JP2011064527A - Gas analyzer and method by continuous concentration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To concentrate and measure sample gas by a concentrator having a simple and easily-operable/handleable structure. <P>SOLUTION: In the concentrator 1 for concentrating sample gas SG including a separation filter 12 formed by bundling many nonporous membrane hollow fibers, the sample gas SG is allowed to pass the separation filter 12 to obtain concentrated sample gas SG1. Further, the separation filter 12 is stored in a storage tube 11, and arranged so that the longitudinal direction of the separation filter 12 is the same as the longitudinal direction of the storage tube 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gas analyzer and method for concentrating and analyzing a low-concentration gas by using a separation filter, and in particular, a gas analyzer and method capable of continuously concentrating and analyzing with a concentrator. About.

  An example of the gas analyzer is a gas chromatograph device. A measuring apparatus using a gas chromatograph is disclosed in Patent Document 1, for example. In this gas chromatographic measurement, when the detection target gas concentration in the sample gas is low and cannot be detected, the sample gas is concentrated to increase the detection target gas concentration in order to improve the detection sensitivity. . An instrument for concentrating a low-concentration sample gas is disclosed in Patent Document 2, for example.

  According to a conventional concentrator, the sample gas passes through a trap tube filled with an adsorbent before being introduced into the detector. The trap tube is cooled to a very low temperature by liquid nitrogen, and the sample gas is condensed in the trap tube. Thereafter, the trap tube is taken out from the liquid nitrogen, and the heater sheathed on the trap tube is heated to separate the sample gas from the adsorbent. Thereby, the sample gas is concentrated and introduced into the separation column together with the carrier gas introduced into the trap tube.

  However, the above-described concentrator uses liquid nitrogen, a trap tube, a heater, and the like, and thus has a very complicated and large-scale configuration and is complicated to operate. In addition, a refrigerant such as liquid nitrogen is difficult to store in a dewar and volatilizes, so it must be replenished at any time and is very complicated. Further, the above method is suitable for intermittent measurement, and the concentrated sample gas cannot be continuously introduced into the analyzer.

JP-A-5-99910 JP-A-7-31801

  Therefore, the problem to be solved by the present invention is to provide a gas analyzer and method capable of continuously concentrating and measuring a sample gas with a concentrator having a simple structure that is easy to operate and handle. It is.

In order to solve the above problems, a gas analyzer according to the present invention provides:
In a gas analyzer that performs measurement by concentrating sample gas with a concentrator, the concentrator includes a separation filter in which a large number of non-porous membrane hollow fibers are bundled, and the sample gas is passed through the separation filter to concentrate the sample gas. And

  Preferably, the separation filter is housed in a housing tube, the longitudinal direction of the separation filter is arranged in the longitudinal direction of the housing tube, and the housing tube has a supply flow for supplying sample gas to one end in the longitudinal direction. A first discharge flow path for discharging the sample gas to the other end in the longitudinal direction thereof, and a second discharge flow path for discharging the sample gas to the outer peripheral surface thereof, the first discharge flow path or the second discharge flow Measure the concentrated sample gas discharged from the channel.

  Preferably, the concentrated sample gas is continuously introduced into the analyzer and continuously measured.

In addition, in order to solve the above problems, a gas analysis method according to the present invention includes:
In a gas analysis method for measuring by concentrating sample gas with a concentrator, a concentrator equipped with a separation filter in which a large number of non-porous membrane hollow fibers are bundled is prepared, and the sample gas is passed through the separation filter to concentrate the sample gas. And

  Preferably, the separation filter is housed in the housing tube, the longitudinal direction of the separation filter is arranged in the longitudinal direction of the housing tube, and the housing tube includes a supply flow path for supplying sample gas to one end in the longitudinal direction. A first discharge channel for discharging the sample gas to the other end in the longitudinal direction, and a second discharge channel for discharging the sample gas on the outer peripheral surface thereof, from the first discharge channel or the second discharge channel. Measure the exhausted concentrated sample gas.

  Preferably, the concentrated sample gas is continuously introduced into the analyzer for continuous measurement.

  As described above, the gas analyzer and method according to the present invention uses a concentrator equipped with a separation filter in which a large number of non-porous membrane hollow fibers are bundled. Since the separation filter is composed of a non-porous membrane hollow fiber, each gas in the sample gas is selectively permeated and imperviously separated by passing the sample gas through the separation filter.

  For example, when detecting argon, nitrogen, etc. (detection target gas) in a sample gas containing hydrogen as a main component, only a predetermined amount of hydrogen permeates through the separation filter and is discharged to the inside. The concentration of argon, nitrogen, etc. (detection target gas) in hydrogen can be increased.

  Conversely, when detecting hydrogen (detection target gas) in a sample gas containing argon, nitrogen, or the like as a main component, by passing only hydrogen to the outside through the separation filter, the outer hydrogen (detection target gas) The concentration can be increased.

  That is, a relatively small amount of a high molecular weight component (for example, argon, nitrogen) in a low molecular weight (for example, hydrogen) is measured, or a small amount of a low molecular weight in a high molecular weight (for example, argon, nitrogen) is measured. Since the component (for example, hydrogen) can be concentrated and measured, the base gas can be concentrated and measured for both low and high molecules.

  As described above, since the sample gas can be concentrated using the separation filter having a simple structure, the operation and handling are very simple. Furthermore, since the sample gas can be concentrated by passing it through a concentrator, it can be continuously introduced into the analyzer for continuous measurement.

It is a block diagram which shows 1st Embodiment of a gas chromatograph apparatus. It is sectional drawing which shows a concentrator. It is a perspective view which shows a non-porous membrane hollow fiber. It is a block diagram which shows 2nd Embodiment of a gas chromatograph apparatus. It is a figure which shows the chromatogram obtained by the gas chromatograph apparatus.

  The gas analyzer and method according to the present invention will be described below with reference to the drawings. In the following, the gas analyzer and method will be described by applying the gas chromatograph device and method. However, the present invention can also be applied to other gas measurement analyzers such as a gas chromatograph-mass spectrometer, NOx meter, and SOx meter. .

[First Embodiment]
First, a first embodiment of a gas chromatograph apparatus will be described.
As shown in FIG. 1, the gas chromatograph apparatus includes a concentrator 1 for concentrating the sample gas SG. The sample gas SG is a sample gas mainly containing hydrogen, for example. The sample gas SG is supplied to the concentrator 1 through the supply channel 5a. The supply flow path 5a includes a flow controller FC and a stop valve ST1 for measuring and sending a sample gas SG having a constant flow rate at a constant speed.

  As shown in FIG. 2, the concentrator 1 includes a cylindrical storage tube 11, and a separation filter 12 is stored in the storage tube 11. The separation filter 12 is configured by bundling a large number of non-porous membrane hollow fibers 10 (FIG. 3) in parallel, and is arranged so that the longitudinal direction thereof faces the longitudinal direction of the storage tube 11.

  As shown in FIG. 3, the non-porous membrane hollow fiber 10 is composed of a cylindrical membrane 10b provided with pores 10a. The membrane 10b is made of polyimide or the like, and selectively transmits the main component (for example, hydrogen) of the sample gas SG as the permeating gas SG2 by molecular gaps generated by thermal vibration.

  As shown in FIG. 2, the storage tube 11 has one end 1a connected to the supply flow path 5a and the other end 1b connected to the first discharge flow path 5b. As a result, the sample gas SG supplied to the storage tube 11 through the supply channel 5 a is discharged through the holes 10 a of the multiple hollow fibers 10 in the separation filter 12. The storage tube 11 has an outer peripheral surface 1 c connected to the second discharge channel 7.

  The second discharge channel 7 is sucked by the suction pump 4. Therefore, when the sample gas SG supplied to the storage tube 11 passes through the hollow fiber 10, a predetermined amount of permeated gas SG <b> 2 that permeates the membrane 10 b is discharged from the second discharge flow path 7. Thereby, since the sample gas SG is discharged as a permeated gas SG2 by a predetermined amount of the main component (for example, hydrogen), the concentrated concentrated sample gas containing a large amount of detection target gas (for example, argon) that does not pass through the membrane 10b. (Analysis gas) SG1 is discharged from the first discharge flow path 5b.

  As shown in FIG. 1, the second discharge channel 7 includes a suction pump 4 that sucks the permeate gas SG2 at a constant speed, and a needle valve NV2 that varies the suction speed according to the concentration rate. The first discharge channel 5b includes a needle valve NV1 that adjusts the concentration amount of the concentrated sample gas SG1, and an atmospheric balance valve ST2 that maintains atmospheric equilibrium.

  Further, as shown in FIG. 1, before the measurement, the stop valve ST3 is controlled, and the purge gas PG is caused to flow through the flow path 6 connected to the concentrator 1 so as to remove the previous gas in which unnecessary air components remain. Purge for.

  For example, when the concentrated sample gas is 100 ml / min with respect to 10.0 L / min of the main component gas, the main component gas (permeate gas SG2) is discharged from the second discharge channel 7 at 9.9 L / min. The concentrated sample gas (analysis gas SG1) is discharged from the first discharge channel 5b at 100 ml / min. Here, since the detection target gas remains in the concentrated sample gas without passing through, it is concentrated at a concentration rate of about 100 times. The concentration rate can be determined by trial to a concentration that can be measured with the highest accuracy according to the components of the sample gas SG, the performance of the detector 3, and the like.

  The gas chromatograph apparatus includes a sampling valve SV and a measuring tube SL. At the time of non-measurement, the flow path of the sampling valve SV is in a solid line state. The concentrated sample gas SG1 is introduced from the first discharge channel 5b, and is discarded from the channel 5e through the flow meter FM via the measuring tube SL. The carrier gas CG is sent to the separation column 2 from the sampling valve SV through the flow path 5d through the control valve PR and the pressure gauge PM through the flow path 5c.

  At the time of measurement (when the sample gas is introduced), the flow path of the sampling valve SV is in a broken line state. The carrier gas CG flows to the separation column 2 through the sampling valve SV and the measuring pipe SL. A certain amount of concentrated sample gas SG1 collected by the measuring tube SL is sent to the separation column 2 by the carrier gas CG, and the components separated by the separation column 2 are measured by the detector 3.

[Second Embodiment]
Next, a second embodiment of the gas chromatograph apparatus will be described as shown in FIG. The second embodiment is configured to continuously measure the concentrated sample gas SG1. That is, the concentrated sample gas SG1 discharged from the concentrator 1 is sent to the detector 3 and measured through the first discharge channel 5b without passing through the sampling valve SV or the like. As a result, the concentrated sample gas SG1 can be measured continuously rather than in pieces. In the second embodiment, a capillary tube (resistance tube) 2 ′ for flow rate control is provided in place of the separation column 2 for continuous measurement.

  In each said embodiment, although the gas discharged | emitted from the 1st discharge flow path 5b was measured, the gas discharged | emitted from the 2nd discharge flow path 7 can also be measured. That is, when the sample gas SG is mainly composed of argon, nitrogen or the like and hydrogen is the detection target gas, the permeated gas (hydrogen gas) SG2 discharged from the second discharge flow path 7 becomes the detection target gas. The permeate gas SG2 is measured.

  Thus, the sample gas discharged from the first discharge path 5b or the second discharge path 7 is a concentrated sample from the first discharge path 5b when the main component gas is a low molecule (for example, hydrogen) depending on the size of the molecule. When the gas (for example, argon or nitrogen) is discharged and the main component gas is a polymer (for example, argon or nitrogen), the concentrated sample gas (for example, hydrogen) is discharged from the second discharge path 7. By selecting the measurement channel, any concentrated sample gas can be easily introduced into the analyzer.

  Further, even if the sample gas to be concentrated is not limited to a single component but a plurality of components, the concentrated sample gas can be concentrated by the non-permeating action through the separation filter.

FIG. 5 shows an example of a chromatogram obtained by the gas chromatograph apparatus of FIG. In this data, measurement was performed on a sample gas containing hydrogen as a main component and approximately 20 ppm of Ar, N ₂ , CH ₄ , and CO as low concentration measurement components. As a result of measurement after concentration at a concentration rate of about 20 times, the measured value of Ar was about 395 ppm, which coincided with the concentration rate (the same applies to other components). Therefore, while the detection sensitivity of a gas chromatograph is generally about 1 ppm, even if the concentration is below the lower limit of detection, for example, 0.1 ppm or less, the concentration rate can be easily changed by changing the flow rate ratio to 20 to 100 times. Can be measured as a measurable concentration range. The concentration rate can be determined by trial according to the component of the sample gas, the performance of the detector, etc., and in consideration of the consumption gas flow rate, to a concentration that can be measured with the highest accuracy.

DESCRIPTION OF SYMBOLS 1 Concentrator 2 Separation column 2 'Capillary tube 3 Detector 1a One end 1b of a storage tube The other end 1c of a storage tube The outer peripheral surface 10 of a storage tube Non-porous membrane hollow fiber 11 Storage tube 12 Separation filter SG Sample gas

Claims (6)

  In a gas analyzer that performs measurement by concentrating a sample gas with a concentrator, the concentrator includes a separation filter in which a number of non-porous membrane hollow fibers are bundled, and the sample gas is passed through the separation filter. A gas analyzer characterized by being a concentrated sample gas.   The separation filter is housed in a housing tube, the longitudinal direction of the separation filter is arranged in the longitudinal direction of the housing tube, and the housing tube is used for supplying the sample gas to one end in the longitudinal direction. A first discharge channel that discharges the sample gas to the other end in the longitudinal direction; and a second discharge channel that discharges the sample gas to the outer peripheral surface of the supply channel. Alternatively, the gas analyzer according to claim 1, wherein the concentrated sample gas discharged from the second discharge channel is measured.   The gas analyzer according to claim 2, wherein the concentrated sample gas is continuously introduced into an analyzer and continuously measured.   In a gas analysis method for measuring by concentrating a sample gas with a concentrator, a concentrator equipped with a separation filter in which a large number of non-porous membrane hollow fibers are bundled is prepared, and the sample gas is passed through the separation filter for concentration. A gas analysis method characterized by using a sample gas.   The separation filter is housed in a housing tube, the longitudinal direction of the separation filter is arranged in the longitudinal direction of the housing tube, and the housing tube is a supply flow for supplying the sample gas to one end in the longitudinal direction. A first discharge flow path for discharging the sample gas at the other end in the longitudinal direction, and a second discharge flow path for discharging the sample gas on the outer peripheral surface thereof, the first discharge flow path or the The gas analysis method according to claim 4, wherein the concentrated sample gas discharged from the second discharge channel is measured.   The gas analysis method according to claim 5, wherein the concentrated sample gas is continuously introduced into an analyzer and continuously measured.

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