JPH0572094A - Continuous measurement system for polution gas - Google Patents

Abstract

PURPOSE:To realize a continuous measurement of values corresponding to odor concentration measured in sensual tests and a continuous measurement of polution gas which automatically corrects water content in the measured gas. CONSTITUTION:The title system is constituted of a preprocessor part 1 and a measuring part 2. The preprocessor part 1 is constituted of a silica gel charger tank 3, a humidifier tank 4, a constant temperature tank 5, a flow controller 6 to control the mixing fraction of dry air and saturated air and a mixing tank 7 to mix uniformly the dry air and the saturated air. The measuring part 2 is constituted of a gas concentration detection sensor 8. By this, automatic correction of humidity in the measured gas and continuous measurement of gas concentration become possible. Also, by using a sensor for detecting gas concentration which has an organic film of bimolecular structure attached to a crystal oscillator, a continuous measurement of values corresponding to the odor concentration measured in sensual tests by the human sense of smell becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to continuous measurement and monitoring of pollution gas, odorous gas and the like.

[0002]

2. Description of the Related Art Conventionally, continuous measurement by a device of a value corresponding to the odor concentration measured by a sensory test has not been realized.
In addition, when continuously measuring pollution gas with a device using a semiconductor sensor, the amount of water is corrected by calculation after measurement whether the influence of water in the measurement gas is completely ignored.

[0003]

Currently, a semiconductor sensor or a lipid bilayer sensor is generally used as a gas sensor or an odor sensor. In a so-called lipid bilayer sensor in which a bilayer-structured organic film is attached to a crystal oscillator, it is possible to measure odors in nanogram units as weight, and human olfactory cells have a bilayer structure. There is an advantage that the value corresponding to the odor concentration of the sensory test measured in 1. can be measured. However, even when measuring the amount of tens of ppm (ppm is a unit of one millionth) in the measurement gas, the measurement gas contains water of several thousands to several tens of thousands ppm depending on the temperature. It is difficult to measure the odor without water content correction, and it is no exaggeration to say that the water weight is actually measured rather than the odor is actually measured. Similarly, in semiconductor sensors, it is a well-known fact that the influence of water on the measured value is extremely large, and if the absolute humidity of the standard air for setting the zero value is different from the absolute humidity of the measurement gas, an error will appear accordingly. However, a continuous measurement method that considers the influence of water in the measurement gas has not been realized, and even standard air that should be used for setting a zero value is not actually used. An object of the present invention is to continuously measure and monitor pollution gas by automatically correcting the amount of moisture contained in the measurement gas.

[0004]

In order to achieve the above object, air having an absolute humidity equal to the amount of water in the measurement gas, that is, the absolute humidity of the measurement gas, is manufactured, and it is set as a standard air to a zero value. If used, the effect of water content can be automatically corrected from the measured value. The present invention proposes two methods for achieving the above object.

The first method is to convert the temperature of the measurement gas of any temperature and humidity and the temperature of the standard air into a certain constant temperature, 15 ° C. or 25 ° C. in the present invention, by means of a thermostatic chamber, and measure the absolute humidity of the measurement gas. It is a method to create standard air with absolute humidity equal to. The gas or air having a temperature of 15 ° C. or 25 ° C. can be produced by passing the gas or air through a thermostat controlled at 15 ° C. or 25 ° C. Then, the relative humidity and absolute humidity of the measurement gas at that temperature are determined. On the other hand, to create standard air with the same absolute humidity, when the relative humidity of the measured gas is ψ% at that temperature, the amount of dry air containing no moisture and saturated air containing no more moisture at the same temperature are used. The amount of each (1-ψ / 100)
It can be achieved by mixing with ψ / 100. Controlling the amount of dry air and the amount of saturated air can be accomplished by a flow controller. It can also be obtained by passing air through a silica gel-filled tank sufficient to produce dry air. Further, when air is passed through water having a sufficient contact time, saturated air with saturated humidity is obtained. By using standard air with an absolute humidity equal to the absolute humidity of the measurement gas produced in this way, a sensor for the sensory test was performed by setting the zero value of the gas concentration detection sensor in which the organic film of the bimolecular structure was attached to the crystal oscillator. It is possible to continuously measure the value corresponding to the measured odor concentration. If a gas concentration detection sensor and a reference sensor are installed in the measurement unit, continuous measurement is possible at all times, and if a reference sensor is not installed, intermittent continuous measurement according to the measurement program will be performed. Measure the gas temperature at 15 ℃
Or, the significance of setting to 25 ° C is that the measured value of sulfurous acid gas is 15
The measured value at 25 ° C. has a significant meaning because the measured value in terms of ° C. is specified and the human sense of smell is the most sensitive around 25 ° C. Furthermore, some so-called lipid bilayer membrane sensors in which an organic membrane having a bimolecular structure is attached to a crystal oscillator have a temperature variation point near 30 ° C.
This is because it is desirable to apply the temperature below ° C.

The second method is a method of producing standard air having an absolute humidity equal to that of a measurement gas having an arbitrary temperature and humidity. There is no particular temperature limit when using a semiconductor sensor. Therefore, in this case, the temperature / humidity of the standard air is not changed and the temperature / humidity of the standard gas is
It is a method of converting to humidity. The first method to create standard air
The method is exactly the same as that of the above method except that the temperature of the constant temperature bath is controlled to be equal to the temperature of the measurement gas. Also, the first
In the method (1), the measurement gas was introduced into the constant temperature bath, and the relative humidity at the temperature of the constant temperature bath had to be measured. Therefore, the temperature / humidity of the measurement gas may be measured at the measurement unit or at a completely different place, for example, at the gas generation source. Also in the second method, continuous measurement is always possible when the reference sensor is provided, and intermittent continuous measurement according to the program is performed when the reference sensor is not installed.

[0007]

Embodiments of the present invention will be described with reference to the drawings.
The figure shows a gas concentration detection sensor consisting of a crystal oscillator with an organic film of bimolecular structure attached, and a continuous measurement system for pollution gas that measures the gas concentration corresponding to the odor concentration measured by sensory test. Indicates.

FIG. 2 shows a pollution gas continuous measuring system for controlling the temperature of the thermostatic chamber 5 to be equal to the temperature of the measuring gas.

In FIG. 1, the measurement gas is introduced into the system through the measurement gas connection port 20 of the pretreatment unit 1 by the gas suction pump 11 and passes through the constant temperature bath 5 maintained at a constant temperature of 15 ° C. or 25 ° C. Is adjusted to 15 ℃ or 25 ℃ during
The relative humidity ψ% is measured by the temperature / humidity sensor 10. On the other hand, the raw material air flows into the system from the air intake connection port 21 by the air pump 14, passes through the air filter 13, and is then sent to the silica gel filling tank 3 and the humidity increasing tank 4 provided in the constant temperature tank 5. Dry air is produced in the silica gel filled tank, and saturated air is produced in the humidification tank. The ratio of the dry air and the saturated air is calculated by the flow controller 6 (1-ψ / 1
00) and ψ / 100, mixed uniformly in the mixing tank 7 and standard air having an absolute humidity which is always equal to the absolute humidity of the measurement gas is created and sent to the measuring unit 2.

The measuring unit 2 is divided into two processes, a zero value setting / cleaning process and a measuring process.

In the zero value setting / cleaning process, when the gas suction pumps 11 and 12 are operated, the solenoid valves 15, 17 and 19 are operated.
Is opened and the solenoid valves 16 and 18 are closed. The standard air having the same absolute humidity as the measurement gas produced by the pretreatment unit 1 is the gas concentration detection sensor 8 and the reference sensor 9.
To the gas suction pump 1 after cleaning each sensor.
It is discharged out of the system by 2.

In the measuring process, the dust suction pump 11 is stopped,
The gas suction pump 12 is operating. Solenoid valve 15, 17
And 19 are closed and solenoid valves 16 and 18 are open. The standard air having the same absolute humidity as the measurement gas is discharged from the system by the air pump 14 via the reference sensor 9 and the solenoid valve 18. The measurement gas is discharged to the outside of the system by the gas suction pump 12 via the electromagnetic valve 16 and the gas concentration detection sensor 8.

Table 1 shows the results measured by the first method.

[0014]

[Table 1]

When a semiconductor sensor is used in FIG. 2, the measuring section 2 is divided into three steps, a zero value setting step, a measuring step and a purging step.

In the zero value setting step, the solenoid valves 16, 17 and 19 are opened and the solenoid valves 15 and 18 are closed. The gas suction pumps 11 and 12 operate. The measurement gas flows into the system from the measurement gas connection port 20 by the gas suction pump 11, and passes through the electromagnetic valve 17 to detect the temperature / humidity sensor 1.
The temperature and humidity are measured by 0 and then discharged to the outside of the system. The temperature / humidity sensor does not necessarily have to be installed in the measurement unit 2, and may be installed in a completely different place such as a gas generation source. The measured temperature and humidity are transmitted to the preprocessing unit 1 as an electric signal. In the pretreatment unit 1, the temperature of the constant temperature bath 5 is controlled to be equal to the temperature of the measurement gas, and at the same time, the amounts of dry air and saturated air are (1-ψ / 100) and ψ / according to the relative humidity ψ% of the measurement gas. The standard air, which is controlled by the flow rate controller 6 at a ratio of 100, is uniformly mixed in the mixing tank 7 and is equal to the absolute humidity of the measurement gas, and is sent to the measurement unit 2. It is discharged to the outside of the system via the valve 19.

In the measuring process, the gas suction pump 11 and the air pump 14 are stopped and the gas suction pump 12 is operated. The solenoid valves 16, 17 and 18 are closed, and the solenoid valves 15 and 19 are open. The measurement gas is a gas suction pump 1
2 is discharged to the outside of the system via the solenoid valves 15 and 19.

In the purging process, the gas suction pumps 11 and 1
2 is stopped and the air pump 14 is activated. Solenoid valve 15,
17 and 19 are closed, and the solenoid valves 16 and 18 are open. In the pretreatment unit 1, the saturated air flow rate is controlled by the flow rate controller 6
Becomes zero, all the flow rates are manufactured as dry air, sent to the measurement unit 2, and discharged to the outside of the system via the solenoid valve 16, the gas concentration detection sensor 8, and the solenoid valve 18. When the reference sensor 9 is installed, continuous measurement is possible at all times, and when the reference sensor is not installed, intermittent continuous measurement by the measurement program is performed.

[0019]

By providing the pretreatment section 1, standard air having the same absolute humidity as the measuring gas can always be produced, and the water content in the measuring gas can be automatically corrected. The silica gel-filled tank in the pretreatment section acts to create dry air with zero humidity, and the humidification tank acts to create air with saturated humidity. The constant temperature tank has the function of making the intake air equal to the temperature of the measurement gas, the flow rate controller has the function of determining the mixing ratio for producing standard air that is equal to the absolute humidity of the measurement gas, and the mixing tank has the function of mixing the measurement gas. It has the effect of creating standard air equal to absolute humidity. Further, controlling the temperature of the constant temperature bath to be a constant temperature of 15 ° C. and setting the temperature of the measuring gas to 15 ° C. has an effect of being able to comply with the regulation for obtaining a value in which the measured value of sulfurous acid gas is always converted to 15 ° C. In addition, controlling the temperature of the constant temperature bath at a constant temperature of 25 ° C and setting the temperature of the measurement gas to 25 ° C is the temperature at which the odor is most sensitively detected in the sensory test, and the crystal oscillator is used as a gas concentration detection sensor. The use of the sensor attached with the bilayer organic film serves to obtain a value corresponding to the odor concentration measured by the sensory test.

[0020]

[Effect] The pollution gas can be continuously measured without being affected by the moisture content of the measurement gas.

[0021]

[Brief description of drawings]

FIG. 1 is a pollution gas continuous measurement system for measuring a value corresponding to an odor concentration measured by a sensory test using a sensor in which a bilayer organic film is attached to a crystal oscillator.

FIG. 2 is a pollution gas continuous measurement system that uses a semiconductor sensor and is not affected by moisture in the measurement gas.

[Explanation of symbols]

 1 Pretreatment part 2 Measuring part 3 Silica gel filling tank 4 Humidification tank 5 Constant temperature tank 6 Flow controller 7 Mixing tank 8 Gas concentration detection sensor 9 Reference sensor 10 Temperature / humidity sensor 11 12 Gas suction pump 13 Air filter 14 Air pump 15 16, 17, 18, 19 Solenoid valve 20 Measurement gas connection port 21 Air intake connection port 22 Communication pipe

Claims (5)

[Claims] 1. A pollution gas comprising a pretreatment unit 1 for producing air having an absolute humidity equal to the absolute humidity of the measurement gas and a measurement unit 2 for detecting the gas concentration of the measurement gas. Continuous measurement system. 2. The pretreatment unit 1 comprises a silica gel filling tank 3 for producing dry air, a humidification tank 4 for producing air of saturated humidity, a constant temperature bath 5 for keeping a constant temperature, dry air and air of saturated humidity. Flow rate controller 6 for controlling the amount of dry air and a mixing tank 7 for uniformly mixing dry air and air of saturated humidity, and the amount of dry air created in the silica gel filling tank 3 and the saturated humidity created in the humidification tank 4. When the mixing ratio of the amount of the air is set to ψ% as the relative humidity of the measurement gas, the flow rate controller 6 determines (1-ψ
/ 100) and ψ / 100 are automatically controlled, and after being uniformly mixed in the mixing tank 7, the gas is sent to the gas concentration detection sensor 8 provided in the measuring unit 2. Continuous pollution gas measurement system. 3. The pollution gas continuous measuring system according to claim 2, wherein the temperature of the constant temperature bath 5 of the pretreatment section 1 is controlled to a constant temperature of 15 ° C. or 25 ° C. 4. The gas concentration detection sensor 8 of the measuring unit 2 is constituted by a sensor in which a bimolecular organic film is attached to a crystal oscillator, and the gas concentration has a value corresponding to the odor concentration measured by a sensory test. The continuous measurement system for pollutant gas according to claim 3, wherein the measurement is performed. 5. The pollution gas continuous measuring system according to claim 2, wherein the temperature of the constant temperature bath 5 of the pretreatment unit 1 is controlled to be equal to the temperature of the measuring gas.