20
- 239000012530 fluid Substances 0.000 claims abstract description 39
- 238000005259 measurement Methods 0.000 claims description 32
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical group [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 claims description 5
- 238000011065 in-situ storage Methods 0.000 claims description 3
- 238000000691 measurement method Methods 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 18
- 238000012625 in-situ measurement Methods 0.000 abstract description 12
- 239000012429 reaction media Substances 0.000 abstract description 6
- 239000007788 liquid Substances 0.000 abstract description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 26
- 239000000523 sample Substances 0.000 description 15
- 239000001569 carbon dioxide Substances 0.000 description 13
- 229910002092 carbon dioxide Inorganic materials 0.000 description 13
- 239000002608 ionic liquid Substances 0.000 description 12
- 239000004696 Poly ether ether ketone Substances 0.000 description 11
- 229920002530 polyetherether ketone Polymers 0.000 description 11
- 239000011521 glass Substances 0.000 description 5
- 238000011161 development Methods 0.000 description 4
- 230000018109 developmental process Effects 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000009434 installation Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000002848 electrochemical method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012800 visualization Methods 0.000 description 1
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- Measurement Of Resistance Or Impedance (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
本発明は、高温・高圧の反応器中を直接観察可能なその場測定装置に関するものであり
、更に詳しくは、高温・高圧の超臨界流体を反応媒体として利用した化学反応プロセスに
おける反応流体の電気伝導度をその場測定により高精度で測定することを可能とする新規
高圧電気伝導度測定セルに関するものである。
近年、水や二酸化炭素を主成分とした超臨界流体は、従来の流体溶媒にない多くの特徴
や利点を有し、環境調和型プロセスの媒体として注目を集めているが、本発明は、上記超
臨界流体を反応媒体とする次世代の化学反応プロセスとしてその実用化が強く期待されて
いる超臨界流体の技術分野において、高温・高圧反応系の反応流体の電気伝導度をその場
測定により測定することを可能とする新しいタイプの電気伝導度測定セルを提供するもの
として有用である。
The present invention relates to an in-situ measurement apparatus that can directly observe inside a high-temperature / high-pressure reactor, and more specifically, to a chemical reaction process using a high-temperature / high-pressure supercritical fluid as a reaction medium.
The present invention relates to a novel high-pressure electrical conductivity measuring cell that can measure the electrical conductivity of a reaction fluid with high accuracy by in-situ measurement.
In recent years, supercritical fluids mainly composed of water and carbon dioxide have many features and advantages not found in conventional fluid solvents, and are attracting attention as media for environmentally conscious processes. In the technical field of supercritical fluid, which is expected to be put to practical use as a next-generation chemical reaction process using supercritical fluid as a reaction medium, the electrical conductivity of the reaction fluid in high-temperature and high-pressure reaction systems is measured by in-situ measurement. It is useful to provide a new type of conductivity measuring cell that can be used.
従来、電気伝導度は、例えば、水溶液中で移動可能なイオン濃度を測定するための尺度
として広く用いられている。一般に、電気伝導度は、電源からの電流供給用電極と検出用
電極との間の抵抗値を測定し、それにより、被測定水溶液中のイオン濃度の増減を検出す
る方法で測定される。従来の電気伝導度測定装置では、例えば、被測定物質の状態や電極
の状態、測定時の雰囲気温度及び圧力条件等に応じて、その電気伝導度測定装置の測定レ
ンジを調整した後、測定が実行される。電気伝導度を正確かつ精密に測定するためには、
二つの電極の表面積及び距離を保持してセル定数を一定として、それらの電極を被測定対
象である流体試料中の適切な位置に設置する必要がある。従来、この種の電気伝導度測定
セルとして、例えば、ガラス管に電極を溶着し、そのガラス管内にリード線を通して伝導
度計へ接続するセルが開発されている（例えば、非特許文献１）。
Conventionally, electrical conductivity has been widely used as a measure for measuring the concentration of ions that can move in an aqueous solution, for example. In general, the electrical conductivity is measured by a method of measuring a resistance value between a current supply electrode from a power source and a detection electrode, and thereby detecting an increase or decrease in ion concentration in the aqueous solution to be measured. In a conventional electrical conductivity measurement device, for example, after adjusting the measurement range of the electrical conductivity measurement device according to the state of the substance to be measured, the state of the electrode, the atmospheric temperature and pressure conditions at the time of measurement, etc., the measurement is performed. Executed. To measure electrical conductivity accurately and precisely,
It is necessary to keep the surface area and distance of the two electrodes and to make the cell constant constant, and to place these electrodes at appropriate positions in the fluid sample to be measured. Conventionally, as this type of electrical conductivity measurement cell, for example, a cell has been developed in which an electrode is welded to a glass tube and connected to a conductivity meter through a lead wire in the glass tube (for example, Non-Patent Document 1).
しかしながら、これらの装置を高温・高圧の反応器中を直接観察可能なその場測定装置
として使用する場合、例えば、従来のガラス製チューブを用いたセルでは、気密を保つシ
ールや耐圧性の点で問題がある。気密性や耐圧性を保持可能なガラス製セルやテフロン（
登録商標）製セル等（例えば、非特許文献２）も開発されているが、これらのセルでは、
内圧が高圧で外圧が常圧となるため、電極間の距離などが変化し、各測定条件下における
セル定数の補正が必要となり、簡便に高圧条件下で電気伝導度を測定することは困難であ
った。また、これらのセルを用いて、多相系の流体試料において任意の相の電気伝導度を
測定することは困難であった。
However, when these devices are used as in-situ measuring devices that can directly observe the inside of a high-temperature and high-pressure reactor, for example, in a cell using a conventional glass tube, it is possible to maintain an airtight seal and pressure resistance. There's a problem. Glass cells and Teflon that can maintain airtightness and pressure resistance (
(Registered trademark) cells and the like (for example, Non-Patent Document 2) have also been developed.
Since the internal pressure is high and the external pressure is normal pressure, the distance between electrodes changes, and it is necessary to correct the cell constant under each measurement condition. It is difficult to easily measure the electrical conductivity under high pressure conditions. there were. Moreover, it has been difficult to measure the electrical conductivity of an arbitrary phase in a multiphase fluid sample using these cells.
また、従来、電気伝導度測定セルを設置する方法として、例えば、少なくとも２個の電
極を有する電気伝導度測定セルを、送給されてくる試料に順に接するように試料測定流路
中に２個直列に配置したイオン濃度測定装置（特許文献１）、被測定物質に接する少なく
とも２個の電極を有する電気伝導度測定セルを少なくとも２個有する多元電気伝導度測定
装置（特許文献２）、等が提案されている。更に、従来、電気伝導度測定用電極を設置す
る方法として、電極を溶着した板を複数の棒でねじ止めして、それらを高圧容器内の所定
の箇所に固定する方式（例えば、非特許文献３）が採用されている。この種の方式では、
セルの内部及び外部で差圧がなく、電極を固定する部材に力が加わらず、セル定数はあま
り変化しない。しかし、これらの電極の固定方法は、部品点数が多く、装置が複雑であり
、容器内において電極の位置を簡便に変えることは困難であった。異なる流体試料の測定
では、適当かつ異なるセル定数を有する電極が必要であり、簡便にそれらの変更が可能な
電極の固定方式の改善が強く求められていた。
Conventionally, as a method of installing an electrical conductivity measurement cell, for example, two electrical conductivity measurement cells having at least two electrodes are provided in the sample measurement flow path so as to be in contact with the supplied sample in order. An ion concentration measuring device (Patent Document 1) arranged in series, a multi-element electric conductivity measuring device (Patent Document 2) having at least two electric conductivity measuring cells having at least two electrodes in contact with a substance to be measured, etc. Proposed. Furthermore, conventionally, as a method of installing an electrode for measuring electrical conductivity, a method in which a plate on which an electrode is welded is screwed with a plurality of rods, and these are fixed to a predetermined location in a high-pressure vessel (for example, non-patent document) 3) is adopted. In this type of scheme,
There is no differential pressure inside and outside the cell, no force is applied to the member fixing the electrode, and the cell constant does not change much. However, these electrode fixing methods have a large number of parts and a complicated apparatus, and it has been difficult to easily change the position of the electrode in the container. Measurement of different fluid samples requires electrodes having appropriate and different cell constants, and there has been a strong demand for an improved electrode fixing method that can be easily changed.
一方、水や二酸化炭素を主成分とした超臨界流体は、従来の液体溶媒にない多くの特徴
や利点を有し、環境調和型プロセスの媒体として注目を集めている。本発明者らは、これ
まで、化学合成プロセスの構築を目的として、高温・高圧の反応器中を直接観察可能なそ
の場測定装置の開発ならびに超臨界流体の溶媒機能の解明を行ってきたが、上記化学合成
プロセスを実現するためには、例えば、（ｉ）電気化学測定が可能なその場測定セルの開
発、（ｉｉ）超臨界水に対応した高温・高圧ＮＭＲプローブの開発などを中心として、特
に、高温・高圧の化学反応系におけるその場測定を可能とする各種測定装置の開発が不可
欠である。しかし、これまで、高温・高圧の反応器中を直接観察可能なその場測定装置の
開発は限られており、当技術分野においては、高圧の反応場で、反応流体の任意の位置に
おける電気伝導度を簡便に、しかも高精度で測定することができる装置の開発が強く要請
されていた。
On the other hand, supercritical fluids mainly composed of water and carbon dioxide have many features and advantages not found in conventional liquid solvents, and are attracting attention as media for environmentally conscious processes. The inventors of the present invention have so far developed an in-situ measuring device that can directly observe the inside of a high-temperature / high-pressure reactor and elucidated the solvent function of a supercritical fluid for the purpose of establishing a chemical synthesis process. In order to realize the above-mentioned chemical synthesis process, for example, (i) development of an in-situ measurement cell capable of electrochemical measurement, (ii) development of a high temperature / high pressure NMR probe corresponding to supercritical water, etc. In particular, it is essential to develop various measuring devices that enable in-situ measurement in high-temperature and high-pressure chemical reaction systems. However, until now, there have been limited developments of in-situ measurement devices that can directly observe the inside of a high-temperature and high-pressure reactor. In this technical field, electric conduction at any position of a reaction fluid in a high-pressure reaction field is limited. There has been a strong demand for the development of an apparatus that can measure the degree of measurement simply and with high accuracy.
このような状況の中で、本発明者らは、上記従来技術に鑑みて、高温・高圧の超臨界流
体を反応媒体として利用した化学反応プロセスにおいて、反応流体の電気化学的状態を直
接観察可能なその場測定による高圧電気伝導度測定セルを開発することを目標として鋭意
研究を積み重ねた結果、流体試料の出入りが可能なチューブ状からなる電極固定用ホルダ
ーを使用することにより、高圧での電気伝導度測定でもセル定数がほとんど変化しない新
しい高圧電気伝導度測定セルが得られることを見出し、本発明を完成するに至った。
即ち、本発明は、高温・高圧の反応器中を直接観察可能なその場測定用の高圧電気伝導
度測定セルを提供することを目的とするものである。
また、一般に、高圧での電気伝導度測定ではセル定数の補正を各圧力条件で行う必要が
あったが、本発明は、各圧力条件においてもセル定数がほとんど変化しない新しいタイプ
の高圧電気伝導度測定セルを提供することを目的とするものである。
Under such circumstances, the present inventors can directly observe the electrochemical state of the reaction fluid in a chemical reaction process using a high-temperature, high-pressure supercritical fluid as a reaction medium in view of the above-described conventional technology. As a result of intensive research aimed at developing a high-pressure electrical conductivity measurement cell by in-situ measurement, the use of a tube-shaped electrode fixing holder that allows fluid samples to enter and exit can be used. It has been found that a new high-voltage electrical conductivity measurement cell can be obtained in which the cell constant hardly changes even in the conductivity measurement, and the present invention has been completed.
That is, an object of the present invention is to provide a high-pressure electrical conductivity measuring cell for in-situ measurement that can directly observe the inside of a high-temperature and high-pressure reactor.
In general, in the measurement of electrical conductivity at high pressure, it was necessary to correct the cell constant under each pressure condition. However, the present invention is a new type of high-voltage electrical conductivity in which the cell constant hardly changes even under each pressure condition. The object is to provide a measuring cell.
上記課題を解決するための本発明は、以下の技術的手段から構成される。
（１）電気伝導度測定を行うための電極固定用部材であって、チューブ状の電極固定用ホ
ルダー、該チューブの両端に形成した２枚の電極、該電極に接続されたリード線を有し、
該チューブ側面にチューブ内外の試料流体の出入りを可能とする空間を有することを特徴
とする電気伝導度測定用電極固定用部材。
（２）チューブの両端に位置する２枚の電極をキャップにより固定したことを特徴とする
前記（１）に記載の電気伝導度測定用電極固定用部材。
（３）チューブ側面に、チューブ内外の試料流体の出入りを可能とする複数の穴を設けた
ことを特徴とする前記（１）に記載の電気伝導度測定用電極固定用部材。
（４）非伝導性の板を２枚の電極表面の片方もしくは両方に設置することで、電極の表面
積を変更可能としたことを特徴とする前記（１）から（３）のいずれか１項に記載の電気
伝導度測定用電極固定用部材。
（５）前記（１）から（４）のいずれか１項に記載のチューブで固定された電極一式を高
圧セルにセットしたことを特徴とする電気伝導度測定セル。
（６）前記（５）に記載のチューブ状の電極固定用ホルダーを有する電気伝導度測定セル
を使用し、超臨界流体などの高温・高圧の流体試料の電気伝導度を高温・高圧下でその場
測定することを特徴とする電気伝導度測定方法。
（７）電極一式の位置を変更することで、均一系又は多相系の流体試料の任意の相の電気
伝導度を測定することを特徴とする前記（５）に記載の電気伝導度測定方法。
（８）ホルダーとなるチューブの内径と長さを変更することにより、セル定数を任意に変
更することを特徴とする前記（６）に記載の電気伝導度測定方法。
The present invention for solving the above-described problems comprises the following technical means.
(1) An electrode fixing member for measuring electrical conductivity, having a tube-shaped electrode fixing holder, two electrodes formed at both ends of the tube, and a lead wire connected to the electrode ,
A member for fixing an electrode for measuring electrical conductivity, characterized in that it has a space on the side of the tube that allows sample fluid inside and outside the tube to enter and exit.
(2) The electrode fixing member for measuring electrical conductivity according to (1) above, wherein two electrodes positioned at both ends of the tube are fixed with caps.
(3) The electrode fixing member for measuring conductivity according to (1) above, wherein a plurality of holes that allow sample fluid inside and outside the tube to enter and exit are provided on a side surface of the tube.
(4) Any one of (1) to (3) above, wherein the surface area of the electrode can be changed by installing a nonconductive plate on one or both of the two electrode surfaces. 2. An electrode fixing member for measuring electrical conductivity according to 1.
(5) An electric conductivity measuring cell, wherein a set of electrodes fixed by the tube according to any one of (1) to (4) is set in a high-pressure cell.
(6) Using the electrical conductivity measurement cell having the tube-shaped electrode fixing holder described in (5) above, the electrical conductivity of a high-temperature / high-pressure fluid sample such as a supercritical fluid is measured at high temperature / high pressure. A method for measuring electrical conductivity, characterized by performing field measurement.
(7) The electrical conductivity measurement method according to (5), wherein the electrical conductivity of an arbitrary phase of a homogeneous or multiphase fluid sample is measured by changing the position of the set of electrodes. .
(8) The method for measuring electrical conductivity according to (6), wherein the cell constant is arbitrarily changed by changing the inner diameter and length of a tube serving as a holder.
次に、本発明について更に詳細に説明する。
本発明は、高温高圧の超臨界流体を反応媒体として用いた化学反応プロセスにおいて、
反応流体の電気伝導度を直接測定可能なその場測定により測定することを可能とする高圧
電気伝導度測定装置に係るものである。
本発明の高圧電気伝導度測定セルの電極固定用ホルダーの好適な一例を図１に示す。本
発明のその場測定セルの電極固定用ホルダーの材料は、耐薬品製に優れ、加工性や耐圧性
が良好なものが適当である。即ち、本発明では、ポリエーテルエーテルケトン（ＰＥＥＫ
）を用いて電極固定用ホルダーを作製し、高圧電気伝導度測定セルの設計・製作を行うこ
とが好ましい。図１に示した通り、本発明では、好適には、例えば、２枚のＰｔ電極はＰ
ＥＥＫチューブの両端に位置し、キャップにより固定される。Ｐｔ電極からの被覆リード
線はキャップを介して伝導度計へと接続される。このＰＥＥＫチューブで固定されたＰｔ
電極一式を窓付きの高圧セルにセットして高圧電気伝導度測定セルが作製される。
Next, the present invention will be described in more detail.
The present invention is a chemical reaction process using a high-temperature and high-pressure supercritical fluid as a reaction medium.
The present invention relates to a high-pressure electrical conductivity measuring apparatus that enables measurement by in-situ measurement capable of directly measuring the electrical conductivity of a reaction fluid.
A preferred example of the electrode fixing holder of the high voltage electrical conductivity measurement cell of the present invention is shown in FIG. As the material for the electrode fixing holder of the in-situ measurement cell of the present invention, a material excellent in chemical resistance and having good workability and pressure resistance is suitable. That is, in the present invention, polyetheretherketone (PEEK)
It is preferable to design and manufacture a high-voltage electrical conductivity measuring cell by preparing a holder for fixing an electrode using As shown in FIG. 1, in the present invention, for example, two Pt electrodes are preferably P
Located at both ends of the EEK tube and fixed by caps. The coated lead from the Pt electrode is connected to the conductivity meter through a cap. Pt fixed with this PEEK tube
A set of electrodes is set in a high voltage cell with a window to produce a high voltage electrical conductivity measuring cell.
次に、電極固定用ホルダーを更に詳しく説明する。ＰＥＥＫ製の電極固定用ホルダーは
、任意の内径及び長さのチューブから製作され、そのチューブ側面には複数の穴が開けら
れている。このチューブ側面の穴は、流体試料の出入りを可能とするものであり、伝導度
セル内における流体試料の組成の変化や混合過程、及び反応などの変化を随時観測可能と
する。チューブ側面の穴のサイズは、粘性率が高い流体試料では、大きい方が出入りが円
滑となり好ましい。また、チューブ側面の穴はチューブ側面を貫通するように対称的に複
数設けた方が、流体試料の出入りが円滑となり好ましい。一方、チューブの内径は、設置
される電極の直径の最大値を決定するものであり、一般に、電気伝導度が低い流体試料の
測定では大きい方が好ましく、電気伝導度が高い流体試料の測定では小さい方が好ましい
。図２に示したとおり、任意のセル定数を有する電極固定用のホルダーが製作可能である
。また、ＰＥＥＫ製チューブの変更を行わなくとも電極の表面積を変化させてセル定数の
変更が可能となるように、非伝導製のドーナツ状の円板が電極表面に設置可能となってい
る。例えば、内径が直径１０ｍｍで長さ１５ｍｍのＰＥＥＫ製チューブからなる電極では
、セル定数は１．７２ｃｍ-1である。また、内径が直径５ｍｍで長さ１５ｍｍのＰＥＥＫ
製チューブからなる電極では、セル定数は４．９６ｃｍ-1である。一方、内径が直径１０
ｍｍで長さ１５ｍｍのＰＥＥＫ製チューブの電極表面に直径５ｍｍのドーナツ状の円板を
被せた電極では、円板がないときの約３倍近いセル定数の値が得られている。
Next, the electrode fixing holder will be described in more detail. The electrode fixing holder made of PEEK is manufactured from a tube having an arbitrary inner diameter and length, and a plurality of holes are formed on the side surface of the tube. The hole on the side surface of the tube allows the fluid sample to enter and exit, and allows the change in the composition of the fluid sample, the mixing process, and the reaction in the conductivity cell to be observed as needed. As for the size of the hole on the side of the tube, in the case of a fluid sample having a high viscosity, a larger one is preferable because it allows smooth entry and exit. In addition, it is preferable to provide a plurality of holes on the side of the tube symmetrically so as to penetrate the side of the tube because the fluid sample can enter and exit smoothly. On the other hand, the inner diameter of the tube determines the maximum value of the diameter of the electrode to be installed, and in general, it is preferable to measure a fluid sample with low electrical conductivity, and for measuring a fluid sample with high electrical conductivity. Smaller is preferable. As shown in FIG. 2, an electrode fixing holder having an arbitrary cell constant can be manufactured. Further, a non-conductive donut-shaped disk can be installed on the electrode surface so that the cell constant can be changed by changing the surface area of the electrode without changing the PEEK tube. For example, in an electrode made of a PEEK tube having an inner diameter of 10 mm and a length of 15 mm, the cell constant is 1.72 cm −1 . PEEK with an inner diameter of 5 mm and a length of 15 mm
In an electrode made of a tube made, the cell constant is 4.96 cm −1 . On the other hand, the inner diameter is 10
In the case of an electrode in which a 5 mm diameter donut-shaped disk is covered on the electrode surface of a PEEK tube having a length of 15 mm and a length of 15 mm, the value of the cell constant is about three times that when there is no disk.
一般に、高圧での電気伝導度測定ではセル定数の補正を各圧力条件で行わなければなら
ないが、本発明の高圧電気伝導度測定セルでは、ＰＥＥＫ製ホルダーの内外で差圧が生じ
ないため、セル定数はあまり変化せず、加圧実験の前後においてもほぼ一致した値を示す
。また、本発明の高圧電気伝導度測定セルは、Ｐｔ電極の設置方法などの工夫により、均
一系ならびに多相系の実験に用いることが可能である。尚、後記する実施例では、超臨界
二酸化炭素とイオン性液体からなる二相系において、イオン性液体の電気伝導度が二酸化
炭素の加圧に伴いどのように変化するかについて説明する。
In general, in the measurement of electric conductivity at high pressure, the cell constant must be corrected under each pressure condition. However, in the high-pressure conductivity measuring cell of the present invention, there is no difference in pressure between the inside and outside of the PEEK holder. The constant does not change so much and shows almost the same value before and after the pressurization experiment. In addition, the high-voltage electrical conductivity measurement cell of the present invention can be used for homogeneous and multiphase experiments by devising the installation method of the Pt electrode. In the examples described later, how the electrical conductivity of the ionic liquid changes with the pressurization of carbon dioxide in a two-phase system composed of supercritical carbon dioxide and ionic liquid will be described.
本発明は、高温・高圧の超臨界流体を反応媒体として利用する化学反応プロセスにおい
て反応流体の電気伝導度をその場測定により測定するための高圧電気伝導度測定セルに係
るものであり、本発明により、１）超臨界流体の反応系を直接観察可能な高圧電気伝導度
測定セルを提供できる、２）一般に、高圧での電気伝導度測定では、セル定数の補正を各
圧力条件で行わなければならないが、本発明の高圧電気伝導度測定セルでは、ＰＥＥＫ製
ホルダーの内外で差圧が生じないため、セル定数はほとんど変化しない、３）高圧ライン
系における設置位置を任意に変えることができる、４）ホルダーとなるチューブの内径と
長さを変更することで、自在にセル定数を変更することができる、５）電極表面に非伝導
性の板を挟み込むことによりセル定数をあげることができる、という効果が奏される。
The present invention relates to a high-pressure electrical conductivity measurement cell for measuring the electrical conductivity of a reaction fluid by in-situ measurement in a chemical reaction process using a high-temperature, high-pressure supercritical fluid as a reaction medium. 1) It is possible to provide a high-pressure electrical conductivity measurement cell capable of directly observing a reaction system of a supercritical fluid. 2) Generally, in electrical conductivity measurement at high pressure, the cell constant must be corrected under each pressure condition. However, in the high-pressure conductivity measuring cell of the present invention, since the differential pressure does not occur inside and outside the PEEK holder, the cell constant hardly changes. 3) The installation position in the high-pressure line system can be arbitrarily changed. 4) The cell constant can be changed freely by changing the inner diameter and length of the tube that serves as the holder. 5) A non-conductive plate is sandwiched between the electrode surfaces. It is possible to increase the constant, the effect is achieved that.
次に、実施例に基づいて本発明を具体的に説明するが、本発明は、以下の実施例によっ
て何ら限定されるものではない。
EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.
（１）実験装置
電気伝導度計として、（株）扶桑製作所、全自動溶液電気伝導度装置、Ｓｙｓｔｅｍ３
６９を使用した。また、高圧セルとして、日本分光製、可視化窓付き、容量約３５ｍｌを
使用した。
（２）実験方法
ＰＥＥＫ製の固定用部材を用いてＰｔ円板を固定した電極を製作し、伝導度が既知の塩
化カリウム溶液を用いて、セル定数を決定した。その電極を高圧セル内の下方に設置し、
セルが十分に漬かる量のイオン性液体を注ぎ、高圧セルの蓋を閉めた。高圧セルを４０℃
に調整した恒温水槽に入れ、電極からのリード線を電気伝導度計に接続した。イオン性液
体をアルゴンガスで脱気した後、電気抵抗の測定を行った。また、二酸化炭素を加圧後の
イオン性液体の電気抵抗の時間変化を測定した。更に、各二酸化炭素圧力条件下において
、平衡に到達したあとの、イオン性液体の電気抵抗を測定した。なお、電気伝導度は、セ
ル定数を測定で得られた電気抵抗で割ることにより求めることができる。
（３）実験結果
イオン性液体に二酸化炭素を加圧した直後からの電気抵抗の時間変化を図４に示す。図
から分かるとおり、イオン性液体は二酸化炭素の加圧、溶解により、電気抵抗が著しく減
少する、即ち、電気伝導度が顕著に増加することが分かる。また、図５に示したとおり、
その効果は二酸化炭素の圧力が高くなるほど大きいことが示された。二酸化炭素の圧力と
イオン性液体への溶解度の関係を用いれば、実験で得られる電気伝導度からイオン性液体
中の二酸化炭素の濃度を推定することなども可能である。
(1) Experimental device As electric conductivity meter, Fuso Seisakusho Co., Ltd., fully automatic solution electric conductivity device, System 3
69 was used. Moreover, as a high-pressure cell, a product made by JASCO, with a visualization window, and a capacity of about 35 ml was used.
(2) Experimental method The electrode which fixed the Pt disk using the fixing member made from PEEK was manufactured, and the cell constant was determined using the potassium chloride solution with known conductivity. Install the electrode below the high-pressure cell,
A sufficient amount of ionic liquid was poured into the cell, and the lid of the high pressure cell was closed. High pressure cell at 40 ° C
The lead wire from the electrode was connected to an electric conductivity meter. After the ionic liquid was deaerated with argon gas, the electrical resistance was measured. Moreover, the time change of the electrical resistance of the ionic liquid after pressurizing carbon dioxide was measured. Furthermore, the electric resistance of the ionic liquid after reaching equilibrium under each carbon dioxide pressure condition was measured. The electric conductivity can be obtained by dividing the cell constant by the electric resistance obtained by measurement.
(3) Experimental results FIG. 4 shows the change in electrical resistance over time immediately after pressurizing carbon dioxide into the ionic liquid. As can be seen from the figure, it can be seen that the electrical resistance of the ionic liquid is remarkably reduced by pressurizing and dissolving carbon dioxide, that is, the electrical conductivity is remarkably increased. As shown in FIG.
The effect was shown to increase as the pressure of carbon dioxide increased. If the relationship between the pressure of carbon dioxide and the solubility in ionic liquid is used, it is also possible to estimate the concentration of carbon dioxide in the ionic liquid from the electrical conductivity obtained in the experiment.
以上詳述したように、本発明は、電気伝導度測定セルに係るものであり、例えば、環境
調和型プロセスの媒体として注目を集めている、超臨界流体に対応した高圧用電気伝導度
測定用電極として有用である。本発明の電気伝導度測定用電極は、非常にコンパクトな形
状で１組のＰｔ電極を固定することが可能であり、その電極の設置方法など調整すること
で、均一系ならびに多相系のその場測定装置として利用できる。よって、本発明の電気伝
導測定セルは、生産プロセスなどにおける計測装置として利用される可能性が高い。例え
ば、本発明の電極を回分式装置内に複数設置することで、装置内の電気伝導度の空間的な
分布をリアルタイムで得ることが可能である。同様に、この電極を流通式の装置内に組み
込むことで装置内の電気伝導度の状況を把握することも可能である。特に、本発明の電極
は、電気伝導度が温度や圧力、及び組成などの要因により顕著に変化するプロセスで有効
であり、その取り扱いの容易さ、セル定数の最適化の容易さ等から、広い用途で利用され
る可能性が高いものと期待される。
As described in detail above, the present invention relates to an electrical conductivity measurement cell, for example, for measuring electrical conductivity for high pressure corresponding to a supercritical fluid, which is attracting attention as a medium for environmentally conscious processes. Useful as an electrode. The electrode for electrical conductivity measurement of the present invention can fix a pair of Pt electrodes in a very compact shape, and by adjusting the installation method of the electrodes, it can be used for homogeneous and multiphase systems. It can be used as a field measurement device. Therefore, the electrical conductivity measuring cell of the present invention is highly likely to be used as a measuring device in a production process or the like. For example, by installing a plurality of electrodes of the present invention in a batch type device, it is possible to obtain a spatial distribution of electrical conductivity in the device in real time. Similarly, it is possible to grasp the state of electrical conductivity in the apparatus by incorporating this electrode in the flow-type apparatus. In particular, the electrode of the present invention is effective in a process in which the electrical conductivity changes remarkably depending on factors such as temperature, pressure, and composition, and is wide because of its ease of handling, optimization of cell constants, etc. It is expected to be highly likely to be used in applications.
Claims (8)
ー、該チューブの両端に形成した２枚の電極、該電極に接続されたリード線を有し、該チ
ューブ側面にチューブ内外の試料流体の出入りを可能とする空間を有することを特徴とす
る電気伝導度測定用電極固定用部材。 An electrode fixing member for measuring electrical conductivity, comprising a tube-shaped electrode fixing holder, two electrodes formed at both ends of the tube, and a lead wire connected to the electrode, the tube A member for fixing an electrode for measuring electrical conductivity, characterized in that a side surface has a space that allows sample fluid inside and outside the tube to enter and exit.
項１に記載の電気伝導度測定用電極固定用部材。 2. The electrode fixing member for measuring electrical conductivity according to claim 1, wherein two electrodes positioned at both ends of the tube are fixed with caps.
を特徴とする請求項１に記載の電気伝導度測定用電極固定用部材。 2. The electrode fixing member for measuring electrical conductivity according to claim 1, wherein a plurality of holes that allow sample fluid inside and outside the tube to enter and exit are provided on a side surface of the tube.
変更可能としたことを特徴とする請求項１から３のいずれか１項に記載の電気伝導度測定
用電極固定用部材。 The electrical conductivity according to any one of claims 1 to 3, wherein the surface area of the electrode can be changed by installing a non-conductive plate on one or both of the two electrode surfaces. Electrode fixing member for measurement.
ットしたことを特徴とする電気伝導度測定セル。 An electric conductivity measuring cell, wherein a set of electrodes fixed by the tube according to any one of claims 1 to 4 is set in a high-pressure cell.
し、超臨界流体などの高温・高圧の流体試料の電気伝導度を高温・高圧下でその場測定す
ることを特徴とする電気伝導度測定方法。 Using the electrical conductivity measuring cell having the tube-shaped electrode fixing holder according to claim 5, the electrical conductivity of a high-temperature / high-pressure fluid sample such as a supercritical fluid is measured in situ under high temperature / high pressure. A method for measuring electrical conductivity.
度を測定することを特徴とする請求項５に記載の電気伝導度測定方法。 The electrical conductivity measurement method according to claim 5, wherein the electrical conductivity of an arbitrary phase of the homogeneous or multiphase fluid sample is measured by changing the position of the set of electrodes.
ることを特徴とする請求項６に記載の電気伝導度測定方法。
The electric conductivity measuring method according to claim 6, wherein the cell constant is arbitrarily changed by changing an inner diameter and a length of a tube serving as a holder.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101968511A (en) * | 2010-09-27 | 2011-02-09 | 成都理工大学 | Small electrode experiment device for measuring resistivity of mineral and solid insulating material |
| JP2012118020A (en) * | 2010-12-03 | 2012-06-21 | Maruboshi Su Kk | Pressure-resistant container sensor for measuring dielectric property |
| CN102636697A (en) * | 2012-05-11 | 2012-08-15 | 湘潭电机股份有限公司 | Device for dynamically measuring performance of insulating medium |
| CN116735666A (en) * | 2023-05-24 | 2023-09-12 | 成都理工大学 | Supercritical geothermal fluid conductivity measurement system and measurement method |
-
2003
- 2003-08-11 JP JP2003291864A patent/JP4113949B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101968511A (en) * | 2010-09-27 | 2011-02-09 | 成都理工大学 | Small electrode experiment device for measuring resistivity of mineral and solid insulating material |
| JP2012118020A (en) * | 2010-12-03 | 2012-06-21 | Maruboshi Su Kk | Pressure-resistant container sensor for measuring dielectric property |
| CN102636697A (en) * | 2012-05-11 | 2012-08-15 | 湘潭电机股份有限公司 | Device for dynamically measuring performance of insulating medium |
| CN116735666A (en) * | 2023-05-24 | 2023-09-12 | 成都理工大学 | Supercritical geothermal fluid conductivity measurement system and measurement method |
| CN116735666B (en) * | 2023-05-24 | 2024-01-12 | 成都理工大学 | Supercritical geothermal fluid conductivity measurement system and measurement method |
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