JP3778442B2 - Gas sampling method and sampling device - Google Patents

Description

【００２３】
消化ガス中のシロキサン濃度を第１表に示す。
【００２４】
実施例２
図２に示すガス試料採取装置を用いたこと以外は、実施例１と同じ条件で嫌気性消化ガス中に含まれるシロキサン類を捕集し、定量分析した。吸収瓶のガス導入管径（内径）は６ｍｍ（２Ａ、５共に）である。（比較例１も同じ）
消化ガス中のシロキサン濃度を第１表に示す。
【００２５】
比較例１
冷媒として氷を用いた他は、実施例１と同じ条件で嫌気性消化ガス中に含まれるシロキサン類を捕集し、定量分析した。
消化ガス中のシロキサン濃度を第１表に示す。シロキサン濃度は実施例１及び実施例２に比べて低かった。
【００２６】
比較例２
前段吸収瓶に後段吸収瓶と同じものを用いた以外は、実施例１と同じ条件で嫌気性消化ガス中に含まれるシロキサン類を捕集し、定量分析した。
消化ガスの試料採取開始直後から、前段吸収瓶のガス試料導入管内に水分が凝固・付着した。３０分程度経過時点で前段吸収瓶の通気抵抗が上昇し始め、１時間経過時点で完全に流路が閉塞し、ガス採取が不可能になった。
【００２７】
【表１】

【００２８】
【発明の効果】
本発明に係るガス試料採取方法及び装置によれば、ガス試料中に大量の水分が含まれている場合でも吸収瓶の構造を、水分の凝固によってガス導入管内が閉塞しないように工夫しているため、氷点以下の低温の冷浴を用いて分析対象成分の捕集効率を上げることができ、その結果、吸収瓶の数を削減することができるため、極めて簡便な装置で、容易に試料ガス中に含まれる成分を、損失なく、正確に捕集できる。
【図面の簡単な説明】
【図１】本発明のガス試料採取装置の一例を示す模式図。
【図２】本発明のガス試料採取装置の別の例を示す模式図。
【図３】従来のガス試料採取装置の例を示す模式図。
【符号の説明】
１ 前段吸収瓶
２ ガス導入管
２Ａ ガス導入管
３ 吸収液
４ 後段吸収瓶
５ ガス導入管
６ 試料ガス
７ 流量調整器
８ 吸引ポンプ
９ ガスメーター
１０ 冷媒
１１ 冷却槽[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas sampling method and a sampling device, and more particularly to a gas sampling method and a sampling device that can accurately collect an analysis target component without loss without being affected by moisture in a wet gas. .
[0002]
[Prior art]
When analyzing the specific gaseous component in the exhaust gas discharged into the flue, chimney, duct, introduce the sample gas into the absorption bottle containing the absorbing liquid, collect the specific gaseous component in the absorbing liquid, An analysis sample solution is used (Japanese Industrial Standard K0095-1999 “Exhaust gas sampling method”).
As shown in FIG. 3, the absorption bottle 1 is filled with the absorption liquid 3, and the sample gas is introduced into the absorption liquid 3 from the gas introduction pipe 2, and the flow rate is adjusted at the end of the absorption bottle. A vessel 7, a suction pump 8, a gas meter 9 and the like are sequentially connected. In FIG. 3, the absorption bottles are provided in two stages, 4 is a rear-stage absorption bottle, 5 is a gas introduction pipe of the rear-stage absorption bottle, and 6 is a gas sample.
[0003]
In such a conventional apparatus, the following measures are taken in order to accurately collect the analysis target component without loss.
(1) Connect the absorption bottles in multiple stages in series.
(2) The absorption bottle is put into a cooling tank or a cooling chamber and cooled.
[0004]
[Problems to be solved by the invention]
The above-described measures are effective in increasing the collection performance of the analysis target component, and the collection efficiency increases as the number of absorption bottles connected in series is increased and the temperature of the absorption liquid is lowered. However, if the number of absorption bottles is increased in order to improve the collection performance, not only the apparatus becomes excessive, but a large amount of absorption liquid is required, and the collection work and analysis work become complicated. Many. On the other hand, by reducing the temperature of the absorption liquid, it is possible to demonstrate high collection performance with a small number of absorption bottles, but in practice, collection may be insufficient at a cooling temperature of about an ice bath. In many cases, it is desirable to cool to a lower temperature using dry ice or the like. Cooling with dry ice can be carried out without problems using conventional collection methods and devices when the gas sample is dry gas, but when the gas sample is a wet gas containing a large amount of mist or water vapor, an absorption bottle can be used. In particular, there is a fatal problem that moisture is solidified and clogged in a narrow flow path such as in a gas introduction pipe, making it impossible to introduce gas.
[0005]
Conventionally, when there is such a problem, it is common to provide a dehumidifying means using a dehumidifying agent such as calcium chloride or magnesium perchlorate in the front stage of the absorption bottle, but this method is In addition to the absorption means for the target component, a separate dehumidifying means is required, and there is a problem that complicates the sampling device and the sampling method. In addition, many of the target components are trapped in the dehumidifying agent together with moisture, and it is not easy to recover the components trapped in the dehumidifying agent. It was. On the other hand, in the case of a component that is difficult to be captured by the dehumidifying agent, preliminary verification for confirming that it is not captured is indispensable, and this is a time-consuming method.
[0006]
The present invention has been made in view of the above circumstances, and even when the gas sample is a wet gas, a sample gas sampling method capable of accurately and simply collecting the analysis target component contained in the gas without loss and It is an object to provide an apparatus.
[0007]
[Means for Solving the Problems]
The present invention was able to solve the above problems by the following means.
(1) The wet gas is introduced from the introduction passage, and the moisture in the gas is solidified while being cooled below the freezing point, and the first absorption means for collecting the target component in the gas is passed through the first absorption means. Gas for collecting the target component that was introduced through the gas introduction passage provided in the subsequent stage and could not be collected by the second absorption means under the temperature condition below the freezing point, and for analyzing the component contained in the wet gas In the sampling method of
The method of collecting a gas sample, wherein the wet gas at the front stage flows through a wider introduction passage than the gas introduction passage at the rear stage and is introduced into the first absorption means.
[0008]
(2) The first absorption part that cools the gas below the freezing point, solidifies the moisture in the gas, and collects the target component in the gas, and the target component that cannot be collected by the first absorption part. In the gas sampling device for analyzing components contained in the wet gas, the second absorption unit for collecting under a temperature condition below the freezing point, and a gas suction means are provided in series.
An apparatus for collecting a gas sample, characterized in that an introduction passage for a gas introduced into the first absorption section is wider than a gas introduction passage in the second absorption section.
[0009]
(3) The gas sample according to (2), wherein the gas passage introduced into the first absorption section is a pipe having a diameter larger than the diameter of the gas introduction pipe into the second absorption section. Sampling device.
(4) Of the first absorption part and the second absorption part, only the second absorption part or any of the absorption parts is configured such that the gas and the absorption medium can be in contact with each other. The gas sample collecting device according to (2) or (3).
(5) The gas sample collection device according to any one of (2) to (4), wherein both the first and second absorption parts are absorption bottles.
(6) The absorption bottle used in the first absorption part is connected in the reverse direction with respect to the gas flow direction, and the absorption bottle used in the second absorption part is connected in the forward direction. The gas sample collecting apparatus according to (4) or (5), which is characterized in that
[0010]
Furthermore, in the apparatus of the present invention, preferred embodiments are as follows.
( 7 ) The diameter of the introduction pipe of the first absorption part is 10 mm or more, and the second absorption part is an absorption bottle with high absorption performance that is widely used. Gas sample collection device.
[0011]
In this way, by devising the structure of the absorption device such as an absorption bottle so that the gas flow path does not block even when moisture in the wet gas solidifies and adheres, The collection efficiency can be increased, and as a result, the number of absorption bottles can be reduced. Therefore, it is possible to easily collect a gas sample with a very simple apparatus with high efficiency.
[0012]
Next, the contents of the present invention will be described in detail.
If the gas introduction tube diameter (inner diameter) of the absorption bottle or the like is too small, the ventilation resistance increases and there is a risk of clogging due to a solid component contained in the gas. On the contrary, if the tube diameter is too large, the contact between the absorbing liquid and the gas introduced into the absorbing liquid is worsened, and there is a concern that the collection efficiency of the target component may be lowered. Pipes of millimeters to several tens of millimeters are used. However, in the case of such a tube diameter, when a humid gas containing a large amount of mist or water vapor is introduced over a long period of time under a temperature condition below the freezing point, the solidified water accumulates in the tube and becomes clogged. Therefore, depending on the amount of gas water vapor and the gas introduction time, in the absorption bottle (hereinafter referred to as the pre-stage absorption bottle) in the first absorption means of the present invention, the diameter of the gas introduction pipe is 10 mm or more. Is preferable, and it is more preferable that it is 20 mm or more. When the tube diameter is increased in this way, the risk of clogging is reduced even if the condensed water is accumulated, but the contact efficiency between the sample gas and the absorbing liquid is deteriorated as described above.
[0013]
However, from the actual experience of the present inventors so far, even when the contact efficiency between the sample gas and the absorbing liquid is somewhat sacrificed, by maintaining a low temperature condition below the freezing point, high collection performance can be demonstrated. I found that there are many. Even if high collection performance cannot be obtained in the front-stage absorption bottle, the most important role of the front-stage absorption bottle in the present invention is to coagulate and remove moisture in the gas. Efficiency is not a big problem. The target component that could not be collected in the front absorption bottle is introduced into the second absorption means (hereinafter referred to as the rear absorption bottle), but most of the water contained in the gas is in the front absorption bottle. Since it has already been removed, there is no fear of blockage of the flow path due to moisture coagulation in the latter-stage absorption bottle. Therefore, a gas sample can be collected while cooling to a low temperature below the freezing point using a generally used absorption bottle with high absorption performance.
[0014]
If satisfactory sample collection is not possible with a series of two front-stage absorption bottles and one rear-stage absorption bottle, the front-stage absorption bottles and / or the rear-stage absorption bottles may be added in multiple stages as necessary. . The number of connected front-stage absorption bottles may be determined based on the removal performance of moisture in the gas, and the number of connected rear-stage absorption bottles may be determined based on the collection performance of the target component.
[0015]
In the present invention, it is not always necessary to introduce gas into the absorption medium. For example, an absorption bottle containing nothing can be cooled at low temperature, a gas sample is introduced, the target component is once attached to the inner wall of the absorption bottle, etc., and the liquid in the bottle is washed with a small amount of absorption liquid when the gas sample is introduced. By doing so, a sample solution of the target component can be obtained. Moreover, when using an absorption medium, there is no restriction | limiting in particular in the kind of medium, For example, it may be a liquid or something like a bead-like solid. For this reason, the “absorbing medium” as used in the present invention is not limited to only performing narrow absorption, but also includes a solid medium that performs adsorption. In the case of a liquid, it may be solidified during sampling by a cold bath as long as it does not hinder gas flow, but it is preferable that it does not solidify.
[0016]
Since the present invention is made so as not to block the gas flow path due to the coagulation of water, there is no limitation on the cooling temperature, and various refrigerants can be used. Liquid oxygen, liquid argon, liquid nitrogen, or the like can be used as long as the absorption device can withstand the cooling temperature, as well as water and dry ice with a reduced freezing point. However, if the temperature is such that the target component and coexisting components in the gas are liquefied or solidified, it is not preferable because the gas flow path is clogged or insufficiently collected.
[0017]
In order to carry out the method of the present invention in the simplest manner, an absorption bottle that is widely used for both the front-stage absorption bottle and the rear-stage absorption bottle is used. May be connected in the forward direction to constitute a gas sampling device. By connecting the front absorption bottle in the reverse direction, the gas is directly introduced into the main body of the absorption bottle without going through the cooled narrow introduction pipe near the bottom of the absorption bottle. That is, the flow path in which the gas is first cooled is not in the gas introduction pipe, but is a wide flow path outside the gas introduction pipe or inside the absorption bottle body, and moisture in the gas is absorbed in the inner wall of the absorption bottle body or the gas introduction pipe. Adhere to the outer wall. After that, the gas flows in the opposite direction through the narrow pipe that was originally the gas introduction part and is discharged from the upstream absorption bottle. At this point, the gas has already been dehumidified, so that the moisture inside the introduction pipe has solidified. It will not be blocked by the accumulation of. In this method, although it is difficult to blow the sample gas into the absorption liquid in the upstream absorption bottle (if the lower end of the thin pipe is immersed in the absorption liquid, the absorption liquid passes through the thin pipe due to the sample gas flowing out of the thin pipe. As described above, since the temperature is extremely low as described above, most of the target components are collected in the absorption bottle together with moisture without using the absorption liquid. The components collected together with moisture in such a form are washed in the former absorption bottle with the same kind of absorption liquid as the absorption liquid in the latter-stage absorption bottle at the low temperature condition after the gas sampling is finished, and this washing liquid is absorbed in the latter-stage. What is necessary is just to use for analysis as a sample solution with the absorption liquid in a bottle.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. The same components as those shown in FIG. 3 are denoted by the same reference numerals.
FIG. 1 is a schematic view showing an example of a gas sampling device of the present invention.
The gas sampling apparatus has a configuration in which a front absorption bottle 1, a rear absorption bottle 4, a flow rate adjustment meter 7, a suction pump 8, and a gas meter 9 are connected in series. The front-stage absorption bottle 1 and the rear-stage absorption bottle 4 are cooled in the cooling tank 11, and the absorption liquid 3 is contained in each absorption bottle. The gas inlet pipe 2 of the front-stage absorption bottle 1 has a large diameter in order to prevent the channel from being blocked due to the solidification of moisture in the gas. The gas sample 6 is first introduced into the front-stage absorption bottle 1 by the suction pump 8, and moisture and analysis target components in the gas are absorbed in the bottle or the absorption liquid 3. Next, the analysis target component introduced into the rear-stage absorption bottle 4 and not collected by the front-stage absorption bottle 1 is collected in the absorption liquid 3 of the rear-stage absorption bottle 4. In FIG. 1, 10 is a refrigerant.
[0019]
FIG. 2 is a schematic view showing another example of the gas sampling device of the present invention.
The gas sampling apparatus has a configuration in which a front absorption bottle 1, a rear absorption bottle 4, a flow rate adjustment meter 7, a suction pump 8, and a gas meter 9 are connected in series. The front-stage absorption bottle 1 and the rear-stage absorption bottle 4 are cooled in the cooling tank 11, and the absorbent 3 is contained only in the rear-stage absorption bottle 4. The pre-stage absorption bottle 1 is installed in the opposite direction to the gas flow direction in order to prevent the channel from being blocked by the coagulation of moisture in the gas. For this reason, the gas introduction pipe 2A in the front-stage absorption bottle 1 is thin and short, and the absorption liquid 3 is not contained in the absorption bottle 1, so that the gas sample is not blown into the absorption liquid 3. The gas sample 6 of the wet gas is first introduced into the upstream absorption bottle 1 by the suction pump 8, and the moisture and the analysis target component in the gas sample 6 are absorbed in the bottle 1. Next, the analysis target component introduced into the rear-stage absorption bottle 4 and not collected by the front-stage absorption bottle 1 is collected in the absorption liquid 3 of the rear-stage absorption bottle 4.
[0020]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
[0021]
Example 1
Using the gas sampling device shown in FIG. 1, trace components (siloxanes) contained in the anaerobic digestion gas were collected and quantitatively analyzed using a gas chromatograph mass spectrometer. Gas properties and gas sampling conditions are as follows.
[0022]

[0023]
Table 1 shows the siloxane concentration in the digestion gas.
[0024]
Example 2
The siloxanes contained in the anaerobic digestion gas were collected and quantitatively analyzed under the same conditions as in Example 1 except that the gas sampling apparatus shown in FIG. 2 was used. The gas inlet tube diameter (inner diameter) of the absorption bottle is 6 mm (both 2A and 5). (Comparative example 1 is the same)
Table 1 shows the siloxane concentration in the digestion gas.
[0025]
Comparative Example 1
Except for using ice as the refrigerant, siloxanes contained in the anaerobic digestion gas were collected under the same conditions as in Example 1 and quantitatively analyzed.
Table 1 shows the siloxane concentration in the digestion gas. The siloxane concentration was lower than that in Example 1 and Example 2.
[0026]
Comparative Example 2
The siloxanes contained in the anaerobic digestion gas were collected and quantitatively analyzed under the same conditions as in Example 1 except that the same absorbent bottle as that used in the latter stage was used.
Immediately after the start of sampling of the digestion gas, moisture coagulated and adhered in the gas sample introduction tube of the former absorption bottle. When about 30 minutes passed, the ventilation resistance of the pre-stage absorption bottle began to rise, and when 1 hour passed, the flow path was completely blocked and gas sampling became impossible.
[0027]
[Table 1]

[0028]
【The invention's effect】
According to the gas sample collection method and apparatus according to the present invention, the structure of the absorption bottle is devised so that the inside of the gas introduction pipe is not blocked by the solidification of the moisture even when the gas sample contains a large amount of moisture. Therefore, it is possible to increase the collection efficiency of components to be analyzed using a cold bath below the freezing point, and as a result, it is possible to reduce the number of absorption bottles. The components contained in it can be collected accurately without loss.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an example of a gas sampling device of the present invention.
FIG. 2 is a schematic view showing another example of the gas sampling device of the present invention.
FIG. 3 is a schematic diagram showing an example of a conventional gas sampling device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 First stage absorption bottle 2 Gas introduction pipe 2A Gas introduction pipe 3 Absorption liquid 4 Later stage absorption bottle 5 Gas introduction pipe 6 Sample gas 7 Flow rate regulator 8 Suction pump 9 Gas meter 10 Refrigerant 11 Cooling tank

Claims (6)

The wet gas is introduced from the introduction passage and cooled to below the freezing point to solidify the moisture in the gas, and after passing through the first absorption means in the previous stage for collecting the target component in the gas, the gas is provided in the subsequent stage. Gas sample for analyzing the components contained in the wet gas by collecting the target components that could not be collected after being introduced through the gas introduction passage by the second absorption means under the temperature condition below the freezing point. In the method
  The method of collecting a gas sample, wherein the wet gas at the front stage flows through the introduction passage wider than the gas introduction passage at the rear stage and is introduced into the first absorption means. The first absorption part that cools the gas to below the freezing point, solidifies the moisture in the gas and collects the target component in the gas, and the target component that could not be collected by the first absorption part is below the freezing point In a gas sampling device for analyzing a component contained in a wet gas, which is provided with a second absorption section that collects under temperature conditions and a gas suction means in series.
  An apparatus for collecting a gas sample, characterized in that a gas introduction passage into the first absorption section is wider than a gas introduction passage in the second absorption section. 3. The gas sample collecting apparatus according to claim 2, wherein the gas passage introduced into the first absorption section is a pipe having a diameter larger than a diameter of a gas introduction pipe into the second absorption section. The first absorption unit and the second absorption unit are configured such that only the second absorption unit or any of the absorption units can contact the gas and the absorption medium. The gas sample collecting device according to 2 or 3. The gas sample collection device according to any one of claims 2 to 4, wherein the first and second absorption parts are both absorption bottles. The absorption bottle used in the first absorption unit is connected in the reverse direction to the gas flow direction, and the absorption bottle used in the second absorption unit is connected in the forward direction. The gas sample collecting device according to claim 4 or 5.

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