WO2022113603A1 - Gas analysis device, gas analysis method, and program for gas analysis device - Google Patents

Abstract

The present invention facilitates determination of a replacement timing for a drying agent used in a gas analysis device and reduces the work associated with said determination, and moreover provides a gas analysis device 100 comprising a drying agent 7 that absorbs moisture included in sampled air, the gas analysis device 100 analyzing components in a gas being measured by using air that has passed through the drying agent 7, wherein the gas analysis device 100 comprises a sensor unit 10 that measures the temperature and/or humidity of the air before the air passes through the drying agent 7, and a moisture amount calculation unit 11 that calculates the amount of moisture absorbed by the drying agent 7 using the temperature and/or humidity measured by the sensor unit 10.

Description

Gas analyzer, gas analysis method, program for gas analyzer

The present invention relates to a gas analyzer, a gas analysis method, and a program for a gas analyzer.

For example, as a gas analyzer for measuring NO _X contained in exhaust gas, as shown in Patent Document 1, there is a gas analyzer using a chemiluminescence method (CLD). The gas analyzer using this CLD is equipped with an ozone generator that generates ozone ₍ O3) required for chemiluminescence inside the device. Since this ozone generator generates O3 from the atmosphere sampled as an ozone source separately from the exhaust gas sampling _, the detection value of CLD is affected by the decrease in the amount of ozone generated and the quenching effect by the moisture contained in the atmosphere. Will receive.

Therefore, in the conventional gas analyzer using CLD, the influence of moisture contained in the atmosphere is reduced by passing the atmosphere introduced into the ozone generator through a desiccant such as silica gel. If the moisture content of this desiccant exceeds the permissible value, it affects the detection value of CLD, so maintenance such as replacement of the desiccant is required before the moisture content that can be absorbed is exceeded.

Japanese Unexamined Patent Publication No. 2018-72032

However, if the gas analyzer is a vehicle-mounted type, it is difficult to determine the replacement time (maintenance time). This is because, unlike the bench test in which the temperature, humidity, and atmospheric pressure are controlled in the actual road driving test, the temperature, humidity, and atmospheric pressure fluctuate greatly depending on the climatic conditions at the time of the test, and thereby the moisture in the atmosphere during the test. This is because it is difficult to estimate the amount of water absorbed by the desiccant from the time of use because the amount also changes.

It should be noted that the user removes the desiccant before and after the test and compares it with the weight of the desiccant before and after the test to estimate whether or not it can be used in the next test. If the climatic conditions change, the drying capacity may be lost, and the work before and after the test becomes complicated.

Therefore, the present invention has been made to solve the above-mentioned problems, and it is possible to easily determine the maintenance time such as replacement of the desiccant used in the gas analyzer, and to reduce the work for making the determination. That is the main issue.

That is, the gas analyzer according to the present invention includes a desiccant that absorbs moisture contained in the atmosphere sampled as an ozone source, and analyzes the components in the gas to be measured using the air that has passed through the desiccant. In a gas analyzer, the drying is performed using at least one of the temperature or humidity measured by the sensor unit and the sensor unit that measures at least one of the temperature or humidity of the atmosphere before passing through the desiccant. It is characterized by including a water content calculation unit for calculating the water content absorbed by the agent.

With this gas analyzer, the amount of water absorbed by the desiccant is calculated using at least one of the temperature and humidity measured by the sensor unit, so the remaining amount of water that the desiccant can absorb (allowable amount of water). ) Can be determined, and the maintenance time such as replacement of the desiccant can be easily estimated. Further, since it is not necessary to measure the weight of the desiccant before and after the test as in the conventional case, it is possible to reduce the work for determining the maintenance time.

Further, it is desirable that the gas analyzer according to the present invention further includes an output unit that outputs a water content calculated by the water content calculation unit and an allowable water content set in the desiccant so as to be comparable.
With this configuration, it is easy to recognize the amount of remaining water that the desiccant can absorb, and it is possible to easily determine the timing of replacement of the desiccant.

Further, the gas analyzer according to the present invention compares the water content calculated by the water content calculation unit with the allowable water content set for the desiccant, and the desiccant is used based on the comparison result. It is desirable to further include a notification unit that outputs an alarm indicating that it is not possible.
With this configuration, since the device automatically determines the timing of the desiccant, it is possible to prevent a judgment error due to the subjective judgment of the user.

Based on the comparison result, it is desirable that the notification unit outputs a prior notification as a step before outputting the alarm.
With this configuration, the user can change the test plan, prepare a replacement desiccant, and the like.

In order to make the effect of the present invention even more remarkable, it is usually difficult to constantly monitor the analysis instruction value during the road driving test in the vehicle-mounted type, and the climatic conditions are liable to change due to the road test. The analyzer below is preferred.
In this way, if it is a vehicle-mounted type, the climatic conditions are likely to change during the road driving test, so by calculating the water content using at least one of the temperature and humidity measured by the sensor unit, the desiccant Will be able to accurately recognize the amount of remaining water that can be absorbed.

In order to accurately calculate the amount of water absorbed by the desiccant, it is desirable that the water content calculation unit calculate the amount of water absorbed by the desiccant based on the following formula (1).

Here, W is the amount of water (g) absorbed by the desiccant, P _x is the atmospheric pressure (kPa) measured by the sensor unit, and P ₀ is the reference atmospheric pressure, for example, 101.3 ( kPa). L is the sampling flow rate of the atmosphere (cm ³ / sec), a (T _x ) is the saturated water vapor amount (g / cm ³ ) at the temperature T _x measured by the sensor unit, and T ₀ is. At a reference temperature, for example, 273.15 (° C.), RH _x is a relative humidity (%) measured by the sensor unit.

Further, in the gas analysis method according to the present invention, a gas that absorbs and removes the moisture contained in the sampled atmosphere with a desiccant and analyzes the components in the gas to be measured using the air that has passed through the desiccant. It is an analysis method that measures at least one of the temperature or humidity of the atmosphere before passing through the desiccant, and uses at least one of the measured temperature or humidity to absorb the amount of water absorbed by the desiccant. Is characterized by calculating.

Further, the program for a gas analyzer according to the present invention absorbs and removes the moisture contained in the sampled air with a desiccant, and analyzes the components in the gas to be measured using the air that has passed through the desiccant. A program used in a gas analyzer to acquire at least one of the temperature or humidity of the atmosphere before passing through the desiccant, and at least one of the temperature or humidity acquired by the acquisition unit. It is characterized in that the computer is provided with a function as a water content calculation unit for calculating the water content absorbed by the desiccant.

According to the present invention described above, it is possible to facilitate the determination of the replacement timing of the desiccant used in the gas analyzer and reduce the work associated with the determination.

It is an overall schematic diagram of the gas analyzer which concerns on one Embodiment of this invention. It is a functional block diagram of the control device of the same embodiment. It is a schematic diagram which shows the display screen of the same embodiment. It is a schematic diagram which shows the modification of the display screen.

100 ... Gas analyzer 7 ... Drying agent 10 ... Sensor unit 11 ... Moisture content calculation unit 13 ... Output unit 15 ... Notification unit

Hereinafter, the gas analyzer 100 according to the embodiment of the present invention will be described with reference to the drawings.

<Device configuration>
The gas analyzer 100 of the present embodiment is, for example, a vehicle-mounted type mounted on a vehicle, and analyzes components in exhaust gas discharged from the vehicle during a road driving test. Examples of the vehicle include an engine vehicle, a hybrid vehicle, and a plug-in hybrid vehicle.

Specifically, the gas analyzer 100 continuously measures the concentration of nitrogen oxides (NO _X ) in the exhaust gas by the chemiluminescence (CLD) method (chemiluminescence method). Even if the gas analyzer 100 includes an analyzer using a non-dispersed infrared absorption (NDIR) method, an analyzer using a hydrogen flame ionization (FID) method, and a condensed particle counter (CPC). good.

Then, as shown in FIG. 1, the gas analyzer 100 includes an exhaust gas flow path 2 through which the sampled exhaust gas flows, a CLD detector 3 provided in the exhaust gas flow path 2 and detecting NO in the exhaust gas, and the said gas analyzer 100. An ozone gas introduction path 4 that introduces ozone gas (O ₃ ) into the CLD detector 3, an ozone generator 5 that is provided in the ozone gas introduction path 4 and generates ozone gas from the atmosphere, and an ozone generator 5 that introduces the atmosphere. It includes an air introduction path 6 and a desiccant 7 such as silica gel, which is provided in the air introduction path 6 and absorbs moisture in the atmosphere.

The exhaust gas flow path 2 is provided with a _NOX converter 8 having a catalyst that reduces NO ₂ contained in the sampled exhaust gas to NO. When the exhaust gas passes through the NO _X converter 8, NO ₂ is reduced to NO, NO _X (NO + NO ₂ ) is detected by the CLD detector 3, and the concentration of NO _X can be measured.

Further, the exhaust gas flow path 2 is provided with a bypass path 21 that bypasses the NO _X converter 8, and by flowing the exhaust gas through the bypass path 21, NO is detected by the CLD detector 3 and the concentration of NO is determined. Can be measured. Further, since the concentration of NO _X and the concentration of NO can be measured by this flow path configuration, the concentration of NO ₂ can be measured by calculating the difference between them. An ozone decomposer 9 for decomposing ozone gas is provided on the downstream side of the CLD detector 3 in the exhaust gas flow path 2.

The CLD detector 3 includes a reactor in which the exhaust gas from the exhaust gas flow path 2 and the ozone gas from the ozone gas introduction path 4 are introduced, and a NO oxidation reaction by the ozone gas occurs in the reactor. A part of NO ₂ generated at this time becomes an excited state, and the excitation energy when returning from this excited state to the ground state is emitted as a photon. This phenomenon is called chemiluminescence. Then, the NO concentration of the sample gas can be measured by detecting the emission intensity of this chemiluminescence with a photoelectric element.

As shown in FIGS. 1 and 2, the gas analyzer 100 of the present embodiment has a sensor unit 10 for measuring the temperature, humidity, and pressure of the atmosphere before passing through the desiccant 7, and a sensor unit 10. It is provided with a moisture content calculation unit 11 for calculating the moisture content absorbed by the desiccant 7 using at least one of the measured temperature and humidity.

The sensor unit 10 passes through the temperature sensor 10a that measures the temperature of the atmosphere before passing through the desiccant 7, the humidity sensor 10b that measures the relative humidity of the atmosphere before passing through the desiccant 7, and the desiccant 7. It has a humidity sensor 10c that measures the humidity of the previous atmosphere. These sensors 10a, 10b, and 10c continuously measure the ambient temperature, relative humidity, and atmospheric pressure of the gas analyzer 100. As the sensor unit 10, a temperature sensor, a humidity sensor, and a barometric pressure sensor mounted on the vehicle may be used.

As shown in FIG. 2, the water content calculation unit 11 exerts its function by the control device COM of the gas analyzer 100. The control device COM is a dedicated or general-purpose computer having a CPU, an internal memory, an input / output interface, an AD converter, and the like. Further, the control device COM includes a data acquisition unit 12 that acquires temperature data, humidity data, and barometric pressure data from the sensor unit 10.

Specifically, the water content calculation unit 11 calculates the water content absorbed by the desiccant 7 based on the following formula (1).

Here, W is the amount of water (g) absorbed by the desiccant 7, P _x is the atmospheric pressure (kPa) measured by the atmospheric pressure sensor 10c, and P ₀ is the reference atmospheric pressure, for example, 101.3 ( kPa). L is the sampling flow rate of the atmosphere (cm ³ / sec), a (T _x ) is the saturated water vapor amount (g / cm ³ ) at the temperature T _x measured by the temperature sensor 10a, and T ₀ is. For example, 273.15 (° C.) at a reference temperature, and RH _x is a relative humidity (%) measured by the humidity sensor 10b.

Here, assuming that the temperature at a certain moment is T ₁ (° C) and the relative humidity is RH ₁ (%), the water content w ₁ (g / cm ³ ) per unit volume contained in the atmosphere at that time is T ₁ . The saturated water vapor amount of is expressed by the following formula using a (T ₁ ) (g / cm ³ ).

The sampling flow rate L (cm ³ / sec) of the atmosphere flowing through the atmosphere introduction path 6 is set to a constant value by design. As a result, the weight W ₁ (g / sec) of water per unit time sucked by the gas analyzer 100 at a certain moment is expressed by the following equation.

From the above, the total amount W (g) of water absorbed by the desiccant 7 from the atmosphere during the measurement time t (sec) of the gas analyzer 100 can be calculated by the following formula.

The moisture-absorbable water content (allowable water content) W _silica of the desiccant 7 can be set by the user from the weight of the desiccant 7 and the specifications of the manufacturer.

The control device COM of the present embodiment further includes an output unit 13 that outputs a water content W calculated by the water content calculation unit 11 and an allowable water content W _silica set in the desiccant 7 in a comparable manner. There is. The function of the output unit 13 is exhibited by the control device COM of the gas analyzer 100.

As shown in FIG. 3, the output unit 13 of the present embodiment is configured to display a graph G1 showing the calculated water content W and the allowable water content W _silica on the display 14. The vertical axis of the graph G1 is the water content (g), and the horizontal axis is the elapsed time. In addition, the output unit 13 may display the ratio (%) of the calculated water content W to the allowable water content W _silica on the display 13.

In addition, as shown in FIG. 4, in the output unit 13, the vertical axis represents the residual water retention capacity (g) of the desiccant 7, and the horizontal axis may display the graph G2 of the elapsed time, or the graph G3. As described above, a graph in which the vertical axis is normalized by the allowable water content W _silia and displayed as a percentage may be displayed. In addition, X in FIG. 4 is (W / W _silica ) × 100 (%).

Further, the gas analyzer 100 compares the water content W calculated by the water content calculation unit 11 with the allowable water content W _silica set in the desiccant 7, and the desiccant 7 is used based on the comparison result. A notification unit 15 that outputs an alarm indicating that it is not possible may be further provided. The function of the notification unit 15 is exhibited by the control device COM of the gas analyzer 100. Here, as long as the calculated water content W does not reach the allowable water content W _silica , it can be used. That is, when the calculated water content W reaches the allowable water content W _silica , the notification unit 15 outputs an alarm indicating that the desiccant 7 cannot be used. Here, as a mode for outputting an alarm, it is conceivable to display alarm information (for example, a warning message) on the display 14, or to change the display mode of an icon for starting an application for displaying the graph G. ..

Further, the notification unit 15 may be configured to output a advance notification (PreCaution) as a step before outputting an alarm based on the comparison result between the calculated water content W and the allowable water content W _silica . .. For example, when the calculated water content W reaches X% (for example, 80%) of the allowable water content W _silica , it is conceivable to output a prior notice. Here, as an aspect of outputting the advance notification, the advance notification information (for example, an advance notification message) is displayed on the display 14, or the display mode of the icon for starting the application for displaying the graph G is changed. Can be considered.

In addition, the notification unit 15 estimates the remaining usable time of the desiccant 7 based on the comparison result between the calculated water content W and the allowable water content W _silica , and notifies the user of the usable time. It may be configured as follows. Here, as a method for estimating the usable time, the amount of remaining water that the desiccant 7 can absorb (W _silica -W), the temperature and humidity measured by the sensor unit, the atmospheric pressure, other usage modes, and so on. It is conceivable to obtain it from the usage record of (the slope of the graph of the calculated water content W) and the like.

<Effect of this embodiment>
According to the gas analyzer 100 of the present embodiment configured as described above, since at least one of the temperature and the humidity measured by the sensor unit 10 is used to calculate the water content W absorbed by the desiccant 7, the desiccant 7 can determine the amount of remaining water that can absorb moisture (W _silica -W), and can easily determine the maintenance time such as replacement of the desiccant 7. Further, since it is not necessary to measure the weight of the desiccant 7 before and after the test as in the conventional case, it is possible to reduce the work for determining the maintenance time.

<Other embodiments>
The present invention is not limited to the above embodiment.

For example, in the above embodiment, the sensor unit measures the temperature, humidity, and atmospheric pressure, and the measured temperature, humidity, and atmospheric pressure are used to calculate the amount of water absorbed by the desiccant. One of the temperature, humidity, and atmospheric pressure may be measured, and the other of temperature, humidity, and atmospheric pressure may be set as a set value, and the amount of water absorbed by the desiccant may be calculated from them.

Further, in the above embodiment, the concentration of nitrogen oxides (NO _X ) in the exhaust gas is measured by the CLD method using ozone generated from the atmosphere that has passed through the desiccant 7, but the desiccant 7 is used. It may be another gas analyzer that analyzes the components in the gas to be measured (for example, any component such as CO, CO ₂ or NO) using the passing air.

Further, the air that has passed through the desiccant 7 may be used as a diluting gas. Examples of the components in the gas to be measured at this time include particulate matter (Particulate Matter: PM) and the number of solid particles (Particle Number: PN). When used for measuring the number of solid particles, a part of the sampled exhaust gas may be filtered with a particle collection filter, and a desiccant may be further passed through the gas from which the floating solid particles have been removed, and the gas may be used as a diluting gas.

In addition, various modifications and combinations may be made as long as it does not contradict the gist of the present invention.

According to the present invention, it is possible to facilitate the determination of the replacement timing of the desiccant used in the gas analyzer and reduce the work associated with the determination.

Claims (8)

1. A gas analyzer that is equipped with a desiccant that absorbs moisture contained in the sampled air and analyzes the components in the gas to be measured using the air that has passed through the desiccant.
   A sensor unit that measures at least one of the temperature and humidity of the atmosphere before passing through the desiccant, and
   A gas analyzer comprising a water content calculation unit that calculates the water content absorbed by the desiccant using at least one of the temperature and humidity measured by the sensor unit.
2. The gas analyzer according to claim 1, further comprising an output unit that outputs the water content calculated by the water content calculation unit and the allowable water content set in the desiccant in a comparable manner.
3. A notification that compares the water content calculated by the water content calculation unit with the allowable water content set for the desiccant, and outputs an alarm indicating that the desiccant cannot be used based on the comparison result. The gas analyzer according to claim 1 or 2, further comprising a unit.
4. The gas analyzer according to claim 3, wherein the notification unit outputs a prior notification as a step before outputting the alarm based on the comparison result.
5. The gas analyzer according to any one of claims 1 to 4, which is a vehicle-mounted type and analyzes components in exhaust gas emitted from a vehicle.
6. The gas analyzer according to any one of claims 1 to 5, wherein the water content calculation unit calculates the water content absorbed by the desiccant based on the following formula (1).
   

   

   Here, W is the amount of water (g) absorbed by the desiccant, L is the sampling flow rate of the atmosphere (cm ³ / sec), and a (T _x ) is measured by the sensor unit. It is the saturated water vapor amount (g / cm ³ ) at the temperature Tx, and RH _x is the relative humidity (%) measured by the sensor unit.
7. It is a gas analysis method in which moisture contained in the sampled air is absorbed by a desiccant, and the components in the gas to be measured are analyzed using the air that has passed through the desiccant.
   Measure and measure at least one of the temperature or humidity of the atmosphere before passing through the desiccant.
   A gas analysis method for calculating the amount of water absorbed by the desiccant using at least one of the measured temperature and humidity.
8. A program used in a gas analyzer that absorbs moisture contained in the sampled air with a desiccant and analyzes the components in the gas to be measured using the air that has passed through the desiccant.
   An acquisition unit that acquires at least one of the temperature and humidity of the atmosphere before passing through the desiccant, and
   Gas analysis, characterized in that the computer is provided with a function as a water content calculation unit for calculating the water content absorbed by the desiccant using at least one of the temperature and humidity acquired by the acquisition unit. Program for the device.

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