JP2002131228A - Laser spectroscopic analysis method - Google Patents
Laser spectroscopic analysis methodInfo
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- JP2002131228A JP2002131228A JP2000325100A JP2000325100A JP2002131228A JP 2002131228 A JP2002131228 A JP 2002131228A JP 2000325100 A JP2000325100 A JP 2000325100A JP 2000325100 A JP2000325100 A JP 2000325100A JP 2002131228 A JP2002131228 A JP 2002131228A
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- hydrogen chloride
- concentration
- absorption
- water
- laser
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、レーザ分光分析方
法に関し、詳しくは、多成分ガスの濃度、例えば、ガス
中の水分濃度と塩化水素濃度とを容易に測定できるレー
ザ分光分析方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser spectroscopic analysis method, and more particularly to a laser spectroscopic analysis method capable of easily measuring the concentration of a multi-component gas, for example, the concentration of water and hydrogen chloride in the gas.
【０００２】[0002]
【従来の技術】近年、環境保護の面から、ゴミ焼却にお
ける排気ガス及びその排気口近傍の大気中の有害成分の
管理が重要になっている。ゴミ焼却の排気ガスには、規
制対象となる有害成分の他に数１０％の水分が含まれて
いる。このような水分を多く含むガス中の有害成分濃度
を分析する場合、排気ガスの一部を取り出して規定濃度
の水溶液にバブリングさせて分析する湿式分析方法が採
られていた。2. Description of the Related Art In recent years, from the viewpoint of environmental protection, it has become important to control exhaust gas in garbage incineration and harmful components in the atmosphere near the exhaust port. Exhaust gas from garbage incineration contains tens of percent of water in addition to harmful components to be regulated. In the case of analyzing the concentration of harmful components in such a gas containing a large amount of water, a wet analysis method has been adopted in which a part of exhaust gas is taken out and bubbled and analyzed with an aqueous solution having a specified concentration.
【０００３】[0003]
【発明が解決しようとする課題】しかし、その濃度は、
排気ガス中から水分を除去した場合を母集団として算出
する必要があり、前記湿式分析方法では、別途水分濃度
を計測する必要があった。一方、乾式のガス濃度分析方
法としては、ＦＴ−ＩＲ法が広く知られている。ＦＴ−
ＩＲ法は、ガス濃度を同時に分析することができるとい
う利点を有するものの、専門知識が必要であり、分析に
かなりの費用を要するという欠点を有している。また、
この方法では、水分の吸収強度が大きいので、数１０％
の水分を計測すると、そのスペクトルに微量な有害成分
のスペクトルが重なるため、有害成分の定量が非常に困
難であった。However, the concentration is
It was necessary to calculate a case where water was removed from the exhaust gas as a population, and in the wet analysis method, it was necessary to separately measure the water concentration. On the other hand, the FT-IR method is widely known as a dry gas concentration analysis method. FT-
Although the IR method has an advantage that gas concentrations can be analyzed at the same time, it has a disadvantage that expertise is required and the analysis is considerably expensive. Also,
In this method, since the absorption strength of moisture is large, several tens%
When the water content was measured, the spectrum of a trace amount of the harmful component was superimposed on the spectrum, so that it was very difficult to quantify the harmful component.
【０００４】そこで本発明は、レーザ分光法の利点を生
かし、単一のレーザ光源で、複数成分の濃度分析を容易
にかつ確実に行うことができるレーザ分光分析方法を提
供することを目的としている。Accordingly, an object of the present invention is to provide a laser spectroscopic analysis method which can easily and reliably perform the concentration analysis of a plurality of components with a single laser light source, taking advantage of laser spectroscopy. .
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するた
め、本発明のレーザ分光分析方法は、ガス中の複数成分
の濃度分析を、単一の単一波長発振用半導体レーザー光
源から発振されたレーザー光を用いて得られた吸収スペ
クトルに基づいて測定することを特徴としている。In order to achieve the above-mentioned object, a laser spectroscopic analysis method according to the present invention performs a concentration analysis of a plurality of components in a gas by oscillating the concentration from a single semiconductor laser light source for single wavelength oscillation. It is characterized in that measurement is performed based on an absorption spectrum obtained using laser light.
【０００６】また、本発明のレーザ分光分析方法は、前
記複数成分が、少なくともクラスターを形成する成分を
含んでいるときに極めて有効であり、特に、１７３０〜
１７６０ｎｍの単一の単一波長発振用レーザー光源を用
いて試料ガス中の水分及び塩化水素の濃度を分析するの
に最適である。[0006] The laser spectroscopy method of the present invention is extremely effective when the plurality of components include at least components forming clusters.
It is most suitable for analyzing the concentration of moisture and hydrogen chloride in a sample gas using a single single-wavelength laser light source of 1760 nm.
【０００７】さらに、本発明のレーザ分光分析方法にお
いては、前記複数成分をそれぞれ単独に計測した吸収ス
ペクトルの半値半幅とその吸収強度とを基準とし、複数
成分を計測したときに得られた吸収スペクトルの半値半
幅とその吸収強度とから複数成分の濃度をそれぞれ換算
補正することを特徴としている。Further, in the laser spectroscopic analysis method of the present invention, the absorption spectrum obtained when measuring a plurality of components is measured on the basis of the half-width at half maximum of the absorption spectrum of each of the plurality of components independently measured and the absorption intensity thereof. The concentration of a plurality of components is converted and corrected based on the half-width at half maximum and the absorption intensity.
【０００８】すなわち、本発明のレーザ分光分析方法
は、前述のゴミ焼却における排気ガスのように多量の水
分を含むガス中の塩化水素やアンモニア、大気中の各種
成分の濃度をレーザ光の吸収スペクトルにより分析する
レーザ分光分析法であって、前記レーザ光の発振源とし
て、波長帯域が１７３０〜１７６０ｎｍの単一波長発振
用半導体レーザ光源を使用し、複数成分の濃度分析を単
一のレーザ光源からのレーザ光の吸収スペクトルにより
行うものである。[0008] That is, the laser spectroscopic analysis method of the present invention determines the concentration of hydrogen chloride and ammonia in a gas containing a large amount of water, such as the exhaust gas in the above-mentioned refuse incineration, and the concentration of various components in the atmosphere by the absorption spectrum of laser light. A semiconductor laser light source for single-wavelength oscillation having a wavelength band of 1730 to 1760 nm as an oscillation source of the laser light, and analyzing the concentration of a plurality of components from a single laser light source. This is performed based on the absorption spectrum of the laser light.
【０００９】以下、塩化水素及び水分の濃度を同時に測
定する場合を例に挙げて本発明を説明する。まず、図１
は、波長１７３０〜１７６０ｎｍにおける塩化水素及び
水分の吸収線を示している。図１に示すように、この波
長域には、塩化水素及び水分の多くの吸収線が存在す
る。これらの中から近接する吸収線を使用すれば、単一
のレーザ光源で塩化水素と水分とを同時に計測すること
が可能である。また、塩化水素の吸収強度に比べて水分
の吸収強度が２〜４桁小さいことから、高濃度水分と微
量塩化水素とを同程度の感度で計測することが可能であ
る。特に、１７４７ｎｍ付近にある塩化水素の吸収線
は、水分の吸収線と極めて近接して存在しており、吸収
強度が約３桁大きいことから、数１０％程度の高濃度水
分と数１０ｐｐｍ程度の塩化水素とを容易に、かつ、一
つの検出器だけで計測することができる。当然、吸収線
の組み合せを変えれば、濃度の組み合せが異なる場合で
も同様の計測ができる。The present invention will be described below with reference to an example in which the concentrations of hydrogen chloride and water are measured simultaneously. First, FIG.
Indicates absorption lines of hydrogen chloride and water at a wavelength of 1730 to 1760 nm. As shown in FIG. 1, there are many absorption lines of hydrogen chloride and moisture in this wavelength range. If an absorption line that is close to these is used, it is possible to measure hydrogen chloride and moisture simultaneously with a single laser light source. Further, since the absorption intensity of water is two to four orders of magnitude lower than the absorption intensity of hydrogen chloride, it is possible to measure high-concentration water and trace amounts of hydrogen chloride with the same sensitivity. In particular, the absorption line of hydrogen chloride near 1747 nm exists very close to the absorption line of moisture, and the absorption intensity is about three orders of magnitude higher. Hydrogen chloride can be easily measured with only one detector. Of course, if the combination of the absorption lines is changed, the same measurement can be performed even when the combination of the concentrations is different.
【００１０】通常、このように近接した吸収を計測する
場合、その吸収線が重なって計測結果に多くの誤差を含
む場合がある。図２は、塩化水素及び水をそれぞれ単独
で計測したときと、塩化水素と水とを同時に計測したと
きとの２次微分吸収スペクトルを示している。なお、計
測圧力は７０Ｔｏｒｒで一定としており、ベースガスは
窒素である。Normally, when measuring such close absorption, the absorption lines may overlap and the measurement result may include many errors. FIG. 2 shows secondary differential absorption spectra when hydrogen chloride and water were measured independently, and when hydrogen chloride and water were measured simultaneously. The measurement pressure was constant at 70 Torr, and the base gas was nitrogen.
【００１１】図２における横軸は、半導体レーザへの注
入電流を示しているが、レーザの発振波長と同義であ
る。塩化水素及び水分の単独の吸収スペクトル位置と、
塩化水素と水分とを混合して計測したときの吸収スペク
トルの位置とがそれぞれ良く一致していることがわか
る。また、計測圧力を７０Ｔｏｒｒとすることにより、
二つの吸収スペクトルが分離され、定量が容易になって
いることがわかる。ここでは、一例として１７４７ｎｍ
付近での吸収を例示したが、使用する半導体レーザのチ
ューニング特性、即ち注入電流値に対する発振波長の変
化割合に応じて適宜波長を変えてもよい。The horizontal axis in FIG. 2 shows the injection current into the semiconductor laser, which is synonymous with the laser oscillation wavelength. The sole absorption spectrum positions of hydrogen chloride and water;
It can be seen that the positions of the absorption spectra obtained by mixing and measuring hydrogen chloride and water are in good agreement with each other. Also, by setting the measured pressure to 70 Torr,
It can be seen that the two absorption spectra were separated, making the quantification easy. Here, as an example, 1747 nm
Although the absorption in the vicinity has been exemplified, the wavelength may be appropriately changed according to the tuning characteristics of the semiconductor laser to be used, that is, the change ratio of the oscillation wavelength to the injection current value.
【００１２】また、図３は、塩化水素と水分とを大気圧
下で計測したときの吸収スペクトルを示している。吸収
スペクトルを検出する際に二次微分吸収成分のみを検出
することにより、吸収スペクトルがより急峻になり、こ
のような大気圧下での計測においても、両者の吸収スペ
クトルを分離することができる。FIG. 3 shows an absorption spectrum when hydrogen chloride and water are measured under atmospheric pressure. By detecting only the second derivative absorption component when detecting the absorption spectrum, the absorption spectrum becomes steeper, and even in the measurement under the atmospheric pressure, the two absorption spectra can be separated.
【００１３】一方、塩化水素と水分とが混合している場
合、それぞれの成分が極性を有しているため、吸収スペ
クトル強度が変動する場合がある。図４は、窒素中に塩
化水素と水とが共存する状態で、１００Ｔｏｒｒでセル
を封止したときの塩化水素の吸収強度と半値半幅との時
間依存性を示している。図中の「白丸」は塩化水素の吸
収強度比を示し、「黒丸」は塩化水素の吸収スペクトル
における半値半幅を示している。時間ａでは、約１５０
ｐｐｍの塩化水素のみがセル内に存在するため、吸収強
度比は約１．０となり、半値半幅も０．８ｍＡ程度で一
定値となっている。時間ｂでは塩化水素の供給を停止し
て水分を供給し、塩化水素が検出されなくなり、水分の
吸収強度が安定したことを確認してから時間ｃに進み、
セル内を１５０ｐｐｍの塩化水素と数％の水分とを含む
状態としてセルを封止した。On the other hand, when hydrogen chloride and water are mixed, the absorption spectrum intensity may fluctuate because each component has polarity. FIG. 4 shows the time dependence of the absorption intensity of hydrogen chloride and the half width at half maximum when the cell is sealed at 100 Torr in a state where hydrogen chloride and water coexist in nitrogen. "White circles" in the figure indicate the absorption intensity ratio of hydrogen chloride, and "black circles" indicate the half width at half maximum in the absorption spectrum of hydrogen chloride. At time a, about 150
Since only ppm of hydrogen chloride exists in the cell, the absorption intensity ratio is about 1.0, and the half width at half maximum is about 0.8 mA, which is a constant value. At time b, the supply of hydrogen chloride is stopped to supply water, and after confirming that hydrogen chloride is no longer detected and the absorption intensity of water has stabilized, the process proceeds to time c,
The cell was sealed with the inside of the cell containing 150 ppm of hydrogen chloride and several percent of water.
【００１４】この時間ｃにおける塩化水素の吸収強度比
を見ると、時間の経過に伴って次第に減少し、０．１程
度まで低下している。一方、塩化水素の半値半幅は、時
間の経過に伴って徐々に大きくなり、約０．９５まで上
昇している。Looking at the ratio of the absorption intensity of hydrogen chloride at the time c, the ratio gradually decreases with the lapse of time and decreases to about 0.1. On the other hand, the half width at half maximum of hydrogen chloride gradually increases with time and rises to about 0.95.
【００１５】この現象は、水分子と塩化水素分子とが衝
突を繰り返すうちに水素結合によってクラスタを形成
し、数％の高濃度水分を含んだ状態で塩化水素を正確に
計測することが困難であることを示しており、例えば、
排気ガス中の塩化水素の濃度計測値が経時的に変動する
ため、正確な塩化水素濃度が計測できないことを示して
いる。[0015] This phenomenon is because water molecules and hydrogen chloride molecules repeatedly form a cluster by hydrogen bonding during repeated collisions, and it is difficult to accurately measure hydrogen chloride with a high concentration of water of several percent. That there is, for example,
This indicates that an accurate measurement of the concentration of hydrogen chloride cannot be performed because the measured value of the concentration of hydrogen chloride in the exhaust gas fluctuates with time.
【００１６】これに対しては、塩化水素の半値半幅の増
加関数より補正値を算出し、その補正値で吸収強度を補
正・換算すればよい。この計算は、計測結果に基づいて
人間が行ってもよいし、あらかじめ補正関数を記憶した
記憶回路と、半値半幅を検出演算する演算回路と、前記
２つの回路から補正値を求めて吸収強度を補正換算する
演算回路とで構成された電子回路を、レーザ分光分析装
置に組み込んで濃度を算出してもよい。なお、計測圧力
によって吸収強度、半値半幅、補正関数は異なるので、
計測圧力に応じてそれらの値を変更することが望まし
い。For this purpose, a correction value may be calculated from an increasing function of the half width at half maximum of hydrogen chloride, and the absorption intensity may be corrected and converted based on the correction value. This calculation may be performed by a human based on the measurement result, or a storage circuit storing a correction function in advance, a calculation circuit for detecting and calculating a half width at half maximum, and a correction value obtained from the two circuits to obtain an absorption intensity. An electronic circuit including a correction conversion arithmetic circuit may be incorporated in a laser spectrometer to calculate the concentration. Note that the absorption intensity, half width at half maximum, and correction function differ depending on the measured pressure.
It is desirable to change those values according to the measured pressure.
【００１７】ここで、図５乃至図７により、前記補正値
の算出要領を説明する。まず、図５は、吸収スペクトル
におけるピークと半値幅とを説明するものであって、図
５に示すように、駆動電流を増加させていくと、直線Ａ
に示すように光検出器での検出強度はリニアに上昇して
行くが、その途中で特定の波長ν０の光を吸収する成分
が存在すると、その部分で光が吸収されるため、波長ν
０を中心とした波長範囲Δλでは、光検出器での検出強
度が曲線Ｂで示すように低下する。Here, the procedure for calculating the correction value will be described with reference to FIGS. First, FIG. 5 illustrates a peak and a half-value width in an absorption spectrum. As shown in FIG.
As shown in (2), the detection intensity of the photodetector increases linearly. However, if there is a component that absorbs light of a specific wavelength ν 0 in the middle, the light is absorbed in that part, so that the wavelength ν
In the wavelength range Δλ centered on 0 , the detection intensity of the photodetector decreases as shown by the curve B.
【００１８】この曲線Ｂにおける二次微分信号を算出す
ると、下方の曲線Ｃで示す一般的な吸収スペクトルが得
られる。なお、直線Ａ０は、直線Ａの二次微分信号を示
している。この曲線ＣのピークＰにおける吸収強度Ｉ
は、該ピークＰの波長範囲Δλにおける両側の最低値か
らの高さＩＬ，ＩＲとから Ｉ＝（ＩＬ＋ＩＲ）／２ という式で算出される。When the second derivative signal of the curve B is calculated, a general absorption spectrum shown by a lower curve C is obtained. Incidentally, the straight line A 0 indicates a second derivative signal of linear A. Absorption intensity I at peak P of curve C
The height I L from the lowest values of both sides in the wavelength range Δλ of the peak P, is calculated by the expression I = (I L + I R ) / 2 from the I R.
【００１９】このとき、この成分の濃度以外の条件が同
じならば、この成分の濃度は、ピークＰの面積Ｓ、すな
わち、 Ｓ＝（Ｉ×Δλ）／２ という式で求めた近似値に比例する。つまり、濃度以外
の条件が一定ならば波長範囲Δλが一定となるため、濃
度は吸収強度Ｉに比例することになる。At this time, if the conditions other than the concentration of this component are the same, the concentration of this component is proportional to the area S of the peak P, that is, the approximate value obtained by the equation S = (I × Δλ) / 2. I do. That is, if conditions other than the concentration are constant, the wavelength range Δλ is constant, and the concentration is proportional to the absorption intensity I.
【００２０】また、このピークＰにおける半値幅とは、
ピークＰの頂点からＩ／２下がった位置における波長幅
（Δν）であり、分布曲線の解析等で多く用いられてい
る半値半幅は、この半値幅Δνの半分、即ちΔν／２で
ある。The half width at the peak P is
This is the wavelength width (Δν) at a position that is I / 2 below the peak P, and the half width at half maximum that is often used in analysis of distribution curves and the like is half of this half width Δν, that is, Δν / 2.
【００２１】図６及び図７は、塩化水素の計測におい
て、試料ガス中の水分の有無によるピーク形状の相違を
示すものであり、図６は試料ガス中に水分が存在しない
か、ほとんど存在しない場合、図７は比較的多量の水分
が存在している場合を示している。FIGS. 6 and 7 show the difference in the peak shape depending on the presence or absence of moisture in the sample gas in the measurement of hydrogen chloride. FIG. 6 shows that the sample gas has no or almost no moisture. FIG. 7 shows a case where a relatively large amount of water is present.
【００２２】まず、図６に示すように、水分存在量が塩
化水素の計測に影響を与えない場合、上段の高濃度時の
ピークＰＡと下段の低濃度時のピークＰＢとから明らか
なように、各ピークＰＡ，ＰＢにおけるピーク高さ
ＩＡ，ＩＢに対するＩＡ／２，Ｉ Ｂ／２の位置の各半値
幅ΔνＡ，ΔνＢは等しくなり、それぞれのピーク面積
は塩化水素の濃度に比例したものとなる。すなわち、、
各ピークＰＡ，ＰＢにおけるピーク高さＩＡ，ＩＢを求
めるだけで塩化水素濃度を計測することができる。First, as shown in FIG.
If it does not affect the measurement of hydrogen hydride,
Peak PAAnd lower peak P at low concentrationBClear from
Thus, each peak PA, PBPeak height at
IA, IBI forA/ 2, I BEach half value at position / 2
Width ΔνA, ΔνBAre equal and the respective peak areas
Is proportional to the concentration of hydrogen chloride. That is,
Each peak PA, PBHeight I atA, IBSeeking
The concentration of hydrogen chloride can be measured.
【００２３】一方、図７に示すように、水分が塩化水素
の計測に影響を与える場合は、同一塩化水素濃度のとき
であっても、例えば、図６の上段のピークＰＡと同じ塩
化水素濃度であっても、水分の影響によって下段に示す
ような幅広のピークＰＣを描くことになる。Meanwhile, as shown in FIG. 7, when affecting the measurement of the moisture hydrogen chloride, even when the same hydrogen chloride concentration, for example, the same hydrogen chloride upper peak P A in FIG. 6 even concentration, would draw a wide peak P C as shown in the lower part under the influence of moisture.
【００２４】このように、塩化水素と水分とが共存して
いると、塩化水素がクラスター化して大きく（重く）な
り、吸収される波長範囲が広がるため、ピーク高さＩＣ
に対する半値幅ΔνＣの値が大きくなる。このとき、ピ
ーク面積が濃度に比例することから、半値幅ΔνＣの値
が半値幅ΔνＡより大きくなった分だけピーク高さＩ Ｃ
がピーク高さＩＡより小さくなる。Thus, when hydrogen chloride and water coexist,
Hydrogen chloride clusters and is large (heavy)
And the wavelength range to be absorbed is widened, so that the peak height IC
Half-width ΔνCIncreases. At this time,
Since the surface area is proportional to the concentration, the half width ΔνCThe value of the
Is the half width ΔνAThe peak height I by the larger amount C
Is the peak height IASmaller.
【００２５】すなわち、塩化水素の計測に影響を与える
量の水分が存在している場合には、塩化水素のピーク高
さ（吸収強度）のみから塩化水素量を算出すると、実際
の試料ガス中の塩化水素濃度よりも低く計測されること
になる。さらに、前記図４の時間ｃにおける吸収強度比
と半値半幅との関係で示したように、時間の経過に伴っ
て吸収強度が減少するとともに半値半幅が増大すること
から、吸収強度のみでは測定時間によっても計測値に大
きな誤差を招くことになる。That is, if there is an amount of water that affects the measurement of hydrogen chloride, the amount of hydrogen chloride is calculated only from the peak height (absorption intensity) of hydrogen chloride. It will be measured below the concentration of hydrogen chloride. Further, as shown by the relationship between the absorption intensity ratio and the half width at half maximum at time c in FIG. 4, the absorption intensity decreases with time and the half width at half maximum increases. Causes a large error in the measured value.
【００２６】したがって、前述のように、吸収強度（ピ
ーク高さ）と半値半幅とに基づいて塩化水素濃度を補正
することにより、水分を含む試料ガス中の塩化水素濃度
を正確に計測することが可能となる。Therefore, as described above, the hydrogen chloride concentration in the sample gas containing water can be accurately measured by correcting the hydrogen chloride concentration based on the absorption intensity (peak height) and the half width at half maximum. It becomes possible.
【００２７】[0027]
【実施例】周知のレーザ分析装置を使用し、その測定セ
ル内に、試料ガスとして１７０ｐｐｍの塩化水素と２％
の水分とを含む窒素ガスを圧力１００Ｔｏｒｒで通気し
た。レーザー光源には、１７４０ｎｍ帯に発振波長を有
し、０．００７ｎｍ／ｍＡのチューニング特性を持つ、
単一波長の分布帰還型の半導体レーザを使用した。半導
体レーザの温度は３１．７℃の一定に制御し、駆動のた
めの注入電流は４０ｍＡから７０ｍＡの範囲で０．１ｍ
Ａ幅で掃引した。また、二次微分吸収スペクトルを検出
するために周波数変調法を用い、このとき、変調振幅及
び変調周波数はそれぞれ４ｍＡ及び１０ｋＨｚとした。EXAMPLE Using a well-known laser analyzer, 170 ppm of hydrogen chloride and 2%
And a nitrogen gas containing water at a pressure of 100 Torr. The laser light source has an oscillation wavelength in the 1740 nm band and a tuning characteristic of 0.007 nm / mA.
A single-wavelength distributed feedback semiconductor laser was used. The temperature of the semiconductor laser is controlled to be constant at 31.7 ° C., and the injection current for driving is 0.1 m in the range of 40 mA to 70 mA.
Sweep was performed in A width. In addition, a frequency modulation method was used to detect the second-order differential absorption spectrum. At this time, the modulation amplitude and the modulation frequency were 4 mA and 10 kHz, respectively.
【００２８】そして、比較的多量の水分と混在したとき
における塩化水素の吸収強度及び半値半幅の状況を確認
するため、測定セル内に試料ガスを封じ切った状態とし
てから所定時間経過後に電流のスキャンを開始した。得
られた吸収スペクトルを図８に示す。Then, in order to confirm the state of the absorption intensity and half width at half maximum of hydrogen chloride when mixed with a relatively large amount of water, the current scan is performed after a predetermined time has passed since the sample gas was sealed in the measurement cell. Started. FIG. 8 shows the obtained absorption spectrum.
【００２９】図８から明らかなように、塩化水素の吸収
（注入電流：５０ｍＡ）と水分の吸収（注入電流：５７
ｍＡ）とが分離された状態で検出でき、塩化水素と水分
とが約２桁の濃度差があっても単一の検出器でそれぞれ
の吸収スペクトルを計測できることがわかる。一方、試
料ガス封じ切り後の経過時間が長いほど、塩化水素の吸
収強度が弱くなり、ピーク高さが低くなっていること、
及び、半値半幅は、時間の経過とともに大きくなってい
ることがわかる。また、水分に関してはピーク形状に変
化がないので、ピーク高さだけで濃度を測定できること
がわかる。As is apparent from FIG. 8, the absorption of hydrogen chloride (injection current: 50 mA) and the absorption of moisture (injection current: 57 mA).
mA) can be detected in a separated state, and it can be seen that even if there is a concentration difference of about two digits between hydrogen chloride and water, each absorption spectrum can be measured with a single detector. On the other hand, the longer the elapsed time after the sample gas was sealed, the weaker the absorption intensity of hydrogen chloride and the lower the peak height,
Also, it can be seen that the half width at half maximum increases with the passage of time. In addition, since there is no change in the peak shape with respect to moisture, it can be seen that the concentration can be measured only by the peak height.
【００３０】そして、塩化水素の吸収強度と半値半幅と
の関係から、水分と共存した状態での塩化水素における
半値半幅の増加関数を求め、試料ガス中の塩化水素濃度
及び水分濃度を種々変化させて検量線を作成した。その
結果、塩化水素濃度が１０〜１０００ｐｐｍ、水分濃度
範囲が１％から７０％の範囲において、直線性に優れた
検量線を得ることができた。Then, from the relationship between the absorption intensity of hydrogen chloride and the half width at half maximum, the increasing function of the half width at half maximum of hydrogen chloride in the presence of water was determined, and the hydrogen chloride concentration and the water concentration in the sample gas were varied. To create a calibration curve. As a result, a calibration curve having excellent linearity was obtained when the hydrogen chloride concentration was in the range of 10 to 1000 ppm and the water concentration was in the range of 1% to 70%.
【００３１】[0031]
【発明の効果】以上説明したように、本発明のレーザ分
光分析方法によれば、複数成分の分析を単一の半導体レ
ーザと単一の検出器とによって行うため、より容易で安
価に分析を行うことができる。また、高濃度の水分と微
量の塩化水素とが共存した状態で、塩化水素の吸収強度
が高濃度水分の影響で大きく変動しても、より正確に塩
化水素濃度を計測することができ、従来では困難であっ
たゴミ焼却の排ガス中に含まれる塩化水素の分析をその
水分濃度計測と同時に行うことが可能となる。As described above, according to the laser spectroscopy method of the present invention, a plurality of components are analyzed by a single semiconductor laser and a single detector. It can be carried out. In addition, even if the absorption intensity of hydrogen chloride fluctuates greatly due to the effect of high-concentration water in a state where high-concentration water and a small amount of hydrogen chloride coexist, hydrogen chloride concentration can be measured more accurately. This makes it difficult to analyze hydrogen chloride contained in exhaust gas from garbage incineration at the same time as measuring the water concentration.
【図１】 波長１７３０〜１７６０ｎｍにおける塩化水
素及び水分の吸収線を示す図である。FIG. 1 is a diagram showing absorption lines of hydrogen chloride and moisture at a wavelength of 1730 to 1760 nm.
【図２】 塩化水素及び水をそれぞれ単独で計測したと
きと、塩化水素と水とを同時に計測したときとの２次微
分吸収スペクトルを示す図である。FIG. 2 is a diagram showing second-order differential absorption spectra when hydrogen chloride and water are measured independently and when hydrogen chloride and water are measured simultaneously.
【図３】 塩化水素と水分とを大気圧下で計測したとき
の吸収スペクトルを示す図である。FIG. 3 is a diagram showing an absorption spectrum when hydrogen chloride and moisture are measured under atmospheric pressure.
【図４】 窒素中に塩化水素と水とが共存する状態で、
１００Ｔｏｒｒでセルを封止したときの塩化水素の吸収
強度と半値半幅との時間依存性を示す図である。Fig. 4 In a state where hydrogen chloride and water coexist in nitrogen,
It is a figure which shows the time dependence of the absorption intensity | strength of hydrogen chloride at the time of sealing a cell at 100 Torr, and half width at half maximum.
【図５】 吸収スペクトルにおけるピークと半値幅とを
説明する図である。FIG. 5 is a diagram illustrating a peak and a half width in an absorption spectrum.
【図６】 試料ガス中に水分が存在しないときの塩化水
素の濃度とピーク形状との関係を示す図である。FIG. 6 is a diagram showing the relationship between the concentration of hydrogen chloride and the peak shape when there is no moisture in the sample gas.
【図７】 試料ガス中に水分が存在しているときの塩化
水素の濃度とピーク形状との関係を示す図である。FIG. 7 is a diagram showing the relationship between the concentration of hydrogen chloride and the peak shape when moisture is present in the sample gas.
【図８】 実施例において、試料ガス封じ切り後の所定
時間とピーク形状との関係を示す図である。FIG. 8 is a diagram showing a relationship between a predetermined time after the sample gas is sealed off and a peak shape in the example.
Ｉ…吸収強度、Ｐ…ピーク、Δλ…波長範囲、ν０…波
長、Δν…半値幅I: absorption intensity, P: peak, Δλ: wavelength range, ν 0 : wavelength, Δν: half width
───────────────────────────────────────────────────── フロントページの続き (72)発明者 矢野 良樹 東京都港区西新橋１−16−７ 日本酸素株 式会社内 Ｆターム(参考） 2G020 AA03 BA02 BA12 CA02 CB23 CB42 CC01 CD04 CD13 CD33 CD38 2G059 AA01 BB01 CC01 CC09 EE01 EE12 FF06 FF10 GG01 GG09 HH01 JJ01 MM01 MM04 MM14 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshiki Yano 1-16-7 Nishi-Shimbashi, Minato-ku, Tokyo F-term within Nippon Sanso Corporation 2G020 AA03 BA02 BA12 CA02 CB23 CB42 CC01 CD04 CD13 CD33 CD38 2G059 AA01 BB01 CC01 CC09 EE01 EE12 FF06 FF10 GG01 GG09 HH01 JJ01 MM01 MM04 MM14
Claims (4)
単一波長発振用半導体レーザー光源から発振されたレー
ザー光を用いて得られた吸収スペクトルに基づいて測定
することを特徴とするレーザ分光分析方法。The present invention is characterized in that concentration analysis of a plurality of components in a gas is measured based on an absorption spectrum obtained using laser light oscillated from a single semiconductor laser light source for single wavelength oscillation. Laser spectroscopy method.
を形成する成分を含んでいることを特徴とする請求項１
記載のレーザ分光分析方法。2. The method according to claim 1, wherein the plurality of components include at least a component forming a cluster.
The laser spectroscopic analysis method described in the above.
吸収スペクトルの半値半幅を基準とし、複数成分を計測
したときに得られた吸収スペクトルの半値半幅とその吸
収強度とから複数成分の濃度をそれぞれ換算補正するこ
とを特徴とする請求項１記載のレーザ分光分析方法。3. Based on a half width of an absorption spectrum obtained by measuring each of the plurality of components independently, a concentration of each of the plurality of components is determined from a half width of an absorption spectrum obtained when the plurality of components are measured and its absorption intensity. 2. The method according to claim 1, wherein conversion correction is performed.
長発振用レーザー光源を用いて試料ガス中の水分及び塩
化水素の濃度を分析することを特徴とする請求項１記載
のレーザ分光分析方法。4. The laser spectroscopic analysis method according to claim 1, wherein the concentration of water and hydrogen chloride in the sample gas is analyzed using a single single-wavelength laser light source having a wavelength of 1730 to 1760 nm.
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|---|---|---|---|
| JP2000325100A JP2002131228A (en) | 2000-10-25 | 2000-10-25 | Laser spectroscopic analysis method |
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| JPWO2006011487A1 (en) * | 2004-07-30 | 2008-05-01 | 国立大学法人 千葉大学 | Method for measuring glucose concentration in blood using infrared spectroscopy and apparatus using the same |
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