JP2011117807A - In-line apparatus and method for measurement of minute amount of moisture in organic solvent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-line apparatus and a method for measurement of a minute amount of moisture in an organic solvent, which has a simple constitution, and can efficiently and continuously measure a minute amount of moisture in an organic solvent. <P>SOLUTION: The in-line apparatus for measurement of a minute amount of moisture in an organic solvent includes: a prescribed-quantity filled tank 10 to which an organic solvent is introduced, can heat treatment to a prescribed temperature equal to the boiling point of the organic solvent or higher, and having a prescribed capacity; a solvent introducing part 1 for introducing an organic solvent to the prescribed-quantity filled tank 10; a solvent supply part 2 supplied with a heat-treated organic solvent; a solvent transfer part for transferring the organic solvent of the prescribed-quantity filled tank 10 to consumption facilities 30; a transfer channel L for transferring the organic solvent from the solvent introducing part 1 to the consumption facilities 30; a transfer quantity control part for controlling the transfer of a prescribed quantity of heat-treated organic solvent; and an analytical part 20 for measuring the organic solvent transferred from the solvent supply part 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an in-line trace moisture measuring apparatus and measuring method in an organic solvent, for example, an organic solvent such as a cleaning liquid used in a production apparatus or research facility such as a semiconductor or a solar cell, an organic solvent after use, or an organic solvent. The present invention relates to an in-line trace moisture measuring apparatus and measuring method in an organic solvent that is a raw material for a synthesis reaction or the like.

  The “organic solvent” referred to in the present application includes a solvent that is widely used industrially, for example, an organic solvent such as octane, a chlorofluorocarbon-based solvent, and a chlorine-based solvent. In particular, the present application has an aprotic property that is relatively easy to separate from nonpolar organic solvents such as n-octane and low water solubility, or polar but mixed water such as tetrahydrofuran (THF). When organic solvents, that is, "non-polar organic solvents or polar aprotic organic solvents" that are difficult to separate from water in the liquid phase but relatively easy to separate from water in the gas phase It is effective.

  Organic solvents are often used as manufacturing equipment for producing semiconductors, solar cells, etc., research facilities for developing new materials, or raw materials for various organic substances. These organic solvents often contain a small amount of water, which can greatly affect the manufacturing / research or product characteristics. in use. At this time, it is very important to accurately grasp the water concentration in the organic solvent that has been subjected to the water removal treatment. For example, the Karl Fischer titration method is generally known.

  Specifically, methylene blue is added to methanol, yellow-green methanol solvent dehydrated by Karl Fischer reagent is placed in a container with a septum, and insulating oil (organic solvent) collected with a syringe is injected into the container. To do. Shake for about 1 minute to extract the water in the insulating oil into the methanol solvent, and then leave it to separate into two layers. At this time, if moisture exists in the insulating oil, the solvent (upper layer) turns blue. Then, a method in which the Karl Fischer reagent is added by a syringe and the point where the color becomes yellow brown by visual judgment is used as the end point. In addition to such a conventional method, as a method for easily and accurately measuring the amount of water in oil, an alcohol solvent containing an indicator and dehydrated with a Karl Fischer reagent and an oil to be measured are used. There has been proposed a method of mixing and extracting moisture in the oil into the alcohol solvent, and then measuring the absorbance of the solvent (see, for example, Patent Document 1).

  However, organic solvents used for ALD (Atomic Layer Deposition) materials or CVD (Chemical Vapor Deposition) materials such as silane compounds and phosphites having Si—H in the molecular structure react with the Karl Fischer reagent. For this reason, there are many cases where the Karl Fischer method cannot be used, and a measurement method that does not use the Karl Fischer reagent has been studied. Specifically, as a method for quantitative analysis of the moisture content in the thin film raw material for the vaporization process, there is a method for directly measuring the moisture in the liquid substance by detecting the spectral absorption of water using infrared spectroscopy. is there. A sample having a known moisture content is subjected to spectral absorption measurement by near-infrared spectroscopy to prepare a calibration curve in advance, and using the calibration curve, from the result of spectral absorption measurement of the thin film raw material for vaporization process to be analyzed, Calculate the content. A method of creating a calibration curve, processing data of measurement results, and the like according to a conventional method has been proposed (see, for example, Patent Document 2).

JP 2000-88836 A JP 2007-9254 A

However, the method for measuring moisture in an organic solvent or the measuring apparatus as described above may cause various problems as described below.
(I) In the Karl Fischer titration method, the sealed container must be opened, a certain amount must be collected with a syringe or the like, and introduced offline into the analyzer. For this reason, it is unavoidable that water is mixed from the environment during sampling, and the lower limit of detection of the water concentration that can be actually measured is about 10 ppm, and it is difficult to measure a trace amount of water concentration. In addition, organic solvents with high toxicity and odor are very dangerous because the sample may leak into the measurement environment during sample collection. In order to improve these problems, it is known to perform Karl Fischer titration in a dry inert gas atmosphere glove box, but in order to measure a moisture concentration of 1 ppm, at least the glove box has It is necessary to control the moisture concentration to less than 1 ppm, and it takes considerable cost and work time to manufacture the glove box and to manage the moisture using purge gas. Further, as described in Patent Document 2, it is impossible to measure an organic solvent that reacts with a reagent used for titration by the Karl Fischer method, but a method for measuring moisture in an organic solvent without such restriction is indispensable. is there.

(Ii) In addition, in the production facilities as described above, since organic solvents are used continuously, there is a strong demand for in-line trace moisture measuring devices and measuring methods. At this time, a conventional analyzer as described in Patent Document 2 sets the collected organic solvent in the sample cell of the measuring apparatus, and in a predetermined range of wavelength range (in Example 1 of Patent Document 2, a near infrared spectrum). Absorption is measured in the range of 11000 to 2500 cm ⁻¹ ) and cannot be applied in-line as it is. In addition, in order to be applied for in-line use, in such an analyzer, it is possible to continuously supply samples, and not only ensure basic functions such as ambient temperature and installation conditions, but also the operability and accuracy of the instrument. Therefore, it is necessary to accurately control the pressure, temperature, and flow rate conditions for organic solvents.

  The object of the present invention is to enable continuous measurement of a small amount of water in an organic solvent efficiently and with high measurement accuracy in a production facility or the like in a relatively simple configuration, An object of the present invention is to provide an in-line trace moisture measuring apparatus and measuring method in an organic solvent that is easy to handle with respect to a difficult-to-handle sample.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the following in-line trace moisture measuring apparatus and measuring method in an organic solvent, and to complete the present invention. Arrived.

  The present invention relates to an in-line trace moisture measuring apparatus in an organic solvent, which targets an in-line organic solvent that has been dehydrated in advance, is introduced, and is heated to a predetermined temperature that is equal to or higher than the boiling point of the organic solvent. A fixed amount filling tank having a predetermined capacity, a solvent introducing part for introducing the organic solvent into the fixed filling tank, a solvent delivery part for delivering the heat-treated organic solvent, and the fixed filling tank A solvent transfer unit for transferring the organic solvent to the consumption facility, a transfer channel through which the organic solvent is transferred from the solvent introduction unit to the consumption facility, and the heat-treated organic solvent provided in the transfer channel. A transfer amount control unit that controls to transfer a predetermined amount, and an organic solvent that is provided in the transfer flow path and is transferred from the solvent delivery unit is measured using Fourier transform infrared spectroscopy or cavity ring-down spectroscopy. And that the analysis unit, characterized in that it comprises a.

  In the measurement of moisture concentration in in-line organic solvents, it is a robust and relatively simple configuration suitable for in-line measuring devices, and it has good operability and is capable of measuring trace amounts of water in organic solvents efficiently and continuously. At the same time, it is possible to transfer organic solvents to samples that are difficult to handle, especially trace amounts of water, taking into account the influence of moisture from the outside, outflow from the inside of the channel, or adsorption to the inner wall of the channel. It is necessary to reliably manage the quantitativeness with respect to the amount and to ensure high measurement accuracy with respect to the moisture concentration. In response to the former requirement, the present invention provides a Fourier transform infrared spectrophotometry (hereinafter referred to as “FTIR”) or cavity ringdown in which the optical system has high stability and can easily correct and compensate for disturbance effects as an analysis unit. In addition to using the spectroscopic method (hereinafter referred to as “CRDS”), in response to the latter requirement, the pressure rises due to the vaporization of the organic solvent by heating, especially filling a fixed-capacity fixed-volume tank once, and heating the fixed-volume tank at a constant temperature Ensures the driving force to transfer a certain amount of organic solvent. This configuration makes it possible to accurately measure the quantitativeness of organic solvents (absolute amounts corrected for pressure and temperature) that are introduced into the analyzer and measured, that is, the absolute amount of moisture in the transferred organic components. . This makes it possible to measure trace amounts of water in organic solvents efficiently and continuously with high measurement accuracy with a relatively simple configuration in-line in production equipment, etc. This makes it possible to provide an in-line trace moisture measuring device in an organic solvent that is easy to operate for difficult samples. In addition, since it can be measured in-line, there is no possibility of leakage to the environment during sampling and analysis, and it is possible to deal with highly toxic and odorous organic solvents. In addition, the Karl Fischer method cannot measure moisture in an organic solvent that reacts with a reagent, but this method has no incompatibility depending on the type of organic solvent.

The present invention provides an in-line trace moisture measuring apparatus in the organic solvent, wherein the transfer amount control unit is configured to control the mass flow rate of the organic solvent provided in the transfer flow path or the weight of the fixed filling tank. Means for controlling the transfer weight of the solvent is provided, and the integrated transfer amount of the organic solvent is controlled to a predetermined capacity equivalent to or less than the internal volume of the fixed filling tank.
As described above, one of the features of the present invention is the quantitative transfer of the organic solvent by constant temperature heating at a constant volume filled in the fixed charge tank. As a method for further improving the accuracy of quantitative transfer of organic solvents, a flow meter (for example, an integrated flow meter or a mass flow meter) and a control valve are provided in the transfer amount control unit, or the weight of the quantitative filling tank is measured and filled. It is preferable to control the transfer weight of the organic solvent using a method of calculating the weight change from the above. At this time, a predetermined capacity corresponding to or less than the internal volume of the fixed-filling tank is set as a control index, and the integrated transfer amount of the organic solvent can be appropriately controlled by being controlled based on such an index. Although the specific value will be described later, when a sufficient amount of an organic solvent that evaporates at a predetermined temperature is filled in the fixed amount filling tank to have a predetermined vapor pressure at that temperature, the fixed amount filling tank is heated to that temperature. By transferring the entire amount of the vaporized organic solvent using a vacuum pump, the organic solvent in terms of gas equivalent to the internal volume of the fixed filling tank is transferred. At this time, by continuously measuring the moisture concentration in the organic solvent transferred at a constant flow rate, an instantaneous moisture amount can be obtained, and an integrated value at a constant time interval or the total amount of moisture in the organic solvent can be obtained. Can do.

The present invention is an in-line trace moisture measuring apparatus in the organic solvent, wherein the organic solvent in the quantitative filling tank is controlled so as to be at a predetermined liquid level position, a predetermined temperature condition, and a predetermined pressure condition. It has the part.
In this measuring apparatus, it is important to grasp the total capacity of the organic solvent in a member such as a fixed-quantity filling tank and in the flow channel. The present invention grasps the total volume of the organic solvent introduced into the measuring apparatus based on the state of the organic solvent in the fixed-quantity filling tank provided at the first stage. It became possible to continuously measure a small amount of moisture efficiently and with high measurement accuracy.

The present invention is an in-line trace moisture measuring device in the organic solvent, wherein an inert gas introduction unit is provided in the metering filling tank, and before the organic solvent is introduced, from the metering filling tank to the consuming equipment. Purging that performs an inert gas purge of the transfer flow path and starts supplying an organic solvent to the fixed-quantity filling tank when the moisture concentration in the inert gas introduced into the analysis unit is equal to or lower than a predetermined value set in advance. A control unit is provided, and the transfer amount control unit controls the transfer amount to the consumption facility by pumping the organic solvent in the fixed filling tank.
With such a configuration, it is possible to remove in advance moisture generated by residual or springing, which may be an error factor that greatly affects the measurement accuracy of the moisture concentration in the organic solvent. At the same time, such a purge gas is often used in an in-line such as a normal production facility, and mixing into the in-line is less likely to be an obstacle. Also, in the transfer of organic solvents, the organic solvent itself can be used as a carrier gas to assist the transfer when the transfer capability of the organic solvent itself is small (particularly when the adsorptivity in the gas phase is strong or the viscosity is high). It became possible to continuously measure a very small amount of water in a solvent efficiently and with high measurement accuracy.

In the present invention, the element constituting the in-line trace moisture measuring device in the organic solvent is provided in a bypass channel branched from the main channel of the in-line organic solvent, and the organic solvent discharged from the analysis unit is The main flow path is refluxed or transferred to a separate consumption facility.
As described above, the in-line trace moisture measuring apparatus may be required to strictly manage and control the flow rate, pressure, temperature, and the like of the organic solvent serving as a sample in order to maintain the measurement accuracy. In the present invention, the conditions required for an organic solvent such as a cleaning liquid used in a production apparatus such as a semiconductor or a solar cell are different from the conditions required for an in-line trace moisture measuring apparatus, or are affected by each other. In order to cope with cases where this is not appropriate, a flow path for an in-line trace moisture measuring device is provided to ensure measurement conditions for an appropriate organic solvent (including moisture) and maintain high measurement accuracy. is there.

Further, the present invention is an in-line trace moisture measuring method in an organic solvent, using the in-line trace moisture measuring device in an organic solvent according to any of the above,
A primary process comprising the following processes:
(1) The transfer flow path from the fixed filling tank to the consumption facility is purged with an inert gas in advance.
(2) The purged inert gas is introduced into the analyzer, and the moisture concentration in the inert gas is measured and compared with a predetermined value set in advance.
A secondary processing process comprising the following processes:
(3) When the moisture concentration is equal to or less than the predetermined value, an organic solvent is introduced into the fixed filling tank, and the introduction amount is controlled so as to maintain a predetermined liquid level position set in advance.
(4) The fixed filling tank is heated to a predetermined temperature equal to or higher than the boiling point of the organic solvent, and is controlled so as to satisfy a preset pressure condition.
(5) The organic solvent is delivered from the fixed filling tank in a heated state. The amount of the organic solvent delivered is controlled until the pressure in the fixed filling tank reaches a predetermined pressure set in advance or the weight reduction amount of the fixed filling tank reaches a predetermined weight set in advance.
A tertiary process consisting of the following processes:
(6) The delivered organic solvent is introduced into the analysis unit, and the water concentration in the organic solvent is measured.
A quaternary processing process comprising the following processes;
(7) When the instantaneous moisture concentration in the organic solvent, the average value of the moisture concentration, or the integrated value of the moisture concentration is equal to or less than a predetermined value set in advance, the organic solvent is supplied to the consuming equipment.
It is characterized by having.
By using the in-line trace moisture measuring apparatus having the above-mentioned configuration and processing by such a process, a trace amount of moisture in an organic solvent can be efficiently and highly measured in a relatively simple configuration in the production line. At the same time, it has become possible to provide an in-line trace moisture measurement method in an organic solvent that is easy to handle, particularly for difficult samples that are difficult to handle, in addition to being able to measure continuously with accuracy.

Schematic showing a basic configuration example of an in-line trace moisture measuring apparatus in an organic solvent according to the present invention Schematic which shows the structural example of the fixed-quantity filling tank with which the moisture measuring device which concerns on this invention was equipped. Schematic which shows the other structural example of the fixed-quantity filling tank with which the moisture measuring device which concerns on this invention was equipped. Schematic which shows the other structural example of the in-line trace moisture measuring apparatus in the organic solvent which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is an in-line trace moisture measuring device (hereinafter referred to as “the present device”) in an organic solvent, in which an in-line organic solvent that has been dehydrated in advance is introduced, and is heated to a predetermined temperature above the boiling point of the organic solvent. A fixed-capacity filling tank having a predetermined capacity, a solvent introduction part for introducing an organic solvent into the fixed-filling tank, a solvent delivery part for delivering a heat-treated organic solvent, and an organic solvent for the quantitative filling tank. A solvent transfer unit for transferring to the consumption facility, a transfer channel for transferring the organic solvent from the solvent delivery unit to the consumption facility, and a control for transferring a predetermined amount of the heat-treated organic solvent provided in the transfer channel. A transfer amount control unit, and an analysis unit that is provided in the transfer channel and that measures the organic solvent transferred from the solvent delivery unit using Fourier transform infrared spectroscopy or cavity ring-down spectroscopy. Features and That.

  The “organic solvent” here is not particularly limited, including various process gases, and includes solvents that are widely used industrially, for example, organic solvents such as octane, chlorofluorocarbon organic solvents and the like. In general, it is liquid at normal temperature (20 to 30 ° C.) and normal pressure (about 0.1 MPa), but here also includes a solvent that is liquefied widely under pressure or low temperature. Specifically, organic solvents after being used as cleaning liquids for manufacturing equipment such as semiconductors and solar cells, or organic solvents used in these research facilities and organic solvents used as raw materials for organic synthesis reactions, etc. Can be mentioned. Saturated hydrocarbons (such as n-hexane and n-octane), cyclic saturated hydrocarbons (such as cyclohexane), ketones (such as acetone), esters (such as ethyl acetate), and aromatic compounds (such as benzene and toluene) ), Cyclic ether compounds (such as THF), and heterocyclic compounds (such as pyridine). This device can also be applied to the case where an organic solvent containing low-concentration water, which has been difficult in the past, is used as a measurement target, as in verification with n-hexane or n-octane described later, This is useful when measuring an organic solvent with a very small residual water content (about 10 ppm or less).

<Basic configuration example of this device>
FIG. 1 is a schematic diagram showing a basic configuration example (first configuration example) of the apparatus A, in which a fixed filling tank 10 into which an organic solvent to be treated is introduced and stored, and an organic vaporized in the fixed filling tank 10. An analysis unit 20 for measuring a trace amount of water in the solvent is provided. Connected to the fixed-quantity filling tank 10 are a solvent introduction part 1 into which an organic solvent is introduced and a solvent delivery part 2 through which a heat-treated and vaporized organic solvent (hereinafter referred to as “treatment gas”) is delivered. The processing gas delivered from the solvent delivery unit 2 is introduced into the analysis unit 20 via the transfer channel L and then supplied to the consumption facility 30. The transfer of the processing gas is operated by the vapor pressure accompanying the vaporization of the organic solvent in the fixed filling tank 10 and the suction pressure of the vacuum pump 3 provided downstream of the analysis unit 20, and the solvent transfer unit is the vacuum pump 3 and its pressure. The buffer tank BF has a buffer function. The solvent introduction unit 1 is provided with an integrating flow meter F1 and a control valve V1 for controlling the introduced organic solvent, and the solvent delivery unit 2 is provided with a mass flow meter F2 and a control valve V2 for controlling the treated process gas. And a pressure regulating valve R1 for controlling the pressure of the fixed-quantity filling tank 10 and the analyzer 20 is provided downstream of the analyzer 20, and these constitute a transfer amount controller. In addition to these, in the transfer flow path L, on-off valves S1 to S9 for controlling introduction and supply or bypass of gas and liquid organic solvent to and from the quantitative filling tank 10, analysis unit 20 and consumption equipment 30, and these Pressure gauges P1 to P3 for managing pressure are provided. Further, here, a container 4 is provided as a supply source of the organic solvent, and the organic solvent is supplied to the fixed-quantity filling tank 10 through the solvent introduction part 1, and the inert gas is supplied from the pressure regulating valve R2 and the pressure gauge P4. The structure introduce | transduced into the container 4 via the inert gas introducing | transducing part 5 provided with is shown. Needless to say, the arrangement and necessity of installation of these components are not limited to the configuration shown in FIG. For example, a back pressure adjusting means is used as the pressure adjusting valve R1 and is provided between the analyzer 20 and the vacuum pump 3 together with the pressure gauge P2. However, the present invention is not limited to this. Various configurations such as a configuration for adjusting pressure by providing a vacuum suction pump and secondary pressure adjusting means (not shown) can be used.

  The target organic solvent is introduced from the solvent introduction unit 1 into the fixed-quantity filling tank 10 from the container 4 through the on-off valve S12, the integrating flow meter F1, the control valve V1, and the on-off valve S1, until the liquid level reaches a predetermined level. The control valve V1 is actuated by a control unit (not shown) to replenish new organic solvent. When transferring from the inside of the container 4, an inert gas is introduced from the inert gas introduction part 5, and a desired transfer amount can be provided by pressing the organic solvent liquid surface in the container 4. Such a purge gas is often used also in an in-line such as a production facility, and mixing into the in-line is less likely to be an obstacle. The organic solvent introduced into the fixed-quantity filling tank 10 is heated and vaporized in a state where the liquid level is substantially constant, and is then supplied from the solvent supply unit 2 via the control valve V2. The vaporized organic solvent is introduced into the analysis unit 20 through the mass flow meter F2 and the on-off valve S4 as a processing gas together with moisture. The processing gas whose trace amount of water in the organic solvent has been measured by the analysis unit 20 is buffered by the buffer tank BF via the on-off valve S6, the pressure regulating valve R1, and the on-off valve S7, and then the vacuum pump through the on-off valve S9. 3 and sucked by the consumption equipment 30. The organic solvent filled in the fixed-quantity filling tank 10 can be efficiently measured by the analysis unit 20 in a vaporized state. At this time, the flow path in which the processing gas is transferred in the transfer flow path L or the constituent elements (specifically, the broken line portion in FIG. 1) is configured to be heatable. Is preferred. Liquefaction of the vaporized organic solvent or adsorption of moisture to the inner wall of the flow path can be prevented, and a high purge effect can be ensured particularly during purge treatment with an inert gas. In addition, since it can be measured in-line, there is no possibility of leakage to the environment during sampling and analysis, and it is possible to deal with highly toxic and odorous organic solvents. In addition, the Karl Fischer method cannot measure moisture in an organic solvent that reacts with a reagent, but this method has no incompatibility depending on the type of organic solvent.

  Further, the water dissolved or mixed in the organic solvent filled in the quantitative filling tank 10 is accompanied by the vaporized organic solvent and introduced into the analysis unit 20 as a part of the processing gas, and the concentration of the component is measured. The At this time, when the water concentration exceeds a predetermined value (for example, 10 ppm), the vacuum pump 3 is stopped and the on-off valve S9 is closed, thereby supplying the organic solvent having a high water concentration to the consumption facility 30. Can be stopped. Further, when the organic solvent in the container 4 is continuously supplied to the consumption facility 30, after it is confirmed that the moisture concentration in the organic solvent is low in the quantitative measurement at the initial stage, the quantitative filling tank 10 and the analysis unit 20 are used. In addition, the buffer tank BF can be passed and continuously supplied to the consumption facility 30. Specifically, with respect to the fixed-quantity filling tank 10, the on-off valves S1, S3 are closed / the on-off valve S2 is opened, the analysis unit 20 is opened with the on-off valves S4, S6 are closed / the on-off valve S5 is opened, and the buffer tank BF. By opening / closing the on-off valves S7 and S9 and opening the on-off valve S8, the shortest and simple transfer flow path L can be formed, and the organic matter with good operability is low in the risk of moisture mixing and springing out. The solvent can be supplied.

  Further, as the inert gas for purging the transfer channel L, for example, a gas that has few impurities such as moisture and is easily available, such as nitrogen and argon, is preferable. The inert gas is controlled by the pressure regulating valve R2 so as to have a predetermined supply flow rate set in advance, and is introduced into the metered filling tank 10 through the container 4 or directly from the solvent introduction unit 1. The introduced inert gas is sequentially fed to the consumption facility 30 via the vacuum pump 3 through the same flow path as the transfer of the organic solvent such as the analysis unit 20, thereby purging the entire transfer flow path L. can do. At this time, by heating the transfer channel L, impurities adsorbed on the inner wall of the channel can be effectively purged.

[Composition of the fixed filling tank]
As illustrated in FIG. 2, the fixed-fill tank 10 has a heating means 10a for controlling the organic solvent to a predetermined temperature condition and a liquid level height so as to be substantially constant at a predetermined liquid level position set in advance. A liquid level gauge 10b for detecting the height is provided. The heating means 10a is provided with a temperature sensor or a control unit (not shown), and a jacket heater, a sheathed heater, and the like are disposed inside or on the outer periphery of the fixed-quantity filling tank 10. As the liquid level gauge 10b, for example, an ultrasonic sensor or a float sensor is used, and the liquid level gauge 10b is disposed in the inside or the outer peripheral portion of the fixed amount filling tank 10.

  The control temperature of the fixed filling tank 10 is preferably a temperature that can ensure the transpiration of moisture and the vaporization of the organic solvent. Specifically, when n-hexane vaporized at 69 ° C. or less is charged into a fixed-volume tank having an internal volume of 100 L and a sufficient amount to have a vapor pressure of 0.1 MPa at 69 ° C., the fixed-volume tank is By transferring the whole amount of n-hexane heated to 69 ° C. and vaporized using a vacuum pump, 100 L of n-hexane in terms of gas is transferred. About some organic solvents, the following boiling points can be illustrated as shown in [Table 1]. The specific heating temperature is preferably higher than the temperature of [Table 1], and preferably 10 to 30 ° C higher.

  Here, as illustrated in FIG. 3, the inert gas introduction unit 6 is provided in the metering filling tank 10, and the organic solvent is transferred from the metering filling tank 10 to the consumption facility 30 before being introduced into the metering filling tank 10. It is preferable to purge the flow path L with an inert gas. At the same time, it is preferable that the moisture concentration in the inert gas at this time is measured by the analysis unit 20, and the supply of the organic solvent to the quantitative filling tank 10 is started when it is equal to or less than a predetermined value set in advance. Such a control function is performed by a purge control unit (not shown), and moisture generated by residual or springing in the measurement system may cause an error factor that greatly affects the measurement accuracy of the moisture concentration in the organic solvent. Can be removed in advance. Further, such an inert gas has a function of controlling the transfer amount to the consuming equipment 30 by pressure-feeding the organic solvent remaining in the fixed filling tank simultaneously with the purge function. In particular, when the transfer capability of the organic solvent itself is small (for example, when the adsorptivity in the gas phase is strong or the viscosity is high), the on-off valve S13 is opened and the inert gas is ensured to be quantitative by the mass flow meter F3. However, by using it as a carrier gas, it became possible to continuously measure a very small amount of water in an organic solvent efficiently and with high measurement accuracy. Moreover, it is preferable that a transfer flow path makes the upper limit the temperature higher than the temperature of said [Table 1], and 10-30 degreeC high.

[Structure of analysis section]
The analysis unit 20 controls and manages the water concentration in the organic solvent to be supplied, and ensures an appropriate quality for the consumption equipment 30. Specifically, the analysis unit 20 performs Fourier transform infrared spectrophotometry ( A detector (not shown) using FTIR) or cavity ring-down spectroscopy (CRDS) is arranged with a controller (not shown). Here, the FTIR uses a Michelson interferometer as an optical system, detects light interference and light intensity caused by an optical path difference caused by the movement of a moving mirror that constitutes the optical system, Quantification can be performed. Specifically, an interference pattern (interferogram) with time or frequency formed from the detection output as an index can be converted into a spectrum with each frequency component as the horizontal axis by performing a fast Fourier transform. Versatile because it can be measured. In particular, the degree of freedom with respect to the arrangement of a sample cell (not shown) for introducing a measurement object into the optical system is high, and a configuration using a long optical path cell for low concentration measurement or a sample cell as in this apparatus is predetermined. The configuration of heating with temperature is easy, and it is suitable as an in-line measuring device. In addition, CRDS irradiates an optical cavity provided with reflecting mirrors at both ends, detects a change in the amount of attenuated light from the cavity into which a measurement target (sample) is introduced, and absorbs an absorption amount of a specific wavelength. Qualitative and quantitative measurement can be performed from changes. Since the effective optical path length is increased by increasing the number of reflections, it is suitable for low-concentration measuring devices such as this device and measures the light decay time, making it less susceptible to fluctuations in laser intensity. High measurement accuracy can be ensured. In addition, it is suitable as an in-line measuring device because it is easy to operate. In addition, all have excellent functions such as high stability of the optical system, easy correction and compensation of disturbance effects, robust and relatively simple configuration suitable for in-line measuring devices, and good operability. It is possible to efficiently and continuously measure a small amount of water in an organic solvent.

  The analysis unit 20 is provided with a heating means 20a for maintaining the processing gas at a predetermined temperature (a temperature equal to or higher than the boiling point of the organic solvent) so as not to condense the processing gas. The heating means 20a includes a temperature sensor or a control unit (not shown), and a heater, a heating steam pipe, and the like are disposed inside or on the outer periphery of the analysis unit 20. The heating temperature is preferably a temperature that suppresses the temperature effect on the analysis unit 20 while preventing condensation of the organic solvent. Specifically, it is preferable that the upper limit is a temperature higher than the temperature of [Table 1] and higher by 10 to 30 ° C.

[Other configuration examples of this device]
In the present apparatus, as illustrated in FIG. 4, the present apparatus A is provided in a bypass flow path Lb branched from an in-line organic solvent main flow path M, and the organic solvent discharged from the analysis unit 20 is The main flow path M can be refluxed or transferred to a separate consumption facility 31. When conditions required for organic solvents such as cleaning liquids used in production equipment such as semiconductors and solar cells are different from those required for in-line trace moisture measuring devices, it is not appropriate to receive mutual influences Corresponding to the case, by arranging the bypass flow path Lb for the apparatus A, regardless of the state of the main flow path M (regardless of whether the organic solvent is supplied to the consumption equipment 30), It ensures the appropriate measurement conditions for organic solvents (including moisture) and maintains high measurement accuracy.

  In the normal operation of the main flow path M, the organic solvent delivered from the container 4 is supplied to the consumption facility 30 via the integrating flow meter F4, the control valve V3, the mass flow meter F7, and the vacuum pump 7. Here, when an abnormality occurs in the moisture concentration in the supplied organic solvent and the measurement value of the analysis unit 20 that measures a part of the organic solvent introduced into the bypass flow path Lb exceeds a predetermined value, In the operation of the main flow path M, the vacuum pump 7 is immediately stopped and the control valve V3 is closed, so that adverse effects on the consumption equipment 30 can be avoided.

<Method for treating organic solvent in this apparatus>
In this apparatus having the above-described configuration, moisture in the organic solvent is measured along the following primary to quaternary treatment processes. A case where each process is controlled by a control unit (not shown) based on the configuration shown in FIG. 1 will be described as an example. Here, [1] the primary treatment process is a preliminary treatment operation, [2] the secondary treatment process is performed in the fixed-quantity filling tank 10, and [3] the tertiary treatment process and [4]. In the quaternary processing process, a processing operation is performed in the analysis unit 20.

[1] Primary processing process The primary processing process includes the following processes.
(1) The transfer flow path L from the fixed filling tank 10 to the consumption equipment 30 is purged with an inert gas in advance. Specifically, the on-off valves S10, 12 are closed / the on-off valve S11 is opened, and the inert gas whose supply pressure is controlled by the pressure adjusting valve R2 using the output of the pressure gauge P4 as an index is the inert gas introduction unit 5. To the present apparatus A. In the apparatus A, the open / close valves S1 and S3 are opened / closed in the fixed filling tank 10, the open / close valves S2 are closed, and the open / close valves S4 and S6 are closed in the analysis unit 20 and the buffer tank BF is closed. With respect to the above, by opening the on-off valves S7 and S9 and closing the on-off valve S8, the inside of the flow paths of these constituent elements and the respective constituent elements such as the integrated flow meter F1 and the mass flow meter F2 are purged and cleaned. can do.
(2) The purged inert gas is introduced into the analyzer 20, and the moisture concentration in the inert gas is measured and compared with a predetermined value set in advance. If it is higher than the predetermined value, the purge is continued, and the purge is completed when the state below the predetermined value continues for a predetermined time.

[2] Secondary processing process The secondary processing process includes the following processes.
(3) When the water concentration measured by the analysis unit 20 is equal to or lower than a predetermined value, the amount of the introduced organic solvent is introduced into the fixed-quantity filling tank 10 so as to maintain a predetermined liquid level position set in advance. Be controlled. Specifically, after the purge is completed, the on-off valves S10 and 11 are closed, and the inert gas inside the transfer flow path L and each component is removed. Completion of removal can be determined using the degree of pressure reduction of the pressure gauge P1 as an index, and then the on-off valves S10 and 12 are opened / closed and the on-off valve S11 is closed, and the output of the pressure gauge P4 is used as an index. The inert gas whose pressure is controlled is introduced into the container 4 from the inert gas introduction part 5. The organic solvent in the container 4 is introduced into the apparatus A through the on-off valve S12 when the liquid level is pressed, and the organic solvent is supplied to the fixed-quantity filling tank 10 through the solvent introduction unit 1. When the liquid level detected by the liquid level gauge 10b reaches a predetermined height, the control valve V1 is closed, and a liquid phase part and a gas phase part are formed. For the filling amount, the pressure condition set in advance by the inner volume of the fixed-quantity filling tank 10 at the set heating temperature is used as an index. For example, as described above, n-hexane vaporized at 69 ° C. or lower is used as the inner volume. An amount sufficient to have a vapor pressure of 0.1 MPa at 69 ° C. in the 100 L fixed filling tank is the filling amount.
(4) The fixed filling tank 10 is heated to a predetermined temperature equal to or higher than the boiling point of the organic solvent, and is controlled so as to satisfy a preset pressure condition. Specifically, the heating means 10a controls the temperature corresponding to the type of the organic solvent to be introduced, its water concentration, and the water concentration in the organic solvent of the product. It is preferable that the upper limit is a temperature higher than the temperature of [Table 1] and higher by 10 to 30 ° C. At this time, by opening the on-off valve S3 and closing the control valve V2, the internal pressure of the fixed filling tank 10 can be set to a predetermined value, and the internal pressure can be monitored by the pressure gauge P1.
(5) The organic solvent is delivered from the fixed filling tank 10 in a heated state. Specifically, when the internal pressure of the fixed-fill tank 10 reaches a predetermined value, the control valve V2 controls the flow rate to a predetermined flow rate, and starts to transfer the processing gas to the analysis unit 20. The process gas transfer driving force is formed according to the temperature and pressure conditions in the fixed filling tank 10. The transfer flow rate is monitored by the mass flow meter F2, and in the case of a mass flow meter having a control function, a minute amount adjustment is performed thereby. The amount of the organic solvent to be delivered is controlled until the pressure of the fixed filling tank 10 reaches a predetermined pressure set in advance or the weight reduction amount of the fixed charge tank reaches a predetermined weight set in advance. As a result, a fixed amount of the organic solvent in the gas phase is supplied as the processing gas. At this time, an in-line monitoring function can be ensured by replenishing the decrease amount of the organic solvent accompanying the supply continuously or batchwise. Moreover, it is preferable that the flow path from the fixed-quantity filling tank 10 to the analysis part 20 is controlled to the temperature which makes the upper limit the temperature higher than the temperature of said [Table 1] and 10-30 degreeC higher.

[3] Tertiary processing process The tertiary processing process includes the following processes.
(6) The delivered organic solvent (processing gas) is introduced into the analysis unit 20, and the water concentration in the organic solvent is measured. Specifically, the processing gas controlled to a predetermined flow rate by the control valve V2 is introduced into the analysis unit 20 by opening the on-off valves S4 and S6. At this time, the pressure of the sample cell (not shown) in the analysis unit 20 is controlled by the pressure regulating valve R1, and the temperature is higher than the temperature of the above [Table 1], and is 10 to 30 ° C higher. It is preferable that the temperature is controlled as follows. By maintaining certain measurement conditions, the water concentration in the organic solvent can be measured with high measurement accuracy.

[4] Quaternary process The quaternary process consists of the following processes.
(7) When the instantaneous moisture concentration in the organic solvent, the average value of the moisture concentration, or the integrated value of the moisture concentration is equal to or less than a predetermined value set in advance, the organic solvent is supplied to the consumption facility 30. Specifically, when the processing gas is continuously transferred from the fixed filling tank 10, the instantaneous water concentration is continuously compared with a predetermined value, and when the processing gas is transferred batchwise, the water concentration When the average value or the integrated value of the moisture concentration is compared with a predetermined value corresponding to the average value or the integrated value, and the specification required by the consuming equipment 30 is met, the opening / closing valve S8 is opened / closed. When the vacuum pump 3 is closed, the organic solvent controlled to have a desired moisture concentration can be supplied from the apparatus A to the consumption facility 30.

[Verification of measurement accuracy with this device]
As verification of the measurement accuracy in this apparatus, the organic solvent transfer processing function in the fixed-fill tank 10 and the measurement accuracy in the analysis unit 20 were verified as follows.

(A) Transfer conditions of organic solvent in quantitative filling tank Measurement conditions in analysis section Using this apparatus shown in FIG. 1, under the conditions shown in [Table 2] below, organic solvent before and after dehydration treatment (containing about 40 ppm water) n-hexane, n-octane containing about 50 ppm water) was introduced into the fixed-fill tank 10, and the moisture concentration in the organic solvent was measured in the analysis unit 20.

(B-2) Experimental result The following [Table 3] shows the verification result in n-hexane, and the following [Table 4] shows the verification result in n-octane. Compared with the Karl Fischer titration method, which is a conventional technique for measuring the water concentration in an organic solvent, the lower limit of detection could be remarkably improved. In addition, the Karl Fischer method cannot measure moisture in an organic solvent that reacts with a reagent, but this method has no incompatibility depending on the type of organic solvent.

DESCRIPTION OF SYMBOLS 1 Solvent introduction part 2 Solvent delivery part 3,7 Vacuum pump 4 Container 5 Inert gas introduction part 10 Fixed filling tank 10a, 20a Heating means 10b Level gauge 20 Analysis part 30,31 Consumption equipment BF Buffer tank F1, F4 Integrated flow rate Total F2, F3, F5 Mass flow meter L Transfer flow path Lb Bypass flow path M Main flow path P1-P4 Pressure gauge R1 Pressure regulating valve S1-S13 On-off valve V1-V3 Control valve

Claims (6)

  A fixed-quantity filling tank, which is intended for an in-line organic solvent that has been dehydrated in advance, has a predetermined capacity that can be heated to a predetermined temperature that is equal to or higher than the boiling point of the organic solvent, and the fixed-quantity filling tank A solvent introduction part into which the organic solvent is introduced, a solvent delivery part from which the heat-treated organic solvent is delivered, a solvent transfer part for transferring the organic solvent in the metering tank to a consumption facility, and an organic solvent A transfer channel that is transferred from the solvent introduction unit to the consumption facility, a transfer amount control unit that is provided in the transfer channel and controls to transfer a predetermined amount of the heat-treated organic solvent, and the transfer flow And an analysis unit that measures the organic solvent transferred from the solvent delivery unit using Fourier transform infrared spectroscopy or cavity ring-down spectroscopy. Trace moisture measurement device.   The transfer amount control unit has means for controlling the mass flow rate of the organic solvent provided in the transfer channel or means for controlling the transfer weight of the organic solvent from the weight of the fixed filling tank, and the integrated transfer amount of the organic solvent The in-line trace moisture measuring device in an organic solvent according to claim 1, wherein the volume is controlled to a predetermined capacity equivalent to or less than the internal volume of the fixed-fill tank.   3. The organic solvent according to claim 1, further comprising a control unit configured to control the organic solvent in the fixed-quantity filling tank to have a predetermined liquid level position, a predetermined temperature condition, and a predetermined pressure condition. In-line trace moisture measuring device.   An inert gas introduction part is provided in the fixed-quantity filling tank, and before the organic solvent is introduced, an inert gas purge of the transfer channel from the fixed-quantity filling tank to the consumption equipment is performed, and the introduced into the analysis part When the moisture concentration in the inert gas is equal to or lower than a predetermined value set in advance, a purge control unit is provided for starting the supply of the organic solvent to the quantitative filling tank. The in-line trace moisture measuring device in an organic solvent according to any one of claims 1 to 3, wherein the solvent is pumped to control a transfer amount to the consumption facility.   5. The organic solvent discharged from the analysis unit while the elements constituting the in-line trace moisture measuring device according to claim 1 are provided in a bypass channel branched from an in-line organic solvent main channel However, the in-line trace moisture measuring device in the organic solvent is refluxed to the main channel or transferred to a separate consumption facility. Using the in-line trace moisture measuring device in the organic solvent according to any one of claims 1 to 5,
A primary process comprising the following processes:
(1) The transfer flow path from the fixed filling tank to the consumption facility is purged with an inert gas in advance.
(2) The purged inert gas is introduced into the analyzer, and the moisture concentration in the inert gas is measured and compared with a predetermined value set in advance.
A secondary processing process comprising the following processes:
(3) When the moisture concentration is equal to or less than the predetermined value, an organic solvent is introduced into the fixed filling tank, and the introduction amount is controlled so as to maintain a predetermined liquid level position set in advance.
(4) The fixed filling tank is heated to a predetermined temperature equal to or higher than the boiling point of the organic solvent, and is controlled so as to satisfy a preset pressure condition.
(5) The organic solvent is delivered from the fixed filling tank in a heated state. The amount of the organic solvent delivered is controlled until the pressure in the fixed filling tank reaches a predetermined pressure set in advance or the weight reduction amount of the fixed filling tank reaches a predetermined weight set in advance.
A tertiary process consisting of the following processes:
(6) The delivered organic solvent is introduced into the analysis unit, and the water concentration in the organic solvent is measured.
A quaternary processing process comprising the following processes;
(7) When the instantaneous moisture concentration in the organic solvent, the average value of the moisture concentration, or the integrated value of the moisture concentration is equal to or less than a predetermined value set in advance, the organic solvent is supplied to the consuming equipment.
A method for measuring in-line trace moisture in an organic solvent, comprising:

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