JP5363148B2 - Hydrocarbon concentration measuring apparatus and hydrocarbon concentration measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instrument and method for measuring the concentration of hydrocarbon with high accuracy, by eliminating the influence due to a disturbance factor which varies from moment to moment. <P>SOLUTION: A THC (total hydrocarbon) measuring device 100 includes: an infrared lamp 10; a spectrometer 20; a photodiode 30; a gas vessel 40 capable of storing gas 1 to be measured and transmitting light; and a data processor 190 for calculating a second correction reference spectrum, calculated based on a reference spectrum, a third correction absorption spectrum calculated based on the absorption spectrum of the gas 1 to be measured, and an absorbed amount of light of a wavelength band absorbed by each group of (a) alkane and alkene, (b) aromatic hydrocarbon, and (c) alkyne of hydrocarbon contained in the gas 1 to be measured based on a calculation formula by Lambert-Beer Law, and calculating the concentration of the hydrocarbon of each group based on the amount of the light of each group. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  In the present invention, among hydrocarbons, (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes each absorb light in different wavelength bands. The present invention relates to a hydrocarbon concentration measuring apparatus that uses and measures the sum of the concentrations of hydrocarbons belonging to each group contained in a measurement target gas based on the amount of light absorbed in a wavelength band corresponding to each group.

  Conventionally, technologies for measuring the concentration of hydrocarbons contained in exhaust gases of automobiles and the like are classified according to the measurement principle. Typical ones are those using a flame ionization detector (FID), non-dispersive infrared rays. The thing using the analysis method (Non-Dispersive Infrared Analyzer) is known. As a technique using a non-dispersive infrared analysis method, a technique described in Patent Document 1 is known.

  However, the technique using the flame ionization method is to count the number of carbon atoms contained in the gas to be measured, and the measurement accuracy itself is high, but it is included in the gas to be measured. In other words, the composition of each hydrocarbon species cannot be measured, and it is unsuitable for real-time measurement.

In principle, the technology using non-dispersive infrared analysis can measure non-contact concentration of hydrocarbons in real time with no response delay. However, hydrocarbons have their own absorption wavelength band (absorption). Therefore, it is necessary to prepare a light source and a light receiving element that generate light in a wavelength band corresponding to each type of hydrocarbon contained in the gas to be measured.
In particular, since the types of hydrocarbons contained in the exhaust gas of automobiles and the like exceed 200 types in some cases, the apparatus becomes very large when light sources and light receiving elements corresponding to all types of hydrocarbons are prepared, In addition, there is a problem that the manufacturing cost of the device becomes enormous.

As a technique for solving the above-mentioned problem, the applicants stated that “a gas having a wavelength band including an absorption region common to the one or more chemical species in a gas (measurement target gas) containing a hydrocarbon composed of one or more chemical species. An absorbance that irradiates the light, a detector that detects the light emitted to the gas by the irradiator, and an absorbance of the common absorption region based on the light detected by the detector, and the absorbance And a analyzer for calculating the sum of the concentrations of chemical species that absorb light in the wavelength band of the common absorption region based on the above-mentioned (Japanese Patent Application No. 2007-289766). reference).
In this technique, for example, among hydrocarbons, (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes absorb light in different wavelength bands. By detecting the amount of light absorbed in the wavelength band corresponding to each group, the concentration (sum) of hydrocarbons belonging to each group can be detected, and the number of light sources and light receiving elements required for the device is reduced. The device can be miniaturized.

  The hydrocarbon concentration measuring apparatus proposed by the above-mentioned applicants is provided with a pair of windows made of quartz or sapphire glass, for example, in a metal cylindrical gas container containing a measurement target gas, and the light from the irradiation unit The light is guided from one side of the gas container to the inside of the gas container, the light transmitted through the gas to be measured in the gas container is guided from the other window to the outside of the container, and the detection unit detects the light guided to the outside. The concentration of the hydrocarbon belonging to each group of (a) to (c) is calculated.

  The hydrocarbon concentration measuring apparatus proposed by the above-mentioned applicants, when calculating the concentration of hydrocarbons belonging to each of the groups (a) to (c) above, is the Lambert-Beer law (Lambert) -Absorbance in the wavelength band absorbed by the hydrocarbons belonging to each of the groups (a) to (c) is calculated according to a calculation formula based on (Beer law).

In Equation 3, An indicates absorbance (absorption amount of light), In indicates the intensity of light transmitted through the absorption wavelength band to be measured when the measurement target gas is irradiated with light, and (In) ₀ is It refers to the intensity of light that passes through the absorption wavelength band that is the target when the reference gas is irradiated with light.
The value of (In) ₀ is usually set before the start of measurement or by calibration work at regular intervals.

However, the hydrocarbon concentration measuring device proposed by the applicants is as follows: (1) the irradiation unit (light source) or the detection unit of the hydrocarbon concentration measuring device proposed by the applicants is deteriorated; (2) hydrocarbon concentration The optical system (lens, etc.) of the measuring device or the window provided in the gas container becomes dirty. (3) The gas container is heated by heat conduction from the gas to be measured, and the gas container is made red from the material (metal, etc.). The intensity of light detected by the detector changes due to a disturbance factor such as external light being emitted, and the calculation result of the absorbance in the wavelength band absorbed by the hydrocarbons belonging to each of the groups (a) to (c) above There is a problem that reliability, and consequently, the measurement accuracy of the hydrocarbon concentration measuring apparatus proposed by the applicants is lowered.
In particular, when the measurement target gas is an automobile exhaust gas, the degree of disturbance factors (the magnitude of the influence on the measurement accuracy) of (2) and (3) above may vary from time to time during measurement. It is difficult to ensure sufficient measurement accuracy only by calibration before starting measurement.

JP-A-4-225142

  In view of the circumstances as described above, the present invention provides a hydrocarbon concentration measuring apparatus and a hydrocarbon concentration measuring method capable of accurately measuring the hydrocarbon concentration by eliminating the influence of disturbance factors that change every moment. To do.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in claim 1,
A light source that generates light;
A spectroscope for periodically changing the wavelength of the light generated by the light source;
A light receiver for detecting the intensity of light whose wavelength has been varied by the spectroscope;
The optical path formed by the light source, the spectroscope and the light receiver is disposed at a position sandwiched by the spectroscope and the light receiver or a position sandwiched by the light source and the spectroscope, and can accommodate a measurement target gas, and A gas container capable of transmitting light;
Among the hydrocarbons contained in the measurement target gas, the shortest wavelength point in the reference spectrum from the reference spectrum including the wavelength band absorbed by each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbon, and the group consisting of alkyne. A second corrected reference spectrum obtained by adding a constant to the first corrected reference spectrum calculated by subtracting the light intensity of the light intensity at the longest wavelength point and the light intensity at the longest wavelength point is stored in advance and detected by the light receiver. By calculating the absorption spectrum of the gas to be measured based on the intensity of the measured light, and subtracting the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the absorption spectrum from the absorption spectrum. Calculate the first corrected absorption spectrum, the first correction The light intensity of the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the reference spectrum is the greater of the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the first corrected absorption spectrum. A second corrected absorption spectrum is calculated by multiplying the first corrected absorption spectrum by a value divided by the intensity, a third corrected absorption spectrum is calculated by adding the constant to the second corrected absorption spectrum, and the second corrected absorption spectrum is calculated. Of the hydrocarbons contained in the measurement target gas based on the corrected reference spectrum, the third corrected absorption spectrum, and the following Equation 1, a group consisting of alkane and alkene, a group consisting of aromatic hydrocarbons, a group consisting of alkynes, Calculate the amount of light absorption in the wavelength band that each absorbs, and apply to each calculated group. A density calculating apparatus for calculating the concentration of hydrocarbons belonging to each group based on the absorption of light,
It comprises.

In claim 2,
The constant is zero or a positive value.

In claim 3,
A light source that generates light;
A spectroscope for periodically changing the wavelength of the light generated by the light source;
A light receiver for detecting the intensity of light whose wavelength has been varied by the spectroscope;
The optical path formed by the light source, the spectroscope and the light receiver is disposed at a position sandwiched by the spectroscope and the light receiver or a position sandwiched by the light source and the spectroscope, and can accommodate a measurement target gas, and A gas container capable of transmitting light;
Of the hydrocarbons contained in the measurement target gas, a wavelength that is equal to or less than the non-absorption wavelength of the reference spectrum including the wavelength band that each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbon, and the group consisting of alkyne absorbs. Dividing into a short wavelength side reference spectrum consisting of a band and a long wavelength side reference spectrum consisting of a wavelength band equal to or greater than the non-absorption wavelength, and subtracting the light intensity at the shortest wavelength point in the short wavelength side reference spectrum from the short wavelength side reference spectrum The first correction reference spectrum on the short wavelength side calculated by subtracting the light intensity at the longest wavelength point in the long wavelength side reference spectrum from the long wavelength side reference spectrum. The second corrected reference spectrum calculated in advance is stored by subtracting the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the reference spectrum and adding a constant from the reference spectrum. The absorption spectrum of the measurement target gas is calculated based on the intensity of light detected by the light receiver, and the absorption spectrum includes a short wavelength side absorption spectrum having a wavelength band equal to or less than the non-absorption wavelength and the non-absorption Dividing into a long wavelength side absorption spectrum consisting of a wavelength band equal to or greater than the wavelength, and subtracting the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum from the short wavelength side absorption spectrum, the short wavelength side first corrected absorption spectrum Calculated from the long wavelength side absorption spectrum to the long wavelength side absorption spectrum. The long wavelength side first corrected absorption spectrum is calculated by subtracting the light intensity at the longest wavelength point, and the light intensity at the longest wavelength point of the short wavelength side first corrected reference spectrum is calculated from the short wavelength side first corrected absorption spectrum. The short wavelength side second corrected absorption spectrum is calculated by multiplying the short wavelength side first corrected absorption spectrum by the value divided by the light intensity at the longest wavelength point, and the shortest wavelength point of the long wavelength side first corrected reference spectrum is calculated. A long wavelength side second corrected absorption spectrum is calculated by multiplying the long wavelength side first corrected absorption spectrum by dividing the light intensity by the light intensity at the shortest wavelength point of the long wavelength side first corrected absorption spectrum, When the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is smaller than the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the short wavelength side second correction is performed. A short wavelength side third corrected absorption spectrum is calculated by adding a constant to the absorption spectrum, and the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum and the long wavelength side absorption spectrum are added to the long wavelength side second corrected absorption spectrum. The long-wavelength-side third corrected absorption spectrum is calculated by adding the absolute value of the difference from the light intensity at the longest wavelength point and the constant, and the light intensity at the shortest wavelength point in the short-wavelength side absorption spectrum is the long-wavelength side. When the light intensity at the longest wavelength point in the absorption spectrum is larger than the light intensity at the longest wavelength point in the short wavelength side absorption spectrum, The third corrected absorption spectrum on the short wavelength side is calculated by adding the absolute value of the difference from the light intensity and the above constant. And calculating the long wavelength side third corrected absorption spectrum by adding the constant to the long wavelength side second corrected absorption spectrum, and setting the longest wavelength point of the short wavelength side third corrected absorption spectrum to the long wavelength side third corrected spectrum. A third corrected absorption spectrum is generated by connecting to the shortest wavelength point of the corrected absorption spectrum, and the carbonization contained in the measurement target gas based on the second corrected reference spectrum, the third corrected absorption spectrum, and the following Equation 1 Calculates the amount of light absorbed in the wavelength band absorbed by each of the groups consisting of alkanes and alkenes, groups composed of aromatic hydrocarbons, and groups composed of alkynes of hydrogen, and absorbs the light corresponding to each calculated group. A concentration calculation device for calculating the concentration of hydrocarbons belonging to each group based on the amount;
It comprises.

In claim 4,
The constant is zero or a positive value.

In claim 5 ,
A light source that generates light;
A spectroscope for periodically changing the wavelength of the light generated by the light source;
A light receiver for detecting the intensity of light whose wavelength has been varied by the spectroscope;
The optical path formed by the light source, the spectroscope and the light receiver is disposed at a position sandwiched by the spectroscope and the light receiver or a position sandwiched by the light source and the spectroscope, and can accommodate a measurement target gas, and A gas container capable of transmitting light;
Among the hydrocarbons contained in the measurement target gas, the shortest wavelength point in the reference spectrum from the reference spectrum including the wavelength band absorbed by each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbon, and the group consisting of alkyne. The second correction reference spectrum obtained by adding a constant to the first correction reference spectrum calculated by subtracting the light intensity of the light intensity at the longest wavelength point and the light intensity at the longest wavelength point is stored in advance and detected by the light receiver. A concentration calculating device that calculates the concentration of hydrocarbons contained in the measurement target gas based on the intensity of the emitted light;
A hydrocarbon concentration measuring method for measuring the concentration of hydrocarbons contained in the measurement target gas using a hydrocarbon concentration measuring apparatus comprising:
A detection step in which the light receiver detects the intensity of light generated by the light source and transmitted through the measurement target gas contained in the gas container;
An absorption spectrum calculating step in which the concentration calculating device calculates an absorption spectrum of the gas to be measured based on the intensity of light detected by the light receiver;
The concentration calculating device calculates a first corrected absorption spectrum by subtracting the light intensity of the light wavelength at the shortest wavelength point and the light intensity at the longest wavelength point in the absorption spectrum from the absorption spectrum, and calculating a first corrected absorption spectrum. Spectrum calculation step;
The concentration calculation device uses the light intensity at the shortest wavelength point in the first corrected absorption spectrum and the light intensity at the shortest wavelength point in the first corrected absorption spectrum. A second corrected absorption spectrum calculating step of calculating a second corrected absorption spectrum by multiplying the first corrected absorption spectrum by a value obtained by dividing the light intensity of the point by the larger light intensity;
A third corrected absorption spectrum calculating step in which the concentration calculating device calculates a third corrected absorption spectrum by adding the constant to the second corrected absorption spectrum;
From the aromatic hydrocarbon, the group consisting of alkane and alkene among the hydrocarbons contained in the gas to be measured based on the second corrected reference spectrum, the third corrected absorption spectrum, and the following formula 1, A light absorption amount calculating step for calculating an absorption amount of light in a wavelength band absorbed by each of the group consisting of alkyne,
The concentration calculation device calculates the concentration of hydrocarbons belonging to each group based on the amount of light absorbed by each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbons, and the group consisting of alkynes. A concentration calculation step;
It comprises.

In claim 6 ,
The constant is zero or a positive value.

In claim 7 ,
A light source that generates light;
A spectroscope for periodically changing the wavelength of the light generated by the light source;
A light receiver for detecting the intensity of light whose wavelength has been varied by the spectroscope, a position sandwiched by the spectroscope and the light receiver in the optical path formed by the light source, the spectroscope and the light receiver, or the light source and the light source A gas container arranged at a position sandwiched by a spectroscope, capable of containing a gas to be measured and capable of transmitting the light;
Of the hydrocarbons contained in the measurement target gas, a wavelength that is equal to or less than the non-absorption wavelength of the reference spectrum including the wavelength band that each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbon, and the group consisting of alkyne absorbs. Dividing into a short wavelength side reference spectrum consisting of a band and a long wavelength side reference spectrum consisting of a wavelength band equal to or greater than the non-absorption wavelength, and subtracting the light intensity at the shortest wavelength point in the short wavelength side reference spectrum from the short wavelength side reference spectrum The first correction reference spectrum on the short wavelength side calculated by subtracting the light intensity at the longest wavelength point in the long wavelength side reference spectrum from the long wavelength side reference spectrum. The second corrected reference spectrum calculated in advance is stored by subtracting the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the reference spectrum and adding a constant from the reference spectrum. A concentration calculating device that stores the concentration of hydrocarbons contained in the measurement target gas based on the intensity of light detected by the light receiver;
A hydrocarbon concentration measuring method for measuring the concentration of hydrocarbons contained in the measurement target gas using a hydrocarbon concentration measuring apparatus comprising:
A detection step in which the light receiver detects the intensity of light generated by the light source and transmitted through the measurement target gas contained in the gas container;
An absorption spectrum calculating step in which the concentration calculating device calculates an absorption spectrum of the gas to be measured based on the intensity of light detected by the light receiver;
The concentration calculation device divides the absorption spectrum into a short wavelength side absorption spectrum consisting of a wavelength band equal to or less than the non-absorption wavelength and a long wavelength side absorption spectrum consisting of a wavelength band equal to or greater than the non-absorption wavelength, and the short wavelength side The short wavelength side first corrected absorption spectrum is calculated by subtracting the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum from the absorption spectrum and the longest wavelength point in the long wavelength side absorption spectrum is calculated from the long wavelength side absorption spectrum. A first corrected absorption spectrum calculating step of calculating a long wavelength side first corrected absorption spectrum by subtracting the light intensity;
The concentration calculating device calculates a value obtained by dividing the light intensity at the longest wavelength point of the short wavelength side first corrected reference spectrum by the light intensity at the longest wavelength point of the short wavelength side first corrected absorption spectrum. The short-wavelength-side second corrected absorption spectrum is calculated by multiplying the corrected absorption spectrum, and the light intensity at the shortest wavelength point of the long-wavelength-side first corrected reference spectrum is calculated at the shortest-wavelength-side first corrected absorption spectrum. A second corrected absorption spectrum calculating step of calculating a long wavelength side second corrected absorption spectrum by multiplying the long wavelength side first corrected absorption spectrum by a value divided by the light intensity;
When the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is smaller than the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the concentration calculation device has a constant in the short wavelength side second corrected absorption spectrum. And calculating the short wavelength side third corrected absorption spectrum and adding the long wavelength side second corrected absorption spectrum to the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum and the longest wavelength in the long wavelength side absorption spectrum. The long wavelength side third corrected absorption spectrum is calculated by adding the absolute value of the difference from the light intensity at the point and the constant to calculate the longest wavelength point of the short wavelength side third corrected absorption spectrum, and the long wavelength side third corrected A third corrected absorption spectrum is generated by connecting to the shortest wavelength point of the absorption spectrum, and in the short wavelength side absorption spectrum When the light intensity at the short wavelength point is larger than the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is added to the short wavelength side second corrected absorption spectrum. By calculating the short wavelength side third corrected absorption spectrum by adding the absolute value of the difference from the light intensity at the longest wavelength point in the long wavelength side absorption spectrum and the constant, the long wavelength side second corrected absorption spectrum A long wavelength side third corrected absorption spectrum is calculated by adding a constant, and the longest wavelength point of the short wavelength side third corrected absorption spectrum is connected to the shortest wavelength point of the long wavelength side third corrected absorption spectrum. A third corrected absorption spectrum calculating step for generating a three corrected absorption spectrum;
From the aromatic hydrocarbon, the group consisting of alkane and alkene among the hydrocarbons contained in the gas to be measured based on the second corrected reference spectrum, the third corrected absorption spectrum, and the following formula 1, A light absorption amount calculating step for calculating an absorption amount of light in a wavelength band absorbed by each of the group consisting of alkyne,
The concentration calculation device calculates the concentration of hydrocarbons belonging to each group based on the amount of light absorbed by each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbons, and the group consisting of alkynes. A concentration calculation step;
It comprises.

In claim 8 ,
The constant is zero or a positive value.

  The present invention has an effect that it is possible to accurately measure the hydrocarbon concentration by eliminating the influence of disturbance factors that change from moment to moment.

The figure which shows 1st embodiment, 2nd embodiment, and 3rd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the optical system of 1st embodiment, 2nd embodiment, and 3rd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the reference spectrum in 1st embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 1st correction | amendment reference spectrum in 1st embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 2nd correction | amendment reference spectrum in 1st embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the absorption spectrum in 1st embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 1st correction | amendment absorption spectrum in 1st embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 2nd correction | amendment absorption spectrum in 1st embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 3rd correction | amendment absorption spectrum in 1st embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The flowchart which shows 1st embodiment of the hydrocarbon concentration measuring method which concerns on this invention. The figure which shows the short wavelength side reference spectrum, long wavelength side reference spectrum, and reference spectrum in 2nd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the short wavelength side 1st correction reference spectrum and the long wavelength side 1st correction reference spectrum in 2nd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the short wavelength side 2nd correction reference spectrum, the long wavelength side 2nd correction reference spectrum, and the 2nd correction reference spectrum in 2nd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the short wavelength side absorption spectrum, long wavelength side absorption spectrum, and absorption spectrum in 2nd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the short wavelength side 1st correction | amendment absorption spectrum and long wavelength side 1st correction | amendment absorption spectrum in 2nd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the short wavelength side 2nd corrected absorption spectrum and the long wavelength side 2nd corrected absorption spectrum in 2nd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the short wavelength side 3rd corrected absorption spectrum, the long wavelength side 3rd corrected absorption spectrum, and the 3rd corrected absorption spectrum in 2nd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The flowchart which shows 2nd embodiment of the hydrocarbon concentration measuring method which concerns on this invention. The figure which shows the reference spectrum in 3rd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the absorption spectrum in 3rd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the correction | amendment absorption spectrum in 3rd embodiment of the hydrocarbon concentration measuring apparatus which concerns on this invention. The flowchart which shows 3rd embodiment of the hydrocarbon concentration measuring method which concerns on this invention.

  Hereinafter, a THC measuring apparatus 100 as a first embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIGS. 1 to 9.

A THC measurement device 100 shown in FIG. 1 is a device that measures the total concentration of hydrocarbons (Total Hydrocarbon) contained in the measurement target gas 1.
“Measurement gas” broadly refers to a gas containing hydrocarbons at least in part. Specific examples of “measurement target gas” include automobile exhaust gas.
The hydrocarbon contained in the measurement target gas is not necessarily vaporized at normal temperature (25 ° C.) and normal pressure (1 atm), and may be vaporized by heating, for example.
“Hydrocarbon” includes one or more chemical species which are compounds composed of carbon and hydrogen.
Chemical species contained in hydrocarbons are classified into alkanes, alkenes, alkynes, aromatic hydrocarbons and the like based on their structures.
“Alkane” refers to a chain saturated hydrocarbon represented by the general formula C _n H _{2n + 2} (n: an integer of 1 or more). In the present invention, cycloalkane is included in alkane.
“Cycloalkane” refers to a cyclic saturated hydrocarbon represented by the general formula C _n H _2n (n: an integer of 3 or more).
“Alkene” refers to a chain unsaturated hydrocarbon represented by the general formula C _n H _2n (n: an integer of 2 or more).
“Alkyne” refers to a chain unsaturated hydrocarbon represented by the general formula C _n H _2n-2 (n; an integer of 2 or more).
An “aromatic hydrocarbon” is a hydrocarbon having a single ring or a plurality of ring (fused ring) structures.

The THC measuring apparatus 100 of the present embodiment includes (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) an alkyne among the hydrocarbons contained in the measurement target gas 1. By utilizing the property that the hydrocarbons belonging to each group absorb light in different wavelength bands and detecting the amount of light absorbed in the wavelength bands corresponding to each group, the concentration sum of the hydrocarbons belonging to each group is calculated. taking measurement.
Note that "alkane and wavelength range hydrocarbons are absorbed belonging to the group consisting of alkene" is set in the range of, in terms of wavenumber 2800 cm ^-1 or 3000 cm ^-1 or less in the wavelength band, consisting of "aromatic hydrocarbon waveband hydrocarbons belonging to the group to absorb "is set in the range of, in terms of wavenumber 3000 cm ^-1 or 3200 cm ^-1 or less in the wavelength band," waveband hydrocarbons belonging to the group consisting of alkynes absorb light " Is set within the wavelength range of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number.

  The THC measurement device 100 includes a frame 110, a light source side optical system unit 120, a gas container 40, a photodiode 30, a chopper / spectrometer control device 70, a lock-in amplifier 80, and a data processing device 190.

The frame 110 is a structure for holding the relative positions of other members of the THC measuring apparatus 100, particularly members constituting the optical system.
The frame 110 includes a base member 111, a unit support member 112, a container support member 113, and a photodiode support member 114.

  The base member 111 is a member that forms the main structure of the frame 110. Other members constituting the frame 110 are fixed to the base member 111.

  The unit support member 112 is a member that fixes the light source side optical system unit 120 to the base member 111. The lower end portion of the unit support member 112 is fixed to the base member 111, and the upper end portion of the unit support member 112 is fixed to the light source side optical system unit 120.

  The container support member 113 is a member that fixes the gas container 40 to the base member 111. The lower end portion of the container support member 113 is fixed to the base member 111, and the upper end portion of the container support member 113 is fixed to the gas container 40.

  The photodiode support member 114 is a member that fixes the photodiode 30 to the base member 111. The lower end portion of the photodiode support member 114 is fixed to the base member 111, and the upper end portion of the photodiode support member 114 is fixed to the photodiode 30.

The light source side optical system unit 120 is a group of members arranged closer to the infrared lamp 10 than the gas container 40 in the optical system of the THC measuring apparatus 100.
The light source side optical system unit 120 includes a case 121, an infrared lamp 10, a first condenser lens 61, a light chopper 50, a collimator lens 62, a spectrometer 20, and a second condenser lens 63.

The case 121 is a box-shaped member, and accommodates other members constituting the light source side optical system unit 120 and holds the relative positional relationship of the other members.
The case 121 is fixed to the base member 111 via the unit support member 112.
Details of each member housed in the light source side optical system unit 120 (members forming the optical system of the THC measuring apparatus 100) will be described later.

The gas container 40 is an embodiment of the gas container according to the present invention, and is a container that houses the measurement target gas 1.
The gas container 40 of the present embodiment includes a body member 41, an inlet side window member 42, and an outlet side window member 43.

The body member 41 is a cylindrical member forming the main structure of the gas container 40.
The body member 41 is connected to a middle part of the pipe through which the measurement target gas 1 passes, and the measurement target gas 1 passes through the inside of the body member 41. The body member 41 is fixed to the base member 111 via the container support member 113.

  The entrance side window member 42 and the exit side window member 43 are members made of glass or quartz fitted into two openings formed in the body member 41.

  The photodiode 30 is fixed to the base member 111 via the photodiode support member 114. Details of the photodiode 30 will be described later.

Hereinafter, the optical system of the THC measurement apparatus 100 will be described.
As shown in FIG. 2, the optical system of the THC measurement apparatus 100 includes an infrared lamp 10, a spectroscope 20, a photodiode 30, a first condenser lens 61, a collimator lens 62, a second condenser lens 63, and an optical chopper 50. Composed.

The infrared lamp 10 is an embodiment of a light source according to the present invention, and is a member that forms the most upstream part of the optical system of the THC measurement apparatus 100.
As shown in FIG. 1, the infrared lamp 10 is fixed at a predetermined position inside the case 121.
The infrared lamp 10 of the present embodiment generates infrared light, and the wavelength band of the infrared light generated by the infrared lamp 10 is “a hydrocarbon absorbed in the group consisting of alkane and alkene”. "(B) Wavelength band absorbed by hydrocarbons belonging to the group consisting of aromatic hydrocarbons" and "(c) Wavelength band absorbed by hydrocarbons belonging to the group consisting of alkynes" ( (See FIG. 3 and FIG. 6).

The infrared lamp 10 of the present embodiment generates infrared light, but the light source according to the present invention is not limited to this. This is because the light (wavelength) generated by the light source according to the present invention is appropriately selected according to the wavelength band absorbed by the measurement target gas.
That is, the light generated by the light source according to the present invention may be not only infrared light but also visible light and ultraviolet light.

The spectroscope 20 is an embodiment of the spectroscope according to the present invention, and periodically changes the wavelength of light generated by the infrared lamp 10.
As shown in FIG. 2, the spectroscope 20 includes a grating 21 and a MEMS mirror 26.

The grating 21 diffracts the light generated by the infrared lamp 10 to divide the light for each wavelength.
The grating 21 of the present embodiment is a diffraction grating in which a large number of grooves (several hundreds to thousands of grooves per 1 mm) are formed. The light incident on the grating 21 is diffracted and dispersed for each wavelength, and the dispersed light is reflected at different reflection angles (diffraction angles) depending on the wavelength.
As shown in FIG. 1, the grating 21 is fixed at a predetermined position inside the case 121.

The MEMS mirror 26 reflects the light reflected by the grating 21 in a predetermined direction. The MEMS mirror 26 is manufactured by a so-called MEMS (Micro Electro Mechanical Systems) technology.
As shown in FIG. 1, the MEMS mirror 26 is fixed at a predetermined position inside the case 121.
As shown in FIG. 2, the MEMS mirror 26 has a base portion 26a and a rotating portion 26b.

  The base 26a is a flat plate-like member, and an opening 26c is formed at the center.

The rotation part 26b is a flat plate-like member, is disposed at a position accommodated in the opening 26c, and is rotatably connected to and supported by the base part 26a. The rotating part 26b rotates with respect to the base part 26a by elastically twisting the connecting part with the base part 26a.
As shown in FIG. 2, when no force is applied to the rotating portion 26b, the connecting portion between the rotating portion 26b and the base portion 26a is not elastically twisted, and the rotating portion 26b is a pair of plates of the base portion 26a. The surface is held in a posture (reference posture) in which the plate surface of the rotating portion 26b is parallel.
A thin film made of gold, aluminum, or the like is formed on one plate surface of the rotating portion 26 b, and the thin film forms a reflective surface of the MEMS mirror 26.

The MEMS mirror 26 of this embodiment is a so-called electromagnetic force type mirror.
A pair of permanent magnets are embedded in the base portion 26a so as to sandwich the opening portion 26c and eventually the rotating portion 26b. Accordingly, the rotating portion 26b is disposed in a magnetic field formed by the pair of permanent magnets.
In addition, a wiring capable of applying a voltage from the outside is formed in the rotating portion 26b.

When a voltage is applied to the wiring formed in the rotating part 26b, Lorentz force acts on the rotating part 26b arranged in a magnetic field formed by a pair of permanent magnets. As a result, the rotation part 26b rotates with respect to the base part 26a, and the angle of the reflective surface formed in the rotation part 26b is changed.
The magnitude of the Lorentz force acting on the rotating part 26b has a magnitude corresponding to the voltage value applied to the wiring formed on the rotating part 26b, and consequently the current value.
Therefore, by adjusting the voltage value (current value) applied to the wiring formed in the rotating portion 26b, the rotating angle of the rotating portion 26b and consequently the reflection angle of the MEMS mirror 26 can be adjusted. is there.

When the reflection angle of the MEMS mirror 26 changes, the angle at which the light reflected by the MEMS mirror 26 in a predetermined direction (in this embodiment, the direction toward the photodiode 30) is incident from the grating 21 changes.
Therefore, by adjusting the reflection angle of the MEMS mirror 26, the wavelength of light reflected by the MEMS mirror 26 in a predetermined direction can be adjusted.

Further, when the application of voltage to the wiring formed in the rotating portion 26b is stopped, the rotating portion 26b rotates to eliminate the elastic torsional deformation of the connecting portion with the base portion 26a and returns to the reference posture.
Therefore, by applying a voltage at a predetermined frequency to the wiring formed in the rotation unit 26b, the rotation unit 26b swings at the predetermined frequency, and the light reflected in the predetermined direction by the MEMS mirror 26 is reflected. Wavelength fluctuates periodically (light wavelength fluctuates periodically).
Hereinafter, the period in which the rotating portion 26b of the MEMS mirror 26 swings is referred to as “spectral period of the spectroscope 20”.

The MEMS mirror 26 of the present embodiment is a so-called electromagnetic force type mirror, but the MEMS mirror according to the present invention is not limited to this, and may be of other driving types (for example, electrostatic type, piezoelectric type, thermal strain type). You may rotate a rotation part with respect to a base.
The MEMS mirror according to the present invention can be achieved by a commercially available MEMS mirror.

The photodiode 30 is an embodiment of a light receiver according to the present invention, and detects the intensity of light whose wavelength has been varied by the spectrometer 20.
The photodiode 30 of the present embodiment is composed of a semiconductor element that detects the intensity of received light, and outputs (transmits) an electrical signal corresponding to the intensity of the received light.

1 and 2, the optical system of the THC measuring apparatus 100 forms an optical path Z from the infrared lamp 10 to the photodiode 30 through the spectroscope 20 and the gas container 40.
As shown in FIG. 1, the gas container 40 is disposed at a position sandwiched between the spectroscope 20 and the photodiode 30 in the optical path Z.
The light generated by the infrared lamp 10 passes through the entrance-side window member 42 and enters the body member 41 in a state where the wavelength is periodically changed by the spectrometer 20. The light that has entered the body member 41 passes through the object to be measured housed in the body member 41, and then passes through the exit-side window member 43 to the outside of the body member 41 (outside the gas container 40). Guided and received by the photodiode 30.

The first condenser lens 61 is an optical element that condenses (converges) the light generated by the infrared lamp 10.
As shown in FIG. 1, the first condenser lens 61 is fixed at a predetermined position inside the case 121.
As shown in FIG. 2, the first condenser lens 61 is disposed at a position sandwiched between the infrared lamp 10 and the spectroscope 20 in the optical path Z.

The collimating lens 62 is an optical element that irradiates the spectroscope 20 (more specifically, the grating 21) with the light collected by the first condenser lens 61 as parallel light.
As shown in FIG. 1, the collimating lens 62 is fixed at a predetermined position inside the case 121.
As shown in FIG. 2, the collimating lens 62 is sandwiched between the infrared lamp 10 and the spectroscope 20 in the optical path Z, and is disposed at a position downstream of the first condenser lens 61.
Further, the collimating lens 62 is disposed at a position downstream of the focal point Y (white circle in FIG. 2) of the light condensed by the first condenser lens 61 in the optical path Z.

The second condenser lens 63 is an optical element that condenses (converges) the light whose wavelength has been changed by the spectroscope 20 and irradiates (receives) light to the photodiode 30.
As shown in FIG. 2, the second condensing lens 63 is fitted in an opening formed in the case 121 at a position facing the inlet side window member 42 of the gas container 40, and from the inside of the light source side optical system unit 120 to the outside. Also serves as a window to irradiate light.

The optical chopper 50 includes a MEMS chopper member 51 and a slit member 56.
As shown in FIG. 1, the optical chopper 50 is fixed at a predetermined position inside the case 121.
As shown in FIG. 2, the optical chopper 50 is disposed at a position sandwiched between the infrared lamp 10 and the spectroscope 20 in the optical path Z, more specifically at a position sandwiched between the first condenser lens 61 and the collimating lens 62.

The MEMS chopper member 51 is manufactured by a so-called MEMS (Micro Electro Mechanical Systems) technique.
As shown in FIG. 2, the MEMS chopper member 51 has a base portion 51a and a rotating portion 51b.

  The base 51a is a flat plate member having a pair of plate surfaces, and an opening 51c penetrating the pair of plate surfaces of the base 51a is formed at the center of the base 51a.

The rotation part 51b is a flat plate-like member, is disposed at a position accommodated in the opening 51c, and is rotatably connected to and supported by the base 51a. The rotating part 51b rotates with respect to the base 51a by elastically twisting the connecting part with the base 51a.
As shown in FIG. 2, when no force is applied to the rotating portion 51b, the connecting portion of the rotating portion 51b and the base portion 51a is not elastically twisted, and the rotating portion 51b is a pair of plates of the base portion 51a. The surface is held in a posture (reference posture) in which the plate surface of the rotating portion 51b is parallel. As a result, the opening 51c is closed (closed) by the rotating portion 51b.

The MEMS chopper member 51 of this embodiment is a so-called electromagnetic force type actuator.
A pair of permanent magnets are embedded in the base 51a so as to sandwich the opening 51c, and thus the rotating part 51b. Therefore, the rotating part 51b is disposed in a magnetic field formed by the pair of permanent magnets.
In addition, a wiring capable of applying a voltage from the outside is formed in the rotating portion 51b.

The rotating part 51b rotates with respect to the base part 51a corresponding to the voltage application state.
That is, when a voltage is applied to the wiring formed in the rotating portion 51b, Lorentz force acts on the rotating portion 51b disposed in the magnetic field formed by the pair of permanent magnets. As a result, the rotating part 51b rotates with respect to the base part 51a, and the opening 51c (strictly, a part of the opening 51c) is opened.

Further, when the application of the voltage to the wiring formed in the rotating portion 51b is stopped, the rotating portion 51b rotates to eliminate the elastic twisting deformation of the connecting portion with the base 51a and returns to the reference posture.
Therefore, by applying a voltage at a predetermined frequency to the wiring formed in the rotating portion 51b, the rotating portion 51b swings at the predetermined frequency and opens and closes the opening 51c.

As shown by a solid line in FIG. 2, when the rotating unit 51 b is in the reference posture, the light collected by the first condenser lens 61 is blocked by the rotating unit 51 b and does not reach the photodiode 30. A state in which light is blocked by the light chopper 50 when the rotating unit 51b takes the reference posture is referred to as a “blocking state”.
As shown by a dotted line in FIG. 2, when the rotating part 51b is in a posture of rotating with respect to the base part 51a, the light collected by the first condenser lens 61 is not blocked by the rotating part 51b. It passes through the opening 51c and reaches the photodiode 30. A state in which light passes through the light chopper 50 when the rotating unit 51b is rotated with respect to the base 51a is referred to as a “passing state”.
Thus, the rotation part 51b of the MEMS chopper member 51 can be switched to either the “passing state” or the “cut-off state” by rotating.
Hereinafter, the cycle in which the rotating portion 51b of the MEMS chopper member 51 rotates (swings), more precisely, the cycle from the start of the passing state to the transition to the passing state through the transition to the blocking state is referred to as “optical chopper”. 50 chopping cycles.

The MEMS chopper member 51 of the present embodiment is a so-called electromagnetic force type actuator, but the MEMS chopper member according to the present invention is not limited to this, and other driving types (for example, electrostatic type, piezoelectric type, thermal strain type). ) May rotate the rotating portion relative to the base.
Further, a commercially available MEMS mirror or other MEMS actuator can be used as the MEMS chopper member according to the present invention.

The “chopping period of the optical chopper 50” is set to be shorter than the “spectral period of the spectrometer 20” (the chopping frequency of the optical chopper 50 is set to be higher than the spectral frequency of the spectrometer 20). )
When the MEMS chopper member 51 is configured using an existing MEMS mirror, the chopping cycle of the optical chopper 50 can be set to about 10 μsec to 100 μsec (the chopping frequency of the optical chopper 50 is set to about 10 kHz to 100 kHz). Is possible).
Therefore, it is possible to shorten the “spectral period of the spectroscope 20” within a range that does not become shorter than the chopping period of the optical chopper 50, which contributes to improvement of the high-speed response (real-time property) of the THC measurement apparatus 100. Here, the high-speed response means that it is possible to accurately detect the composition variation (in this embodiment, variation in hydrocarbon concentration) of the measurement target gas in a very short time.

As shown in FIG. 2, in the present embodiment, the opening 51c of the MEMS chopper member 51 is disposed at a position corresponding to the focal point Y (a position near the focal point Y).
With this configuration, the light generated by the infrared lamp 10 passes through the opening 51c in a state where the light is converged finely. "And" blocking state "can be switched, and the chopping cycle of the optical chopper 50 can be further shortened.
This chopping increases the light receiving intensity (depending on the frequency domain, the sensitivity of the light receiving element increases as the frequency increases), and thus the S / N ratio can be increased. Furthermore, when a lock-in amplifier is combined, it is possible to effectively remove noise components, and thus the S / N ratio can be further increased.

  In the present embodiment, the opening 51c is closed by the turning portion 51b when the turning portion 51b is in the reference posture. The term “closed” here means that the opening 51c is completely closed by the turning portion 51b. It does not indicate that it is sealed (there is no gap between the end surface of the opening 51c and the rotating portion 51b), but indicates that the light is covered to the extent that it cannot pass through the opening 51c.

The slit member 56 narrows the light generated by the infrared lamp 10 (excludes disturbance light from the optical path Z, thereby improving the wavelength resolution of the THC measurement apparatus 100).
The slit member 56 is a plate-like member having a pair of plate surfaces, and the slit member 56 is formed with a slit 56 a that is a groove penetrating the pair of plate surfaces of the slit member 56.

The slit member 56 is disposed at a position adjacent to the MEMS chopper member 51. In this embodiment, the slit member 56 is bonded to the rear plate surface of the MEMS chopper member 51 (the plate surface on the downstream side of the optical path Z among the pair of plate surfaces of the base portion 51a of the MEMS chopper member 51). It is fixed with.
Therefore, the MEMS chopper member 51 is disposed upstream of the slit member 56 in the light optical path Z (the slit member 56 is disposed downstream of the MEMS chopper member 51 in the light optical path Z).
This configuration has the following advantages. That is, if the MEMS chopper member is disposed downstream of the slit member in the optical path of light, a part of the light blocked (reflected) by the rotating portion of the MEMS chopper member is further reflected by the slit member. In some cases, the light becomes disturbance light, passes through the opening of the base portion of the MEMS chopper member, reaches the spectroscope, and eventually the light receiver, and decreases the detection accuracy of the light intensity by the light receiver.
Therefore, when the MEMS chopper member is arranged downstream of the slit member in the optical path of the light, the shape, surface color, arrangement, etc. of the slit member are separately devised in order to eliminate the influence of such disturbance light. Although it is necessary, when the slit member 56 is arranged on the downstream side of the MEMS chopper member 51 in the optical path Z of the light as in this embodiment, the light blocked (reflected) by the rotating portion 51b is caused by the slit member 56. Since it is not reflected again, it is possible to easily eliminate the influence of disturbance light, and it is possible to improve the wavelength resolution of the THC measurement apparatus 100.

The slit 56a of the slit member 56 fixed to the MEMS chopper member 51 is disposed at a position corresponding to the focal point Y (a position near the focal point Y).
With this configuration, the light generated by the infrared lamp 10 passes through the slit 56a in a state where the light is converged finely, and the slit 56a is made as thin as possible while ensuring the amount of light passing through the slit 56a. It is possible to eliminate the influence of disturbance light, and to improve both the S / N ratio of the THC measurement apparatus 100 and the wavelength resolution.

When the MEMS chopper member 51 is configured by diverting an existing MEMS mirror, the MEMS chopper member 51 can be suppressed to a size of, for example, about 20 mm long × 30 mm wide × 5 mm thick. Further, the thickness of the slit member 56 can be suppressed to about several mm.
Accordingly, the size of the MEMS chopper member 51 and the slit member 56, that is, the optical chopper 50 can be made compact as a whole, and the optical chopper 50 can be downsized.
Further, by reducing the size of the optical chopper 50, it is possible to reduce the size of the entire optical system of the THC measuring apparatus 100. Downsizing the THC measuring device 100 is particularly effective when the exhaust gas of a running vehicle is analyzed with the THC measuring device 100 attached to the vehicle.

Hereinafter, a control system of the THC measurement apparatus 100 will be described.
As shown in FIG. 1, the control system of the THC measurement device 100 is configured by a chopper / spectrometer control device 70, a lock-in amplifier 80, and a data processing device 190.

The chopper / spectrometer control device 70 is a device that controls the operation of the optical chopper 50 and the MEMS mirror 26 of the spectroscope 20.
The chopper / spectrometer control device 70 is connected to the optical chopper 50, more precisely, to the MEMS chopper member 51, and has a predetermined period (period corresponding to the chopping period) in the wiring formed in the rotating part 51b of the MEMS chopper member 51. It is possible to apply a voltage of
The chopper / spectrometer control device 70 is connected to the MEMS mirror 26, and can apply a voltage having a predetermined period (a period corresponding to the spectroscopic period) to the wiring formed in the rotating portion 26b of the MEMS mirror 26. .
The chopper / spectrometer control device 70 is an oscillation circuit for MEMS mirror drive control, and can be achieved by a general purpose device as long as the frequency can be set.

The lock-in amplifier 80 removes a noise component from an electrical signal (measurement signal) corresponding to the intensity of light received by the photodiode 30.
The lock-in amplifier 80 is connected to the photodiode 30 and can receive a measurement signal from the photodiode 30.
The lock-in amplifier 80 is connected to the chopper / spectrometer control device 70, and a signal (reference signal) indicating the timing of the voltage applied to the wiring formed in the rotating part 51 b of the MEMS chopper member 51 by the chopper / spectrometer control device 70. ), And a signal (spectral period signal) indicating the timing of the voltage applied to the wiring formed in the rotating portion 26b of the MEMS mirror 26 can be received from the chopper / spectrometer control device 70.
The lock-in amplifier 80 generates a measurement signal (corrected measurement signal) from which noise components have been removed based on the measurement signal and the reference signal.
The lock-in amplifier 80 is achieved by a known lock-in amplifier or a circuit that exhibits an equivalent function.

The data processing device 190 is an embodiment of the concentration calculation device according to the present invention.
Based on the intensity of light received by the photodiode 30, the data processing device 190 includes (a) a group consisting of alkane and alkene, and (b) a group consisting of aromatic hydrocarbons among the hydrocarbons contained in the measurement target gas 1. A concentration sum of hydrocarbons belonging to the group and (c) the group consisting of alkynes is calculated for each group.
The data processing device 190 includes a processing unit 191, an input unit 192, and a display unit 193.

  The processing unit 191 can store various programs and the like, expand these programs and the like, perform predetermined calculations according to these programs and the like, and store the calculation results and the like.

The processing unit 191 may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.
Although the processing unit 191 of this embodiment is a dedicated product, it can also be achieved by storing the above-described program in a commercially available personal computer or workstation.

  The processing unit 191 is connected to the lock-in amplifier 80 and can acquire (receive) the corrected measurement signal and the spectral period signal from the lock-in amplifier 80.

  The processing unit 191 can store information used for various calculations performed in the processing unit 191, calculation results, and the like.

The processing unit 191 stores in advance a spectrum of a reference gas (hereinafter referred to as a reference gas), that is, a reference spectrum A ₀ (λ) shown in FIG.

The “reference gas” is a gas that is known in advance not to absorb light in the three absorption wavelength bands of hydrocarbons contained in the measurement target gas. A specific example of the reference gas is nitrogen gas.
The “reference spectrum” indicates the relationship between the wavelength and the light intensity when the reference gas is irradiated with light, and is expressed as a function of the wavelength. In the following description, when the relationship between wavelength and light intensity is shown, the horizontal axis represents wavelength and the vertical axis represents light intensity.
In the present embodiment, the wavelength band of the spectrum of the reference spectra A ₀ (λ) is set to a range of 2000 cm ^-1 or 4000 cm ^-1 or less in terms of wavenumber.
Thus, the shortest wavelength λmin of the reference spectra A ₀ (λ) is the wavelength at which 4000 cm ^-1 in terms of wavenumber, the longest wavelength λmax of reference spectra A ₀ (λ) is the 2000 cm ^-1 in terms of wavenumber Is the wavelength.

As shown in FIG. 3, the reference spectrum A ₀ (λ) of this embodiment belongs to (a) a wavelength band absorbed by hydrocarbons belonging to a group consisting of alkanes and alkenes, and (b) belongs to a group consisting of aromatic hydrocarbons. All of the wavelength bands absorbed by hydrocarbons and (c) the wavelength bands absorbed by hydrocarbons belonging to the group consisting of alkynes are included.
Note that the wavelength band indicated by (d) in FIG. 3 is a wavelength band not corresponding to any of the above (a) to (c), that is, a hydrocarbon or an aromatic hydrocarbon belonging to the group consisting of alkane and alkene. It is a wavelength band in which neither hydrocarbons belonging to the group nor hydrocarbons belonging to the group consisting of alkynes are absorbed. Hereinafter, the wavelength band indicated by (d) is referred to as “the non-absorption wavelength band of the measurement target gas 1”.

The processing unit 191 calculates and stores the first corrected reference spectrum A ₁ (λ) shown in FIG. 4 in advance.
The “first corrected reference spectrum” is calculated by subtracting the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the reference spectrum from the reference spectrum, and is expressed as a function of wavelength. If the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the reference spectrum are the same, subtract either the light intensity at the shortest wavelength point or the light intensity at the longest wavelength point in the reference spectrum from the reference spectrum. May be.
In the present embodiment, the light intensity A ₀ (λmax) of the longest wavelength point A ₀₂ (white square in FIG. 3) of the reference spectrum A ₀ (λ) shown in FIG. 3 is the shortest wavelength point A ₀₁ (black in FIG. 3). is smaller than the light intensity a ₀ square) ([lambda] min), by subtracting the light intensity a ₀ (.lambda.max) from reference spectra a ₀ (lambda), the first correction reference spectrum a ₁ shown in FIG. 4 (lambda) It is calculated (A ₁ (λ) = A ₀ (λ) −A ₀ (λmax)).

As shown in FIG. 4, the value of the coordinate A ₁ (λmax) on the vertical axis of the longest wavelength point A ₁₂ (white square in FIG. 4) in the first corrected reference spectrum A ₁ (λ) is zero (A ₁ ( λmax) = 0), the longest wavelength point A ₁₂ is located on the horizontal axis.

The processing unit 191 calculates and stores the second corrected reference spectrum A ₂ (λ) shown in FIG. 5 in advance.
The “second corrected reference spectrum” is calculated by adding a constant to the first corrected reference spectrum and is expressed as a function of wavelength.
In this embodiment, the second corrected reference spectrum A ₂ (λ) is calculated by adding a constant C to the first corrected reference spectrum A ₁ (λ) (A ₂ (λ) = A ₁ (λ) + C. ).
As shown in FIG. 5, the value of the coordinate A ₂ (λmax) on the vertical axis of the longest wavelength point A ₂₂ (white square in FIG. 5) in the second corrected reference spectrum A ₂ (λ) is C (A ₂ ( λmax)
= C).
The constant C is added for the sake of convenience in order to avoid the case where logarithmic calculation included in the calculation based on Equation 1 described later becomes impossible. Therefore, the value of the constant C is usually a positive value. However, if the logarithmic calculation is not disabled without adding the constant C, the calculation for adding the constant C to the first corrected reference spectrum and calculating the second corrected reference spectrum is omitted, or the value of the constant C is set to zero. It is also possible.

Based on the corrected measurement signal and the spectral period signal acquired from the lock-in amplifier 80, the processing unit 191 calculates “absorption spectrum B ₀ (λ) of the measurement target gas 1” shown in FIG.
The “absorption spectrum of the measurement target gas” indicates the relationship between the wavelength and the light intensity when the measurement target gas is irradiated with light, and is expressed as a function of the wavelength.

More specifically, the processing unit 191 compares the corrected measurement signal and the spectral period signal, and sequentially performs an operation of specifying which wavelength band the intensity of the acquired corrected measurement signal indicates light, thereby performing measurement. An absorption spectrum B ₀ (λ) of the target gas 1 is calculated.
The shortest wavelength and the longest wavelength of the absorption spectrum B ₀ (λ) shown in FIG. 6 respectively match the shortest wavelength and the longest wavelength of the reference spectrum A ₀ (λ) shown in FIG.

The absorption spectrum B ₀ (λ) of the measurement target gas 1 indicated by the thick solid line in FIG. 6 is compared with the reference spectrum A ₀ (λ) indicated by the thick solid line in FIG. 3 and indicated by the two-dot chain line in FIG. The light intensity is low overall.
This is because the optical system (for example, the first condenser lens 61, the collimator lens 62, the second condenser lens 63) of the THC measuring apparatus 100, the inlet side window member 42 and the outlet side window member 43 provided in the gas container 40 are used. Due to disturbance factors such as contamination.
Further, when the gas container 40 rises in temperature due to heat conduction from the measurement target gas 1 and infrared light is emitted from the gas container 40, a disturbance factor further overlaps with the absorption spectrum of the measurement target gas 1. .
Therefore, usually, (not match the coordinates of the vertical axis) do not overlap the shortest wavelength point B ₀₁ and the reference spectrum A ₀ shortest wavelength point A ₀₁ in (lambda) of the absorption spectrum B ₀ (lambda), the absorption spectrum does not overlap the longest wavelength point a ₀₂ of B ₀ (lambda) maximum wavelength point B ₀₂ and the reference spectra a ₀ of (lambda) (the ordinate does not match).

As shown in FIG. 6, the absorption spectrum B ₀ (λ) of the measurement target gas 1 is (a) a wavelength band absorbed by hydrocarbons belonging to the group consisting of alkanes and alkenes, and (b) a group consisting of aromatic hydrocarbons. In the wavelength band that the hydrocarbons that belong to, and the wavelength band that the hydrocarbons that belong to the group consisting of (c) alkynes absorb, the light intensity decreases (the corresponding wavelength band part is convex downward) )
This is because, when the light generated by the infrared lamp 10 passes through the gas 1 to be measured, (a) the wavelength band absorbed by the hydrocarbons belonging to the group consisting of alkane and alkene, and (b) the fragrance. The hydrocarbons contained in the measurement target gas 1 have components corresponding to the wavelength band absorbed by hydrocarbons belonging to the group consisting of group hydrocarbons and (c) the wavelength band absorbed by hydrocarbons belonging to the group consisting of alkynes, respectively. By being absorbed into.

The processing unit 191 calculates the “first corrected absorption spectrum B ₁ (λ) of the measurement target gas 1” illustrated in FIG. 7 based on the absorption spectrum B ₀ (λ) of the measurement target gas 1.
The “first corrected absorption spectrum of the measurement target gas” is calculated by subtracting the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the absorption spectrum from the absorption spectrum of the measurement target gas. , Expressed as a function of wavelength. If the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the absorption spectrum are the same, the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the absorption spectrum are determined from the absorption spectrum of the gas to be measured. Either of these may be drawn.
In the present embodiment, the light intensity B ₀ (.lambda.max) shortest wavelength point B ₀₁ is (FIG longest wavelength point B ₀₂ (white circles in Fig. 6) of the absorption spectrum B ₀ of the measuring object gas 1 (lambda) shown in FIG. 6 7 is smaller than the light intensity B ₀ (λmin) of the measurement target gas 1, the first corrected absorption shown in FIG. 7 is obtained by subtracting the light intensity B ₀ (λmax) from the absorption spectrum B ₀ (λ) of the measurement target gas 1. The spectrum B ₁ (λ) is calculated (B ₁ (λ) = B ₀ (λ) −B ₀ (λmax)).

As shown in FIG. 7, the value of the coordinate B ₁ (λmax) on the vertical axis of the longest wavelength point B ₁₂ (white circle in FIG. 7) in the first corrected absorption spectrum B ₁ (λ) is zero (B ₁ (λmax ) = 0), the longest wavelength point B ₁₂ is located on the horizontal axis.
Further, the longest wavelength point B ₁₂ (white circle in FIG. 7) in the first corrected absorption spectrum B ₁ (λ) and the longest wavelength point A ₁₂ (in FIG. 4 and FIG. 7) in the first corrected reference spectrum A ₁ (λ). The white squares overlap (the coordinates of the vertical axis match).

The processing unit 191 calculates the second corrected absorption spectrum B ₂ (λ) shown in FIG. 8 based on the first corrected reference spectrum A ₁ (λ) and the first corrected absorption spectrum B ₁ (λ).
The “second corrected absorption spectrum” is “the light intensity (α) of the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the first corrected reference spectrum is Calculated by multiplying the first corrected absorption spectrum by the value obtained by dividing the light intensity and the light intensity at the longest wavelength point by the larger light intensity (β) (= α / β), and is expressed as a function of wavelength. .
The light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the first corrected reference spectrum are the same, or the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the first corrected absorption spectrum are the same. In this case, the value of the above (α / β) is set to 1 and the first corrected absorption spectrum is multiplied (substantially, the first corrected absorption spectrum is directly used as the second corrected absorption spectrum).
In this embodiment, the light intensity A ₁ (black square in FIGS. 4 and 7) of the shortest wavelength point A ₁₁ (black square in FIGS. 4 and 7) of the first corrected reference spectrum A ₁ (λ) of the measurement target gas 1 shown in FIGS. λmin) is larger than the light intensity A ₁ (λmax) of the longest wavelength point A ₁₂ (white square in FIGS. 4 and 7), and the first corrected absorption spectrum B ₁ (λ since the shortest wavelength point B ₁₁ of) (light intensity of black circle) in FIG. 7 B ₁ ([lambda] min) is the longest wavelength point B ₁₂ (greater than the light intensity of the white circle) in FIG. 7 B ₁ (.lambda.max), light intensity by multiplying a ₁ a value obtained by dividing the light intensity B ₁ ([lambda] min) and ([lambda] min) to the first correction absorption spectrum B ₁ (λ), the second correction absorption spectrum B ₂ (lambda) is calculated as shown in FIG. 8 (B ₂ (λ) = {A ₁ (λmin) / B ₁ (λmin)} × B ₁ (λ)).

As shown in FIG. 8, the value of the coordinate B ₂ (λmax) on the vertical axis of the longest wavelength point B ₂₂ (white circle in FIG. 8) in the second corrected absorption spectrum B ₂ (λ) is zero (B ₂ (λmax ) = 0), the longest wavelength point B ₂₂ is located on the horizontal axis.
Further, the longest wavelength point B ₂₂ (white circle in FIG. 8) in the second corrected absorption spectrum B ₂ (λ) and the longest wavelength point A ₁₂ in the first corrected reference spectrum A ₁ (λ) (in FIGS. 4 and 8). The white squares overlap (the coordinates of the vertical axes coincide), and the shortest wavelength point B ₂₁ (black circle in FIG. 8) and the first corrected reference spectrum A ₁ (λ) in the second corrected absorption spectrum B ₂ (λ). The shortest wavelength point A ₁₁ (black square in FIGS. 4 and 8) overlaps (the coordinates of the vertical axis coincide).

The processing unit 191 calculates a third corrected absorption spectrum B ₃ (λ) shown in FIG. 9 based on the second corrected absorption spectrum B ₂ (λ).
The “third corrected absorption spectrum” is a value obtained by adding a constant to the second corrected absorption spectrum, and is expressed as a function of wavelength. Here, the value of the constant added to the second corrected absorption spectrum is the same as the value of the constant added to the first corrected reference spectrum when calculating the second corrected reference spectrum.
In the present embodiment, the third corrected absorption spectrum B ₃ (λ) is calculated by adding a constant C to the second corrected absorption spectrum B ₂ (λ) (B ₃ (λ) = B ₂ (λ) + C. ).
The constant C is added for the sake of convenience in order to avoid the case where logarithmic calculation included in the calculation based on Equation 1 described later becomes impossible. Therefore, the value of the constant C is usually a positive value.
However, if the logarithmic operation is not disabled without adding the constant C, the calculation for adding the constant C to the second corrected absorption spectrum and calculating the third corrected absorption spectrum is omitted, or the value of the constant C is set to zero. It is also possible.

As shown in FIG. 9, the value of the coordinate B ₃ (λmax) on the vertical axis of the longest wavelength point B ₃₂ (white circle in FIG. 9) in the third corrected absorption spectrum B ₃ (λ) is C (B ₃ (λmax ) = C).
Further, the longest wavelength point B ₃₂ (white circle in FIG. 9) in the third corrected absorption spectrum B ₃ (λ) and the longest wavelength point A ₂₂ in the second corrected reference spectrum A ₂ (λ) (in FIGS. 5 and 9). The white squares overlap (the coordinates of the vertical axes coincide), and the shortest wavelength point B ₃₁ (black circle in FIG. 9) and the second corrected reference spectrum A ₂ (λ) in the third corrected absorption spectrum B ₃ (λ) The shortest wavelength point A ₂₁ (black square in FIG. 5 and FIG. 9) overlaps (the coordinates of the vertical axis coincide).

As described above, a series of processing (calculation) performed by the processing unit 191 on the reference spectrum A ₀ (λ) and the absorption spectrum B ₀ (λ) is substantially the shortest wavelength point of the reference spectrum A ₀ (λ). a ₀₁ the shortest wavelength point B ₀₁ and the overlap of the absorption spectrum B ₀ (lambda), and reference spectra a ₀ the longest wavelength point a ₀₂ in (lambda) and the longest wavelength point B ₀₂ of the absorption spectrum B ₀ (lambda) It is equivalent to performing correction so that.

As shown in FIG. 9, when the second corrected reference spectrum A ₂ (λ) and the third corrected absorption spectrum B ₃ (λ) are compared, “(a) Wavelength band absorbed by hydrocarbons belonging to the group consisting of alkane and alkene” , (B) a wavelength band absorbed by a hydrocarbon belonging to the group consisting of aromatic hydrocarbons, and (c) a wavelength band excluding a wavelength band absorbed by the hydrocarbon belonging to the group consisting of alkynes, that is, “(c) The light intensities in the wavelength band shorter than the wavelength band of (1), the wavelength band longer than the wavelength band of (a) and the wavelength band of (d) ”are in good agreement, and the disturbance factor is eliminated.

Based on the second corrected reference spectrum A ₂ (λ), the third corrected absorption spectrum B ₃ (λ), and the following Equation 1, the processing unit 191 selects (a) alkane among the hydrocarbons contained in the measurement target gas 1. And the amount of light absorbed in the wavelength band absorbed by each of the group consisting of alkene, (b) group consisting of aromatic hydrocarbons, and (c) group consisting of alkynes.

Equation 1 is a calculation formula based on Lambert-Beer's law.
In Equation 1, n = 1 indicates “a group composed of alkane and alkene”, n = 2 refers to “a group composed of aromatic hydrocarbons”, and n = 3 refers to “a group composed of alkynes”.
In Equation 1, X ₁ is “absorbance of hydrocarbons belonging to the group consisting of alkanes and alkenes (light absorption amount)”, and X ₂ is “absorbance of hydrocarbons belonging to the group consisting of aromatic hydrocarbons (light absorption amount). ) ”, X ₃ refers to“ absorbance (absorption amount of light) of hydrocarbons belonging to the group consisting of alkynes ”.
In Equation 1, “I ₁ ” is the light intensity of “absorption wavelength band of hydrocarbon belonging to the group consisting of alkane and alkene” in the third corrected absorption spectrum, and “I ₂ ” is “aromatic carbonization in the third corrected absorption spectrum. The light intensity of the “absorption wavelength band of hydrocarbons belonging to the group consisting of hydrogen”, and “I ₃ ” refer to the light intensity of the “absorption wavelength band of hydrocarbons belonging to the group consisting of alkynes” in the third corrected absorption spectrum.
In Equation 1, "(I _{1) 0"} is the light intensity of the "absorption wavelength range of hydrocarbons belonging to the group consisting of alkanes and alkenes" in the second correction reference spectrum, "(I _{2) 0"} and the second correction reference The light intensity of the “absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons” in the spectrum, “(I ₃ ) ₀ ” is the absorption wavelength band of hydrocarbons belonging to the group consisting of alkynes in the second corrected reference spectrum "Indicates the light intensity.

The processing unit 191 calculates “the sum of the concentrations of hydrocarbons belonging to the group consisting of alkane and alkene” based on “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkane and alkene” calculated based on Equation 1. Based on the “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”, the “sum of the concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons” is calculated, and “from alkyne Based on the “absorbance in the absorption wavelength band of hydrocarbons belonging to a certain group”, “the sum of the concentrations of hydrocarbons belonging to the group consisting of alkynes” is calculated.
Specifically, the processing unit 191 includes the measurement target gas 1 as a product of the coefficient K1 stored in the processing unit 191 in advance and “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkane and alkene”. The “sum of the concentrations of hydrocarbons belonging to the group consisting of alkanes and alkenes” is calculated.
Similarly, the processing unit 191 is included in the measurement target gas 1 as the product of the coefficient K2 stored in advance in the processing unit 191 and “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”. The “sum of the concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons” is calculated.
Similarly, the processing unit 191 calculates “from alkyne as a product of the coefficient K3 stored in advance in the processing unit 191 and“ absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkyne ”contained in the measurement target gas 1. The sum of the concentrations of hydrocarbons belonging to a certain group is calculated.

  The processing unit 191 calculates the above-mentioned “sum of concentrations of hydrocarbons belonging to the group consisting of alkane and alkene”, “sum of concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”, and “group consisting of alkynes” As the sum of the “sum of the concentrations of hydrocarbons belonging to”, “the total hydrocarbon concentration of the gas 1 to be measured” is calculated.

  The processing unit 191 calculates the “sum of the concentration of hydrocarbons belonging to the group consisting of alkanes and alkenes”, “the sum of the concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”, and “belonging to the group consisting of alkynes” “Sum of hydrocarbon concentrations” and “total hydrocarbon concentration of measurement target gas 1” are stored as appropriate.

The initial values of the coefficient K1, the coefficient K2, and the coefficient K3 are obtained by measuring a gas whose hydrocarbon composition is known in advance by the FID-GC or the like using the THC measuring device 100, and the group consisting of alkane and alkene. Calculation result of "absorbance in the absorption wavelength band of hydrocarbons belonging to", calculation result of "absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons", and absorption of hydrocarbons belonging to the group consisting of alkynes It is experimentally determined based on the calculation result of “absorbance in wavelength band”.
In the case of this embodiment, the sum of the concentrations of hydrocarbons belonging to each group calculated by the processing unit 191 and the total hydrocarbon concentration are calculated in the form of methane equivalent concentration values (ppmC). However, the calculation may be performed in a form such as a volume ratio.

The input unit 192 is connected to the processing unit 191 and inputs various information / instructions related to the measurement of the hydrocarbon concentration by the THC measuring apparatus 100 to the processing unit 191.
The processing unit 191 of the present embodiment is a dedicated product, but the same effect can be achieved by using a commercially available keyboard, mouse, pointing device, button, switch, or the like.

The display unit 193 displays the input content from the input unit 192 to the processing unit 191, the calculation result (measurement result of hydrocarbon concentration) by the processing unit 191, and the like.
The display unit 193 of the present embodiment is a dedicated product, but the same effect can be achieved even if a commercially available monitor, liquid crystal display, or the like is used.

In the present embodiment, the gas container 40 is disposed at a position sandwiched between the spectroscope 20 and the photodiode 30 in the optical path Z formed by the infrared lamp 10, the spectroscope 20 and the photodiode 30. The hydrocarbon concentration according to the present invention The measuring device is not limited to this.
Another embodiment of the hydrocarbon concentration measuring apparatus according to the present invention includes a configuration in which a gas container is disposed at a position sandwiched between a light source and a spectroscope.

As described above, the THC measuring apparatus 100 is
An infrared lamp 10 for generating light;
A spectroscope 20 for periodically changing the wavelength of light generated by the infrared lamp 10, and
A photodiode 30 for detecting the intensity of light whose wavelength has been varied by the spectroscope 20;
A gas container 40 which is disposed at a position sandwiched between the spectroscope 20 and the photodiode 30 in an optical path Z formed by the infrared lamp 10, the spectroscope 20 and the photodiode 30, can accommodate the measurement target gas 1 and can transmit light. When,
References including wavelength bands absorbed by (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes among the hydrocarbons contained in measurement target gas 1 spectrum a ₀ reference spectra from (λ) a ₀ (λ) light intensity a ₀ of the shortest wavelength point a ₀₁ in ([lambda] min) and smaller light intensity of the light intensity a ₀ of the longest wavelength points a ₀₂ (λmax) ( In this embodiment, a second corrected reference spectrum A ₂ (λ) obtained by adding a constant C to the first corrected reference spectrum A ₁ (λ) calculated by subtracting A ₀ (λmax)) is stored in advance. based on the intensity of the detected light to calculate the absorption spectrum B ₀ of the measuring object gas 1 (lambda) due to the diode 30, absorption from the absorption spectrum B ₀ (lambda) The smaller the light intensity (the embodiment of the spectrum B ₀ intensity B ₀ of the shortest wavelength point B ₀₁ in (lambda) ([lambda] min) and the light intensity B ₀ of the longest wavelength point B ₀₂ (.lambda.max), B ₀ ( The first corrected absorption spectrum B ₁ (λ) is calculated by subtracting λmax)), and the light intensity A ₁ (λmin) and the longest wavelength point A of the shortest wavelength point A ₁₁ in the first corrected reference spectrum A ₁ (λ) are calculated. _{Of the 12} light intensities A ₁ (λmax), the larger light intensity (A ₁ (λmin) in this embodiment) is the light intensity B _{1 at the} shortest wavelength point B ₁₁ in the first corrected absorption spectrum B ₁ (λ). (Λmin) and the light intensity B ₁ (λmax) of the longest wavelength point B ₁₂ divided by the larger light intensity (B ₁ (λmin) in the present embodiment) is the first corrected absorption spectrum B ₁ (λ ) Torr B calculates ₂ (lambda), the second correction absorption spectrum B ₂ (lambda) to calculate a third corrected absorption spectrum B ₃ (lambda) by adding constants C, the second correction reference spectra A ₂ (lambda ), Among the hydrocarbons contained in the measurement target gas 1 based on the third corrected absorption spectrum B ₃ (λ) and Equation 1, (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, (C) Calculate the amount of light absorption (X ₁ , X ₂ and X ₃ ) in the wavelength band that each of the groups consisting of alkynes absorbs, and based on the calculated amount of light absorption corresponding to each group A data processing device 190 (more precisely, a processing unit 191) for calculating the concentration of hydrocarbons belonging to the group;
It comprises.
By configuring in this way, the THC measurement device 100 is capable of causing disturbance factors (for example, the optical system (lens or the like) of the THC measurement device 100) or the inlet side window member 42 and the outlet provided in the gas container 40. Gawamado member 43 is dirty, or the like gas container 40 is infrared light is radiated from the material constituting the temperature rising gas container 40 (metal or the like) by heat conduction from the measurement target gas 1) absorption spectrum B ₀ It is possible to eliminate the influence on (λ), and consequently the concentration of hydrocarbons contained in the measurement target gas 1 can be measured with high accuracy.

Below, 1st embodiment of the hydrocarbon concentration measuring method which concerns on this invention is described using FIG.
The first embodiment of the hydrocarbon concentration measuring method according to the present invention is a method for measuring the sum of the concentrations of hydrocarbons contained in the gas 1 to be measured using the THC measuring device 100.
As shown in FIG. 10, the first embodiment of the hydrocarbon concentration measuring method according to the present invention includes a detection step S1100, an absorption spectrum calculation step S1200, a first corrected absorption spectrum calculation step S1300, a second corrected absorption spectrum calculation step S1400, a first step. Three corrected absorption spectrum calculation steps S1500, a light absorption amount calculation step S1600, and a concentration calculation step S1700 are provided.

The detection step S1100 is a step in which the photodiode 30 detects the intensity of light generated by the infrared lamp 10 and transmitted through the measurement target gas 1 accommodated in the gas container 40.
In the present embodiment, the detection step S1100 is repeatedly performed at a predetermined cycle (spectral cycle of the spectrometer 20).

In the absorption spectrum calculation step S1200, the data processor 190 (more precisely, the processing unit 191) calculates the absorption spectrum B ₀ (λ) of the measurement target gas 1 based on the light intensity detected by the photodiode 30. It is a process to do.
When the absorption spectrum calculation step S1200 is completed, the process proceeds to the first corrected absorption spectrum calculation step S1300.

First correcting absorption spectrum calculating step S1300, the data processing device 190 (more precisely, the processing unit 191) the light intensity of the absorption spectrum B ₀ (lambda) from the absorption spectrum B ₀ (lambda) the shortest wavelength point B ₀₁ in By subtracting the smaller light intensity (B ₀ (λmax) in this embodiment) from B ₀ (λmin) and the light intensity B ₀ (λmax) of the longest wavelength point B ₀₂ , the first corrected absorption spectrum B ₁ ( This is a step of calculating λ).
If 1st correction | amendment absorption spectrum calculation process S1300 is complete | finished, it will transfer to 2nd correction | amendment absorption spectrum calculation process S1400.

In the second corrected absorption spectrum calculation step S1400, the data processor 190 (more precisely, the processing unit 191) causes the light intensity A ₁ (λmin) at the shortest wavelength point A ₁₁ in the first corrected reference spectrum A ₁ (λ). The light intensity (A ₁ (λmin) in this embodiment) of the light intensity A ₁ (λmax) of the longest wavelength point A ₁₂ is set to the shortest wavelength point B ₁₁ in the first corrected absorption spectrum B ₁ (λ). The first corrected absorption is obtained by dividing the light intensity B ₁ (λmin) and the light intensity B ₁ (λmax) of the longest wavelength point B _{12 by} the larger light intensity (B ₁ (λmin) in this embodiment). This is a step of calculating the second corrected absorption spectrum B ₂ (λ) by multiplying the spectrum B ₁ (λ).
If 2nd correction | amendment absorption spectrum calculation process S1400 is complete | finished, it will transfer to 3rd correction | amendment absorption spectrum calculation process S1500.

In the third corrected absorption spectrum calculation step S1500, the data processing device 190 (more precisely, the processing unit 191) adds a constant C to the second corrected absorption spectrum B ₂ (λ), thereby allowing the third corrected absorption spectrum B _3. This is a step of calculating (λ).
When the third corrected absorption spectrum calculating step S1500 is completed, the process proceeds to the light absorption amount calculating step S1600.

In the light absorption amount calculating step S1600, the data processing device 190 (more precisely, the processing unit 191) is based on the second corrected reference spectrum A ₂ (λ), the third corrected absorption spectrum B ₃ (λ), and Equation 1. Among the hydrocarbons contained in the gas 1 to be measured, light in the wavelength band absorbed by each of (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. Is the step of calculating the amount of absorption (in this embodiment, X ₁ , X ₂ and X ₃ ).
When the light absorption amount calculating step S1600 is completed, the process proceeds to the concentration calculating step S1700.

In the concentration calculation step S1700, the data processing device 190 (more precisely, the processing unit 191) has (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. This is a step of calculating the concentration of the hydrocarbons belonging to each group based on the amount of light absorbed by each of these (in this embodiment, X ₁ , X ₂ and X ₃ ).

As described above, the first embodiment of the hydrocarbon concentration measuring method according to the present invention is:
An infrared lamp 10 for generating light;
A spectroscope 20 for periodically changing the wavelength of light generated by the infrared lamp 10, and
A photodiode 30 for detecting the intensity of light whose wavelength has been varied by the spectroscope 20;
A gas container 40 which is disposed at a position sandwiched between the spectroscope 20 and the photodiode 30 in an optical path Z formed by the infrared lamp 10, the spectroscope 20 and the photodiode 30, can accommodate the measurement target gas 1 and can transmit light. When,
References including wavelength bands absorbed by (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes among the hydrocarbons contained in measurement target gas 1 spectrum a ₀ reference spectra from (λ) a ₀ (λ) light intensity a ₀ of the shortest wavelength point a ₀₁ in ([lambda] min) and smaller light intensity of the light intensity a ₀ of the longest wavelength points a ₀₂ (λmax) ( In the present embodiment, a second corrected reference spectrum A ₂ (λ) obtained by adding a constant C to the first corrected reference spectrum A ₁ (λ) calculated by subtracting A ₀ (λmax)) is stored in advance. A data processor 190 that calculates the concentration of hydrocarbons contained in the measurement target gas 1 based on the intensity of light detected by the photodiode 30. ,
A method for measuring the concentration of hydrocarbons contained in the gas 1 to be measured using a THC measuring device 100 comprising:
Detection step S1100;
Absorption spectrum calculation step S1200,
A first corrected absorption spectrum calculating step S1300;
A second corrected absorption spectrum calculating step S1400;
Third corrected absorption spectrum calculation step S1500,
A light absorption amount calculating step S1600;
Concentration calculation step S1700;
It comprises.
By configuring in this way, disturbance factors that change from moment to moment (for example, the optical system (lens or the like) of the THC measuring device 100) or the inlet side window member 42 and the outlet side window member 43 provided in the gas container 40 become dirty. The effect that the temperature of the gas container 40 rises due to heat conduction from the measurement target gas 1 and infrared light is emitted from the material (metal, etc.) constituting the gas container 40) affects the absorption spectrum B ₀ (λ). Therefore, the concentration of hydrocarbons contained in the measurement target gas 1 can be measured with high accuracy.

  Hereinafter, a THC measurement device 200 that is a second embodiment of the hydrocarbon concentration measurement device according to the present invention will be described with reference to FIGS. 1 and 11 to 17.

A THC measurement device 200 shown in FIG. 1 is a device that measures the concentration sum of hydrocarbons contained in the measurement target gas 1.
The THC measurement apparatus 200 includes a frame 110, a light source side optical system unit 120, a gas container 40, a photodiode 30, a chopper / spectrometer control device 70, a lock-in amplifier 80, and a data processing device 290.

  Among the members constituting the THC measurement device 200, the frame 110, the light source side optical system unit 120, the gas container 40, the photodiode 30, the chopper / spectrometer control device 70, and the lock-in amplifier 80 constitute the THC measurement device 100. Since it is substantially the same as a member, description is abbreviate | omitted.

The data processing device 290 is an embodiment of the concentration calculation device according to the present invention.
Based on the intensity of light received by the photodiode 30, the data processing device 290 includes (a) a group consisting of alkanes and alkenes, and (b) an aromatic hydrocarbon among the hydrocarbons contained in the measurement target gas 1. A concentration sum of hydrocarbons belonging to the group and (c) the group consisting of alkynes is calculated for each group.
The data processing device 290 includes a processing unit 291, an input unit 292, and a display unit 293.
The hardware configuration of the processing unit 291, the input unit 292, and the display unit 293 of the data processing device 290 is the hardware of the processing unit 191, the input unit 192, and the display unit 193 of the data processing device 190 of the THC measurement device 100, respectively. Description is omitted because it is substantially the same as the configuration of.

The processing unit 291 stores a reference spectrum A ₀ (λ) illustrated in FIG. 11 in advance.
As shown in FIG. 11, the reference spectrum A ₀ (λ) includes a short-wavelength side reference spectrum A _S0 (λ) composed of a wavelength band equal to or less than the non-absorption wavelength λa and a long-wavelength side reference composed of a wavelength band equal to or greater than the non-absorption wavelength λa. The spectrum is divided into two parts, A _L0 (λ).
The “non-absorption wavelength” is a wavelength set within the range of the “non-absorption wavelength band (see (d) in FIG. 3 and FIG. 11)”. In the present embodiment, it is desirable to set the non-absorption wavelength λa within a range of 2.950 μm to 3.550 μm, and it is more preferable to set the non-absorption wavelength λa within a range of 3.100 μm to 3.200 μm. desirable.
The processing unit 291 stores a short wavelength side reference spectrum A _S0 (λ) and a long wavelength side reference spectrum A _L0 (λ) in advance.

The processing unit 291 previously calculates and stores the short wavelength side first corrected reference spectrum A _S1 (λ) and the long wavelength side first corrected reference spectrum A _L1 (λ) shown in FIG.

The “short wavelength side first corrected reference spectrum” is calculated by subtracting the light intensity at the shortest wavelength point in the short wavelength side reference spectrum from the short wavelength side reference spectrum, and is expressed as a function of wavelength.
In this embodiment, pulling the light intensity A _S0 of the shortest wavelength point A ₀₁ in the short-wavelength-side reference spectrum A _S0 short wavelength side reference from (lambda) spectrum A _S0 (λ) (black squares in FIG. 11) ([lambda] min) Thus, the short wavelength side first corrected reference spectrum A _S1 (λ) shown in FIG. 12 is calculated (A _S1 (λ) = A _S0 (λ) −A _S0 (λmin)).

As shown in FIG. 12, the value of the coordinate A _S1 (λmin) on the vertical axis of the shortest wavelength point A ₁₁ (black square in FIG. 12) in the short wavelength side first corrected reference spectrum A _S1 (λ) is zero ( A _S1 (λmin) = 0), the shortest wavelength point A ₁₁ is located on the horizontal axis.

The “long wavelength side first corrected reference spectrum” is calculated by subtracting the light intensity at the longest wavelength point in the long wavelength side reference spectrum from the long wavelength side reference spectrum, and is expressed as a function of wavelength.
In this embodiment, pulling the light intensity A _L0 of the long-wavelength-side reference spectrum A _L0 (lambda) from the long-wavelength-side reference spectrum A _L0 (lambda) maximum wavelength point A ₀₂ in (white squares in FIG. 11) (.lambda.max) Thus, the long wavelength side first corrected reference spectrum A _L1 (λ) shown in FIG. 12 is calculated (A _L1 (λ) = A _L0 (λ) −A _L0 (λmax)).
As shown in FIG. 12, the value of the coordinate A _L1 (λmax) on the vertical axis of the longest wavelength point A ₁₂ (white square in FIG. 12) in the long wavelength side first corrected reference spectrum A _L1 (λ) is zero ( A _L1 (λmax) = 0), the longest wavelength point A ₁₂ is located on the horizontal axis.

The processing unit 291 previously calculates and stores the second corrected reference spectrum A ₂ (λ) shown in FIG.
The “second corrected reference spectrum” is calculated by subtracting the light intensity of the shortest wavelength point and the light intensity of the longest wavelength point in the reference spectrum from the reference spectrum and adding a constant, and as a function of wavelength. expressed.
In the present embodiment, by subtracting the light intensity A _L0 (λmax) at the longest wavelength point A _{02 in} the reference spectrum A ₀ (λ) from the reference spectrum A ₀ (λ) and adding a constant C, the second shown in FIG. A corrected reference spectrum A ₂ (λ) is calculated (A ₂ (λ) = A ₀ (λ) −A _L0 (λmax) + C).
As shown in FIG. 13, the value of the coordinate A _L2 (λmax) on the vertical axis of the longest wavelength point A ₂₂ (white square in FIG. 13) in the second corrected reference spectrum A ₂ (λ) is C (A _L2 ( λmax) = C).
The constant C is added for the sake of convenience in order to avoid the case where the logarithmic operation included in the calculation based on Equation 1 becomes impossible. Therefore, the value of the constant C is usually a positive value. However, if the logarithmic operation is not disabled without adding the constant C, the value of the constant C can be set to zero.

Based on the corrected measurement signal and the spectral period signal acquired from the lock-in amplifier 80, the processing unit 291 calculates “absorption spectrum B ₀ (λ) of the measurement target gas 1” illustrated in FIG.
More specifically, the processing unit 291 collates the corrected measurement signal and the spectral periodic signal, and sequentially performs an operation of specifying which wavelength band the acquired corrected measurement signal indicates the light intensity, thereby performing measurement. An absorption spectrum B ₀ (λ) of the target gas 1 is calculated.
The shortest wavelength and the longest wavelength of the absorption spectrum B ₀ (λ) shown in FIG. 14 respectively match the shortest wavelength and the longest wavelength of the reference spectrum A ₀ (λ) shown in FIG.

As shown in FIG. 14, the processing unit 291 has an absorption spectrum B ₀ (λ) consisting of a short wavelength side absorption spectrum B _S0 (λ) consisting of a wavelength band equal to or less than the non-absorption wavelength λa and a wavelength band equal to or greater than the non-absorption wavelength λa. Dividing into long wavelength side absorption spectrum B _L0 (λ).

Based on the short wavelength side absorption spectrum B _S0 (λ) of the measurement target gas 1, the processing unit 291 calculates the short wavelength side first corrected absorption spectrum B _S1 (λ) of the measurement target gas 1 shown in FIG.
"Short wavelength side first corrected absorption spectrum of the measurement target gas" is calculated by subtracting the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum from the short wavelength side absorption spectrum of the measurement target gas, and as a function of wavelength. expressed.
In the present embodiment, subtracting the light intensity B _S0 of the shortest wavelength point B ₀₁ at the short wavelength side absorption spectrum B _S0 (lambda) from the short wavelength side absorption spectrum B _S0 (λ) (black circles in FIG. 14) ([lambda] min) Accordingly, the short wavelength side first corrected absorption spectrum B _S1 (λ) shown in FIG. 15 is calculated (B _S1 (λ) = B _S0 (λ) −B _S0 (λmin)).

As shown in FIG. 15, the value of the coordinate B _S1 (λmin) on the vertical axis of the shortest wavelength point B ₁₁ (black circle in FIG. 15) in the first corrected absorption spectrum B _S1 (λ) on the short wavelength side is zero (B _S1 (λmin) = 0), the shortest wavelength point B ₁₁ is located on the horizontal axis.
Also, short wavelength side first correction absorption spectrum B _S1 shortest wavelength point B ₁₁ in (lambda) (black circles in FIG. 15) and the first short wavelength side correction reference spectra A _S1 (lambda) the shortest wavelength points in A ₁₁ (FIG. 12 and the black square in FIG. 15 overlap (the coordinates of the vertical axis coincide).

Based on the long wavelength side absorption spectrum B _L0 (λ) of the measurement target gas 1, the processing unit 291 calculates the long wavelength side first corrected absorption spectrum B _L1 (λ) of the measurement target gas 1 shown in FIG.
The "long wavelength side first corrected absorption spectrum of the measurement target gas" is calculated by subtracting the light intensity at the longest wavelength point in the long wavelength side absorption spectrum from the long wavelength side absorption spectrum of the measurement target gas, and as a function of wavelength. expressed.
In the present embodiment, subtracting the light intensity B _L0 of the longest wavelength point B ₀₂ at the long wavelength side absorption spectrum B _L0 (lambda) from the long wavelength side absorption spectrum B _L0 (λ) (white circles in FIG. 14) (.lambda.max) Thus, the long wavelength side first corrected absorption spectrum B _L1 (λ) shown in FIG. 15 is calculated (B _L1 (λ) = B _L0 (λ) −B _L0 (λmax)).

As shown in FIG. 15, the value of the coordinate B _L1 (λmax) on the vertical axis of the longest wavelength point B ₁₂ (white circle in FIG. 15) in the first corrected absorption spectrum B _L1 (λ) on the long wavelength side is zero (B _L1 (λmax) = 0), the longest wavelength point B ₁₂ is located on the horizontal axis.
Furthermore, the longest wavelength point A ₁₂ (Fig at the longest wavelength point B ₁₂ (white circles in Fig. 15) and the first correction reference spectrum A _L1 long wavelength side (lambda) of the first correction absorption spectrum B _L1 long wavelength side (lambda) 12 and the white square in FIG. 15 overlap (the coordinates of the vertical axis coincide).

Based on the short wavelength side first corrected reference spectrum A _S1 (λ) and the short wavelength side first corrected absorption spectrum B _S1 (λ), the processing unit 291 performs the short wavelength side second corrected absorption spectrum B _S2 shown in FIG. (Λ) is calculated.
“Short-wavelength side second corrected absorption spectrum” is “the value obtained by dividing the light intensity at the longest wavelength point in the short-wavelength side first corrected reference spectrum by the light intensity at the longest wavelength point in the short-wavelength side first corrected absorption spectrum”. It is calculated by multiplying the first corrected absorption spectrum on the short wavelength side and expressed as a function of wavelength.
In this embodiment, the light intensity A _S1 (λa) of the longest wavelength point A _{13 in} the short wavelength side first corrected reference spectrum A _S1 (λ) is used as the longest wavelength point in the short wavelength side first corrected absorption spectrum B _S1 (λ). By multiplying the value obtained by dividing the light intensity B _S1 (λa) of B ₁₃ by the short wavelength side first corrected absorption spectrum B _S1 (λ), the short wavelength side second corrected absorption spectrum B _S2 (λ) shown in FIG. Is calculated (B _S2 (λ) = {A _S1 (λa) / B _S1 (λa)} × B _S1 (λ)).

As shown in FIG. 16, the value of the coordinate B _S2 (λmin) on the vertical axis of the shortest wavelength point B ₂₁ (black circle in FIG. 16) in the second corrected absorption spectrum B _S2 (λ) on the short wavelength side is zero (B _S2 (λmin) = 0), the shortest wavelength point B ₂₁ is located on the horizontal axis.
In addition, the shortest wavelength point B ₂₁ (black circle in FIG. 16) in the short wavelength side second corrected absorption spectrum B _S2 (λ) and the shortest wavelength point A ₁₁ in the short wavelength side first corrected reference spectrum A _S1 (λ) (FIG. 12 and the black squares in FIG. 16 overlap (the coordinates of the vertical axis coincide).
Furthermore, in the shortest wavelength side second corrected absorption spectrum B _S2 (λ), the longest wavelength point B ₂₃ (the white circle drawn in the horizontal line in FIG. 16) and the short wavelength side first corrected reference spectrum A _S1 (λ). The longest wavelength point A ₁₃ (the white square in which the horizontal line in FIGS. 12 and 16 is drawn) overlaps (the coordinates of the vertical axis coincide).

Based on the long wavelength side first corrected reference spectrum A _L1 (λ) and the long wavelength side first corrected absorption spectrum B _L1 (λ), the processing unit 291 performs the long wavelength side second corrected absorption spectrum B _L2 shown in FIG. (Λ) is calculated.
“Long wavelength side second corrected absorption spectrum” is “the value obtained by dividing the light intensity at the shortest wavelength point in the long wavelength side first corrected reference spectrum by the light intensity at the shortest wavelength point in the long wavelength side first corrected absorption spectrum”. Calculated by multiplying the first corrected absorption spectrum on the long wavelength side and expressed as a function of wavelength.
In the present embodiment, the light intensity A _L1 (λa) of the shortest wavelength point A _{14 in} the long wavelength side first corrected reference spectrum A _L1 (λ) is used as the shortest wavelength point in the long wavelength side first corrected absorption spectrum B _L1 (λ). The long wavelength side second corrected absorption spectrum B _L2 (λ) shown in FIG. 16 is obtained by multiplying the value obtained by dividing the B ₁₄ light intensity B _L1 (λa) by the long wavelength side first corrected absorption spectrum B _L1 (λ). Is calculated (B _L2 (λ) = {A _L1 (λa) / B _L1 (λa)} × B _L1 (λ)).

As shown in FIG. 16, the value of the coordinate B _L2 (λmax) on the vertical axis of the longest wavelength point B ₂₂ (white circle in FIG. 16) in the second corrected absorption spectrum B _L2 (λ) on the long wavelength side is zero (B _L2 (λmax) = 0), the longest wavelength point B ₂₂ is located on the horizontal axis.
Further, the longest wavelength point B ₂₂ (white circle in FIG. 16) in the long wavelength side second corrected absorption spectrum B _L2 (λ) and the longest wavelength point A ₁₂ in the long wavelength side first corrected reference spectrum A _L1 (λ) (FIG. 12 and the white squares in FIG. 16 overlap (the coordinates of the vertical axis coincide).
Further, the shortest wavelength point B ₂₄ in the long wavelength side second corrected absorption spectrum B _L2 (λ) (the white circle in which the vertical line in FIG. 16 is drawn) and the long wavelength side first corrected reference spectrum A _L1 (λ). The shortest wavelength point A _{14 in} FIG. 12 (the white square with the vertical line in FIG. 12 and FIG. 16 drawn inside) overlaps (the coordinates of the vertical axis coincide).

Based on the short wavelength side second corrected absorption spectrum B _S2 (λ) and the long wavelength side second corrected absorption spectrum B _L2 (λ), the processing unit 291 performs the third corrected absorption spectrum B ₃ (λ) shown in FIG. Is calculated (generated).

  The procedure for calculating (generating) the third corrected absorption spectrum varies depending on the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum and the light intensity at the longest wavelength point in the long wavelength side absorption spectrum.

(I) When the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is smaller than the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the following (i-1), (i-2) and ( The third corrected absorption spectrum is calculated (generated) according to the procedure of i-3).
(I-1) A short wavelength side third corrected absorption spectrum is calculated by adding a “constant” to the short wavelength side second corrected absorption spectrum.
(I-2) The absolute value of the difference between the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum and the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, and The long wavelength side third corrected absorption spectrum is calculated by adding "constant".
(I-3) A third corrected absorption spectrum is generated by connecting the longest wavelength point of the short wavelength side third corrected absorption spectrum to the shortest wavelength point of the long wavelength side third corrected absorption spectrum.

(Ii) When the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is larger than the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the following (ii-1), (ii-2) and ( A third corrected absorption spectrum is calculated (generated) according to the procedure of ii-3).
(Ii-1) The short wavelength side second corrected absorption spectrum includes “the absolute value of the difference between the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum and the light intensity at the longest wavelength point in the long wavelength side absorption spectrum” and “ By adding “constant”, the third corrected absorption spectrum on the short wavelength side is calculated.
(Ii-2) A long wavelength side third corrected absorption spectrum is calculated by adding a “constant” to the long wavelength side second corrected absorption spectrum.
(Ii-3) A third corrected absorption spectrum is generated by connecting the longest wavelength point of the short wavelength side third corrected absorption spectrum to the shortest wavelength point of the long wavelength side third corrected absorption spectrum.

(Iii) When the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is the same as the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the following (iii-1), (iii-2) and A third corrected absorption spectrum is calculated (generated) according to the procedure of (iii-3).
(Iii-1) The short wavelength side third corrected absorption spectrum is calculated by adding “constant” to the short wavelength side second corrected absorption spectrum.
(Iii-2) A long wavelength side third corrected absorption spectrum is calculated by adding a “constant” to the long wavelength side second corrected absorption spectrum.
(Iii-3) The third corrected absorption spectrum is generated by connecting the longest wavelength point of the short wavelength side third corrected absorption spectrum to the shortest wavelength point of the long wavelength side third corrected absorption spectrum.

As shown in FIG. 14, in this embodiment, the light intensity B _S0 (λmin) at the shortest wavelength point B ₀₁ of the short wavelength side absorption spectrum B _S0 (λ) is the longest wavelength point B of the long wavelength side absorption spectrum B _L0 (λ). _Since the light intensity B _L0 (λmax) of ₀₂ is larger (B _S0 (λmin)> B _L0 (λmax)), this corresponds to the above (ii).

Accordingly, the processing unit 291 adds “the light intensity B _S0 (λmin) at the shortest wavelength point B ₀₁ of the short wavelength side absorption spectrum B _S0 (λ) to the short wavelength side second corrected absorption spectrum B _S2 (λ) and the long wavelength side. By adding the “absolute value of the difference from the light intensity B _L0 (λmax) of the longest wavelength point B ₀₂ of the absorption spectrum B _L0 (λ)” and the “constant C”, the third corrected absorption spectrum on the short wavelength side shown in FIG. B _S3 (λ) is calculated (B _S3 (λ) = B _S2 (λ) + {B _S0 (λmin) −B _L0 (λmax)} + C).
Further, the processing unit 291 calculates a long wavelength side third corrected absorption spectrum B _L3 (λ) shown in FIG. 17 by adding “constant C” to the long wavelength side second corrected absorption spectrum B _L2 (λ). (B _L3 (λ) = B _L2 (λ) + C).
Further, as shown in FIG. 17, the processing unit 291 connects the longest wavelength point of the short wavelength side third corrected absorption spectrum B _S3 (λ) to the shortest wavelength point of the long wavelength side third corrected absorption spectrum B _L3 (λ). By combining them, a third corrected absorption spectrum B ₃ (λ) is generated. Here, the longest wavelength point of the short wavelength side third corrected absorption spectrum B _S3 (λ) and the shortest wavelength point of the long wavelength side third corrected absorption spectrum B _L3 (λ) are the short wavelength side third corrected absorption spectrum B. The coordinates of the horizontal axis and the vertical axis are the same from the time before connecting _S3 (λ) to the long wavelength side third corrected absorption spectrum B _L3 (λ).

  The constant values added to the short wavelength side second corrected absorption spectrum and the long wavelength side second corrected absorption spectrum are the same as the constant values added to the first corrected reference spectrum when calculating the second corrected reference spectrum. It is.

The constant C is added for the sake of convenience in order to avoid the case where the logarithmic operation included in the calculation based on Equation 1 becomes impossible. Therefore, the value of the constant C is usually a positive value.
However, if the logarithmic operation is not disabled without adding the constant C, the value of the constant C can be set to zero.

As shown in FIG. 17, the longest wavelength point B ₃₂ (white circle in FIG. 17) in the third corrected absorption spectrum B ₃ (λ) and the longest wavelength point A ₂₂ in the second corrected reference spectrum A ₂ (λ) (FIG. 13 and FIG. The white squares in FIG. 17 overlap (the coordinates on the vertical axis coincide).
Further, the shortest wavelength point B ₃₁ (black circle in FIG. 17) in the third corrected absorption spectrum B ₃ (λ) and the shortest wavelength point A ₂₁ in the second corrected reference spectrum A ₂ (λ) (in FIGS. 13 and 17). The black squares overlap (the coordinates of the vertical axis match).
Further, the short-wavelength side third corrected absorption spectrum B _S3 (λ) and the long-wavelength side third corrected absorption spectrum B _L3 (λ) are joined, that is, non-absorption in the third corrected absorption spectrum B ₃ (λ). The wavelength point B _3a (the white circle with a cross in FIG. 17) and the non-absorption wavelength point A _2a in the second corrected reference spectrum A ₂ (λ) (the cross in FIG. 13 and FIG. 17). The white squares attached are overlapped (the coordinates of the vertical axis coincide).

Thus, a series of processing (calculations) performed by the processing unit 291 on the reference spectrum A ₀ (λ) and the absorption spectrum B ₀ (λ) is substantially the shortest wavelength point of the reference spectrum A ₀ (λ). a ₀₁ the shortest wavelength point B ₀₁ and the overlap of the absorption spectrum B ₀ (λ), the reference spectrum a ₀ (λ) longest wavelength points a ₀₂ and the longest wavelength point B ₀₂ of the absorption spectrum B ₀ (lambda) overlaps the In addition, this corresponds to _performing correction so that the non-absorption wavelength point A _0a in the reference spectrum A ₀ (λ) and the non-absorption wavelength point B _0a in the absorption spectrum B ₀ (λ) overlap.
In addition, a series of processing (calculation) performed by the processing unit 291 on the reference spectrum A ₀ (λ) and the absorption spectrum B ₀ (λ) is substantially the point of the non-absorption wavelength in the reference spectrum and the absorption spectrum. The absorption spectrum is translated in the vertical axis direction so that the non-absorption wavelength point overlaps, and then the absorption spectrum is maintained while the non-absorption wavelength point in the reference spectrum and the non-absorption wavelength point in the absorption spectrum are kept overlapping. In the absorption spectrum, the portion below the non-absorption wavelength is expanded or reduced in the vertical axis direction so that the shortest wavelength point of the reference spectrum overlaps with the shortest wavelength point of the absorption spectrum, and the portion of the absorption spectrum above the non-absorption wavelength is in the vertical axis direction. The longest wavelength point of the reference spectrum by zooming in or out Is equivalent to performing correction to overlap the longest wavelength point of the absorption spectrum.

As shown in FIG. 17, when comparing the second corrected reference spectrum A ₂ (λ) and the third corrected absorption spectrum B ₃ (λ), “(a) Wavelength band absorbed by hydrocarbons belonging to the group consisting of alkane and alkene” , (B) a wavelength band absorbed by a hydrocarbon belonging to the group consisting of aromatic hydrocarbons, and (c) a wavelength band excluding a wavelength band absorbed by the hydrocarbon belonging to the group consisting of alkynes, that is, “(c) The light intensities in the wavelength band shorter than the wavelength band of (1), the wavelength band longer than the wavelength band of (a) and the wavelength band of (d) ”are in good agreement, and the disturbance factor is eliminated.

Based on the second corrected reference spectrum A ₂ (λ), the third corrected absorption spectrum B ₃ (λ) and Equation 1, the processing unit 291 (a) alkane and alkene among the hydrocarbons contained in the measurement target gas 1 (B) a group consisting of aromatic hydrocarbons and (c) a group consisting of alkynes are calculated.

The processing unit 291 calculates “the sum of the concentrations of hydrocarbons belonging to the group consisting of alkane and alkene” based on “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkane and alkene” calculated based on Equation 1. Based on the “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”, the “sum of the concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons” is calculated, and “from alkyne Based on the “absorbance in the absorption wavelength band of hydrocarbons belonging to a certain group”, “the sum of the concentrations of hydrocarbons belonging to the group consisting of alkynes” is calculated.
Specifically, the processing unit 291 includes the measurement target gas 1 as the product of the coefficient K1 stored in the processing unit 291 in advance and “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkane and alkene”. The “sum of the concentrations of hydrocarbons belonging to the group consisting of alkanes and alkenes” is calculated.
Similarly, the processing unit 291 is included in the measurement target gas 1 as the product of the coefficient K2 stored in advance in the processing unit 291 and “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”. The “sum of the concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons” is calculated.
Similarly, the processing unit 291 obtains “from alkyne” contained in the measurement target gas 1 as the product of the coefficient K3 stored in advance in the processing unit 291 and “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkyne”. The sum of the concentrations of hydrocarbons belonging to a certain group is calculated.

  The processing unit 291 calculates the above-mentioned “sum of concentrations of hydrocarbons belonging to the group consisting of alkanes and alkenes”, “sum of concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”, and “groups consisting of alkynes” As the sum of the “sum of the concentrations of hydrocarbons belonging to”, “the total hydrocarbon concentration of the gas 1 to be measured” is calculated.

  The processing unit 291 includes the calculated “sum of the concentrations of hydrocarbons belonging to the group consisting of alkanes and alkenes”, “sum of the concentrations of hydrocarbons belonging to the groups consisting of aromatic hydrocarbons”, and “groups consisting of the alkynes” “Sum of hydrocarbon concentrations” and “total hydrocarbon concentration of measurement target gas 1” are stored as appropriate.

As described above, the THC measuring apparatus 200 is
An infrared lamp 10 for generating light;
A spectroscope 20 for periodically changing the wavelength of light generated by the infrared lamp 10, and
A photodiode 30 for detecting the intensity of light whose wavelength has been varied by the spectroscope 20;
A gas container 40 which is disposed at a position sandwiched between the spectroscope 20 and the photodiode 30 in an optical path Z formed by the infrared lamp 10, the spectroscope 20 and the photodiode 30, can accommodate the measurement target gas 1 and can transmit light. When,
References including wavelength bands absorbed by (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes among the hydrocarbons contained in measurement target gas 1 In the spectrum A ₀ (λ), a short wavelength side reference spectrum A _S0 (λ) composed of a wavelength band of the non-absorption wavelength λa or less and a long wavelength side reference spectrum A _L0 (λ) composed of a wavelength band of the non-absorption wavelength λa or more. The second wavelength is calculated by subtracting the light intensity A _S0 (λmin) at the shortest wavelength point A ₀₁ in the short wavelength side reference spectrum A _S0 (λ) from the short wavelength side reference spectrum A _S0 (λ). one correction reference spectra A _S1 (λ) and the long-wavelength-side reference space from the long-wavelength-side reference spectrum A _L0 (lambda) Torr A _L0 (λ) stored in advance longest wavelength point A ₀₂ of the light intensity A _L0 first correcting long-wavelength side is calculated by subtracting the (.lambda.max) reference spectra A _L1 (lambda) in the reference spectrum A ₀ ( The second corrected reference spectrum A ₂ (λ) calculated by subtracting the light intensity A _L0 (λmax) at the longest wavelength point A ₀₂ in the reference spectrum A ₀ (λ) from the λ) and adding a constant C is stored in advance. The absorption spectrum B ₀ (λ) of the measurement target gas 1 is calculated based on the intensity of light detected by the photodiode 30, and the absorption spectrum B ₀ (λ) is a short wavelength having a wavelength band equal to or less than the non-absorption wavelength λa. A side absorption spectrum B _S0 (λ) and a long wavelength side absorption spectrum B _L0 (λ) composed of a wavelength band longer than the non-absorption wavelength λa are divided into two, and the short wavelength side absorption spectrum B _{S0 is} divided. By subtracting the light intensity B _S0 (λmin) at the shortest wavelength point B ₀₁ of the short wavelength side absorption spectrum B _S0 (λ) from (λ), the short wavelength side first corrected absorption spectrum B _S1 (λ) is calculated. By subtracting the light intensity B _L0 (λmax) of the longest wavelength point B ₀₂ of the long wavelength side absorption spectrum B _L0 (λ) from the wavelength side absorption spectrum B _L0 (λ), the long wavelength side first corrected absorption spectrum B _L1 (λ ) To calculate the light intensity A _S1 (λa) of the longest wavelength point A ₁₃ in the short wavelength side first corrected reference spectrum A _S1 (λ) and the longest wavelength point in the short wavelength side first corrected absorption spectrum B _S1 (λ). The short wavelength side second corrected absorption spectrum B _S2 (λ) is calculated by multiplying the value obtained by dividing the light intensity B _S1 (λa) of B ₁₃ by the short wavelength side first corrected absorption spectrum B _S1 (λ), wavelength side first correction reference spectrum a _L1 to (lambda) Kicking light intensity A _L1 ([lambda] a) the longer wavelength side divided by the light intensity B _L1 of the shortest wavelength point B ₁₄ ([lambda] a) a in the long wavelength side first correcting absorption spectrum B _L1 (lambda) of the shortest wavelength points A ₁₄ The long wavelength side second corrected absorption spectrum B _L2 (λ) is calculated by multiplying the first corrected absorption spectrum B _L1 (λ), and the short wavelength side absorption spectrum B _S2 (λ) is calculated. B _S0 absolute value of the difference between the light intensity B _L0 of the longest wavelength point B ₀₂ (.lambda.max) of the light intensity of the shortest wavelength point B ₀₁ of (λ) B _S0 (λmin) the long wavelength side absorption spectrum B _L0 (lambda) By adding the constant C and the short wavelength side third corrected absorption spectrum B _S3 (λ), the long wavelength side third corrected absorption spectrum B _L2 (λ) is added. calculating the absorption spectrum B _L3 (λ), the short-wavelength side third auxiliary The longest wavelength point of the absorption spectrum B _S3 (λ) to generate a third correction absorption spectrum B ₃ (lambda) by joining the long wavelength side third correction absorption spectrum B _L3 (λ), the second correction reference spectra A ₂ (λ), third corrected absorption spectrum B ₃ (λ), and hydrocarbons contained in the gas 1 to be measured based on Equation 1 (a) a group consisting of alkane and alkene, (b) from aromatic hydrocarbon And (c) a group of alkynes, the amount of light absorption in the wavelength band absorbed by each of the groups (in this embodiment, X ₁ , X ₂ and X ₃ ) is calculated and corresponds to each calculated group. A data processing device 290 (more precisely, a processing unit 291) that calculates the concentration of hydrocarbons belonging to each group based on the amount of light absorption;
It comprises.
With this configuration, the THC measurement device 200 can cause disturbance factors (for example, the optical system (lens or the like) of the THC measurement device 200) or the inlet-side window member 42 and the outlet provided in the gas container 40. Gawamado member 43 is dirty, or the like gas container 40 is infrared light is radiated from the material constituting the temperature rising gas container 40 (metal or the like) by heat conduction from the measurement target gas 1) absorption spectrum B ₀ It is possible to eliminate the influence on (λ), and consequently the concentration of hydrocarbons contained in the measurement target gas 1 can be measured with high accuracy.

Below, 2nd embodiment of the hydrocarbon concentration measuring method which concerns on this invention is described using FIG.
The second embodiment of the hydrocarbon concentration measuring method according to the present invention is a method of measuring the concentration sum of hydrocarbons contained in the measurement target gas 1 using the THC measuring device 200.
As shown in FIG. 18, the second embodiment of the hydrocarbon concentration measuring method according to the present invention includes a detection step S2100, an absorption spectrum calculation step S2200, a first corrected absorption spectrum calculation step S2300, a second corrected absorption spectrum calculation step S2400, a first step. Three corrected absorption spectrum calculation steps S2500, a light absorption amount calculation step S2600, and a concentration calculation step S2700 are provided.

The detection step S2100 is a step in which the photodiode 30 detects the intensity of light generated by the infrared lamp 10 and transmitted through the measurement target gas 1 accommodated in the gas container 40.
In the present embodiment, the detection step S2100 is repeatedly performed at a predetermined cycle (spectral cycle of the spectrometer 20).

In the absorption spectrum calculation step S2200, the data processing device 290 (more precisely, the processing unit 291) calculates the absorption spectrum B ₀ (λ) of the measurement target gas 1 based on the intensity of light detected by the photodiode 30. It is a process to do.
When the absorption spectrum calculation step S2200 ends, the process proceeds to the first corrected absorption spectrum calculation step S2300.

In the first corrected absorption spectrum calculation step S2300, the data processor 290 (more precisely, the processing unit 291) causes the absorption spectrum B ₀ (λ) to be converted into a short wavelength side absorption spectrum B having a wavelength band equal to or less than the non-absorption wavelength λa. _S0 (lambda) and the non-absorption wavelength consisting λa or more wavelength band bisected to the long wavelength side absorption spectrum B _L0 (λ), the short-wavelength side absorption spectrum B _S0 (λ) shorter wavelength side absorption spectrum from B _S0 (lambda ) Is used to calculate the short wavelength-side first corrected absorption spectrum B _S1 (λ) by subtracting the light intensity B ₀ (λmin) of the shortest wavelength point B _{01, and from} the long wavelength side absorption spectrum B _L0 (λ) to the long wavelength side This is a step of calculating the long-wavelength-side first corrected absorption spectrum B _L1 (λ) by subtracting the light intensity B ₀ (λmax) at the longest wavelength point B ₀₂ in the absorption spectrum B _L0 (λ).
If 1st correction | amendment absorption spectrum calculation process S2300 is complete | finished, it will transfer to 2nd correction | amendment absorption spectrum calculation process S2400.

In the second corrected absorption spectrum calculation step S2400, the data processing device 290 (more precisely, the processing unit 291) determines the light intensity A _S1 of the longest wavelength point A _{13 in} the short wavelength side first corrected reference spectrum A _S1 (λ). the ([lambda] a) the light intensity B _S1 first correcting absorption spectrum divided by ([lambda] a) the short wavelength side B _S1 of the longest wavelength point B ₁₃ (lambda) of the first correcting absorption spectrum B _S1 short-wavelength side (lambda) By multiplying, the short wavelength side second corrected absorption spectrum B _S2 (λ) is calculated, and the light intensity A _L1 (λa) at the shortest wavelength point A _{14 in} the long wavelength side first corrected reference spectrum A _L1 (λ) is set to the long wavelength. side first correcting absorption spectrum B _L1 (lambda) long wavelength side by multiplying the light intensity B _L1 first correcting absorption spectrum divided by ([lambda] a) the longer wavelength side B _L1 of the shortest wavelength point B ₁₄ (lambda) in Second corrected absorption spectrum A step of calculating B _L2 a (lambda).
If 2nd correction | amendment absorption spectrum calculation process S2400 is complete | finished, it will transfer to 3rd correction | amendment absorption spectrum calculation process S2500.

In the third corrected absorption spectrum calculation step S2500, the data processing device 290 (more precisely, the processing unit 291) uses the short wavelength side absorption spectrum B _S0 (λ) to the short wavelength side second corrected absorption spectrum B _S2 (λ). The absolute value of the difference between the light intensity B _S0 (λmin) at the shortest wavelength point B ₀₁ and the light intensity B _L0 (λmax) at the longest wavelength point B ₀₂ of the long wavelength side absorption spectrum B _L0 (λ) is added. By calculating the short wavelength side third corrected absorption spectrum B _S3 (λ) and adding a constant C to the long wavelength side second corrected absorption spectrum B _L2 (λ), the long wavelength side third corrected absorption spectrum B _L3 ( λ) is calculated to connect the longest wavelength point of the short wavelength side third corrected absorption spectrum B _S3 (λ) to the shortest wavelength point of the long wavelength side third corrected absorption spectrum B _L3 (λ), thereby correcting the third corrected absorption. spectrum B ₃ (λ It is a process that generates a.
When the third corrected absorption spectrum calculating step S2500 is completed, the process proceeds to the light absorption amount calculating step S2600.

In the light absorption amount calculating step S2600, the data processing device 290 (more precisely, the processing unit 291) is based on the second corrected reference spectrum A ₂ (λ), the third corrected absorption spectrum B ₃ (λ), and Equation 1. Among the hydrocarbons contained in the gas 1 to be measured, light in the wavelength band absorbed by each of (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. Is the step of calculating the amount of absorption (in this embodiment, X ₁ , X ₂ and X ₃ ).
When the light absorption amount calculating step S2600 is completed, the process proceeds to the concentration calculating step S2700.

In the concentration calculation step S2700, the data processing device 290 (more precisely, the processing unit 291) includes (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. This is a step of calculating the concentration of the hydrocarbons belonging to each group based on the amount of light absorbed by each of these (in this embodiment, X ₁ , X ₂ and X ₃ ).

As described above, the second embodiment of the hydrocarbon concentration measuring method according to the present invention is:
An infrared lamp 10 for generating light;
A spectroscope 20 for periodically changing the wavelength of light generated by the infrared lamp 10, and
A photodiode 30 for detecting the intensity of light whose wavelength has been varied by the spectroscope 20;
A gas container 40 which is disposed at a position sandwiched between the spectroscope 20 and the photodiode 30 in an optical path Z formed by the infrared lamp 10, the spectroscope 20 and the photodiode 30, can accommodate the measurement target gas 1 and can transmit light. When,
References including wavelength bands absorbed by (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes among the hydrocarbons contained in measurement target gas 1 In the spectrum A ₀ (λ), a short wavelength side reference spectrum A _S0 (λ) composed of a wavelength band of the non-absorption wavelength λa or less and a long wavelength side reference spectrum A _L0 (λ) composed of a wavelength band of the non-absorption wavelength λa or more. The second wavelength is calculated by subtracting the light intensity A _S0 (λmin) at the shortest wavelength point A ₀₁ in the short wavelength side reference spectrum A _S0 (λ) from the short wavelength side reference spectrum A _S0 (λ). one correction reference spectra A _S1 (λ) and the long-wavelength-side reference space from the long-wavelength-side reference spectrum A _L0 (lambda) Torr A _L0 (λ) stored in advance longest wavelength point A ₀₂ of the light intensity A _L0 first correcting long-wavelength side is calculated by subtracting the (.lambda.max) reference spectra A _L1 (lambda) in the reference spectrum A ₀ ( The second corrected reference spectrum A ₂ (λ) calculated by subtracting the light intensity A _L0 (λmax) of the longest wavelength point A ₀₂ in the reference spectrum A ₀ (λ) and adding the constant C from the reference spectrum A ₀ (λ) is stored in advance. And a data processing device 290 for calculating the concentration of hydrocarbons contained in the measurement target gas 1 based on the intensity of light detected by the photodiode 30;
A method for measuring the concentration of hydrocarbons contained in the gas 1 to be measured using a THC measuring device 200 comprising:
A detection step S2100;
Absorption spectrum calculation step S2200,
A first corrected absorption spectrum calculating step S2300;
A second corrected absorption spectrum calculating step S2400;
A third corrected absorption spectrum calculating step S2500;
A light absorption amount calculating step S2600;
Concentration calculation step S2700;
It comprises.
With this configuration, disturbance factors (for example, the optical system (lens or the like) of the THC measurement device 200) or the inlet side window member 42 and the outlet side window member 43 provided in the gas container 40 are contaminated. The effect that the temperature of the gas container 40 rises due to heat conduction from the measurement target gas 1 and infrared light is emitted from the material (metal, etc.) constituting the gas container 40) affects the absorption spectrum B ₀ (λ). Therefore, the concentration of hydrocarbons contained in the measurement target gas 1 can be measured with high accuracy.

  Hereinafter, a THC measuring apparatus 300 as a third embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIGS. 1 and 19 to 21.

A THC measurement apparatus 300 shown in FIG. 1 is an apparatus that measures the concentration sum of hydrocarbons contained in the measurement target gas 1.
The THC measurement apparatus 300 includes a frame 110, a light source side optical system unit 120, a gas container 40, a photodiode 30, a chopper / spectrometer control device 70, a lock-in amplifier 80, and a data processing device 390.

  Among the members constituting the THC measurement device 300, the frame 110, the light source side optical system unit 120, the gas container 40, the photodiode 30, the chopper / spectrometer control device 70, and the lock-in amplifier 80 constitute the THC measurement device 100. Since it is substantially the same as a member, description is abbreviate | omitted.

The data processing device 390 is an embodiment of the concentration calculation device according to the present invention.
Based on the intensity of light received by the photodiode 30, the data processing device 390 includes (a) a group consisting of alkanes and alkenes, and (b) an aromatic hydrocarbon among the hydrocarbons contained in the measurement target gas 1. A concentration sum of hydrocarbons belonging to the group and (c) the group consisting of alkynes is calculated for each group.
The data processing device 390 includes a processing unit 391, an input unit 392, and a display unit 393.
The hardware configuration of the processing unit 391, the input unit 392, and the display unit 393 of the data processing device 390 is the hardware of the processing unit 191, the input unit 192, and the display unit 193 of the data processing device 190 of the THC measurement device 100, respectively. Description is omitted because it is substantially the same as the configuration of.

The processing unit 391 stores a reference gas spectrum, that is, a reference spectrum A ₀ (λ) shown in FIG. 19 in advance.

As shown in FIG. 19, the reference spectrum A ₀ (λ) of this embodiment belongs to (a) a wavelength band absorbed by hydrocarbons belonging to a group consisting of alkanes and alkenes, and (b) belongs to a group consisting of aromatic hydrocarbons. All of the wavelength bands absorbed by hydrocarbons and (c) the wavelength bands absorbed by hydrocarbons belonging to the group consisting of alkynes are included.
Further, (d) non-absorption is provided at a position between (b) a wavelength band absorbed by a hydrocarbon belonging to the group consisting of aromatic hydrocarbons and (c) a wavelength band absorbed by a hydrocarbon belonging to the group consisting of alkynes. There is a wavelength band.
(D) The non-absorption wavelength band is a wavelength band not corresponding to any of the above (a) to (c), that is, a hydrocarbon belonging to the group consisting of alkanes and alkenes, a hydrocarbon belonging to the group consisting of aromatic hydrocarbons, In addition, the wavelength band does not absorb any of the hydrocarbons belonging to the alkyne group.
In this embodiment, it is desirable to set the non-absorption wavelength band within a range of 2.950 μm to 3.550 μm, and it is more preferable to set the non-absorption wavelength band within a range of 3.100 μm to 3.200 μm. desirable.

The processing unit 391 previously calculates and stores an average value D1 of the light intensity in the (d) non-absorption wavelength band of the reference spectrum A ₀ (λ).
In the present embodiment, the average value D1 is the integrated value S1 from the shortest wavelength λb to the longest wavelength λc of the (d) non-absorption wavelength band in the reference spectrum A ₀ (λ) (the area of the hatched portion in FIG. 19). Is divided by the difference between the longest wavelength λc and the shortest wavelength λb (D1 = {S1 / (λc−λb)}).
The “average value of the light intensity in the non-absorption wavelength band of the reference spectrum” according to the present invention is not limited to the average value D1 of the present embodiment, and may be a value calculated by another calculation method.
Another method for calculating the average value of the light intensity in the non-absorption wavelength band of the reference spectrum is to divide the sum of the light intensities of multiple points on the reference spectrum whose wavelengths are included in the non-absorption wavelength band by the number of points. The method etc. which make a value into an average value are mentioned.

The processing unit 391 calculates “absorption spectrum B ₀ (λ) of the measurement target gas 1” illustrated in FIG. 20 based on the corrected measurement signal and the spectral period signal acquired from the lock-in amplifier 80.

More specifically, the processing unit 391 compares the corrected measurement signal and the spectral periodic signal, and sequentially performs an operation of specifying which wavelength band the acquired corrected measurement signal indicates the light intensity. An absorption spectrum B ₀ (λ) of the target gas 1 is calculated.
The shortest wavelength and the longest wavelength of the absorption spectrum B ₀ (λ) shown in FIG. 20 respectively match the shortest wavelength and the longest wavelength of the reference spectrum A ₀ (λ) shown in FIG.

The processing unit 391 calculates the “corrected absorption spectrum B ₁ (λ) of the measurement target gas 1” illustrated in FIG. 21 based on the absorption spectrum B ₀ (λ) of the measurement target gas 1.
The processing unit 391 calculates the average value D2 of the light intensity in the (d) non-absorption wavelength band of the absorption spectrum B ₀ (λ) of the measurement target gas 1.
In the present embodiment, the average value D2 is the integrated value S2 from the shortest wavelength λb to the longest wavelength λc of (d) non-absorption wavelength band in the absorption spectrum B ₀ (λ) (the area of the hatched portion in FIG. 20). Is divided by the difference between the longest wavelength λc and the shortest wavelength λb (D2 = {S2 / (λc
-Λb)}).
The “average value of the light intensity in the non-absorption wavelength band of the absorption spectrum” according to the present invention is not limited to the average value D2 of the present embodiment, and may be a value calculated by another calculation method.
As another method of calculating the average value of the light intensity in the non-absorption wavelength band of the absorption spectrum, the sum of the light intensities at a plurality of points on the absorption spectrum whose wavelengths are included in the non-absorption wavelength band is divided by the number of the points. The method etc. which make a value into an average value are mentioned.
The processing unit 391 calculates the corrected absorption spectrum B ₁ (λ) by multiplying the absorption spectrum B ₀ (λ) by dividing the average value D1 by the average value D2 (B ₁ (λ) = (D1 / D2) × B ₀ (λ)).

Thus, a series of processing by the processing unit 291 makes to the absorption spectrum B ₀ (lambda) (operation), the reference spectrum A ₀ (lambda) and the absorption spectrum B ₀ "in (lambda) (a) alkanes and alkenes A wavelength band absorbed by hydrocarbons belonging to the group consisting of (b) a wavelength band absorbed by hydrocarbons belonging to the group consisting of aromatic hydrocarbons, and (c) a wavelength band absorbed by hydrocarbons belonging to the group consisting of alkynes The light intensities in the “wavelength band excluding“, ”that is, the“ wavelength band shorter than the wavelength band of (c), the wavelength band longer than the wavelength band of (a), and the wavelength band of (d) ”are matched well. Is. Therefore, the disturbance factor is excluded from the corrected absorption spectrum B ₁ (λ).

Based on the reference spectrum A ₀ (λ), the corrected absorption spectrum B ₁ (λ), and the following Equation 2, the processing unit 391 includes (a) a group of alkanes and alkenes among the hydrocarbons contained in the measurement target gas 1. , (B) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes, the amount of light absorbed in the wavelength band is calculated.

Equation 2 is a calculation formula based on an approximate expression of Lambert-Beer's law.
In Formula 2, n = 1 refers to “a group composed of alkane and alkene”, n = 2 refers to “a group composed of aromatic hydrocarbon”, and n = 3 refers to “a group composed of alkyne”.
In Equation 2, X ₁ is “absorbance of hydrocarbons belonging to the group consisting of alkane and alkene (light absorption amount)”, and X ₂ is “absorbance of hydrocarbons belonging to the group consisting of aromatic hydrocarbons (light absorption amount). ) ”, X ₃ refers to“ absorbance (absorption amount of light) of hydrocarbons belonging to the group consisting of alkynes ”.
In Equation 2, “I ₁ ” is the light intensity of “absorption wavelength band of hydrocarbon belonging to the group consisting of alkane and alkene” in the corrected absorption spectrum, and “I ₂ ” is “group consisting of aromatic hydrocarbon” in the corrected absorption spectrum. “I ₃ ” refers to the light intensity of the “absorption wavelength band of hydrocarbons belonging to the group consisting of alkynes” in the corrected absorption spectrum.
In Equation 2, “(I ₁ ) ₀ ” represents the light intensity of “absorption wavelength band of hydrocarbons belonging to the group consisting of alkane and alkene” in the reference spectrum, and “(I ₂ ) ₀ ” represents “aromatic carbonization” in the reference spectrum. The light intensity of “absorption wavelength band of hydrocarbons belonging to the group consisting of hydrogen”, “(I ₃ ) ₀ ” refers to the light intensity of “absorption wavelength band of hydrocarbons belonging to the group consisting of alkyne” in the reference spectrum.
Number 2, in the measurement conditions sufficient amount is _{ensured, {In / (In) 0} } ≒ that 1 is _{satisfied, {In / (In) 0} } when the ≒ 1 is established Loge {an In / It is assumed that (In) ₀ } ≈ [{In / (In) ₀ } −1] ≈ − [{(In) ₀ / In} −1] holds.
In the present embodiment, the light absorption amount is calculated using Xn = {(In) ₀ -In} / (In), but the present invention is not limited to this. That is, the light absorption amount may be calculated using a calculation formula (Xn = {(In) ₀ -In}) in which the denominator In is omitted.

  Since the calculation of the light absorption amount in the THC measurement apparatus 300 (processing unit 391) does not require logarithmic calculation, the calculation of the light absorption amount in the THC measurement apparatus 100 (processing unit 191) and the THC measurement apparatus 200 (processing unit 291). ) Is superior in that the calculation load is small compared to the calculation of the light absorption amount in FIG. By reducing the load of calculation, it contributes to the speeding up of the calculation (as a result, the improvement of the high-speed response of the hydrocarbon concentration measurement) and the reduction of the cost of the apparatus related to the calculation.

Further, the THC measuring device 100 and the THC measuring device 200, when the gas container 40 rises in temperature due to heat conduction from the measurement target gas 1 and emits infrared light, the infrared light is a long wavelength component of the absorption spectrum. Since this is a disturbance factor, the disturbance factor caused by the infrared light emitted from the gas container 40 is usually eliminated by taking measures such as combining the lock-in amplifier 80 with an HPF (high pass filter).
However, since the input value when performing the logarithmic calculation may be a negative value when such a treatment is performed, the THC measuring apparatus 100 and the THC measuring apparatus 200 set the constant C for convenience in order to reliably perform the logarithmic calculation. Addition operation is performed.
Since the THC measurement apparatus 300 does not perform logarithmic calculation, the calculation for adding the constant C is not required, and the calculation load is smaller than that of the THC measurement apparatus 100 and the THC measurement apparatus 200.

The processing unit 391 calculates “the sum of the concentrations of hydrocarbons belonging to the group consisting of alkane and alkene” based on “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkane and alkene” calculated based on Equation 2. Based on the “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”, the “sum of the concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons” is calculated, and “from alkyne Based on the “absorbance in the absorption wavelength band of hydrocarbons belonging to a certain group”, “the sum of the concentrations of hydrocarbons belonging to the group consisting of alkynes” is calculated.
Specifically, the processing unit 391 includes the measurement target gas 1 as the product of the coefficient K1 stored in the processing unit 391 in advance and “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkane and alkene”. The “sum of the concentrations of hydrocarbons belonging to the group consisting of alkanes and alkenes” is calculated.
Similarly, the processing unit 391 is included in the measurement target gas 1 as the product of the coefficient K2 stored in advance in the processing unit 391 and “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons”. The “sum of the concentrations of hydrocarbons belonging to the group consisting of aromatic hydrocarbons” is calculated.
Similarly, the processing unit 391 obtains “from alkyne” contained in the measurement target gas 1 as the product of the coefficient K3 stored in advance in the processing unit 391 and “absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of alkyne”. The sum of the concentrations of hydrocarbons belonging to a certain group is calculated.

  The processing unit 391 calculates the above-mentioned “sum of the concentrations of hydrocarbons belonging to the group consisting of alkanes and alkenes”, “sum of the concentrations of hydrocarbons belonging to the groups consisting of aromatic hydrocarbons”, and “groups consisting of alkynes” As the sum of the “sum of the concentrations of hydrocarbons belonging to”, “the total hydrocarbon concentration of the gas 1 to be measured” is calculated.

  The processing unit 391 calculates the “sum of the concentrations of hydrocarbons belonging to the group consisting of alkanes and alkenes”, “the sum of the concentrations of hydrocarbons belonging to the groups consisting of aromatic hydrocarbons”, and “belonging to the group consisting of alkynes” “Sum of hydrocarbon concentrations” and “total hydrocarbon concentration of measurement target gas 1” are stored as appropriate.

The initial values of the coefficient K1, the coefficient K2, and the coefficient K3 are obtained by measuring a gas whose hydrocarbon composition is known in advance by the FID-GC or the like using the THC measuring device 100, and the group consisting of alkane and alkene. Calculation result of "absorbance in the absorption wavelength band of hydrocarbons belonging to", calculation result of "absorbance in the absorption wavelength band of hydrocarbons belonging to the group consisting of aromatic hydrocarbons", and absorption of hydrocarbons belonging to the group consisting of alkynes It is experimentally determined based on the calculation result of “absorbance in wavelength band”.
In the case of this embodiment, the sum of the concentrations of hydrocarbons belonging to each group and the total hydrocarbon concentration calculated by the processing unit 391 are calculated in the form of methane equivalent concentration values (ppmC). However, the calculation may be performed in a form such as a volume ratio.

As described above, the THC measuring apparatus 300 is
An infrared lamp 10 for generating light;
A spectroscope 20 for periodically changing the wavelength of light generated by the infrared lamp 10, and
A photodiode 30 for detecting the intensity of light whose wavelength has been varied by the spectroscope 20;
A gas container 40 which is disposed at a position sandwiched between the spectroscope 20 and the photodiode 30 in an optical path Z formed by the infrared lamp 10, the spectroscope 20 and the photodiode 30, can accommodate the measurement target gas 1 and can transmit light. When,
References including wavelength bands absorbed by (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes among the hydrocarbons contained in measurement target gas 1 The average value D1 of the light intensity in the non-absorption wavelength band in the spectrum A ₀ (λ) and the reference spectrum A ₀ (λ) is stored in advance, and the absorption of the measurement target gas 1 based on the light intensity detected by the photodiode 30. The spectrum B ₀ (λ) is calculated, the average value D2 of the light intensity in the non-absorption wavelength band in the absorption spectrum B ₀ (λ) is calculated, and the value obtained by dividing the average value D1 by the average value D2 is calculated as the absorption spectrum B ₀ ( The corrected absorption spectrum B ₁ (λ) is calculated by multiplying by λ), and the difference between the reference spectrum A ₀ (λ) and the corrected absorption spectrum B ₁ (λ) is calculated. (Strictly, the difference in light intensity), among the hydrocarbons contained in the gas 1 to be measured, (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, (c) alkyne The light absorption amount (in this embodiment, X ₁ , X _2, and X ₃ ) of the wavelength band absorbed by each of the groups is calculated, and based on the calculated light absorption amount corresponding to each group A data processing device 390 (more precisely, a processing unit 391) for calculating the concentration of hydrocarbons belonging to each group;
It comprises.
With this configuration, the THC measurement device 300 can cause disturbance factors (for example, the optical system (lens or the like) of the THC measurement device 300) or the inlet-side window member 42 and the outlet provided in the gas container 40 to change every moment. Gawamado member 43 is dirty, or the like gas container 40 is infrared light is radiated from the material constituting the temperature rising gas container 40 (metal or the like) by heat conduction from the measurement target gas 1) absorption spectrum B ₀ It is possible to eliminate the influence on (λ), and consequently the concentration of hydrocarbons contained in the measurement target gas 1 can be measured with high accuracy.

Below, 3rd embodiment of the hydrocarbon concentration measuring method based on this invention is described using FIG.
The third embodiment of the hydrocarbon concentration measuring method according to the present invention is a method of measuring the sum of the concentrations of hydrocarbons contained in the measurement target gas 1 using the THC measuring device 300.
As shown in FIG. 22, the third embodiment of the hydrocarbon concentration measuring method according to the present invention includes a detection step S3100, an absorption spectrum calculation step S3200, an average value calculation step S3300, a corrected absorption spectrum calculation step S3400, and a light absorption amount calculation step S3500. And a concentration calculation step S3600.

The detection step S3100 is a step in which the photodiode 30 detects the intensity of light generated by the infrared lamp 10 and transmitted through the measurement target gas 1 stored in the gas container 40.
In the present embodiment, the detection step S3100 is repeatedly performed at a predetermined cycle (spectral cycle of the spectrometer 20).

In the absorption spectrum calculation step S3200, the data processing device 390 (more precisely, the processing unit 391) calculates the absorption spectrum B ₀ (λ) of the measurement target gas 1 based on the intensity of light detected by the photodiode 30. It is a process to do.
If absorption spectrum calculation process S3200 is complete | finished, it will transfer to average value calculation process S3300.

The average value calculation step S3300 is a step in which the data processing device 390 (more precisely, the processing unit 391) calculates the average value D2 of the light intensity in the non-absorption wavelength band in the absorption spectrum B ₀ (λ).
When the average value calculating step S3300 is completed, the process proceeds to the corrected absorption spectrum calculating step S3400.

In the corrected absorption spectrum calculation step S3400, the data processing device 390 (more precisely, the processing unit 391) calculates the average value D1 of the light intensity in the non-absorption wavelength band in the reference spectrum A ₀ (λ) as the absorption spectrum B ₀ (λ by multiplying the average value absorption spectrum divided by the D2 B ₀ of the light intensity of the non-absorption band (lambda) in) is a step of calculating a corrected absorption spectrum B ₁ (lambda).
When the corrected absorption spectrum calculation step S3400 is completed, the process proceeds to the light absorption amount calculation step S3500.

In the light absorption amount calculation step S3500, the data processing device 390 (more precisely, the processing unit 391) is based on the difference between the reference spectrum A ₀ (λ) and the corrected absorption spectrum B ₁ (λ) (this embodiment). Then, based on these spectra and Equation 2, among the hydrocarbons contained in the measurement target gas 1, (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) consisting of alkynes. This is a step of calculating the amount of light absorption (X ₁ , X ₂ and X _{3 in} this embodiment) in the wavelength band that each of the groups absorbs.
When the light absorption amount calculating step S3500 is completed, the process proceeds to the concentration calculating step S3600.

  In the concentration calculation step S3600, the data processing device 390 (more precisely, the processing unit 391) has (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. This is a step of calculating the concentration of hydrocarbons belonging to each group based on the amount of light absorbed by each of the above.

As described above, the third embodiment of the hydrocarbon concentration measuring method according to the present invention is:
An infrared lamp 10 for generating light;
A spectroscope 20 for periodically changing the wavelength of light generated by the infrared lamp 10, and
A photodiode 30 for detecting the intensity of light whose wavelength has been varied by the spectroscope 20;
A gas container 40 which is disposed at a position sandwiched between the spectroscope 20 and the photodiode 30 in an optical path Z formed by the infrared lamp 10, the spectroscope 20 and the photodiode 30, can accommodate the measurement target gas 1 and can transmit light. When,
References including wavelength bands absorbed by (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes among the hydrocarbons contained in measurement target gas 1 The average value D1 of the light intensity in the non-absorption wavelength band in the spectrum A ₀ (λ) and the reference spectrum A ₀ (λ) is stored in advance, and the measurement target gas 1 is based on the light intensity detected by the photodiode 30. A data processing device 390 (more precisely, a processing unit 391) for calculating the concentration of the contained hydrocarbon;
A method for measuring the concentration of hydrocarbons contained in the gas 1 to be measured using a THC measuring device 300 comprising:
Detection step S3100;
Absorption spectrum calculation step S3200,
An average value calculating step S3300;
Corrected absorption spectrum calculation step S3400,
A light absorption amount calculating step S3500;
Concentration calculation step S3600;
It comprises.
By configuring in this way, disturbance factors that change from moment to moment (for example, the optical system (lens or the like) of the THC measuring apparatus 300) or the inlet side window member 42 and the outlet side window member 43 provided in the gas container 40 become dirty. The effect that the temperature of the gas container 40 rises due to heat conduction from the measurement target gas 1 and infrared light is emitted from the material (metal, etc.) constituting the gas container 40) affects the absorption spectrum B ₀ (λ). Therefore, the concentration of hydrocarbons contained in the measurement target gas 1 can be measured with high accuracy.

1 Gas to be measured 10 Infrared lamp (light source)
20 Spectrometer 30 Photodiode (receiver)
40 Gas container 100 THC measuring device (hydrocarbon concentration measuring device)
190 Data processing device (concentration calculation device)

Claims (8)

A light source that generates light;
A spectroscope for periodically changing the wavelength of the light generated by the light source;
A light receiver for detecting the intensity of light whose wavelength has been varied by the spectroscope;
The optical path formed by the light source, the spectroscope and the light receiver is disposed at a position sandwiched by the spectroscope and the light receiver or a position sandwiched by the light source and the spectroscope, and can accommodate a measurement target gas, and A gas container capable of transmitting light;
Among the hydrocarbons contained in the measurement target gas, the shortest wavelength point in the reference spectrum from the reference spectrum including the wavelength band absorbed by each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbon, and the group consisting of alkyne. A second corrected reference spectrum obtained by adding a constant to the first corrected reference spectrum calculated by subtracting the light intensity of the light intensity at the longest wavelength point and the light intensity at the longest wavelength point is stored in advance and detected by the light receiver. By calculating the absorption spectrum of the gas to be measured based on the intensity of the measured light, and subtracting the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the absorption spectrum from the absorption spectrum. Calculate the first corrected absorption spectrum, the first correction The light intensity of the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the reference spectrum is the greater of the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the first corrected absorption spectrum. A second corrected absorption spectrum is calculated by multiplying the first corrected absorption spectrum by a value divided by the intensity, a third corrected absorption spectrum is calculated by adding the constant to the second corrected absorption spectrum, and the second corrected absorption spectrum is calculated. Of the hydrocarbons contained in the measurement target gas based on the corrected reference spectrum, the third corrected absorption spectrum, and the following Equation 1, a group consisting of alkane and alkene, a group consisting of aromatic hydrocarbons, a group consisting of alkynes, Calculate the amount of light absorption in the wavelength band that each absorbs, and apply to each calculated group. A density calculating apparatus for calculating the concentration of hydrocarbons belonging to each group based on the absorption of light,
A hydrocarbon concentration measuring apparatus comprising:

  The hydrocarbon concentration measuring apparatus according to claim 1, wherein the constant is zero or a positive value. A light source that generates light;
A spectroscope for periodically changing the wavelength of the light generated by the light source;
A light receiver for detecting the intensity of light whose wavelength has been varied by the spectroscope;
The optical path formed by the light source, the spectroscope and the light receiver is disposed at a position sandwiched by the spectroscope and the light receiver or a position sandwiched by the light source and the spectroscope, and can accommodate a measurement target gas, and A gas container capable of transmitting light;
Of the hydrocarbons contained in the measurement target gas, a wavelength that is equal to or less than the non-absorption wavelength of the reference spectrum including the wavelength band that each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbon, and the group consisting of alkyne absorbs. Dividing into a short wavelength side reference spectrum consisting of a band and a long wavelength side reference spectrum consisting of a wavelength band equal to or greater than the non-absorption wavelength, and subtracting the light intensity at the shortest wavelength point in the short wavelength side reference spectrum from the short wavelength side reference spectrum The first correction reference spectrum on the short wavelength side calculated by subtracting the light intensity at the longest wavelength point in the long wavelength side reference spectrum from the long wavelength side reference spectrum. The second corrected reference spectrum calculated in advance is stored by subtracting the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the reference spectrum and adding a constant from the reference spectrum. The absorption spectrum of the measurement target gas is calculated based on the intensity of light detected by the light receiver, and the absorption spectrum includes a short wavelength side absorption spectrum having a wavelength band equal to or less than the non-absorption wavelength and the non-absorption Dividing into a long wavelength side absorption spectrum consisting of a wavelength band equal to or greater than the wavelength, and subtracting the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum from the short wavelength side absorption spectrum, the short wavelength side first corrected absorption spectrum Calculated from the long wavelength side absorption spectrum to the long wavelength side absorption spectrum. The long wavelength side first corrected absorption spectrum is calculated by subtracting the light intensity at the longest wavelength point, and the light intensity at the longest wavelength point of the short wavelength side first corrected reference spectrum is calculated from the short wavelength side first corrected absorption spectrum. The short wavelength side second corrected absorption spectrum is calculated by multiplying the short wavelength side first corrected absorption spectrum by the value divided by the light intensity at the longest wavelength point, and the shortest wavelength point of the long wavelength side first corrected reference spectrum is calculated. A long wavelength side second corrected absorption spectrum is calculated by multiplying the long wavelength side first corrected absorption spectrum by dividing the light intensity by the light intensity at the shortest wavelength point of the long wavelength side first corrected absorption spectrum, When the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is smaller than the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the short wavelength side second correction is performed. A short wavelength side third corrected absorption spectrum is calculated by adding a constant to the absorption spectrum, and the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum and the long wavelength side absorption spectrum are added to the long wavelength side second corrected absorption spectrum. The long-wavelength-side third corrected absorption spectrum is calculated by adding the absolute value of the difference from the light intensity at the longest wavelength point and the constant, and the light intensity at the shortest wavelength point in the short-wavelength side absorption spectrum is the long-wavelength side. When the light intensity at the longest wavelength point in the absorption spectrum is larger than the light intensity at the longest wavelength point in the short wavelength side absorption spectrum, The third corrected absorption spectrum on the short wavelength side is calculated by adding the absolute value of the difference from the light intensity and the above constant. And calculating the long wavelength side third corrected absorption spectrum by adding the constant to the long wavelength side second corrected absorption spectrum, and setting the longest wavelength point of the short wavelength side third corrected absorption spectrum to the long wavelength side third corrected spectrum. A third corrected absorption spectrum is generated by connecting to the shortest wavelength point of the corrected absorption spectrum, and the carbonization contained in the measurement target gas based on the second corrected reference spectrum, the third corrected absorption spectrum, and the following Equation 1 Calculates the amount of light absorbed in the wavelength band absorbed by each of the groups consisting of alkanes and alkenes, groups composed of aromatic hydrocarbons, and groups composed of alkynes of hydrogen, and absorbs the light corresponding to each calculated group. A concentration calculation device for calculating the concentration of hydrocarbons belonging to each group based on the amount;
A hydrocarbon concentration measuring apparatus comprising:

  The hydrocarbon concentration measuring apparatus according to claim 3, wherein the constant is zero or a positive value. A light source that generates light;
A spectroscope for periodically changing the wavelength of the light generated by the light source;
A light receiver for detecting the intensity of light whose wavelength has been varied by the spectroscope;
The optical path formed by the light source, the spectroscope and the light receiver is disposed at a position sandwiched by the spectroscope and the light receiver or a position sandwiched by the light source and the spectroscope, and can accommodate a measurement target gas, and A gas container capable of transmitting light;
Among the hydrocarbons contained in the measurement target gas, the shortest wavelength point in the reference spectrum from the reference spectrum including the wavelength band absorbed by each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbon, and the group consisting of alkyne. The second correction reference spectrum obtained by adding a constant to the first correction reference spectrum calculated by subtracting the light intensity of the light intensity at the longest wavelength point and the light intensity at the longest wavelength point is stored in advance and detected by the light receiver. A concentration calculating device that calculates the concentration of hydrocarbons contained in the measurement target gas based on the intensity of the emitted light;
A hydrocarbon concentration measuring method for measuring the concentration of hydrocarbons contained in the measurement target gas using a hydrocarbon concentration measuring apparatus comprising:
A detection step in which the light receiver detects the intensity of light generated by the light source and transmitted through the measurement target gas contained in the gas container;
An absorption spectrum calculating step in which the concentration calculating device calculates an absorption spectrum of the gas to be measured based on the intensity of light detected by the light receiver;
The concentration calculating device calculates a first corrected absorption spectrum by subtracting the light intensity of the light wavelength at the shortest wavelength point and the light intensity at the longest wavelength point in the absorption spectrum from the absorption spectrum, and calculating a first corrected absorption spectrum. Spectrum calculation step;
The concentration calculation device uses the light intensity at the shortest wavelength point in the first corrected absorption spectrum and the light intensity at the shortest wavelength point in the first corrected absorption spectrum. A second corrected absorption spectrum calculating step of calculating a second corrected absorption spectrum by multiplying the first corrected absorption spectrum by a value obtained by dividing the light intensity of the point by the larger light intensity;
A third corrected absorption spectrum calculating step in which the concentration calculating device calculates a third corrected absorption spectrum by adding the constant to the second corrected absorption spectrum;
From the aromatic hydrocarbon, the group consisting of alkane and alkene among the hydrocarbons contained in the gas to be measured based on the second corrected reference spectrum, the third corrected absorption spectrum, and the following formula 1, A light absorption amount calculating step for calculating an absorption amount of light in a wavelength band absorbed by each of the group consisting of alkyne,
The concentration calculation device calculates the concentration of hydrocarbons belonging to each group based on the amount of light absorbed by each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbons, and the group consisting of alkynes. A concentration calculation step;
A hydrocarbon concentration measuring method comprising:

  The hydrocarbon concentration measuring method according to claim 5, wherein the constant is zero or a positive value. A light source that generates light;
A spectroscope for periodically changing the wavelength of the light generated by the light source;
A light receiver for detecting the intensity of light whose wavelength has been varied by the spectroscope;
The optical path formed by the light source, the spectroscope and the light receiver is disposed at a position sandwiched by the spectroscope and the light receiver or a position sandwiched by the light source and the spectroscope, and can accommodate a measurement target gas, and A gas container capable of transmitting light;
Of the hydrocarbons contained in the measurement target gas, a wavelength that is equal to or less than the non-absorption wavelength of the reference spectrum including the wavelength band that each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbon, and the group consisting of alkyne absorbs. Dividing into a short wavelength side reference spectrum consisting of a band and a long wavelength side reference spectrum consisting of a wavelength band equal to or greater than the non-absorption wavelength, and subtracting the light intensity at the shortest wavelength point in the short wavelength side reference spectrum from the short wavelength side reference spectrum The first correction reference spectrum on the short wavelength side calculated by subtracting the light intensity at the longest wavelength point in the long wavelength side reference spectrum from the long wavelength side reference spectrum. The second corrected reference spectrum calculated in advance is stored by subtracting the light intensity at the shortest wavelength point and the light intensity at the longest wavelength point in the reference spectrum and adding a constant from the reference spectrum. A concentration calculating device that stores the concentration of hydrocarbons contained in the measurement target gas based on the intensity of light detected by the light receiver;
A hydrocarbon concentration measuring method for measuring the concentration of hydrocarbons contained in the measurement target gas using a hydrocarbon concentration measuring apparatus comprising:
A detection step in which the light receiver detects the intensity of light generated by the light source and transmitted through the measurement target gas contained in the gas container;
An absorption spectrum calculating step in which the concentration calculating device calculates an absorption spectrum of the gas to be measured based on the intensity of light detected by the light receiver;
The concentration calculation device divides the absorption spectrum into a short wavelength side absorption spectrum consisting of a wavelength band equal to or less than the non-absorption wavelength and a long wavelength side absorption spectrum consisting of a wavelength band equal to or greater than the non-absorption wavelength, and the short wavelength side The short wavelength side first corrected absorption spectrum is calculated by subtracting the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum from the absorption spectrum and the longest wavelength point in the long wavelength side absorption spectrum is calculated from the long wavelength side absorption spectrum. A first corrected absorption spectrum calculating step of calculating a long wavelength side first corrected absorption spectrum by subtracting the light intensity;
The concentration calculating device calculates a value obtained by dividing the light intensity at the longest wavelength point of the short wavelength side first corrected reference spectrum by the light intensity at the longest wavelength point of the short wavelength side first corrected absorption spectrum. The short-wavelength-side second corrected absorption spectrum is calculated by multiplying the corrected absorption spectrum, and the light intensity at the shortest wavelength point of the long-wavelength-side first corrected reference spectrum is calculated at the shortest-wavelength-side first corrected absorption spectrum. A second corrected absorption spectrum calculating step of calculating a long wavelength side second corrected absorption spectrum by multiplying the long wavelength side first corrected absorption spectrum by a value divided by the light intensity;
When the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is smaller than the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the concentration calculation device has a constant in the short wavelength side second corrected absorption spectrum. And calculating the short wavelength side third corrected absorption spectrum and adding the long wavelength side second corrected absorption spectrum to the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum and the longest wavelength in the long wavelength side absorption spectrum. The long wavelength side third corrected absorption spectrum is calculated by adding the absolute value of the difference from the light intensity at the point and the constant to calculate the longest wavelength point of the short wavelength side third corrected absorption spectrum, and the long wavelength side third corrected A third corrected absorption spectrum is generated by connecting to the shortest wavelength point of the absorption spectrum, and in the short wavelength side absorption spectrum When the light intensity at the short wavelength point is larger than the light intensity at the longest wavelength point in the long wavelength side absorption spectrum, the light intensity at the shortest wavelength point in the short wavelength side absorption spectrum is added to the short wavelength side second corrected absorption spectrum. By calculating the short wavelength side third corrected absorption spectrum by adding the absolute value of the difference from the light intensity at the longest wavelength point in the long wavelength side absorption spectrum and the constant, the long wavelength side second corrected absorption spectrum A long wavelength side third corrected absorption spectrum is calculated by adding a constant, and the longest wavelength point of the short wavelength side third corrected absorption spectrum is connected to the shortest wavelength point of the long wavelength side third corrected absorption spectrum. A third corrected absorption spectrum calculating step for generating a three corrected absorption spectrum;
From the aromatic hydrocarbon, the group consisting of alkane and alkene among the hydrocarbons contained in the gas to be measured based on the second corrected reference spectrum, the third corrected absorption spectrum, and the following formula 1, A light absorption amount calculating step for calculating an absorption amount of light in a wavelength band absorbed by each of the group consisting of alkyne,
The concentration calculation device calculates the concentration of hydrocarbons belonging to each group based on the amount of light absorbed by each of the group consisting of alkane and alkene, the group consisting of aromatic hydrocarbons, and the group consisting of alkynes. A concentration calculation step;
A hydrocarbon concentration measuring method comprising:

  The hydrocarbon concentration measuring method according to claim 7, wherein the constant is zero or a positive value.

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