Analytical instrument, program for analytical instrument, and analytical method

Abstract

The present invention provides an analysis device 100 that employs light absorption to analyze a measurement target component contained in a sample, and that accurately measures a concentration of the measurement target component by reducing fluctuations in a modulation width of an oscillation wavelength of a laser light source resulting from ambient temperature variations, the analysis device 100 comprising: a laser light source 2 for emitting reference light onto the sample; an optical detector 5 for detecting the intensity of sample light, which is the reference light that has been transmitted through the sample; a temperature regulating unit 3 for regulating the temperature of the laser light source; a temperature sensor 4 for detecting the ambient temperature around the laser light source; a relationship data storage unit 73 for storing modulation correction relationship data representing a relationship between the ambient temperature around the laser light source 2 and a correction parameter for correcting a modulation width deviation relative to a default modulation width of the laser light source for measuring the measurement target component; and a control unit 7 for using the detected temperature from the temperature sensor 4 and the modulation correction relationship data to change a target temperature of the temperature regulating unit 3, or to change at least one of a drive voltage or a drive current that is applied for wavelength modulation of the laser light source 2.

Description

[Technical Field]

[0001] The present invention relates to analytical equipment, etc., used, for example, in the analysis of gas components. [Background technology]

[0002] Conventionally, as shown in Patent Document 1, there is an analytical method (TDLAS: Tunable Diode Laser Absorption Spectroscopy) that modulates the injection current of a semiconductor laser to sweep the oscillation wavelength and obtains the absorption spectrum of the gas to be measured in order to quantify its concentration.

[0003] In this case, if the target gas contains interfering components that have an interference effect, the absorption spectrum of the interfering component will overlap with the absorption peak position of the target gas, resulting in errors in concentration quantification. Therefore, in the above-mentioned TDLAS, the interference effect due to interfering components is corrected by performing spectral calculation processing such as spectral fitting, baseline estimation, or multivariate analysis on the absorption spectrum obtained by measurement.

[0004] However, semiconductor lasers have a problem in that the modulation (or sweep) range of their oscillation wavelength changes with changes in ambient temperature, which alters the acquired absorption spectrum and causes errors in concentration quantification results. Generally, semiconductor lasers are equipped with a function to control the temperature to a constant level using a Peltier element or the like, but even in such cases, changes in ambient temperature cause a discrepancy between the temperature sensor used for temperature control and the temperature of the semiconductor laser itself, resulting in a shift in the modulation range of the oscillation wavelength. This effect is particularly pronounced when using quantum cascade lasers, which consume relatively large amounts of power, as the light source. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-90521 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Therefore, the present invention has been made in view of the above-mentioned problems, and its main objective is to accurately measure the concentration of a target component in an analytical device that utilizes light absorption by reducing the change in the modulation range of the oscillation wavelength of the laser light source due to changes in ambient temperature. [Means for solving the problem]

[0007] In other words, the analytical apparatus according to the present invention is an analytical apparatus for analyzing a target component contained in a sample, and is characterized by comprising: a laser light source that irradiates the sample with reference light; a photodetector that detects the intensity of sample light transmitted through the sample by the reference light; a temperature control unit that adjusts the temperature of the laser light source; a temperature sensor that detects the ambient temperature of the laser light source; a relationship data storage unit that stores relationship data for modulation correction showing the relationship between the ambient temperature of the laser light source and correction parameters for correcting the deviation of the laser light source from a predetermined modulation range for measuring the target component; and a control unit that changes at least one of the target temperature of the temperature control unit or the drive voltage or drive current applied for wavelength modulation of the laser light source using the temperature detected by the temperature sensor and the relationship data for modulation correction. The modulation range of the oscillation wavelength of the laser light source refers to the modulation width of the oscillation wavelength of the laser light source. Furthermore, the correction parameters for correcting the deviation of the modulation width from the predetermined modulation range may include the amount of change in drive voltage (current) necessary to correct the deviation in modulation width.

[0008] In this configuration, modulation correction relationship data, which shows the relationship between the ambient temperature of the laser light source and correction parameters for correcting the deviation from a predetermined modulation range for measuring the target component, is used to change the target temperature of the temperature control unit or the drive voltage or drive current of the laser light source based on the temperature detected by the temperature sensor that detects the ambient temperature of the laser light source. As a result, changes in the absorption spectrum due to changes in the laser light source are reduced, and the concentration of the target component can be measured with high accuracy. The predetermined modulation range is the modulation range set for measuring the target component at a reference temperature, and is set before product shipment or set by the user.

[0009] Furthermore, the aforementioned laser light source has the problem that its oscillation wavelength changes with changes in ambient temperature, which alters the acquired absorption spectrum and causes errors in the concentration quantification results. To suitably solve this problem, it is desirable that the analytical apparatus of the present invention further comprises a wavelength shift determination unit that determines the amount of wavelength shift of the reference light from an intensity-related signal related to the intensity of the sample light, and a concentration calculation unit that calculates the concentration of the target component to be measured, corrected for the wavelength shift of the reference light, using the intensity-related signal related to the intensity of the sample light and the amount of wavelength shift.

[0010] Specifically, it is desirable that the wavelength shift determination unit determines the amount of wavelength shift by fitting reference data related to the optical absorption signals of the measurement target component and interference component, for which the amount of wavelength shift is known, with sample data related to the optical absorption signal obtained from the intensity of the sample light.

[0011] In laser absorption spectroscopy, the optical absorption spectrum of the target component is affected not only by interference (interference effect) due to components with overlapping absorption spectra, but also by changes in the concentration of coexisting components present at high concentrations (several percent to tens of percent), which alters its shape (coexistence effect). Specifically, the width of the optical absorption spectrum broadens, and the absorption peak becomes lower (broadening). As a result, measurement errors occur in the concentration of the target component. Furthermore, if the target component itself is present at a high concentration, it becomes a coexisting component, and changes in its own concentration cause coexistence effects (self-broadening). In other words, a coexisting component is a component that exerts a broadening effect on itself or other components.

[0012] As shown in Figure 12(A), the broadened optical absorption spectrum due to the influence of coexisting components shows a broadening of the spectral width and a decrease in the height of the absorption peaks depending on the concentration of the coexisting components, but the overall area remains almost unchanged. On the other hand, when the pressure fluctuates, as shown in Figure 12(B), the width of the optical absorption spectrum broadens, but the height of the absorption peaks remains almost unchanged.

[0013] Therefore, the inventors of this application focused on the differences and similarities between coexistence effects and changes in optical absorption spectra due to pressure fluctuations, and developed a broadening factor F that indicates the rate of change in the optical absorption spectrum of the target component caused by coexisting components contained in the sample. B By introducing a new method, if the absorbance signal at a certain pressure P is A(t,P), then the broadening factor F is due to the coexistence effect. B We found that the absorbance signal A'(t,P) when broadening occurs can be approximately expressed by the following equation.

[0014]

number

[0015] In other words, spectral changes due to coexistence effects are when the pressure is F B It doubles, and the absorbance becomes 1 / F BThis is almost the same as a doubled spectral change. The present invention utilizes this fact to convert broadening due to coexistence effects into pressure changes, and the basic concept is to perform coexistence effect correction simultaneously with pressure correction.

[0016] To reduce errors in concentration quantification results due to coexistence effects, it is desirable to have a broadening factor determination unit that determines a broadening factor indicating the rate of change in the optical absorption spectrum of the target component or interference component caused by coexistence components contained in the sample, and a concentration calculation unit that calculates the concentration of the target component corrected for coexistence effects by the coexistence components using an intensity-related signal related to the intensity of the sample light and the broadening factor. At this time, the width of the optical absorption spectrum also appears to change due to changes in the modulation width of the laser light source caused by changes in ambient temperature, making it difficult to distinguish from broadening due to coexistence effects. Therefore, by applying the modulation width correction of the laser light source of the present invention, changes in the modulation width of the laser light source due to changes in ambient temperature can be suppressed, and broadening due to coexistence effects can be correctly corrected, so that the concentration of the target component can be measured with even greater accuracy.

[0017] The parameter determination unit can determine the broadening factor by fitting reference data related to the optical absorption signals of the target component and interference component, for which the broadening factor or pressure is known, with sample data related to the optical absorption signal obtained from the intensity of the sample light. Here, fitting means comparing and matching the reference data and the sample data. When comparing and matching, the reference data is transformed and used using the relationship between the pressure value of the sample and the above-mentioned equation (Equation 1).

[0018] Furthermore, the parameter determination unit may determine the broadening factor using relational data showing the relationship between the concentration of the coexisting component and the broadening factor, and the measured concentration of the coexisting component.

[0019] One possible application of the analytical apparatus of the present invention is to measure the concentration of target components in combustion gases. In this case, the analytical apparatus of the present invention is intended to measure the concentration of at least one of the following in combustion gases: nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O), ammonia (NH3), ethane (C2H6), formaldehyde (HCHO), acetaldehyde (CH3CHO), sulfur dioxide (SO2), methane (CH4), methanol (CH3OH), or ethanol (C2H5OH). Examples of combustion gases include exhaust gases emitted from internal combustion engines, exhaust gases flowing through flues, and gases produced by burning samples. Furthermore, the analytical apparatus of the present invention uses a quantum cascade laser that emits laser light in the mid-infrared region, where these gases exhibit the strongest absorption, as a light source, and achieves a long optical path length by using a multiple reflection cell or a resonant cell, thereby enabling measurement of the above gases even at low concentrations of 100 ppm or less. Here, the long optical path length is 1 m to 100 m, preferably 1 m to 50 m, more preferably 5 m to 30 m, and even more preferably 5 m to 15 m.

[0020] The analytical apparatus of the present invention, when measuring the concentration of nitric oxide (NO) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of nitric oxide (NO) between 5.24 and 5.26 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 5.24 and 5.26 μm. Wavelengths between 5.24 and 5.26 μm, preferably between 5.245 and 5.247 μm, and more preferably at 5.2462 μm, contain one of the strongest absorption lines of nitric oxide (NO). In this wavelength range, the absorption intensities of interfering components in combustion gases, such as water (H2O), carbon dioxide (CO2), and / or ethylene (C2H4), are low, resulting in minimal interference. Consequently, the accuracy of nitric oxide (NO) concentration measurements can be improved.

[0021] The analytical apparatus of the present invention, when measuring the concentration of nitrogen dioxide (NO2) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of nitrogen dioxide (NO2) between 6.14 and 6.26 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 6.14 and 6.26 μm. Wavelengths between 6.14 and 6.26 μm, preferably between 6.145 and 6.254 μm, more preferably 6.2322 μm or 6.2538 μm, contain one of the strongest absorption lines of nitrogen dioxide (NO2). In this wavelength range, the absorption intensity of water (H2O) and / or ammonia (NH3), which are interfering components in combustion gases, is low, resulting in minimal interference. Consequently, the accuracy of nitrogen dioxide (NO2) concentration measurements can be improved.

[0022] The analytical apparatus of the present invention, when measuring the concentration of nitrous oxide (N2O) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of nitrous oxide (N2O) between 7.84 and 7.91 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 7.84 and 7.91 μm. Wavelengths between 7.84 and 7.91 μm, preferably between 7.845 and 7.907 μm, and more preferably 7.8455 μm, 7.8509 μm, 7.8784 μm, or 7.9067 μm, contain one of the strongest absorption lines for nitrous oxide (N2O), and the absorption intensities of interfering components in combustion gases in this wavelength range—water (H2O), methane (CH4), and / or acetylene (C2H2)—are low, resulting in minimal interference. As a result, the accuracy of measuring the concentration of nitrous oxide (N2O) can be improved.

[0023] The analytical apparatus of the present invention, when measuring the concentration of ammonia (NH3) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of ammonia (NH3) between 9.38 and 9.56 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 9.38 and 9.56 μm. Wavelengths between 9.38 and 9.56 μm, preferably between 9.384 and 9.557 μm, more preferably 9.3847 μm or 9.5566 μm, contain one of the strongest absorption lines for ammonia (NH3), and the absorption intensities of interfering components in combustion gases in this wavelength range—water (H2O), carbon dioxide (CO2), and / or ethylene (C2H4)—are low, resulting in minimal interference. As a result, the accuracy of ammonia (NH3) concentration measurements can be improved.

[0024] The analytical apparatus of the present invention, when measuring the concentration of ethane (C2H6) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of ethane (C2H6) between 3.33 and 3.36 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 3.33 and 3.36 μm. Wavelengths between 3.33 and 3.36 μm, preferably between 3.336 and 3.352 μm, and more preferably 3.3368 μm, 3.3482 μm, or 3.3519 μm, contain one of the strongest absorption lines of ethane (C2H6). In this wavelength range, the absorption intensities of interfering components in the combustion gas, such as water (H2O), methane (CH4), and / or ethylene (C2H4), are low, resulting in minimal interference. Consequently, the accuracy of measuring the concentration of ethane (C2H6) can be improved. Although the absorption intensity of ethane (C2H6) at a wavelength of 3.3406 μm is lower than that of the wavelengths of 3.3368 μm, 3.3482 μm, or 3.3519 μm mentioned above, there is an absorption line for water (H2O) near this wavelength, making it possible to simultaneously measure ethane (C2H6) and water (H2O).

[0025] The analytical apparatus of the present invention, when measuring the concentration of formaldehyde (HCHO) or acetaldehyde (CH3CHO) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of formaldehyde (HCHO) or acetaldehyde (CH3CHO) between 5.65 and 5.67 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 5.65 and 5.67 μm. Wavelengths between 5.65 and 5.67 μm, preferably between 5.651 and 5.652 μm, and more preferably at 5.6514 μm, contain one of the strongest absorption lines of formaldehyde (HCHO). In this wavelength range, the absorption intensity of water (H2O) and / or ammonia (NH3), which are interfering components in combustion gases, is low, resulting in minimal interference. As a result, the accuracy of formaldehyde (HCHO) concentration measurement can be improved. Furthermore, since this wavelength coincides with the strong absorption band of acetaldehyde (CH3CHO), it becomes possible to measure acetaldehyde (CH3CHO) or to measure formaldehyde (HCHO) and acetaldehyde (CH3CHO) simultaneously. Wavelengths between 5.65 and 5.67 μm, preferably between 5.665 and 5.667 μm, and more preferably at 5.6660 μm, show slightly lower absorption intensity for formaldehyde (HCHO) than the 5.6514 μm wavelength mentioned above, but lower absorption intensity for water (H2O), resulting in less interference between them. As a result, the accuracy of formaldehyde (HCHO) concentration measurement can be improved. Furthermore, since this wavelength coincides with the strong absorption band of acetaldehyde (CH3CHO), it becomes possible to measure acetaldehyde (CH3CHO) or to measure formaldehyde (HCHO) and acetaldehyde (CH3CHO) simultaneously.

[0026] The analytical apparatus of the present invention, when measuring the concentration of sulfur dioxide (SO2) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of sulfur dioxide (SO2) between 7.38 and 7.42 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 7.38 and 7.42 μm. Wavelengths between 7.38 and 7.42 μm, preferably between 7.385 and 7.417 μm, more preferably 7.3856 μm or 7.4163 μm, contain one of the strongest absorption lines of sulfur dioxide (SO2). In this wavelength range, the absorption intensities of interfering components in combustion gases, such as water (H2O), methane (CH4), acetylene (C2H2), and / or nitrous oxide (N2O), are low, resulting in minimal interference. Consequently, the accuracy of sulfur dioxide (SO2) concentration measurements can be improved.

[0027] The analytical apparatus of the present invention, when measuring the concentration of methane (CH4) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of methane (CH4) between 7.50 and 7.54 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 7.50 and 7.54 μm. Wavelengths between 7.50 and 7.54 μm, preferably between 7.503 and 7.504 μm, and more preferably at 7.5035 μm, contain one of the strongest absorption lines for methane (CH4). The absorption intensities of interfering components in combustion gases in this wavelength range—sulfur dioxide (SO2), acetylene (C2H2), and / or nitrous oxide (N2O)—are low, resulting in minimal interference. Consequently, the accuracy of methane (CH4) concentration measurements can be improved. Furthermore, water (H2O) absorption lines are present near this wavelength, enabling simultaneous measurement of methane (CH4) and water (H2O). Wavelengths between 7.50 and 7.54 μm, preferably between 7.535 and 7.536 μm, and more preferably at 7.5354 μm, have an absorption intensity of methane (CH4) that is approximately the same as that of the 7.5035 μm wavelength mentioned above. In this wavelength range, the absorption intensities of interfering components in the combustion gas, namely water (H2O), sulfur dioxide (SO2), acetylene (C2H2), and / or nitrous oxide (N2O), are lower, resulting in less interference. As a result, the accuracy of methane (CH4) concentration measurement can be improved.

[0028] The analytical apparatus of the present invention, when measuring the concentration of methanol (CH3OH) or ethanol (C2H5OH) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of methanol (CH3OH) or ethanol (C2H5OH) between 9.45 and 9.47 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 9.45 and 9.47 μm. Wavelengths between 9.45 and 9.47 μm, preferably between 9.467 and 9.468 μm, and more preferably at 9.4671 μm, contain one of the strongest absorption lines of methanol (CH3OH). The absorption intensities of interfering components in combustion gases in this wavelength range—ethylene (C2H4), ammonia (NH3), and / or carbon dioxide (CO2)—are low, resulting in minimal interference. Consequently, the accuracy of methanol (CH3OH) concentration measurements can be improved. Furthermore, since this wavelength coincides with the strong absorption band of ethanol (C2H5OH), it becomes possible to measure ethanol (C2H5OH) or to measure methanol (CH3OH) and ethanol (C2H5OH) simultaneously. Wavelengths between 9.45 and 9.47 μm, preferably between 9.455 and 9.456 μm, and more preferably at 9.4557 μm, have absorption intensities of methanol (CH3OH) or ethanol (C2H5OH) that are approximately the same as those at 9.4671 μm. In this wavelength range, the absorption intensities of interfering components in combustion gases, such as ethylene (C2H4), ammonia (NH3), and / or carbon dioxide (CO2), are lower, resulting in less interference. As a result, the accuracy of methanol (CH3OH) or ethanol (C2H5OH) concentration measurements can be improved. Furthermore, simultaneous measurement of methanol (CH3OH) and ethanol (C2H5OH) becomes possible.

[0029] Furthermore, one possible application of the analytical apparatus of the present invention is to measure the concentration of target components in process gases, including natural gas, used in chemical plants. In this case, the analytical apparatus of the present invention is intended to measure the concentration of at least one of the following in the process gas: carbon dioxide (CO2), carbon monoxide (CO), ethylene (C2H4), ethane (C2H6), water (H2O), acetylene (C2H2), methane (CH4), ammonia (NH3), and methanol (CH3OH). Furthermore, the analytical apparatus of the present invention uses a quantum cascade laser that emits laser light in the mid-infrared region, where these gases exhibit the strongest absorption, as a light source, and achieves a long optical path length by using a multiple reflection cell or a resonant cell, thereby enabling measurement of the above gases even at low concentrations of 100 ppm or less. Here, the long optical path length is 1 m to 100 m, preferably 1 m to 50 m, more preferably 5 m to 30 m, and even more preferably 5 m to 15 m.

[0030] The analytical apparatus of the present invention, when measuring the concentration of carbon dioxide (CO2) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of carbon dioxide (CO2) between 4.23 and 4.24 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 4.23 and 4.24 μm. Wavelengths between 4.23 and 4.24 μm, preferably between 4.234 and 4.238 μm, more preferably 4.2347 μm or 4.2371 μm, contain the strongest absorption lines of carbon dioxide (CO2). In this wavelength range, the absorption intensities of interfering components in process gases, such as methane (CH4), ethylene (C2H4), and / or ethane (C2H6), are low, resulting in minimal interference. Consequently, the accuracy of measuring low concentrations of carbon dioxide (CO2) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0031] Furthermore, when measuring the concentration of carbon dioxide (CO2) at a moderate concentration of 100 ppm to 1% using a multiple reflection cell or the like, the analytical apparatus of the present invention calculates the concentration based on the absorption of carbon dioxide (CO2) between 4.34 and 4.35 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 4.34 and 4.35 μm. Wavelengths between 4.34 and 4.35 μm, preferably between 4.342 and 4.347 μm, more preferably 4.3428 μm or 4.3469 μm, contain one of the moderately strong absorption lines of carbon dioxide (CO2). The absorption intensities of interfering components in process gases in this wavelength range, such as methane (CH4), ethylene (C2H4), and / or ethane (C2H6), are low, resulting in minimal interference. Consequently, the accuracy of measuring moderate concentrations of carbon dioxide (CO2) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0032] The analytical apparatus of the present invention, when measuring the concentration of low concentrations of carbon monoxide (CO) of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of carbon monoxide (CO) between 4.59 and 4.61 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 4.59 and 4.61 μm. Wavelengths between 4.59 and 4.61 μm, preferably between 4.594 and 4.604 μm, more preferably 4.5950 μm or 4.6024 μm, contain one of the strongest absorption lines of carbon monoxide (CO). In this wavelength range, the absorption intensities of interfering components in process gases, such as methane (CH4), ethylene (C2H4), and / or ethane (C2H6), are low, resulting in minimal interference. As a result, the accuracy of measuring low concentrations of carbon monoxide (CO) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved. It is also possible to simultaneously measure high concentrations of ethylene (C2H4) and ethane (C2H6).

[0033] The analytical apparatus of the present invention, when measuring the concentration of water (H2O) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of water (H2O) between 5.89 and 6.12 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 5.89 and 6.12 μm. Wavelengths between 5.89 and 6.12 μm, preferably between 5.896 and 5.934 μm, more preferably 5.8965 μm or 5.9353 μm, contain one of the strongest absorption lines for water (H2O). In this wavelength range, the absorption intensities of interfering components in process gases, such as methane (CH4), ethylene (C2H4), and / or ethane (C2H6), are low, resulting in minimal interference. Consequently, the accuracy of measuring low concentrations of water (H2O) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved. Wavelengths between 5.89 and 6.12 μm, preferably between 6.046 and 6.114 μm, more preferably 6.0486 μm or 6.1138 μm, contain one of the next strongest absorption lines for water (H2O) after the above wavelengths. The absorption intensities of interfering components in process gases in this wavelength range, such as methane (CH4), ethylene (C2H4), and / or ethane (C2H6), are low, resulting in minimal interference. Consequently, the accuracy of measuring the concentration of low-concentration water (H2O) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0034] The analytical apparatus of the present invention, when measuring the concentration of acetylene (C2H2) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of acetylene (C2H2) between 7.56 and 7.66 μm, or between 7.27 and 7.81 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 7.56 and 7.66 μm, or between 7.27 and 7.81 μm. Acetylene (C2H2) exhibits its strongest absorption line in the 3.0–3.1 μm wavelength range, but this wavelength range is difficult to achieve with quantum cascade lasers. However, the 3.0–3.1 μm wavelength range can be measured using interband cascade lasers (ICLs). On the other hand, wavelengths between 7.56–7.66 μm, preferably between 7.594–7.651 μm, are achievable with quantum cascade lasers, and exhibit the next strongest absorption line after the 3.0–3.1 μm wavelength range. More preferably, the strongest absorption line in this wavelength range exists at wavelengths of 7.5966 μm, 7.6233 μm, or 7.6501 μm. The absorption intensities of interfering components in the process gas, such as methane (CH4), ethylene (C2H4), and / or ethane (C2H6), are relatively small, resulting in minimal interference. As a result, the accuracy of measuring the concentration of low concentrations of acetylene (C2H2) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved. Wavelengths between 7.56 and 7.66 μm, preferably between 7.566 and 7.634 μm, and more preferably 7.5698 μm, 7.6231 μm, or 7.6367 μm, have lower absorption intensities than the wavelengths of 7.5966 μm, 7.6233 μm, or 7.6501 μm mentioned above. However, the absorption intensities of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) are lower, resulting in less interference between them. As a result, the accuracy of measuring low concentrations of acetylene (C2H2) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved. Furthermore, in order to simultaneously measure low concentrations of acetylene (C2H2) below 100 ppm and medium concentrations of methane (CH4) below 1000 ppm, the concentration is calculated based on the absorption of acetylene (C2H2) between 7.27 and 7.59 μm, or between 7.64 and 7.81 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 7.27 and 7.81 μm, between 7.27 and 7.59 μm, or between 7.64 and 7.81 μm. Here, it is desirable to calculate the concentration based on the absorption of acetylene between 7.378 and 7.638 μm, between 7.378 and 7.603 μm, or between 7.629 and 7.683 μm. More preferably, the concentration is calculated based on the absorption of acetylene at wavelengths of 7.5966 μm, 7.6501 μm, 7.5698 μm, and 7.6367 μm.

[0035] The analytical apparatus of the present invention, when measuring the concentration of methane (CH4) at a low concentration of 100 ppm or less using a multiple reflection cell or the like, calculates the concentration based on the absorption of methane (CH4) between 7.67 and 7.80 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 7.67 and 7.80 μm. Wavelengths between 7.67 and 7.80 μm, preferably between 7.670 and 7.792 μm, more preferably 7.6704 μm or 7.7914 μm, contain one of the strongest absorption lines of methane (CH4), and the absorption intensities of interfering components in process gases in this wavelength range are low, resulting in minimal interference. As a result, the accuracy of measuring low concentrations of methane (CH4) in process gases containing high concentrations of ethylene (C2H4) and / or ethane (C2H6) can be improved.

[0036] Furthermore, when measuring the concentration of methane (CH4) at a moderate concentration of 100 ppm to 1% using a multiple reflection cell or the like, the analytical apparatus of the present invention calculates the concentration based on the absorption of methane (CH4) between 8.10 and 8.14 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 8.10 and 8.14 μm. Wavelengths between 8.10 and 8.14 μm, preferably between 8.107 and 8.139 μm, more preferably 8.1073 μm or 8.1381 μm, contain one of the moderately strong absorption lines of methane (CH4), and the absorption intensities of interfering components in process gases in this wavelength range are low, resulting in minimal interference. As a result, the measurement accuracy of moderate concentrations of methane (CH4) in process gases containing high concentrations of ethylene (C2H4) and / or ethane (C2H6) can be improved.

[0037] Furthermore, when measuring the concentration of methane (CH4) at a high concentration of 1% or more using a multiple reflection cell or the like, the analytical apparatus of the present invention calculates the concentration based on the absorption of methane (CH4) between 8.10 and 8.13 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 8.10 and 8.13 μm. Wavelengths between 8.10 and 8.13 μm, preferably between 8.102 and 8.121 μm, more preferably 8.1022 μm or 8.1206 μm, contain one of the relatively weak absorption lines of methane (CH4). The absorption intensities of ethylene (C2H4) and / or ethane (C2H6), which are interfering components in process gases in this wavelength range, are low, resulting in minimal interference. As a result, the accuracy of measuring high concentrations of methane (CH4) in process gases containing high concentrations of ethylene (C2H4) and / or ethane (C2H6) can be improved.

[0038] The analytical apparatus of the present invention, when measuring the concentration of ethylene (C2H4) at a high concentration of 1% or more using a multiple reflection cell or the like, calculates the concentration based on the absorption of ethylene (C2H4) between 8.46 and 8.60 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 8.46 and 8.60 μm. Wavelengths between 8.46 and 8.60 μm, preferably between 8.464 and 8.599 μm, more preferably 8.4647 μm or 8.5981 μm, contain one of the relatively weak absorption lines of ethylene (C2H4). The absorption intensities of methane (CH4) and / or ethane (C2H6), which are interfering components in process gases in this wavelength range, are low, resulting in minimal interference. As a result, the accuracy of measuring high concentrations of ethylene (C2H4) in process gases containing high concentrations of methane (CH4) and / or ethane (C2H6) can be improved.

[0039] The analytical apparatus of the present invention, when measuring the concentration of ethane (C2H6) at a high concentration of 1% or more using a multiple reflection cell or the like, calculates the concentration based on the absorption of ethane (C2H6) between 6.13 and 6.14 μm, or between 6.09 and 6.45 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 6.13 and 6.14 μm, or between 6.09 and 6.45 μm. When measuring the concentration of ethane (C2H6) at a high concentration of 1% to 3%, it is desirable to calculate the concentration based on the absorption of ethane (C2H6) between 6.09 and 6.45 μm. Wavelengths between 6.13 and 6.14 μm, or between 6.09 and 6.45 μm, preferably between 6.135 and 6.139 μm, or between 6.463 and 6.619 μm, more preferably 6.1384 μm, 6.4673 μm, 6.5008 μm, 6.5624 μm, or 6.6145 μm, contain one of the relatively weak absorption lines of ethane (C2H6), and the absorption intensities of methane (CH4) and / or ethylene (C2H4), which are interfering components in process gases in this wavelength range, are low, resulting in minimal interference. As a result, the measurement accuracy of high concentrations of ethane (C2H6) in process gases containing high concentrations of methane (CH4) and / or ethylene (C2H4) can be improved.

[0040] The analytical apparatus of the present invention, when measuring the concentration of ammonia (NH3) at a medium concentration of 100 ppm to 200 ppm or a low concentration of 100 ppm or less, uses a multiple reflection cell or the like to calculate the concentration based on the absorption of ammonia (NH3) between 6.06 and 6.25 μm, or between 8.62 and 9.09 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 6.06 and 6.25 μm, or between 8.62 and 9.09 μm. Preferably, the concentration is calculated based on the absorption of ammonia between 6.141 and 6.153 μm, or between 8.939 and 8.968 μm, and more preferably, the concentration is calculated based on the absorption of ammonia at 6.1450 μm, 6.1487 μm, 6.1496 μm, 8.9604 μm, 8.9473 μm, or 8.7671 μm.

[0041] The analytical apparatus of the present invention, when measuring the concentration of methanol (CH3OH) at a high concentration of 1% or less using a multiple reflection cell or the like, calculates the concentration based on the methanol absorption between 9.35 and 9.62 μm. Here, the laser light source emits laser light with an oscillation wavelength that includes wavelengths between 9.35 and 9.62 μm. Preferably, the concentration is calculated based on the methanol absorption between 9.477 and 9.526 μm, and more preferably, the concentration is calculated based on the methanol absorption at 9.5168 μm, 9.5042 μm, or 9.4861 μm.

[0042] Furthermore, the program for an analytical apparatus according to the present invention is a program applied to an analytical apparatus that analyzes a target component contained in a sample, comprising a laser light source that irradiates a sample with reference light, a photodetector that detects sample light transmitted through the sample, a temperature control unit that adjusts the temperature of the laser light source, and a temperature sensor that detects the ambient temperature of the laser light source, and is characterized in that it causes the analytical apparatus to perform the following functions: a relationship data storage unit that stores relationship data for modulation correction that shows the relationship between the ambient temperature of the laser light source and correction parameters for correcting the deviation of the laser light source from a predetermined modulation range for measuring the target component; and a control unit that changes the target temperature of the temperature control unit or changes the drive voltage or drive current applied for wavelength modulation of the laser light source using the temperature detected by the temperature sensor and the modulation correction relationship data.

[0043] Furthermore, the analysis method according to the present invention is an analysis method for analyzing a target component contained in a sample using an analysis apparatus comprising a laser light source for irradiating a sample with reference light, a photodetector for detecting sample light transmitted through the sample, a temperature control unit for adjusting the temperature of the laser light source, and a temperature sensor for detecting the ambient temperature of the laser light source, characterized in that the target temperature of the temperature control unit is changed, or the drive voltage or drive current applied for wavelength modulation of the laser light source is changed, by referring to modulation correction relation data that shows the relationship between the ambient temperature of the laser light source and correction parameters for correcting the deviation of the laser light source from a predetermined modulation range for measuring the target component, using the modulation correction relation data. [Effects of the Invention]

[0044] According to the present invention described above, in an analytical device utilizing light absorption, the change in the modulation width of the oscillation wavelength of the laser light source due to changes in ambient temperature can be reduced, and the concentration of the target component can be measured with high accuracy. [Brief explanation of the drawing]

[0045] [Figure 1]This is a schematic diagram of the analytical apparatus according to one embodiment of the present invention. [Figure 2] This is a functional block diagram of the signal processing device in the same embodiment. [Figure 3] This figure shows the drive current (voltage) and modulation signal in a pseudo-continuous oscillation. [Figure 4] This is a schematic diagram illustrating the method for modulating the laser oscillation wavelength in the same embodiment. [Figure 5] This is a time-series graph showing an example of the oscillation wavelength, optical intensity I(t), logarithmic intensity L(t), characteristic signal Fi(t), and correlation value Si(t) in the same embodiment. [Figure 6] This figure shows the wavelength shift and modulation width shift in intensity-related signals (absorption signals). [Figure 7] This graph shows (a) related data for wavelength correction and (b) related data for modulation correction in the same embodiment. [Figure 8] This is a lookup table showing (a) related data for wavelength correction and (b) related data for modulation correction in the same embodiment. [Figure 9] This figure shows a conceptual diagram of concentration calculation using the standalone correlation value and the measured correlation value in the same embodiment. [Figure 10] This is a functional block diagram of the signal processing device in a modified embodiment. [Figure 11] This is a schematic diagram of the entire analytical apparatus according to a modified embodiment. [Figure 12] This is a schematic diagram showing spectral changes due to coexistence effects and spectral changes due to pressure changes. [Modes for carrying out the invention]

[0046] The analyzer 100 of this embodiment is a concentration measuring device that measures the concentration of a target component contained in a sample gas such as combustion gas or combustion exhaust gas, or process gas. As shown in Figure 1, it comprises a cell 1 into which the sample gas is introduced, a semiconductor laser 2 which is a laser light source that irradiates cell 1 with modulated laser light, a temperature control unit 3 that adjusts the temperature of the semiconductor laser 2, a temperature sensor 4 that detects the ambient temperature of the semiconductor laser 2, a photodetector 5 which is provided on the optical path of the sample light, which is the laser light that has passed through cell 1, and receives the sample light, and a signal processing device 6 which receives the output signal of the photodetector 5 and calculates the concentration of the target component based on its value. Here, combustion gas refers to gas being burned in an internal combustion engine, external combustion engine, industrial furnace, incinerator, turbine, or power plant such as in an automobile, and combustion exhaust gas refers to gas after combustion discharged from an internal combustion engine, external combustion engine, industrial furnace, incinerator, turbine, or power plant such as in an automobile. Furthermore, process gas refers to gases used in chemical plants such as petrochemicals, coal chemicals, natural gas chemicals, petroleum refining, methanation, and gasifiers, and includes not only raw material gases such as natural gas, but also gases separated in chemical plants or gases produced in chemical plants.

[0047] In this embodiment, the analyzer 100 is connected to an introduction channel for introducing a sampling gas, and to an exhaust channel for discharging the gas analyzed by the analyzer 100. A pump for introducing the sampling gas into the analyzer 100 is provided in either the introduction channel or the exhaust channel. The introduction channel may be configured to directly sample exhaust gas from an exhaust pipe or the like, or to introduce exhaust gas from a bag in which exhaust gas has been collected, or to introduce exhaust gas diluted by a dilution device such as a CVS (Constant Volume Sampler).

[0048] Let's explain each part. Cell 1 is made of a transparent material such as quartz, calcium fluoride, or barium fluoride, which absorbs very little light in the absorption wavelength band of the component to be measured, and has an inlet port and an outlet port for light. Although not shown in the figure, Cell 1 is provided with an inlet port for introducing gas into the interior and an outlet port for discharging the gas from the interior, and the sample gas is introduced into Cell 1 through this inlet port.

[0049] Semiconductor laser 2, in this context, is a quantum cascade laser (QCL), a type of semiconductor laser 2, which emits mid-infrared (4-12 μm) laser light. This semiconductor laser 2 can modulate (change) its oscillation wavelength by a given current (or voltage). Note that other types of lasers may be used as long as the oscillation wavelength is variable, and the oscillation wavelength may be changed by changing the temperature, etc.

[0050] The temperature control unit 3 adjusts the temperature of the semiconductor laser 2 and uses a thermoelectric conversion element such as a Peltier element. In this embodiment, the temperature control unit 3 has the semiconductor laser 2 and a temperature sensor (not shown) for detecting the temperature of the semiconductor laser 2 mounted on its upper heat-absorbing surface, and a heat sink (not shown), such as a heat sink fin, is provided on its lower heat-dissipating surface. The temperature control unit 3 adjusts the temperature of the semiconductor laser 2 by controlling the applied DC voltage (DC current) according to a target temperature set by the temperature control unit 72, which will be described later.

[0051] The temperature sensor 4 detects the ambient temperature around the semiconductor laser 2. In this case, it detects the temperature of the atmosphere inside the package housing the semiconductor laser and the temperature control unit 3, or the ambient temperature in the vicinity outside the package.

[0052] In this example, the photodetector 5 is a relatively inexpensive thermal type such as a thermopile, but other types, such as quantum photoelectric elements with good responsiveness, like HgCdTe, InGaAs, InAsSb, or PbSe, may also be used.

[0053] The signal processing device 6 comprises an analog electrical circuit consisting of a buffer, an amplifier, etc., a digital electrical circuit consisting of a CPU, memory, etc., and at least one of the following to mediate between the analog and digital electrical circuits: an AD converter, a DA converter, etc. According to a predetermined program stored in a predetermined area of ​​the memory, the CPU and its peripheral devices cooperate to perform functions as a control unit 7 that controls the semiconductor laser 2 and the temperature control unit 3, as shown in Figure 2, and as a signal processing unit 8 that receives the output signal from the photodetector 5, processes its value, and calculates the concentration of the component to be measured.

[0054] The following details each part. The control unit 7 includes a light source control unit 71 that controls the oscillation and modulation width of the semiconductor laser 2, and a temperature control control unit 72 that controls the temperature control unit 3 to a predetermined temperature.

[0055] The light source control unit 71 controls the current source (or voltage source) that drives the semiconductor laser 2 by outputting a current (or voltage) control signal. Specifically, as shown in Figure 3, the light source control unit 71 changes a drive current (or drive voltage) that provides wavelength modulation at a predetermined frequency, separate from the drive current (or drive voltage) that causes the semiconductor laser 2 to pulse, thereby modulating the oscillation wavelength of the laser light output from the semiconductor laser 2 at a predetermined frequency with respect to the center wavelength. As a result, the semiconductor laser 2 emits modulated light modulated at a predetermined modulation frequency.

[0056] In this embodiment, the light source control unit 71 changes the drive current in a triangular wave shape and modulates the oscillation wavelength in a triangular wave shape (see "Oscillation Wavelength" in Figure 5). In practice, the modulation of the drive current is performed using a different function so that the oscillation wavelength becomes triangular wave. Furthermore, as shown in Figure 4, the oscillation wavelength of the laser light is modulated with the peak of the optical absorption spectrum of the component to be measured as the center wavelength. In addition, the light source control unit 71 may change the drive current in a sinusoidal wave shape, a sawtooth wave shape, or an arbitrary function shape and modulate the oscillation wavelength in a sinusoidal wave shape, a sawtooth wave shape, or an arbitrary function shape.

[0057] Specifically, when the analyzer 100 measures the concentration of at least one of the following in combustion gases: nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O), ammonia (NH3), ethane (C2H6), formaldehyde (HCHO), acetaldehyde (CH3CHO), sulfur dioxide (SO2), methane (CH4), methanol (CH3OH), or ethanol (C2H5OH), the light source control unit 71 modulates the semiconductor laser 2 to fall within the following wavelength modulation range. The semiconductor laser 2 is appropriately selected to emit modulated light modulated within the following wavelength modulation range.

[0058] When the component to be measured is nitric oxide (NO) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 5.24 and 5.26 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 5.245 and 5.247 μm, and more preferably wavelengths between 5.2462 μm. By modulating in this way, the interference effects of water (H2O), carbon dioxide (CO2), and / or ethylene (C2H4) can be reduced, and the measurement accuracy of low concentrations of nitric oxide (NO) can be improved.

[0059] When the component to be measured is nitrogen dioxide (NO2) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 6.14 and 6.26 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 6.145 and 6.254 μm, more preferably 6.2322 μm or 6.2538 μm. By modulating in this way, the interference effect of water (H2O) and / or ammonia (NH3) can be reduced, and the measurement accuracy of low concentrations of nitrogen dioxide (NO2) can be improved.

[0060] When the component to be measured is nitrous oxide (N2O) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 7.84 and 7.91 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 7.845 and 7.907 μm, more preferably 7.8455 μm, 7.8509 μm, 7.8784 μm, or 7.9067 μm. By modulating in this way, the interference effects of water (H2O), methane (CH4), and / or acetylene (C2H2) can be reduced, and the measurement accuracy of low concentrations of nitrous oxide (N2O) can be improved.

[0061] When the component to be measured is ammonia (NH3) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 9.38 and 9.56 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 9.384 and 9.557 μm, more preferably 9.3847 μm or 9.5566 μm. By modulating in this way, the interference effects of water (H2O), carbon dioxide (CO2), and / or ethylene (C2H4) can be reduced, and the measurement accuracy of low-concentration ammonia (NH3) can be improved.

[0062] When the component to be measured is ethane (C2H6) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 3.33 and 3.36 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 3.336 and 3.352 μm, more preferably wavelengths of 3.3368 μm, 3.3482 μm, or 3.3519 μm. By modulating in this way, the interference effects of water (H2O), methane (CH4), and / or ethylene (C2H4) can be reduced, and the measurement accuracy of low-concentration ethane (C2H6) can be improved.

[0063] When the component to be measured is formaldehyde (HCHO) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 5.65 and 5.67 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 5.651 and 5.652 μm, more preferably including a wavelength of 5.6514 μm. By modulating in this way, the interference effects of water (H2O) and / or ammonia (NH3) can be reduced, and the measurement accuracy of low-concentration formaldehyde (HCHO) can be improved. Furthermore, since these wavelengths coincide with the strong absorption band of acetaldehyde (CH3CHO), simultaneous measurement of formaldehyde (HCHO) and acetaldehyde (CH3CHO) becomes possible.

[0064] Furthermore, the light source control unit 71 can also modulate the wavelength modulation range of the laser light to preferably include wavelengths between 5.665 and 5.667 μm, more preferably including a wavelength of 5.6660 μm. Although the absorption intensity of formaldehyde (HCHO) is slightly lower than that of the 5.6514 μm wavelength mentioned above, the absorption intensity of water (H2O) is even lower, resulting in less interference between them. As a result, the measurement accuracy of formaldehyde (HCHO) concentration can be improved. In addition, since this wavelength coincides with the strong absorption band of acetaldehyde (CH3CHO), it becomes possible to measure acetaldehyde (CH3CHO), or to measure formaldehyde (HCHO) and acetaldehyde (CH3CHO) simultaneously.

[0065] When the component to be measured is sulfur dioxide (SO2) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 7.38 and 7.42 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 7.385 and 7.417 μm, more preferably 7.3856 μm or 7.4163 μm. By modulating in this way, the interference effects of water (H2O), methane (CH4), acetylene (C2H2), and / or nitrous oxide (N2O) can be reduced, and the measurement accuracy of low concentrations of sulfur dioxide (SO2) can be improved.

[0066] When the component to be measured is methane (CH4) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 7.50 and 7.54 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 7.503 and 7.504 μm, and more preferably 7.5035 μm. By modulating in this way, the interference effects of water (H2O), sulfur dioxide (SO2), acetylene (C2H2), and / or nitrous oxide (N2O) can be reduced, and the measurement accuracy of low-concentration methane (CH4) can be improved. Furthermore, by modulating to include 7.5035 μm, there is an absorption line for water (H2O) near this wavelength, making simultaneous measurement of methane (CH4) and water (H2O) possible.

[0067] Furthermore, the light source control unit 71 can also modulate the wavelength modulation range of the laser light to preferably include wavelengths between 7.535 and 7.536 μm, more preferably including a wavelength of 7.5354 μm. The absorption intensity of methane (CH4) is approximately the same as that of the 7.5035 μm wavelength mentioned above, and the absorption intensities of interfering components in the combustion gas in this wavelength range, such as water (H2O), sulfur dioxide (SO2), acetylene (C2H2), and / or nitrous oxide (N2O), are smaller, resulting in less interference. As a result, the measurement accuracy of the methane (CH4) concentration can be improved.

[0068] When the component to be measured is methanol (CH3OH) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 9.45 and 9.47 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 9.467 and 9.468 μm, and more preferably wavelengths between 9.4671 μm. By modulating in this way, the interference effects of ethylene (C2H4), ammonia (NH3), and / or carbon dioxide (CO2) can be reduced, and the measurement accuracy of low-concentration methanol (CH3OH) can be improved. Furthermore, since these wavelengths coincide with the strong absorption band of ethanol (C2H5OH), simultaneous measurement of methanol (CH3OH) and ethanol (C2H5OH) becomes possible.

[0069] Furthermore, the light source control unit 71 can also modulate the wavelength modulation range of the laser light so that it preferably includes wavelengths between 9.455 and 9.456 μm, and more preferably wavelengths including 9.4557 μm. The absorption intensity of methanol (CH3OH) or ethanol (C2H5OH) is approximately the same as that of 9.4671 μm, but the absorption intensities of ethylene (C2H4), ammonia (NH3), and / or carbon dioxide (CO2), which are interfering components in the combustion gas in this wavelength range, are smaller, resulting in less interference. As a result, the measurement accuracy of the methanol (CH3OH) or ethanol (C2H5OH) concentration can be improved. In addition, simultaneous measurement of methanol (CH3OH) and ethanol (C2H5OH) becomes possible.

[0070] Furthermore, when the analyzer 100 measures the concentration of at least one of the following in the process gas: carbon dioxide (CO2), carbon monoxide (CO), ethylene (C2H4), ammonia (NH3), ethane (C2H6), water (H2O), acetylene (C2H2), methane (CH4), ammonia (NH3), and methanol (CH3OH), the light source control unit 71 modulates the semiconductor laser 2 to fall within the following wavelength modulation range.

[0071] When the component to be measured is low-concentration carbon dioxide (CO2) at 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 4.23 and 4.24 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 4.234 and 4.238 μm, or between 4.235 and 4.238 μm, more preferably 4.2347 μm, or 4.2371 μm. By modulating in this way, the interference effects of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be reduced, and the measurement accuracy of low-concentration carbon dioxide (CO2) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0072] When the component to be measured is carbon dioxide (CO2) at a moderate concentration of 100 ppm to 1%, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 4.34 and 4.35 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 4.342 and 4.347 μm, more preferably 4.3428 μm or 4.3469 μm. By modulating in this way, the interference effects of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be reduced, and the measurement accuracy of the concentration of moderate carbon dioxide (CO2) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0073] When the component to be measured is low-concentration carbon monoxide (CO) of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 4.59 and 4.61 μm, or between 4.59 and 4.60 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 4.594 and 4.604 μm, more preferably 4.5950 μm, or 4.6024 μm. By modulating in this way, the interference effects of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be reduced, and the measurement accuracy of low-concentration carbon monoxide (CO) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0074] When the component to be measured is water (H2O) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 5.89 and 6.12 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 5.896 and 5.934 μm, more preferably 5.8965 μm or 5.9353 μm. By modulating in this way, the interference effects of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be reduced, and the measurement accuracy of the concentration of low-concentration water (H2O) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0075] Furthermore, the light source control unit 71 can also modulate the wavelength modulation range of the laser light so that it preferably includes wavelengths between 6.046 and 6.114 μm, more preferably 6.0486 μm or 6.1138 μm. By modulating in this way, the interference effects of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be reduced, and the measurement accuracy of low concentrations of water (H2O) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0076] When the component to be measured is acetylene (C2H2) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 7.56 and 7.66 μm, between 7.27 and 7.81 μm, between 7.27 and 7.24 μm, or between 7.25 and 7.81 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light so that it preferably includes wavelengths between 7.378 and 7.638 μm, 7.378 and 7.603 μm, 7.378 and 7.420 μm, 7.430 and 7.603 μm, 7.430 and 7.638 μm, 7.629 and 7.683 μm, or 7.594 and 7.651 μm, more preferably including wavelengths of 7.5966 μm, 7.6233 μm, or 7.6501 μm. By modulating the signal in this way, interference from methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be reduced, improving the accuracy of measuring the concentration of low concentrations of acetylene (C2H2) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6).

[0077] Furthermore, the light source control unit 71 can also modulate the wavelength modulation range of the laser light so that it preferably includes wavelengths between 7.566 and 7.634 μm, and more preferably wavelengths of 7.5698 μm, 7.6231 μm, or 7.6367 μm. By modulating in this way, the interference effects of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be reduced, and the measurement accuracy of low concentrations of acetylene (C2H2) in process gases containing high concentrations of methane (CH4), ethylene (C2H4), and / or ethane (C2H6) can be improved.

[0078] When the component to be measured is methane (CH4) at a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 7.67 and 7.80 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 7.670 and 7.792 μm, more preferably 7.6704 μm or 7.7914 μm. By modulating in this way, the interference effect of ethylene (C2H4) and / or ethane (C2H6) can be reduced, and the measurement accuracy of low concentrations of methane (CH4) in process gases containing high concentrations of ethylene (C2H4) and / or ethane (C2H6) can be improved.

[0079] When the component to be measured is methane (CH4) at a moderate concentration of 100 ppm to 1%, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 8.10 and 8.14 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 8.107 and 8.139 μm, more preferably 8.1073 μm or 8.1381 μm. By modulating in this way, the interference effect of ethylene (C2H4) and / or ethane (C2H6) can be reduced, and the measurement accuracy of the concentration of moderate methane (CH4) in process gas containing high concentrations of ethylene (C2H4) and / or ethane (C2H6) can be improved.

[0080] When the component to be measured is methane (CH4) at a high concentration of 1% or more, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 8.10 and 8.13 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 8.102 and 8.121 μm, more preferably 8.1022 μm or 8.1206 μm. By modulating in this way, the interference effect of ethylene (C2H4) and / or ethane (C2H6) can be reduced, and the measurement accuracy of the high concentration of methane (CH4) in process gas containing high concentrations of ethylene (C2H4) and / or ethane (C2H6) can be improved.

[0081] When the component to be measured is methane (CH4) at a high concentration of 1% or more, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 8.10 and 8.13 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths of 8.1022 μm or 8.1206 μm. By modulating in this way, the interference effect of ethylene (C2H4) and / or ethane (C2H6) can be reduced, and the measurement accuracy of the high concentration of methane (CH4) in process gas containing high concentrations of ethylene (C2H4) and / or ethane (C2H6) can be improved.

[0082] When the component to be measured is ethylene (C2H4) at a high concentration of 1% or more, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 8.46 and 8.60 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 8.464 and 8.599 μm, more preferably 8.4647 μm or 8.5981 μm. By modulating in this way, the interference effect of methane (CH4) and / or ethane (C2H6) can be reduced, and the measurement accuracy of the high concentration of ethylene (C2H4) in process gas containing high concentrations of methane (CH4) and / or ethane (C2H6) can be improved.

[0083] When the component to be measured is ethane (C2H6) at a high concentration of 1% or more, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 6.13 and 6.14 μm, between 6.09 and 6.45 μm, between 6.09 and 6.39 μm, or between 6.41 μm and 6.45 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 6.135 and 6.139 μm, or between 6.463 and 6.619 μm, and more preferably include wavelengths of 6.1384 μm, 6.4673 μm, 6.5008 μm, 6.5624 μm, or 6.6145 μm. By modulating the system in this way, the interference effects of methane (CH4) and / or ethylene (C2H4) can be reduced, thereby improving the accuracy of measuring the concentration of high-concentration ethane (C2H6) in process gases containing high concentrations of methane (CH4) and / or ethylene (C2H4).

[0084] When the component to be measured is ammonia (NH3) at a medium concentration of 100 ppm to 200 ppm or a low concentration of 100 ppm or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 6.06 and 6.25 μm, 6.06 and 6.14 μm, 6.15 and 6.17 μm, 6.19 and 6.25 μm, or 8.62 and 9.09 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light so that it preferably includes wavelengths between 6.141 and 6.153 μm, 6.141 and 6.149 μm, 6.150 and 6.153 μm, or 8.939 and 8.968 μm, more preferably including wavelengths of 6.1450 μm, 6.1487 μm, 6.1496 μm, 8.9604 μm, 8.9473 μm, or 8.7671 μm. By modulating in this way, the interference effect of methane (CH4) and / or ethylene (C2H4) can be reduced, and the measurement accuracy of medium or low concentrations of ammonia (NH3) in process gases containing high concentrations of methane (CH4) and / or ethylene (C2H4) can be improved.

[0085] When the target component is methanol (CH3OH) at a high concentration of 1% or less, the light source control unit 71 modulates the wavelength modulation range of the laser light to include wavelengths between 9.35 and 9.62 μm. Specifically, the light source control unit 71 modulates the wavelength modulation range of the laser light to preferably include wavelengths between 9.477 and 9.526 μm, more preferably including wavelengths of 9.5168 μm, 9.5042 μm, or 9.4861 μm. By modulating in this way, the interference effects of ethylene (C2H4), ammonia (NH3), and / or carbon dioxide (CO2) can be reduced, and the measurement accuracy of low-concentration methanol (CH3OH) can be improved. Note that when measuring methanol, the inside of cell 1 needs to be reduced to 15 kPa or less.

[0086] The temperature control unit 72 controls the current source (or voltage source) of the temperature control unit 3 by outputting a control signal to set the temperature control unit 3 to a predetermined target temperature. As a result, the temperature control unit 3 adjusts the semiconductor laser 2 to the predetermined target temperature.

[0087] Furthermore, the control unit 7 of this embodiment includes a relational data storage unit 73 that stores wavelength correction relational data showing the relationship between the ambient temperature of the semiconductor laser 2 and a correction parameter P(Δλ) (see Figure 6) for correcting the wavelength shift with respect to the target wavelength for measuring the component to be measured by the semiconductor laser 2, and modulation correction relational data showing the relationship between the ambient temperature and a correction parameter P(Δw) (see Figure 6) for correcting the modulation width shift of the semiconductor laser 2.

[0088] Here, the wavelength correction data is shown in Figure 7(a), and is generated by first experimentally or by calculation determining the target temperature change, which is the parameter P(Δλ) necessary to correct the wavelength shift of the semiconductor laser 2 for each ambient temperature of the semiconductor laser 2. In Figure 7(a), P(Δλ) is the target temperature change, T0 is the reference temperature (for example, room temperature (25℃)), and t kThis is a coefficient that indicates the degree of influence of the target temperature change at ambient temperature T on the reference temperature T0. The wavelength correction data may be in the form of an equation, as shown in Figure 7(a), or in the form of a lookup table, as shown in Figure 8(a).

[0089] Furthermore, the modulation correction data is shown in Figure 7(b), and is generated by pre-determining, experimentally or by calculation, the change in the drive voltage (current), which is the parameter P(Δw) necessary to correct the modulation width shift of the semiconductor laser 2 for each ambient temperature of the semiconductor laser 2. In Figure 7(b), P(Δw) is the change in drive voltage (current), T0 is the reference temperature (e.g., room temperature (25°C)), and v k This coefficient indicates the degree of influence of the change in drive voltage (current) at ambient temperature T relative to the reference temperature T0. The modulation correction data may be in formula form as shown in Figure 7(b) or in lookup table form as shown in Figure 8(b).

[0090] Furthermore, the temperature control unit 72 corrects the wavelength shift of the semiconductor laser 2 by changing the target temperature of the temperature control unit 3 using the detected temperature and wavelength correction data obtained from the temperature sensor 4. The light source control unit 71 also corrects the modulation width of the semiconductor laser 2 by changing the drive voltage or drive current of the semiconductor laser 2 using the detected temperature and modulation correction data obtained from the temperature sensor 4. Specifically, the light source control unit 71 corrects the modulation width by adjusting the amplitude or offset of the modulation voltage (modulation current) used to modulate the wavelength.

[0091] The signal processing unit 8 consists of a logarithmic calculation unit 81, a correlation value calculation unit 82, a storage unit 83, a wavelength shift determination unit 84, a concentration calculation unit 85, and the like.

[0092] The logarithmic calculation unit 81 applies logarithmic calculations to the light intensity signal, which is the output signal of the photodetector 5. The function I(t) that shows the time change of the light intensity signal obtained by the photodetector 5 is as shown in "Light Intensity I(t)" in Figure 5, and by applying logarithmic calculations, it becomes as shown in "Logarithmic Intensity L(t)" in Figure 5.

[0093] The correlation value calculation unit 82 calculates the correlation value between the intensity-related signal related to the intensity of the sample light and each of a plurality of predetermined characteristic signals. The characteristic signal is a signal for extracting the waveform characteristics of the intensity-related signal by taking the correlation with the intensity-related signal. As the characteristic signal, for example, a sine wave signal or various signals adapted to the waveform characteristics to be extracted from other intensity-related signals can be used.

[0094] Hereinafter, an example in the case of using a signal other than the sine wave signal as the characteristic signal will be described. The correlation value calculation unit 82 calculates the correlation value between the intensity-related signal related to the intensity of the sample light and each of a plurality of characteristic signals that obtain a different correlation from the sine wave signal (sine function) with respect to the intensity-related signal. Here, the correlation value calculation unit 82 uses the logarithmically operated optical intensity signal (logarithmic intensity L(t)) as the intensity-related signal.

[0095] Also, the correlation value calculation unit 82 uses a number of characteristic signals F i (t) (i = 1, 2, ···, n) equal to or more than the sum of the number of types of the measurement target components and the number of types of interference components to be removed, and according to the following formula (Equation 1), a plurality of sample correlation values S i which are the correlation values between the intensity-related signal of the sample light and each of the plurality of characteristic signals are calculated. Note that T in the following formula (Equation 1) is the modulation period.

[0096]

Equation

[0097] When calculating the sample correlation value, the correlation value calculation unit 82 subtracts the reference correlation value R i which is the correlation value between the intensity-related signal L(t) of the sample light and the plurality of characteristic signals F i from the correlation value S i which is the correlation value between the intensity-related signal L0(t) of the reference light and the plurality of characteristic signals F i to correct the sample correlation value S′ iIt is desirable to calculate this. This removes the offset included in the sample correlation value, resulting in a correlation value proportional to the concentration of the target component and the interfering component, thereby reducing measurement errors. Alternatively, a configuration that does not subtract the reference correlation value is also acceptable.

[0098] Here, the timing of acquiring the reference light can be simultaneous with the sample light, before or after the measurement, or at any arbitrary timing. The intensity-related signal or reference correlation value of the reference light may be acquired in advance and stored in the storage unit 83. Another method for simultaneously acquiring the reference light is to provide two photodetectors 5 and split the modulated light from the semiconductor laser 2 using a beam splitter or the like, using one for sample light measurement and the other for reference light measurement.

[0099] In this embodiment, the correlation value calculation unit 82 calculates multiple feature signals F iFor (t), a function is used that is better suited to capturing the waveform characteristics of the logarithmic intensity L(t) than a sine function. When a sample gas containing the target component and one interference component needs to be further corrected for the effect of the reference light's wavelength shift, it is conceivable to use three feature signals F1(t), F2(t), and F3(t). These three feature signals could, for example, be a function based on a Lorentz function that closely resembles the shape of the absorption spectrum shown in equation (3) below, and a partial derivative of the shift of the Lorentz function-based function from the reference time position. In equation (3), w is the Lorentz width, s is the shift of the absorption peak from the reference time position due to the wavelength shift, A is an arbitrary constant, and A1, A2, and A3 are offsets adjusted so that when F1(t), F2(t), and F3(t) are integrated over the modulation period, they become zero, respectively. Using such functions as feature signals allows for more sensitive capture of spectral changes due to the reference light's wavelength shift, and enables more accurate correction of the reference light's wavelength shift effect. Furthermore, instead of using a function based on the Lorentz function as the feature signal, a function based on the Voigt function or a function based on the Gaussian function can also be used. By using such a function as the feature signal, a larger correlation value can be obtained than when using a sine function, thereby improving measurement accuracy.

[0100]

number

[0101] The storage unit 83 stores the intensity-related signals of the measured component and each interference component when they exist individually in the wavelength shift amount of a known reference light, and a plurality of feature signals F i This stores the single correlation values, which are the correlation values ​​per unit concentration of the measured component and each interfering component, obtained from (t). Multiple feature signals F are used to determine these single correlation values. i (t) is a set of feature signals F used in the correlation value calculation unit 82. i This is the same as (t). In this way, the storage unit 83 stores individual correlation values ​​for each wavelength shift of various reference lights.

[0102] Here, when the storage unit 83 stores the individual correlation value, it is desirable to store a corrected individual correlation value that is obtained by subtracting the reference correlation value from the correlation value when the target component and each interfering component exist individually, and then converting it to a value per unit concentration. This removes the offset included in the individual correlation value, resulting in a correlation value proportional to the concentration of the target component and the interfering component, thereby reducing measurement errors. However, a configuration in which the reference correlation value is not subtracted is also acceptable.

[0103] The wavelength shift determination unit 84 determines the wavelength shift amount W of the reference light from the light intensity signal, which is the output signal of the photodetector 5.

[0104] One possible method for determining the wavelength shift W is the following procedure.

[0105] (a) Wavelength shift W of each reference light k The characteristic signals F of the measured component and the interference component in (k=1,2,···,l) i Each individual correlation value s corresponding to (t) itar (W k ), s iint (W k The wavelength shift W of the reference light is determined by first obtaining the sample correlation value obtained during measurement and comparing and matching it with the single correlation value. Specific comparison and matching methods include, for example, the steepest descent method, the Gauss-Newton method, and the Levenberg-Marquardt method, which involve iterative calculations using nonlinear least squares methods. In this method, the number of required feature signals is greater than or equal to the sum of the number of types of components to be measured and the number of types of interference components plus 1. The reason for adding 1 is to correspond to the wavelength shift amount, which is a parameter common to the optical absorption spectra of each component.

[0106] (b) The wavelength shift W of the reference light is determined using relational data showing the relationship between ambient temperature and wavelength shift W, and the measured ambient temperature. In this case, the relational data is generated in advance by experimentally or computationally determining the wavelength shift W of the reference light for each ambient temperature of the light source 2.

[0107] The concentration calculation unit 85 calculates the concentration of the target component using multiple sample correlation values ​​obtained by the correlation value calculation unit 82.

[0108] Specifically, the concentration calculation unit 85 calculates the concentration of the target component based on multiple sample correlation values ​​obtained by the correlation value calculation unit 82, the wavelength shift amount W determined by the wavelength shift determination unit 84, and multiple individual correlation values ​​stored in the storage unit 83. More specifically, the concentration calculation unit 85 corrects and obtains the multiple individual correlation values ​​stored in the storage unit 83 from the wavelength shift amount W obtained by the wavelength shift determination unit 84. Then, the concentration calculation unit 85 calculates the concentration of the target component by solving a system of equations consisting of multiple sample correlation values ​​obtained by the correlation value calculation unit 82, the corrected multiple individual correlation values ​​corresponding to the determined wavelength shift amount W, and the concentrations of the target component and each interference component (see Figure 9).

[0109] Next, an example of the operation of this analytical device 100 will be described, along with a detailed explanation of each of the aforementioned parts. In the following, we assume that the sample gas contains one target component and one interfering component.

[0110] <Reference Measurement> With the ambient temperature constant at a reference temperature T0 (for example, 25°C), the light source control unit 71 first controls the semiconductor laser 2 and modulates the wavelength of the laser light at a predetermined modulation frequency and modulation depth, centering on the peak of the absorption spectrum of the component to be measured. Note that a reference measurement using zero gas may be performed before the reference measurement using span gas to measure the reference correlation value.

[0111] Next, a span gas (gas with known component concentrations) is introduced into cell 1, either by the operator or automatically, and a reference measurement is performed. This reference measurement is performed for both a span gas containing the target component alone and a span gas containing the interfering component alone.

[0112] Specifically, in the reference measurement, the logarithmic calculation unit 61 receives each output signal from the photodetector 5 at each wavelength shift of the reference light and calculates the logarithmic intensity L(t). Then, the correlation value calculation unit 82 calculates the correlation value between the logarithmic intensity L(t) and the three feature signals F1(t), F2(t), and F3(t). By subtracting the reference correlation value from this correlation value and dividing the result by the span gas concentration, the single correlation value, which is the correlation value of each span gas per unit concentration, is calculated. Alternatively, instead of calculating the single correlation value, the relationship between the span gas concentration and the correlation value of the span gas may be stored.

[0113] Specifically, it is as follows: w k By adjusting the settings and introducing a span gas containing the target component alone into cell 1, the correlation value calculation unit 82 calculates the correlation value S of the target component. 1tar (w k ), S 2tar (w k ), S 3tar (w k ) calculates S 1tar (w k ) is the correlation value with the first feature signal, S 2tar (w k ) is the correlation value with the second feature signal, S 3tar (w k ) is the correlation value with the third feature signal. The correlation value calculation unit 82 then calculates these correlation values ​​S 1tar (w k ), S 2tar (w k ), S 3tar (w k ) Reference correlation value R i Subtracting this gives the span gas concentration c of the component being measured. tar By dividing by s, the single correlation value is obtained. 1tar (w k ), s 2tar (w k ), s 3tar (w kThis procedure is repeated by sequentially changing the wavelength shift of the reference light (for example, -0.01 cm) by changing the set temperature of the semiconductor laser 2. -1 ~+0.01cm -1 to 0.001cm -1 The procedure is performed for each wavelength shift, and the relationship between the obtained individual correlation value and its wavelength shift is stored. Note that the span gas concentration c of the component to be measured is also measured. tar This information is input to the signal processing unit 8 in advance by the user or other means.

[0114] Also, the amount of wavelength shift of the reference light is w k By adjusting the settings and introducing a span gas containing the interference component alone into cell 1, the correlation value calculation unit 82 calculates the correlation value S of the interference component. 1int (w k ), S 2int (w k ), S 3int (w k ) calculates S 1int (w k ) is the correlation value with the first feature signal, S 2int (w k ) is the correlation value with the second feature signal, S 3int (w k ) is the correlation value with the third feature signal. The correlation value calculation unit 82 then calculates these correlation values ​​S 1int (w k ), S 2int (w k ), S 3int (w k ) Reference correlation value R i Subtracting this gives the span gas concentration c of the interference component. int By dividing by s, the single correlation value is obtained. 1int (w k ), s 2int (w k ), s 3int (w k This procedure is repeated by sequentially changing the wavelength shift of the reference light (for example, -0.01 cm) by changing the set temperature of the semiconductor laser 2. -1 ~+0.01cm -1 to 0.001cm-1 Perform for each wavelength shift amount, and store the relationship between the individual correlation value at each obtained wavelength shift amount and the wavelength shift amount. Note that the span gas concentration c of the interference component int is input into the signal processing unit 8 by the user or the like in advance.

[0115] The wavelength shift amount w of each reference light calculated as described above k The individual correlation value s 1tar (w k ), s 2tar (w k ), s 3tar (w k ), s 1int (w k ), s 2int (w k ), s 3int (w k ) is stored in the storage unit 83. Note that this reference measurement may be performed before product shipment or may be performed periodically.

[0116] <Sample Measurement> The light source control unit 71 controls the semiconductor laser 2 and modulates the wavelength of the laser light with a predetermined modulation frequency and modulation depth and centered on the peak of the absorption spectrum of the measurement target component. Here, the temperature control unit 72 changes the target temperature of the temperature control unit 3 using the detected temperature obtained by the temperature sensor 4 and the wavelength correction relationship data to correct the wavelength shift of the semiconductor laser 2. Further, the light source control unit 71 changes the drive voltage or drive current of the semiconductor laser 2 using the detected temperature obtained by the temperature sensor 4 and the modulation correction relationship data to correct the modulation width of the semiconductor laser 2.

[0117] Next, the sample gas is introduced into the cell 1 by the operator or automatically, and the sample measurement is performed.

[0118] Specifically, during sample measurement, the logarithmic calculation unit 81 receives the output signal from the photodetector 3 and calculates the logarithmic intensity L(t). Then, the correlation value calculation unit 82 calculates the sample correlation values ​​S1, S2, and S3 between the logarithmic intensity L(t) and multiple feature signals F1(t), F2(t), and F3(t), and from these correlation values, calculates the reference correlation value R i Calculate the sample correlation values ​​S'1 and S'2 after subtracting the specified value.

[0119] Furthermore, the wavelength shift determination unit 84 determines the wavelength shift amount W using the method described above.

[0120] The concentration calculation unit 85 calculates the wavelength shift amount w of each reference light stored in the storage unit 83. k The individual correlation values ​​s′ of the measured component and interference component corrected by the wavelength shift amount W are obtained using the individual correlation values ​​in and the wavelength shift amount W determined by the wavelength shift determination unit 84. 1tar , s' 2tar , s' 1int , s' 2int This determines the result. Possible methods for this determination include using linear interpolation, quadratic interpolation, or spline interpolation.

[0121] Then, the concentration calculation unit 85 calculates the sample correlation values ​​S'1 and S'2, which have been corrected by the reference correlation value calculated by the correlation value calculation unit 82, and the corrected single correlation value s' 1tar , s' 2tar , s' 1int , s' 2int And the concentration C of the target component and each interfering component. tar , C int Solve the following system of two equations consisting of (see Figure 9).

[0122]

number

[0123] Even when it is assumed that there are two or more interfering components, the concentration of the target component from which interference and coexistence effects have been removed can be similarly determined by adding individual correlation values ​​for each interfering component and solving a system of equations with the same number of elements as the number of component species.

[0124] In other words, if there are generally n types of gases, including the component being measured and the interfering component, the corrected single correlation value of the j-th gas type in the i-th feature signal is s'. ij The concentration of the j-th gas species is C j , i-th feature signal F i S is the sample correlation value in (t). i Therefore, the following equation (Equation 5) holds true.

[0125]

number

[0126] By solving the system of n equations represented by this equation (Equation 5), the concentration of each gas of the target component and the interfering component, corrected for interference effects, can be determined. Even if the sample does not contain interfering components, the concentration of each gas of the target component and the interfering component, corrected for interference effects, can still be determined by solving the above system of n equations.

[0127] <Effects of this embodiment> According to the analytical apparatus 100 of this embodiment configured in this way, the drive voltage (or drive current) of the light source control unit 71 is changed based on the temperature detected by the temperature sensor 4 that detects the ambient temperature around the laser light source 2, using modulation correction relationship data that shows the relationship between the ambient temperature of the laser light source 2 and correction parameters for correcting the modulation width deviation of the laser light source 2. As a result, the change in the modulation width of the oscillation wavelength of the laser light source due to changes in ambient temperature can be reduced.

[0128] In particular, in this embodiment, since the wavelength shift and modulation width due to changes in ambient temperature are corrected, the wavelength modulation range when measuring the concentrations of ethane (C2H6), formaldehyde (HCHO), sulfur dioxide (SO2), methane (CH4), methanol (CH3OH), or ethanol (C2H5OH) in the combustion gas, or the wavelength modulation range when measuring the concentrations of carbon dioxide (CO2), carbon monoxide (CO), ethylene (C2H4), ethane (C2H6), water (H2O), acetylene (C2H2), or methane (CH4) in the material gas, can be set with high accuracy, and their concentrations can be measured with high accuracy.

[0129] Furthermore, in addition to the physical wavelength shift correction described above, the amount of wavelength shift W of the reference light is determined by calculation, and the concentration of the target component is calculated using the determined wavelength shift W to further correct for the effect of the wavelength shift of the reference light. This corrects for changes in the optical absorption spectrum of the target component caused by the wavelength shift of the reference light, which cannot be suppressed by physical wavelength shift correction alone, and allows for more accurate measurement of the concentration of the target component.

[0130] Furthermore, according to the analyzer 100 of this embodiment, a logarithmic intensity L(t), which is an intensity-related signal related to the intensity of the sample light, and a plurality of feature signals F for the logarithmic intensity L(t) are obtained. i Correlation values ​​S with (t) i The multiple correlation values ​​S calculated are then calculated. i Since the concentration of the target component is calculated using this method, the characteristics of the absorption signal can be captured with dramatically fewer variables without converting the absorption signal to an absorption spectrum, and the concentration of the target component can be measured with simple calculations without complex spectral processing. For example, while general spectral fitting requires hundreds of data points, this invention allows for concentration calculation with equivalent accuracy using only a few to a few dozen correlation values. As a result, the computational load can be dramatically reduced, eliminating the need for advanced computational processing equipment, thereby reducing the cost of the analytical device 100 and enabling miniaturization. Here, since multiple feature signals are used that yield different correlations from the sinusoidal signal, the concentration of the target component can be determined with accuracy equivalent to or better than that of conventional analytical devices that perform concentration calculations using lock-in detection.

[0131] <Other Embodiments> For example, the logarithmic calculation unit 61 in each of the above embodiments performed logarithmic calculation on the light intensity signal of the photodetector 3, but it may also calculate the logarithm of the ratio of the intensity of the sample light to the intensity of the modulated light, which is the reference light, using the light intensity signal of the photodetector 3 (so-called absorbance). In this case, the logarithmic calculation unit 61 may calculate the absorbance by calculating the logarithm of the intensity of the sample light, then calculating the logarithm of the intensity of the reference light and subtracting them, or it may calculate the absorbance by first finding the ratio of the intensity of the sample light to the intensity of the reference light and then taking the logarithm of that ratio.

[0132] Furthermore, although the correlation value calculation unit 62 in each of the above embodiments calculated the correlation value between the intensity-related signal and the feature signal, it may also calculate the dot product value between the intensity-related signal and the feature signal.

[0133] Furthermore, in addition to the function of correcting wavelength shift of the analytical apparatus 100 in the above embodiment, or instead of the function of correcting wavelength shift, it may also have a function of correcting broadening due to coexisting effects. In this case, as shown in Figure 10, the signal processing unit 8 of the analytical apparatus 100 includes a broadening factor determination unit 86 that determines the broadening factor, which indicates the rate of change in the optical absorption spectrum of the target component or interference component caused by coexisting components contained in the sample.

[0134] The broadening factor determination unit 86 determines the broadening factor F, which indicates the rate of change in the optical absorption spectra of the target component and interference components caused by coexisting components contained in the sample. B This determines the broadening factor F. Furthermore, if the coexisting influence of coexisting components on the interfering component should also be considered, the broadening factor F is used. B It is added and determined for each component.

[0135] Broadening factor F B For example, the following procedures (a) or (b) can be considered as methods for making this decision.

[0136] (a) Each pressure p in the cell k The characteristic signals F of the measured component and the interference component in (k=1,2,···,l) i Each individual correlation value s corresponding to (t) itar (p k ), s iint (p k The broadening factor F is obtained in advance, and the sample correlation value obtained during measurement is compared and matched with the single correlation value to determine the broadening factor F. B This is determined. When comparing and matching, the relationship between the pressure value in the cell and the following formula (Equation 6) is used to convert and use the aforementioned single correlation value. In this method, the number of required feature signals is greater than or equal to the sum of the number of types of components to be measured, the number of types of interference components, and the number of types of broadening factors.

number

[0137] Here, p is the pressure of the sample measured by the pressure sensor 7, F B The broadening factor is determined by the broadening factor determination unit 86, s ij s′ is the individual correlation value for each pressure stored in the storage section 63, ij This is the corrected single correlation value. Note that the above formula (Equation 6) is the single correlation value s at the sample pressure p during sample measurement. ij For (p), the pressure is F B The single correlation value at doubled pressure is 1 / F B By doubling, the corrected single correlation value s′ ij This indicates that we are looking for [something]. Furthermore, if the interfering component is also affected by broadening due to the coexisting component, the broadening factor of the interfering component may be determined separately and the correlation value of the interfering component alone may be corrected. This can further improve the measurement accuracy.

[0138] (b) Concentration of coexisting components and broadening factor F B Using relational data showing the relationship and the measured concentrations of coexisting components, the broadening factor F is calculated. B To decide. At this time, the aforementioned related data is pre-defined as having a broadening factor F for each concentration of the coexisting components. B It is generated by determining it experimentally or by calculation. The measured concentrations of coexisting components may be those measured before correction for coexisting effects using the analytical device 100 of this embodiment, or the concentrations of coexisting components may be measured using a different analytical device.

[0139] The concentration calculation unit 65 calculates the concentration of the target component using multiple sample correlation values ​​obtained by the correlation value calculation unit 62.

[0140] Specifically, the concentration calculation unit 65 uses the multiple sample correlation values ​​obtained by the correlation value calculation unit 62 and the broadening factor F determined by the broadening factor determination unit 64. B Based on the multiple individual correlation values ​​stored in the storage unit 63, the concentration of the target component is calculated. More specifically, the concentration calculation unit 65 calculates the concentration of the target component based on the broadening factor F obtained by the broadening factor determination unit 64. B Then, the multiple individual correlation values ​​stored in the storage unit 63 are corrected and obtained. The concentration calculation unit 65 then uses the multiple sample correlation values ​​obtained by the correlation value calculation unit 62 and the determined broadening factor F B The concentration of the target component is calculated by solving a system of equations consisting of multiple corrected individual correlation values ​​corresponding to the given values, and the concentrations of the target component and each interfering component.

[0141] More specifically, the concentration calculation unit 65 calculates the pressure p in each cell stored in the storage unit 63. k The single correlation value in the cell, the pressure value p measured by the pressure sensor 7, and the broadening factor F determined by the broadening factor determination unit 64. BUsing the above equation (Equation 6), the single correlation value s′ of the measured component corrected for both the pressure in the cell and the broadening factor is obtained. 1tar , s' 2tar And the single correlation value s′ of the interference component corrected only for pressure within the cell (broadening factor set to 1). 1int , s' 2int This determines the result. Possible methods for this determination include using linear interpolation, quadratic interpolation, or spline interpolation.

[0142] Then, the concentration calculation unit 65 corrects the sample correlation values ​​S'1 and S' by the reference correlation value calculated by the correlation value calculation unit 62. 2、 And the corrected single correlation value s′ 1tar , s' 2tar , s' 1int , s' 2int And the concentration C of the target component and the interfering component. tar , C int Solve the following system of two equations consisting of and .

[0143]

number

[0144] This allows us to easily and reliably solve the simultaneous equations in equation (Equation 7) above to obtain the concentration C of the target component, with interference and coexistence effects removed. tar This configuration allows for the determination of the modulation width of the laser light source 2, which can be corrected by the modulation width correction of the laser light source 2 of the present invention. This suppresses changes in the modulation width of the laser light source due to ambient temperature changes and correctly corrects broadening due to coexisting effects, thereby enabling more accurate measurement of the concentration of the target component.

[0145] Furthermore, the analyzer 100 may also include a plurality of laser light sources 2 that irradiate cell 1 with laser light and a plurality of corresponding temperature control units 3, as shown in Figure 11. The plurality of laser light sources 2 may correspond to the target components to be measured as exemplified in the above embodiment. In this analyzer 100, the plurality of laser light sources 2 are pulsed by the light source control unit 71 so that they have the same oscillation period but their oscillation timings are different from each other. Here, the control contents of the light source control unit 71 and temperature control unit 72 for each laser light source 2 and each temperature control unit 3 are the same as in the above embodiment. The signal processing device 6 separates the signals of each of the plurality of laser light sources 2 from the light intensity signal obtained by the photodetector 5, and uses the light absorption signals of each separated laser light source 2 to calculate the concentration of the target component to be measured corresponding to each laser light source 2. The calculation of the concentration of the target component by the signal processing unit 8 is the same as in the above embodiment.

[0146] In the above embodiment, the wavelength shift was corrected both physically and by calculation, but it is also possible not to correct the wavelength shift by calculation. Alternatively, it is possible to correct the wavelength shift by calculation without physically correcting it, or to not correct the wavelength shift physically and not to correct the wavelength shift by calculation.

[0147] Furthermore, in the above embodiment, not only the wavelength shift due to ambient temperature but also the modulation width shift is corrected, but a configuration in which the modulation width shift is not corrected is also possible.

[0148] Furthermore, in each of the above embodiments, the storage unit 83 stores the single correlation value corrected using the reference correlation value. However, it is also possible to store the single correlation value before correction in the storage unit 883, and the concentration calculation unit 83 calculates a corrected single correlation value by subtracting the reference correlation value from the single correlation value before correction and converting it to a value per unit concentration.

[0149] The multiple feature signals are not limited to the above embodiment and may be any functions that are different from each other. Furthermore, as feature signals, for example, functions representing the waveform (sample spectrum) of light intensity, logarithmic intensity, or absorbance obtained by flowing a span gas of known concentration may be used. Also, when measuring the concentration of a single target component, at least one feature signal is sufficient.

[0150] Furthermore, if there are n types of gases, including the target component and interference components, it is also possible to use more than n types of feature signals to obtain a larger number of single correlation values ​​and sample correlation values ​​than the number of gas types, create a system of equations with more elements than the number of gas types, and determine the concentration of each component using the least squares method. In this way, it becomes possible to determine the concentration with less error even when affected by measurement noise.

[0151] Furthermore, the sample gas can be not only exhaust gas but also air, and can be a liquid or a solid. In that sense, the present invention can be applied not only to gases but also to liquids and solids of the components to be measured. In addition, it can be used not only to calculate the absorbance of light that has penetrated through the object to be measured, but also to calculate the absorbance due to reflection.

[0152] The signal processing unit in the above embodiment performs the functions of a correlation value calculation unit that calculates a correlation value dependent on the concentration of the target component using an intensity-related signal related to the intensity of the sample light and a characteristic signal that obtains a predetermined correlation with the intensity-related signal, and a concentration calculation unit that calculates the concentration of the target component using the correlation value obtained by the correlation value calculation unit. However, other calculation methods may also be used.

[0153] The light source is not limited to semiconductor lasers; other types of lasers are also acceptable. Any single-wavelength light source with sufficient full width at half maximum to ensure measurement accuracy and capable of wavelength modulation can be used.

[0154] Furthermore, various modifications and combinations of the embodiments are permitted, as long as they do not contradict the spirit of the present invention. [Industrial applicability]

[0155] According to the present invention, in an analytical device utilizing light absorption, fluctuations in the modulation width of the oscillation wavelength of the laser light source due to changes in ambient temperature can be reduced, thereby enabling accurate measurement of the concentration of the target component. [Explanation of symbols]

[0156] 100...Analyzer 1 ···Cell 2. Laser light source (semiconductor laser) 3...Temperature control section 4 ···Temperature sensor 5 ···Photodetector 6... Signal Processing Device 7 ···Control Unit 81 ···Logarithmic calculation unit 82...Correlation Value Calculation Unit 83 ···Storage Unit 84 ···Wavelength shift determination unit 85...Concentration calculation section

Claims

1. An analytical device for analyzing target components contained in a sample, A laser light source that irradiates the aforementioned sample with reference light, A photodetector that detects the intensity of sample light transmitted through the sample by the reference light, A temperature control unit that adjusts the temperature of the laser light source, A temperature sensor for detecting the ambient temperature of the laser light source, A relational data storage unit stores modulation correction relational data that shows the relationship between the ambient temperature of the laser light source and correction parameters for correcting the deviation of the laser light source from a predetermined modulation range for measuring the component to be measured, An analytical apparatus comprising a control unit that changes at least one of the target temperature of the temperature control unit or the drive voltage or drive current applied for wavelength modulation of the laser light source, using the temperature detected by the temperature sensor and the modulation correction related data.

2. A wavelength shift determination unit that determines the amount of wavelength shift of the reference light from an intensity-related signal related to the intensity of the sample light, The analytical apparatus according to claim 1, further comprising a concentration calculation unit that calculates the concentration of the target component after correcting the wavelength shift of the reference light using an intensity-related signal related to the intensity of the sample light and the wavelength shift amount.

3. The analytical apparatus according to claim 2, wherein the wavelength shift determination unit determines the wavelength shift amount by fitting reference data related to the optical absorption signals of the target component and interference component, whose wavelength shift amounts are known, with sample data related to the optical absorption signal obtained from the intensity of the sample light.

4. A broadening factor determination unit that determines the broadening factor, which represents the rate of change in the optical absorption spectrum of the target component or interference component caused by coexisting components contained in the sample, The analytical apparatus according to any one of claims 1 to 3, further comprising a concentration calculation unit that calculates the concentration of the target component after correcting for the coexistence effect of the coexisting components using an intensity-related signal related to the intensity of the sample light and the broadening factor.

5. The analytical apparatus according to claim 4, wherein the broadening factor determination unit determines the broadening factor by fitting reference data related to the optical absorption signals of the target component and interference component, whose broadening factor or pressure is known, with sample data related to the optical absorption signal obtained from the intensity of the sample light.

6. The analytical apparatus according to claim 4, wherein the broadening factor determination unit determines the broadening factor using relational data showing the relationship between the concentration of the coexisting component and the broadening factor, and the measured concentration of the coexisting component.

7. The analytical apparatus according to any one of claims 1 to 3, wherein the laser light source is a quantum cascade laser.

8. This device measures the concentration of at least one of the following in a combustion gas: nitric oxide, nitrogen dioxide, nitrous oxide, ammonia, ethane, formaldehyde, acetaldehyde, sulfur dioxide, methane, methanol, or ethanol. When measuring the concentration of nitric oxide, the concentration is calculated based on the absorption of nitric oxide between 5.24 and 5.26 μm. When measuring the concentration of nitrogen dioxide, the concentration is calculated based on the absorption of nitrogen dioxide between 6.14 and 6.26 μm. When measuring the concentration of nitrous oxide, the concentration is calculated based on the absorption of nitrous oxide between 7.84 and 7.91 μm. When measuring the ammonia concentration, the concentration is calculated based on the absorption of ammonia between 9.38 and 9.56 μm. When measuring the concentration of ethane, the concentration is calculated based on the absorption of ethane between 3.33 and 3.36 μm. When measuring the concentration of formaldehyde or acetaldehyde, the concentration is calculated based on the absorption of formaldehyde or acetaldehyde between 5.65 and 5.67 μm. When measuring the concentration of sulfur dioxide, the concentration is calculated based on the absorption between 7.38 and 7.42 μm. When measuring the concentration of the aforementioned methane, the concentration is calculated based on the absorption between 7.50 and 7.54 μm. The analytical apparatus according to any one of claims 1 to 3, wherein when measuring the concentration of methanol or ethanol, the concentration is calculated based on absorption between 9.45 and 9.47 μm.

9. This device measures the concentration of at least one of the following in a combustion gas: nitric oxide, nitrogen dioxide, nitrous oxide, ammonia, ethane, formaldehyde, acetaldehyde, sulfur dioxide, methane, methanol, or ethanol. When measuring the concentration of nitric oxide, the concentration is calculated based on the absorption of nitric oxide between 5.245 and 5.247 μm. When measuring the concentration of nitrogen dioxide, the concentration is calculated based on the absorption of nitrogen dioxide between 6.145 and 6.254 μm. When measuring the concentration of nitrous oxide, the concentration is calculated based on the absorption of nitrous oxide between 7.845 and 7.907 μm. When measuring the ammonia concentration, the concentration is calculated based on the absorption of ammonia between 9.384 and 9.557 μm. When measuring the concentration of ethane, the concentration is calculated based on the absorption of ethane between 3.336 and 3.352 μm. When measuring the concentration of formaldehyde or acetaldehyde, the concentration is calculated based on the absorption of formaldehyde or acetaldehyde between 5.651 and 5.652 μm, or between 5.665 and 5.667 μm. When measuring the concentration of sulfur dioxide, the concentration is calculated based on the absorption of sulfur dioxide between 7.385 and 7.417 μm. When measuring the concentration of methane, the concentration is calculated based on the absorption of methane between 7.503 and 7.504 μm, or between 7.535 and 7.536 μm. The analytical apparatus according to any one of claims 1 to 3, wherein, when measuring the concentration of methanol or ethanol, the concentration is calculated based on the absorption of methanol or ethanol between 9.467 and 9.468 μm, or between 9.455 and 9.456 μm.

10. This device measures the concentration of at least one of the following in a combustion gas: nitric oxide, nitrogen dioxide, nitrous oxide, ammonia, ethane, formaldehyde, acetaldehyde, sulfur dioxide, methane, methanol, or ethanol. When measuring the concentration of nitric oxide, the concentration is calculated based on the absorption of nitric oxide at 5.2462 μm. When measuring the concentration of nitrogen dioxide, the concentration is calculated based on the absorption of nitrogen dioxide at 6.2322 μm or 6.2538 μm. When measuring the concentration of nitrous oxide, the concentration is calculated based on the absorption of nitrous oxide at 7.8455 μm, 7.8509 μm, 7.8784 μm, or 7.9067 μm. When measuring the concentration of ammonia, the concentration is calculated based on the absorption of ammonia at 9.3847 μm or 9.5566 μm. When measuring the concentration of ethane, the concentration is calculated based on the absorption of ethane at 3.3368 μm, 3.3482 μm, or 3.3519 μm. When measuring the concentration of formaldehyde or acetaldehyde, the concentration is calculated based on the absorption of formaldehyde or acetaldehyde at 5.6514 μm or 5.6660 μm. When measuring the concentration of sulfur dioxide, the concentration is calculated based on the absorption of sulfur dioxide at 7.3856 μm or 7.4163 μm. When measuring the concentration of methane, the concentration is calculated based on the absorption of methane at 7.5035 μm or 7.5354 μm. The analytical apparatus according to any one of claims 1 to 3, wherein, when measuring the concentration of methanol or ethanol, the concentration is calculated based on the absorption of methanol or ethanol at 9.4671 μm or 9.4557 μm.

11. This device measures the concentration of at least one of the following in a process gas: carbon dioxide, carbon monoxide, ethylene, ethane, water, acetylene, methane, ammonia, and methanol. When measuring the carbon dioxide concentration, the concentration is calculated based on the absorption of carbon dioxide between 4.23 and 4.24 μm, or between 4.34 and 4.35 μm. When measuring the carbon monoxide concentration, the concentration is calculated based on the absorption of carbon monoxide between 4.59 and 4.61 μm. When measuring the concentration of the water, the concentration is calculated based on the absorption of water between 5.89 and 6.12 μm. When measuring the concentration of acetylene, the concentration is calculated based on the absorption of acetylene between 7.56 and 7.66 μm, or between 7.27 and 7.81 μm. When measuring the concentration of methane, the concentration is calculated based on the absorption of methane between 7.67 and 7.80 μm, or between 8.10 and 8.14 μm. When measuring the ethylene concentration, the concentration is calculated based on the absorption of ethylene between 8.46 and 8.60 μm. When measuring the concentration of ethane, the concentration is calculated based on the absorption of ethane between 6.13 and 6.14 μm, or between 6.09 and 6.45 μm. When measuring the ammonia concentration, the concentration is calculated based on the absorption of ammonia between 6.06 and 6.25 μm, or between 8.62 and 9.09 μm. The analytical apparatus according to any one of claims 1 to 3, wherein, when measuring the concentration of methanol, the concentration is calculated based on the absorption of methanol between 9.35 and 9.62 μm.

12. This device measures the concentration of at least one of the following in a process gas: carbon dioxide, carbon monoxide, ethylene, ethane, water, acetylene, methane, ammonia, and methanol. When measuring the carbon dioxide concentration, the concentration is calculated based on the absorption of carbon dioxide between 4.234 and 4.238 μm, or between 4.342 and 4.347 μm. When measuring the carbon monoxide concentration, the concentration is calculated based on the absorption of carbon monoxide between 4.594 and 4.604 μm. When measuring the concentration of the water, the concentration is calculated based on the absorption of water between 5.896 and 5.934 μm, or between 6.046 and 6.114 μm. When measuring the concentration of acetylene, the concentration is calculated based on the absorption of acetylene between 7.378 and 7.638 μm, between 7.378 and 7.603 μm, between 7.629 and 7.683 μm, between 7.594 and 7.651 μm, or between 7.566 and 7.634 μm. When measuring the concentration of methane, the concentration is calculated based on the absorption of methane between 7.670 and 7.792 μm, between 8.107 and 8.139 μm, or between 8.102 and 8.121 μm. When measuring the ethylene concentration, the concentration is calculated based on the absorption of ethylene between 8.464 and 8.599 μm. When measuring the concentration of ethane, the concentration is calculated based on the absorption of ethane between 6.135 and 6.139 μm, or between 6.463 and 6.619 μm. When measuring the ammonia concentration, the concentration is calculated based on the absorption of ammonia between 6.141 and 6.153 μm, or between 8.939 and 8.968 μm. The analytical apparatus according to any one of claims 1 to 3, wherein, when measuring the concentration of methanol, the concentration is calculated based on the absorption of methanol between 9.477 and 9.526 μm.

13. This device measures the concentration of at least one of the following in a process gas: carbon dioxide, carbon monoxide, ethylene, ethane, water, acetylene, methane, ammonia, and methanol. When measuring the carbon dioxide concentration, the concentration is calculated based on the absorption of carbon dioxide at 4.2347 μm, 4.2371 μm, 4.3428 μm, or 4.3469 μm. When measuring the concentration of carbon monoxide, the concentration is calculated based on the absorption of carbon monoxide at 4.5950 μm or 4.6024 μm. When measuring the concentration of the water, the concentration is calculated based on the absorption of water at 5.8965 μm, 5.9353 μm, 6.0486 μm, or 6.1138 μm. When measuring the concentration of acetylene, the concentration is calculated based on the absorption of acetylene at 7.5966 μm, 7.6233 μm, 7.6501 μm, 7.5698 μm, 7.6367 μm, or 7.6231 μm. When measuring the concentration of methane, the concentration is calculated based on the absorption of methane at 7.6704 μm, 7.7914 μm, 8.1073 μm, 8.1381 μm, 8.1022 μm, or 8.1206 μm. When measuring the ethylene concentration, the concentration is calculated based on the absorption of ethylene at 8.4647 μm or 8.5981 μm. When measuring the concentration of ethane, the concentration is calculated based on the absorption of ethane at 6.1384 μm, 6.4673 μm, 6.5008 μm, 6.5624 μm, or 6.6145 μm. When measuring the ammonia concentration, the concentration is calculated based on the absorption of ammonia at 6.1450 μm, 6.1487 μm, 6.1496 μm, 8.9604 μm, 8.9473 μm, or 8.7671 μm. The analytical apparatus according to any one of claims 1 to 3, wherein, when measuring the concentration of methanol, the concentration is calculated based on the absorption of methanol at 9.5168 μm, 9.5042 μm, or 9.4861 μm.

14. A program applied to an analytical apparatus that analyzes a target component contained in a sample, comprising a laser light source for irradiating a sample with reference light, a photodetector for detecting sample light transmitted through the sample, a temperature control unit for adjusting the temperature of the laser light source, and a temperature sensor for detecting the ambient temperature around the laser light source, A relational data storage unit stores modulation correction relational data that shows the relationship between the ambient temperature of the laser light source and correction parameters for correcting the deviation of the laser light source from a predetermined modulation range for measuring the component to be measured, A program for an analytical apparatus, characterized in that it causes the analytical apparatus to function as a control unit that changes at least one of the target temperature of the temperature control unit or the drive voltage or drive current applied for wavelength modulation of the laser light source, using the temperature detected by the temperature sensor and the modulation correction related data.

15. An analytical method for analyzing a target component contained in a sample, using an analytical apparatus comprising a laser light source for irradiating a sample with reference light, a photodetector for detecting sample light transmitted through the sample, a temperature control unit for adjusting the temperature of the laser light source, and a temperature sensor for detecting the ambient temperature around the laser light source, An analysis method comprising referring to modulation correction relation data that shows the relationship between the ambient temperature of the laser light source and correction parameters for correcting deviations of the laser light source from a predetermined modulation range for measuring the component to be measured, and using the modulation correction relation data to change at least one of the target temperature of the temperature control unit or the drive voltage or drive current applied for wavelength modulation of the laser light source.

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